Initial commit. Basic models mostly done.

venv/lib/python3.8/site-packages/pip/_internal/__init__.py

@@ -0,0 +1,18 @@
+#!/usr/bin/env python
+import pip._internal.utils.inject_securetransport  # noqa
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Optional, List
+
+
+def main(args=None):
+    # type: (Optional[List[str]]) -> int
+    """This is preserved for old console scripts that may still be referencing
+    it.
+
+    For additional details, see https://github.com/pypa/pip/issues/7498.
+    """
+    from pip._internal.utils.entrypoints import _wrapper
+
+    return _wrapper(args)

venv/lib/python3.8/site-packages/pip/_internal/build_env.py

@@ -0,0 +1,221 @@
+"""Build Environment used for isolation during sdist building
+"""
+
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+# mypy: disallow-untyped-defs=False
+
+import logging
+import os
+import sys
+import textwrap
+from collections import OrderedDict
+from distutils.sysconfig import get_python_lib
+from sysconfig import get_paths
+
+from pip._vendor.pkg_resources import Requirement, VersionConflict, WorkingSet
+
+from pip import __file__ as pip_location
+from pip._internal.utils.subprocess import call_subprocess
+from pip._internal.utils.temp_dir import TempDirectory
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.ui import open_spinner
+
+if MYPY_CHECK_RUNNING:
+    from typing import Tuple, Set, Iterable, Optional, List
+    from pip._internal.index.package_finder import PackageFinder
+
+logger = logging.getLogger(__name__)
+
+
+class _Prefix:
+
+    def __init__(self, path):
+        # type: (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']
+        # Note: prefer distutils' sysconfig to get the
+        # library paths so PyPy is correctly supported.
+        purelib = get_python_lib(plat_specific=False, prefix=path)
+        platlib = get_python_lib(plat_specific=True, prefix=path)
+        if purelib == platlib:
+            self.lib_dirs = [purelib]
+        else:
+            self.lib_dirs = [purelib, platlib]
+
+
+class BuildEnvironment(object):
+    """Creates and manages an isolated environment to install build deps
+    """
+
+    def __init__(self):
+        # type: () -> None
+        self._temp_dir = TempDirectory(kind="build-env")
+
+        self._prefixes = OrderedDict((
+            (name, _Prefix(os.path.join(self._temp_dir.path, name)))
+            for name in ('normal', 'overlay')
+        ))
+
+        self._bin_dirs = []  # type: List[str]
+        self._lib_dirs = []  # type: List[str]
+        for prefix in reversed(list(self._prefixes.values())):
+            self._bin_dirs.append(prefix.bin_dir)
+            self._lib_dirs.extend(prefix.lib_dirs)
+
+        # Customize site to:
+        # - ensure .pth files are honored
+        # - prevent access to system site packages
+        system_sites = {
+            os.path.normcase(site) for site in (
+                get_python_lib(plat_specific=False),
+                get_python_lib(plat_specific=True),
+            )
+        }
+        self._site_dir = os.path.join(self._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(
+                '''
+                import os, site, sys
+
+                # First, drop system-sites related paths.
+                original_sys_path = sys.path[:]
+                known_paths = set()
+                for path in {system_sites!r}:
+                    site.addsitedir(path, known_paths=known_paths)
+                system_paths = set(
+                    os.path.normcase(path)
+                    for path in sys.path[len(original_sys_path):]
+                )
+                original_sys_path = [
+                    path for path in original_sys_path
+                    if os.path.normcase(path) not in system_paths
+                ]
+                sys.path = original_sys_path
+
+                # Second, add lib directories.
+                # ensuring .pth file are processed.
+                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))
+
+    def __enter__(self):
+        self._save_env = {
+            name: os.environ.get(name, None)
+            for name in ('PATH', 'PYTHONNOUSERSITE', 'PYTHONPATH')
+        }
+
+        path = self._bin_dirs[:]
+        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),
+        })
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        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 cleanup(self):
+        # type: () -> None
+        self._temp_dir.cleanup()
+
+    def check_requirements(self, reqs):
+        # type: (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
+        """
+        missing = set()
+        conflicting = set()
+        if reqs:
+            ws = WorkingSet(self._lib_dirs)
+            for req in reqs:
+                try:
+                    if ws.find(Requirement.parse(req)) is None:
+                        missing.add(req)
+                except VersionConflict as e:
+                    conflicting.add((str(e.args[0].as_requirement()),
+                                     str(e.args[1])))
+        return conflicting, missing
+
+    def install_requirements(
+        self,
+        finder,  # type: PackageFinder
+        requirements,  # type: Iterable[str]
+        prefix_as_string,  # type: str
+        message  # type: Optional[str]
+    ):
+        # type: (...) -> None
+        prefix = self._prefixes[prefix_as_string]
+        assert not prefix.setup
+        prefix.setup = True
+        if not requirements:
+            return
+        args = [
+            sys.executable, os.path.dirname(pip_location), 'install',
+            '--ignore-installed', '--no-user', '--prefix', prefix.path,
+            '--no-warn-script-location',
+        ]  # type: List[str]
+        if logger.getEffectiveLevel() <= logging.DEBUG:
+            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:'}))))
+
+        index_urls = finder.index_urls
+        if index_urls:
+            args.extend(['-i', index_urls[0]])
+            for extra_index in index_urls[1:]:
+                args.extend(['--extra-index-url', extra_index])
+        else:
+            args.append('--no-index')
+        for link in finder.find_links:
+            args.extend(['--find-links', link])
+
+        for host in finder.trusted_hosts:
+            args.extend(['--trusted-host', host])
+        if finder.allow_all_prereleases:
+            args.append('--pre')
+        args.append('--')
+        args.extend(requirements)
+        with open_spinner(message) as spinner:
+            call_subprocess(args, spinner=spinner)
+
+
+class NoOpBuildEnvironment(BuildEnvironment):
+    """A no-op drop-in replacement for BuildEnvironment
+    """
+
+    def __init__(self):
+        pass
+
+    def __enter__(self):
+        pass
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        pass
+
+    def cleanup(self):
+        pass
+
+    def install_requirements(self, finder, requirements, prefix, message):
+        raise NotImplementedError()

venv/lib/python3.8/site-packages/pip/_internal/cache.py

@@ -0,0 +1,329 @@
+"""Cache Management
+"""
+
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+
+import hashlib
+import json
+import logging
+import os
+
+from pip._vendor.packaging.tags import interpreter_name, interpreter_version
+from pip._vendor.packaging.utils import canonicalize_name
+
+from pip._internal.exceptions import InvalidWheelFilename
+from pip._internal.models.link import Link
+from pip._internal.models.wheel import Wheel
+from pip._internal.utils.temp_dir import TempDirectory
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.urls import path_to_url
+
+if MYPY_CHECK_RUNNING:
+    from typing import Optional, Set, List, Any, Dict
+
+    from pip._vendor.packaging.tags import Tag
+
+    from pip._internal.models.format_control import FormatControl
+
+logger = logging.getLogger(__name__)
+
+
+def _hash_dict(d):
+    # type: (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()
+
+
+class Cache(object):
+    """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)
+    """
+
+    def __init__(self, cache_dir, format_control, allowed_formats):
+        # type: (str, FormatControl, Set[str]) -> None
+        super(Cache, self).__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_legacy(self, link):
+        # type: (Link) -> List[str]
+        """Get parts of part that must be os.path.joined with cache_dir
+
+        Legacy cache key (pip < 20) for compatibility with older caches.
+        """
+
+        # 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
+        # and we don't care about those.
+        key_parts = [link.url_without_fragment]
+        if link.hash_name is not None and link.hash is not None:
+            key_parts.append("=".join([link.hash_name, link.hash]))
+        key_url = "#".join(key_parts)
+
+        # Encode our key url with sha224, we'll use this because it has similar
+        # security properties to sha256, but with a shorter total output (and
+        # thus less secure). However the differences don't make a lot of
+        # difference for our use case here.
+        hashed = hashlib.sha224(key_url.encode()).hexdigest()
+
+        # We want to nest the directories some to prevent having a ton of top
+        # level directories where we might run out of sub directories on some
+        # FS.
+        parts = [hashed[:2], hashed[2:4], hashed[4:6], hashed[6:]]
+
+        return parts
+
+    def _get_cache_path_parts(self, link):
+        # type: (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
+        # and we don't care about those.
+        key_parts = {"url": link.url_without_fragment}
+        if link.hash_name is not None and link.hash is not None:
+            key_parts[link.hash_name] = link.hash
+        if link.subdirectory_fragment:
+            key_parts["subdirectory"] = link.subdirectory_fragment
+
+        # Include interpreter name, major and minor version in cache key
+        # to cope with ill-behaved sdists that build a different wheel
+        # depending on the python version their setup.py is being run on,
+        # and don't encode the difference in compatibility tags.
+        # https://github.com/pypa/pip/issues/7296
+        key_parts["interpreter_name"] = interpreter_name()
+        key_parts["interpreter_version"] = interpreter_version()
+
+        # Encode our key url with sha224, we'll use this because it has similar
+        # security properties to sha256, but with a shorter total output (and
+        # thus less secure). However the differences don't make a lot of
+        # difference for our use case here.
+        hashed = _hash_dict(key_parts)
+
+        # We want to nest the directories some to prevent having a ton of top
+        # level directories where we might run out of sub directories on some
+        # FS.
+        parts = [hashed[:2], hashed[2:4], hashed[4:6], hashed[6:]]
+
+        return parts
+
+    def _get_candidates(self, link, canonical_package_name):
+        # type: (Link, Optional[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):
+            for candidate in os.listdir(path):
+                candidates.append((candidate, path))
+        # TODO remove legacy path lookup in pip>=21
+        legacy_path = self.get_path_for_link_legacy(link)
+        if os.path.isdir(legacy_path):
+            for candidate in os.listdir(legacy_path):
+                candidates.append((candidate, legacy_path))
+        return candidates
+
+    def get_path_for_link_legacy(self, link):
+        # type: (Link) -> str
+        raise NotImplementedError()
+
+    def get_path_for_link(self, link):
+        # type: (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
+        """Returns a link to a cached item if it exists, otherwise returns the
+        passed link.
+        """
+        raise NotImplementedError()
+
+    def cleanup(self):
+        # type: () -> None
+        pass
+
+
+class SimpleWheelCache(Cache):
+    """A cache of wheels for future installs.
+    """
+
+    def __init__(self, cache_dir, format_control):
+        # type: (str, FormatControl) -> None
+        super(SimpleWheelCache, self).__init__(
+            cache_dir, format_control, {"binary"}
+        )
+
+    def get_path_for_link_legacy(self, link):
+        # type: (Link) -> str
+        parts = self._get_cache_path_parts_legacy(link)
+        return os.path.join(self.cache_dir, "wheels", *parts)
+
+    def get_path_for_link(self, link):
+        # type: (Link) -> str
+        """Return a directory to store cached wheels for link
+
+        Because there are M wheels for any one sdist, we provide a directory
+        to cache them in, and then consult that directory when looking up
+        cache hits.
+
+        We only insert things into the cache if they have plausible version
+        numbers, so that we don't contaminate the cache with things that were
+        not unique. E.g. ./package might have dozens of installs done for it
+        and build a version of 0.0...and if we built and cached a wheel, we'd
+        end up using the same wheel even if the source has been edited.
+
+        :param link: The link of the sdist for which this will cache wheels.
+        """
+        parts = self._get_cache_path_parts(link)
+
+        # Store wheels within the root cache_dir
+        return os.path.join(self.cache_dir, "wheels", *parts)
+
+    def get(
+        self,
+        link,            # type: Link
+        package_name,    # type: Optional[str]
+        supported_tags,  # type: List[Tag]
+    ):
+        # type: (...) -> 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
+        ):
+            try:
+                wheel = Wheel(wheel_name)
+            except InvalidWheelFilename:
+                continue
+            if canonicalize_name(wheel.name) != canonical_package_name:
+                logger.debug(
+                    "Ignoring cached wheel {} for {} as it "
+                    "does not match the expected distribution name {}.".format(
+                        wheel_name, link, package_name
+                    )
+                )
+                continue
+            if not wheel.supported(supported_tags):
+                # Built for a different python/arch/etc
+                continue
+            candidates.append(
+                (
+                    wheel.support_index_min(supported_tags),
+                    wheel_name,
+                    wheel_dir,
+                )
+            )
+
+        if not candidates:
+            return link
+
+        _, wheel_name, wheel_dir = min(candidates)
+        return Link(path_to_url(os.path.join(wheel_dir, wheel_name)))
+
+
+class EphemWheelCache(SimpleWheelCache):
+    """A SimpleWheelCache that creates it's own temporary cache directory
+    """
+
+    def __init__(self, format_control):
+        # type: (FormatControl) -> None
+        self._temp_dir = TempDirectory(kind="ephem-wheel-cache")
+
+        super(EphemWheelCache, self).__init__(
+            self._temp_dir.path, format_control
+        )
+
+    def cleanup(self):
+        # type: () -> None
+        self._temp_dir.cleanup()
+
+
+class WheelCache(Cache):
+    """Wraps EphemWheelCache and SimpleWheelCache into a single Cache
+
+    This Cache allows for gracefully degradation, using the ephem wheel 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(WheelCache, self).__init__(
+            cache_dir, format_control, {'binary'}
+        )
+        self._wheel_cache = SimpleWheelCache(cache_dir, format_control)
+        self._ephem_cache = EphemWheelCache(format_control)
+
+    def get_path_for_link_legacy(self, link):
+        # type: (Link) -> str
+        return self._wheel_cache.get_path_for_link_legacy(link)
+
+    def get_path_for_link(self, link):
+        # type: (Link) -> str
+        return self._wheel_cache.get_path_for_link(link)
+
+    def get_ephem_path_for_link(self, link):
+        # type: (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
+        retval = self._wheel_cache.get(
+            link=link,
+            package_name=package_name,
+            supported_tags=supported_tags,
+        )
+        if retval is not link:
+            return retval
+
+        return self._ephem_cache.get(
+            link=link,
+            package_name=package_name,
+            supported_tags=supported_tags,
+        )
+
+    def cleanup(self):
+        # type: () -> None
+        self._wheel_cache.cleanup()
+        self._ephem_cache.cleanup()

venv/lib/python3.8/site-packages/pip/_internal/cli/__init__.py

@@ -0,0 +1,4 @@
+"""Subpackage containing all of pip's command line interface related code
+"""
+
+# This file intentionally does not import submodules

venv/lib/python3.8/site-packages/pip/_internal/cli/autocompletion.py

@@ -0,0 +1,164 @@
+"""Logic that powers autocompletion installed by ``pip completion``.
+"""
+
+import optparse
+import os
+import sys
+from itertools import chain
+
+from pip._internal.cli.main_parser import create_main_parser
+from pip._internal.commands import commands_dict, create_command
+from pip._internal.utils.misc import get_installed_distributions
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Any, Iterable, List, Optional
+
+
+def autocomplete():
+    # type: () -> None
+    """Entry Point for completion of main and subcommand options.
+    """
+    # Don't complete if user hasn't sourced bash_completion file.
+    if 'PIP_AUTO_COMPLETE' not in os.environ:
+        return
+    cwords = os.environ['COMP_WORDS'].split()[1:]
+    cword = int(os.environ['COMP_CWORD'])
+    try:
+        current = cwords[cword - 1]
+    except IndexError:
+        current = ''
+
+    parser = create_main_parser()
+    subcommands = list(commands_dict)
+    options = []
+
+    # subcommand
+    subcommand_name = None  # type: Optional[str]
+    for word in cwords:
+        if word in subcommands:
+            subcommand_name = word
+            break
+    # subcommand options
+    if subcommand_name is not None:
+        # special case: 'help' subcommand has no options
+        if subcommand_name == 'help':
+            sys.exit(1)
+        # special case: list locally installed dists for show and uninstall
+        should_list_installed = (
+            subcommand_name in ['show', 'uninstall'] and
+            not current.startswith('-')
+        )
+        if should_list_installed:
+            installed = []
+            lc = current.lower()
+            for dist in get_installed_distributions(local_only=True):
+                if dist.key.startswith(lc) and dist.key not in cwords[1:]:
+                    installed.append(dist.key)
+            # if there are no dists installed, fall back to option completion
+            if installed:
+                for dist in installed:
+                    print(dist)
+                sys.exit(1)
+
+        subcommand = create_command(subcommand_name)
+
+        for opt in subcommand.parser.option_list_all:
+            if opt.help != optparse.SUPPRESS_HELP:
+                for opt_str in opt._long_opts + opt._short_opts:
+                    options.append((opt_str, opt.nargs))
+
+        # filter out previously specified options from available options
+        prev_opts = [x.split('=')[0] for x in cwords[1:cword - 1]]
+        options = [(x, v) for (x, v) in options if x not in prev_opts]
+        # filter options by current input
+        options = [(k, v) for k, v in options if k.startswith(current)]
+        # get completion type given cwords and available subcommand options
+        completion_type = get_path_completion_type(
+            cwords, cword, subcommand.parser.option_list_all,
+        )
+        # get completion files and directories if ``completion_type`` is
+        # ``<file>``, ``<dir>`` or ``<path>``
+        if completion_type:
+            paths = auto_complete_paths(current, completion_type)
+            options = [(path, 0) for path in paths]
+        for option in options:
+            opt_label = option[0]
+            # append '=' to options which require args
+            if option[1] and option[0][:2] == "--":
+                opt_label += '='
+            print(opt_label)
+    else:
+        # show main parser options only when necessary
+
+        opts = [i.option_list for i in parser.option_groups]
+        opts.append(parser.option_list)
+        flattened_opts = chain.from_iterable(opts)
+        if current.startswith('-'):
+            for opt in flattened_opts:
+                if opt.help != optparse.SUPPRESS_HELP:
+                    subcommands += opt._long_opts + opt._short_opts
+        else:
+            # get completion type given cwords and all available options
+            completion_type = get_path_completion_type(cwords, cword,
+                                                       flattened_opts)
+            if completion_type:
+                subcommands = list(auto_complete_paths(current,
+                                                       completion_type))
+
+        print(' '.join([x for x in subcommands if x.startswith(current)]))
+    sys.exit(1)
+
+
+def get_path_completion_type(cwords, cword, opts):
+    # type: (List[str], int, Iterable[Any]) -> Optional[str]
+    """Get the type of path completion (``file``, ``dir``, ``path`` or None)
+
+    :param cwords: same as the environmental variable ``COMP_WORDS``
+    :param cword: same as the environmental variable ``COMP_CWORD``
+    :param opts: The available options to check
+    :return: path completion type (``file``, ``dir``, ``path`` or None)
+    """
+    if cword < 2 or not cwords[cword - 2].startswith('-'):
+        return None
+    for opt in opts:
+        if opt.help == optparse.SUPPRESS_HELP:
+            continue
+        for o in str(opt).split('/'):
+            if cwords[cword - 2].split('=')[0] == o:
+                if not opt.metavar or any(
+                        x in ('path', 'file', 'dir')
+                        for x in opt.metavar.split('/')):
+                    return opt.metavar
+    return None
+
+
+def auto_complete_paths(current, completion_type):
+    # type: (str, str) -> Iterable[str]
+    """If ``completion_type`` is ``file`` or ``path``, list all regular files
+    and directories starting with ``current``; otherwise only list directories
+    starting with ``current``.
+
+    :param current: The word to be completed
+    :param completion_type: path completion type(`file`, `path` or `dir`)i
+    :return: A generator of regular files and/or directories
+    """
+    directory, filename = os.path.split(current)
+    current_path = os.path.abspath(directory)
+    # Don't complete paths if they can't be accessed
+    if not os.access(current_path, os.R_OK):
+        return
+    filename = os.path.normcase(filename)
+    # list all files that start with ``filename``
+    file_list = (x for x in os.listdir(current_path)
+                 if os.path.normcase(x).startswith(filename))
+    for f in file_list:
+        opt = os.path.join(current_path, f)
+        comp_file = os.path.normcase(os.path.join(directory, f))
+        # complete regular files when there is not ``<dir>`` after option
+        # complete directories when there is ``<file>``, ``<path>`` or
+        # ``<dir>``after option
+        if completion_type != 'dir' and os.path.isfile(opt):
+            yield comp_file
+        elif os.path.isdir(opt):
+            yield os.path.join(comp_file, '')

venv/lib/python3.8/site-packages/pip/_internal/cli/base_command.py

@@ -0,0 +1,226 @@
+"""Base Command class, and related routines"""
+
+from __future__ import absolute_import, print_function
+
+import logging
+import logging.config
+import optparse
+import os
+import platform
+import sys
+import traceback
+
+from pip._internal.cli import cmdoptions
+from pip._internal.cli.command_context import CommandContextMixIn
+from pip._internal.cli.parser import (
+    ConfigOptionParser,
+    UpdatingDefaultsHelpFormatter,
+)
+from pip._internal.cli.status_codes import (
+    ERROR,
+    PREVIOUS_BUILD_DIR_ERROR,
+    SUCCESS,
+    UNKNOWN_ERROR,
+    VIRTUALENV_NOT_FOUND,
+)
+from pip._internal.exceptions import (
+    BadCommand,
+    CommandError,
+    InstallationError,
+    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
+from pip._internal.utils.temp_dir import global_tempdir_manager
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.virtualenv import running_under_virtualenv
+
+if MYPY_CHECK_RUNNING:
+    from typing import List, Tuple, Any
+    from optparse import Values
+
+__all__ = ['Command']
+
+logger = logging.getLogger(__name__)
+
+
+class Command(CommandContextMixIn):
+    usage = None  # type: str
+    ignore_require_venv = False  # type: bool
+
+    def __init__(self, name, summary, isolated=False):
+        # type: (str, str, bool) -> None
+        super(Command, self).__init__()
+        parser_kw = {
+            'usage': self.usage,
+            'prog': '%s %s' % (get_prog(), name),
+            'formatter': UpdatingDefaultsHelpFormatter(),
+            'add_help_option': False,
+            'name': name,
+            'description': self.__doc__,
+            'isolated': isolated,
+        }
+
+        self.name = name
+        self.summary = summary
+        self.parser = ConfigOptionParser(**parser_kw)
+
+        # Commands should add options to this option group
+        optgroup_name = '%s Options' % self.name.capitalize()
+        self.cmd_opts = optparse.OptionGroup(self.parser, optgroup_name)
+
+        # Add the general options
+        gen_opts = cmdoptions.make_option_group(
+            cmdoptions.general_group,
+            self.parser,
+        )
+        self.parser.add_option_group(gen_opts)
+
+    def handle_pip_version_check(self, options):
+        # type: (Values) -> None
+        """
+        This is a no-op so that commands by default do not do the pip version
+        check.
+        """
+        # Make sure we do the pip version check if the index_group options
+        # are present.
+        assert not hasattr(options, 'no_index')
+
+    def run(self, options, args):
+        # type: (Values, List[Any]) -> Any
+        raise NotImplementedError
+
+    def parse_args(self, args):
+        # type: (List[str]) -> Tuple[Any, Any]
+        # factored out for testability
+        return self.parser.parse_args(args)
+
+    def main(self, args):
+        # type: (List[str]) -> int
+        try:
+            with self.main_context():
+                return self._main(args)
+        finally:
+            logging.shutdown()
+
+    def _main(self, args):
+        # type: (List[str]) -> int
+        # Intentionally set as early as possible so globally-managed temporary
+        # directories are available to the rest of the code.
+        self.enter_context(global_tempdir_manager())
+
+        options, args = self.parse_args(args)
+
+        # Set verbosity so that it can be used elsewhere.
+        self.verbosity = options.verbose - options.quiet
+
+        level_number = setup_logging(
+            verbosity=self.verbosity,
+            no_color=options.no_color,
+            user_log_file=options.log,
+        )
+
+        if (
+            sys.version_info[:2] == (2, 7) and
+            not options.no_python_version_warning
+        ):
+            message = (
+                "A future version of pip will drop support for Python 2.7. "
+                "More details about Python 2 support in pip, can be found at "
+                "https://pip.pypa.io/en/latest/development/release-process/#python-2-support"  # noqa
+            )
+            if platform.python_implementation() == "CPython":
+                message = (
+                    "Python 2.7 reached the end of its life on January "
+                    "1st, 2020. Please upgrade your Python as Python 2.7 "
+                    "is no longer maintained. "
+                ) + message
+            deprecated(message, replacement=None, gone_in=None)
+
+        if options.skip_requirements_regex:
+            deprecated(
+                "--skip-requirements-regex is unsupported and will be removed",
+                replacement=(
+                    "manage requirements/constraints files explicitly, "
+                    "possibly generating them from metadata"
+                ),
+                gone_in="20.1",
+                issue=7297,
+            )
+
+        # 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.
+
+        if options.no_input:
+            os.environ['PIP_NO_INPUT'] = '1'
+
+        if options.exists_action:
+            os.environ['PIP_EXISTS_ACTION'] = ' '.join(options.exists_action)
+
+        if options.require_venv and not self.ignore_require_venv:
+            # If a venv is required check if it can really be found
+            if not running_under_virtualenv():
+                logger.critical(
+                    'Could not find an activated virtualenv (required).'
+                )
+                sys.exit(VIRTUALENV_NOT_FOUND)
+
+        if options.cache_dir:
+            options.cache_dir = normalize_path(options.cache_dir)
+            if not check_path_owner(options.cache_dir):
+                logger.warning(
+                    "The directory '%s' or its parent directory is not owned "
+                    "or is not writable by the current user. The cache "
+                    "has been disabled. Check the permissions and owner of "
+                    "that directory. If executing pip with sudo, you may want "
+                    "sudo's -H flag.",
+                    options.cache_dir,
+                )
+                options.cache_dir = None
+
+        try:
+            status = self.run(options, args)
+            # FIXME: all commands should return an exit status
+            # and when it is done, isinstance is not needed anymore
+            if 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) 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
+        finally:
+            self.handle_pip_version_check(options)
+
+        return SUCCESS

venv/lib/python3.8/site-packages/pip/_internal/cli/cmdoptions.py

@@ -0,0 +1,957 @@
+"""
+shared options and groups
+
+The principle here is to define options once, but *not* instantiate them
+globally. One reason being that options with action='append' can carry state
+between parses. pip parses general options twice internally, and shouldn't
+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
+
+from __future__ import absolute_import
+
+import logging
+import os
+import textwrap
+import warnings
+from distutils.util import strtobool
+from functools import partial
+from optparse import SUPPRESS_HELP, Option, OptionGroup
+from textwrap import dedent
+
+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
+from pip._internal.models.index import PyPI
+from pip._internal.models.target_python import TargetPython
+from pip._internal.utils.hashes import STRONG_HASHES
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.ui import BAR_TYPES
+
+if MYPY_CHECK_RUNNING:
+    from typing import Any, Callable, Dict, Optional, Tuple
+    from optparse import OptionParser, Values
+    from pip._internal.cli.parser import ConfigOptionParser
+
+logger = logging.getLogger(__name__)
+
+
+def raise_option_error(parser, option, msg):
+    # type: (OptionParser, Option, str) -> None
+    """
+    Raise an option parsing error using parser.error().
+
+    Args:
+      parser: an OptionParser instance.
+      option: an Option instance.
+      msg: the error text.
+    """
+    msg = '{} error: {}'.format(option, msg)
+    msg = textwrap.fill(' '.join(msg.split()))
+    parser.error(msg)
+
+
+def make_option_group(group, parser):
+    # type: (Dict[str, Any], ConfigOptionParser) -> OptionGroup
+    """
+    Return an OptionGroup object
+    group  -- assumed to be dict with 'name' and 'options' keys
+    parser -- an optparse Parser
+    """
+    option_group = OptionGroup(parser, group['name'])
+    for option in group['options']:
+        option_group.add_option(option())
+    return option_group
+
+
+def check_install_build_global(options, check_options=None):
+    # type: (Values, Optional[Values]) -> 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):
+        # type: (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, check_target=False):
+    # type: (Values, bool) -> None
+    """Function for determining if custom platform options are allowed.
+
+    :param options: The OptionParser options.
+    :param check_target: Whether or not to check if --target is being used.
+    """
+    dist_restriction_set = any([
+        options.python_version,
+        options.platform,
+        options.abi,
+        options.implementation,
+    ])
+
+    binary_only = FormatControl(set(), {':all:'})
+    sdist_dependencies_allowed = (
+        options.format_control != binary_only and
+        not options.ignore_dependencies
+    )
+
+    # Installations or downloads using dist restrictions must not combine
+    # source distributions and dist-specific wheels, as they are not
+    # guaranteed to be locally compatible.
+    if dist_restriction_set and sdist_dependencies_allowed:
+        raise CommandError(
+            "When restricting platform and interpreter constraints using "
+            "--python-version, --platform, --abi, or --implementation, "
+            "either --no-deps must be set, or --only-binary=:all: must be "
+            "set and --no-binary must not be set (or must be set to "
+            ":none:)."
+        )
+
+    if check_target:
+        if dist_restriction_set and not options.target_dir:
+            raise CommandError(
+                "Can not use any platform or abi specific options unless "
+                "installing via '--target'"
+            )
+
+
+def _path_option_check(option, opt, value):
+    # type: (Option, str, str) -> str
+    return os.path.expanduser(value)
+
+
+class PipOption(Option):
+    TYPES = Option.TYPES + ("path",)
+    TYPE_CHECKER = Option.TYPE_CHECKER.copy()
+    TYPE_CHECKER["path"] = _path_option_check
+
+
+###########
+# options #
+###########
+
+help_ = partial(
+    Option,
+    '-h', '--help',
+    dest='help',
+    action='help',
+    help='Show help.',
+)  # type: Callable[..., Option]
+
+isolated_mode = partial(
+    Option,
+    "--isolated",
+    dest="isolated_mode",
+    action="store_true",
+    default=False,
+    help=(
+        "Run pip in an isolated mode, ignoring environment variables and user "
+        "configuration."
+    ),
+)  # type: Callable[..., Option]
+
+require_virtualenv = 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
+)  # type: Callable[..., Option]
+
+verbose = partial(
+    Option,
+    '-v', '--verbose',
+    dest='verbose',
+    action='count',
+    default=0,
+    help='Give more output. Option is additive, and can be used up to 3 times.'
+)  # type: Callable[..., Option]
+
+no_color = partial(
+    Option,
+    '--no-color',
+    dest='no_color',
+    action='store_true',
+    default=False,
+    help="Suppress colored output",
+)  # type: Callable[..., Option]
+
+version = partial(
+    Option,
+    '-V', '--version',
+    dest='version',
+    action='store_true',
+    help='Show version and exit.',
+)  # type: Callable[..., Option]
+
+quiet = partial(
+    Option,
+    '-q', '--quiet',
+    dest='quiet',
+    action='count',
+    default=0,
+    help=(
+        'Give less output. Option is additive, and can be used up to 3'
+        ' times (corresponding to WARNING, ERROR, and CRITICAL logging'
+        ' levels).'
+    ),
+)  # type: Callable[..., Option]
+
+progress_bar = partial(
+    Option,
+    '--progress-bar',
+    dest='progress_bar',
+    type='choice',
+    choices=list(BAR_TYPES.keys()),
+    default='on',
+    help=(
+        'Specify type of progress to be displayed [' +
+        '|'.join(BAR_TYPES.keys()) + '] (default: %default)'
+    ),
+)  # type: Callable[..., Option]
+
+log = partial(
+    PipOption,
+    "--log", "--log-file", "--local-log",
+    dest="log",
+    metavar="path",
+    type="path",
+    help="Path to a verbose appending log."
+)  # type: Callable[..., Option]
+
+no_input = partial(
+    Option,
+    # Don't ask for input
+    '--no-input',
+    dest='no_input',
+    action='store_true',
+    default=False,
+    help=SUPPRESS_HELP
+)  # type: Callable[..., Option]
+
+proxy = partial(
+    Option,
+    '--proxy',
+    dest='proxy',
+    type='str',
+    default='',
+    help="Specify a proxy in the form [user:passwd@]proxy.server:port."
+)  # type: Callable[..., Option]
+
+retries = partial(
+    Option,
+    '--retries',
+    dest='retries',
+    type='int',
+    default=5,
+    help="Maximum number of retries each connection should attempt "
+         "(default %default times).",
+)  # type: Callable[..., Option]
+
+timeout = partial(
+    Option,
+    '--timeout', '--default-timeout',
+    metavar='sec',
+    dest='timeout',
+    type='float',
+    default=15,
+    help='Set the socket timeout (default %default seconds).',
+)  # type: Callable[..., Option]
+
+skip_requirements_regex = partial(
+    Option,
+    # A regex to be used to skip requirements
+    '--skip-requirements-regex',
+    dest='skip_requirements_regex',
+    type='str',
+    default='',
+    help=SUPPRESS_HELP,
+)  # type: Callable[..., Option]
+
+
+def exists_action():
+    # type: () -> Option
+    return Option(
+        # Option when path already exist
+        '--exists-action',
+        dest='exists_action',
+        type='choice',
+        choices=['s', 'i', 'w', 'b', 'a'],
+        default=[],
+        action='append',
+        metavar='action',
+        help="Default action when a path already exists: "
+             "(s)witch, (i)gnore, (w)ipe, (b)ackup, (a)bort.",
+    )
+
+
+cert = partial(
+    PipOption,
+    '--cert',
+    dest='cert',
+    type='path',
+    metavar='path',
+    help="Path to alternate CA bundle.",
+)  # type: Callable[..., Option]
+
+client_cert = partial(
+    PipOption,
+    '--client-cert',
+    dest='client_cert',
+    type='path',
+    default=None,
+    metavar='path',
+    help="Path to SSL client certificate, a single file containing the "
+         "private key and the certificate in PEM format.",
+)  # type: Callable[..., Option]
+
+index_url = partial(
+    Option,
+    '-i', '--index-url', '--pypi-url',
+    dest='index_url',
+    metavar='URL',
+    default=PyPI.simple_url,
+    help="Base URL of the Python Package Index (default %default). "
+         "This should point to a repository compliant with PEP 503 "
+         "(the simple repository API) or a local directory laid out "
+         "in the same format.",
+)  # type: Callable[..., Option]
+
+
+def extra_index_url():
+    # type: () -> Option
+    return Option(
+        '--extra-index-url',
+        dest='extra_index_urls',
+        metavar='URL',
+        action='append',
+        default=[],
+        help="Extra URLs of package indexes to use in addition to "
+             "--index-url. Should follow the same rules as "
+             "--index-url.",
+    )
+
+
+no_index = partial(
+    Option,
+    '--no-index',
+    dest='no_index',
+    action='store_true',
+    default=False,
+    help='Ignore package index (only looking at --find-links URLs instead).',
+)  # type: Callable[..., Option]
+
+
+def find_links():
+    # type: () -> Option
+    return Option(
+        '-f', '--find-links',
+        dest='find_links',
+        action='append',
+        default=[],
+        metavar='url',
+        help="If a url or path to an html file, then parse for links to "
+             "archives. If a local path or file:// url that's a directory, "
+             "then look for archives in the directory listing.",
+    )
+
+
+def trusted_host():
+    # type: () -> Option
+    return Option(
+        "--trusted-host",
+        dest="trusted_hosts",
+        action="append",
+        metavar="HOSTNAME",
+        default=[],
+        help="Mark this host or host:port pair as trusted, even though it "
+             "does not have valid or any HTTPS.",
+    )
+
+
+def constraints():
+    # type: () -> Option
+    return Option(
+        '-c', '--constraint',
+        dest='constraints',
+        action='append',
+        default=[],
+        metavar='file',
+        help='Constrain versions using the given constraints file. '
+        'This option can be used multiple times.'
+    )
+
+
+def requirements():
+    # type: () -> Option
+    return Option(
+        '-r', '--requirement',
+        dest='requirements',
+        action='append',
+        default=[],
+        metavar='file',
+        help='Install from the given requirements file. '
+        'This option can be used multiple times.'
+    )
+
+
+def editable():
+    # type: () -> Option
+    return Option(
+        '-e', '--editable',
+        dest='editables',
+        action='append',
+        default=[],
+        metavar='path/url',
+        help=('Install a project in editable mode (i.e. setuptools '
+              '"develop mode") from a local project path or a VCS url.'),
+    )
+
+
+def _handle_src(option, opt_str, value, parser):
+    # type: (Option, str, str, OptionParser) -> None
+    value = os.path.abspath(value)
+    setattr(parser.values, option.dest, value)
+
+
+src = partial(
+    PipOption,
+    '--src', '--source', '--source-dir', '--source-directory',
+    dest='src_dir',
+    type='path',
+    metavar='dir',
+    default=get_src_prefix(),
+    action='callback',
+    callback=_handle_src,
+    help='Directory to check out editable projects into. '
+    'The default in a virtualenv is "<venv path>/src". '
+    'The default for global installs is "<current dir>/src".'
+)  # type: Callable[..., Option]
+
+
+def _get_format_control(values, option):
+    # type: (Values, Option) -> Any
+    """Get a format_control object."""
+    return getattr(values, option.dest)
+
+
+def _handle_no_binary(option, opt_str, value, parser):
+    # type: (Option, str, str, OptionParser) -> None
+    existing = _get_format_control(parser.values, option)
+    FormatControl.handle_mutual_excludes(
+        value, existing.no_binary, existing.only_binary,
+    )
+
+
+def _handle_only_binary(option, opt_str, value, parser):
+    # type: (Option, str, str, OptionParser) -> None
+    existing = _get_format_control(parser.values, option)
+    FormatControl.handle_mutual_excludes(
+        value, existing.only_binary, existing.no_binary,
+    )
+
+
+def no_binary():
+    # type: () -> Option
+    format_control = FormatControl(set(), set())
+    return Option(
+        "--no-binary", dest="format_control", action="callback",
+        callback=_handle_no_binary, type="str",
+        default=format_control,
+        help="Do not use binary packages. Can be supplied multiple times, and "
+             "each time adds to the existing value. Accepts either :all: to "
+             "disable all binary packages, :none: to empty the set, or one or "
+             "more package names with commas between them (no colons). Note "
+             "that some packages are tricky to compile and may fail to "
+             "install when this option is used on them.",
+    )
+
+
+def only_binary():
+    # type: () -> Option
+    format_control = FormatControl(set(), set())
+    return Option(
+        "--only-binary", dest="format_control", action="callback",
+        callback=_handle_only_binary, type="str",
+        default=format_control,
+        help="Do not use source packages. Can be supplied multiple times, and "
+             "each time adds to the existing value. Accepts either :all: to "
+             "disable all source packages, :none: to empty the set, or one or "
+             "more package names with commas between them. Packages without "
+             "binary distributions will fail to install when this option is "
+             "used on them.",
+    )
+
+
+platform = partial(
+    Option,
+    '--platform',
+    dest='platform',
+    metavar='platform',
+    default=None,
+    help=("Only use wheels compatible with <platform>. "
+          "Defaults to the platform of the running system."),
+)  # type: Callable[..., Option]
+
+
+# This was made a separate function for unit-testing purposes.
+def _convert_python_version(value):
+    # type: (str) -> Tuple[Tuple[int, ...], Optional[str]]
+    """
+    Convert a version string like "3", "37", or "3.7.3" into a tuple of ints.
+
+    :return: A 2-tuple (version_info, error_msg), where `error_msg` is
+        non-None if and only if there was a parsing error.
+    """
+    if not value:
+        # The empty string is the same as not providing a value.
+        return (None, None)
+
+    parts = value.split('.')
+    if len(parts) > 3:
+        return ((), 'at most three version parts are allowed')
+
+    if len(parts) == 1:
+        # Then we are in the case of "3" or "37".
+        value = parts[0]
+        if len(value) > 1:
+            parts = [value[0], value[1:]]
+
+    try:
+        version_info = tuple(int(part) for part in parts)
+    except ValueError:
+        return ((), 'each version part must be an integer')
+
+    return (version_info, None)
+
+
+def _handle_python_version(option, opt_str, value, parser):
+    # type: (Option, str, str, OptionParser) -> None
+    """
+    Handle a provided --python-version value.
+    """
+    version_info, error_msg = _convert_python_version(value)
+    if error_msg is not None:
+        msg = (
+            'invalid --python-version value: {!r}: {}'.format(
+                value, error_msg,
+            )
+        )
+        raise_option_error(parser, option=option, msg=msg)
+
+    parser.values.python_version = version_info
+
+
+python_version = partial(
+    Option,
+    '--python-version',
+    dest='python_version',
+    metavar='python_version',
+    action='callback',
+    callback=_handle_python_version, type='str',
+    default=None,
+    help=dedent("""\
+    The Python interpreter version to use for wheel and "Requires-Python"
+    compatibility checks. Defaults to a version derived from the running
+    interpreter. The version can be specified using up to three dot-separated
+    integers (e.g. "3" for 3.0.0, "3.7" for 3.7.0, or "3.7.3"). A major-minor
+    version can also be given as a string without dots (e.g. "37" for 3.7.0).
+    """),
+)  # type: Callable[..., Option]
+
+
+implementation = partial(
+    Option,
+    '--implementation',
+    dest='implementation',
+    metavar='implementation',
+    default=None,
+    help=("Only use wheels compatible with Python "
+          "implementation <implementation>, e.g. 'pp', 'jy', 'cp', "
+          " or 'ip'. If not specified, then the current "
+          "interpreter implementation is used.  Use 'py' to force "
+          "implementation-agnostic wheels."),
+)  # type: Callable[..., Option]
+
+
+abi = partial(
+    Option,
+    '--abi',
+    dest='abi',
+    metavar='abi',
+    default=None,
+    help=("Only use wheels compatible with Python "
+          "abi <abi>, e.g. 'pypy_41'.  If not specified, then the "
+          "current interpreter abi tag is used.  Generally "
+          "you will need to specify --implementation, "
+          "--platform, and --python-version when using "
+          "this option."),
+)  # type: Callable[..., Option]
+
+
+def add_target_python_options(cmd_opts):
+    # type: (OptionGroup) -> None
+    cmd_opts.add_option(platform())
+    cmd_opts.add_option(python_version())
+    cmd_opts.add_option(implementation())
+    cmd_opts.add_option(abi())
+
+
+def make_target_python(options):
+    # type: (Values) -> TargetPython
+    target_python = TargetPython(
+        platform=options.platform,
+        py_version_info=options.python_version,
+        abi=options.abi,
+        implementation=options.implementation,
+    )
+
+    return target_python
+
+
+def prefer_binary():
+    # type: () -> Option
+    return Option(
+        "--prefer-binary",
+        dest="prefer_binary",
+        action="store_true",
+        default=False,
+        help="Prefer older binary packages over newer source packages."
+    )
+
+
+cache_dir = partial(
+    PipOption,
+    "--cache-dir",
+    dest="cache_dir",
+    default=USER_CACHE_DIR,
+    metavar="dir",
+    type='path',
+    help="Store the cache data in <dir>."
+)  # type: Callable[..., Option]
+
+
+def _handle_no_cache_dir(option, opt, value, parser):
+    # type: (Option, str, str, OptionParser) -> None
+    """
+    Process a value provided for the --no-cache-dir option.
+
+    This is an optparse.Option callback for the --no-cache-dir option.
+    """
+    # The value argument will be None if --no-cache-dir is passed via the
+    # command-line, since the option doesn't accept arguments.  However,
+    # the value can be non-None if the option is triggered e.g. by an
+    # environment variable, like PIP_NO_CACHE_DIR=true.
+    if value is not None:
+        # Then parse the string value to get argument error-checking.
+        try:
+            strtobool(value)
+        except ValueError as exc:
+            raise_option_error(parser, option=option, msg=str(exc))
+
+    # Originally, setting PIP_NO_CACHE_DIR to a value that strtobool()
+    # converted to 0 (like "false" or "no") caused cache_dir to be disabled
+    # rather than enabled (logic would say the latter).  Thus, we disable
+    # the cache directory not just on values that parse to True, but (for
+    # backwards compatibility reasons) also on values that parse to False.
+    # In other words, always set it to False if the option is provided in
+    # some (valid) form.
+    parser.values.cache_dir = False
+
+
+no_cache = partial(
+    Option,
+    "--no-cache-dir",
+    dest="cache_dir",
+    action="callback",
+    callback=_handle_no_cache_dir,
+    help="Disable the cache.",
+)  # type: Callable[..., Option]
+
+no_deps = partial(
+    Option,
+    '--no-deps', '--no-dependencies',
+    dest='ignore_dependencies',
+    action='store_true',
+    default=False,
+    help="Don't install package dependencies.",
+)  # type: Callable[..., Option]
+
+
+def _handle_build_dir(option, opt, value, parser):
+    # type: (Option, str, str, OptionParser) -> None
+    if value:
+        value = os.path.abspath(value)
+    setattr(parser.values, option.dest, value)
+
+
+build_dir = partial(
+    PipOption,
+    '-b', '--build', '--build-dir', '--build-directory',
+    dest='build_dir',
+    type='path',
+    metavar='dir',
+    action='callback',
+    callback=_handle_build_dir,
+    help='Directory to unpack packages into and build in. Note that '
+         'an initial build still takes place in a temporary directory. '
+         'The location of temporary directories can be controlled by setting '
+         'the TMPDIR environment variable (TEMP on Windows) appropriately. '
+         'When passed, build directories are not cleaned in case of failures.'
+)  # type: Callable[..., Option]
+
+ignore_requires_python = partial(
+    Option,
+    '--ignore-requires-python',
+    dest='ignore_requires_python',
+    action='store_true',
+    help='Ignore the Requires-Python information.'
+)  # type: Callable[..., Option]
+
+no_build_isolation = partial(
+    Option,
+    '--no-build-isolation',
+    dest='build_isolation',
+    action='store_false',
+    default=True,
+    help='Disable isolation when building a modern source distribution. '
+         'Build dependencies specified by PEP 518 must be already installed '
+         'if this option is used.'
+)  # type: Callable[..., Option]
+
+
+def _handle_no_use_pep517(option, opt, value, parser):
+    # type: (Option, str, str, OptionParser) -> None
+    """
+    Process a value provided for the --no-use-pep517 option.
+
+    This is an optparse.Option callback for the no_use_pep517 option.
+    """
+    # Since --no-use-pep517 doesn't accept arguments, the value argument
+    # will be None if --no-use-pep517 is passed via the command-line.
+    # However, the value can be non-None if the option is triggered e.g.
+    # by an environment variable, for example "PIP_NO_USE_PEP517=true".
+    if value is not None:
+        msg = """A value was passed for --no-use-pep517,
+        probably using either the PIP_NO_USE_PEP517 environment variable
+        or the "no-use-pep517" config file option. Use an appropriate value
+        of the PIP_USE_PEP517 environment variable or the "use-pep517"
+        config file option instead.
+        """
+        raise_option_error(parser, option=option, msg=msg)
+
+    # Otherwise, --no-use-pep517 was passed via the command-line.
+    parser.values.use_pep517 = False
+
+
+use_pep517 = partial(
+    Option,
+    '--use-pep517',
+    dest='use_pep517',
+    action='store_true',
+    default=None,
+    help='Use PEP 517 for building source distributions '
+         '(use --no-use-pep517 to force legacy behaviour).'
+)  # type: Any
+
+no_use_pep517 = partial(
+    Option,
+    '--no-use-pep517',
+    dest='use_pep517',
+    action='callback',
+    callback=_handle_no_use_pep517,
+    default=None,
+    help=SUPPRESS_HELP
+)  # type: Any
+
+install_options = 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.",
+)  # type: Callable[..., Option]
+
+global_options = partial(
+    Option,
+    '--global-option',
+    dest='global_options',
+    action='append',
+    metavar='options',
+    help="Extra global options to be supplied to the setup.py "
+         "call before the install command.",
+)  # type: Callable[..., Option]
+
+no_clean = partial(
+    Option,
+    '--no-clean',
+    action='store_true',
+    default=False,
+    help="Don't clean up build directories."
+)  # type: Callable[..., Option]
+
+pre = partial(
+    Option,
+    '--pre',
+    action='store_true',
+    default=False,
+    help="Include pre-release and development versions. By default, "
+         "pip only finds stable versions.",
+)  # type: Callable[..., Option]
+
+disable_pip_version_check = partial(
+    Option,
+    "--disable-pip-version-check",
+    dest="disable_pip_version_check",
+    action="store_true",
+    default=False,
+    help="Don't periodically check PyPI to determine whether a new version "
+         "of pip is available for download. Implied with --no-index.",
+)  # type: Callable[..., Option]
+
+
+# Deprecated, Remove later
+always_unzip = partial(
+    Option,
+    '-Z', '--always-unzip',
+    dest='always_unzip',
+    action='store_true',
+    help=SUPPRESS_HELP,
+)  # type: Callable[..., Option]
+
+
+def _handle_merge_hash(option, opt_str, value, parser):
+    # type: (Option, str, str, OptionParser) -> None
+    """Given a value spelled "algo:digest", append the digest to a list
+    pointed to in a dict by the algo name."""
+    if not parser.values.hashes:
+        parser.values.hashes = {}
+    try:
+        algo, digest = value.split(':', 1)
+    except ValueError:
+        parser.error('Arguments to %s must be a hash name '
+                     'followed by a value, like --hash=sha256:abcde...' %
+                     opt_str)
+    if algo not in STRONG_HASHES:
+        parser.error('Allowed hash algorithms for %s are %s.' %
+                     (opt_str, ', '.join(STRONG_HASHES)))
+    parser.values.hashes.setdefault(algo, []).append(digest)
+
+
+hash = partial(
+    Option,
+    '--hash',
+    # Hash values eventually end up in InstallRequirement.hashes due to
+    # __dict__ copying in process_line().
+    dest='hashes',
+    action='callback',
+    callback=_handle_merge_hash,
+    type='string',
+    help="Verify that the package's archive matches this "
+         'hash before installing. Example: --hash=sha256:abcdef...',
+)  # type: Callable[..., Option]
+
+
+require_hashes = partial(
+    Option,
+    '--require-hashes',
+    dest='require_hashes',
+    action='store_true',
+    default=False,
+    help='Require a hash to check each requirement against, for '
+         'repeatable installs. This option is implied when any package in a '
+         'requirements file has a --hash option.',
+)  # type: Callable[..., Option]
+
+
+list_path = partial(
+    PipOption,
+    '--path',
+    dest='path',
+    type='path',
+    action='append',
+    help='Restrict to the specified installation path for listing '
+         'packages (can be used multiple times).'
+)  # type: Callable[..., Option]
+
+
+def check_list_path_option(options):
+    # type: (Values) -> None
+    if options.path and (options.user or options.local):
+        raise CommandError(
+            "Cannot combine '--path' with '--user' or '--local'"
+        )
+
+
+no_python_version_warning = partial(
+    Option,
+    '--no-python-version-warning',
+    dest='no_python_version_warning',
+    action='store_true',
+    default=False,
+    help='Silence deprecation warnings for upcoming unsupported Pythons.',
+)  # type: Callable[..., Option]
+
+
+##########
+# groups #
+##########
+
+general_group = {
+    'name': 'General Options',
+    'options': [
+        help_,
+        isolated_mode,
+        require_virtualenv,
+        verbose,
+        version,
+        quiet,
+        log,
+        no_input,
+        proxy,
+        retries,
+        timeout,
+        skip_requirements_regex,
+        exists_action,
+        trusted_host,
+        cert,
+        client_cert,
+        cache_dir,
+        no_cache,
+        disable_pip_version_check,
+        no_color,
+        no_python_version_warning,
+    ]
+}  # type: Dict[str, Any]
+
+index_group = {
+    'name': 'Package Index Options',
+    'options': [
+        index_url,
+        extra_index_url,
+        no_index,
+        find_links,
+    ]
+}  # type: Dict[str, Any]

venv/lib/python3.8/site-packages/pip/_internal/cli/command_context.py

@@ -0,0 +1,36 @@
+from contextlib import contextmanager
+
+from pip._vendor.contextlib2 import ExitStack
+
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Iterator, ContextManager, TypeVar
+
+    _T = TypeVar('_T', covariant=True)
+
+
+class CommandContextMixIn(object):
+    def __init__(self):
+        # type: () -> None
+        super(CommandContextMixIn, self).__init__()
+        self._in_main_context = False
+        self._main_context = ExitStack()
+
+    @contextmanager
+    def main_context(self):
+        # type: () -> Iterator[None]
+        assert not self._in_main_context
+
+        self._in_main_context = True
+        try:
+            with self._main_context:
+                yield
+        finally:
+            self._in_main_context = False
+
+    def enter_context(self, context_provider):
+        # type: (ContextManager[_T]) -> _T
+        assert self._in_main_context
+
+        return self._main_context.enter_context(context_provider)

venv/lib/python3.8/site-packages/pip/_internal/cli/main.py

@@ -0,0 +1,75 @@
+"""Primary application entrypoint.
+"""
+from __future__ import absolute_import
+
+import locale
+import logging
+import os
+import sys
+
+from pip._internal.cli.autocompletion import autocomplete
+from pip._internal.cli.main_parser import parse_command
+from pip._internal.commands import create_command
+from pip._internal.exceptions import PipError
+from pip._internal.utils import deprecation
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import List, Optional
+
+logger = logging.getLogger(__name__)
+
+
+# Do not import and use main() directly! Using it directly is actively
+# discouraged by pip's maintainers. The name, location and behavior of
+# this function is subject to change, so calling it directly is not
+# portable across different pip versions.
+
+# In addition, running pip in-process is unsupported and unsafe. This is
+# elaborated in detail at
+# https://pip.pypa.io/en/stable/user_guide/#using-pip-from-your-program.
+# That document also provides suggestions that should work for nearly
+# all users that are considering importing and using main() directly.
+
+# However, we know that certain users will still want to invoke pip
+# in-process. If you understand and accept the implications of using pip
+# in an unsupported manner, the best approach is to use runpy to avoid
+# depending on the exact location of this entry point.
+
+# The following example shows how to use runpy to invoke pip in that
+# case:
+#
+#     sys.argv = ["pip", your, args, here]
+#     runpy.run_module("pip", run_name="__main__")
+#
+# Note that this will exit the process after running, unlike a direct
+# call to main. As it is not safe to do any processing after calling
+# main, this should not be an issue in practice.
+
+def main(args=None):
+    # type: (Optional[List[str]]) -> int
+    if args is None:
+        args = sys.argv[1:]
+
+    # Configure our deprecation warnings to be sent through loggers
+    deprecation.install_warning_logger()
+
+    autocomplete()
+
+    try:
+        cmd_name, cmd_args = parse_command(args)
+    except PipError as exc:
+        sys.stderr.write("ERROR: %s" % exc)
+        sys.stderr.write(os.linesep)
+        sys.exit(1)
+
+    # Needed for locale.getpreferredencoding(False) to work
+    # in pip._internal.utils.encoding.auto_decode
+    try:
+        locale.setlocale(locale.LC_ALL, '')
+    except locale.Error as e:
+        # setlocale can apparently crash if locale are uninitialized
+        logger.debug("Ignoring error %s when setting locale", e)
+    command = create_command(cmd_name, isolated=("--isolated" in cmd_args))
+
+    return command.main(cmd_args)

venv/lib/python3.8/site-packages/pip/_internal/cli/main_parser.py

@@ -0,0 +1,99 @@
+"""A single place for constructing and exposing the main parser
+"""
+
+import os
+import sys
+
+from pip._internal.cli import cmdoptions
+from pip._internal.cli.parser import (
+    ConfigOptionParser,
+    UpdatingDefaultsHelpFormatter,
+)
+from pip._internal.commands import commands_dict, get_similar_commands
+from pip._internal.exceptions import CommandError
+from pip._internal.utils.misc import get_pip_version, get_prog
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Tuple, List
+
+
+__all__ = ["create_main_parser", "parse_command"]
+
+
+def create_main_parser():
+    # type: () -> ConfigOptionParser
+    """Creates and returns the main parser for pip's CLI
+    """
+
+    parser_kw = {
+        'usage': '\n%prog <command> [options]',
+        'add_help_option': False,
+        'formatter': UpdatingDefaultsHelpFormatter(),
+        'name': 'global',
+        'prog': get_prog(),
+    }
+
+    parser = ConfigOptionParser(**parser_kw)
+    parser.disable_interspersed_args()
+
+    parser.version = get_pip_version()
+
+    # add the general options
+    gen_opts = cmdoptions.make_option_group(cmdoptions.general_group, parser)
+    parser.add_option_group(gen_opts)
+
+    # so the help formatter knows
+    parser.main = True  # type: ignore
+
+    # create command listing for description
+    description = [''] + [
+        '%-27s %s' % (name, command_info.summary)
+        for name, command_info in commands_dict.items()
+    ]
+    parser.description = '\n'.join(description)
+
+    return parser
+
+
+def parse_command(args):
+    # type: (List[str]) -> Tuple[str, List[str]]
+    parser = create_main_parser()
+
+    # Note: parser calls disable_interspersed_args(), so the result of this
+    # call is to split the initial args into the general options before the
+    # subcommand and everything else.
+    # For example:
+    #  args: ['--timeout=5', 'install', '--user', 'INITools']
+    #  general_options: ['--timeout==5']
+    #  args_else: ['install', '--user', 'INITools']
+    general_options, args_else = parser.parse_args(args)
+
+    # --version
+    if general_options.version:
+        sys.stdout.write(parser.version)  # type: ignore
+        sys.stdout.write(os.linesep)
+        sys.exit()
+
+    # pip || pip help -> print_help()
+    if not args_else or (args_else[0] == 'help' and len(args_else) == 1):
+        parser.print_help()
+        sys.exit()
+
+    # the subcommand name
+    cmd_name = args_else[0]
+
+    if cmd_name not in commands_dict:
+        guess = get_similar_commands(cmd_name)
+
+        msg = ['unknown command "%s"' % cmd_name]
+        if guess:
+            msg.append('maybe you meant "%s"' % guess)
+
+        raise CommandError(' - '.join(msg))
+
+    # all the args without the subcommand
+    cmd_args = args[:]
+    cmd_args.remove(cmd_name)
+
+    return cmd_name, cmd_args

