Fix scandir() crash by returning [] when directory is not found (#13083)

AUTHORS

@@ -360,6 +360,7 @@ Ran Benita
 Raphael Castaneda
 Raphael Pierzina
 Rafal Semik
+Reza Mousavi
 Raquel Alegre
 Ravi Chandra
 Reagan Lee

changelog/13083.bugfix.rst

@@ -0,0 +1,6 @@
+13083.bugfix.rst:
+
+Fix issue where the `scandir` function in `pathlib.py` caused symlink loops under certain conditions.
+
+- Issue: https://github.com/pytest-dev/pytest/issues/13083
+- Authors: Reza Mousavi

src/_pytest/pathlib.py

@@ -955,21 +955,25 @@ def scandir(
 
     The returned entries are sorted according to the given key.
     The default is to sort by name.
+    If the directory does not exist, return an empty list.
     """
-    entries = []
-    with os.scandir(path) as s:
-        # Skip entries with symlink loops and other brokenness, so the caller
-        # doesn't have to deal with it.
-        for entry in s:
-            try:
-                entry.is_file()
-            except OSError as err:
-                if _ignore_error(err):
-                    continue
-                raise
-            entries.append(entry)
-    entries.sort(key=sort_key)  # type: ignore[arg-type]
-    return entries
+    try:
+        entries = []
+        with os.scandir(path) as s:
+            # Skip entries with symlink loops and other brokenness, so the caller
+            # doesn't have to deal with it.
+            for entry in s:
+                try:
+                    entry.is_file()
+                except OSError as err:
+                    if _ignore_error(err):
+                        continue
+                    raise
+                entries.append(entry)
+        entries.sort(key=sort_key)  # type: ignore[arg-type]
+        return entries
+    except FileNotFoundError:
+        return []
 
 
 def visit(

testing/test_pathlib.py

@@ -38,6 +38,7 @@
 from _pytest.pathlib import resolve_package_path
 from _pytest.pathlib import resolve_pkg_root_and_module_name
 from _pytest.pathlib import safe_exists
+from _pytest.pathlib import scandir
 from _pytest.pathlib import spec_matches_module_path
 from _pytest.pathlib import symlink_or_skip
 from _pytest.pathlib import visit
@@ -569,6 +570,29 @@ def test_samefile_false_negatives(tmp_path: Path, monkeypatch: MonkeyPatch) -> N
     assert getattr(module, "foo")() == 42
 
 
+def test_scandir_with_non_existent_directory() -> None:
+    # Test with a directory that does not exist
+    non_existent_dir = "path_to_non_existent_dir"
+    result = scandir(non_existent_dir)
+    # Assert that the result is an empty list
+    assert result == []
+
+
+def test_scandir_handles_os_error():
+    # Create a mock entry that will raise an OSError when is_file is called
+    mock_entry = unittest.mock.MagicMock()
+    mock_entry.is_file.side_effect = OSError("Permission denied")
+    # Mock os.scandir to return an iterator with our mock entry
+    with unittest.mock.patch("os.scandir") as mock_scandir:
+        mock_scandir.return_value.__enter__.return_value = [mock_entry]
+        # Call the scandir function with a path
+        # We expect an OSError to be raised here
+        with pytest.raises(OSError, match="Permission denied"):
+            scandir("/fake/path")
+        # Verify that the is_file method was called on the mock entry
+        mock_entry.is_file.assert_called_once()
+
+
 class TestImportLibMode:
     def test_importmode_importlib_with_dataclass(
         self, tmp_path: Path, ns_param: bool