Typecheck using pyright

pyrightconfig.json

@@ -0,0 +1,31 @@
+{
+	"$schema": "https://raw.githubusercontent.com/microsoft/pyright/main/packages/vscode-pyright/schemas/pyrightconfig.schema.json",
+	"exclude": [
+		"build",
+		".tox",
+		"**/extern", // Vendored
+		"**/_vendor", // Vendored
+		"setuptools/_distutils", // Vendored
+		"**/tests", // Disabled as long as analyzeUnannotatedFunctions=false to reduce log spam
+		"**/_*", // Disabled as long as analyzeUnannotatedFunctions=false to reduce log spam
+	],
+	// CI should test for all versions, local development gets hints for oldest supported
+	"pythonVersion": "3.8",
+	// For now we don't mind if mypy's `type: ignore` comments accidentally suppresses pyright issues
+	"enableTypeIgnoreComments": true,
+	"typeCheckingMode": "basic",
+	// For now, align with mypy's default of skipping unnanotated functions, only care about public API which should be annotated
+	"analyzeUnannotatedFunctions": false,
+	// TODO: Test environment is not yet properly configured to install all imported packages
+	"reportMissingImports": "none",
+	// Too many issues caused by vendoring and dynamic patching, still worth fixing when we can
+	"reportAttributeAccessIssue": "warning",
+	// Defered initialization (initialize_options/finalize_options) causes many "potentially None" issues
+	// TODO: Fix with type-guards or by changing how it's initialized
+	"reportCallIssue": "warning",
+	"reportArgumentType": "warning",
+	"reportOptionalIterable": "warning",
+	"reportOptionalMemberAccess": "warning",
+	"reportGeneralTypeIssues": "warning",
+	"reportOptionalOperand": "warning",
+}

setup.cfg

@@ -73,6 +73,7 @@ testing =
 	# for tools/finalize.py
 	jaraco.develop >= 7.21; python_version >= "3.9" and sys_platform != "cygwin"
 	pytest-home >= 0.5
+	pyright
 	# No Python 3.12 dependencies require importlib_metadata, but we need it for type-checking
 	importlib_metadata; python_version >= "3.12"
 	trove_classifiers

setuptools/command/build.py

@@ -98,12 +98,15 @@ def finalize_options(self):
 
     def initialize_options(self):
         """(Required by the original :class:`setuptools.Command` interface)"""
+        ...
 
     def finalize_options(self):
         """(Required by the original :class:`setuptools.Command` interface)"""
+        ...
 
     def run(self):
         """(Required by the original :class:`setuptools.Command` interface)"""
+        ...
 
     def get_source_files(self) -> List[str]:
         """
@@ -115,6 +118,7 @@ def get_source_files(self) -> List[str]:
         with all the files necessary to build the distribution.
         All files should be strings relative to the project root directory.
         """
+        ...
 
     def get_outputs(self) -> List[str]:
         """
@@ -128,6 +132,7 @@ def get_outputs(self) -> List[str]:
            in ``get_output_mapping()`` plus files that are generated during the build
            and don't correspond to any source file already present in the project.
         """
+        ...
 
     def get_output_mapping(self) -> Dict[str, str]:
         """
@@ -138,3 +143,4 @@ def get_output_mapping(self) -> Dict[str, str]:
         Destination files should be strings in the form of
         ``"{build_lib}/destination/file/path"``.
         """
+        ...

setuptools/command/easy_install.py

@@ -2012,7 +2012,7 @@ def is_python_script(script_text, filename):
 
 
 try:
-    from os import chmod as _chmod
+    from os import chmod as _chmod  # pyright: ignore[reportAssignmentType] # Loosing type-safety w/ pyright, but that's ok
 except ImportError:
     # Jython compatibility
     def _chmod(*args: object, **kwargs: object) -> None:  # type: ignore[misc] # Mypy re-uses the imported definition anyway

setuptools/config/pyprojecttoml.py

@@ -297,7 +297,10 @@ def _obtain(self, dist: "Distribution", field: str, package_dir: Mapping[str, st
     def _obtain_version(self, dist: "Distribution", package_dir: Mapping[str, str]):
         # Since plugins can set version, let's silently skip if it cannot be obtained
         if "version" in self.dynamic and "version" in self.dynamic_cfg:
-            return _expand.version(self._obtain(dist, "version", package_dir))
+            return _expand.version(
+                # We already do an early check for the presence of "version"
+                self._obtain(dist, "version", package_dir)  # pyright: ignore[reportArgumentType]
+            )
         return None
 
     def _obtain_readme(self, dist: "Distribution") -> Optional[Dict[str, str]]:
@@ -307,9 +310,10 @@ def _obtain_readme(self, dist: "Distribution") -> Optional[Dict[str, str]]:
         dynamic_cfg = self.dynamic_cfg
         if "readme" in dynamic_cfg:
             return {
+                # We already do an early check for the presence of "readme"
                 "text": self._obtain(dist, "readme", {}),
                 "content-type": dynamic_cfg["readme"].get("content-type", "text/x-rst"),
-            }
+            }  # pyright: ignore[reportReturnType]
 
         self._ensure_previously_set(dist, "readme")
         return None

setuptools/monkey.py

@@ -8,12 +8,14 @@
 import sys
 import types
 from importlib import import_module
-from typing import List, TypeVar
+from typing import List, Optional, Type, TypeVar, Union, cast, overload
 
 import distutils.filelist
 
 
 _T = TypeVar("_T")
+_UnpatchT = TypeVar("_UnpatchT", type, types.FunctionType)
+
 
 __all__: List[str] = []
 """
@@ -36,25 +38,30 @@ def _get_mro(cls):
     return inspect.getmro(cls)
 
 
-def get_unpatched(item: _T) -> _T:
-    lookup = (
-        get_unpatched_class
-        if isinstance(item, type)
-        else get_unpatched_function
-        if isinstance(item, types.FunctionType)
-        else lambda item: None
-    )
-    return lookup(item)
+@overload
+def get_unpatched(item: _UnpatchT) -> _UnpatchT: ...  # type: ignore[overload-overlap]
+@overload
+def get_unpatched(item: object) -> None: ...
+def get_unpatched(
+    item: Union[type, types.FunctionType, object],
+) -> Optional[Union[type, types.FunctionType]]:
+    if isinstance(item, type):
+        return get_unpatched_class(item)
+    if isinstance(item, types.FunctionType):
+        return get_unpatched_function(item)
+    return None
 
 
-def get_unpatched_class(cls):
+def get_unpatched_class(cls: Type[_T]) -> Type[_T]:
     """Protect against re-patching the distutils if reloaded
 
     Also ensures that no other distutils extension monkeypatched the distutils
     first.
     """
     external_bases = (
-        cls for cls in _get_mro(cls) if not cls.__module__.startswith('setuptools')
+        cast(Type[_T], cls)
+        for cls in _get_mro(cls)
+        if not cls.__module__.startswith('setuptools')
     )
     base = next(external_bases)
     if not base.__module__.startswith('distutils'):

tox.ini

@@ -7,6 +7,7 @@ setenv =
 	SETUPTOOLS_ENFORCE_DEPRECATION = {env:SETUPTOOLS_ENFORCE_DEPRECATION:0}
 	# ^-- Temporarily disable enforcement so CI don't fail on due dates
 commands =
+	pyright .
 	pytest --mypy {posargs}
 usedevelop = True
 extras =