Path.chmod() silently fails on Windows when archive bit is cleared and follow_symlinks=True

[kmray]

Bug report

Bug description:

Expected behavior:

• Path.chmod(stat.S_IWRITE | stat.S_IREAD) should clear the read-only attribute regardless of archive bit state
• Path.chmod(stat.S_IWRITE | stat.S_IREAD) should match os.chmod() behavior

Actual behavior:

• When archive bit is cleared, Path.chmod(stat.S_IWRITE | stat.S_IREAD) silently fails to clear read-only
• When archive bit is set, it works correctly
• Path.chmod(stat.S_IWRITE | stat.S_IREAD, follow_symlinks=False) always works

import os
import stat
import subprocess
from pathlib import Path


def is_read_only(file: str | os.PathLike) -> bool:
    return os.stat(file).st_file_attributes & stat.FILE_ATTRIBUTE_READONLY > 0


test_file = Path('test.txt')
test_file.touch()

subprocess.run(f'attrib -a +r {test_file}', check=True)
print(f'Initial (no archive): Read Only: {is_read_only(test_file)}')

test_file.chmod(stat.S_IWRITE | stat.S_IREAD)
print(f'After chmod(follow_symlinks=True): Read Only: {is_read_only(test_file)}')

test_file.chmod(stat.S_IWRITE | stat.S_IREAD, follow_symlinks=False)
print(f'After chmod(follow_symlinks=False): {is_read_only(test_file)}')

subprocess.run(f'attrib +a +r {test_file}', check=True)
print(f'Initial (archive): Read Only: {is_read_only(test_file)}')

test_file.chmod(stat.S_IWRITE | stat.S_IREAD)
print(f'After chmod(follow_symlinks=True): Read Only: {is_read_only(test_file)}')

test_file.chmod(stat.S_IWRITE | stat.S_IREAD, follow_symlinks=False)
print(f'After chmod(follow_symlinks=False): {is_read_only(test_file)}')

Output

Initial (no archive): Read Only: True
After chmod(follow_symlinks=True): Read Only: True
After chmod(follow_symlinks=False): False
Initial (archive): Read Only: True
After chmod(follow_symlinks=True): Read Only: False
After chmod(follow_symlinks=False): False

CPython versions tested on:

3.14

Operating systems tested on:

Windows

Linked PRs

• gh-140774: Fix pathlib.Path.chmod handling of Windows Archive bit #142018