venv/lib/python3.8/site-packages/pip/_internal/cli/parser.py

@@ -0,0 +1,265 @@
+"""Base option parser setup"""
+
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import logging
+import optparse
+import sys
+import textwrap
+from distutils.util import strtobool
+
+from pip._vendor.six import string_types
+
+from pip._internal.cli.status_codes import UNKNOWN_ERROR
+from pip._internal.configuration import Configuration, ConfigurationError
+from pip._internal.utils.compat import get_terminal_size
+
+logger = logging.getLogger(__name__)
+
+
+class PrettyHelpFormatter(optparse.IndentedHelpFormatter):
+    """A prettier/less verbose help formatter for optparse."""
+
+    def __init__(self, *args, **kwargs):
+        # help position must be aligned with __init__.parseopts.description
+        kwargs['max_help_position'] = 30
+        kwargs['indent_increment'] = 1
+        kwargs['width'] = get_terminal_size()[0] - 2
+        optparse.IndentedHelpFormatter.__init__(self, *args, **kwargs)
+
+    def format_option_strings(self, option):
+        return self._format_option_strings(option, ' <%s>', ', ')
+
+    def _format_option_strings(self, option, mvarfmt=' <%s>', optsep=', '):
+        """
+        Return a comma-separated list of option strings and metavars.
+
+        :param option:  tuple of (short opt, long opt), e.g: ('-f', '--format')
+        :param mvarfmt: metavar format string - evaluated as mvarfmt % metavar
+        :param optsep:  separator
+        """
+        opts = []
+
+        if option._short_opts:
+            opts.append(option._short_opts[0])
+        if option._long_opts:
+            opts.append(option._long_opts[0])
+        if len(opts) > 1:
+            opts.insert(1, optsep)
+
+        if option.takes_value():
+            metavar = option.metavar or option.dest.lower()
+            opts.append(mvarfmt % metavar.lower())
+
+        return ''.join(opts)
+
+    def format_heading(self, heading):
+        if heading == 'Options':
+            return ''
+        return heading + ':\n'
+
+    def format_usage(self, usage):
+        """
+        Ensure there is only one newline between usage and the first heading
+        if there is no description.
+        """
+        msg = '\nUsage: %s\n' % self.indent_lines(textwrap.dedent(usage), "  ")
+        return msg
+
+    def format_description(self, description):
+        # leave full control over description to us
+        if description:
+            if hasattr(self.parser, 'main'):
+                label = 'Commands'
+            else:
+                label = 'Description'
+            # some doc strings have initial newlines, some don't
+            description = description.lstrip('\n')
+            # some doc strings have final newlines and spaces, some don't
+            description = description.rstrip()
+            # dedent, then reindent
+            description = self.indent_lines(textwrap.dedent(description), "  ")
+            description = '%s:\n%s\n' % (label, description)
+            return description
+        else:
+            return ''
+
+    def format_epilog(self, epilog):
+        # leave full control over epilog to us
+        if epilog:
+            return epilog
+        else:
+            return ''
+
+    def indent_lines(self, text, indent):
+        new_lines = [indent + line for line in text.split('\n')]
+        return "\n".join(new_lines)
+
+
+class UpdatingDefaultsHelpFormatter(PrettyHelpFormatter):
+    """Custom help formatter for use in ConfigOptionParser.
+
+    This is updates the defaults before expanding them, allowing
+    them to show up correctly in the help listing.
+    """
+
+    def expand_default(self, option):
+        if self.parser is not None:
+            self.parser._update_defaults(self.parser.defaults)
+        return optparse.IndentedHelpFormatter.expand_default(self, option)
+
+
+class CustomOptionParser(optparse.OptionParser):
+
+    def insert_option_group(self, idx, *args, **kwargs):
+        """Insert an OptionGroup at a given position."""
+        group = self.add_option_group(*args, **kwargs)
+
+        self.option_groups.pop()
+        self.option_groups.insert(idx, group)
+
+        return group
+
+    @property
+    def option_list_all(self):
+        """Get a list of all options, including those in option groups."""
+        res = self.option_list[:]
+        for i in self.option_groups:
+            res.extend(i.option_list)
+
+        return res
+
+
+class ConfigOptionParser(CustomOptionParser):
+    """Custom option parser which updates its defaults by checking the
+    configuration files and environmental variables"""
+
+    def __init__(self, *args, **kwargs):
+        self.name = kwargs.pop('name')
+
+        isolated = kwargs.pop("isolated", False)
+        self.config = Configuration(isolated)
+
+        assert self.name
+        optparse.OptionParser.__init__(self, *args, **kwargs)
+
+    def check_default(self, option, key, val):
+        try:
+            return option.check_value(key, val)
+        except optparse.OptionValueError as exc:
+            print("An error occurred during configuration: %s" % exc)
+            sys.exit(3)
+
+    def _get_ordered_configuration_items(self):
+        # Configuration gives keys in an unordered manner. Order them.
+        override_order = ["global", self.name, ":env:"]
+
+        # Pool the options into different groups
+        section_items = {name: [] for name in override_order}
+        for section_key, val in self.config.items():
+            # ignore empty values
+            if not val:
+                logger.debug(
+                    "Ignoring configuration key '%s' as it's value is empty.",
+                    section_key
+                )
+                continue
+
+            section, key = section_key.split(".", 1)
+            if section in override_order:
+                section_items[section].append((key, val))
+
+        # Yield each group in their override order
+        for section in override_order:
+            for key, val in section_items[section]:
+                yield key, val
+
+    def _update_defaults(self, defaults):
+        """Updates the given defaults with values from the config files and
+        the environ. Does a little special handling for certain types of
+        options (lists)."""
+
+        # Accumulate complex default state.
+        self.values = optparse.Values(self.defaults)
+        late_eval = set()
+        # Then set the options with those values
+        for key, val in self._get_ordered_configuration_items():
+            # '--' because configuration supports only long names
+            option = self.get_option('--' + key)
+
+            # Ignore options not present in this parser. E.g. non-globals put
+            # in [global] by users that want them to apply to all applicable
+            # commands.
+            if option is None:
+                continue
+
+            if option.action in ('store_true', 'store_false', 'count'):
+                try:
+                    val = strtobool(val)
+                except ValueError:
+                    error_msg = invalid_config_error_message(
+                        option.action, key, val
+                    )
+                    self.error(error_msg)
+
+            elif option.action == 'append':
+                val = val.split()
+                val = [self.check_default(option, key, v) for v in val]
+            elif option.action == 'callback':
+                late_eval.add(option.dest)
+                opt_str = option.get_opt_string()
+                val = option.convert_value(opt_str, val)
+                # From take_action
+                args = option.callback_args or ()
+                kwargs = option.callback_kwargs or {}
+                option.callback(option, opt_str, val, self, *args, **kwargs)
+            else:
+                val = self.check_default(option, key, val)
+
+            defaults[option.dest] = val
+
+        for key in late_eval:
+            defaults[key] = getattr(self.values, key)
+        self.values = None
+        return defaults
+
+    def get_default_values(self):
+        """Overriding to make updating the defaults after instantiation of
+        the option parser possible, _update_defaults() does the dirty work."""
+        if not self.process_default_values:
+            # Old, pre-Optik 1.5 behaviour.
+            return optparse.Values(self.defaults)
+
+        # Load the configuration, or error out in case of an error
+        try:
+            self.config.load()
+        except ConfigurationError as err:
+            self.exit(UNKNOWN_ERROR, str(err))
+
+        defaults = self._update_defaults(self.defaults.copy())  # ours
+        for option in self._get_all_options():
+            default = defaults.get(option.dest)
+            if isinstance(default, string_types):
+                opt_str = option.get_opt_string()
+                defaults[option.dest] = option.check_value(opt_str, default)
+        return optparse.Values(defaults)
+
+    def error(self, msg):
+        self.print_usage(sys.stderr)
+        self.exit(UNKNOWN_ERROR, "%s\n" % msg)
+
+
+def invalid_config_error_message(action, key, val):
+    """Returns a better error message when invalid configuration option
+    is provided."""
+    if action in ('store_true', 'store_false'):
+        return ("{0} is not a valid value for {1} option, "
+                "please specify a boolean value like yes/no, "
+                "true/false or 1/0 instead.").format(val, key)
+
+    return ("{0} is not a valid value for {1} option, "
+            "please specify a numerical value like 1/0 "
+            "instead.").format(val, key)

venv/lib/python3.8/site-packages/pip/_internal/cli/req_command.py

@@ -0,0 +1,333 @@
+"""Contains the Command base classes that depend on PipSession.
+
+The classes in this module are in a separate module so the commands not
+needing download / PackageFinder capability don't unnecessarily import the
+PackageFinder machinery and all its vendored dependencies, etc.
+"""
+
+import logging
+import os
+from functools import partial
+
+from pip._internal.cli.base_command import Command
+from pip._internal.cli.command_context import CommandContextMixIn
+from pip._internal.exceptions import CommandError
+from pip._internal.index.package_finder import PackageFinder
+from pip._internal.legacy_resolve import Resolver
+from pip._internal.models.selection_prefs import SelectionPreferences
+from pip._internal.network.download import Downloader
+from pip._internal.network.session import PipSession
+from pip._internal.operations.prepare import RequirementPreparer
+from pip._internal.req.constructors import (
+    install_req_from_editable,
+    install_req_from_line,
+    install_req_from_req_string,
+)
+from pip._internal.req.req_file import parse_requirements
+from pip._internal.self_outdated_check import (
+    make_link_collector,
+    pip_self_version_check,
+)
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from optparse import Values
+    from typing import List, Optional, Tuple
+    from pip._internal.cache import WheelCache
+    from pip._internal.models.target_python import TargetPython
+    from pip._internal.req.req_set import RequirementSet
+    from pip._internal.req.req_tracker import RequirementTracker
+    from pip._internal.utils.temp_dir import TempDirectory
+
+logger = logging.getLogger(__name__)
+
+
+class SessionCommandMixin(CommandContextMixIn):
+
+    """
+    A class mixin for command classes needing _build_session().
+    """
+    def __init__(self):
+        # type: () -> None
+        super(SessionCommandMixin, self).__init__()
+        self._session = None  # Optional[PipSession]
+
+    @classmethod
+    def _get_index_urls(cls, options):
+        # type: (Values) -> Optional[List[str]]
+        """Return a list of index urls from user-provided options."""
+        index_urls = []
+        if not getattr(options, "no_index", False):
+            url = getattr(options, "index_url", None)
+            if url:
+                index_urls.append(url)
+        urls = getattr(options, "extra_index_urls", None)
+        if urls:
+            index_urls.extend(urls)
+        # Return None rather than an empty list
+        return index_urls or None
+
+    def get_default_session(self, options):
+        # type: (Values) -> PipSession
+        """Get a default-managed session."""
+        if self._session is None:
+            self._session = self.enter_context(self._build_session(options))
+            # there's no type annotation on requests.Session, so it's
+            # automatically ContextManager[Any] and self._session becomes Any,
+            # then https://github.com/python/mypy/issues/7696 kicks in
+            assert self._session is not None
+        return self._session
+
+    def _build_session(self, options, retries=None, timeout=None):
+        # type: (Values, Optional[int], Optional[int]) -> PipSession
+        assert not options.cache_dir or os.path.isabs(options.cache_dir)
+        session = PipSession(
+            cache=(
+                os.path.join(options.cache_dir, "http")
+                if options.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),
+        )
+
+        # Handle custom ca-bundles from the user
+        if options.cert:
+            session.verify = options.cert
+
+        # Handle SSL client certificate
+        if options.client_cert:
+            session.cert = options.client_cert
+
+        # Handle timeouts
+        if options.timeout or timeout:
+            session.timeout = (
+                timeout if timeout is not None else options.timeout
+            )
+
+        # Handle configured proxies
+        if options.proxy:
+            session.proxies = {
+                "http": options.proxy,
+                "https": options.proxy,
+            }
+
+        # Determine if we can prompt the user for authentication or not
+        session.auth.prompting = not options.no_input
+
+        return session
+
+
+class IndexGroupCommand(Command, SessionCommandMixin):
+
+    """
+    Abstract base class for commands with the index_group options.
+
+    This also corresponds to the commands that permit the pip version check.
+    """
+
+    def handle_pip_version_check(self, options):
+        # type: (Values) -> None
+        """
+        Do the pip version check if not disabled.
+
+        This overrides the default behavior of not doing the check.
+        """
+        # Make sure the index_group options are present.
+        assert hasattr(options, 'no_index')
+
+        if options.disable_pip_version_check or options.no_index:
+            return
+
+        # Otherwise, check if we're using the latest version of pip available.
+        session = self._build_session(
+            options,
+            retries=0,
+            timeout=min(5, options.timeout)
+        )
+        with session:
+            pip_self_version_check(session, options)
+
+
+class RequirementCommand(IndexGroupCommand):
+
+    @staticmethod
+    def make_requirement_preparer(
+        temp_build_dir,           # type: TempDirectory
+        options,                  # type: Values
+        req_tracker,              # type: RequirementTracker
+        session,                  # type: PipSession
+        finder,                   # type: PackageFinder
+        use_user_site,            # type: bool
+        download_dir=None,        # type: str
+        wheel_download_dir=None,  # type: str
+    ):
+        # type: (...) -> RequirementPreparer
+        """
+        Create a RequirementPreparer instance for the given parameters.
+        """
+        downloader = Downloader(session, progress_bar=options.progress_bar)
+
+        temp_build_dir_path = temp_build_dir.path
+        assert temp_build_dir_path is not None
+
+        return RequirementPreparer(
+            build_dir=temp_build_dir_path,
+            src_dir=options.src_dir,
+            download_dir=download_dir,
+            wheel_download_dir=wheel_download_dir,
+            build_isolation=options.build_isolation,
+            req_tracker=req_tracker,
+            downloader=downloader,
+            finder=finder,
+            require_hashes=options.require_hashes,
+            use_user_site=use_user_site,
+        )
+
+    @staticmethod
+    def make_resolver(
+        preparer,                            # type: RequirementPreparer
+        finder,                              # type: PackageFinder
+        options,                             # type: Values
+        wheel_cache=None,                    # type: Optional[WheelCache]
+        use_user_site=False,                 # type: bool
+        ignore_installed=True,               # type: bool
+        ignore_requires_python=False,        # type: bool
+        force_reinstall=False,               # type: bool
+        upgrade_strategy="to-satisfy-only",  # type: str
+        use_pep517=None,                     # type: Optional[bool]
+        py_version_info=None            # type: Optional[Tuple[int, ...]]
+    ):
+        # type: (...) -> Resolver
+        """
+        Create a Resolver instance for the given parameters.
+        """
+        make_install_req = partial(
+            install_req_from_req_string,
+            isolated=options.isolated_mode,
+            wheel_cache=wheel_cache,
+            use_pep517=use_pep517,
+        )
+        return Resolver(
+            preparer=preparer,
+            finder=finder,
+            make_install_req=make_install_req,
+            use_user_site=use_user_site,
+            ignore_dependencies=options.ignore_dependencies,
+            ignore_installed=ignore_installed,
+            ignore_requires_python=ignore_requires_python,
+            force_reinstall=force_reinstall,
+            upgrade_strategy=upgrade_strategy,
+            py_version_info=py_version_info,
+        )
+
+    def populate_requirement_set(
+        self,
+        requirement_set,  # type: RequirementSet
+        args,             # type: List[str]
+        options,          # type: Values
+        finder,           # type: PackageFinder
+        session,          # type: PipSession
+        wheel_cache,      # type: Optional[WheelCache]
+    ):
+        # type: (...) -> None
+        """
+        Marshal cmd line args into a requirement set.
+        """
+        for filename in options.constraints:
+            for req_to_add in parse_requirements(
+                    filename,
+                    constraint=True, finder=finder, options=options,
+                    session=session, wheel_cache=wheel_cache):
+                req_to_add.is_direct = True
+                requirement_set.add_requirement(req_to_add)
+
+        for req in args:
+            req_to_add = install_req_from_line(
+                req, None, isolated=options.isolated_mode,
+                use_pep517=options.use_pep517,
+                wheel_cache=wheel_cache
+            )
+            req_to_add.is_direct = True
+            requirement_set.add_requirement(req_to_add)
+
+        for req in options.editables:
+            req_to_add = install_req_from_editable(
+                req,
+                isolated=options.isolated_mode,
+                use_pep517=options.use_pep517,
+                wheel_cache=wheel_cache
+            )
+            req_to_add.is_direct = True
+            requirement_set.add_requirement(req_to_add)
+
+        # NOTE: options.require_hashes may be set if --require-hashes is True
+        for filename in options.requirements:
+            for req_to_add in parse_requirements(
+                    filename,
+                    finder=finder, options=options, session=session,
+                    wheel_cache=wheel_cache,
+                    use_pep517=options.use_pep517):
+                req_to_add.is_direct = True
+                requirement_set.add_requirement(req_to_add)
+
+        # If any requirement has hash options, enable hash checking.
+        requirements = (
+            requirement_set.unnamed_requirements +
+            list(requirement_set.requirements.values())
+        )
+        if any(req.has_hash_options for req in requirements):
+            options.require_hashes = True
+
+        if not (args or options.editables or options.requirements):
+            opts = {'name': self.name}
+            if options.find_links:
+                raise CommandError(
+                    'You must give at least one requirement to %(name)s '
+                    '(maybe you meant "pip %(name)s %(links)s"?)' %
+                    dict(opts, links=' '.join(options.find_links)))
+            else:
+                raise CommandError(
+                    'You must give at least one requirement to %(name)s '
+                    '(see "pip help %(name)s")' % opts)
+
+    @staticmethod
+    def trace_basic_info(finder):
+        # type: (PackageFinder) -> None
+        """
+        Trace basic information about the provided objects.
+        """
+        # Display where finder is looking for packages
+        search_scope = finder.search_scope
+        locations = search_scope.get_formatted_locations()
+        if locations:
+            logger.info(locations)
+
+    def _build_package_finder(
+        self,
+        options,               # type: Values
+        session,               # type: PipSession
+        target_python=None,    # type: Optional[TargetPython]
+        ignore_requires_python=None,  # type: Optional[bool]
+    ):
+        # type: (...) -> PackageFinder
+        """
+        Create a package finder appropriate to this requirement command.
+
+        :param ignore_requires_python: Whether to ignore incompatible
+            "Requires-Python" values in links. Defaults to False.
+        """
+        link_collector = make_link_collector(session, options=options)
+        selection_prefs = SelectionPreferences(
+            allow_yanked=True,
+            format_control=options.format_control,
+            allow_all_prereleases=options.pre,
+            prefer_binary=options.prefer_binary,
+            ignore_requires_python=ignore_requires_python,
+        )
+
+        return PackageFinder.create(
+            link_collector=link_collector,
+            selection_prefs=selection_prefs,
+            target_python=target_python,
+        )

venv/lib/python3.8/site-packages/pip/_internal/cli/status_codes.py

@@ -0,0 +1,8 @@
+from __future__ import absolute_import
+
+SUCCESS = 0
+ERROR = 1
+UNKNOWN_ERROR = 2
+VIRTUALENV_NOT_FOUND = 3
+PREVIOUS_BUILD_DIR_ERROR = 4
+NO_MATCHES_FOUND = 23

venv/lib/python3.8/site-packages/pip/_internal/commands/__init__.py

@@ -0,0 +1,114 @@
+"""
+Package containing all pip commands
+"""
+
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import importlib
+from collections import OrderedDict, namedtuple
+
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Any
+    from pip._internal.cli.base_command import Command
+
+
+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 = 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.',
+    )),
+    ('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.',
+    )),
+])  # type: OrderedDict[str, CommandInfo]
+
+
+def create_command(name, **kwargs):
+    # type: (str, **Any) -> Command
+    """
+    Create an instance of the Command class with the given name.
+    """
+    module_path, class_name, summary = commands_dict[name]
+    module = importlib.import_module(module_path)
+    command_class = getattr(module, class_name)
+    command = command_class(name=name, summary=summary, **kwargs)
+
+    return command
+
+
+def get_similar_commands(name):
+    """Command name auto-correct."""
+    from difflib import get_close_matches
+
+    name = name.lower()
+
+    close_commands = get_close_matches(name, commands_dict.keys())
+
+    if close_commands:
+        return close_commands[0]
+    else:
+        return False

venv/lib/python3.8/site-packages/pip/_internal/commands/check.py

@@ -0,0 +1,45 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+import logging
+
+from pip._internal.cli.base_command import Command
+from pip._internal.operations.check import (
+    check_package_set,
+    create_package_set_from_installed,
+)
+from pip._internal.utils.misc import write_output
+
+logger = logging.getLogger(__name__)
+
+
+class CheckCommand(Command):
+    """Verify installed packages have compatible dependencies."""
+
+    usage = """
+      %prog [options]"""
+
+    def run(self, options, args):
+        package_set, parsing_probs = create_package_set_from_installed()
+        missing, conflicting = check_package_set(package_set)
+
+        for project_name in missing:
+            version = package_set[project_name].version
+            for dependency in missing[project_name]:
+                write_output(
+                    "%s %s requires %s, which is not installed.",
+                    project_name, version, dependency[0],
+                )
+
+        for project_name in conflicting:
+            version = package_set[project_name].version
+            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,
+                )
+
+        if missing or conflicting or parsing_probs:
+            return 1
+        else:
+            write_output("No broken requirements found.")

venv/lib/python3.8/site-packages/pip/_internal/commands/completion.py

@@ -0,0 +1,96 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import sys
+import textwrap
+
+from pip._internal.cli.base_command import Command
+from pip._internal.utils.misc import get_prog
+
+BASE_COMPLETION = """
+# pip %(shell)s completion start%(script)s# pip %(shell)s completion end
+"""
+
+COMPLETION_SCRIPTS = {
+    'bash': """
+        _pip_completion()
+        {
+            COMPREPLY=( $( COMP_WORDS="${COMP_WORDS[*]}" \\
+                           COMP_CWORD=$COMP_CWORD \\
+                           PIP_AUTO_COMPLETE=1 $1 2>/dev/null ) )
+        }
+        complete -o default -F _pip_completion %(prog)s
+    """,
+    'zsh': """
+        function _pip_completion {
+          local words cword
+          read -Ac words
+          read -cn cword
+          reply=( $( COMP_WORDS="$words[*]" \\
+                     COMP_CWORD=$(( cword-1 )) \\
+                     PIP_AUTO_COMPLETE=1 $words[1] 2>/dev/null ))
+        }
+        compctl -K _pip_completion %(prog)s
+    """,
+    'fish': """
+        function __fish_complete_pip
+            set -lx COMP_WORDS (commandline -o) ""
+            set -lx COMP_CWORD ( \\
+                math (contains -i -- (commandline -t) $COMP_WORDS)-1 \\
+            )
+            set -lx PIP_AUTO_COMPLETE 1
+            string split \\  -- (eval $COMP_WORDS[1])
+        end
+        complete -fa "(__fish_complete_pip)" -c %(prog)s
+    """,
+}
+
+
+class CompletionCommand(Command):
+    """A helper command to be used for command completion."""
+
+    ignore_require_venv = True
+
+    def __init__(self, *args, **kw):
+        super(CompletionCommand, self).__init__(*args, **kw)
+
+        cmd_opts = self.cmd_opts
+
+        cmd_opts.add_option(
+            '--bash', '-b',
+            action='store_const',
+            const='bash',
+            dest='shell',
+            help='Emit completion code for bash')
+        cmd_opts.add_option(
+            '--zsh', '-z',
+            action='store_const',
+            const='zsh',
+            dest='shell',
+            help='Emit completion code for zsh')
+        cmd_opts.add_option(
+            '--fish', '-f',
+            action='store_const',
+            const='fish',
+            dest='shell',
+            help='Emit completion code for fish')
+
+        self.parser.insert_option_group(0, cmd_opts)
+
+    def run(self, options, args):
+        """Prints the completion code of the given shell"""
+        shells = COMPLETION_SCRIPTS.keys()
+        shell_options = ['--' + shell for shell in sorted(shells)]
+        if options.shell in shells:
+            script = textwrap.dedent(
+                COMPLETION_SCRIPTS.get(options.shell, '') % {
+                    'prog': get_prog(),
+                }
+            )
+            print(BASE_COMPLETION % {'script': script, 'shell': options.shell})
+        else:
+            sys.stderr.write(
+                'ERROR: You must pass %s\n' % ' or '.join(shell_options)
+            )

venv/lib/python3.8/site-packages/pip/_internal/commands/configuration.py

@@ -0,0 +1,233 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+import logging
+import os
+import subprocess
+
+from pip._internal.cli.base_command import Command
+from pip._internal.cli.status_codes import ERROR, SUCCESS
+from pip._internal.configuration import (
+    Configuration,
+    get_configuration_files,
+    kinds,
+)
+from pip._internal.exceptions import PipError
+from pip._internal.utils.misc import get_prog, write_output
+
+logger = logging.getLogger(__name__)
+
+
+class ConfigurationCommand(Command):
+    """Manage local and global configuration.
+
+        Subcommands:
+
+        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
+
+        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
+        default.
+    """
+
+    ignore_require_venv = True
+    usage = """
+        %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
+    """
+
+    def __init__(self, *args, **kwargs):
+        super(ConfigurationCommand, self).__init__(*args, **kwargs)
+
+        self.configuration = None
+
+        self.cmd_opts.add_option(
+            '--editor',
+            dest='editor',
+            action='store',
+            default=None,
+            help=(
+                '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',
+            default=False,
+            help='Use the system-wide configuration file only'
+        )
+
+        self.cmd_opts.add_option(
+            '--user',
+            dest='user_file',
+            action='store_true',
+            default=False,
+            help='Use the user configuration file only'
+        )
+
+        self.cmd_opts.add_option(
+            '--site',
+            dest='site_file',
+            action='store_true',
+            default=False,
+            help='Use the current environment configuration file only'
+        )
+
+        self.parser.insert_option_group(0, self.cmd_opts)
+
+    def run(self, options, args):
+        handlers = {
+            "list": self.list_values,
+            "edit": self.open_in_editor,
+            "get": self.get_name,
+            "set": self.set_name_value,
+            "unset": self.unset_name
+        }
+
+        # Determine action
+        if not args or args[0] not in handlers:
+            logger.error("Need an action ({}) to perform.".format(
+                ", ".join(sorted(handlers)))
+            )
+            return ERROR
+
+        action = args[0]
+
+        # Determine which configuration files are to be loaded
+        #    Depends on whether the command is modifying.
+        try:
+            load_only = self._determine_file(
+                options, need_value=(action in ["get", "set", "unset", "edit"])
+            )
+        except PipError as e:
+            logger.error(e.args[0])
+            return ERROR
+
+        # Load a new configuration
+        self.configuration = Configuration(
+            isolated=options.isolated_mode, load_only=load_only
+        )
+        self.configuration.load()
+
+        # Error handling happens here, not in the action-handlers.
+        try:
+            handlers[action](options, args[1:])
+        except PipError as e:
+            logger.error(e.args[0])
+            return ERROR
+
+        return SUCCESS
+
+    def _determine_file(self, options, need_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:
+                return None
+            # Default to user, unless there's a site file.
+            elif any(
+                os.path.exists(site_config_file)
+                for site_config_file in get_configuration_files()[kinds.SITE]
+            ):
+                return kinds.SITE
+            else:
+                return kinds.USER
+        elif len(file_options) == 1:
+            return file_options[0]
+
+        raise PipError(
+            "Need exactly one file to operate upon "
+            "(--user, --site, --global) to perform."
+        )
+
+    def list_values(self, options, args):
+        self._get_n_args(args, "list", n=0)
+
+        for key, value in sorted(self.configuration.items()):
+            write_output("%s=%r", key, value)
+
+    def get_name(self, options, args):
+        key = self._get_n_args(args, "get [name]", n=1)
+        value = self.configuration.get_value(key)
+
+        write_output("%s", value)
+
+    def set_name_value(self, options, args):
+        key, value = self._get_n_args(args, "set [name] [value]", n=2)
+        self.configuration.set_value(key, value)
+
+        self._save_configuration()
+
+    def unset_name(self, options, args):
+        key = self._get_n_args(args, "unset [name]", n=1)
+        self.configuration.unset_value(key)
+
+        self._save_configuration()
+
+    def open_in_editor(self, options, args):
+        editor = self._determine_editor(options)
+
+        fname = self.configuration.get_file_to_edit()
+        if fname is None:
+            raise PipError("Could not determine appropriate file.")
+
+        try:
+            subprocess.check_call([editor, fname])
+        except subprocess.CalledProcessError as e:
+            raise PipError(
+                "Editor Subprocess exited with exit code {}"
+                .format(e.returncode)
+            )
+
+    def _get_n_args(self, args, example, n):
+        """Helper to make sure the command got the right number of arguments
+        """
+        if len(args) != n:
+            msg = (
+                'Got unexpected number of arguments, expected {}. '
+                '(example: "{} config {}")'
+            ).format(n, get_prog(), example)
+            raise PipError(msg)
+
+        if n == 1:
+            return args[0]
+        else:
+            return args
+
+    def _save_configuration(self):
+        # We successfully ran a modifying command. Need to save the
+        # configuration.
+        try:
+            self.configuration.save()
+        except Exception:
+            logger.error(
+                "Unable to save configuration. Please report this as a bug.",
+                exc_info=1
+            )
+            raise PipError("Internal Error.")
+
+    def _determine_editor(self, options):
+        if options.editor is not None:
+            return options.editor
+        elif "VISUAL" in os.environ:
+            return os.environ["VISUAL"]
+        elif "EDITOR" in os.environ:
+            return os.environ["EDITOR"]
+        else:
+            raise PipError("Could not determine editor to use.")

