Change venv

venv/Lib/site-packages/pip/__init__.py

@@ -1,6 +1,6 @@
 from typing import List, Optional
 
-__version__ = "21.2.4"
+__version__ = "23.1.2"
 
 
 def main(args: Optional[List[str]] = None) -> int:

venv/Lib/site-packages/pip/_internal/build_env.py

@@ -1,17 +1,15 @@
 """Build Environment used for isolation during sdist building
 """
 
-import contextlib
 import logging
 import os
 import pathlib
+import site
 import sys
 import textwrap
-import zipfile
 from collections import OrderedDict
-from sysconfig import get_paths
 from types import TracebackType
-from typing import TYPE_CHECKING, Iterable, Iterator, List, Optional, Set, Tuple, Type
+from typing import TYPE_CHECKING, Iterable, List, Optional, Set, Tuple, Type, Union
 
 from pip._vendor.certifi import where
 from pip._vendor.packaging.requirements import Requirement
@@ -19,8 +17,8 @@ from pip._vendor.packaging.version import Version
 
 from pip import __file__ as pip_location
 from pip._internal.cli.spinners import open_spinner
-from pip._internal.locations import get_platlib, get_prefixed_libs, get_purelib
-from pip._internal.metadata import get_environment
+from pip._internal.locations import get_platlib, get_purelib, get_scheme
+from pip._internal.metadata import get_default_environment, get_environment
 from pip._internal.utils.subprocess import call_subprocess
 from pip._internal.utils.temp_dir import TempDirectory, tempdir_kinds
 
@@ -30,62 +28,68 @@ if TYPE_CHECKING:
 logger = logging.getLogger(__name__)
 
 
-class _Prefix:
+def _dedup(a: str, b: str) -> Union[Tuple[str], Tuple[str, str]]:
+    return (a, b) if a != b else (a,)
 
-    def __init__(self, path):
-        # type: (str) -> None
+
+class _Prefix:
+    def __init__(self, path: str) -> None:
         self.path = path
         self.setup = False
-        self.bin_dir = get_paths(
-            'nt' if os.name == 'nt' else 'posix_prefix',
-            vars={'base': path, 'platbase': path}
-        )['scripts']
-        self.lib_dirs = get_prefixed_libs(path)
+        scheme = get_scheme("", prefix=path)
+        self.bin_dir = scheme.scripts
+        self.lib_dirs = _dedup(scheme.purelib, scheme.platlib)
 
 
-@contextlib.contextmanager
-def _create_standalone_pip() -> Iterator[str]:
-    """Create a "standalone pip" zip file.
+def get_runnable_pip() -> str:
+    """Get a file to pass to a Python executable, to run the currently-running pip.
 
-    The zip file's content is identical to the currently-running pip.
-    It will be used to install requirements into the build environment.
+    This is used to run a pip subprocess, for installing requirements into the build
+    environment.
     """
     source = pathlib.Path(pip_location).resolve().parent
 
-    # Return the current instance if `source` is not a directory. We can't build
-    # a zip from this, and it likely means the instance is already standalone.
     if not source.is_dir():
-        yield str(source)
-        return
+        # This would happen if someone is using pip from inside a zip file. In that
+        # case, we can use that directly.
+        return str(source)
 
-    with TempDirectory(kind="standalone-pip") as tmp_dir:
-        pip_zip = os.path.join(tmp_dir.path, "__env_pip__.zip")
-        kwargs = {}
-        if sys.version_info >= (3, 8):
-            kwargs["strict_timestamps"] = False
-        with zipfile.ZipFile(pip_zip, "w", **kwargs) as zf:
-            for child in source.rglob("*"):
-                zf.write(child, child.relative_to(source.parent).as_posix())
-        yield os.path.join(pip_zip, "pip")
+    return os.fsdecode(source / "__pip-runner__.py")
+
+
+def _get_system_sitepackages() -> Set[str]:
+    """Get system site packages
+
+    Usually from site.getsitepackages,
+    but fallback on `get_purelib()/get_platlib()` if unavailable
+    (e.g. in a virtualenv created by virtualenv<20)
+
+    Returns normalized set of strings.
+    """
+    if hasattr(site, "getsitepackages"):
+        system_sites = site.getsitepackages()
+    else:
+        # virtualenv < 20 overwrites site.py without getsitepackages
+        # fallback on get_purelib/get_platlib.
+        # this is known to miss things, but shouldn't in the cases
+        # where getsitepackages() has been removed (inside a virtualenv)
+        system_sites = [get_purelib(), get_platlib()]
+    return {os.path.normcase(path) for path in system_sites}
 
 
 class BuildEnvironment:
-    """Creates and manages an isolated environment to install build deps
-    """
+    """Creates and manages an isolated environment to install build deps"""
 
-    def __init__(self):
-        # type: () -> None
-        temp_dir = TempDirectory(
-            kind=tempdir_kinds.BUILD_ENV, globally_managed=True
-        )
+    def __init__(self) -> None:
+        temp_dir = TempDirectory(kind=tempdir_kinds.BUILD_ENV, globally_managed=True)
 
         self._prefixes = OrderedDict(
             (name, _Prefix(os.path.join(temp_dir.path, name)))
-            for name in ('normal', 'overlay')
+            for name in ("normal", "overlay")
         )
 
-        self._bin_dirs = []  # type: List[str]
-        self._lib_dirs = []  # type: List[str]
+        self._bin_dirs: List[str] = []
+        self._lib_dirs: List[str] = []
         for prefix in reversed(list(self._prefixes.values())):
             self._bin_dirs.append(prefix.bin_dir)
             self._lib_dirs.extend(prefix.lib_dirs)
@@ -93,15 +97,17 @@ class BuildEnvironment:
         # Customize site to:
         # - ensure .pth files are honored
         # - prevent access to system site packages
-        system_sites = {
-            os.path.normcase(site) for site in (get_purelib(), get_platlib())
-        }
-        self._site_dir = os.path.join(temp_dir.path, 'site')
+        system_sites = _get_system_sitepackages()
+
+        self._site_dir = os.path.join(temp_dir.path, "site")
         if not os.path.exists(self._site_dir):
             os.mkdir(self._site_dir)
-        with open(os.path.join(self._site_dir, 'sitecustomize.py'), 'w') as fp:
-            fp.write(textwrap.dedent(
-                '''
+        with open(
+            os.path.join(self._site_dir, "sitecustomize.py"), "w", encoding="utf-8"
+        ) as fp:
+            fp.write(
+                textwrap.dedent(
+                    """
                 import os, site, sys
 
                 # First, drop system-sites related paths.
@@ -124,54 +130,64 @@ class BuildEnvironment:
                 for path in {lib_dirs!r}:
                     assert not path in sys.path
                     site.addsitedir(path)
-                '''
-            ).format(system_sites=system_sites, lib_dirs=self._lib_dirs))
+                """
+                ).format(system_sites=system_sites, lib_dirs=self._lib_dirs)
+            )
 
-    def __enter__(self):
-        # type: () -> None
+    def __enter__(self) -> None:
         self._save_env = {
             name: os.environ.get(name, None)
-            for name in ('PATH', 'PYTHONNOUSERSITE', 'PYTHONPATH')
+            for name in ("PATH", "PYTHONNOUSERSITE", "PYTHONPATH")
         }
 
         path = self._bin_dirs[:]
-        old_path = self._save_env['PATH']
+        old_path = self._save_env["PATH"]
         if old_path:
             path.extend(old_path.split(os.pathsep))
 
         pythonpath = [self._site_dir]
 
-        os.environ.update({
-            'PATH': os.pathsep.join(path),
-            'PYTHONNOUSERSITE': '1',
-            'PYTHONPATH': os.pathsep.join(pythonpath),
-        })
+        os.environ.update(
+            {
+                "PATH": os.pathsep.join(path),
+                "PYTHONNOUSERSITE": "1",
+                "PYTHONPATH": os.pathsep.join(pythonpath),
+            }
+        )
 
     def __exit__(
         self,
-        exc_type,  # type: Optional[Type[BaseException]]
-        exc_val,  # type: Optional[BaseException]
-        exc_tb  # type: Optional[TracebackType]
-    ):
-        # type: (...) -> None
+        exc_type: Optional[Type[BaseException]],
+        exc_val: Optional[BaseException],
+        exc_tb: Optional[TracebackType],
+    ) -> None:
         for varname, old_value in self._save_env.items():
             if old_value is None:
                 os.environ.pop(varname, None)
             else:
                 os.environ[varname] = old_value
 
-    def check_requirements(self, reqs):
-        # type: (Iterable[str]) -> Tuple[Set[Tuple[str, str]], Set[str]]
+    def check_requirements(
+        self, reqs: Iterable[str]
+    ) -> Tuple[Set[Tuple[str, str]], Set[str]]:
         """Return 2 sets:
-            - conflicting requirements: set of (installed, wanted) reqs tuples
-            - missing requirements: set of reqs
+        - conflicting requirements: set of (installed, wanted) reqs tuples
+        - missing requirements: set of reqs
         """
         missing = set()
         conflicting = set()
         if reqs:
-            env = get_environment(self._lib_dirs)
+            env = (
+                get_environment(self._lib_dirs)
+                if hasattr(self, "_lib_dirs")
+                else get_default_environment()
+            )
             for req_str in reqs:
                 req = Requirement(req_str)
+                # We're explicitly evaluating with an empty extra value, since build
+                # environments are not provided any mechanism to select specific extras.
+                if req.marker is not None and not req.marker.evaluate({"extra": ""}):
+                    continue
                 dist = env.get_distribution(req.name)
                 if not dist:
                     missing.add(req_str)
@@ -180,40 +196,31 @@ class BuildEnvironment:
                     installed_req_str = f"{req.name}=={dist.version}"
                 else:
                     installed_req_str = f"{req.name}==={dist.version}"
-                if dist.version not in req.specifier:
+                if not req.specifier.contains(dist.version, prereleases=True):
                     conflicting.add((installed_req_str, req_str))
                 # FIXME: Consider direct URL?
         return conflicting, missing
 
     def install_requirements(
         self,
-        finder,  # type: PackageFinder
-        requirements,  # type: Iterable[str]
-        prefix_as_string,  # type: str
-        message  # type: str
-    ):
-        # type: (...) -> None
+        finder: "PackageFinder",
+        requirements: Iterable[str],
+        prefix_as_string: str,
+        *,
+        kind: str,
+    ) -> None:
         prefix = self._prefixes[prefix_as_string]
         assert not prefix.setup
         prefix.setup = True
         if not requirements:
             return
-        with contextlib.ExitStack() as ctx:
-            # TODO: Remove this block when dropping 3.6 support. Python 3.6
-            # lacks importlib.resources and pep517 has issues loading files in
-            # a zip, so we fallback to the "old" method by adding the current
-            # pip directory to the child process's sys.path.
-            if sys.version_info < (3, 7):
-                pip_runnable = os.path.dirname(pip_location)
-            else:
-                pip_runnable = ctx.enter_context(_create_standalone_pip())
-            self._install_requirements(
-                pip_runnable,
-                finder,
-                requirements,
-                prefix,
-                message,
-            )
+        self._install_requirements(
+            get_runnable_pip(),
+            finder,
+            requirements,
+            prefix,
+            kind=kind,
+        )
 
     @staticmethod
     def _install_requirements(
@@ -221,74 +228,84 @@ class BuildEnvironment:
         finder: "PackageFinder",
         requirements: Iterable[str],
         prefix: _Prefix,
-        message: str,
+        *,
+        kind: str,
     ) -> None:
-        args = [
-            sys.executable, pip_runnable, 'install',
-            '--ignore-installed', '--no-user', '--prefix', prefix.path,
-            '--no-warn-script-location',
-        ]  # type: List[str]
+        args: List[str] = [
+            sys.executable,
+            pip_runnable,
+            "install",
+            "--ignore-installed",
+            "--no-user",
+            "--prefix",
+            prefix.path,
+            "--no-warn-script-location",
+        ]
         if logger.getEffectiveLevel() <= logging.DEBUG:
-            args.append('-v')
-        for format_control in ('no_binary', 'only_binary'):
+            args.append("-v")
+        for format_control in ("no_binary", "only_binary"):
             formats = getattr(finder.format_control, format_control)
-            args.extend(('--' + format_control.replace('_', '-'),
-                         ','.join(sorted(formats or {':none:'}))))
+            args.extend(
+                (
+                    "--" + format_control.replace("_", "-"),
+                    ",".join(sorted(formats or {":none:"})),
+                )
+            )
 
         index_urls = finder.index_urls
         if index_urls:
-            args.extend(['-i', index_urls[0]])
+            args.extend(["-i", index_urls[0]])
             for extra_index in index_urls[1:]:
-                args.extend(['--extra-index-url', extra_index])
+                args.extend(["--extra-index-url", extra_index])
         else:
-            args.append('--no-index')
+            args.append("--no-index")
         for link in finder.find_links:
-            args.extend(['--find-links', link])
+            args.extend(["--find-links", link])
 
         for host in finder.trusted_hosts:
-            args.extend(['--trusted-host', host])
+            args.extend(["--trusted-host", host])
         if finder.allow_all_prereleases:
-            args.append('--pre')
+            args.append("--pre")
         if finder.prefer_binary:
-            args.append('--prefer-binary')
-        args.append('--')
+            args.append("--prefer-binary")
+        args.append("--")
         args.extend(requirements)
         extra_environ = {"_PIP_STANDALONE_CERT": where()}
-        with open_spinner(message) as spinner:
-            call_subprocess(args, spinner=spinner, extra_environ=extra_environ)
+        with open_spinner(f"Installing {kind}") as spinner:
+            call_subprocess(
+                args,
+                command_desc=f"pip subprocess to install {kind}",
+                spinner=spinner,
+                extra_environ=extra_environ,
+            )
 
 
 class NoOpBuildEnvironment(BuildEnvironment):
-    """A no-op drop-in replacement for BuildEnvironment
-    """
+    """A no-op drop-in replacement for BuildEnvironment"""
 
-    def __init__(self):
-        # type: () -> None
+    def __init__(self) -> None:
         pass
 
-    def __enter__(self):
-        # type: () -> None
+    def __enter__(self) -> None:
         pass
 
     def __exit__(
         self,
-        exc_type,  # type: Optional[Type[BaseException]]
-        exc_val,  # type: Optional[BaseException]
-        exc_tb  # type: Optional[TracebackType]
-    ):
-        # type: (...) -> None
+        exc_type: Optional[Type[BaseException]],
+        exc_val: Optional[BaseException],
+        exc_tb: Optional[TracebackType],
+    ) -> None:
         pass
 
-    def cleanup(self):
-        # type: () -> None
+    def cleanup(self) -> None:
         pass
 
     def install_requirements(
         self,
-        finder,  # type: PackageFinder
-        requirements,  # type: Iterable[str]
-        prefix_as_string,  # type: str
-        message  # type: str
-    ):
-        # type: (...) -> None
+        finder: "PackageFinder",
+        requirements: Iterable[str],
+        prefix_as_string: str,
+        *,
+        kind: str,
+    ) -> None:
         raise NotImplementedError()

venv/Lib/site-packages/pip/_internal/cache.py

@@ -5,13 +5,14 @@ import hashlib
 import json
 import logging
 import os
-from typing import Any, Dict, List, Optional, Set
+from pathlib import Path
+from typing import Any, Dict, List, Optional
 
 from pip._vendor.packaging.tags import Tag, interpreter_name, interpreter_version
 from pip._vendor.packaging.utils import canonicalize_name
 
 from pip._internal.exceptions import InvalidWheelFilename
-from pip._internal.models.format_control import FormatControl
+from pip._internal.models.direct_url import DirectUrl
 from pip._internal.models.link import Link
 from pip._internal.models.wheel import Wheel
 from pip._internal.utils.temp_dir import TempDirectory, tempdir_kinds
@@ -19,9 +20,10 @@ from pip._internal.utils.urls import path_to_url
 
 logger = logging.getLogger(__name__)
 
+ORIGIN_JSON_NAME = "origin.json"
 
-def _hash_dict(d):
-    # type: (Dict[str, str]) -> str
+
+def _hash_dict(d: Dict[str, str]) -> str:
     """Return a stable sha224 of a dictionary."""
     s = json.dumps(d, sort_keys=True, separators=(",", ":"), ensure_ascii=True)
     return hashlib.sha224(s.encode("ascii")).hexdigest()
@@ -30,29 +32,16 @@ def _hash_dict(d):
 class Cache:
     """An abstract class - provides cache directories for data from links
 
-
-        :param cache_dir: The root of the cache.
-        :param format_control: An object of FormatControl class to limit
-            binaries being read from the cache.
-        :param allowed_formats: which formats of files the cache should store.
-            ('binary' and 'source' are the only allowed values)
+    :param cache_dir: The root of the cache.
     """
 
-    def __init__(self, cache_dir, format_control, allowed_formats):
-        # type: (str, FormatControl, Set[str]) -> None
+    def __init__(self, cache_dir: str) -> None:
         super().__init__()
         assert not cache_dir or os.path.isabs(cache_dir)
         self.cache_dir = cache_dir or None
-        self.format_control = format_control
-        self.allowed_formats = allowed_formats
 
-        _valid_formats = {"source", "binary"}
-        assert self.allowed_formats.union(_valid_formats) == _valid_formats
-
-    def _get_cache_path_parts(self, link):
-        # type: (Link) -> List[str]
-        """Get parts of part that must be os.path.joined with cache_dir
-        """
+    def _get_cache_path_parts(self, link: Link) -> List[str]:
+        """Get parts of part that must be os.path.joined with cache_dir"""
 
         # We want to generate an url to use as our cache key, we don't want to
         # just re-use the URL because it might have other items in the fragment
@@ -84,22 +73,11 @@ class Cache:
 
         return parts
 
-    def _get_candidates(self, link, canonical_package_name):
-        # type: (Link, str) -> List[Any]
-        can_not_cache = (
-            not self.cache_dir or
-            not canonical_package_name or
-            not link
-        )
+    def _get_candidates(self, link: Link, canonical_package_name: str) -> List[Any]:
+        can_not_cache = not self.cache_dir or not canonical_package_name or not link
         if can_not_cache:
             return []
 
-        formats = self.format_control.get_allowed_formats(
-            canonical_package_name
-        )
-        if not self.allowed_formats.intersection(formats):
-            return []
-
         candidates = []
         path = self.get_path_for_link(link)
         if os.path.isdir(path):
@@ -107,19 +85,16 @@ class Cache:
                 candidates.append((candidate, path))
         return candidates
 
-    def get_path_for_link(self, link):
-        # type: (Link) -> str
-        """Return a directory to store cached items in for link.
-        """
+    def get_path_for_link(self, link: Link) -> str:
+        """Return a directory to store cached items in for link."""
         raise NotImplementedError()
 
     def get(
         self,
-        link,            # type: Link
-        package_name,    # type: Optional[str]
-        supported_tags,  # type: List[Tag]
-    ):
-        # type: (...) -> Link
+        link: Link,
+        package_name: Optional[str],
+        supported_tags: List[Tag],
+    ) -> Link:
         """Returns a link to a cached item if it exists, otherwise returns the
         passed link.
         """
@@ -127,15 +102,12 @@ class Cache:
 
 
 class SimpleWheelCache(Cache):
-    """A cache of wheels for future installs.
-    """
+    """A cache of wheels for future installs."""
 
-    def __init__(self, cache_dir, format_control):
-        # type: (str, FormatControl) -> None
-        super().__init__(cache_dir, format_control, {"binary"})
+    def __init__(self, cache_dir: str) -> None:
+        super().__init__(cache_dir)
 
-    def get_path_for_link(self, link):
-        # type: (Link) -> str
+    def get_path_for_link(self, link: Link) -> str:
         """Return a directory to store cached wheels for link
 
         Because there are M wheels for any one sdist, we provide a directory
@@ -157,20 +129,17 @@ class SimpleWheelCache(Cache):
 
     def get(
         self,
-        link,            # type: Link
-        package_name,    # type: Optional[str]
-        supported_tags,  # type: List[Tag]
-    ):
-        # type: (...) -> Link
+        link: Link,
+        package_name: Optional[str],
+        supported_tags: List[Tag],
+    ) -> Link:
         candidates = []
 
         if not package_name:
             return link
 
         canonical_package_name = canonicalize_name(package_name)
-        for wheel_name, wheel_dir in self._get_candidates(
-            link, canonical_package_name
-        ):
+        for wheel_name, wheel_dir in self._get_candidates(link, canonical_package_name):
             try:
                 wheel = Wheel(wheel_name)
             except InvalidWheelFilename:
@@ -179,7 +148,9 @@ class SimpleWheelCache(Cache):
                 logger.debug(
                     "Ignoring cached wheel %s for %s as it "
                     "does not match the expected distribution name %s.",
-                    wheel_name, link, package_name,
+                    wheel_name,
+                    link,
+                    package_name,
                 )
                 continue
             if not wheel.supported(supported_tags):
@@ -201,27 +172,29 @@ class SimpleWheelCache(Cache):
 
 
 class EphemWheelCache(SimpleWheelCache):
-    """A SimpleWheelCache that creates it's own temporary cache directory
-    """
+    """A SimpleWheelCache that creates it's own temporary cache directory"""
 
-    def __init__(self, format_control):
-        # type: (FormatControl) -> None
+    def __init__(self) -> None:
         self._temp_dir = TempDirectory(
             kind=tempdir_kinds.EPHEM_WHEEL_CACHE,
             globally_managed=True,
         )
 
-        super().__init__(self._temp_dir.path, format_control)
+        super().__init__(self._temp_dir.path)
 
 
 class CacheEntry:
     def __init__(
         self,
-        link,  # type: Link
-        persistent,  # type: bool
+        link: Link,
+        persistent: bool,
     ):
         self.link = link
         self.persistent = persistent
+        self.origin: Optional[DirectUrl] = None
+        origin_direct_url_path = Path(self.link.file_path).parent / ORIGIN_JSON_NAME
+        if origin_direct_url_path.exists():
+            self.origin = DirectUrl.from_json(origin_direct_url_path.read_text())
 
 
 class WheelCache(Cache):
@@ -231,27 +204,23 @@ class WheelCache(Cache):
     when a certain link is not found in the simple wheel cache first.
     """
 
-    def __init__(self, cache_dir, format_control):
-        # type: (str, FormatControl) -> None
-        super().__init__(cache_dir, format_control, {'binary'})
-        self._wheel_cache = SimpleWheelCache(cache_dir, format_control)
-        self._ephem_cache = EphemWheelCache(format_control)
+    def __init__(self, cache_dir: str) -> None:
+        super().__init__(cache_dir)
+        self._wheel_cache = SimpleWheelCache(cache_dir)
+        self._ephem_cache = EphemWheelCache()
 
-    def get_path_for_link(self, link):
-        # type: (Link) -> str
+    def get_path_for_link(self, link: Link) -> str:
         return self._wheel_cache.get_path_for_link(link)
 
-    def get_ephem_path_for_link(self, link):
-        # type: (Link) -> str
+    def get_ephem_path_for_link(self, link: Link) -> str:
         return self._ephem_cache.get_path_for_link(link)
 
     def get(
         self,
-        link,            # type: Link
-        package_name,    # type: Optional[str]
-        supported_tags,  # type: List[Tag]
-    ):
-        # type: (...) -> Link
+        link: Link,
+        package_name: Optional[str],
+        supported_tags: List[Tag],
+    ) -> Link:
         cache_entry = self.get_cache_entry(link, package_name, supported_tags)
         if cache_entry is None:
             return link
@@ -259,11 +228,10 @@ class WheelCache(Cache):
 
     def get_cache_entry(
         self,
-        link,            # type: Link
-        package_name,    # type: Optional[str]
-        supported_tags,  # type: List[Tag]
-    ):
-        # type: (...) -> Optional[CacheEntry]
+        link: Link,
+        package_name: Optional[str],
+        supported_tags: List[Tag],
+    ) -> Optional[CacheEntry]:
         """Returns a CacheEntry with a link to a cached item if it exists or
         None. The cache entry indicates if the item was found in the persistent
         or ephemeral cache.
@@ -285,3 +253,20 @@ class WheelCache(Cache):
             return CacheEntry(retval, persistent=False)
 
         return None
+
+    @staticmethod
+    def record_download_origin(cache_dir: str, download_info: DirectUrl) -> None:
+        origin_path = Path(cache_dir) / ORIGIN_JSON_NAME
+        if origin_path.is_file():
+            origin = DirectUrl.from_json(origin_path.read_text())
+            # TODO: use DirectUrl.equivalent when https://github.com/pypa/pip/pull/10564
+            # is merged.
+            if origin.url != download_info.url:
+                logger.warning(
+                    "Origin URL %s in cache entry %s does not match download URL %s. "
+                    "This is likely a pip bug or a cache corruption issue.",
+                    origin.url,
+                    cache_dir,
+                    download_info.url,
+                )
+        origin_path.write_text(download_info.to_json(), encoding="utf-8")

venv/Lib/site-packages/pip/_internal/cli/autocompletion.py

@@ -59,6 +59,14 @@ def autocomplete() -> None:
                     print(dist)
                 sys.exit(1)
 
+        should_list_installables = (
+            not current.startswith("-") and subcommand_name == "install"
+        )
+        if should_list_installables:
+            for path in auto_complete_paths(current, "path"):
+                print(path)
+            sys.exit(1)
+
         subcommand = create_command(subcommand_name)
 
         for opt in subcommand.parser.option_list_all:
@@ -138,7 +146,7 @@ def auto_complete_paths(current: str, completion_type: str) -> Iterable[str]:
     starting with ``current``.
 
     :param current: The word to be completed
-    :param completion_type: path completion type(`file`, `path` or `dir`)i
+    :param completion_type: path completion type(``file``, ``path`` or ``dir``)
     :return: A generator of regular files and/or directories
     """
     directory, filename = os.path.split(current)

venv/Lib/site-packages/pip/_internal/cli/base_command.py

@@ -1,5 +1,6 @@
 """Base Command class, and related routines"""
 
+import functools
 import logging
 import logging.config
 import optparse
@@ -7,7 +8,9 @@ import os
 import sys
 import traceback
 from optparse import Values
-from typing import Any, List, Optional, Tuple
+from typing import Any, Callable, List, Optional, Tuple
+
+from pip._vendor.rich import traceback as rich_traceback
 
 from pip._internal.cli import cmdoptions
 from pip._internal.cli.command_context import CommandContextMixIn
@@ -21,12 +24,12 @@ from pip._internal.cli.status_codes import (
 from pip._internal.exceptions import (
     BadCommand,
     CommandError,
+    DiagnosticPipError,
     InstallationError,
     NetworkConnectionError,
     PreviousBuildDirError,
     UninstallationError,
 )
-from pip._internal.utils.deprecation import deprecated
 from pip._internal.utils.filesystem import check_path_owner
 from pip._internal.utils.logging import BrokenStdoutLoggingError, setup_logging
 from pip._internal.utils.misc import get_prog, normalize_path
@@ -85,10 +88,10 @@ class Command(CommandContextMixIn):
         # are present.
         assert not hasattr(options, "no_index")
 
-    def run(self, options: Values, args: List[Any]) -> int:
+    def run(self, options: Values, args: List[str]) -> int:
         raise NotImplementedError
 
-    def parse_args(self, args: List[str]) -> Tuple[Any, Any]:
+    def parse_args(self, args: List[str]) -> Tuple[Values, List[str]]:
         # factored out for testability
         return self.parser.parse_args(args)
 
@@ -119,6 +122,15 @@ class Command(CommandContextMixIn):
             user_log_file=options.log,
         )
 
+        always_enabled_features = set(options.features_enabled) & set(
+            cmdoptions.ALWAYS_ENABLED_FEATURES
+        )
+        if always_enabled_features:
+            logger.warning(
+                "The following features are always enabled: %s. ",
+                ", ".join(sorted(always_enabled_features)),
+            )
+
         # TODO: Try to get these passing down from the command?
         #       without resorting to os.environ to hold these.
         #       This also affects isolated builds and it should.
@@ -148,67 +160,66 @@ class Command(CommandContextMixIn):
                 )
                 options.cache_dir = None
 
-        if getattr(options, "build_dir", None):
-            deprecated(
-                reason=(
-                    "The -b/--build/--build-dir/--build-directory "
-                    "option is deprecated and has no effect anymore."
-                ),
-                replacement=(
-                    "use the TMPDIR/TEMP/TMP environment variable, "
-                    "possibly combined with --no-clean"
-                ),
-                gone_in="21.3",
-                issue=8333,
-            )
+        def intercepts_unhandled_exc(
+            run_func: Callable[..., int]
+        ) -> Callable[..., int]:
+            @functools.wraps(run_func)
+            def exc_logging_wrapper(*args: Any) -> int:
+                try:
+                    status = run_func(*args)
+                    assert isinstance(status, int)
+                    return status
+                except DiagnosticPipError as exc:
+                    logger.error("[present-rich] %s", exc)
+                    logger.debug("Exception information:", exc_info=True)
 
-        if "2020-resolver" in options.features_enabled:
-            logger.warning(
-                "--use-feature=2020-resolver no longer has any effect, "
-                "since it is now the default dependency resolver in pip. "
-                "This will become an error in pip 21.0."
-            )
+                    return ERROR
+                except PreviousBuildDirError as exc:
+                    logger.critical(str(exc))
+                    logger.debug("Exception information:", exc_info=True)
+
+                    return PREVIOUS_BUILD_DIR_ERROR
+                except (
+                    InstallationError,
+                    UninstallationError,
+                    BadCommand,
+                    NetworkConnectionError,
+                ) as exc:
+                    logger.critical(str(exc))
+                    logger.debug("Exception information:", exc_info=True)
+
+                    return ERROR
+                except CommandError as exc:
+                    logger.critical("%s", exc)
+                    logger.debug("Exception information:", exc_info=True)
+
+                    return ERROR
+                except BrokenStdoutLoggingError:
+                    # Bypass our logger and write any remaining messages to
+                    # stderr because stdout no longer works.
+                    print("ERROR: Pipe to stdout was broken", file=sys.stderr)
+                    if level_number <= logging.DEBUG:
+                        traceback.print_exc(file=sys.stderr)
+
+                    return ERROR
+                except KeyboardInterrupt:
+                    logger.critical("Operation cancelled by user")
+                    logger.debug("Exception information:", exc_info=True)
+
+                    return ERROR
+                except BaseException:
+                    logger.critical("Exception:", exc_info=True)
+
+                    return UNKNOWN_ERROR
+
+            return exc_logging_wrapper
 
         try:
-            status = self.run(options, args)
-            assert isinstance(status, int)
-            return status
-        except PreviousBuildDirError as exc:
-            logger.critical(str(exc))
-            logger.debug("Exception information:", exc_info=True)
-
-            return PREVIOUS_BUILD_DIR_ERROR
-        except (
-            InstallationError,
-            UninstallationError,
-            BadCommand,
-            NetworkConnectionError,
-        ) as exc:
-            logger.critical(str(exc))
-            logger.debug("Exception information:", exc_info=True)
-
-            return ERROR
-        except CommandError as exc:
-            logger.critical("%s", exc)
-            logger.debug("Exception information:", exc_info=True)
-
-            return ERROR
-        except BrokenStdoutLoggingError:
-            # Bypass our logger and write any remaining messages to stderr
-            # because stdout no longer works.
-            print("ERROR: Pipe to stdout was broken", file=sys.stderr)
-            if level_number <= logging.DEBUG:
-                traceback.print_exc(file=sys.stderr)
-
-            return ERROR
-        except KeyboardInterrupt:
-            logger.critical("Operation cancelled by user")
-            logger.debug("Exception information:", exc_info=True)
-
-            return ERROR
-        except BaseException:
-            logger.critical("Exception:", exc_info=True)
-
-            return UNKNOWN_ERROR
+            if not options.debug_mode:
+                run = intercepts_unhandled_exc(self.run)
+            else:
+                run = self.run
+                rich_traceback.install(show_locals=True)
+            return run(options, args)
         finally:
             self.handle_pip_version_check(options)

venv/Lib/site-packages/pip/_internal/cli/cmdoptions.py

@@ -10,9 +10,10 @@ pass on state. To be consistent, all options will follow this design.
 # The following comment should be removed at some point in the future.
 # mypy: strict-optional=False
 
+import importlib.util
+import logging
 import os
 import textwrap
-import warnings
 from functools import partial
 from optparse import SUPPRESS_HELP, Option, OptionGroup, OptionParser, Values
 from textwrap import dedent
@@ -21,7 +22,6 @@ from typing import Any, Callable, Dict, Optional, Tuple
 from pip._vendor.packaging.utils import canonicalize_name
 
 from pip._internal.cli.parser import ConfigOptionParser
-from pip._internal.cli.progress_bars import BAR_TYPES
 from pip._internal.exceptions import CommandError
 from pip._internal.locations import USER_CACHE_DIR, get_src_prefix
 from pip._internal.models.format_control import FormatControl
@@ -30,6 +30,8 @@ from pip._internal.models.target_python import TargetPython
 from pip._internal.utils.hashes import STRONG_HASHES
 from pip._internal.utils.misc import strtobool
 
+logger = logging.getLogger(__name__)
+
 
 def raise_option_error(parser: OptionParser, option: Option, msg: str) -> None:
     """
@@ -57,32 +59,6 @@ def make_option_group(group: Dict[str, Any], parser: ConfigOptionParser) -> Opti
     return option_group
 
 
-def check_install_build_global(
-    options: Values, check_options: Optional[Values] = None
-) -> None:
-    """Disable wheels if per-setup.py call options are set.
-
-    :param options: The OptionParser options to update.
-    :param check_options: The options to check, if not supplied defaults to
-        options.
-    """
-    if check_options is None:
-        check_options = options
-
-    def getname(n: str) -> Optional[Any]:
-        return getattr(check_options, n, None)
-
-    names = ["build_options", "global_options", "install_options"]
-    if any(map(getname, names)):
-        control = options.format_control
-        control.disallow_binaries()
-        warnings.warn(
-            "Disabling all use of wheels due to the use of --build-option "
-            "/ --global-option / --install-option.",
-            stacklevel=2,
-        )
-
-
 def check_dist_restriction(options: Values, check_target: bool = False) -> None:
     """Function for determining if custom platform options are allowed.
 
@@ -151,6 +127,18 @@ help_: Callable[..., Option] = partial(
     help="Show help.",
 )
 
+debug_mode: Callable[..., Option] = partial(
+    Option,
+    "--debug",
+    dest="debug_mode",
+    action="store_true",
+    default=False,
+    help=(
+        "Let unhandled exceptions propagate outside the main subroutine, "
+        "instead of logging them to stderr."
+    ),
+)
+
 isolated_mode: Callable[..., Option] = partial(
     Option,
     "--isolated",
@@ -165,13 +153,30 @@ isolated_mode: Callable[..., Option] = partial(
 
 require_virtualenv: Callable[..., Option] = partial(
     Option,
-    # Run only if inside a virtualenv, bail if not.
     "--require-virtualenv",
     "--require-venv",
     dest="require_venv",
     action="store_true",
     default=False,
-    help=SUPPRESS_HELP,
+    help=(
+        "Allow pip to only run in a virtual environment; "
+        "exit with an error otherwise."
+    ),
+)
+
+override_externally_managed: Callable[..., Option] = partial(
+    Option,
+    "--break-system-packages",
+    dest="override_externally_managed",
+    action="store_true",
+    help="Allow pip to modify an EXTERNALLY-MANAGED Python installation",
+)
+
+python: Callable[..., Option] = partial(
+    Option,
+    "--python",
+    dest="python",
+    help="Run pip with the specified Python interpreter.",
 )
 
 verbose: Callable[..., Option] = partial(
@@ -221,13 +226,9 @@ progress_bar: Callable[..., Option] = partial(
     "--progress-bar",
     dest="progress_bar",
     type="choice",
-    choices=list(BAR_TYPES.keys()),
+    choices=["on", "off"],
     default="on",
-    help=(
-        "Specify type of progress to be displayed ["
-        + "|".join(BAR_TYPES.keys())
-        + "] (default: %default)"
-    ),
+    help="Specify whether the progress bar should be used [on, off] (default: on)",
 )
 
 log: Callable[..., Option] = partial(
@@ -251,13 +252,26 @@ no_input: Callable[..., Option] = partial(
     help="Disable prompting for input.",
 )
 
+keyring_provider: Callable[..., Option] = partial(
+    Option,
+    "--keyring-provider",
+    dest="keyring_provider",
+    choices=["auto", "disabled", "import", "subprocess"],
+    default="auto",
+    help=(
+        "Enable the credential lookup via the keyring library if user input is allowed."
+        " Specify which mechanism to use [disabled, import, subprocess]."
+        " (default: disabled)"
+    ),
+)
+
 proxy: Callable[..., Option] = partial(
     Option,
     "--proxy",
     dest="proxy",
     type="str",
     default="",
-    help="Specify a proxy in the form [user:passwd@]proxy.server:port.",
+    help="Specify a proxy in the form scheme://[user:passwd@]proxy.server:port.",
 )
 
 retries: Callable[..., Option] = partial(
@@ -719,18 +733,6 @@ no_deps: Callable[..., Option] = partial(
     help="Don't install package dependencies.",
 )
 
-build_dir: Callable[..., Option] = partial(
-    PipOption,
-    "-b",
-    "--build",
-    "--build-dir",
-    "--build-directory",
-    dest="build_dir",
-    type="path",
-    metavar="dir",
-    help=SUPPRESS_HELP,
-)
-
 ignore_requires_python: Callable[..., Option] = partial(
     Option,
     "--ignore-requires-python",
@@ -750,6 +752,15 @@ no_build_isolation: Callable[..., Option] = partial(
     "if this option is used.",
 )
 
+check_build_deps: Callable[..., Option] = partial(
+    Option,
+    "--check-build-dependencies",
+    dest="check_build_deps",
+    action="store_true",
+    default=False,
+    help="Check the build dependencies when PEP517 is used.",
+)
+
 
 def _handle_no_use_pep517(
     option: Option, opt: str, value: str, parser: OptionParser
@@ -772,6 +783,16 @@ def _handle_no_use_pep517(
         """
         raise_option_error(parser, option=option, msg=msg)
 
+    # If user doesn't wish to use pep517, we check if setuptools and wheel are installed
+    # and raise error if it is not.
+    packages = ("setuptools", "wheel")
+    if not all(importlib.util.find_spec(package) for package in packages):
+        msg = (
+            f"It is not possible to use --no-use-pep517 "
+            f"without {' and '.join(packages)} installed."
+        )
+        raise_option_error(parser, option=option, msg=msg)
+
     # Otherwise, --no-use-pep517 was passed via the command-line.
     parser.values.use_pep517 = False
 
@@ -796,17 +817,38 @@ no_use_pep517: Any = partial(
     help=SUPPRESS_HELP,
 )
 
-install_options: Callable[..., Option] = partial(
+
+def _handle_config_settings(
+    option: Option, opt_str: str, value: str, parser: OptionParser
+) -> None:
+    key, sep, val = value.partition("=")
+    if sep != "=":
+        parser.error(f"Arguments to {opt_str} must be of the form KEY=VAL")  # noqa
+    dest = getattr(parser.values, option.dest)
+    if dest is None:
+        dest = {}
+        setattr(parser.values, option.dest, dest)
+    if key in dest:
+        if isinstance(dest[key], list):
+            dest[key].append(val)
+        else:
+            dest[key] = [dest[key], val]
+    else:
+        dest[key] = val
+
+
+config_settings: Callable[..., Option] = partial(
     Option,
-    "--install-option",
-    dest="install_options",
-    action="append",
-    metavar="options",
-    help="Extra arguments to be supplied to the setup.py install "
-    'command (use like --install-option="--install-scripts=/usr/local/'
-    'bin"). Use multiple --install-option options to pass multiple '
-    "options to setup.py install. If you are using an option with a "
-    "directory path, be sure to use absolute path.",
+    "-C",
+    "--config-settings",
+    dest="config_settings",
+    type=str,
+    action="callback",
+    callback=_handle_config_settings,
+    metavar="settings",
+    help="Configuration settings to be passed to the PEP 517 build backend. "
+    "Settings take the form KEY=VALUE. Use multiple --config-settings options "
+    "to pass multiple keys to the backend.",
 )
 
 build_options: Callable[..., Option] = partial(
@@ -855,6 +897,15 @@ disable_pip_version_check: Callable[..., Option] = partial(
     "of pip is available for download. Implied with --no-index.",
 )
 
+root_user_action: Callable[..., Option] = partial(
+    Option,
+    "--root-user-action",
+    dest="root_user_action",
+    default="warn",
+    choices=["warn", "ignore"],
+    help="Action if pip is run as a root user. By default, a warning message is shown.",
+)
+
 
 def _handle_merge_hash(
     option: Option, opt_str: str, value: str, parser: OptionParser
@@ -943,6 +994,11 @@ no_python_version_warning: Callable[..., Option] = partial(
 )
 
 
+# Features that are now always on. A warning is printed if they are used.
+ALWAYS_ENABLED_FEATURES = [
+    "no-binary-enable-wheel-cache",  # always on since 23.1
+]
+
 use_new_feature: Callable[..., Option] = partial(
     Option,
     "--use-feature",
@@ -950,7 +1006,11 @@ use_new_feature: Callable[..., Option] = partial(
     metavar="feature",
     action="append",
     default=[],
-    choices=["2020-resolver", "fast-deps", "in-tree-build"],
+    choices=[
+        "fast-deps",
+        "truststore",
+    ]
+    + ALWAYS_ENABLED_FEATURES,
     help="Enable new functionality, that may be backward incompatible.",
 )
 
@@ -961,7 +1021,9 @@ use_deprecated_feature: Callable[..., Option] = partial(
     metavar="feature",
     action="append",
     default=[],
-    choices=["legacy-resolver"],
+    choices=[
+        "legacy-resolver",
+    ],
     help=("Enable deprecated functionality, that will be removed in the future."),
 )
 
@@ -974,13 +1036,16 @@ general_group: Dict[str, Any] = {
     "name": "General Options",
     "options": [
         help_,
+        debug_mode,
         isolated_mode,
         require_virtualenv,
+        python,
         verbose,
         version,
         quiet,
         log,
         no_input,
+        keyring_provider,
         proxy,
         retries,
         timeout,

venv/Lib/site-packages/pip/_internal/cli/command_context.py

@@ -1,5 +1,5 @@
 from contextlib import ExitStack, contextmanager
-from typing import ContextManager, Iterator, TypeVar
+from typing import ContextManager, Generator, TypeVar
 
 _T = TypeVar("_T", covariant=True)
 
@@ -11,7 +11,7 @@ class CommandContextMixIn:
         self._main_context = ExitStack()
 
     @contextmanager
-    def main_context(self) -> Iterator[None]:
+    def main_context(self) -> Generator[None, None, None]:
         assert not self._in_main_context
 
         self._in_main_context = True

venv/Lib/site-packages/pip/_internal/cli/main.py

@@ -4,6 +4,7 @@ import locale
 import logging
 import os
 import sys
+import warnings
 from typing import List, Optional
 
 from pip._internal.cli.autocompletion import autocomplete
@@ -46,6 +47,14 @@ def main(args: Optional[List[str]] = None) -> int:
     if args is None:
         args = sys.argv[1:]
 
+    # Suppress the pkg_resources deprecation warning
+    # Note - we use a module of .*pkg_resources to cover
+    # the normal case (pip._vendor.pkg_resources) and the
+    # devendored case (a bare pkg_resources)
+    warnings.filterwarnings(
+        action="ignore", category=DeprecationWarning, module=".*pkg_resources"
+    )
+
     # Configure our deprecation warnings to be sent through loggers
     deprecation.install_warning_logger()
 

venv/Lib/site-packages/pip/_internal/cli/main_parser.py

@@ -2,9 +2,11 @@
 """
 
 import os
+import subprocess
 import sys
-from typing import List, Tuple
+from typing import List, Optional, Tuple
 
+from pip._internal.build_env import get_runnable_pip
 from pip._internal.cli import cmdoptions
 from pip._internal.cli.parser import ConfigOptionParser, UpdatingDefaultsHelpFormatter
 from pip._internal.commands import commands_dict, get_similar_commands
@@ -45,6 +47,25 @@ def create_main_parser() -> ConfigOptionParser:
     return parser
 
 
+def identify_python_interpreter(python: str) -> Optional[str]:
+    # If the named file exists, use it.
+    # If it's a directory, assume it's a virtual environment and
+    # look for the environment's Python executable.
+    if os.path.exists(python):
+        if os.path.isdir(python):
+            # bin/python for Unix, Scripts/python.exe for Windows
+            # Try both in case of odd cases like cygwin.
+            for exe in ("bin/python", "Scripts/python.exe"):
+                py = os.path.join(python, exe)
+                if os.path.exists(py):
+                    return py
+        else:
+            return python
+
+    # Could not find the interpreter specified
+    return None
+
+
 def parse_command(args: List[str]) -> Tuple[str, List[str]]:
     parser = create_main_parser()
 
@@ -57,6 +78,32 @@ def parse_command(args: List[str]) -> Tuple[str, List[str]]:
     #  args_else: ['install', '--user', 'INITools']
     general_options, args_else = parser.parse_args(args)
 
+    # --python
+    if general_options.python and "_PIP_RUNNING_IN_SUBPROCESS" not in os.environ:
+        # Re-invoke pip using the specified Python interpreter
+        interpreter = identify_python_interpreter(general_options.python)
+        if interpreter is None:
+            raise CommandError(
+                f"Could not locate Python interpreter {general_options.python}"
+            )
+
+        pip_cmd = [
+            interpreter,
+            get_runnable_pip(),
+        ]
+        pip_cmd.extend(args)
+
+        # Set a flag so the child doesn't re-invoke itself, causing
+        # an infinite loop.
+        os.environ["_PIP_RUNNING_IN_SUBPROCESS"] = "1"
+        returncode = 0
+        try:
+            proc = subprocess.run(pip_cmd)
+            returncode = proc.returncode
+        except (subprocess.SubprocessError, OSError) as exc:
+            raise CommandError(f"Failed to run pip under {interpreter}: {exc}")
+        sys.exit(returncode)
+
     # --version
     if general_options.version:
         sys.stdout.write(parser.version)

venv/Lib/site-packages/pip/_internal/cli/parser.py

@@ -6,7 +6,7 @@ import shutil
 import sys
 import textwrap
 from contextlib import suppress
-from typing import Any, Dict, Iterator, List, Tuple
+from typing import Any, Dict, Generator, List, Tuple
 
 from pip._internal.cli.status_codes import UNKNOWN_ERROR
 from pip._internal.configuration import Configuration, ConfigurationError
@@ -175,7 +175,9 @@ class ConfigOptionParser(CustomOptionParser):
             print(f"An error occurred during configuration: {exc}")
             sys.exit(3)
 
-    def _get_ordered_configuration_items(self) -> Iterator[Tuple[str, Any]]:
+    def _get_ordered_configuration_items(
+        self,
+    ) -> Generator[Tuple[str, Any], None, None]:
         # Configuration gives keys in an unordered manner. Order them.
         override_order = ["global", self.name, ":env:"]
 

venv/Lib/site-packages/pip/_internal/cli/progress_bars.py

@@ -1,250 +1,68 @@
-import itertools
-import sys
-from signal import SIGINT, default_int_handler, signal
-from typing import Any
+import functools
+from typing import Callable, Generator, Iterable, Iterator, Optional, Tuple
 
-from pip._vendor.progress.bar import Bar, FillingCirclesBar, IncrementalBar
-from pip._vendor.progress.spinner import Spinner
+from pip._vendor.rich.progress import (
+    BarColumn,
+    DownloadColumn,
+    FileSizeColumn,
+    Progress,
+    ProgressColumn,
+    SpinnerColumn,
+    TextColumn,
+    TimeElapsedColumn,
+    TimeRemainingColumn,
+    TransferSpeedColumn,
+)
 
-from pip._internal.utils.compat import WINDOWS
 from pip._internal.utils.logging import get_indentation
-from pip._internal.utils.misc import format_size
 
-try:
-    from pip._vendor import colorama
-# Lots of different errors can come from this, including SystemError and
-# ImportError.
-except Exception:
-    colorama = None
+DownloadProgressRenderer = Callable[[Iterable[bytes]], Iterator[bytes]]
 
 
-def _select_progress_class(preferred: Bar, fallback: Bar) -> Bar:
-    encoding = getattr(preferred.file, "encoding", None)
+def _rich_progress_bar(
+    iterable: Iterable[bytes],
+    *,
+    bar_type: str,
+    size: int,
+) -> Generator[bytes, None, None]:
+    assert bar_type == "on", "This should only be used in the default mode."
 
-    # If we don't know what encoding this file is in, then we'll just assume
-    # that it doesn't support unicode and use the ASCII bar.
-    if not encoding:
-        return fallback
-
-    # Collect all of the possible characters we want to use with the preferred
-    # bar.
-    characters = [
-        getattr(preferred, "empty_fill", ""),
-        getattr(preferred, "fill", ""),
-    ]
-    characters += list(getattr(preferred, "phases", []))
-
-    # Try to decode the characters we're using for the bar using the encoding
-    # of the given file, if this works then we'll assume that we can use the
-    # fancier bar and if not we'll fall back to the plaintext bar.
-    try:
-        "".join(characters).encode(encoding)
-    except UnicodeEncodeError:
-        return fallback
+    if not size:
+        total = float("inf")
+        columns: Tuple[ProgressColumn, ...] = (
+            TextColumn("[progress.description]{task.description}"),
+            SpinnerColumn("line", speed=1.5),
+            FileSizeColumn(),
+            TransferSpeedColumn(),
+            TimeElapsedColumn(),
+        )
     else:
-        return preferred
-
-
-_BaseBar: Any = _select_progress_class(IncrementalBar, Bar)
-
-
-class InterruptibleMixin:
-    """
-    Helper to ensure that self.finish() gets called on keyboard interrupt.
-
-    This allows downloads to be interrupted without leaving temporary state
-    (like hidden cursors) behind.
-
-    This class is similar to the progress library's existing SigIntMixin
-    helper, but as of version 1.2, that helper has the following problems:
-
-    1. It calls sys.exit().
-    2. It discards the existing SIGINT handler completely.
-    3. It leaves its own handler in place even after an uninterrupted finish,
-       which will have unexpected delayed effects if the user triggers an
-       unrelated keyboard interrupt some time after a progress-displaying
-       download has already completed, for example.
-    """
-
-    def __init__(self, *args: Any, **kwargs: Any) -> None:
-        """
-        Save the original SIGINT handler for later.
-        """
-        # https://github.com/python/mypy/issues/5887
-        super().__init__(*args, **kwargs)  # type: ignore
-
-        self.original_handler = signal(SIGINT, self.handle_sigint)
-
-        # If signal() returns None, the previous handler was not installed from
-        # Python, and we cannot restore it. This probably should not happen,
-        # but if it does, we must restore something sensible instead, at least.
-        # The least bad option should be Python's default SIGINT handler, which
-        # just raises KeyboardInterrupt.
-        if self.original_handler is None:
-            self.original_handler = default_int_handler
-
-    def finish(self) -> None:
-        """
-        Restore the original SIGINT handler after finishing.
-
-        This should happen regardless of whether the progress display finishes
-        normally, or gets interrupted.
-        """
-        super().finish()  # type: ignore
-        signal(SIGINT, self.original_handler)
-
-    def handle_sigint(self, signum, frame):  # type: ignore
-        """
-        Call self.finish() before delegating to the original SIGINT handler.
-
-        This handler should only be in place while the progress display is
-        active.
-        """
-        self.finish()
-        self.original_handler(signum, frame)
-
-
-class SilentBar(Bar):
-    def update(self) -> None:
-        pass
-
-
-class BlueEmojiBar(IncrementalBar):
-
-    suffix = "%(percent)d%%"
-    bar_prefix = " "
-    bar_suffix = " "
-    phases = ("\U0001F539", "\U0001F537", "\U0001F535")
-
-
-class DownloadProgressMixin:
-    def __init__(self, *args: Any, **kwargs: Any) -> None:
-        # https://github.com/python/mypy/issues/5887
-        super().__init__(*args, **kwargs)  # type: ignore
-        self.message: str = (" " * (get_indentation() + 2)) + self.message
-
-    @property
-    def downloaded(self) -> str:
-        return format_size(self.index)  # type: ignore
-
-    @property
-    def download_speed(self) -> str:
-        # Avoid zero division errors...
-        if self.avg == 0.0:  # type: ignore
-            return "..."
-        return format_size(1 / self.avg) + "/s"  # type: ignore
-
-    @property
-    def pretty_eta(self) -> str:
-        if self.eta:  # type: ignore
-            return f"eta {self.eta_td}"  # type: ignore
-        return ""
-
-    def iter(self, it):  # type: ignore
-        for x in it:
-            yield x
-            # B305 is incorrectly raised here
-            # https://github.com/PyCQA/flake8-bugbear/issues/59
-            self.next(len(x))  # noqa: B305
-        self.finish()
-
-
-class WindowsMixin:
-    def __init__(self, *args: Any, **kwargs: Any) -> None:
-        # The Windows terminal does not support the hide/show cursor ANSI codes
-        # even with colorama. So we'll ensure that hide_cursor is False on
-        # Windows.
-        # This call needs to go before the super() call, so that hide_cursor
-        # is set in time. The base progress bar class writes the "hide cursor"
-        # code to the terminal in its init, so if we don't set this soon
-        # enough, we get a "hide" with no corresponding "show"...
-        if WINDOWS and self.hide_cursor:  # type: ignore
-            self.hide_cursor = False
-
-        # https://github.com/python/mypy/issues/5887
-        super().__init__(*args, **kwargs)  # type: ignore
-
-        # Check if we are running on Windows and we have the colorama module,
-        # if we do then wrap our file with it.
-        if WINDOWS and colorama:
-            self.file = colorama.AnsiToWin32(self.file)  # type: ignore
-            # The progress code expects to be able to call self.file.isatty()
-            # but the colorama.AnsiToWin32() object doesn't have that, so we'll
-            # add it.
-            self.file.isatty = lambda: self.file.wrapped.isatty()
-            # The progress code expects to be able to call self.file.flush()
-            # but the colorama.AnsiToWin32() object doesn't have that, so we'll
-            # add it.
-            self.file.flush = lambda: self.file.wrapped.flush()
-
-
-class BaseDownloadProgressBar(WindowsMixin, InterruptibleMixin, DownloadProgressMixin):
-
-    file = sys.stdout
-    message = "%(percent)d%%"
-    suffix = "%(downloaded)s %(download_speed)s %(pretty_eta)s"
-
-
-class DefaultDownloadProgressBar(BaseDownloadProgressBar, _BaseBar):
-    pass
-
-
-class DownloadSilentBar(BaseDownloadProgressBar, SilentBar):
-    pass
-
-
-class DownloadBar(BaseDownloadProgressBar, Bar):
-    pass
-
-
-class DownloadFillingCirclesBar(BaseDownloadProgressBar, FillingCirclesBar):
-    pass
-
-
-class DownloadBlueEmojiProgressBar(BaseDownloadProgressBar, BlueEmojiBar):
-    pass
-
-
-class DownloadProgressSpinner(
-    WindowsMixin, InterruptibleMixin, DownloadProgressMixin, Spinner
-):
-
-    file = sys.stdout
-    suffix = "%(downloaded)s %(download_speed)s"
-
-    def next_phase(self) -> str:
-        if not hasattr(self, "_phaser"):
-            self._phaser = itertools.cycle(self.phases)
-        return next(self._phaser)
-
-    def update(self) -> None:
-        message = self.message % self
-        phase = self.next_phase()
-        suffix = self.suffix % self
-        line = "".join(
-            [
-                message,
-                " " if message else "",
-                phase,
-                " " if suffix else "",
-                suffix,
-            ]
+        total = size
+        columns = (
+            TextColumn("[progress.description]{task.description}"),
+            BarColumn(),
+            DownloadColumn(),
+            TransferSpeedColumn(),
+            TextColumn("eta"),
+            TimeRemainingColumn(),
         )
 
-        self.writeln(line)
+    progress = Progress(*columns, refresh_per_second=30)
+    task_id = progress.add_task(" " * (get_indentation() + 2), total=total)
+    with progress:
+        for chunk in iterable:
+            yield chunk
+            progress.update(task_id, advance=len(chunk))
 
 
-BAR_TYPES = {
-    "off": (DownloadSilentBar, DownloadSilentBar),
-    "on": (DefaultDownloadProgressBar, DownloadProgressSpinner),
-    "ascii": (DownloadBar, DownloadProgressSpinner),
-    "pretty": (DownloadFillingCirclesBar, DownloadProgressSpinner),
-    "emoji": (DownloadBlueEmojiProgressBar, DownloadProgressSpinner),
-}
+def get_download_progress_renderer(
+    *, bar_type: str, size: Optional[int] = None
+) -> DownloadProgressRenderer:
+    """Get an object that can be used to render the download progress.
 
-
-def DownloadProgressProvider(progress_bar, max=None):  # type: ignore
-    if max is None or max == 0:
-        return BAR_TYPES[progress_bar][1]().iter
+    Returns a callable, that takes an iterable to "wrap".
+    """
+    if bar_type == "on":
+        return functools.partial(_rich_progress_bar, bar_type=bar_type, size=size)
     else:
-        return BAR_TYPES[progress_bar][0](max=max).iter
+        return iter  # no-op, when passed an iterator

venv/Lib/site-packages/pip/_internal/cli/req_command.py

@@ -10,7 +10,7 @@ import os
 import sys
 from functools import partial
 from optparse import Values
-from typing import Any, List, Optional, Tuple
+from typing import TYPE_CHECKING, Any, List, Optional, Tuple
 
 from pip._internal.cache import WheelCache
 from pip._internal.cli import cmdoptions
@@ -22,6 +22,7 @@ from pip._internal.index.package_finder import PackageFinder
 from pip._internal.models.selection_prefs import SelectionPreferences
 from pip._internal.models.target_python import TargetPython
 from pip._internal.network.session import PipSession
+from pip._internal.operations.build.build_tracker import BuildTracker
 from pip._internal.operations.prepare import RequirementPreparer
 from pip._internal.req.constructors import (
     install_req_from_editable,
@@ -31,7 +32,6 @@ from pip._internal.req.constructors import (
 )
 from pip._internal.req.req_file import parse_requirements
 from pip._internal.req.req_install import InstallRequirement
-from pip._internal.req.req_tracker import RequirementTracker
 from pip._internal.resolution.base import BaseResolver
 from pip._internal.self_outdated_check import pip_self_version_check
 from pip._internal.utils.temp_dir import (
@@ -41,9 +41,33 @@ from pip._internal.utils.temp_dir import (
 )
 from pip._internal.utils.virtualenv import running_under_virtualenv
 
+if TYPE_CHECKING:
+    from ssl import SSLContext
+
 logger = logging.getLogger(__name__)
 
 
+def _create_truststore_ssl_context() -> Optional["SSLContext"]:
+    if sys.version_info < (3, 10):
+        raise CommandError("The truststore feature is only available for Python 3.10+")
+
+    try:
+        import ssl
+    except ImportError:
+        logger.warning("Disabling truststore since ssl support is missing")
+        return None
+
+    try:
+        import truststore
+    except ImportError:
+        raise CommandError(
+            "To use the truststore feature, 'truststore' must be installed into "
+            "pip's current environment."
+        )
+
+    return truststore.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
+
+
 class SessionCommandMixin(CommandContextMixIn):
 
     """
@@ -83,15 +107,27 @@ class SessionCommandMixin(CommandContextMixIn):
         options: Values,
         retries: Optional[int] = None,
         timeout: Optional[int] = None,
+        fallback_to_certifi: bool = False,
     ) -> PipSession:
-        assert not options.cache_dir or os.path.isabs(options.cache_dir)
+        cache_dir = options.cache_dir
+        assert not cache_dir or os.path.isabs(cache_dir)
+
+        if "truststore" in options.features_enabled:
+            try:
+                ssl_context = _create_truststore_ssl_context()
+            except Exception:
+                if not fallback_to_certifi:
+                    raise
+                ssl_context = None
+        else:
+            ssl_context = None
+
         session = PipSession(
-            cache=(
-                os.path.join(options.cache_dir, "http") if options.cache_dir else None
-            ),
+            cache=os.path.join(cache_dir, "http") if cache_dir else None,
             retries=retries if retries is not None else options.retries,
             trusted_hosts=options.trusted_hosts,
             index_urls=self._get_index_urls(options),
+            ssl_context=ssl_context,
         )
 
         # Handle custom ca-bundles from the user
@@ -115,6 +151,7 @@ class SessionCommandMixin(CommandContextMixIn):
 
         # Determine if we can prompt the user for authentication or not
         session.auth.prompting = not options.no_input
+        session.auth.keyring_provider = options.keyring_provider
 
         return session
 
@@ -141,7 +178,14 @@ class IndexGroupCommand(Command, SessionCommandMixin):
 
         # Otherwise, check if we're using the latest version of pip available.
         session = self._build_session(
-            options, retries=0, timeout=min(5, options.timeout)
+            options,
+            retries=0,
+            timeout=min(5, options.timeout),
+            # This is set to ensure the function does not fail when truststore is
+            # specified in use-feature but cannot be loaded. This usually raises a
+            # CommandError and shows a nice user-facing error, but this function is not
+            # called in that try-except block.
+            fallback_to_certifi=True,
         )
         with session:
             pip_self_version_check(session, options)
@@ -172,9 +216,10 @@ def warn_if_run_as_root() -> None:
     # checks: https://mypy.readthedocs.io/en/stable/common_issues.html
     if sys.platform == "win32" or sys.platform == "cygwin":
         return
-    if sys.platform == "darwin" or sys.platform == "linux":
-        if os.getuid() != 0:
-            return
+
+    if os.getuid() != 0:
+        return
+
     logger.warning(
         "Running pip as the 'root' user can result in broken permissions and "
         "conflicting behaviour with the system package manager. "
@@ -230,11 +275,12 @@ class RequirementCommand(IndexGroupCommand):
         cls,
         temp_build_dir: TempDirectory,
         options: Values,
-        req_tracker: RequirementTracker,
+        build_tracker: BuildTracker,
         session: PipSession,
         finder: PackageFinder,
         use_user_site: bool,
         download_dir: Optional[str] = None,
+        verbosity: int = 0,
     ) -> RequirementPreparer:
         """
         Create a RequirementPreparer instance for the given parameters.
@@ -265,14 +311,15 @@ class RequirementCommand(IndexGroupCommand):
             src_dir=options.src_dir,
             download_dir=download_dir,
             build_isolation=options.build_isolation,
-            req_tracker=req_tracker,
+            check_build_deps=options.check_build_deps,
+            build_tracker=build_tracker,
             session=session,
             progress_bar=options.progress_bar,
             finder=finder,
             require_hashes=options.require_hashes,
             use_user_site=use_user_site,
             lazy_wheel=lazy_wheel,
-            in_tree_build="in-tree-build" in options.features_enabled,
+            verbosity=verbosity,
         )
 
     @classmethod
@@ -363,10 +410,11 @@ class RequirementCommand(IndexGroupCommand):
         for req in args:
             req_to_add = install_req_from_line(
                 req,
-                None,
+                comes_from=None,
                 isolated=options.isolated_mode,
                 use_pep517=options.use_pep517,
                 user_supplied=True,
+                config_settings=getattr(options, "config_settings", None),
             )
             requirements.append(req_to_add)
 
@@ -376,6 +424,7 @@ class RequirementCommand(IndexGroupCommand):
                 user_supplied=True,
                 isolated=options.isolated_mode,
                 use_pep517=options.use_pep517,
+                config_settings=getattr(options, "config_settings", None),
             )
             requirements.append(req_to_add)
 
@@ -389,6 +438,9 @@ class RequirementCommand(IndexGroupCommand):
                     isolated=options.isolated_mode,
                     use_pep517=options.use_pep517,
                     user_supplied=True,
+                    config_settings=parsed_req.options.get("config_settings")
+                    if parsed_req.options
+                    else None,
                 )
                 requirements.append(req_to_add)
 

venv/Lib/site-packages/pip/_internal/cli/spinners.py

@@ -3,9 +3,7 @@ import itertools
 import logging
 import sys
 import time
-from typing import IO, Iterator
-
-from pip._vendor.progress import HIDE_CURSOR, SHOW_CURSOR
+from typing import IO, Generator, Optional
 
 from pip._internal.utils.compat import WINDOWS
 from pip._internal.utils.logging import get_indentation
@@ -25,7 +23,7 @@ class InteractiveSpinner(SpinnerInterface):
     def __init__(
         self,
         message: str,
-        file: IO[str] = None,
+        file: Optional[IO[str]] = None,
         spin_chars: str = "-\\|/",
         # Empirically, 8 updates/second looks nice
         min_update_interval_seconds: float = 0.125,
@@ -115,7 +113,7 @@ class RateLimiter:
 
 
 @contextlib.contextmanager
-def open_spinner(message: str) -> Iterator[SpinnerInterface]:
+def open_spinner(message: str) -> Generator[SpinnerInterface, None, None]:
     # Interactive spinner goes directly to sys.stdout rather than being routed
     # through the logging system, but it acts like it has level INFO,
     # i.e. it's only displayed if we're at level INFO or better.
@@ -138,8 +136,12 @@ def open_spinner(message: str) -> Iterator[SpinnerInterface]:
         spinner.finish("done")
 
 
+HIDE_CURSOR = "\x1b[?25l"
+SHOW_CURSOR = "\x1b[?25h"
+
+
 @contextlib.contextmanager
-def hidden_cursor(file: IO[str]) -> Iterator[None]:
+def hidden_cursor(file: IO[str]) -> Generator[None, None, None]:
     # The Windows terminal does not support the hide/show cursor ANSI codes,
     # even via colorama. So don't even try.
     if WINDOWS:

venv/Lib/site-packages/pip/_internal/commands/__init__.py

@@ -3,87 +3,107 @@ Package containing all pip commands
 """
 
 import importlib
-from collections import OrderedDict, namedtuple
+from collections import namedtuple
 from typing import Any, Dict, Optional
 
 from pip._internal.cli.base_command import Command
 
-CommandInfo = namedtuple('CommandInfo', 'module_path, class_name, summary')
+CommandInfo = namedtuple("CommandInfo", "module_path, class_name, summary")
 
-# The ordering matters for help display.
-#    Also, even though the module path starts with the same
-# "pip._internal.commands" prefix in each case, we include the full path
-# because it makes testing easier (specifically when modifying commands_dict
-# in test setup / teardown by adding info for a FakeCommand class defined
-# in a test-related module).
-#    Finally, we need to pass an iterable of pairs here rather than a dict
-# so that the ordering won't be lost when using Python 2.7.
-commands_dict: Dict[str, CommandInfo] = OrderedDict([
-    ('install', CommandInfo(
-        'pip._internal.commands.install', 'InstallCommand',
-        'Install packages.',
-    )),
-    ('download', CommandInfo(
-        'pip._internal.commands.download', 'DownloadCommand',
-        'Download packages.',
-    )),
-    ('uninstall', CommandInfo(
-        'pip._internal.commands.uninstall', 'UninstallCommand',
-        'Uninstall packages.',
-    )),
-    ('freeze', CommandInfo(
-        'pip._internal.commands.freeze', 'FreezeCommand',
-        'Output installed packages in requirements format.',
-    )),
-    ('list', CommandInfo(
-        'pip._internal.commands.list', 'ListCommand',
-        'List installed packages.',
-    )),
-    ('show', CommandInfo(
-        'pip._internal.commands.show', 'ShowCommand',
-        'Show information about installed packages.',
-    )),
-    ('check', CommandInfo(
-        'pip._internal.commands.check', 'CheckCommand',
-        'Verify installed packages have compatible dependencies.',
-    )),
-    ('config', CommandInfo(
-        'pip._internal.commands.configuration', 'ConfigurationCommand',
-        'Manage local and global configuration.',
-    )),
-    ('search', CommandInfo(
-        'pip._internal.commands.search', 'SearchCommand',
-        'Search PyPI for packages.',
-    )),
-    ('cache', CommandInfo(
-        'pip._internal.commands.cache', 'CacheCommand',
+# This dictionary does a bunch of heavy lifting for help output:
+# - Enables avoiding additional (costly) imports for presenting `--help`.
+# - The ordering matters for help display.
+#
+# Even though the module path starts with the same "pip._internal.commands"
+# prefix, the full path makes testing easier (specifically when modifying
+# `commands_dict` in test setup / teardown).
+commands_dict: Dict[str, CommandInfo] = {
+    "install": CommandInfo(
+        "pip._internal.commands.install",
+        "InstallCommand",
+        "Install packages.",
+    ),
+    "download": CommandInfo(
+        "pip._internal.commands.download",
+        "DownloadCommand",
+        "Download packages.",
+    ),
+    "uninstall": CommandInfo(
+        "pip._internal.commands.uninstall",
+        "UninstallCommand",
+        "Uninstall packages.",
+    ),
+    "freeze": CommandInfo(
+        "pip._internal.commands.freeze",
+        "FreezeCommand",
+        "Output installed packages in requirements format.",
+    ),
+    "inspect": CommandInfo(
+        "pip._internal.commands.inspect",
+        "InspectCommand",
+        "Inspect the python environment.",
+    ),
+    "list": CommandInfo(
+        "pip._internal.commands.list",
+        "ListCommand",
+        "List installed packages.",
+    ),
+    "show": CommandInfo(
+        "pip._internal.commands.show",
+        "ShowCommand",
+        "Show information about installed packages.",
+    ),
+    "check": CommandInfo(
+        "pip._internal.commands.check",
+        "CheckCommand",
+        "Verify installed packages have compatible dependencies.",
+    ),
+    "config": CommandInfo(
+        "pip._internal.commands.configuration",
+        "ConfigurationCommand",
+        "Manage local and global configuration.",
+    ),
+    "search": CommandInfo(
+        "pip._internal.commands.search",
+        "SearchCommand",
+        "Search PyPI for packages.",
+    ),
+    "cache": CommandInfo(
+        "pip._internal.commands.cache",
+        "CacheCommand",
         "Inspect and manage pip's wheel cache.",
-    )),
-    ('index', CommandInfo(
-        'pip._internal.commands.index', 'IndexCommand',
+    ),
+    "index": CommandInfo(
+        "pip._internal.commands.index",
+        "IndexCommand",
         "Inspect information available from package indexes.",
-    )),
-    ('wheel', CommandInfo(
-        'pip._internal.commands.wheel', 'WheelCommand',
-        'Build wheels from your requirements.',
-    )),
-    ('hash', CommandInfo(
-        'pip._internal.commands.hash', 'HashCommand',
-        'Compute hashes of package archives.',
-    )),
-    ('completion', CommandInfo(
-        'pip._internal.commands.completion', 'CompletionCommand',
-        'A helper command used for command completion.',
-    )),
-    ('debug', CommandInfo(
-        'pip._internal.commands.debug', 'DebugCommand',
-        'Show information useful for debugging.',
-    )),
-    ('help', CommandInfo(
-        'pip._internal.commands.help', 'HelpCommand',
-        'Show help for commands.',
-    )),
-])
+    ),
+    "wheel": CommandInfo(
+        "pip._internal.commands.wheel",
+        "WheelCommand",
+        "Build wheels from your requirements.",
+    ),
+    "hash": CommandInfo(
+        "pip._internal.commands.hash",
+        "HashCommand",
+        "Compute hashes of package archives.",
+    ),
+    "completion": CommandInfo(
+        "pip._internal.commands.completion",
+        "CompletionCommand",
+        "A helper command used for command completion.",
+    ),
+    "debug": CommandInfo(
+        "pip._internal.commands.debug",
+        "DebugCommand",
+        "Show information useful for debugging.",
+    ),
+    "help": CommandInfo(
+        "pip._internal.commands.help",
+        "HelpCommand",
+        "Show help for commands.",
+    ),
+}
 
 
 def create_command(name: str, **kwargs: Any) -> Command:

venv/Lib/site-packages/pip/_internal/commands/cache.py

@@ -37,19 +37,18 @@ class CacheCommand(Command):
     """
 
     def add_options(self) -> None:
-
         self.cmd_opts.add_option(
-            '--format',
-            action='store',
-            dest='list_format',
+            "--format",
+            action="store",
+            dest="list_format",
             default="human",
-            choices=('human', 'abspath'),
-            help="Select the output format among: human (default) or abspath"
+            choices=("human", "abspath"),
+            help="Select the output format among: human (default) or abspath",
         )
 
         self.parser.insert_option_group(0, self.cmd_opts)
 
-    def run(self, options: Values, args: List[Any]) -> int:
+    def run(self, options: Values, args: List[str]) -> int:
         handlers = {
             "dir": self.get_cache_dir,
             "info": self.get_cache_info,
@@ -59,8 +58,7 @@ class CacheCommand(Command):
         }
 
         if not options.cache_dir:
-            logger.error("pip cache commands can not "
-                         "function since cache is disabled.")
+            logger.error("pip cache commands can not function since cache is disabled.")
             return ERROR
 
         # Determine action
@@ -84,69 +82,73 @@ class CacheCommand(Command):
 
     def get_cache_dir(self, options: Values, args: List[Any]) -> None:
         if args:
-            raise CommandError('Too many arguments')
+            raise CommandError("Too many arguments")
 
         logger.info(options.cache_dir)
 
     def get_cache_info(self, options: Values, args: List[Any]) -> None:
         if args:
-            raise CommandError('Too many arguments')
+            raise CommandError("Too many arguments")
 
         num_http_files = len(self._find_http_files(options))
-        num_packages = len(self._find_wheels(options, '*'))
+        num_packages = len(self._find_wheels(options, "*"))
 
-        http_cache_location = self._cache_dir(options, 'http')
-        wheels_cache_location = self._cache_dir(options, 'wheels')
+        http_cache_location = self._cache_dir(options, "http")
+        wheels_cache_location = self._cache_dir(options, "wheels")
         http_cache_size = filesystem.format_directory_size(http_cache_location)
-        wheels_cache_size = filesystem.format_directory_size(
-            wheels_cache_location
-        )
+        wheels_cache_size = filesystem.format_directory_size(wheels_cache_location)
 
-        message = textwrap.dedent("""
-            Package index page cache location: {http_cache_location}
-            Package index page cache size: {http_cache_size}
-            Number of HTTP files: {num_http_files}
-            Wheels location: {wheels_cache_location}
-            Wheels size: {wheels_cache_size}
-            Number of wheels: {package_count}
-        """).format(
-            http_cache_location=http_cache_location,
-            http_cache_size=http_cache_size,
-            num_http_files=num_http_files,
-            wheels_cache_location=wheels_cache_location,
-            package_count=num_packages,
-            wheels_cache_size=wheels_cache_size,
-        ).strip()
+        message = (
+            textwrap.dedent(
+                """
+                    Package index page cache location: {http_cache_location}
+                    Package index page cache size: {http_cache_size}
+                    Number of HTTP files: {num_http_files}
+                    Locally built wheels location: {wheels_cache_location}
+                    Locally built wheels size: {wheels_cache_size}
+                    Number of locally built wheels: {package_count}
+                """
+            )
+            .format(
+                http_cache_location=http_cache_location,
+                http_cache_size=http_cache_size,
+                num_http_files=num_http_files,
+                wheels_cache_location=wheels_cache_location,
+                package_count=num_packages,
+                wheels_cache_size=wheels_cache_size,
+            )
+            .strip()
+        )
 
         logger.info(message)
 
     def list_cache_items(self, options: Values, args: List[Any]) -> None:
         if len(args) > 1:
-            raise CommandError('Too many arguments')
+            raise CommandError("Too many arguments")
 
         if args:
             pattern = args[0]
         else:
-            pattern = '*'
+            pattern = "*"
 
         files = self._find_wheels(options, pattern)
-        if options.list_format == 'human':
+        if options.list_format == "human":
             self.format_for_human(files)
         else:
             self.format_for_abspath(files)
 
     def format_for_human(self, files: List[str]) -> None:
         if not files:
-            logger.info('Nothing cached.')
+            logger.info("No locally built wheels cached.")
             return
 
         results = []
         for filename in files:
             wheel = os.path.basename(filename)
             size = filesystem.format_file_size(filename)
-            results.append(f' - {wheel} ({size})')
-        logger.info('Cache contents:\n')
-        logger.info('\n'.join(sorted(results)))
+            results.append(f" - {wheel} ({size})")
+        logger.info("Cache contents:\n")
+        logger.info("\n".join(sorted(results)))
 
     def format_for_abspath(self, files: List[str]) -> None:
         if not files:
@@ -156,23 +158,27 @@ class CacheCommand(Command):
         for filename in files:
             results.append(filename)
 
-        logger.info('\n'.join(sorted(results)))
+        logger.info("\n".join(sorted(results)))
 
     def remove_cache_items(self, options: Values, args: List[Any]) -> None:
         if len(args) > 1:
-            raise CommandError('Too many arguments')
+            raise CommandError("Too many arguments")
 
         if not args:
-            raise CommandError('Please provide a pattern')
+            raise CommandError("Please provide a pattern")
 
         files = self._find_wheels(options, args[0])
 
-        # Only fetch http files if no specific pattern given
-        if args[0] == '*':
+        no_matching_msg = "No matching packages"
+        if args[0] == "*":
+            # Only fetch http files if no specific pattern given
             files += self._find_http_files(options)
+        else:
+            # Add the pattern to the log message
+            no_matching_msg += ' for pattern "{}"'.format(args[0])
 
         if not files:
-            raise CommandError('No matching packages')
+            logger.warning(no_matching_msg)
 
         for filename in files:
             os.unlink(filename)
@@ -181,19 +187,19 @@ class CacheCommand(Command):
 
     def purge_cache(self, options: Values, args: List[Any]) -> None:
         if args:
-            raise CommandError('Too many arguments')
+            raise CommandError("Too many arguments")
 
-        return self.remove_cache_items(options, ['*'])
+        return self.remove_cache_items(options, ["*"])
 
     def _cache_dir(self, options: Values, subdir: str) -> str:
         return os.path.join(options.cache_dir, subdir)
 
     def _find_http_files(self, options: Values) -> List[str]:
-        http_dir = self._cache_dir(options, 'http')
-        return filesystem.find_files(http_dir, '*')
+        http_dir = self._cache_dir(options, "http")
+        return filesystem.find_files(http_dir, "*")
 
     def _find_wheels(self, options: Values, pattern: str) -> List[str]:
-        wheel_dir = self._cache_dir(options, 'wheels')
+        wheel_dir = self._cache_dir(options, "wheels")
 
         # The wheel filename format, as specified in PEP 427, is:
         #     {distribution}-{version}(-{build})?-{python}-{abi}-{platform}.whl

venv/Lib/site-packages/pip/_internal/commands/check.py

@@ -1,6 +1,6 @@
 import logging
 from optparse import Values
-from typing import Any, List
+from typing import List
 
 from pip._internal.cli.base_command import Command
 from pip._internal.cli.status_codes import ERROR, SUCCESS
@@ -19,8 +19,7 @@ class CheckCommand(Command):
     usage = """
       %prog [options]"""
 
-    def run(self, options: Values, args: List[Any]) -> int:
-
+    def run(self, options: Values, args: List[str]) -> int:
         package_set, parsing_probs = create_package_set_from_installed()
         missing, conflicting = check_package_set(package_set)
 
@@ -29,7 +28,9 @@ class CheckCommand(Command):
             for dependency in missing[project_name]:
                 write_output(
                     "%s %s requires %s, which is not installed.",
-                    project_name, version, dependency[0],
+                    project_name,
+                    version,
+                    dependency[0],
                 )
 
         for project_name in conflicting:
@@ -37,7 +38,11 @@ class CheckCommand(Command):
             for dep_name, dep_version, req in conflicting[project_name]:
                 write_output(
                     "%s %s has requirement %s, but you have %s %s.",
-                    project_name, version, req, dep_name, dep_version,
+                    project_name,
+                    version,
+                    req,
+                    dep_name,
+                    dep_version,
                 )
 
         if missing or conflicting or parsing_probs:

venv/Lib/site-packages/pip/_internal/commands/completion.py

@@ -12,7 +12,7 @@ BASE_COMPLETION = """
 """
 
 COMPLETION_SCRIPTS = {
-    'bash': """
+    "bash": """
         _pip_completion()
         {{
             COMPREPLY=( $( COMP_WORDS="${{COMP_WORDS[*]}}" \\
@@ -21,7 +21,7 @@ COMPLETION_SCRIPTS = {
         }}
         complete -o default -F _pip_completion {prog}
     """,
-    'zsh': """
+    "zsh": """
         function _pip_completion {{
           local words cword
           read -Ac words
@@ -32,7 +32,7 @@ COMPLETION_SCRIPTS = {
         }}
         compctl -K _pip_completion {prog}
     """,
-    'fish': """
+    "fish": """
         function __fish_complete_pip
             set -lx COMP_WORDS (commandline -o) ""
             set -lx COMP_CWORD ( \\
@@ -43,6 +43,28 @@ COMPLETION_SCRIPTS = {
         end
         complete -fa "(__fish_complete_pip)" -c {prog}
     """,
+    "powershell": """
+        if ((Test-Path Function:\\TabExpansion) -and -not `
+            (Test-Path Function:\\_pip_completeBackup)) {{
+            Rename-Item Function:\\TabExpansion _pip_completeBackup
+        }}
+        function TabExpansion($line, $lastWord) {{
+            $lastBlock = [regex]::Split($line, '[|;]')[-1].TrimStart()
+            if ($lastBlock.StartsWith("{prog} ")) {{
+                $Env:COMP_WORDS=$lastBlock
+                $Env:COMP_CWORD=$lastBlock.Split().Length - 1
+                $Env:PIP_AUTO_COMPLETE=1
+                (& {prog}).Split()
+                Remove-Item Env:COMP_WORDS
+                Remove-Item Env:COMP_CWORD
+                Remove-Item Env:PIP_AUTO_COMPLETE
+            }}
+            elseif (Test-Path Function:\\_pip_completeBackup) {{
+                # Fall back on existing tab expansion
+                _pip_completeBackup $line $lastWord
+            }}
+        }}
+    """,
 }
 
