--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/python3.8/site-packages/pip/_internal/vcs/mercurial.py	Mon Jul 27 03:47:31 2020 -0400
@@ -0,0 +1,155 @@
+# 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._vendor.six.moves import configparser
+
+from pip._internal.exceptions import BadCommand, InstallationError
+from pip._internal.utils.misc import display_path
+from pip._internal.utils.subprocess import make_command
+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
+from pip._internal.vcs.versioncontrol import (
+    VersionControl,
+    find_path_to_setup_from_repo_root,
+    vcs,
+)
+
+if MYPY_CHECK_RUNNING:
+    from pip._internal.utils.misc import HiddenText
+    from pip._internal.vcs.versioncontrol import RevOptions
+
+
+logger = logging.getLogger(__name__)
+
+
+class Mercurial(VersionControl):
+    name = 'hg'
+    dirname = '.hg'
+    repo_name = 'clone'
+    schemes = (
+        'hg', 'hg+file', 'hg+http', 'hg+https', 'hg+ssh', 'hg+static-http',
+    )
+
+    @staticmethod
+    def get_base_rev_args(rev):
+        return [rev]
+
+    def export(self, location, url):
+        # type: (str, HiddenText) -> None
+        """Export the Hg repository at the url to the destination location"""
+        with TempDirectory(kind="export") as temp_dir:
+            self.unpack(temp_dir.path, url=url)
+
+            self.run_command(
+                ['archive', location], show_stdout=False, cwd=temp_dir.path
+            )
+
+    def fetch_new(self, dest, url, rev_options):
+        # type: (str, HiddenText, RevOptions) -> None
+        rev_display = rev_options.to_display()
+        logger.info(
+            'Cloning hg %s%s to %s',
+            url,
+            rev_display,
+            display_path(dest),
+        )
+        self.run_command(make_command('clone', '--noupdate', '-q', url, dest))
+        self.run_command(
+            make_command('update', '-q', rev_options.to_args()),
+            cwd=dest,
+        )
+
+    def switch(self, dest, url, rev_options):
+        # type: (str, HiddenText, RevOptions) -> None
+        repo_config = os.path.join(dest, self.dirname, 'hgrc')
+        config = configparser.RawConfigParser()
+        try:
+            config.read(repo_config)
+            config.set('paths', 'default', url.secret)
+            with open(repo_config, 'w') as config_file:
+                config.write(config_file)
+        except (OSError, configparser.NoSectionError) as exc:
+            logger.warning(
+                'Could not switch Mercurial repository to %s: %s', url, exc,
+            )
+        else:
+            cmd_args = make_command('update', '-q', rev_options.to_args())
+            self.run_command(cmd_args, cwd=dest)
+
+    def update(self, dest, url, rev_options):
+        # type: (str, HiddenText, RevOptions) -> None
+        self.run_command(['pull', '-q'], cwd=dest)
+        cmd_args = make_command('update', '-q', rev_options.to_args())
+        self.run_command(cmd_args, cwd=dest)
+
+    @classmethod
+    def get_remote_url(cls, location):
+        url = cls.run_command(
+            ['showconfig', 'paths.default'],
+            show_stdout=False, cwd=location).strip()
+        if cls._is_local_repository(url):
+            url = path_to_url(url)
+        return url.strip()
+
+    @classmethod
+    def get_revision(cls, location):
+        """
+        Return the repository-local changeset revision number, as an integer.
+        """
+        current_revision = cls.run_command(
+            ['parents', '--template={rev}'],
+            show_stdout=False, cwd=location).strip()
+        return current_revision
+
+    @classmethod
+    def get_requirement_revision(cls, location):
+        """
+        Return the changeset identification hash, as a 40-character
+        hexadecimal string
+        """
+        current_rev_hash = cls.run_command(
+            ['parents', '--template={node}'],
+            show_stdout=False, cwd=location).strip()
+        return current_rev_hash
+
+    @classmethod
+    def is_commit_id_equal(cls, dest, name):
+        """Always assume the versions don't match"""
+        return False
+
+    @classmethod
+    def get_subdirectory(cls, location):
+        """
+        Return the path to setup.py, relative to the repo root.
+        Return None if setup.py is in the repo root.
+        """
+        # find the repo root
+        repo_root = cls.run_command(
+            ['root'], show_stdout=False, cwd=location).strip()
+        if not os.path.isabs(repo_root):
+            repo_root = os.path.abspath(os.path.join(location, repo_root))
+        return find_path_to_setup_from_repo_root(location, repo_root)
+
+    @classmethod
+    def controls_location(cls, location):
+        if super(Mercurial, cls).controls_location(location):
+            return True
+        try:
+            cls.run_command(
+                ['identify'],
+                cwd=location,
+                show_stdout=False,
+                on_returncode='raise',
+                log_failed_cmd=False)
+            return True
+        except (BadCommand, InstallationError):
+            return False
+
+
+vcs.register(Mercurial)