venv/lib/python3.8/site-packages/pip/_internal/commands/debug.py

@@ -0,0 +1,142 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import locale
+import logging
+import os
+import sys
+
+from pip._vendor.certifi import where
+
+from pip._internal.cli import cmdoptions
+from pip._internal.cli.base_command import Command
+from pip._internal.cli.cmdoptions import make_target_python
+from pip._internal.cli.status_codes import SUCCESS
+from pip._internal.utils.logging import indent_log
+from pip._internal.utils.misc import get_pip_version
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Any, List, Optional
+    from optparse import Values
+
+logger = logging.getLogger(__name__)
+
+
+def show_value(name, value):
+    # type: (str, Optional[str]) -> None
+    logger.info('{}: {}'.format(name, value))
+
+
+def show_sys_implementation():
+    # type: () -> None
+    logger.info('sys.implementation:')
+    if hasattr(sys, 'implementation'):
+        implementation = sys.implementation  # type: ignore
+        implementation_name = implementation.name
+    else:
+        implementation_name = ''
+
+    with indent_log():
+        show_value('name', implementation_name)
+
+
+def show_tags(options):
+    # type: (Values) -> None
+    tag_limit = 10
+
+    target_python = make_target_python(options)
+    tags = target_python.get_tags()
+
+    # Display the target options that were explicitly provided.
+    formatted_target = target_python.format_given()
+    suffix = ''
+    if formatted_target:
+        suffix = ' (target: {})'.format(formatted_target)
+
+    msg = 'Compatible tags: {}{}'.format(len(tags), suffix)
+    logger.info(msg)
+
+    if options.verbose < 1 and len(tags) > tag_limit:
+        tags_limited = True
+        tags = tags[:tag_limit]
+    else:
+        tags_limited = False
+
+    with indent_log():
+        for tag in tags:
+            logger.info(str(tag))
+
+        if tags_limited:
+            msg = (
+                '...\n'
+                '[First {tag_limit} tags shown. Pass --verbose to show all.]'
+            ).format(tag_limit=tag_limit)
+            logger.info(msg)
+
+
+def ca_bundle_info(config):
+    levels = set()
+    for key, value in config.items():
+        levels.add(key.split('.')[0])
+
+    if not levels:
+        return "Not specified"
+
+    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'
+
+    levels.remove('global')
+    return ", ".join(levels)
+
+
+class DebugCommand(Command):
+    """
+    Display debug information.
+    """
+
+    usage = """
+      %prog <options>"""
+    ignore_require_venv = True
+
+    def __init__(self, *args, **kw):
+        super(DebugCommand, self).__init__(*args, **kw)
+
+        cmd_opts = self.cmd_opts
+        cmdoptions.add_target_python_options(cmd_opts)
+        self.parser.insert_option_group(0, cmd_opts)
+        self.parser.config.load()
+
+    def run(self, options, args):
+        # type: (Values, List[Any]) -> int
+        logger.warning(
+            "This command is only meant for debugging. "
+            "Do not use this with automation for parsing and getting these "
+            "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(
+            'locale.getpreferredencoding', locale.getpreferredencoding(),
+        )
+        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("pip._vendor.certifi.where()", where())
+
+        show_tags(options)
+
+        return SUCCESS

venv/lib/python3.8/site-packages/pip/_internal/commands/download.py

@@ -0,0 +1,147 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import logging
+import os
+
+from pip._internal.cli import cmdoptions
+from pip._internal.cli.cmdoptions import make_target_python
+from pip._internal.cli.req_command import RequirementCommand
+from pip._internal.req import RequirementSet
+from pip._internal.req.req_tracker import get_requirement_tracker
+from pip._internal.utils.misc import ensure_dir, normalize_path, write_output
+from pip._internal.utils.temp_dir import TempDirectory
+
+logger = logging.getLogger(__name__)
+
+
+class DownloadCommand(RequirementCommand):
+    """
+    Download packages from:
+
+    - PyPI (and other indexes) using requirement specifiers.
+    - VCS project urls.
+    - Local project directories.
+    - Local or remote source archives.
+
+    pip also supports downloading from "requirements files", which provide
+    an easy way to specify a whole environment to be downloaded.
+    """
+
+    usage = """
+      %prog [options] <requirement specifier> [package-index-options] ...
+      %prog [options] -r <requirements file> [package-index-options] ...
+      %prog [options] <vcs project url> ...
+      %prog [options] <local project path> ...
+      %prog [options] <archive url/path> ..."""
+
+    def __init__(self, *args, **kw):
+        super(DownloadCommand, self).__init__(*args, **kw)
+
+        cmd_opts = self.cmd_opts
+
+        cmd_opts.add_option(cmdoptions.constraints())
+        cmd_opts.add_option(cmdoptions.requirements())
+        cmd_opts.add_option(cmdoptions.build_dir())
+        cmd_opts.add_option(cmdoptions.no_deps())
+        cmd_opts.add_option(cmdoptions.global_options())
+        cmd_opts.add_option(cmdoptions.no_binary())
+        cmd_opts.add_option(cmdoptions.only_binary())
+        cmd_opts.add_option(cmdoptions.prefer_binary())
+        cmd_opts.add_option(cmdoptions.src())
+        cmd_opts.add_option(cmdoptions.pre())
+        cmd_opts.add_option(cmdoptions.no_clean())
+        cmd_opts.add_option(cmdoptions.require_hashes())
+        cmd_opts.add_option(cmdoptions.progress_bar())
+        cmd_opts.add_option(cmdoptions.no_build_isolation())
+        cmd_opts.add_option(cmdoptions.use_pep517())
+        cmd_opts.add_option(cmdoptions.no_use_pep517())
+
+        cmd_opts.add_option(
+            '-d', '--dest', '--destination-dir', '--destination-directory',
+            dest='download_dir',
+            metavar='dir',
+            default=os.curdir,
+            help=("Download packages into <dir>."),
+        )
+
+        cmdoptions.add_target_python_options(cmd_opts)
+
+        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, cmd_opts)
+
+    def run(self, options, args):
+        options.ignore_installed = True
+        # editable doesn't really make sense for `pip download`, but the bowels
+        # of the RequirementSet code require that property.
+        options.editables = []
+
+        cmdoptions.check_dist_restriction(options)
+
+        options.download_dir = normalize_path(options.download_dir)
+
+        ensure_dir(options.download_dir)
+
+        session = self.get_default_session(options)
+
+        target_python = make_target_python(options)
+        finder = self._build_package_finder(
+            options=options,
+            session=session,
+            target_python=target_python,
+        )
+        build_delete = (not (options.no_clean or options.build_dir))
+
+        with get_requirement_tracker() as req_tracker, TempDirectory(
+            options.build_dir, delete=build_delete, kind="download"
+        ) as directory:
+
+            requirement_set = RequirementSet()
+            self.populate_requirement_set(
+                requirement_set,
+                args,
+                options,
+                finder,
+                session,
+                None
+            )
+
+            preparer = self.make_requirement_preparer(
+                temp_build_dir=directory,
+                options=options,
+                req_tracker=req_tracker,
+                session=session,
+                finder=finder,
+                download_dir=options.download_dir,
+                use_user_site=False,
+            )
+
+            resolver = self.make_resolver(
+                preparer=preparer,
+                finder=finder,
+                options=options,
+                py_version_info=options.python_version,
+            )
+
+            self.trace_basic_info(finder)
+
+            resolver.resolve(requirement_set)
+
+            downloaded = ' '.join([
+                req.name for req in requirement_set.successfully_downloaded
+            ])
+            if downloaded:
+                write_output('Successfully downloaded %s', downloaded)
+
+            # Clean up
+            if not options.no_clean:
+                requirement_set.cleanup_files()
+
+        return requirement_set

venv/lib/python3.8/site-packages/pip/_internal/commands/freeze.py

@@ -0,0 +1,103 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import sys
+
+from pip._internal.cache import WheelCache
+from pip._internal.cli import cmdoptions
+from pip._internal.cli.base_command import Command
+from pip._internal.models.format_control import FormatControl
+from pip._internal.operations.freeze import freeze
+from pip._internal.utils.compat import stdlib_pkgs
+
+DEV_PKGS = {'pip', 'setuptools', 'distribute', 'wheel'}
+
+
+class FreezeCommand(Command):
+    """
+    Output installed packages in requirements format.
+
+    packages are listed in a case-insensitive sorted order.
+    """
+
+    usage = """
+      %prog [options]"""
+    log_streams = ("ext://sys.stderr", "ext://sys.stderr")
+
+    def __init__(self, *args, **kw):
+        super(FreezeCommand, self).__init__(*args, **kw)
+
+        self.cmd_opts.add_option(
+            '-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.")
+        self.cmd_opts.add_option(
+            '-f', '--find-links',
+            dest='find_links',
+            action='append',
+            default=[],
+            metavar='URL',
+            help='URL for finding packages, which will be added to the '
+                 'output.')
+        self.cmd_opts.add_option(
+            '-l', '--local',
+            dest='local',
+            action='store_true',
+            default=False,
+            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',
+            default=False,
+            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:'
+                 ' %s' % ', '.join(DEV_PKGS))
+        self.cmd_opts.add_option(
+            '--exclude-editable',
+            dest='exclude_editable',
+            action='store_true',
+            help='Exclude editable package from output.')
+
+        self.parser.insert_option_group(0, self.cmd_opts)
+
+    def run(self, options, args):
+        format_control = FormatControl(set(), set())
+        wheel_cache = WheelCache(options.cache_dir, format_control)
+        skip = set(stdlib_pkgs)
+        if not options.freeze_all:
+            skip.update(DEV_PKGS)
+
+        cmdoptions.check_list_path_option(options)
+
+        freeze_kwargs = dict(
+            requirement=options.requirements,
+            find_links=options.find_links,
+            local_only=options.local,
+            user_only=options.user,
+            paths=options.path,
+            skip_regex=options.skip_requirements_regex,
+            isolated=options.isolated_mode,
+            wheel_cache=wheel_cache,
+            skip=skip,
+            exclude_editable=options.exclude_editable,
+        )
+
+        try:
+            for line in freeze(**freeze_kwargs):
+                sys.stdout.write(line + '\n')
+        finally:
+            wheel_cache.cleanup()

venv/lib/python3.8/site-packages/pip/_internal/commands/hash.py

@@ -0,0 +1,58 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import hashlib
+import logging
+import sys
+
+from pip._internal.cli.base_command import Command
+from pip._internal.cli.status_codes import ERROR
+from pip._internal.utils.hashes import FAVORITE_HASH, STRONG_HASHES
+from pip._internal.utils.misc import read_chunks, write_output
+
+logger = logging.getLogger(__name__)
+
+
+class HashCommand(Command):
+    """
+    Compute a hash of a local package archive.
+
+    These can be used with --hash in a requirements file to do repeatable
+    installs.
+    """
+
+    usage = '%prog [options] <file> ...'
+    ignore_require_venv = True
+
+    def __init__(self, *args, **kw):
+        super(HashCommand, self).__init__(*args, **kw)
+        self.cmd_opts.add_option(
+            '-a', '--algorithm',
+            dest='algorithm',
+            choices=STRONG_HASHES,
+            action='store',
+            default=FAVORITE_HASH,
+            help='The hash algorithm to use: one of %s' %
+                 ', '.join(STRONG_HASHES))
+        self.parser.insert_option_group(0, self.cmd_opts)
+
+    def run(self, options, args):
+        if not args:
+            self.parser.print_usage(sys.stderr)
+            return ERROR
+
+        algorithm = options.algorithm
+        for path in args:
+            write_output('%s:\n--hash=%s:%s',
+                         path, algorithm, _hash_of_file(path, algorithm))
+
+
+def _hash_of_file(path, algorithm):
+    """Return the hash digest of a file."""
+    with open(path, 'rb') as archive:
+        hash = hashlib.new(algorithm)
+        for chunk in read_chunks(archive):
+            hash.update(chunk)
+    return hash.hexdigest()

venv/lib/python3.8/site-packages/pip/_internal/commands/help.py

@@ -0,0 +1,41 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+from pip._internal.cli.base_command import Command
+from pip._internal.cli.status_codes import SUCCESS
+from pip._internal.exceptions import CommandError
+
+
+class HelpCommand(Command):
+    """Show help for commands"""
+
+    usage = """
+      %prog <command>"""
+    ignore_require_venv = True
+
+    def run(self, options, args):
+        from pip._internal.commands import (
+            commands_dict, create_command, get_similar_commands,
+        )
+
+        try:
+            # 'pip help' with no args is handled by pip.__init__.parseopt()
+            cmd_name = args[0]  # the command we need help for
+        except IndexError:
+            return SUCCESS
+
+        if cmd_name not in commands_dict:
+            guess = get_similar_commands(cmd_name)
+
+            msg = ['unknown command "%s"' % cmd_name]
+            if guess:
+                msg.append('maybe you meant "%s"' % guess)
+
+            raise CommandError(' - '.join(msg))
+
+        command = create_command(cmd_name)
+        command.parser.print_help()
+
+        return SUCCESS

venv/lib/python3.8/site-packages/pip/_internal/commands/install.py

@@ -0,0 +1,701 @@
+# The following comment should be removed at some point in the future.
+# It's included for now because without it InstallCommand.run() has a
+# couple errors where we have to know req.name is str rather than
+# Optional[str] for the InstallRequirement req.
+# mypy: strict-optional=False
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import errno
+import logging
+import operator
+import os
+import shutil
+import site
+from optparse import SUPPRESS_HELP
+
+from pip._vendor import pkg_resources
+from pip._vendor.packaging.utils import canonicalize_name
+
+from pip._internal.cache import WheelCache
+from pip._internal.cli import cmdoptions
+from pip._internal.cli.cmdoptions import make_target_python
+from pip._internal.cli.req_command import RequirementCommand
+from pip._internal.cli.status_codes import ERROR, SUCCESS
+from pip._internal.exceptions import (
+    CommandError,
+    InstallationError,
+    PreviousBuildDirError,
+)
+from pip._internal.locations import distutils_scheme
+from pip._internal.operations.check import check_install_conflicts
+from pip._internal.req import RequirementSet, install_given_reqs
+from pip._internal.req.req_tracker import get_requirement_tracker
+from pip._internal.utils.deprecation import deprecated
+from pip._internal.utils.distutils_args import parse_distutils_args
+from pip._internal.utils.filesystem import test_writable_dir
+from pip._internal.utils.misc import (
+    ensure_dir,
+    get_installed_version,
+    protect_pip_from_modification_on_windows,
+    write_output,
+)
+from pip._internal.utils.temp_dir import TempDirectory
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.virtualenv import virtualenv_no_global
+from pip._internal.wheel_builder import build, should_build_for_install_command
+
+if MYPY_CHECK_RUNNING:
+    from optparse import Values
+    from typing import Any, Iterable, List, Optional
+
+    from pip._internal.models.format_control import FormatControl
+    from pip._internal.req.req_install import InstallRequirement
+    from pip._internal.wheel_builder import BinaryAllowedPredicate
+
+
+logger = logging.getLogger(__name__)
+
+
+def get_check_binary_allowed(format_control):
+    # type: (FormatControl) -> BinaryAllowedPredicate
+    def check_binary_allowed(req):
+        # type: (InstallRequirement) -> bool
+        if req.use_pep517:
+            return True
+        canonical_name = canonicalize_name(req.name)
+        allowed_formats = format_control.get_allowed_formats(canonical_name)
+        return "binary" in allowed_formats
+
+    return check_binary_allowed
+
+
+class InstallCommand(RequirementCommand):
+    """
+    Install packages from:
+
+    - PyPI (and other indexes) using requirement specifiers.
+    - VCS project urls.
+    - Local project directories.
+    - Local or remote source archives.
+
+    pip also supports installing from "requirements files", which provide
+    an easy way to specify a whole environment to be installed.
+    """
+
+    usage = """
+      %prog [options] <requirement specifier> [package-index-options] ...
+      %prog [options] -r <requirements file> [package-index-options] ...
+      %prog [options] [-e] <vcs project url> ...
+      %prog [options] [-e] <local project path> ...
+      %prog [options] <archive url/path> ..."""
+
+    def __init__(self, *args, **kw):
+        super(InstallCommand, self).__init__(*args, **kw)
+
+        cmd_opts = self.cmd_opts
+
+        cmd_opts.add_option(cmdoptions.requirements())
+        cmd_opts.add_option(cmdoptions.constraints())
+        cmd_opts.add_option(cmdoptions.no_deps())
+        cmd_opts.add_option(cmdoptions.pre())
+
+        cmd_opts.add_option(cmdoptions.editable())
+        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.'
+        )
+        cmdoptions.add_target_python_options(cmd_opts)
+
+        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.)")
+        cmd_opts.add_option(
+            '--no-user',
+            dest='use_user_site',
+            action='store_false',
+            help=SUPPRESS_HELP)
+        cmd_opts.add_option(
+            '--root',
+            dest='root_path',
+            metavar='dir',
+            default=None,
+            help="Install everything relative to this alternate root "
+                 "directory.")
+        cmd_opts.add_option(
+            '--prefix',
+            dest='prefix_path',
+            metavar='dir',
+            default=None,
+            help="Installation prefix where lib, bin and other top-level "
+                 "folders are placed")
+
+        cmd_opts.add_option(cmdoptions.build_dir())
+
+        cmd_opts.add_option(cmdoptions.src())
+
+        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.'
+        )
+
+        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).'
+        )
+
+        cmd_opts.add_option(
+            '--force-reinstall',
+            dest='force_reinstall',
+            action='store_true',
+            help='Reinstall all packages even if they are already '
+                 'up-to-date.')
+
+        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!'
+        )
+
+        cmd_opts.add_option(cmdoptions.ignore_requires_python())
+        cmd_opts.add_option(cmdoptions.no_build_isolation())
+        cmd_opts.add_option(cmdoptions.use_pep517())
+        cmd_opts.add_option(cmdoptions.no_use_pep517())
+
+        cmd_opts.add_option(cmdoptions.install_options())
+        cmd_opts.add_option(cmdoptions.global_options())
+
+        cmd_opts.add_option(
+            "--compile",
+            action="store_true",
+            dest="compile",
+            default=True,
+            help="Compile Python source files to bytecode",
+        )
+
+        cmd_opts.add_option(
+            "--no-compile",
+            action="store_false",
+            dest="compile",
+            help="Do not compile Python source files to bytecode",
+        )
+
+        cmd_opts.add_option(
+            "--no-warn-script-location",
+            action="store_false",
+            dest="warn_script_location",
+            default=True,
+            help="Do not warn when installing scripts outside PATH",
+        )
+        cmd_opts.add_option(
+            "--no-warn-conflicts",
+            action="store_false",
+            dest="warn_about_conflicts",
+            default=True,
+            help="Do not warn about broken dependencies",
+        )
+
+        cmd_opts.add_option(cmdoptions.no_binary())
+        cmd_opts.add_option(cmdoptions.only_binary())
+        cmd_opts.add_option(cmdoptions.prefer_binary())
+        cmd_opts.add_option(cmdoptions.no_clean())
+        cmd_opts.add_option(cmdoptions.require_hashes())
+        cmd_opts.add_option(cmdoptions.progress_bar())
+
+        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, cmd_opts)
+
+    def run(self, options, args):
+        # type: (Values, List[Any]) -> int
+        cmdoptions.check_install_build_global(options)
+        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 []
+
+        options.use_user_site = decide_user_install(
+            options.use_user_site,
+            prefix_path=options.prefix_path,
+            target_dir=options.target_dir,
+            root_path=options.root_path,
+            isolated_mode=options.isolated_mode,
+        )
+
+        target_temp_dir = None  # type: Optional[TempDirectory]
+        target_temp_dir_path = None  # type: Optional[str]
+        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)):
+                raise CommandError(
+                    "Target path exists but is not a directory, will not "
+                    "continue."
+                )
+
+            # Create a target directory for using with the target option
+            target_temp_dir = TempDirectory(kind="target")
+            target_temp_dir_path = target_temp_dir.path
+
+        global_options = options.global_options or []
+
+        session = self.get_default_session(options)
+
+        target_python = make_target_python(options)
+        finder = self._build_package_finder(
+            options=options,
+            session=session,
+            target_python=target_python,
+            ignore_requires_python=options.ignore_requires_python,
+        )
+        build_delete = (not (options.no_clean or options.build_dir))
+        wheel_cache = WheelCache(options.cache_dir, options.format_control)
+
+        with get_requirement_tracker() as req_tracker, TempDirectory(
+            options.build_dir, delete=build_delete, kind="install"
+        ) as directory:
+            requirement_set = RequirementSet(
+                check_supported_wheels=not options.target_dir,
+            )
+
+            try:
+                self.populate_requirement_set(
+                    requirement_set, args, options, finder, session,
+                    wheel_cache
+                )
+
+                warn_deprecated_install_options(
+                    requirement_set, options.install_options
+                )
+
+                preparer = self.make_requirement_preparer(
+                    temp_build_dir=directory,
+                    options=options,
+                    req_tracker=req_tracker,
+                    session=session,
+                    finder=finder,
+                    use_user_site=options.use_user_site,
+                )
+                resolver = self.make_resolver(
+                    preparer=preparer,
+                    finder=finder,
+                    options=options,
+                    wheel_cache=wheel_cache,
+                    use_user_site=options.use_user_site,
+                    ignore_installed=options.ignore_installed,
+                    ignore_requires_python=options.ignore_requires_python,
+                    force_reinstall=options.force_reinstall,
+                    upgrade_strategy=upgrade_strategy,
+                    use_pep517=options.use_pep517,
+                )
+
+                self.trace_basic_info(finder)
+
+                resolver.resolve(requirement_set)
+
+                try:
+                    pip_req = requirement_set.get_requirement("pip")
+                except KeyError:
+                    modifying_pip = None
+                else:
+                    # 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
+                )
+
+                reqs_to_build = [
+                    r for r in requirement_set.requirements.values()
+                    if should_build_for_install_command(
+                        r, check_binary_allowed
+                    )
+                ]
+
+                _, build_failures = build(
+                    reqs_to_build,
+                    wheel_cache=wheel_cache,
+                    build_options=[],
+                    global_options=[],
+                )
+
+                # If we're using PEP 517, we cannot do a direct install
+                # so we fail here.
+                # We don't care about failures building legacy
+                # requirements, as we'll fall through to a direct
+                # install for those.
+                pep517_build_failures = [
+                    r for r in build_failures if r.use_pep517
+                ]
+                if pep517_build_failures:
+                    raise InstallationError(
+                        "Could not build wheels for {} which use"
+                        " PEP 517 and cannot be installed directly".format(
+                            ", ".join(r.name for r in pep517_build_failures)))
+
+                to_install = resolver.get_installation_order(
+                    requirement_set
+                )
+
+                # Consistency Checking of the package set we're installing.
+                should_warn_about_conflicts = (
+                    not options.ignore_dependencies and
+                    options.warn_about_conflicts
+                )
+                if should_warn_about_conflicts:
+                    self._warn_about_conflicts(to_install)
+
+                # Don't warn about script install locations if
+                # --target has been specified
+                warn_script_location = options.warn_script_location
+                if options.target_dir:
+                    warn_script_location = False
+
+                installed = install_given_reqs(
+                    to_install,
+                    install_options,
+                    global_options,
+                    root=options.root_path,
+                    home=target_temp_dir_path,
+                    prefix=options.prefix_path,
+                    pycompile=options.compile,
+                    warn_script_location=warn_script_location,
+                    use_user_site=options.use_user_site,
+                )
+
+                lib_locations = get_lib_location_guesses(
+                    user=options.use_user_site,
+                    home=target_temp_dir_path,
+                    root=options.root_path,
+                    prefix=options.prefix_path,
+                    isolated=options.isolated_mode,
+                )
+                working_set = pkg_resources.WorkingSet(lib_locations)
+
+                installed.sort(key=operator.attrgetter('name'))
+                items = []
+                for result in installed:
+                    item = result.name
+                    try:
+                        installed_version = get_installed_version(
+                            result.name, working_set=working_set
+                        )
+                        if installed_version:
+                            item += '-' + installed_version
+                    except Exception:
+                        pass
+                    items.append(item)
+                installed_desc = ' '.join(items)
+                if installed_desc:
+                    write_output(
+                        'Successfully installed %s', installed_desc,
+                    )
+            except EnvironmentError as error:
+                show_traceback = (self.verbosity >= 1)
+
+                message = create_env_error_message(
+                    error, show_traceback, options.use_user_site,
+                )
+                logger.error(message, exc_info=show_traceback)
+
+                return ERROR
+            except PreviousBuildDirError:
+                options.no_clean = True
+                raise
+            finally:
+                # Clean up
+                if not options.no_clean:
+                    requirement_set.cleanup_files()
+                    wheel_cache.cleanup()
+
+        if options.target_dir:
+            self._handle_target_dir(
+                options.target_dir, target_temp_dir, options.upgrade
+            )
+
+        return SUCCESS
+
+    def _handle_target_dir(self, target_dir, target_temp_dir, upgrade):
+        ensure_dir(target_dir)
+
+        # Checking both purelib and platlib directories for installed
+        # packages to be moved to target directory
+        lib_dir_list = []
+
+        with target_temp_dir:
+            # Checking both purelib and platlib directories for installed
+            # packages to be moved to target directory
+            scheme = distutils_scheme('', home=target_temp_dir.path)
+            purelib_dir = scheme['purelib']
+            platlib_dir = scheme['platlib']
+            data_dir = scheme['data']
+
+            if os.path.exists(purelib_dir):
+                lib_dir_list.append(purelib_dir)
+            if os.path.exists(platlib_dir) and platlib_dir != purelib_dir:
+                lib_dir_list.append(platlib_dir)
+            if os.path.exists(data_dir):
+                lib_dir_list.append(data_dir)
+
+            for lib_dir in lib_dir_list:
+                for item in os.listdir(lib_dir):
+                    if lib_dir == data_dir:
+                        ddir = os.path.join(data_dir, item)
+                        if any(s.startswith(ddir) for s in lib_dir_list[:-1]):
+                            continue
+                    target_item_dir = os.path.join(target_dir, item)
+                    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
+                            )
+                            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
+                            )
+                            continue
+                        if os.path.isdir(target_item_dir):
+                            shutil.rmtree(target_item_dir)
+                        else:
+                            os.remove(target_item_dir)
+
+                    shutil.move(
+                        os.path.join(lib_dir, item),
+                        target_item_dir
+                    )
+
+    def _warn_about_conflicts(self, to_install):
+        try:
+            package_set, _dep_info = check_install_conflicts(to_install)
+        except Exception:
+            logger.error("Error checking for conflicts.", exc_info=True)
+            return
+        missing, conflicting = _dep_info
+
+        # NOTE: There is some duplication here from pip check
+        for project_name in missing:
+            version = package_set[project_name][0]
+            for dependency in missing[project_name]:
+                logger.critical(
+                    "%s %s requires %s, which is not installed.",
+                    project_name, version, dependency[1],
+                )
+
+        for project_name in conflicting:
+            version = package_set[project_name][0]
+            for dep_name, dep_version, req in conflicting[project_name]:
+                logger.critical(
+                    "%s %s has requirement %s, but you'll have %s %s which is "
+                    "incompatible.",
+                    project_name, version, req, dep_name, dep_version,
+                )
+
+
+def get_lib_location_guesses(*args, **kwargs):
+    scheme = distutils_scheme('', *args, **kwargs)
+    return [scheme['purelib'], scheme['platlib']]
+
+
+def site_packages_writable(**kwargs):
+    return all(
+        test_writable_dir(d) for d in set(get_lib_location_guesses(**kwargs))
+    )
+
+
+def decide_user_install(
+    use_user_site,  # type: Optional[bool]
+    prefix_path=None,  # type: Optional[str]
+    target_dir=None,  # type: Optional[str]
+    root_path=None,  # type: Optional[str]
+    isolated_mode=False,  # type: bool
+):
+    # type: (...) -> bool
+    """Determine whether to do a user install based on the input options.
+
+    If use_user_site is False, no additional checks are done.
+    If use_user_site is True, it is checked for compatibility with other
+    options.
+    If use_user_site is None, the default behaviour depends on the environment,
+    which is provided by the other arguments.
+    """
+    # In some cases (config from tox), use_user_site can be set to an integer
+    # rather than a bool, which 'use_user_site is False' wouldn't catch.
+    if (use_user_site is not None) and (not use_user_site):
+        logger.debug("Non-user install by explicit request")
+        return False
+
+    if use_user_site:
+        if prefix_path:
+            raise CommandError(
+                "Can not combine '--user' and '--prefix' as they imply "
+                "different installation locations"
+            )
+        if virtualenv_no_global():
+            raise InstallationError(
+                "Can not perform a '--user' install. User site-packages "
+                "are not visible in this virtualenv."
+            )
+        logger.debug("User install by explicit request")
+        return True
+
+    # If we are here, user installs have not been explicitly requested/avoided
+    assert use_user_site is None
+
+    # user install incompatible with --prefix/--target
+    if prefix_path or target_dir:
+        logger.debug("Non-user install due to --prefix or --target option")
+        return False
+
+    # If user installs are not enabled, choose a non-user install
+    if not site.ENABLE_USER_SITE:
+        logger.debug("Non-user install because user site-packages disabled")
+        return False
+
+    # If we have permission for a non-user install, do that,
+    # otherwise do a user install.
+    if site_packages_writable(root=root_path, isolated=isolated_mode):
+        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 warn_deprecated_install_options(requirement_set, options):
+    # type: (RequirementSet, 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):
+        # type: (Iterable[str]) -> List[str]
+        return ["--{}".format(name.replace("_", "-")) for name in option_names]
+
+    requirements = (
+        requirement_set.unnamed_requirements +
+        list(requirement_set.requirements.values())
+    )
+
+    offenders = []
+
+    for requirement in requirements:
+        install_options = requirement.options.get("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
+
+    deprecated(
+        reason=(
+            "Location-changing options found in --install-option: {}. "
+            "This configuration may cause unexpected behavior and is "
+            "unsupported.".format(
+                "; ".join(offenders)
+            )
+        ),
+        replacement=(
+            "using pip-level options like --user, --prefix, --root, and "
+            "--target"
+        ),
+        gone_in="20.2",
+        issue=7309,
+    )
+
+
+def create_env_error_message(error, show_traceback, using_user_site):
+    """Format an error message for an EnvironmentError
+
+    It may occur anytime during the execution of the install command.
+    """
+    parts = []
+
+    # Mention the error if we are not going to show a traceback
+    parts.append("Could not install packages due to an EnvironmentError")
+    if not show_traceback:
+        parts.append(": ")
+        parts.append(str(error))
+    else:
+        parts.append(".")
+
+    # Spilt the error indication from a helper message (if any)
+    parts[-1] += "\n"
+
+    # Suggest useful actions to the user:
+    #  (1) using user site-packages or (2) verifying the permissions
+    if error.errno == errno.EACCES:
+        user_option_part = "Consider using the `--user` option"
+        permissions_part = "Check the permissions"
+
+        if not using_user_site:
+            parts.extend([
+                user_option_part, " or ",
+                permissions_part.lower(),
+            ])
+        else:
+            parts.append(permissions_part)
+        parts.append(".\n")
+
+    return "".join(parts).strip() + "\n"