 
@@ -53,39 +75,52 @@ class CompletionCommand(Command):
 
     def add_options(self) -> None:
         self.cmd_opts.add_option(
-            '--bash', '-b',
-            action='store_const',
-            const='bash',
-            dest='shell',
-            help='Emit completion code for bash')
+            "--bash",
+            "-b",
+            action="store_const",
+            const="bash",
+            dest="shell",
+            help="Emit completion code for bash",
+        )
         self.cmd_opts.add_option(
-            '--zsh', '-z',
-            action='store_const',
-            const='zsh',
-            dest='shell',
-            help='Emit completion code for zsh')
+            "--zsh",
+            "-z",
+            action="store_const",
+            const="zsh",
+            dest="shell",
+            help="Emit completion code for zsh",
+        )
         self.cmd_opts.add_option(
-            '--fish', '-f',
-            action='store_const',
-            const='fish',
-            dest='shell',
-            help='Emit completion code for fish')
+            "--fish",
+            "-f",
+            action="store_const",
+            const="fish",
+            dest="shell",
+            help="Emit completion code for fish",
+        )
+        self.cmd_opts.add_option(
+            "--powershell",
+            "-p",
+            action="store_const",
+            const="powershell",
+            dest="shell",
+            help="Emit completion code for powershell",
+        )
 
         self.parser.insert_option_group(0, self.cmd_opts)
 
     def run(self, options: Values, args: List[str]) -> int:
         """Prints the completion code of the given shell"""
         shells = COMPLETION_SCRIPTS.keys()
-        shell_options = ['--' + shell for shell in sorted(shells)]
+        shell_options = ["--" + shell for shell in sorted(shells)]
         if options.shell in shells:
             script = textwrap.dedent(
-                COMPLETION_SCRIPTS.get(options.shell, '').format(
-                    prog=get_prog())
+                COMPLETION_SCRIPTS.get(options.shell, "").format(prog=get_prog())
             )
             print(BASE_COMPLETION.format(script=script, shell=options.shell))
             return SUCCESS
         else:
             sys.stderr.write(
-                'ERROR: You must pass {}\n' .format(' or '.join(shell_options))
+                "ERROR: You must pass {}\n".format(" or ".join(shell_options))
             )
             return SUCCESS

venv/Lib/site-packages/pip/_internal/commands/configuration.py

@@ -27,14 +27,20 @@ class ConfigurationCommand(Command):
 
     - list: List the active configuration (or from the file specified)
     - edit: Edit the configuration file in an editor
-    - get: Get the value associated with name
-    - set: Set the name=value
-    - unset: Unset the value associated with name
+    - get: Get the value associated with command.option
+    - set: Set the command.option=value
+    - unset: Unset the value associated with command.option
     - debug: List the configuration files and values defined under them
 
+    Configuration keys should be dot separated command and option name,
+    with the special prefix "global" affecting any command. For example,
+    "pip config set global.index-url https://example.org/" would configure
+    the index url for all commands, but "pip config set download.timeout 10"
+    would configure a 10 second timeout only for "pip download" commands.
+
     If none of --user, --global and --site are passed, a virtual
     environment configuration file is used if one is active and the file
-    exists. Otherwise, all modifications happen on the to the user file by
+    exists. Otherwise, all modifications happen to the user file by
     default.
     """
 
@@ -43,46 +49,46 @@ class ConfigurationCommand(Command):
         %prog [<file-option>] list
         %prog [<file-option>] [--editor <editor-path>] edit
 
-        %prog [<file-option>] get name
-        %prog [<file-option>] set name value
-        %prog [<file-option>] unset name
+        %prog [<file-option>] get command.option
+        %prog [<file-option>] set command.option value
+        %prog [<file-option>] unset command.option
         %prog [<file-option>] debug
     """
 
     def add_options(self) -> None:
         self.cmd_opts.add_option(
-            '--editor',
-            dest='editor',
-            action='store',
+            "--editor",
+            dest="editor",
+            action="store",
             default=None,
             help=(
-                'Editor to use to edit the file. Uses VISUAL or EDITOR '
-                'environment variables if not provided.'
-            )
+                "Editor to use to edit the file. Uses VISUAL or EDITOR "
+                "environment variables if not provided."
+            ),
         )
 
         self.cmd_opts.add_option(
-            '--global',
-            dest='global_file',
-            action='store_true',
+            "--global",
+            dest="global_file",
+            action="store_true",
             default=False,
-            help='Use the system-wide configuration file only'
+            help="Use the system-wide configuration file only",
         )
 
         self.cmd_opts.add_option(
-            '--user',
-            dest='user_file',
-            action='store_true',
+            "--user",
+            dest="user_file",
+            action="store_true",
             default=False,
-            help='Use the user configuration file only'
+            help="Use the user configuration file only",
         )
 
         self.cmd_opts.add_option(
-            '--site',
-            dest='site_file',
-            action='store_true',
+            "--site",
+            dest="site_file",
+            action="store_true",
             default=False,
-            help='Use the current environment configuration file only'
+            help="Use the current environment configuration file only",
         )
 
         self.parser.insert_option_group(0, self.cmd_opts)
@@ -133,11 +139,15 @@ class ConfigurationCommand(Command):
         return SUCCESS
 
     def _determine_file(self, options: Values, need_value: bool) -> Optional[Kind]:
-        file_options = [key for key, value in (
-            (kinds.USER, options.user_file),
-            (kinds.GLOBAL, options.global_file),
-            (kinds.SITE, options.site_file),
-        ) if value]
+        file_options = [
+            key
+            for key, value in (
+                (kinds.USER, options.user_file),
+                (kinds.GLOBAL, options.global_file),
+                (kinds.SITE, options.site_file),
+            )
+            if value
+        ]
 
         if not file_options:
             if not need_value:
@@ -194,24 +204,22 @@ class ConfigurationCommand(Command):
             for fname in files:
                 with indent_log():
                     file_exists = os.path.exists(fname)
-                    write_output("%s, exists: %r",
-                                 fname, file_exists)
+                    write_output("%s, exists: %r", fname, file_exists)
                     if file_exists:
                         self.print_config_file_values(variant)
 
     def print_config_file_values(self, variant: Kind) -> None:
         """Get key-value pairs from the file of a variant"""
-        for name, value in self.configuration.\
-                get_values_in_config(variant).items():
+        for name, value in self.configuration.get_values_in_config(variant).items():
             with indent_log():
                 write_output("%s: %s", name, value)
 
     def print_env_var_values(self) -> None:
         """Get key-values pairs present as environment variables"""
-        write_output("%s:", 'env_var')
+        write_output("%s:", "env_var")
         with indent_log():
             for key, value in sorted(self.configuration.get_environ_vars()):
-                env_var = f'PIP_{key.upper()}'
+                env_var = f"PIP_{key.upper()}"
                 write_output("%s=%r", env_var, value)
 
     def open_in_editor(self, options: Values, args: List[str]) -> None:
@@ -220,21 +228,29 @@ class ConfigurationCommand(Command):
         fname = self.configuration.get_file_to_edit()
         if fname is None:
             raise PipError("Could not determine appropriate file.")
+        elif '"' in fname:
+            # This shouldn't happen, unless we see a username like that.
+            # If that happens, we'd appreciate a pull request fixing this.
+            raise PipError(
+                f'Can not open an editor for a file name containing "\n{fname}'
+            )
 
         try:
-            subprocess.check_call([editor, fname])
+            subprocess.check_call(f'{editor} "{fname}"', shell=True)
+        except FileNotFoundError as e:
+            if not e.filename:
+                e.filename = editor
+            raise
         except subprocess.CalledProcessError as e:
             raise PipError(
-                "Editor Subprocess exited with exit code {}"
-                .format(e.returncode)
+                "Editor Subprocess exited with exit code {}".format(e.returncode)
             )
 
     def _get_n_args(self, args: List[str], example: str, n: int) -> Any:
-        """Helper to make sure the command got the right number of arguments
-        """
+        """Helper to make sure the command got the right number of arguments"""
         if len(args) != n:
             msg = (
-                'Got unexpected number of arguments, expected {}. '
+                "Got unexpected number of arguments, expected {}. "
                 '(example: "{} config {}")'
             ).format(n, get_prog(), example)
             raise PipError(msg)

venv/Lib/site-packages/pip/_internal/commands/debug.py

@@ -1,3 +1,4 @@
+import importlib.resources
 import locale
 import logging
 import os
@@ -10,7 +11,6 @@ import pip._vendor
 from pip._vendor.certifi import where
 from pip._vendor.packaging.version import parse as parse_version
 
-from pip import __file__ as pip_location
 from pip._internal.cli import cmdoptions
 from pip._internal.cli.base_command import Command
 from pip._internal.cli.cmdoptions import make_target_python
@@ -24,55 +24,46 @@ logger = logging.getLogger(__name__)
 
 
 def show_value(name: str, value: Any) -> None:
-    logger.info('%s: %s', name, value)
+    logger.info("%s: %s", name, value)
 
 
 def show_sys_implementation() -> None:
-    logger.info('sys.implementation:')
+    logger.info("sys.implementation:")
     implementation_name = sys.implementation.name
     with indent_log():
-        show_value('name', implementation_name)
+        show_value("name", implementation_name)
 
 
 def create_vendor_txt_map() -> Dict[str, str]:
-    vendor_txt_path = os.path.join(
-        os.path.dirname(pip_location),
-        '_vendor',
-        'vendor.txt'
-    )
-
-    with open(vendor_txt_path) as f:
+    with importlib.resources.open_text("pip._vendor", "vendor.txt") as f:
         # Purge non version specifying lines.
         # Also, remove any space prefix or suffixes (including comments).
-        lines = [line.strip().split(' ', 1)[0]
-                 for line in f.readlines() if '==' in line]
+        lines = [
+            line.strip().split(" ", 1)[0] for line in f.readlines() if "==" in line
+        ]
 
     # Transform into "module" -> version dict.
-    return dict(line.split('==', 1) for line in lines)  # type: ignore
+    return dict(line.split("==", 1) for line in lines)
 
 
 def get_module_from_module_name(module_name: str) -> ModuleType:
     # Module name can be uppercase in vendor.txt for some reason...
-    module_name = module_name.lower()
+    module_name = module_name.lower().replace("-", "_")
     # PATCH: setuptools is actually only pkg_resources.
-    if module_name == 'setuptools':
-        module_name = 'pkg_resources'
+    if module_name == "setuptools":
+        module_name = "pkg_resources"
 
-    __import__(
-        f'pip._vendor.{module_name}',
-        globals(),
-        locals(),
-        level=0
-    )
+    __import__(f"pip._vendor.{module_name}", globals(), locals(), level=0)
     return getattr(pip._vendor, module_name)
 
 
 def get_vendor_version_from_module(module_name: str) -> Optional[str]:
     module = get_module_from_module_name(module_name)
-    version = getattr(module, '__version__', None)
+    version = getattr(module, "__version__", None)
 
     if not version:
         # Try to find version in debundled module info.
+        assert module.__file__ is not None
         env = get_environment([os.path.dirname(module.__file__)])
         dist = env.get_distribution(module_name)
         if dist:
@@ -86,20 +77,24 @@ def show_actual_vendor_versions(vendor_txt_versions: Dict[str, str]) -> None:
     a conflict or if the actual version could not be imported.
     """
     for module_name, expected_version in vendor_txt_versions.items():
-        extra_message = ''
+        extra_message = ""
         actual_version = get_vendor_version_from_module(module_name)
         if not actual_version:
-            extra_message = ' (Unable to locate actual module version, using'\
-                            ' vendor.txt specified version)'
+            extra_message = (
+                " (Unable to locate actual module version, using"
+                " vendor.txt specified version)"
+            )
             actual_version = expected_version
         elif parse_version(actual_version) != parse_version(expected_version):
-            extra_message = ' (CONFLICT: vendor.txt suggests version should'\
-                            ' be {})'.format(expected_version)
-        logger.info('%s==%s%s', module_name, actual_version, extra_message)
+            extra_message = (
+                " (CONFLICT: vendor.txt suggests version should"
+                " be {})".format(expected_version)
+            )
+        logger.info("%s==%s%s", module_name, actual_version, extra_message)
 
 
 def show_vendor_versions() -> None:
-    logger.info('vendored library versions:')
+    logger.info("vendored library versions:")
 
     vendor_txt_versions = create_vendor_txt_map()
     with indent_log():
@@ -114,11 +109,11 @@ def show_tags(options: Values) -> None:
 
     # Display the target options that were explicitly provided.
     formatted_target = target_python.format_given()
-    suffix = ''
+    suffix = ""
     if formatted_target:
-        suffix = f' (target: {formatted_target})'
+        suffix = f" (target: {formatted_target})"
 
-    msg = 'Compatible tags: {}{}'.format(len(tags), suffix)
+    msg = "Compatible tags: {}{}".format(len(tags), suffix)
     logger.info(msg)
 
     if options.verbose < 1 and len(tags) > tag_limit:
@@ -133,8 +128,7 @@ def show_tags(options: Values) -> None:
 
         if tags_limited:
             msg = (
-                '...\n'
-                '[First {tag_limit} tags shown. Pass --verbose to show all.]'
+                "...\n[First {tag_limit} tags shown. Pass --verbose to show all.]"
             ).format(tag_limit=tag_limit)
             logger.info(msg)
 
@@ -142,20 +136,20 @@ def show_tags(options: Values) -> None:
 def ca_bundle_info(config: Configuration) -> str:
     levels = set()
     for key, _ in config.items():
-        levels.add(key.split('.')[0])
+        levels.add(key.split(".")[0])
 
     if not levels:
         return "Not specified"
 
-    levels_that_override_global = ['install', 'wheel', 'download']
+    levels_that_override_global = ["install", "wheel", "download"]
     global_overriding_level = [
         level for level in levels if level in levels_that_override_global
     ]
     if not global_overriding_level:
-        return 'global'
+        return "global"
 
-    if 'global' in levels:
-        levels.remove('global')
+    if "global" in levels:
+        levels.remove("global")
     return ", ".join(levels)
 
 
@@ -180,20 +174,21 @@ class DebugCommand(Command):
             "details, since the output and options of this command may "
             "change without notice."
         )
-        show_value('pip version', get_pip_version())
-        show_value('sys.version', sys.version)
-        show_value('sys.executable', sys.executable)
-        show_value('sys.getdefaultencoding', sys.getdefaultencoding())
-        show_value('sys.getfilesystemencoding', sys.getfilesystemencoding())
+        show_value("pip version", get_pip_version())
+        show_value("sys.version", sys.version)
+        show_value("sys.executable", sys.executable)
+        show_value("sys.getdefaultencoding", sys.getdefaultencoding())
+        show_value("sys.getfilesystemencoding", sys.getfilesystemencoding())
         show_value(
-            'locale.getpreferredencoding', locale.getpreferredencoding(),
+            "locale.getpreferredencoding",
+            locale.getpreferredencoding(),
         )
-        show_value('sys.platform', sys.platform)
+        show_value("sys.platform", sys.platform)
         show_sys_implementation()
 
         show_value("'cert' config value", ca_bundle_info(self.parser.config))
-        show_value("REQUESTS_CA_BUNDLE", os.environ.get('REQUESTS_CA_BUNDLE'))
-        show_value("CURL_CA_BUNDLE", os.environ.get('CURL_CA_BUNDLE'))
+        show_value("REQUESTS_CA_BUNDLE", os.environ.get("REQUESTS_CA_BUNDLE"))
+        show_value("CURL_CA_BUNDLE", os.environ.get("CURL_CA_BUNDLE"))
         show_value("pip._vendor.certifi.where()", where())
         show_value("pip._vendor.DEBUNDLED", pip._vendor.DEBUNDLED)
 

venv/Lib/site-packages/pip/_internal/commands/download.py

@@ -7,7 +7,8 @@ from pip._internal.cli import cmdoptions
 from pip._internal.cli.cmdoptions import make_target_python
 from pip._internal.cli.req_command import RequirementCommand, with_cleanup
 from pip._internal.cli.status_codes import SUCCESS
-from pip._internal.req.req_tracker import get_requirement_tracker
+from pip._internal.operations.build.build_tracker import get_build_tracker
+from pip._internal.req.req_install import check_legacy_setup_py_options
 from pip._internal.utils.misc import ensure_dir, normalize_path, write_output
 from pip._internal.utils.temp_dir import TempDirectory
 
@@ -37,7 +38,6 @@ class DownloadCommand(RequirementCommand):
     def add_options(self) -> None:
         self.cmd_opts.add_option(cmdoptions.constraints())
         self.cmd_opts.add_option(cmdoptions.requirements())
-        self.cmd_opts.add_option(cmdoptions.build_dir())
         self.cmd_opts.add_option(cmdoptions.no_deps())
         self.cmd_opts.add_option(cmdoptions.global_options())
         self.cmd_opts.add_option(cmdoptions.no_binary())
@@ -50,14 +50,18 @@ class DownloadCommand(RequirementCommand):
         self.cmd_opts.add_option(cmdoptions.no_build_isolation())
         self.cmd_opts.add_option(cmdoptions.use_pep517())
         self.cmd_opts.add_option(cmdoptions.no_use_pep517())
+        self.cmd_opts.add_option(cmdoptions.check_build_deps())
         self.cmd_opts.add_option(cmdoptions.ignore_requires_python())
 
         self.cmd_opts.add_option(
-            '-d', '--dest', '--destination-dir', '--destination-directory',
-            dest='download_dir',
-            metavar='dir',
+            "-d",
+            "--dest",
+            "--destination-dir",
+            "--destination-directory",
+            dest="download_dir",
+            metavar="dir",
             default=os.curdir,
-            help=("Download packages into <dir>."),
+            help="Download packages into <dir>.",
         )
 
         cmdoptions.add_target_python_options(self.cmd_opts)
@@ -72,7 +76,6 @@ class DownloadCommand(RequirementCommand):
 
     @with_cleanup
     def run(self, options: Values, args: List[str]) -> int:
-
         options.ignore_installed = True
         # editable doesn't really make sense for `pip download`, but the bowels
         # of the RequirementSet code require that property.
@@ -93,7 +96,7 @@ class DownloadCommand(RequirementCommand):
             ignore_requires_python=options.ignore_requires_python,
         )
 
-        req_tracker = self.enter_context(get_requirement_tracker())
+        build_tracker = self.enter_context(get_build_tracker())
 
         directory = TempDirectory(
             delete=not options.no_clean,
@@ -102,15 +105,17 @@ class DownloadCommand(RequirementCommand):
         )
 
         reqs = self.get_requirements(args, options, finder, session)
+        check_legacy_setup_py_options(options, reqs)
 
         preparer = self.make_requirement_preparer(
             temp_build_dir=directory,
             options=options,
-            req_tracker=req_tracker,
+            build_tracker=build_tracker,
             session=session,
             finder=finder,
             download_dir=options.download_dir,
             use_user_site=False,
+            verbosity=self.verbosity,
         )
 
         resolver = self.make_resolver(
@@ -118,14 +123,13 @@ class DownloadCommand(RequirementCommand):
             finder=finder,
             options=options,
             ignore_requires_python=options.ignore_requires_python,
+            use_pep517=options.use_pep517,
             py_version_info=options.python_version,
         )
 
         self.trace_basic_info(finder)
 
-        requirement_set = resolver.resolve(
-            reqs, check_supported_wheels=True
-        )
+        requirement_set = resolver.resolve(reqs, check_supported_wheels=True)
 
         downloaded: List[str] = []
         for req in requirement_set.requirements.values():
@@ -134,6 +138,6 @@ class DownloadCommand(RequirementCommand):
                 preparer.save_linked_requirement(req)
                 downloaded.append(req.name)
         if downloaded:
-            write_output('Successfully downloaded %s', ' '.join(downloaded))
+            write_output("Successfully downloaded %s", " ".join(downloaded))
 
         return SUCCESS

venv/Lib/site-packages/pip/_internal/commands/freeze.py

@@ -8,7 +8,7 @@ from pip._internal.cli.status_codes import SUCCESS
 from pip._internal.operations.freeze import freeze
 from pip._internal.utils.compat import stdlib_pkgs
 
-DEV_PKGS = {'pip', 'setuptools', 'distribute', 'wheel'}
+DEV_PKGS = {"pip", "setuptools", "distribute", "wheel"}
 
 
 class FreezeCommand(Command):
@@ -24,39 +24,52 @@ class FreezeCommand(Command):
 
     def add_options(self) -> None:
         self.cmd_opts.add_option(
-            '-r', '--requirement',
-            dest='requirements',
-            action='append',
+            "-r",
+            "--requirement",
+            dest="requirements",
+            action="append",
             default=[],
-            metavar='file',
-            help="Use the order in the given requirements file and its "
-                 "comments when generating output. This option can be "
-                 "used multiple times.")
+            metavar="file",
+            help=(
+                "Use the order in the given requirements file and its "
+                "comments when generating output. This option can be "
+                "used multiple times."
+            ),
+        )
         self.cmd_opts.add_option(
-            '-l', '--local',
-            dest='local',
-            action='store_true',
+            "-l",
+            "--local",
+            dest="local",
+            action="store_true",
             default=False,
-            help='If in a virtualenv that has global access, do not output '
-                 'globally-installed packages.')
+            help=(
+                "If in a virtualenv that has global access, do not output "
+                "globally-installed packages."
+            ),
+        )
         self.cmd_opts.add_option(
-            '--user',
-            dest='user',
-            action='store_true',
+            "--user",
+            dest="user",
+            action="store_true",
             default=False,
-            help='Only output packages installed in user-site.')
+            help="Only output packages installed in user-site.",
+        )
         self.cmd_opts.add_option(cmdoptions.list_path())
         self.cmd_opts.add_option(
-            '--all',
-            dest='freeze_all',
-            action='store_true',
-            help='Do not skip these packages in the output:'
-                 ' {}'.format(', '.join(DEV_PKGS)))
+            "--all",
+            dest="freeze_all",
+            action="store_true",
+            help=(
+                "Do not skip these packages in the output:"
+                " {}".format(", ".join(DEV_PKGS))
+            ),
+        )
         self.cmd_opts.add_option(
-            '--exclude-editable',
-            dest='exclude_editable',
-            action='store_true',
-            help='Exclude editable package from output.')
+            "--exclude-editable",
+            dest="exclude_editable",
+            action="store_true",
+            help="Exclude editable package from output.",
+        )
         self.cmd_opts.add_option(cmdoptions.list_exclude())
 
         self.parser.insert_option_group(0, self.cmd_opts)
@@ -80,5 +93,5 @@ class FreezeCommand(Command):
             skip=skip,
             exclude_editable=options.exclude_editable,
         ):
-            sys.stdout.write(line + '\n')
+            sys.stdout.write(line + "\n")
         return SUCCESS

venv/Lib/site-packages/pip/_internal/commands/hash.py

@@ -20,18 +20,21 @@ class HashCommand(Command):
     installs.
     """
 
-    usage = '%prog [options] <file> ...'
+    usage = "%prog [options] <file> ..."
     ignore_require_venv = True
 
     def add_options(self) -> None:
         self.cmd_opts.add_option(
-            '-a', '--algorithm',
-            dest='algorithm',
+            "-a",
+            "--algorithm",
+            dest="algorithm",
             choices=STRONG_HASHES,
-            action='store',
+            action="store",
             default=FAVORITE_HASH,
-            help='The hash algorithm to use: one of {}'.format(
-                 ', '.join(STRONG_HASHES)))
+            help="The hash algorithm to use: one of {}".format(
+                ", ".join(STRONG_HASHES)
+            ),
+        )
         self.parser.insert_option_group(0, self.cmd_opts)
 
     def run(self, options: Values, args: List[str]) -> int:
@@ -41,14 +44,15 @@ class HashCommand(Command):
 
         algorithm = options.algorithm
         for path in args:
-            write_output('%s:\n--hash=%s:%s',
-                         path, algorithm, _hash_of_file(path, algorithm))
+            write_output(
+                "%s:\n--hash=%s:%s", path, algorithm, _hash_of_file(path, algorithm)
+            )
         return SUCCESS
 
 
 def _hash_of_file(path: str, algorithm: str) -> str:
     """Return the hash digest of a file."""
-    with open(path, 'rb') as archive:
+    with open(path, "rb") as archive:
         hash = hashlib.new(algorithm)
         for chunk in read_chunks(archive):
             hash.update(chunk)

venv/Lib/site-packages/pip/_internal/commands/help.py

@@ -33,7 +33,7 @@ class HelpCommand(Command):
             if guess:
                 msg.append(f'maybe you meant "{guess}"')
 
-            raise CommandError(' - '.join(msg))
+            raise CommandError(" - ".join(msg))
 
         command = create_command(cmd_name)
         command.parser.print_help()

venv/Lib/site-packages/pip/_internal/commands/index.py

@@ -24,6 +24,7 @@ class IndexCommand(IndexGroupCommand):
     Inspect information available from package indexes.
     """
 
+    ignore_require_venv = True
     usage = """
         %prog versions <package>
     """
@@ -44,7 +45,7 @@ class IndexCommand(IndexGroupCommand):
         self.parser.insert_option_group(0, index_opts)
         self.parser.insert_option_group(0, self.cmd_opts)
 
-    def run(self, options: Values, args: List[Any]) -> int:
+    def run(self, options: Values, args: List[str]) -> int:
         handlers = {
             "versions": self.get_available_package_versions,
         }
@@ -101,7 +102,7 @@ class IndexCommand(IndexGroupCommand):
 
     def get_available_package_versions(self, options: Values, args: List[Any]) -> None:
         if len(args) != 1:
-            raise CommandError('You need to specify exactly one argument')
+            raise CommandError("You need to specify exactly one argument")
 
         target_python = cmdoptions.make_target_python(options)
         query = args[0]
@@ -115,25 +116,24 @@ class IndexCommand(IndexGroupCommand):
             )
 
             versions: Iterable[Union[LegacyVersion, Version]] = (
-                candidate.version
-                for candidate in finder.find_all_candidates(query)
+                candidate.version for candidate in finder.find_all_candidates(query)
             )
 
             if not options.pre:
                 # Remove prereleases
-                versions = (version for version in versions
-                            if not version.is_prerelease)
+                versions = (
+                    version for version in versions if not version.is_prerelease
+                )
             versions = set(versions)
 
             if not versions:
                 raise DistributionNotFound(
-                    'No matching distribution found for {}'.format(query))
+                    "No matching distribution found for {}".format(query)
+                )
 
-            formatted_versions = [str(ver) for ver in sorted(
-                versions, reverse=True)]
+            formatted_versions = [str(ver) for ver in sorted(versions, reverse=True)]
             latest = formatted_versions[0]
 
-        write_output('{} ({})'.format(query, latest))
-        write_output('Available versions: {}'.format(
-            ', '.join(formatted_versions)))
+        write_output("{} ({})".format(query, latest))
+        write_output("Available versions: {}".format(", ".join(formatted_versions)))
         print_dist_installation_info(query, latest)

venv/Lib/site-packages/pip/_internal/commands/install.py

@@ -1,12 +1,13 @@
 import errno
+import json
 import operator
 import os
 import shutil
 import site
 from optparse import SUPPRESS_HELP, Values
-from typing import Iterable, List, Optional
+from typing import List, Optional
 
-from pip._vendor.packaging.utils import canonicalize_name
+from pip._vendor.rich import print_json
 
 from pip._internal.cache import WheelCache
 from pip._internal.cli import cmdoptions
@@ -20,16 +21,19 @@ from pip._internal.cli.status_codes import ERROR, SUCCESS
 from pip._internal.exceptions import CommandError, InstallationError
 from pip._internal.locations import get_scheme
 from pip._internal.metadata import get_environment
-from pip._internal.models.format_control import FormatControl
+from pip._internal.models.installation_report import InstallationReport
+from pip._internal.operations.build.build_tracker import get_build_tracker
 from pip._internal.operations.check import ConflictDetails, check_install_conflicts
 from pip._internal.req import install_given_reqs
-from pip._internal.req.req_install import InstallRequirement
-from pip._internal.req.req_tracker import get_requirement_tracker
+from pip._internal.req.req_install import (
+    InstallRequirement,
+    check_legacy_setup_py_options,
+)
 from pip._internal.utils.compat import WINDOWS
-from pip._internal.utils.distutils_args import parse_distutils_args
 from pip._internal.utils.filesystem import test_writable_dir
 from pip._internal.utils.logging import getLogger
 from pip._internal.utils.misc import (
+    check_externally_managed,
     ensure_dir,
     get_pip_version,
     protect_pip_from_modification_on_windows,
@@ -40,24 +44,11 @@ from pip._internal.utils.virtualenv import (
     running_under_virtualenv,
     virtualenv_no_global,
 )
-from pip._internal.wheel_builder import (
-    BinaryAllowedPredicate,
-    build,
-    should_build_for_install_command,
-)
+from pip._internal.wheel_builder import build, should_build_for_install_command
 
 logger = getLogger(__name__)
 
 
-def get_check_binary_allowed(format_control: FormatControl) -> BinaryAllowedPredicate:
-    def check_binary_allowed(req: InstallRequirement) -> bool:
-        canonical_name = canonicalize_name(req.name or "")
-        allowed_formats = format_control.get_allowed_formats(canonical_name)
-        return "binary" in allowed_formats
-
-    return check_binary_allowed
-
-
 class InstallCommand(RequirementCommand):
     """
     Install packages from:
@@ -86,95 +77,129 @@ class InstallCommand(RequirementCommand):
 
         self.cmd_opts.add_option(cmdoptions.editable())
         self.cmd_opts.add_option(
-            '-t', '--target',
-            dest='target_dir',
-            metavar='dir',
+            "--dry-run",
+            action="store_true",
+            dest="dry_run",
+            default=False,
+            help=(
+                "Don't actually install anything, just print what would be. "
+                "Can be used in combination with --ignore-installed "
+                "to 'resolve' the requirements."
+            ),
+        )
+        self.cmd_opts.add_option(
+            "-t",
+            "--target",
+            dest="target_dir",
+            metavar="dir",
             default=None,
-            help='Install packages into <dir>. '
-                 'By default this will not replace existing files/folders in '
-                 '<dir>. Use --upgrade to replace existing packages in <dir> '
-                 'with new versions.'
+            help=(
+                "Install packages into <dir>. "
+                "By default this will not replace existing files/folders in "
+                "<dir>. Use --upgrade to replace existing packages in <dir> "
+                "with new versions."
+            ),
         )
         cmdoptions.add_target_python_options(self.cmd_opts)
 
         self.cmd_opts.add_option(
-            '--user',
-            dest='use_user_site',
-            action='store_true',
-            help="Install to the Python user install directory for your "
-                 "platform. Typically ~/.local/, or %APPDATA%\\Python on "
-                 "Windows. (See the Python documentation for site.USER_BASE "
-                 "for full details.)")
+            "--user",
+            dest="use_user_site",
+            action="store_true",
+            help=(
+                "Install to the Python user install directory for your "
+                "platform. Typically ~/.local/, or %APPDATA%\\Python on "
+                "Windows. (See the Python documentation for site.USER_BASE "
+                "for full details.)"
+            ),
+        )
         self.cmd_opts.add_option(
-            '--no-user',
-            dest='use_user_site',
-            action='store_false',
-            help=SUPPRESS_HELP)
+            "--no-user",
+            dest="use_user_site",
+            action="store_false",
+            help=SUPPRESS_HELP,
+        )
         self.cmd_opts.add_option(
-            '--root',
-            dest='root_path',
-            metavar='dir',
+            "--root",
+            dest="root_path",
+            metavar="dir",
             default=None,
-            help="Install everything relative to this alternate root "
-                 "directory.")
+            help="Install everything relative to this alternate root directory.",
+        )
         self.cmd_opts.add_option(
-            '--prefix',
-            dest='prefix_path',
-            metavar='dir',
+            "--prefix",
+            dest="prefix_path",
+            metavar="dir",
             default=None,
-            help="Installation prefix where lib, bin and other top-level "
-                 "folders are placed")
-
-        self.cmd_opts.add_option(cmdoptions.build_dir())
+            help=(
+                "Installation prefix where lib, bin and other top-level "
+                "folders are placed. Note that the resulting installation may "
+                "contain scripts and other resources which reference the "
+                "Python interpreter of pip, and not that of ``--prefix``. "
+                "See also the ``--python`` option if the intention is to "
+                "install packages into another (possibly pip-free) "
+                "environment."
+            ),
+        )
 
         self.cmd_opts.add_option(cmdoptions.src())
 
         self.cmd_opts.add_option(
-            '-U', '--upgrade',
-            dest='upgrade',
-            action='store_true',
-            help='Upgrade all specified packages to the newest available '
-                 'version. The handling of dependencies depends on the '
-                 'upgrade-strategy used.'
+            "-U",
+            "--upgrade",
+            dest="upgrade",
+            action="store_true",
+            help=(
+                "Upgrade all specified packages to the newest available "
+                "version. The handling of dependencies depends on the "
+                "upgrade-strategy used."
+            ),
         )
 
         self.cmd_opts.add_option(
-            '--upgrade-strategy',
-            dest='upgrade_strategy',
-            default='only-if-needed',
-            choices=['only-if-needed', 'eager'],
-            help='Determines how dependency upgrading should be handled '
-                 '[default: %default]. '
-                 '"eager" - dependencies are upgraded regardless of '
-                 'whether the currently installed version satisfies the '
-                 'requirements of the upgraded package(s). '
-                 '"only-if-needed" -  are upgraded only when they do not '
-                 'satisfy the requirements of the upgraded package(s).'
+            "--upgrade-strategy",
+            dest="upgrade_strategy",
+            default="only-if-needed",
+            choices=["only-if-needed", "eager"],
+            help=(
+                "Determines how dependency upgrading should be handled "
+                "[default: %default]. "
+                '"eager" - dependencies are upgraded regardless of '
+                "whether the currently installed version satisfies the "
+                "requirements of the upgraded package(s). "
+                '"only-if-needed" -  are upgraded only when they do not '
+                "satisfy the requirements of the upgraded package(s)."
+            ),
         )
 
         self.cmd_opts.add_option(
-            '--force-reinstall',
-            dest='force_reinstall',
-            action='store_true',
-            help='Reinstall all packages even if they are already '
-                 'up-to-date.')
+            "--force-reinstall",
+            dest="force_reinstall",
+            action="store_true",
+            help="Reinstall all packages even if they are already up-to-date.",
+        )
 
         self.cmd_opts.add_option(
-            '-I', '--ignore-installed',
-            dest='ignore_installed',
-            action='store_true',
-            help='Ignore the installed packages, overwriting them. '
-                 'This can break your system if the existing package '
-                 'is of a different version or was installed '
-                 'with a different package manager!'
+            "-I",
+            "--ignore-installed",
+            dest="ignore_installed",
+            action="store_true",
+            help=(
+                "Ignore the installed packages, overwriting them. "
+                "This can break your system if the existing package "
+                "is of a different version or was installed "
+                "with a different package manager!"
+            ),
         )
 
         self.cmd_opts.add_option(cmdoptions.ignore_requires_python())
         self.cmd_opts.add_option(cmdoptions.no_build_isolation())
         self.cmd_opts.add_option(cmdoptions.use_pep517())
         self.cmd_opts.add_option(cmdoptions.no_use_pep517())
+        self.cmd_opts.add_option(cmdoptions.check_build_deps())
+        self.cmd_opts.add_option(cmdoptions.override_externally_managed())
 
-        self.cmd_opts.add_option(cmdoptions.install_options())
+        self.cmd_opts.add_option(cmdoptions.config_settings())
         self.cmd_opts.add_option(cmdoptions.global_options())
 
         self.cmd_opts.add_option(
@@ -206,12 +231,12 @@ class InstallCommand(RequirementCommand):
             default=True,
             help="Do not warn about broken dependencies",
         )
-
         self.cmd_opts.add_option(cmdoptions.no_binary())
         self.cmd_opts.add_option(cmdoptions.only_binary())
         self.cmd_opts.add_option(cmdoptions.prefer_binary())
         self.cmd_opts.add_option(cmdoptions.require_hashes())
         self.cmd_opts.add_option(cmdoptions.progress_bar())
+        self.cmd_opts.add_option(cmdoptions.root_user_action())
 
         index_opts = cmdoptions.make_option_group(
             cmdoptions.index_group,
@@ -221,20 +246,50 @@ class InstallCommand(RequirementCommand):
         self.parser.insert_option_group(0, index_opts)
         self.parser.insert_option_group(0, self.cmd_opts)
 
+        self.cmd_opts.add_option(
+            "--report",
+            dest="json_report_file",
+            metavar="file",
+            default=None,
+            help=(
+                "Generate a JSON file describing what pip did to install "
+                "the provided requirements. "
+                "Can be used in combination with --dry-run and --ignore-installed "
+                "to 'resolve' the requirements. "
+                "When - is used as file name it writes to stdout. "
+                "When writing to stdout, please combine with the --quiet option "
+                "to avoid mixing pip logging output with JSON output."
+            ),
+        )
+
     @with_cleanup
     def run(self, options: Values, args: List[str]) -> int:
         if options.use_user_site and options.target_dir is not None:
             raise CommandError("Can not combine '--user' and '--target'")
 
-        cmdoptions.check_install_build_global(options)
+        # Check whether the environment we're installing into is externally
+        # managed, as specified in PEP 668. Specifying --root, --target, or
+        # --prefix disables the check, since there's no reliable way to locate
+        # the EXTERNALLY-MANAGED file for those cases. An exception is also
+        # made specifically for "--dry-run --report" for convenience.
+        installing_into_current_environment = (
+            not (options.dry_run and options.json_report_file)
+            and options.root_path is None
+            and options.target_dir is None
+            and options.prefix_path is None
+        )
+        if (
+            installing_into_current_environment
+            and not options.override_externally_managed
+        ):
+            check_externally_managed()
+
         upgrade_strategy = "to-satisfy-only"
         if options.upgrade:
             upgrade_strategy = options.upgrade_strategy
 
         cmdoptions.check_dist_restriction(options, check_target=True)
 
-        install_options = options.install_options or []
-
         logger.verbose("Using %s", get_pip_version())
         options.use_user_site = decide_user_install(
             options.use_user_site,
@@ -249,11 +304,14 @@ class InstallCommand(RequirementCommand):
         if options.target_dir:
             options.ignore_installed = True
             options.target_dir = os.path.abspath(options.target_dir)
-            if (os.path.exists(options.target_dir) and not
-                    os.path.isdir(options.target_dir)):
+            if (
+                # fmt: off
+                os.path.exists(options.target_dir) and
+                not os.path.isdir(options.target_dir)
+                # fmt: on
+            ):
                 raise CommandError(
-                    "Target path exists but is not a directory, will not "
-                    "continue."
+                    "Target path exists but is not a directory, will not continue."
                 )
 
             # Create a target directory for using with the target option
@@ -272,9 +330,7 @@ class InstallCommand(RequirementCommand):
             target_python=target_python,
             ignore_requires_python=options.ignore_requires_python,
         )
-        wheel_cache = WheelCache(options.cache_dir, options.format_control)
-
-        req_tracker = self.enter_context(get_requirement_tracker())
+        build_tracker = self.enter_context(get_build_tracker())
 
         directory = TempDirectory(
             delete=not options.no_clean,
@@ -284,18 +340,24 @@ class InstallCommand(RequirementCommand):
 
         try:
             reqs = self.get_requirements(args, options, finder, session)
+            check_legacy_setup_py_options(options, reqs)
 
-            reject_location_related_install_options(
-                reqs, options.install_options
-            )
+            wheel_cache = WheelCache(options.cache_dir)
+
+            # Only when installing is it permitted to use PEP 660.
+            # In other circumstances (pip wheel, pip download) we generate
+            # regular (i.e. non editable) metadata and wheels.
+            for req in reqs:
+                req.permit_editable_wheels = True
 
             preparer = self.make_requirement_preparer(
                 temp_build_dir=directory,
                 options=options,
-                req_tracker=req_tracker,
+                build_tracker=build_tracker,
                 session=session,
                 finder=finder,
                 use_user_site=options.use_user_site,
+                verbosity=self.verbosity,
             )
             resolver = self.make_resolver(
                 preparer=preparer,
@@ -316,6 +378,26 @@ class InstallCommand(RequirementCommand):
                 reqs, check_supported_wheels=not options.target_dir
             )
 
+            if options.json_report_file:
+                report = InstallationReport(requirement_set.requirements_to_install)
+                if options.json_report_file == "-":
+                    print_json(data=report.to_dict())
+                else:
+                    with open(options.json_report_file, "w", encoding="utf-8") as f:
+                        json.dump(report.to_dict(), f, indent=2, ensure_ascii=False)
+
+            if options.dry_run:
+                would_install_items = sorted(
+                    (r.metadata["name"], r.metadata["version"])
+                    for r in requirement_set.requirements_to_install
+                )
+                if would_install_items:
+                    write_output(
+                        "Would install %s",
+                        " ".join("-".join(item) for item in would_install_items),
+                    )
+                return SUCCESS
+
             try:
                 pip_req = requirement_set.get_requirement("pip")
             except KeyError:
@@ -324,19 +406,12 @@ class InstallCommand(RequirementCommand):
                 # If we're not replacing an already installed pip,
                 # we're not modifying it.
                 modifying_pip = pip_req.satisfied_by is None
-            protect_pip_from_modification_on_windows(
-                modifying_pip=modifying_pip
-            )
-
-            check_binary_allowed = get_check_binary_allowed(
-                finder.format_control
-            )
+            protect_pip_from_modification_on_windows(modifying_pip=modifying_pip)
 
             reqs_to_build = [
-                r for r in requirement_set.requirements.values()
-                if should_build_for_install_command(
-                    r, check_binary_allowed
-                )
+                r
+                for r in requirement_set.requirements.values()
+                if should_build_for_install_command(r)
             ]
 
             _, build_failures = build(
@@ -344,39 +419,23 @@ class InstallCommand(RequirementCommand):
                 wheel_cache=wheel_cache,
                 verify=True,
                 build_options=[],
-                global_options=[],
+                global_options=global_options,
             )
 
-            # If we're using PEP 517, we cannot do a direct install
-            # so we fail here.
-            pep517_build_failure_names: List[str] = [
-                r.name   # type: ignore
-                for r in build_failures if r.use_pep517
-            ]
-            if pep517_build_failure_names:
+            if build_failures:
                 raise InstallationError(
-                    "Could not build wheels for {} which use"
-                    " PEP 517 and cannot be installed directly".format(
-                        ", ".join(pep517_build_failure_names)
+                    "Could not build wheels for {}, which is required to "
+                    "install pyproject.toml-based projects".format(
+                        ", ".join(r.name for r in build_failures)  # type: ignore
                     )
                 )
 
-            # For now, we just warn about failures building legacy
-            # requirements, as we'll fall through to a direct
-            # install for those.
-            for r in build_failures:
-                if not r.use_pep517:
-                    r.legacy_install_reason = 8368
-
-            to_install = resolver.get_installation_order(
-                requirement_set
-            )
+            to_install = resolver.get_installation_order(requirement_set)
 
             # Check for conflicts in the package set we're installing.
             conflicts: Optional[ConflictDetails] = None
             should_warn_about_conflicts = (
-                not options.ignore_dependencies and
-                options.warn_about_conflicts
+                not options.ignore_dependencies and options.warn_about_conflicts
             )
             if should_warn_about_conflicts:
                 conflicts = self._determine_conflicts(to_install)
@@ -389,7 +448,6 @@ class InstallCommand(RequirementCommand):
 
             installed = install_given_reqs(
                 to_install,
-                install_options,
                 global_options,
                 root=options.root_path,
                 home=target_temp_dir_path,
@@ -408,7 +466,7 @@ class InstallCommand(RequirementCommand):
             )
             env = get_environment(lib_locations)
 
-            installed.sort(key=operator.attrgetter('name'))
+            installed.sort(key=operator.attrgetter("name"))
             items = []
             for result in installed:
                 item = result.name
@@ -426,16 +484,19 @@ class InstallCommand(RequirementCommand):
                     resolver_variant=self.determine_resolver_variant(options),
                 )
 
-            installed_desc = ' '.join(items)
+            installed_desc = " ".join(items)
             if installed_desc:
                 write_output(
-                    'Successfully installed %s', installed_desc,
+                    "Successfully installed %s",
+                    installed_desc,
                 )
         except OSError as error:
-            show_traceback = (self.verbosity >= 1)
+            show_traceback = self.verbosity >= 1
 
             message = create_os_error_message(
-                error, show_traceback, options.use_user_site,
+                error,
+                show_traceback,
+                options.use_user_site,
             )
             logger.error(message, exc_info=show_traceback)  # noqa
 
@@ -446,8 +507,8 @@ class InstallCommand(RequirementCommand):
             self._handle_target_dir(
                 options.target_dir, target_temp_dir, options.upgrade
             )
-
-        warn_if_run_as_root()
+        if options.root_user_action == "warn":
+            warn_if_run_as_root()
         return SUCCESS
 
     def _handle_target_dir(
@@ -461,7 +522,7 @@ class InstallCommand(RequirementCommand):
 
         # Checking both purelib and platlib directories for installed
         # packages to be moved to target directory
-        scheme = get_scheme('', home=target_temp_dir.path)
+        scheme = get_scheme("", home=target_temp_dir.path)
         purelib_dir = scheme.purelib
         platlib_dir = scheme.platlib
         data_dir = scheme.data
@@ -483,18 +544,18 @@ class InstallCommand(RequirementCommand):
                 if os.path.exists(target_item_dir):
                     if not upgrade:
                         logger.warning(
-                            'Target directory %s already exists. Specify '
-                            '--upgrade to force replacement.',
-                            target_item_dir
+                            "Target directory %s already exists. Specify "
+                            "--upgrade to force replacement.",
+                            target_item_dir,
                         )
                         continue
                     if os.path.islink(target_item_dir):
                         logger.warning(
-                            'Target directory %s already exists and is '
-                            'a link. pip will not automatically replace '
-                            'links, please remove if replacement is '
-                            'desired.',
-                            target_item_dir
+                            "Target directory %s already exists and is "
+                            "a link. pip will not automatically replace "
+                            "links, please remove if replacement is "
+                            "desired.",
+                            target_item_dir,
                         )
                         continue
                     if os.path.isdir(target_item_dir):
@@ -502,10 +563,7 @@ class InstallCommand(RequirementCommand):
                     else:
                         os.remove(target_item_dir)
 
-                shutil.move(
-                    os.path.join(lib_dir, item),
-                    target_item_dir
-                )
+                shutil.move(os.path.join(lib_dir, item), target_item_dir)
 
     def _determine_conflicts(
         self, to_install: List[InstallRequirement]
@@ -567,7 +625,7 @@ class InstallCommand(RequirementCommand):
                     requirement=req,
                     dep_name=dep_name,
                     dep_version=dep_version,
-                    you=("you" if resolver_variant == "2020-resolver" else "you'll")
+                    you=("you" if resolver_variant == "2020-resolver" else "you'll"),
                 )
                 parts.append(message)
 
@@ -575,14 +633,14 @@ class InstallCommand(RequirementCommand):
 
 
 def get_lib_location_guesses(
-        user: bool = False,
-        home: Optional[str] = None,
-        root: Optional[str] = None,
-        isolated: bool = False,
-        prefix: Optional[str] = None
+    user: bool = False,
+    home: Optional[str] = None,
+    root: Optional[str] = None,
+    isolated: bool = False,
+    prefix: Optional[str] = None,
 ) -> List[str]:
     scheme = get_scheme(
-        '',
+        "",
         user=user,
         home=home,
         root=root,
@@ -594,8 +652,8 @@ def get_lib_location_guesses(
 
 def site_packages_writable(root: Optional[str], isolated: bool) -> bool:
     return all(
-        test_writable_dir(d) for d in set(
-            get_lib_location_guesses(root=root, isolated=isolated))
+        test_writable_dir(d)
+        for d in set(get_lib_location_guesses(root=root, isolated=isolated))
     )
 
 
@@ -653,51 +711,11 @@ def decide_user_install(
         logger.debug("Non-user install because site-packages writeable")
         return False
 
-    logger.info("Defaulting to user installation because normal site-packages "
-                "is not writeable")
-    return True
-
-
-def reject_location_related_install_options(
-    requirements: List[InstallRequirement], options: Optional[List[str]]
-) -> None:
-    """If any location-changing --install-option arguments were passed for
-    requirements or on the command-line, then show a deprecation warning.
-    """
-    def format_options(option_names: Iterable[str]) -> List[str]:
-        return ["--{}".format(name.replace("_", "-")) for name in option_names]
-
-    offenders = []
-
-    for requirement in requirements:
-        install_options = requirement.install_options
-        location_options = parse_distutils_args(install_options)
-        if location_options:
-            offenders.append(
-                "{!r} from {}".format(
-                    format_options(location_options.keys()), requirement
-                )
-            )
-
-    if options:
-        location_options = parse_distutils_args(options)
-        if location_options:
-            offenders.append(
-                "{!r} from command line".format(
-                    format_options(location_options.keys())
-                )
-            )
-
-    if not offenders:
-        return
-
-    raise CommandError(
-        "Location-changing options found in --install-option: {}."
-        " This is unsupported, use pip-level options like --user,"
-        " --prefix, --root, and --target instead.".format(
-            "; ".join(offenders)
-        )
+    logger.info(
+        "Defaulting to user installation because normal site-packages "
+        "is not writeable"
     )
+    return True
 
 
 def create_os_error_message(
@@ -727,18 +745,25 @@ def create_os_error_message(
         permissions_part = "Check the permissions"
 
         if not running_under_virtualenv() and not using_user_site:
-            parts.extend([
-                user_option_part, " or ",
-                permissions_part.lower(),
-            ])
+            parts.extend(
+                [
+                    user_option_part,
+                    " or ",
+                    permissions_part.lower(),
+                ]
+            )
         else:
             parts.append(permissions_part)
         parts.append(".\n")
 
     # Suggest the user to enable Long Paths if path length is
     # more than 260
-    if (WINDOWS and error.errno == errno.ENOENT and error.filename and
-            len(error.filename) > 260):
+    if (
+        WINDOWS
+        and error.errno == errno.ENOENT
+        and error.filename
+        and len(error.filename) > 260
+    ):
         parts.append(
             "HINT: This error might have occurred since "
             "this system does not have Windows Long Path "

venv/Lib/site-packages/pip/_internal/commands/list.py

@@ -1,7 +1,7 @@
 import json
 import logging
 from optparse import Values
-from typing import TYPE_CHECKING, Iterator, List, Optional, Sequence, Tuple, cast
+from typing import TYPE_CHECKING, Generator, List, Optional, Sequence, Tuple, cast
 
 from pip._vendor.packaging.utils import canonicalize_name
 
@@ -14,8 +14,8 @@ from pip._internal.index.package_finder import PackageFinder
 from pip._internal.metadata import BaseDistribution, get_environment
 from pip._internal.models.selection_prefs import SelectionPreferences
 from pip._internal.network.session import PipSession
-from pip._internal.utils.misc import stdlib_pkgs, tabulate, write_output
-from pip._internal.utils.parallel import map_multithread
+from pip._internal.utils.compat import stdlib_pkgs
+from pip._internal.utils.misc import tabulate, write_output
 
 if TYPE_CHECKING:
     from pip._internal.metadata.base import DistributionVersion
@@ -26,6 +26,7 @@ if TYPE_CHECKING:
         These will be populated during ``get_outdated()``. This is dirty but
         makes the rest of the code much cleaner.
         """
+
         latest_version: DistributionVersion
         latest_filetype: str
 
@@ -48,77 +49,85 @@ class ListCommand(IndexGroupCommand):
 
     def add_options(self) -> None:
         self.cmd_opts.add_option(
-            '-o', '--outdated',
-            action='store_true',
+            "-o",
+            "--outdated",
+            action="store_true",
             default=False,
-            help='List outdated packages')
-        self.cmd_opts.add_option(
-            '-u', '--uptodate',
-            action='store_true',
-            default=False,
-            help='List uptodate packages')
-        self.cmd_opts.add_option(
-            '-e', '--editable',
-            action='store_true',
-            default=False,
-            help='List editable projects.')
-        self.cmd_opts.add_option(
-            '-l', '--local',
-            action='store_true',
-            default=False,
-            help=('If in a virtualenv that has global access, do not list '
-                  'globally-installed packages.'),
+            help="List outdated packages",
         )
         self.cmd_opts.add_option(
-            '--user',
-            dest='user',
-            action='store_true',
+            "-u",
+            "--uptodate",
+            action="store_true",
             default=False,
-            help='Only output packages installed in user-site.')
+            help="List uptodate packages",
+        )
+        self.cmd_opts.add_option(
+            "-e",
+            "--editable",
+            action="store_true",
+            default=False,
+            help="List editable projects.",
+        )
+        self.cmd_opts.add_option(
+            "-l",
+            "--local",
+            action="store_true",
+            default=False,
+            help=(
+                "If in a virtualenv that has global access, do not list "
+                "globally-installed packages."
+            ),
+        )
+        self.cmd_opts.add_option(
+            "--user",
+            dest="user",
+            action="store_true",
+            default=False,
+            help="Only output packages installed in user-site.",
+        )
         self.cmd_opts.add_option(cmdoptions.list_path())
         self.cmd_opts.add_option(
-            '--pre',
-            action='store_true',
+            "--pre",
+            action="store_true",
             default=False,
-            help=("Include pre-release and development versions. By default, "
-                  "pip only finds stable versions."),
+            help=(
+                "Include pre-release and development versions. By default, "
+                "pip only finds stable versions."
+            ),
         )
 
         self.cmd_opts.add_option(
-            '--format',
-            action='store',
-            dest='list_format',
+            "--format",
+            action="store",
+            dest="list_format",
             default="columns",
-            choices=('columns', 'freeze', 'json'),
-            help="Select the output format among: columns (default), freeze, "
-                 "or json",
+            choices=("columns", "freeze", "json"),
+            help="Select the output format among: columns (default), freeze, or json",
         )
 
         self.cmd_opts.add_option(
-            '--not-required',
-            action='store_true',
-            dest='not_required',
-            help="List packages that are not dependencies of "
-                 "installed packages.",
+            "--not-required",
+            action="store_true",
+            dest="not_required",
+            help="List packages that are not dependencies of installed packages.",
         )
 
         self.cmd_opts.add_option(
-            '--exclude-editable',
-            action='store_false',
-            dest='include_editable',
-            help='Exclude editable package from output.',
+            "--exclude-editable",
+            action="store_false",
+            dest="include_editable",
+            help="Exclude editable package from output.",
         )
         self.cmd_opts.add_option(
-            '--include-editable',
-            action='store_true',
-            dest='include_editable',
-            help='Include editable package from output.',
+            "--include-editable",
+            action="store_true",
+            dest="include_editable",
+            help="Include editable package from output.",
             default=True,
         )
         self.cmd_opts.add_option(cmdoptions.list_exclude())
-        index_opts = cmdoptions.make_option_group(
-            cmdoptions.index_group, self.parser
-        )
+        index_opts = cmdoptions.make_option_group(cmdoptions.index_group, self.parser)
 
         self.parser.insert_option_group(0, index_opts)
         self.parser.insert_option_group(0, self.cmd_opts)
@@ -144,8 +153,12 @@ class ListCommand(IndexGroupCommand):
 
     def run(self, options: Values, args: List[str]) -> int:
         if options.outdated and options.uptodate:
+            raise CommandError("Options --outdated and --uptodate cannot be combined.")
+
+        if options.outdated and options.list_format == "freeze":
             raise CommandError(
-                "Options --outdated and --uptodate cannot be combined.")
+                "List format 'freeze' can not be used with the --outdated option."
+            )
 
         cmdoptions.check_list_path_option(options)
 
@@ -183,7 +196,8 @@ class ListCommand(IndexGroupCommand):
         self, packages: "_ProcessedDists", options: Values
     ) -> "_ProcessedDists":
         return [
-            dist for dist in self.iter_packages_latest_infos(packages, options)
+            dist
+            for dist in self.iter_packages_latest_infos(packages, options)
             if dist.latest_version > dist.version
         ]
 
@@ -191,7 +205,8 @@ class ListCommand(IndexGroupCommand):
         self, packages: "_ProcessedDists", options: Values
     ) -> "_ProcessedDists":
         return [
-            dist for dist in self.iter_packages_latest_infos(packages, options)
+            dist
+            for dist in self.iter_packages_latest_infos(packages, options)
             if dist.latest_version == dist.version
         ]
 
@@ -211,18 +226,21 @@ class ListCommand(IndexGroupCommand):
 
     def iter_packages_latest_infos(
         self, packages: "_ProcessedDists", options: Values
-    ) -> Iterator["_DistWithLatestInfo"]:
+    ) -> Generator["_DistWithLatestInfo", None, None]:
         with self._build_session(options) as session:
             finder = self._build_package_finder(options, session)
 
             def latest_info(
-                dist: "_DistWithLatestInfo"
+                dist: "_DistWithLatestInfo",
             ) -> Optional["_DistWithLatestInfo"]:
                 all_candidates = finder.find_all_candidates(dist.canonical_name)
                 if not options.pre:
                     # Remove prereleases
-                    all_candidates = [candidate for candidate in all_candidates
-                                      if not candidate.version.is_prerelease]
+                    all_candidates = [
+                        candidate
+                        for candidate in all_candidates
+                        if not candidate.version.is_prerelease
+                    ]
 
                 evaluator = finder.make_candidate_evaluator(
                     project_name=dist.canonical_name,
@@ -233,14 +251,14 @@ class ListCommand(IndexGroupCommand):
 
                 remote_version = best_candidate.version
                 if best_candidate.link.is_wheel:
-                    typ = 'wheel'
+                    typ = "wheel"
                 else:
-                    typ = 'sdist'
+                    typ = "sdist"
                 dist.latest_version = remote_version
                 dist.latest_filetype = typ
                 return dist
 
-            for dist in map_multithread(latest_info, packages):
+            for dist in map(latest_info, packages):
                 if dist is not None:
                     yield dist
 
@@ -251,17 +269,18 @@ class ListCommand(IndexGroupCommand):
             packages,
             key=lambda dist: dist.canonical_name,
         )
-        if options.list_format == 'columns' and packages:
+        if options.list_format == "columns" and packages:
             data, header = format_for_columns(packages, options)
             self.output_package_listing_columns(data, header)
-        elif options.list_format == 'freeze':
+        elif options.list_format == "freeze":
             for dist in packages:
                 if options.verbose >= 1:
-                    write_output("%s==%s (%s)", dist.raw_name,
-                                 dist.version, dist.location)
+                    write_output(
+                        "%s==%s (%s)", dist.raw_name, dist.version, dist.location
+                    )
                 else:
                     write_output("%s==%s", dist.raw_name, dist.version)
-        elif options.list_format == 'json':
+        elif options.list_format == "json":
             write_output(format_for_json(packages, options))
 
     def output_package_listing_columns(
@@ -275,7 +294,7 @@ class ListCommand(IndexGroupCommand):
 
         # Create and add a separator.
         if len(data) > 0:
-            pkg_strings.insert(1, " ".join(map(lambda x: '-' * x, sizes)))
+            pkg_strings.insert(1, " ".join(map(lambda x: "-" * x, sizes)))
 
         for val in pkg_strings:
             write_output(val)
@@ -288,19 +307,22 @@ def format_for_columns(
     Convert the package data into something usable
     by output_package_listing_columns.
     """
-    running_outdated = options.outdated
-    # Adjust the header for the `pip list --outdated` case.
-    if running_outdated:
-        header = ["Package", "Version", "Latest", "Type"]
-    else:
-        header = ["Package", "Version"]
+    header = ["Package", "Version"]
 
-    data = []
-    if options.verbose >= 1 or any(x.editable for x in pkgs):
+    running_outdated = options.outdated
+    if running_outdated:
+        header.extend(["Latest", "Type"])
+
+    has_editables = any(x.editable for x in pkgs)
+    if has_editables:
+        header.append("Editable project location")
+
+    if options.verbose >= 1:
         header.append("Location")
     if options.verbose >= 1:
         header.append("Installer")
 
+    data = []
     for proj in pkgs:
         # if we're working on the 'outdated' list, separate out the
         # latest_version and type
@@ -310,7 +332,10 @@ def format_for_columns(
             row.append(str(proj.latest_version))
             row.append(proj.latest_filetype)
 
-        if options.verbose >= 1 or proj.editable:
+        if has_editables:
+            row.append(proj.editable_project_location or "")
+
+        if options.verbose >= 1:
             row.append(proj.location or "")
         if options.verbose >= 1:
             row.append(proj.installer)
@@ -324,14 +349,17 @@ def format_for_json(packages: "_ProcessedDists", options: Values) -> str:
     data = []
     for dist in packages:
         info = {
-            'name': dist.raw_name,
-            'version': str(dist.version),
+            "name": dist.raw_name,
+            "version": str(dist.version),
         }
         if options.verbose >= 1:
-            info['location'] = dist.location or ""
-            info['installer'] = dist.installer
+            info["location"] = dist.location or ""
+            info["installer"] = dist.installer
         if options.outdated:
-            info['latest_version'] = str(dist.latest_version)
-            info['latest_filetype'] = dist.latest_filetype
+            info["latest_version"] = str(dist.latest_version)
+            info["latest_filetype"] = dist.latest_filetype
+        editable_project_location = dist.editable_project_location
+        if editable_project_location:
+            info["editable_project_location"] = editable_project_location
         data.append(info)
     return json.dumps(data)

venv/Lib/site-packages/pip/_internal/commands/search.py

@@ -27,6 +27,7 @@ if TYPE_CHECKING:
         summary: str
         versions: List[str]
 
+
 logger = logging.getLogger(__name__)
 
 
@@ -39,17 +40,19 @@ class SearchCommand(Command, SessionCommandMixin):
 
     def add_options(self) -> None:
         self.cmd_opts.add_option(
-            '-i', '--index',
-            dest='index',
-            metavar='URL',
+            "-i",
+            "--index",
+            dest="index",
+            metavar="URL",
             default=PyPI.pypi_url,
-            help='Base URL of Python Package Index (default %default)')
+            help="Base URL of Python Package Index (default %default)",
+        )
 
         self.parser.insert_option_group(0, self.cmd_opts)
 
     def run(self, options: Values, args: List[str]) -> int:
         if not args:
-            raise CommandError('Missing required argument (search query).')
+            raise CommandError("Missing required argument (search query).")
         query = args
         pypi_hits = self.search(query, options)
         hits = transform_hits(pypi_hits)
@@ -71,7 +74,7 @@ class SearchCommand(Command, SessionCommandMixin):
         transport = PipXmlrpcTransport(index_url, session)
         pypi = xmlrpc.client.ServerProxy(index_url, transport)
         try:
-            hits = pypi.search({'name': query, 'summary': query}, 'or')
+            hits = pypi.search({"name": query, "summary": query}, "or")
         except xmlrpc.client.Fault as fault:
             message = "XMLRPC request failed [code: {code}]\n{string}".format(
                 code=fault.faultCode,
@@ -90,22 +93,22 @@ def transform_hits(hits: List[Dict[str, str]]) -> List["TransformedHit"]:
     """
     packages: Dict[str, "TransformedHit"] = OrderedDict()
     for hit in hits:
-        name = hit['name']
-        summary = hit['summary']
-        version = hit['version']
+        name = hit["name"]
+        summary = hit["summary"]
+        version = hit["version"]
 
         if name not in packages.keys():
             packages[name] = {
-                'name': name,
-                'summary': summary,
-                'versions': [version],
+                "name": name,
+                "summary": summary,
+                "versions": [version],
             }
         else:
-            packages[name]['versions'].append(version)
+            packages[name]["versions"].append(version)
 
             # if this is the highest version, replace summary and score
-            if version == highest_version(packages[name]['versions']):
-                packages[name]['summary'] = summary
+            if version == highest_version(packages[name]["versions"]):
+                packages[name]["summary"] = summary
 
     return list(packages.values())
 
@@ -116,14 +119,17 @@ def print_dist_installation_info(name: str, latest: str) -> None:
     if dist is not None:
         with indent_log():
             if dist.version == latest:
-                write_output('INSTALLED: %s (latest)', dist.version)
+                write_output("INSTALLED: %s (latest)", dist.version)
             else:
-                write_output('INSTALLED: %s', dist.version)
+                write_output("INSTALLED: %s", dist.version)
                 if parse_version(latest).pre:
-                    write_output('LATEST:    %s (pre-release; install'
-                                 ' with "pip install --pre")', latest)
+                    write_output(
+                        "LATEST:    %s (pre-release; install"
+                        " with `pip install --pre`)",
+                        latest,
+                    )
                 else:
-                    write_output('LATEST:    %s', latest)
+                    write_output("LATEST:    %s", latest)
 
 
 def print_results(
@@ -134,25 +140,29 @@ def print_results(
     if not hits:
         return
     if name_column_width is None:
-        name_column_width = max([
-            len(hit['name']) + len(highest_version(hit.get('versions', ['-'])))
-            for hit in hits
-        ]) + 4
+        name_column_width = (
+            max(
+                [
+                    len(hit["name"]) + len(highest_version(hit.get("versions", ["-"])))
+                    for hit in hits
+                ]
+            )
+            + 4
+        )
 
     for hit in hits:
-        name = hit['name']
-        summary = hit['summary'] or ''
-        latest = highest_version(hit.get('versions', ['-']))
+        name = hit["name"]
+        summary = hit["summary"] or ""
+        latest = highest_version(hit.get("versions", ["-"]))
         if terminal_width is not None:
             target_width = terminal_width - name_column_width - 5
             if target_width > 10:
                 # wrap and indent summary to fit terminal
                 summary_lines = textwrap.wrap(summary, target_width)
-                summary = ('\n' + ' ' * (name_column_width + 3)).join(
-                    summary_lines)
+                summary = ("\n" + " " * (name_column_width + 3)).join(summary_lines)
 
-        name_latest = f'{name} ({latest})'
-        line = f'{name_latest:{name_column_width}} - {summary}'
+        name_latest = f"{name} ({latest})"
+        line = f"{name_latest:{name_column_width}} - {summary}"
         try:
             write_output(line)
             print_dist_installation_info(name, latest)

venv/Lib/site-packages/pip/_internal/commands/show.py

@@ -1,8 +1,6 @@
-import csv
 import logging
-import pathlib
 from optparse import Values
-from typing import Iterator, List, NamedTuple, Optional, Tuple
+from typing import Generator, Iterable, Iterator, List, NamedTuple, Optional
 
 from pip._vendor.packaging.utils import canonicalize_name
 
@@ -27,23 +25,26 @@ class ShowCommand(Command):
 
     def add_options(self) -> None:
         self.cmd_opts.add_option(
-            '-f', '--files',
-            dest='files',
-            action='store_true',
+            "-f",
+            "--files",
+            dest="files",
+            action="store_true",
             default=False,
-            help='Show the full list of installed files for each package.')
+            help="Show the full list of installed files for each package.",
+        )
 
         self.parser.insert_option_group(0, self.cmd_opts)
 
     def run(self, options: Values, args: List[str]) -> int:
         if not args:
-            logger.warning('ERROR: Please provide a package name or names.')
+            logger.warning("ERROR: Please provide a package name or names.")
             return ERROR
         query = args
 
         results = search_packages_info(query)
         if not print_results(
-                results, list_files=options.files, verbose=options.verbose):
+            results, list_files=options.files, verbose=options.verbose
+        ):
             return ERROR
         return SUCCESS
 
@@ -52,6 +53,7 @@ class _PackageInfo(NamedTuple):
     name: str
     version: str
     location: str
+    editable_project_location: Optional[str]
     requires: List[str]
     required_by: List[str]
     installer: str
@@ -59,6 +61,7 @@ class _PackageInfo(NamedTuple):
     classifiers: List[str]
     summary: str
     homepage: str
+    project_urls: List[str]
     author: str
     author_email: str
     license: str
@@ -66,34 +69,7 @@ class _PackageInfo(NamedTuple):
     files: Optional[List[str]]
 
 
-def _covert_legacy_entry(entry: Tuple[str, ...], info: Tuple[str, ...]) -> str:
-    """Convert a legacy installed-files.txt path into modern RECORD path.
-
-    The legacy format stores paths relative to the info directory, while the
-    modern format stores paths relative to the package root, e.g. the
-    site-packages directory.
-
-    :param entry: Path parts of the installed-files.txt entry.
-    :param info: Path parts of the egg-info directory relative to package root.
-    :returns: The converted entry.
-
-    For best compatibility with symlinks, this does not use ``abspath()`` or
-    ``Path.resolve()``, but tries to work with path parts:
-
-    1. While ``entry`` starts with ``..``, remove the equal amounts of parts
-       from ``info``; if ``info`` is empty, start appending ``..`` instead.
-    2. Join the two directly.
-    """
-    while entry and entry[0] == "..":
-        if not info or info[-1] == "..":
-            info += ("..",)
-        else:
-            info = info[:-1]
-        entry = entry[1:]
-    return str(pathlib.Path(*info, *entry))
-
-
-def search_packages_info(query: List[str]) -> Iterator[_PackageInfo]:
+def search_packages_info(query: List[str]) -> Generator[_PackageInfo, None, None]:
     """
     Gather details from installed distributions. Print distribution name,
     version, location, and installed files. Installed files requires a
@@ -102,53 +78,20 @@ def search_packages_info(query: List[str]) -> Iterator[_PackageInfo]:
     """
     env = get_default_environment()
 
-    installed = {
-        dist.canonical_name: dist
-        for dist in env.iter_distributions()
-    }
+    installed = {dist.canonical_name: dist for dist in env.iter_all_distributions()}
     query_names = [canonicalize_name(name) for name in query]
     missing = sorted(
         [name for name, pkg in zip(query, query_names) if pkg not in installed]
     )
     if missing:
-        logger.warning('Package(s) not found: %s', ', '.join(missing))
+        logger.warning("Package(s) not found: %s", ", ".join(missing))
 
-    def _get_requiring_packages(current_dist: BaseDistribution) -> List[str]:
-        return [
+    def _get_requiring_packages(current_dist: BaseDistribution) -> Iterator[str]:
+        return (
             dist.metadata["Name"] or "UNKNOWN"
             for dist in installed.values()
-            if current_dist.canonical_name in {
-                canonicalize_name(d.name) for d in dist.iter_dependencies()
-            }
-        ]
-
-    def _files_from_record(dist: BaseDistribution) -> Optional[Iterator[str]]:
-        try:
-            text = dist.read_text('RECORD')
-        except FileNotFoundError:
-            return None
-        # This extra Path-str cast normalizes entries.
-        return (str(pathlib.Path(row[0])) for row in csv.reader(text.splitlines()))
-
-    def _files_from_legacy(dist: BaseDistribution) -> Optional[Iterator[str]]:
-        try:
-            text = dist.read_text('installed-files.txt')
-        except FileNotFoundError:
-            return None
-        paths = (p for p in text.splitlines(keepends=False) if p)
-        root = dist.location
-        info = dist.info_directory
-        if root is None or info is None:
-            return paths
-        try:
-            info_rel = pathlib.Path(info).relative_to(root)
-        except ValueError:  # info is not relative to root.
-            return paths
-        if not info_rel.parts:  # info *is* root.
-            return paths
-        return (
-            _covert_legacy_entry(pathlib.Path(p).parts, info_rel.parts)
-            for p in paths
+            if current_dist.canonical_name
+            in {canonicalize_name(d.name) for d in dist.iter_dependencies()}
         )
 
     for query_name in query_names:
@@ -157,13 +100,16 @@ def search_packages_info(query: List[str]) -> Iterator[_PackageInfo]:
         except KeyError:
             continue
 
+        requires = sorted((req.name for req in dist.iter_dependencies()), key=str.lower)
+        required_by = sorted(_get_requiring_packages(dist), key=str.lower)
+
         try:
-            entry_points_text = dist.read_text('entry_points.txt')
+            entry_points_text = dist.read_text("entry_points.txt")
             entry_points = entry_points_text.splitlines(keepends=False)
         except FileNotFoundError:
             entry_points = []
 
-        files_iter = _files_from_record(dist) or _files_from_legacy(dist)
+        files_iter = dist.iter_declared_entries()
         if files_iter is None:
             files: Optional[List[str]] = None
         else:
@@ -175,13 +121,15 @@ def search_packages_info(query: List[str]) -> Iterator[_PackageInfo]:
             name=dist.raw_name,
             version=str(dist.version),
             location=dist.location or "",
-            requires=[req.name for req in dist.iter_dependencies()],
-            required_by=_get_requiring_packages(dist),
+            editable_project_location=dist.editable_project_location,
+            requires=requires,
+            required_by=required_by,
             installer=dist.installer,
             metadata_version=dist.metadata_version or "",
             classifiers=metadata.get_all("Classifier", []),
             summary=metadata.get("Summary", ""),
             homepage=metadata.get("Home-page", ""),
+            project_urls=metadata.get_all("Project-URL", []),
             author=metadata.get("Author", ""),
             author_email=metadata.get("Author-email", ""),
             license=metadata.get("License", ""),
@@ -191,7 +139,7 @@ def search_packages_info(query: List[str]) -> Iterator[_PackageInfo]:
 
 
 def print_results(
-    distributions: Iterator[_PackageInfo],
+    distributions: Iterable[_PackageInfo],
     list_files: bool,
     verbose: bool,
 ) -> bool:
@@ -212,8 +160,12 @@ def print_results(
         write_output("Author-email: %s", dist.author_email)
         write_output("License: %s", dist.license)
         write_output("Location: %s", dist.location)
-        write_output("Requires: %s", ', '.join(dist.requires))
-        write_output("Required-by: %s", ', '.join(dist.required_by))
+        if dist.editable_project_location is not None:
+            write_output(
+                "Editable project location: %s", dist.editable_project_location
+            )
+        write_output("Requires: %s", ", ".join(dist.requires))
+        write_output("Required-by: %s", ", ".join(dist.required_by))
 
         if verbose:
             write_output("Metadata-Version: %s", dist.metadata_version)
@@ -224,6 +176,9 @@ def print_results(
             write_output("Entry-points:")
             for entry in dist.entry_points:
                 write_output("  %s", entry.strip())
+            write_output("Project-URLs:")
+            for project_url in dist.project_urls:
+                write_output("  %s", project_url)
         if list_files:
             write_output("Files:")
             if dist.files is None:

venv/Lib/site-packages/pip/_internal/commands/uninstall.py

@@ -4,6 +4,7 @@ from typing import List
 
 from pip._vendor.packaging.utils import canonicalize_name
 
+from pip._internal.cli import cmdoptions
 from pip._internal.cli.base_command import Command
 from pip._internal.cli.req_command import SessionCommandMixin, warn_if_run_as_root
 from pip._internal.cli.status_codes import SUCCESS
@@ -13,7 +14,10 @@ from pip._internal.req.constructors import (
     install_req_from_line,
     install_req_from_parsed_requirement,
 )
-from pip._internal.utils.misc import protect_pip_from_modification_on_windows
+from pip._internal.utils.misc import (
+    check_externally_managed,
+    protect_pip_from_modification_on_windows,
+)
 
 logger = logging.getLogger(__name__)
 
@@ -35,20 +39,26 @@ class UninstallCommand(Command, SessionCommandMixin):
 
     def add_options(self) -> None:
         self.cmd_opts.add_option(
-            '-r', '--requirement',
-            dest='requirements',
-            action='append',
+            "-r",
+            "--requirement",
+            dest="requirements",
+            action="append",
             default=[],
-            metavar='file',
-            help='Uninstall all the packages listed in the given requirements '
-                 'file.  This option can be used multiple times.',
+            metavar="file",
+            help=(
+                "Uninstall all the packages listed in the given requirements "
+                "file.  This option can be used multiple times."
+            ),
         )
         self.cmd_opts.add_option(
-            '-y', '--yes',
-            dest='yes',
-            action='store_true',
-            help="Don't ask for confirmation of uninstall deletions.")
-
+            "-y",
+            "--yes",
+            dest="yes",
+            action="store_true",
+            help="Don't ask for confirmation of uninstall deletions.",
+        )
+        self.cmd_opts.add_option(cmdoptions.root_user_action())
+        self.cmd_opts.add_option(cmdoptions.override_externally_managed())
         self.parser.insert_option_group(0, self.cmd_opts)
 
     def run(self, options: Values, args: List[str]) -> int:
@@ -57,7 +67,8 @@ class UninstallCommand(Command, SessionCommandMixin):
         reqs_to_uninstall = {}
         for name in args:
             req = install_req_from_line(
-                name, isolated=options.isolated_mode,
+                name,
+                isolated=options.isolated_mode,
             )
             if req.name:
                 reqs_to_uninstall[canonicalize_name(req.name)] = req
@@ -70,31 +81,33 @@ class UninstallCommand(Command, SessionCommandMixin):
                 )
         for filename in options.requirements:
             for parsed_req in parse_requirements(
-                    filename,
-                    options=options,
-                    session=session):
+                filename, options=options, session=session
+            ):
                 req = install_req_from_parsed_requirement(
-                    parsed_req,
-                    isolated=options.isolated_mode
+                    parsed_req, isolated=options.isolated_mode
                 )
                 if req.name:
                     reqs_to_uninstall[canonicalize_name(req.name)] = req
         if not reqs_to_uninstall:
             raise InstallationError(
-                f'You must give at least one requirement to {self.name} (see '
+                f"You must give at least one requirement to {self.name} (see "
                 f'"pip help {self.name}")'
             )
 
+        if not options.override_externally_managed:
+            check_externally_managed()
+
         protect_pip_from_modification_on_windows(
             modifying_pip="pip" in reqs_to_uninstall
         )
 
         for req in reqs_to_uninstall.values():
             uninstall_pathset = req.uninstall(
-                auto_confirm=options.yes, verbose=self.verbosity > 0,
+                auto_confirm=options.yes,
+                verbose=self.verbosity > 0,
             )
             if uninstall_pathset:
                 uninstall_pathset.commit()
-
-        warn_if_run_as_root()
+        if options.root_user_action == "warn":
+            warn_if_run_as_root()
         return SUCCESS

venv/Lib/site-packages/pip/_internal/commands/wheel.py

@@ -9,8 +9,11 @@ from pip._internal.cli import cmdoptions
 from pip._internal.cli.req_command import RequirementCommand, with_cleanup
 from pip._internal.cli.status_codes import SUCCESS
 from pip._internal.exceptions import CommandError
-from pip._internal.req.req_install import InstallRequirement
-from pip._internal.req.req_tracker import get_requirement_tracker
+from pip._internal.operations.build.build_tracker import get_build_tracker
+from pip._internal.req.req_install import (
+    InstallRequirement,
+    check_legacy_setup_py_options,
+)
 from pip._internal.utils.misc import ensure_dir, normalize_path
 from pip._internal.utils.temp_dir import TempDirectory
 from pip._internal.wheel_builder import build, should_build_for_wheel_command
@@ -26,10 +29,8 @@ class WheelCommand(RequirementCommand):
     recompiling your software during every install. For more details, see the
     wheel docs: https://wheel.readthedocs.io/en/latest/
 
-    Requirements: setuptools>=0.8, and wheel.
-
-    'pip wheel' uses the bdist_wheel setuptools extension from the wheel
-    package to build individual wheels.
+    'pip wheel' uses the build system interface as described here:
+    https://pip.pypa.io/en/stable/reference/build-system/
 
     """
 
@@ -41,14 +42,16 @@ class WheelCommand(RequirementCommand):
       %prog [options] <archive url/path> ..."""
 
     def add_options(self) -> None:
-
         self.cmd_opts.add_option(
-            '-w', '--wheel-dir',
-            dest='wheel_dir',
-            metavar='dir',
+            "-w",
+            "--wheel-dir",
+            dest="wheel_dir",
+            metavar="dir",
             default=os.curdir,
-            help=("Build wheels into <dir>, where the default is the "
-                  "current working directory."),
+            help=(
+                "Build wheels into <dir>, where the default is the "
+                "current working directory."
+            ),
         )
         self.cmd_opts.add_option(cmdoptions.no_binary())
         self.cmd_opts.add_option(cmdoptions.only_binary())
@@ -56,32 +59,35 @@ class WheelCommand(RequirementCommand):
         self.cmd_opts.add_option(cmdoptions.no_build_isolation())
         self.cmd_opts.add_option(cmdoptions.use_pep517())
         self.cmd_opts.add_option(cmdoptions.no_use_pep517())
+        self.cmd_opts.add_option(cmdoptions.check_build_deps())
         self.cmd_opts.add_option(cmdoptions.constraints())
         self.cmd_opts.add_option(cmdoptions.editable())
         self.cmd_opts.add_option(cmdoptions.requirements())
         self.cmd_opts.add_option(cmdoptions.src())
         self.cmd_opts.add_option(cmdoptions.ignore_requires_python())
         self.cmd_opts.add_option(cmdoptions.no_deps())
-        self.cmd_opts.add_option(cmdoptions.build_dir())
         self.cmd_opts.add_option(cmdoptions.progress_bar())
 
         self.cmd_opts.add_option(
-            '--no-verify',
-            dest='no_verify',
-            action='store_true',
+            "--no-verify",
+            dest="no_verify",
+            action="store_true",
             default=False,
             help="Don't verify if built wheel is valid.",
         )
 
