Fix test_dir_without_exec_permission on Python 3.14

One unit test fails on Python 3.14 as follows:

```
_____________ TestFolderTraversal.test_dir_without_exec_permission _____________

self = <test.unit.scan.test_folder_traversal.TestFolderTraversal object at 0x7f5530606350>
tmp_path = PosixPath('/tmp/pytest-of-sbuild/pytest-0/test_dir_without_exec_permissi0')
fs_perm_tool = <test.unit.conftest.UnixPermTool object at 0x7f55301ca510>

    @pytest.mark.skipif(
        platform.system() == 'Windows',
        reason='Unix-only filesystem permissions are tested',
    )
    def test_dir_without_exec_permission(self, tmp_path, fs_perm_tool):
        """Test that a excluded directory/file without permissions emits warnings."""
        no_perm_dir = tmp_path / 'no_perm_dir'
        no_perm_dir.mkdir()
        (no_perm_dir / 'file.txt').touch()
        (no_perm_dir / 'file2.txt').touch()
        # chmod -x no_perm_dir
        no_perm_dir.chmod(0o600)

        scan_policy = ScanPoliciesManager()
        reporter = ProgressReport(sys.stdout, False)

        folder = LocalFolder(str(tmp_path))
        local_paths = folder.all_files(reporter=reporter, policies_manager=scan_policy)
        absolute_paths = [path.absolute_path for path in local_paths]
        assert not absolute_paths

        # Check that no access warnings are issued for the excluded directory/file
>       assert set(reporter.warnings) == {
            f'WARNING: {tmp_path/"no_perm_dir/file.txt"} could not be accessed (no permissions to read?)',
            f'WARNING: {tmp_path/"no_perm_dir/file2.txt"} could not be accessed (no permissions to read?)',
        }
E       AssertionError: assert {'WARNING: /t...en symlink?)'} == {'WARNING: /t...ns to read?)'}
E
E         Extra items in the left set:
E         'WARNING: /tmp/pytest-of-sbuild/pytest-0/test_dir_without_exec_permissi0/no_perm_dir/file2.txt could not be accessed (broken symlink?)'
E         'WARNING: /tmp/pytest-of-sbuild/pytest-0/test_dir_without_exec_permissi0/no_perm_dir/file.txt could not be accessed (broken symlink?)'
E         Extra items in the right set:
E         'WARNING: /tmp/pytest-of-sbuild/pytest-0/test_dir_without_exec_permissi0/no_perm_dir/file.txt could not be accessed (no permissions to read?)'
E         'WARNING: /tmp/pytest-of-sbuild/pytest-0/test_dir_without_exec_permissi0/no_perm_dir/file2.txt could not be accessed (no permissions to read?)'
E         Use -v to get more diff

test/unit/scan/test_folder_traversal.py:721: AssertionError
```

This is due to python/cpython#118243.  I'm not
sure how important it is to preserve the exact same warning message
here, but the conservative approach is to do so;
https://docs.python.org/3/library/pathlib.html advises using `Path.stat`
to distinguish these cases.

Author: cjwatson

b2sdk/_internal/scan/folder.py

@@ -13,6 +13,7 @@
 import os
 import platform
 import re
+import stat
 import sys
 from abc import ABCMeta, abstractmethod
 from pathlib import Path
@@ -274,14 +275,19 @@ def _walk_relative_paths(
                     reporter.invalid_name(str(local_path), str(e))
                 continue
 
+            # Deliberately don't use Path.is_dir here: for directories
+            # without search permission, Python 3.13 raises PermissionError
+            # while Python 3.14 returns False.
             try:
-                is_dir = local_path.is_dir()
+                is_dir = stat.S_ISDIR(local_path.stat().st_mode)
             except PermissionError:  # `chmod -x dir` can trigger this
                 if reporter is not None and not policies_manager.should_exclude_local_directory(
                     str(relative_file_path)
                 ):
                     reporter.local_permission_error(str(local_path))
                 continue
+            except (OSError, ValueError):
+                is_dir = False
 
             if is_dir:
                 if policies_manager.should_exclude_local_directory(str(relative_file_path)):

changelog.d/+py314-test.fixed.md

@@ -0,0 +1 @@
+Fix `TestFolderTraversal.test_dir_without_exec_permission` on Python 3.14.