Raise explicit error on directory traversal cycles when recursively loading directory files

src/pytest_data_loader/loaders/impl.py

@@ -518,6 +518,14 @@ def load(self) -> Iterable[LoadedData | LazyLoadedData]:  # type: ignore[overrid
         """Load multiple files from a directory"""
 
         def load_files(dir_path: Path) -> None:
+            if self.load_attrs.recursive:
+                # Detect directory traversal cycles by tracking visited inodes
+                stat = dir_path.stat()
+                inode = (stat.st_dev, stat.st_ino)
+                if inode in visited_dirs:
+                    raise RuntimeError(f"Detected a circular symlink: {dir_path}")
+                visited_dirs.add(inode)
+
             for p in sorted(dir_path.iterdir()):
                 if p.is_dir():
                     if self.load_attrs.recursive:
@@ -546,6 +554,7 @@ def load_files(dir_path: Path) -> None:
                         assert isinstance(loaded_data, LoadedData | LazyLoadedData), type(loaded_data)
                         loaded_files.append(loaded_data)
 
+        visited_dirs: set[tuple[int, int]] = set()
         loaded_files: list[LoadedData | LazyLoadedData] = []
         load_files(self.path)
         return loaded_files

src/pytest_data_loader/utils.py

@@ -178,7 +178,7 @@ def validate_loader_func_args_and_normalize(
 
 
 def check_circular_symlink(path: Path) -> None:
-    """Detect a circular symlink
+    """Detect a circular symlink resolution loops (ELOOP)
 
     :param path: The path to check
     """

tests/data/symlinks/dir/symlink

@@ -0,0 +1 @@
+../../dir

tests/tests_plugin/helper.py

@@ -174,6 +174,7 @@ def run_pytest_with_context(
     read_option_func_def: str | None = None,
     collect_only: bool = False,
     check_test_id: bool = False,
+    **other_loader_options: Any,
 ) -> RunResult:
     """Common test logic that runs pytest via pytester with various test context and checks the basic functionality
     of pytest-data-loader plugin
@@ -206,6 +207,8 @@ def run_pytest_with_context(
         loader_options.append(f"{DataLoaderFunctionType.FILE_READER_FUNC}={file_reader_func_def}")
     if read_option_func_def:
         loader_options.append(f"{DataLoaderFunctionType.READ_OPTION_FUNC}={read_option_func_def}")
+    if other_loader_options:
+        loader_options.extend(f"{k}={v!r}" for k, v in other_loader_options.items())
     loader_options_str = ", " + ", ".join(loader_options) if loader_options else ""
 
     is_abs_path = Path(test_context.path).is_absolute()

tests/tests_plugin/test_data_path.py

@@ -92,28 +92,27 @@ def test_parametrize_dir_loader_with_no_file(test_context: TestContext, loader:
 @pytest.mark.parametrize("is_abs_path", [False, True])
 @pytest.mark.parametrize("is_circular", [False, True])
 def test_symlink(test_context: TestContext, is_circular: bool, is_abs_path: bool, collect_only: bool) -> None:
-    """Test that symlinks are handled properly, including circular symlinks"""
-    symlink_data_dir_name = "symlinks"
-    src_symlink_data_dir = ABS_PATH_LOADER_DIR / symlink_data_dir_name
-    dst = Path(test_context.data_dir) / symlink_data_dir_name
-    if is_circular:
-        src_symlink_data_dir /= "circular"
-        dst.mkdir(exist_ok=True, parents=True)
-        dst /= "circular"
-
+    """Test that symlinks are handled properly, including circular symlinks (ELOOP and directory traversal cycles)"""
+    src_symlink_data_dir = ABS_PATH_LOADER_DIR / "symlinks"
+    dst = Path(test_context.data_dir) / src_symlink_data_dir.name
     dst.symlink_to(src_symlink_data_dir, target_is_directory=True)
 
+    kwargs = {}
     if test_context.loader.is_file_loader:
-        dir_or_filename = "symlink.txt"
+        dir_or_file = Path("symlink.txt")
     else:
-        dir_or_filename = "symlink"
+        dir_or_file = Path("dir", "symlink")
+        kwargs.update(recursive=True)
+
+    if is_circular:
+        dir_or_file = Path("circular", dir_or_file)
 
     if is_abs_path:
-        path = dst / dir_or_filename
+        path = dst / dir_or_file
     else:
-        path = dst.relative_to(test_context.data_dir) / dir_or_filename
+        path = dst.relative_to(test_context.data_dir) / dir_or_file
 
-    result = run_pytest_with_context(test_context, path=path, collect_only=collect_only)
+    result = run_pytest_with_context(test_context, path=path, collect_only=collect_only, **kwargs)
     if is_circular:
         assert result.ret == ExitCode.INTERRUPTED
         assert "Detected a circular symlink" in str(result.stdout)