Fix: Safe handling for multimodal_config to avoid 'NoneType' object h… (#227)

Signed-off-by: Baoyuan Qi <qibaoyuan@126.com>

vllm_omni/engine/arg_utils.py

@@ -52,7 +52,10 @@ class OmniEngineArgs(EngineArgs):
         # and adding the new omni-specific fields
         config_dict = base_config.__dict__.copy()
         # FIXME(Isotr0py): This is a temporary workaround for multimodal_config
-        config_dict = {**config_dict.pop("multimodal_config", {}).__dict__, **config_dict}
+        config_dict = {
+            **(getattr(mm := config_dict.pop("multimodal_config", None), "__dict__", mm or {})),
+            **config_dict,
+        }
 
         # Add the new omni-specific fields
         config_dict["stage_id"] = self.stage_id