+        self.cmd_opts.add_option(cmdoptions.config_settings())
         self.cmd_opts.add_option(cmdoptions.build_options())
         self.cmd_opts.add_option(cmdoptions.global_options())
 
         self.cmd_opts.add_option(
-            '--pre',
-            action='store_true',
+            "--pre",
+            action="store_true",
             default=False,
-            help=("Include pre-release and development versions. By default, "
-                  "pip only finds stable versions."),
+            help=(
+                "Include pre-release and development versions. By default, "
+                "pip only finds stable versions."
+            ),
         )
 
         self.cmd_opts.add_option(cmdoptions.require_hashes())
@@ -96,17 +102,14 @@ class WheelCommand(RequirementCommand):
 
     @with_cleanup
     def run(self, options: Values, args: List[str]) -> int:
-        cmdoptions.check_install_build_global(options)
-
         session = self.get_default_session(options)
 
         finder = self._build_package_finder(options, session)
-        wheel_cache = WheelCache(options.cache_dir, options.format_control)
 
         options.wheel_dir = normalize_path(options.wheel_dir)
         ensure_dir(options.wheel_dir)
 
-        req_tracker = self.enter_context(get_requirement_tracker())
+        build_tracker = self.enter_context(get_build_tracker())
 
         directory = TempDirectory(
             delete=not options.no_clean,
@@ -115,15 +118,19 @@ class WheelCommand(RequirementCommand):
         )
 
         reqs = self.get_requirements(args, options, finder, session)
+        check_legacy_setup_py_options(options, reqs)
+
+        wheel_cache = WheelCache(options.cache_dir)
 
         preparer = self.make_requirement_preparer(
             temp_build_dir=directory,
             options=options,
-            req_tracker=req_tracker,
+            build_tracker=build_tracker,
             session=session,
             finder=finder,
             download_dir=options.wheel_dir,
             use_user_site=False,
+            verbosity=self.verbosity,
         )
 
         resolver = self.make_resolver(
@@ -137,9 +144,7 @@ class WheelCommand(RequirementCommand):
 
         self.trace_basic_info(finder)
 
-        requirement_set = resolver.resolve(
-            reqs, check_supported_wheels=True
-        )
+        requirement_set = resolver.resolve(reqs, check_supported_wheels=True)
 
         reqs_to_build: List[InstallRequirement] = []
         for req in requirement_set.requirements.values():
@@ -165,12 +170,11 @@ class WheelCommand(RequirementCommand):
             except OSError as e:
                 logger.warning(
                     "Building wheel for %s failed: %s",
-                    req.name, e,
+                    req.name,
+                    e,
                 )
                 build_failures.append(req)
         if len(build_failures) != 0:
-            raise CommandError(
-                "Failed to build one or more wheels"
-            )
+            raise CommandError("Failed to build one or more wheels")
 
         return SUCCESS

venv/Lib/site-packages/pip/_internal/configuration.py

@@ -13,7 +13,6 @@ Some terminology:
 
 import configparser
 import locale
-import logging
 import os
 import sys
 from typing import Any, Dict, Iterable, List, NewType, Optional, Tuple
@@ -24,41 +23,39 @@ from pip._internal.exceptions import (
 )
 from pip._internal.utils import appdirs
 from pip._internal.utils.compat import WINDOWS
+from pip._internal.utils.logging import getLogger
 from pip._internal.utils.misc import ensure_dir, enum
 
 RawConfigParser = configparser.RawConfigParser  # Shorthand
 Kind = NewType("Kind", str)
 
-CONFIG_BASENAME = 'pip.ini' if WINDOWS else 'pip.conf'
+CONFIG_BASENAME = "pip.ini" if WINDOWS else "pip.conf"
 ENV_NAMES_IGNORED = "version", "help"
 
 # The kinds of configurations there are.
 kinds = enum(
-    USER="user",        # User Specific
-    GLOBAL="global",    # System Wide
-    SITE="site",        # [Virtual] Environment Specific
-    ENV="env",          # from PIP_CONFIG_FILE
+    USER="user",  # User Specific
+    GLOBAL="global",  # System Wide
+    SITE="site",  # [Virtual] Environment Specific
+    ENV="env",  # from PIP_CONFIG_FILE
     ENV_VAR="env-var",  # from Environment Variables
 )
 OVERRIDE_ORDER = kinds.GLOBAL, kinds.USER, kinds.SITE, kinds.ENV, kinds.ENV_VAR
 VALID_LOAD_ONLY = kinds.USER, kinds.GLOBAL, kinds.SITE
 
-logger = logging.getLogger(__name__)
+logger = getLogger(__name__)
 
 
 # NOTE: Maybe use the optionx attribute to normalize keynames.
-def _normalize_name(name):
-    # type: (str) -> str
-    """Make a name consistent regardless of source (environment or file)
-    """
-    name = name.lower().replace('_', '-')
-    if name.startswith('--'):
+def _normalize_name(name: str) -> str:
+    """Make a name consistent regardless of source (environment or file)"""
+    name = name.lower().replace("_", "-")
+    if name.startswith("--"):
         name = name[2:]  # only prefer long opts
     return name
 
 
-def _disassemble_key(name):
-    # type: (str) -> List[str]
+def _disassemble_key(name: str) -> List[str]:
     if "." not in name:
         error_message = (
             "Key does not contain dot separated section and key. "
@@ -68,22 +65,18 @@ def _disassemble_key(name):
     return name.split(".", 1)
 
 
-def get_configuration_files():
-    # type: () -> Dict[Kind, List[str]]
+def get_configuration_files() -> Dict[Kind, List[str]]:
     global_config_files = [
-        os.path.join(path, CONFIG_BASENAME)
-        for path in appdirs.site_config_dirs('pip')
+        os.path.join(path, CONFIG_BASENAME) for path in appdirs.site_config_dirs("pip")
     ]
 
     site_config_file = os.path.join(sys.prefix, CONFIG_BASENAME)
     legacy_config_file = os.path.join(
-        os.path.expanduser('~'),
-        'pip' if WINDOWS else '.pip',
+        os.path.expanduser("~"),
+        "pip" if WINDOWS else ".pip",
         CONFIG_BASENAME,
     )
-    new_config_file = os.path.join(
-        appdirs.user_config_dir("pip"), CONFIG_BASENAME
-    )
+    new_config_file = os.path.join(appdirs.user_config_dir("pip"), CONFIG_BASENAME)
     return {
         kinds.GLOBAL: global_config_files,
         kinds.SITE: [site_config_file],
@@ -105,8 +98,7 @@ class Configuration:
     and the data stored is also nice.
     """
 
-    def __init__(self, isolated, load_only=None):
-        # type: (bool, Optional[Kind]) -> None
+    def __init__(self, isolated: bool, load_only: Optional[Kind] = None) -> None:
         super().__init__()
 
         if load_only is not None and load_only not in VALID_LOAD_ONLY:
@@ -119,54 +111,50 @@ class Configuration:
         self.load_only = load_only
 
         # Because we keep track of where we got the data from
-        self._parsers = {
+        self._parsers: Dict[Kind, List[Tuple[str, RawConfigParser]]] = {
             variant: [] for variant in OVERRIDE_ORDER
-        }  # type: Dict[Kind, List[Tuple[str, RawConfigParser]]]
-        self._config = {
+        }
+        self._config: Dict[Kind, Dict[str, Any]] = {
             variant: {} for variant in OVERRIDE_ORDER
-        }  # type: Dict[Kind, Dict[str, Any]]
-        self._modified_parsers = []  # type: List[Tuple[str, RawConfigParser]]
+        }
+        self._modified_parsers: List[Tuple[str, RawConfigParser]] = []
 
-    def load(self):
-        # type: () -> None
-        """Loads configuration from configuration files and environment
-        """
+    def load(self) -> None:
+        """Loads configuration from configuration files and environment"""
         self._load_config_files()
         if not self.isolated:
             self._load_environment_vars()
 
-    def get_file_to_edit(self):
-        # type: () -> Optional[str]
-        """Returns the file with highest priority in configuration
-        """
-        assert self.load_only is not None, \
-            "Need to be specified a file to be editing"
+    def get_file_to_edit(self) -> Optional[str]:
+        """Returns the file with highest priority in configuration"""
+        assert self.load_only is not None, "Need to be specified a file to be editing"
 
         try:
             return self._get_parser_to_modify()[0]
         except IndexError:
             return None
 
-    def items(self):
-        # type: () -> Iterable[Tuple[str, Any]]
+    def items(self) -> Iterable[Tuple[str, Any]]:
         """Returns key-value pairs like dict.items() representing the loaded
         configuration
         """
         return self._dictionary.items()
 
-    def get_value(self, key):
-        # type: (str) -> Any
-        """Get a value from the configuration.
-        """
+    def get_value(self, key: str) -> Any:
+        """Get a value from the configuration."""
+        orig_key = key
+        key = _normalize_name(key)
         try:
             return self._dictionary[key]
         except KeyError:
-            raise ConfigurationError(f"No such key - {key}")
+            # disassembling triggers a more useful error message than simply
+            # "No such key" in the case that the key isn't in the form command.option
+            _disassemble_key(key)
+            raise ConfigurationError(f"No such key - {orig_key}")
 
-    def set_value(self, key, value):
-        # type: (str, Any) -> None
-        """Modify a value in the configuration.
-        """
+    def set_value(self, key: str, value: Any) -> None:
+        """Modify a value in the configuration."""
+        key = _normalize_name(key)
         self._ensure_have_load_only()
 
         assert self.load_only
@@ -183,21 +171,23 @@ class Configuration:
         self._config[self.load_only][key] = value
         self._mark_as_modified(fname, parser)
 
-    def unset_value(self, key):
-        # type: (str) -> None
+    def unset_value(self, key: str) -> None:
         """Unset a value in the configuration."""
+        orig_key = key
+        key = _normalize_name(key)
         self._ensure_have_load_only()
 
         assert self.load_only
         if key not in self._config[self.load_only]:
-            raise ConfigurationError(f"No such key - {key}")
+            raise ConfigurationError(f"No such key - {orig_key}")
 
         fname, parser = self._get_parser_to_modify()
 
         if parser is not None:
             section, name = _disassemble_key(key)
-            if not (parser.has_section(section)
-                    and parser.remove_option(section, name)):
+            if not (
+                parser.has_section(section) and parser.remove_option(section, name)
+            ):
                 # The option was not removed.
                 raise ConfigurationError(
                     "Fatal Internal error [id=1]. Please report as a bug."
@@ -210,10 +200,8 @@ class Configuration:
 
         del self._config[self.load_only][key]
 
-    def save(self):
-        # type: () -> None
-        """Save the current in-memory state.
-        """
+    def save(self) -> None:
+        """Save the current in-memory state."""
         self._ensure_have_load_only()
 
         for fname, parser in self._modified_parsers:
@@ -229,17 +217,14 @@ class Configuration:
     # Private routines
     #
 
-    def _ensure_have_load_only(self):
-        # type: () -> None
+    def _ensure_have_load_only(self) -> None:
         if self.load_only is None:
             raise ConfigurationError("Needed a specific file to be modifying.")
         logger.debug("Will be working with %s variant only", self.load_only)
 
     @property
-    def _dictionary(self):
-        # type: () -> Dict[str, Any]
-        """A dictionary representing the loaded configuration.
-        """
+    def _dictionary(self) -> Dict[str, Any]:
+        """A dictionary representing the loaded configuration."""
         # NOTE: Dictionaries are not populated if not loaded. So, conditionals
         #       are not needed here.
         retval = {}
@@ -249,10 +234,8 @@ class Configuration:
 
         return retval
 
-    def _load_config_files(self):
-        # type: () -> None
-        """Loads configuration from configuration files
-        """
+    def _load_config_files(self) -> None:
+        """Loads configuration from configuration files"""
         config_files = dict(self.iter_config_files())
         if config_files[kinds.ENV][0:1] == [os.devnull]:
             logger.debug(
@@ -266,9 +249,7 @@ class Configuration:
                 # If there's specific variant set in `load_only`, load only
                 # that variant, not the others.
                 if self.load_only is not None and variant != self.load_only:
-                    logger.debug(
-                        "Skipping file '%s' (variant: %s)", fname, variant
-                    )
+                    logger.debug("Skipping file '%s' (variant: %s)", fname, variant)
                     continue
 
                 parser = self._load_file(variant, fname)
@@ -276,9 +257,8 @@ class Configuration:
                 # Keeping track of the parsers used
                 self._parsers[variant].append((fname, parser))
 
-    def _load_file(self, variant, fname):
-        # type: (Kind, str) -> RawConfigParser
-        logger.debug("For variant '%s', will try loading '%s'", variant, fname)
+    def _load_file(self, variant: Kind, fname: str) -> RawConfigParser:
+        logger.verbose("For variant '%s', will try loading '%s'", variant, fname)
         parser = self._construct_parser(fname)
 
         for section in parser.sections():
@@ -287,22 +267,20 @@ class Configuration:
 
         return parser
 
-    def _construct_parser(self, fname):
-        # type: (str) -> RawConfigParser
+    def _construct_parser(self, fname: str) -> RawConfigParser:
         parser = configparser.RawConfigParser()
         # If there is no such file, don't bother reading it but create the
         # parser anyway, to hold the data.
         # Doing this is useful when modifying and saving files, where we don't
         # need to construct a parser.
         if os.path.exists(fname):
+            locale_encoding = locale.getpreferredencoding(False)
             try:
-                parser.read(fname)
+                parser.read(fname, encoding=locale_encoding)
             except UnicodeDecodeError:
                 # See https://github.com/pypa/pip/issues/4963
                 raise ConfigurationFileCouldNotBeLoaded(
-                    reason="contains invalid {} characters".format(
-                        locale.getpreferredencoding(False)
-                    ),
+                    reason=f"contains invalid {locale_encoding} characters",
                     fname=fname,
                 )
             except configparser.Error as error:
@@ -310,16 +288,15 @@ class Configuration:
                 raise ConfigurationFileCouldNotBeLoaded(error=error)
         return parser
 
-    def _load_environment_vars(self):
-        # type: () -> None
-        """Loads configuration from environment variables
-        """
+    def _load_environment_vars(self) -> None:
+        """Loads configuration from environment variables"""
         self._config[kinds.ENV_VAR].update(
             self._normalized_keys(":env:", self.get_environ_vars())
         )
 
-    def _normalized_keys(self, section, items):
-        # type: (str, Iterable[Tuple[str, Any]]) -> Dict[str, Any]
+    def _normalized_keys(
+        self, section: str, items: Iterable[Tuple[str, Any]]
+    ) -> Dict[str, Any]:
         """Normalizes items to construct a dictionary with normalized keys.
 
         This routine is where the names become keys and are made the same
@@ -331,8 +308,7 @@ class Configuration:
             normalized[key] = val
         return normalized
 
-    def get_environ_vars(self):
-        # type: () -> Iterable[Tuple[str, str]]
+    def get_environ_vars(self) -> Iterable[Tuple[str, str]]:
         """Returns a generator with all environmental vars with prefix PIP_"""
         for key, val in os.environ.items():
             if key.startswith("PIP_"):
@@ -341,8 +317,7 @@ class Configuration:
                     yield name, val
 
     # XXX: This is patched in the tests.
-    def iter_config_files(self):
-        # type: () -> Iterable[Tuple[Kind, List[str]]]
+    def iter_config_files(self) -> Iterable[Tuple[Kind, List[str]]]:
         """Yields variant and configuration files associated with it.
 
         This should be treated like items of a dictionary.
@@ -350,7 +325,7 @@ class Configuration:
         # SMELL: Move the conditions out of this function
 
         # environment variables have the lowest priority
-        config_file = os.environ.get('PIP_CONFIG_FILE', None)
+        config_file = os.environ.get("PIP_CONFIG_FILE", None)
         if config_file is not None:
             yield kinds.ENV, [config_file]
         else:
@@ -372,13 +347,11 @@ class Configuration:
         # finally virtualenv configuration first trumping others
         yield kinds.SITE, config_files[kinds.SITE]
 
-    def get_values_in_config(self, variant):
-        # type: (Kind) -> Dict[str, Any]
+    def get_values_in_config(self, variant: Kind) -> Dict[str, Any]:
         """Get values present in a config file"""
         return self._config[variant]
 
-    def _get_parser_to_modify(self):
-        # type: () -> Tuple[str, RawConfigParser]
+    def _get_parser_to_modify(self) -> Tuple[str, RawConfigParser]:
         # Determine which parser to modify
         assert self.load_only
         parsers = self._parsers[self.load_only]
@@ -392,12 +365,10 @@ class Configuration:
         return parsers[-1]
 
     # XXX: This is patched in the tests.
-    def _mark_as_modified(self, fname, parser):
-        # type: (str, RawConfigParser) -> None
+    def _mark_as_modified(self, fname: str, parser: RawConfigParser) -> None:
         file_parser_tuple = (fname, parser)
         if file_parser_tuple not in self._modified_parsers:
             self._modified_parsers.append(file_parser_tuple)
 
-    def __repr__(self):
-        # type: () -> str
+    def __repr__(self) -> str:
         return f"{self.__class__.__name__}({self._dictionary!r})"

venv/Lib/site-packages/pip/_internal/distributions/base.py

@@ -1,9 +1,7 @@
 import abc
-from typing import Optional
-
-from pip._vendor.pkg_resources import Distribution
 
 from pip._internal.index.package_finder import PackageFinder
+from pip._internal.metadata.base import BaseDistribution
 from pip._internal.req import InstallRequirement
 
 
@@ -28,11 +26,14 @@ class AbstractDistribution(metaclass=abc.ABCMeta):
         self.req = req
 
     @abc.abstractmethod
-    def get_pkg_resources_distribution(self) -> Optional[Distribution]:
+    def get_metadata_distribution(self) -> BaseDistribution:
         raise NotImplementedError()
 
     @abc.abstractmethod
     def prepare_distribution_metadata(
-        self, finder: PackageFinder, build_isolation: bool
+        self,
+        finder: PackageFinder,
+        build_isolation: bool,
+        check_build_deps: bool,
     ) -> None:
         raise NotImplementedError()

venv/Lib/site-packages/pip/_internal/distributions/installed.py

@@ -1,9 +1,6 @@
-from typing import Optional
-
-from pip._vendor.pkg_resources import Distribution
-
 from pip._internal.distributions.base import AbstractDistribution
 from pip._internal.index.package_finder import PackageFinder
+from pip._internal.metadata import BaseDistribution
 
 
 class InstalledDistribution(AbstractDistribution):
@@ -13,10 +10,14 @@ class InstalledDistribution(AbstractDistribution):
     been computed.
     """
 
-    def get_pkg_resources_distribution(self) -> Optional[Distribution]:
+    def get_metadata_distribution(self) -> BaseDistribution:
+        assert self.req.satisfied_by is not None, "not actually installed"
         return self.req.satisfied_by
 
     def prepare_distribution_metadata(
-        self, finder: PackageFinder, build_isolation: bool
+        self,
+        finder: PackageFinder,
+        build_isolation: bool,
+        check_build_deps: bool,
     ) -> None:
         pass

venv/Lib/site-packages/pip/_internal/distributions/sdist.py

@@ -1,12 +1,11 @@
 import logging
-from typing import Set, Tuple
-
-from pip._vendor.pkg_resources import Distribution
+from typing import Iterable, Set, Tuple
 
 from pip._internal.build_env import BuildEnvironment
 from pip._internal.distributions.base import AbstractDistribution
 from pip._internal.exceptions import InstallationError
 from pip._internal.index.package_finder import PackageFinder
+from pip._internal.metadata import BaseDistribution
 from pip._internal.utils.subprocess import runner_with_spinner_message
 
 logger = logging.getLogger(__name__)
@@ -19,11 +18,14 @@ class SourceDistribution(AbstractDistribution):
     generated, either using PEP 517 or using the legacy `setup.py egg_info`.
     """
 
-    def get_pkg_resources_distribution(self) -> Distribution:
+    def get_metadata_distribution(self) -> BaseDistribution:
         return self.req.get_dist()
 
     def prepare_distribution_metadata(
-        self, finder: PackageFinder, build_isolation: bool
+        self,
+        finder: PackageFinder,
+        build_isolation: bool,
+        check_build_deps: bool,
     ) -> None:
         # Load pyproject.toml, to determine whether PEP 517 is to be used
         self.req.load_pyproject_toml()
@@ -31,28 +33,34 @@ class SourceDistribution(AbstractDistribution):
         # Set up the build isolation, if this requirement should be isolated
         should_isolate = self.req.use_pep517 and build_isolation
         if should_isolate:
-            self._setup_isolation(finder)
-
+            # Setup an isolated environment and install the build backend static
+            # requirements in it.
+            self._prepare_build_backend(finder)
+            # Check that if the requirement is editable, it either supports PEP 660 or
+            # has a setup.py or a setup.cfg. This cannot be done earlier because we need
+            # to setup the build backend to verify it supports build_editable, nor can
+            # it be done later, because we want to avoid installing build requirements
+            # needlessly. Doing it here also works around setuptools generating
+            # UNKNOWN.egg-info when running get_requires_for_build_wheel on a directory
+            # without setup.py nor setup.cfg.
+            self.req.isolated_editable_sanity_check()
+            # Install the dynamic build requirements.
+            self._install_build_reqs(finder)
+        # Check if the current environment provides build dependencies
+        should_check_deps = self.req.use_pep517 and check_build_deps
+        if should_check_deps:
+            pyproject_requires = self.req.pyproject_requires
+            assert pyproject_requires is not None
+            conflicting, missing = self.req.build_env.check_requirements(
+                pyproject_requires
+            )
+            if conflicting:
+                self._raise_conflicts("the backend dependencies", conflicting)
+            if missing:
+                self._raise_missing_reqs(missing)
         self.req.prepare_metadata()
 
-    def _setup_isolation(self, finder: PackageFinder) -> None:
-        def _raise_conflicts(
-            conflicting_with: str, conflicting_reqs: Set[Tuple[str, str]]
-        ) -> None:
-            format_string = (
-                "Some build dependencies for {requirement} "
-                "conflict with {conflicting_with}: {description}."
-            )
-            error_message = format_string.format(
-                requirement=self.req,
-                conflicting_with=conflicting_with,
-                description=", ".join(
-                    f"{installed} is incompatible with {wanted}"
-                    for installed, wanted in sorted(conflicting)
-                ),
-            )
-            raise InstallationError(error_message)
-
+    def _prepare_build_backend(self, finder: PackageFinder) -> None:
         # Isolate in a BuildEnvironment and install the build-time
         # requirements.
         pyproject_requires = self.req.pyproject_requires
@@ -60,13 +68,13 @@ class SourceDistribution(AbstractDistribution):
 
         self.req.build_env = BuildEnvironment()
         self.req.build_env.install_requirements(
-            finder, pyproject_requires, "overlay", "Installing build dependencies"
+            finder, pyproject_requires, "overlay", kind="build dependencies"
         )
         conflicting, missing = self.req.build_env.check_requirements(
             self.req.requirements_to_check
         )
         if conflicting:
-            _raise_conflicts("PEP 517/518 supported requirements", conflicting)
+            self._raise_conflicts("PEP 517/518 supported requirements", conflicting)
         if missing:
             logger.warning(
                 "Missing build requirements in pyproject.toml for %s.",
@@ -77,19 +85,66 @@ class SourceDistribution(AbstractDistribution):
                 "pip cannot fall back to setuptools without %s.",
                 " and ".join(map(repr, sorted(missing))),
             )
-        # Install any extra build dependencies that the backend requests.
-        # This must be done in a second pass, as the pyproject.toml
-        # dependencies must be installed before we can call the backend.
+
+    def _get_build_requires_wheel(self) -> Iterable[str]:
         with self.req.build_env:
             runner = runner_with_spinner_message("Getting requirements to build wheel")
             backend = self.req.pep517_backend
             assert backend is not None
             with backend.subprocess_runner(runner):
-                reqs = backend.get_requires_for_build_wheel()
+                return backend.get_requires_for_build_wheel()
 
-        conflicting, missing = self.req.build_env.check_requirements(reqs)
+    def _get_build_requires_editable(self) -> Iterable[str]:
+        with self.req.build_env:
+            runner = runner_with_spinner_message(
+                "Getting requirements to build editable"
+            )
+            backend = self.req.pep517_backend
+            assert backend is not None
+            with backend.subprocess_runner(runner):
+                return backend.get_requires_for_build_editable()
+
+    def _install_build_reqs(self, finder: PackageFinder) -> None:
+        # Install any extra build dependencies that the backend requests.
+        # This must be done in a second pass, as the pyproject.toml
+        # dependencies must be installed before we can call the backend.
+        if (
+            self.req.editable
+            and self.req.permit_editable_wheels
+            and self.req.supports_pyproject_editable()
+        ):
+            build_reqs = self._get_build_requires_editable()
+        else:
+            build_reqs = self._get_build_requires_wheel()
+        conflicting, missing = self.req.build_env.check_requirements(build_reqs)
         if conflicting:
-            _raise_conflicts("the backend dependencies", conflicting)
+            self._raise_conflicts("the backend dependencies", conflicting)
         self.req.build_env.install_requirements(
-            finder, missing, "normal", "Installing backend dependencies"
+            finder, missing, "normal", kind="backend dependencies"
         )
+
+    def _raise_conflicts(
+        self, conflicting_with: str, conflicting_reqs: Set[Tuple[str, str]]
+    ) -> None:
+        format_string = (
+            "Some build dependencies for {requirement} "
+            "conflict with {conflicting_with}: {description}."
+        )
+        error_message = format_string.format(
+            requirement=self.req,
+            conflicting_with=conflicting_with,
+            description=", ".join(
+                f"{installed} is incompatible with {wanted}"
+                for installed, wanted in sorted(conflicting_reqs)
+            ),
+        )
+        raise InstallationError(error_message)
+
+    def _raise_missing_reqs(self, missing: Set[str]) -> None:
+        format_string = (
+            "Some build dependencies for {requirement} are missing: {missing}."
+        )
+        error_message = format_string.format(
+            requirement=self.req, missing=", ".join(map(repr, sorted(missing)))
+        )
+        raise InstallationError(error_message)

venv/Lib/site-packages/pip/_internal/distributions/wheel.py

@@ -1,10 +1,12 @@
-from zipfile import ZipFile
-
-from pip._vendor.pkg_resources import Distribution
+from pip._vendor.packaging.utils import canonicalize_name
 
 from pip._internal.distributions.base import AbstractDistribution
 from pip._internal.index.package_finder import PackageFinder
-from pip._internal.utils.wheel import pkg_resources_distribution_for_wheel
+from pip._internal.metadata import (
+    BaseDistribution,
+    FilesystemWheel,
+    get_wheel_distribution,
+)
 
 
 class WheelDistribution(AbstractDistribution):
@@ -13,22 +15,20 @@ class WheelDistribution(AbstractDistribution):
     This does not need any preparation as wheels can be directly unpacked.
     """
 
-    def get_pkg_resources_distribution(self) -> Distribution:
+    def get_metadata_distribution(self) -> BaseDistribution:
         """Loads the metadata from the wheel file into memory and returns a
         Distribution that uses it, not relying on the wheel file or
         requirement.
         """
-        # Set as part of preparation during download.
-        assert self.req.local_file_path
-        # Wheels are never unnamed.
-        assert self.req.name
-
-        with ZipFile(self.req.local_file_path, allowZip64=True) as z:
-            return pkg_resources_distribution_for_wheel(
-                z, self.req.name, self.req.local_file_path
-            )
+        assert self.req.local_file_path, "Set as part of preparation during download"
+        assert self.req.name, "Wheels are never unnamed"
+        wheel = FilesystemWheel(self.req.local_file_path)
+        return get_wheel_distribution(wheel, canonicalize_name(self.req.name))
 
     def prepare_distribution_metadata(
-        self, finder: PackageFinder, build_isolation: bool
+        self,
+        finder: PackageFinder,
+        build_isolation: bool,
+        check_build_deps: bool,
     ) -> None:
         pass

venv/Lib/site-packages/pip/_internal/exceptions.py

@@ -1,22 +1,181 @@
-"""Exceptions used throughout package"""
+"""Exceptions used throughout package.
+
+This module MUST NOT try to import from anything within `pip._internal` to
+operate. This is expected to be importable from any/all files within the
+subpackage and, thus, should not depend on them.
+"""
 
 import configparser
+import contextlib
+import locale
+import logging
+import pathlib
+import re
+import sys
 from itertools import chain, groupby, repeat
-from typing import TYPE_CHECKING, Dict, List, Optional
+from typing import TYPE_CHECKING, Dict, Iterator, List, Optional, Union
 
-from pip._vendor.pkg_resources import Distribution
 from pip._vendor.requests.models import Request, Response
+from pip._vendor.rich.console import Console, ConsoleOptions, RenderResult
+from pip._vendor.rich.markup import escape
+from pip._vendor.rich.text import Text
 
 if TYPE_CHECKING:
     from hashlib import _Hash
+    from typing import Literal
 
+    from pip._internal.metadata import BaseDistribution
     from pip._internal.req.req_install import InstallRequirement
 
+logger = logging.getLogger(__name__)
+
+
+#
+# Scaffolding
+#
+def _is_kebab_case(s: str) -> bool:
+    return re.match(r"^[a-z]+(-[a-z]+)*$", s) is not None
+
+
+def _prefix_with_indent(
+    s: Union[Text, str],
+    console: Console,
+    *,
+    prefix: str,
+    indent: str,
+) -> Text:
+    if isinstance(s, Text):
+        text = s
+    else:
+        text = console.render_str(s)
+
+    return console.render_str(prefix, overflow="ignore") + console.render_str(
+        f"\n{indent}", overflow="ignore"
+    ).join(text.split(allow_blank=True))
+
 
 class PipError(Exception):
-    """Base pip exception"""
+    """The base pip error."""
 
 
+class DiagnosticPipError(PipError):
+    """An error, that presents diagnostic information to the user.
+
+    This contains a bunch of logic, to enable pretty presentation of our error
+    messages. Each error gets a unique reference. Each error can also include
+    additional context, a hint and/or a note -- which are presented with the
+    main error message in a consistent style.
+
+    This is adapted from the error output styling in `sphinx-theme-builder`.
+    """
+
+    reference: str
+
+    def __init__(
+        self,
+        *,
+        kind: 'Literal["error", "warning"]' = "error",
+        reference: Optional[str] = None,
+        message: Union[str, Text],
+        context: Optional[Union[str, Text]],
+        hint_stmt: Optional[Union[str, Text]],
+        note_stmt: Optional[Union[str, Text]] = None,
+        link: Optional[str] = None,
+    ) -> None:
+        # Ensure a proper reference is provided.
+        if reference is None:
+            assert hasattr(self, "reference"), "error reference not provided!"
+            reference = self.reference
+        assert _is_kebab_case(reference), "error reference must be kebab-case!"
+
+        self.kind = kind
+        self.reference = reference
+
+        self.message = message
+        self.context = context
+
+        self.note_stmt = note_stmt
+        self.hint_stmt = hint_stmt
+
+        self.link = link
+
+        super().__init__(f"<{self.__class__.__name__}: {self.reference}>")
+
+    def __repr__(self) -> str:
+        return (
+            f"<{self.__class__.__name__}("
+            f"reference={self.reference!r}, "
+            f"message={self.message!r}, "
+            f"context={self.context!r}, "
+            f"note_stmt={self.note_stmt!r}, "
+            f"hint_stmt={self.hint_stmt!r}"
+            ")>"
+        )
+
+    def __rich_console__(
+        self,
+        console: Console,
+        options: ConsoleOptions,
+    ) -> RenderResult:
+        colour = "red" if self.kind == "error" else "yellow"
+
+        yield f"[{colour} bold]{self.kind}[/]: [bold]{self.reference}[/]"
+        yield ""
+
+        if not options.ascii_only:
+            # Present the main message, with relevant context indented.
+            if self.context is not None:
+                yield _prefix_with_indent(
+                    self.message,
+                    console,
+                    prefix=f"[{colour}]×[/] ",
+                    indent=f"[{colour}]│[/] ",
+                )
+                yield _prefix_with_indent(
+                    self.context,
+                    console,
+                    prefix=f"[{colour}]╰─>[/] ",
+                    indent=f"[{colour}]   [/] ",
+                )
+            else:
+                yield _prefix_with_indent(
+                    self.message,
+                    console,
+                    prefix="[red]×[/] ",
+                    indent="  ",
+                )
+        else:
+            yield self.message
+            if self.context is not None:
+                yield ""
+                yield self.context
+
+        if self.note_stmt is not None or self.hint_stmt is not None:
+            yield ""
+
+        if self.note_stmt is not None:
+            yield _prefix_with_indent(
+                self.note_stmt,
+                console,
+                prefix="[magenta bold]note[/]: ",
+                indent="      ",
+            )
+        if self.hint_stmt is not None:
+            yield _prefix_with_indent(
+                self.hint_stmt,
+                console,
+                prefix="[cyan bold]hint[/]: ",
+                indent="      ",
+            )
+
+        if self.link is not None:
+            yield ""
+            yield f"Link: {self.link}"
+
+
+#
+# Actual Errors
+#
 class ConfigurationError(PipError):
     """General exception in configuration"""
 
@@ -29,17 +188,54 @@ class UninstallationError(PipError):
     """General exception during uninstallation"""
 
 
+class MissingPyProjectBuildRequires(DiagnosticPipError):
+    """Raised when pyproject.toml has `build-system`, but no `build-system.requires`."""
+
+    reference = "missing-pyproject-build-system-requires"
+
+    def __init__(self, *, package: str) -> None:
+        super().__init__(
+            message=f"Can not process {escape(package)}",
+            context=Text(
+                "This package has an invalid pyproject.toml file.\n"
+                "The [build-system] table is missing the mandatory `requires` key."
+            ),
+            note_stmt="This is an issue with the package mentioned above, not pip.",
+            hint_stmt=Text("See PEP 518 for the detailed specification."),
+        )
+
+
+class InvalidPyProjectBuildRequires(DiagnosticPipError):
+    """Raised when pyproject.toml an invalid `build-system.requires`."""
+
+    reference = "invalid-pyproject-build-system-requires"
+
+    def __init__(self, *, package: str, reason: str) -> None:
+        super().__init__(
+            message=f"Can not process {escape(package)}",
+            context=Text(
+                "This package has an invalid `build-system.requires` key in "
+                f"pyproject.toml.\n{reason}"
+            ),
+            note_stmt="This is an issue with the package mentioned above, not pip.",
+            hint_stmt=Text("See PEP 518 for the detailed specification."),
+        )
+
+
 class NoneMetadataError(PipError):
-    """
-    Raised when accessing "METADATA" or "PKG-INFO" metadata for a
-    pip._vendor.pkg_resources.Distribution object and
-    `dist.has_metadata('METADATA')` returns True but
-    `dist.get_metadata('METADATA')` returns None (and similarly for
-    "PKG-INFO").
+    """Raised when accessing a Distribution's "METADATA" or "PKG-INFO".
+
+    This signifies an inconsistency, when the Distribution claims to have
+    the metadata file (if not, raise ``FileNotFoundError`` instead), but is
+    not actually able to produce its content. This may be due to permission
+    errors.
     """
 
-    def __init__(self, dist, metadata_name):
-        # type: (Distribution, str) -> None
+    def __init__(
+        self,
+        dist: "BaseDistribution",
+        metadata_name: str,
+    ) -> None:
         """
         :param dist: A Distribution object.
         :param metadata_name: The name of the metadata being accessed
@@ -48,28 +244,24 @@ class NoneMetadataError(PipError):
         self.dist = dist
         self.metadata_name = metadata_name
 
-    def __str__(self):
-        # type: () -> str
+    def __str__(self) -> str:
         # Use `dist` in the error message because its stringification
         # includes more information, like the version and location.
-        return (
-            'None {} metadata found for distribution: {}'.format(
-                self.metadata_name, self.dist,
-            )
+        return "None {} metadata found for distribution: {}".format(
+            self.metadata_name,
+            self.dist,
         )
 
 
 class UserInstallationInvalid(InstallationError):
     """A --user install is requested on an environment without user site."""
 
-    def __str__(self):
-        # type: () -> str
+    def __str__(self) -> str:
         return "User base directory is not specified"
 
 
 class InvalidSchemeCombination(InstallationError):
-    def __str__(self):
-        # type: () -> str
+    def __str__(self) -> str:
         before = ", ".join(str(a) for a in self.args[:-1])
         return f"Cannot set {before} and {self.args[-1]} together"
 
@@ -102,8 +294,12 @@ class PreviousBuildDirError(PipError):
 class NetworkConnectionError(PipError):
     """HTTP connection error"""
 
-    def __init__(self, error_msg, response=None, request=None):
-        # type: (str, Response, Request) -> None
+    def __init__(
+        self,
+        error_msg: str,
+        response: Optional[Response] = None,
+        request: Optional[Request] = None,
+    ) -> None:
         """
         Initialize NetworkConnectionError with  `request` and `response`
         objects.
@@ -111,13 +307,15 @@ class NetworkConnectionError(PipError):
         self.response = response
         self.request = request
         self.error_msg = error_msg
-        if (self.response is not None and not self.request and
-                hasattr(response, 'request')):
+        if (
+            self.response is not None
+            and not self.request
+            and hasattr(response, "request")
+        ):
             self.request = self.response.request
         super().__init__(error_msg, response, request)
 
-    def __str__(self):
-        # type: () -> str
+    def __str__(self) -> str:
         return str(self.error_msg)
 
 
@@ -129,74 +327,122 @@ class UnsupportedWheel(InstallationError):
     """Unsupported wheel."""
 
 
+class InvalidWheel(InstallationError):
+    """Invalid (e.g. corrupt) wheel."""
+
+    def __init__(self, location: str, name: str):
+        self.location = location
+        self.name = name
+
+    def __str__(self) -> str:
+        return f"Wheel '{self.name}' located at {self.location} is invalid."
+
+
 class MetadataInconsistent(InstallationError):
     """Built metadata contains inconsistent information.
 
     This is raised when the metadata contains values (e.g. name and version)
-    that do not match the information previously obtained from sdist filename
-    or user-supplied ``#egg=`` value.
+    that do not match the information previously obtained from sdist filename,
+    user-supplied ``#egg=`` value, or an install requirement name.
     """
-    def __init__(self, ireq, field, f_val, m_val):
-        # type: (InstallRequirement, str, str, str) -> None
+
+    def __init__(
+        self, ireq: "InstallRequirement", field: str, f_val: str, m_val: str
+    ) -> None:
         self.ireq = ireq
         self.field = field
         self.f_val = f_val
         self.m_val = m_val
 
-    def __str__(self):
-        # type: () -> str
-        template = (
-            "Requested {} has inconsistent {}: "
-            "filename has {!r}, but metadata has {!r}"
-        )
-        return template.format(self.ireq, self.field, self.f_val, self.m_val)
-
-
-class InstallationSubprocessError(InstallationError):
-    """A subprocess call failed during installation."""
-    def __init__(self, returncode, description):
-        # type: (int, str) -> None
-        self.returncode = returncode
-        self.description = description
-
-    def __str__(self):
-        # type: () -> str
+    def __str__(self) -> str:
         return (
-            "Command errored out with exit status {}: {} "
-            "Check the logs for full command output."
-        ).format(self.returncode, self.description)
+            f"Requested {self.ireq} has inconsistent {self.field}: "
+            f"expected {self.f_val!r}, but metadata has {self.m_val!r}"
+        )
+
+
+class InstallationSubprocessError(DiagnosticPipError, InstallationError):
+    """A subprocess call failed."""
+
+    reference = "subprocess-exited-with-error"
+
+    def __init__(
+        self,
+        *,
+        command_description: str,
+        exit_code: int,
+        output_lines: Optional[List[str]],
+    ) -> None:
+        if output_lines is None:
+            output_prompt = Text("See above for output.")
+        else:
+            output_prompt = (
+                Text.from_markup(f"[red][{len(output_lines)} lines of output][/]\n")
+                + Text("".join(output_lines))
+                + Text.from_markup(R"[red]\[end of output][/]")
+            )
+
+        super().__init__(
+            message=(
+                f"[green]{escape(command_description)}[/] did not run successfully.\n"
+                f"exit code: {exit_code}"
+            ),
+            context=output_prompt,
+            hint_stmt=None,
+            note_stmt=(
+                "This error originates from a subprocess, and is likely not a "
+                "problem with pip."
+            ),
+        )
+
+        self.command_description = command_description
+        self.exit_code = exit_code
+
+    def __str__(self) -> str:
+        return f"{self.command_description} exited with {self.exit_code}"
+
+
+class MetadataGenerationFailed(InstallationSubprocessError, InstallationError):
+    reference = "metadata-generation-failed"
+
+    def __init__(
+        self,
+        *,
+        package_details: str,
+    ) -> None:
+        super(InstallationSubprocessError, self).__init__(
+            message="Encountered error while generating package metadata.",
+            context=escape(package_details),
+            hint_stmt="See above for details.",
+            note_stmt="This is an issue with the package mentioned above, not pip.",
+        )
+
+    def __str__(self) -> str:
+        return "metadata generation failed"
 
 
 class HashErrors(InstallationError):
     """Multiple HashError instances rolled into one for reporting"""
 
-    def __init__(self):
-        # type: () -> None
-        self.errors = []  # type: List[HashError]
+    def __init__(self) -> None:
+        self.errors: List["HashError"] = []
 
-    def append(self, error):
-        # type: (HashError) -> None
+    def append(self, error: "HashError") -> None:
         self.errors.append(error)
 
-    def __str__(self):
-        # type: () -> str
+    def __str__(self) -> str:
         lines = []
         self.errors.sort(key=lambda e: e.order)
         for cls, errors_of_cls in groupby(self.errors, lambda e: e.__class__):
             lines.append(cls.head)
             lines.extend(e.body() for e in errors_of_cls)
         if lines:
-            return '\n'.join(lines)
-        return ''
+            return "\n".join(lines)
+        return ""
 
-    def __nonzero__(self):
-        # type: () -> bool
+    def __bool__(self) -> bool:
         return bool(self.errors)
 
-    def __bool__(self):
-        # type: () -> bool
-        return self.__nonzero__()
-
 
 class HashError(InstallationError):
     """
@@ -214,12 +460,12 @@ class HashError(InstallationError):
         typically available earlier.
 
     """
-    req = None  # type: Optional[InstallRequirement]
-    head = ''
-    order = -1  # type: int
 
-    def body(self):
-        # type: () -> str
+    req: Optional["InstallRequirement"] = None
+    head = ""
+    order: int = -1
+
+    def body(self) -> str:
         """Return a summary of me for display under the heading.
 
         This default implementation simply prints a description of the
@@ -229,21 +475,19 @@ class HashError(InstallationError):
             its link already populated by the resolver's _populate_link().
 
         """
-        return f'    {self._requirement_name()}'
+        return f"    {self._requirement_name()}"
 
-    def __str__(self):
-        # type: () -> str
-        return f'{self.head}\n{self.body()}'
+    def __str__(self) -> str:
+        return f"{self.head}\n{self.body()}"
 
-    def _requirement_name(self):
-        # type: () -> str
+    def _requirement_name(self) -> str:
         """Return a description of the requirement that triggered me.
 
         This default implementation returns long description of the req, with
         line numbers
 
         """
-        return str(self.req) if self.req else 'unknown package'
+        return str(self.req) if self.req else "unknown package"
 
 
 class VcsHashUnsupported(HashError):
@@ -251,8 +495,10 @@ class VcsHashUnsupported(HashError):
     we don't have a method for hashing those."""
 
     order = 0
-    head = ("Can't verify hashes for these requirements because we don't "
-            "have a way to hash version control repositories:")
+    head = (
+        "Can't verify hashes for these requirements because we don't "
+        "have a way to hash version control repositories:"
+    )
 
 
 class DirectoryUrlHashUnsupported(HashError):
@@ -260,32 +506,34 @@ class DirectoryUrlHashUnsupported(HashError):
     we don't have a method for hashing those."""
 
     order = 1
-    head = ("Can't verify hashes for these file:// requirements because they "
-            "point to directories:")
+    head = (
+        "Can't verify hashes for these file:// requirements because they "
+        "point to directories:"
+    )
 
 
 class HashMissing(HashError):
     """A hash was needed for a requirement but is absent."""
 
     order = 2
-    head = ('Hashes are required in --require-hashes mode, but they are '
-            'missing from some requirements. Here is a list of those '
-            'requirements along with the hashes their downloaded archives '
-            'actually had. Add lines like these to your requirements files to '
-            'prevent tampering. (If you did not enable --require-hashes '
-            'manually, note that it turns on automatically when any package '
-            'has a hash.)')
+    head = (
+        "Hashes are required in --require-hashes mode, but they are "
+        "missing from some requirements. Here is a list of those "
+        "requirements along with the hashes their downloaded archives "
+        "actually had. Add lines like these to your requirements files to "
+        "prevent tampering. (If you did not enable --require-hashes "
+        "manually, note that it turns on automatically when any package "
+        "has a hash.)"
+    )
 
-    def __init__(self, gotten_hash):
-        # type: (str) -> None
+    def __init__(self, gotten_hash: str) -> None:
         """
         :param gotten_hash: The hash of the (possibly malicious) archive we
             just downloaded
         """
         self.gotten_hash = gotten_hash
 
-    def body(self):
-        # type: () -> str
+    def body(self) -> str:
         # Dodge circular import.
         from pip._internal.utils.hashes import FAVORITE_HASH
 
@@ -294,13 +542,16 @@ class HashMissing(HashError):
             # In the case of URL-based requirements, display the original URL
             # seen in the requirements file rather than the package name,
             # so the output can be directly copied into the requirements file.
-            package = (self.req.original_link if self.req.original_link
-                       # In case someone feeds something downright stupid
-                       # to InstallRequirement's constructor.
-                       else getattr(self.req, 'req', None))
-        return '    {} --hash={}:{}'.format(package or 'unknown package',
-                                            FAVORITE_HASH,
-                                            self.gotten_hash)
+            package = (
+                self.req.original_link
+                if self.req.original_link
+                # In case someone feeds something downright stupid
+                # to InstallRequirement's constructor.
+                else getattr(self.req, "req", None)
+            )
+        return "    {} --hash={}:{}".format(
+            package or "unknown package", FAVORITE_HASH, self.gotten_hash
+        )
 
 
 class HashUnpinned(HashError):
@@ -308,8 +559,10 @@ class HashUnpinned(HashError):
     version."""
 
     order = 3
-    head = ('In --require-hashes mode, all requirements must have their '
-            'versions pinned with ==. These do not:')
+    head = (
+        "In --require-hashes mode, all requirements must have their "
+        "versions pinned with ==. These do not:"
+    )
 
 
 class HashMismatch(HashError):
@@ -321,14 +574,16 @@ class HashMismatch(HashError):
         improve its error message.
 
     """
-    order = 4
-    head = ('THESE PACKAGES DO NOT MATCH THE HASHES FROM THE REQUIREMENTS '
-            'FILE. If you have updated the package versions, please update '
-            'the hashes. Otherwise, examine the package contents carefully; '
-            'someone may have tampered with them.')
 
-    def __init__(self, allowed, gots):
-        # type: (Dict[str, List[str]], Dict[str, _Hash]) -> None
+    order = 4
+    head = (
+        "THESE PACKAGES DO NOT MATCH THE HASHES FROM THE REQUIREMENTS "
+        "FILE. If you have updated the package versions, please update "
+        "the hashes. Otherwise, examine the package contents carefully; "
+        "someone may have tampered with them."
+    )
+
+    def __init__(self, allowed: Dict[str, List[str]], gots: Dict[str, "_Hash"]) -> None:
         """
         :param allowed: A dict of algorithm names pointing to lists of allowed
             hex digests
@@ -338,13 +593,10 @@ class HashMismatch(HashError):
         self.allowed = allowed
         self.gots = gots
 
-    def body(self):
-        # type: () -> str
-        return '    {}:\n{}'.format(self._requirement_name(),
-                                    self._hash_comparison())
+    def body(self) -> str:
+        return "    {}:\n{}".format(self._requirement_name(), self._hash_comparison())
 
-    def _hash_comparison(self):
-        # type: () -> str
+    def _hash_comparison(self) -> str:
         """
         Return a comparison of actual and expected hash values.
 
@@ -355,20 +607,22 @@ class HashMismatch(HashError):
                     Got        bcdefbcdefbcdefbcdefbcdefbcdefbcdefbcdefbcdef
 
         """
-        def hash_then_or(hash_name):
-            # type: (str) -> chain[str]
+
+        def hash_then_or(hash_name: str) -> "chain[str]":
             # For now, all the decent hashes have 6-char names, so we can get
             # away with hard-coding space literals.
-            return chain([hash_name], repeat('    or'))
+            return chain([hash_name], repeat("    or"))
 
-        lines = []  # type: List[str]
+        lines: List[str] = []
         for hash_name, expecteds in self.allowed.items():
             prefix = hash_then_or(hash_name)
-            lines.extend(('        Expected {} {}'.format(next(prefix), e))
-                         for e in expecteds)
-            lines.append('             Got        {}\n'.format(
-                         self.gots[hash_name].hexdigest()))
-        return '\n'.join(lines)
+            lines.extend(
+                ("        Expected {} {}".format(next(prefix), e)) for e in expecteds
+            )
+            lines.append(
+                "             Got        {}\n".format(self.gots[hash_name].hexdigest())
+            )
+        return "\n".join(lines)
 
 
 class UnsupportedPythonVersion(InstallationError):
@@ -377,21 +631,103 @@ class UnsupportedPythonVersion(InstallationError):
 
 
 class ConfigurationFileCouldNotBeLoaded(ConfigurationError):
-    """When there are errors while loading a configuration file
-    """
+    """When there are errors while loading a configuration file"""
 
-    def __init__(self, reason="could not be loaded", fname=None, error=None):
-        # type: (str, Optional[str], Optional[configparser.Error]) -> None
+    def __init__(
+        self,
+        reason: str = "could not be loaded",
+        fname: Optional[str] = None,
+        error: Optional[configparser.Error] = None,
+    ) -> None:
         super().__init__(error)
         self.reason = reason
         self.fname = fname
         self.error = error
 
-    def __str__(self):
-        # type: () -> str
+    def __str__(self) -> str:
         if self.fname is not None:
             message_part = f" in {self.fname}."
         else:
             assert self.error is not None
             message_part = f".\n{self.error}\n"
         return f"Configuration file {self.reason}{message_part}"
+
+
+_DEFAULT_EXTERNALLY_MANAGED_ERROR = f"""\
+The Python environment under {sys.prefix} is managed externally, and may not be
+manipulated by the user. Please use specific tooling from the distributor of
+the Python installation to interact with this environment instead.
+"""
+
+
+class ExternallyManagedEnvironment(DiagnosticPipError):
+    """The current environment is externally managed.
+
+    This is raised when the current environment is externally managed, as
+    defined by `PEP 668`_. The ``EXTERNALLY-MANAGED`` configuration is checked
+    and displayed when the error is bubbled up to the user.
+
+    :param error: The error message read from ``EXTERNALLY-MANAGED``.
+    """
+
+    reference = "externally-managed-environment"
+
+    def __init__(self, error: Optional[str]) -> None:
+        if error is None:
+            context = Text(_DEFAULT_EXTERNALLY_MANAGED_ERROR)
+        else:
+            context = Text(error)
+        super().__init__(
+            message="This environment is externally managed",
+            context=context,
+            note_stmt=(
+                "If you believe this is a mistake, please contact your "
+                "Python installation or OS distribution provider. "
+                "You can override this, at the risk of breaking your Python "
+                "installation or OS, by passing --break-system-packages."
+            ),
+            hint_stmt=Text("See PEP 668 for the detailed specification."),
+        )
+
+    @staticmethod
+    def _iter_externally_managed_error_keys() -> Iterator[str]:
+        # LC_MESSAGES is in POSIX, but not the C standard. The most common
+        # platform that does not implement this category is Windows, where
+        # using other categories for console message localization is equally
+        # unreliable, so we fall back to the locale-less vendor message. This
+        # can always be re-evaluated when a vendor proposes a new alternative.
+        try:
+            category = locale.LC_MESSAGES
+        except AttributeError:
+            lang: Optional[str] = None
+        else:
+            lang, _ = locale.getlocale(category)
+        if lang is not None:
+            yield f"Error-{lang}"
+            for sep in ("-", "_"):
+                before, found, _ = lang.partition(sep)
+                if not found:
+                    continue
+                yield f"Error-{before}"
+        yield "Error"
+
+    @classmethod
+    def from_config(
+        cls,
+        config: Union[pathlib.Path, str],
+    ) -> "ExternallyManagedEnvironment":
+        parser = configparser.ConfigParser(interpolation=None)
+        try:
+            parser.read(config, encoding="utf-8")
+            section = parser["externally-managed"]
+            for key in cls._iter_externally_managed_error_keys():
+                with contextlib.suppress(KeyError):
+                    return cls(section[key])
+        except KeyError:
+            pass
+        except (OSError, UnicodeDecodeError, configparser.ParsingError):
+            from pip._internal.utils._log import VERBOSE
+
+            exc_info = logger.isEnabledFor(VERBOSE)
+            logger.warning("Failed to read %s", config, exc_info=exc_info)
+        return cls(None)

venv/Lib/site-packages/pip/_internal/index/collector.py

@@ -2,30 +2,32 @@
 The main purpose of this module is to expose LinkCollector.collect_sources().
 """
 
-import cgi
 import collections
+import email.message
 import functools
-import html
 import itertools
+import json
 import logging
 import os
-import re
 import urllib.parse
 import urllib.request
-import xml.etree.ElementTree
+from html.parser import HTMLParser
 from optparse import Values
 from typing import (
+    TYPE_CHECKING,
     Callable,
+    Dict,
     Iterable,
     List,
     MutableMapping,
     NamedTuple,
     Optional,
     Sequence,
+    Tuple,
     Union,
 )
 
-from pip._vendor import html5lib, requests
+from pip._vendor import requests
 from pip._vendor.requests import Response
 from pip._vendor.requests.exceptions import RetryError, SSLError
 
@@ -35,14 +37,18 @@ from pip._internal.models.search_scope import SearchScope
 from pip._internal.network.session import PipSession
 from pip._internal.network.utils import raise_for_status
 from pip._internal.utils.filetypes import is_archive_file
-from pip._internal.utils.misc import pairwise, redact_auth_from_url
+from pip._internal.utils.misc import redact_auth_from_url
 from pip._internal.vcs import vcs
 
 from .sources import CandidatesFromPage, LinkSource, build_source
 
+if TYPE_CHECKING:
+    from typing import Protocol
+else:
+    Protocol = object
+
 logger = logging.getLogger(__name__)
 
-HTMLElement = xml.etree.ElementTree.Element
 ResponseHeaders = MutableMapping[str, str]
 
 
@@ -52,70 +58,90 @@ def _match_vcs_scheme(url: str) -> Optional[str]:
     Returns the matched VCS scheme, or None if there's no match.
     """
     for scheme in vcs.schemes:
-        if url.lower().startswith(scheme) and url[len(scheme)] in '+:':
+        if url.lower().startswith(scheme) and url[len(scheme)] in "+:":
             return scheme
     return None
 
 
-class _NotHTML(Exception):
+class _NotAPIContent(Exception):
     def __init__(self, content_type: str, request_desc: str) -> None:
         super().__init__(content_type, request_desc)
         self.content_type = content_type
         self.request_desc = request_desc
 
 
-def _ensure_html_header(response: Response) -> None:
-    """Check the Content-Type header to ensure the response contains HTML.
-
-    Raises `_NotHTML` if the content type is not text/html.
+def _ensure_api_header(response: Response) -> None:
     """
-    content_type = response.headers.get("Content-Type", "")
-    if not content_type.lower().startswith("text/html"):
-        raise _NotHTML(content_type, response.request.method)
+    Check the Content-Type header to ensure the response contains a Simple
+    API Response.
+
+    Raises `_NotAPIContent` if the content type is not a valid content-type.
+    """
+    content_type = response.headers.get("Content-Type", "Unknown")
+
+    content_type_l = content_type.lower()
+    if content_type_l.startswith(
+        (
+            "text/html",
+            "application/vnd.pypi.simple.v1+html",
+            "application/vnd.pypi.simple.v1+json",
+        )
+    ):
+        return
+
+    raise _NotAPIContent(content_type, response.request.method)
 
 
 class _NotHTTP(Exception):
     pass
 
 
-def _ensure_html_response(url: str, session: PipSession) -> None:
-    """Send a HEAD request to the URL, and ensure the response contains HTML.
+def _ensure_api_response(url: str, session: PipSession) -> None:
+    """
+    Send a HEAD request to the URL, and ensure the response contains a simple
+    API Response.
 
     Raises `_NotHTTP` if the URL is not available for a HEAD request, or
-    `_NotHTML` if the content type is not text/html.
+    `_NotAPIContent` if the content type is not a valid content type.
     """
     scheme, netloc, path, query, fragment = urllib.parse.urlsplit(url)
-    if scheme not in {'http', 'https'}:
+    if scheme not in {"http", "https"}:
         raise _NotHTTP()
 
     resp = session.head(url, allow_redirects=True)
     raise_for_status(resp)
 
-    _ensure_html_header(resp)
+    _ensure_api_header(resp)
 
 
-def _get_html_response(url: str, session: PipSession) -> Response:
-    """Access an HTML page with GET, and return the response.
+def _get_simple_response(url: str, session: PipSession) -> Response:
+    """Access an Simple API response with GET, and return the response.
 
     This consists of three parts:
 
     1. If the URL looks suspiciously like an archive, send a HEAD first to
-       check the Content-Type is HTML, to avoid downloading a large file.
-       Raise `_NotHTTP` if the content type cannot be determined, or
-       `_NotHTML` if it is not HTML.
+       check the Content-Type is HTML or Simple API, to avoid downloading a
+       large file. Raise `_NotHTTP` if the content type cannot be determined, or
+       `_NotAPIContent` if it is not HTML or a Simple API.
     2. Actually perform the request. Raise HTTP exceptions on network failures.
-    3. Check the Content-Type header to make sure we got HTML, and raise
-       `_NotHTML` otherwise.
+    3. Check the Content-Type header to make sure we got a Simple API response,
+       and raise `_NotAPIContent` otherwise.
     """
     if is_archive_file(Link(url).filename):
-        _ensure_html_response(url, session=session)
+        _ensure_api_response(url, session=session)
 
-    logger.debug('Getting page %s', redact_auth_from_url(url))
+    logger.debug("Getting page %s", redact_auth_from_url(url))
 
     resp = session.get(
         url,
         headers={
-            "Accept": "text/html",
+            "Accept": ", ".join(
+                [
+                    "application/vnd.pypi.simple.v1+json",
+                    "application/vnd.pypi.simple.v1+html; q=0.1",
+                    "text/html; q=0.01",
+                ]
+            ),
             # We don't want to blindly returned cached data for
             # /simple/, because authors generally expecting that
             # twine upload && pip install will function, but if
@@ -137,153 +163,52 @@ def _get_html_response(url: str, session: PipSession) -> Response:
     # The check for archives above only works if the url ends with
     # something that looks like an archive. However that is not a
     # requirement of an url. Unless we issue a HEAD request on every
-    # url we cannot know ahead of time for sure if something is HTML
-    # or not. However we can check after we've downloaded it.
-    _ensure_html_header(resp)
+    # url we cannot know ahead of time for sure if something is a
+    # Simple API response or not. However we can check after we've
+    # downloaded it.
+    _ensure_api_header(resp)
+
+    logger.debug(
+        "Fetched page %s as %s",
+        redact_auth_from_url(url),
+        resp.headers.get("Content-Type", "Unknown"),
+    )
 
     return resp
 
 
 def _get_encoding_from_headers(headers: ResponseHeaders) -> Optional[str]:
-    """Determine if we have any encoding information in our headers.
-    """
+    """Determine if we have any encoding information in our headers."""
     if headers and "Content-Type" in headers:
-        content_type, params = cgi.parse_header(headers["Content-Type"])
-        if "charset" in params:
-            return params['charset']
+        m = email.message.Message()
+        m["content-type"] = headers["Content-Type"]
+        charset = m.get_param("charset")
+        if charset:
+            return str(charset)
     return None
 
 
-def _determine_base_url(document: HTMLElement, page_url: str) -> str:
-    """Determine the HTML document's base URL.
-
-    This looks for a ``<base>`` tag in the HTML document. If present, its href
-    attribute denotes the base URL of anchor tags in the document. If there is
-    no such tag (or if it does not have a valid href attribute), the HTML
-    file's URL is used as the base URL.
-
-    :param document: An HTML document representation. The current
-        implementation expects the result of ``html5lib.parse()``.
-    :param page_url: The URL of the HTML document.
-    """
-    for base in document.findall(".//base"):
-        href = base.get("href")
-        if href is not None:
-            return href
-    return page_url
-
-
-def _clean_url_path_part(part: str) -> str:
-    """
-    Clean a "part" of a URL path (i.e. after splitting on "@" characters).
-    """
-    # We unquote prior to quoting to make sure nothing is double quoted.
-    return urllib.parse.quote(urllib.parse.unquote(part))
-
-
-def _clean_file_url_path(part: str) -> str:
-    """
-    Clean the first part of a URL path that corresponds to a local
-    filesystem path (i.e. the first part after splitting on "@" characters).
-    """
-    # We unquote prior to quoting to make sure nothing is double quoted.
-    # Also, on Windows the path part might contain a drive letter which
-    # should not be quoted. On Linux where drive letters do not
-    # exist, the colon should be quoted. We rely on urllib.request
-    # to do the right thing here.
-    return urllib.request.pathname2url(urllib.request.url2pathname(part))
-
-
-# percent-encoded:                   /
-_reserved_chars_re = re.compile('(@|%2F)', re.IGNORECASE)
-
-
-def _clean_url_path(path: str, is_local_path: bool) -> str:
-    """
-    Clean the path portion of a URL.
-    """
-    if is_local_path:
-        clean_func = _clean_file_url_path
-    else:
-        clean_func = _clean_url_path_part
-
-    # Split on the reserved characters prior to cleaning so that
-    # revision strings in VCS URLs are properly preserved.
-    parts = _reserved_chars_re.split(path)
-
-    cleaned_parts = []
-    for to_clean, reserved in pairwise(itertools.chain(parts, [''])):
-        cleaned_parts.append(clean_func(to_clean))
-        # Normalize %xx escapes (e.g. %2f -> %2F)
-        cleaned_parts.append(reserved.upper())
-
-    return ''.join(cleaned_parts)
-
-
-def _clean_link(url: str) -> str:
-    """
-    Make sure a link is fully quoted.
-    For example, if ' ' occurs in the URL, it will be replaced with "%20",
-    and without double-quoting other characters.
-    """
-    # Split the URL into parts according to the general structure
-    # `scheme://netloc/path;parameters?query#fragment`.
-    result = urllib.parse.urlparse(url)
-    # If the netloc is empty, then the URL refers to a local filesystem path.
-    is_local_path = not result.netloc
-    path = _clean_url_path(result.path, is_local_path=is_local_path)
-    return urllib.parse.urlunparse(result._replace(path=path))
-
-
-def _create_link_from_element(
-    anchor: HTMLElement,
-    page_url: str,
-    base_url: str,
-) -> Optional[Link]:
-    """
-    Convert an anchor element in a simple repository page to a Link.
-    """
-    href = anchor.get("href")
-    if not href:
-        return None
-
-    url = _clean_link(urllib.parse.urljoin(base_url, href))
-    pyrequire = anchor.get('data-requires-python')
-    pyrequire = html.unescape(pyrequire) if pyrequire else None
-
-    yanked_reason = anchor.get('data-yanked')
-    if yanked_reason:
-        yanked_reason = html.unescape(yanked_reason)
-
-    link = Link(
-        url,
-        comes_from=page_url,
-        requires_python=pyrequire,
-        yanked_reason=yanked_reason,
-    )
-
-    return link
-
-
 class CacheablePageContent:
-    def __init__(self, page: "HTMLPage") -> None:
+    def __init__(self, page: "IndexContent") -> None:
         assert page.cache_link_parsing
         self.page = page
 
     def __eq__(self, other: object) -> bool:
-        return (isinstance(other, type(self)) and
-                self.page.url == other.page.url)
+        return isinstance(other, type(self)) and self.page.url == other.page.url
 
     def __hash__(self) -> int:
         return hash(self.page.url)
 
 
-def with_cached_html_pages(
-    fn: Callable[["HTMLPage"], Iterable[Link]],
-) -> Callable[["HTMLPage"], List[Link]]:
+class ParseLinks(Protocol):
+    def __call__(self, page: "IndexContent") -> Iterable[Link]:
+        ...
+
+
+def with_cached_index_content(fn: ParseLinks) -> ParseLinks:
     """
-    Given a function that parses an Iterable[Link] from an HTMLPage, cache the
-    function's result (keyed by CacheablePageContent), unless the HTMLPage
+    Given a function that parses an Iterable[Link] from an IndexContent, cache the
+    function's result (keyed by CacheablePageContent), unless the IndexContent
     `page` has `page.cache_link_parsing == False`.
     """
 
@@ -292,7 +217,7 @@ def with_cached_html_pages(
         return list(fn(cacheable_page.page))
 
     @functools.wraps(fn)
-    def wrapper_wrapper(page: "HTMLPage") -> List[Link]:
+    def wrapper_wrapper(page: "IndexContent") -> List[Link]:
         if page.cache_link_parsing:
             return wrapper(CacheablePageContent(page))
         return list(fn(page))
@@ -300,36 +225,42 @@ def with_cached_html_pages(
     return wrapper_wrapper
 
 
-@with_cached_html_pages
-def parse_links(page: "HTMLPage") -> Iterable[Link]:
+@with_cached_index_content
+def parse_links(page: "IndexContent") -> Iterable[Link]:
     """
-    Parse an HTML document, and yield its anchor elements as Link objects.
+    Parse a Simple API's Index Content, and yield its anchor elements as Link objects.
     """
-    document = html5lib.parse(
-        page.content,
-        transport_encoding=page.encoding,
-        namespaceHTMLElements=False,
-    )
+
+    content_type_l = page.content_type.lower()
+    if content_type_l.startswith("application/vnd.pypi.simple.v1+json"):
+        data = json.loads(page.content)
+        for file in data.get("files", []):
+            link = Link.from_json(file, page.url)
+            if link is None:
+                continue
+            yield link
+        return
+
+    parser = HTMLLinkParser(page.url)
+    encoding = page.encoding or "utf-8"
+    parser.feed(page.content.decode(encoding))
 
     url = page.url
-    base_url = _determine_base_url(document, url)
-    for anchor in document.findall(".//a"):
-        link = _create_link_from_element(
-            anchor,
-            page_url=url,
-            base_url=base_url,
-        )
+    base_url = parser.base_url or url
+    for anchor in parser.anchors:
+        link = Link.from_element(anchor, page_url=url, base_url=base_url)
         if link is None:
             continue
         yield link
 
 
-class HTMLPage:
-    """Represents one page, along with its URL"""
+class IndexContent:
+    """Represents one response (or page), along with its URL"""
 
     def __init__(
         self,
         content: bytes,
+        content_type: str,
         encoding: Optional[str],
         url: str,
         cache_link_parsing: bool = True,
@@ -342,6 +273,7 @@ class HTMLPage:
                                    have this set to False, for example.
         """
         self.content = content
+        self.content_type = content_type
         self.encoding = encoding
         self.url = url
         self.cache_link_parsing = cache_link_parsing
@@ -350,80 +282,115 @@ class HTMLPage:
         return redact_auth_from_url(self.url)
 
 
-def _handle_get_page_fail(
+class HTMLLinkParser(HTMLParser):
+    """
+    HTMLParser that keeps the first base HREF and a list of all anchor
+    elements' attributes.
+    """
+
+    def __init__(self, url: str) -> None:
+        super().__init__(convert_charrefs=True)
+
+        self.url: str = url
+        self.base_url: Optional[str] = None
+        self.anchors: List[Dict[str, Optional[str]]] = []
+
+    def handle_starttag(self, tag: str, attrs: List[Tuple[str, Optional[str]]]) -> None:
+        if tag == "base" and self.base_url is None:
+            href = self.get_href(attrs)
+            if href is not None:
+                self.base_url = href
+        elif tag == "a":
+            self.anchors.append(dict(attrs))
+
+    def get_href(self, attrs: List[Tuple[str, Optional[str]]]) -> Optional[str]:
+        for name, value in attrs:
+            if name == "href":
+                return value
+        return None
+
+
+def _handle_get_simple_fail(
     link: Link,
     reason: Union[str, Exception],
-    meth: Optional[Callable[..., None]] = None
+    meth: Optional[Callable[..., None]] = None,
 ) -> None:
     if meth is None:
         meth = logger.debug
     meth("Could not fetch URL %s: %s - skipping", link, reason)
 
 
-def _make_html_page(response: Response, cache_link_parsing: bool = True) -> HTMLPage:
+def _make_index_content(
+    response: Response, cache_link_parsing: bool = True
+) -> IndexContent:
     encoding = _get_encoding_from_headers(response.headers)
-    return HTMLPage(
+    return IndexContent(
         response.content,
+        response.headers["Content-Type"],
         encoding=encoding,
         url=response.url,
-        cache_link_parsing=cache_link_parsing)
+        cache_link_parsing=cache_link_parsing,
+    )
 
 
-def _get_html_page(
-    link: Link, session: Optional[PipSession] = None
-) -> Optional["HTMLPage"]:
-    if session is None:
-        raise TypeError(
-            "_get_html_page() missing 1 required keyword argument: 'session'"
-        )
-
-    url = link.url.split('#', 1)[0]
+def _get_index_content(link: Link, *, session: PipSession) -> Optional["IndexContent"]:
+    url = link.url.split("#", 1)[0]
 
     # Check for VCS schemes that do not support lookup as web pages.
     vcs_scheme = _match_vcs_scheme(url)
     if vcs_scheme:
-        logger.warning('Cannot look at %s URL %s because it does not support '
-                       'lookup as web pages.', vcs_scheme, link)
+        logger.warning(
+            "Cannot look at %s URL %s because it does not support lookup as web pages.",
+            vcs_scheme,
+            link,
+        )
         return None
 
     # Tack index.html onto file:// URLs that point to directories
     scheme, _, path, _, _, _ = urllib.parse.urlparse(url)
-    if (scheme == 'file' and os.path.isdir(urllib.request.url2pathname(path))):
+    if scheme == "file" and os.path.isdir(urllib.request.url2pathname(path)):
         # add trailing slash if not present so urljoin doesn't trim
         # final segment
-        if not url.endswith('/'):
-            url += '/'
-        url = urllib.parse.urljoin(url, 'index.html')
-        logger.debug(' file: URL is directory, getting %s', url)
+        if not url.endswith("/"):
+            url += "/"
+        # TODO: In the future, it would be nice if pip supported PEP 691
+        #       style responses in the file:// URLs, however there's no
+        #       standard file extension for application/vnd.pypi.simple.v1+json
+        #       so we'll need to come up with something on our own.
+        url = urllib.parse.urljoin(url, "index.html")
+        logger.debug(" file: URL is directory, getting %s", url)
 
     try:
-        resp = _get_html_response(url, session=session)
+        resp = _get_simple_response(url, session=session)
     except _NotHTTP:
         logger.warning(
-            'Skipping page %s because it looks like an archive, and cannot '
-            'be checked by a HTTP HEAD request.', link,
+            "Skipping page %s because it looks like an archive, and cannot "
+            "be checked by a HTTP HEAD request.",
+            link,
         )
-    except _NotHTML as exc:
+    except _NotAPIContent as exc:
         logger.warning(
-            'Skipping page %s because the %s request got Content-Type: %s.'
-            'The only supported Content-Type is text/html',
-            link, exc.request_desc, exc.content_type,
+            "Skipping page %s because the %s request got Content-Type: %s. "
+            "The only supported Content-Types are application/vnd.pypi.simple.v1+json, "
+            "application/vnd.pypi.simple.v1+html, and text/html",
+            link,
+            exc.request_desc,
+            exc.content_type,
         )
     except NetworkConnectionError as exc:
-        _handle_get_page_fail(link, exc)
+        _handle_get_simple_fail(link, exc)
     except RetryError as exc:
-        _handle_get_page_fail(link, exc)
+        _handle_get_simple_fail(link, exc)
     except SSLError as exc:
         reason = "There was a problem confirming the ssl certificate: "
         reason += str(exc)
-        _handle_get_page_fail(link, reason, meth=logger.info)
+        _handle_get_simple_fail(link, reason, meth=logger.info)
     except requests.ConnectionError as exc:
-        _handle_get_page_fail(link, f"connection error: {exc}")
+        _handle_get_simple_fail(link, f"connection error: {exc}")
     except requests.Timeout:
-        _handle_get_page_fail(link, "timed out")
+        _handle_get_simple_fail(link, "timed out")
     else:
-        return _make_html_page(resp,
-                               cache_link_parsing=link.cache_link_parsing)
+        return _make_index_content(resp, cache_link_parsing=link.cache_link_parsing)
     return None
 
 
@@ -451,9 +418,10 @@ class LinkCollector:
 
     @classmethod
     def create(
-        cls, session: PipSession,
+        cls,
+        session: PipSession,
         options: Values,
-        suppress_no_index: bool = False
+        suppress_no_index: bool = False,
     ) -> "LinkCollector":
         """
         :param session: The Session to use to make requests.
@@ -463,8 +431,8 @@ class LinkCollector:
         index_urls = [options.index_url] + options.extra_index_urls
         if options.no_index and not suppress_no_index:
             logger.debug(
-                'Ignoring indexes: %s',
-                ','.join(redact_auth_from_url(url) for url in index_urls),
+                "Ignoring indexes: %s",
+                ",".join(redact_auth_from_url(url) for url in index_urls),
             )
             index_urls = []
 
@@ -472,10 +440,13 @@ class LinkCollector:
         find_links = options.find_links or []
 
         search_scope = SearchScope.create(
-            find_links=find_links, index_urls=index_urls,
+            find_links=find_links,
+            index_urls=index_urls,
+            no_index=options.no_index,
         )
         link_collector = LinkCollector(
-            session=session, search_scope=search_scope,
+            session=session,
+            search_scope=search_scope,
         )
         return link_collector
 
@@ -483,11 +454,11 @@ class LinkCollector:
     def find_links(self) -> List[str]:
         return self.search_scope.find_links
 
-    def fetch_page(self, location: Link) -> Optional[HTMLPage]:
+    def fetch_response(self, location: Link) -> Optional[IndexContent]:
         """
         Fetch an HTML page containing package links.
         """
-        return _get_html_page(location, session=self.session)
+        return _get_index_content(location, session=self.session)
 
     def collect_sources(
         self,

venv/Lib/site-packages/pip/_internal/index/package_finder.py

@@ -1,13 +1,11 @@
 """Routines related to PyPI, indexes"""
 
-# The following comment should be removed at some point in the future.
-# mypy: strict-optional=False
-
+import enum
 import functools
 import itertools
 import logging
 import re
-from typing import FrozenSet, Iterable, List, Optional, Set, Tuple, Union
+from typing import TYPE_CHECKING, FrozenSet, Iterable, List, Optional, Set, Tuple, Union
 
 from pip._vendor.packaging import specifiers
 from pip._vendor.packaging.tags import Tag
@@ -37,17 +35,17 @@ from pip._internal.utils.logging import indent_log
 from pip._internal.utils.misc import build_netloc
 from pip._internal.utils.packaging import check_requires_python
 from pip._internal.utils.unpacking import SUPPORTED_EXTENSIONS
-from pip._internal.utils.urls import url_to_path
 
-__all__ = ['FormatControl', 'BestCandidateResult', 'PackageFinder']
+if TYPE_CHECKING:
+    from pip._vendor.typing_extensions import TypeGuard
+
+__all__ = ["FormatControl", "BestCandidateResult", "PackageFinder"]
 
 
 logger = getLogger(__name__)
 
 BuildTag = Union[Tuple[()], Tuple[int, str]]
-CandidateSortingKey = (
-    Tuple[int, int, int, _BaseVersion, Optional[int], BuildTag]
-)
+CandidateSortingKey = Tuple[int, int, int, _BaseVersion, Optional[int], BuildTag]
 
 
 def _check_link_requires_python(
@@ -66,39 +64,54 @@ def _check_link_requires_python(
     """
     try:
         is_compatible = check_requires_python(
-            link.requires_python, version_info=version_info,
+            link.requires_python,
+            version_info=version_info,
         )
     except specifiers.InvalidSpecifier:
         logger.debug(
             "Ignoring invalid Requires-Python (%r) for link: %s",
-            link.requires_python, link,
+            link.requires_python,
+            link,
         )
     else:
         if not is_compatible:
-            version = '.'.join(map(str, version_info))
+            version = ".".join(map(str, version_info))
             if not ignore_requires_python:
                 logger.verbose(
-                    'Link requires a different Python (%s not in: %r): %s',
-                    version, link.requires_python, link,
+                    "Link requires a different Python (%s not in: %r): %s",
+                    version,
+                    link.requires_python,
+                    link,
                 )
                 return False
 
             logger.debug(
-                'Ignoring failed Requires-Python check (%s not in: %r) '
-                'for link: %s',
-                version, link.requires_python, link,
+                "Ignoring failed Requires-Python check (%s not in: %r) for link: %s",
+                version,
+                link.requires_python,
+                link,
             )
 
     return True
 
 
+class LinkType(enum.Enum):
+    candidate = enum.auto()
+    different_project = enum.auto()
+    yanked = enum.auto()
+    format_unsupported = enum.auto()
+    format_invalid = enum.auto()
+    platform_mismatch = enum.auto()
+    requires_python_mismatch = enum.auto()
+
+
 class LinkEvaluator:
 
     """
     Responsible for evaluating links for a particular project.
     """
 
-    _py_version_re = re.compile(r'-py([123]\.?[0-9]?)$')
+    _py_version_re = re.compile(r"-py([123]\.?[0-9]?)$")
 
     # Don't include an allow_yanked default value to make sure each call
     # site considers whether yanked releases are allowed. This also causes
@@ -141,19 +154,20 @@ class LinkEvaluator:
 
         self.project_name = project_name
 
-    def evaluate_link(self, link: Link) -> Tuple[bool, Optional[str]]:
+    def evaluate_link(self, link: Link) -> Tuple[LinkType, str]:
         """
         Determine whether a link is a candidate for installation.
 
-        :return: A tuple (is_candidate, result), where `result` is (1) a
-            version string if `is_candidate` is True, and (2) if
-            `is_candidate` is False, an optional string to log the reason
-            the link fails to qualify.
+        :return: A tuple (result, detail), where *result* is an enum
+            representing whether the evaluation found a candidate, or the reason
+            why one is not found. If a candidate is found, *detail* will be the
+            candidate's version string; if one is not found, it contains the
+            reason the link fails to qualify.
         """
         version = None
         if link.is_yanked and not self._allow_yanked:
-            reason = link.yanked_reason or '<none given>'
-            return (False, f'yanked for reason: {reason}')
+            reason = link.yanked_reason or "<none given>"
+            return (LinkType.yanked, f"yanked for reason: {reason}")
 
         if link.egg_fragment:
             egg_info = link.egg_fragment
@@ -161,77 +175,83 @@ class LinkEvaluator:
         else:
             egg_info, ext = link.splitext()
             if not ext:
-                return (False, 'not a file')
+                return (LinkType.format_unsupported, "not a file")
             if ext not in SUPPORTED_EXTENSIONS:
-                return (False, f'unsupported archive format: {ext}')
+                return (
+                    LinkType.format_unsupported,
+                    f"unsupported archive format: {ext}",
+                )
             if "binary" not in self._formats and ext == WHEEL_EXTENSION:
-                reason = 'No binaries permitted for {}'.format(
-                    self.project_name)
-                return (False, reason)
-            if "macosx10" in link.path and ext == '.zip':
-                return (False, 'macosx10 one')
+                reason = f"No binaries permitted for {self.project_name}"
+                return (LinkType.format_unsupported, reason)
+            if "macosx10" in link.path and ext == ".zip":
+                return (LinkType.format_unsupported, "macosx10 one")
             if ext == WHEEL_EXTENSION:
                 try:
                     wheel = Wheel(link.filename)
                 except InvalidWheelFilename:
-                    return (False, 'invalid wheel filename')
+                    return (
+                        LinkType.format_invalid,
+                        "invalid wheel filename",
+                    )
                 if canonicalize_name(wheel.name) != self._canonical_name:
-                    reason = 'wrong project name (not {})'.format(
-                        self.project_name)
-                    return (False, reason)
+                    reason = f"wrong project name (not {self.project_name})"
+                    return (LinkType.different_project, reason)
 
                 supported_tags = self._target_python.get_tags()
                 if not wheel.supported(supported_tags):
                     # Include the wheel's tags in the reason string to
                     # simplify troubleshooting compatibility issues.
-                    file_tags = wheel.get_formatted_file_tags()
+                    file_tags = ", ".join(wheel.get_formatted_file_tags())
                     reason = (
-                        "none of the wheel's tags ({}) are compatible "
-                        "(run pip debug --verbose to show compatible tags)".format(
-                            ', '.join(file_tags)
-                        )
+                        f"none of the wheel's tags ({file_tags}) are compatible "
+                        f"(run pip debug --verbose to show compatible tags)"
                     )
-                    return (False, reason)
+                    return (LinkType.platform_mismatch, reason)
 
                 version = wheel.version
 
         # This should be up by the self.ok_binary check, but see issue 2700.
         if "source" not in self._formats and ext != WHEEL_EXTENSION:
-            reason = f'No sources permitted for {self.project_name}'
-            return (False, reason)
+            reason = f"No sources permitted for {self.project_name}"
+            return (LinkType.format_unsupported, reason)
 
         if not version:
             version = _extract_version_from_fragment(
-                egg_info, self._canonical_name,
+                egg_info,
+                self._canonical_name,
             )
         if not version:
-            reason = f'Missing project version for {self.project_name}'
-            return (False, reason)
+            reason = f"Missing project version for {self.project_name}"
+            return (LinkType.format_invalid, reason)
 
         match = self._py_version_re.search(version)
         if match:
-            version = version[:match.start()]
+            version = version[: match.start()]
             py_version = match.group(1)
             if py_version != self._target_python.py_version:
-                return (False, 'Python version is incorrect')
+                return (
+                    LinkType.platform_mismatch,
+                    "Python version is incorrect",
+                )
 
         supports_python = _check_link_requires_python(
-            link, version_info=self._target_python.py_version_info,
+            link,
+            version_info=self._target_python.py_version_info,
             ignore_requires_python=self._ignore_requires_python,
         )
         if not supports_python:
-            # Return None for the reason text to suppress calling
-            # _log_skipped_link().
-            return (False, None)
+            reason = f"{version} Requires-Python {link.requires_python}"
+            return (LinkType.requires_python_mismatch, reason)
 
-        logger.debug('Found link %s, version: %s', link, version)
+        logger.debug("Found link %s, version: %s", link, version)
 
-        return (True, version)
+        return (LinkType.candidate, version)
 
 
 def filter_unallowed_hashes(
     candidates: List[InstallationCandidate],
-    hashes: Hashes,
+    hashes: Optional[Hashes],
     project_name: str,
 ) -> List[InstallationCandidate]:
     """
@@ -251,8 +271,8 @@ def filter_unallowed_hashes(
     """
     if not hashes:
         logger.debug(
-            'Given no hashes to check %s links for project %r: '
-            'discarding no candidates',
+            "Given no hashes to check %s links for project %r: "
+            "discarding no candidates",
             len(candidates),
             project_name,
         )
@@ -282,22 +302,22 @@ def filter_unallowed_hashes(
         filtered = list(candidates)
 
     if len(filtered) == len(candidates):
-        discard_message = 'discarding no candidates'
+        discard_message = "discarding no candidates"
     else:
-        discard_message = 'discarding {} non-matches:\n  {}'.format(
+        discard_message = "discarding {} non-matches:\n  {}".format(
             len(non_matches),
-            '\n  '.join(str(candidate.link) for candidate in non_matches)
+            "\n  ".join(str(candidate.link) for candidate in non_matches),
         )
 
     logger.debug(
-        'Checked %s links for project %r against %s hashes '
-        '(%s matches, %s no digest): %s',
+        "Checked %s links for project %r against %s hashes "
+        "(%s matches, %s no digest): %s",
         len(candidates),
         project_name,
         hashes.digest_count,
         match_count,
         len(matches_or_no_digest) - match_count,
-        discard_message
+        discard_message,
     )
 
     return filtered
@@ -354,13 +374,11 @@ class BestCandidateResult:
         self.best_candidate = best_candidate
 
     def iter_all(self) -> Iterable[InstallationCandidate]:
-        """Iterate through all candidates.
-        """
+        """Iterate through all candidates."""
         return iter(self._candidates)
 
     def iter_applicable(self) -> Iterable[InstallationCandidate]:
-        """Iterate through the applicable candidates.
-        """
+        """Iterate through the applicable candidates."""
         return iter(self._applicable_candidates)
 
 
@@ -444,7 +462,8 @@ class CandidateEvaluator:
         allow_prereleases = self._allow_all_prereleases or None
         specifier = self._specifier
         versions = {
-            str(v) for v in specifier.filter(
+            str(v)
+            for v in specifier.filter(
                 # We turn the version object into a str here because otherwise
                 # when we're debundled but setuptools isn't, Python will see
                 # packaging.version.Version and
@@ -458,9 +477,7 @@ class CandidateEvaluator:
         }
 
         # Again, converting version to str to deal with debundling.
-        applicable_candidates = [
-            c for c in candidates if str(c.version) in versions
-        ]
+        applicable_candidates = [c for c in candidates if str(c.version) in versions]
 
         filtered_applicable_candidates = filter_unallowed_hashes(
             candidates=applicable_candidates,
@@ -509,9 +526,11 @@ class CandidateEvaluator:
             # can raise InvalidWheelFilename
             wheel = Wheel(link.filename)
             try:
-                pri = -(wheel.find_most_preferred_tag(
-                    valid_tags, self._wheel_tag_preferences
-                ))
+                pri = -(
+                    wheel.find_most_preferred_tag(
+                        valid_tags, self._wheel_tag_preferences
+                    )
+                )
             except ValueError:
                 raise UnsupportedWheel(
                     "{} is not a supported wheel for this platform. It "
@@ -520,7 +539,8 @@ class CandidateEvaluator:
             if self._prefer_binary:
                 binary_preference = 1
             if wheel.build_tag is not None:
-                match = re.match(r'^(\d+)(.*)$', wheel.build_tag)
+                match = re.match(r"^(\d+)(.*)$", wheel.build_tag)
+                assert match is not None, "guaranteed by filename validation"
                 build_tag_groups = match.groups()
                 build_tag = (int(build_tag_groups[0]), build_tag_groups[1])
         else:  # sdist
@@ -528,8 +548,12 @@ class CandidateEvaluator:
         has_allowed_hash = int(link.is_hash_allowed(self._hashes))
         yank_value = -1 * int(link.is_yanked)  # -1 for yanked.
         return (
-            has_allowed_hash, yank_value, binary_preference, candidate.version,
-            pri, build_tag,
+            has_allowed_hash,
+            yank_value,
+            binary_preference,
+            candidate.version,
+            pri,
+            build_tag,
         )
 
     def sort_best_candidate(
@@ -603,7 +627,7 @@ class PackageFinder:
         self.format_control = format_control
 
         # These are boring links that have already been logged somehow.
-        self._logged_links: Set[Link] = set()
+        self._logged_links: Set[Tuple[Link, LinkType, str]] = set()
 
     # Don't include an allow_yanked default value to make sure each call
     # site considers whether yanked releases are allowed. This also causes
@@ -680,6 +704,14 @@ class PackageFinder:
     def set_prefer_binary(self) -> None:
         self._candidate_prefs.prefer_binary = True
 
+    def requires_python_skipped_reasons(self) -> List[str]:
+        reasons = {
+            detail
+            for _, result, detail in self._logged_links
+            if result == LinkType.requires_python_mismatch
+        }
+        return sorted(reasons)
+
     def make_link_evaluator(self, project_name: str) -> LinkEvaluator:
         canonical_name = canonicalize_name(project_name)
         formats = self.format_control.get_allowed_formats(canonical_name)
@@ -709,12 +741,13 @@ class PackageFinder:
                     no_eggs.append(link)
         return no_eggs + eggs
 
-    def _log_skipped_link(self, link: Link, reason: str) -> None:
-        if link not in self._logged_links:
+    def _log_skipped_link(self, link: Link, result: LinkType, detail: str) -> None:
+        entry = (link, result, detail)
+        if entry not in self._logged_links:
             # Put the link at the end so the reason is more visible and because
             # the link string is usually very long.
-            logger.debug('Skipping link: %s: %s', reason, link)
-            self._logged_links.add(link)
+            logger.debug("Skipping link: %s: %s", detail, link)
+            self._logged_links.add(entry)
 
     def get_install_candidate(
         self, link_evaluator: LinkEvaluator, link: Link
@@ -723,16 +756,15 @@ class PackageFinder:
         If the link is a candidate for install, convert it to an
         InstallationCandidate and return it. Otherwise, return None.
         """
-        is_candidate, result = link_evaluator.evaluate_link(link)
-        if not is_candidate:
-            if result:
-                self._log_skipped_link(link, reason=result)
+        result, detail = link_evaluator.evaluate_link(link)
+        if result != LinkType.candidate:
+            self._log_skipped_link(link, result, detail)
             return None
 
         return InstallationCandidate(
             name=link_evaluator.project_name,
             link=link,
-            version=result,
+            version=detail,
         )
 
     def evaluate_links(
@@ -753,13 +785,14 @@ class PackageFinder:
         self, project_url: Link, link_evaluator: LinkEvaluator
     ) -> List[InstallationCandidate]:
         logger.debug(
-            'Fetching project page and analyzing links: %s', project_url,
+            "Fetching project page and analyzing links: %s",
+            project_url,
         )
-        html_page = self._link_collector.fetch_page(project_url)
-        if html_page is None:
+        index_response = self._link_collector.fetch_response(project_url)
+        if index_response is None:
             return []
 
-        page_links = list(parse_links(html_page))
+        page_links = list(parse_links(index_response))
 
         with indent_log():
             package_links = self.evaluate_links(
@@ -809,7 +842,14 @@ class PackageFinder:
         )
 
         if logger.isEnabledFor(logging.DEBUG) and file_candidates:
-            paths = [url_to_path(c.link.url) for c in file_candidates]
+            paths = []
+            for candidate in file_candidates:
+                assert candidate.link.url  # we need to have a URL
+                try:
+                    paths.append(candidate.link.file_path)
+                except Exception:
+                    paths.append(candidate.link.url)  # it's not a local file
+
             logger.debug("Local files found: %s", ", ".join(paths))
 
         # This is an intentional priority ordering
@@ -821,8 +861,7 @@ class PackageFinder:
         specifier: Optional[specifiers.BaseSpecifier] = None,
         hashes: Optional[Hashes] = None,
     ) -> CandidateEvaluator:
-        """Create a CandidateEvaluator object to use.
-        """
+        """Create a CandidateEvaluator object to use."""
         candidate_prefs = self._candidate_prefs
         return CandidateEvaluator.create(
             project_name=project_name,
@@ -867,75 +906,83 @@ class PackageFinder:
         """
         hashes = req.hashes(trust_internet=False)
         best_candidate_result = self.find_best_candidate(
-            req.name, specifier=req.specifier, hashes=hashes,
+            req.name,
+            specifier=req.specifier,
+            hashes=hashes,
         )
         best_candidate = best_candidate_result.best_candidate
 
         installed_version: Optional[_BaseVersion] = None
         if req.satisfied_by is not None:
-            installed_version = parse_version(req.satisfied_by.version)
+            installed_version = req.satisfied_by.version
 
         def _format_versions(cand_iter: Iterable[InstallationCandidate]) -> str:
             # This repeated parse_version and str() conversion is needed to
             # handle different vendoring sources from pip and pkg_resources.
             # If we stop using the pkg_resources provided specifier and start
             # using our own, we can drop the cast to str().
-            return ", ".join(sorted(
-                {str(c.version) for c in cand_iter},
-                key=parse_version,
-            )) or "none"
+            return (
+                ", ".join(
+                    sorted(
+                        {str(c.version) for c in cand_iter},
+                        key=parse_version,
+                    )
+                )
+                or "none"
+            )
 
         if installed_version is None and best_candidate is None:
             logger.critical(
-                'Could not find a version that satisfies the requirement %s '
-                '(from versions: %s)',
+                "Could not find a version that satisfies the requirement %s "
+                "(from versions: %s)",
                 req,
                 _format_versions(best_candidate_result.iter_all()),
             )
 
             raise DistributionNotFound(
-                'No matching distribution found for {}'.format(
-                    req)
+                "No matching distribution found for {}".format(req)
             )
 
-        best_installed = False
-        if installed_version and (
-                best_candidate is None or
-                best_candidate.version <= installed_version):
-            best_installed = True
+        def _should_install_candidate(
+            candidate: Optional[InstallationCandidate],
+        ) -> "TypeGuard[InstallationCandidate]":
+            if installed_version is None:
+                return True
+            if best_candidate is None:
+                return False
+            return best_candidate.version > installed_version
 
         if not upgrade and installed_version is not None:
-            if best_installed:
+            if _should_install_candidate(best_candidate):
                 logger.debug(
-                    'Existing installed version (%s) is most up-to-date and '
-                    'satisfies requirement',
-                    installed_version,
-                )
-            else:
-                logger.debug(
-                    'Existing installed version (%s) satisfies requirement '
-                    '(most up-to-date version is %s)',
+                    "Existing installed version (%s) satisfies requirement "
+                    "(most up-to-date version is %s)",
                     installed_version,
                     best_candidate.version,
                 )
+            else:
+                logger.debug(
+                    "Existing installed version (%s) is most up-to-date and "
+                    "satisfies requirement",
+                    installed_version,
+                )
             return None
 
-        if best_installed:
-            # We have an existing version, and its the best version
+        if _should_install_candidate(best_candidate):
             logger.debug(
-                'Installed version (%s) is most up-to-date (past versions: '
-                '%s)',
-                installed_version,
+                "Using version %s (newest of versions: %s)",
+                best_candidate.version,
                 _format_versions(best_candidate_result.iter_applicable()),
             )
-            raise BestVersionAlreadyInstalled
+            return best_candidate
 
+        # We have an existing version, and its the best version
         logger.debug(
-            'Using version %s (newest of versions: %s)',
-            best_candidate.version,
+            "Installed version (%s) is most up-to-date (past versions: %s)",
+            installed_version,
             _format_versions(best_candidate_result.iter_applicable()),
         )
-        return best_candidate
+        raise BestVersionAlreadyInstalled
 
 
 def _find_name_version_sep(fragment: str, canonical_name: str) -> int:

venv/Lib/site-packages/pip/_internal/index/sources.py

@@ -171,7 +171,6 @@ def build_source(
     expand_dir: bool,
     cache_link_parsing: bool,
 ) -> Tuple[Optional[str], Optional[LinkSource]]:
-
     path: Optional[str] = None
     url: Optional[str] = None
     if os.path.exists(location):  # Is a local path.

venv/Lib/site-packages/pip/_internal/locations/__init__.py

@@ -4,14 +4,14 @@ import os
 import pathlib
 import sys
 import sysconfig
-from typing import Any, Dict, Iterator, List, Optional, Tuple
+from typing import Any, Dict, Generator, Optional, Tuple
 
 from pip._internal.models.scheme import SCHEME_KEYS, Scheme
 from pip._internal.utils.compat import WINDOWS
 from pip._internal.utils.deprecation import deprecated
 from pip._internal.utils.virtualenv import running_under_virtualenv
 
-from . import _distutils, _sysconfig
+from . import _sysconfig
 from .base import (
     USER_CACHE_DIR,
     get_major_minor_version,
@@ -27,7 +27,6 @@ __all__ = [
     "get_bin_user",
     "get_major_minor_version",
     "get_platlib",
-    "get_prefixed_libs",
     "get_purelib",
     "get_scheme",
     "get_src_prefix",
@@ -38,20 +37,48 @@ __all__ = [
 
 logger = logging.getLogger(__name__)
 
-if os.environ.get("_PIP_LOCATIONS_NO_WARN_ON_MISMATCH"):
-    _MISMATCH_LEVEL = logging.DEBUG
-else:
-    _MISMATCH_LEVEL = logging.WARNING
 
 _PLATLIBDIR: str = getattr(sys, "platlibdir", "lib")
 
+_USE_SYSCONFIG_DEFAULT = sys.version_info >= (3, 10)
+
+
+def _should_use_sysconfig() -> bool:
+    """This function determines the value of _USE_SYSCONFIG.
+
+    By default, pip uses sysconfig on Python 3.10+.
+    But Python distributors can override this decision by setting:
+        sysconfig._PIP_USE_SYSCONFIG = True / False
+    Rationale in https://github.com/pypa/pip/issues/10647
+
+    This is a function for testability, but should be constant during any one
+    run.
+    """
+    return bool(getattr(sysconfig, "_PIP_USE_SYSCONFIG", _USE_SYSCONFIG_DEFAULT))
+
+
+_USE_SYSCONFIG = _should_use_sysconfig()
+
+if not _USE_SYSCONFIG:
+    # Import distutils lazily to avoid deprecation warnings,
+    # but import it soon enough that it is in memory and available during
+    # a pip reinstall.
+    from . import _distutils
+
+# Be noisy about incompatibilities if this platforms "should" be using
+# sysconfig, but is explicitly opting out and using distutils instead.
+if _USE_SYSCONFIG_DEFAULT and not _USE_SYSCONFIG:
+    _MISMATCH_LEVEL = logging.WARNING
+else:
+    _MISMATCH_LEVEL = logging.DEBUG
+
 
 def _looks_like_bpo_44860() -> bool:
     """The resolution to bpo-44860 will change this incorrect platlib.
 
     See <https://bugs.python.org/issue44860>.
     """
-    from distutils.command.install import INSTALL_SCHEMES  # type: ignore
+    from distutils.command.install import INSTALL_SCHEMES
 
     try:
         unix_user_platlib = INSTALL_SCHEMES["unix_user"]["platlib"]
@@ -62,6 +89,8 @@ def _looks_like_bpo_44860() -> bool:
 
 def _looks_like_red_hat_patched_platlib_purelib(scheme: Dict[str, str]) -> bool:
     platlib = scheme["platlib"]
+    if "/$platlibdir/" in platlib:
+        platlib = platlib.replace("/$platlibdir/", f"/{_PLATLIBDIR}/")
     if "/lib64/" not in platlib:
         return False
     unpatched = platlib.replace("/lib64/", "/lib/")
@@ -74,7 +103,7 @@ def _looks_like_red_hat_lib() -> bool:
 
     This is the only way I can see to tell a Red Hat-patched Python.
     """
-    from distutils.command.install import INSTALL_SCHEMES  # type: ignore
+    from distutils.command.install import INSTALL_SCHEMES
 
     return all(
         k in INSTALL_SCHEMES
@@ -86,7 +115,7 @@ def _looks_like_red_hat_lib() -> bool:
 @functools.lru_cache(maxsize=None)
 def _looks_like_debian_scheme() -> bool:
     """Debian adds two additional schemes."""
-    from distutils.command.install import INSTALL_SCHEMES  # type: ignore
+    from distutils.command.install import INSTALL_SCHEMES
 
     return "deb_system" in INSTALL_SCHEMES and "unix_local" in INSTALL_SCHEMES
 
@@ -111,6 +140,22 @@ def _looks_like_red_hat_scheme() -> bool:
     )
 
 
+@functools.lru_cache(maxsize=None)
+def _looks_like_slackware_scheme() -> bool:
+    """Slackware patches sysconfig but fails to patch distutils and site.
+
+    Slackware changes sysconfig's user scheme to use ``"lib64"`` for the lib
+    path, but does not do the same to the site module.
+    """
+    if user_site is None:  # User-site not available.
+        return False
+    try:
+        paths = sysconfig.get_paths(scheme="posix_user", expand=False)
+    except KeyError:  # User-site not available.
+        return False
+    return "/lib64/" in paths["purelib"] and "/lib64/" not in user_site
+
+
 @functools.lru_cache(maxsize=None)
 def _looks_like_msys2_mingw_scheme() -> bool:
     """MSYS2 patches distutils and sysconfig to use a UNIX-like scheme.
@@ -129,9 +174,9 @@ def _looks_like_msys2_mingw_scheme() -> bool:
     )
 
 
-def _fix_abiflags(parts: Tuple[str]) -> Iterator[str]:
+def _fix_abiflags(parts: Tuple[str]) -> Generator[str, None, None]:
     ldversion = sysconfig.get_config_var("LDVERSION")
-    abiflags: str = getattr(sys, "abiflags", None)
+    abiflags = getattr(sys, "abiflags", None)
 
     # LDVERSION does not end with sys.abiflags. Just return the path unchanged.
     if not ldversion or not abiflags or not ldversion.endswith(abiflags):
@@ -190,7 +235,7 @@ def get_scheme(
     isolated: bool = False,
     prefix: Optional[str] = None,
 ) -> Scheme:
-    old = _distutils.get_scheme(
+    new = _sysconfig.get_scheme(
         dist_name,
         user=user,
         home=home,
@@ -198,7 +243,10 @@ def get_scheme(
         isolated=isolated,
         prefix=prefix,
     )
-    new = _sysconfig.get_scheme(
+    if _USE_SYSCONFIG:
+        return new
+
+    old = _distutils.get_scheme(
         dist_name,
         user=user,
         home=home,
@@ -263,6 +311,17 @@ def get_scheme(
         if skip_bpo_44860:
             continue
 
+        # Slackware incorrectly patches posix_user to use lib64 instead of lib,
+        # but not usersite to match the location.
+        skip_slackware_user_scheme = (
+            user
+            and k in ("platlib", "purelib")
+            and not WINDOWS
+            and _looks_like_slackware_scheme()
+        )
+        if skip_slackware_user_scheme:
+            continue
+
         # Both Debian and Red Hat patch Python to place the system site under
         # /usr/local instead of /usr. Debian also places lib in dist-packages
         # instead of site-packages, but the /usr/local check should cover it.
@@ -296,6 +355,18 @@ def get_scheme(
         if skip_msys2_mingw_bug:
             continue
 
+        # CPython's POSIX install script invokes pip (via ensurepip) against the
+        # interpreter located in the source tree, not the install site. This
+        # triggers special logic in sysconfig that's not present in distutils.
+        # https://github.com/python/cpython/blob/8c21941ddaf/Lib/sysconfig.py#L178-L194
+        skip_cpython_build = (
+            sysconfig.is_python_build(check_home=True)
+            and not WINDOWS
+            and k in ("headers", "include", "platinclude")
+        )
+        if skip_cpython_build:
+            continue
+
         warning_contexts.append((old_v, new_v, f"scheme.{k}"))
 
     if not warning_contexts:
@@ -315,10 +386,12 @@ def get_scheme(
     )
     if any(default_old[k] != getattr(old, k) for k in SCHEME_KEYS):
         deprecated(
-            "Configuring installation scheme with distutils config files "
-            "is deprecated and will no longer work in the near future. If you "
-            "are using a Homebrew or Linuxbrew Python, please see discussion "
-            "at https://github.com/Homebrew/homebrew-core/issues/76621",
+            reason=(
+                "Configuring installation scheme with distutils config files "
+                "is deprecated and will no longer work in the near future. If you "
+                "are using a Homebrew or Linuxbrew Python, please see discussion "
+                "at https://github.com/Homebrew/homebrew-core/issues/76621"
+            ),
             replacement=None,
             gone_in=None,
         )
@@ -333,8 +406,11 @@ def get_scheme(
 
 
 def get_bin_prefix() -> str:
-    old = _distutils.get_bin_prefix()
     new = _sysconfig.get_bin_prefix()
+    if _USE_SYSCONFIG:
+        return new
+
+    old = _distutils.get_bin_prefix()
     if _warn_if_mismatch(pathlib.Path(old), pathlib.Path(new), key="bin_prefix"):
         _log_context()
     return old
@@ -363,8 +439,11 @@ def _looks_like_deb_system_dist_packages(value: str) -> bool:
 
 def get_purelib() -> str:
     """Return the default pure-Python lib location."""
-    old = _distutils.get_purelib()
     new = _sysconfig.get_purelib()
+    if _USE_SYSCONFIG:
+        return new
+
+    old = _distutils.get_purelib()
     if _looks_like_deb_system_dist_packages(old):
         return old
     if _warn_if_mismatch(pathlib.Path(old), pathlib.Path(new), key="purelib"):
@@ -374,35 +453,15 @@ def get_purelib() -> str:
 
 def get_platlib() -> str:
     """Return the default platform-shared lib location."""
-    old = _distutils.get_platlib()
     new = _sysconfig.get_platlib()
+    if _USE_SYSCONFIG:
+        return new
+
+    from . import _distutils
+
+    old = _distutils.get_platlib()
     if _looks_like_deb_system_dist_packages(old):
         return old
     if _warn_if_mismatch(pathlib.Path(old), pathlib.Path(new), key="platlib"):
         _log_context()
     return old
-
-
-def get_prefixed_libs(prefix: str) -> List[str]:
-    """Return the lib locations under ``prefix``."""
-    old_pure, old_plat = _distutils.get_prefixed_libs(prefix)
-    new_pure, new_plat = _sysconfig.get_prefixed_libs(prefix)
-
-    warned = [
-        _warn_if_mismatch(
-            pathlib.Path(old_pure),
-            pathlib.Path(new_pure),
-            key="prefixed-purelib",
-        ),
-        _warn_if_mismatch(
-            pathlib.Path(old_plat),
-            pathlib.Path(new_plat),
-            key="prefixed-platlib",
-        ),
-    ]
-    if any(warned):
-        _log_context(prefix=prefix)
-
-    if old_pure == old_plat:
-        return [old_pure]
-    return [old_pure, old_plat]

venv/Lib/site-packages/pip/_internal/locations/_distutils.py

@@ -3,6 +3,17 @@
 # The following comment should be removed at some point in the future.
 # mypy: strict-optional=False
 
+# If pip's going to use distutils, it should not be using the copy that setuptools
+# might have injected into the environment. This is done by removing the injected
+# shim, if it's injected.
+#
+# See https://github.com/pypa/pip/issues/8761 for the original discussion and
+# rationale for why this is done within pip.
+try:
+    __import__("_distutils_hack").remove_shim()
+except (ImportError, AttributeError):
+    pass
+
 import logging
 import os
 import sys
@@ -10,7 +21,7 @@ from distutils.cmd import Command as DistutilsCommand
 from distutils.command.install import SCHEME_KEYS
 from distutils.command.install import install as distutils_install_command
 from distutils.sysconfig import get_python_lib
-from typing import Dict, List, Optional, Tuple, Union, cast
+from typing import Dict, List, Optional, Union, cast
 
 from pip._internal.models.scheme import Scheme
 from pip._internal.utils.compat import WINDOWS
@@ -24,10 +35,10 @@ logger = logging.getLogger(__name__)
 def distutils_scheme(
     dist_name: str,
     user: bool = False,
-    home: str = None,
-    root: str = None,
+    home: Optional[str] = None,
+    root: Optional[str] = None,
     isolated: bool = False,
-    prefix: str = None,
+    prefix: Optional[str] = None,
     *,
     ignore_config_files: bool = False,
 ) -> Dict[str, str]:
@@ -84,7 +95,7 @@ def distutils_scheme(
         if home:
             prefix = home
         elif user:
-            prefix = i.install_userbase  # type: ignore
+            prefix = i.install_userbase
         else:
             prefix = i.prefix
         scheme["headers"] = os.path.join(
@@ -160,10 +171,3 @@ def get_purelib() -> str:
 
 def get_platlib() -> str:
     return get_python_lib(plat_specific=True)
-
-
-def get_prefixed_libs(prefix: str) -> Tuple[str, str]:
-    return (
-        get_python_lib(plat_specific=False, prefix=prefix),
-        get_python_lib(plat_specific=True, prefix=prefix),
-    )

venv/Lib/site-packages/pip/_internal/locations/_sysconfig.py

@@ -1,4 +1,3 @@
-import distutils.util  # FIXME: For change_root.
 import logging
 import os
 import sys
@@ -9,7 +8,7 @@ from pip._internal.exceptions import InvalidSchemeCombination, UserInstallationI
 from pip._internal.models.scheme import SCHEME_KEYS, Scheme
 from pip._internal.utils.virtualenv import running_under_virtualenv
 
-from .base import get_major_minor_version, is_osx_framework
+from .base import change_root, get_major_minor_version, is_osx_framework
 
 logger = logging.getLogger(__name__)
 
@@ -194,7 +193,7 @@ def get_scheme(
     )
     if root is not None:
         for key in SCHEME_KEYS:
-            value = distutils.util.change_root(root, getattr(scheme, key))
+            value = change_root(root, getattr(scheme, key))
             setattr(scheme, key, value)
     return scheme
 
@@ -212,8 +211,3 @@ def get_purelib() -> str:
 
 def get_platlib() -> str:
     return sysconfig.get_paths()["platlib"]
-
-
-def get_prefixed_libs(prefix: str) -> typing.Tuple[str, str]:
-    paths = sysconfig.get_paths(vars={"base": prefix, "platbase": prefix})
-    return (paths["purelib"], paths["platlib"])

venv/Lib/site-packages/pip/_internal/locations/base.py

@@ -5,6 +5,7 @@ import sys
 import sysconfig
 import typing
 
+from pip._internal.exceptions import InstallationError
 from pip._internal.utils import appdirs
 from pip._internal.utils.virtualenv import running_under_virtualenv
 
@@ -12,7 +13,7 @@ from pip._internal.utils.virtualenv import running_under_virtualenv
 USER_CACHE_DIR = appdirs.user_cache_dir("pip")
 
 # FIXME doesn't account for venv linked to global site-packages
-site_packages: typing.Optional[str] = sysconfig.get_path("purelib")
+site_packages: str = sysconfig.get_path("purelib")
 
 
 def get_major_minor_version() -> str:
@@ -23,6 +24,34 @@ def get_major_minor_version() -> str:
     return "{}.{}".format(*sys.version_info)
 
 
+def change_root(new_root: str, pathname: str) -> str:
+    """Return 'pathname' with 'new_root' prepended.
+
+    If 'pathname' is relative, this is equivalent to os.path.join(new_root, pathname).
+    Otherwise, it requires making 'pathname' relative and then joining the
+    two, which is tricky on DOS/Windows and Mac OS.
+
+    This is borrowed from Python's standard library's distutils module.
+    """
+    if os.name == "posix":
+        if not os.path.isabs(pathname):
+            return os.path.join(new_root, pathname)
+        else:
+            return os.path.join(new_root, pathname[1:])
+
+    elif os.name == "nt":
+        (drive, path) = os.path.splitdrive(pathname)
+        if path[0] == "\\":
+            path = path[1:]
+        return os.path.join(new_root, path)
+
+    else:
+        raise InstallationError(
+            f"Unknown platform: {os.name}\n"
+            "Can not change root path prefix on unknown platform."
+        )
+
+
 def get_src_prefix() -> str:
     if running_under_virtualenv():
         src_prefix = os.path.join(sys.prefix, "src")

venv/Lib/site-packages/pip/_internal/main.py

@@ -1,8 +1,7 @@
 from typing import List, Optional
 
 
-def main(args=None):
-    # type: (Optional[List[str]]) -> int
+def main(args: Optional[List[str]] = None) -> int:
     """This is preserved for old console scripts that may still be referencing
     it.
 

venv/Lib/site-packages/pip/_internal/metadata/__init__.py

@@ -1,16 +1,70 @@
-from typing import List, Optional
+import contextlib
+import functools
+import os
+import sys
+from typing import TYPE_CHECKING, List, Optional, Type, cast
 
-from .base import BaseDistribution, BaseEnvironment
+from pip._internal.utils.misc import strtobool
+
+from .base import BaseDistribution, BaseEnvironment, FilesystemWheel, MemoryWheel, Wheel
+
+if TYPE_CHECKING:
+    from typing import Protocol
+else:
+    Protocol = object
 
 __all__ = [
     "BaseDistribution",
     "BaseEnvironment",
+    "FilesystemWheel",
+    "MemoryWheel",
+    "Wheel",
     "get_default_environment",
     "get_environment",
     "get_wheel_distribution",
+    "select_backend",
 ]
 
 
+def _should_use_importlib_metadata() -> bool:
+    """Whether to use the ``importlib.metadata`` or ``pkg_resources`` backend.
+
+    By default, pip uses ``importlib.metadata`` on Python 3.11+, and
+    ``pkg_resourcess`` otherwise. This can be overridden by a couple of ways:
+
+    * If environment variable ``_PIP_USE_IMPORTLIB_METADATA`` is set, it
+      dictates whether ``importlib.metadata`` is used, regardless of Python
+      version.
+    * On Python 3.11+, Python distributors can patch ``importlib.metadata``
+      to add a global constant ``_PIP_USE_IMPORTLIB_METADATA = False``. This
+      makes pip use ``pkg_resources`` (unless the user set the aforementioned
+      environment variable to *True*).
+    """
+    with contextlib.suppress(KeyError, ValueError):
+        return bool(strtobool(os.environ["_PIP_USE_IMPORTLIB_METADATA"]))
+    if sys.version_info < (3, 11):
+        return False
+    import importlib.metadata
+
+    return bool(getattr(importlib.metadata, "_PIP_USE_IMPORTLIB_METADATA", True))
+
+
+class Backend(Protocol):
+    Distribution: Type[BaseDistribution]
+    Environment: Type[BaseEnvironment]
+
+
+@functools.lru_cache(maxsize=None)
+def select_backend() -> Backend:
+    if _should_use_importlib_metadata():
+        from . import importlib
+
+        return cast(Backend, importlib)
+    from . import pkg_resources
+
+    return cast(Backend, pkg_resources)
+
+
 def get_default_environment() -> BaseEnvironment:
     """Get the default representation for the current environment.
 
@@ -18,9 +72,7 @@ def get_default_environment() -> BaseEnvironment:
     Environment instance should be built from ``sys.path`` and may use caching
     to share instance state accorss calls.
     """
-    from .pkg_resources import Environment
-
-    return Environment.default()
+    return select_backend().Environment.default()
 
 
 def get_environment(paths: Optional[List[str]]) -> BaseEnvironment:
@@ -30,12 +82,19 @@ def get_environment(paths: Optional[List[str]]) -> BaseEnvironment:
     given import paths. The backend must build a fresh instance representing
     the state of installed distributions when this function is called.
     """
-    from .pkg_resources import Environment
-
-    return Environment.from_paths(paths)
+    return select_backend().Environment.from_paths(paths)
 
 
-def get_wheel_distribution(wheel_path: str, canonical_name: str) -> BaseDistribution:
+def get_directory_distribution(directory: str) -> BaseDistribution:
+    """Get the distribution metadata representation in the specified directory.
+
+    This returns a Distribution instance from the chosen backend based on
+    the given on-disk ``.dist-info`` directory.
+    """
+    return select_backend().Distribution.from_directory(directory)
+
+
+def get_wheel_distribution(wheel: Wheel, canonical_name: str) -> BaseDistribution:
     """Get the representation of the specified wheel's distribution metadata.
 
     This returns a Distribution instance from the chosen backend based on
@@ -43,6 +102,26 @@ def get_wheel_distribution(wheel_path: str, canonical_name: str) -> BaseDistribu
 
     :param canonical_name: Normalized project name of the given wheel.
     """
-    from .pkg_resources import Distribution
+    return select_backend().Distribution.from_wheel(wheel, canonical_name)
 
-    return Distribution.from_wheel(wheel_path, canonical_name)
+
+def get_metadata_distribution(
+    metadata_contents: bytes,
+    filename: str,
+    canonical_name: str,
+) -> BaseDistribution:
+    """Get the dist representation of the specified METADATA file contents.
+
+    This returns a Distribution instance from the chosen backend sourced from the data
+    in `metadata_contents`.
+
+    :param metadata_contents: Contents of a METADATA file within a dist, or one served
+                              via PEP 658.
+    :param filename: Filename for the dist this metadata represents.
+    :param canonical_name: Normalized project name of the given dist.
+    """
+    return select_backend().Distribution.from_metadata_file_contents(
+        metadata_contents,
+        filename,
+        canonical_name,
+    )

venv/Lib/site-packages/pip/_internal/metadata/base.py

@@ -1,37 +1,56 @@
+import csv
 import email.message
+import functools
 import json
 import logging
+import pathlib
 import re
+import zipfile
 from typing import (
+    IO,
     TYPE_CHECKING,
+    Any,
     Collection,
     Container,
+    Dict,
     Iterable,
     Iterator,
     List,
+    NamedTuple,
     Optional,
+    Tuple,
     Union,
 )
 
 from pip._vendor.packaging.requirements import Requirement
+from pip._vendor.packaging.specifiers import InvalidSpecifier, SpecifierSet
+from pip._vendor.packaging.utils import NormalizedName
 from pip._vendor.packaging.version import LegacyVersion, Version
 
+from pip._internal.exceptions import NoneMetadataError
+from pip._internal.locations import site_packages, user_site
 from pip._internal.models.direct_url import (
     DIRECT_URL_METADATA_NAME,
     DirectUrl,
     DirectUrlValidationError,
 )
-from pip._internal.utils.misc import stdlib_pkgs  # TODO: Move definition here.
+from pip._internal.utils.compat import stdlib_pkgs  # TODO: Move definition here.
+from pip._internal.utils.egg_link import egg_link_path_from_sys_path
+from pip._internal.utils.misc import is_local, normalize_path
+from pip._internal.utils.packaging import safe_extra
+from pip._internal.utils.urls import url_to_path
+
+from ._json import msg_to_json
 
 if TYPE_CHECKING:
     from typing import Protocol
-
-    from pip._vendor.packaging.utils import NormalizedName
 else:
     Protocol = object
 
 DistributionVersion = Union[LegacyVersion, Version]
 
+InfoPath = Union[str, pathlib.PurePath]
+
 logger = logging.getLogger(__name__)
 
 
@@ -49,7 +68,89 @@ class BaseEntryPoint(Protocol):
         raise NotImplementedError()
 
 
+def _convert_installed_files_path(
+    entry: Tuple[str, ...],
+    info: Tuple[str, ...],
+) -> str:
+    """Convert a legacy installed-files.txt path into modern RECORD path.
+
+    The legacy format stores paths relative to the info directory, while the
+    modern format stores paths relative to the package root, e.g. the
+    site-packages directory.
+
+    :param entry: Path parts of the installed-files.txt entry.
+    :param info: Path parts of the egg-info directory relative to package root.
+    :returns: The converted entry.
+
+    For best compatibility with symlinks, this does not use ``abspath()`` or
+    ``Path.resolve()``, but tries to work with path parts:
+
+    1. While ``entry`` starts with ``..``, remove the equal amounts of parts
+       from ``info``; if ``info`` is empty, start appending ``..`` instead.
+    2. Join the two directly.
+    """
+    while entry and entry[0] == "..":
+        if not info or info[-1] == "..":
+            info += ("..",)
+        else:
+            info = info[:-1]
+        entry = entry[1:]
+    return str(pathlib.Path(*info, *entry))
+
+
+class RequiresEntry(NamedTuple):
+    requirement: str
+    extra: str
+    marker: str
+
+
 class BaseDistribution(Protocol):
+    @classmethod
+    def from_directory(cls, directory: str) -> "BaseDistribution":
+        """Load the distribution from a metadata directory.
+
+        :param directory: Path to a metadata directory, e.g. ``.dist-info``.
+        """
+        raise NotImplementedError()
+
+    @classmethod
+    def from_metadata_file_contents(
+        cls,
+        metadata_contents: bytes,
+        filename: str,
+        project_name: str,
+    ) -> "BaseDistribution":
+        """Load the distribution from the contents of a METADATA file.
+
+        This is used to implement PEP 658 by generating a "shallow" dist object that can
+        be used for resolution without downloading or building the actual dist yet.
+
+        :param metadata_contents: The contents of a METADATA file.
+        :param filename: File name for the dist with this metadata.
+        :param project_name: Name of the project this dist represents.
+        """
+        raise NotImplementedError()
+
+    @classmethod
+    def from_wheel(cls, wheel: "Wheel", name: str) -> "BaseDistribution":
+        """Load the distribution from a given wheel.
+
+        :param wheel: A concrete wheel definition.
+        :param name: File name of the wheel.
+
+        :raises InvalidWheel: Whenever loading of the wheel causes a
+            :py:exc:`zipfile.BadZipFile` exception to be thrown.
+        :raises UnsupportedWheel: If the wheel is a valid zip, but malformed
+            internally.
+        """
+        raise NotImplementedError()
+
+    def __repr__(self) -> str:
+        return f"{self.raw_name} {self.version} ({self.location})"
+
+    def __str__(self) -> str:
+        return f"{self.raw_name} {self.version}"
+
     @property
     def location(self) -> Optional[str]:
         """Where the distribution is loaded from.
@@ -65,8 +166,43 @@ class BaseDistribution(Protocol):
         raise NotImplementedError()
 
     @property
-    def info_directory(self) -> Optional[str]:
-        """Location of the .[egg|dist]-info directory.
+    def editable_project_location(self) -> Optional[str]:
+        """The project location for editable distributions.
+
+        This is the directory where pyproject.toml or setup.py is located.
+        None if the distribution is not installed in editable mode.
+        """
+        # TODO: this property is relatively costly to compute, memoize it ?
+        direct_url = self.direct_url
+        if direct_url:
+            if direct_url.is_local_editable():
+                return url_to_path(direct_url.url)
+        else:
+            # Search for an .egg-link file by walking sys.path, as it was
+            # done before by dist_is_editable().
+            egg_link_path = egg_link_path_from_sys_path(self.raw_name)
+            if egg_link_path:
+                # TODO: get project location from second line of egg_link file
+                #       (https://github.com/pypa/pip/issues/10243)
+                return self.location
+        return None
+
+    @property
+    def installed_location(self) -> Optional[str]:
+        """The distribution's "installed" location.
+
+        This should generally be a ``site-packages`` directory. This is
+        usually ``dist.location``, except for legacy develop-installed packages,
+        where ``dist.location`` is the source code location, and this is where
+        the ``.egg-link`` file is.
+
+        The returned location is normalized (in particular, with symlinks removed).
+        """
+        raise NotImplementedError()
+
+    @property
+    def info_location(self) -> Optional[str]:
+        """Location of the .[egg|dist]-info directory or file.
 
         Similarly to ``location``, a string value is not necessarily a
         filesystem path. ``None`` means the distribution is created in-memory.
@@ -81,13 +217,80 @@ class BaseDistribution(Protocol):
         raise NotImplementedError()
 
     @property
-    def canonical_name(self) -> "NormalizedName":
+    def installed_by_distutils(self) -> bool:
+        """Whether this distribution is installed with legacy distutils format.
+
+        A distribution installed with "raw" distutils not patched by setuptools
+        uses one single file at ``info_location`` to store metadata. We need to
+        treat this specially on uninstallation.
+        """
+        info_location = self.info_location
+        if not info_location:
+            return False
+        return pathlib.Path(info_location).is_file()
+
+    @property
+    def installed_as_egg(self) -> bool:
+        """Whether this distribution is installed as an egg.
+
+        This usually indicates the distribution was installed by (older versions
+        of) easy_install.
+        """
+        location = self.location
+        if not location:
+            return False
+        return location.endswith(".egg")
+
+    @property
+    def installed_with_setuptools_egg_info(self) -> bool:
+        """Whether this distribution is installed with the ``.egg-info`` format.
+
+        This usually indicates the distribution was installed with setuptools
+        with an old pip version or with ``single-version-externally-managed``.
+
+        Note that this ensure the metadata store is a directory. distutils can
+        also installs an ``.egg-info``, but as a file, not a directory. This
+        property is *False* for that case. Also see ``installed_by_distutils``.
+        """
+        info_location = self.info_location
+        if not info_location:
+            return False
+        if not info_location.endswith(".egg-info"):
+            return False
+        return pathlib.Path(info_location).is_dir()
+
+    @property
+    def installed_with_dist_info(self) -> bool:
+        """Whether this distribution is installed with the "modern format".
+
+        This indicates a "modern" installation, e.g. storing metadata in the
+        ``.dist-info`` directory. This applies to installations made by
+        setuptools (but through pip, not directly), or anything using the
+        standardized build backend interface (PEP 517).
+        """
+        info_location = self.info_location
+        if not info_location:
+            return False
+        if not info_location.endswith(".dist-info"):
+            return False
+        return pathlib.Path(info_location).is_dir()
+
+    @property
+    def canonical_name(self) -> NormalizedName:
         raise NotImplementedError()
 
     @property
     def version(self) -> DistributionVersion:
         raise NotImplementedError()
 
+    @property
+    def setuptools_filename(self) -> str:
+        """Convert a project name to its setuptools-compatible filename.
+
+        This is a copy of ``pkg_resources.to_filename()`` for compatibility.
+        """
+        return self.raw_name.replace("-", "_")
+
     @property
     def direct_url(self) -> Optional[DirectUrl]:
         """Obtain a DirectUrl from this distribution.
@@ -116,39 +319,102 @@ class BaseDistribution(Protocol):
 
     @property
     def installer(self) -> str:
-        raise NotImplementedError()
+        try:
+            installer_text = self.read_text("INSTALLER")
+        except (OSError, ValueError, NoneMetadataError):
+            return ""  # Fail silently if the installer file cannot be read.
+        for line in installer_text.splitlines():
+            cleaned_line = line.strip()
+            if cleaned_line:
+                return cleaned_line
+        return ""
+
+    @property
+    def requested(self) -> bool:
+        return self.is_file("REQUESTED")
 
     @property
     def editable(self) -> bool:
-        raise NotImplementedError()
+        return bool(self.editable_project_location)
 
     @property
     def local(self) -> bool:
-        raise NotImplementedError()
+        """If distribution is installed in the current virtual environment.
+
+        Always True if we're not in a virtualenv.
+        """
+        if self.installed_location is None:
+            return False
+        return is_local(self.installed_location)
 
     @property
     def in_usersite(self) -> bool:
-        raise NotImplementedError()
+        if self.installed_location is None or user_site is None:
+            return False
+        return self.installed_location.startswith(normalize_path(user_site))
 
     @property
     def in_site_packages(self) -> bool:
+        if self.installed_location is None or site_packages is None:
+            return False
+        return self.installed_location.startswith(normalize_path(site_packages))
+
+    def is_file(self, path: InfoPath) -> bool:
+        """Check whether an entry in the info directory is a file."""
         raise NotImplementedError()
 
-    def read_text(self, name: str) -> str:
-        """Read a file in the .dist-info (or .egg-info) directory.
+    def iter_distutils_script_names(self) -> Iterator[str]:
+        """Find distutils 'scripts' entries metadata.
 
-        Should raise ``FileNotFoundError`` if ``name`` does not exist in the
-        metadata directory.
+        If 'scripts' is supplied in ``setup.py``, distutils records those in the
+        installed distribution's ``scripts`` directory, a file for each script.
+        """
+        raise NotImplementedError()
+
+    def read_text(self, path: InfoPath) -> str:
+        """Read a file in the info directory.
+
+        :raise FileNotFoundError: If ``path`` does not exist in the directory.
+        :raise NoneMetadataError: If ``path`` exists in the info directory, but
+            cannot be read.
         """
         raise NotImplementedError()
 
     def iter_entry_points(self) -> Iterable[BaseEntryPoint]:
         raise NotImplementedError()
 
+    def _metadata_impl(self) -> email.message.Message:
+        raise NotImplementedError()
+
+    @functools.lru_cache(maxsize=1)
+    def _metadata_cached(self) -> email.message.Message:
+        # When we drop python 3.7 support, move this to the metadata property and use
+        # functools.cached_property instead of lru_cache.
+        metadata = self._metadata_impl()
+        self._add_egg_info_requires(metadata)
+        return metadata
+
     @property
     def metadata(self) -> email.message.Message:
-        """Metadata of distribution parsed from e.g. METADATA or PKG-INFO."""
-        raise NotImplementedError()
+        """Metadata of distribution parsed from e.g. METADATA or PKG-INFO.
+
+        This should return an empty message if the metadata file is unavailable.
+
+        :raises NoneMetadataError: If the metadata file is available, but does
+            not contain valid metadata.
+        """
+        return self._metadata_cached()
+
+    @property
+    def metadata_dict(self) -> Dict[str, Any]:
+        """PEP 566 compliant JSON-serializable representation of METADATA or PKG-INFO.
+
+        This should return an empty dict if the metadata file is unavailable.
+
+        :raises NoneMetadataError: If the metadata file is available, but does
+            not contain valid metadata.
+        """
+        return msg_to_json(self.metadata)
 
     @property
     def metadata_version(self) -> Optional[str]:
@@ -159,12 +425,159 @@ class BaseDistribution(Protocol):
     def raw_name(self) -> str:
         """Value of "Name:" in distribution metadata."""
         # The metadata should NEVER be missing the Name: key, but if it somehow
-        # does not, fall back to the known canonical name.
+        # does, fall back to the known canonical name.
         return self.metadata.get("Name", self.canonical_name)
 
+    @property
+    def requires_python(self) -> SpecifierSet:
+        """Value of "Requires-Python:" in distribution metadata.
+
+        If the key does not exist or contains an invalid value, an empty
+        SpecifierSet should be returned.
+        """
+        value = self.metadata.get("Requires-Python")
+        if value is None:
+            return SpecifierSet()
+        try:
+            # Convert to str to satisfy the type checker; this can be a Header object.
+            spec = SpecifierSet(str(value))
+        except InvalidSpecifier as e:
+            message = "Package %r has an invalid Requires-Python: %s"
+            logger.warning(message, self.raw_name, e)
+            return SpecifierSet()
+        return spec
+
     def iter_dependencies(self, extras: Collection[str] = ()) -> Iterable[Requirement]:
+        """Dependencies of this distribution.
+
+        For modern .dist-info distributions, this is the collection of
+        "Requires-Dist:" entries in distribution metadata.
+        """
         raise NotImplementedError()
 
+    def iter_provided_extras(self) -> Iterable[str]:
+        """Extras provided by this distribution.
+
+        For modern .dist-info distributions, this is the collection of
+        "Provides-Extra:" entries in distribution metadata.
+        """
+        raise NotImplementedError()
+
+    def _iter_declared_entries_from_record(self) -> Optional[Iterator[str]]:
+        try:
+            text = self.read_text("RECORD")
+        except FileNotFoundError:
+            return None
+        # This extra Path-str cast normalizes entries.
+        return (str(pathlib.Path(row[0])) for row in csv.reader(text.splitlines()))
+
+    def _iter_declared_entries_from_legacy(self) -> Optional[Iterator[str]]:
+        try:
+            text = self.read_text("installed-files.txt")
+        except FileNotFoundError:
+            return None
+        paths = (p for p in text.splitlines(keepends=False) if p)
+        root = self.location
+        info = self.info_location
+        if root is None or info is None:
+            return paths
+        try:
+            info_rel = pathlib.Path(info).relative_to(root)
+        except ValueError:  # info is not relative to root.
+            return paths
+        if not info_rel.parts:  # info *is* root.
+            return paths
+        return (
+            _convert_installed_files_path(pathlib.Path(p).parts, info_rel.parts)
+            for p in paths
+        )
+
+    def iter_declared_entries(self) -> Optional[Iterator[str]]:
+        """Iterate through file entries declared in this distribution.
+
+        For modern .dist-info distributions, this is the files listed in the
+        ``RECORD`` metadata file. For legacy setuptools distributions, this
+        comes from ``installed-files.txt``, with entries normalized to be
+        compatible with the format used by ``RECORD``.
+
+        :return: An iterator for listed entries, or None if the distribution
+            contains neither ``RECORD`` nor ``installed-files.txt``.
+        """
+        return (
+            self._iter_declared_entries_from_record()
+            or self._iter_declared_entries_from_legacy()
+        )
+
+    def _iter_requires_txt_entries(self) -> Iterator[RequiresEntry]:
+        """Parse a ``requires.txt`` in an egg-info directory.
+
+        This is an INI-ish format where an egg-info stores dependencies. A
+        section name describes extra other environment markers, while each entry
+        is an arbitrary string (not a key-value pair) representing a dependency
+        as a requirement string (no markers).
+
+        There is a construct in ``importlib.metadata`` called ``Sectioned`` that
+        does mostly the same, but the format is currently considered private.
+        """
+        try:
+            content = self.read_text("requires.txt")
+        except FileNotFoundError:
+            return
+        extra = marker = ""  # Section-less entries don't have markers.
+        for line in content.splitlines():
+            line = line.strip()
+            if not line or line.startswith("#"):  # Comment; ignored.
+                continue
+            if line.startswith("[") and line.endswith("]"):  # A section header.
+                extra, _, marker = line.strip("[]").partition(":")
+                continue
+            yield RequiresEntry(requirement=line, extra=extra, marker=marker)
+
+    def _iter_egg_info_extras(self) -> Iterable[str]:
+        """Get extras from the egg-info directory."""
+        known_extras = {""}
+        for entry in self._iter_requires_txt_entries():
+            if entry.extra in known_extras:
+                continue
+            known_extras.add(entry.extra)
+            yield entry.extra
+
+    def _iter_egg_info_dependencies(self) -> Iterable[str]:
+        """Get distribution dependencies from the egg-info directory.
+
+        To ease parsing, this converts a legacy dependency entry into a PEP 508
+        requirement string. Like ``_iter_requires_txt_entries()``, there is code
+        in ``importlib.metadata`` that does mostly the same, but not do exactly
+        what we need.
+
+        Namely, ``importlib.metadata`` does not normalize the extra name before
+        putting it into the requirement string, which causes marker comparison
+        to fail because the dist-info format do normalize. This is consistent in
+        all currently available PEP 517 backends, although not standardized.
+        """
+        for entry in self._iter_requires_txt_entries():
+            if entry.extra and entry.marker:
+                marker = f'({entry.marker}) and extra == "{safe_extra(entry.extra)}"'
+            elif entry.extra:
+                marker = f'extra == "{safe_extra(entry.extra)}"'
+            elif entry.marker:
+                marker = entry.marker
+            else:
+                marker = ""
+            if marker:
+                yield f"{entry.requirement} ; {marker}"
+            else:
+                yield entry.requirement
+
+    def _add_egg_info_requires(self, metadata: email.message.Message) -> None:
+        """Add egg-info requires.txt information to the metadata."""
+        if not metadata.get_all("Requires-Dist"):
+            for dep in self._iter_egg_info_dependencies():
+                metadata["Requires-Dist"] = dep
+        if not metadata.get_all("Provides-Extra"):
+            for extra in self._iter_egg_info_extras():
+                metadata["Provides-Extra"] = extra
+
 
 class BaseEnvironment:
     """An environment containing distributions to introspect."""
@@ -178,7 +591,11 @@ class BaseEnvironment:
         raise NotImplementedError()
 
     def get_distribution(self, name: str) -> Optional["BaseDistribution"]:
-        """Given a requirement name, return the installed distributions."""
+        """Given a requirement name, return the installed distributions.
+
+        The name may not be normalized. The implementation must canonicalize
+        it for lookup.
+        """
         raise NotImplementedError()
 
     def _iter_distributions(self) -> Iterator["BaseDistribution"]:
@@ -190,8 +607,8 @@ class BaseEnvironment:
         """
         raise NotImplementedError()
 
-    def iter_distributions(self) -> Iterator["BaseDistribution"]:
-        """Iterate through installed distributions."""
+    def iter_all_distributions(self) -> Iterator[BaseDistribution]:
+        """Iterate through all installed distributions without any filtering."""
         for dist in self._iter_distributions():
             # Make sure the distribution actually comes from a valid Python
             # packaging distribution. Pip's AdjacentTempDirectory leaves folders
@@ -221,6 +638,11 @@ class BaseEnvironment:
     ) -> Iterator[BaseDistribution]:
         """Return a list of installed distributions.
 
+        This is based on ``iter_all_distributions()`` with additional filtering
+        options. Note that ``iter_installed_distributions()`` without arguments
+        is *not* equal to ``iter_all_distributions()``, since some of the
+        configurations exclude packages by default.
+
         :param local_only: If True (default), only return installations
         local to the current virtualenv, if in a virtualenv.
         :param skip: An iterable of canonicalized project names to ignore;
@@ -230,7 +652,7 @@ class BaseEnvironment:
         :param user_only: If True, only report installations in the user
         site directory.
         """
-        it = self.iter_distributions()
+        it = self.iter_all_distributions()
         if local_only:
             it = (d for d in it if d.local)
         if not include_editables:
@@ -240,3 +662,27 @@ class BaseEnvironment:
         if user_only:
             it = (d for d in it if d.in_usersite)
         return (d for d in it if d.canonical_name not in skip)
+
+
+class Wheel(Protocol):
+    location: str
+
+    def as_zipfile(self) -> zipfile.ZipFile:
+        raise NotImplementedError()
+
+
+class FilesystemWheel(Wheel):
+    def __init__(self, location: str) -> None:
+        self.location = location
+
+    def as_zipfile(self) -> zipfile.ZipFile:
+        return zipfile.ZipFile(self.location, allowZip64=True)
+
+
+class MemoryWheel(Wheel):
+    def __init__(self, location: str, stream: IO[bytes]) -> None:
+        self.location = location
+        self.stream = stream
+
+    def as_zipfile(self) -> zipfile.ZipFile:
+        return zipfile.ZipFile(self.stream, allowZip64=True)

venv/Lib/site-packages/pip/_internal/metadata/pkg_resources.py

@@ -1,29 +1,28 @@
 import email.message
+import email.parser
 import logging
+import os
 import zipfile
-from typing import (
-    TYPE_CHECKING,
-    Collection,
-    Iterable,
-    Iterator,
-    List,
-    NamedTuple,
-    Optional,
-)
+from typing import Collection, Iterable, Iterator, List, Mapping, NamedTuple, Optional
 
 from pip._vendor import pkg_resources
 from pip._vendor.packaging.requirements import Requirement
-from pip._vendor.packaging.utils import canonicalize_name
+from pip._vendor.packaging.utils import NormalizedName, canonicalize_name
 from pip._vendor.packaging.version import parse as parse_version
 
-from pip._internal.utils import misc  # TODO: Move definition here.
-from pip._internal.utils.packaging import get_installer, get_metadata
-from pip._internal.utils.wheel import pkg_resources_distribution_for_wheel
+from pip._internal.exceptions import InvalidWheel, NoneMetadataError, UnsupportedWheel
+from pip._internal.utils.egg_link import egg_link_path_from_location
+from pip._internal.utils.misc import display_path, normalize_path
+from pip._internal.utils.wheel import parse_wheel, read_wheel_metadata_file
 
-from .base import BaseDistribution, BaseEntryPoint, BaseEnvironment, DistributionVersion
-
-if TYPE_CHECKING:
-    from pip._vendor.packaging.utils import NormalizedName
+from .base import (
+    BaseDistribution,
+    BaseEntryPoint,
+    BaseEnvironment,
+    DistributionVersion,
+    InfoPath,
+    Wheel,
+)
 
 logger = logging.getLogger(__name__)
 
@@ -34,14 +33,101 @@ class EntryPoint(NamedTuple):
     group: str
 
 
+class InMemoryMetadata:
+    """IMetadataProvider that reads metadata files from a dictionary.
+
+    This also maps metadata decoding exceptions to our internal exception type.
+    """
+
+    def __init__(self, metadata: Mapping[str, bytes], wheel_name: str) -> None:
+        self._metadata = metadata
+        self._wheel_name = wheel_name
+
+    def has_metadata(self, name: str) -> bool:
+        return name in self._metadata
+
+    def get_metadata(self, name: str) -> str:
+        try:
+            return self._metadata[name].decode()
+        except UnicodeDecodeError as e:
+            # Augment the default error with the origin of the file.
+            raise UnsupportedWheel(
+                f"Error decoding metadata for {self._wheel_name}: {e} in {name} file"
+            )
+
+    def get_metadata_lines(self, name: str) -> Iterable[str]:
+        return pkg_resources.yield_lines(self.get_metadata(name))
+
+    def metadata_isdir(self, name: str) -> bool:
+        return False
+
+    def metadata_listdir(self, name: str) -> List[str]:
+        return []
+
+    def run_script(self, script_name: str, namespace: str) -> None:
+        pass
+
+
 class Distribution(BaseDistribution):
     def __init__(self, dist: pkg_resources.Distribution) -> None:
         self._dist = dist
 
     @classmethod
-    def from_wheel(cls, path: str, name: str) -> "Distribution":
-        with zipfile.ZipFile(path, allowZip64=True) as zf:
-            dist = pkg_resources_distribution_for_wheel(zf, name, path)
+    def from_directory(cls, directory: str) -> BaseDistribution:
+        dist_dir = directory.rstrip(os.sep)
+
+        # Build a PathMetadata object, from path to metadata. :wink:
+        base_dir, dist_dir_name = os.path.split(dist_dir)
+        metadata = pkg_resources.PathMetadata(base_dir, dist_dir)
+
+        # Determine the correct Distribution object type.
+        if dist_dir.endswith(".egg-info"):
+            dist_cls = pkg_resources.Distribution
+            dist_name = os.path.splitext(dist_dir_name)[0]
+        else:
+            assert dist_dir.endswith(".dist-info")
+            dist_cls = pkg_resources.DistInfoDistribution
+            dist_name = os.path.splitext(dist_dir_name)[0].split("-")[0]
+
+        dist = dist_cls(base_dir, project_name=dist_name, metadata=metadata)
+        return cls(dist)
+
+    @classmethod
+    def from_metadata_file_contents(
+        cls,
+        metadata_contents: bytes,
+        filename: str,
+        project_name: str,
+    ) -> BaseDistribution:
+        metadata_dict = {
+            "METADATA": metadata_contents,
+        }
+        dist = pkg_resources.DistInfoDistribution(
+            location=filename,
+            metadata=InMemoryMetadata(metadata_dict, filename),
+            project_name=project_name,
+        )
+        return cls(dist)
+
+    @classmethod
+    def from_wheel(cls, wheel: Wheel, name: str) -> BaseDistribution:
+        try:
+            with wheel.as_zipfile() as zf:
+                info_dir, _ = parse_wheel(zf, name)
+                metadata_dict = {
+                    path.split("/", 1)[-1]: read_wheel_metadata_file(zf, path)
+                    for path in zf.namelist()
+                    if path.startswith(f"{info_dir}/")
+                }
+        except zipfile.BadZipFile as e:
+            raise InvalidWheel(wheel.location, name) from e
+        except UnsupportedWheel as e:
+            raise UnsupportedWheel(f"{name} has an invalid wheel, {e}")
+        dist = pkg_resources.DistInfoDistribution(
+            location=wheel.location,
+            metadata=InMemoryMetadata(metadata_dict, wheel.location),
+            project_name=name,
+        )
         return cls(dist)
 
     @property
@@ -49,41 +135,52 @@ class Distribution(BaseDistribution):
         return self._dist.location
 
     @property
-    def info_directory(self) -> Optional[str]:
+    def installed_location(self) -> Optional[str]:
+        egg_link = egg_link_path_from_location(self.raw_name)
+        if egg_link:
+            location = egg_link
+        elif self.location:
+            location = self.location
+        else:
+            return None
+        return normalize_path(location)
+
+    @property
+    def info_location(self) -> Optional[str]:
         return self._dist.egg_info
 
     @property
-    def canonical_name(self) -> "NormalizedName":
+    def installed_by_distutils(self) -> bool:
+        # A distutils-installed distribution is provided by FileMetadata. This
+        # provider has a "path" attribute not present anywhere else. Not the
+        # best introspection logic, but pip has been doing this for a long time.
+        try:
+            return bool(self._dist._provider.path)
+        except AttributeError:
+            return False
+
+    @property
+    def canonical_name(self) -> NormalizedName:
         return canonicalize_name(self._dist.project_name)
 
     @property
     def version(self) -> DistributionVersion:
         return parse_version(self._dist.version)
 
-    @property
-    def installer(self) -> str:
-        return get_installer(self._dist)
+    def is_file(self, path: InfoPath) -> bool:
+        return self._dist.has_metadata(str(path))
 
-    @property
-    def editable(self) -> bool:
-        return misc.dist_is_editable(self._dist)
+    def iter_distutils_script_names(self) -> Iterator[str]:
+        yield from self._dist.metadata_listdir("scripts")
 
-    @property
-    def local(self) -> bool:
-        return misc.dist_is_local(self._dist)
-
-    @property
-    def in_usersite(self) -> bool:
-        return misc.dist_in_usersite(self._dist)
-
-    @property
-    def in_site_packages(self) -> bool:
-        return misc.dist_in_site_packages(self._dist)
-
-    def read_text(self, name: str) -> str:
+    def read_text(self, path: InfoPath) -> str:
+        name = str(path)
         if not self._dist.has_metadata(name):
             raise FileNotFoundError(name)
-        return self._dist.get_metadata(name)
+        content = self._dist.get_metadata(name)
+        if content is None:
+            raise NoneMetadataError(self, name)
+        return content
 
     def iter_entry_points(self) -> Iterable[BaseEntryPoint]:
         for group, entries in self._dist.get_entry_map().items():
@@ -91,15 +188,36 @@ class Distribution(BaseDistribution):
                 name, _, value = str(entry_point).partition("=")
                 yield EntryPoint(name=name.strip(), value=value.strip(), group=group)
 
-    @property
-    def metadata(self) -> email.message.Message:
-        return get_metadata(self._dist)
+    def _metadata_impl(self) -> email.message.Message:
+        """
+        :raises NoneMetadataError: if the distribution reports `has_metadata()`
+            True but `get_metadata()` returns None.
+        """
+        if isinstance(self._dist, pkg_resources.DistInfoDistribution):
+            metadata_name = "METADATA"
+        else:
+            metadata_name = "PKG-INFO"
+        try:
+            metadata = self.read_text(metadata_name)
+        except FileNotFoundError:
+            if self.location:
+                displaying_path = display_path(self.location)
+            else:
+                displaying_path = repr(self.location)
+            logger.warning("No metadata found in %s", displaying_path)
+            metadata = ""
+        feed_parser = email.parser.FeedParser()
+        feed_parser.feed(metadata)
+        return feed_parser.close()
 
     def iter_dependencies(self, extras: Collection[str] = ()) -> Iterable[Requirement]:
         if extras:  # pkg_resources raises on invalid extras, so we sanitize.
             extras = frozenset(extras).intersection(self._dist.extras)
         return self._dist.requires(extras)
 
+    def iter_provided_extras(self) -> Iterable[str]:
+        return self._dist.extras
+
 
 class Environment(BaseEnvironment):
     def __init__(self, ws: pkg_resources.WorkingSet) -> None:
@@ -113,6 +231,10 @@ class Environment(BaseEnvironment):
     def from_paths(cls, paths: Optional[List[str]]) -> BaseEnvironment:
         return cls(pkg_resources.WorkingSet(paths))
 
+    def _iter_distributions(self) -> Iterator[BaseDistribution]:
+        for dist in self._ws:
+            yield Distribution(dist)
+
     def _search_distribution(self, name: str) -> Optional[BaseDistribution]:
         """Find a distribution matching the ``name`` in the environment.
 
@@ -120,13 +242,12 @@ class Environment(BaseEnvironment):
         match the behavior of ``pkg_resources.get_distribution()``.
         """
         canonical_name = canonicalize_name(name)
-        for dist in self.iter_distributions():
+        for dist in self.iter_all_distributions():
             if dist.canonical_name == canonical_name:
                 return dist
         return None
 
     def get_distribution(self, name: str) -> Optional[BaseDistribution]:
-
         # Search the distribution by looking through the working set.
         dist = self._search_distribution(name)
         if dist:
@@ -147,7 +268,3 @@ class Environment(BaseEnvironment):
         except pkg_resources.DistributionNotFound:
             return None
         return self._search_distribution(name)
-
-    def _iter_distributions(self) -> Iterator[BaseDistribution]:
-        for dist in self._ws:
-            yield Distribution(dist)

venv/Lib/site-packages/pip/_internal/models/candidate.py

@@ -5,8 +5,7 @@ from pip._internal.utils.models import KeyBasedCompareMixin
 
 
 class InstallationCandidate(KeyBasedCompareMixin):
-    """Represents a potential "candidate" for installation.
-    """
+    """Represents a potential "candidate" for installation."""
 
     __slots__ = ["name", "version", "link"]
 
@@ -17,15 +16,19 @@ class InstallationCandidate(KeyBasedCompareMixin):
 
         super().__init__(
             key=(self.name, self.version, self.link),
-            defining_class=InstallationCandidate
+            defining_class=InstallationCandidate,
         )
 
     def __repr__(self) -> str:
         return "<InstallationCandidate({!r}, {!r}, {!r})>".format(
-            self.name, self.version, self.link,
+            self.name,
+            self.version,
+            self.link,
         )
 
     def __str__(self) -> str:
-        return '{!r} candidate (version {} at {})'.format(
-            self.name, self.version, self.link,
+        return "{!r} candidate (version {} at {})".format(
+            self.name,
+            self.version,
+            self.link,
         )

venv/Lib/site-packages/pip/_internal/models/direct_url.py

@@ -74,14 +74,10 @@ class VcsInfo:
         vcs: str,
         commit_id: str,
         requested_revision: Optional[str] = None,
-        resolved_revision: Optional[str] = None,
-        resolved_revision_type: Optional[str] = None,
     ) -> None:
         self.vcs = vcs
         self.requested_revision = requested_revision
         self.commit_id = commit_id
-        self.resolved_revision = resolved_revision
-        self.resolved_revision_type = resolved_revision_type
 
     @classmethod
     def _from_dict(cls, d: Optional[Dict[str, Any]]) -> Optional["VcsInfo"]:
@@ -91,8 +87,6 @@ class VcsInfo:
             vcs=_get_required(d, str, "vcs"),
             commit_id=_get_required(d, str, "commit_id"),
             requested_revision=_get(d, str, "requested_revision"),
-            resolved_revision=_get(d, str, "resolved_revision"),
-            resolved_revision_type=_get(d, str, "resolved_revision_type"),
         )
 
     def _to_dict(self) -> Dict[str, Any]:
@@ -100,8 +94,6 @@ class VcsInfo:
             vcs=self.vcs,
             requested_revision=self.requested_revision,
             commit_id=self.commit_id,
-            resolved_revision=self.resolved_revision,
-            resolved_revision_type=self.resolved_revision_type,
         )
 
 
@@ -111,17 +103,42 @@ class ArchiveInfo:
     def __init__(
         self,
         hash: Optional[str] = None,
+        hashes: Optional[Dict[str, str]] = None,
     ) -> None:
+        # set hashes before hash, since the hash setter will further populate hashes
+        self.hashes = hashes
         self.hash = hash
 
+    @property
+    def hash(self) -> Optional[str]:
+        return self._hash
+
+    @hash.setter
+    def hash(self, value: Optional[str]) -> None:
+        if value is not None:
+            # Auto-populate the hashes key to upgrade to the new format automatically.
+            # We don't back-populate the legacy hash key from hashes.
+            try:
+                hash_name, hash_value = value.split("=", 1)
+            except ValueError:
+                raise DirectUrlValidationError(
+                    f"invalid archive_info.hash format: {value!r}"
+                )
+            if self.hashes is None:
+                self.hashes = {hash_name: hash_value}
+            elif hash_name not in self.hashes:
+                self.hashes = self.hashes.copy()
+                self.hashes[hash_name] = hash_value
+        self._hash = value
+
     @classmethod
     def _from_dict(cls, d: Optional[Dict[str, Any]]) -> Optional["ArchiveInfo"]:
         if d is None:
             return None
-        return cls(hash=_get(d, str, "hash"))
+        return cls(hash=_get(d, str, "hash"), hashes=_get(d, dict, "hashes"))
 
     def _to_dict(self) -> Dict[str, Any]:
-        return _filter_none(hash=self.hash)
+        return _filter_none(hash=self.hash, hashes=self.hashes)
 
 
 class DirInfo:
@@ -137,9 +154,7 @@ class DirInfo:
     def _from_dict(cls, d: Optional[Dict[str, Any]]) -> Optional["DirInfo"]:
         if d is None:
             return None
-        return cls(
-            editable=_get_required(d, bool, "editable", default=False)
-        )
+        return cls(editable=_get_required(d, bool, "editable", default=False))
 
     def _to_dict(self) -> Dict[str, Any]:
         return _filter_none(editable=self.editable or None)
@@ -149,7 +164,6 @@ InfoType = Union[ArchiveInfo, DirInfo, VcsInfo]
 
 
 class DirectUrl:
-
     def __init__(
         self,
         url: str,
@@ -165,9 +179,9 @@ class DirectUrl:
             return netloc
         user_pass, netloc_no_user_pass = netloc.split("@", 1)
         if (
-            isinstance(self.info, VcsInfo) and
-            self.info.vcs == "git" and
-            user_pass == "git"
+            isinstance(self.info, VcsInfo)
+            and self.info.vcs == "git"
+            and user_pass == "git"
         ):
             return netloc
         if ENV_VAR_RE.match(user_pass):
@@ -218,3 +232,6 @@ class DirectUrl:
 
     def to_json(self) -> str:
         return json.dumps(self.to_dict(), sort_keys=True)
+
+    def is_local_editable(self) -> bool:
+        return isinstance(self.info, DirInfo) and self.info.editable

venv/Lib/site-packages/pip/_internal/models/format_control.py

@@ -6,15 +6,14 @@ from pip._internal.exceptions import CommandError
 
 
 class FormatControl:
-    """Helper for managing formats from which a package can be installed.
-    """
+    """Helper for managing formats from which a package can be installed."""
 
     __slots__ = ["no_binary", "only_binary"]
 
     def __init__(
         self,
         no_binary: Optional[Set[str]] = None,
-        only_binary: Optional[Set[str]] = None
+        only_binary: Optional[Set[str]] = None,
     ) -> None:
         if no_binary is None:
             no_binary = set()
@@ -31,35 +30,30 @@ class FormatControl:
         if self.__slots__ != other.__slots__:
             return False
 
-        return all(
-            getattr(self, k) == getattr(other, k)
-            for k in self.__slots__
-        )
+        return all(getattr(self, k) == getattr(other, k) for k in self.__slots__)
 
     def __repr__(self) -> str:
         return "{}({}, {})".format(
-            self.__class__.__name__,
-            self.no_binary,
-            self.only_binary
+            self.__class__.__name__, self.no_binary, self.only_binary
         )
 
     @staticmethod
     def handle_mutual_excludes(value: str, target: Set[str], other: Set[str]) -> None:
-        if value.startswith('-'):
+        if value.startswith("-"):
             raise CommandError(
                 "--no-binary / --only-binary option requires 1 argument."
             )
-        new = value.split(',')
-        while ':all:' in new:
+        new = value.split(",")
+        while ":all:" in new:
             other.clear()
             target.clear()
-            target.add(':all:')
-            del new[:new.index(':all:') + 1]
+            target.add(":all:")
+            del new[: new.index(":all:") + 1]
             # Without a none, we want to discard everything as :all: covers it
-            if ':none:' not in new:
+            if ":none:" not in new:
                 return
         for name in new:
-            if name == ':none:':
+            if name == ":none:":
                 target.clear()
                 continue
             name = canonicalize_name(name)
@@ -69,16 +63,18 @@ class FormatControl:
     def get_allowed_formats(self, canonical_name: str) -> FrozenSet[str]:
         result = {"binary", "source"}
         if canonical_name in self.only_binary:
-            result.discard('source')
+            result.discard("source")
         elif canonical_name in self.no_binary:
-            result.discard('binary')
-        elif ':all:' in self.only_binary:
-            result.discard('source')
-        elif ':all:' in self.no_binary:
-            result.discard('binary')
+            result.discard("binary")
+        elif ":all:" in self.only_binary:
+            result.discard("source")
+        elif ":all:" in self.no_binary:
+            result.discard("binary")
         return frozenset(result)
 
     def disallow_binaries(self) -> None:
         self.handle_mutual_excludes(
-            ':all:', self.no_binary, self.only_binary,
+            ":all:",
+            self.no_binary,
+            self.only_binary,
         )

venv/Lib/site-packages/pip/_internal/models/index.py

@@ -2,18 +2,16 @@ import urllib.parse
 
 
 class PackageIndex:
-    """Represents a Package Index and provides easier access to endpoints
-    """
+    """Represents a Package Index and provides easier access to endpoints"""
 
-    __slots__ = ['url', 'netloc', 'simple_url', 'pypi_url',
-                 'file_storage_domain']
+    __slots__ = ["url", "netloc", "simple_url", "pypi_url", "file_storage_domain"]
 
     def __init__(self, url: str, file_storage_domain: str) -> None:
         super().__init__()
         self.url = url
         self.netloc = urllib.parse.urlsplit(url).netloc
-        self.simple_url = self._url_for_path('simple')
-        self.pypi_url = self._url_for_path('pypi')
+        self.simple_url = self._url_for_path("simple")
+        self.pypi_url = self._url_for_path("pypi")
 
         # This is part of a temporary hack used to block installs of PyPI
         # packages which depend on external urls only necessary until PyPI can
@@ -24,9 +22,7 @@ class PackageIndex:
         return urllib.parse.urljoin(self.url, path)
 
 
-PyPI = PackageIndex(
-    'https://pypi.org/', file_storage_domain='files.pythonhosted.org'
-)
+PyPI = PackageIndex("https://pypi.org/", file_storage_domain="files.pythonhosted.org")
 TestPyPI = PackageIndex(
-    'https://test.pypi.org/', file_storage_domain='test-files.pythonhosted.org'
+    "https://test.pypi.org/", file_storage_domain="test-files.pythonhosted.org"
 )

venv/Lib/site-packages/pip/_internal/models/link.py

@@ -1,14 +1,28 @@
 import functools
+import itertools
 import logging
 import os
 import posixpath
 import re
 import urllib.parse
-from typing import TYPE_CHECKING, Dict, List, NamedTuple, Optional, Tuple, Union
+from dataclasses import dataclass
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Dict,
+    List,
+    Mapping,
+    NamedTuple,
+    Optional,
+    Tuple,
+    Union,
+)
 
+from pip._internal.utils.deprecation import deprecated
 from pip._internal.utils.filetypes import WHEEL_EXTENSION
 from pip._internal.utils.hashes import Hashes
 from pip._internal.utils.misc import (
+    pairwise,
     redact_auth_from_url,
     split_auth_from_netloc,
     splitext,
@@ -17,38 +31,172 @@ from pip._internal.utils.models import KeyBasedCompareMixin
 from pip._internal.utils.urls import path_to_url, url_to_path
 
 if TYPE_CHECKING:
-    from pip._internal.index.collector import HTMLPage
+    from pip._internal.index.collector import IndexContent
 
 logger = logging.getLogger(__name__)
 
 
-_SUPPORTED_HASHES = ("sha1", "sha224", "sha384", "sha256", "sha512", "md5")
+# Order matters, earlier hashes have a precedence over later hashes for what
+# we will pick to use.
+_SUPPORTED_HASHES = ("sha512", "sha384", "sha256", "sha224", "sha1", "md5")
+
+
+@dataclass(frozen=True)
+class LinkHash:
+    """Links to content may have embedded hash values. This class parses those.
+
+    `name` must be any member of `_SUPPORTED_HASHES`.
+
+    This class can be converted to and from `ArchiveInfo`. While ArchiveInfo intends to
+    be JSON-serializable to conform to PEP 610, this class contains the logic for
+    parsing a hash name and value for correctness, and then checking whether that hash
+    conforms to a schema with `.is_hash_allowed()`."""
+
+    name: str
+    value: str
+
+    _hash_url_fragment_re = re.compile(
+        # NB: we do not validate that the second group (.*) is a valid hex
+        # digest. Instead, we simply keep that string in this class, and then check it
+        # against Hashes when hash-checking is needed. This is easier to debug than
+        # proactively discarding an invalid hex digest, as we handle incorrect hashes
+        # and malformed hashes in the same place.
+        r"[#&]({choices})=([^&]*)".format(
+            choices="|".join(re.escape(hash_name) for hash_name in _SUPPORTED_HASHES)
+        ),
+    )
+
+    def __post_init__(self) -> None:
+        assert self.name in _SUPPORTED_HASHES
+
+    @classmethod
+    def parse_pep658_hash(cls, dist_info_metadata: str) -> Optional["LinkHash"]:
+        """Parse a PEP 658 data-dist-info-metadata hash."""
+        if dist_info_metadata == "true":
+            return None
+        name, sep, value = dist_info_metadata.partition("=")
+        if not sep:
+            return None
+        if name not in _SUPPORTED_HASHES:
+            return None
+        return cls(name=name, value=value)
+
+    @classmethod
+    @functools.lru_cache(maxsize=None)
+    def find_hash_url_fragment(cls, url: str) -> Optional["LinkHash"]:
+        """Search a string for a checksum algorithm name and encoded output value."""
+        match = cls._hash_url_fragment_re.search(url)
+        if match is None:
+            return None
+        name, value = match.groups()
+        return cls(name=name, value=value)
+
+    def as_dict(self) -> Dict[str, str]:
+        return {self.name: self.value}
+
+    def as_hashes(self) -> Hashes:
+        """Return a Hashes instance which checks only for the current hash."""
+        return Hashes({self.name: [self.value]})
+
+    def is_hash_allowed(self, hashes: Optional[Hashes]) -> bool:
+        """
+        Return True if the current hash is allowed by `hashes`.
+        """
+        if hashes is None:
+            return False
+        return hashes.is_hash_allowed(self.name, hex_digest=self.value)
+
+
+def _clean_url_path_part(part: str) -> str:
+    """
+    Clean a "part" of a URL path (i.e. after splitting on "@" characters).
+    """
+    # We unquote prior to quoting to make sure nothing is double quoted.
+    return urllib.parse.quote(urllib.parse.unquote(part))
+
+
+def _clean_file_url_path(part: str) -> str:
+    """
+    Clean the first part of a URL path that corresponds to a local
+    filesystem path (i.e. the first part after splitting on "@" characters).
+    """
+    # We unquote prior to quoting to make sure nothing is double quoted.
+    # Also, on Windows the path part might contain a drive letter which
+    # should not be quoted. On Linux where drive letters do not
+    # exist, the colon should be quoted. We rely on urllib.request
+    # to do the right thing here.
+    return urllib.request.pathname2url(urllib.request.url2pathname(part))
+
+
+# percent-encoded:                   /
+_reserved_chars_re = re.compile("(@|%2F)", re.IGNORECASE)
+
+
+def _clean_url_path(path: str, is_local_path: bool) -> str:
+    """
+    Clean the path portion of a URL.
+    """
+    if is_local_path:
+        clean_func = _clean_file_url_path
+    else:
+        clean_func = _clean_url_path_part
+
+    # Split on the reserved characters prior to cleaning so that
+    # revision strings in VCS URLs are properly preserved.
+    parts = _reserved_chars_re.split(path)
+
+    cleaned_parts = []
+    for to_clean, reserved in pairwise(itertools.chain(parts, [""])):
+        cleaned_parts.append(clean_func(to_clean))
+        # Normalize %xx escapes (e.g. %2f -> %2F)
+        cleaned_parts.append(reserved.upper())
+
+    return "".join(cleaned_parts)
+
+
+def _ensure_quoted_url(url: str) -> str:
+    """
+    Make sure a link is fully quoted.
+    For example, if ' ' occurs in the URL, it will be replaced with "%20",
+    and without double-quoting other characters.
+    """
+    # Split the URL into parts according to the general structure
+    # `scheme://netloc/path;parameters?query#fragment`.
+    result = urllib.parse.urlparse(url)
+    # If the netloc is empty, then the URL refers to a local filesystem path.
+    is_local_path = not result.netloc
+    path = _clean_url_path(result.path, is_local_path=is_local_path)
+    return urllib.parse.urlunparse(result._replace(path=path))
 
 
 class Link(KeyBasedCompareMixin):
-    """Represents a parsed link from a Package Index's simple URL
-    """
+    """Represents a parsed link from a Package Index's simple URL"""
 
     __slots__ = [
         "_parsed_url",
         "_url",
+        "_hashes",
         "comes_from",
         "requires_python",
         "yanked_reason",
+        "dist_info_metadata",
         "cache_link_parsing",
+        "egg_fragment",
     ]
 
     def __init__(
         self,
         url: str,
-        comes_from: Optional[Union[str, "HTMLPage"]] = None,
+        comes_from: Optional[Union[str, "IndexContent"]] = None,
         requires_python: Optional[str] = None,
         yanked_reason: Optional[str] = None,
+        dist_info_metadata: Optional[str] = None,
         cache_link_parsing: bool = True,
+        hashes: Optional[Mapping[str, str]] = None,
     ) -> None:
         """
         :param url: url of the resource pointed to (href of the link)
-        :param comes_from: instance of HTMLPage where the link was found,
+        :param comes_from: instance of IndexContent where the link was found,
             or string.
         :param requires_python: String containing the `Requires-Python`
             metadata field, specified in PEP 345. This may be specified by
@@ -60,15 +208,20 @@ class Link(KeyBasedCompareMixin):
             a simple repository HTML link. If the file has been yanked but
             no reason was provided, this should be the empty string. See
             PEP 592 for more information and the specification.
+        :param dist_info_metadata: the metadata attached to the file, or None if no such
+            metadata is provided. This is the value of the "data-dist-info-metadata"
+            attribute, if present, in a simple repository HTML link. This may be parsed
+            into its own `Link` by `self.metadata_link()`. See PEP 658 for more
+            information and the specification.
         :param cache_link_parsing: A flag that is used elsewhere to determine
-                                   whether resources retrieved from this link
-                                   should be cached. PyPI index urls should
-                                   generally have this set to False, for
-                                   example.
+            whether resources retrieved from this link should be cached. PyPI
+            URLs should generally have this set to False, for example.
+        :param hashes: A mapping of hash names to digests to allow us to
+            determine the validity of a download.
         """
 
         # url can be a UNC windows share
-        if url.startswith('\\\\'):
+        if url.startswith("\\\\"):
             url = path_to_url(url)
 
         self._parsed_url = urllib.parse.urlsplit(url)
@@ -76,27 +229,99 @@ class Link(KeyBasedCompareMixin):
         # trying to set a new value.
         self._url = url
 
+        link_hash = LinkHash.find_hash_url_fragment(url)
+        hashes_from_link = {} if link_hash is None else link_hash.as_dict()
+        if hashes is None:
+            self._hashes = hashes_from_link
+        else:
+            self._hashes = {**hashes, **hashes_from_link}
+
         self.comes_from = comes_from
         self.requires_python = requires_python if requires_python else None
         self.yanked_reason = yanked_reason
+        self.dist_info_metadata = dist_info_metadata
 
         super().__init__(key=url, defining_class=Link)
 
         self.cache_link_parsing = cache_link_parsing
+        self.egg_fragment = self._egg_fragment()
+
+    @classmethod
+    def from_json(
+        cls,
+        file_data: Dict[str, Any],
+        page_url: str,
+    ) -> Optional["Link"]:
+        """
+        Convert an pypi json document from a simple repository page into a Link.
+        """
+        file_url = file_data.get("url")
+        if file_url is None:
+            return None
+
+        url = _ensure_quoted_url(urllib.parse.urljoin(page_url, file_url))
+        pyrequire = file_data.get("requires-python")
+        yanked_reason = file_data.get("yanked")
+        dist_info_metadata = file_data.get("dist-info-metadata")
+        hashes = file_data.get("hashes", {})
+
+        # The Link.yanked_reason expects an empty string instead of a boolean.
+        if yanked_reason and not isinstance(yanked_reason, str):
+            yanked_reason = ""
+        # The Link.yanked_reason expects None instead of False.
+        elif not yanked_reason:
+            yanked_reason = None
+
+        return cls(
+            url,
+            comes_from=page_url,
+            requires_python=pyrequire,
+            yanked_reason=yanked_reason,
+            hashes=hashes,
+            dist_info_metadata=dist_info_metadata,
+        )
+
+    @classmethod
+    def from_element(
+        cls,
+        anchor_attribs: Dict[str, Optional[str]],
+        page_url: str,
+        base_url: str,
+    ) -> Optional["Link"]:
+        """
+        Convert an anchor element's attributes in a simple repository page to a Link.
+        """
+        href = anchor_attribs.get("href")
+        if not href:
+            return None
+
+        url = _ensure_quoted_url(urllib.parse.urljoin(base_url, href))
+        pyrequire = anchor_attribs.get("data-requires-python")
+        yanked_reason = anchor_attribs.get("data-yanked")
+        dist_info_metadata = anchor_attribs.get("data-dist-info-metadata")
+
+        return cls(
+            url,
+            comes_from=page_url,
+            requires_python=pyrequire,
+            yanked_reason=yanked_reason,
+            dist_info_metadata=dist_info_metadata,
+        )
 
     def __str__(self) -> str:
         if self.requires_python:
-            rp = f' (requires-python:{self.requires_python})'
+            rp = f" (requires-python:{self.requires_python})"
         else:
-            rp = ''
+            rp = ""
         if self.comes_from:
-            return '{} (from {}){}'.format(
-                redact_auth_from_url(self._url), self.comes_from, rp)
+            return "{} (from {}){}".format(
+                redact_auth_from_url(self._url), self.comes_from, rp
+            )
         else:
             return redact_auth_from_url(str(self._url))
 
     def __repr__(self) -> str:
-        return f'<Link {self}>'
+        return f"<Link {self}>"
 
     @property
     def url(self) -> str:
@@ -104,7 +329,7 @@ class Link(KeyBasedCompareMixin):
 
     @property
     def filename(self) -> str:
-        path = self.path.rstrip('/')
+        path = self.path.rstrip("/")
         name = posixpath.basename(path)
         if not name:
             # Make sure we don't leak auth information if the netloc
@@ -113,7 +338,7 @@ class Link(KeyBasedCompareMixin):
             return netloc
 
         name = urllib.parse.unquote(name)
-        assert name, f'URL {self._url!r} produced no filename'
+        assert name, f"URL {self._url!r} produced no filename"
         return name
 
     @property
@@ -136,7 +361,7 @@ class Link(KeyBasedCompareMixin):
         return urllib.parse.unquote(self._parsed_url.path)
 
     def splitext(self) -> Tuple[str, str]:
-        return splitext(posixpath.basename(self.path.rstrip('/')))
+        return splitext(posixpath.basename(self.path.rstrip("/")))
 
     @property
     def ext(self) -> str:
@@ -145,18 +370,34 @@ class Link(KeyBasedCompareMixin):
     @property
     def url_without_fragment(self) -> str:
         scheme, netloc, path, query, fragment = self._parsed_url
-        return urllib.parse.urlunsplit((scheme, netloc, path, query, ''))
+        return urllib.parse.urlunsplit((scheme, netloc, path, query, ""))
 
-    _egg_fragment_re = re.compile(r'[#&]egg=([^&]*)')
+    _egg_fragment_re = re.compile(r"[#&]egg=([^&]*)")
 
-    @property
-    def egg_fragment(self) -> Optional[str]:
+    # Per PEP 508.
+    _project_name_re = re.compile(
+        r"^([A-Z0-9]|[A-Z0-9][A-Z0-9._-]*[A-Z0-9])$", re.IGNORECASE
+    )
+
+    def _egg_fragment(self) -> Optional[str]:
         match = self._egg_fragment_re.search(self._url)
         if not match:
             return None
-        return match.group(1)
 
-    _subdirectory_fragment_re = re.compile(r'[#&]subdirectory=([^&]*)')
+        # An egg fragment looks like a PEP 508 project name, along with
+        # an optional extras specifier. Anything else is invalid.
+        project_name = match.group(1)
+        if not self._project_name_re.match(project_name):
+            deprecated(
+                reason=f"{self} contains an egg fragment with a non-PEP 508 name",
+                replacement="to use the req @ url syntax, and remove the egg fragment",
+                gone_in="25.0",
+                issue=11617,
+            )
+
+        return project_name
+
+    _subdirectory_fragment_re = re.compile(r"[#&]subdirectory=([^&]*)")
 
     @property
     def subdirectory_fragment(self) -> Optional[str]:
@@ -165,31 +406,37 @@ class Link(KeyBasedCompareMixin):
             return None
         return match.group(1)
 
-    _hash_re = re.compile(
-        r'({choices})=([a-f0-9]+)'.format(choices="|".join(_SUPPORTED_HASHES))
-    )
+    def metadata_link(self) -> Optional["Link"]:
+        """Implementation of PEP 658 parsing."""
+        # Note that Link.from_element() parsing the "data-dist-info-metadata" attribute
+        # from an HTML anchor tag is typically how the Link.dist_info_metadata attribute
+        # gets set.
+        if self.dist_info_metadata is None:
+            return None
+        metadata_url = f"{self.url_without_fragment}.metadata"
+        metadata_link_hash = LinkHash.parse_pep658_hash(self.dist_info_metadata)
+        if metadata_link_hash is None:
+            return Link(metadata_url)
+        return Link(metadata_url, hashes=metadata_link_hash.as_dict())
+
+    def as_hashes(self) -> Hashes:
+        return Hashes({k: [v] for k, v in self._hashes.items()})
 
     @property
     def hash(self) -> Optional[str]:
-        match = self._hash_re.search(self._url)
-        if match:
-            return match.group(2)
-        return None
+        return next(iter(self._hashes.values()), None)
 
     @property
     def hash_name(self) -> Optional[str]:
-        match = self._hash_re.search(self._url)
-        if match:
-            return match.group(1)
-        return None
+        return next(iter(self._hashes), None)
 
     @property
     def show_url(self) -> str:
-        return posixpath.basename(self._url.split('#', 1)[0].split('?', 1)[0])
+        return posixpath.basename(self._url.split("#", 1)[0].split("?", 1)[0])
 
     @property
     def is_file(self) -> bool:
-        return self.scheme == 'file'
+        return self.scheme == "file"
 
     def is_existing_dir(self) -> bool:
         return self.is_file and os.path.isdir(self.file_path)
@@ -210,19 +457,15 @@ class Link(KeyBasedCompareMixin):
 
     @property
     def has_hash(self) -> bool:
-        return self.hash_name is not None
+        return bool(self._hashes)
 
     def is_hash_allowed(self, hashes: Optional[Hashes]) -> bool:
         """
-        Return True if the link has a hash and it is allowed.
+        Return True if the link has a hash and it is allowed by `hashes`.
         """
-        if hashes is None or not self.has_hash:
+        if hashes is None:
             return False
-        # Assert non-None so mypy knows self.hash_name and self.hash are str.
-        assert self.hash_name is not None
-        assert self.hash is not None
-
-        return hashes.is_hash_allowed(self.hash_name, hex_digest=self.hash)
+        return any(hashes.is_hash_allowed(k, v) for k, v in self._hashes.items())
 
 
 class _CleanResult(NamedTuple):

venv/Lib/site-packages/pip/_internal/models/scheme.py

@@ -6,7 +6,7 @@ https://docs.python.org/3/install/index.html#alternate-installation.
 """
 
 
-SCHEME_KEYS = ['platlib', 'purelib', 'headers', 'scripts', 'data']
+SCHEME_KEYS = ["platlib", "purelib", "headers", "scripts", "data"]
 
 
 class Scheme:

venv/Lib/site-packages/pip/_internal/models/search_scope.py

@@ -20,13 +20,14 @@ class SearchScope:
     Encapsulates the locations that pip is configured to search.
     """
 
-    __slots__ = ["find_links", "index_urls"]
+    __slots__ = ["find_links", "index_urls", "no_index"]
 
     @classmethod
     def create(
         cls,
         find_links: List[str],
         index_urls: List[str],
+        no_index: bool,
     ) -> "SearchScope":
         """
         Create a SearchScope object after normalizing the `find_links`.
@@ -38,7 +39,7 @@ class SearchScope:
         # blindly normalize anything starting with a ~...
         built_find_links: List[str] = []
         for link in find_links:
-            if link.startswith('~'):
+            if link.startswith("~"):
                 new_link = normalize_path(link)
                 if os.path.exists(new_link):
                     link = new_link
@@ -49,33 +50,35 @@ class SearchScope:
         if not has_tls():
             for link in itertools.chain(index_urls, built_find_links):
                 parsed = urllib.parse.urlparse(link)
-                if parsed.scheme == 'https':
+                if parsed.scheme == "https":
                     logger.warning(
-                        'pip is configured with locations that require '
-                        'TLS/SSL, however the ssl module in Python is not '
-                        'available.'
+                        "pip is configured with locations that require "
+                        "TLS/SSL, however the ssl module in Python is not "
+                        "available."
                     )
                     break
 
         return cls(
             find_links=built_find_links,
             index_urls=index_urls,
+            no_index=no_index,
         )
 
     def __init__(
         self,
         find_links: List[str],
         index_urls: List[str],
+        no_index: bool,
     ) -> None:
         self.find_links = find_links
         self.index_urls = index_urls
+        self.no_index = no_index
 
     def get_formatted_locations(self) -> str:
         lines = []
         redacted_index_urls = []
         if self.index_urls and self.index_urls != [PyPI.simple_url]:
             for url in self.index_urls:
-
                 redacted_index_url = redact_auth_from_url(url)
 
                 # Parse the URL
@@ -88,20 +91,23 @@ class SearchScope:
                 # exceptions for malformed URLs
                 if not purl.scheme and not purl.netloc:
                     logger.warning(
-                        'The index url "%s" seems invalid, '
-                        'please provide a scheme.', redacted_index_url)
+                        'The index url "%s" seems invalid, please provide a scheme.',
+                        redacted_index_url,
+                    )
 
                 redacted_index_urls.append(redacted_index_url)
 
-            lines.append('Looking in indexes: {}'.format(
-                ', '.join(redacted_index_urls)))
+            lines.append(
+                "Looking in indexes: {}".format(", ".join(redacted_index_urls))
+            )
 
         if self.find_links:
             lines.append(
-                'Looking in links: {}'.format(', '.join(
-                    redact_auth_from_url(url) for url in self.find_links))
+                "Looking in links: {}".format(
+                    ", ".join(redact_auth_from_url(url) for url in self.find_links)
+                )
             )
-        return '\n'.join(lines)
+        return "\n".join(lines)
 
     def get_index_urls_locations(self, project_name: str) -> List[str]:
         """Returns the locations found via self.index_urls
@@ -112,15 +118,15 @@ class SearchScope:
 
         def mkurl_pypi_url(url: str) -> str:
             loc = posixpath.join(
-                url,
-                urllib.parse.quote(canonicalize_name(project_name)))
+                url, urllib.parse.quote(canonicalize_name(project_name))
+            )
             # For maximum compatibility with easy_install, ensure the path
             # ends in a trailing slash.  Although this isn't in the spec
             # (and PyPI can handle it without the slash) some other index
             # implementations might break if they relied on easy_install's
             # behavior.
-            if not loc.endswith('/'):
-                loc = loc + '/'
+            if not loc.endswith("/"):
+                loc = loc + "/"
             return loc
 
         return [mkurl_pypi_url(url) for url in self.index_urls]

venv/Lib/site-packages/pip/_internal/models/selection_prefs.py

@@ -9,8 +9,13 @@ class SelectionPreferences:
     and installing files.
     """
 
-    __slots__ = ['allow_yanked', 'allow_all_prereleases', 'format_control',
-                 'prefer_binary', 'ignore_requires_python']
+    __slots__ = [
+        "allow_yanked",
+        "allow_all_prereleases",
+        "format_control",
+        "prefer_binary",
+        "ignore_requires_python",
+    ]
 
     # Don't include an allow_yanked default value to make sure each call
     # site considers whether yanked releases are allowed. This also causes

venv/Lib/site-packages/pip/_internal/models/target_python.py

@@ -53,7 +53,7 @@ class TargetPython:
         else:
             py_version_info = normalize_version_info(py_version_info)
 
-        py_version = '.'.join(map(str, py_version_info[:2]))
+        py_version = ".".join(map(str, py_version_info[:2]))
 
         self.abis = abis
         self.implementation = implementation
@@ -70,19 +70,18 @@ class TargetPython:
         """
         display_version = None
         if self._given_py_version_info is not None:
-            display_version = '.'.join(
+            display_version = ".".join(
                 str(part) for part in self._given_py_version_info
             )
 
         key_values = [
-            ('platforms', self.platforms),
-            ('version_info', display_version),
-            ('abis', self.abis),
-            ('implementation', self.implementation),
+            ("platforms", self.platforms),
+            ("version_info", display_version),
+            ("abis", self.abis),
+            ("implementation", self.implementation),
         ]
-        return ' '.join(
-            f'{key}={value!r}' for key, value in key_values
-            if value is not None
+        return " ".join(
+            f"{key}={value!r}" for key, value in key_values if value is not None
         )
 
     def get_tags(self) -> List[Tag]:

venv/Lib/site-packages/pip/_internal/models/wheel.py

@@ -13,10 +13,10 @@ class Wheel:
     """A wheel file"""
 
     wheel_file_re = re.compile(
-        r"""^(?P<namever>(?P<name>.+?)-(?P<ver>.*?))
-        ((-(?P<build>\d[^-]*?))?-(?P<pyver>.+?)-(?P<abi>.+?)-(?P<plat>.+?)
+        r"""^(?P<namever>(?P<name>[^\s-]+?)-(?P<ver>[^\s-]*?))
+        ((-(?P<build>\d[^-]*?))?-(?P<pyver>[^\s-]+?)-(?P<abi>[^\s-]+?)-(?P<plat>[^\s-]+?)
         \.whl|\.dist-info)$""",
-        re.VERBOSE
+        re.VERBOSE,
     )
 
     def __init__(self, filename: str) -> None:
@@ -25,23 +25,20 @@ class Wheel:
         """
         wheel_info = self.wheel_file_re.match(filename)
         if not wheel_info:
-            raise InvalidWheelFilename(
-                f"{filename} is not a valid wheel filename."
-            )
+            raise InvalidWheelFilename(f"{filename} is not a valid wheel filename.")
         self.filename = filename
-        self.name = wheel_info.group('name').replace('_', '-')
+        self.name = wheel_info.group("name").replace("_", "-")
         # we'll assume "_" means "-" due to wheel naming scheme
         # (https://github.com/pypa/pip/issues/1150)
-        self.version = wheel_info.group('ver').replace('_', '-')
-        self.build_tag = wheel_info.group('build')
-        self.pyversions = wheel_info.group('pyver').split('.')
-        self.abis = wheel_info.group('abi').split('.')
-        self.plats = wheel_info.group('plat').split('.')
+        self.version = wheel_info.group("ver").replace("_", "-")
+        self.build_tag = wheel_info.group("build")
+        self.pyversions = wheel_info.group("pyver").split(".")
+        self.abis = wheel_info.group("abi").split(".")
+        self.plats = wheel_info.group("plat").split(".")
 
         # All the tag combinations from this file
         self.file_tags = {
-            Tag(x, y, z) for x in self.pyversions
-            for y in self.abis for z in self.plats
+            Tag(x, y, z) for x in self.pyversions for y in self.abis for z in self.plats
         }
 
     def get_formatted_file_tags(self) -> List[str]:
@@ -61,7 +58,10 @@ class Wheel:
         :raises ValueError: If none of the wheel's file tags match one of
             the supported tags.
         """
-        return min(tags.index(tag) for tag in self.file_tags if tag in tags)
+        try:
+            return next(i for i, t in enumerate(tags) if t in self.file_tags)
+        except StopIteration:
+            raise ValueError()
 
     def find_most_preferred_tag(
         self, tags: List[Tag], tag_to_priority: Dict[Tag, int]

venv/Lib/site-packages/pip/_internal/network/auth.py

@@ -3,9 +3,18 @@
 Contains interface (MultiDomainBasicAuth) and associated glue code for
 providing credentials in the context of network requests.
 """
-
+import logging
+import os
+import shutil
+import subprocess
+import sysconfig
+import typing
 import urllib.parse
-from typing import Any, Dict, List, Optional, Tuple
+from abc import ABC, abstractmethod
+from functools import lru_cache
+from os.path import commonprefix
+from pathlib import Path
+from typing import Any, Dict, List, NamedTuple, Optional, Tuple
 
 from pip._vendor.requests.auth import AuthBase, HTTPBasicAuth
 from pip._vendor.requests.models import Request, Response
@@ -23,59 +32,204 @@ from pip._internal.vcs.versioncontrol import AuthInfo
 
 logger = getLogger(__name__)
 
-Credentials = Tuple[str, str, str]
-
-try:
-    import keyring
-except ImportError:
-    keyring = None
-except Exception as exc:
-    logger.warning(
-        "Keyring is skipped due to an exception: %s",
-        str(exc),
-    )
-    keyring = None
+KEYRING_DISABLED = False
 
 
-def get_keyring_auth(url: Optional[str], username: Optional[str]) -> Optional[AuthInfo]:
-    """Return the tuple auth for a given url from keyring."""
-    global keyring
-    if not url or not keyring:
+class Credentials(NamedTuple):
+    url: str
+    username: str
+    password: str
+
+
+class KeyRingBaseProvider(ABC):
+    """Keyring base provider interface"""
+
+    has_keyring: bool
+
+    @abstractmethod
+    def get_auth_info(self, url: str, username: Optional[str]) -> Optional[AuthInfo]:
+        ...
+
+    @abstractmethod
+    def save_auth_info(self, url: str, username: str, password: str) -> None:
+        ...
+
+
+class KeyRingNullProvider(KeyRingBaseProvider):
+    """Keyring null provider"""
+
+    has_keyring = False
+
+    def get_auth_info(self, url: str, username: Optional[str]) -> Optional[AuthInfo]:
         return None
 
-    try:
-        try:
-            get_credential = keyring.get_credential
-        except AttributeError:
-            pass
-        else:
+    def save_auth_info(self, url: str, username: str, password: str) -> None:
+        return None
+
+
+class KeyRingPythonProvider(KeyRingBaseProvider):
+    """Keyring interface which uses locally imported `keyring`"""
+
+    has_keyring = True
+
+    def __init__(self) -> None:
+        import keyring
+
+        self.keyring = keyring
+
+    def get_auth_info(self, url: str, username: Optional[str]) -> Optional[AuthInfo]:
+        # Support keyring's get_credential interface which supports getting
+        # credentials without a username. This is only available for
+        # keyring>=15.2.0.
+        if hasattr(self.keyring, "get_credential"):
             logger.debug("Getting credentials from keyring for %s", url)
-            cred = get_credential(url, username)
+            cred = self.keyring.get_credential(url, username)
             if cred is not None:
                 return cred.username, cred.password
             return None
 
-        if username:
+        if username is not None:
             logger.debug("Getting password from keyring for %s", url)
-            password = keyring.get_password(url, username)
+            password = self.keyring.get_password(url, username)
             if password:
                 return username, password
+        return None
 
-    except Exception as exc:
-        logger.warning(
-            "Keyring is skipped due to an exception: %s",
-            str(exc),
+    def save_auth_info(self, url: str, username: str, password: str) -> None:
+        self.keyring.set_password(url, username, password)
+
+
+class KeyRingCliProvider(KeyRingBaseProvider):
+    """Provider which uses `keyring` cli
+
+    Instead of calling the keyring package installed alongside pip
+    we call keyring on the command line which will enable pip to
+    use which ever installation of keyring is available first in
+    PATH.
+    """
+
+    has_keyring = True
+
+    def __init__(self, cmd: str) -> None:
+        self.keyring = cmd
+
+    def get_auth_info(self, url: str, username: Optional[str]) -> Optional[AuthInfo]:
+        # This is the default implementation of keyring.get_credential
+        # https://github.com/jaraco/keyring/blob/97689324abcf01bd1793d49063e7ca01e03d7d07/keyring/backend.py#L134-L139
+        if username is not None:
+            password = self._get_password(url, username)
+            if password is not None:
+                return username, password
+        return None
+
+    def save_auth_info(self, url: str, username: str, password: str) -> None:
+        return self._set_password(url, username, password)
+
+    def _get_password(self, service_name: str, username: str) -> Optional[str]:
+        """Mirror the implementation of keyring.get_password using cli"""
+        if self.keyring is None:
+            return None
+
+        cmd = [self.keyring, "get", service_name, username]
+        env = os.environ.copy()
+        env["PYTHONIOENCODING"] = "utf-8"
+        res = subprocess.run(
+            cmd,
+            stdin=subprocess.DEVNULL,
+            stdout=subprocess.PIPE,
+            env=env,
         )
-        keyring = None
-    return None
+        if res.returncode:
+            return None
+        return res.stdout.decode("utf-8").strip(os.linesep)
+
+    def _set_password(self, service_name: str, username: str, password: str) -> None:
+        """Mirror the implementation of keyring.set_password using cli"""
+        if self.keyring is None:
+            return None
+        env = os.environ.copy()
+        env["PYTHONIOENCODING"] = "utf-8"
+        subprocess.run(
+            [self.keyring, "set", service_name, username],
+            input=f"{password}{os.linesep}".encode("utf-8"),
+            env=env,
+            check=True,
+        )
+        return None
+
+
+@lru_cache(maxsize=None)
+def get_keyring_provider(provider: str) -> KeyRingBaseProvider:
+    logger.verbose("Keyring provider requested: %s", provider)
+
+    # keyring has previously failed and been disabled
+    if KEYRING_DISABLED:
+        provider = "disabled"
+    if provider in ["import", "auto"]:
+        try:
+            impl = KeyRingPythonProvider()
+            logger.verbose("Keyring provider set: import")
+            return impl
+        except ImportError:
+            pass
+        except Exception as exc:
+            # In the event of an unexpected exception
+            # we should warn the user
+            msg = "Installed copy of keyring fails with exception %s"
+            if provider == "auto":
+                msg = msg + ", trying to find a keyring executable as a fallback"
+            logger.warning(msg, exc, exc_info=logger.isEnabledFor(logging.DEBUG))
+    if provider in ["subprocess", "auto"]:
+        cli = shutil.which("keyring")
+        if cli and cli.startswith(sysconfig.get_path("scripts")):
+            # all code within this function is stolen from shutil.which implementation
+            @typing.no_type_check
+            def PATH_as_shutil_which_determines_it() -> str:
+                path = os.environ.get("PATH", None)
+                if path is None:
+                    try:
+                        path = os.confstr("CS_PATH")
+                    except (AttributeError, ValueError):
+                        # os.confstr() or CS_PATH is not available
+                        path = os.defpath
+                # bpo-35755: Don't use os.defpath if the PATH environment variable is
+                # set to an empty string
+
+                return path
+
+            scripts = Path(sysconfig.get_path("scripts"))
+
+            paths = []
+            for path in PATH_as_shutil_which_determines_it().split(os.pathsep):
+                p = Path(path)
+                try:
+                    if not p.samefile(scripts):
+                        paths.append(path)
+                except FileNotFoundError:
+                    pass
+
+            path = os.pathsep.join(paths)
+
+            cli = shutil.which("keyring", path=path)
+
+        if cli:
+            logger.verbose("Keyring provider set: subprocess with executable %s", cli)
+            return KeyRingCliProvider(cli)
+
+    logger.verbose("Keyring provider set: disabled")
+    return KeyRingNullProvider()
 
 
 class MultiDomainBasicAuth(AuthBase):
     def __init__(
-        self, prompting: bool = True, index_urls: Optional[List[str]] = None
+        self,
+        prompting: bool = True,
+        index_urls: Optional[List[str]] = None,
+        keyring_provider: str = "auto",
     ) -> None:
         self.prompting = prompting
         self.index_urls = index_urls
+        self.keyring_provider = keyring_provider  # type: ignore[assignment]
         self.passwords: Dict[str, AuthInfo] = {}
         # When the user is prompted to enter credentials and keyring is
         # available, we will offer to save them. If the user accepts,
@@ -84,6 +238,47 @@ class MultiDomainBasicAuth(AuthBase):
         # ``save_credentials`` to save these.
         self._credentials_to_save: Optional[Credentials] = None
 
+    @property
+    def keyring_provider(self) -> KeyRingBaseProvider:
+        return get_keyring_provider(self._keyring_provider)
+
+    @keyring_provider.setter
+    def keyring_provider(self, provider: str) -> None:
+        # The free function get_keyring_provider has been decorated with
+        # functools.cache. If an exception occurs in get_keyring_auth that
+        # cache will be cleared and keyring disabled, take that into account
+        # if you want to remove this indirection.
+        self._keyring_provider = provider
+
+    @property
+    def use_keyring(self) -> bool:
+        # We won't use keyring when --no-input is passed unless
+        # a specific provider is requested because it might require
+        # user interaction
+        return self.prompting or self._keyring_provider not in ["auto", "disabled"]
+
+    def _get_keyring_auth(
+        self,
+        url: Optional[str],
+        username: Optional[str],
+    ) -> Optional[AuthInfo]:
+        """Return the tuple auth for a given url from keyring."""
+        # Do nothing if no url was provided
+        if not url:
+            return None
+
+        try:
+            return self.keyring_provider.get_auth_info(url, username)
+        except Exception as exc:
+            logger.warning(
+                "Keyring is skipped due to an exception: %s",
+                str(exc),
+            )
+            global KEYRING_DISABLED
+            KEYRING_DISABLED = True
+            get_keyring_provider.cache_clear()
+            return None
+
     def _get_index_url(self, url: str) -> Optional[str]:
         """Return the original index URL matching the requested URL.
 
@@ -100,15 +295,42 @@ class MultiDomainBasicAuth(AuthBase):
         if not url or not self.index_urls:
             return None
 
-        for u in self.index_urls:
-            prefix = remove_auth_from_url(u).rstrip("/") + "/"
-            if url.startswith(prefix):
-                return u
-        return None
+        url = remove_auth_from_url(url).rstrip("/") + "/"
+        parsed_url = urllib.parse.urlsplit(url)
+
+        candidates = []
+
+        for index in self.index_urls:
+            index = index.rstrip("/") + "/"
+            parsed_index = urllib.parse.urlsplit(remove_auth_from_url(index))
+            if parsed_url == parsed_index:
+                return index
+
+            if parsed_url.netloc != parsed_index.netloc:
+                continue
+
+            candidate = urllib.parse.urlsplit(index)
+            candidates.append(candidate)
+
+        if not candidates:
+            return None
+
+        candidates.sort(
+            reverse=True,
+            key=lambda candidate: commonprefix(
+                [
+                    parsed_url.path,
+                    candidate.path,
+                ]
+            ).rfind("/"),
+        )
+
+        return urllib.parse.urlunsplit(candidates[0])
 
     def _get_new_credentials(
         self,
         original_url: str,
+        *,
         allow_netrc: bool = True,
         allow_keyring: bool = False,
     ) -> AuthInfo:
@@ -152,8 +374,8 @@ class MultiDomainBasicAuth(AuthBase):
             # The index url is more specific than the netloc, so try it first
             # fmt: off
             kr_auth = (
-                get_keyring_auth(index_url, username) or
-                get_keyring_auth(netloc, username)
+                self._get_keyring_auth(index_url, username) or
+                self._get_keyring_auth(netloc, username)
             )
             # fmt: on
             if kr_auth:
@@ -179,9 +401,16 @@ class MultiDomainBasicAuth(AuthBase):
         # Try to get credentials from original url
         username, password = self._get_new_credentials(original_url)
 
-        # If credentials not found, use any stored credentials for this netloc
-        if username is None and password is None:
-            username, password = self.passwords.get(netloc, (None, None))
+        # If credentials not found, use any stored credentials for this netloc.
+        # Do this if either the username or the password is missing.
+        # This accounts for the situation in which the user has specified
+        # the username in the index url, but the password comes from keyring.
+        if (username is None or password is None) and netloc in self.passwords:
+            un, pw = self.passwords[netloc]
+            # It is possible that the cached credentials are for a different username,
+            # in which case the cache should be ignored.
+            if username is None or username == un:
+                username, password = un, pw
 
         if username is not None or password is not None:
             # Convert the username and password if they're None, so that
@@ -223,18 +452,23 @@ class MultiDomainBasicAuth(AuthBase):
     def _prompt_for_password(
         self, netloc: str
     ) -> Tuple[Optional[str], Optional[str], bool]:
-        username = ask_input(f"User for {netloc}: ")
+        username = ask_input(f"User for {netloc}: ") if self.prompting else None
         if not username:
             return None, None, False
-        auth = get_keyring_auth(netloc, username)
-        if auth and auth[0] is not None and auth[1] is not None:
-            return auth[0], auth[1], False
+        if self.use_keyring:
+            auth = self._get_keyring_auth(netloc, username)
+            if auth and auth[0] is not None and auth[1] is not None:
+                return auth[0], auth[1], False
         password = ask_password("Password: ")
         return username, password, True
 
     # Factored out to allow for easy patching in tests
     def _should_save_password_to_keyring(self) -> bool:
-        if not keyring:
+        if (
+            not self.prompting
+            or not self.use_keyring
+            or not self.keyring_provider.has_keyring
+        ):
             return False
         return ask("Save credentials to keyring [y/N]: ", ["y", "n"]) == "y"
 
@@ -244,19 +478,22 @@ class MultiDomainBasicAuth(AuthBase):
         if resp.status_code != 401:
             return resp
 
+        username, password = None, None
+
+        # Query the keyring for credentials:
+        if self.use_keyring:
+            username, password = self._get_new_credentials(
+                resp.url,
+                allow_netrc=False,
+                allow_keyring=True,
+            )
+
         # We are not able to prompt the user so simply return the response
-        if not self.prompting:
+        if not self.prompting and not username and not password:
             return resp
 
         parsed = urllib.parse.urlparse(resp.url)
 
-        # Query the keyring for credentials:
-        username, password = self._get_new_credentials(
-            resp.url,
-            allow_netrc=False,
-            allow_keyring=True,
-        )
-
         # Prompt the user for a new username and password
         save = False
         if not username and not password:
@@ -269,7 +506,11 @@ class MultiDomainBasicAuth(AuthBase):
 
             # Prompt to save the password to keyring
             if save and self._should_save_password_to_keyring():
-                self._credentials_to_save = (parsed.netloc, username, password)
+                self._credentials_to_save = Credentials(
+                    url=parsed.netloc,
+                    username=username,
+                    password=password,
+                )
 
         # Consume content and release the original connection to allow our new
         #   request to reuse the same one.
@@ -302,15 +543,17 @@ class MultiDomainBasicAuth(AuthBase):
 
     def save_credentials(self, resp: Response, **kwargs: Any) -> None:
         """Response callback to save credentials on success."""
-        assert keyring is not None, "should never reach here without keyring"
-        if not keyring:
-            return
+        assert (
+            self.keyring_provider.has_keyring
+        ), "should never reach here without keyring"
 
         creds = self._credentials_to_save
         self._credentials_to_save = None
         if creds and resp.status_code < 400:
             try:
                 logger.info("Saving credentials to keyring")
-                keyring.set_password(*creds)
+                self.keyring_provider.save_auth_info(
+                    creds.url, creds.username, creds.password
+                )
             except Exception:
                 logger.exception("Failed to save credentials")

venv/Lib/site-packages/pip/_internal/network/cache.py

@@ -3,7 +3,7 @@
 
 import os
 from contextlib import contextmanager
-from typing import Iterator, Optional
+from typing import Generator, Optional
 
 from pip._vendor.cachecontrol.cache import BaseCache
 from pip._vendor.cachecontrol.caches import FileCache
@@ -18,7 +18,7 @@ def is_from_cache(response: Response) -> bool:
 
 
 @contextmanager
-def suppressed_cache_errors() -> Iterator[None]:
+def suppressed_cache_errors() -> Generator[None, None, None]:
     """If we can't access the cache then we can just skip caching and process
     requests as if caching wasn't enabled.
     """
@@ -53,7 +53,7 @@ class SafeFileCache(BaseCache):
             with open(path, "rb") as f:
                 return f.read()
 
-    def set(self, key: str, value: bytes) -> None:
+    def set(self, key: str, value: bytes, expires: Optional[int] = None) -> None:
         path = self._get_cache_path(key)
         with suppressed_cache_errors():
             ensure_dir(os.path.dirname(path))

venv/Lib/site-packages/pip/_internal/network/download.py

@@ -1,6 +1,6 @@
 """Download files with progress indicators.
 """
-import cgi
+import email.message
 import logging
 import mimetypes
 import os
@@ -8,7 +8,7 @@ from typing import Iterable, Optional, Tuple
 
 from pip._vendor.requests.models import CONTENT_CHUNK_SIZE, Response
 
-from pip._internal.cli.progress_bars import DownloadProgressProvider
+from pip._internal.cli.progress_bars import get_download_progress_renderer
 from pip._internal.exceptions import NetworkConnectionError
 from pip._internal.models.index import PyPI
 from pip._internal.models.link import Link
@@ -65,7 +65,8 @@ def _prepare_download(
     if not show_progress:
         return chunks
 
-    return DownloadProgressProvider(progress_bar, max=total_length)(chunks)
+    renderer = get_download_progress_renderer(bar_type=progress_bar, size=total_length)
+    return renderer(chunks)
 
 
 def sanitize_content_filename(filename: str) -> str:
@@ -80,12 +81,13 @@ def parse_content_disposition(content_disposition: str, default_filename: str) -
     Parse the "filename" value from a Content-Disposition header, and
     return the default filename if the result is empty.
     """
-    _type, params = cgi.parse_header(content_disposition)
-    filename = params.get("filename")
+    m = email.message.Message()
+    m["content-type"] = content_disposition
+    filename = m.get_param("filename")
     if filename:
         # We need to sanitize the filename to prevent directory traversal
         # in case the filename contains ".." path parts.
-        filename = sanitize_content_filename(filename)
+        filename = sanitize_content_filename(str(filename))
     return filename or default_filename
 
 

venv/Lib/site-packages/pip/_internal/network/lazy_wheel.py

@@ -5,36 +5,36 @@ __all__ = ["HTTPRangeRequestUnsupported", "dist_from_wheel_url"]
 from bisect import bisect_left, bisect_right
 from contextlib import contextmanager
 from tempfile import NamedTemporaryFile
-from typing import Any, Dict, Iterator, List, Optional, Tuple
-from zipfile import BadZipfile, ZipFile
+from typing import Any, Dict, Generator, List, Optional, Tuple
+from zipfile import BadZipFile, ZipFile
 
-from pip._vendor.pkg_resources import Distribution
+from pip._vendor.packaging.utils import canonicalize_name
 from pip._vendor.requests.models import CONTENT_CHUNK_SIZE, Response
 
+from pip._internal.metadata import BaseDistribution, MemoryWheel, get_wheel_distribution
 from pip._internal.network.session import PipSession
 from pip._internal.network.utils import HEADERS, raise_for_status, response_chunks
-from pip._internal.utils.wheel import pkg_resources_distribution_for_wheel
 
 
 class HTTPRangeRequestUnsupported(Exception):
     pass
 
 
-def dist_from_wheel_url(name: str, url: str, session: PipSession) -> Distribution:
-    """Return a pkg_resources.Distribution from the given wheel URL.
+def dist_from_wheel_url(name: str, url: str, session: PipSession) -> BaseDistribution:
+    """Return a distribution object from the given wheel URL.
 
-    This uses HTTP range requests to only fetch the potion of the wheel
+    This uses HTTP range requests to only fetch the portion of the wheel
     containing metadata, just enough for the object to be constructed.
     If such requests are not supported, HTTPRangeRequestUnsupported
     is raised.
     """
-    with LazyZipOverHTTP(url, session) as wheel:
+    with LazyZipOverHTTP(url, session) as zf:
         # For read-only ZIP files, ZipFile only needs methods read,
         # seek, seekable and tell, not the whole IO protocol.
-        zip_file = ZipFile(wheel)  # type: ignore
+        wheel = MemoryWheel(zf.name, zf)  # type: ignore
         # After context manager exit, wheel.name
         # is an invalid file by intention.
-        return pkg_resources_distribution_for_wheel(zip_file, name, wheel.name)
+        return get_wheel_distribution(wheel, canonicalize_name(name))
 
 
 class LazyZipOverHTTP:
@@ -135,11 +135,11 @@ class LazyZipOverHTTP:
         self._file.__enter__()
         return self
 
-    def __exit__(self, *exc: Any) -> Optional[bool]:
-        return self._file.__exit__(*exc)
+    def __exit__(self, *exc: Any) -> None:
+        self._file.__exit__(*exc)
 
     @contextmanager
-    def _stay(self) -> Iterator[None]:
+    def _stay(self) -> Generator[None, None, None]:
         """Return a context manager keeping the position.
 
         At the end of the block, seek back to original position.
@@ -160,7 +160,7 @@ class LazyZipOverHTTP:
                     # For read-only ZIP files, ZipFile only needs
                     # methods read, seek, seekable and tell.
                     ZipFile(self)  # type: ignore
-                except BadZipfile:
+                except BadZipFile:
                     pass
                 else:
                     break
@@ -177,8 +177,8 @@ class LazyZipOverHTTP:
 
     def _merge(
         self, start: int, end: int, left: int, right: int
-    ) -> Iterator[Tuple[int, int]]:
-        """Return an iterator of intervals to be fetched.
+    ) -> Generator[Tuple[int, int], None, None]:
+        """Return a generator of intervals to be fetched.
 
         Args:
             start (int): Start of needed interval

venv/Lib/site-packages/pip/_internal/network/session.py

@@ -2,17 +2,8 @@
 network request configuration and behavior.
 """
 
-# When mypy runs on Windows the call to distro.linux_distribution() is skipped
-# resulting in the failure:
-#
-#     error: unused 'type: ignore' comment
-#
-# If the upstream module adds typing, this comment should be removed. See
-# https://github.com/nir0s/distro/pull/269
-#
-# mypy: warn-unused-ignores=False
-
 import email.utils
+import io
 import ipaddress
 import json
 import logging
@@ -24,11 +15,23 @@ import subprocess
 import sys
 import urllib.parse
 import warnings
-from typing import Any, Dict, Iterator, List, Mapping, Optional, Sequence, Tuple, Union
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Dict,
+    Generator,
+    List,
+    Mapping,
+    Optional,
+    Sequence,
+    Tuple,
+    Union,
+)
 
 from pip._vendor import requests, urllib3
-from pip._vendor.cachecontrol import CacheControlAdapter
-from pip._vendor.requests.adapters import BaseAdapter, HTTPAdapter
+from pip._vendor.cachecontrol import CacheControlAdapter as _BaseCacheControlAdapter
+from pip._vendor.requests.adapters import DEFAULT_POOLBLOCK, BaseAdapter
+from pip._vendor.requests.adapters import HTTPAdapter as _BaseHTTPAdapter
 from pip._vendor.requests.models import PreparedRequest, Response
 from pip._vendor.requests.structures import CaseInsensitiveDict
 from pip._vendor.urllib3.connectionpool import ConnectionPool
@@ -46,6 +49,12 @@ from pip._internal.utils.glibc import libc_ver
 from pip._internal.utils.misc import build_url_from_netloc, parse_netloc
 from pip._internal.utils.urls import url_to_path
 
+if TYPE_CHECKING:
+    from ssl import SSLContext
+
+    from pip._vendor.urllib3.poolmanager import PoolManager
+
+
 logger = logging.getLogger(__name__)
 
 SecureOrigin = Tuple[str, str, Optional[Union[int, str]]]
@@ -128,9 +137,8 @@ def user_agent() -> str:
     if sys.platform.startswith("linux"):
         from pip._vendor import distro
 
-        # https://github.com/nir0s/distro/pull/269
-        linux_distribution = distro.linux_distribution()  # type: ignore
-        distro_infos = dict(
+        linux_distribution = distro.name(), distro.version(), distro.codename()
+        distro_infos: Dict[str, Any] = dict(
             filter(
                 lambda x: x[1],
                 zip(["name", "version", "id"], linux_distribution),
@@ -218,8 +226,11 @@ class LocalFSAdapter(BaseAdapter):
         try:
             stats = os.stat(pathname)
         except OSError as exc:
+            # format the exception raised as a io.BytesIO object,
+            # to return a better error message:
             resp.status_code = 404
-            resp.raw = exc
+            resp.reason = type(exc).__name__
+            resp.raw = io.BytesIO(f"{resp.reason}: {exc}".encode("utf8"))
         else:
             modified = email.utils.formatdate(stats.st_mtime, usegmt=True)
             content_type = mimetypes.guess_type(pathname)[0] or "text/plain"
@@ -240,6 +251,48 @@ class LocalFSAdapter(BaseAdapter):
         pass
 
 
+class _SSLContextAdapterMixin:
+    """Mixin to add the ``ssl_context`` constructor argument to HTTP adapters.
+
+    The additional argument is forwarded directly to the pool manager. This allows us
+    to dynamically decide what SSL store to use at runtime, which is used to implement
+    the optional ``truststore`` backend.
+    """
+
+    def __init__(
+        self,
+        *,
+        ssl_context: Optional["SSLContext"] = None,
+        **kwargs: Any,
+    ) -> None:
+        self._ssl_context = ssl_context
+        super().__init__(**kwargs)
+
+    def init_poolmanager(
+        self,
+        connections: int,
+        maxsize: int,
+        block: bool = DEFAULT_POOLBLOCK,
+        **pool_kwargs: Any,
+    ) -> "PoolManager":
+        if self._ssl_context is not None:
+            pool_kwargs.setdefault("ssl_context", self._ssl_context)
+        return super().init_poolmanager(  # type: ignore[misc]
+            connections=connections,
+            maxsize=maxsize,
+            block=block,
+            **pool_kwargs,
+        )
+
+
+class HTTPAdapter(_SSLContextAdapterMixin, _BaseHTTPAdapter):
+    pass
+
+
+class CacheControlAdapter(_SSLContextAdapterMixin, _BaseCacheControlAdapter):
+    pass
+
+
 class InsecureHTTPAdapter(HTTPAdapter):
     def cert_verify(
         self,
@@ -263,7 +316,6 @@ class InsecureCacheControlAdapter(CacheControlAdapter):
 
 
 class PipSession(requests.Session):
-
     timeout: Optional[int] = None
 
     def __init__(
@@ -273,6 +325,7 @@ class PipSession(requests.Session):
         cache: Optional[str] = None,
         trusted_hosts: Sequence[str] = (),
         index_urls: Optional[List[str]] = None,
+        ssl_context: Optional["SSLContext"] = None,
         **kwargs: Any,
     ) -> None:
         """
@@ -325,13 +378,14 @@ class PipSession(requests.Session):
             secure_adapter = CacheControlAdapter(
                 cache=SafeFileCache(cache),
                 max_retries=retries,
+                ssl_context=ssl_context,
             )
             self._trusted_host_adapter = InsecureCacheControlAdapter(
                 cache=SafeFileCache(cache),
                 max_retries=retries,
             )
         else:
-            secure_adapter = HTTPAdapter(max_retries=retries)
+            secure_adapter = HTTPAdapter(max_retries=retries, ssl_context=ssl_context)
             self._trusted_host_adapter = insecure_adapter
 
         self.mount("https://", secure_adapter)
@@ -369,12 +423,19 @@ class PipSession(requests.Session):
         if host_port not in self.pip_trusted_origins:
             self.pip_trusted_origins.append(host_port)
 
+        self.mount(
+            build_url_from_netloc(host, scheme="http") + "/", self._trusted_host_adapter
+        )
         self.mount(build_url_from_netloc(host) + "/", self._trusted_host_adapter)
         if not host_port[1]:
+            self.mount(
+                build_url_from_netloc(host, scheme="http") + ":",
+                self._trusted_host_adapter,
+            )
             # Mount wildcard ports for the same host.
             self.mount(build_url_from_netloc(host) + ":", self._trusted_host_adapter)
 
-    def iter_secure_origins(self) -> Iterator[SecureOrigin]:
+    def iter_secure_origins(self) -> Generator[SecureOrigin, None, None]:
         yield from SECURE_ORIGINS
         for host, port in self.pip_trusted_origins:
             yield ("*", host, "*" if port is None else port)
@@ -403,7 +464,7 @@ class PipSession(requests.Session):
                 continue
 
             try:
-                addr = ipaddress.ip_address(origin_host)
+                addr = ipaddress.ip_address(origin_host or "")
                 network = ipaddress.ip_network(secure_host)
             except ValueError:
                 # We don't have both a valid address or a valid network, so
@@ -449,6 +510,8 @@ class PipSession(requests.Session):
     def request(self, method: str, url: str, *args: Any, **kwargs: Any) -> Response:
         # Allow setting a default timeout on a session
         kwargs.setdefault("timeout", self.timeout)
+        # Allow setting a default proxies on a session
+        kwargs.setdefault("proxies", self.proxies)
 
         # Dispatch the actual request
         return super().request(method, url, *args, **kwargs)

venv/Lib/site-packages/pip/_internal/network/utils.py

@@ -1,4 +1,4 @@
-from typing import Dict, Iterator
+from typing import Dict, Generator
 
 from pip._vendor.requests.models import CONTENT_CHUNK_SIZE, Response
 
@@ -56,7 +56,7 @@ def raise_for_status(resp: Response) -> None:
 
 def response_chunks(
     response: Response, chunk_size: int = CONTENT_CHUNK_SIZE
-) -> Iterator[bytes]:
+) -> Generator[bytes, None, None]:
     """Given a requests Response, provide the data chunks."""
     try:
         # Special case for urllib3.

venv/Lib/site-packages/pip/_internal/operations/build/metadata.py

@@ -3,33 +3,37 @@
 
 import os
 
-from pip._vendor.pep517.wrappers import Pep517HookCaller
+from pip._vendor.pyproject_hooks import BuildBackendHookCaller
 
 from pip._internal.build_env import BuildEnvironment
+from pip._internal.exceptions import (
+    InstallationSubprocessError,
+    MetadataGenerationFailed,
+)
 from pip._internal.utils.subprocess import runner_with_spinner_message
 from pip._internal.utils.temp_dir import TempDirectory
 
 
-def generate_metadata(build_env, backend):
-    # type: (BuildEnvironment, Pep517HookCaller) -> str
+def generate_metadata(
+    build_env: BuildEnvironment, backend: BuildBackendHookCaller, details: str
+) -> str:
     """Generate metadata using mechanisms described in PEP 517.
 
     Returns the generated metadata directory.
     """
-    metadata_tmpdir = TempDirectory(
-        kind="modern-metadata", globally_managed=True
-    )
+    metadata_tmpdir = TempDirectory(kind="modern-metadata", globally_managed=True)
 
     metadata_dir = metadata_tmpdir.path
 
     with build_env:
-        # Note that Pep517HookCaller implements a fallback for
+        # Note that BuildBackendHookCaller implements a fallback for
         # prepare_metadata_for_build_wheel, so we don't have to
         # consider the possibility that this hook doesn't exist.
-        runner = runner_with_spinner_message("Preparing wheel metadata")
+        runner = runner_with_spinner_message("Preparing metadata (pyproject.toml)")
         with backend.subprocess_runner(runner):
-            distinfo_dir = backend.prepare_metadata_for_build_wheel(
-                metadata_dir
-            )
+            try:
+                distinfo_dir = backend.prepare_metadata_for_build_wheel(metadata_dir)
+            except InstallationSubprocessError as error:
+                raise MetadataGenerationFailed(package_details=details) from error
 
     return os.path.join(metadata_dir, distinfo_dir)

venv/Lib/site-packages/pip/_internal/operations/build/metadata_legacy.py

@@ -5,7 +5,12 @@ import logging
 import os
 
 from pip._internal.build_env import BuildEnvironment
-from pip._internal.exceptions import InstallationError
+from pip._internal.cli.spinners import open_spinner
+from pip._internal.exceptions import (
+    InstallationError,
+    InstallationSubprocessError,
+    MetadataGenerationFailed,
+)
 from pip._internal.utils.setuptools_build import make_setuptools_egg_info_args
 from pip._internal.utils.subprocess import call_subprocess
 from pip._internal.utils.temp_dir import TempDirectory
@@ -13,49 +18,39 @@ from pip._internal.utils.temp_dir import TempDirectory
 logger = logging.getLogger(__name__)
 
 
-def _find_egg_info(directory):
-    # type: (str) -> str
-    """Find an .egg-info subdirectory in `directory`.
-    """
-    filenames = [
-        f for f in os.listdir(directory) if f.endswith(".egg-info")
-    ]
+def _find_egg_info(directory: str) -> str:
+    """Find an .egg-info subdirectory in `directory`."""
+    filenames = [f for f in os.listdir(directory) if f.endswith(".egg-info")]
 
     if not filenames:
-        raise InstallationError(
-            f"No .egg-info directory found in {directory}"
-        )
+        raise InstallationError(f"No .egg-info directory found in {directory}")
 
     if len(filenames) > 1:
         raise InstallationError(
-            "More than one .egg-info directory found in {}".format(
-                directory
-            )
+            "More than one .egg-info directory found in {}".format(directory)
         )
 
     return os.path.join(directory, filenames[0])
 
 
 def generate_metadata(
-    build_env,  # type: BuildEnvironment
-    setup_py_path,  # type: str
-    source_dir,  # type: str
-    isolated,  # type: bool
-    details,  # type: str
-):
-    # type: (...) -> str
+    build_env: BuildEnvironment,
+    setup_py_path: str,
+    source_dir: str,
+    isolated: bool,
+    details: str,
+) -> str:
     """Generate metadata using setup.py-based defacto mechanisms.
 
     Returns the generated metadata directory.
     """
     logger.debug(
-        'Running setup.py (path:%s) egg_info for package %s',
-        setup_py_path, details,
+        "Running setup.py (path:%s) egg_info for package %s",
+        setup_py_path,
+        details,
     )
 
-    egg_info_dir = TempDirectory(
-        kind="pip-egg-info", globally_managed=True
-    ).path
+    egg_info_dir = TempDirectory(kind="pip-egg-info", globally_managed=True).path
 
     args = make_setuptools_egg_info_args(
         setup_py_path,
@@ -64,11 +59,16 @@ def generate_metadata(
     )
 
     with build_env:
-        call_subprocess(
-            args,
-            cwd=source_dir,
-            command_desc='python setup.py egg_info',
-        )
+        with open_spinner("Preparing metadata (setup.py)") as spinner:
+            try:
+                call_subprocess(
+                    args,
+                    cwd=source_dir,
+                    command_desc="python setup.py egg_info",
+                    spinner=spinner,
+                )
+            except InstallationSubprocessError as error:
+                raise MetadataGenerationFailed(package_details=details) from error
 
     # Return the .egg-info directory.
     return _find_egg_info(egg_info_dir)

venv/Lib/site-packages/pip/_internal/operations/build/wheel.py

@@ -2,7 +2,7 @@ import logging
 import os
 from typing import Optional
 
-from pip._vendor.pep517.wrappers import Pep517HookCaller
+from pip._vendor.pyproject_hooks import BuildBackendHookCaller
 
 from pip._internal.utils.subprocess import runner_with_spinner_message
 
@@ -10,22 +10,21 @@ logger = logging.getLogger(__name__)
 
 
 def build_wheel_pep517(
-    name,  # type: str
-    backend,  # type: Pep517HookCaller
-    metadata_directory,  # type: str
-    tempd,  # type: str
-):
-    # type: (...) -> Optional[str]
+    name: str,
+    backend: BuildBackendHookCaller,
+    metadata_directory: str,
+    tempd: str,
+) -> Optional[str]:
     """Build one InstallRequirement using the PEP 517 build process.
 
     Returns path to wheel if successfully built. Otherwise, returns None.
     """
     assert metadata_directory is not None
     try:
-        logger.debug('Destination directory: %s', tempd)
+        logger.debug("Destination directory: %s", tempd)
 
         runner = runner_with_spinner_message(
-            f'Building wheel for {name} (PEP 517)'
+            f"Building wheel for {name} (pyproject.toml)"
         )
         with backend.subprocess_runner(runner):
             wheel_name = backend.build_wheel(
@@ -33,6 +32,6 @@ def build_wheel_pep517(
                 metadata_directory=metadata_directory,
             )
     except Exception:
-        logger.error('Failed building wheel for %s', name)
+        logger.error("Failed building wheel for %s", name)
         return None
     return os.path.join(tempd, wheel_name)

venv/Lib/site-packages/pip/_internal/operations/build/wheel_legacy.py

@@ -4,59 +4,51 @@ from typing import List, Optional
 
 from pip._internal.cli.spinners import open_spinner
 from pip._internal.utils.setuptools_build import make_setuptools_bdist_wheel_args
-from pip._internal.utils.subprocess import (
-    LOG_DIVIDER,
-    call_subprocess,
-    format_command_args,
-)
+from pip._internal.utils.subprocess import call_subprocess, format_command_args
 
 logger = logging.getLogger(__name__)
 
 
 def format_command_result(
-    command_args,  # type: List[str]
-    command_output,  # type: str
-):
-    # type: (...) -> str
+    command_args: List[str],
+    command_output: str,
+) -> str:
     """Format command information for logging."""
     command_desc = format_command_args(command_args)
-    text = f'Command arguments: {command_desc}\n'
+    text = f"Command arguments: {command_desc}\n"
 
     if not command_output:
-        text += 'Command output: None'
+        text += "Command output: None"
     elif logger.getEffectiveLevel() > logging.DEBUG:
-        text += 'Command output: [use --verbose to show]'
+        text += "Command output: [use --verbose to show]"
     else:
-        if not command_output.endswith('\n'):
-            command_output += '\n'
-        text += f'Command output:\n{command_output}{LOG_DIVIDER}'
+        if not command_output.endswith("\n"):
+            command_output += "\n"
+        text += f"Command output:\n{command_output}"
 
     return text
 
 
 def get_legacy_build_wheel_path(
-    names,  # type: List[str]
-    temp_dir,  # type: str
-    name,  # type: str
-    command_args,  # type: List[str]
-    command_output,  # type: str
-):
-    # type: (...) -> Optional[str]
+    names: List[str],
+    temp_dir: str,
+    name: str,
+    command_args: List[str],
+    command_output: str,
+) -> Optional[str]:
     """Return the path to the wheel in the temporary build directory."""
     # Sort for determinism.
     names = sorted(names)
     if not names:
-        msg = (
-            'Legacy build of wheel for {!r} created no files.\n'
-        ).format(name)
+        msg = ("Legacy build of wheel for {!r} created no files.\n").format(name)
         msg += format_command_result(command_args, command_output)
         logger.warning(msg)
         return None
 
     if len(names) > 1:
         msg = (
-            'Legacy build of wheel for {!r} created more than one file.\n'
-            'Filenames (choosing first): {}\n'
+            "Legacy build of wheel for {!r} created more than one file.\n"
+            "Filenames (choosing first): {}\n"
         ).format(name, names)
         msg += format_command_result(command_args, command_output)
         logger.warning(msg)
@@ -65,14 +57,13 @@ def get_legacy_build_wheel_path(
 
 
 def build_wheel_legacy(
-    name,  # type: str
-    setup_py_path,  # type: str
-    source_dir,  # type: str
-    global_options,  # type: List[str]
-    build_options,  # type: List[str]
-    tempd,  # type: str
-):
-    # type: (...) -> Optional[str]
+    name: str,
+    setup_py_path: str,
+    source_dir: str,
+    global_options: List[str],
+    build_options: List[str],
+    tempd: str,
+) -> Optional[str]:
     """Build one unpacked package using the "legacy" build process.
 
     Returns path to wheel if successfully built. Otherwise, returns None.
@@ -84,19 +75,20 @@ def build_wheel_legacy(
         destination_dir=tempd,
     )
 
-    spin_message = f'Building wheel for {name} (setup.py)'
+    spin_message = f"Building wheel for {name} (setup.py)"
     with open_spinner(spin_message) as spinner:
-        logger.debug('Destination directory: %s', tempd)
+        logger.debug("Destination directory: %s", tempd)
 
         try:
             output = call_subprocess(
                 wheel_args,
+                command_desc="python setup.py bdist_wheel",
                 cwd=source_dir,
                 spinner=spinner,
             )
         except Exception:
             spinner.finish("error")
-            logger.error('Failed building wheel for %s', name)
+            logger.error("Failed building wheel for %s", name)
             return None
 
         names = os.listdir(tempd)

venv/Lib/site-packages/pip/_internal/operations/check.py

@@ -2,19 +2,16 @@
 """
 
 import logging
-from typing import TYPE_CHECKING, Callable, Dict, List, NamedTuple, Optional, Set, Tuple
+from typing import Callable, Dict, List, NamedTuple, Optional, Set, Tuple
 
 from pip._vendor.packaging.requirements import Requirement
-from pip._vendor.packaging.utils import canonicalize_name
+from pip._vendor.packaging.utils import NormalizedName, canonicalize_name
 
 from pip._internal.distributions import make_distribution_for_install_requirement
 from pip._internal.metadata import get_default_environment
 from pip._internal.metadata.base import DistributionVersion
 from pip._internal.req.req_install import InstallRequirement
 
-if TYPE_CHECKING:
-    from pip._vendor.packaging.utils import NormalizedName
-
 logger = logging.getLogger(__name__)
 
 
@@ -24,12 +21,12 @@ class PackageDetails(NamedTuple):
 
 
 # Shorthands
-PackageSet = Dict['NormalizedName', PackageDetails]
-Missing = Tuple['NormalizedName', Requirement]
-Conflicting = Tuple['NormalizedName', DistributionVersion, Requirement]
+PackageSet = Dict[NormalizedName, PackageDetails]
+Missing = Tuple[NormalizedName, Requirement]
+Conflicting = Tuple[NormalizedName, DistributionVersion, Requirement]
 
-MissingDict = Dict['NormalizedName', List[Missing]]
-ConflictingDict = Dict['NormalizedName', List[Conflicting]]
+MissingDict = Dict[NormalizedName, List[Missing]]
+ConflictingDict = Dict[NormalizedName, List[Conflicting]]
 CheckResult = Tuple[MissingDict, ConflictingDict]
 ConflictDetails = Tuple[PackageSet, CheckResult]
 
@@ -51,8 +48,9 @@ def create_package_set_from_installed() -> Tuple[PackageSet, bool]:
     return package_set, problems
 
 
-def check_package_set(package_set, should_ignore=None):
-    # type: (PackageSet, Optional[Callable[[str], bool]]) -> CheckResult
+def check_package_set(
+    package_set: PackageSet, should_ignore: Optional[Callable[[str], bool]] = None
+) -> CheckResult:
     """Check if a package set is consistent
 
     If should_ignore is passed, it should be a callable that takes a
@@ -64,8 +62,8 @@ def check_package_set(package_set, should_ignore=None):
 
     for package_name, package_detail in package_set.items():
         # Info about dependencies of package_name
-        missing_deps = set()  # type: Set[Missing]
-        conflicting_deps = set()  # type: Set[Conflicting]
+        missing_deps: Set[Missing] = set()
+        conflicting_deps: Set[Conflicting] = set()
 
         if should_ignore and should_ignore(package_name):
             continue
@@ -77,7 +75,7 @@ def check_package_set(package_set, should_ignore=None):
             if name not in package_set:
                 missed = True
                 if req.marker is not None:
-                    missed = req.marker.evaluate()
+                    missed = req.marker.evaluate({"extra": ""})
                 if missed:
                     missing_deps.add((name, req))
                 continue
@@ -95,8 +93,7 @@ def check_package_set(package_set, should_ignore=None):
     return missing, conflicting
 
 
-def check_install_conflicts(to_install):
-    # type: (List[InstallRequirement]) -> ConflictDetails
+def check_install_conflicts(to_install: List[InstallRequirement]) -> ConflictDetails:
     """For checking if the dependency graph would be consistent after \
     installing given requirements
     """
@@ -112,33 +109,32 @@ def check_install_conflicts(to_install):
         package_set,
         check_package_set(
             package_set, should_ignore=lambda name: name not in whitelist
-        )
+        ),
     )
 
 
-def _simulate_installation_of(to_install, package_set):
-    # type: (List[InstallRequirement], PackageSet) -> Set[NormalizedName]
-    """Computes the version of packages after installing to_install.
-    """
+def _simulate_installation_of(
+    to_install: List[InstallRequirement], package_set: PackageSet
+) -> Set[NormalizedName]:
+    """Computes the version of packages after installing to_install."""
     # Keep track of packages that were installed
     installed = set()
 
     # Modify it as installing requirement_set would (assuming no errors)
     for inst_req in to_install:
         abstract_dist = make_distribution_for_install_requirement(inst_req)
-        dist = abstract_dist.get_pkg_resources_distribution()
-
-        assert dist is not None
-        name = canonicalize_name(dist.project_name)
-        package_set[name] = PackageDetails(dist.parsed_version, dist.requires())
+        dist = abstract_dist.get_metadata_distribution()
+        name = dist.canonical_name
+        package_set[name] = PackageDetails(dist.version, list(dist.iter_dependencies()))
 
         installed.add(name)
 
     return installed
 
 
-def _create_whitelist(would_be_installed, package_set):
-    # type: (Set[NormalizedName], PackageSet) -> Set[NormalizedName]
+def _create_whitelist(
+    would_be_installed: Set[NormalizedName], package_set: PackageSet
+) -> Set[NormalizedName]:
     packages_affected = set(would_be_installed)
 
     for package_name in package_set:

venv/Lib/site-packages/pip/_internal/operations/freeze.py

@@ -1,19 +1,8 @@
 import collections
 import logging
 import os
-from typing import (
-    Container,
-    Dict,
-    Iterable,
-    Iterator,
-    List,
-    NamedTuple,
-    Optional,
-    Set,
-    Union,
-)
+from typing import Container, Dict, Generator, Iterable, List, NamedTuple, Optional, Set
 
-from pip._vendor.packaging.requirements import Requirement
 from pip._vendor.packaging.utils import canonicalize_name
 from pip._vendor.packaging.version import Version
 
@@ -30,22 +19,20 @@ logger = logging.getLogger(__name__)
 
 
 class _EditableInfo(NamedTuple):
-    requirement: Optional[str]
-    editable: bool
+    requirement: str
     comments: List[str]
 
 
 def freeze(
-    requirement=None,  # type: Optional[List[str]]
-    local_only=False,  # type: bool
-    user_only=False,  # type: bool
-    paths=None,  # type: Optional[List[str]]
-    isolated=False,  # type: bool
-    exclude_editable=False,  # type: bool
-    skip=()  # type: Container[str]
-):
-    # type: (...) -> Iterator[str]
-    installations = {}  # type: Dict[str, FrozenRequirement]
+    requirement: Optional[List[str]] = None,
+    local_only: bool = False,
+    user_only: bool = False,
+    paths: Optional[List[str]] = None,
+    isolated: bool = False,
+    exclude_editable: bool = False,
+    skip: Container[str] = (),
+) -> Generator[str, None, None]:
+    installations: Dict[str, FrozenRequirement] = {}
 
     dists = get_environment(paths).iter_installed_distributions(
         local_only=local_only,
@@ -63,42 +50,50 @@ def freeze(
         # should only be emitted once, even if the same option is in multiple
         # requirements files, so we need to keep track of what has been emitted
         # so that we don't emit it again if it's seen again
-        emitted_options = set()  # type: Set[str]
+        emitted_options: Set[str] = set()
         # keep track of which files a requirement is in so that we can
         # give an accurate warning if a requirement appears multiple times.
-        req_files = collections.defaultdict(list)  # type: Dict[str, List[str]]
+        req_files: Dict[str, List[str]] = collections.defaultdict(list)
         for req_file_path in requirement:
             with open(req_file_path) as req_file:
                 for line in req_file:
-                    if (not line.strip() or
-                            line.strip().startswith('#') or
-                            line.startswith((
-                                '-r', '--requirement',
-                                '-f', '--find-links',
-                                '-i', '--index-url',
-                                '--pre',
-                                '--trusted-host',
-                                '--process-dependency-links',
-                                '--extra-index-url',
-                                '--use-feature'))):
+                    if (
+                        not line.strip()
+                        or line.strip().startswith("#")
+                        or line.startswith(
+                            (
+                                "-r",
+                                "--requirement",
+                                "-f",
+                                "--find-links",
+                                "-i",
+                                "--index-url",
+                                "--pre",
+                                "--trusted-host",
+                                "--process-dependency-links",
+                                "--extra-index-url",
+                                "--use-feature",
+                            )
+                        )
+                    ):
                         line = line.rstrip()
                         if line not in emitted_options:
                             emitted_options.add(line)
                             yield line
                         continue
 
-                    if line.startswith('-e') or line.startswith('--editable'):
-                        if line.startswith('-e'):
+                    if line.startswith("-e") or line.startswith("--editable"):
+                        if line.startswith("-e"):
                             line = line[2:].strip()
                         else:
-                            line = line[len('--editable'):].strip().lstrip('=')
+                            line = line[len("--editable") :].strip().lstrip("=")
                         line_req = install_req_from_editable(
                             line,
                             isolated=isolated,
                         )
                     else:
                         line_req = install_req_from_line(
-                            COMMENT_RE.sub('', line).strip(),
+                            COMMENT_RE.sub("", line).strip(),
                             isolated=isolated,
                         )
 
@@ -106,15 +101,15 @@ def freeze(
                         logger.info(
                             "Skipping line in requirement file [%s] because "
                             "it's not clear what it would install: %s",
-                            req_file_path, line.strip(),
+                            req_file_path,
+                            line.strip(),
                         )
                         logger.info(
                             "  (add #egg=PackageName to the URL to avoid"
                             " this warning)"
                         )
                     else:
-                        line_req_canonical_name = canonicalize_name(
-                            line_req.name)
+                        line_req_canonical_name = canonicalize_name(line_req.name)
                         if line_req_canonical_name not in installations:
                             # either it's not installed, or it is installed
                             # but has been processed already
@@ -123,14 +118,13 @@ def freeze(
                                     "Requirement file [%s] contains %s, but "
                                     "package %r is not installed",
                                     req_file_path,
-                                    COMMENT_RE.sub('', line).strip(),
-                                    line_req.name
+                                    COMMENT_RE.sub("", line).strip(),
+                                    line_req.name,
                                 )
                             else:
                                 req_files[line_req.name].append(req_file_path)
                         else:
-                            yield str(installations[
-                                line_req_canonical_name]).rstrip()
+                            yield str(installations[line_req_canonical_name]).rstrip()
                             del installations[line_req_canonical_name]
                             req_files[line_req.name].append(req_file_path)
 
@@ -138,42 +132,33 @@ def freeze(
         # single requirements file or in different requirements files).
         for name, files in req_files.items():
             if len(files) > 1:
-                logger.warning("Requirement %s included multiple times [%s]",
-                               name, ', '.join(sorted(set(files))))
+                logger.warning(
+                    "Requirement %s included multiple times [%s]",
+                    name,
+                    ", ".join(sorted(set(files))),
+                )
 
-        yield(
-            '## The following requirements were added by '
-            'pip freeze:'
-        )
-    for installation in sorted(
-            installations.values(), key=lambda x: x.name.lower()):
+        yield ("## The following requirements were added by pip freeze:")
+    for installation in sorted(installations.values(), key=lambda x: x.name.lower()):
         if installation.canonical_name not in skip:
             yield str(installation).rstrip()
 
 
 def _format_as_name_version(dist: BaseDistribution) -> str:
-    if isinstance(dist.version, Version):
-        return f"{dist.raw_name}=={dist.version}"
-    return f"{dist.raw_name}==={dist.version}"
+    dist_version = dist.version
+    if isinstance(dist_version, Version):
+        return f"{dist.raw_name}=={dist_version}"
+    return f"{dist.raw_name}==={dist_version}"
 
 
 def _get_editable_info(dist: BaseDistribution) -> _EditableInfo:
     """
-    Compute and return values (req, editable, comments) for use in
+    Compute and return values (req, comments) for use in
     FrozenRequirement.from_dist().
     """
-    if not dist.editable:
-        return _EditableInfo(requirement=None, editable=False, comments=[])
-    if dist.location is None:
-        display = _format_as_name_version(dist)
-        logger.warning("Editable requirement not found on disk: %s", display)
-        return _EditableInfo(
-            requirement=None,
-            editable=True,
-            comments=[f"# Editable install not found ({display})"],
-        )
-
-    location = os.path.normcase(os.path.abspath(dist.location))
+    editable_project_location = dist.editable_project_location
+    assert editable_project_location
+    location = os.path.normcase(os.path.abspath(editable_project_location))
 
     from pip._internal.vcs import RemoteNotFoundError, RemoteNotValidError, vcs
 
@@ -182,13 +167,13 @@ def _get_editable_info(dist: BaseDistribution) -> _EditableInfo:
     if vcs_backend is None:
         display = _format_as_name_version(dist)
         logger.debug(
-            'No VCS found for editable requirement "%s" in: %r', display,
+            'No VCS found for editable requirement "%s" in: %r',
+            display,
             location,
         )
         return _EditableInfo(
             requirement=location,
-            editable=True,
-            comments=[f'# Editable install with no version control ({display})'],
+            comments=[f"# Editable install with no version control ({display})"],
         )
 
     vcs_name = type(vcs_backend).__name__
@@ -199,50 +184,47 @@ def _get_editable_info(dist: BaseDistribution) -> _EditableInfo:
         display = _format_as_name_version(dist)
         return _EditableInfo(
             requirement=location,
-            editable=True,
-            comments=[f'# Editable {vcs_name} install with no remote ({display})'],
+            comments=[f"# Editable {vcs_name} install with no remote ({display})"],
         )
     except RemoteNotValidError as ex:
         display = _format_as_name_version(dist)
         return _EditableInfo(
             requirement=location,
-            editable=True,
             comments=[
                 f"# Editable {vcs_name} install ({display}) with either a deleted "
                 f"local remote or invalid URI:",
                 f"# '{ex.url}'",
             ],
         )
-
     except BadCommand:
         logger.warning(
-            'cannot determine version of editable source in %s '
-            '(%s command not found in path)',
+            "cannot determine version of editable source in %s "
+            "(%s command not found in path)",
             location,
             vcs_backend.name,
         )
-        return _EditableInfo(requirement=None, editable=True, comments=[])
-
+        return _EditableInfo(requirement=location, comments=[])
     except InstallationError as exc:
-        logger.warning(
-            "Error when trying to get requirement for VCS system %s, "
-            "falling back to uneditable format", exc
-        )
+        logger.warning("Error when trying to get requirement for VCS system %s", exc)
     else:
-        return _EditableInfo(requirement=req, editable=True, comments=[])
+        return _EditableInfo(requirement=req, comments=[])
 
-    logger.warning('Could not determine repository location of %s', location)
+    logger.warning("Could not determine repository location of %s", location)
 
     return _EditableInfo(
-        requirement=None,
-        editable=False,
-        comments=['## !! Could not determine repository location'],
+        requirement=location,
+        comments=["## !! Could not determine repository location"],
     )
 
 
 class FrozenRequirement:
-    def __init__(self, name, req, editable, comments=()):
-        # type: (str, Union[str, Requirement], bool, Iterable[str]) -> None
+    def __init__(
+        self,
+        name: str,
+        req: str,
+        editable: bool,
+        comments: Iterable[str] = (),
+    ) -> None:
         self.name = name
         self.canonical_name = canonicalize_name(name)
         self.req = req
@@ -251,27 +233,23 @@ class FrozenRequirement:
 
     @classmethod
     def from_dist(cls, dist: BaseDistribution) -> "FrozenRequirement":
-        # TODO `get_requirement_info` is taking care of editable requirements.
-        # TODO This should be refactored when we will add detection of
-        #      editable that provide .dist-info metadata.
-        req, editable, comments = _get_editable_info(dist)
-        if req is None and not editable:
-            # if PEP 610 metadata is present, attempt to use it
+        editable = dist.editable
+        if editable:
+            req, comments = _get_editable_info(dist)
+        else:
+            comments = []
             direct_url = dist.direct_url
             if direct_url:
-                req = direct_url_as_pep440_direct_reference(
-                    direct_url, dist.raw_name
-                )
-                comments = []
-        if req is None:
-            # name==version requirement
-            req = _format_as_name_version(dist)
+                # if PEP 610 metadata is present, use it
+                req = direct_url_as_pep440_direct_reference(direct_url, dist.raw_name)
+            else:
+                # name==version requirement
+                req = _format_as_name_version(dist)
 
         return cls(dist.raw_name, req, editable, comments=comments)
 
-    def __str__(self):
-        # type: () -> str
+    def __str__(self) -> str:
         req = self.req
         if self.editable:
-            req = f'-e {req}'
-        return '\n'.join(list(self.comments) + [str(req)]) + '\n'
+            req = f"-e {req}"
+        return "\n".join(list(self.comments) + [str(req)]) + "\n"

venv/Lib/site-packages/pip/_internal/operations/install/editable_legacy.py

@@ -1,7 +1,7 @@
 """Legacy editable installation process, i.e. `setup.py develop`.
 """
 import logging
-from typing import List, Optional, Sequence
+from typing import Optional, Sequence
 
 from pip._internal.build_env import BuildEnvironment
 from pip._internal.utils.logging import indent_log
@@ -12,27 +12,25 @@ logger = logging.getLogger(__name__)
 
 
 def install_editable(
-    install_options,  # type: List[str]
-    global_options,  # type: Sequence[str]
-    prefix,  # type: Optional[str]
-    home,  # type: Optional[str]
-    use_user_site,  # type: bool
-    name,  # type: str
-    setup_py_path,  # type: str
-    isolated,  # type: bool
-    build_env,  # type: BuildEnvironment
-    unpacked_source_directory,  # type: str
-):
-    # type: (...) -> None
+    *,
+    global_options: Sequence[str],
+    prefix: Optional[str],
+    home: Optional[str],
+    use_user_site: bool,
+    name: str,
+    setup_py_path: str,
+    isolated: bool,
+    build_env: BuildEnvironment,
+    unpacked_source_directory: str,
+) -> None:
     """Install a package in editable mode. Most arguments are pass-through
     to setuptools.
     """
-    logger.info('Running setup.py develop for %s', name)
+    logger.info("Running setup.py develop for %s", name)
 
     args = make_setuptools_develop_args(
         setup_py_path,
         global_options=global_options,
-        install_options=install_options,
         no_user_config=isolated,
         prefix=prefix,
         home=home,
@@ -43,5 +41,6 @@ def install_editable(
         with build_env:
             call_subprocess(
                 args,
+                command_desc="python setup.py develop",
                 cwd=unpacked_source_directory,
             )

venv/Lib/site-packages/pip/_internal/operations/install/legacy.py

@@ -1,132 +0,0 @@
-"""Legacy installation process, i.e. `setup.py install`.
-"""
-
-import logging
-import os
-import sys
-from distutils.util import change_root
-from typing import List, Optional, Sequence
-
-from pip._internal.build_env import BuildEnvironment
-from pip._internal.exceptions import InstallationError
-from pip._internal.models.scheme import Scheme
-from pip._internal.utils.logging import indent_log
-from pip._internal.utils.misc import ensure_dir
-from pip._internal.utils.setuptools_build import make_setuptools_install_args
-from pip._internal.utils.subprocess import runner_with_spinner_message
-from pip._internal.utils.temp_dir import TempDirectory
-
-logger = logging.getLogger(__name__)
-
-
-class LegacyInstallFailure(Exception):
-    def __init__(self):
-        # type: () -> None
-        self.parent = sys.exc_info()
-
-
-def write_installed_files_from_setuptools_record(
-    record_lines: List[str],
-    root: Optional[str],
-    req_description: str,
-) -> None:
-    def prepend_root(path):
-        # type: (str) -> str
-        if root is None or not os.path.isabs(path):
-            return path
-        else:
-            return change_root(root, path)
-
-    for line in record_lines:
-        directory = os.path.dirname(line)
-        if directory.endswith('.egg-info'):
-            egg_info_dir = prepend_root(directory)
-            break
-    else:
-        message = (
-            "{} did not indicate that it installed an "
-            ".egg-info directory. Only setup.py projects "
-            "generating .egg-info directories are supported."
-        ).format(req_description)
-        raise InstallationError(message)
-
-    new_lines = []
-    for line in record_lines:
-        filename = line.strip()
-        if os.path.isdir(filename):
-            filename += os.path.sep
-        new_lines.append(
-            os.path.relpath(prepend_root(filename), egg_info_dir)
-        )
-    new_lines.sort()
-    ensure_dir(egg_info_dir)
-    inst_files_path = os.path.join(egg_info_dir, 'installed-files.txt')
-    with open(inst_files_path, 'w') as f:
-        f.write('\n'.join(new_lines) + '\n')
-
-
-def install(
-    install_options,  # type: List[str]
-    global_options,  # type: Sequence[str]
-    root,  # type: Optional[str]
-    home,  # type: Optional[str]
-    prefix,  # type: Optional[str]
-    use_user_site,  # type: bool
-    pycompile,  # type: bool
-    scheme,  # type: Scheme
-    setup_py_path,  # type: str
-    isolated,  # type: bool
-    req_name,  # type: str
-    build_env,  # type: BuildEnvironment
-    unpacked_source_directory,  # type: str
-    req_description,  # type: str
-):
-    # type: (...) -> bool
-
-    header_dir = scheme.headers
-
-    with TempDirectory(kind="record") as temp_dir:
-        try:
-            record_filename = os.path.join(temp_dir.path, 'install-record.txt')
-            install_args = make_setuptools_install_args(
-                setup_py_path,
-                global_options=global_options,
-                install_options=install_options,
-                record_filename=record_filename,
-                root=root,
-                prefix=prefix,
-                header_dir=header_dir,
-                home=home,
-                use_user_site=use_user_site,
-                no_user_config=isolated,
-                pycompile=pycompile,
-            )
-
-            runner = runner_with_spinner_message(
-                f"Running setup.py install for {req_name}"
-            )
-            with indent_log(), build_env:
-                runner(
-                    cmd=install_args,
-                    cwd=unpacked_source_directory,
-                )
-
-            if not os.path.exists(record_filename):
-                logger.debug('Record file %s not found', record_filename)
-                # Signal to the caller that we didn't install the new package
-                return False
-
-        except Exception:
-            # Signal to the caller that we didn't install the new package
-            raise LegacyInstallFailure
-
-        # At this point, we have successfully installed the requirement.
-
-        # We intentionally do not use any encoding to read the file because
-        # setuptools writes the file using distutils.file_util.write_file,
-        # which does not specify an encoding.
-        with open(record_filename) as f:
-            record_lines = f.read().splitlines()
-
-    write_installed_files_from_setuptools_record(record_lines, root, req_description)
-    return True

venv/Lib/site-packages/pip/_internal/operations/install/wheel.py

@@ -22,6 +22,7 @@ from typing import (
     BinaryIO,
     Callable,
     Dict,
+    Generator,
     Iterable,
     Iterator,
     List,
@@ -38,11 +39,14 @@ from zipfile import ZipFile, ZipInfo
 from pip._vendor.distlib.scripts import ScriptMaker
 from pip._vendor.distlib.util import get_export_entry
 from pip._vendor.packaging.utils import canonicalize_name
-from pip._vendor.six import ensure_str, ensure_text, reraise
 
 from pip._internal.exceptions import InstallationError
 from pip._internal.locations import get_major_minor_version
-from pip._internal.metadata import BaseDistribution, get_wheel_distribution
+from pip._internal.metadata import (
+    BaseDistribution,
+    FilesystemWheel,
+    get_wheel_distribution,
+)
 from pip._internal.models.direct_url import DIRECT_URL_METADATA_NAME, DirectUrl
 from pip._internal.models.scheme import SCHEME_KEYS, Scheme
 from pip._internal.utils.filesystem import adjacent_tmp_file, replace
@@ -59,62 +63,55 @@ if TYPE_CHECKING:
     from typing import Protocol
 
     class File(Protocol):
-        src_record_path = None  # type: RecordPath
-        dest_path = None  # type: str
-        changed = None  # type: bool
+        src_record_path: "RecordPath"
+        dest_path: str
+        changed: bool
 
-        def save(self):
-            # type: () -> None
+        def save(self) -> None:
             pass
 
 
 logger = logging.getLogger(__name__)
 
-RecordPath = NewType('RecordPath', str)
+RecordPath = NewType("RecordPath", str)
 InstalledCSVRow = Tuple[RecordPath, str, Union[int, str]]
 
 
-def rehash(path, blocksize=1 << 20):
-    # type: (str, int) -> Tuple[str, str]
+def rehash(path: str, blocksize: int = 1 << 20) -> Tuple[str, str]:
     """Return (encoded_digest, length) for path using hashlib.sha256()"""
     h, length = hash_file(path, blocksize)
-    digest = 'sha256=' + urlsafe_b64encode(
-        h.digest()
-    ).decode('latin1').rstrip('=')
+    digest = "sha256=" + urlsafe_b64encode(h.digest()).decode("latin1").rstrip("=")
     return (digest, str(length))
 
 
-def csv_io_kwargs(mode):
-    # type: (str) -> Dict[str, Any]
+def csv_io_kwargs(mode: str) -> Dict[str, Any]:
     """Return keyword arguments to properly open a CSV file
     in the given mode.
     """
-    return {'mode': mode, 'newline': '', 'encoding': 'utf-8'}
+    return {"mode": mode, "newline": "", "encoding": "utf-8"}
 
 
-def fix_script(path):
-    # type: (str) -> bool
+def fix_script(path: str) -> bool:
     """Replace #!python with #!/path/to/python
     Return True if file was changed.
     """
     # XXX RECORD hashes will need to be updated
     assert os.path.isfile(path)
 
-    with open(path, 'rb') as script:
+    with open(path, "rb") as script:
         firstline = script.readline()
-        if not firstline.startswith(b'#!python'):
+        if not firstline.startswith(b"#!python"):
             return False
         exename = sys.executable.encode(sys.getfilesystemencoding())
-        firstline = b'#!' + exename + os.linesep.encode("ascii")
+        firstline = b"#!" + exename + os.linesep.encode("ascii")
         rest = script.read()
-    with open(path, 'wb') as script:
+    with open(path, "wb") as script:
         script.write(firstline)
         script.write(rest)
     return True
 
 
-def wheel_root_is_purelib(metadata):
-    # type: (Message) -> bool
+def wheel_root_is_purelib(metadata: Message) -> bool:
     return metadata.get("Root-Is-Purelib", "").lower() == "true"
 
 
@@ -129,8 +126,7 @@ def get_entrypoints(dist: BaseDistribution) -> Tuple[Dict[str, str], Dict[str, s
     return console_scripts, gui_scripts
 
 
-def message_about_scripts_not_on_PATH(scripts):
-    # type: (Sequence[str]) -> Optional[str]
+def message_about_scripts_not_on_PATH(scripts: Sequence[str]) -> Optional[str]:
     """Determine if any scripts are not on PATH and format a warning.
     Returns a warning message if one or more scripts are not on PATH,
     otherwise None.
@@ -139,7 +135,7 @@ def message_about_scripts_not_on_PATH(scripts):
         return None
 
     # Group scripts by the path they were installed in
-    grouped_by_dir = collections.defaultdict(set)  # type: Dict[str, Set[str]]
+    grouped_by_dir: Dict[str, Set[str]] = collections.defaultdict(set)
     for destfile in scripts:
         parent_dir = os.path.dirname(destfile)
         script_name = os.path.basename(destfile)
@@ -147,23 +143,26 @@ def message_about_scripts_not_on_PATH(scripts):
 
     # We don't want to warn for directories that are on PATH.
     not_warn_dirs = [
-        os.path.normcase(i).rstrip(os.sep) for i in
-        os.environ.get("PATH", "").split(os.pathsep)
+        os.path.normcase(os.path.normpath(i)).rstrip(os.sep)
+        for i in os.environ.get("PATH", "").split(os.pathsep)
     ]
     # If an executable sits with sys.executable, we don't warn for it.
     #     This covers the case of venv invocations without activating the venv.
-    not_warn_dirs.append(os.path.normcase(os.path.dirname(sys.executable)))
-    warn_for = {
-        parent_dir: scripts for parent_dir, scripts in grouped_by_dir.items()
-        if os.path.normcase(parent_dir) not in not_warn_dirs
-    }  # type: Dict[str, Set[str]]
+    not_warn_dirs.append(
+        os.path.normcase(os.path.normpath(os.path.dirname(sys.executable)))
+    )
+    warn_for: Dict[str, Set[str]] = {
+        parent_dir: scripts
+        for parent_dir, scripts in grouped_by_dir.items()
+        if os.path.normcase(os.path.normpath(parent_dir)) not in not_warn_dirs
+    }
     if not warn_for:
         return None
 
     # Format a message
     msg_lines = []
     for parent_dir, dir_scripts in warn_for.items():
-        sorted_scripts = sorted(dir_scripts)  # type: List[str]
+        sorted_scripts: List[str] = sorted(dir_scripts)
         if len(sorted_scripts) == 1:
             start_text = "script {} is".format(sorted_scripts[0])
         else:
@@ -172,8 +171,9 @@ def message_about_scripts_not_on_PATH(scripts):
             )
 
         msg_lines.append(
-            "The {} installed in '{}' which is not on PATH."
-            .format(start_text, parent_dir)
+            "The {} installed in '{}' which is not on PATH.".format(
+                start_text, parent_dir
+            )
         )
 
     last_line_fmt = (
@@ -200,8 +200,9 @@ def message_about_scripts_not_on_PATH(scripts):
     return "\n".join(msg_lines)
 
 
-def _normalized_outrows(outrows):
-    # type: (Iterable[InstalledCSVRow]) -> List[Tuple[str, str, str]]
+def _normalized_outrows(
+    outrows: Iterable[InstalledCSVRow],
+) -> List[Tuple[str, str, str]]:
     """Normalize the given rows of a RECORD file.
 
     Items in each row are converted into str. Rows are then sorted to make
@@ -221,69 +222,57 @@ def _normalized_outrows(outrows):
     # For additional background, see--
     # https://github.com/pypa/pip/issues/5868
     return sorted(
-        (ensure_str(record_path, encoding='utf-8'), hash_, str(size))
-        for record_path, hash_, size in outrows
+        (record_path, hash_, str(size)) for record_path, hash_, size in outrows
     )
 
 
-def _record_to_fs_path(record_path):
-    # type: (RecordPath) -> str
-    return record_path
+def _record_to_fs_path(record_path: RecordPath, lib_dir: str) -> str:
+    return os.path.join(lib_dir, record_path)
 
 
-def _fs_to_record_path(path, relative_to=None):
-    # type: (str, Optional[str]) -> RecordPath
-    if relative_to is not None:
-        # On Windows, do not handle relative paths if they belong to different
-        # logical disks
-        if os.path.splitdrive(path)[0].lower() == \
-                os.path.splitdrive(relative_to)[0].lower():
-            path = os.path.relpath(path, relative_to)
-    path = path.replace(os.path.sep, '/')
-    return cast('RecordPath', path)
+def _fs_to_record_path(path: str, lib_dir: str) -> RecordPath:
+    # On Windows, do not handle relative paths if they belong to different
+    # logical disks
+    if os.path.splitdrive(path)[0].lower() == os.path.splitdrive(lib_dir)[0].lower():
+        path = os.path.relpath(path, lib_dir)
 
-
-def _parse_record_path(record_column):
-    # type: (str) -> RecordPath
-    p = ensure_text(record_column, encoding='utf-8')
-    return cast('RecordPath', p)
+    path = path.replace(os.path.sep, "/")
+    return cast("RecordPath", path)
 
 
 def get_csv_rows_for_installed(
-    old_csv_rows,  # type: List[List[str]]
-    installed,  # type: Dict[RecordPath, RecordPath]
-    changed,  # type: Set[RecordPath]
-    generated,  # type: List[str]
-    lib_dir,  # type: str
-):
-    # type: (...) -> List[InstalledCSVRow]
+    old_csv_rows: List[List[str]],
+    installed: Dict[RecordPath, RecordPath],
+    changed: Set[RecordPath],
+    generated: List[str],
+    lib_dir: str,
+) -> List[InstalledCSVRow]:
     """
     :param installed: A map from archive RECORD path to installation RECORD
         path.
     """
-    installed_rows = []  # type: List[InstalledCSVRow]
+    installed_rows: List[InstalledCSVRow] = []
     for row in old_csv_rows:
         if len(row) > 3:
-            logger.warning('RECORD line has more than three elements: %s', row)
-        old_record_path = _parse_record_path(row[0])
+            logger.warning("RECORD line has more than three elements: %s", row)
+        old_record_path = cast("RecordPath", row[0])
         new_record_path = installed.pop(old_record_path, old_record_path)
         if new_record_path in changed:
-            digest, length = rehash(_record_to_fs_path(new_record_path))
+            digest, length = rehash(_record_to_fs_path(new_record_path, lib_dir))
         else:
-            digest = row[1] if len(row) > 1 else ''
-            length = row[2] if len(row) > 2 else ''
+            digest = row[1] if len(row) > 1 else ""
+            length = row[2] if len(row) > 2 else ""
         installed_rows.append((new_record_path, digest, length))
     for f in generated:
         path = _fs_to_record_path(f, lib_dir)
         digest, length = rehash(f)
         installed_rows.append((path, digest, length))
     for installed_record_path in installed.values():
-        installed_rows.append((installed_record_path, '', ''))
+        installed_rows.append((installed_record_path, "", ""))
     return installed_rows
 
 
-def get_console_script_specs(console):
-    # type: (Dict[str, str]) -> List[str]
+def get_console_script_specs(console: Dict[str, str]) -> List[str]:
     """
     Given the mapping from entrypoint name to callable, return the relevant
     console script specs.
@@ -326,62 +315,57 @@ def get_console_script_specs(console):
     # DEFAULT
     #   - The default behavior is to install pip, pipX, pipX.Y, easy_install
     #     and easy_install-X.Y.
-    pip_script = console.pop('pip', None)
+    pip_script = console.pop("pip", None)
     if pip_script:
         if "ENSUREPIP_OPTIONS" not in os.environ:
-            scripts_to_generate.append('pip = ' + pip_script)
+            scripts_to_generate.append("pip = " + pip_script)
 
         if os.environ.get("ENSUREPIP_OPTIONS", "") != "altinstall":
             scripts_to_generate.append(
-                'pip{} = {}'.format(sys.version_info[0], pip_script)
+                "pip{} = {}".format(sys.version_info[0], pip_script)
             )
 
-        scripts_to_generate.append(
-            f'pip{get_major_minor_version()} = {pip_script}'
-        )
+        scripts_to_generate.append(f"pip{get_major_minor_version()} = {pip_script}")
         # Delete any other versioned pip entry points
-        pip_ep = [k for k in console if re.match(r'pip(\d(\.\d)?)?$', k)]
+        pip_ep = [k for k in console if re.match(r"pip(\d+(\.\d+)?)?$", k)]
         for k in pip_ep:
             del console[k]
-    easy_install_script = console.pop('easy_install', None)
+    easy_install_script = console.pop("easy_install", None)
     if easy_install_script:
         if "ENSUREPIP_OPTIONS" not in os.environ:
-            scripts_to_generate.append(
-                'easy_install = ' + easy_install_script
-            )
+            scripts_to_generate.append("easy_install = " + easy_install_script)
 
         scripts_to_generate.append(
-            'easy_install-{} = {}'.format(
+            "easy_install-{} = {}".format(
                 get_major_minor_version(), easy_install_script
             )
         )
         # Delete any other versioned easy_install entry points
         easy_install_ep = [
-            k for k in console if re.match(r'easy_install(-\d\.\d)?$', k)
+            k for k in console if re.match(r"easy_install(-\d+\.\d+)?$", k)
         ]
         for k in easy_install_ep:
             del console[k]
 
     # Generate the console entry points specified in the wheel
-    scripts_to_generate.extend(starmap('{} = {}'.format, console.items()))
+    scripts_to_generate.extend(starmap("{} = {}".format, console.items()))
 
     return scripts_to_generate
 
 
 class ZipBackedFile:
-    def __init__(self, src_record_path, dest_path, zip_file):
-        # type: (RecordPath, str, ZipFile) -> None
+    def __init__(
+        self, src_record_path: RecordPath, dest_path: str, zip_file: ZipFile
+    ) -> None:
         self.src_record_path = src_record_path
         self.dest_path = dest_path
         self._zip_file = zip_file
         self.changed = False
 
-    def _getinfo(self):
-        # type: () -> ZipInfo
+    def _getinfo(self) -> ZipInfo:
         return self._zip_file.getinfo(self.src_record_path)
 
-    def save(self):
-        # type: () -> None
+    def save(self) -> None:
         # directory creation is lazy and after file filtering
         # to ensure we don't install empty dirs; empty dirs can't be
         # uninstalled.
@@ -410,22 +394,19 @@ class ZipBackedFile:
 
 
 class ScriptFile:
-    def __init__(self, file):
-        # type: (File) -> None
+    def __init__(self, file: "File") -> None:
         self._file = file
         self.src_record_path = self._file.src_record_path
         self.dest_path = self._file.dest_path
         self.changed = False
 
-    def save(self):
-        # type: () -> None
+    def save(self) -> None:
         self._file.save()
         self.changed = fix_script(self.dest_path)
 
 
 class MissingCallableSuffix(InstallationError):
-    def __init__(self, entry_point):
-        # type: (str) -> None
+    def __init__(self, entry_point: str) -> None:
         super().__init__(
             "Invalid script entry point: {} - A callable "
             "suffix is required. Cf https://packaging.python.org/"
@@ -434,31 +415,30 @@ class MissingCallableSuffix(InstallationError):
         )
 
 
-def _raise_for_invalid_entrypoint(specification):
-    # type: (str) -> None
+def _raise_for_invalid_entrypoint(specification: str) -> None:
     entry = get_export_entry(specification)
     if entry is not None and entry.suffix is None:
         raise MissingCallableSuffix(str(entry))
 
 
 class PipScriptMaker(ScriptMaker):
-    def make(self, specification, options=None):
-        # type: (str, Dict[str, Any]) -> List[str]
+    def make(
+        self, specification: str, options: Optional[Dict[str, Any]] = None
+    ) -> List[str]:
         _raise_for_invalid_entrypoint(specification)
         return super().make(specification, options)
 
 
 def _install_wheel(
-    name,  # type: str
-    wheel_zip,  # type: ZipFile
-    wheel_path,  # type: str
-    scheme,  # type: Scheme
-    pycompile=True,  # type: bool
-    warn_script_location=True,  # type: bool
-    direct_url=None,  # type: Optional[DirectUrl]
-    requested=False,  # type: bool
-):
-    # type: (...) -> None
+    name: str,
+    wheel_zip: ZipFile,
+    wheel_path: str,
+    scheme: Scheme,
+    pycompile: bool = True,
+    warn_script_location: bool = True,
+    direct_url: Optional[DirectUrl] = None,
+    requested: bool = False,
+) -> None:
     """Install a wheel.
 
     :param name: Name of the project to install
@@ -485,33 +465,23 @@ def _install_wheel(
     #   installed = files copied from the wheel to the destination
     #   changed = files changed while installing (scripts #! line typically)
     #   generated = files newly generated during the install (script wrappers)
-    installed = {}  # type: Dict[RecordPath, RecordPath]
-    changed = set()  # type: Set[RecordPath]
-    generated = []  # type: List[str]
+    installed: Dict[RecordPath, RecordPath] = {}
+    changed: Set[RecordPath] = set()
+    generated: List[str] = []
 
-    def record_installed(srcfile, destfile, modified=False):
-        # type: (RecordPath, str, bool) -> None
+    def record_installed(
+        srcfile: RecordPath, destfile: str, modified: bool = False
+    ) -> None:
         """Map archive RECORD paths to installation RECORD paths."""
         newpath = _fs_to_record_path(destfile, lib_dir)
         installed[srcfile] = newpath
         if modified:
-            changed.add(_fs_to_record_path(destfile))
+            changed.add(newpath)
 
-    def all_paths():
-        # type: () -> Iterable[RecordPath]
-        names = wheel_zip.namelist()
-        # If a flag is set, names may be unicode in Python 2. We convert to
-        # text explicitly so these are valid for lookup in RECORD.
-        decoded_names = map(ensure_text, names)
-        for name in decoded_names:
-            yield cast("RecordPath", name)
-
-    def is_dir_path(path):
-        # type: (RecordPath) -> bool
+    def is_dir_path(path: RecordPath) -> bool:
         return path.endswith("/")
 
-    def assert_no_path_traversal(dest_dir_path, target_path):
-        # type: (str, str) -> None
+    def assert_no_path_traversal(dest_dir_path: str, target_path: str) -> None:
         if not is_within_directory(dest_dir_path, target_path):
             message = (
                 "The wheel {!r} has a file {!r} trying to install"
@@ -521,10 +491,10 @@ def _install_wheel(
                 message.format(wheel_path, target_path, dest_dir_path)
             )
 
-    def root_scheme_file_maker(zip_file, dest):
-        # type: (ZipFile, str) -> Callable[[RecordPath], File]
-        def make_root_scheme_file(record_path):
-            # type: (RecordPath) -> File
+    def root_scheme_file_maker(
+        zip_file: ZipFile, dest: str
+    ) -> Callable[[RecordPath], "File"]:
+        def make_root_scheme_file(record_path: RecordPath) -> "File":
             normed_path = os.path.normpath(record_path)
             dest_path = os.path.join(dest, normed_path)
             assert_no_path_traversal(dest, dest_path)
@@ -532,17 +502,12 @@ def _install_wheel(
 
         return make_root_scheme_file
 
-    def data_scheme_file_maker(zip_file, scheme):
-        # type: (ZipFile, Scheme) -> Callable[[RecordPath], File]
-        scheme_paths = {}
-        for key in SCHEME_KEYS:
-            encoded_key = ensure_text(key)
-            scheme_paths[encoded_key] = ensure_text(
-                getattr(scheme, key), encoding=sys.getfilesystemencoding()
-            )
+    def data_scheme_file_maker(
+        zip_file: ZipFile, scheme: Scheme
+    ) -> Callable[[RecordPath], "File"]:
+        scheme_paths = {key: getattr(scheme, key) for key in SCHEME_KEYS}
 
-        def make_data_scheme_file(record_path):
-            # type: (RecordPath) -> File
+        def make_data_scheme_file(record_path: RecordPath) -> "File":
             normed_path = os.path.normpath(record_path)
             try:
                 _, scheme_key, dest_subpath = normed_path.split(os.path.sep, 2)
@@ -561,9 +526,7 @@ def _install_wheel(
                     "Unknown scheme key used in {}: {} (for file {!r}). .data"
                     " directory contents should be in subdirectories named"
                     " with a valid scheme key ({})"
-                ).format(
-                    wheel_path, scheme_key, record_path, valid_scheme_keys
-                )
+                ).format(wheel_path, scheme_key, record_path, valid_scheme_keys)
                 raise InstallationError(message)
 
             dest_path = os.path.join(scheme_path, dest_subpath)
@@ -572,30 +535,19 @@ def _install_wheel(
 
         return make_data_scheme_file
 
-    def is_data_scheme_path(path):
-        # type: (RecordPath) -> bool
+    def is_data_scheme_path(path: RecordPath) -> bool:
         return path.split("/", 1)[0].endswith(".data")
 
-    paths = all_paths()
+    paths = cast(List[RecordPath], wheel_zip.namelist())
     file_paths = filterfalse(is_dir_path, paths)
-    root_scheme_paths, data_scheme_paths = partition(
-        is_data_scheme_path, file_paths
-    )
+    root_scheme_paths, data_scheme_paths = partition(is_data_scheme_path, file_paths)
 
-    make_root_scheme_file = root_scheme_file_maker(
-        wheel_zip,
-        ensure_text(lib_dir, encoding=sys.getfilesystemencoding()),
-    )
-    files = map(make_root_scheme_file, root_scheme_paths)
+    make_root_scheme_file = root_scheme_file_maker(wheel_zip, lib_dir)
+    files: Iterator[File] = map(make_root_scheme_file, root_scheme_paths)
 
-    def is_script_scheme_path(path):
-        # type: (RecordPath) -> bool
+    def is_script_scheme_path(path: RecordPath) -> bool:
         parts = path.split("/", 2)
-        return (
-            len(parts) > 2 and
-            parts[0].endswith(".data") and
-            parts[1] == "scripts"
-        )
+        return len(parts) > 2 and parts[0].endswith(".data") and parts[1] == "scripts"
 
     other_scheme_paths, script_scheme_paths = partition(
         is_script_scheme_path, data_scheme_paths
@@ -606,30 +558,32 @@ def _install_wheel(
     files = chain(files, other_scheme_files)
 
     # Get the defined entry points
-    distribution = get_wheel_distribution(wheel_path, canonicalize_name(name))
+    distribution = get_wheel_distribution(
+        FilesystemWheel(wheel_path),
+        canonicalize_name(name),
+    )
     console, gui = get_entrypoints(distribution)
 
-    def is_entrypoint_wrapper(file):
-        # type: (File) -> bool
+    def is_entrypoint_wrapper(file: "File") -> bool:
         # EP, EP.exe and EP-script.py are scripts generated for
         # entry point EP by setuptools
         path = file.dest_path
         name = os.path.basename(path)
-        if name.lower().endswith('.exe'):
+        if name.lower().endswith(".exe"):
             matchname = name[:-4]
-        elif name.lower().endswith('-script.py'):
+        elif name.lower().endswith("-script.py"):
             matchname = name[:-10]
         elif name.lower().endswith(".pya"):
             matchname = name[:-4]
         else:
             matchname = name
         # Ignore setuptools-generated scripts
-        return (matchname in console or matchname in gui)
+        return matchname in console or matchname in gui
 
-    script_scheme_files = map(make_data_scheme_file, script_scheme_paths)
-    script_scheme_files = filterfalse(
-        is_entrypoint_wrapper, script_scheme_files
+    script_scheme_files: Iterator[File] = map(
+        make_data_scheme_file, script_scheme_paths
     )
+    script_scheme_files = filterfalse(is_entrypoint_wrapper, script_scheme_files)
     script_scheme_files = map(ScriptFile, script_scheme_files)
     files = chain(files, script_scheme_files)
 
@@ -637,8 +591,7 @@ def _install_wheel(
         file.save()
         record_installed(file.src_record_path, file.dest_path, file.changed)
 
-    def pyc_source_file_paths():
-        # type: () -> Iterator[str]
+    def pyc_source_file_paths() -> Generator[str, None, None]:
         # We de-duplicate installation paths, since there can be overlap (e.g.
         # file in .data maps to same location as file in wheel root).
         # Sorting installation paths makes it easier to reproduce and debug
@@ -647,30 +600,21 @@ def _install_wheel(
             full_installed_path = os.path.join(lib_dir, installed_path)
             if not os.path.isfile(full_installed_path):
                 continue
-            if not full_installed_path.endswith('.py'):
+            if not full_installed_path.endswith(".py"):
                 continue
             yield full_installed_path
 
-    def pyc_output_path(path):
-        # type: (str) -> str
-        """Return the path the pyc file would have been written to.
-        """
+    def pyc_output_path(path: str) -> str:
+        """Return the path the pyc file would have been written to."""
         return importlib.util.cache_from_source(path)
 
     # Compile all of the pyc files for the installed files
     if pycompile:
         with captured_stdout() as stdout:
             with warnings.catch_warnings():
-                warnings.filterwarnings('ignore')
+                warnings.filterwarnings("ignore")
                 for path in pyc_source_file_paths():
-                    # Python 2's `compileall.compile_file` requires a str in
-                    # error cases, so we must convert to the native type.
-                    path_arg = ensure_str(
-                        path, encoding=sys.getfilesystemencoding()
-                    )
-                    success = compileall.compile_file(
-                        path_arg, force=True, quiet=True
-                    )
+                    success = compileall.compile_file(path, force=True, quiet=True)
                     if success:
                         pyc_path = pyc_output_path(path)
                         assert os.path.exists(pyc_path)
@@ -689,7 +633,7 @@ def _install_wheel(
     # Ensure we don't generate any variants for scripts because this is almost
     # never what somebody wants.
     # See https://bitbucket.org/pypa/distlib/issue/35/
-    maker.variants = {''}
+    maker.variants = {""}
 
     # This is required because otherwise distlib creates scripts that are not
     # executable.
@@ -699,14 +643,12 @@ def _install_wheel(
     # Generate the console and GUI entry points specified in the wheel
     scripts_to_generate = get_console_script_specs(console)
 
-    gui_scripts_to_generate = list(starmap('{} = {}'.format, gui.items()))
+    gui_scripts_to_generate = list(starmap("{} = {}".format, gui.items()))
 
     generated_console_scripts = maker.make_multiple(scripts_to_generate)
     generated.extend(generated_console_scripts)
 
-    generated.extend(
-        maker.make_multiple(gui_scripts_to_generate, {'gui': True})
-    )
+    generated.extend(maker.make_multiple(gui_scripts_to_generate, {"gui": True}))
 
     if warn_script_location:
         msg = message_about_scripts_not_on_PATH(generated_console_scripts)
@@ -716,8 +658,7 @@ def _install_wheel(
     generated_file_mode = 0o666 & ~current_umask()
 
     @contextlib.contextmanager
-    def _generate_file(path, **kwargs):
-        # type: (str, **Any) -> Iterator[BinaryIO]
+    def _generate_file(path: str, **kwargs: Any) -> Generator[BinaryIO, None, None]:
         with adjacent_tmp_file(path, **kwargs) as f:
             yield f
         os.chmod(f.name, generated_file_mode)
@@ -726,9 +667,9 @@ def _install_wheel(
     dest_info_dir = os.path.join(lib_dir, info_dir)
 
     # Record pip as the installer
-    installer_path = os.path.join(dest_info_dir, 'INSTALLER')
+    installer_path = os.path.join(dest_info_dir, "INSTALLER")
     with _generate_file(installer_path) as installer_file:
-        installer_file.write(b'pip\n')
+        installer_file.write(b"pip\n")
     generated.append(installer_path)
 
     # Record the PEP 610 direct URL reference
@@ -740,12 +681,12 @@ def _install_wheel(
 
     # Record the REQUESTED file
     if requested:
-        requested_path = os.path.join(dest_info_dir, 'REQUESTED')
+        requested_path = os.path.join(dest_info_dir, "REQUESTED")
         with open(requested_path, "wb"):
             pass
         generated.append(requested_path)
 
-    record_text = distribution.read_text('RECORD')
+    record_text = distribution.read_text("RECORD")
     record_rows = list(csv.reader(record_text.splitlines()))
 
     rows = get_csv_rows_for_installed(
@@ -753,42 +694,38 @@ def _install_wheel(
         installed=installed,
         changed=changed,
         generated=generated,
-        lib_dir=lib_dir)
+        lib_dir=lib_dir,
+    )
 
     # Record details of all files installed
-    record_path = os.path.join(dest_info_dir, 'RECORD')
+    record_path = os.path.join(dest_info_dir, "RECORD")
 
-    with _generate_file(record_path, **csv_io_kwargs('w')) as record_file:
-        # The type mypy infers for record_file is different for Python 3
-        # (typing.IO[Any]) and Python 2 (typing.BinaryIO). We explicitly
-        # cast to typing.IO[str] as a workaround.
-        writer = csv.writer(cast('IO[str]', record_file))
+    with _generate_file(record_path, **csv_io_kwargs("w")) as record_file:
+        # Explicitly cast to typing.IO[str] as a workaround for the mypy error:
+        # "writer" has incompatible type "BinaryIO"; expected "_Writer"
+        writer = csv.writer(cast("IO[str]", record_file))
         writer.writerows(_normalized_outrows(rows))
 
 
 @contextlib.contextmanager
-def req_error_context(req_description):
-    # type: (str) -> Iterator[None]
+def req_error_context(req_description: str) -> Generator[None, None, None]:
     try:
         yield
     except InstallationError as e:
         message = "For req: {}. {}".format(req_description, e.args[0])
-        reraise(
-            InstallationError, InstallationError(message), sys.exc_info()[2]
-        )
+        raise InstallationError(message) from e
 
 
 def install_wheel(
-    name,  # type: str
-    wheel_path,  # type: str
-    scheme,  # type: Scheme
-    req_description,  # type: str
-    pycompile=True,  # type: bool
-    warn_script_location=True,  # type: bool
-    direct_url=None,  # type: Optional[DirectUrl]
-    requested=False,  # type: bool
-):
-    # type: (...) -> None
+    name: str,
+    wheel_path: str,
+    scheme: Scheme,
+    req_description: str,
+    pycompile: bool = True,
+    warn_script_location: bool = True,
+    direct_url: Optional[DirectUrl] = None,
+    requested: bool = False,
+) -> None:
     with ZipFile(wheel_path, allowZip64=True) as z:
         with req_error_context(req_description):
             _install_wheel(

venv/Lib/site-packages/pip/_internal/operations/prepare.py

@@ -8,10 +8,9 @@ import logging
 import mimetypes
 import os
 import shutil
-from typing import Dict, Iterable, List, Optional, Tuple
+from typing import Dict, Iterable, List, Optional
 
 from pip._vendor.packaging.utils import canonicalize_name
-from pip._vendor.pkg_resources import Distribution
 
 from pip._internal.distributions import make_distribution_for_install_requirement
 from pip._internal.distributions.installed import InstalledDistribution
@@ -20,11 +19,14 @@ from pip._internal.exceptions import (
     HashMismatch,
     HashUnpinned,
     InstallationError,
+    MetadataInconsistent,
     NetworkConnectionError,
     PreviousBuildDirError,
     VcsHashUnsupported,
 )
 from pip._internal.index.package_finder import PackageFinder
+from pip._internal.metadata import BaseDistribution, get_metadata_distribution
+from pip._internal.models.direct_url import ArchiveInfo
 from pip._internal.models.link import Link
 from pip._internal.models.wheel import Wheel
 from pip._internal.network.download import BatchDownloader, Downloader
@@ -33,13 +35,20 @@ from pip._internal.network.lazy_wheel import (
     dist_from_wheel_url,
 )
 from pip._internal.network.session import PipSession
+from pip._internal.operations.build.build_tracker import BuildTracker
 from pip._internal.req.req_install import InstallRequirement
-from pip._internal.req.req_tracker import RequirementTracker
-from pip._internal.utils.deprecation import deprecated
-from pip._internal.utils.filesystem import copy2_fixed
+from pip._internal.utils.direct_url_helpers import (
+    direct_url_for_editable,
+    direct_url_from_link,
+)
 from pip._internal.utils.hashes import Hashes, MissingHashes
 from pip._internal.utils.logging import indent_log
-from pip._internal.utils.misc import display_path, hide_url, is_installable_dir, rmtree
+from pip._internal.utils.misc import (
+    display_path,
+    hash_file,
+    hide_url,
+    is_installable_dir,
+)
 from pip._internal.utils.temp_dir import TempDirectory
 from pip._internal.utils.unpacking import unpack_file
 from pip._internal.vcs import vcs
@@ -48,30 +57,29 @@ logger = logging.getLogger(__name__)
 
 
 def _get_prepared_distribution(
-    req,  # type: InstallRequirement
-    req_tracker,  # type: RequirementTracker
-    finder,  # type: PackageFinder
-    build_isolation,  # type: bool
-):
-    # type: (...) -> Distribution
+    req: InstallRequirement,
+    build_tracker: BuildTracker,
+    finder: PackageFinder,
+    build_isolation: bool,
+    check_build_deps: bool,
+) -> BaseDistribution:
     """Prepare a distribution for installation."""
     abstract_dist = make_distribution_for_install_requirement(req)
-    with req_tracker.track(req):
-        abstract_dist.prepare_distribution_metadata(finder, build_isolation)
-    return abstract_dist.get_pkg_resources_distribution()
+    with build_tracker.track(req):
+        abstract_dist.prepare_distribution_metadata(
+            finder, build_isolation, check_build_deps
+        )
+    return abstract_dist.get_metadata_distribution()
 
 
-def unpack_vcs_link(link, location):
-    # type: (Link, str) -> None
+def unpack_vcs_link(link: Link, location: str, verbosity: int) -> None:
     vcs_backend = vcs.get_backend_for_scheme(link.scheme)
     assert vcs_backend is not None
-    vcs_backend.unpack(location, url=hide_url(link.url))
+    vcs_backend.unpack(location, url=hide_url(link.url), verbosity=verbosity)
 
 
 class File:
-
-    def __init__(self, path, content_type):
-        # type: (str, Optional[str]) -> None
+    def __init__(self, path: str, content_type: Optional[str]) -> None:
         self.path = path
         if content_type is None:
             self.content_type = mimetypes.guess_type(path)[0]
@@ -80,19 +88,16 @@ class File:
 
 
 def get_http_url(
-    link,  # type: Link
-    download,  # type: Downloader
-    download_dir=None,  # type: Optional[str]
-    hashes=None,  # type: Optional[Hashes]
-):
-    # type: (...) -> File
+    link: Link,
+    download: Downloader,
+    download_dir: Optional[str] = None,
+    hashes: Optional[Hashes] = None,
+) -> File:
     temp_dir = TempDirectory(kind="unpack", globally_managed=True)
     # If a download dir is specified, is the file already downloaded there?
     already_downloaded_path = None
     if download_dir:
-        already_downloaded_path = _check_download_dir(
-            link, download_dir, hashes
-        )
+        already_downloaded_path = _check_download_dir(link, download_dir, hashes)
 
     if already_downloaded_path:
         from_path = already_downloaded_path
@@ -106,72 +111,14 @@ def get_http_url(
     return File(from_path, content_type)
 
 
-def _copy2_ignoring_special_files(src, dest):
-    # type: (str, str) -> None
-    """Copying special files is not supported, but as a convenience to users
-    we skip errors copying them. This supports tools that may create e.g.
-    socket files in the project source directory.
-    """
-    try:
-        copy2_fixed(src, dest)
-    except shutil.SpecialFileError as e:
-        # SpecialFileError may be raised due to either the source or
-        # destination. If the destination was the cause then we would actually
-        # care, but since the destination directory is deleted prior to
-        # copy we ignore all of them assuming it is caused by the source.
-        logger.warning(
-            "Ignoring special file error '%s' encountered copying %s to %s.",
-            str(e),
-            src,
-            dest,
-        )
-
-
-def _copy_source_tree(source, target):
-    # type: (str, str) -> None
-    target_abspath = os.path.abspath(target)
-    target_basename = os.path.basename(target_abspath)
-    target_dirname = os.path.dirname(target_abspath)
-
-    def ignore(d, names):
-        # type: (str, List[str]) -> List[str]
-        skipped = []  # type: List[str]
-        if d == source:
-            # Pulling in those directories can potentially be very slow,
-            # exclude the following directories if they appear in the top
-            # level dir (and only it).
-            # See discussion at https://github.com/pypa/pip/pull/6770
-            skipped += ['.tox', '.nox']
-        if os.path.abspath(d) == target_dirname:
-            # Prevent an infinite recursion if the target is in source.
-            # This can happen when TMPDIR is set to ${PWD}/...
-            # and we copy PWD to TMPDIR.
-            skipped += [target_basename]
-        return skipped
-
-    shutil.copytree(
-        source,
-        target,
-        ignore=ignore,
-        symlinks=True,
-        copy_function=_copy2_ignoring_special_files,
-    )
-
-
 def get_file_url(
-    link,  # type: Link
-    download_dir=None,  # type: Optional[str]
-    hashes=None  # type: Optional[Hashes]
-):
-    # type: (...) -> File
-    """Get file and optionally check its hash.
-    """
+    link: Link, download_dir: Optional[str] = None, hashes: Optional[Hashes] = None
+) -> File:
+    """Get file and optionally check its hash."""
     # If a download dir is specified, is the file already there and valid?
     already_downloaded_path = None
     if download_dir:
-        already_downloaded_path = _check_download_dir(
-            link, download_dir, hashes
-        )
+        already_downloaded_path = _check_download_dir(link, download_dir, hashes)
 
     if already_downloaded_path:
         from_path = already_downloaded_path
@@ -189,13 +136,13 @@ def get_file_url(
 
 
 def unpack_url(
-    link,  # type: Link
-    location,  # type: str
-    download,  # type: Downloader
-    download_dir=None,  # type: Optional[str]
-    hashes=None,  # type: Optional[Hashes]
-):
-    # type: (...) -> Optional[File]
+    link: Link,
+    location: str,
+    download: Downloader,
+    verbosity: int,
+    download_dir: Optional[str] = None,
+    hashes: Optional[Hashes] = None,
+) -> Optional[File]:
     """Unpack link into location, downloading if required.
 
     :param hashes: A Hashes object, one of whose embedded hashes must match,
@@ -205,30 +152,10 @@ def unpack_url(
     """
     # non-editable vcs urls
     if link.is_vcs:
-        unpack_vcs_link(link, location)
+        unpack_vcs_link(link, location, verbosity=verbosity)
         return None
 
-    # Once out-of-tree-builds are no longer supported, could potentially
-    # replace the below condition with `assert not link.is_existing_dir`
-    # - unpack_url does not need to be called for in-tree-builds.
-    #
-    # As further cleanup, _copy_source_tree and accompanying tests can
-    # be removed.
-    if link.is_existing_dir():
-        deprecated(
-            "A future pip version will change local packages to be built "
-            "in-place without first copying to a temporary directory. "
-            "We recommend you use --use-feature=in-tree-build to test "
-            "your packages with this new behavior before it becomes the "
-            "default.\n",
-            replacement=None,
-            gone_in="21.3",
-            issue=7555
-        )
-        if os.path.isdir(location):
-            rmtree(location)
-        _copy_source_tree(link.file_path, location)
-        return None
+    assert not link.is_existing_dir()
 
     # file urls
     if link.is_file:
@@ -251,10 +178,14 @@ def unpack_url(
     return file
 
 
-def _check_download_dir(link, download_dir, hashes):
-    # type: (Link, str, Optional[Hashes]) -> Optional[str]
-    """ Check download_dir for previously downloaded file with correct hash
-        If a correct file is found return its path else None
+def _check_download_dir(
+    link: Link,
+    download_dir: str,
+    hashes: Optional[Hashes],
+    warn_on_hash_mismatch: bool = True,
+) -> Optional[str]:
+    """Check download_dir for previously downloaded file with correct hash
+    If a correct file is found return its path else None
     """
     download_path = os.path.join(download_dir, link.filename)
 
@@ -262,46 +193,45 @@ def _check_download_dir(link, download_dir, hashes):
         return None
 
     # If already downloaded, does its hash match?
-    logger.info('File was already downloaded %s', download_path)
+    logger.info("File was already downloaded %s", download_path)
     if hashes:
         try:
             hashes.check_against_path(download_path)
         except HashMismatch:
-            logger.warning(
-                'Previously-downloaded file %s has bad hash. '
-                'Re-downloading.',
-                download_path
-            )
+            if warn_on_hash_mismatch:
+                logger.warning(
+                    "Previously-downloaded file %s has bad hash. Re-downloading.",
+                    download_path,
+                )
             os.unlink(download_path)
             return None
     return download_path
 
 
 class RequirementPreparer:
-    """Prepares a Requirement
-    """
+    """Prepares a Requirement"""
 
     def __init__(
         self,
-        build_dir,  # type: str
-        download_dir,  # type: Optional[str]
-        src_dir,  # type: str
-        build_isolation,  # type: bool
-        req_tracker,  # type: RequirementTracker
-        session,  # type: PipSession
-        progress_bar,  # type: str
-        finder,  # type: PackageFinder
-        require_hashes,  # type: bool
-        use_user_site,  # type: bool
-        lazy_wheel,  # type: bool
-        in_tree_build,  # type: bool
-    ):
-        # type: (...) -> None
+        build_dir: str,
+        download_dir: Optional[str],
+        src_dir: str,
+        build_isolation: bool,
+        check_build_deps: bool,
+        build_tracker: BuildTracker,
+        session: PipSession,
+        progress_bar: str,
+        finder: PackageFinder,
+        require_hashes: bool,
+        use_user_site: bool,
+        lazy_wheel: bool,
+        verbosity: int,
+    ) -> None:
         super().__init__()
 
         self.src_dir = src_dir
         self.build_dir = build_dir
-        self.req_tracker = req_tracker
+        self.build_tracker = build_tracker
         self._session = session
         self._download = Downloader(session, progress_bar)
         self._batch_download = BatchDownloader(session, progress_bar)
@@ -314,6 +244,9 @@ class RequirementPreparer:
         # Is build isolation allowed?
         self.build_isolation = build_isolation
 
+        # Should check build dependencies?
+        self.check_build_deps = check_build_deps
+
         # Should hash-checking be required?
         self.require_hashes = require_hashes
 
@@ -323,35 +256,45 @@ class RequirementPreparer:
         # Should wheels be downloaded lazily?
         self.use_lazy_wheel = lazy_wheel
 
-        # Should in-tree builds be used for local paths?
-        self.in_tree_build = in_tree_build
+        # How verbose should underlying tooling be?
+        self.verbosity = verbosity
 
-        # Memoized downloaded files, as mapping of url: (path, mime type)
-        self._downloaded = {}  # type: Dict[str, Tuple[str, str]]
+        # Memoized downloaded files, as mapping of url: path.
+        self._downloaded: Dict[str, str] = {}
 
         # Previous "header" printed for a link-based InstallRequirement
         self._previous_requirement_header = ("", "")
 
-    def _log_preparing_link(self, req):
-        # type: (InstallRequirement) -> None
+    def _log_preparing_link(self, req: InstallRequirement) -> None:
         """Provide context for the requirement being prepared."""
-        if req.link.is_file and not req.original_link_is_in_wheel_cache:
+        if req.link.is_file and not req.is_wheel_from_cache:
             message = "Processing %s"
             information = str(display_path(req.link.file_path))
         else:
             message = "Collecting %s"
             information = str(req.req or req)
 
+        # If we used req.req, inject requirement source if available (this
+        # would already be included if we used req directly)
+        if req.req and req.comes_from:
+            if isinstance(req.comes_from, str):
+                comes_from: Optional[str] = req.comes_from
+            else:
+                comes_from = req.comes_from.from_path()
+            if comes_from:
+                information += f" (from {comes_from})"
+
         if (message, information) != self._previous_requirement_header:
             self._previous_requirement_header = (message, information)
             logger.info(message, information)
 
-        if req.original_link_is_in_wheel_cache:
+        if req.is_wheel_from_cache:
             with indent_log():
                 logger.info("Using cached %s", req.link.filename)
 
-    def _ensure_link_req_src_dir(self, req, parallel_builds):
-        # type: (InstallRequirement, bool) -> None
+    def _ensure_link_req_src_dir(
+        self, req: InstallRequirement, parallel_builds: bool
+    ) -> None:
         """Ensure source_dir of a linked InstallRequirement."""
         # Since source_dir is only set for editable requirements.
         if req.link.is_wheel:
@@ -359,7 +302,7 @@ class RequirementPreparer:
             # directory.
             return
         assert req.source_dir is None
-        if req.link.is_existing_dir() and self.in_tree_build:
+        if req.link.is_existing_dir():
             # build local directories in-tree
             req.source_dir = req.link.file_path
             return
@@ -376,6 +319,7 @@ class RequirementPreparer:
         # installation.
         # FIXME: this won't upgrade when there's an existing
         # package unpacked in `req.source_dir`
+        # TODO: this check is now probably dead code
         if is_installable_dir(req.source_dir):
             raise PreviousBuildDirError(
                 "pip can't proceed with requirements '{}' due to a"
@@ -385,8 +329,7 @@ class RequirementPreparer:
                 "Please delete it and try again.".format(req, req.source_dir)
             )
 
-    def _get_linked_req_hashes(self, req):
-        # type: (InstallRequirement) -> Hashes
+    def _get_linked_req_hashes(self, req: InstallRequirement) -> Hashes:
         # By the time this is called, the requirement's link should have
         # been checked so we can tell what kind of requirements req is
         # and raise some more informative errors than otherwise.
@@ -418,18 +361,72 @@ class RequirementPreparer:
         # showing the user what the hash should be.
         return req.hashes(trust_internet=False) or MissingHashes()
 
-    def _fetch_metadata_using_lazy_wheel(self, link):
-        # type: (Link) -> Optional[Distribution]
-        """Fetch metadata using lazy wheel, if possible."""
-        if not self.use_lazy_wheel:
-            return None
+    def _fetch_metadata_only(
+        self,
+        req: InstallRequirement,
+    ) -> Optional[BaseDistribution]:
         if self.require_hashes:
-            logger.debug('Lazy wheel is not used as hash checking is required')
+            logger.debug(
+                "Metadata-only fetching is not used as hash checking is required",
+            )
+            return None
+        # Try PEP 658 metadata first, then fall back to lazy wheel if unavailable.
+        return self._fetch_metadata_using_link_data_attr(
+            req
+        ) or self._fetch_metadata_using_lazy_wheel(req.link)
+
+    def _fetch_metadata_using_link_data_attr(
+        self,
+        req: InstallRequirement,
+    ) -> Optional[BaseDistribution]:
+        """Fetch metadata from the data-dist-info-metadata attribute, if possible."""
+        # (1) Get the link to the metadata file, if provided by the backend.
+        metadata_link = req.link.metadata_link()
+        if metadata_link is None:
+            return None
+        assert req.req is not None
+        logger.info(
+            "Obtaining dependency information for %s from %s",
+            req.req,
+            metadata_link,
+        )
+        # (2) Download the contents of the METADATA file, separate from the dist itself.
+        metadata_file = get_http_url(
+            metadata_link,
+            self._download,
+            hashes=metadata_link.as_hashes(),
+        )
+        with open(metadata_file.path, "rb") as f:
+            metadata_contents = f.read()
+        # (3) Generate a dist just from those file contents.
+        metadata_dist = get_metadata_distribution(
+            metadata_contents,
+            req.link.filename,
+            req.req.name,
+        )
+        # (4) Ensure the Name: field from the METADATA file matches the name from the
+        #     install requirement.
+        #
+        #     NB: raw_name will fall back to the name from the install requirement if
+        #     the Name: field is not present, but it's noted in the raw_name docstring
+        #     that that should NEVER happen anyway.
+        if metadata_dist.raw_name != req.req.name:
+            raise MetadataInconsistent(
+                req, "Name", req.req.name, metadata_dist.raw_name
+            )
+        return metadata_dist
+
+    def _fetch_metadata_using_lazy_wheel(
+        self,
+        link: Link,
+    ) -> Optional[BaseDistribution]:
+        """Fetch metadata using lazy wheel, if possible."""
+        # --use-feature=fast-deps must be provided.
+        if not self.use_lazy_wheel:
             return None
         if link.is_file or not link.is_wheel:
             logger.debug(
-                'Lazy wheel is not used as '
-                '%r does not points to a remote wheel',
+                "Lazy wheel is not used as %r does not point to a remote wheel",
                 link,
             )
             return None
@@ -437,22 +434,22 @@ class RequirementPreparer:
         wheel = Wheel(link.filename)
         name = canonicalize_name(wheel.name)
         logger.info(
-            'Obtaining dependency information from %s %s',
-            name, wheel.version,
+            "Obtaining dependency information from %s %s",
+            name,
+            wheel.version,
         )
-        url = link.url.split('#', 1)[0]
+        url = link.url.split("#", 1)[0]
         try:
             return dist_from_wheel_url(name, url, self._session)
         except HTTPRangeRequestUnsupported:
-            logger.debug('%s does not support range requests', url)
+            logger.debug("%s does not support range requests", url)
             return None
 
     def _complete_partial_requirements(
         self,
-        partially_downloaded_reqs,  # type: Iterable[InstallRequirement]
-        parallel_builds=False,      # type: bool
-    ):
-        # type: (...) -> None
+        partially_downloaded_reqs: Iterable[InstallRequirement],
+        parallel_builds: bool = False,
+    ) -> None:
         """Download any requirements which were only fetched by metadata."""
         # Download to a temporary directory. These will be copied over as
         # needed for downstream 'download', 'wheel', and 'install' commands.
@@ -461,7 +458,7 @@ class RequirementPreparer:
         # Map each link to the requirement that owns it. This allows us to set
         # `req.local_file_path` on the appropriate requirement after passing
         # all the links at once into BatchDownloader.
-        links_to_fully_download = {}  # type: Dict[Link, InstallRequirement]
+        links_to_fully_download: Dict[Link, InstallRequirement] = {}
         for req in partially_downloaded_reqs:
             assert req.link
             links_to_fully_download[req.link] = req
@@ -480,35 +477,47 @@ class RequirementPreparer:
         for req in partially_downloaded_reqs:
             self._prepare_linked_requirement(req, parallel_builds)
 
-    def prepare_linked_requirement(self, req, parallel_builds=False):
-        # type: (InstallRequirement, bool) -> Distribution
+    def prepare_linked_requirement(
+        self, req: InstallRequirement, parallel_builds: bool = False
+    ) -> BaseDistribution:
         """Prepare a requirement to be obtained from req.link."""
         assert req.link
-        link = req.link
         self._log_preparing_link(req)
         with indent_log():
             # Check if the relevant file is already available
             # in the download directory
             file_path = None
-            if self.download_dir is not None and link.is_wheel:
+            if self.download_dir is not None and req.link.is_wheel:
                 hashes = self._get_linked_req_hashes(req)
-                file_path = _check_download_dir(req.link, self.download_dir, hashes)
+                file_path = _check_download_dir(
+                    req.link,
+                    self.download_dir,
+                    hashes,
+                    # When a locally built wheel has been found in cache, we don't warn
+                    # about re-downloading when the already downloaded wheel hash does
+                    # not match. This is because the hash must be checked against the
+                    # original link, not the cached link. It that case the already
+                    # downloaded file will be removed and re-fetched from cache (which
+                    # implies a hash check against the cache entry's origin.json).
+                    warn_on_hash_mismatch=not req.is_wheel_from_cache,
+                )
 
             if file_path is not None:
                 # The file is already available, so mark it as downloaded
-                self._downloaded[req.link.url] = file_path, None
+                self._downloaded[req.link.url] = file_path
             else:
                 # The file is not available, attempt to fetch only metadata
-                wheel_dist = self._fetch_metadata_using_lazy_wheel(link)
-                if wheel_dist is not None:
+                metadata_dist = self._fetch_metadata_only(req)
+                if metadata_dist is not None:
                     req.needs_more_preparation = True
-                    return wheel_dist
+                    return metadata_dist
 
             # None of the optimizations worked, fully prepare the requirement
             return self._prepare_linked_requirement(req, parallel_builds)
 
-    def prepare_linked_requirements_more(self, reqs, parallel_builds=False):
-        # type: (Iterable[InstallRequirement], bool) -> None
+    def prepare_linked_requirements_more(
+        self, reqs: Iterable[InstallRequirement], parallel_builds: bool = False
+    ) -> None:
         """Prepare linked requirements more, if needed."""
         reqs = [req for req in reqs if req.needs_more_preparation]
         for req in reqs:
@@ -517,12 +526,12 @@ class RequirementPreparer:
                 hashes = self._get_linked_req_hashes(req)
                 file_path = _check_download_dir(req.link, self.download_dir, hashes)
                 if file_path is not None:
-                    self._downloaded[req.link.url] = file_path, None
+                    self._downloaded[req.link.url] = file_path
                     req.needs_more_preparation = False
 
         # Prepare requirements we found were already downloaded for some
         # reason. The other downloads will be completed separately.
-        partially_downloaded_reqs = []  # type: List[InstallRequirement]
+        partially_downloaded_reqs: List[InstallRequirement] = []
         for req in reqs:
             if req.needs_more_preparation:
                 partially_downloaded_reqs.append(req)
@@ -532,35 +541,87 @@ class RequirementPreparer:
         # TODO: separate this part out from RequirementPreparer when the v1
         # resolver can be removed!
         self._complete_partial_requirements(
-            partially_downloaded_reqs, parallel_builds=parallel_builds,
+            partially_downloaded_reqs,
+            parallel_builds=parallel_builds,
         )
 
-    def _prepare_linked_requirement(self, req, parallel_builds):
-        # type: (InstallRequirement, bool) -> Distribution
+    def _prepare_linked_requirement(
+        self, req: InstallRequirement, parallel_builds: bool
+    ) -> BaseDistribution:
         assert req.link
         link = req.link
 
-        self._ensure_link_req_src_dir(req, parallel_builds)
         hashes = self._get_linked_req_hashes(req)
 
-        if link.is_existing_dir() and self.in_tree_build:
+        if hashes and req.is_wheel_from_cache:
+            assert req.download_info is not None
+            assert link.is_wheel
+            assert link.is_file
+            # We need to verify hashes, and we have found the requirement in the cache
+            # of locally built wheels.
+            if (
+                isinstance(req.download_info.info, ArchiveInfo)
+                and req.download_info.info.hashes
+                and hashes.has_one_of(req.download_info.info.hashes)
+            ):
+                # At this point we know the requirement was built from a hashable source
+                # artifact, and we verified that the cache entry's hash of the original
+                # artifact matches one of the hashes we expect. We don't verify hashes
+                # against the cached wheel, because the wheel is not the original.
+                hashes = None
+            else:
+                logger.warning(
+                    "The hashes of the source archive found in cache entry "
+                    "don't match, ignoring cached built wheel "
+                    "and re-downloading source."
+                )
+                req.link = req.cached_wheel_source_link
+                link = req.link
+
+        self._ensure_link_req_src_dir(req, parallel_builds)
+
+        if link.is_existing_dir():
             local_file = None
         elif link.url not in self._downloaded:
             try:
                 local_file = unpack_url(
-                    link, req.source_dir, self._download,
-                    self.download_dir, hashes
+                    link,
+                    req.source_dir,
+                    self._download,
+                    self.verbosity,
+                    self.download_dir,
+                    hashes,
                 )
             except NetworkConnectionError as exc:
                 raise InstallationError(
-                    'Could not install requirement {} because of HTTP '
-                    'error {} for URL {}'.format(req, exc, link)
+                    "Could not install requirement {} because of HTTP "
+                    "error {} for URL {}".format(req, exc, link)
                 )
         else:
-            file_path, content_type = self._downloaded[link.url]
+            file_path = self._downloaded[link.url]
             if hashes:
                 hashes.check_against_path(file_path)
-            local_file = File(file_path, content_type)
+            local_file = File(file_path, content_type=None)
+
+        # If download_info is set, we got it from the wheel cache.
+        if req.download_info is None:
+            # Editables don't go through this function (see
+            # prepare_editable_requirement).
+            assert not req.editable
+            req.download_info = direct_url_from_link(link, req.source_dir)
+            # Make sure we have a hash in download_info. If we got it as part of the
+            # URL, it will have been verified and we can rely on it. Otherwise we
+            # compute it from the downloaded file.
+            # FIXME: https://github.com/pypa/pip/issues/11943
+            if (
+                isinstance(req.download_info.info, ArchiveInfo)
+                and not req.download_info.info.hashes
+                and local_file
+            ):
+                hash = hash_file(local_file.path)[0].hexdigest()
+                # We populate info.hash for backward compatibility.
+                # This will automatically populate info.hashes.
+                req.download_info.info.hash = f"sha256={hash}"
 
         # For use in later processing,
         # preserve the file path on the requirement.
@@ -568,12 +629,15 @@ class RequirementPreparer:
             req.local_file_path = local_file.path
 
         dist = _get_prepared_distribution(
-            req, self.req_tracker, self.finder, self.build_isolation,
+            req,
+            self.build_tracker,
+            self.finder,
+            self.build_isolation,
+            self.check_build_deps,
         )
         return dist
 
-    def save_linked_requirement(self, req):
-        # type: (InstallRequirement) -> None
+    def save_linked_requirement(self, req: InstallRequirement) -> None:
         assert self.download_dir is not None
         assert req.link is not None
         link = req.link
@@ -584,8 +648,9 @@ class RequirementPreparer:
 
         if link.is_existing_dir():
             logger.debug(
-                'Not copying link to destination directory '
-                'since it is a directory: %s', link,
+                "Not copying link to destination directory "
+                "since it is a directory: %s",
+                link,
             )
             return
         if req.local_file_path is None:
@@ -596,31 +661,35 @@ class RequirementPreparer:
         if not os.path.exists(download_location):
             shutil.copy(req.local_file_path, download_location)
             download_path = display_path(download_location)
-            logger.info('Saved %s', download_path)
+            logger.info("Saved %s", download_path)
 
     def prepare_editable_requirement(
         self,
-        req,  # type: InstallRequirement
-    ):
-        # type: (...) -> Distribution
-        """Prepare an editable requirement
-        """
+        req: InstallRequirement,
+    ) -> BaseDistribution:
+        """Prepare an editable requirement."""
         assert req.editable, "cannot prepare a non-editable req as editable"
 
-        logger.info('Obtaining %s', req)
+        logger.info("Obtaining %s", req)
 
         with indent_log():
             if self.require_hashes:
                 raise InstallationError(
-                    'The editable requirement {} cannot be installed when '
-                    'requiring hashes, because there is no single file to '
-                    'hash.'.format(req)
+                    "The editable requirement {} cannot be installed when "
+                    "requiring hashes, because there is no single file to "
+                    "hash.".format(req)
                 )
             req.ensure_has_source_dir(self.src_dir)
             req.update_editable()
+            assert req.source_dir
+            req.download_info = direct_url_for_editable(req.unpacked_source_directory)
 
             dist = _get_prepared_distribution(
-                req, self.req_tracker, self.finder, self.build_isolation,
+                req,
+                self.build_tracker,
+                self.finder,
+                self.build_isolation,
+                self.check_build_deps,
             )
 
             req.check_if_exists(self.use_user_site)
@@ -629,27 +698,24 @@ class RequirementPreparer:
 
     def prepare_installed_requirement(
         self,
-        req,  # type: InstallRequirement
-        skip_reason  # type: str
-    ):
-        # type: (...) -> Distribution
-        """Prepare an already-installed requirement
-        """
+        req: InstallRequirement,
+        skip_reason: str,
+    ) -> BaseDistribution:
+        """Prepare an already-installed requirement."""
         assert req.satisfied_by, "req should have been satisfied but isn't"
         assert skip_reason is not None, (
             "did not get skip reason skipped but req.satisfied_by "
             "is set to {}".format(req.satisfied_by)
         )
         logger.info(
-            'Requirement %s: %s (%s)',
-            skip_reason, req, req.satisfied_by.version
+            "Requirement %s: %s (%s)", skip_reason, req, req.satisfied_by.version
         )
         with indent_log():
             if self.require_hashes:
                 logger.debug(
-                    'Since it is already installed, we are trusting this '
-                    'package without checking its hash. To ensure a '
-                    'completely repeatable environment, install into an '
-                    'empty virtualenv.'
+                    "Since it is already installed, we are trusting this "
+                    "package without checking its hash. To ensure a "
+                    "completely repeatable environment, install into an "
+                    "empty virtualenv."
                 )
-            return InstalledDistribution(req).get_pkg_resources_distribution()
+            return InstalledDistribution(req).get_metadata_distribution()

venv/Lib/site-packages/pip/_internal/pyproject.py

@@ -1,3 +1,4 @@
+import importlib.util
 import os
 from collections import namedtuple
 from typing import Any, List, Optional
@@ -5,34 +6,29 @@ from typing import Any, List, Optional
 from pip._vendor import tomli
 from pip._vendor.packaging.requirements import InvalidRequirement, Requirement
 
-from pip._internal.exceptions import InstallationError
+from pip._internal.exceptions import (
+    InstallationError,
+    InvalidPyProjectBuildRequires,
+    MissingPyProjectBuildRequires,
+)
 
 
-def _is_list_of_str(obj):
-    # type: (Any) -> bool
-    return (
-        isinstance(obj, list) and
-        all(isinstance(item, str) for item in obj)
-    )
+def _is_list_of_str(obj: Any) -> bool:
+    return isinstance(obj, list) and all(isinstance(item, str) for item in obj)
 
 
-def make_pyproject_path(unpacked_source_directory):
-    # type: (str) -> str
-    return os.path.join(unpacked_source_directory, 'pyproject.toml')
+def make_pyproject_path(unpacked_source_directory: str) -> str:
+    return os.path.join(unpacked_source_directory, "pyproject.toml")
 
 
-BuildSystemDetails = namedtuple('BuildSystemDetails', [
-    'requires', 'backend', 'check', 'backend_path'
-])
+BuildSystemDetails = namedtuple(
+    "BuildSystemDetails", ["requires", "backend", "check", "backend_path"]
+)
 
 
 def load_pyproject_toml(
-    use_pep517,  # type: Optional[bool]
-    pyproject_toml,  # type: str
-    setup_py,  # type: str
-    req_name  # type: str
-):
-    # type: (...) -> Optional[BuildSystemDetails]
+    use_pep517: Optional[bool], pyproject_toml: str, setup_py: str, req_name: str
+) -> Optional[BuildSystemDetails]:
     """Load the pyproject.toml file.
 
     Parameters:
@@ -57,9 +53,15 @@ def load_pyproject_toml(
     has_pyproject = os.path.isfile(pyproject_toml)
     has_setup = os.path.isfile(setup_py)
 
+    if not has_pyproject and not has_setup:
+        raise InstallationError(
+            f"{req_name} does not appear to be a Python project: "
+            f"neither 'setup.py' nor 'pyproject.toml' found."
+        )
+
     if has_pyproject:
         with open(pyproject_toml, encoding="utf-8") as f:
-            pp_toml = tomli.load(f)
+            pp_toml = tomli.loads(f.read())
         build_system = pp_toml.get("build-system")
     else:
         build_system = None
@@ -82,17 +84,26 @@ def load_pyproject_toml(
             raise InstallationError(
                 "Disabling PEP 517 processing is invalid: "
                 "project specifies a build backend of {} "
-                "in pyproject.toml".format(
-                    build_system["build-backend"]
-                )
+                "in pyproject.toml".format(build_system["build-backend"])
             )
         use_pep517 = True
 
     # If we haven't worked out whether to use PEP 517 yet,
     # and the user hasn't explicitly stated a preference,
-    # we do so if the project has a pyproject.toml file.
+    # we do so if the project has a pyproject.toml file
+    # or if we cannot import setuptools or wheels.
+
+    # We fallback to PEP 517 when without setuptools or without the wheel package,
+    # so setuptools can be installed as a default build backend.
+    # For more info see:
+    # https://discuss.python.org/t/pip-without-setuptools-could-the-experience-be-improved/11810/9
+    # https://github.com/pypa/pip/issues/8559
     elif use_pep517 is None:
-        use_pep517 = has_pyproject
+        use_pep517 = (
+            has_pyproject
+            or not importlib.util.find_spec("setuptools")
+            or not importlib.util.find_spec("wheel")
+        )
 
     # At this point, we know whether we're going to use PEP 517.
     assert use_pep517 is not None
@@ -124,52 +135,37 @@ def load_pyproject_toml(
 
     # Ensure that the build-system section in pyproject.toml conforms
     # to PEP 518.
-    error_template = (
-        "{package} has a pyproject.toml file that does not comply "
-        "with PEP 518: {reason}"
-    )
 
     # Specifying the build-system table but not the requires key is invalid
     if "requires" not in build_system:
-        raise InstallationError(
-            error_template.format(package=req_name, reason=(
-                "it has a 'build-system' table but not "
-                "'build-system.requires' which is mandatory in the table"
-            ))
-        )
+        raise MissingPyProjectBuildRequires(package=req_name)
 
     # Error out if requires is not a list of strings
     requires = build_system["requires"]
     if not _is_list_of_str(requires):
-        raise InstallationError(error_template.format(
+        raise InvalidPyProjectBuildRequires(
             package=req_name,
-            reason="'build-system.requires' is not a list of strings.",
-        ))
+            reason="It is not a list of strings.",
+        )
 
     # Each requirement must be valid as per PEP 508
     for requirement in requires:
         try:
             Requirement(requirement)
-        except InvalidRequirement:
-            raise InstallationError(
-                error_template.format(
-                    package=req_name,
-                    reason=(
-                        "'build-system.requires' contains an invalid "
-                        "requirement: {!r}".format(requirement)
-                    ),
-                )
-            )
+        except InvalidRequirement as error:
+            raise InvalidPyProjectBuildRequires(
+                package=req_name,
+                reason=f"It contains an invalid requirement: {requirement!r}",
+            ) from error
 
     backend = build_system.get("build-backend")
     backend_path = build_system.get("backend-path", [])
-    check = []  # type: List[str]
+    check: List[str] = []
     if backend is None:
         # If the user didn't specify a backend, we assume they want to use
         # the setuptools backend. But we can't be sure they have included
-        # a version of setuptools which supplies the backend, or wheel
-        # (which is needed by the backend) in their requirements. So we
-        # make a note to check that those requirements are present once
+        # a version of setuptools which supplies the backend. So we
+        # make a note to check that this requirement is present once
         # we have set up the environment.
         # This is quite a lot of work to check for a very specific case. But
         # the problem is, that case is potentially quite common - projects that
@@ -178,6 +174,6 @@ def load_pyproject_toml(
         # tools themselves. The original PEP 518 code had a similar check (but
         # implemented in a different way).
         backend = "setuptools.build_meta:__legacy__"
-        check = ["setuptools>=40.8.0", "wheel"]
+        check = ["setuptools>=40.8.0"]
 
     return BuildSystemDetails(requires, backend, check, backend_path)

venv/Lib/site-packages/pip/_internal/req/__init__.py

@@ -1,6 +1,6 @@
 import collections
 import logging
-from typing import Iterator, List, Optional, Sequence, Tuple
+from typing import Generator, List, Optional, Sequence, Tuple
 
 from pip._internal.utils.logging import indent_log
 
@@ -9,8 +9,10 @@ from .req_install import InstallRequirement
 from .req_set import RequirementSet
 
 __all__ = [
-    "RequirementSet", "InstallRequirement",
-    "parse_requirements", "install_given_reqs",
+    "RequirementSet",
+    "InstallRequirement",
+    "parse_requirements",
+    "install_given_reqs",
 ]
 
 logger = logging.getLogger(__name__)
@@ -26,7 +28,7 @@ class InstallationResult:
 
 def _validate_requirements(
     requirements: List[InstallRequirement],
-) -> Iterator[Tuple[str, InstallRequirement]]:
+) -> Generator[Tuple[str, InstallRequirement], None, None]:
     for req in requirements:
         assert req.name, f"invalid to-be-installed requirement: {req}"
         yield req.name, req
@@ -34,7 +36,6 @@ def _validate_requirements(
 
 def install_given_reqs(
     requirements: List[InstallRequirement],
-    install_options: List[str],
     global_options: Sequence[str],
     root: Optional[str],
     home: Optional[str],
@@ -52,8 +53,8 @@ def install_given_reqs(
 
     if to_install:
         logger.info(
-            'Installing collected packages: %s',
-            ', '.join(to_install.keys()),
+            "Installing collected packages: %s",
+            ", ".join(to_install.keys()),
         )
 
     installed = []
@@ -61,17 +62,14 @@ def install_given_reqs(
     with indent_log():
         for req_name, requirement in to_install.items():
             if requirement.should_reinstall:
-                logger.info('Attempting uninstall: %s', req_name)
+                logger.info("Attempting uninstall: %s", req_name)
                 with indent_log():
-                    uninstalled_pathset = requirement.uninstall(
-                        auto_confirm=True
-                    )
+                    uninstalled_pathset = requirement.uninstall(auto_confirm=True)
             else:
                 uninstalled_pathset = None
 
             try:
                 requirement.install(
-                    install_options,
                     global_options,
                     root=root,
                     home=home,

venv/Lib/site-packages/pip/_internal/req/constructors.py

@@ -11,28 +11,28 @@ InstallRequirement.
 import logging
 import os
 import re
-from typing import Any, Dict, Optional, Set, Tuple, Union
+from typing import Dict, List, Optional, Set, Tuple, Union
 
 from pip._vendor.packaging.markers import Marker
 from pip._vendor.packaging.requirements import InvalidRequirement, Requirement
 from pip._vendor.packaging.specifiers import Specifier
-from pip._vendor.pkg_resources import RequirementParseError, parse_requirements
 
 from pip._internal.exceptions import InstallationError
 from pip._internal.models.index import PyPI, TestPyPI
 from pip._internal.models.link import Link
 from pip._internal.models.wheel import Wheel
-from pip._internal.pyproject import make_pyproject_path
 from pip._internal.req.req_file import ParsedRequirement
 from pip._internal.req.req_install import InstallRequirement
 from pip._internal.utils.filetypes import is_archive_file
 from pip._internal.utils.misc import is_installable_dir
+from pip._internal.utils.packaging import get_requirement
 from pip._internal.utils.urls import path_to_url
 from pip._internal.vcs import is_url, vcs
 
 __all__ = [
-    "install_req_from_editable", "install_req_from_line",
-    "parse_editable"
+    "install_req_from_editable",
+    "install_req_from_line",
+    "parse_editable",
 ]
 
 logger = logging.getLogger(__name__)
@@ -40,7 +40,7 @@ operators = Specifier._operators.keys()
 
 
 def _strip_extras(path: str) -> Tuple[str, Optional[str]]:
-    m = re.match(r'^(.+)(\[[^\]]+\])$', path)
+    m = re.match(r"^(.+)(\[[^\]]+\])$", path)
     extras = None
     if m:
         path_no_extras = m.group(1)
@@ -54,7 +54,7 @@ def _strip_extras(path: str) -> Tuple[str, Optional[str]]:
 def convert_extras(extras: Optional[str]) -> Set[str]:
     if not extras:
         return set()
-    return Requirement("placeholder" + extras.lower()).extras
+    return get_requirement("placeholder" + extras.lower()).extras
 
 
 def parse_editable(editable_req: str) -> Tuple[Optional[str], str, Set[str]]:
@@ -74,39 +74,23 @@ def parse_editable(editable_req: str) -> Tuple[Optional[str], str, Set[str]]:
     url_no_extras, extras = _strip_extras(url)
 
     if os.path.isdir(url_no_extras):
-        setup_py = os.path.join(url_no_extras, 'setup.py')
-        setup_cfg = os.path.join(url_no_extras, 'setup.cfg')
-        if not os.path.exists(setup_py) and not os.path.exists(setup_cfg):
-            msg = (
-                'File "setup.py" or "setup.cfg" not found. Directory cannot be '
-                'installed in editable mode: {}'
-                .format(os.path.abspath(url_no_extras))
-            )
-            pyproject_path = make_pyproject_path(url_no_extras)
-            if os.path.isfile(pyproject_path):
-                msg += (
-                    '\n(A "pyproject.toml" file was found, but editable '
-                    'mode currently requires a setuptools-based build.)'
-                )
-            raise InstallationError(msg)
-
         # Treating it as code that has already been checked out
         url_no_extras = path_to_url(url_no_extras)
 
-    if url_no_extras.lower().startswith('file:'):
+    if url_no_extras.lower().startswith("file:"):
         package_name = Link(url_no_extras).egg_fragment
         if extras:
             return (
                 package_name,
                 url_no_extras,
-                Requirement("placeholder" + extras.lower()).extras,
+                get_requirement("placeholder" + extras.lower()).extras,
             )
         else:
             return package_name, url_no_extras, set()
 
     for version_control in vcs:
-        if url.lower().startswith(f'{version_control}:'):
-            url = f'{version_control}+{url}'
+        if url.lower().startswith(f"{version_control}:"):
+            url = f"{version_control}+{url}"
             break
 
     link = Link(url)
@@ -114,9 +98,9 @@ def parse_editable(editable_req: str) -> Tuple[Optional[str], str, Set[str]]:
     if not link.is_vcs:
         backends = ", ".join(vcs.all_schemes)
         raise InstallationError(
-            f'{editable_req} is not a valid editable requirement. '
-            f'It should either be a path to a local project or a VCS URL '
-            f'(beginning with {backends}).'
+            f"{editable_req} is not a valid editable requirement. "
+            f"It should either be a path to a local project or a VCS URL "
+            f"(beginning with {backends})."
         )
 
     package_name = link.egg_fragment
@@ -128,43 +112,66 @@ def parse_editable(editable_req: str) -> Tuple[Optional[str], str, Set[str]]:
     return package_name, url, set()
 
 
+def check_first_requirement_in_file(filename: str) -> None:
+    """Check if file is parsable as a requirements file.
+
+    This is heavily based on ``pkg_resources.parse_requirements``, but
+    simplified to just check the first meaningful line.
+
+    :raises InvalidRequirement: If the first meaningful line cannot be parsed
+        as an requirement.
+    """
+    with open(filename, encoding="utf-8", errors="ignore") as f:
+        # Create a steppable iterator, so we can handle \-continuations.
+        lines = (
+            line
+            for line in (line.strip() for line in f)
+            if line and not line.startswith("#")  # Skip blank lines/comments.
+        )
+
+        for line in lines:
+            # Drop comments -- a hash without a space may be in a URL.
+            if " #" in line:
+                line = line[: line.find(" #")]
+            # If there is a line continuation, drop it, and append the next line.
+            if line.endswith("\\"):
+                line = line[:-2].strip() + next(lines, "")
+            Requirement(line)
+            return
+
+
 def deduce_helpful_msg(req: str) -> str:
     """Returns helpful msg in case requirements file does not exist,
     or cannot be parsed.
 
     :params req: Requirements file path
     """
-    msg = ""
-    if os.path.exists(req):
-        msg = " The path does exist. "
-        # Try to parse and check if it is a requirements file.
-        try:
-            with open(req) as fp:
-                # parse first line only
-                next(parse_requirements(fp.read()))
-                msg += (
-                    "The argument you provided "
-                    "({}) appears to be a"
-                    " requirements file. If that is the"
-                    " case, use the '-r' flag to install"
-                    " the packages specified within it."
-                ).format(req)
-        except RequirementParseError:
-            logger.debug(
-                "Cannot parse '%s' as requirements file", req, exc_info=True
-            )
+    if not os.path.exists(req):
+        return f" File '{req}' does not exist."
+    msg = " The path does exist. "
+    # Try to parse and check if it is a requirements file.
+    try:
+        check_first_requirement_in_file(req)
+    except InvalidRequirement:
+        logger.debug("Cannot parse '%s' as requirements file", req)
     else:
-        msg += f" File '{req}' does not exist."
+        msg += (
+            f"The argument you provided "
+            f"({req}) appears to be a"
+            f" requirements file. If that is the"
+            f" case, use the '-r' flag to install"
+            f" the packages specified within it."
+        )
     return msg
 
 
 class RequirementParts:
     def __init__(
-            self,
-            requirement: Optional[Requirement],
-            link: Optional[Link],
-            markers: Optional[Marker],
-            extras: Set[str],
+        self,
+        requirement: Optional[Requirement],
+        link: Optional[Link],
+        markers: Optional[Marker],
+        extras: Set[str],
     ):
         self.requirement = requirement
         self.link = link
@@ -194,13 +201,16 @@ def parse_req_from_editable(editable_req: str) -> RequirementParts:
 def install_req_from_editable(
     editable_req: str,
     comes_from: Optional[Union[InstallRequirement, str]] = None,
+    *,
     use_pep517: Optional[bool] = None,
     isolated: bool = False,
-    options: Optional[Dict[str, Any]] = None,
+    global_options: Optional[List[str]] = None,
+    hash_options: Optional[Dict[str, List[str]]] = None,
     constraint: bool = False,
     user_supplied: bool = False,
+    permit_editable_wheels: bool = False,
+    config_settings: Optional[Dict[str, Union[str, List[str]]]] = None,
 ) -> InstallRequirement:
-
     parts = parse_req_from_editable(editable_req)
 
     return InstallRequirement(
@@ -208,13 +218,14 @@ def install_req_from_editable(
         comes_from=comes_from,
         user_supplied=user_supplied,
         editable=True,
+        permit_editable_wheels=permit_editable_wheels,
         link=parts.link,
         constraint=constraint,
         use_pep517=use_pep517,
         isolated=isolated,
-        install_options=options.get("install_options", []) if options else [],
-        global_options=options.get("global_options", []) if options else [],
-        hash_options=options.get("hashes", {}) if options else {},
+        global_options=global_options,
+        hash_options=hash_options,
+        config_settings=config_settings,
         extras=parts.extras,
     )
 
@@ -250,6 +261,8 @@ def _get_url_from_path(path: str, name: str) -> Optional[str]:
     if _looks_like_path(name) and os.path.isdir(path):
         if is_installable_dir(path):
             return path_to_url(path)
+        # TODO: The is_installable_dir test here might not be necessary
+        #       now that it is done in load_pyproject_toml too.
         raise InstallationError(
             f"Directory {name!r} is not installable. Neither 'setup.py' "
             "nor 'pyproject.toml' found."
@@ -258,24 +271,23 @@ def _get_url_from_path(path: str, name: str) -> Optional[str]:
         return None
     if os.path.isfile(path):
         return path_to_url(path)
-    urlreq_parts = name.split('@', 1)
+    urlreq_parts = name.split("@", 1)
     if len(urlreq_parts) >= 2 and not _looks_like_path(urlreq_parts[0]):
         # If the path contains '@' and the part before it does not look
         # like a path, try to treat it as a PEP 440 URL req instead.
         return None
     logger.warning(
-        'Requirement %r looks like a filename, but the '
-        'file does not exist',
-        name
+        "Requirement %r looks like a filename, but the file does not exist",
+        name,
     )
     return path_to_url(path)
 
 
 def parse_req_from_line(name: str, line_source: Optional[str]) -> RequirementParts:
     if is_url(name):
-        marker_sep = '; '
+        marker_sep = "; "
     else:
-        marker_sep = ';'
+        marker_sep = ";"
     if marker_sep in name:
         name, markers_as_string = name.split(marker_sep, 1)
         markers_as_string = markers_as_string.strip()
@@ -302,9 +314,8 @@ def parse_req_from_line(name: str, line_source: Optional[str]) -> RequirementPar
     # it's a local file, dir, or url
     if link:
         # Handle relative file URLs
-        if link.scheme == 'file' and re.search(r'\.\./', link.url):
-            link = Link(
-                path_to_url(os.path.normpath(os.path.abspath(link.path))))
+        if link.scheme == "file" and re.search(r"\.\./", link.url):
+            link = Link(path_to_url(os.path.normpath(os.path.abspath(link.path))))
         # wheel file
         if link.is_wheel:
             wheel = Wheel(link.filename)  # can raise InvalidWheelFilename
@@ -323,25 +334,24 @@ def parse_req_from_line(name: str, line_source: Optional[str]) -> RequirementPar
     def with_source(text: str) -> str:
         if not line_source:
             return text
-        return f'{text} (from {line_source})'
+        return f"{text} (from {line_source})"
 
     def _parse_req_string(req_as_string: str) -> Requirement:
         try:
-            req = Requirement(req_as_string)
+            req = get_requirement(req_as_string)
         except InvalidRequirement:
             if os.path.sep in req_as_string:
                 add_msg = "It looks like a path."
                 add_msg += deduce_helpful_msg(req_as_string)
-            elif ('=' in req_as_string and
-                  not any(op in req_as_string for op in operators)):
+            elif "=" in req_as_string and not any(
+                op in req_as_string for op in operators
+            ):
                 add_msg = "= is not a valid operator. Did you mean == ?"
             else:
-                add_msg = ''
-            msg = with_source(
-                f'Invalid requirement: {req_as_string!r}'
-            )
+                add_msg = ""
+            msg = with_source(f"Invalid requirement: {req_as_string!r}")
             if add_msg:
-                msg += f'\nHint: {add_msg}'
+                msg += f"\nHint: {add_msg}"
             raise InstallationError(msg)
         else:
             # Deprecate extras after specifiers: "name>=1.0[extras]"
@@ -350,7 +360,7 @@ def parse_req_from_line(name: str, line_source: Optional[str]) -> RequirementPar
             # RequirementParts
             for spec in req.specifier:
                 spec_str = str(spec)
-                if spec_str.endswith(']'):
+                if spec_str.endswith("]"):
                     msg = f"Extras after version '{spec_str}'."
                     raise InstallationError(msg)
         return req
@@ -366,12 +376,15 @@ def parse_req_from_line(name: str, line_source: Optional[str]) -> RequirementPar
 def install_req_from_line(
     name: str,
     comes_from: Optional[Union[str, InstallRequirement]] = None,
+    *,
     use_pep517: Optional[bool] = None,
     isolated: bool = False,
-    options: Optional[Dict[str, Any]] = None,
+    global_options: Optional[List[str]] = None,
+    hash_options: Optional[Dict[str, List[str]]] = None,
     constraint: bool = False,
     line_source: Optional[str] = None,
     user_supplied: bool = False,
+    config_settings: Optional[Dict[str, Union[str, List[str]]]] = None,
 ) -> InstallRequirement:
     """Creates an InstallRequirement from a name, which might be a
     requirement, directory containing 'setup.py', filename, or URL.
@@ -382,11 +395,15 @@ def install_req_from_line(
     parts = parse_req_from_line(name, line_source)
 
     return InstallRequirement(
-        parts.requirement, comes_from, link=parts.link, markers=parts.markers,
-        use_pep517=use_pep517, isolated=isolated,
-        install_options=options.get("install_options", []) if options else [],
-        global_options=options.get("global_options", []) if options else [],
-        hash_options=options.get("hashes", {}) if options else {},
+        parts.requirement,
+        comes_from,
+        link=parts.link,
+        markers=parts.markers,
+        use_pep517=use_pep517,
+        isolated=isolated,
+        global_options=global_options,
+        hash_options=hash_options,
+        config_settings=config_settings,
         constraint=constraint,
         extras=parts.extras,
         user_supplied=user_supplied,
@@ -401,7 +418,7 @@ def install_req_from_req_string(
     user_supplied: bool = False,
 ) -> InstallRequirement:
     try:
-        req = Requirement(req_string)
+        req = get_requirement(req_string)
     except InvalidRequirement:
         raise InstallationError(f"Invalid requirement: '{req_string}'")
 
@@ -409,8 +426,12 @@ def install_req_from_req_string(
         PyPI.file_storage_domain,
         TestPyPI.file_storage_domain,
     ]
-    if (req.url and comes_from and comes_from.link and
-            comes_from.link.netloc in domains_not_allowed):
+    if (
+        req.url
+        and comes_from
+        and comes_from.link
+        and comes_from.link.netloc in domains_not_allowed
+    ):
         # Explicitly disallow pypi packages that depend on external urls
         raise InstallationError(
             "Packages installed from PyPI cannot depend on packages "
@@ -432,6 +453,7 @@ def install_req_from_parsed_requirement(
     isolated: bool = False,
     use_pep517: Optional[bool] = None,
     user_supplied: bool = False,
+    config_settings: Optional[Dict[str, Union[str, List[str]]]] = None,
 ) -> InstallRequirement:
     if parsed_req.is_editable:
         req = install_req_from_editable(
@@ -441,6 +463,7 @@ def install_req_from_parsed_requirement(
             constraint=parsed_req.constraint,
             isolated=isolated,
             user_supplied=user_supplied,
+            config_settings=config_settings,
         )
 
     else:
@@ -449,10 +472,18 @@ def install_req_from_parsed_requirement(
             comes_from=parsed_req.comes_from,
             use_pep517=use_pep517,
             isolated=isolated,
-            options=parsed_req.options,
+            global_options=(
+                parsed_req.options.get("global_options", [])
+                if parsed_req.options
+                else []
+            ),
+            hash_options=(
+                parsed_req.options.get("hashes", {}) if parsed_req.options else {}
+            ),
             constraint=parsed_req.constraint,
             line_source=parsed_req.line_source,
             user_supplied=user_supplied,
+            config_settings=config_settings,
         )
     return req
 
@@ -468,7 +499,8 @@ def install_req_from_link_and_ireq(
         markers=ireq.markers,
         use_pep517=ireq.use_pep517,
         isolated=ireq.isolated,
-        install_options=ireq.install_options,
         global_options=ireq.global_options,
         hash_options=ireq.hash_options,
+        config_settings=ireq.config_settings,
+        user_supplied=ireq.user_supplied,
     )

venv/Lib/site-packages/pip/_internal/req/req_file.py

@@ -2,13 +2,24 @@
 Requirements file parsing
 """
 
+import logging
 import optparse
 import os
 import re
 import shlex
 import urllib.parse
 from optparse import Values
-from typing import TYPE_CHECKING, Any, Callable, Dict, Iterator, List, Optional, Tuple
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Callable,
+    Dict,
+    Generator,
+    Iterable,
+    List,
+    Optional,
+    Tuple,
+)
 
 from pip._internal.cli import cmdoptions
 from pip._internal.exceptions import InstallationError, RequirementsFileParseError
@@ -25,20 +36,20 @@ if TYPE_CHECKING:
 
     from pip._internal.index.package_finder import PackageFinder
 
-__all__ = ['parse_requirements']
+__all__ = ["parse_requirements"]
 
-ReqFileLines = Iterator[Tuple[int, str]]
+ReqFileLines = Iterable[Tuple[int, str]]
 
 LineParser = Callable[[str], Tuple[str, Values]]
 
-SCHEME_RE = re.compile(r'^(http|https|file):', re.I)
-COMMENT_RE = re.compile(r'(^|\s+)#.*$')
+SCHEME_RE = re.compile(r"^(http|https|file):", re.I)
+COMMENT_RE = re.compile(r"(^|\s+)#.*$")
 
 # Matches environment variable-style values in '${MY_VARIABLE_1}' with the
 # variable name consisting of only uppercase letters, digits or the '_'
 # (underscore). This follows the POSIX standard defined in IEEE Std 1003.1,
 # 2013 Edition.
-ENV_VAR_RE = re.compile(r'(?P<var>\$\{(?P<name>[A-Z0-9_]+)\})')
+ENV_VAR_RE = re.compile(r"(?P<var>\$\{(?P<name>[A-Z0-9_]+)\})")
 
 SUPPORTED_OPTIONS: List[Callable[..., optparse.Option]] = [
     cmdoptions.index_url,
@@ -59,14 +70,16 @@ SUPPORTED_OPTIONS: List[Callable[..., optparse.Option]] = [
 
 # options to be passed to requirements
 SUPPORTED_OPTIONS_REQ: List[Callable[..., optparse.Option]] = [
-    cmdoptions.install_options,
     cmdoptions.global_options,
     cmdoptions.hash,
+    cmdoptions.config_settings,
 ]
 
 # the 'dest' string values
 SUPPORTED_OPTIONS_REQ_DEST = [str(o().dest) for o in SUPPORTED_OPTIONS_REQ]
 
+logger = logging.getLogger(__name__)
+
 
 class ParsedRequirement:
     def __init__(
@@ -119,7 +132,7 @@ def parse_requirements(
     finder: Optional["PackageFinder"] = None,
     options: Optional[optparse.Values] = None,
     constraint: bool = False,
-) -> Iterator[ParsedRequirement]:
+) -> Generator[ParsedRequirement, None, None]:
     """Parse a requirements file and yield ParsedRequirement instances.
 
     :param filename:    Path or url of requirements file.
@@ -134,10 +147,7 @@ def parse_requirements(
 
     for parsed_line in parser.parse(filename, constraint):
         parsed_req = handle_line(
-            parsed_line,
-            options=options,
-            finder=finder,
-            session=session
+            parsed_line, options=options, finder=finder, session=session
         )
         if parsed_req is not None:
             yield parsed_req
@@ -159,10 +169,11 @@ def handle_requirement_line(
     line: ParsedLine,
     options: Optional[optparse.Values] = None,
 ) -> ParsedRequirement:
-
     # preserve for the nested code path
-    line_comes_from = '{} {} (line {})'.format(
-        '-c' if line.constraint else '-r', line.filename, line.lineno,
+    line_comes_from = "{} {} (line {})".format(
+        "-c" if line.constraint else "-r",
+        line.filename,
+        line.lineno,
     )
 
     assert line.is_requirement
@@ -177,17 +188,13 @@ def handle_requirement_line(
             constraint=line.constraint,
         )
     else:
-        if options:
-            # Disable wheels if the user has specified build options
-            cmdoptions.check_install_build_global(options, line.opts)
-
         # get the options that apply to requirements
         req_options = {}
         for dest in SUPPORTED_OPTIONS_REQ_DEST:
             if dest in line.opts.__dict__ and line.opts.__dict__[dest]:
                 req_options[dest] = line.opts.__dict__[dest]
 
-        line_source = f'line {line.lineno} of {line.filename}'
+        line_source = f"line {line.lineno} of {line.filename}"
         return ParsedRequirement(
             requirement=line.requirement,
             is_editable=line.is_editable,
@@ -206,6 +213,12 @@ def handle_option_line(
     options: Optional[optparse.Values] = None,
     session: Optional[PipSession] = None,
 ) -> None:
+    if opts.hashes:
+        logger.warning(
+            "%s line %s has --hash but no requirement, and will be ignored.",
+            filename,
+            lineno,
+        )
 
     if options:
         # percolate options upward
@@ -213,19 +226,20 @@ def handle_option_line(
             options.require_hashes = opts.require_hashes
         if opts.features_enabled:
             options.features_enabled.extend(
-                f for f in opts.features_enabled
-                if f not in options.features_enabled
+                f for f in opts.features_enabled if f not in options.features_enabled
             )
 
     # set finder options
     if finder:
         find_links = finder.find_links
         index_urls = finder.index_urls
-        if opts.index_url:
-            index_urls = [opts.index_url]
+        no_index = finder.search_scope.no_index
         if opts.no_index is True:
+            no_index = True
             index_urls = []
-        if opts.extra_index_urls:
+        if opts.index_url and not no_index:
+            index_urls = [opts.index_url]
+        if opts.extra_index_urls and not no_index:
             index_urls.extend(opts.extra_index_urls)
         if opts.find_links:
             # FIXME: it would be nice to keep track of the source
@@ -245,6 +259,7 @@ def handle_option_line(
         search_scope = SearchScope(
             find_links=find_links,
             index_urls=index_urls,
+            no_index=no_index,
         )
         finder.search_scope = search_scope
 
@@ -256,7 +271,7 @@ def handle_option_line(
 
         if session:
             for host in opts.trusted_hosts or []:
-                source = f'line {lineno} of {filename}'
+                source = f"line {lineno} of {filename}"
                 session.add_trusted_host(host, source=source)
 
 
@@ -313,18 +328,18 @@ class RequirementsFileParser:
         self._session = session
         self._line_parser = line_parser
 
-    def parse(self, filename: str, constraint: bool) -> Iterator[ParsedLine]:
-        """Parse a given file, yielding parsed lines.
-        """
+    def parse(
+        self, filename: str, constraint: bool
+    ) -> Generator[ParsedLine, None, None]:
+        """Parse a given file, yielding parsed lines."""
         yield from self._parse_and_recurse(filename, constraint)
 
     def _parse_and_recurse(
         self, filename: str, constraint: bool
-    ) -> Iterator[ParsedLine]:
+    ) -> Generator[ParsedLine, None, None]:
         for line in self._parse_file(filename, constraint):
-            if (
-                not line.is_requirement and
-                (line.opts.requirements or line.opts.constraints)
+            if not line.is_requirement and (
+                line.opts.requirements or line.opts.constraints
             ):
                 # parse a nested requirements file
                 if line.opts.requirements:
@@ -342,14 +357,17 @@ class RequirementsFileParser:
                 elif not SCHEME_RE.search(req_path):
                     # do a join so relative paths work
                     req_path = os.path.join(
-                        os.path.dirname(filename), req_path,
+                        os.path.dirname(filename),
+                        req_path,
                     )
 
                 yield from self._parse_and_recurse(req_path, nested_constraint)
             else:
                 yield line
 
-    def _parse_file(self, filename: str, constraint: bool) -> Iterator[ParsedLine]:
+    def _parse_file(
+        self, filename: str, constraint: bool
+    ) -> Generator[ParsedLine, None, None]:
         _, content = get_file_content(filename, self._session)
 
         lines_enum = preprocess(content)
@@ -359,7 +377,7 @@ class RequirementsFileParser:
                 args_str, opts = self._line_parser(line)
             except OptionParsingError as e:
                 # add offending line
-                msg = f'Invalid requirement: {line}\n{e.msg}'
+                msg = f"Invalid requirement: {line}\n{e.msg}"
                 raise RequirementsFileParseError(msg)
 
             yield ParsedLine(
@@ -383,7 +401,12 @@ def get_line_parser(finder: Optional["PackageFinder"]) -> LineParser:
 
         args_str, options_str = break_args_options(line)
 
-        opts, _ = parser.parse_args(shlex.split(options_str), defaults)
+        try:
+            options = shlex.split(options_str)
+        except ValueError as e:
+            raise OptionParsingError(f"Could not split options: {options_str}") from e
+
+        opts, _ = parser.parse_args(options, defaults)
 
         return args_str, opts
 
@@ -395,16 +418,16 @@ def break_args_options(line: str) -> Tuple[str, str]:
     (and then optparse) the options, not the args.  args can contain markers
     which are corrupted by shlex.
     """
-    tokens = line.split(' ')
+    tokens = line.split(" ")
     args = []
     options = tokens[:]
     for token in tokens:
-        if token.startswith('-') or token.startswith('--'):
+        if token.startswith("-") or token.startswith("--"):
             break
         else:
             args.append(token)
             options.pop(0)
-    return ' '.join(args), ' '.join(options)
+    return " ".join(args), " ".join(options)
 
 
 class OptionParsingError(Exception):
@@ -427,6 +450,7 @@ def build_parser() -> optparse.OptionParser:
     # that in our own exception.
     def parser_exit(self: Any, msg: str) -> "NoReturn":
         raise OptionParsingError(msg)
+
     # NOTE: mypy disallows assigning to a method
     #       https://github.com/python/mypy/issues/2427
     parser.exit = parser_exit  # type: ignore
@@ -441,26 +465,26 @@ def join_lines(lines_enum: ReqFileLines) -> ReqFileLines:
     primary_line_number = None
     new_line: List[str] = []
     for line_number, line in lines_enum:
-        if not line.endswith('\\') or COMMENT_RE.match(line):
+        if not line.endswith("\\") or COMMENT_RE.match(line):
             if COMMENT_RE.match(line):
                 # this ensures comments are always matched later
-                line = ' ' + line
+                line = " " + line
             if new_line:
                 new_line.append(line)
                 assert primary_line_number is not None
-                yield primary_line_number, ''.join(new_line)
+                yield primary_line_number, "".join(new_line)
                 new_line = []
             else:
                 yield line_number, line
         else:
             if not new_line:
                 primary_line_number = line_number
-            new_line.append(line.strip('\\'))
+            new_line.append(line.strip("\\"))
 
     # last line contains \
     if new_line:
         assert primary_line_number is not None
-        yield primary_line_number, ''.join(new_line)
+        yield primary_line_number, "".join(new_line)
 
     # TODO: handle space after '\'.
 
@@ -470,7 +494,7 @@ def ignore_comments(lines_enum: ReqFileLines) -> ReqFileLines:
     Strips comments and filter empty lines.
     """
     for line_number, line in lines_enum:
-        line = COMMENT_RE.sub('', line)
+        line = COMMENT_RE.sub("", line)
         line = line.strip()
         if line:
             yield line_number, line
@@ -514,15 +538,15 @@ def get_file_content(url: str, session: PipSession) -> Tuple[str, str]:
     scheme = get_url_scheme(url)
 
     # Pip has special support for file:// URLs (LocalFSAdapter).
-    if scheme in ['http', 'https', 'file']:
+    if scheme in ["http", "https", "file"]:
         resp = session.get(url)
         raise_for_status(resp)
         return resp.url, resp.text
 
     # Assume this is a bare path.
     try:
-        with open(url, 'rb') as f:
+        with open(url, "rb") as f:
             content = auto_decode(f.read())
     except OSError as exc:
-        raise InstallationError(f'Could not open requirements file: {exc}')
+        raise InstallationError(f"Could not open requirements file: {exc}")
     return url, content

venv/Lib/site-packages/pip/_internal/req/req_install.py

@@ -1,55 +1,59 @@
 # The following comment should be removed at some point in the future.
 # mypy: strict-optional=False
 
+import functools
 import logging
 import os
 import shutil
 import sys
 import uuid
 import zipfile
-from typing import Any, Dict, Iterable, List, Optional, Sequence, Union
+from optparse import Values
+from typing import Any, Collection, Dict, Iterable, List, Optional, Sequence, Union
 
-from pip._vendor import pkg_resources, six
 from pip._vendor.packaging.markers import Marker
 from pip._vendor.packaging.requirements import Requirement
 from pip._vendor.packaging.specifiers import SpecifierSet
 from pip._vendor.packaging.utils import canonicalize_name
 from pip._vendor.packaging.version import Version
 from pip._vendor.packaging.version import parse as parse_version
-from pip._vendor.pep517.wrappers import Pep517HookCaller
-from pip._vendor.pkg_resources import Distribution
+from pip._vendor.pyproject_hooks import BuildBackendHookCaller
 
 from pip._internal.build_env import BuildEnvironment, NoOpBuildEnvironment
 from pip._internal.exceptions import InstallationError
 from pip._internal.locations import get_scheme
+from pip._internal.metadata import (
+    BaseDistribution,
+    get_default_environment,
+    get_directory_distribution,
+    get_wheel_distribution,
+)
+from pip._internal.metadata.base import FilesystemWheel
+from pip._internal.models.direct_url import DirectUrl
 from pip._internal.models.link import Link
 from pip._internal.operations.build.metadata import generate_metadata
+from pip._internal.operations.build.metadata_editable import generate_editable_metadata
 from pip._internal.operations.build.metadata_legacy import (
     generate_metadata as generate_metadata_legacy,
 )
 from pip._internal.operations.install.editable_legacy import (
     install_editable as install_editable_legacy,
 )
-from pip._internal.operations.install.legacy import LegacyInstallFailure
-from pip._internal.operations.install.legacy import install as install_legacy
 from pip._internal.operations.install.wheel import install_wheel
 from pip._internal.pyproject import load_pyproject_toml, make_pyproject_path
 from pip._internal.req.req_uninstall import UninstallPathSet
 from pip._internal.utils.deprecation import deprecated
-from pip._internal.utils.direct_url_helpers import direct_url_from_link
 from pip._internal.utils.hashes import Hashes
-from pip._internal.utils.logging import indent_log
 from pip._internal.utils.misc import (
+    ConfiguredBuildBackendHookCaller,
     ask_path_exists,
     backup_dir,
     display_path,
-    dist_in_site_packages,
-    dist_in_usersite,
-    get_distribution,
     hide_url,
     redact_auth_from_url,
 )
-from pip._internal.utils.packaging import get_metadata
+from pip._internal.utils.packaging import safe_extra
+from pip._internal.utils.subprocess import runner_with_spinner_message
 from pip._internal.utils.temp_dir import TempDirectory, tempdir_kinds
 from pip._internal.utils.virtualenv import running_under_virtualenv
 from pip._internal.vcs import vcs
@@ -57,32 +61,6 @@ from pip._internal.vcs import vcs
 logger = logging.getLogger(__name__)
 
 
-def _get_dist(metadata_directory: str) -> Distribution:
-    """Return a pkg_resources.Distribution for the provided
-    metadata directory.
-    """
-    dist_dir = metadata_directory.rstrip(os.sep)
-
-    # Build a PathMetadata object, from path to metadata. :wink:
-    base_dir, dist_dir_name = os.path.split(dist_dir)
-    metadata = pkg_resources.PathMetadata(base_dir, dist_dir)
-
-    # Determine the correct Distribution object type.
-    if dist_dir.endswith(".egg-info"):
-        dist_cls = pkg_resources.Distribution
-        dist_name = os.path.splitext(dist_dir_name)[0]
-    else:
-        assert dist_dir.endswith(".dist-info")
-        dist_cls = pkg_resources.DistInfoDistribution
-        dist_name = os.path.splitext(dist_dir_name)[0].split("-")[0]
-
-    return dist_cls(
-        base_dir,
-        project_name=dist_name,
-        metadata=metadata,
-    )
-
-
 class InstallRequirement:
     """
     Represents something that may be installed later on, may have information
@@ -99,19 +77,21 @@ class InstallRequirement:
         markers: Optional[Marker] = None,
         use_pep517: Optional[bool] = None,
         isolated: bool = False,
-        install_options: Optional[List[str]] = None,
+        *,
         global_options: Optional[List[str]] = None,
         hash_options: Optional[Dict[str, List[str]]] = None,
+        config_settings: Optional[Dict[str, Union[str, List[str]]]] = None,
         constraint: bool = False,
-        extras: Iterable[str] = (),
+        extras: Collection[str] = (),
         user_supplied: bool = False,
+        permit_editable_wheels: bool = False,
     ) -> None:
         assert req is None or isinstance(req, Requirement), req
         self.req = req
         self.comes_from = comes_from
         self.constraint = constraint
         self.editable = editable
-        self.legacy_install_reason: Optional[int] = None
+        self.permit_editable_wheels = permit_editable_wheels
 
         # source_dir is the local directory where the linked requirement is
         # located, or unpacked. In case unpacking is needed, creating and
@@ -122,15 +102,21 @@ class InstallRequirement:
         if self.editable:
             assert link
             if link.is_file:
-                self.source_dir = os.path.normpath(
-                    os.path.abspath(link.file_path)
-                )
+                self.source_dir = os.path.normpath(os.path.abspath(link.file_path))
 
         if link is None and req and req.url:
             # PEP 508 URL requirement
             link = Link(req.url)
         self.link = self.original_link = link
-        self.original_link_is_in_wheel_cache = False
+
+        # When this InstallRequirement is a wheel obtained from the cache of locally
+        # built wheels, this is the source link corresponding to the cache entry, which
+        # was used to download and build the cached wheel.
+        self.cached_wheel_source_link: Optional[Link] = None
+
+        # Information about the location of the artifact that was downloaded . This
+        # property is guaranteed to be set in resolver results.
+        self.download_info: Optional[DirectUrl] = None
 
         # Path to any downloaded or already-existing package.
         self.local_file_path: Optional[str] = None
@@ -140,18 +126,15 @@ class InstallRequirement:
         if extras:
             self.extras = extras
         elif req:
-            self.extras = {
-                pkg_resources.safe_extra(extra) for extra in req.extras
-            }
+            self.extras = {safe_extra(extra) for extra in req.extras}
         else:
             self.extras = set()
         if markers is None and req:
             markers = req.marker
         self.markers = markers
 
-        # This holds the pkg_resources.Distribution object if this requirement
-        # is already available:
-        self.satisfied_by: Optional[Distribution] = None
+        # This holds the Distribution object if this requirement is already installed.
+        self.satisfied_by: Optional[BaseDistribution] = None
         # Whether the installation process should try to uninstall an existing
         # distribution before installing this requirement.
         self.should_reinstall = False
@@ -160,9 +143,9 @@ class InstallRequirement:
         # Set to True after successful installation
         self.install_succeeded: Optional[bool] = None
         # Supplied options
-        self.install_options = install_options if install_options else []
         self.global_options = global_options if global_options else []
         self.hash_options = hash_options if hash_options else {}
+        self.config_settings = config_settings
         # Set to True after successful preparation of this requirement
         self.prepared = False
         # User supplied requirement are explicitly requested for installation
@@ -186,7 +169,7 @@ class InstallRequirement:
         self.requirements_to_check: List[str] = []
 
         # The PEP 517 backend we should use to build the project
-        self.pep517_backend: Optional[Pep517HookCaller] = None
+        self.pep517_backend: Optional[BuildBackendHookCaller] = None
 
         # Are we using PEP 517 for this requirement?
         # After pyproject.toml has been loaded, the only valid values are True
@@ -202,36 +185,38 @@ class InstallRequirement:
         if self.req:
             s = str(self.req)
             if self.link:
-                s += ' from {}'.format(redact_auth_from_url(self.link.url))
+                s += " from {}".format(redact_auth_from_url(self.link.url))
         elif self.link:
             s = redact_auth_from_url(self.link.url)
         else:
-            s = '<InstallRequirement>'
+            s = "<InstallRequirement>"
         if self.satisfied_by is not None:
-            s += ' in {}'.format(display_path(self.satisfied_by.location))
+            if self.satisfied_by.location is not None:
+                location = display_path(self.satisfied_by.location)
+            else:
+                location = "<memory>"
+            s += f" in {location}"
         if self.comes_from:
             if isinstance(self.comes_from, str):
                 comes_from: Optional[str] = self.comes_from
             else:
                 comes_from = self.comes_from.from_path()
             if comes_from:
-                s += f' (from {comes_from})'
+                s += f" (from {comes_from})"
         return s
 
     def __repr__(self) -> str:
-        return '<{} object: {} editable={!r}>'.format(
-            self.__class__.__name__, str(self), self.editable)
+        return "<{} object: {} editable={!r}>".format(
+            self.__class__.__name__, str(self), self.editable
+        )
 
     def format_debug(self) -> str:
-        """An un-tested helper for getting state, for debugging.
-        """
+        """An un-tested helper for getting state, for debugging."""
         attributes = vars(self)
         names = sorted(attributes)
 
-        state = (
-            "{}={!r}".format(attr, attributes[attr]) for attr in sorted(names)
-        )
-        return '<{name} object: {{{state}}}>'.format(
+        state = ("{}={!r}".format(attr, attributes[attr]) for attr in sorted(names))
+        return "<{name} object: {{{state}}}>".format(
             name=self.__class__.__name__,
             state=", ".join(state),
         )
@@ -241,7 +226,19 @@ class InstallRequirement:
     def name(self) -> Optional[str]:
         if self.req is None:
             return None
-        return pkg_resources.safe_name(self.req.name)
+        return self.req.name
+
+    @functools.lru_cache()  # use cached_property in python 3.8+
+    def supports_pyproject_editable(self) -> bool:
+        if not self.use_pep517:
+            return False
+        assert self.pep517_backend
+        with self.build_env:
+            runner = runner_with_spinner_message(
+                "Checking if build backend supports build_editable"
+            )
+            with self.pep517_backend.subprocess_runner(runner):
+                return "build_editable" in self.pep517_backend._supported_features()
 
     @property
     def specifier(self) -> SpecifierSet:
@@ -254,18 +251,17 @@ class InstallRequirement:
         For example, some-package==1.2 is pinned; some-package>1.2 is not.
         """
         specifiers = self.specifier
-        return (len(specifiers) == 1 and
-                next(iter(specifiers)).operator in {'==', '==='})
+        return len(specifiers) == 1 and next(iter(specifiers)).operator in {"==", "==="}
 
     def match_markers(self, extras_requested: Optional[Iterable[str]] = None) -> bool:
         if not extras_requested:
             # Provide an extra to safely evaluate the markers
             # without matching any extra
-            extras_requested = ('',)
+            extras_requested = ("",)
         if self.markers is not None:
             return any(
-                self.markers.evaluate({'extra': extra})
-                for extra in extras_requested)
+                self.markers.evaluate({"extra": extra}) for extra in extras_requested
+            )
         else:
             return True
 
@@ -295,14 +291,18 @@ class InstallRequirement:
 
         """
         good_hashes = self.hash_options.copy()
-        link = self.link if trust_internet else self.original_link
+        if trust_internet:
+            link = self.link
+        elif self.original_link and self.user_supplied:
+            link = self.original_link
+        else:
+            link = None
         if link and link.hash:
             good_hashes.setdefault(link.hash_name, []).append(link.hash)
         return Hashes(good_hashes)
 
     def from_path(self) -> Optional[str]:
-        """Format a nice indicator to show where this "comes from"
-        """
+        """Format a nice indicator to show where this "comes from" """
         if self.req is None:
             return None
         s = str(self.req)
@@ -312,7 +312,7 @@ class InstallRequirement:
             else:
                 comes_from = self.comes_from.from_path()
             if comes_from:
-                s += '->' + comes_from
+                s += "->" + comes_from
         return s
 
     def ensure_build_location(
@@ -345,7 +345,7 @@ class InstallRequirement:
         # FIXME: Is there a better place to create the build_dir? (hg and bzr
         # need this)
         if not os.path.exists(build_dir):
-            logger.debug('Creating directory %s', build_dir)
+            logger.debug("Creating directory %s", build_dir)
             os.makedirs(build_dir)
         actual_build_dir = os.path.join(build_dir, dir_name)
         # `None` indicates that we respect the globally-configured deletion
@@ -359,8 +359,7 @@ class InstallRequirement:
         ).path
 
     def _set_requirement(self) -> None:
-        """Set requirement after generating metadata.
-        """
+        """Set requirement after generating metadata."""
         assert self.req is None
         assert self.metadata is not None
         assert self.source_dir is not None
@@ -372,11 +371,13 @@ class InstallRequirement:
             op = "==="
 
         self.req = Requirement(
-            "".join([
-                self.metadata["Name"],
-                op,
-                self.metadata["Version"],
-            ])
+            "".join(
+                [
+                    self.metadata["Name"],
+                    op,
+                    self.metadata["Version"],
+                ]
+            )
         )
 
     def warn_on_mismatching_name(self) -> None:
@@ -387,10 +388,12 @@ class InstallRequirement:
 
         # If we're here, there's a mismatch. Log a warning about it.
         logger.warning(
-            'Generating metadata for package %s '
-            'produced metadata for project name %s. Fix your '
-            '#egg=%s fragments.',
-            self.name, metadata_name, self.name
+            "Generating metadata for package %s "
+            "produced metadata for project name %s. Fix your "
+            "#egg=%s fragments.",
+            self.name,
+            metadata_name,
+            self.name,
         )
         self.req = Requirement(metadata_name)
 
@@ -401,30 +404,24 @@ class InstallRequirement:
         """
         if self.req is None:
             return
-        existing_dist = get_distribution(self.req.name)
+        existing_dist = get_default_environment().get_distribution(self.req.name)
         if not existing_dist:
             return
 
-        # pkg_resouces may contain a different copy of packaging.version from
-        # pip in if the downstream distributor does a poor job debundling pip.
-        # We avoid existing_dist.parsed_version and let SpecifierSet.contains
-        # parses the version instead.
-        existing_version = existing_dist.version
-        version_compatible = (
-            existing_version is not None and
-            self.req.specifier.contains(existing_version, prereleases=True)
+        version_compatible = self.req.specifier.contains(
+            existing_dist.version,
+            prereleases=True,
         )
         if not version_compatible:
             self.satisfied_by = None
             if use_user_site:
-                if dist_in_usersite(existing_dist):
+                if existing_dist.in_usersite:
                     self.should_reinstall = True
-                elif (running_under_virtualenv() and
-                        dist_in_site_packages(existing_dist)):
+                elif running_under_virtualenv() and existing_dist.in_site_packages:
                     raise InstallationError(
-                        "Will not install to the user site because it will "
-                        "lack sys.path precedence to {} in {}".format(
-                            existing_dist.project_name, existing_dist.location)
+                        f"Will not install to the user site because it will "
+                        f"lack sys.path precedence to {existing_dist.raw_name} "
+                        f"in {existing_dist.location}"
                     )
             else:
                 self.should_reinstall = True
@@ -444,20 +441,33 @@ class InstallRequirement:
             return False
         return self.link.is_wheel
 
+    @property
+    def is_wheel_from_cache(self) -> bool:
+        # When True, it means that this InstallRequirement is a local wheel file in the
+        # cache of locally built wheels.
+        return self.cached_wheel_source_link is not None
+
     # Things valid for sdists
     @property
     def unpacked_source_directory(self) -> str:
         return os.path.join(
-            self.source_dir,
-            self.link and self.link.subdirectory_fragment or '')
+            self.source_dir, self.link and self.link.subdirectory_fragment or ""
+        )
 
     @property
     def setup_py_path(self) -> str:
         assert self.source_dir, f"No source dir for {self}"
-        setup_py = os.path.join(self.unpacked_source_directory, 'setup.py')
+        setup_py = os.path.join(self.unpacked_source_directory, "setup.py")
 
         return setup_py
 
+    @property
+    def setup_cfg_path(self) -> str:
+        assert self.source_dir, f"No source dir for {self}"
+        setup_cfg = os.path.join(self.unpacked_source_directory, "setup.cfg")
+
+        return setup_cfg
+
     @property
     def pyproject_toml_path(self) -> str:
         assert self.source_dir, f"No source dir for {self}"
@@ -472,13 +482,19 @@ class InstallRequirement:
         follow the PEP 517 or legacy (setup.py) code path.
         """
         pyproject_toml_data = load_pyproject_toml(
-            self.use_pep517,
-            self.pyproject_toml_path,
-            self.setup_py_path,
-            str(self)
+            self.use_pep517, self.pyproject_toml_path, self.setup_py_path, str(self)
         )
 
         if pyproject_toml_data is None:
+            if self.config_settings:
+                deprecated(
+                    reason=f"Config settings are ignored for project {self}.",
+                    replacement=(
+                        "to use --use-pep517 or add a "
+                        "pyproject.toml file to the project"
+                    ),
+                    gone_in="23.3",
+                )
             self.use_pep517 = False
             return
 
@@ -486,46 +502,69 @@ class InstallRequirement:
         requires, backend, check, backend_path = pyproject_toml_data
         self.requirements_to_check = check
         self.pyproject_requires = requires
-        self.pep517_backend = Pep517HookCaller(
-            self.unpacked_source_directory, backend, backend_path=backend_path,
+        self.pep517_backend = ConfiguredBuildBackendHookCaller(
+            self,
+            self.unpacked_source_directory,
+            backend,
+            backend_path=backend_path,
         )
 
-    def _generate_metadata(self) -> str:
-        """Invokes metadata generator functions, with the required arguments.
+    def isolated_editable_sanity_check(self) -> None:
+        """Check that an editable requirement if valid for use with PEP 517/518.
+
+        This verifies that an editable that has a pyproject.toml either supports PEP 660
+        or as a setup.py or a setup.cfg
         """
-        if not self.use_pep517:
-            assert self.unpacked_source_directory
-
-            if not os.path.exists(self.setup_py_path):
-                raise InstallationError(
-                    f'File "setup.py" not found for legacy project {self}.'
-                )
-
-            return generate_metadata_legacy(
-                build_env=self.build_env,
-                setup_py_path=self.setup_py_path,
-                source_dir=self.unpacked_source_directory,
-                isolated=self.isolated,
-                details=self.name or f"from {self.link}"
+        if (
+            self.editable
+            and self.use_pep517
+            and not self.supports_pyproject_editable()
+            and not os.path.isfile(self.setup_py_path)
+            and not os.path.isfile(self.setup_cfg_path)
+        ):
+            raise InstallationError(
+                f"Project {self} has a 'pyproject.toml' and its build "
+                f"backend is missing the 'build_editable' hook. Since it does not "
+                f"have a 'setup.py' nor a 'setup.cfg', "
+                f"it cannot be installed in editable mode. "
+                f"Consider using a build backend that supports PEP 660."
             )
 
-        assert self.pep517_backend is not None
-
-        return generate_metadata(
-            build_env=self.build_env,
-            backend=self.pep517_backend,
-        )
-
     def prepare_metadata(self) -> None:
         """Ensure that project metadata is available.
 
-        Under PEP 517, call the backend hook to prepare the metadata.
+        Under PEP 517 and PEP 660, call the backend hook to prepare the metadata.
         Under legacy processing, call setup.py egg-info.
         """
         assert self.source_dir
+        details = self.name or f"from {self.link}"
 
-        with indent_log():
-            self.metadata_directory = self._generate_metadata()
+        if self.use_pep517:
+            assert self.pep517_backend is not None
+            if (
+                self.editable
+                and self.permit_editable_wheels
+                and self.supports_pyproject_editable()
+            ):
+                self.metadata_directory = generate_editable_metadata(
+                    build_env=self.build_env,
+                    backend=self.pep517_backend,
+                    details=details,
+                )
+            else:
+                self.metadata_directory = generate_metadata(
+                    build_env=self.build_env,
+                    backend=self.pep517_backend,
+                    details=details,
+                )
+        else:
+            self.metadata_directory = generate_metadata_legacy(
+                build_env=self.build_env,
+                setup_py_path=self.setup_py_path,
+                source_dir=self.unpacked_source_directory,
+                isolated=self.isolated,
+                details=details,
+            )
 
         # Act on the newly generated metadata, based on the name and version.
         if not self.name:
@@ -537,26 +576,35 @@ class InstallRequirement:
 
     @property
     def metadata(self) -> Any:
-        if not hasattr(self, '_metadata'):
-            self._metadata = get_metadata(self.get_dist())
+        if not hasattr(self, "_metadata"):
+            self._metadata = self.get_dist().metadata
 
         return self._metadata
 
-    def get_dist(self) -> Distribution:
-        return _get_dist(self.metadata_directory)
+    def get_dist(self) -> BaseDistribution:
+        if self.metadata_directory:
+            return get_directory_distribution(self.metadata_directory)
+        elif self.local_file_path and self.is_wheel:
+            return get_wheel_distribution(
+                FilesystemWheel(self.local_file_path), canonicalize_name(self.name)
+            )
+        raise AssertionError(
+            f"InstallRequirement {self} has no metadata directory and no wheel: "
+            f"can't make a distribution."
+        )
 
     def assert_source_matches_version(self) -> None:
         assert self.source_dir
-        version = self.metadata['version']
+        version = self.metadata["version"]
         if self.req.specifier and version not in self.req.specifier:
             logger.warning(
-                'Requested %s, but installing version %s',
+                "Requested %s, but installing version %s",
                 self,
                 version,
             )
         else:
             logger.debug(
-                'Source in %s has version %s, which satisfies requirement %s',
+                "Source in %s has version %s, which satisfies requirement %s",
                 display_path(self.source_dir),
                 version,
                 self,
@@ -589,14 +637,13 @@ class InstallRequirement:
     def update_editable(self) -> None:
         if not self.link:
             logger.debug(
-                "Cannot update repository at %s; repository location is "
-                "unknown",
+                "Cannot update repository at %s; repository location is unknown",
                 self.source_dir,
             )
             return
         assert self.editable
         assert self.source_dir
-        if self.link.scheme == 'file':
+        if self.link.scheme == "file":
             # Static paths don't get updated
             return
         vcs_backend = vcs.get_backend_for_scheme(self.link.scheme)
@@ -604,7 +651,7 @@ class InstallRequirement:
         # So here, if it's neither a path nor a valid VCS URL, it's a bug.
         assert vcs_backend, f"Unsupported VCS URL {self.link.url}"
         hidden_url = hide_url(self.link.url)
-        vcs_backend.obtain(self.source_dir, url=hidden_url)
+        vcs_backend.obtain(self.source_dir, url=hidden_url, verbosity=0)
 
     # Top-level Actions
     def uninstall(
@@ -623,29 +670,28 @@ class InstallRequirement:
 
         """
         assert self.req
-        dist = get_distribution(self.req.name)
+        dist = get_default_environment().get_distribution(self.req.name)
         if not dist:
             logger.warning("Skipping %s as it is not installed.", self.name)
             return None
-        logger.info('Found existing installation: %s', dist)
+        logger.info("Found existing installation: %s", dist)
 
         uninstalled_pathset = UninstallPathSet.from_dist(dist)
         uninstalled_pathset.remove(auto_confirm, verbose)
         return uninstalled_pathset
 
     def _get_archive_name(self, path: str, parentdir: str, rootdir: str) -> str:
-
         def _clean_zip_name(name: str, prefix: str) -> str:
-            assert name.startswith(prefix + os.path.sep), (
-                f"name {name!r} doesn't start with prefix {prefix!r}"
-            )
-            name = name[len(prefix) + 1:]
-            name = name.replace(os.path.sep, '/')
+            assert name.startswith(
+                prefix + os.path.sep
+            ), f"name {name!r} doesn't start with prefix {prefix!r}"
+            name = name[len(prefix) + 1 :]
+            name = name.replace(os.path.sep, "/")
             return name
 
         path = os.path.join(parentdir, path)
         name = _clean_zip_name(path, rootdir)
-        return self.name + '/' + name
+        return self.name + "/" + name
 
     def archive(self, build_dir: Optional[str]) -> None:
         """Saves archive to provided build_dir.
@@ -657,68 +703,72 @@ class InstallRequirement:
             return
 
         create_archive = True
-        archive_name = '{}-{}.zip'.format(self.name, self.metadata["version"])
+        archive_name = "{}-{}.zip".format(self.name, self.metadata["version"])
         archive_path = os.path.join(build_dir, archive_name)
 
         if os.path.exists(archive_path):
             response = ask_path_exists(
-                'The file {} exists. (i)gnore, (w)ipe, '
-                '(b)ackup, (a)bort '.format(
-                    display_path(archive_path)),
-                ('i', 'w', 'b', 'a'))
-            if response == 'i':
+                "The file {} exists. (i)gnore, (w)ipe, "
+                "(b)ackup, (a)bort ".format(display_path(archive_path)),
+                ("i", "w", "b", "a"),
+            )
+            if response == "i":
                 create_archive = False
-            elif response == 'w':
-                logger.warning('Deleting %s', display_path(archive_path))
+            elif response == "w":
+                logger.warning("Deleting %s", display_path(archive_path))
                 os.remove(archive_path)
-            elif response == 'b':
+            elif response == "b":
                 dest_file = backup_dir(archive_path)
                 logger.warning(
-                    'Backing up %s to %s',
+                    "Backing up %s to %s",
                     display_path(archive_path),
                     display_path(dest_file),
                 )
                 shutil.move(archive_path, dest_file)
-            elif response == 'a':
+            elif response == "a":
                 sys.exit(-1)
 
         if not create_archive:
             return
 
         zip_output = zipfile.ZipFile(
-            archive_path, 'w', zipfile.ZIP_DEFLATED, allowZip64=True,
+            archive_path,
+            "w",
+            zipfile.ZIP_DEFLATED,
+            allowZip64=True,
         )
         with zip_output:
-            dir = os.path.normcase(
-                os.path.abspath(self.unpacked_source_directory)
-            )
+            dir = os.path.normcase(os.path.abspath(self.unpacked_source_directory))
             for dirpath, dirnames, filenames in os.walk(dir):
                 for dirname in dirnames:
                     dir_arcname = self._get_archive_name(
-                        dirname, parentdir=dirpath, rootdir=dir,
+                        dirname,
+                        parentdir=dirpath,
+                        rootdir=dir,
                     )
-                    zipdir = zipfile.ZipInfo(dir_arcname + '/')
+                    zipdir = zipfile.ZipInfo(dir_arcname + "/")
                     zipdir.external_attr = 0x1ED << 16  # 0o755
-                    zip_output.writestr(zipdir, '')
+                    zip_output.writestr(zipdir, "")
                 for filename in filenames:
                     file_arcname = self._get_archive_name(
-                        filename, parentdir=dirpath, rootdir=dir,
+                        filename,
+                        parentdir=dirpath,
+                        rootdir=dir,
                     )
                     filename = os.path.join(dirpath, filename)
                     zip_output.write(filename, file_arcname)
 
-        logger.info('Saved %s', display_path(archive_path))
+        logger.info("Saved %s", display_path(archive_path))
 
     def install(
         self,
-        install_options: List[str],
         global_options: Optional[Sequence[str]] = None,
         root: Optional[str] = None,
         home: Optional[str] = None,
         prefix: Optional[str] = None,
         warn_script_location: bool = True,
         use_user_site: bool = False,
-        pycompile: bool = True
+        pycompile: bool = True,
     ) -> None:
         scheme = get_scheme(
             self.name,
@@ -729,11 +779,9 @@ class InstallRequirement:
             prefix=prefix,
         )
 
-        global_options = global_options if global_options is not None else []
-        if self.editable:
+        if self.editable and not self.is_wheel:
             install_editable_legacy(
-                install_options,
-                global_options,
+                global_options=global_options if global_options is not None else [],
                 prefix=prefix,
                 home=home,
                 use_user_site=use_user_site,
@@ -746,79 +794,23 @@ class InstallRequirement:
             self.install_succeeded = True
             return
 
-        if self.is_wheel:
-            assert self.local_file_path
-            direct_url = None
-            if self.original_link:
-                direct_url = direct_url_from_link(
-                    self.original_link,
-                    self.source_dir,
-                    self.original_link_is_in_wheel_cache,
-                )
-            install_wheel(
-                self.name,
-                self.local_file_path,
-                scheme=scheme,
-                req_description=str(self.req),
-                pycompile=pycompile,
-                warn_script_location=warn_script_location,
-                direct_url=direct_url,
-                requested=self.user_supplied,
-            )
-            self.install_succeeded = True
-            return
+        assert self.is_wheel
+        assert self.local_file_path
 
-        # TODO: Why don't we do this for editable installs?
-
-        # Extend the list of global and install options passed on to
-        # the setup.py call with the ones from the requirements file.
-        # Options specified in requirements file override those
-        # specified on the command line, since the last option given
-        # to setup.py is the one that is used.
-        global_options = list(global_options) + self.global_options
-        install_options = list(install_options) + self.install_options
-
-        try:
-            success = install_legacy(
-                install_options=install_options,
-                global_options=global_options,
-                root=root,
-                home=home,
-                prefix=prefix,
-                use_user_site=use_user_site,
-                pycompile=pycompile,
-                scheme=scheme,
-                setup_py_path=self.setup_py_path,
-                isolated=self.isolated,
-                req_name=self.name,
-                build_env=self.build_env,
-                unpacked_source_directory=self.unpacked_source_directory,
-                req_description=str(self.req),
-            )
-        except LegacyInstallFailure as exc:
-            self.install_succeeded = False
-            six.reraise(*exc.parent)
-        except Exception:
-            self.install_succeeded = True
-            raise
-
-        self.install_succeeded = success
-
-        if success and self.legacy_install_reason == 8368:
-            deprecated(
-                reason=(
-                    "{} was installed using the legacy 'setup.py install' "
-                    "method, because a wheel could not be built for it.".
-                    format(self.name)
-                ),
-                replacement="to fix the wheel build issue reported above",
-                gone_in=None,
-                issue=8368,
-            )
+        install_wheel(
+            self.name,
+            self.local_file_path,
+            scheme=scheme,
+            req_description=str(self.req),
+            pycompile=pycompile,
+            warn_script_location=warn_script_location,
+            direct_url=self.download_info if self.original_link else None,
+            requested=self.user_supplied,
+        )
+        self.install_succeeded = True
 
 
 def check_invalid_constraint_type(req: InstallRequirement) -> str:
-
     # Check for unsupported forms
     problem = ""
     if not req.name:
@@ -844,3 +836,32 @@ def check_invalid_constraint_type(req: InstallRequirement) -> str:
         )
 
     return problem
+
+
+def _has_option(options: Values, reqs: List[InstallRequirement], option: str) -> bool:
+    if getattr(options, option, None):
+        return True
+    for req in reqs:
+        if getattr(req, option, None):
+            return True
+    return False
+
+
+def check_legacy_setup_py_options(
+    options: Values,
+    reqs: List[InstallRequirement],
+) -> None:
+    has_build_options = _has_option(options, reqs, "build_options")
+    has_global_options = _has_option(options, reqs, "global_options")
+    if has_build_options or has_global_options:
+        deprecated(
+            reason="--build-option and --global-option are deprecated.",
+            issue=11859,
+            replacement="to use --config-settings",
+            gone_in="23.3",
+        )
+        logger.warning(
+            "Implying --no-binary=:all: due to the presence of "
+            "--build-option / --global-option. "
+        )
+        options.format_control.disallow_binaries()

venv/Lib/site-packages/pip/_internal/req/req_set.py

@@ -1,22 +1,17 @@
 import logging
 from collections import OrderedDict
-from typing import Dict, Iterable, List, Optional, Tuple
+from typing import Dict, List
 
 from pip._vendor.packaging.utils import canonicalize_name
 
-from pip._internal.exceptions import InstallationError
-from pip._internal.models.wheel import Wheel
 from pip._internal.req.req_install import InstallRequirement
-from pip._internal.utils import compatibility_tags
 
 logger = logging.getLogger(__name__)
 
 
 class RequirementSet:
-
     def __init__(self, check_supported_wheels: bool = True) -> None:
-        """Create a RequirementSet.
-        """
+        """Create a RequirementSet."""
 
         self.requirements: Dict[str, InstallRequirement] = OrderedDict()
         self.check_supported_wheels = check_supported_wheels
@@ -28,7 +23,7 @@ class RequirementSet:
             (req for req in self.requirements.values() if not req.comes_from),
             key=lambda req: canonicalize_name(req.name or ""),
         )
-        return ' '.join(str(req.req) for req in requirements)
+        return " ".join(str(req.req) for req in requirements)
 
     def __repr__(self) -> str:
         requirements = sorted(
@@ -36,11 +31,11 @@ class RequirementSet:
             key=lambda req: canonicalize_name(req.name or ""),
         )
 
-        format_string = '<{classname} object; {count} requirement(s): {reqs}>'
+        format_string = "<{classname} object; {count} requirement(s): {reqs}>"
         return format_string.format(
             classname=self.__class__.__name__,
             count=len(requirements),
-            reqs=', '.join(str(req.req) for req in requirements),
+            reqs=", ".join(str(req.req) for req in requirements),
         )
 
     def add_unnamed_requirement(self, install_req: InstallRequirement) -> None:
@@ -53,128 +48,12 @@ class RequirementSet:
         project_name = canonicalize_name(install_req.name)
         self.requirements[project_name] = install_req
 
-    def add_requirement(
-        self,
-        install_req: InstallRequirement,
-        parent_req_name: Optional[str] = None,
-        extras_requested: Optional[Iterable[str]] = None
-    ) -> Tuple[List[InstallRequirement], Optional[InstallRequirement]]:
-        """Add install_req as a requirement to install.
-
-        :param parent_req_name: The name of the requirement that needed this
-            added. The name is used because when multiple unnamed requirements
-            resolve to the same name, we could otherwise end up with dependency
-            links that point outside the Requirements set. parent_req must
-            already be added. Note that None implies that this is a user
-            supplied requirement, vs an inferred one.
-        :param extras_requested: an iterable of extras used to evaluate the
-            environment markers.
-        :return: Additional requirements to scan. That is either [] if
-            the requirement is not applicable, or [install_req] if the
-            requirement is applicable and has just been added.
-        """
-        # If the markers do not match, ignore this requirement.
-        if not install_req.match_markers(extras_requested):
-            logger.info(
-                "Ignoring %s: markers '%s' don't match your environment",
-                install_req.name, install_req.markers,
-            )
-            return [], None
-
-        # If the wheel is not supported, raise an error.
-        # Should check this after filtering out based on environment markers to
-        # allow specifying different wheels based on the environment/OS, in a
-        # single requirements file.
-        if install_req.link and install_req.link.is_wheel:
-            wheel = Wheel(install_req.link.filename)
-            tags = compatibility_tags.get_supported()
-            if (self.check_supported_wheels and not wheel.supported(tags)):
-                raise InstallationError(
-                    "{} is not a supported wheel on this platform.".format(
-                        wheel.filename)
-                )
-
-        # This next bit is really a sanity check.
-        assert not install_req.user_supplied or parent_req_name is None, (
-            "a user supplied req shouldn't have a parent"
-        )
-
-        # Unnamed requirements are scanned again and the requirement won't be
-        # added as a dependency until after scanning.
-        if not install_req.name:
-            self.add_unnamed_requirement(install_req)
-            return [install_req], None
-
-        try:
-            existing_req: Optional[InstallRequirement] = self.get_requirement(
-                install_req.name)
-        except KeyError:
-            existing_req = None
-
-        has_conflicting_requirement = (
-            parent_req_name is None and
-            existing_req and
-            not existing_req.constraint and
-            existing_req.extras == install_req.extras and
-            existing_req.req and
-            install_req.req and
-            existing_req.req.specifier != install_req.req.specifier
-        )
-        if has_conflicting_requirement:
-            raise InstallationError(
-                "Double requirement given: {} (already in {}, name={!r})"
-                .format(install_req, existing_req, install_req.name)
-            )
-
-        # When no existing requirement exists, add the requirement as a
-        # dependency and it will be scanned again after.
-        if not existing_req:
-            self.add_named_requirement(install_req)
-            # We'd want to rescan this requirement later
-            return [install_req], install_req
-
-        # Assume there's no need to scan, and that we've already
-        # encountered this for scanning.
-        if install_req.constraint or not existing_req.constraint:
-            return [], existing_req
-
-        does_not_satisfy_constraint = (
-            install_req.link and
-            not (
-                existing_req.link and
-                install_req.link.path == existing_req.link.path
-            )
-        )
-        if does_not_satisfy_constraint:
-            raise InstallationError(
-                "Could not satisfy constraints for '{}': "
-                "installation from path or url cannot be "
-                "constrained to a version".format(install_req.name)
-            )
-        # If we're now installing a constraint, mark the existing
-        # object for real installation.
-        existing_req.constraint = False
-        # If we're now installing a user supplied requirement,
-        # mark the existing object as such.
-        if install_req.user_supplied:
-            existing_req.user_supplied = True
-        existing_req.extras = tuple(sorted(
-            set(existing_req.extras) | set(install_req.extras)
-        ))
-        logger.debug(
-            "Setting %s extras to: %s",
-            existing_req, existing_req.extras,
-        )
-        # Return the existing requirement for addition to the parent and
-        # scanning again.
-        return [existing_req], existing_req
-
     def has_requirement(self, name: str) -> bool:
         project_name = canonicalize_name(name)
 
         return (
-            project_name in self.requirements and
-            not self.requirements[project_name].constraint
+            project_name in self.requirements
+            and not self.requirements[project_name].constraint
         )
 
     def get_requirement(self, name: str) -> InstallRequirement:
@@ -188,3 +67,16 @@ class RequirementSet:
     @property
     def all_requirements(self) -> List[InstallRequirement]:
         return self.unnamed_requirements + list(self.requirements.values())
+
+    @property
+    def requirements_to_install(self) -> List[InstallRequirement]:
+        """Return the list of requirements that need to be installed.
+
+        TODO remove this property together with the legacy resolver, since the new
+             resolver only returns requirements that need to be installed.
+        """
+        return [
+            install_req
+            for install_req in self.all_requirements
+            if not install_req.constraint and not install_req.satisfied_by
+        ]

venv/Lib/site-packages/pip/_internal/req/req_tracker.py

@@ -1,130 +0,0 @@
-import contextlib
-import hashlib
-import logging
-import os
-from types import TracebackType
-from typing import Dict, Iterator, Optional, Set, Type, Union
-
-from pip._internal.models.link import Link
-from pip._internal.req.req_install import InstallRequirement
-from pip._internal.utils.temp_dir import TempDirectory
-
-logger = logging.getLogger(__name__)
-
-
-@contextlib.contextmanager
-def update_env_context_manager(**changes: str) -> Iterator[None]:
-    target = os.environ
-
-    # Save values from the target and change them.
-    non_existent_marker = object()
-    saved_values: Dict[str, Union[object, str]] = {}
-    for name, new_value in changes.items():
-        try:
-            saved_values[name] = target[name]
-        except KeyError:
-            saved_values[name] = non_existent_marker
-        target[name] = new_value
-
-    try:
-        yield
-    finally:
-        # Restore original values in the target.
-        for name, original_value in saved_values.items():
-            if original_value is non_existent_marker:
-                del target[name]
-            else:
-                assert isinstance(original_value, str)  # for mypy
-                target[name] = original_value
-
-
-@contextlib.contextmanager
-def get_requirement_tracker() -> Iterator["RequirementTracker"]:
-    root = os.environ.get('PIP_REQ_TRACKER')
-    with contextlib.ExitStack() as ctx:
-        if root is None:
-            root = ctx.enter_context(
-                TempDirectory(kind='req-tracker')
-            ).path
-            ctx.enter_context(update_env_context_manager(PIP_REQ_TRACKER=root))
-            logger.debug("Initialized build tracking at %s", root)
-
-        with RequirementTracker(root) as tracker:
-            yield tracker
-
-
-class RequirementTracker:
-
-    def __init__(self, root: str) -> None:
-        self._root = root
-        self._entries: Set[InstallRequirement] = set()
-        logger.debug("Created build tracker: %s", self._root)
-
-    def __enter__(self) -> "RequirementTracker":
-        logger.debug("Entered build tracker: %s", self._root)
-        return self
-
-    def __exit__(
-        self,
-        exc_type: Optional[Type[BaseException]],
-        exc_val: Optional[BaseException],
-        exc_tb: Optional[TracebackType]
-    ) -> None:
-        self.cleanup()
-
-    def _entry_path(self, link: Link) -> str:
-        hashed = hashlib.sha224(link.url_without_fragment.encode()).hexdigest()
-        return os.path.join(self._root, hashed)
-
-    def add(self, req: InstallRequirement) -> None:
-        """Add an InstallRequirement to build tracking.
-        """
-
-        assert req.link
-        # Get the file to write information about this requirement.
-        entry_path = self._entry_path(req.link)
-
-        # Try reading from the file. If it exists and can be read from, a build
-        # is already in progress, so a LookupError is raised.
-        try:
-            with open(entry_path) as fp:
-                contents = fp.read()
-        except FileNotFoundError:
-            pass
-        else:
-            message = '{} is already being built: {}'.format(
-                req.link, contents)
-            raise LookupError(message)
-
-        # If we're here, req should really not be building already.
-        assert req not in self._entries
-
-        # Start tracking this requirement.
-        with open(entry_path, 'w', encoding="utf-8") as fp:
-            fp.write(str(req))
-        self._entries.add(req)
-
-        logger.debug('Added %s to build tracker %r', req, self._root)
-
-    def remove(self, req: InstallRequirement) -> None:
-        """Remove an InstallRequirement from build tracking.
-        """
-
-        assert req.link
-        # Delete the created file and the corresponding entries.
-        os.unlink(self._entry_path(req.link))
-        self._entries.remove(req)
-
-        logger.debug('Removed %s from build tracker %r', req, self._root)
-
-    def cleanup(self) -> None:
-        for req in set(self._entries):
-            self.remove(req)
-
-        logger.debug("Removed build tracker: %r", self._root)
-
-    @contextlib.contextmanager
-    def track(self, req: InstallRequirement) -> Iterator[None]:
-        self.add(req)
-        yield
-        self.remove(req)

venv/Lib/site-packages/pip/_internal/req/req_uninstall.py

@@ -1,67 +1,58 @@
-import csv
 import functools
 import os
 import sys
 import sysconfig
 from importlib.util import cache_from_source
-from typing import Any, Callable, Dict, Iterable, Iterator, List, Optional, Set, Tuple
-
-from pip._vendor import pkg_resources
-from pip._vendor.pkg_resources import Distribution
+from typing import Any, Callable, Dict, Generator, Iterable, List, Optional, Set, Tuple
 
 from pip._internal.exceptions import UninstallationError
 from pip._internal.locations import get_bin_prefix, get_bin_user
+from pip._internal.metadata import BaseDistribution
 from pip._internal.utils.compat import WINDOWS
+from pip._internal.utils.egg_link import egg_link_path_from_location
 from pip._internal.utils.logging import getLogger, indent_log
-from pip._internal.utils.misc import (
-    ask,
-    dist_in_usersite,
-    dist_is_local,
-    egg_link_path,
-    is_local,
-    normalize_path,
-    renames,
-    rmtree,
-)
+from pip._internal.utils.misc import ask, normalize_path, renames, rmtree
 from pip._internal.utils.temp_dir import AdjacentTempDirectory, TempDirectory
+from pip._internal.utils.virtualenv import running_under_virtualenv
 
 logger = getLogger(__name__)
 
 
-def _script_names(dist: Distribution, script_name: str, is_gui: bool) -> List[str]:
+def _script_names(
+    bin_dir: str, script_name: str, is_gui: bool
+) -> Generator[str, None, None]:
     """Create the fully qualified name of the files created by
     {console,gui}_scripts for the given ``dist``.
     Returns the list of file names
     """
-    if dist_in_usersite(dist):
-        bin_dir = get_bin_user()
-    else:
-        bin_dir = get_bin_prefix()
     exe_name = os.path.join(bin_dir, script_name)
-    paths_to_remove = [exe_name]
-    if WINDOWS:
-        paths_to_remove.append(exe_name + '.exe')
-        paths_to_remove.append(exe_name + '.exe.manifest')
-        if is_gui:
-            paths_to_remove.append(exe_name + '-script.pyw')
-        else:
-            paths_to_remove.append(exe_name + '-script.py')
-    return paths_to_remove
+    yield exe_name
+    if not WINDOWS:
+        return
+    yield f"{exe_name}.exe"
+    yield f"{exe_name}.exe.manifest"
+    if is_gui:
+        yield f"{exe_name}-script.pyw"
+    else:
+        yield f"{exe_name}-script.py"
 
 
-def _unique(fn: Callable[..., Iterator[Any]]) -> Callable[..., Iterator[Any]]:
+def _unique(
+    fn: Callable[..., Generator[Any, None, None]]
+) -> Callable[..., Generator[Any, None, None]]:
     @functools.wraps(fn)
-    def unique(*args: Any, **kw: Any) -> Iterator[Any]:
+    def unique(*args: Any, **kw: Any) -> Generator[Any, None, None]:
         seen: Set[Any] = set()
         for item in fn(*args, **kw):
             if item not in seen:
                 seen.add(item)
                 yield item
+
     return unique
 
 
 @_unique
-def uninstallation_paths(dist: Distribution) -> Iterator[str]:
+def uninstallation_paths(dist: BaseDistribution) -> Generator[str, None, None]:
     """
     Yield all the uninstallation paths for dist based on RECORD-without-.py[co]
 
@@ -75,30 +66,32 @@ def uninstallation_paths(dist: Distribution) -> Iterator[str]:
 
     https://packaging.python.org/specifications/recording-installed-packages/
     """
-    try:
-        r = csv.reader(dist.get_metadata_lines('RECORD'))
-    except FileNotFoundError as missing_record_exception:
-        msg = 'Cannot uninstall {dist}, RECORD file not found.'.format(dist=dist)
-        try:
-            installer = next(dist.get_metadata_lines('INSTALLER'))
-            if not installer or installer == 'pip':
-                raise ValueError()
-        except (OSError, StopIteration, ValueError):
-            dep = '{}=={}'.format(dist.project_name, dist.version)
-            msg += (" You might be able to recover from this via: "
-                    "'pip install --force-reinstall --no-deps {}'.".format(dep))
+    location = dist.location
+    assert location is not None, "not installed"
+
+    entries = dist.iter_declared_entries()
+    if entries is None:
+        msg = "Cannot uninstall {dist}, RECORD file not found.".format(dist=dist)
+        installer = dist.installer
+        if not installer or installer == "pip":
+            dep = "{}=={}".format(dist.raw_name, dist.version)
+            msg += (
+                " You might be able to recover from this via: "
+                "'pip install --force-reinstall --no-deps {}'.".format(dep)
+            )
         else:
-            msg += ' Hint: The package was installed by {}.'.format(installer)
-        raise UninstallationError(msg) from missing_record_exception
-    for row in r:
-        path = os.path.join(dist.location, row[0])
+            msg += " Hint: The package was installed by {}.".format(installer)
+        raise UninstallationError(msg)
+
+    for entry in entries:
+        path = os.path.join(location, entry)
         yield path
-        if path.endswith('.py'):
+        if path.endswith(".py"):
             dn, fn = os.path.split(path)
             base = fn[:-3]
-            path = os.path.join(dn, base + '.pyc')
+            path = os.path.join(dn, base + ".pyc")
             yield path
-            path = os.path.join(dn, base + '.pyo')
+            path = os.path.join(dn, base + ".pyo")
             yield path
 
 
@@ -112,8 +105,8 @@ def compact(paths: Iterable[str]) -> Set[str]:
     short_paths: Set[str] = set()
     for path in sorted(paths, key=len):
         should_skip = any(
-            path.startswith(shortpath.rstrip("*")) and
-            path[len(shortpath.rstrip("*").rstrip(sep))] == sep
+            path.startswith(shortpath.rstrip("*"))
+            and path[len(shortpath.rstrip("*").rstrip(sep))] == sep
             for shortpath in short_paths
         )
         if not should_skip:
@@ -136,18 +129,15 @@ def compress_for_rename(paths: Iterable[str]) -> Set[str]:
         return os.path.normcase(os.path.join(*a))
 
     for root in unchecked:
-        if any(os.path.normcase(root).startswith(w)
-               for w in wildcards):
+        if any(os.path.normcase(root).startswith(w) for w in wildcards):
             # This directory has already been handled.
             continue
 
         all_files: Set[str] = set()
         all_subdirs: Set[str] = set()
         for dirname, subdirs, files in os.walk(root):
-            all_subdirs.update(norm_join(root, dirname, d)
-                               for d in subdirs)
-            all_files.update(norm_join(root, dirname, f)
-                             for f in files)
+            all_subdirs.update(norm_join(root, dirname, d) for d in subdirs)
+            all_files.update(norm_join(root, dirname, f) for f in files)
         # If all the files we found are in our remaining set of files to
         # remove, then remove them from the latter set and add a wildcard
         # for the directory.
@@ -196,14 +186,14 @@ def compress_for_output_listing(paths: Iterable[str]) -> Tuple[Set[str], Set[str
                     continue
 
                 file_ = os.path.join(dirpath, fname)
-                if (os.path.isfile(file_) and
-                        os.path.normcase(file_) not in _normcased_files):
+                if (
+                    os.path.isfile(file_)
+                    and os.path.normcase(file_) not in _normcased_files
+                ):
                     # We are skipping this file. Add it to the set.
                     will_skip.add(file_)
 
-    will_remove = files | {
-        os.path.join(folder, "*") for folder in folders
-    }
+    will_remove = files | {os.path.join(folder, "*") for folder in folders}
 
     return will_remove, will_skip
 
@@ -211,6 +201,7 @@ def compress_for_output_listing(paths: Iterable[str]) -> Tuple[Set[str], Set[str
 class StashedUninstallPathSet:
     """A set of file rename operations to stash files while
     tentatively uninstalling them."""
+
     def __init__(self) -> None:
         # Mapping from source file root to [Adjacent]TempDirectory
         # for files under that directory.
@@ -252,7 +243,7 @@ class StashedUninstallPathSet:
         else:
             # Did not find any suitable root
             head = os.path.dirname(path)
-            save_dir = TempDirectory(kind='uninstall')
+            save_dir = TempDirectory(kind="uninstall")
             self._save_dirs[head] = save_dir
 
         relpath = os.path.relpath(path, head)
@@ -271,7 +262,7 @@ class StashedUninstallPathSet:
             new_path = self._get_file_stash(path)
 
         self._moves.append((path, new_path))
-        if (path_is_dir and os.path.isdir(new_path)):
+        if path_is_dir and os.path.isdir(new_path):
             # If we're moving a directory, we need to
             # remove the destination first or else it will be
             # moved to inside the existing directory.
@@ -295,7 +286,7 @@ class StashedUninstallPathSet:
 
         for new_path, path in self._moves:
             try:
-                logger.debug('Replacing %s from %s', new_path, path)
+                logger.debug("Replacing %s from %s", new_path, path)
                 if os.path.isfile(new_path) or os.path.islink(new_path):
                     os.unlink(new_path)
                 elif os.path.isdir(new_path):
@@ -315,12 +306,17 @@ class StashedUninstallPathSet:
 class UninstallPathSet:
     """A set of file paths to be removed in the uninstallation of a
     requirement."""
-    def __init__(self, dist: Distribution) -> None:
-        self.paths: Set[str] = set()
+
+    def __init__(self, dist: BaseDistribution) -> None:
+        self._paths: Set[str] = set()
         self._refuse: Set[str] = set()
-        self.pth: Dict[str, UninstallPthEntries] = {}
-        self.dist = dist
+        self._pth: Dict[str, UninstallPthEntries] = {}
+        self._dist = dist
         self._moved_paths = StashedUninstallPathSet()
+        # Create local cache of normalize_path results. Creating an UninstallPathSet
+        # can result in hundreds/thousands of redundant calls to normalize_path with
+        # the same args, which hurts performance.
+        self._normalize_path_cached = functools.lru_cache()(normalize_path)
 
     def _permitted(self, path: str) -> bool:
         """
@@ -328,70 +324,70 @@ class UninstallPathSet:
         remove/modify, False otherwise.
 
         """
-        return is_local(path)
+        # aka is_local, but caching normalized sys.prefix
+        if not running_under_virtualenv():
+            return True
+        return path.startswith(self._normalize_path_cached(sys.prefix))
 
     def add(self, path: str) -> None:
         head, tail = os.path.split(path)
 
         # we normalize the head to resolve parent directory symlinks, but not
         # the tail, since we only want to uninstall symlinks, not their targets
-        path = os.path.join(normalize_path(head), os.path.normcase(tail))
+        path = os.path.join(self._normalize_path_cached(head), os.path.normcase(tail))
 
         if not os.path.exists(path):
             return
         if self._permitted(path):
-            self.paths.add(path)
+            self._paths.add(path)
         else:
             self._refuse.add(path)
 
         # __pycache__ files can show up after 'installed-files.txt' is created,
         # due to imports
-        if os.path.splitext(path)[1] == '.py':
+        if os.path.splitext(path)[1] == ".py":
             self.add(cache_from_source(path))
 
     def add_pth(self, pth_file: str, entry: str) -> None:
-        pth_file = normalize_path(pth_file)
+        pth_file = self._normalize_path_cached(pth_file)
         if self._permitted(pth_file):
-            if pth_file not in self.pth:
-                self.pth[pth_file] = UninstallPthEntries(pth_file)
-            self.pth[pth_file].add(entry)
+            if pth_file not in self._pth:
+                self._pth[pth_file] = UninstallPthEntries(pth_file)
+            self._pth[pth_file].add(entry)
         else:
             self._refuse.add(pth_file)
 
     def remove(self, auto_confirm: bool = False, verbose: bool = False) -> None:
-        """Remove paths in ``self.paths`` with confirmation (unless
+        """Remove paths in ``self._paths`` with confirmation (unless
         ``auto_confirm`` is True)."""
 
