Enable flake8-type-checking

docs/conf.py

@@ -175,6 +175,7 @@
     ('py:class', 'OptionDummy'),  # undocumented
     ('py:class', 'setuptools.dist.Distribution'),  # undocumented
     ('py:class', 'UnixCCompiler'),  # undocumented
+    ('py:class', 'StrPath'),  # type import
     ('py:exc', 'CompileError'),  # undocumented
     ('py:exc', 'DistutilsExecError'),  # undocumented
     ('py:exc', 'DistutilsFileError'),  # undocumented

ruff.toml

@@ -36,6 +36,9 @@ extend-select = [
 	"TRY", # tryceratops
 	"UP", # pyupgrade
 	"YTT", # flake8-2020
+	# Helps prevent circular imports, reduce runtime cost of typing symbols,
+	# and prevent leaking implementations details into modules
+  	"TC", # flake8-type-checking
 ]
 ignore = [
 	# upstream
@@ -67,14 +70,14 @@ ignore = [
 	"UP015", # redundant-open-modes, explicit is preferred
 	# Only enforcing return type annotations for public functions
 	"ANN202", # missing-return-type-private-function
+	# stdlib is not at risk of circular import, is clearly not public API,
+	# and assume it's gonna be included in the import chain at some point anyway 
+  	"TC003", # typing-only-standard-library-import
 ]
 
 [lint.per-file-ignores]
 # Suppress nuisance warnings about module-import-not-at-top-of-file (E402) due to workaround for #4476
 "setuptools/__init__.py" = ["E402"]
-# pkg_resources is due for removal, not worth fixing existing errors
-"pkg_resources/__init__.py" = ["E402", "ANN204"]
-"pkg_resources/tests/test_resources.py" = ["PT031"]
 
 [lint.isort]
 combine-as-imports = true
@@ -89,6 +92,9 @@ sections.delayed = ["distutils"]
 [lint.flake8-annotations]
 ignore-fully-untyped = true
 
+[lint.flake8-type-checking]
+quote-annotations = true
+
 [format]
 # Enable preview to get hugged parenthesis unwrapping and other nice surprises
 # See https://github.com/jaraco/skeleton/pull/133#issuecomment-2239538373

setuptools/command/_requirestxt.py

@@ -13,13 +13,15 @@
 from collections import defaultdict
 from collections.abc import Mapping
 from itertools import filterfalse
-from typing import TypeVar
+from typing import TYPE_CHECKING, TypeVar
 
 from jaraco.text import yield_lines
 from packaging.requirements import Requirement
 
 from .. import _reqs
-from .._reqs import _StrOrIter
+
+if TYPE_CHECKING:
+    from .._reqs import _StrOrIter
 
 # dict can work as an ordered set
 _T = TypeVar("_T")

setuptools/command/bdist_rpm.py

@@ -1,8 +1,14 @@
-from ..dist import Distribution
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
 from ..warnings import SetuptoolsDeprecationWarning
 
 import distutils.command.bdist_rpm as orig
 
+if TYPE_CHECKING:
+    from ..dist import Distribution
+
 
 class bdist_rpm(orig.bdist_rpm):
     """

setuptools/command/bdist_wheel.py

@@ -16,7 +16,7 @@
 from collections.abc import Iterable, Sequence
 from email.generator import BytesGenerator
 from glob import iglob
-from typing import Literal, cast
+from typing import TYPE_CHECKING, Literal, cast
 from zipfile import ZIP_DEFLATED, ZIP_STORED
 
 from packaging import tags, version as _packaging_version
@@ -26,10 +26,12 @@
 from .._core_metadata import _safe_license_file
 from .._normalization import safer_name
 from ..warnings import SetuptoolsDeprecationWarning
-from .egg_info import egg_info as egg_info_cls
 
 from distutils import log
 
+if TYPE_CHECKING:
+    from .egg_info import egg_info as egg_info_cls
+
 
 def safe_version(version: str) -> str:
     """
@@ -233,7 +235,9 @@ def finalize_options(self) -> None:
             self.bdist_dir = os.path.join(bdist_base, "wheel")
 
         if self.dist_info_dir is None:
-            egg_info = cast(egg_info_cls, self.distribution.get_command_obj("egg_info"))
+            egg_info = cast(
+                "egg_info_cls", self.distribution.get_command_obj("egg_info")
+            )
             egg_info.ensure_finalized()  # needed for correct `wheel_dist_name`
 
         self.data_dir = self.wheel_dist_name + ".data"
@@ -492,7 +496,7 @@ def license_paths(self) -> Iterable[str]:
         metadata = self.distribution.get_option_dict("metadata")
         if setuptools_major_version >= 42:
             # Setuptools recognizes the license_files option but does not do globbing
-            patterns = cast(Sequence[str], self.distribution.metadata.license_files)
+            patterns = cast("Sequence[str]", self.distribution.metadata.license_files)
         else:
             # Prior to those, wheel is entirely responsible for handling license files
             if "license_files" in metadata:

setuptools/command/build.py

@@ -1,11 +1,12 @@
 from __future__ import annotations
 
-from typing import Protocol
-
-from ..dist import Distribution
+from typing import TYPE_CHECKING, Protocol
 
 from distutils.command.build import build as _build
 
+if TYPE_CHECKING:
+    from ..dist import Distribution
+
 _ORIGINAL_SUBCOMMANDS = {"build_py", "build_clib", "build_ext", "build_scripts"}
 
