Strict typing (#103)

Author: Dreamsorcerer

.codecov.yml

@@ -2,7 +2,7 @@
 
 codecov:
   notify:
-    after_n_builds: 23  # The number of test matrix+lint jobs uploading coverage
+    after_n_builds: 20  # The number of test matrix+lint jobs uploading coverage
     wait_for_ci: false
 
   require_ci_to_pass: false

.github/workflows/reusable-linters.yml

@@ -71,10 +71,7 @@ jobs:
       with:
         token: ${{ secrets.codecov-token }}
         files: >-
-          .tox/.tmp/.mypy/python-3.13/cobertura.xml,
-          .tox/.tmp/.mypy/python-3.12/cobertura.xml,
-          .tox/.tmp/.mypy/python-3.11/cobertura.xml,
-          .tox/.tmp/.mypy/python-3.9/cobertura.xml
+          .tox/.tmp/.mypy/python-3.11/cobertura.xml
         flags: >-
           CI-GHA,
           MyPy

.mypy.ini

@@ -1,46 +1,28 @@
 [mypy]
-python_version = 3.9
-color_output = true
-error_summary = true
-files =
-  packaging/,
-  tests/,
-  src/propcache/
-
-# check_untyped_defs = true
-
-# disallow_untyped_calls = true
-# disallow_untyped_defs = true
-# disallow_any_generics = true
-
-enable_error_code =
-  ignore-without-code
-
-follow_imports = normal
-
-ignore_missing_imports = false
-
-pretty = true
-
-show_column_numbers = true
-show_error_codes = true
-strict_optional = true
-
-warn_no_return = true
-warn_redundant_casts = true
-warn_unused_ignores = true
-
-[mypy-Cython.*]
-ignore_missing_imports = true
-
-[mypy-distutils.*]
-ignore_missing_imports = true
-
-[mypy-expandvars]
-ignore_missing_imports = true
-
-[mypy-pytest]
-ignore_missing_imports = true
-
-[mypy-tomllib]
-ignore_missing_imports = true
+files = packaging, src, tests
+check_untyped_defs = True
+follow_imports_for_stubs = True
+disallow_any_decorated = True
+disallow_any_generics = True
+disallow_any_unimported = True
+disallow_incomplete_defs = True
+disallow_subclassing_any = True
+disallow_untyped_calls = True
+disallow_untyped_decorators = True
+disallow_untyped_defs = True
+# TODO(PY312): explicit-override
+enable_error_code = deprecated, ignore-without-code, possibly-undefined, redundant-expr, redundant-self, truthy-bool, truthy-iterable, unused-awaitable
+extra_checks = True
+follow_untyped_imports = True
+implicit_reexport = False
+no_implicit_optional = True
+pretty = True
+show_column_numbers = True
+show_error_codes = True
+show_error_code_links = True
+strict_equality = True
+warn_incomplete_stub = True
+warn_redundant_casts = True
+warn_return_any = True
+warn_unreachable = True
+warn_unused_ignores = True

.pre-commit-config.yaml

@@ -109,40 +109,12 @@ repos:
 - repo: https://github.com/pre-commit/mirrors-mypy.git
   rev: v1.14.1
   hooks:
-  - id: mypy
-    alias: mypy-py313
-    name: MyPy, for Python 3.13
-    additional_dependencies:
-    - lxml  # dep of `--txt-report`, `--cobertura-xml-report` & `--html-report`
-    - pytest
-    - pytest_codspeed==3.0.0
-    - tomli  # requirement of packaging/pep517_backend/
-    - types-setuptools  # requirement of packaging/pep517_backend/
-    args:
-    - --python-version=3.13
-    - --txt-report=.tox/.tmp/.mypy/python-3.13
-    - --cobertura-xml-report=.tox/.tmp/.mypy/python-3.13
-    - --html-report=.tox/.tmp/.mypy/python-3.13
-    pass_filenames: false
-  - id: mypy
-    alias: mypy-py312
-    name: MyPy, for Python 3.12
-    additional_dependencies:
-    - lxml  # dep of `--txt-report`, `--cobertura-xml-report` & `--html-report`
-    - pytest
-    - pytest_codspeed==3.0.0
-    - tomli  # requirement of packaging/pep517_backend/
-    - types-setuptools  # requirement of packaging/pep517_backend/
-    args:
-    - --python-version=3.12
-    - --txt-report=.tox/.tmp/.mypy/python-3.12
-    - --cobertura-xml-report=.tox/.tmp/.mypy/python-3.12
-    - --html-report=.tox/.tmp/.mypy/python-3.12
-    pass_filenames: false
   - id: mypy
     alias: mypy-py311
     name: MyPy, for Python 3.11
     additional_dependencies:
+    - Cython
+    - expandvars
     - lxml  # dep of `--txt-report`, `--cobertura-xml-report` & `--html-report`
     - pytest
     - pytest_codspeed==3.0.0
@@ -156,23 +128,6 @@ repos:
     - --cobertura-xml-report=.tox/.tmp/.mypy/python-3.11
     - --html-report=.tox/.tmp/.mypy/python-3.11
     pass_filenames: false
-  - id: mypy
-    alias: mypy-py39
-    name: MyPy, for Python 3.9
-    additional_dependencies:
-    - lxml  # dep of `--txt-report`, `--cobertura-xml-report` & `--html-report`
-    - pytest
-    - pytest_codspeed==3.0.0
-    - tomli  # requirement of packaging/pep517_backend/
-    - types-setuptools  # requirement of packaging/pep517_backend/
-    - types-Pygments
-    - types-colorama
-    args:
-    - --python-version=3.9
-    - --txt-report=.tox/.tmp/.mypy/python-3.9
-    - --cobertura-xml-report=.tox/.tmp/.mypy/python-3.9
-    - --html-report=.tox/.tmp/.mypy/python-3.9
-    pass_filenames: false
 
