Use pre-commit for linting (#607)

Author: AlexWaygood

.github/workflows/ci.yml

@@ -81,27 +81,6 @@ jobs:
           # because we monkeypatch typing under some circumstances.
           python -c 'import typing_extensions; import test.__main__' test_typing -v
 
-  linting:
-    name: Lint
-
-    # no reason to run this as a cron job
-    if: github.event_name != 'schedule'
-
-    runs-on: ubuntu-latest
-
-    steps:
-      - uses: actions/checkout@v4
-      - name: Set up Python
-        uses: actions/setup-python@v5
-        with:
-          python-version: "3"
-          cache: "pip"
-          cache-dependency-path: "test-requirements.txt"
-      - name: Install dependencies
-        run: pip install -r test-requirements.txt
-      - name: Lint implementation
-        run: ruff check
-
   create-issue-on-failure:
     name: Create an issue if daily tests failed
     runs-on: ubuntu-latest

.pre-commit-config.yaml

@@ -0,0 +1,35 @@
+repos:
+  - repo: https://github.com/astral-sh/ruff-pre-commit
+    rev: v0.9.6
+    hooks:
+      - id: ruff
+        args: [--fix, --exit-non-zero-on-fix]
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.5.0
+    hooks:
+      - id: trailing-whitespace
+      - id: end-of-file-fixer
+      - id: check-docstring-first
+      - id: check-yaml
+      - id: check-toml
+      - id: check-merge-conflict
+      - id: check-case-conflict
+      - id: forbid-submodules
+      - id: mixed-line-ending
+        args: [--fix=lf]
+  - repo: https://github.com/python-jsonschema/check-jsonschema
+    rev: 0.33.0
+    hooks:
+      - id: check-dependabot
+  - repo: https://github.com/abravalheri/validate-pyproject
+    rev: v0.24.1
+    hooks:
+      - id: validate-pyproject
+        additional_dependencies: ["validate-pyproject-schema-store[all]"]
+  - repo: https://github.com/rhysd/actionlint
+    rev: v1.7.7
+    hooks:
+      - id: actionlint
+  - repo: meta
+    hooks:
+      - id: check-hooks-apply

.readthedocs.yaml

@@ -10,4 +10,3 @@ build:
 
 sphinx:
   configuration: doc/conf.py
-

CONTRIBUTING.md

@@ -51,6 +51,31 @@ Running these commands in the `src/` directory ensures that the local file
 `typing_extensions.py` is used, instead of any other version of the library you
 may have installed.
 
+# Linting
+
+Linting is done via pre-commit. We recommend running pre-commit via a tool such
+as [uv](https://docs.astral.sh/uv/) or [pipx](https://pipx.pypa.io/stable/) so
+that pre-commit and its dependencies are installed into an isolated environment
+located outside your `typing_extensions` clone. Running pre-commit this way
+ensures that you don't accidentally install a version of `typing_extensions`
+from PyPI into a virtual environment inside your `typing_extensions` clone,
+which could easily happen if pre-commit depended (directly or indirectly) on
+`typing_extensions`. If a version of `typing_extensions` from PyPI *was*
+installed into a project-local virtual environment, it could lead to
+unpredictable results when running `typing_extensions` tests locally.
+
+To run the linters using uv:
+
+```
+uvx pre-commit run -a
+```
+
+Or using pipx:
+
+```
+pipx run pre-commit run -a
+```
+
 # Workflow for PyPI releases
 
 - Make sure you follow the versioning policy in the documentation

doc/make.bat

@@ -1,35 +1,35 @@
-@ECHO OFF
-
-pushd %~dp0
-
-REM Command file for Sphinx documentation
-
-if "%SPHINXBUILD%" == "" (
-	set SPHINXBUILD=sphinx-build
-)
-set SOURCEDIR=.
-set BUILDDIR=_build
-
-%SPHINXBUILD% >NUL 2>NUL
-if errorlevel 9009 (
-	echo.
-	echo.The 'sphinx-build' command was not found. Make sure you have Sphinx
-	echo.installed, then set the SPHINXBUILD environment variable to point
-	echo.to the full path of the 'sphinx-build' executable. Alternatively you
-	echo.may add the Sphinx directory to PATH.
-	echo.
-	echo.If you don't have Sphinx installed, grab it from
-	echo.https://www.sphinx-doc.org/
-	exit /b 1
-)
-
-if "%1" == "" goto help
-
-%SPHINXBUILD% -M %1 %SOURCEDIR% %BUILDDIR% %SPHINXOPTS% %O%
-goto end
-
-:help
-%SPHINXBUILD% -M help %SOURCEDIR% %BUILDDIR% %SPHINXOPTS% %O%
-
-:end
-popd
+@ECHO OFF
+
+pushd %~dp0
+
+REM Command file for Sphinx documentation
+
+if "%SPHINXBUILD%" == "" (
+	set SPHINXBUILD=sphinx-build
+)
+set SOURCEDIR=.
+set BUILDDIR=_build
+
+%SPHINXBUILD% >NUL 2>NUL
+if errorlevel 9009 (
+	echo.
+	echo.The 'sphinx-build' command was not found. Make sure you have Sphinx
+	echo.installed, then set the SPHINXBUILD environment variable to point
+	echo.to the full path of the 'sphinx-build' executable. Alternatively you
+	echo.may add the Sphinx directory to PATH.
+	echo.
+	echo.If you don't have Sphinx installed, grab it from
+	echo.https://www.sphinx-doc.org/
+	exit /b 1
+)
+
+if "%1" == "" goto help
+
+%SPHINXBUILD% -M %1 %SOURCEDIR% %BUILDDIR% %SPHINXOPTS% %O%
+goto end
+
+:help
+%SPHINXBUILD% -M help %SOURCEDIR% %BUILDDIR% %SPHINXOPTS% %O%
+
+:end
+popd