[3.11] Trim trailing whitespace and test on CI (GH-104275) (#108215)

.github/CODEOWNERS

@@ -5,7 +5,10 @@
 # https://git-scm.com/docs/gitignore#_pattern_format
 
 # GitHub
-.github/**                    @ezio-melotti
+.github/**                    @ezio-melotti @hugovk
+
+# pre-commit
+.pre-commit-config.yaml       @hugovk @AlexWaygood
 
 # asyncio
 **/*asyncio*                  @1st1 @asvetlov

.github/workflows/lint.yml

@@ -0,0 +1,22 @@
+name: Lint
+
+on: [push, pull_request, workflow_dispatch]
+
+permissions:
+  contents: read
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
+        with:
+          python-version: "3.x"
+      - uses: pre-commit/action@v3.0.0

.pre-commit-config.yaml

@@ -0,0 +1,7 @@
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.4.0
+    hooks:
+      - id: check-yaml
+      - id: trailing-whitespace
+        types_or: [c, python, rst]

Lib/test/test_isinstance.py

@@ -8,7 +8,6 @@ import typing
 from test import support
 
 
-
 class TestIsInstanceExceptions(unittest.TestCase):
     # Test to make sure that an AttributeError when accessing the instance's
     # class's bases is masked.  This was actually a bug in Python 2.2 and
@@ -97,7 +96,7 @@ class TestIsInstanceExceptions(unittest.TestCase):
         class D: pass
         self.assertRaises(RuntimeError, isinstance, c, D)
 
-
+
 # These tests are similar to above, but tickle certain code paths in
 # issubclass() instead of isinstance() -- really PyObject_IsSubclass()
 # vs. PyObject_IsInstance().
@@ -147,7 +146,6 @@ class TestIsSubclassExceptions(unittest.TestCase):
         self.assertRaises(TypeError, issubclass, B, C())
 
 
-
 # meta classes for creating abstract classes and instances
 class AbstractClass(object):
     def __init__(self, bases):
@@ -179,7 +177,7 @@ class Super:
 
 class Child(Super):
     pass
-
+
 class TestIsInstanceIsSubclass(unittest.TestCase):
     # Tests to ensure that isinstance and issubclass work on abstract
     # classes and instances.  Before the 2.2 release, TypeErrors were
@@ -357,6 +355,6 @@ def blowstack(fxn, arg, compare_to):
         tuple_arg = (tuple_arg,)
         fxn(arg, tuple_arg)
 
-
+
 if __name__ == '__main__':
     unittest.main()

Modules/_io/_iomodule.c

@@ -59,7 +59,7 @@ PyDoc_STRVAR(module_doc,
 "   I/O classes. open() uses the file's blksize (as obtained by os.stat) if\n"
 "   possible.\n"
     );
-
+
 
 /*
  * The main open() function
@@ -512,7 +512,7 @@ _io_open_code_impl(PyObject *module, PyObject *path)
 {
     return PyFile_OpenCodeObject(path);
 }
-
+
 /*
  * Private helpers for the io module.
  */