 - repo: https://github.com/rhysd/actionlint.git
   rev: v1.7.6

CHANGES/103.bugfix.rst

@@ -0,0 +1,2 @@
+Improved typing annotations, fixing some type errors under correct usage
+and improving typing robustness generally -- by :user:`Dreamsorcerer`.

packaging/pep517_backend/_backend.py

@@ -6,6 +6,7 @@
 import os
 import sysconfig
 import typing as t
+from collections.abc import Iterator
 from contextlib import contextmanager, nullcontext, suppress
 from functools import partial
 from pathlib import Path
@@ -56,7 +57,7 @@
     'get_requires_for_build_wheel',
     'prepare_metadata_for_build_wheel',
     *(
-        () if _setuptools_build_editable is None
+        () if _setuptools_build_editable is None  # type: ignore[redundant-expr]
         else (
             'build_editable',
             'get_requires_for_build_editable',
@@ -87,7 +88,7 @@
 """A fallback for ``pure-python`` is not set."""
 
 
-def _is_truthy_setting_value(setting_value) -> bool:
+def _is_truthy_setting_value(setting_value: str) -> bool:
     truthy_values = {'', None, 'true', '1', 'on'}
     return setting_value.lower() in truthy_values
 
@@ -108,7 +109,7 @@ def _get_setting_value(
             continue
 
         with suppress(lookup_errors):  # type: ignore[arg-type]
-            return _is_truthy_setting_value(src_mapping[src_key])  # type: ignore[index]
+            return _is_truthy_setting_value(src_mapping[src_key])  # type: ignore[arg-type,index]
 
     return default
 
@@ -125,7 +126,7 @@ def _make_pure_python(config_settings: _ConfigDict | None = None) -> bool:
 def _include_cython_line_tracing(
         config_settings: _ConfigDict | None = None,
         *,
-        default=False,
+        default: bool = False,
 ) -> bool:
     return _get_setting_value(
         config_settings,
@@ -136,60 +137,61 @@ def _include_cython_line_tracing(
 
 
 @contextmanager
-def patched_distutils_cmd_install():
+def patched_distutils_cmd_install() -> Iterator[None]:
     """Make `install_lib` of `install` cmd always use `platlib`.
 
     :yields: None
     """
     # Without this, build_lib puts stuff under `*.data/purelib/` folder
     orig_finalize = _distutils_install_cmd.finalize_options
 
-    def new_finalize_options(self):  # noqa: WPS430
+    def new_finalize_options(self: _distutils_install_cmd) -> None:
         self.install_lib = self.install_platlib
         orig_finalize(self)
 
-    _distutils_install_cmd.finalize_options = new_finalize_options
+    _distutils_install_cmd.finalize_options = new_finalize_options  # type: ignore[method-assign]
     try:
         yield
     finally:
-        _distutils_install_cmd.finalize_options = orig_finalize
+        _distutils_install_cmd.finalize_options = orig_finalize  # type: ignore[method-assign]
 
 
 @contextmanager
-def patched_dist_has_ext_modules():
+def patched_dist_has_ext_modules() -> Iterator[None]:
     """Make `has_ext_modules` of `Distribution` always return `True`.
 
     :yields: None
     """
     # Without this, build_lib puts stuff under `*.data/platlib/` folder
     orig_func = _DistutilsDistribution.has_ext_modules
 
-    _DistutilsDistribution.has_ext_modules = lambda *args, **kwargs: True
+    _DistutilsDistribution.has_ext_modules = lambda *args, **kwargs: True  # type: ignore[method-assign]
     try:
         yield
     finally:
-        _DistutilsDistribution.has_ext_modules = orig_func
+        _DistutilsDistribution.has_ext_modules = orig_func  # type: ignore[method-assign]
 
 
 @contextmanager
-def patched_dist_get_long_description():
+def patched_dist_get_long_description() -> Iterator[None]:
     """Make `has_ext_modules` of `Distribution` always return `True`.
 
