Re-enable mypy and sync mypy.ini from skeleton

mypy.ini

@@ -1,17 +1,27 @@
 [mypy]
-# CI should test for all versions, local development gets hints for oldest supported
-# But our testing setup doesn't allow passing CLI arguments, so local devs have to set this manually.
-# python_version = 3.8
+## upstream
+
+# Is the project well-typed?
 strict = False
+
+# Early opt-in even when strict = False
 warn_unused_ignores = True
 warn_redundant_casts = True
-# required to support namespace packages: https://github.com/python/mypy/issues/14057
+enable_error_code = ignore-without-code
+
+# Support namespace packages per https://github.com/python/mypy/issues/14057
 explicit_package_bases = True
 
 disable_error_code =
 	# Disable due to many false positives
 	overload-overlap,
 
+## local
+
+# CI should test for all versions, local development gets hints for oldest supported
+# But our testing setup doesn't allow passing CLI arguments, so local devs have to set this manually.
+# python_version = 3.8
+
 exclude = (?x)(
 	# Avoid scanning Python files in generated folders
 	^build/
@@ -54,6 +64,6 @@ ignore_missing_imports = True
 
 # Even when excluding a module, import issues can show up due to following import
 # https://github.com/python/mypy/issues/11936#issuecomment-1466764006
-[mypy-setuptools.config._validate_pyproject.*,setuptools._distutils.*]
+[mypy-setuptools.config._validate_pyproject.*,setuptools._vendor.*,setuptools._distutils.*]
 follow_imports = silent
 # silent => ignore errors when following imports

pkg_resources/__init__.py

@@ -2777,7 +2777,7 @@ def load(
         if require:
             # We could pass `env` and `installer` directly,
             # but keeping `*args` and `**kwargs` for backwards compatibility
-            self.require(*args, **kwargs)  # type: ignore
+            self.require(*args, **kwargs)  # type: ignore[arg-type]
         return self.resolve()
 
     def resolve(self) -> _ResolvedEntryPoint:

pyproject.toml

@@ -216,7 +216,3 @@ formats = "zip"
 
 
 [tool.setuptools_scm]
-
-
-[tool.pytest-enabler.mypy]
-# Disabled due to jaraco/skeleton#143

setuptools/config/expand.py

@@ -203,7 +203,8 @@ def _load_spec(spec: ModuleSpec, module_name: str) -> ModuleType:
         return sys.modules[name]
     module = importlib.util.module_from_spec(spec)
     sys.modules[name] = module  # cache (it also ensures `==` works on loaded items)
-    spec.loader.exec_module(module)  # type: ignore
+    assert spec.loader is not None
+    spec.loader.exec_module(module)
     return module
 
 
@@ -285,10 +286,11 @@ def find_packages(
 
     from setuptools.discovery import construct_package_dir
 
-    if namespaces:
-        from setuptools.discovery import PEP420PackageFinder as PackageFinder
+    # check "not namespaces" first due to python/mypy#6232
+    if not namespaces:
+        from setuptools.discovery import PackageFinder
     else:
-        from setuptools.discovery import PackageFinder  # type: ignore
+        from setuptools.discovery import PEP420PackageFinder as PackageFinder
 
     root_dir = root_dir or os.curdir
     where = kwargs.pop('where', ['.'])
@@ -359,7 +361,8 @@ def entry_points(text: str, text_source="entry-points") -> dict[str, dict]:
     entry-point names, and the second level values are references to objects
     (that correspond to the entry-point value).
     """
-    parser = ConfigParser(default_section=None, delimiters=("=",))  # type: ignore
+    # Using undocumented behaviour, see python/typeshed#12700
+    parser = ConfigParser(default_section=None, delimiters=("=",))  # type: ignore[call-overload]
     parser.optionxform = str  # case sensitive
     parser.read_string(text, text_source)
     groups = {k: dict(v.items()) for k, v in parser.items()}

setuptools/config/pyprojecttoml.py

@@ -44,8 +44,8 @@ def validate(config: dict, filepath: StrPath) -> bool:
 
     trove_classifier = validator.FORMAT_FUNCTIONS.get("trove-classifier")
     if hasattr(trove_classifier, "_disable_download"):
-        # Improve reproducibility by default. See issue 31 for validate-pyproject.
-        trove_classifier._disable_download()  # type: ignore
+        # Improve reproducibility by default. See abravalheri/validate-pyproject#31
+        trove_classifier._disable_download()  # type: ignore[union-attr]
 
     try:
         return validator.validate(config)

setuptools/config/setupcfg.py

@@ -27,7 +27,6 @@
     List,
     Tuple,
     TypeVar,
-    Union,
     cast,
 )
 
