Bug fix / workaround in lib/spack/spack/llnl/util/filesystem.py: prevent recursively traversing the root filesystem (#576)

Author: climbfuji

lib/spack/spack/llnl/util/filesystem.py

@@ -1812,6 +1812,15 @@ def _dedupe_files(paths: List[str]) -> List[str]:
     return unique_files
 
 
+def _is_root_directory(curr_dir: str):
+    """
+    Check if the given directory is the top-level root directory.
+    Works on Windows, macOS, and Linux.
+    """
+    path = pathlib.Path(curr_dir).resolve()
+    return path == path.anchor or path.parent == path
+
+
 def _find_max_depth(
     roots: Sequence[Path], globs: Sequence[str], max_depth: int = sys.maxsize
 ) -> List[str]:
@@ -1846,6 +1855,9 @@ def _find_max_depth(
 
     while dir_queue:
         depth, curr_dir = dir_queue.pop()
+        # Never traverse root recursively
+        if _is_root_directory(curr_dir):
+            continue
         try:
             dir_iter = os.scandir(curr_dir)
         except OSError as e: