Fix cleanup of empty directories under read-only parents

changelog/15341.bugfix.rst

@@ -0,0 +1 @@
+Temporary directory cleanup now removes empty directories beneath read-only parents instead of leaving the session's temporary files behind.

src/_pytest/pathlib.py

@@ -158,9 +158,9 @@ def on_rm_rf_error(
         return False
 
     # Chmod + retry.
-    # For files, we need to recursively go upwards in the directories to
-    # ensure they all are also accessible and writable.
-    if p.is_file():
+    # Removing a file or an empty directory requires write access to its
+    # parent, which may also be inaccessible through its own parents.
+    if p.is_file() or func is os.rmdir:
         for parent in p.parents:  # pragma: no branch
             _chmod_rwx(str(parent))
             # Stop when we reach the original path passed to rm_rf.

testing/test_tmpdir.py

@@ -877,6 +877,40 @@ def test_on_rm_rf_error_chmod_retry_walks_parents(self, tmp_path: Path) -> None:
         on_rm_rf_error(os.unlink, str(fn), exc_info, start_path=tmp_path)
         assert not fn.exists()
 
+    @pytest.mark.skipif(not hasattr(os, "getuid"), reason="unix permissions")
+    def test_rm_rf_empty_dir_under_read_only_parent(self, tmp_path: Path) -> None:
+        root = tmp_path / "root"
+        parent = root / "parent"
+        empty = parent / "empty"
+        empty.mkdir(parents=True)
+        parent.chmod(0o500)
+
+        try:
+            rm_rf(root)
+            assert not root.exists()
+        finally:
+            if parent.exists():
+                parent.chmod(0o700)
+
+    def test_on_rm_rf_error_chmods_empty_dir_parents(
+        self, tmp_path: Path, monkeypatch: MonkeyPatch
+    ) -> None:
+        parent = tmp_path / "parent"
+        empty = parent / "empty"
+        empty.mkdir(parents=True)
+        chmod_paths: list[str] = []
+
+        def record_chmod(path: str) -> bool:
+            chmod_paths.append(path)
+            return _chmod_rwx(path)
+
+        monkeypatch.setattr(pathlib, "_chmod_rwx", record_chmod)
+        assert on_rm_rf_error(
+            os.rmdir, str(empty), PermissionError(), start_path=tmp_path
+        )
+        assert str(parent) in chmod_paths
+        assert not empty.exists()
+
 
 def attempt_symlink_to(path, to_path):
     """Try to make a symlink from "path" to "to_path", skipping in case this platform