@@ -53,7 +52,7 @@
 while the second element of the tuple is the option value itself
 """
 AllCommandOptions = Dict["str", SingleCommandOptions]  # cmd name => its options
-Target = TypeVar("Target", bound=Union["Distribution", "DistributionMetadata"])
+Target = TypeVar("Target", "Distribution", "DistributionMetadata")
 
 
 def read_configuration(
@@ -96,7 +95,7 @@ def _apply(
     filepath: StrPath,
     other_files: Iterable[StrPath] = (),
     ignore_option_errors: bool = False,
-) -> tuple[ConfigHandler, ...]:
+) -> tuple[ConfigMetadataHandler, ConfigOptionsHandler]:
     """Read configuration from ``filepath`` and applies to the ``dist`` object."""
     from setuptools.dist import _Distribution
 
@@ -122,7 +121,7 @@ def _apply(
     return handlers
 
 
-def _get_option(target_obj: Target, key: str):
+def _get_option(target_obj: Distribution | DistributionMetadata, key: str):
     """
     Given a target object and option key, get that option from
     the target object, either through a get_{key} method or
@@ -134,10 +133,14 @@ def _get_option(target_obj: Target, key: str):
     return getter()
 
 
-def configuration_to_dict(handlers: tuple[ConfigHandler, ...]) -> dict:
+def configuration_to_dict(
+    handlers: Iterable[
+        ConfigHandler[Distribution] | ConfigHandler[DistributionMetadata]
+    ],
+) -> dict:
     """Returns configuration data gathered by given handlers as a dict.
 
-    :param list[ConfigHandler] handlers: Handlers list,
+    :param Iterable[ConfigHandler] handlers: Handlers list,
         usually from parse_configuration()
 
     :rtype: dict
@@ -254,7 +257,7 @@ def __init__(
         ensure_discovered: expand.EnsurePackagesDiscovered,
     ):
         self.ignore_option_errors = ignore_option_errors
-        self.target_obj = target_obj
+        self.target_obj: Target = target_obj
         self.sections = dict(self._section_options(options))
         self.set_options: list[str] = []
         self.ensure_discovered = ensure_discovered

setuptools/msvc.py

@@ -1418,7 +1418,7 @@ def VCRuntimeRedist(self) -> str | None:
             os.path.join(prefix, arch_subdir, crt_dir, vcruntime)
             for (prefix, crt_dir) in itertools.product(prefixes, crt_dirs)
         )
-        return next(filter(os.path.isfile, candidate_paths), None)
+        return next(filter(os.path.isfile, candidate_paths), None)  # type: ignore[arg-type] #python/mypy#12682
 
     def return_env(self, exists=True):
         """

setuptools/tests/config/test_setupcfg.py

@@ -7,7 +7,7 @@
 import pytest
 from packaging.requirements import InvalidRequirement
 
-from setuptools.config.setupcfg import ConfigHandler, read_configuration
+from setuptools.config.setupcfg import ConfigHandler, Target, read_configuration
 from setuptools.dist import Distribution, _Distribution
 from setuptools.warnings import SetuptoolsDeprecationWarning
 
@@ -16,7 +16,7 @@
 from distutils.errors import DistutilsFileError, DistutilsOptionError
 
 
-class ErrConfigHandler(ConfigHandler):
+class ErrConfigHandler(ConfigHandler[Target]):
     """Erroneous handler. Fails to implement required methods."""
 
     section_prefix = "**err**"

setuptools/tests/test_build_ext.py

@@ -183,7 +183,7 @@ def get_build_ext_cmd(self, optional: bool, **opts):
             "eggs.c": "#include missingheader.h\n",
             ".build": {"lib": {}, "tmp": {}},
         }
-        path.build(files)  # type: ignore[arg-type] # jaraco/path#232
+        path.build(files)  # jaraco/path#232
         extension = Extension('spam.eggs', ['eggs.c'], optional=optional)
         dist = Distribution(dict(ext_modules=[extension]))
         dist.script_name = 'setup.py'

setuptools/tests/test_editable_install.py

@@ -878,18 +878,18 @@ class TestOverallBehaviour:
             "otherfile.py": "",
             "mypkg": {
                 "__init__.py": "",
-                "mod1.py": FLAT_LAYOUT["mypkg"]["mod1.py"],  # type: ignore
+                "mod1.py": FLAT_LAYOUT["mypkg"]["mod1.py"],  # type: ignore[index] # Would need a TypedDict
             },
-            "other": FLAT_LAYOUT["mypkg"]["subpackage"],  # type: ignore
+            "other": FLAT_LAYOUT["mypkg"]["subpackage"],  # type: ignore[index] # Would need a TypedDict
         },
         "namespace": {
             "pyproject.toml": dedent(PYPROJECT),
             "MANIFEST.in": EXAMPLE["MANIFEST.in"],
             "otherfile.py": "",
             "src": {
                 "mypkg": {
-                    "mod1.py": FLAT_LAYOUT["mypkg"]["mod1.py"],  # type: ignore
-                    "subpackage": FLAT_LAYOUT["mypkg"]["subpackage"],  # type: ignore
+                    "mod1.py": FLAT_LAYOUT["mypkg"]["mod1.py"],  # type: ignore[index] # Would need a TypedDict
+                    "subpackage": FLAT_LAYOUT["mypkg"]["subpackage"],  # type: ignore[index] # Would need a TypedDict
                 },
             },
         },