From 845634da23761afb7993e7e3edf6aaf39d3658f0 Mon Sep 17 00:00:00 2001
From: Daniel Hollas <daniel.hollas@bristol.ac.uk>
Date: Mon, 5 Jan 2026 11:58:51 +0100
Subject: [PATCH 1/5] Avoid importing metadata module in autocompletion

---
 src/pip/_internal/cli/autocompletion.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/pip/_internal/cli/autocompletion.py b/src/pip/_internal/cli/autocompletion.py
index f22cd1159a2..8add031618e 100644
--- a/src/pip/_internal/cli/autocompletion.py
+++ b/src/pip/_internal/cli/autocompletion.py
@@ -11,7 +11,6 @@
 
 from pip._internal.cli.main_parser import create_main_parser
 from pip._internal.commands import commands_dict, create_command
-from pip._internal.metadata import get_default_environment
 
 
 def autocomplete() -> None:
@@ -51,6 +50,8 @@ def autocomplete() -> None:
             "uninstall",
         ]
         if should_list_installed:
+            from pip._internal.metadata import get_default_environment
+
             env = get_default_environment()
             lc = current.lower()
             installed = [

From c2e2f7935cc494fbadc4c53a858b6bf12de151ce Mon Sep 17 00:00:00 2001
From: Daniel Hollas <daniel.hollas@bristol.ac.uk>
Date: Mon, 5 Jan 2026 12:03:52 +0100
Subject: [PATCH 2/5] Move get_runnable_pip

---
 src/pip/_internal/build_env.py       | 19 +------------------
 src/pip/_internal/cli/main_parser.py |  3 +--
 src/pip/_internal/utils/misc.py      | 18 ++++++++++++++++++
 3 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/src/pip/_internal/build_env.py b/src/pip/_internal/build_env.py
index f28d862f279..50f2badbeff 100644
--- a/src/pip/_internal/build_env.py
+++ b/src/pip/_internal/build_env.py
@@ -4,7 +4,6 @@
 
 import logging
 import os
-import pathlib
 import site
 import sys
 import textwrap
@@ -15,12 +14,12 @@
 
 from pip._vendor.packaging.version import Version
 
-from pip import __file__ as pip_location
 from pip._internal.cli.spinners import open_spinner
 from pip._internal.locations import get_platlib, get_purelib, get_scheme
 from pip._internal.metadata import get_default_environment, get_environment
 from pip._internal.utils.deprecation import deprecated
 from pip._internal.utils.logging import VERBOSE
+from pip._internal.utils.misc import get_runnable_pip
 from pip._internal.utils.packaging import get_requirement
 from pip._internal.utils.subprocess import call_subprocess
 from pip._internal.utils.temp_dir import TempDirectory, tempdir_kinds
@@ -49,22 +48,6 @@ def __init__(self, path: str) -> None:
         self.lib_dirs = _dedup(scheme.purelib, scheme.platlib)
 
 
-def get_runnable_pip() -> str:
-    """Get a file to pass to a Python executable, to run the currently-running pip.
-
-    This is used to run a pip subprocess, for installing requirements into the build
-    environment.
-    """
-    source = pathlib.Path(pip_location).resolve().parent
-
-    if not source.is_dir():
-        # This would happen if someone is using pip from inside a zip file. In that
-        # case, we can use that directly.
-        return str(source)
-
-    return os.fsdecode(source / "__pip-runner__.py")
-
-
 def _get_system_sitepackages() -> set[str]:
     """Get system site packages
 
diff --git a/src/pip/_internal/cli/main_parser.py b/src/pip/_internal/cli/main_parser.py
index 5ce9f5a02d4..7c7fb1806e0 100644
--- a/src/pip/_internal/cli/main_parser.py
+++ b/src/pip/_internal/cli/main_parser.py
@@ -6,12 +6,11 @@
 import subprocess
 import sys
 
-from pip._internal.build_env import get_runnable_pip
 from pip._internal.cli import cmdoptions
 from pip._internal.cli.parser import ConfigOptionParser, UpdatingDefaultsHelpFormatter
 from pip._internal.commands import commands_dict, get_similar_commands
 from pip._internal.exceptions import CommandError
-from pip._internal.utils.misc import get_pip_version, get_prog
+from pip._internal.utils.misc import get_pip_version, get_prog, get_runnable_pip
 