venv/lib/python3.8/site-packages/pip/_internal/commands/list.py

@@ -0,0 +1,313 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import json
+import logging
+
+from pip._vendor import six
+from pip._vendor.six.moves import zip_longest
+
+from pip._internal.cli import cmdoptions
+from pip._internal.cli.req_command import IndexGroupCommand
+from pip._internal.exceptions import CommandError
+from pip._internal.index.package_finder import PackageFinder
+from pip._internal.models.selection_prefs import SelectionPreferences
+from pip._internal.self_outdated_check import make_link_collector
+from pip._internal.utils.misc import (
+    dist_is_editable,
+    get_installed_distributions,
+    write_output,
+)
+from pip._internal.utils.packaging import get_installer
+
+logger = logging.getLogger(__name__)
+
+
+class ListCommand(IndexGroupCommand):
+    """
+    List installed packages, including editables.
+
+    Packages are listed in a case-insensitive sorted order.
+    """
+
+    usage = """
+      %prog [options]"""
+
+    def __init__(self, *args, **kw):
+        super(ListCommand, self).__init__(*args, **kw)
+
+        cmd_opts = self.cmd_opts
+
+        cmd_opts.add_option(
+            '-o', '--outdated',
+            action='store_true',
+            default=False,
+            help='List outdated packages')
+        cmd_opts.add_option(
+            '-u', '--uptodate',
+            action='store_true',
+            default=False,
+            help='List uptodate packages')
+        cmd_opts.add_option(
+            '-e', '--editable',
+            action='store_true',
+            default=False,
+            help='List editable projects.')
+        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.')
+        cmd_opts.add_option(cmdoptions.list_path())
+        cmd_opts.add_option(
+            '--pre',
+            action='store_true',
+            default=False,
+            help=("Include pre-release and development versions. By default, "
+                  "pip only finds stable versions."),
+        )
+
+        cmd_opts.add_option(
+            '--format',
+            action='store',
+            dest='list_format',
+            default="columns",
+            choices=('columns', 'freeze', 'json'),
+            help="Select the output format among: columns (default), freeze, "
+                 "or json",
+        )
+
+        cmd_opts.add_option(
+            '--not-required',
+            action='store_true',
+            dest='not_required',
+            help="List packages that are not dependencies of "
+                 "installed packages.",
+        )
+
+        cmd_opts.add_option(
+            '--exclude-editable',
+            action='store_false',
+            dest='include_editable',
+            help='Exclude editable package from output.',
+        )
+        cmd_opts.add_option(
+            '--include-editable',
+            action='store_true',
+            dest='include_editable',
+            help='Include editable package from output.',
+            default=True,
+        )
+        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, cmd_opts)
+
+    def _build_package_finder(self, options, session):
+        """
+        Create a package finder appropriate to this list command.
+        """
+        link_collector = make_link_collector(session, options=options)
+
+        # Pass allow_yanked=False to ignore yanked versions.
+        selection_prefs = SelectionPreferences(
+            allow_yanked=False,
+            allow_all_prereleases=options.pre,
+        )
+
+        return PackageFinder.create(
+            link_collector=link_collector,
+            selection_prefs=selection_prefs,
+        )
+
+    def run(self, options, args):
+        if options.outdated and options.uptodate:
+            raise CommandError(
+                "Options --outdated and --uptodate cannot be combined.")
+
+        cmdoptions.check_list_path_option(options)
+
+        packages = get_installed_distributions(
+            local_only=options.local,
+            user_only=options.user,
+            editables_only=options.editable,
+            include_editables=options.include_editable,
+            paths=options.path,
+        )
+
+        # get_not_required must be called firstly in order to find and
+        # filter out all dependencies correctly. Otherwise a package
+        # can't be identified as requirement because some parent packages
+        # could be filtered out before.
+        if options.not_required:
+            packages = self.get_not_required(packages, options)
+
+        if options.outdated:
+            packages = self.get_outdated(packages, options)
+        elif options.uptodate:
+            packages = self.get_uptodate(packages, options)
+
+        self.output_package_listing(packages, options)
+
+    def get_outdated(self, packages, options):
+        return [
+            dist for dist in self.iter_packages_latest_infos(packages, options)
+            if dist.latest_version > dist.parsed_version
+        ]
+
+    def get_uptodate(self, packages, options):
+        return [
+            dist for dist in self.iter_packages_latest_infos(packages, options)
+            if dist.latest_version == dist.parsed_version
+        ]
+
+    def get_not_required(self, packages, options):
+        dep_keys = set()
+        for dist in packages:
+            dep_keys.update(requirement.key for requirement in dist.requires())
+        return {pkg for pkg in packages if pkg.key not in dep_keys}
+
+    def iter_packages_latest_infos(self, packages, options):
+        with self._build_session(options) as session:
+            finder = self._build_package_finder(options, session)
+
+            for dist in packages:
+                typ = 'unknown'
+                all_candidates = finder.find_all_candidates(dist.key)
+                if not options.pre:
+                    # Remove prereleases
+                    all_candidates = [candidate for candidate in all_candidates
+                                      if not candidate.version.is_prerelease]
+
+                evaluator = finder.make_candidate_evaluator(
+                    project_name=dist.project_name,
+                )
+                best_candidate = evaluator.sort_best_candidate(all_candidates)
+                if best_candidate is None:
+                    continue
+
+                remote_version = best_candidate.version
+                if best_candidate.link.is_wheel:
+                    typ = 'wheel'
+                else:
+                    typ = 'sdist'
+                # This is dirty but makes the rest of the code much cleaner
+                dist.latest_version = remote_version
+                dist.latest_filetype = typ
+                yield dist
+
+    def output_package_listing(self, packages, options):
+        packages = sorted(
+            packages,
+            key=lambda dist: dist.project_name.lower(),
+        )
+        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':
+            for dist in packages:
+                if options.verbose >= 1:
+                    write_output("%s==%s (%s)", dist.project_name,
+                                 dist.version, dist.location)
+                else:
+                    write_output("%s==%s", dist.project_name, dist.version)
+        elif options.list_format == 'json':
+            write_output(format_for_json(packages, options))
+
+    def output_package_listing_columns(self, data, header):
+        # insert the header first: we need to know the size of column names
+        if len(data) > 0:
+            data.insert(0, header)
+
+        pkg_strings, sizes = tabulate(data)
+
+        # Create and add a separator.
+        if len(data) > 0:
+            pkg_strings.insert(1, " ".join(map(lambda x: '-' * x, sizes)))
+
+        for val in pkg_strings:
+            write_output(val)
+
+
+def tabulate(vals):
+    # From pfmoore on GitHub:
+    # https://github.com/pypa/pip/issues/3651#issuecomment-216932564
+    assert len(vals) > 0
+
+    sizes = [0] * max(len(x) for x in vals)
+    for row in vals:
+        sizes = [max(s, len(str(c))) for s, c in zip_longest(sizes, row)]
+
+    result = []
+    for row in vals:
+        display = " ".join([str(c).ljust(s) if c is not None else ''
+                            for s, c in zip_longest(sizes, row)])
+        result.append(display)
+
+    return result, sizes
+
+
+def format_for_columns(pkgs, options):
+    """
+    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"]
+
+    data = []
+    if options.verbose >= 1 or any(dist_is_editable(x) for x in pkgs):
+        header.append("Location")
+    if options.verbose >= 1:
+        header.append("Installer")
+
+    for proj in pkgs:
+        # if we're working on the 'outdated' list, separate out the
+        # latest_version and type
+        row = [proj.project_name, proj.version]
+
+        if running_outdated:
+            row.append(proj.latest_version)
+            row.append(proj.latest_filetype)
+
+        if options.verbose >= 1 or dist_is_editable(proj):
+            row.append(proj.location)
+        if options.verbose >= 1:
+            row.append(get_installer(proj))
+
+        data.append(row)
+
+    return data, header
+
+
+def format_for_json(packages, options):
+    data = []
+    for dist in packages:
+        info = {
+            'name': dist.project_name,
+            'version': six.text_type(dist.version),
+        }
+        if options.verbose >= 1:
+            info['location'] = dist.location
+            info['installer'] = get_installer(dist)
+        if options.outdated:
+            info['latest_version'] = six.text_type(dist.latest_version)
+            info['latest_filetype'] = dist.latest_filetype
+        data.append(info)
+    return json.dumps(data)

venv/lib/python3.8/site-packages/pip/_internal/commands/search.py

@@ -0,0 +1,145 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import logging
+import sys
+import textwrap
+from collections import OrderedDict
+
+from pip._vendor import pkg_resources
+from pip._vendor.packaging.version import parse as parse_version
+# NOTE: XMLRPC Client is not annotated in typeshed as on 2017-07-17, which is
+#       why we ignore the type on this import
+from pip._vendor.six.moves import xmlrpc_client  # type: ignore
+
+from pip._internal.cli.base_command import Command
+from pip._internal.cli.req_command import SessionCommandMixin
+from pip._internal.cli.status_codes import NO_MATCHES_FOUND, SUCCESS
+from pip._internal.exceptions import CommandError
+from pip._internal.models.index import PyPI
+from pip._internal.network.xmlrpc import PipXmlrpcTransport
+from pip._internal.utils.compat import get_terminal_size
+from pip._internal.utils.logging import indent_log
+from pip._internal.utils.misc import write_output
+
+logger = logging.getLogger(__name__)
+
+
+class SearchCommand(Command, SessionCommandMixin):
+    """Search for PyPI packages whose name or summary contains <query>."""
+
+    usage = """
+      %prog [options] <query>"""
+    ignore_require_venv = True
+
+    def __init__(self, *args, **kw):
+        super(SearchCommand, self).__init__(*args, **kw)
+        self.cmd_opts.add_option(
+            '-i', '--index',
+            dest='index',
+            metavar='URL',
+            default=PyPI.pypi_url,
+            help='Base URL of Python Package Index (default %default)')
+
+        self.parser.insert_option_group(0, self.cmd_opts)
+
+    def run(self, options, args):
+        if not args:
+            raise CommandError('Missing required argument (search query).')
+        query = args
+        pypi_hits = self.search(query, options)
+        hits = transform_hits(pypi_hits)
+
+        terminal_width = None
+        if sys.stdout.isatty():
+            terminal_width = get_terminal_size()[0]
+
+        print_results(hits, terminal_width=terminal_width)
+        if pypi_hits:
+            return SUCCESS
+        return NO_MATCHES_FOUND
+
+    def search(self, query, options):
+        index_url = options.index
+
+        session = self.get_default_session(options)
+
+        transport = PipXmlrpcTransport(index_url, session)
+        pypi = xmlrpc_client.ServerProxy(index_url, transport)
+        hits = pypi.search({'name': query, 'summary': query}, 'or')
+        return hits
+
+
+def transform_hits(hits):
+    """
+    The list from pypi is really a list of versions. We want a list of
+    packages with the list of versions stored inline. This converts the
+    list from pypi into one we can use.
+    """
+    packages = OrderedDict()
+    for hit in hits:
+        name = hit['name']
+        summary = hit['summary']
+        version = hit['version']
+
+        if name not in packages.keys():
+            packages[name] = {
+                'name': name,
+                'summary': summary,
+                'versions': [version],
+            }
+        else:
+            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
+
+    return list(packages.values())
+
+
+def print_results(hits, name_column_width=None, terminal_width=None):
+    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
+
+    installed_packages = [p.project_name for p in pkg_resources.working_set]
+    for hit in hits:
+        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 = textwrap.wrap(summary, target_width)
+                summary = ('\n' + ' ' * (name_column_width + 3)).join(summary)
+
+        line = '%-*s - %s' % (name_column_width,
+                              '%s (%s)' % (name, latest), summary)
+        try:
+            write_output(line)
+            if name in installed_packages:
+                dist = pkg_resources.get_distribution(name)
+                with indent_log():
+                    if dist.version == latest:
+                        write_output('INSTALLED: %s (latest)', dist.version)
+                    else:
+                        write_output('INSTALLED: %s', dist.version)
+                        if parse_version(latest).pre:
+                            write_output('LATEST:    %s (pre-release; install'
+                                         ' with "pip install --pre")', latest)
+                        else:
+                            write_output('LATEST:    %s', latest)
+        except UnicodeEncodeError:
+            pass
+
+
+def highest_version(versions):
+    return max(versions, key=parse_version)

venv/lib/python3.8/site-packages/pip/_internal/commands/show.py

@@ -0,0 +1,180 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import logging
+import os
+from email.parser import FeedParser
+
+from pip._vendor import pkg_resources
+from pip._vendor.packaging.utils import canonicalize_name
+
+from pip._internal.cli.base_command import Command
+from pip._internal.cli.status_codes import ERROR, SUCCESS
+from pip._internal.utils.misc import write_output
+
+logger = logging.getLogger(__name__)
+
+
+class ShowCommand(Command):
+    """
+    Show information about one or more installed packages.
+
+    The output is in RFC-compliant mail header format.
+    """
+
+    usage = """
+      %prog [options] <package> ..."""
+    ignore_require_venv = True
+
+    def __init__(self, *args, **kw):
+        super(ShowCommand, self).__init__(*args, **kw)
+        self.cmd_opts.add_option(
+            '-f', '--files',
+            dest='files',
+            action='store_true',
+            default=False,
+            help='Show the full list of installed files for each package.')
+
+        self.parser.insert_option_group(0, self.cmd_opts)
+
+    def run(self, options, args):
+        if not args:
+            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):
+            return ERROR
+        return SUCCESS
+
+
+def search_packages_info(query):
+    """
+    Gather details from installed distributions. Print distribution name,
+    version, location, and installed files. Installed files requires a
+    pip generated 'installed-files.txt' in the distributions '.egg-info'
+    directory.
+    """
+    installed = {}
+    for p in pkg_resources.working_set:
+        installed[canonicalize_name(p.project_name)] = p
+
+    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))
+
+    def get_requiring_packages(package_name):
+        canonical_name = canonicalize_name(package_name)
+        return [
+            pkg.project_name for pkg in pkg_resources.working_set
+            if canonical_name in
+               [canonicalize_name(required.name) for required in
+                pkg.requires()]
+        ]
+
+    for dist in [installed[pkg] for pkg in query_names if pkg in installed]:
+        package = {
+            'name': dist.project_name,
+            'version': dist.version,
+            'location': dist.location,
+            'requires': [dep.project_name for dep in dist.requires()],
+            'required_by': get_requiring_packages(dist.project_name)
+        }
+        file_list = None
+        metadata = None
+        if isinstance(dist, pkg_resources.DistInfoDistribution):
+            # RECORDs should be part of .dist-info metadatas
+            if dist.has_metadata('RECORD'):
+                lines = dist.get_metadata_lines('RECORD')
+                paths = [l.split(',')[0] for l in lines]
+                paths = [os.path.join(dist.location, p) for p in paths]
+                file_list = [os.path.relpath(p, dist.location) for p in paths]
+
+            if dist.has_metadata('METADATA'):
+                metadata = dist.get_metadata('METADATA')
+        else:
+            # Otherwise use pip's log for .egg-info's
+            if dist.has_metadata('installed-files.txt'):
+                paths = dist.get_metadata_lines('installed-files.txt')
+                paths = [os.path.join(dist.egg_info, p) for p in paths]
+                file_list = [os.path.relpath(p, dist.location) for p in paths]
+
+            if dist.has_metadata('PKG-INFO'):
+                metadata = dist.get_metadata('PKG-INFO')
+
+        if dist.has_metadata('entry_points.txt'):
+            entry_points = dist.get_metadata_lines('entry_points.txt')
+            package['entry_points'] = entry_points
+
+        if dist.has_metadata('INSTALLER'):
+            for line in dist.get_metadata_lines('INSTALLER'):
+                if line.strip():
+                    package['installer'] = line.strip()
+                    break
+
+        # @todo: Should pkg_resources.Distribution have a
+        # `get_pkg_info` method?
+        feed_parser = FeedParser()
+        feed_parser.feed(metadata)
+        pkg_info_dict = feed_parser.close()
+        for key in ('metadata-version', 'summary',
+                    'home-page', 'author', 'author-email', 'license'):
+            package[key] = pkg_info_dict.get(key)
+
+        # It looks like FeedParser cannot deal with repeated headers
+        classifiers = []
+        for line in metadata.splitlines():
+            if line.startswith('Classifier: '):
+                classifiers.append(line[len('Classifier: '):])
+        package['classifiers'] = classifiers
+
+        if file_list:
+            package['files'] = sorted(file_list)
+        yield package
+
+
+def print_results(distributions, list_files=False, verbose=False):
+    """
+    Print the informations from installed distributions found.
+    """
+    results_printed = False
+    for i, dist in enumerate(distributions):
+        results_printed = True
+        if i > 0:
+            write_output("---")
+
+        write_output("Name: %s", dist.get('name', ''))
+        write_output("Version: %s", dist.get('version', ''))
+        write_output("Summary: %s", dist.get('summary', ''))
+        write_output("Home-page: %s", dist.get('home-page', ''))
+        write_output("Author: %s", dist.get('author', ''))
+        write_output("Author-email: %s", dist.get('author-email', ''))
+        write_output("License: %s", dist.get('license', ''))
+        write_output("Location: %s", dist.get('location', ''))
+        write_output("Requires: %s", ', '.join(dist.get('requires', [])))
+        write_output("Required-by: %s", ', '.join(dist.get('required_by', [])))
+
+        if verbose:
+            write_output("Metadata-Version: %s",
+                         dist.get('metadata-version', ''))
+            write_output("Installer: %s", dist.get('installer', ''))
+            write_output("Classifiers:")
+            for classifier in dist.get('classifiers', []):
+                write_output("  %s", classifier)
+            write_output("Entry-points:")
+            for entry in dist.get('entry_points', []):
+                write_output("  %s", entry.strip())
+        if list_files:
+            write_output("Files:")
+            for line in dist.get('files', []):
+                write_output("  %s", line.strip())
+            if "files" not in dist:
+                write_output("Cannot locate installed-files.txt")
+    return results_printed

venv/lib/python3.8/site-packages/pip/_internal/commands/uninstall.py

@@ -0,0 +1,82 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+from pip._vendor.packaging.utils import canonicalize_name
+
+from pip._internal.cli.base_command import Command
+from pip._internal.cli.req_command import SessionCommandMixin
+from pip._internal.exceptions import InstallationError
+from pip._internal.req import parse_requirements
+from pip._internal.req.constructors import install_req_from_line
+from pip._internal.utils.misc import protect_pip_from_modification_on_windows
+
+
+class UninstallCommand(Command, SessionCommandMixin):
+    """
+    Uninstall packages.
+
+    pip is able to uninstall most installed packages. Known exceptions are:
+
+    - Pure distutils packages installed with ``python setup.py install``, which
+      leave behind no metadata to determine what files were installed.
+    - Script wrappers installed by ``python setup.py develop``.
+    """
+
+    usage = """
+      %prog [options] <package> ...
+      %prog [options] -r <requirements file> ..."""
+
+    def __init__(self, *args, **kw):
+        super(UninstallCommand, self).__init__(*args, **kw)
+        self.cmd_opts.add_option(
+            '-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.',
+        )
+        self.cmd_opts.add_option(
+            '-y', '--yes',
+            dest='yes',
+            action='store_true',
+            help="Don't ask for confirmation of uninstall deletions.")
+
+        self.parser.insert_option_group(0, self.cmd_opts)
+
+    def run(self, options, args):
+        session = self.get_default_session(options)
+
+        reqs_to_uninstall = {}
+        for name in args:
+            req = install_req_from_line(
+                name, isolated=options.isolated_mode,
+            )
+            if req.name:
+                reqs_to_uninstall[canonicalize_name(req.name)] = req
+        for filename in options.requirements:
+            for req in parse_requirements(
+                    filename,
+                    options=options,
+                    session=session):
+                if req.name:
+                    reqs_to_uninstall[canonicalize_name(req.name)] = req
+        if not reqs_to_uninstall:
+            raise InstallationError(
+                'You must give at least one requirement to %(name)s (see '
+                '"pip help %(name)s")' % dict(name=self.name)
+            )
+
+        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,
+            )
+            if uninstall_pathset:
+                uninstall_pathset.commit()

venv/lib/python3.8/site-packages/pip/_internal/commands/wheel.py

@@ -0,0 +1,197 @@
+# -*- coding: utf-8 -*-
+
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import logging
+import os
+import shutil
+
+from pip._internal.cache import WheelCache
+from pip._internal.cli import cmdoptions
+from pip._internal.cli.req_command import RequirementCommand
+from pip._internal.exceptions import CommandError, PreviousBuildDirError
+from pip._internal.req import RequirementSet
+from pip._internal.req.req_tracker import get_requirement_tracker
+from pip._internal.utils.misc import ensure_dir, normalize_path
+from pip._internal.utils.temp_dir import TempDirectory
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.wheel_builder import build, should_build_for_wheel_command
+
+if MYPY_CHECK_RUNNING:
+    from optparse import Values
+    from typing import Any, List
+
+
+logger = logging.getLogger(__name__)
+
+
+class WheelCommand(RequirementCommand):
+    """
+    Build Wheel archives for your requirements and dependencies.
+
+    Wheel is a built-package format, and offers the advantage of not
+    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.
+
+    """
+
+    usage = """
+      %prog [options] <requirement specifier> ...
+      %prog [options] -r <requirements file> ...
+      %prog [options] [-e] <vcs project url> ...
+      %prog [options] [-e] <local project path> ...
+      %prog [options] <archive url/path> ..."""
+
+    def __init__(self, *args, **kw):
+        super(WheelCommand, self).__init__(*args, **kw)
+
+        cmd_opts = self.cmd_opts
+
+        cmd_opts.add_option(
+            '-w', '--wheel-dir',
+            dest='wheel_dir',
+            metavar='dir',
+            default=os.curdir,
+            help=("Build wheels into <dir>, where the default is the "
+                  "current working directory."),
+        )
+        cmd_opts.add_option(cmdoptions.no_binary())
+        cmd_opts.add_option(cmdoptions.only_binary())
+        cmd_opts.add_option(cmdoptions.prefer_binary())
+        cmd_opts.add_option(
+            '--build-option',
+            dest='build_options',
+            metavar='options',
+            action='append',
+            help="Extra arguments to be supplied to 'setup.py bdist_wheel'.",
+        )
+        cmd_opts.add_option(cmdoptions.no_build_isolation())
+        cmd_opts.add_option(cmdoptions.use_pep517())
+        cmd_opts.add_option(cmdoptions.no_use_pep517())
+        cmd_opts.add_option(cmdoptions.constraints())
+        cmd_opts.add_option(cmdoptions.editable())
+        cmd_opts.add_option(cmdoptions.requirements())
+        cmd_opts.add_option(cmdoptions.src())
+        cmd_opts.add_option(cmdoptions.ignore_requires_python())
+        cmd_opts.add_option(cmdoptions.no_deps())
+        cmd_opts.add_option(cmdoptions.build_dir())
+        cmd_opts.add_option(cmdoptions.progress_bar())
+
+        cmd_opts.add_option(
+            '--global-option',
+            dest='global_options',
+            action='append',
+            metavar='options',
+            help="Extra global options to be supplied to the setup.py "
+            "call before the 'bdist_wheel' command.")
+
+        cmd_opts.add_option(
+            '--pre',
+            action='store_true',
+            default=False,
+            help=("Include pre-release and development versions. By default, "
+                  "pip only finds stable versions."),
+        )
+
+        cmd_opts.add_option(cmdoptions.no_clean())
+        cmd_opts.add_option(cmdoptions.require_hashes())
+
+        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, cmd_opts)
+
+    def run(self, options, args):
+        # type: (Values, List[Any]) -> None
+        cmdoptions.check_install_build_global(options)
+
+        session = self.get_default_session(options)
+
+        finder = self._build_package_finder(options, session)
+        build_delete = (not (options.no_clean or options.build_dir))
+        wheel_cache = WheelCache(options.cache_dir, options.format_control)
+
+        options.wheel_dir = normalize_path(options.wheel_dir)
+        ensure_dir(options.wheel_dir)
+
+        with get_requirement_tracker() as req_tracker, TempDirectory(
+            options.build_dir, delete=build_delete, kind="wheel"
+        ) as directory:
+
+            requirement_set = RequirementSet()
+
+            try:
+                self.populate_requirement_set(
+                    requirement_set, args, options, finder, session,
+                    wheel_cache
+                )
+
+                preparer = self.make_requirement_preparer(
+                    temp_build_dir=directory,
+                    options=options,
+                    req_tracker=req_tracker,
+                    session=session,
+                    finder=finder,
+                    wheel_download_dir=options.wheel_dir,
+                    use_user_site=False,
+                )
+
+                resolver = self.make_resolver(
+                    preparer=preparer,
+                    finder=finder,
+                    options=options,
+                    wheel_cache=wheel_cache,
+                    ignore_requires_python=options.ignore_requires_python,
+                    use_pep517=options.use_pep517,
+                )
+
+                self.trace_basic_info(finder)
+
+                resolver.resolve(requirement_set)
+
+                reqs_to_build = [
+                    r for r in requirement_set.requirements.values()
+                    if should_build_for_wheel_command(r)
+                ]
+
+                # build wheels
+                build_successes, build_failures = build(
+                    reqs_to_build,
+                    wheel_cache=wheel_cache,
+                    build_options=options.build_options or [],
+                    global_options=options.global_options or [],
+                )
+                for req in build_successes:
+                    assert req.link and req.link.is_wheel
+                    assert req.local_file_path
+                    # copy from cache to target directory
+                    try:
+                        shutil.copy(req.local_file_path, options.wheel_dir)
+                    except OSError as e:
+                        logger.warning(
+                            "Building wheel for %s failed: %s",
+                            req.name, e,
+                        )
+                        build_failures.append(req)
+                if len(build_failures) != 0:
+                    raise CommandError(
+                        "Failed to build one or more wheels"
+                    )
+            except PreviousBuildDirError:
+                options.no_clean = True
+                raise
+            finally:
+                if not options.no_clean:
+                    requirement_set.cleanup_files()
+                    wheel_cache.cleanup()