 

setuptools/command/build_clib.py

@@ -1,10 +1,16 @@
-from ..dist import Distribution
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
 from ..modified import newer_pairwise_group
 
 import distutils.command.build_clib as orig
 from distutils import log
 from distutils.errors import DistutilsSetupError
 
+if TYPE_CHECKING:
+    from ..dist import Distribution
+
 
 class build_clib(orig.build_clib):
     """

setuptools/command/build_ext.py

@@ -11,7 +11,6 @@
 from pathlib import Path
 from typing import TYPE_CHECKING
 
-from setuptools.dist import Distribution
 from setuptools.errors import BaseError
 from setuptools.extension import Extension, Library
 
@@ -20,6 +19,8 @@
 from distutils.sysconfig import customize_compiler, get_config_var
 
 if TYPE_CHECKING:
+    from setuptools.dist import Distribution
+
     # Cython not installed on CI tests, causing _build_ext to be `Any`
     from distutils.command.build_ext import build_ext as _build_ext
 else:

setuptools/command/build_py.py

@@ -10,18 +10,20 @@
 from functools import partial
 from glob import glob
 from pathlib import Path
-from typing import Any
+from typing import TYPE_CHECKING, Any
 
 from more_itertools import unique_everseen
 
-from .._path import StrPath, StrPathT
-from ..dist import Distribution
 from ..warnings import SetuptoolsDeprecationWarning
 
 import distutils.command.build_py as orig
 import distutils.errors
 from distutils.util import convert_path
 
+if TYPE_CHECKING:
+    from .._path import StrPath, StrPathT
+    from ..dist import Distribution
+
 _IMPLICIT_DATA_FILES = ('*.pyi', 'py.typed')
 
 

setuptools/command/develop.py

@@ -31,7 +31,7 @@ class develop(Command):
     def run(self) -> None:
         # Casting because mypy doesn't understand bool mult conditionals
         cmd = cast(
-            list[str],
+            "list[str]",
             [sys.executable, '-m', 'pip', 'install', '-e', '.', '--use-pep517']
             + ['--target', self.install_dir] * bool(self.install_dir)
             + ['--no-deps'] * self.no_deps

setuptools/command/dist_info.py

@@ -7,15 +7,17 @@
 import shutil
 from contextlib import contextmanager
 from pathlib import Path
-from typing import cast
+from typing import TYPE_CHECKING, cast
 
 from .. import _normalization
 from .._shutil import rmdir as _rm
-from .egg_info import egg_info as egg_info_cls
 
 from distutils import log
 from distutils.core import Command
 
+if TYPE_CHECKING:
+    from .egg_info import egg_info as egg_info_cls
+
 
 class dist_info(Command):
     """
@@ -54,7 +56,7 @@ def finalize_options(self) -> None:
         project_dir = dist.src_root or os.curdir
         self.output_dir = Path(self.output_dir or project_dir)
 
-        egg_info = cast(egg_info_cls, self.reinitialize_command("egg_info"))
+        egg_info = cast("egg_info_cls", self.reinitialize_command("egg_info"))
         egg_info.egg_base = str(self.output_dir)
 
         if self.tag_date:

setuptools/command/editable_wheel.py

@@ -29,24 +29,25 @@
 from typing import TYPE_CHECKING, Protocol, TypeVar, cast
 
 from .. import Command, _normalization, _path, _shutil, errors, namespaces
-from .._path import StrPath
 from ..compat import py310, py312
 from ..discovery import find_package_path
-from ..dist import Distribution
 from ..warnings import InformationOnly, SetuptoolsDeprecationWarning
-from .build import build as build_cls
 from .build_py import build_py as build_py_cls
-from .dist_info import dist_info as dist_info_cls
-from .egg_info import egg_info as egg_info_cls
-from .install import install as install_cls
-from .install_scripts import install_scripts as install_scripts_cls
 
 if TYPE_CHECKING:
     from typing_extensions import Self
 
+    from .._path import StrPath
     from .._vendor.wheel.wheelfile import WheelFile
+    from ..dist import Distribution
+    from .build import build as build_cls
+    from .dist_info import dist_info as dist_info_cls
+    from .egg_info import egg_info as egg_info_cls
+    from .install import install as install_cls
+    from .install_scripts import install_scripts as install_scripts_cls
+
+    _P = TypeVar("_P", bound=StrPath)
 