 __all__ = ["create_main_parser", "parse_command"]
 
diff --git a/src/pip/_internal/utils/misc.py b/src/pip/_internal/utils/misc.py
index 66e521bbc1b..ac718a2383f 100644
--- a/src/pip/_internal/utils/misc.py
+++ b/src/pip/_internal/utils/misc.py
@@ -5,6 +5,7 @@
 import hashlib
 import logging
 import os
+import pathlib
 import posixpath
 import shutil
 import stat
@@ -31,6 +32,7 @@
 from pip._vendor.packaging.requirements import Requirement
 from pip._vendor.pyproject_hooks import BuildBackendHookCaller
 
+from pip import __file__ as pip_location
 from pip import __version__
 from pip._internal.exceptions import CommandError, ExternallyManagedEnvironment
 from pip._internal.locations import get_major_minor_version
@@ -74,6 +76,22 @@ def get_pip_version() -> str:
     return f"pip {__version__} from {pip_pkg_dir} (python {get_major_minor_version()})"
 
 
+def get_runnable_pip() -> str:
+    """Get a file to pass to a Python executable, to run the currently-running pip.
+
+    This is used to run a pip subprocess, for installing requirements into the build
+    environment.
+    """
+    source = pathlib.Path(pip_location).resolve().parent
+
+    if not source.is_dir():
+        # This would happen if someone is using pip from inside a zip file. In that
+        # case, we can use that directly.
+        return str(source)
+
+    return os.fsdecode(source / "__pip-runner__.py")
+
+
 def normalize_version_info(py_version_info: tuple[int, ...]) -> tuple[int, int, int]:
     """
     Convert a tuple of ints representing a Python version to one of length

From f88e8666be39187520fe29607cd605c17a533bd9 Mon Sep 17 00:00:00 2001
From: Daniel Hollas <daniel.hollas@bristol.ac.uk>
Date: Mon, 5 Jan 2026 12:35:26 +0100
Subject: [PATCH 3/5] Avoid importing packaging.requirements module during tab
 autocompletion

---
 src/pip/_internal/exceptions.py | 5 ++++-
 src/pip/_internal/utils/misc.py | 5 ++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/pip/_internal/exceptions.py b/src/pip/_internal/exceptions.py
index 8bcb46212f8..1cc79faff47 100644
--- a/src/pip/_internal/exceptions.py
+++ b/src/pip/_internal/exceptions.py
@@ -18,7 +18,6 @@
 from itertools import chain, groupby, repeat
 from typing import TYPE_CHECKING, Literal
 
-from pip._vendor.packaging.requirements import InvalidRequirement
 from pip._vendor.packaging.version import InvalidVersion
 from pip._vendor.rich.console import Console, ConsoleOptions, RenderResult
 from pip._vendor.rich.markup import escape
@@ -27,6 +26,7 @@
 if TYPE_CHECKING:
     from hashlib import _Hash
 
+    from pip._vendor.packaging.requirements import InvalidRequirement
     from pip._vendor.requests.models import PreparedRequest, Request, Response
 
     from pip._internal.metadata import BaseDistribution
@@ -809,6 +809,9 @@ def __init__(
         dist: BaseDistribution,
         invalid_exc: InvalidRequirement | InvalidVersion,
     ) -> None:
+        # packaging.requirements module is slow to import
+        from pip._vendor.packaging.requirements import InvalidRequirement
+
         installed_location = dist.installed_location
 
         if isinstance(invalid_exc, InvalidRequirement):
diff --git a/src/pip/_internal/utils/misc.py b/src/pip/_internal/utils/misc.py
index ac718a2383f..327f288428f 100644
--- a/src/pip/_internal/utils/misc.py
+++ b/src/pip/_internal/utils/misc.py
@@ -20,6 +20,7 @@
 from pathlib import Path
 from types import FunctionType, TracebackType
 from typing import (
+    TYPE_CHECKING,
     Any,
     BinaryIO,
     Callable,
@@ -29,7 +30,6 @@
     cast,
 )
 
-from pip._vendor.packaging.requirements import Requirement
 from pip._vendor.pyproject_hooks import BuildBackendHookCaller
 
 from pip import __file__ as pip_location
@@ -40,6 +40,9 @@
 from pip._internal.utils.retry import retry
 from pip._internal.utils.virtualenv import running_under_virtualenv
 
+if TYPE_CHECKING:
+    from pip._vendor.packaging.requirements import Requirement
+
 __all__ = [
     "rmtree",
     "display_path",

From 612660ba85e9b04696ded2e11c60f6545c474dc5 Mon Sep 17 00:00:00 2001
From: Daniel Hollas <daniel.hollas@bristol.ac.uk>
Date: Mon, 5 Jan 2026 12:40:07 +0100
Subject: [PATCH 4/5] Add news entry

---
 news/4768.feature.rst | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 news/4768.feature.rst

diff --git a/news/4768.feature.rst b/news/4768.feature.rst
new file mode 100644
index 00000000000..a41818ad2f8
--- /dev/null
+++ b/news/4768.feature.rst
@@ -0,0 +1 @@
+Speedup tab autocompletion by lazy-importing certain modules.

From d1011798f04ca86a928b7697afb268f7c5b0fa7e Mon Sep 17 00:00:00 2001
From: Daniel Hollas <daniel.hollas@bristol.ac.uk>
Date: Tue, 13 Jan 2026 18:11:09 +0000
Subject: [PATCH 5/5] Revert "Avoid importing packaging.requirements module
 during tab autocompletion"

This reverts commit f88e8666be39187520fe29607cd605c17a533bd9.
---
 src/pip/_internal/exceptions.py | 5 +----
 src/pip/_internal/utils/misc.py | 5 +----
 2 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/src/pip/_internal/exceptions.py b/src/pip/_internal/exceptions.py
index ab0584ac001..4d4e012cc8c 100644
--- a/src/pip/_internal/exceptions.py
+++ b/src/pip/_internal/exceptions.py
@@ -19,6 +19,7 @@
 from itertools import chain, groupby, repeat
 from typing import TYPE_CHECKING, Literal
 
+from pip._vendor.packaging.requirements import InvalidRequirement
 from pip._vendor.packaging.version import InvalidVersion
 from pip._vendor.rich.console import Console, ConsoleOptions, RenderResult
 from pip._vendor.rich.markup import escape
@@ -27,7 +28,6 @@
 if TYPE_CHECKING:
     from hashlib import _Hash
 
-    from pip._vendor.packaging.requirements import InvalidRequirement
     from pip._vendor.requests.models import PreparedRequest, Request, Response
 
     from pip._internal.metadata import BaseDistribution
@@ -810,9 +810,6 @@ def __init__(
         dist: BaseDistribution,
         invalid_exc: InvalidRequirement | InvalidVersion,
     ) -> None:
-        # packaging.requirements module is slow to import
-        from pip._vendor.packaging.requirements import InvalidRequirement
-
         installed_location = dist.installed_location
 
         if isinstance(invalid_exc, InvalidRequirement):
diff --git a/src/pip/_internal/utils/misc.py b/src/pip/_internal/utils/misc.py
index 327f288428f..ac718a2383f 100644
--- a/src/pip/_internal/utils/misc.py
+++ b/src/pip/_internal/utils/misc.py
@@ -20,7 +20,6 @@
 from pathlib import Path
 from types import FunctionType, TracebackType
 from typing import (
-    TYPE_CHECKING,
     Any,
     BinaryIO,
     Callable,
@@ -30,6 +29,7 @@
     cast,
 )
 
+from pip._vendor.packaging.requirements import Requirement
 from pip._vendor.pyproject_hooks import BuildBackendHookCaller
 
 from pip import __file__ as pip_location
@@ -40,9 +40,6 @@
 from pip._internal.utils.retry import retry
 from pip._internal.utils.virtualenv import running_under_virtualenv
 
-if TYPE_CHECKING:
-    from pip._vendor.packaging.requirements import Requirement
-
 __all__ = [
     "rmtree",
     "display_path",