venv/lib/python3.8/site-packages/pip/_internal/configuration.py

@@ -0,0 +1,422 @@
+"""Configuration management setup
+
+Some terminology:
+- name
+  As written in config files.
+- value
+  Value associated with a name
+- key
+  Name combined with it's section (section.name)
+- variant
+  A single word describing where the configuration key-value pair came from
+"""
+
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+
+import locale
+import logging
+import os
+import sys
+
+from pip._vendor.six.moves import configparser
+
+from pip._internal.exceptions import (
+    ConfigurationError,
+    ConfigurationFileCouldNotBeLoaded,
+)
+from pip._internal.utils import appdirs
+from pip._internal.utils.compat import WINDOWS, expanduser
+from pip._internal.utils.misc import ensure_dir, enum
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import (
+        Any, Dict, Iterable, List, NewType, Optional, Tuple
+    )
+
+    RawConfigParser = configparser.RawConfigParser  # Shorthand
+    Kind = NewType("Kind", str)
+
+logger = logging.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('--'):
+        name = name[2:]  # only prefer long opts
+    return name
+
+
+def _disassemble_key(name):
+    # type: (str) -> List[str]
+    if "." not in name:
+        error_message = (
+            "Key does not contain dot separated section and key. "
+            "Perhaps you wanted to use 'global.{}' instead?"
+        ).format(name)
+        raise ConfigurationError(error_message)
+    return name.split(".", 1)
+
+
+# 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
+    ENV_VAR="env-var",  # from Environment Variables
+)
+
+
+CONFIG_BASENAME = 'pip.ini' if WINDOWS else 'pip.conf'
+
+
+def get_configuration_files():
+    # type: () -> Dict[Kind, List[str]]
+    global_config_files = [
+        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(
+        expanduser('~'),
+        'pip' if WINDOWS else '.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],
+        kinds.USER: [legacy_config_file, new_config_file],
+    }
+
+
+class Configuration(object):
+    """Handles management of configuration.
+
+    Provides an interface to accessing and managing configuration files.
+
+    This class converts provides an API that takes "section.key-name" style
+    keys and stores the value associated with it as "key-name" under the
+    section "section".
+
+    This allows for a clean interface wherein the both the section and the
+    key-name are preserved in an easy to manage form in the configuration files
+    and the data stored is also nice.
+    """
+
+    def __init__(self, isolated, load_only=None):
+        # type: (bool, Kind) -> None
+        super(Configuration, self).__init__()
+
+        _valid_load_only = [kinds.USER, kinds.GLOBAL, kinds.SITE, None]
+        if load_only not in _valid_load_only:
+            raise ConfigurationError(
+                "Got invalid value for load_only - should be one of {}".format(
+                    ", ".join(map(repr, _valid_load_only[:-1]))
+                )
+            )
+        self.isolated = isolated  # type: bool
+        self.load_only = load_only  # type: Optional[Kind]
+
+        # The order here determines the override order.
+        self._override_order = [
+            kinds.GLOBAL, kinds.USER, kinds.SITE, kinds.ENV, kinds.ENV_VAR
+        ]
+
+        self._ignore_env_names = ["version", "help"]
+
+        # Because we keep track of where we got the data from
+        self._parsers = {
+            variant: [] for variant in self._override_order
+        }  # type: Dict[Kind, List[Tuple[str, RawConfigParser]]]
+        self._config = {
+            variant: {} for variant in self._override_order
+        }  # type: Dict[Kind, Dict[str, Any]]
+        self._modified_parsers = []  # type: List[Tuple[str, RawConfigParser]]
+
+    def load(self):
+        # type: () -> 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"
+
+        try:
+            return self._get_parser_to_modify()[0]
+        except IndexError:
+            return None
+
+    def items(self):
+        # type: () -> 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.
+        """
+        try:
+            return self._dictionary[key]
+        except KeyError:
+            raise ConfigurationError("No such key - {}".format(key))
+
+    def set_value(self, key, value):
+        # type: (str, Any) -> None
+        """Modify a value in the configuration.
+        """
+        self._ensure_have_load_only()
+
+        fname, parser = self._get_parser_to_modify()
+
+        if parser is not None:
+            section, name = _disassemble_key(key)
+
+            # Modify the parser and the configuration
+            if not parser.has_section(section):
+                parser.add_section(section)
+            parser.set(section, name, value)
+
+        self._config[self.load_only][key] = value
+        self._mark_as_modified(fname, parser)
+
+    def unset_value(self, key):
+        # type: (str) -> None
+        """Unset a value in the configuration.
+        """
+        self._ensure_have_load_only()
+
+        if key not in self._config[self.load_only]:
+            raise ConfigurationError("No such key - {}".format(key))
+
+        fname, parser = self._get_parser_to_modify()
+
+        if parser is not None:
+            section, name = _disassemble_key(key)
+
+            # Remove the key in the parser
+            modified_something = False
+            if parser.has_section(section):
+                # Returns whether the option was removed or not
+                modified_something = parser.remove_option(section, name)
+
+            if modified_something:
+                # name removed from parser, section may now be empty
+                section_iter = iter(parser.items(section))
+                try:
+                    val = next(section_iter)
+                except StopIteration:
+                    val = None
+
+                if val is None:
+                    parser.remove_section(section)
+
+                self._mark_as_modified(fname, parser)
+            else:
+                raise ConfigurationError(
+                    "Fatal Internal error [id=1]. Please report as a bug."
+                )
+
+        del self._config[self.load_only][key]
+
+    def save(self):
+        # type: () -> None
+        """Save the current in-memory state.
+        """
+        self._ensure_have_load_only()
+
+        for fname, parser in self._modified_parsers:
+            logger.info("Writing to %s", fname)
+
+            # Ensure directory exists.
+            ensure_dir(os.path.dirname(fname))
+
+            with open(fname, "w") as f:
+                parser.write(f)
+
+    #
+    # Private routines
+    #
+
+    def _ensure_have_load_only(self):
+        # type: () -> 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.
+        """
+        # NOTE: Dictionaries are not populated if not loaded. So, conditionals
+        #       are not needed here.
+        retval = {}
+
+        for variant in self._override_order:
+            retval.update(self._config[variant])
+
+        return retval
+
+    def _load_config_files(self):
+        # type: () -> None
+        """Loads configuration from configuration files
+        """
+        config_files = dict(self._iter_config_files())
+        if config_files[kinds.ENV][0:1] == [os.devnull]:
+            logger.debug(
+                "Skipping loading configuration files due to "
+                "environment's PIP_CONFIG_FILE being os.devnull"
+            )
+            return
+
+        for variant, files in config_files.items():
+            for fname in files:
+                # 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
+                    )
+                    continue
+
+                parser = self._load_file(variant, fname)
+
+                # 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)
+        parser = self._construct_parser(fname)
+
+        for section in parser.sections():
+            items = parser.items(section)
+            self._config[variant].update(self._normalized_keys(section, items))
+
+        return parser
+
+    def _construct_parser(self, fname):
+        # type: (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):
+            try:
+                parser.read(fname)
+            except UnicodeDecodeError:
+                # See https://github.com/pypa/pip/issues/4963
+                raise ConfigurationFileCouldNotBeLoaded(
+                    reason="contains invalid {} characters".format(
+                        locale.getpreferredencoding(False)
+                    ),
+                    fname=fname,
+                )
+            except configparser.Error as error:
+                # See https://github.com/pypa/pip/issues/4893
+                raise ConfigurationFileCouldNotBeLoaded(error=error)
+        return parser
+
+    def _load_environment_vars(self):
+        # type: () -> 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]
+        """Normalizes items to construct a dictionary with normalized keys.
+
+        This routine is where the names become keys and are made the same
+        regardless of source - configuration files or environment.
+        """
+        normalized = {}
+        for name, val in items:
+            key = section + "." + _normalize_name(name)
+            normalized[key] = val
+        return normalized
+
+    def _get_environ_vars(self):
+        # type: () -> Iterable[Tuple[str, str]]
+        """Returns a generator with all environmental vars with prefix PIP_"""
+        for key, val in os.environ.items():
+            should_be_yielded = (
+                key.startswith("PIP_") and
+                key[4:].lower() not in self._ignore_env_names
+            )
+            if should_be_yielded:
+                yield key[4:].lower(), val
+
+    # XXX: This is patched in the tests.
+    def _iter_config_files(self):
+        # type: () -> Iterable[Tuple[Kind, List[str]]]
+        """Yields variant and configuration files associated with it.
+
+        This should be treated like items of a dictionary.
+        """
+        # SMELL: Move the conditions out of this function
+
+        # environment variables have the lowest priority
+        config_file = os.environ.get('PIP_CONFIG_FILE', None)
+        if config_file is not None:
+            yield kinds.ENV, [config_file]
+        else:
+            yield kinds.ENV, []
+
+        config_files = get_configuration_files()
+
+        # at the base we have any global configuration
+        yield kinds.GLOBAL, config_files[kinds.GLOBAL]
+
+        # per-user configuration next
+        should_load_user_config = not self.isolated and not (
+            config_file and os.path.exists(config_file)
+        )
+        if should_load_user_config:
+            # The legacy config file is overridden by the new config file
+            yield kinds.USER, config_files[kinds.USER]
+
+        # finally virtualenv configuration first trumping others
+        yield kinds.SITE, config_files[kinds.SITE]
+
+    def _get_parser_to_modify(self):
+        # type: () -> Tuple[str, RawConfigParser]
+        # Determine which parser to modify
+        parsers = self._parsers[self.load_only]
+        if not parsers:
+            # This should not happen if everything works correctly.
+            raise ConfigurationError(
+                "Fatal Internal error [id=2]. Please report as a bug."
+            )
+
+        # Use the highest priority parser.
+        return parsers[-1]
+
+    # XXX: This is patched in the tests.
+    def _mark_as_modified(self, fname, parser):
+        # type: (str, RawConfigParser) -> None
+        file_parser_tuple = (fname, parser)
+        if file_parser_tuple not in self._modified_parsers:
+            self._modified_parsers.append(file_parser_tuple)

venv/lib/python3.8/site-packages/pip/_internal/distributions/__init__.py

@@ -0,0 +1,24 @@
+from pip._internal.distributions.sdist import SourceDistribution
+from pip._internal.distributions.wheel import WheelDistribution
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from pip._internal.distributions.base import AbstractDistribution
+    from pip._internal.req.req_install import InstallRequirement
+
+
+def make_distribution_for_install_requirement(install_req):
+    # type: (InstallRequirement) -> AbstractDistribution
+    """Returns a Distribution for the given InstallRequirement
+    """
+    # Editable requirements will always be source distributions. They use the
+    # legacy logic until we create a modern standard for them.
+    if install_req.editable:
+        return SourceDistribution(install_req)
+
+    # If it's a wheel, it's a WheelDistribution
+    if install_req.is_wheel:
+        return WheelDistribution(install_req)
+
+    # Otherwise, a SourceDistribution
+    return SourceDistribution(install_req)

venv/lib/python3.8/site-packages/pip/_internal/distributions/base.py

@@ -0,0 +1,45 @@
+import abc
+
+from pip._vendor.six import add_metaclass
+
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Optional
+
+    from pip._vendor.pkg_resources import Distribution
+    from pip._internal.req import InstallRequirement
+    from pip._internal.index.package_finder import PackageFinder
+
+
+@add_metaclass(abc.ABCMeta)
+class AbstractDistribution(object):
+    """A base class for handling installable artifacts.
+
+    The requirements for anything installable are as follows:
+
+     - we must be able to determine the requirement name
+       (or we can't correctly handle the non-upgrade case).
+
+     - for packages with setup requirements, we must also be able
+       to determine their requirements without installing additional
+       packages (for the same reason as run-time dependencies)
+
+     - we must be able to create a Distribution object exposing the
+       above metadata.
+    """
+
+    def __init__(self, req):
+        # type: (InstallRequirement) -> None
+        super(AbstractDistribution, self).__init__()
+        self.req = req
+
+    @abc.abstractmethod
+    def get_pkg_resources_distribution(self):
+        # type: () -> Optional[Distribution]
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    def prepare_distribution_metadata(self, finder, build_isolation):
+        # type: (PackageFinder, bool) -> None
+        raise NotImplementedError()

venv/lib/python3.8/site-packages/pip/_internal/distributions/installed.py

@@ -0,0 +1,24 @@
+from pip._internal.distributions.base import AbstractDistribution
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Optional
+
+    from pip._vendor.pkg_resources import Distribution
+    from pip._internal.index.package_finder import PackageFinder
+
+
+class InstalledDistribution(AbstractDistribution):
+    """Represents an installed package.
+
+    This does not need any preparation as the required information has already
+    been computed.
+    """
+
+    def get_pkg_resources_distribution(self):
+        # type: () -> Optional[Distribution]
+        return self.req.satisfied_by
+
+    def prepare_distribution_metadata(self, finder, build_isolation):
+        # type: (PackageFinder, bool) -> None
+        pass

venv/lib/python3.8/site-packages/pip/_internal/distributions/sdist.py

@@ -0,0 +1,104 @@
+import logging
+
+from pip._internal.build_env import BuildEnvironment
+from pip._internal.distributions.base import AbstractDistribution
+from pip._internal.exceptions import InstallationError
+from pip._internal.utils.subprocess import runner_with_spinner_message
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Set, Tuple
+
+    from pip._vendor.pkg_resources import Distribution
+    from pip._internal.index.package_finder import PackageFinder
+
+
+logger = logging.getLogger(__name__)
+
+
+class SourceDistribution(AbstractDistribution):
+    """Represents a source distribution.
+
+    The preparation step for these needs metadata for the packages to be
+    generated, either using PEP 517 or using the legacy `setup.py egg_info`.
+    """
+
+    def get_pkg_resources_distribution(self):
+        # type: () -> Distribution
+        return self.req.get_dist()
+
+    def prepare_distribution_metadata(self, finder, build_isolation):
+        # type: (PackageFinder, bool) -> None
+        # Load pyproject.toml, to determine whether PEP 517 is to be used
+        self.req.load_pyproject_toml()
+
+        # 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)
+
+        self.req.prepare_metadata()
+
+    def _setup_isolation(self, finder):
+        # type: (PackageFinder) -> None
+        def _raise_conflicts(conflicting_with, conflicting_reqs):
+            # type: (str, 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(
+                    '{} is incompatible with {}'.format(installed, wanted)
+                    for installed, wanted in sorted(conflicting)
+                )
+            )
+            raise InstallationError(error_message)
+
+        # Isolate in a BuildEnvironment and install the build-time
+        # requirements.
+        pyproject_requires = self.req.pyproject_requires
+        assert pyproject_requires is not None
+
+        self.req.build_env = BuildEnvironment()
+        self.req.build_env.install_requirements(
+            finder, pyproject_requires, 'overlay',
+            "Installing 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)
+        if missing:
+            logger.warning(
+                "Missing build requirements in pyproject.toml for %s.",
+                self.req,
+            )
+            logger.warning(
+                "The project does not specify a build backend, and "
+                "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.
+        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()
+
+        conflicting, missing = self.req.build_env.check_requirements(reqs)
+        if conflicting:
+            _raise_conflicts("the backend dependencies", conflicting)
+        self.req.build_env.install_requirements(
+            finder, missing, 'normal',
+            "Installing backend dependencies"
+        )

venv/lib/python3.8/site-packages/pip/_internal/distributions/wheel.py

@@ -0,0 +1,36 @@
+from zipfile import ZipFile
+
+from pip._internal.distributions.base import AbstractDistribution
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.wheel import pkg_resources_distribution_for_wheel
+
+if MYPY_CHECK_RUNNING:
+    from pip._vendor.pkg_resources import Distribution
+    from pip._internal.index.package_finder import PackageFinder
+
+
+class WheelDistribution(AbstractDistribution):
+    """Represents a wheel distribution.
+
+    This does not need any preparation as wheels can be directly unpacked.
+    """
+
+    def get_pkg_resources_distribution(self):
+        # type: () -> Distribution
+        """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
+            )
+
+    def prepare_distribution_metadata(self, finder, build_isolation):
+        # type: (PackageFinder, bool) -> None
+        pass

venv/lib/python3.8/site-packages/pip/_internal/exceptions.py

@@ -0,0 +1,308 @@
+"""Exceptions used throughout package"""
+
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+from itertools import chain, groupby, repeat
+
+from pip._vendor.six import iteritems
+
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Optional
+    from pip._vendor.pkg_resources import Distribution
+    from pip._internal.req.req_install import InstallRequirement
+
+
+class PipError(Exception):
+    """Base pip exception"""
+
+
+class ConfigurationError(PipError):
+    """General exception in configuration"""
+
+
+class InstallationError(PipError):
+    """General exception during installation"""
+
+
+class UninstallationError(PipError):
+    """General exception during uninstallation"""
+
+
+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").
+    """
+
+    def __init__(self, dist, metadata_name):
+        # type: (Distribution, str) -> None
+        """
+        :param dist: A Distribution object.
+        :param metadata_name: The name of the metadata being accessed
+            (can be "METADATA" or "PKG-INFO").
+        """
+        self.dist = dist
+        self.metadata_name = metadata_name
+
+    def __str__(self):
+        # type: () -> 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,
+            )
+        )
+
+
+class DistributionNotFound(InstallationError):
+    """Raised when a distribution cannot be found to satisfy a requirement"""
+
+
+class RequirementsFileParseError(InstallationError):
+    """Raised when a general error occurs parsing a requirements file line."""
+
+
+class BestVersionAlreadyInstalled(PipError):
+    """Raised when the most up-to-date version of a package is already
+    installed."""
+
+
+class BadCommand(PipError):
+    """Raised when virtualenv or a command is not found"""
+
+
+class CommandError(PipError):
+    """Raised when there is an error in command-line arguments"""
+
+
+class PreviousBuildDirError(PipError):
+    """Raised when there's a previous conflicting build directory"""
+
+
+class InvalidWheelFilename(InstallationError):
+    """Invalid wheel filename."""
+
+
+class UnsupportedWheel(InstallationError):
+    """Unsupported wheel."""
+
+
+class HashErrors(InstallationError):
+    """Multiple HashError instances rolled into one for reporting"""
+
+    def __init__(self):
+        self.errors = []
+
+    def append(self, error):
+        self.errors.append(error)
+
+    def __str__(self):
+        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)
+
+    def __nonzero__(self):
+        return bool(self.errors)
+
+    def __bool__(self):
+        return self.__nonzero__()
+
+
+class HashError(InstallationError):
+    """
+    A failure to verify a package against known-good hashes
+
+    :cvar order: An int sorting hash exception classes by difficulty of
+        recovery (lower being harder), so the user doesn't bother fretting
+        about unpinned packages when he has deeper issues, like VCS
+        dependencies, to deal with. Also keeps error reports in a
+        deterministic order.
+    :cvar head: A section heading for display above potentially many
+        exceptions of this kind
+    :ivar req: The InstallRequirement that triggered this error. This is
+        pasted on after the exception is instantiated, because it's not
+        typically available earlier.
+
+    """
+    req = None  # type: Optional[InstallRequirement]
+    head = ''
+
+    def body(self):
+        """Return a summary of me for display under the heading.
+
+        This default implementation simply prints a description of the
+        triggering requirement.
+
+        :param req: The InstallRequirement that provoked this error, with
+            populate_link() having already been called
+
+        """
+        return '    %s' % self._requirement_name()
+
+    def __str__(self):
+        return '%s\n%s' % (self.head, self.body())
+
+    def _requirement_name(self):
+        """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'
+
+
+class VcsHashUnsupported(HashError):
+    """A hash was provided for a version-control-system-based requirement, but
+    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:")
+
+
+class DirectoryUrlHashUnsupported(HashError):
+    """A hash was provided for a version-control-system-based requirement, but
+    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:")
+
+
+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.)')
+
+    def __init__(self, gotten_hash):
+        """
+        :param gotten_hash: The hash of the (possibly malicious) archive we
+            just downloaded
+        """
+        self.gotten_hash = gotten_hash
+
+    def body(self):
+        # Dodge circular import.
+        from pip._internal.utils.hashes import FAVORITE_HASH
+
+        package = None
+        if self.req:
+            # 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 '    %s --hash=%s:%s' % (package or 'unknown package',
+                                        FAVORITE_HASH,
+                                        self.gotten_hash)
+
+
+class HashUnpinned(HashError):
+    """A requirement had a hash specified but was not pinned to a specific
+    version."""
+
+    order = 3
+    head = ('In --require-hashes mode, all requirements must have their '
+            'versions pinned with ==. These do not:')
+
+
+class HashMismatch(HashError):
+    """
+    Distribution file hash values don't match.
+
+    :ivar package_name: The name of the package that triggered the hash
+        mismatch. Feel free to write to this after the exception is raise to
+        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):
+        """
+        :param allowed: A dict of algorithm names pointing to lists of allowed
+            hex digests
+        :param gots: A dict of algorithm names pointing to hashes we
+            actually got from the files under suspicion
+        """
+        self.allowed = allowed
+        self.gots = gots
+
+    def body(self):
+        return '    %s:\n%s' % (self._requirement_name(),
+                                self._hash_comparison())
+
+    def _hash_comparison(self):
+        """
+        Return a comparison of actual and expected hash values.
+
+        Example::
+
+               Expected sha256 abcdeabcdeabcdeabcdeabcdeabcdeabcdeabcdeabcde
+                            or 123451234512345123451234512345123451234512345
+                    Got        bcdefbcdefbcdefbcdefbcdefbcdefbcdefbcdefbcdef
+
+        """
+        def hash_then_or(hash_name):
+            # 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'))
+
+        lines = []
+        for hash_name, expecteds in iteritems(self.allowed):
+            prefix = hash_then_or(hash_name)
+            lines.extend(('        Expected %s %s' % (next(prefix), e))
+                         for e in expecteds)
+            lines.append('             Got        %s\n' %
+                         self.gots[hash_name].hexdigest())
+        return '\n'.join(lines)
+
+
+class UnsupportedPythonVersion(InstallationError):
+    """Unsupported python version according to Requires-Python package
+    metadata."""
+
+
+class ConfigurationFileCouldNotBeLoaded(ConfigurationError):
+    """When there are errors while loading a configuration file
+    """
+
+    def __init__(self, reason="could not be loaded", fname=None, error=None):
+        super(ConfigurationFileCouldNotBeLoaded, self).__init__(error)
+        self.reason = reason
+        self.fname = fname
+        self.error = error
+
+    def __str__(self):
+        if self.fname is not None:
+            message_part = " in {}.".format(self.fname)
+        else:
+            assert self.error is not None
+            message_part = ".\n{}\n".format(self.error.message)
+        return "Configuration file {}{}".format(self.reason, message_part)

venv/lib/python3.8/site-packages/pip/_internal/index/__init__.py

@@ -0,0 +1,2 @@
+"""Index interaction code
+"""

venv/lib/python3.8/site-packages/pip/_internal/index/collector.py

@@ -0,0 +1,544 @@
+"""
+The main purpose of this module is to expose LinkCollector.collect_links().
+"""
+
+import cgi
+import itertools
+import logging
+import mimetypes
+import os
+from collections import OrderedDict
+
+from pip._vendor import html5lib, requests
+from pip._vendor.distlib.compat import unescape
+from pip._vendor.requests.exceptions import HTTPError, RetryError, SSLError
+from pip._vendor.six.moves.urllib import parse as urllib_parse
+from pip._vendor.six.moves.urllib import request as urllib_request
+
+from pip._internal.models.link import Link
+from pip._internal.utils.filetypes import ARCHIVE_EXTENSIONS
+from pip._internal.utils.misc import redact_auth_from_url
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.urls import path_to_url, url_to_path
+from pip._internal.vcs import is_url, vcs
+
+if MYPY_CHECK_RUNNING:
+    from typing import (
+        Callable, Iterable, List, MutableMapping, Optional, Sequence, Tuple,
+        Union,
+    )
+    import xml.etree.ElementTree
+
+    from pip._vendor.requests import Response
+
+    from pip._internal.models.search_scope import SearchScope
+    from pip._internal.network.session import PipSession
+
+    HTMLElement = xml.etree.ElementTree.Element
+    ResponseHeaders = MutableMapping[str, str]
+
+
+logger = logging.getLogger(__name__)
+
+
+def _match_vcs_scheme(url):
+    # type: (str) -> Optional[str]
+    """Look for VCS schemes in the URL.
+
+    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 '+:':
+            return scheme
+    return None
+
+
+def _is_url_like_archive(url):
+    # type: (str) -> bool
+    """Return whether the URL looks like an archive.
+    """
+    filename = Link(url).filename
+    for bad_ext in ARCHIVE_EXTENSIONS:
+        if filename.endswith(bad_ext):
+            return True
+    return False
+
+
+class _NotHTML(Exception):
+    def __init__(self, content_type, request_desc):
+        # type: (str, str) -> None
+        super(_NotHTML, self).__init__(content_type, request_desc)
+        self.content_type = content_type
+        self.request_desc = request_desc
+
+
+def _ensure_html_header(response):
+    # type: (Response) -> None
+    """Check the Content-Type header to ensure the response contains HTML.
+
+    Raises `_NotHTML` if the content type is not text/html.
+    """
+    content_type = response.headers.get("Content-Type", "")
+    if not content_type.lower().startswith("text/html"):
+        raise _NotHTML(content_type, response.request.method)
+
+
+class _NotHTTP(Exception):
+    pass
+
+
+def _ensure_html_response(url, session):
+    # type: (str, PipSession) -> None
+    """Send a HEAD request to the URL, and ensure the response contains HTML.
+
+    Raises `_NotHTTP` if the URL is not available for a HEAD request, or
+    `_NotHTML` if the content type is not text/html.
+    """
+    scheme, netloc, path, query, fragment = urllib_parse.urlsplit(url)
+    if scheme not in {'http', 'https'}:
+        raise _NotHTTP()
+
+    resp = session.head(url, allow_redirects=True)
+    resp.raise_for_status()
+
+    _ensure_html_header(resp)
+
+
+def _get_html_response(url, session):
+    # type: (str, PipSession) -> Response
+    """Access an HTML page 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.
+    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.
+    """
+    if _is_url_like_archive(url):
+        _ensure_html_response(url, session=session)
+
+    logger.debug('Getting page %s', redact_auth_from_url(url))
+
+    resp = session.get(
+        url,
+        headers={
+            "Accept": "text/html",
+            # We don't want to blindly returned cached data for
+            # /simple/, because authors generally expecting that
+            # twine upload && pip install will function, but if
+            # they've done a pip install in the last ~10 minutes
+            # it won't. Thus by setting this to zero we will not
+            # blindly use any cached data, however the benefit of
+            # using max-age=0 instead of no-cache, is that we will
+            # still support conditional requests, so we will still
+            # minimize traffic sent in cases where the page hasn't
+            # changed at all, we will just always incur the round
+            # trip for the conditional GET now instead of only
+            # once per 10 minutes.
+            # For more information, please see pypa/pip#5670.
+            "Cache-Control": "max-age=0",
+        },
+    )
+    resp.raise_for_status()
+
+    # 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)
+
+    return resp
+
+
+def _get_encoding_from_headers(headers):
+    # type: (ResponseHeaders) -> Optional[str]
+    """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']
+    return None
+
+
+def _determine_base_url(document, page_url):
+    # type: (HTMLElement, 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_link(url):
+    # type: (str) -> str
+    """Makes sure a link is fully encoded.  That is, if a ' ' shows up in
+    the link, it will be rewritten to %20 (while not over-quoting
+    % or other characters)."""
+    # Split the URL into parts according to the general structure
+    # `scheme://netloc/path;parameters?query#fragment`. Note that the
+    # `netloc` can be empty and the URI will then refer to a local
+    # filesystem path.
+    result = urllib_parse.urlparse(url)
+    # In both cases below we unquote prior to quoting to make sure
+    # nothing is double quoted.
+    if result.netloc == "":
+        # 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.
+        path = urllib_request.pathname2url(
+            urllib_request.url2pathname(result.path))
+    else:
+        # In addition to the `/` character we protect `@` so that
+        # revision strings in VCS URLs are properly parsed.
+        path = urllib_parse.quote(urllib_parse.unquote(result.path), safe="/@")
+    return urllib_parse.urlunparse(result._replace(path=path))
+
+
+def _create_link_from_element(
+    anchor,    # type: HTMLElement
+    page_url,  # type: str
+    base_url,  # type: str
+):
+    # type: (...) -> 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 = unescape(pyrequire) if pyrequire else None
+
+    yanked_reason = anchor.get('data-yanked')
+    if yanked_reason:
+        # This is a unicode string in Python 2 (and 3).
+        yanked_reason = unescape(yanked_reason)
+
+    link = Link(
+        url,
+        comes_from=page_url,
+        requires_python=pyrequire,
+        yanked_reason=yanked_reason,
+    )
+
+    return link
+
+
+def parse_links(page):
+    # type: (HTMLPage) -> Iterable[Link]
+    """
+    Parse an HTML document, and yield its anchor elements as Link objects.
+    """
+    document = html5lib.parse(
+        page.content,
+        transport_encoding=page.encoding,
+        namespaceHTMLElements=False,
+    )
+
+    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,
+        )
+        if link is None:
+            continue
+        yield link
+
+
+class HTMLPage(object):
+    """Represents one page, along with its URL"""
+
+    def __init__(
+        self,
+        content,   # type: bytes
+        encoding,  # type: Optional[str]
+        url,       # type: str
+    ):
+        # type: (...) -> None
+        """
+        :param encoding: the encoding to decode the given content.
+        :param url: the URL from which the HTML was downloaded.
+        """
+        self.content = content
+        self.encoding = encoding
+        self.url = url
+
+    def __str__(self):
+        # type: () -> str
+        return redact_auth_from_url(self.url)
+
+
+def _handle_get_page_fail(
+    link,  # type: Link
+    reason,  # type: Union[str, Exception]
+    meth=None  # type: Optional[Callable[..., None]]
+):
+    # type: (...) -> None
+    if meth is None:
+        meth = logger.debug
+    meth("Could not fetch URL %s: %s - skipping", link, reason)
+
+
+def _make_html_page(response):
+    # type: (Response) -> HTMLPage
+    encoding = _get_encoding_from_headers(response.headers)
+    return HTMLPage(response.content, encoding=encoding, url=response.url)
+
+
+def _get_html_page(link, session=None):
+    # type: (Link, Optional[PipSession]) -> Optional[HTMLPage]
+    if session is None:
+        raise TypeError(
+            "_get_html_page() missing 1 required keyword argument: 'session'"
+        )
+
+    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.debug('Cannot look at %s URL %s', 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))):
+        # 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)
+
+    try:
+        resp = _get_html_response(url, session=session)
+    except _NotHTTP:
+        logger.debug(
+            'Skipping page %s because it looks like an archive, and cannot '
+            'be checked by HEAD.', link,
+        )
+    except _NotHTML as exc:
+        logger.debug(
+            'Skipping page %s because the %s request got Content-Type: %s',
+            link, exc.request_desc, exc.content_type,
+        )
+    except HTTPError as exc:
+        _handle_get_page_fail(link, exc)
+    except RetryError as exc:
+        _handle_get_page_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)
+    except requests.ConnectionError as exc:
+        _handle_get_page_fail(link, "connection error: %s" % exc)
+    except requests.Timeout:
+        _handle_get_page_fail(link, "timed out")
+    else:
+        return _make_html_page(resp)
+    return None
+
+
+def _remove_duplicate_links(links):
+    # type: (Iterable[Link]) -> List[Link]
+    """
+    Return a list of links, with duplicates removed and ordering preserved.
+    """
+    # We preserve the ordering when removing duplicates because we can.
+    return list(OrderedDict.fromkeys(links))
+
+
+def group_locations(locations, expand_dir=False):
+    # type: (Sequence[str], bool) -> Tuple[List[str], List[str]]
+    """
+    Divide a list of locations into two groups: "files" (archives) and "urls."
+
+    :return: A pair of lists (files, urls).
+    """
+    files = []
+    urls = []
+
+    # puts the url for the given file path into the appropriate list
+    def sort_path(path):
+        # type: (str) -> None
+        url = path_to_url(path)
+        if mimetypes.guess_type(url, strict=False)[0] == 'text/html':
+            urls.append(url)
+        else:
+            files.append(url)
+
+    for url in locations:
+
+        is_local_path = os.path.exists(url)
+        is_file_url = url.startswith('file:')
+
+        if is_local_path or is_file_url:
+            if is_local_path:
+                path = url
+            else:
+                path = url_to_path(url)
+            if os.path.isdir(path):
+                if expand_dir:
+                    path = os.path.realpath(path)
+                    for item in os.listdir(path):
+                        sort_path(os.path.join(path, item))
+                elif is_file_url:
+                    urls.append(url)
+                else:
+                    logger.warning(
+                        "Path '{0}' is ignored: "
+                        "it is a directory.".format(path),
+                    )
+            elif os.path.isfile(path):
+                sort_path(path)
+            else:
+                logger.warning(
+                    "Url '%s' is ignored: it is neither a file "
+                    "nor a directory.", url,
+                )
+        elif is_url(url):
+            # Only add url with clear scheme
+            urls.append(url)
+        else:
+            logger.warning(
+                "Url '%s' is ignored. It is either a non-existing "
+                "path or lacks a specific scheme.", url,
+            )
+
+    return files, urls
+
+
+class CollectedLinks(object):
+
+    """
+    Encapsulates the return value of a call to LinkCollector.collect_links().
+
+    The return value includes both URLs to project pages containing package
+    links, as well as individual package Link objects collected from other
+    sources.
+
+    This info is stored separately as:
+
+    (1) links from the configured file locations,
+    (2) links from the configured find_links, and
+    (3) urls to HTML project pages, as described by the PEP 503 simple
+        repository API.
+    """
+
+    def __init__(
+        self,
+        files,         # type: List[Link]
+        find_links,    # type: List[Link]
+        project_urls,  # type: List[Link]
+    ):
+        # type: (...) -> None
+        """
+        :param files: Links from file locations.
+        :param find_links: Links from find_links.
+        :param project_urls: URLs to HTML project pages, as described by
+            the PEP 503 simple repository API.
+        """
+        self.files = files
+        self.find_links = find_links
+        self.project_urls = project_urls
+
+
+class LinkCollector(object):
+
+    """
+    Responsible for collecting Link objects from all configured locations,
+    making network requests as needed.
+
+    The class's main method is its collect_links() method.
+    """
+
+    def __init__(
+        self,
+        session,       # type: PipSession
+        search_scope,  # type: SearchScope
+    ):
+        # type: (...) -> None
+        self.search_scope = search_scope
+        self.session = session
+
+    @property
+    def find_links(self):
+        # type: () -> List[str]
+        return self.search_scope.find_links
+
+    def fetch_page(self, location):
+        # type: (Link) -> Optional[HTMLPage]
+        """
+        Fetch an HTML page containing package links.
+        """
+        return _get_html_page(location, session=self.session)
+
+    def collect_links(self, project_name):
+        # type: (str) -> CollectedLinks
+        """Find all available links for the given project name.
+
+        :return: All the Link objects (unfiltered), as a CollectedLinks object.
+        """
+        search_scope = self.search_scope
+        index_locations = search_scope.get_index_urls_locations(project_name)
+        index_file_loc, index_url_loc = group_locations(index_locations)
+        fl_file_loc, fl_url_loc = group_locations(
+            self.find_links, expand_dir=True,
+        )
+
+        file_links = [
+            Link(url) for url in itertools.chain(index_file_loc, fl_file_loc)
+        ]
+
+        # We trust every directly linked archive in find_links
+        find_link_links = [Link(url, '-f') for url in self.find_links]
+
+        # We trust every url that the user has given us whether it was given
+        # via --index-url or --find-links.
+        # We want to filter out anything that does not have a secure origin.
+        url_locations = [
+            link for link in itertools.chain(
+                (Link(url) for url in index_url_loc),
+                (Link(url) for url in fl_url_loc),
+            )
+            if self.session.is_secure_origin(link)
+        ]
+
+        url_locations = _remove_duplicate_links(url_locations)
+        lines = [
+            '{} location(s) to search for versions of {}:'.format(
+                len(url_locations), project_name,
+            ),
+        ]
+        for link in url_locations:
+            lines.append('* {}'.format(link))
+        logger.debug('\n'.join(lines))
+
+        return CollectedLinks(
+            files=file_links,
+            find_links=find_link_links,
+            project_urls=url_locations,
+        )

venv/lib/python3.8/site-packages/pip/_internal/legacy_resolve.py

@@ -0,0 +1,430 @@
+"""Dependency Resolution
+
+The dependency resolution in pip is performed as follows:
+
+for top-level requirements:
+    a. only one spec allowed per project, regardless of conflicts or not.
+       otherwise a "double requirement" exception is raised
+    b. they override sub-dependency requirements.
+for sub-dependencies
+    a. "first found, wins" (where the order is breadth first)
+"""
+
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+# mypy: disallow-untyped-defs=False
+
+import logging
+import sys
+from collections import defaultdict
+from itertools import chain
+
+from pip._vendor.packaging import specifiers
+
+from pip._internal.exceptions import (
+    BestVersionAlreadyInstalled,
+    DistributionNotFound,
+    HashError,
+    HashErrors,
+    UnsupportedPythonVersion,
+)
+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.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Callable, DefaultDict, List, Optional, Set, Tuple
+    from pip._vendor import pkg_resources
+
+    from pip._internal.distributions import AbstractDistribution
+    from pip._internal.index.package_finder import PackageFinder
+    from pip._internal.operations.prepare import RequirementPreparer
+    from pip._internal.req.req_install import InstallRequirement
+    from pip._internal.req.req_set import RequirementSet
+
+    InstallRequirementProvider = Callable[
+        [str, InstallRequirement], InstallRequirement
+    ]
+    DiscoveredDependencies = DefaultDict[str, List[InstallRequirement]]
+
+logger = logging.getLogger(__name__)
+
+
+def _check_dist_requires_python(
+    dist,  # type: pkg_resources.Distribution
+    version_info,  # type: Tuple[int, int, int]
+    ignore_requires_python=False,  # type: bool
+):
+    # type: (...) -> None
+    """
+    Check whether the given Python version is compatible with a distribution's
+    "Requires-Python" value.
+
+    :param version_info: A 3-tuple of ints representing the Python
+        major-minor-micro version to check.
+    :param ignore_requires_python: Whether to ignore the "Requires-Python"
+        value if the given Python version isn't compatible.
+
+    :raises UnsupportedPythonVersion: When the given Python version isn't
+        compatible.
+    """
+    requires_python = get_requires_python(dist)
+    try:
+        is_compatible = check_requires_python(
+            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,
+        )
+        return
+
+    if is_compatible:
+        return
+
+    version = '.'.join(map(str, version_info))
+    if ignore_requires_python:
+        logger.debug(
+            'Ignoring failed Requires-Python check for package %r: '
+            '%s not in %r',
+            dist.project_name, version, requires_python,
+        )
+        return
+
+    raise UnsupportedPythonVersion(
+        'Package {!r} requires a different Python: {} not in {!r}'.format(
+            dist.project_name, version, requires_python,
+        ))
+
+
+class Resolver(object):
+    """Resolves which packages need to be installed/uninstalled to perform \
+    the requested operation without breaking the requirements of any package.
+    """
+
+    _allowed_strategies = {"eager", "only-if-needed", "to-satisfy-only"}
+
+    def __init__(
+        self,
+        preparer,  # type: RequirementPreparer
+        finder,  # type: PackageFinder
+        make_install_req,  # type: InstallRequirementProvider
+        use_user_site,  # type: bool
+        ignore_dependencies,  # type: bool
+        ignore_installed,  # type: bool
+        ignore_requires_python,  # type: bool
+        force_reinstall,  # type: bool
+        upgrade_strategy,  # type: str
+        py_version_info=None,  # type: Optional[Tuple[int, ...]]
+    ):
+        # type: (...) -> None
+        super(Resolver, self).__init__()
+        assert upgrade_strategy in self._allowed_strategies
+
+        if py_version_info is None:
+            py_version_info = sys.version_info[:3]
+        else:
+            py_version_info = normalize_version_info(py_version_info)
+
+        self._py_version_info = py_version_info
+
+        self.preparer = preparer
+        self.finder = finder
+
+        self.upgrade_strategy = upgrade_strategy
+        self.force_reinstall = force_reinstall
+        self.ignore_dependencies = ignore_dependencies
+        self.ignore_installed = ignore_installed
+        self.ignore_requires_python = ignore_requires_python
+        self.use_user_site = use_user_site
+        self._make_install_req = make_install_req
+
+        self._discovered_dependencies = \
+            defaultdict(list)  # type: DiscoveredDependencies
+
+    def resolve(self, requirement_set):
+        # type: (RequirementSet) -> None
+        """Resolve what operations need to be done
+
+        As a side-effect of this method, the packages (and their dependencies)
+        are downloaded, unpacked and prepared for installation. This
+        preparation is done by ``pip.operations.prepare``.
+
+        Once PyPI has static dependency metadata available, it would be
+        possible to move the preparation to become a step separated from
+        dependency resolution.
+        """
+        # If any top-level requirement has a hash specified, enter
+        # hash-checking mode, which requires hashes from all.
+        root_reqs = (
+            requirement_set.unnamed_requirements +
+            list(requirement_set.requirements.values())
+        )
+
+        # Actually prepare the files, and collect any exceptions. Most hash
+        # exceptions cannot be checked ahead of time, because
+        # req.populate_link() needs to be called before we can make decisions
+        # based on link type.
+        discovered_reqs = []  # type: List[InstallRequirement]
+        hash_errors = HashErrors()
+        for req in chain(root_reqs, discovered_reqs):
+            try:
+                discovered_reqs.extend(self._resolve_one(requirement_set, req))
+            except HashError as exc:
+                exc.req = req
+                hash_errors.append(exc)
+
+        if hash_errors:
+            raise hash_errors
+
+    def _is_upgrade_allowed(self, req):
+        # type: (InstallRequirement) -> bool
+        if self.upgrade_strategy == "to-satisfy-only":
+            return False
+        elif self.upgrade_strategy == "eager":
+            return True
+        else:
+            assert self.upgrade_strategy == "only-if-needed"
+            return req.is_direct
+
+    def _set_req_to_reinstall(self, req):
+        # type: (InstallRequirement) -> None
+        """
+        Set a requirement to be installed.
+        """
+        # 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):
+            req.should_reinstall = True
+        req.satisfied_by = None
+
+    def _check_skip_installed(self, req_to_install):
+        # type: (InstallRequirement) -> Optional[str]
+        """Check if req_to_install should be skipped.
+
+        This will check if the req is installed, and whether we should upgrade
+        or reinstall it, taking into account all the relevant user options.
+
+        After calling this req_to_install will only have satisfied_by set to
+        None if the req_to_install is to be upgraded/reinstalled etc. Any
+        other value will be a dist recording the current thing installed that
+        satisfies the requirement.
+
+        Note that for vcs urls and the like we can't assess skipping in this
+        routine - we simply identify that we need to pull the thing down,
+        then later on it is pulled down and introspected to assess upgrade/
+        reinstalls etc.
+
+        :return: A text reason for why it was skipped, or None.
+        """
+        if self.ignore_installed:
+            return None
+
+        req_to_install.check_if_exists(self.use_user_site)
+        if not req_to_install.satisfied_by:
+            return None
+
+        if self.force_reinstall:
+            self._set_req_to_reinstall(req_to_install)
+            return None
+
+        if not self._is_upgrade_allowed(req_to_install):
+            if self.upgrade_strategy == "only-if-needed":
+                return 'already satisfied, skipping upgrade'
+            return 'already satisfied'
+
+        # Check for the possibility of an upgrade.  For link-based
+        # requirements we have to pull the tree down and inspect to assess
+        # the version #, so it's handled way down.
+        if not req_to_install.link:
+            try:
+                self.finder.find_requirement(req_to_install, upgrade=True)
+            except BestVersionAlreadyInstalled:
+                # Then the best version is installed.
+                return 'already up-to-date'
+            except DistributionNotFound:
+                # No distribution found, so we squash the error.  It will
+                # be raised later when we re-try later to do the install.
+                # Why don't we just raise here?
+                pass
+
+        self._set_req_to_reinstall(req_to_install)
+        return None
+
+    def _get_abstract_dist_for(self, req):
+        # type: (InstallRequirement) -> AbstractDistribution
+        """Takes a InstallRequirement and returns a single AbstractDist \
+        representing a prepared variant of the same.
+        """
+        if req.editable:
+            return self.preparer.prepare_editable_requirement(req)
+
+        # satisfied_by is only evaluated by calling _check_skip_installed,
+        # so it must be None here.
+        assert req.satisfied_by is None
+        skip_reason = self._check_skip_installed(req)
+
+        if req.satisfied_by:
+            return self.preparer.prepare_installed_requirement(
+                req, skip_reason
+            )
+
+        upgrade_allowed = self._is_upgrade_allowed(req)
+
+        # We eagerly populate the link, since that's our "legacy" behavior.
+        require_hashes = self.preparer.require_hashes
+        req.populate_link(self.finder, upgrade_allowed, require_hashes)
+        abstract_dist = self.preparer.prepare_linked_requirement(req)
+
+        # NOTE
+        # The following portion is for determining if a certain package is
+        # going to be re-installed/upgraded or not and reporting to the user.
+        # This should probably get cleaned up in a future refactor.
+
+        # req.req is only avail after unpack for URL
+        # pkgs repeat check_if_exists to uninstall-on-upgrade
+        # (#14)
+        if not self.ignore_installed:
+            req.check_if_exists(self.use_user_site)
+
+        if req.satisfied_by:
+            should_modify = (
+                self.upgrade_strategy != "to-satisfy-only" or
+                self.force_reinstall or
+                self.ignore_installed or
+                req.link.scheme == 'file'
+            )
+            if should_modify:
+                self._set_req_to_reinstall(req)
+            else:
+                logger.info(
+                    'Requirement already satisfied (use --upgrade to upgrade):'
+                    ' %s', req,
+                )
+
+        return abstract_dist
+
+    def _resolve_one(
+        self,
+        requirement_set,  # type: RequirementSet
+        req_to_install,  # type: InstallRequirement
+    ):
+        # type: (...) -> List[InstallRequirement]
+        """Prepare a single requirements file.
+
+        :return: A list of additional InstallRequirements to also install.
+        """
+        # Tell user what we are doing for this requirement:
+        # obtain (editable), skipping, processing (local url), collecting
+        # (remote url or package name)
+        if req_to_install.constraint or req_to_install.prepared:
+            return []
+
+        req_to_install.prepared = True
+
+        # register tmp src for cleanup in case something goes wrong
+        requirement_set.reqs_to_cleanup.append(req_to_install)
+
+        abstract_dist = self._get_abstract_dist_for(req_to_install)
+
+        # Parse and return dependencies
+        dist = abstract_dist.get_pkg_resources_distribution()
+        # This will raise UnsupportedPythonVersion if the given Python
+        # version isn't compatible with the distribution's Requires-Python.
+        _check_dist_requires_python(
+            dist, version_info=self._py_version_info,
+            ignore_requires_python=self.ignore_requires_python,
+        )
+
+        more_reqs = []  # type: List[InstallRequirement]
+
+        def add_req(subreq, extras_requested):
+            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(
+                sub_install_req,
+                parent_req_name=parent_req_name,
+                extras_requested=extras_requested,
+            )
+            if parent_req_name and add_to_parent:
+                self._discovered_dependencies[parent_req_name].append(
+                    add_to_parent
+                )
+            more_reqs.extend(to_scan_again)
+
+        with indent_log():
+            # We add req_to_install before its dependencies, so that we
+            # can refer to it when adding dependencies.
+            if not requirement_set.has_requirement(req_to_install.name):
+                # 'unnamed' requirements will get added here
+                # 'unnamed' requirements can only come from being directly
+                # provided by the user.
+                assert req_to_install.is_direct
+                requirement_set.add_requirement(
+                    req_to_install, parent_req_name=None,
+                )
+
+            if not self.ignore_dependencies:
+                if req_to_install.extras:
+                    logger.debug(
+                        "Installing extra requirements: %r",
+                        ','.join(req_to_install.extras),
+                    )
+                missing_requested = sorted(
+                    set(req_to_install.extras) - set(dist.extras)
+                )
+                for missing in missing_requested:
+                    logger.warning(
+                        '%s does not provide the extra \'%s\'',
+                        dist, missing
+                    )
+
+                available_requested = sorted(
+                    set(dist.extras) & set(req_to_install.extras)
+                )
+                for subreq in dist.requires(available_requested):
+                    add_req(subreq, extras_requested=available_requested)
+
+            if not req_to_install.editable and not req_to_install.satisfied_by:
+                # XXX: --no-install leads this to report 'Successfully
+                # downloaded' for only non-editable reqs, even though we took
+                # action on them.
+                requirement_set.successfully_downloaded.append(req_to_install)
+
+        return more_reqs
+
+    def get_installation_order(self, req_set):
+        # type: (RequirementSet) -> List[InstallRequirement]
+        """Create the installation order.
+
+        The installation order is topological - requirements are installed
+        before the requiring thing. We break cycles at an arbitrary point,
+        and make no other guarantees.
+        """
+        # The current implementation, which we may change at any point
+        # installs the user specified things in the order given, except when
+        # dependencies must come earlier to achieve topological order.
+        order = []
+        ordered_reqs = set()  # type: Set[InstallRequirement]
+
+        def schedule(req):
+            if req.satisfied_by or req in ordered_reqs:
+                return
+            if req.constraint:
+                return
+            ordered_reqs.add(req)
+            for dep in self._discovered_dependencies[req.name]:
+                schedule(dep)
+            order.append(req)
+
+        for install_req in req_set.requirements.values():
+            schedule(install_req)
+        return order

venv/lib/python3.8/site-packages/pip/_internal/locations.py

@@ -0,0 +1,194 @@
+"""Locations where we look for configs, install stuff, etc"""
+
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+
+from __future__ import absolute_import
+
+import os
+import os.path
+import platform
+import site
+import sys
+import sysconfig
+from distutils import sysconfig as distutils_sysconfig
+from distutils.command.install import SCHEME_KEYS  # type: ignore
+from distutils.command.install import install as distutils_install_command
+
+from pip._internal.models.scheme import Scheme
+from pip._internal.utils import appdirs
+from pip._internal.utils.compat import WINDOWS
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING, cast
+from pip._internal.utils.virtualenv import running_under_virtualenv
+
+if MYPY_CHECK_RUNNING:
+    from typing import Dict, List, Optional, Union
+
+    from distutils.cmd import Command as DistutilsCommand
+
+
+# Application Directories
+USER_CACHE_DIR = appdirs.user_cache_dir("pip")
+
+
+def get_major_minor_version():
+    # type: () -> str
+    """
+    Return the major-minor version of the current Python as a string, e.g.
+    "3.7" or "3.10".
+    """
+    return '{}.{}'.format(*sys.version_info)
+
+
+def get_src_prefix():
+    # type: () -> str
+    if running_under_virtualenv():
+        src_prefix = os.path.join(sys.prefix, 'src')
+    else:
+        # FIXME: keep src in cwd for now (it is not a temporary folder)
+        try:
+            src_prefix = os.path.join(os.getcwd(), 'src')
+        except OSError:
+            # In case the current working directory has been renamed or deleted
+            sys.exit(
+                "The folder you are executing pip from can no longer be found."
+            )
+
+    # under macOS + virtualenv sys.prefix is not properly resolved
+    # it is something like /path/to/python/bin/..
+    return os.path.abspath(src_prefix)
+
+
+# FIXME doesn't account for venv linked to global site-packages
+
+site_packages = sysconfig.get_path("purelib")  # type: Optional[str]
+
+# This is because of a bug in PyPy's sysconfig module, see
+# https://bitbucket.org/pypy/pypy/issues/2506/sysconfig-returns-incorrect-paths
+# for more information.
+if platform.python_implementation().lower() == "pypy":
+    site_packages = distutils_sysconfig.get_python_lib()
+try:
+    # Use getusersitepackages if this is present, as it ensures that the
+    # value is initialised properly.
+    user_site = site.getusersitepackages()
+except AttributeError:
+    user_site = site.USER_SITE
+
+if WINDOWS:
+    bin_py = os.path.join(sys.prefix, 'Scripts')
+    bin_user = os.path.join(user_site, 'Scripts')
+    # buildout uses 'bin' on Windows too?
+    if not os.path.exists(bin_py):
+        bin_py = os.path.join(sys.prefix, 'bin')
+        bin_user = os.path.join(user_site, 'bin')
+else:
+    bin_py = os.path.join(sys.prefix, 'bin')
+    bin_user = os.path.join(user_site, 'bin')
+
+    # Forcing to use /usr/local/bin for standard macOS framework installs
+    # Also log to ~/Library/Logs/ for use with the Console.app log viewer
+    if sys.platform[:6] == 'darwin' and sys.prefix[:16] == '/System/Library/':
+        bin_py = '/usr/local/bin'
+
+
+def distutils_scheme(
+    dist_name, user=False, home=None, root=None, isolated=False, prefix=None
+):
+    # type:(str, bool, str, str, bool, str) -> Dict[str, str]
+    """
+    Return a distutils install scheme
+    """
+    from distutils.dist import Distribution
+
+    dist_args = {'name': dist_name}  # type: Dict[str, Union[str, List[str]]]
+    if isolated:
+        dist_args["script_args"] = ["--no-user-cfg"]
+
+    d = Distribution(dist_args)
+    d.parse_config_files()
+    obj = None  # type: Optional[DistutilsCommand]
+    obj = d.get_command_obj('install', create=True)
+    assert obj is not None
+    i = cast(distutils_install_command, obj)
+    # NOTE: setting user or home has the side-effect of creating the home dir
+    # or user base for installations during finalize_options()
+    # ideally, we'd prefer a scheme class that has no side-effects.
+    assert not (user and prefix), "user={} prefix={}".format(user, prefix)
+    assert not (home and prefix), "home={} prefix={}".format(home, prefix)
+    i.user = user or i.user
+    if user or home:
+        i.prefix = ""
+    i.prefix = prefix or i.prefix
+    i.home = home or i.home
+    i.root = root or i.root
+    i.finalize_options()
+
+    scheme = {}
+    for key in SCHEME_KEYS:
+        scheme[key] = getattr(i, 'install_' + key)
+
+    # install_lib specified in setup.cfg should install *everything*
+    # into there (i.e. it takes precedence over both purelib and
+    # platlib).  Note, i.install_lib is *always* set after
+    # finalize_options(); we only want to override here if the user
+    # has explicitly requested it hence going back to the config
+    if 'install_lib' in d.get_option_dict('install'):
+        scheme.update(dict(purelib=i.install_lib, platlib=i.install_lib))
+
+    if running_under_virtualenv():
+        scheme['headers'] = os.path.join(
+            sys.prefix,
+            'include',
+            'site',
+            'python{}'.format(get_major_minor_version()),
+            dist_name,
+        )
+
+        if root is not None:
+            path_no_drive = os.path.splitdrive(
+                os.path.abspath(scheme["headers"]))[1]
+            scheme["headers"] = os.path.join(
+                root,
+                path_no_drive[1:],
+            )
+
+    return scheme
+
+
+def get_scheme(
+    dist_name,  # type: str
+    user=False,  # type: bool
+    home=None,  # type: Optional[str]
+    root=None,  # type: Optional[str]
+    isolated=False,  # type: bool
+    prefix=None,  # type: Optional[str]
+):
+    # type: (...) -> Scheme
+    """
+    Get the "scheme" corresponding to the input parameters. The distutils
+    documentation provides the context for the available schemes:
+    https://docs.python.org/3/install/index.html#alternate-installation
+
+    :param dist_name: the name of the package to retrieve the scheme for, used
+        in the headers scheme path
+    :param user: indicates to use the "user" scheme
+    :param home: indicates to use the "home" scheme and provides the base
+        directory for the same
+    :param root: root under which other directories are re-based
+    :param isolated: equivalent to --no-user-cfg, i.e. do not consider
+        ~/.pydistutils.cfg (posix) or ~/pydistutils.cfg (non-posix) for
+        scheme paths
+    :param prefix: indicates to use the "prefix" scheme and provides the
+        base directory for the same
+    """
+    scheme = distutils_scheme(
+        dist_name, user, home, root, isolated, prefix
+    )
+    return Scheme(
+        platlib=scheme["platlib"],
+        purelib=scheme["purelib"],
+        headers=scheme["headers"],
+        scripts=scheme["scripts"],
+        data=scheme["data"],
+    )

venv/lib/python3.8/site-packages/pip/_internal/main.py

@@ -0,0 +1,16 @@
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Optional, List
+
+
+def main(args=None):
+    # type: (Optional[List[str]]) -> int
+    """This is preserved for old console scripts that may still be referencing
+    it.
+
+    For additional details, see https://github.com/pypa/pip/issues/7498.
+    """
+    from pip._internal.utils.entrypoints import _wrapper
+
+    return _wrapper(args)

venv/lib/python3.8/site-packages/pip/_internal/models/__init__.py

@@ -0,0 +1,2 @@
+"""A package that contains models that represent entities.
+"""

