Support checking executable bit without Git.

pre_commit_hooks/check_shebang_scripts_are_executable.py

@@ -2,20 +2,38 @@
 from __future__ import annotations
 
 import argparse
+import os
 import shlex
 import sys
 from typing import Sequence
 
 from pre_commit_hooks.check_executables_have_shebangs import EXECUTABLE_VALUES
 from pre_commit_hooks.check_executables_have_shebangs import git_ls_files
 from pre_commit_hooks.check_executables_have_shebangs import has_shebang
+from pre_commit_hooks.util import cmd_output
 
 
 def check_shebangs(paths: list[str]) -> int:
-    # Cannot optimize on non-executability here if we intend this check to
-    # work on win32 -- and that's where problems caused by non-executability
-    # (elsewhere) are most likely to arise from.
-    return _check_git_filemode(paths)
+    fs_tracks_executable_bit = cmd_output(
+        'git', 'config', 'core.fileMode', retcode=None,
+    ).strip()
+    return (
+        _check_git_filemode(paths)
+        if fs_tracks_executable_bit == 'false'
+        else _check_fs_filemode(paths)
+    )
+
+
+def _check_fs_filemode(
+    paths: list[str],
+) -> int:  # pragma: win32 no cover
+    retv = 0
+    for path in paths:
+        if not os.access(path, os.X_OK) and has_shebang(path):
+            _message(path)
+            retv = 1
+
+    return retv
 
 
 def _check_git_filemode(paths: Sequence[str]) -> int:

tests/check_shebang_scripts_are_executable_test.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-import os
+import sys
 
 import pytest
 
@@ -9,6 +9,62 @@
 from pre_commit_hooks.check_shebang_scripts_are_executable import main
 from pre_commit_hooks.util import cmd_output
 
+skip_win32 = pytest.mark.xfail(
+    sys.platform == 'win32',
+    reason="non-git checks aren't relevant on windows",
+)
+
+
+@skip_win32  # pragma: win32 no cover
+@pytest.mark.parametrize(
+    'content', (
+        b'#!/bin/bash\nhello world\n',
+        b'#!/usr/bin/env python3.10',
+        b'#!python',
+        '#!☃'.encode(),
+    ),
+)
+def test_executable_shebang(content, tmpdir):
+    path = tmpdir.join('path')
+    path.write(content, 'wb')
+    cmd_output('chmod', '+x', path)
+    assert main((str(path),)) == 0
+
+
+@skip_win32  # pragma: win32 no cover
+@pytest.mark.parametrize(
+    'content', (
+        b'#!/bin/bash\nhello world\n',
+        b'#!/usr/bin/env python3.10',
+        b'#!python',
+        '#!☃'.encode(),
+    ),
+)
+def test_not_executable_shebang(content, tmpdir, capsys):
+    path = tmpdir.join('path')
+    path.write(content, 'wb')
+    assert main((str(path),)) == 1
+    _, stderr = capsys.readouterr()
+    assert stderr.startswith(
+        f'{path}: has a shebang but is not marked executable!',
+    )
+
+
+@skip_win32  # pragma: win32 no cover
+@pytest.mark.parametrize(
+    'content', (
+        b'',
+        b' #!python\n',
+        b'\n#!python\n',
+        b'python\n',
+        '☃'.encode(),
+    ),
+)
+def test_not_executable_no_shebang(content, tmpdir, capsys):
+    path = tmpdir.join('path')
+    path.write(content, 'wb')
+    assert main((str(path),)) == 0
+
 
 def test_check_git_filemode_passing(tmpdir):
     with tmpdir.as_cwd():
@@ -83,7 +139,5 @@ def test_git_executable_shebang(temp_git_dir, content, mode, expected):
         cmd_output('chmod', mode, str(path))
         cmd_output('git', 'update-index', f'--chmod={mode}', str(path))
 
-        # simulate how identify chooses that something is executable
-        filenames = [path for path in [str(path)] if os.access(path, os.X_OK)]
-
-        assert main(filenames) == expected
+        files = (str(path),)
+        assert main(files) == expected