-_P = TypeVar("_P", bound=StrPath)
 _logger = logging.getLogger(__name__)
 
 
@@ -150,7 +151,7 @@ def run(self) -> None:
 
     def _ensure_dist_info(self):
         if self.dist_info_dir is None:
-            dist_info = cast(dist_info_cls, self.reinitialize_command("dist_info"))
+            dist_info = cast("dist_info_cls", self.reinitialize_command("dist_info"))
             dist_info.output_dir = self.dist_dir
             dist_info.ensure_finalized()
             dist_info.run()
@@ -198,16 +199,17 @@ def _configure_build(
 
         # egg-info may be generated again to create a manifest (used for package data)
         egg_info = cast(
-            egg_info_cls, dist.reinitialize_command("egg_info", reinit_subcommands=True)
+            "egg_info_cls",
+            dist.reinitialize_command("egg_info", reinit_subcommands=True),
         )
         egg_info.egg_base = str(tmp_dir)
         egg_info.ignore_egg_info_in_manifest = True
 
         build = cast(
-            build_cls, dist.reinitialize_command("build", reinit_subcommands=True)
+            "build_cls", dist.reinitialize_command("build", reinit_subcommands=True)
         )
         install = cast(
-            install_cls, dist.reinitialize_command("install", reinit_subcommands=True)
+            "install_cls", dist.reinitialize_command("install", reinit_subcommands=True)
         )
 
         build.build_platlib = build.build_purelib = build.build_lib = build_lib
@@ -222,13 +224,13 @@ def _configure_build(
         build_scripts.executable = 'python'
 
         install_scripts = cast(
-            install_scripts_cls, dist.get_command_obj("install_scripts")
+            "install_scripts_cls", dist.get_command_obj("install_scripts")
         )
         install_scripts.no_ep = True
 
         build.build_temp = str(tmp_dir)
 
-        build_py = cast(build_py_cls, dist.get_command_obj("build_py"))
+        build_py = cast("build_py_cls", dist.get_command_obj("build_py"))
         build_py.compile = False
         build_py.existing_egg_info_dir = self._find_egg_info_dir()
 

setuptools/command/install.py

@@ -5,17 +5,13 @@
 from collections.abc import Callable
 from typing import TYPE_CHECKING, Any, ClassVar
 
-from ..dist import Distribution
 from ..warnings import SetuptoolsDeprecationWarning, SetuptoolsWarning
 
 import distutils.command.install as orig
 from distutils.errors import DistutilsArgError
 
 if TYPE_CHECKING:
-    # This is only used for a type-cast, don't import at runtime or it'll cause deprecation warnings
-    from .easy_install import easy_install as easy_install_cls
-else:
-    easy_install_cls = None
+    from ..dist import Distribution
 
 
 def __getattr__(name: str):  # pragma: no cover

setuptools/command/install_lib.py

@@ -3,12 +3,14 @@
 import os
 import sys
 from itertools import product, starmap
-
-from .._path import StrPath
-from ..dist import Distribution
+from typing import TYPE_CHECKING
 
 import distutils.command.install_lib as orig
 
+if TYPE_CHECKING:
+    from .._path import StrPath
+    from ..dist import Distribution
+
 
 class install_lib(orig.install_lib):
     """Don't add compiled flags to filenames of non-Python files"""

setuptools/command/install_scripts.py

@@ -2,13 +2,16 @@
 
 import os
 import sys
+from typing import TYPE_CHECKING
 
 from .._path import ensure_directory
-from ..dist import Distribution
 
 import distutils.command.install_scripts as orig
 from distutils import log
 
+if TYPE_CHECKING:
+    from ..dist import Distribution
+
 
 class install_scripts(orig.install_scripts):
     """Do normal script install, plus any egg_info wrapper scripts"""

setuptools/command/sdist.py

@@ -5,15 +5,17 @@
 import re
 from collections.abc import Iterator
 from itertools import chain
-from typing import ClassVar
+from typing import TYPE_CHECKING, ClassVar
 
 from .._importlib import metadata
-from ..dist import Distribution
 from .build import _ORIGINAL_SUBCOMMANDS
 
 import distutils.command.sdist as orig
 from distutils import log
 
+if TYPE_CHECKING:
+    from ..dist import Distribution
+
 _default_revctrl = list
 
 

setuptools/config/__init__.py

@@ -36,7 +36,7 @@ def _wrapper(*args, **kwargs):
         )
         return fn(*args, **kwargs)
 
-    return cast(Fn, _wrapper)
+    return cast("Fn", _wrapper)
 
 
 read_configuration = _deprecation_notice(setupcfg.read_configuration)