venv/lib/python3.8/site-packages/pip/_internal/models/candidate.py

@@ -0,0 +1,36 @@
+from pip._vendor.packaging.version import parse as parse_version
+
+from pip._internal.utils.models import KeyBasedCompareMixin
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from pip._vendor.packaging.version import _BaseVersion
+    from pip._internal.models.link import Link
+
+
+class InstallationCandidate(KeyBasedCompareMixin):
+    """Represents a potential "candidate" for installation.
+    """
+
+    def __init__(self, name, version, link):
+        # type: (str, str, Link) -> None
+        self.name = name
+        self.version = parse_version(version)  # type: _BaseVersion
+        self.link = link
+
+        super(InstallationCandidate, self).__init__(
+            key=(self.name, self.version, self.link),
+            defining_class=InstallationCandidate
+        )
+
+    def __repr__(self):
+        # type: () -> str
+        return "<InstallationCandidate({!r}, {!r}, {!r})>".format(
+            self.name, self.version, self.link,
+        )
+
+    def __str__(self):
+        # type: () -> str
+        return '{!r} candidate (version {} at {})'.format(
+            self.name, self.version, self.link,
+        )

venv/lib/python3.8/site-packages/pip/_internal/models/format_control.py

@@ -0,0 +1,84 @@
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+
+from pip._vendor.packaging.utils import canonicalize_name
+
+from pip._internal.exceptions import CommandError
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Optional, Set, FrozenSet
+
+
+class FormatControl(object):
+    """Helper for managing formats from which a package can be installed.
+    """
+
+    def __init__(self, no_binary=None, only_binary=None):
+        # type: (Optional[Set[str]], Optional[Set[str]]) -> None
+        if no_binary is None:
+            no_binary = set()
+        if only_binary is None:
+            only_binary = set()
+
+        self.no_binary = no_binary
+        self.only_binary = only_binary
+
+    def __eq__(self, other):
+        # type: (object) -> bool
+        return self.__dict__ == other.__dict__
+
+    def __ne__(self, other):
+        # type: (object) -> bool
+        return not self.__eq__(other)
+
+    def __repr__(self):
+        # type: () -> str
+        return "{}({}, {})".format(
+            self.__class__.__name__,
+            self.no_binary,
+            self.only_binary
+        )
+
+    @staticmethod
+    def handle_mutual_excludes(value, target, other):
+        # type: (str, Optional[Set[str]], Optional[Set[str]]) -> None
+        if value.startswith('-'):
+            raise CommandError(
+                "--no-binary / --only-binary option requires 1 argument."
+            )
+        new = value.split(',')
+        while ':all:' in new:
+            other.clear()
+            target.clear()
+            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:
+                return
+        for name in new:
+            if name == ':none:':
+                target.clear()
+                continue
+            name = canonicalize_name(name)
+            other.discard(name)
+            target.add(name)
+
+    def get_allowed_formats(self, canonical_name):
+        # type: (str) -> FrozenSet[str]
+        result = {"binary", "source"}
+        if canonical_name in self.only_binary:
+            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')
+        return frozenset(result)
+
+    def disallow_binaries(self):
+        # type: () -> None
+        self.handle_mutual_excludes(
+            ':all:', self.no_binary, self.only_binary,
+        )

venv/lib/python3.8/site-packages/pip/_internal/models/index.py

@@ -0,0 +1,31 @@
+from pip._vendor.six.moves.urllib import parse as urllib_parse
+
+
+class PackageIndex(object):
+    """Represents a Package Index and provides easier access to endpoints
+    """
+
+    def __init__(self, url, file_storage_domain):
+        # type: (str, str) -> None
+        super(PackageIndex, self).__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')
+
+        # This is part of a temporary hack used to block installs of PyPI
+        # packages which depend on external urls only necessary until PyPI can
+        # block such packages themselves
+        self.file_storage_domain = file_storage_domain
+
+    def _url_for_path(self, path):
+        # type: (str) -> str
+        return urllib_parse.urljoin(self.url, path)
+
+
+PyPI = PackageIndex(
+    'https://pypi.org/', file_storage_domain='files.pythonhosted.org'
+)
+TestPyPI = PackageIndex(
+    'https://test.pypi.org/', file_storage_domain='test-files.pythonhosted.org'
+)

venv/lib/python3.8/site-packages/pip/_internal/models/link.py

@@ -0,0 +1,227 @@
+import os
+import posixpath
+import re
+
+from pip._vendor.six.moves.urllib import parse as urllib_parse
+
+from pip._internal.utils.filetypes import WHEEL_EXTENSION
+from pip._internal.utils.misc import (
+    redact_auth_from_url,
+    split_auth_from_netloc,
+    splitext,
+)
+from pip._internal.utils.models import KeyBasedCompareMixin
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.urls import path_to_url, url_to_path
+
+if MYPY_CHECK_RUNNING:
+    from typing import Optional, Text, Tuple, Union
+    from pip._internal.index.collector import HTMLPage
+    from pip._internal.utils.hashes import Hashes
+
+
+class Link(KeyBasedCompareMixin):
+    """Represents a parsed link from a Package Index's simple URL
+    """
+
+    def __init__(
+        self,
+        url,                   # type: str
+        comes_from=None,       # type: Optional[Union[str, HTMLPage]]
+        requires_python=None,  # type: Optional[str]
+        yanked_reason=None,    # type: Optional[Text]
+    ):
+        # type: (...) -> None
+        """
+        :param url: url of the resource pointed to (href of the link)
+        :param comes_from: instance of HTMLPage 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
+            a data-requires-python attribute in the HTML link tag, as
+            described in PEP 503.
+        :param yanked_reason: the reason the file has been yanked, if the
+            file has been yanked, or None if the file hasn't been yanked.
+            This is the value of the "data-yanked" attribute, if present, in
+            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.
+        """
+
+        # url can be a UNC windows share
+        if url.startswith('\\\\'):
+            url = path_to_url(url)
+
+        self._parsed_url = urllib_parse.urlsplit(url)
+        # Store the url as a private attribute to prevent accidentally
+        # trying to set a new value.
+        self._url = url
+
+        self.comes_from = comes_from
+        self.requires_python = requires_python if requires_python else None
+        self.yanked_reason = yanked_reason
+
+        super(Link, self).__init__(key=url, defining_class=Link)
+
+    def __str__(self):
+        # type: () -> str
+        if self.requires_python:
+            rp = ' (requires-python:%s)' % self.requires_python
+        else:
+            rp = ''
+        if self.comes_from:
+            return '%s (from %s)%s' % (redact_auth_from_url(self._url),
+                                       self.comes_from, rp)
+        else:
+            return redact_auth_from_url(str(self._url))
+
+    def __repr__(self):
+        # type: () -> str
+        return '<Link %s>' % self
+
+    @property
+    def url(self):
+        # type: () -> str
+        return self._url
+
+    @property
+    def filename(self):
+        # type: () -> str
+        path = self.path.rstrip('/')
+        name = posixpath.basename(path)
+        if not name:
+            # Make sure we don't leak auth information if the netloc
+            # includes a username and password.
+            netloc, user_pass = split_auth_from_netloc(self.netloc)
+            return netloc
+
+        name = urllib_parse.unquote(name)
+        assert name, ('URL %r produced no filename' % self._url)
+        return name
+
+    @property
+    def file_path(self):
+        # type: () -> str
+        return url_to_path(self.url)
+
+    @property
+    def scheme(self):
+        # type: () -> str
+        return self._parsed_url.scheme
+
+    @property
+    def netloc(self):
+        # type: () -> str
+        """
+        This can contain auth information.
+        """
+        return self._parsed_url.netloc
+
+    @property
+    def path(self):
+        # type: () -> str
+        return urllib_parse.unquote(self._parsed_url.path)
+
+    def splitext(self):
+        # type: () -> Tuple[str, str]
+        return splitext(posixpath.basename(self.path.rstrip('/')))
+
+    @property
+    def ext(self):
+        # type: () -> str
+        return self.splitext()[1]
+
+    @property
+    def url_without_fragment(self):
+        # type: () -> str
+        scheme, netloc, path, query, fragment = self._parsed_url
+        return urllib_parse.urlunsplit((scheme, netloc, path, query, None))
+
+    _egg_fragment_re = re.compile(r'[#&]egg=([^&]*)')
+
+    @property
+    def egg_fragment(self):
+        # type: () -> 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=([^&]*)')
+
+    @property
+    def subdirectory_fragment(self):
+        # type: () -> Optional[str]
+        match = self._subdirectory_fragment_re.search(self._url)
+        if not match:
+            return None
+        return match.group(1)
+
+    _hash_re = re.compile(
+        r'(sha1|sha224|sha384|sha256|sha512|md5)=([a-f0-9]+)'
+    )
+
+    @property
+    def hash(self):
+        # type: () -> Optional[str]
+        match = self._hash_re.search(self._url)
+        if match:
+            return match.group(2)
+        return None
+
+    @property
+    def hash_name(self):
+        # type: () -> Optional[str]
+        match = self._hash_re.search(self._url)
+        if match:
+            return match.group(1)
+        return None
+
+    @property
+    def show_url(self):
+        # type: () -> str
+        return posixpath.basename(self._url.split('#', 1)[0].split('?', 1)[0])
+
+    @property
+    def is_file(self):
+        # type: () -> bool
+        return self.scheme == 'file'
+
+    def is_existing_dir(self):
+        # type: () -> bool
+        return self.is_file and os.path.isdir(self.file_path)
+
+    @property
+    def is_wheel(self):
+        # type: () -> bool
+        return self.ext == WHEEL_EXTENSION
+
+    @property
+    def is_vcs(self):
+        # type: () -> bool
+        from pip._internal.vcs import vcs
+
+        return self.scheme in vcs.all_schemes
+
+    @property
+    def is_yanked(self):
+        # type: () -> bool
+        return self.yanked_reason is not None
+
+    @property
+    def has_hash(self):
+        # type: () -> bool
+        return self.hash_name is not None
+
+    def is_hash_allowed(self, hashes):
+        # type: (Optional[Hashes]) -> bool
+        """
+        Return True if the link has a hash and it is allowed.
+        """
+        if hashes is None or not self.has_hash:
+            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)

venv/lib/python3.8/site-packages/pip/_internal/models/scheme.py

@@ -0,0 +1,25 @@
+"""
+For types associated with installation schemes.
+
+For a general overview of available schemes and their context, see
+https://docs.python.org/3/install/index.html#alternate-installation.
+"""
+
+
+class Scheme(object):
+    """A Scheme holds paths which are used as the base directories for
+    artifacts associated with a Python package.
+    """
+    def __init__(
+        self,
+        platlib,  # type: str
+        purelib,  # type: str
+        headers,  # type: str
+        scripts,  # type: str
+        data,  # type: str
+    ):
+        self.platlib = platlib
+        self.purelib = purelib
+        self.headers = headers
+        self.scripts = scripts
+        self.data = data

venv/lib/python3.8/site-packages/pip/_internal/models/search_scope.py

@@ -0,0 +1,114 @@
+import itertools
+import logging
+import os
+import posixpath
+
+from pip._vendor.packaging.utils import canonicalize_name
+from pip._vendor.six.moves.urllib import parse as urllib_parse
+
+from pip._internal.models.index import PyPI
+from pip._internal.utils.compat import has_tls
+from pip._internal.utils.misc import normalize_path, redact_auth_from_url
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import List
+
+
+logger = logging.getLogger(__name__)
+
+
+class SearchScope(object):
+
+    """
+    Encapsulates the locations that pip is configured to search.
+    """
+
+    @classmethod
+    def create(
+        cls,
+        find_links,  # type: List[str]
+        index_urls,  # type: List[str]
+    ):
+        # type: (...) -> SearchScope
+        """
+        Create a SearchScope object after normalizing the `find_links`.
+        """
+        # Build find_links. If an argument starts with ~, it may be
+        # a local file relative to a home directory. So try normalizing
+        # it and if it exists, use the normalized version.
+        # This is deliberately conservative - it might be fine just to
+        # blindly normalize anything starting with a ~...
+        built_find_links = []  # type: List[str]
+        for link in find_links:
+            if link.startswith('~'):
+                new_link = normalize_path(link)
+                if os.path.exists(new_link):
+                    link = new_link
+            built_find_links.append(link)
+
+        # If we don't have TLS enabled, then WARN if anyplace we're looking
+        # relies on TLS.
+        if not has_tls():
+            for link in itertools.chain(index_urls, built_find_links):
+                parsed = urllib_parse.urlparse(link)
+                if parsed.scheme == 'https':
+                    logger.warning(
+                        '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,
+        )
+
+    def __init__(
+        self,
+        find_links,  # type: List[str]
+        index_urls,  # type: List[str]
+    ):
+        # type: (...) -> None
+        self.find_links = find_links
+        self.index_urls = index_urls
+
+    def get_formatted_locations(self):
+        # type: () -> str
+        lines = []
+        if self.index_urls and self.index_urls != [PyPI.simple_url]:
+            lines.append(
+                'Looking in indexes: {}'.format(', '.join(
+                    redact_auth_from_url(url) for url in self.index_urls))
+            )
+        if self.find_links:
+            lines.append(
+                'Looking in links: {}'.format(', '.join(
+                    redact_auth_from_url(url) for url in self.find_links))
+            )
+        return '\n'.join(lines)
+
+    def get_index_urls_locations(self, project_name):
+        # type: (str) -> List[str]
+        """Returns the locations found via self.index_urls
+
+        Checks the url_name on the main (first in the list) index and
+        use this url_name to produce all locations
+        """
+
+        def mkurl_pypi_url(url):
+            # type: (str) -> str
+            loc = posixpath.join(
+                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 + '/'
+            return loc
+
+        return [mkurl_pypi_url(url) for url in self.index_urls]

venv/lib/python3.8/site-packages/pip/_internal/models/selection_prefs.py

@@ -0,0 +1,47 @@
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Optional
+    from pip._internal.models.format_control import FormatControl
+
+
+class SelectionPreferences(object):
+
+    """
+    Encapsulates the candidate selection preferences for downloading
+    and installing files.
+    """
+
+    # Don't include an allow_yanked default value to make sure each call
+    # site considers whether yanked releases are allowed. This also causes
+    # that decision to be made explicit in the calling code, which helps
+    # people when reading the code.
+    def __init__(
+        self,
+        allow_yanked,  # type: bool
+        allow_all_prereleases=False,  # type: bool
+        format_control=None,          # type: Optional[FormatControl]
+        prefer_binary=False,          # type: bool
+        ignore_requires_python=None,  # type: Optional[bool]
+    ):
+        # type: (...) -> None
+        """Create a SelectionPreferences object.
+
+        :param allow_yanked: Whether files marked as yanked (in the sense
+            of PEP 592) are permitted to be candidates for install.
+        :param format_control: A FormatControl object or None. Used to control
+            the selection of source packages / binary packages when consulting
+            the index and links.
+        :param prefer_binary: Whether to prefer an old, but valid, binary
+            dist over a new source dist.
+        :param ignore_requires_python: Whether to ignore incompatible
+            "Requires-Python" values in links. Defaults to False.
+        """
+        if ignore_requires_python is None:
+            ignore_requires_python = False
+
+        self.allow_yanked = allow_yanked
+        self.allow_all_prereleases = allow_all_prereleases
+        self.format_control = format_control
+        self.prefer_binary = prefer_binary
+        self.ignore_requires_python = ignore_requires_python

venv/lib/python3.8/site-packages/pip/_internal/models/target_python.py

@@ -0,0 +1,107 @@
+import sys
+
+from pip._internal.pep425tags import get_supported, version_info_to_nodot
+from pip._internal.utils.misc import normalize_version_info
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import List, Optional, Tuple
+
+    from pip._vendor.packaging.tags import Tag
+
+
+class TargetPython(object):
+
+    """
+    Encapsulates the properties of a Python interpreter one is targeting
+    for a package install, download, etc.
+    """
+
+    def __init__(
+        self,
+        platform=None,  # type: Optional[str]
+        py_version_info=None,  # type: Optional[Tuple[int, ...]]
+        abi=None,  # type: Optional[str]
+        implementation=None,  # type: Optional[str]
+    ):
+        # type: (...) -> None
+        """
+        :param platform: A string or None. If None, searches for packages
+            that are supported by the current system. Otherwise, will find
+            packages that can be built on the platform passed in. These
+            packages will only be downloaded for distribution: they will
+            not be built locally.
+        :param py_version_info: An optional tuple of ints representing the
+            Python version information to use (e.g. `sys.version_info[:3]`).
+            This can have length 1, 2, or 3 when provided.
+        :param abi: A string or None. This is passed to pep425tags.py's
+            get_supported() function as is.
+        :param implementation: A string or None. This is passed to
+            pep425tags.py's get_supported() function as is.
+        """
+        # Store the given py_version_info for when we call get_supported().
+        self._given_py_version_info = py_version_info
+
+        if py_version_info is None:
+            py_version_info = sys.version_info[:3]
+        else:
+            py_version_info = normalize_version_info(py_version_info)
+
+        py_version = '.'.join(map(str, py_version_info[:2]))
+
+        self.abi = abi
+        self.implementation = implementation
+        self.platform = platform
+        self.py_version = py_version
+        self.py_version_info = py_version_info
+
+        # This is used to cache the return value of get_tags().
+        self._valid_tags = None  # type: Optional[List[Tag]]
+
+    def format_given(self):
+        # type: () -> str
+        """
+        Format the given, non-None attributes for display.
+        """
+        display_version = None
+        if self._given_py_version_info is not None:
+            display_version = '.'.join(
+                str(part) for part in self._given_py_version_info
+            )
+
+        key_values = [
+            ('platform', self.platform),
+            ('version_info', display_version),
+            ('abi', self.abi),
+            ('implementation', self.implementation),
+        ]
+        return ' '.join(
+            '{}={!r}'.format(key, value) for key, value in key_values
+            if value is not None
+        )
+
+    def get_tags(self):
+        # type: () -> List[Tag]
+        """
+        Return the supported PEP 425 tags to check wheel candidates against.
+
+        The tags are returned in order of preference (most preferred first).
+        """
+        if self._valid_tags is None:
+            # Pass versions=None if no py_version_info was given since
+            # versions=None uses special default logic.
+            py_version_info = self._given_py_version_info
+            if py_version_info is None:
+                version = None
+            else:
+                version = version_info_to_nodot(py_version_info)
+
+            tags = get_supported(
+                version=version,
+                platform=self.platform,
+                abi=self.abi,
+                impl=self.implementation,
+            )
+            self._valid_tags = tags
+
+        return self._valid_tags

venv/lib/python3.8/site-packages/pip/_internal/models/wheel.py

@@ -0,0 +1,78 @@
+"""Represents a wheel file and provides access to the various parts of the
+name that have meaning.
+"""
+import re
+
+from pip._vendor.packaging.tags import Tag
+
+from pip._internal.exceptions import InvalidWheelFilename
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import List
+
+
+class Wheel(object):
+    """A wheel file"""
+
+    wheel_file_re = re.compile(
+        r"""^(?P<namever>(?P<name>.+?)-(?P<ver>.*?))
+        ((-(?P<build>\d[^-]*?))?-(?P<pyver>.+?)-(?P<abi>.+?)-(?P<plat>.+?)
+        \.whl|\.dist-info)$""",
+        re.VERBOSE
+    )
+
+    def __init__(self, filename):
+        # type: (str) -> None
+        """
+        :raises InvalidWheelFilename: when the filename is invalid for a wheel
+        """
+        wheel_info = self.wheel_file_re.match(filename)
+        if not wheel_info:
+            raise InvalidWheelFilename(
+                "%s is not a valid wheel filename." % filename
+            )
+        self.filename = filename
+        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('.')
+
+        # 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
+        }
+
+    def get_formatted_file_tags(self):
+        # type: () -> List[str]
+        """Return the wheel's tags as a sorted list of strings."""
+        return sorted(str(tag) for tag in self.file_tags)
+
+    def support_index_min(self, tags):
+        # type: (List[Tag]) -> int
+        """Return the lowest index that one of the wheel's file_tag combinations
+        achieves in the given list of supported tags.
+
+        For example, if there are 8 supported tags and one of the file tags
+        is first in the list, then return 0.
+
+        :param tags: the PEP 425 tags to check the wheel against, in order
+            with most preferred first.
+
+        :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)
+
+    def supported(self, tags):
+        # type: (List[Tag]) -> bool
+        """Return whether the wheel is compatible with one of the given tags.
+
+        :param tags: the PEP 425 tags to check the wheel against.
+        """
+        return not self.file_tags.isdisjoint(tags)

venv/lib/python3.8/site-packages/pip/_internal/network/__init__.py

@@ -0,0 +1,2 @@
+"""Contains purely network-related utilities.
+"""

venv/lib/python3.8/site-packages/pip/_internal/network/auth.py

@@ -0,0 +1,298 @@
+"""Network Authentication Helpers
+
+Contains interface (MultiDomainBasicAuth) and associated glue code for
+providing credentials in the context of network requests.
+"""
+
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+import logging
+
+from pip._vendor.requests.auth import AuthBase, HTTPBasicAuth
+from pip._vendor.requests.utils import get_netrc_auth
+from pip._vendor.six.moves.urllib import parse as urllib_parse
+
+from pip._internal.utils.misc import (
+    ask,
+    ask_input,
+    ask_password,
+    remove_auth_from_url,
+    split_auth_netloc_from_url,
+)
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from optparse import Values
+    from typing import Dict, Optional, Tuple
+
+    from pip._internal.vcs.versioncontrol import AuthInfo
+
+    Credentials = Tuple[str, str, str]
+
+logger = logging.getLogger(__name__)
+
+try:
+    import keyring  # noqa
+except ImportError:
+    keyring = None
+except Exception as exc:
+    logger.warning(
+        "Keyring is skipped due to an exception: %s", str(exc),
+    )
+    keyring = None
+
+
+def get_keyring_auth(url, username):
+    """Return the tuple auth for a given url from keyring."""
+    if not url or not keyring:
+        return None
+
+    try:
+        try:
+            get_credential = keyring.get_credential
+        except AttributeError:
+            pass
+        else:
+            logger.debug("Getting credentials from keyring for %s", url)
+            cred = get_credential(url, username)
+            if cred is not None:
+                return cred.username, cred.password
+            return None
+
+        if username:
+            logger.debug("Getting password from keyring for %s", url)
+            password = keyring.get_password(url, username)
+            if password:
+                return username, password
+
+    except Exception as exc:
+        logger.warning(
+            "Keyring is skipped due to an exception: %s", str(exc),
+        )
+
+
+class MultiDomainBasicAuth(AuthBase):
+
+    def __init__(self, prompting=True, index_urls=None):
+        # type: (bool, Optional[Values]) -> None
+        self.prompting = prompting
+        self.index_urls = index_urls
+        self.passwords = {}  # type: 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,
+        # this value is set to the credentials they entered. After the
+        # request authenticates, the caller should call
+        # ``save_credentials`` to save these.
+        self._credentials_to_save = None  # type: Optional[Credentials]
+
+    def _get_index_url(self, url):
+        """Return the original index URL matching the requested URL.
+
+        Cached or dynamically generated credentials may work against
+        the original index URL rather than just the netloc.
+
+        The provided url should have had its username and password
+        removed already. If the original index url had credentials then
+        they will be included in the return value.
+
+        Returns None if no matching index was found, or if --no-index
+        was specified by the user.
+        """
+        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
+
+    def _get_new_credentials(self, original_url, allow_netrc=True,
+                             allow_keyring=True):
+        """Find and return credentials for the specified URL."""
+        # Split the credentials and netloc from the url.
+        url, netloc, url_user_password = split_auth_netloc_from_url(
+            original_url,
+        )
+
+        # Start with the credentials embedded in the url
+        username, password = url_user_password
+        if username is not None and password is not None:
+            logger.debug("Found credentials in url for %s", netloc)
+            return url_user_password
+
+        # Find a matching index url for this request
+        index_url = self._get_index_url(url)
+        if index_url:
+            # Split the credentials from the url.
+            index_info = split_auth_netloc_from_url(index_url)
+            if index_info:
+                index_url, _, index_url_user_password = index_info
+                logger.debug("Found index url %s", index_url)
+
+        # If an index URL was found, try its embedded credentials
+        if index_url and index_url_user_password[0] is not None:
+            username, password = index_url_user_password
+            if username is not None and password is not None:
+                logger.debug("Found credentials in index url for %s", netloc)
+                return index_url_user_password
+
+        # Get creds from netrc if we still don't have them
+        if allow_netrc:
+            netrc_auth = get_netrc_auth(original_url)
+            if netrc_auth:
+                logger.debug("Found credentials in netrc for %s", netloc)
+                return netrc_auth
+
+        # If we don't have a password and keyring is available, use it.
+        if allow_keyring:
+            # The index url is more specific than the netloc, so try it first
+            kr_auth = (
+                get_keyring_auth(index_url, username) or
+                get_keyring_auth(netloc, username)
+            )
+            if kr_auth:
+                logger.debug("Found credentials in keyring for %s", netloc)
+                return kr_auth
+
+        return username, password
+
+    def _get_url_and_credentials(self, original_url):
+        """Return the credentials to use for the provided URL.
+
+        If allowed, netrc and keyring may be used to obtain the
+        correct credentials.
+
+        Returns (url_without_credentials, username, password). Note
+        that even if the original URL contains credentials, this
+        function may return a different username and password.
+        """
+        url, netloc, _ = split_auth_netloc_from_url(original_url)
+
+        # Use any stored credentials that we have for this netloc
+        username, password = self.passwords.get(netloc, (None, None))
+
+        if username is None and password is None:
+            # No stored credentials. Acquire new credentials without prompting
+            # the user. (e.g. from netrc, keyring, or the URL itself)
+            username, password = self._get_new_credentials(original_url)
+
+        if username is not None or password is not None:
+            # Convert the username and password if they're None, so that
+            # this netloc will show up as "cached" in the conditional above.
+            # Further, HTTPBasicAuth doesn't accept None, so it makes sense to
+            # cache the value that is going to be used.
+            username = username or ""
+            password = password or ""
+
+            # Store any acquired credentials.
+            self.passwords[netloc] = (username, password)
+
+        assert (
+            # Credentials were found
+            (username is not None and password is not None) or
+            # Credentials were not found
+            (username is None and password is None)
+        ), "Could not load credentials from url: {}".format(original_url)
+
+        return url, username, password
+
+    def __call__(self, req):
+        # Get credentials for this request
+        url, username, password = self._get_url_and_credentials(req.url)
+
+        # Set the url of the request to the url without any credentials
+        req.url = url
+
+        if username is not None and password is not None:
+            # Send the basic auth with this request
+            req = HTTPBasicAuth(username, password)(req)
+
+        # Attach a hook to handle 401 responses
+        req.register_hook("response", self.handle_401)
+
+        return req
+
+    # Factored out to allow for easy patching in tests
+    def _prompt_for_password(self, netloc):
+        username = ask_input("User for %s: " % netloc)
+        if not username:
+            return None, None
+        auth = get_keyring_auth(netloc, username)
+        if auth:
+            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):
+        if not keyring:
+            return False
+        return ask("Save credentials to keyring [y/N]: ", ["y", "n"]) == "y"
+
+    def handle_401(self, resp, **kwargs):
+        # We only care about 401 responses, anything else we want to just
+        #   pass through the actual response
+        if resp.status_code != 401:
+            return resp
+
+        # We are not able to prompt the user so simply return the response
+        if not self.prompting:
+            return resp
+
+        parsed = urllib_parse.urlparse(resp.url)
+
+        # Prompt the user for a new username and password
+        username, password, save = self._prompt_for_password(parsed.netloc)
+
+        # Store the new username and password to use for future requests
+        self._credentials_to_save = None
+        if username is not None and password is not None:
+            self.passwords[parsed.netloc] = (username, password)
+
+            # Prompt to save the password to keyring
+            if save and self._should_save_password_to_keyring():
+                self._credentials_to_save = (parsed.netloc, username, password)
+
+        # Consume content and release the original connection to allow our new
+        #   request to reuse the same one.
+        resp.content
+        resp.raw.release_conn()
+
+        # Add our new username and password to the request
+        req = HTTPBasicAuth(username or "", password or "")(resp.request)
+        req.register_hook("response", self.warn_on_401)
+
+        # On successful request, save the credentials that were used to
+        # keyring. (Note that if the user responded "no" above, this member
+        # is not set and nothing will be saved.)
+        if self._credentials_to_save:
+            req.register_hook("response", self.save_credentials)
+
+        # Send our new request
+        new_resp = resp.connection.send(req, **kwargs)
+        new_resp.history.append(resp)
+
+        return new_resp
+
+    def warn_on_401(self, resp, **kwargs):
+        """Response callback to warn about incorrect credentials."""
+        if resp.status_code == 401:
+            logger.warning(
+                '401 Error, Credentials not correct for %s', resp.request.url,
+            )
+
+    def save_credentials(self, resp, **kwargs):
+        """Response callback to save credentials on success."""
+        assert keyring is not None, "should never reach here without keyring"
+        if not keyring:
+            return
+
+        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)
+            except Exception:
+                logger.exception('Failed to save credentials')