     :yields: None
     """
     # Without this, build_lib puts stuff under `*.data/platlib/` folder
     _orig_func = _DistutilsDistributionMetadata.get_long_description
 
-    def _get_sanitized_long_description(self):
+    def _get_sanitized_long_description(self: _DistutilsDistributionMetadata) -> str:
+        assert self.long_description is not None
         return sanitize_rst_roles(self.long_description)
 
-    _DistutilsDistributionMetadata.get_long_description = (
+    _DistutilsDistributionMetadata.get_long_description = (  # type: ignore[method-assign]
         _get_sanitized_long_description
     )
     try:
         yield
     finally:
-        _DistutilsDistributionMetadata.get_long_description = _orig_func
+        _DistutilsDistributionMetadata.get_long_description = _orig_func  # type: ignore[method-assign]
 
 
 def _exclude_dir_path(
@@ -293,7 +295,7 @@ def maybe_prebuild_c_extensions(
 
         cythonize_args = _make_cythonize_cli_args_from_config(config)
         with _patched_cython_env(config['env'], cython_line_tracing_requested):
-            _cythonize_cli_cmd(cythonize_args)
+            _cythonize_cli_cmd(cythonize_args)  # type: ignore[no-untyped-call]
         with patched_distutils_cmd_install():
             with patched_dist_has_ext_modules():
                 yield

packaging/pep517_backend/_compat.py

@@ -1,17 +1,20 @@
 """Cross-python stdlib shims."""
 
 import os
-import typing as t
+import sys
+from collections.abc import Iterator
 from contextlib import contextmanager
 from pathlib import Path
 
 # isort: off
-try:
-    from contextlib import chdir as chdir_cm  # type: ignore[attr-defined, unused-ignore] # noqa: E501
-except ImportError:
+if sys.version_info >= (3, 11):
+    from contextlib import chdir as chdir_cm
+    from tomllib import loads as load_toml_from_string
+else:
+    from tomli import loads as load_toml_from_string
 
-    @contextmanager  # type: ignore[no-redef, unused-ignore]
-    def chdir_cm(path: os.PathLike) -> t.Iterator[None]:
+    @contextmanager
+    def chdir_cm(path: os.PathLike) -> Iterator[None]:
         """Temporarily change the current directory, recovering on exit."""
         original_wd = Path.cwd()
         os.chdir(path)
@@ -22,12 +25,4 @@ def chdir_cm(path: os.PathLike) -> t.Iterator[None]:
 
 
 # isort: on
-
-
-try:
-    from tomllib import loads as load_toml_from_string
-except ImportError:
-    from tomli import loads as load_toml_from_string
-
-
 __all__ = ("chdir_cm", "load_toml_from_string")  # noqa: WPS410

packaging/pep517_backend/_cython_configuration.py

@@ -3,17 +3,26 @@
 from __future__ import annotations
 
 import os
+from collections.abc import Iterator
 from contextlib import contextmanager
 from pathlib import Path
 from sys import version_info as _python_version_tuple
+from typing import TypedDict
 
 from expandvars import expandvars
 
 from ._compat import load_toml_from_string
 from ._transformers import get_cli_kwargs_from_config, get_enabled_cli_flags_from_config
 
 
-def get_local_cython_config() -> dict:
+class Config(TypedDict):
+    env: dict[str, str]
+    flags: dict[str, bool]
+    kwargs: dict[str, str]
+    src: list[str]
+
+
+def get_local_cython_config() -> Config:
     """Grab optional build dependencies from pyproject.toml config.
 
     :returns: config section from ``pyproject.toml``
@@ -67,10 +76,10 @@ def get_local_cython_config() -> dict:
     """
     config_toml_txt = (Path.cwd().resolve() / 'pyproject.toml').read_text()
     config_mapping = load_toml_from_string(config_toml_txt)
-    return config_mapping['tool']['local']['cythonize']
+    return config_mapping['tool']['local']['cythonize']  # type: ignore[no-any-return]
 
 
-def make_cythonize_cli_args_from_config(config) -> list[str]:
+def make_cythonize_cli_args_from_config(config: Config) -> list[str]:
     py_ver_arg = f'-{_python_version_tuple.major!s}'
 
     cli_flags = get_enabled_cli_flags_from_config(config['flags'])
@@ -80,7 +89,7 @@ def make_cythonize_cli_args_from_config(config) -> list[str]:
 
 
 @contextmanager
-def patched_env(env: dict[str, str], cython_line_tracing_requested: bool):
+def patched_env(env: dict[str, str], cython_line_tracing_requested: bool) -> Iterator[None]:
     """Temporary set given env vars.
 
     :param env: tmp env vars to set
@@ -89,7 +98,7 @@ def patched_env(env: dict[str, str], cython_line_tracing_requested: bool):
     :yields: None
     """
     orig_env = os.environ.copy()
-    expanded_env = {name: expandvars(var_val) for name, var_val in env.items()}
+    expanded_env = {name: expandvars(var_val) for name, var_val in env.items()}  # type: ignore[no-untyped-call]
     os.environ.update(expanded_env)
 
     if cython_line_tracing_requested: