[misc] fix: Allow HF model ID with use_shm

verl/utils/fs.py

@@ -198,7 +198,7 @@ def copy_to_local(
     """Copy files/directories from HDFS to local cache with validation.
 
     Args:
-        src (str): Source path - HDFS path (hdfs://...) or local filesystem path
+        src (str): Source path - HDFS path (hdfs://...), local filesystem path, or Hugging Face model ID
         cache_dir (str, optional): Local directory for cached files. Uses system tempdir if None
         filelock (str): Base name for file lock. Defaults to ".file.lock"
         verbose (bool): Enable copy operation logging. Defaults to False
@@ -210,6 +210,19 @@ def copy_to_local(
     """
     # Save to a local path for persistence.
     local_path = copy_local_path_from_hdfs(src, cache_dir, filelock, verbose, always_recopy)
+
+    if use_shm and isinstance(local_path, str) and not os.path.exists(local_path):
+        try:
+            from huggingface_hub import snapshot_download
+
+            resolved = snapshot_download(local_path)
+            if isinstance(resolved, str) and os.path.exists(resolved):
+                local_path = resolved
+        except ImportError:
+            pass
+        except Exception as e:
+            print(f"WARNING: Failed to download model from Hugging Face: {e}")
+
     # Load into shm to improve efficiency.
     if use_shm:
         return copy_to_shm(local_path)