[Bugfix] Fix edge case in UUID data parsing (#34884)

Signed-off-by: DarkLight1337 <tlleungac@connect.ust.hk>

tests/renderers/test_process_multi_modal_uuids.py

@@ -42,6 +42,16 @@ def test_multi_modal_uuids_length_mismatch_raises():
 
     mm_data = {"image": [cherry_pil_image, stop_pil_image]}
 
+    # Mismatch: 2 items but only 0 uuids provided
+    mm_uuids = {"image": []}  # type: ignore[var-annotated]
+
+    mm_processor = renderer.get_mm_processor()
+    mm_data_items = mm_processor.info.parse_mm_data(mm_data)
+    mm_uuid_items = parse_mm_uuids(mm_uuids)
+
+    with pytest.raises(ValueError, match="must have same length as"):
+        renderer._process_mm_uuids(mm_data, mm_data_items, mm_uuid_items, "req-1a")
+
     # Mismatch: 2 items but only 1 uuid provided
     mm_uuids = {"image": ["hash_cherry"]}
 
@@ -50,7 +60,7 @@ def test_multi_modal_uuids_length_mismatch_raises():
     mm_uuid_items = parse_mm_uuids(mm_uuids)
 
     with pytest.raises(ValueError, match="must have same length as"):
-        renderer._process_mm_uuids(mm_data, mm_data_items, mm_uuid_items, "req-1")
+        renderer._process_mm_uuids(mm_data, mm_data_items, mm_uuid_items, "req-1b")
 
 
 def test_multi_modal_uuids_missing_modality_raises():
@@ -125,8 +135,8 @@ def test_multi_modal_uuids_accepts_empty(
 
     # While None means cached multi-modal input requiring UUIDs
     # an empty list means no multi-modal input
-    mm_data = {"image": [], "video": []}  # type: ignore[var-annotated]
-    mm_uuids = {"image": [], "video": None}  # type: ignore[var-annotated]
+    mm_data = {"image": [], "video": [], "audio": None}  # type: ignore[var-annotated]
+    mm_uuids = {"image": [], "video": None, "audio": []}  # type: ignore[var-annotated]
 
     mm_processor = renderer.get_mm_processor()
     mm_data_items = mm_processor.info.parse_mm_data(mm_data)

vllm/renderers/base.py

@@ -482,7 +482,7 @@ class BaseRenderer(ABC, Generic[_T]):
                     )
 
             elif uuid_items is not None:
-                if len(uuid_items) > 0 and len(data_items) != len(uuid_items):
+                if len(data_items) != len(uuid_items):
                     raise ValueError(
                         f"If given, multi_modal_uuids[{modality!r}] must have "
                         f"same length as multi_modal_data[{modality!r}], but "