Eliminate base_command.py's dependence on PipSession

src/pip/_internal/cli/base_command.py

@@ -1,8 +1,5 @@
 """Base Command class, and related routines"""
 
-# The following comment should be removed at some point in the future.
-# mypy: strict-optional=False
-
 from __future__ import absolute_import, print_function
 
 import logging
@@ -25,7 +22,6 @@
     UNKNOWN_ERROR,
     VIRTUALENV_NOT_FOUND,
 )
-from pip._internal.download import PipSession
 from pip._internal.exceptions import (
     BadCommand,
     CommandError,
@@ -35,13 +31,12 @@
 )
 from pip._internal.utils.deprecation import deprecated
 from pip._internal.utils.logging import BrokenStdoutLoggingError, setup_logging
-from pip._internal.utils.misc import get_prog, normalize_path
-from pip._internal.utils.outdated import pip_version_check
+from pip._internal.utils.misc import get_prog
 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 Optional, List, Tuple, Any
+    from typing import List, Tuple, Any
     from optparse import Values
 
 __all__ = ['Command']
@@ -50,15 +45,14 @@
 
 
 class Command(object):
-    name = None  # type: Optional[str]
-    usage = None  # type: Optional[str]
+    usage = None  # type: str
     ignore_require_venv = False  # type: bool
 
     def __init__(self, name, summary, isolated=False):
         # type: (str, str, bool) -> None
         parser_kw = {
             'usage': self.usage,
-            'prog': '%s %s' % (get_prog(), self.name),
+            'prog': '%s %s' % (get_prog(), name),
             'formatter': UpdatingDefaultsHelpFormatter(),
             'add_help_option': False,
             'name': name,
@@ -81,62 +75,20 @@ def __init__(self, name, summary, isolated=False):
         )
         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
 
-    @classmethod
-    def _get_index_urls(cls, options):
-        """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 _build_session(self, options, retries=None, timeout=None):
-        # type: (Values, Optional[int], Optional[int]) -> PipSession
-        session = PipSession(
-            cache=(
-                normalize_path(os.path.join(options.cache_dir, "http"))
-                if options.cache_dir else None
-            ),
-            retries=retries if retries is not None else options.retries,
-            insecure_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
-
     def parse_args(self, args):
         # type: (List[str]) -> Tuple
         # factored out for testability
@@ -226,21 +178,7 @@ def main(self, args):
 
             return UNKNOWN_ERROR
         finally:
-            allow_version_check = (
-                # Does this command have the index_group options?
-                hasattr(options, "no_index") and
-                # Is this command allowed to perform this check?
-                not (options.disable_pip_version_check or options.no_index)
-            )
-            # Check if we're using the latest version of pip available
-            if allow_version_check:
-                session = self._build_session(
-                    options,
-                    retries=0,
-                    timeout=min(5, options.timeout)
-                )
-                with session:
-                    pip_version_check(session, options)
+            self.handle_pip_version_check(options)
 
             # Shutdown the logging module
             logging.shutdown()

src/pip/_internal/cli/req_command.py

@@ -1,12 +1,15 @@
-"""Contains the RequirementCommand base class.
+"""Contains the Command base classes that depend on PipSession.
 
-This is in a separate module so that Command classes not inheriting from
-RequirementCommand don't need to import e.g. the PackageFinder machinery
-and all its vendored dependencies.
+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 os
+
 from pip._internal.cli.base_command import Command
 from pip._internal.cli.cmdoptions import make_search_scope
+from pip._internal.download import PipSession
 from pip._internal.exceptions import CommandError
 from pip._internal.index import PackageFinder
 from pip._internal.legacy_resolve import Resolver
@@ -17,28 +20,119 @@
     install_req_from_line,
 )
 from pip._internal.req.req_file import parse_requirements
+from pip._internal.utils.misc import normalize_path
+from pip._internal.utils.outdated import pip_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.download import PipSession
     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
 
 
-class RequirementCommand(Command):
+class SessionCommandMixin(object):
+
+    """
+    A class mixin for command classes needing _build_session().
+    """
+
+    @classmethod
+    def _get_index_urls(cls, options):
+        """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 _build_session(self, options, retries=None, timeout=None):
+        # type: (Values, Optional[int], Optional[int]) -> PipSession
+        session = PipSession(
+            cache=(
+                normalize_path(os.path.join(options.cache_dir, "http"))
+                if options.cache_dir else None
+            ),
+            retries=retries if retries is not None else options.retries,
+            insecure_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(SessionCommandMixin, Command):
+
+    """
+    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_version_check(session, options)
+
+
+class RequirementCommand(IndexGroupCommand):
 
     @staticmethod
     def make_requirement_preparer(
-            temp_directory,           # type: TempDirectory
-            options,                  # type: Values
-            req_tracker,              # type: RequirementTracker
-            download_dir=None,        # type: str
-            wheel_download_dir=None,  # type: str
+        temp_directory,           # type: TempDirectory
+        options,                  # type: Values
+        req_tracker,              # type: RequirementTracker
+        download_dir=None,        # type: str
+        wheel_download_dir=None,  # type: str
     ):
         # type: (...) -> RequirementPreparer
         """
@@ -56,18 +150,18 @@ def make_requirement_preparer(
 
     @staticmethod
     def make_resolver(
-            preparer,                            # type: RequirementPreparer
-            session,                             # type: PipSession
-            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, ...]]
+        preparer,                            # type: RequirementPreparer
+        session,                             # type: PipSession
+        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
         """
@@ -90,14 +184,15 @@ def make_resolver(
         )
 
     @staticmethod
-    def populate_requirement_set(requirement_set,  # type: RequirementSet
-                                 args,             # type: List[str]
-                                 options,          # type: Values
-                                 finder,           # type: PackageFinder
-                                 session,          # type: PipSession
-                                 name,             # type: str
-                                 wheel_cache       # type: Optional[WheelCache]
-                                 ):
+    def populate_requirement_set(
+        requirement_set,  # type: RequirementSet
+        args,             # type: List[str]
+        options,          # type: Values
+        finder,           # type: PackageFinder
+        session,          # type: PipSession
+        name,             # type: str
+        wheel_cache,      # type: Optional[WheelCache]
+    ):
         # type: (...) -> None
         """
         Marshal cmd line args into a requirement set.

src/pip/_internal/commands/list.py

@@ -7,8 +7,8 @@
 from pip._vendor.six.moves import zip_longest
 
 from pip._internal.cli import cmdoptions
-from pip._internal.cli.base_command import Command
 from pip._internal.cli.cmdoptions import make_search_scope
+from pip._internal.cli.req_command import IndexGroupCommand
 from pip._internal.exceptions import CommandError
 from pip._internal.index import PackageFinder
 from pip._internal.models.selection_prefs import SelectionPreferences
@@ -21,7 +21,7 @@
 logger = logging.getLogger(__name__)
 
 
-class ListCommand(Command):
+class ListCommand(IndexGroupCommand):
     """
     List installed packages, including editables.
 

src/pip/_internal/commands/search.py

@@ -12,6 +12,7 @@
 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.download import PipXmlrpcTransport
 from pip._internal.exceptions import CommandError
@@ -22,7 +23,7 @@
 logger = logging.getLogger(__name__)
 
 
-class SearchCommand(Command):
+class SearchCommand(SessionCommandMixin, Command):
     """Search for PyPI packages whose name or summary contains <query>."""
 
     usage = """