-        if not self.paths:
+        if not self._paths:
             logger.info(
                 "Can't uninstall '%s'. No files were found to uninstall.",
-                self.dist.project_name,
+                self._dist.raw_name,
             )
             return
 
-        dist_name_version = (
-            self.dist.project_name + "-" + self.dist.version
-        )
-        logger.info('Uninstalling %s:', dist_name_version)
+        dist_name_version = f"{self._dist.raw_name}-{self._dist.version}"
+        logger.info("Uninstalling %s:", dist_name_version)
 
         with indent_log():
             if auto_confirm or self._allowed_to_proceed(verbose):
                 moved = self._moved_paths
 
-                for_rename = compress_for_rename(self.paths)
+                for_rename = compress_for_rename(self._paths)
 
                 for path in sorted(compact(for_rename)):
                     moved.stash(path)
-                    logger.verbose('Removing file or directory %s', path)
+                    logger.verbose("Removing file or directory %s", path)
 
-                for pth in self.pth.values():
+                for pth in self._pth.values():
                     pth.remove()
 
-                logger.info('Successfully uninstalled %s', dist_name_version)
+                logger.info("Successfully uninstalled %s", dist_name_version)
 
     def _allowed_to_proceed(self, verbose: bool) -> bool:
-        """Display which files would be deleted and prompt for confirmation
-        """
+        """Display which files would be deleted and prompt for confirmation"""
 
         def _display(msg: str, paths: Iterable[str]) -> None:
             if not paths:
@@ -403,32 +399,32 @@ class UninstallPathSet:
                     logger.info(path)
 
         if not verbose:
-            will_remove, will_skip = compress_for_output_listing(self.paths)
+            will_remove, will_skip = compress_for_output_listing(self._paths)
         else:
             # In verbose mode, display all the files that are going to be
             # deleted.
-            will_remove = set(self.paths)
+            will_remove = set(self._paths)
             will_skip = set()
 
-        _display('Would remove:', will_remove)
-        _display('Would not remove (might be manually added):', will_skip)
-        _display('Would not remove (outside of prefix):', self._refuse)
+        _display("Would remove:", will_remove)
+        _display("Would not remove (might be manually added):", will_skip)
+        _display("Would not remove (outside of prefix):", self._refuse)
         if verbose:
-            _display('Will actually move:', compress_for_rename(self.paths))
+            _display("Will actually move:", compress_for_rename(self._paths))
 
-        return ask('Proceed (Y/n)? ', ('y', 'n', '')) != 'n'
+        return ask("Proceed (Y/n)? ", ("y", "n", "")) != "n"
 
     def rollback(self) -> None:
         """Rollback the changes previously made by remove()."""
         if not self._moved_paths.can_rollback:
             logger.error(
                 "Can't roll back %s; was not uninstalled",
-                self.dist.project_name,
+                self._dist.raw_name,
             )
             return
-        logger.info('Rolling back uninstall of %s', self.dist.project_name)
+        logger.info("Rolling back uninstall of %s", self._dist.raw_name)
         self._moved_paths.rollback()
-        for pth in self.pth.values():
+        for pth in self._pth.values():
             pth.rollback()
 
     def commit(self) -> None:
@@ -436,132 +432,161 @@ class UninstallPathSet:
         self._moved_paths.commit()
 
     @classmethod
-    def from_dist(cls, dist: Distribution) -> "UninstallPathSet":
-        dist_path = normalize_path(dist.location)
-        if not dist_is_local(dist):
+    def from_dist(cls, dist: BaseDistribution) -> "UninstallPathSet":
+        dist_location = dist.location
+        info_location = dist.info_location
+        if dist_location is None:
+            logger.info(
+                "Not uninstalling %s since it is not installed",
+                dist.canonical_name,
+            )
+            return cls(dist)
+
+        normalized_dist_location = normalize_path(dist_location)
+        if not dist.local:
             logger.info(
                 "Not uninstalling %s at %s, outside environment %s",
-                dist.key,
-                dist_path,
+                dist.canonical_name,
+                normalized_dist_location,
                 sys.prefix,
             )
             return cls(dist)
 
-        if dist_path in {p for p in {sysconfig.get_path("stdlib"),
-                                     sysconfig.get_path("platstdlib")}
-                         if p}:
+        if normalized_dist_location in {
+            p
+            for p in {sysconfig.get_path("stdlib"), sysconfig.get_path("platstdlib")}
+            if p
+        }:
             logger.info(
                 "Not uninstalling %s at %s, as it is in the standard library.",
-                dist.key,
-                dist_path,
+                dist.canonical_name,
+                normalized_dist_location,
             )
             return cls(dist)
 
         paths_to_remove = cls(dist)
-        develop_egg_link = egg_link_path(dist)
-        develop_egg_link_egg_info = '{}.egg-info'.format(
-            pkg_resources.to_filename(dist.project_name))
-        egg_info_exists = dist.egg_info and os.path.exists(dist.egg_info)
-        # Special case for distutils installed package
-        distutils_egg_info = getattr(dist._provider, 'path', None)
+        develop_egg_link = egg_link_path_from_location(dist.raw_name)
+
+        # Distribution is installed with metadata in a "flat" .egg-info
+        # directory. This means it is not a modern .dist-info installation, an
+        # egg, or legacy editable.
+        setuptools_flat_installation = (
+            dist.installed_with_setuptools_egg_info
+            and info_location is not None
+            and os.path.exists(info_location)
+            # If dist is editable and the location points to a ``.egg-info``,
+            # we are in fact in the legacy editable case.
+            and not info_location.endswith(f"{dist.setuptools_filename}.egg-info")
+        )
 
         # Uninstall cases order do matter as in the case of 2 installs of the
         # same package, pip needs to uninstall the currently detected version
-        if (egg_info_exists and dist.egg_info.endswith('.egg-info') and
-                not dist.egg_info.endswith(develop_egg_link_egg_info)):
-            # if dist.egg_info.endswith(develop_egg_link_egg_info), we
-            # are in fact in the develop_egg_link case
-            paths_to_remove.add(dist.egg_info)
-            if dist.has_metadata('installed-files.txt'):
-                for installed_file in dist.get_metadata(
-                        'installed-files.txt').splitlines():
-                    path = os.path.normpath(
-                        os.path.join(dist.egg_info, installed_file)
-                    )
-                    paths_to_remove.add(path)
+        if setuptools_flat_installation:
+            if info_location is not None:
+                paths_to_remove.add(info_location)
+            installed_files = dist.iter_declared_entries()
+            if installed_files is not None:
+                for installed_file in installed_files:
+                    paths_to_remove.add(os.path.join(dist_location, installed_file))
             # FIXME: need a test for this elif block
             # occurs with --single-version-externally-managed/--record outside
             # of pip
-            elif dist.has_metadata('top_level.txt'):
-                if dist.has_metadata('namespace_packages.txt'):
-                    namespaces = dist.get_metadata('namespace_packages.txt')
-                else:
+            elif dist.is_file("top_level.txt"):
+                try:
+                    namespace_packages = dist.read_text("namespace_packages.txt")
+                except FileNotFoundError:
                     namespaces = []
+                else:
+                    namespaces = namespace_packages.splitlines(keepends=False)
                 for top_level_pkg in [
-                        p for p
-                        in dist.get_metadata('top_level.txt').splitlines()
-                        if p and p not in namespaces]:
-                    path = os.path.join(dist.location, top_level_pkg)
+                    p
+                    for p in dist.read_text("top_level.txt").splitlines()
+                    if p and p not in namespaces
+                ]:
+                    path = os.path.join(dist_location, top_level_pkg)
                     paths_to_remove.add(path)
-                    paths_to_remove.add(path + '.py')
-                    paths_to_remove.add(path + '.pyc')
-                    paths_to_remove.add(path + '.pyo')
+                    paths_to_remove.add(f"{path}.py")
+                    paths_to_remove.add(f"{path}.pyc")
+                    paths_to_remove.add(f"{path}.pyo")
 
-        elif distutils_egg_info:
+        elif dist.installed_by_distutils:
             raise UninstallationError(
                 "Cannot uninstall {!r}. It is a distutils installed project "
                 "and thus we cannot accurately determine which files belong "
                 "to it which would lead to only a partial uninstall.".format(
-                    dist.project_name,
+                    dist.raw_name,
                 )
             )
 
-        elif dist.location.endswith('.egg'):
+        elif dist.installed_as_egg:
             # package installed by easy_install
             # We cannot match on dist.egg_name because it can slightly vary
             # i.e. setuptools-0.6c11-py2.6.egg vs setuptools-0.6rc11-py2.6.egg
-            paths_to_remove.add(dist.location)
-            easy_install_egg = os.path.split(dist.location)[1]
-            easy_install_pth = os.path.join(os.path.dirname(dist.location),
-                                            'easy-install.pth')
-            paths_to_remove.add_pth(easy_install_pth, './' + easy_install_egg)
+            paths_to_remove.add(dist_location)
+            easy_install_egg = os.path.split(dist_location)[1]
+            easy_install_pth = os.path.join(
+                os.path.dirname(dist_location),
+                "easy-install.pth",
+            )
+            paths_to_remove.add_pth(easy_install_pth, "./" + easy_install_egg)
 
-        elif egg_info_exists and dist.egg_info.endswith('.dist-info'):
+        elif dist.installed_with_dist_info:
             for path in uninstallation_paths(dist):
                 paths_to_remove.add(path)
 
         elif develop_egg_link:
-            # develop egg
+            # PEP 660 modern editable is handled in the ``.dist-info`` case
+            # above, so this only covers the setuptools-style editable.
             with open(develop_egg_link) as fh:
                 link_pointer = os.path.normcase(fh.readline().strip())
-            assert (link_pointer == dist.location), (
-                'Egg-link {} does not match installed location of {} '
-                '(at {})'.format(
-                    link_pointer, dist.project_name, dist.location)
+                normalized_link_pointer = paths_to_remove._normalize_path_cached(
+                    link_pointer
+                )
+            assert os.path.samefile(
+                normalized_link_pointer, normalized_dist_location
+            ), (
+                f"Egg-link {develop_egg_link} (to {link_pointer}) does not match "
+                f"installed location of {dist.raw_name} (at {dist_location})"
             )
             paths_to_remove.add(develop_egg_link)
-            easy_install_pth = os.path.join(os.path.dirname(develop_egg_link),
-                                            'easy-install.pth')
-            paths_to_remove.add_pth(easy_install_pth, dist.location)
+            easy_install_pth = os.path.join(
+                os.path.dirname(develop_egg_link), "easy-install.pth"
+            )
+            paths_to_remove.add_pth(easy_install_pth, dist_location)
 
         else:
             logger.debug(
-                'Not sure how to uninstall: %s - Check: %s',
-                dist, dist.location,
+                "Not sure how to uninstall: %s - Check: %s",
+                dist,
+                dist_location,
             )
 
+        if dist.in_usersite:
+            bin_dir = get_bin_user()
+        else:
+            bin_dir = get_bin_prefix()
+
         # find distutils scripts= scripts
-        if dist.has_metadata('scripts') and dist.metadata_isdir('scripts'):
-            for script in dist.metadata_listdir('scripts'):
-                if dist_in_usersite(dist):
-                    bin_dir = get_bin_user()
-                else:
-                    bin_dir = get_bin_prefix()
+        try:
+            for script in dist.iter_distutils_script_names():
                 paths_to_remove.add(os.path.join(bin_dir, script))
                 if WINDOWS:
-                    paths_to_remove.add(os.path.join(bin_dir, script) + '.bat')
+                    paths_to_remove.add(os.path.join(bin_dir, f"{script}.bat"))
+        except (FileNotFoundError, NotADirectoryError):
+            pass
 
-        # find console_scripts
-        _scripts_to_remove = []
-        console_scripts = dist.get_entry_map(group='console_scripts')
-        for name in console_scripts.keys():
-            _scripts_to_remove.extend(_script_names(dist, name, False))
-        # find gui_scripts
-        gui_scripts = dist.get_entry_map(group='gui_scripts')
-        for name in gui_scripts.keys():
-            _scripts_to_remove.extend(_script_names(dist, name, True))
+        # find console_scripts and gui_scripts
+        def iter_scripts_to_remove(
+            dist: BaseDistribution,
+            bin_dir: str,
+        ) -> Generator[str, None, None]:
+            for entry_point in dist.iter_entry_points():
+                if entry_point.group == "console_scripts":
+                    yield from _script_names(bin_dir, entry_point.name, False)
+                elif entry_point.group == "gui_scripts":
+                    yield from _script_names(bin_dir, entry_point.name, True)
 
-        for s in _scripts_to_remove:
+        for s in iter_scripts_to_remove(dist, bin_dir):
             paths_to_remove.add(s)
 
         return paths_to_remove
@@ -585,45 +610,41 @@ class UninstallPthEntries:
         # have more than "\\sever\share". Valid examples: "\\server\share\" or
         # "\\server\share\folder".
         if WINDOWS and not os.path.splitdrive(entry)[0]:
-            entry = entry.replace('\\', '/')
+            entry = entry.replace("\\", "/")
         self.entries.add(entry)
 
     def remove(self) -> None:
-        logger.verbose('Removing pth entries from %s:', self.file)
+        logger.verbose("Removing pth entries from %s:", self.file)
 
         # If the file doesn't exist, log a warning and return
         if not os.path.isfile(self.file):
-            logger.warning(
-                "Cannot remove entries from nonexistent file %s", self.file
-            )
+            logger.warning("Cannot remove entries from nonexistent file %s", self.file)
             return
-        with open(self.file, 'rb') as fh:
+        with open(self.file, "rb") as fh:
             # windows uses '\r\n' with py3k, but uses '\n' with py2.x
             lines = fh.readlines()
             self._saved_lines = lines
-        if any(b'\r\n' in line for line in lines):
-            endline = '\r\n'
+        if any(b"\r\n" in line for line in lines):
+            endline = "\r\n"
         else:
-            endline = '\n'
+            endline = "\n"
         # handle missing trailing newline
         if lines and not lines[-1].endswith(endline.encode("utf-8")):
             lines[-1] = lines[-1] + endline.encode("utf-8")
         for entry in self.entries:
             try:
-                logger.verbose('Removing entry: %s', entry)
+                logger.verbose("Removing entry: %s", entry)
                 lines.remove((entry + endline).encode("utf-8"))
             except ValueError:
                 pass
-        with open(self.file, 'wb') as fh:
+        with open(self.file, "wb") as fh:
             fh.writelines(lines)
 
     def rollback(self) -> bool:
         if self._saved_lines is None:
-            logger.error(
-                'Cannot roll back changes to %s, none were made', self.file
-            )
+            logger.error("Cannot roll back changes to %s, none were made", self.file)
             return False
-        logger.debug('Rolling %s back to previous state', self.file)
-        with open(self.file, 'wb') as fh:
+        logger.debug("Rolling %s back to previous state", self.file)
+        with open(self.file, "wb") as fh:
             fh.writelines(self._saved_lines)
         return True

venv/Lib/site-packages/pip/_internal/resolution/base.py

@@ -1,9 +1,11 @@
-from typing import Callable, List
+from typing import Callable, List, Optional
 
 from pip._internal.req.req_install import InstallRequirement
 from pip._internal.req.req_set import RequirementSet
 
-InstallRequirementProvider = Callable[[str, InstallRequirement], InstallRequirement]
+InstallRequirementProvider = Callable[
+    [str, Optional[InstallRequirement]], InstallRequirement
+]
 
 
 class BaseResolver:

venv/Lib/site-packages/pip/_internal/resolution/legacy/resolver.py

@@ -20,7 +20,7 @@ from itertools import chain
 from typing import DefaultDict, Iterable, List, Optional, Set, Tuple
 
 from pip._vendor.packaging import specifiers
-from pip._vendor.pkg_resources import Distribution
+from pip._vendor.packaging.requirements import Requirement
 
 from pip._internal.cache import WheelCache
 from pip._internal.exceptions import (
@@ -28,10 +28,14 @@ from pip._internal.exceptions import (
     DistributionNotFound,
     HashError,
     HashErrors,
+    InstallationError,
+    NoneMetadataError,
     UnsupportedPythonVersion,
 )
 from pip._internal.index.package_finder import PackageFinder
+from pip._internal.metadata import BaseDistribution
 from pip._internal.models.link import Link
+from pip._internal.models.wheel import Wheel
 from pip._internal.operations.prepare import RequirementPreparer
 from pip._internal.req.req_install import (
     InstallRequirement,
@@ -39,10 +43,12 @@ from pip._internal.req.req_install import (
 )
 from pip._internal.req.req_set import RequirementSet
 from pip._internal.resolution.base import BaseResolver, InstallRequirementProvider
+from pip._internal.utils import compatibility_tags
 from pip._internal.utils.compatibility_tags import get_supported
+from pip._internal.utils.direct_url_helpers import direct_url_from_link
 from pip._internal.utils.logging import indent_log
-from pip._internal.utils.misc import dist_in_usersite, normalize_version_info
-from pip._internal.utils.packaging import check_requires_python, get_requires_python
+from pip._internal.utils.misc import normalize_version_info
+from pip._internal.utils.packaging import check_requires_python
 
 logger = logging.getLogger(__name__)
 
@@ -50,7 +56,7 @@ DiscoveredDependencies = DefaultDict[str, List[InstallRequirement]]
 
 
 def _check_dist_requires_python(
-    dist: Distribution,
+    dist: BaseDistribution,
     version_info: Tuple[int, int, int],
     ignore_requires_python: bool = False,
 ) -> None:
@@ -66,14 +72,21 @@ def _check_dist_requires_python(
     :raises UnsupportedPythonVersion: When the given Python version isn't
         compatible.
     """
-    requires_python = get_requires_python(dist)
+    # This idiosyncratically converts the SpecifierSet to str and let
+    # check_requires_python then parse it again into SpecifierSet. But this
+    # is the legacy resolver so I'm just not going to bother refactoring.
+    try:
+        requires_python = str(dist.requires_python)
+    except FileNotFoundError as e:
+        raise NoneMetadataError(dist, str(e))
     try:
         is_compatible = check_requires_python(
-            requires_python, version_info=version_info
+            requires_python,
+            version_info=version_info,
         )
     except specifiers.InvalidSpecifier as exc:
         logger.warning(
-            "Package %r has an invalid Requires-Python: %s", dist.project_name, exc
+            "Package %r has an invalid Requires-Python: %s", dist.raw_name, exc
         )
         return
 
@@ -84,7 +97,7 @@ def _check_dist_requires_python(
     if ignore_requires_python:
         logger.debug(
             "Ignoring failed Requires-Python check for package %r: %s not in %r",
-            dist.project_name,
+            dist.raw_name,
             version,
             requires_python,
         )
@@ -92,7 +105,7 @@ def _check_dist_requires_python(
 
     raise UnsupportedPythonVersion(
         "Package {!r} requires a different Python: {} not in {!r}".format(
-            dist.project_name, version, requires_python
+            dist.raw_name, version, requires_python
         )
     )
 
@@ -159,7 +172,7 @@ class Resolver(BaseResolver):
         for req in root_reqs:
             if req.constraint:
                 check_invalid_constraint_type(req)
-            requirement_set.add_requirement(req)
+            self._add_requirement_to_set(requirement_set, req)
 
         # Actually prepare the files, and collect any exceptions. Most hash
         # exceptions cannot be checked ahead of time, because
@@ -179,6 +192,124 @@ class Resolver(BaseResolver):
 
         return requirement_set
 
+    def _add_requirement_to_set(
+        self,
+        requirement_set: RequirementSet,
+        install_req: InstallRequirement,
+        parent_req_name: Optional[str] = None,
+        extras_requested: Optional[Iterable[str]] = None,
+    ) -> Tuple[List[InstallRequirement], Optional[InstallRequirement]]:
+        """Add install_req as a requirement to install.
+
+        :param parent_req_name: The name of the requirement that needed this
+            added. The name is used because when multiple unnamed requirements
+            resolve to the same name, we could otherwise end up with dependency
+            links that point outside the Requirements set. parent_req must
+            already be added. Note that None implies that this is a user
+            supplied requirement, vs an inferred one.
+        :param extras_requested: an iterable of extras used to evaluate the
+            environment markers.
+        :return: Additional requirements to scan. That is either [] if
+            the requirement is not applicable, or [install_req] if the
+            requirement is applicable and has just been added.
+        """
+        # If the markers do not match, ignore this requirement.
+        if not install_req.match_markers(extras_requested):
+            logger.info(
+                "Ignoring %s: markers '%s' don't match your environment",
+                install_req.name,
+                install_req.markers,
+            )
+            return [], None
+
+        # If the wheel is not supported, raise an error.
+        # Should check this after filtering out based on environment markers to
+        # allow specifying different wheels based on the environment/OS, in a
+        # single requirements file.
+        if install_req.link and install_req.link.is_wheel:
+            wheel = Wheel(install_req.link.filename)
+            tags = compatibility_tags.get_supported()
+            if requirement_set.check_supported_wheels and not wheel.supported(tags):
+                raise InstallationError(
+                    "{} is not a supported wheel on this platform.".format(
+                        wheel.filename
+                    )
+                )
+
+        # This next bit is really a sanity check.
+        assert (
+            not install_req.user_supplied or parent_req_name is None
+        ), "a user supplied req shouldn't have a parent"
+
+        # Unnamed requirements are scanned again and the requirement won't be
+        # added as a dependency until after scanning.
+        if not install_req.name:
+            requirement_set.add_unnamed_requirement(install_req)
+            return [install_req], None
+
+        try:
+            existing_req: Optional[
+                InstallRequirement
+            ] = requirement_set.get_requirement(install_req.name)
+        except KeyError:
+            existing_req = None
+
+        has_conflicting_requirement = (
+            parent_req_name is None
+            and existing_req
+            and not existing_req.constraint
+            and existing_req.extras == install_req.extras
+            and existing_req.req
+            and install_req.req
+            and existing_req.req.specifier != install_req.req.specifier
+        )
+        if has_conflicting_requirement:
+            raise InstallationError(
+                "Double requirement given: {} (already in {}, name={!r})".format(
+                    install_req, existing_req, install_req.name
+                )
+            )
+
+        # When no existing requirement exists, add the requirement as a
+        # dependency and it will be scanned again after.
+        if not existing_req:
+            requirement_set.add_named_requirement(install_req)
+            # We'd want to rescan this requirement later
+            return [install_req], install_req
+
+        # Assume there's no need to scan, and that we've already
+        # encountered this for scanning.
+        if install_req.constraint or not existing_req.constraint:
+            return [], existing_req
+
+        does_not_satisfy_constraint = install_req.link and not (
+            existing_req.link and install_req.link.path == existing_req.link.path
+        )
+        if does_not_satisfy_constraint:
+            raise InstallationError(
+                "Could not satisfy constraints for '{}': "
+                "installation from path or url cannot be "
+                "constrained to a version".format(install_req.name)
+            )
+        # If we're now installing a constraint, mark the existing
+        # object for real installation.
+        existing_req.constraint = False
+        # If we're now installing a user supplied requirement,
+        # mark the existing object as such.
+        if install_req.user_supplied:
+            existing_req.user_supplied = True
+        existing_req.extras = tuple(
+            sorted(set(existing_req.extras) | set(install_req.extras))
+        )
+        logger.debug(
+            "Setting %s extras to: %s",
+            existing_req,
+            existing_req.extras,
+        )
+        # Return the existing requirement for addition to the parent and
+        # scanning again.
+        return [existing_req], existing_req
+
     def _is_upgrade_allowed(self, req: InstallRequirement) -> bool:
         if self.upgrade_strategy == "to-satisfy-only":
             return False
@@ -194,7 +325,7 @@ class Resolver(BaseResolver):
         """
         # Don't uninstall the conflict if doing a user install and the
         # conflict is not a user install.
-        if not self.use_user_site or dist_in_usersite(req.satisfied_by):
+        if not self.use_user_site or req.satisfied_by.in_usersite:
             req.should_reinstall = True
         req.satisfied_by = None
 
@@ -300,10 +431,18 @@ class Resolver(BaseResolver):
         if cache_entry is not None:
             logger.debug("Using cached wheel link: %s", cache_entry.link)
             if req.link is req.original_link and cache_entry.persistent:
-                req.original_link_is_in_wheel_cache = True
+                req.cached_wheel_source_link = req.link
+            if cache_entry.origin is not None:
+                req.download_info = cache_entry.origin
+            else:
+                # Legacy cache entry that does not have origin.json.
+                # download_info may miss the archive_info.hashes field.
+                req.download_info = direct_url_from_link(
+                    req.link, link_is_in_wheel_cache=cache_entry.persistent
+                )
             req.link = cache_entry.link
 
-    def _get_dist_for(self, req: InstallRequirement) -> Distribution:
+    def _get_dist_for(self, req: InstallRequirement) -> BaseDistribution:
         """Takes a InstallRequirement and returns a single AbstractDist \
         representing a prepared variant of the same.
         """
@@ -378,13 +517,14 @@ class Resolver(BaseResolver):
 
         more_reqs: List[InstallRequirement] = []
 
-        def add_req(subreq: Distribution, extras_requested: Iterable[str]) -> None:
-            sub_install_req = self._make_install_req(
-                str(subreq),
-                req_to_install,
-            )
+        def add_req(subreq: Requirement, extras_requested: Iterable[str]) -> None:
+            # This idiosyncratically converts the Requirement to str and let
+            # make_install_req then parse it again into Requirement. But this is
+            # the legacy resolver so I'm just not going to bother refactoring.
+            sub_install_req = self._make_install_req(str(subreq), req_to_install)
             parent_req_name = req_to_install.name
-            to_scan_again, add_to_parent = requirement_set.add_requirement(
+            to_scan_again, add_to_parent = self._add_requirement_to_set(
+                requirement_set,
                 sub_install_req,
                 parent_req_name=parent_req_name,
                 extras_requested=extras_requested,
@@ -401,7 +541,9 @@ class Resolver(BaseResolver):
                 # 'unnamed' requirements can only come from being directly
                 # provided by the user.
                 assert req_to_install.user_supplied
-                requirement_set.add_requirement(req_to_install, parent_req_name=None)
+                self._add_requirement_to_set(
+                    requirement_set, req_to_install, parent_req_name=None
+                )
 
             if not self.ignore_dependencies:
                 if req_to_install.extras:
@@ -410,15 +552,20 @@ class Resolver(BaseResolver):
                         ",".join(req_to_install.extras),
                     )
                 missing_requested = sorted(
-                    set(req_to_install.extras) - set(dist.extras)
+                    set(req_to_install.extras) - set(dist.iter_provided_extras())
                 )
                 for missing in missing_requested:
-                    logger.warning("%s does not provide the extra '%s'", dist, missing)
+                    logger.warning(
+                        "%s %s does not provide the extra '%s'",
+                        dist.raw_name,
+                        dist.version,
+                        missing,
+                    )
 
                 available_requested = sorted(
-                    set(dist.extras) & set(req_to_install.extras)
+                    set(dist.iter_provided_extras()) & set(req_to_install.extras)
                 )
-                for subreq in dist.requires(available_requested):
+                for subreq in dist.iter_dependencies(available_requested):
                     add_req(subreq, extras_requested=available_requested)
 
         return more_reqs

venv/Lib/site-packages/pip/_internal/resolution/resolvelib/base.py

@@ -36,11 +36,8 @@ class Constraint:
         links = frozenset([ireq.link]) if ireq.link else frozenset()
         return Constraint(ireq.specifier, ireq.hashes(trust_internet=False), links)
 
-    def __nonzero__(self) -> bool:
-        return bool(self.specifier) or bool(self.hashes) or bool(self.links)
-
     def __bool__(self) -> bool:
-        return self.__nonzero__()
+        return bool(self.specifier) or bool(self.hashes) or bool(self.links)
 
     def __and__(self, other: InstallRequirement) -> "Constraint":
         if not isinstance(other, InstallRequirement):

venv/Lib/site-packages/pip/_internal/resolution/resolvelib/candidates.py

@@ -2,13 +2,15 @@ import logging
 import sys
 from typing import TYPE_CHECKING, Any, FrozenSet, Iterable, Optional, Tuple, Union, cast
 
-from pip._vendor.packaging.specifiers import InvalidSpecifier, SpecifierSet
 from pip._vendor.packaging.utils import NormalizedName, canonicalize_name
 from pip._vendor.packaging.version import Version
-from pip._vendor.packaging.version import parse as parse_version
-from pip._vendor.pkg_resources import Distribution
 
-from pip._internal.exceptions import HashError, MetadataInconsistent
+from pip._internal.exceptions import (
+    HashError,
+    InstallationSubprocessError,
+    MetadataInconsistent,
+)
+from pip._internal.metadata import BaseDistribution
 from pip._internal.models.link import Link, links_equivalent
 from pip._internal.models.wheel import Wheel
 from pip._internal.req.constructors import (
@@ -16,8 +18,8 @@ from pip._internal.req.constructors import (
     install_req_from_line,
 )
 from pip._internal.req.req_install import InstallRequirement
-from pip._internal.utils.misc import dist_is_editable, normalize_version_info
-from pip._internal.utils.packaging import get_requires_python
+from pip._internal.utils.direct_url_helpers import direct_url_from_link
+from pip._internal.utils.misc import normalize_version_info
 
 from .base import Candidate, CandidateVersion, Requirement, format_name
 
@@ -63,14 +65,13 @@ def make_install_req_from_link(
         use_pep517=template.use_pep517,
         isolated=template.isolated,
         constraint=template.constraint,
-        options=dict(
-            install_options=template.install_options,
-            global_options=template.global_options,
-            hashes=template.hash_options,
-        ),
+        global_options=template.global_options,
+        hash_options=template.hash_options,
+        config_settings=template.config_settings,
     )
     ireq.original_link = template.original_link
     ireq.link = link
+    ireq.extras = template.extras
     return ireq
 
 
@@ -78,31 +79,31 @@ def make_install_req_from_editable(
     link: Link, template: InstallRequirement
 ) -> InstallRequirement:
     assert template.editable, "template not editable"
-    return install_req_from_editable(
+    ireq = install_req_from_editable(
         link.url,
         user_supplied=template.user_supplied,
         comes_from=template.comes_from,
         use_pep517=template.use_pep517,
         isolated=template.isolated,
         constraint=template.constraint,
-        options=dict(
-            install_options=template.install_options,
-            global_options=template.global_options,
-            hashes=template.hash_options,
-        ),
+        permit_editable_wheels=template.permit_editable_wheels,
+        global_options=template.global_options,
+        hash_options=template.hash_options,
+        config_settings=template.config_settings,
     )
+    ireq.extras = template.extras
+    return ireq
 
 
-def make_install_req_from_dist(
-    dist: Distribution, template: InstallRequirement
+def _make_install_req_from_dist(
+    dist: BaseDistribution, template: InstallRequirement
 ) -> InstallRequirement:
-    project_name = canonicalize_name(dist.project_name)
     if template.req:
         line = str(template.req)
     elif template.link:
-        line = f"{project_name} @ {template.link.url}"
+        line = f"{dist.canonical_name} @ {template.link.url}"
     else:
-        line = f"{project_name}=={dist.parsed_version}"
+        line = f"{dist.canonical_name}=={dist.version}"
     ireq = install_req_from_line(
         line,
         user_supplied=template.user_supplied,
@@ -110,11 +111,9 @@ def make_install_req_from_dist(
         use_pep517=template.use_pep517,
         isolated=template.isolated,
         constraint=template.constraint,
-        options=dict(
-            install_options=template.install_options,
-            global_options=template.global_options,
-            hashes=template.hash_options,
-        ),
+        global_options=template.global_options,
+        hash_options=template.hash_options,
+        config_settings=template.config_settings,
     )
     ireq.satisfied_by = dist
     return ireq
@@ -136,6 +135,7 @@ class _InstallRequirementBackedCandidate(Candidate):
         found remote link (e.g. from pypi.org).
     """
 
+    dist: BaseDistribution
     is_installed = False
 
     def __init__(
@@ -180,7 +180,7 @@ class _InstallRequirementBackedCandidate(Candidate):
     def project_name(self) -> NormalizedName:
         """The normalised name of the project the candidate refers to"""
         if self._name is None:
-            self._name = canonicalize_name(self.dist.project_name)
+            self._name = self.dist.canonical_name
         return self._name
 
     @property
@@ -190,7 +190,7 @@ class _InstallRequirementBackedCandidate(Candidate):
     @property
     def version(self) -> CandidateVersion:
         if self._version is None:
-            self._version = parse_version(self.dist.version)
+            self._version = self.dist.version
         return self._version
 
     def format_for_error(self) -> str:
@@ -200,29 +200,27 @@ class _InstallRequirementBackedCandidate(Candidate):
             self._link.file_path if self._link.is_file else self._link,
         )
 
-    def _prepare_distribution(self) -> Distribution:
+    def _prepare_distribution(self) -> BaseDistribution:
         raise NotImplementedError("Override in subclass")
 
-    def _check_metadata_consistency(self, dist: Distribution) -> None:
+    def _check_metadata_consistency(self, dist: BaseDistribution) -> None:
         """Check for consistency of project name and version of dist."""
-        canonical_name = canonicalize_name(dist.project_name)
-        if self._name is not None and self._name != canonical_name:
+        if self._name is not None and self._name != dist.canonical_name:
             raise MetadataInconsistent(
                 self._ireq,
                 "name",
                 self._name,
-                dist.project_name,
+                dist.canonical_name,
             )
-        parsed_version = parse_version(dist.version)
-        if self._version is not None and self._version != parsed_version:
+        if self._version is not None and self._version != dist.version:
             raise MetadataInconsistent(
                 self._ireq,
                 "version",
                 str(self._version),
-                dist.version,
+                str(dist.version),
             )
 
-    def _prepare(self) -> Distribution:
+    def _prepare(self) -> BaseDistribution:
         try:
             dist = self._prepare_distribution()
         except HashError as e:
@@ -231,26 +229,19 @@ class _InstallRequirementBackedCandidate(Candidate):
             # offending line to the user.
             e.req = self._ireq
             raise
+        except InstallationSubprocessError as exc:
+            # The output has been presented already, so don't duplicate it.
+            exc.context = "See above for output."
+            raise
+
         self._check_metadata_consistency(dist)
         return dist
 
-    def _get_requires_python_dependency(self) -> Optional[Requirement]:
-        requires_python = get_requires_python(self.dist)
-        if requires_python is None:
-            return None
-        try:
-            spec = SpecifierSet(requires_python)
-        except InvalidSpecifier as e:
-            message = "Package %r has an invalid Requires-Python: %s"
-            logger.warning(message, self.name, e)
-            return None
-        return self._factory.make_requires_python_requirement(spec)
-
     def iter_dependencies(self, with_requires: bool) -> Iterable[Optional[Requirement]]:
-        requires = self.dist.requires() if with_requires else ()
+        requires = self.dist.iter_dependencies() if with_requires else ()
         for r in requires:
             yield self._factory.make_requirement_from_spec(str(r), self._ireq)
-        yield self._get_requires_python_dependency()
+        yield self._factory.make_requires_python_requirement(self.dist.requires_python)
 
     def get_install_requirement(self) -> Optional[InstallRequirement]:
         return self._ireq
@@ -268,7 +259,7 @@ class LinkCandidate(_InstallRequirementBackedCandidate):
         version: Optional[CandidateVersion] = None,
     ) -> None:
         source_link = link
-        cache_entry = factory.get_wheel_cache_entry(link, name)
+        cache_entry = factory.get_wheel_cache_entry(source_link, name)
         if cache_entry is not None:
             logger.debug("Using cached wheel link: %s", cache_entry.link)
             link = cache_entry.link
@@ -285,12 +276,19 @@ class LinkCandidate(_InstallRequirementBackedCandidate):
                     version, wheel_version, name
                 )
 
-        if (
-            cache_entry is not None
-            and cache_entry.persistent
-            and template.link is template.original_link
-        ):
-            ireq.original_link_is_in_wheel_cache = True
+        if cache_entry is not None:
+            assert ireq.link.is_wheel
+            assert ireq.link.is_file
+            if cache_entry.persistent and template.link is template.original_link:
+                ireq.cached_wheel_source_link = source_link
+            if cache_entry.origin is not None:
+                ireq.download_info = cache_entry.origin
+            else:
+                # Legacy cache entry that does not have origin.json.
+                # download_info may miss the archive_info.hashes field.
+                ireq.download_info = direct_url_from_link(
+                    source_link, link_is_in_wheel_cache=cache_entry.persistent
+                )
 
         super().__init__(
             link=link,
@@ -301,10 +299,9 @@ class LinkCandidate(_InstallRequirementBackedCandidate):
             version=version,
         )
 
-    def _prepare_distribution(self) -> Distribution:
-        return self._factory.preparer.prepare_linked_requirement(
-            self._ireq, parallel_builds=True
-        )
+    def _prepare_distribution(self) -> BaseDistribution:
+        preparer = self._factory.preparer
+        return preparer.prepare_linked_requirement(self._ireq, parallel_builds=True)
 
 
 class EditableCandidate(_InstallRequirementBackedCandidate):
@@ -327,7 +324,7 @@ class EditableCandidate(_InstallRequirementBackedCandidate):
             version=version,
         )
 
-    def _prepare_distribution(self) -> Distribution:
+    def _prepare_distribution(self) -> BaseDistribution:
         return self._factory.preparer.prepare_editable_requirement(self._ireq)
 
 
@@ -337,17 +334,17 @@ class AlreadyInstalledCandidate(Candidate):
 
     def __init__(
         self,
-        dist: Distribution,
+        dist: BaseDistribution,
         template: InstallRequirement,
         factory: "Factory",
     ) -> None:
         self.dist = dist
-        self._ireq = make_install_req_from_dist(dist, template)
+        self._ireq = _make_install_req_from_dist(dist, template)
         self._factory = factory
 
         # This is just logging some messages, so we can do it eagerly.
         # The returned dist would be exactly the same as self.dist because we
-        # set satisfied_by in make_install_req_from_dist.
+        # set satisfied_by in _make_install_req_from_dist.
         # TODO: Supply reason based on force_reinstall and upgrade_strategy.
         skip_reason = "already satisfied"
         factory.preparer.prepare_installed_requirement(self._ireq, skip_reason)
@@ -371,7 +368,7 @@ class AlreadyInstalledCandidate(Candidate):
 
     @property
     def project_name(self) -> NormalizedName:
-        return canonicalize_name(self.dist.project_name)
+        return self.dist.canonical_name
 
     @property
     def name(self) -> str:
@@ -379,11 +376,11 @@ class AlreadyInstalledCandidate(Candidate):
 
     @property
     def version(self) -> CandidateVersion:
-        return parse_version(self.dist.version)
+        return self.dist.version
 
     @property
     def is_editable(self) -> bool:
-        return dist_is_editable(self.dist)
+        return self.dist.editable
 
     def format_for_error(self) -> str:
         return f"{self.name} {self.version} (Installed)"
@@ -391,7 +388,7 @@ class AlreadyInstalledCandidate(Candidate):
     def iter_dependencies(self, with_requires: bool) -> Iterable[Optional[Requirement]]:
         if not with_requires:
             return
-        for r in self.dist.requires():
+        for r in self.dist.iter_dependencies():
             yield self._factory.make_requirement_from_spec(str(r), self._ireq)
 
     def get_install_requirement(self) -> Optional[InstallRequirement]:
@@ -491,8 +488,8 @@ class ExtrasCandidate(Candidate):
 
         # The user may have specified extras that the candidate doesn't
         # support. We ignore any unsupported extras here.
-        valid_extras = self.extras.intersection(self.base.dist.extras)
-        invalid_extras = self.extras.difference(self.base.dist.extras)
+        valid_extras = self.extras.intersection(self.base.dist.iter_provided_extras())
+        invalid_extras = self.extras.difference(self.base.dist.iter_provided_extras())
         for extra in sorted(invalid_extras):
             logger.warning(
                 "%s %s does not provide the extra '%s'",
@@ -501,7 +498,7 @@ class ExtrasCandidate(Candidate):
                 extra,
             )
 
-        for r in self.base.dist.requires(valid_extras):
+        for r in self.base.dist.iter_dependencies(valid_extras):
             requirement = factory.make_requirement_from_spec(
                 str(r), self.base._ireq, valid_extras
             )

venv/Lib/site-packages/pip/_internal/resolution/resolvelib/factory.py

@@ -19,7 +19,6 @@ from typing import (
 )
 
 from pip._vendor.packaging.requirements import InvalidRequirement
-from pip._vendor.packaging.requirements import Requirement as PackagingRequirement
 from pip._vendor.packaging.specifiers import SpecifierSet
 from pip._vendor.packaging.utils import NormalizedName, canonicalize_name
 from pip._vendor.resolvelib import ResolutionImpossible
@@ -28,7 +27,6 @@ from pip._internal.cache import CacheEntry, WheelCache
 from pip._internal.exceptions import (
     DistributionNotFound,
     InstallationError,
-    InstallationSubprocessError,
     MetadataInconsistent,
     UnsupportedPythonVersion,
     UnsupportedWheel,
@@ -46,6 +44,7 @@ from pip._internal.req.req_install import (
 from pip._internal.resolution.base import InstallRequirementProvider
 from pip._internal.utils.compatibility_tags import get_supported
 from pip._internal.utils.hashes import Hashes
+from pip._internal.utils.packaging import get_requirement
 from pip._internal.utils.virtualenv import running_under_virtualenv
 
 from .base import Candidate, CandidateVersion, Constraint, Requirement
@@ -158,10 +157,7 @@ class Factory:
         try:
             base = self._installed_candidate_cache[dist.canonical_name]
         except KeyError:
-            from pip._internal.metadata.pkg_resources import Distribution as _Dist
-
-            compat_dist = cast(_Dist, dist)._dist
-            base = AlreadyInstalledCandidate(compat_dist, template, factory=self)
+            base = AlreadyInstalledCandidate(dist, template, factory=self)
             self._installed_candidate_cache[dist.canonical_name] = base
         if not extras:
             return base
@@ -193,10 +189,16 @@ class Factory:
                         name=name,
                         version=version,
                     )
-                except (InstallationSubprocessError, MetadataInconsistent) as e:
-                    logger.warning("Discarding %s. %s", link, e)
+                except MetadataInconsistent as e:
+                    logger.info(
+                        "Discarding [blue underline]%s[/]: [yellow]%s[reset]",
+                        link,
+                        e,
+                        extra={"markup": True},
+                    )
                     self._build_failures[link] = e
                     return None
+
             base: BaseCandidate = self._editable_candidate_cache[link]
         else:
             if link not in self._link_candidate_cache:
@@ -208,8 +210,13 @@ class Factory:
                         name=name,
                         version=version,
                     )
-                except (InstallationSubprocessError, MetadataInconsistent) as e:
-                    logger.warning("Discarding %s. %s", link, e)
+                except MetadataInconsistent as e:
+                    logger.info(
+                        "Discarding [blue underline]%s[/]: [yellow]%s[reset]",
+                        link,
+                        e,
+                        extra={"markup": True},
+                    )
                     self._build_failures[link] = e
                     return None
             base = self._link_candidate_cache[link]
@@ -263,7 +270,7 @@ class Factory:
                 extras=extras,
                 template=template,
             )
-            # The candidate is a known incompatiblity. Don't use it.
+            # The candidate is a known incompatibility. Don't use it.
             if id(candidate) in incompatible_ids:
                 return None
             return candidate
@@ -276,14 +283,27 @@ class Factory:
             )
             icans = list(result.iter_applicable())
 
-            # PEP 592: Yanked releases must be ignored unless only yanked
-            # releases can satisfy the version range. So if this is false,
-            # all yanked icans need to be skipped.
+            # PEP 592: Yanked releases are ignored unless the specifier
+            # explicitly pins a version (via '==' or '===') that can be
+            # solely satisfied by a yanked release.
             all_yanked = all(ican.link.is_yanked for ican in icans)
 
+            def is_pinned(specifier: SpecifierSet) -> bool:
+                for sp in specifier:
+                    if sp.operator == "===":
+                        return True
+                    if sp.operator != "==":
+                        continue
+                    if sp.version.endswith(".*"):
+                        continue
+                    return True
+                return False
+
+            pinned = is_pinned(specifier)
+
             # PackageFinder returns earlier versions first, so we reverse.
             for ican in reversed(icans):
-                if not all_yanked and ican.link.is_yanked:
+                if not (all_yanked and pinned) and ican.link.is_yanked:
                     continue
                 func = functools.partial(
                     self._make_candidate_from_link,
@@ -350,7 +370,7 @@ class Factory:
     def find_candidates(
         self,
         identifier: str,
-        requirements: Mapping[str, Iterator[Requirement]],
+        requirements: Mapping[str, Iterable[Requirement]],
         incompatibilities: Mapping[str, Iterator[Candidate]],
         constraint: Constraint,
         prefers_installed: bool,
@@ -368,7 +388,7 @@ class Factory:
         # If the current identifier contains extras, add explicit candidates
         # from entries from extra-less identifier.
         with contextlib.suppress(InvalidRequirement):
-            parsed_requirement = PackagingRequirement(identifier)
+            parsed_requirement = get_requirement(identifier)
             explicit_candidates.update(
                 self._iter_explicit_candidates_from_base(
                     requirements.get(parsed_requirement.name, ()),
@@ -377,7 +397,7 @@ class Factory:
             )
 
         # Add explicit candidates from constraints. We only do this if there are
-        # kown ireqs, which represent requirements not already explicit. If
+        # known ireqs, which represent requirements not already explicit. If
         # there are no ireqs, we're constraining already-explicit requirements,
         # which is handled later when we return the explicit candidates.
         if ireqs:
@@ -487,16 +507,20 @@ class Factory:
     def make_requirement_from_spec(
         self,
         specifier: str,
-        comes_from: InstallRequirement,
+        comes_from: Optional[InstallRequirement],
         requested_extras: Iterable[str] = (),
     ) -> Optional[Requirement]:
         ireq = self._make_install_req_from_spec(specifier, comes_from)
         return self._make_requirement_from_install_req(ireq, requested_extras)
 
     def make_requires_python_requirement(
-        self, specifier: Optional[SpecifierSet]
+        self,
+        specifier: SpecifierSet,
     ) -> Optional[Requirement]:
-        if self._ignore_requires_python or specifier is None:
+        if self._ignore_requires_python:
+            return None
+        # Don't bother creating a dependency for an empty Requires-Python.
+        if not str(specifier):
             return None
         return RequiresPythonRequirement(specifier, self._python_candidate)
 
@@ -511,7 +535,7 @@ class Factory:
         hash mismatches. Furthermore, cached wheels at present have
         nondeterministic contents due to file modification times.
         """
-        if self._wheel_cache is None or self.preparer.require_hashes:
+        if self._wheel_cache is None:
             return None
         return self._wheel_cache.get_cache_entry(
             link=link,
@@ -578,8 +602,15 @@ class Factory:
             req_disp = f"{req} (from {parent.name})"
 
         cands = self._finder.find_all_candidates(req.project_name)
+        skipped_by_requires_python = self._finder.requires_python_skipped_reasons()
         versions = [str(v) for v in sorted({c.version for c in cands})]
 
+        if skipped_by_requires_python:
+            logger.critical(
+                "Ignored the following versions that require a different python "
+                "version: %s",
+                "; ".join(skipped_by_requires_python) or "none",
+            )
         logger.critical(
             "Could not find a version that satisfies the requirement %s "
             "(from versions: %s)",
@@ -601,7 +632,6 @@ class Factory:
         e: "ResolutionImpossible[Requirement, Candidate]",
         constraints: Dict[str, Constraint],
     ) -> InstallationError:
-
         assert e.causes, "Installation error reported with no cause"
 
         # If one of the things we can't solve is "we need Python X.Y",
@@ -614,7 +644,7 @@ class Factory:
         ]
         if requires_python_causes:
             # The comprehension above makes sure all Requirement instances are
-            # RequiresPythonRequirement, so let's cast for convinience.
+            # RequiresPythonRequirement, so let's cast for convenience.
             return self._report_requires_python_error(
                 cast("Sequence[ConflictCause]", requires_python_causes),
             )
@@ -695,6 +725,6 @@ class Factory:
 
         return DistributionNotFound(
             "ResolutionImpossible: for help visit "
-            "https://pip.pypa.io/en/latest/user_guide/"
-            "#fixing-conflicting-dependencies"
+            "https://pip.pypa.io/en/latest/topics/dependency-resolution/"
+            "#dealing-with-dependency-conflicts"
         )

venv/Lib/site-packages/pip/_internal/resolution/resolvelib/found_candidates.py

@@ -9,15 +9,30 @@ something.
 """
 
 import functools
-from typing import Callable, Iterator, Optional, Set, Tuple
+from collections.abc import Sequence
+from typing import TYPE_CHECKING, Any, Callable, Iterator, Optional, Set, Tuple
 
 from pip._vendor.packaging.version import _BaseVersion
-from pip._vendor.six.moves import collections_abc  # type: ignore
 
 from .base import Candidate
 
 IndexCandidateInfo = Tuple[_BaseVersion, Callable[[], Optional[Candidate]]]
 
+if TYPE_CHECKING:
+    SequenceCandidate = Sequence[Candidate]
+else:
+    # For compatibility: Python before 3.9 does not support using [] on the
+    # Sequence class.
+    #
+    # >>> from collections.abc import Sequence
+    # >>> Sequence[str]
+    # Traceback (most recent call last):
+    #   File "<stdin>", line 1, in <module>
+    # TypeError: 'ABCMeta' object is not subscriptable
+    #
+    # TODO: Remove this block after dropping Python 3.8 support.
+    SequenceCandidate = Sequence
+
 
 def _iter_built(infos: Iterator[IndexCandidateInfo]) -> Iterator[Candidate]:
     """Iterator for ``FoundCandidates``.
@@ -90,7 +105,7 @@ def _iter_built_with_inserted(
         yield installed
 
 
-class FoundCandidates(collections_abc.Sequence):
+class FoundCandidates(SequenceCandidate):
     """A lazy sequence to provide candidates to the resolver.
 
     The intended usage is to return this from `find_matches()` so the resolver
@@ -111,7 +126,7 @@ class FoundCandidates(collections_abc.Sequence):
         self._prefers_installed = prefers_installed
         self._incompatible_ids = incompatible_ids
 
-    def __getitem__(self, index: int) -> Candidate:
+    def __getitem__(self, index: Any) -> Any:
         # Implemented to satisfy the ABC check. This is not needed by the
         # resolver, and should not be used by the provider either (for
         # performance reasons).
@@ -138,5 +153,3 @@ class FoundCandidates(collections_abc.Sequence):
         if self._prefers_installed and self._installed:
             return True
         return any(self)
-
-    __nonzero__ = __bool__  # XXX: Python 2.

venv/Lib/site-packages/pip/_internal/resolution/resolvelib/provider.py

@@ -1,6 +1,15 @@
 import collections
 import math
-from typing import TYPE_CHECKING, Dict, Iterable, Iterator, Mapping, Sequence, Union
+from typing import (
+    TYPE_CHECKING,
+    Dict,
+    Iterable,
+    Iterator,
+    Mapping,
+    Sequence,
+    TypeVar,
+    Union,
+)
 
 from pip._vendor.resolvelib.providers import AbstractProvider
 
@@ -37,6 +46,35 @@ else:
 # services to those objects (access to pip's finder and preparer).
 
 
+D = TypeVar("D")
+V = TypeVar("V")
+
+
+def _get_with_identifier(
+    mapping: Mapping[str, V],
+    identifier: str,
+    default: D,
+) -> Union[D, V]:
+    """Get item from a package name lookup mapping with a resolver identifier.
+
+    This extra logic is needed when the target mapping is keyed by package
+    name, which cannot be directly looked up with an identifier (which may
+    contain requested extras). Additional logic is added to also look up a value
+    by "cleaning up" the extras from the identifier.
+    """
+    if identifier in mapping:
+        return mapping[identifier]
+    # HACK: Theoretically we should check whether this identifier is a valid
+    # "NAME[EXTRAS]" format, and parse out the name part with packaging or
+    # some regular expression. But since pip's resolver only spits out three
+    # kinds of identifiers: normalized PEP 503 names, normalized names plus
+    # extras, and Requires-Python, we can cheat a bit here.
+    name, open_bracket, _ = identifier.partition("[")
+    if open_bracket and name in mapping:
+        return mapping[name]
+    return default
+
+
 class PipProvider(_ProviderBase):
     """Pip's provider implementation for resolvelib.
 
@@ -71,28 +109,44 @@ class PipProvider(_ProviderBase):
         identifier: str,
         resolutions: Mapping[str, Candidate],
         candidates: Mapping[str, Iterator[Candidate]],
-        information: Mapping[str, Iterator["PreferenceInformation"]],
+        information: Mapping[str, Iterable["PreferenceInformation"]],
+        backtrack_causes: Sequence["PreferenceInformation"],
     ) -> "Preference":
         """Produce a sort key for given requirement based on preference.
 
         The lower the return value is, the more preferred this group of
         arguments is.
 
-        Currently pip considers the followings in order:
+        Currently pip considers the following in order:
 
         * Prefer if any of the known requirements is "direct", e.g. points to an
           explicit URL.
         * If equal, prefer if any requirement is "pinned", i.e. contains
           operator ``===`` or ``==``.
         * If equal, calculate an approximate "depth" and resolve requirements
-          closer to the user-specified requirements first.
+          closer to the user-specified requirements first. If the depth cannot
+          by determined (eg: due to no matching parents), it is considered
+          infinite.
         * Order user-specified requirements by the order they are specified.
         * If equal, prefers "non-free" requirements, i.e. contains at least one
           operator, such as ``>=`` or ``<``.
         * If equal, order alphabetically for consistency (helps debuggability).
         """
-        lookups = (r.get_candidate_lookup() for r, _ in information[identifier])
-        candidate, ireqs = zip(*lookups)
+        try:
+            next(iter(information[identifier]))
+        except StopIteration:
+            # There is no information for this identifier, so there's no known
+            # candidates.
+            has_information = False
+        else:
+            has_information = True
+
+        if has_information:
+            lookups = (r.get_candidate_lookup() for r, _ in information[identifier])
+            candidate, ireqs = zip(*lookups)
+        else:
+            candidate, ireqs = None, ()
+
         operators = [
             specifier.operator
             for specifier_set in (ireq.specifier for ireq in ireqs if ireq)
@@ -107,14 +161,17 @@ class PipProvider(_ProviderBase):
             requested_order: Union[int, float] = self._user_requested[identifier]
         except KeyError:
             requested_order = math.inf
-            parent_depths = (
-                self._known_depths[parent.name] if parent is not None else 0.0
-                for _, parent in information[identifier]
-            )
-            inferred_depth = min(d for d in parent_depths) + 1.0
-            self._known_depths[identifier] = inferred_depth
+            if has_information:
+                parent_depths = (
+                    self._known_depths[parent.name] if parent is not None else 0.0
+                    for _, parent in information[identifier]
+                )
+                inferred_depth = min(d for d in parent_depths) + 1.0
+            else:
+                inferred_depth = math.inf
         else:
             inferred_depth = 1.0
+        self._known_depths[identifier] = inferred_depth
 
         requested_order = self._user_requested.get(identifier, math.inf)
 
@@ -122,49 +179,29 @@ class PipProvider(_ProviderBase):
         # free, so we always do it first to avoid needless work if it fails.
         requires_python = identifier == REQUIRES_PYTHON_IDENTIFIER
 
-        # HACK: Setuptools have a very long and solid backward compatibility
-        # track record, and extremely few projects would request a narrow,
-        # non-recent version range of it since that would break a lot things.
-        # (Most projects specify it only to request for an installer feature,
-        # which does not work, but that's another topic.) Intentionally
-        # delaying Setuptools helps reduce branches the resolver has to check.
-        # This serves as a temporary fix for issues like "apache-airlfow[all]"
-        # while we work on "proper" branch pruning techniques.
-        delay_this = identifier == "setuptools"
+        # Prefer the causes of backtracking on the assumption that the problem
+        # resolving the dependency tree is related to the failures that caused
+        # the backtracking
+        backtrack_cause = self.is_backtrack_cause(identifier, backtrack_causes)
 
         return (
             not requires_python,
-            delay_this,
             not direct,
             not pinned,
+            not backtrack_cause,
             inferred_depth,
             requested_order,
             not unfree,
             identifier,
         )
 
-    def _get_constraint(self, identifier: str) -> Constraint:
-        if identifier in self._constraints:
-            return self._constraints[identifier]
-
-        # HACK: Theoratically we should check whether this identifier is a valid
-        # "NAME[EXTRAS]" format, and parse out the name part with packaging or
-        # some regular expression. But since pip's resolver only spits out
-        # three kinds of identifiers: normalized PEP 503 names, normalized names
-        # plus extras, and Requires-Python, we can cheat a bit here.
-        name, open_bracket, _ = identifier.partition("[")
-        if open_bracket and name in self._constraints:
-            return self._constraints[name]
-
-        return Constraint.empty()
-
     def find_matches(
         self,
         identifier: str,
         requirements: Mapping[str, Iterator[Requirement]],
         incompatibilities: Mapping[str, Iterator[Candidate]],
     ) -> Iterable[Candidate]:
-        def _eligible_for_upgrade(name: str) -> bool:
+        def _eligible_for_upgrade(identifier: str) -> bool:
             """Are upgrades allowed for this project?
 
             This checks the upgrade strategy, and whether the project was one
@@ -178,13 +215,23 @@ class PipProvider(_ProviderBase):
             if self._upgrade_strategy == "eager":
                 return True
             elif self._upgrade_strategy == "only-if-needed":
-                return name in self._user_requested
+                user_order = _get_with_identifier(
+                    self._user_requested,
+                    identifier,
+                    default=None,
+                )
+                return user_order is not None
             return False
 
+        constraint = _get_with_identifier(
+            self._constraints,
+            identifier,
+            default=Constraint.empty(),
+        )
         return self._factory.find_candidates(
             identifier=identifier,
             requirements=requirements,
-            constraint=self._get_constraint(identifier),
+            constraint=constraint,
             prefers_installed=(not _eligible_for_upgrade(identifier)),
             incompatibilities=incompatibilities,
         )
@@ -195,3 +242,14 @@ class PipProvider(_ProviderBase):
     def get_dependencies(self, candidate: Candidate) -> Sequence[Requirement]:
         with_requires = not self._ignore_dependencies
         return [r for r in candidate.iter_dependencies(with_requires) if r is not None]
+
+    @staticmethod
+    def is_backtrack_cause(
+        identifier: str, backtrack_causes: Sequence["PreferenceInformation"]
+    ) -> bool:
+        for backtrack_cause in backtrack_causes:
+            if identifier == backtrack_cause.requirement.name:
+                return True
+            if backtrack_cause.parent and identifier == backtrack_cause.parent.name:
+                return True
+        return False

venv/Lib/site-packages/pip/_internal/resolution/resolvelib/reporter.py

@@ -11,9 +11,9 @@ logger = getLogger(__name__)
 
 class PipReporter(BaseReporter):
     def __init__(self) -> None:
-        self.backtracks_by_package: DefaultDict[str, int] = defaultdict(int)
+        self.reject_count_by_package: DefaultDict[str, int] = defaultdict(int)
 
-        self._messages_at_backtrack = {
+        self._messages_at_reject_count = {
             1: (
                 "pip is looking at multiple versions of {package_name} to "
                 "determine which version is compatible with other "
@@ -27,22 +27,33 @@ class PipReporter(BaseReporter):
             13: (
                 "This is taking longer than usual. You might need to provide "
                 "the dependency resolver with stricter constraints to reduce "
-                "runtime. If you want to abort this run, you can press "
-                "Ctrl + C to do so. To improve how pip performs, tell us what "
-                "happened here: https://pip.pypa.io/surveys/backtracking"
+                "runtime. See https://pip.pypa.io/warnings/backtracking for "
+                "guidance. If you want to abort this run, press Ctrl + C."
             ),
         }
 
-    def backtracking(self, candidate: Candidate) -> None:
-        self.backtracks_by_package[candidate.name] += 1
+    def rejecting_candidate(self, criterion: Any, candidate: Candidate) -> None:
+        self.reject_count_by_package[candidate.name] += 1
 
-        count = self.backtracks_by_package[candidate.name]
-        if count not in self._messages_at_backtrack:
+        count = self.reject_count_by_package[candidate.name]
+        if count not in self._messages_at_reject_count:
             return
 
-        message = self._messages_at_backtrack[count]
+        message = self._messages_at_reject_count[count]
         logger.info("INFO: %s", message.format(package_name=candidate.name))
 
+        msg = "Will try a different candidate, due to conflict:"
+        for req_info in criterion.information:
+            req, parent = req_info.requirement, req_info.parent
+            # Inspired by Factory.get_installation_error
+            msg += "\n    "
+            if parent:
+                msg += f"{parent.name} {parent.version} depends on "
+            else:
+                msg += "The user requested "
+            msg += req.format_for_error()
+        logger.debug(msg)
+
 
 class PipDebuggingReporter(BaseReporter):
     """A reporter that does an info log for every event it sees."""
@@ -62,8 +73,8 @@ class PipDebuggingReporter(BaseReporter):
     def adding_requirement(self, requirement: Requirement, parent: Candidate) -> None:
         logger.info("Reporter.adding_requirement(%r, %r)", requirement, parent)
 
-    def backtracking(self, candidate: Candidate) -> None:
-        logger.info("Reporter.backtracking(%r)", candidate)
+    def rejecting_candidate(self, criterion: Any, candidate: Candidate) -> None:
+        logger.info("Reporter.rejecting_candidate(%r, %r)", criterion, candidate)
 
     def pinning(self, candidate: Candidate) -> None:
         logger.info("Reporter.pinning(%r)", candidate)

venv/Lib/site-packages/pip/_internal/resolution/resolvelib/requirements.py

@@ -21,12 +21,12 @@ class ExplicitRequirement(Requirement):
 
     @property
     def project_name(self) -> NormalizedName:
-        # No need to canonicalise - the candidate did this
+        # No need to canonicalize - the candidate did this
         return self.candidate.project_name
 
     @property
     def name(self) -> str:
-        # No need to canonicalise - the candidate did this
+        # No need to canonicalize - the candidate did this
         return self.candidate.name
 
     def format_for_error(self) -> str:
@@ -64,7 +64,6 @@ class SpecifierRequirement(Requirement):
         return format_name(self.project_name, self._extras)
 
     def format_for_error(self) -> str:
-
         # Convert comma-separated specifiers into "A, B, ..., F and G"
         # This makes the specifier a bit more "human readable", without
         # risking a change in meaning. (Hopefully! Not all edge cases have

venv/Lib/site-packages/pip/_internal/resolution/resolvelib/resolver.py

@@ -19,8 +19,6 @@ from pip._internal.resolution.resolvelib.reporter import (
     PipDebuggingReporter,
     PipReporter,
 )
-from pip._internal.utils.deprecation import deprecated
-from pip._internal.utils.filetypes import is_archive_file
 
 from .base import Candidate, Requirement
 from .factory import Factory
@@ -90,9 +88,9 @@ class Resolver(BaseResolver):
         )
 
         try:
-            try_to_avoid_resolution_too_deep = 2000000
+            limit_how_complex_resolution_can_be = 200000
             result = self._result = resolver.resolve(
-                collected.requirements, max_rounds=try_to_avoid_resolution_too_deep
+                collected.requirements, max_rounds=limit_how_complex_resolution_can_be
             )
 
         except ResolutionImpossible as e:
@@ -136,25 +134,6 @@ class Resolver(BaseResolver):
                     )
                     continue
 
-                looks_like_sdist = (
-                    is_archive_file(candidate.source_link.file_path)
-                    and candidate.source_link.ext != ".zip"
-                )
-                if looks_like_sdist:
-                    # is a local sdist -- show a deprecation warning!
-                    reason = (
-                        "Source distribution is being reinstalled despite an "
-                        "installed package having the same name and version as "
-                        "the installed package."
-                    )
-                    replacement = "use --force-reinstall"
-                    deprecated(
-                        reason=reason,
-                        replacement=replacement,
-                        gone_in="21.3",
-                        issue=8711,
-                    )
-
                 # is a local sdist or path -- reinstall
                 ireq.should_reinstall = True
             else:
@@ -192,17 +171,19 @@ class Resolver(BaseResolver):
         get installed one-by-one.
 
         The current implementation creates a topological ordering of the
-        dependency graph, while breaking any cycles in the graph at arbitrary
-        points. We make no guarantees about where the cycle would be broken,
-        other than they would be broken.
+        dependency graph, giving more weight to packages with less
+        or no dependencies, while breaking any cycles in the graph at
+        arbitrary points. We make no guarantees about where the cycle
+        would be broken, other than it *would* be broken.
         """
         assert self._result is not None, "must call resolve() first"
 
+        if not req_set.requirements:
+            # Nothing is left to install, so we do not need an order.
+            return []
+
         graph = self._result.graph
-        weights = get_topological_weights(
-            graph,
-            expected_node_count=len(self._result.mapping) + 1,
-        )
+        weights = get_topological_weights(graph, set(req_set.requirements.keys()))
 
         sorted_items = sorted(
             req_set.requirements.items(),
@@ -213,23 +194,32 @@ class Resolver(BaseResolver):
 
 
 def get_topological_weights(
-    graph: "DirectedGraph[Optional[str]]", expected_node_count: int
+    graph: "DirectedGraph[Optional[str]]", requirement_keys: Set[str]
 ) -> Dict[Optional[str], int]:
     """Assign weights to each node based on how "deep" they are.
 
     This implementation may change at any point in the future without prior
     notice.
 
-    We take the length for the longest path to any node from root, ignoring any
-    paths that contain a single node twice (i.e. cycles). This is done through
-    a depth-first search through the graph, while keeping track of the path to
-    the node.
+    We first simplify the dependency graph by pruning any leaves and giving them
+    the highest weight: a package without any dependencies should be installed
+    first. This is done again and again in the same way, giving ever less weight
+    to the newly found leaves. The loop stops when no leaves are left: all
+    remaining packages have at least one dependency left in the graph.
+
+    Then we continue with the remaining graph, by taking the length for the
+    longest path to any node from root, ignoring any paths that contain a single
+    node twice (i.e. cycles). This is done through a depth-first search through
+    the graph, while keeping track of the path to the node.
 
     Cycles in the graph result would result in node being revisited while also
-    being it's own path. In this case, take no action. This helps ensure we
+    being on its own path. In this case, take no action. This helps ensure we
     don't get stuck in a cycle.
 
     When assigning weight, the longer path (i.e. larger length) is preferred.
+
+    We are only interested in the weights of packages that are in the
+    requirement_keys.
     """
     path: Set[Optional[str]] = set()
     weights: Dict[Optional[str], int] = {}
@@ -245,15 +235,49 @@ def get_topological_weights(
             visit(child)
         path.remove(node)
 
+        if node not in requirement_keys:
+            return
+
         last_known_parent_count = weights.get(node, 0)
         weights[node] = max(last_known_parent_count, len(path))
 
+    # Simplify the graph, pruning leaves that have no dependencies.
+    # This is needed for large graphs (say over 200 packages) because the
+    # `visit` function is exponentially slower then, taking minutes.
+    # See https://github.com/pypa/pip/issues/10557
+    # We will loop until we explicitly break the loop.
+    while True:
+        leaves = set()
+        for key in graph:
+            if key is None:
+                continue
+            for _child in graph.iter_children(key):
+                # This means we have at least one child
+                break
+            else:
+                # No child.
+                leaves.add(key)
+        if not leaves:
+            # We are done simplifying.
+            break
+        # Calculate the weight for the leaves.
+        weight = len(graph) - 1
+        for leaf in leaves:
+            if leaf not in requirement_keys:
+                continue
+            weights[leaf] = weight
+        # Remove the leaves from the graph, making it simpler.
+        for leaf in leaves:
+            graph.remove(leaf)
+
+    # Visit the remaining graph.
     # `None` is guaranteed to be the root node by resolvelib.
     visit(None)
 
-    # Sanity checks
-    assert weights[None] == 0
-    assert len(weights) == expected_node_count
+    # Sanity check: all requirement keys should be in the weights,
+    # and no other keys should be in the weights.
+    difference = set(weights.keys()).difference(requirement_keys)
+    assert not difference, difference
 
     return weights
 

venv/Lib/site-packages/pip/_internal/self_outdated_check.py

@@ -1,97 +1,149 @@
 import datetime
+import functools
 import hashlib
 import json
 import logging
 import optparse
 import os.path
 import sys
-from typing import Any, Dict
+from dataclasses import dataclass
+from typing import Any, Callable, Dict, Optional
 
 from pip._vendor.packaging.version import parse as parse_version
+from pip._vendor.rich.console import Group
+from pip._vendor.rich.markup import escape
+from pip._vendor.rich.text import Text
 
 from pip._internal.index.collector import LinkCollector
 from pip._internal.index.package_finder import PackageFinder
 from pip._internal.metadata import get_default_environment
+from pip._internal.metadata.base import DistributionVersion
 from pip._internal.models.selection_prefs import SelectionPreferences
 from pip._internal.network.session import PipSession
+from pip._internal.utils.compat import WINDOWS
+from pip._internal.utils.entrypoints import (
+    get_best_invocation_for_this_pip,
+    get_best_invocation_for_this_python,
+)
 from pip._internal.utils.filesystem import adjacent_tmp_file, check_path_owner, replace
 from pip._internal.utils.misc import ensure_dir
 
-SELFCHECK_DATE_FMT = "%Y-%m-%dT%H:%M:%SZ"
+_DATE_FMT = "%Y-%m-%dT%H:%M:%SZ"
 
 
 logger = logging.getLogger(__name__)
 
 
-def _get_statefile_name(key):
-    # type: (str) -> str
+def _get_statefile_name(key: str) -> str:
     key_bytes = key.encode()
     name = hashlib.sha224(key_bytes).hexdigest()
     return name
 
 
 class SelfCheckState:
-    def __init__(self, cache_dir):
-        # type: (str) -> None
-        self.state = {}  # type: Dict[str, Any]
-        self.statefile_path = None
+    def __init__(self, cache_dir: str) -> None:
+        self._state: Dict[str, Any] = {}
+        self._statefile_path = None
 
         # Try to load the existing state
         if cache_dir:
-            self.statefile_path = os.path.join(
+            self._statefile_path = os.path.join(
                 cache_dir, "selfcheck", _get_statefile_name(self.key)
             )
             try:
-                with open(self.statefile_path, encoding="utf-8") as statefile:
-                    self.state = json.load(statefile)
+                with open(self._statefile_path, encoding="utf-8") as statefile:
+                    self._state = json.load(statefile)
             except (OSError, ValueError, KeyError):
                 # Explicitly suppressing exceptions, since we don't want to
                 # error out if the cache file is invalid.
                 pass
 
     @property
-    def key(self):
-        # type: () -> str
+    def key(self) -> str:
         return sys.prefix
 
-    def save(self, pypi_version, current_time):
-        # type: (str, datetime.datetime) -> None
+    def get(self, current_time: datetime.datetime) -> Optional[str]:
+        """Check if we have a not-outdated version loaded already."""
+        if not self._state:
+            return None
+
+        if "last_check" not in self._state:
+            return None
+
+        if "pypi_version" not in self._state:
+            return None
+
+        seven_days_in_seconds = 7 * 24 * 60 * 60
+
+        # Determine if we need to refresh the state
+        last_check = datetime.datetime.strptime(self._state["last_check"], _DATE_FMT)
+        seconds_since_last_check = (current_time - last_check).total_seconds()
+        if seconds_since_last_check > seven_days_in_seconds:
+            return None
+
+        return self._state["pypi_version"]
+
+    def set(self, pypi_version: str, current_time: datetime.datetime) -> None:
         # If we do not have a path to cache in, don't bother saving.
-        if not self.statefile_path:
+        if not self._statefile_path:
             return
 
         # Check to make sure that we own the directory
-        if not check_path_owner(os.path.dirname(self.statefile_path)):
+        if not check_path_owner(os.path.dirname(self._statefile_path)):
             return
 
         # Now that we've ensured the directory is owned by this user, we'll go
         # ahead and make sure that all our directories are created.
-        ensure_dir(os.path.dirname(self.statefile_path))
+        ensure_dir(os.path.dirname(self._statefile_path))
 
         state = {
             # Include the key so it's easy to tell which pip wrote the
             # file.
             "key": self.key,
-            "last_check": current_time.strftime(SELFCHECK_DATE_FMT),
+            "last_check": current_time.strftime(_DATE_FMT),
             "pypi_version": pypi_version,
         }
 
         text = json.dumps(state, sort_keys=True, separators=(",", ":"))
 
-        with adjacent_tmp_file(self.statefile_path) as f:
+        with adjacent_tmp_file(self._statefile_path) as f:
             f.write(text.encode())
 
         try:
             # Since we have a prefix-specific state file, we can just
             # overwrite whatever is there, no need to check.
-            replace(f.name, self.statefile_path)
+            replace(f.name, self._statefile_path)
         except OSError:
             # Best effort.
             pass
 
 
-def was_installed_by_pip(pkg):
-    # type: (str) -> bool
+@dataclass
+class UpgradePrompt:
+    old: str
+    new: str
+
+    def __rich__(self) -> Group:
+        if WINDOWS:
+            pip_cmd = f"{get_best_invocation_for_this_python()} -m pip"
+        else:
+            pip_cmd = get_best_invocation_for_this_pip()
+
+        notice = "[bold][[reset][blue]notice[reset][bold]][reset]"
+        return Group(
+            Text(),
+            Text.from_markup(
+                f"{notice} A new release of pip is available: "
+                f"[red]{self.old}[reset] -> [green]{self.new}[reset]"
+            ),
+            Text.from_markup(
+                f"{notice} To update, run: "
+                f"[green]{escape(pip_cmd)} install --upgrade pip"
+            ),
+        )
+
+
+def was_installed_by_pip(pkg: str) -> bool:
     """Checks whether pkg was installed by pip
 
     This is used not to display the upgrade message when pip is in fact
@@ -101,8 +153,69 @@ def was_installed_by_pip(pkg):
     return dist is not None and "pip" == dist.installer
 
 
-def pip_self_version_check(session, options):
-    # type: (PipSession, optparse.Values) -> None
+def _get_current_remote_pip_version(
+    session: PipSession, options: optparse.Values
+) -> Optional[str]:
+    # Lets use PackageFinder to see what the latest pip version is
+    link_collector = LinkCollector.create(
+        session,
+        options=options,
+        suppress_no_index=True,
+    )
+
+    # Pass allow_yanked=False so we don't suggest upgrading to a
+    # yanked version.
+    selection_prefs = SelectionPreferences(
+        allow_yanked=False,
+        allow_all_prereleases=False,  # Explicitly set to False
+    )
+
+    finder = PackageFinder.create(
+        link_collector=link_collector,
+        selection_prefs=selection_prefs,
+    )
+    best_candidate = finder.find_best_candidate("pip").best_candidate
+    if best_candidate is None:
+        return None
+
+    return str(best_candidate.version)
+
+
+def _self_version_check_logic(
+    *,
+    state: SelfCheckState,
+    current_time: datetime.datetime,
+    local_version: DistributionVersion,
+    get_remote_version: Callable[[], Optional[str]],
+) -> Optional[UpgradePrompt]:
+    remote_version_str = state.get(current_time)
+    if remote_version_str is None:
+        remote_version_str = get_remote_version()
+        if remote_version_str is None:
+            logger.debug("No remote pip version found")
+            return None
+        state.set(remote_version_str, current_time)
+
+    remote_version = parse_version(remote_version_str)
+    logger.debug("Remote version of pip: %s", remote_version)
+    logger.debug("Local version of pip:  %s", local_version)
+
+    pip_installed_by_pip = was_installed_by_pip("pip")
+    logger.debug("Was pip installed by pip? %s", pip_installed_by_pip)
+    if not pip_installed_by_pip:
+        return None  # Only suggest upgrade if pip is installed by pip.
+
+    local_version_is_older = (
+        local_version < remote_version
+        and local_version.base_version != remote_version.base_version
+    )
+    if local_version_is_older:
+        return UpgradePrompt(old=str(local_version), new=remote_version_str)
+
+    return None
+
+
+def pip_self_version_check(session: PipSession, options: optparse.Values) -> None:
     """Check for an update for pip.
 
     Limit the frequency of checks to once per week. State is stored either in
@@ -113,75 +226,17 @@ def pip_self_version_check(session, options):
     if not installed_dist:
         return
 
-    pip_version = installed_dist.version
-    pypi_version = None
-
     try:
-        state = SelfCheckState(cache_dir=options.cache_dir)
-
-        current_time = datetime.datetime.utcnow()
-        # Determine if we need to refresh the state
-        if "last_check" in state.state and "pypi_version" in state.state:
-            last_check = datetime.datetime.strptime(
-                state.state["last_check"],
-                SELFCHECK_DATE_FMT
-            )
-            if (current_time - last_check).total_seconds() < 7 * 24 * 60 * 60:
-                pypi_version = state.state["pypi_version"]
-
-        # Refresh the version if we need to or just see if we need to warn
-        if pypi_version is None:
-            # Lets use PackageFinder to see what the latest pip version is
-            link_collector = LinkCollector.create(
-                session,
-                options=options,
-                suppress_no_index=True,
-            )
-
-            # Pass allow_yanked=False so we don't suggest upgrading to a
-            # yanked version.
-            selection_prefs = SelectionPreferences(
-                allow_yanked=False,
-                allow_all_prereleases=False,  # Explicitly set to False
-            )
-
-            finder = PackageFinder.create(
-                link_collector=link_collector,
-                selection_prefs=selection_prefs,
-            )
-            best_candidate = finder.find_best_candidate("pip").best_candidate
-            if best_candidate is None:
-                return
-            pypi_version = str(best_candidate.version)
-
-            # save that we've performed a check
-            state.save(pypi_version, current_time)
-
-        remote_version = parse_version(pypi_version)
-
-        local_version_is_older = (
-            pip_version < remote_version and
-            pip_version.base_version != remote_version.base_version and
-            was_installed_by_pip('pip')
-        )
-
-        # Determine if our pypi_version is older
-        if not local_version_is_older:
-            return
-
-        # We cannot tell how the current pip is available in the current
-        # command context, so be pragmatic here and suggest the command
-        # that's always available. This does not accommodate spaces in
-        # `sys.executable`.
-        pip_cmd = f"{sys.executable} -m pip"
-        logger.warning(
-            "You are using pip version %s; however, version %s is "
-            "available.\nYou should consider upgrading via the "
-            "'%s install --upgrade pip' command.",
-            pip_version, pypi_version, pip_cmd
+        upgrade_prompt = _self_version_check_logic(
+            state=SelfCheckState(cache_dir=options.cache_dir),
+            current_time=datetime.datetime.utcnow(),
+            local_version=installed_dist.version,
+            get_remote_version=functools.partial(
+                _get_current_remote_pip_version, session, options
+            ),
         )
+        if upgrade_prompt is not None:
+            logger.warning("[present-rich] %s", upgrade_prompt)
     except Exception:
-        logger.debug(
-            "There was an error checking the latest version of pip",
-            exc_info=True,
-        )
+        logger.warning("There was an error checking the latest version of pip.")
+        logger.debug("See below for error", exc_info=True)

venv/Lib/site-packages/pip/_internal/utils/appdirs.py

@@ -7,29 +7,46 @@ and eventually drop this after all usages are changed.
 """
 
 import os
+import sys
 from typing import List
 
-from pip._vendor import appdirs as _appdirs
+from pip._vendor import platformdirs as _appdirs
 
 
 def user_cache_dir(appname: str) -> str:
     return _appdirs.user_cache_dir(appname, appauthor=False)
 
 
+def _macos_user_config_dir(appname: str, roaming: bool = True) -> str:
+    # Use ~/Application Support/pip, if the directory exists.
+    path = _appdirs.user_data_dir(appname, appauthor=False, roaming=roaming)
+    if os.path.isdir(path):
+        return path
+
+    # Use a Linux-like ~/.config/pip, by default.
+    linux_like_path = "~/.config/"
+    if appname:
+        linux_like_path = os.path.join(linux_like_path, appname)
+
+    return os.path.expanduser(linux_like_path)
+
+
 def user_config_dir(appname: str, roaming: bool = True) -> str:
-    path = _appdirs.user_config_dir(appname, appauthor=False, roaming=roaming)
-    if _appdirs.system == "darwin" and not os.path.isdir(path):
-        path = os.path.expanduser("~/.config/")
-        if appname:
-            path = os.path.join(path, appname)
-    return path
+    if sys.platform == "darwin":
+        return _macos_user_config_dir(appname, roaming)
+
+    return _appdirs.user_config_dir(appname, appauthor=False, roaming=roaming)
 
 
 # for the discussion regarding site_config_dir locations
 # see <https://github.com/pypa/pip/issues/1733>
 def site_config_dirs(appname: str) -> List[str]:
+    if sys.platform == "darwin":
+        return [_appdirs.site_data_dir(appname, appauthor=False, multipath=True)]
+
     dirval = _appdirs.site_config_dir(appname, appauthor=False, multipath=True)
-    if _appdirs.system not in ["win32", "darwin"]:
-        # always look in /etc directly as well
-        return dirval.split(os.pathsep) + ["/etc"]
-    return [dirval]
+    if sys.platform == "win32":
+        return [dirval]
+
+    # Unix-y system. Look in /etc as well.
+    return dirval.split(os.pathsep) + ["/etc"]

venv/Lib/site-packages/pip/_internal/utils/compatibility_tags.py

@@ -2,9 +2,10 @@
 """
 
 import re
-from typing import TYPE_CHECKING, List, Optional, Tuple
+from typing import List, Optional, Tuple
 
 from pip._vendor.packaging.tags import (
+    PythonVersion,
     Tag,
     compatible_tags,
     cpython_tags,
@@ -14,10 +15,6 @@ from pip._vendor.packaging.tags import (
     mac_platforms,
 )
 
-if TYPE_CHECKING:
-    from pip._vendor.packaging.tags import PythonVersion
-
-
 _osx_arch_pat = re.compile(r"(.+)_(\d+)_(\d+)_(.+)")
 
 
@@ -95,7 +92,7 @@ def _expand_allowed_platforms(platforms: Optional[List[str]]) -> Optional[List[s
     return result
 
 
-def _get_python_version(version: str) -> "PythonVersion":
+def _get_python_version(version: str) -> PythonVersion:
     if len(version) > 1:
         return int(version[0]), int(version[1:])
     else:
@@ -132,7 +129,7 @@ def get_supported(
     """
     supported: List[Tag] = []
 
-    python_version: Optional["PythonVersion"] = None
+    python_version: Optional[PythonVersion] = None
     if version is not None:
         python_version = _get_python_version(version)
 

venv/Lib/site-packages/pip/_internal/utils/deprecation.py

@@ -8,7 +8,7 @@ from typing import Any, Optional, TextIO, Type, Union
 
 from pip._vendor.packaging.version import parse
 
-from pip import __version__ as current_version
+from pip import __version__ as current_version  # NOTE: tests patch this name.
 
 DEPRECATION_MSG_PREFIX = "DEPRECATION: "
 
@@ -53,52 +53,68 @@ def install_warning_logger() -> None:
 
 
 def deprecated(
+    *,
     reason: str,
     replacement: Optional[str],
     gone_in: Optional[str],
+    feature_flag: Optional[str] = None,
     issue: Optional[int] = None,
 ) -> None:
     """Helper to deprecate existing functionality.
 
     reason:
         Textual reason shown to the user about why this functionality has
-        been deprecated.
+        been deprecated. Should be a complete sentence.
     replacement:
         Textual suggestion shown to the user about what alternative
         functionality they can use.
     gone_in:
         The version of pip does this functionality should get removed in.
-        Raises errors if pip's current version is greater than or equal to
+        Raises an error if pip's current version is greater than or equal to
         this.
+    feature_flag:
+        Command-line flag of the form --use-feature={feature_flag} for testing
+        upcoming functionality.
     issue:
         Issue number on the tracker that would serve as a useful place for
         users to find related discussion and provide feedback.
-
-    Always pass replacement, gone_in and issue as keyword arguments for clarity
-    at the call site.
     """
 
-    # Construct a nice message.
-    #   This is eagerly formatted as we want it to get logged as if someone
-    #   typed this entire message out.
-    sentences = [
-        (reason, DEPRECATION_MSG_PREFIX + "{}"),
-        (gone_in, "pip {} will remove support for this functionality."),
-        (replacement, "A possible replacement is {}."),
+    # Determine whether or not the feature is already gone in this version.
+    is_gone = gone_in is not None and parse(current_version) >= parse(gone_in)
+
+    message_parts = [
+        (reason, f"{DEPRECATION_MSG_PREFIX}{{}}"),
+        (
+            gone_in,
+            "pip {} will enforce this behaviour change."
+            if not is_gone
+            else "Since pip {}, this is no longer supported.",
+        ),
+        (
+            replacement,
+            "A possible replacement is {}.",
+        ),
+        (
+            feature_flag,
+            "You can use the flag --use-feature={} to test the upcoming behaviour."
+            if not is_gone
+            else None,
+        ),
         (
             issue,
-            (
-                "You can find discussion regarding this at "
-                "https://github.com/pypa/pip/issues/{}."
-            ),
+            "Discussion can be found at https://github.com/pypa/pip/issues/{}",
         ),
     ]
+
     message = " ".join(
-        template.format(val) for val, template in sentences if val is not None
+        format_str.format(value)
+        for value, format_str in message_parts
+        if format_str is not None and value is not None
     )
 
-    # Raise as an error if it has to be removed.
-    if gone_in is not None and parse(current_version) >= parse(gone_in):
+    # Raise as an error if this behaviour is deprecated.
+    if is_gone:
         raise PipDeprecationWarning(message)
 
     warnings.warn(message, category=PipDeprecationWarning, stacklevel=2)

venv/Lib/site-packages/pip/_internal/utils/direct_url_helpers.py

@@ -2,6 +2,7 @@ from typing import Optional
 
 from pip._internal.models.direct_url import ArchiveInfo, DirectUrl, DirInfo, VcsInfo
 from pip._internal.models.link import Link
+from pip._internal.utils.urls import path_to_url
 from pip._internal.vcs import vcs
 
 
@@ -28,6 +29,13 @@ def direct_url_as_pep440_direct_reference(direct_url: DirectUrl, name: str) -> s
     return requirement
 
 
+def direct_url_for_editable(source_dir: str) -> DirectUrl:
+    return DirectUrl(
+        url=path_to_url(source_dir),
+        info=DirInfo(editable=True),
+    )
+
+
 def direct_url_from_link(
     link: Link, source_dir: Optional[str] = None, link_is_in_wheel_cache: bool = False
 ) -> DirectUrl:

venv/Lib/site-packages/pip/_internal/utils/distutils_args.py

@@ -1,42 +0,0 @@
-from distutils.errors import DistutilsArgError
-from distutils.fancy_getopt import FancyGetopt
-from typing import Dict, List
-
-_options = [
-    ("exec-prefix=", None, ""),
-    ("home=", None, ""),
-    ("install-base=", None, ""),
-    ("install-data=", None, ""),
-    ("install-headers=", None, ""),
-    ("install-lib=", None, ""),
-    ("install-platlib=", None, ""),
-    ("install-purelib=", None, ""),
-    ("install-scripts=", None, ""),
-    ("prefix=", None, ""),
-    ("root=", None, ""),
-    ("user", None, ""),
-]
-
-
-# typeshed doesn't permit Tuple[str, None, str], see python/typeshed#3469.
-_distutils_getopt = FancyGetopt(_options)  # type: ignore
-
-
-def parse_distutils_args(args: List[str]) -> Dict[str, str]:
-    """Parse provided arguments, returning an object that has the
-    matched arguments.
-
-    Any unknown arguments are ignored.
-    """
-    result = {}
-    for arg in args:
-        try:
-            _, match = _distutils_getopt.getopt(args=[arg])
-        except DistutilsArgError:
-            # We don't care about any other options, which here may be
-            # considered unrecognized since our option list is not
-            # exhaustive.
-            pass
-        else:
-            result.update(match.__dict__)
-    return result

venv/Lib/site-packages/pip/_internal/utils/encoding.py

@@ -14,7 +14,7 @@ BOMS: List[Tuple[bytes, str]] = [
     (codecs.BOM_UTF32_LE, "utf-32-le"),
 ]
 
-ENCODING_RE = re.compile(br"coding[:=]\s*([-\w.]+)")
+ENCODING_RE = re.compile(rb"coding[:=]\s*([-\w.]+)")
 
 
 def auto_decode(data: bytes) -> str:

venv/Lib/site-packages/pip/_internal/utils/entrypoints.py

@@ -1,7 +1,23 @@
+import itertools
+import os
+import shutil
 import sys
 from typing import List, Optional
 
 from pip._internal.cli.main import main
+from pip._internal.utils.compat import WINDOWS
+
+_EXECUTABLE_NAMES = [
+    "pip",
+    f"pip{sys.version_info.major}",
+    f"pip{sys.version_info.major}.{sys.version_info.minor}",
+]
+if WINDOWS:
+    _allowed_extensions = {"", ".exe"}
+    _EXECUTABLE_NAMES = [
+        "".join(parts)
+        for parts in itertools.product(_EXECUTABLE_NAMES, _allowed_extensions)
+    ]
 
 
 def _wrapper(args: Optional[List[str]] = None) -> int:
@@ -25,3 +41,44 @@ def _wrapper(args: Optional[List[str]] = None) -> int:
         "running pip directly.\n"
     )
     return main(args)
+
+
+def get_best_invocation_for_this_pip() -> str:
+    """Try to figure out the best way to invoke pip in the current environment."""
+    binary_directory = "Scripts" if WINDOWS else "bin"
+    binary_prefix = os.path.join(sys.prefix, binary_directory)
+
+    # Try to use pip[X[.Y]] names, if those executables for this environment are
+    # the first on PATH with that name.
+    path_parts = os.path.normcase(os.environ.get("PATH", "")).split(os.pathsep)
+    exe_are_in_PATH = os.path.normcase(binary_prefix) in path_parts
+    if exe_are_in_PATH:
+        for exe_name in _EXECUTABLE_NAMES:
+            found_executable = shutil.which(exe_name)
+            binary_executable = os.path.join(binary_prefix, exe_name)
+            if (
+                found_executable
+                and os.path.exists(binary_executable)
+                and os.path.samefile(
+                    found_executable,
+                    binary_executable,
+                )
+            ):
+                return exe_name
+
+    # Use the `-m` invocation, if there's no "nice" invocation.
+    return f"{get_best_invocation_for_this_python()} -m pip"
+
+
+def get_best_invocation_for_this_python() -> str:
+    """Try to figure out the best way to invoke the current Python."""
+    exe = sys.executable
+    exe_name = os.path.basename(exe)
+
+    # Try to use the basename, if it's the first executable.
+    found_executable = shutil.which(exe_name)
+    if found_executable and os.path.samefile(found_executable, exe):
+        return exe_name
+
+    # Use the full executable name, because we couldn't find something simpler.
+    return exe

venv/Lib/site-packages/pip/_internal/utils/filesystem.py

@@ -2,12 +2,10 @@ import fnmatch
 import os
 import os.path
 import random
-import shutil
-import stat
 import sys
 from contextlib import contextmanager
 from tempfile import NamedTemporaryFile
-from typing import Any, BinaryIO, Iterator, List, Union, cast
+from typing import Any, BinaryIO, Generator, List, Union, cast
 
 from pip._vendor.tenacity import retry, stop_after_delay, wait_fixed
 
@@ -42,35 +40,8 @@ def check_path_owner(path: str) -> bool:
     return False  # assume we don't own the path
 
 
-def copy2_fixed(src: str, dest: str) -> None:
-    """Wrap shutil.copy2() but map errors copying socket files to
-    SpecialFileError as expected.
-
-    See also https://bugs.python.org/issue37700.
-    """
-    try:
-        shutil.copy2(src, dest)
-    except OSError:
-        for f in [src, dest]:
-            try:
-                is_socket_file = is_socket(f)
-            except OSError:
-                # An error has already occurred. Another error here is not
-                # a problem and we can ignore it.
-                pass
-            else:
-                if is_socket_file:
-                    raise shutil.SpecialFileError(f"`{f}` is a socket")
-
-        raise
-
-
-def is_socket(path: str) -> bool:
-    return stat.S_ISSOCK(os.lstat(path).st_mode)
-
-
 @contextmanager
-def adjacent_tmp_file(path: str, **kwargs: Any) -> Iterator[BinaryIO]:
+def adjacent_tmp_file(path: str, **kwargs: Any) -> Generator[BinaryIO, None, None]:
     """Return a file-like object pointing to a tmp file next to path.
 
     The file is created securely and is ensured to be written to disk