[BugFix] Fix NoneType' object has no attribute 'detach' (#2797)

Signed-off-by: amy-why-3459 <wuhaiyan17@huawei.com>

tests/e2e/online_serving/test_qwen3_omni.py

@@ -120,7 +120,7 @@ def test_mix_to_text_audio_001(omni_server, openai_client) -> None:
     }
 
     # Test single completion
-    openai_client.send_omni_request(request_config)
+    openai_client.send_omni_request(request_config, request_num=get_max_batch_size())
 
 
 @pytest.mark.advanced_model

vllm_omni/worker/gpu_ar_model_runner.py

@@ -797,12 +797,11 @@ class GPUARModelRunner(OmniGPUModelRunner, OmniConnectorModelRunnerMixin):
                     elif isinstance(v, dict):
                         mm_payload[k] = {sk: sv[start:end].contiguous() for sk, sv in v.items()}
                     elif isinstance(v, list):
-                        if idx < len(v):
-                            element = v[idx]
-                            if element is not None:
-                                if isinstance(element, torch.Tensor):
-                                    element = element.clone()
-                                mm_payload[k] = element
+                        element = v[idx] if idx < len(v) else v[0]
+                        if element is not None:
+                            if isinstance(element, torch.Tensor):
+                                element = element.clone()
+                            mm_payload[k] = element
                         # Skip None elements: msgspec cannot serialize None
                         # in dict[str, torch.Tensor] typed fields.
                     elif isinstance(v, torch.Tensor):