[diffusion] chore: fetch metadata beside nested lora weights (#36057)

python/sglang/multimodal_gen/runtime/utils/hf_diffusers_utils.py

@@ -663,12 +663,16 @@ def maybe_download_lora(
         return os.path.join(source.local_path, selected_file)
 
     assert source.repo_id is not None
+    allow_patterns = ["*.json", selected_file]
+    selected_parent = os.path.dirname(selected_file)
+    if selected_parent:
+        allow_patterns.insert(1, f"{selected_parent}/*.json")
     local_path = maybe_download_model(
         source.repo_id,
         local_dir,
         download,
         is_lora=True,
-        allow_patterns=["*.json", selected_file],
+        allow_patterns=allow_patterns,
         revision=resolved_weight.inventory.resolved_revision or source.revision,
     )
     target = os.path.join(local_path, selected_file)

python/sglang/multimodal_gen/test/unit/test_lora_pipeline.py

@@ -176,6 +176,7 @@ def test_lora_tree_url_selects_one_pinned_weight(tmp_path):
     assert download.call_args.kwargs["revision"] == "immutable-sha"
     assert download.call_args.kwargs["allow_patterns"] == [
         "*.json",
+        "adapters/*.json",
         f"adapters/{weight_name}",
     ]