[diffusion] fix: fix missing backend argument in pipelines_core initialization (#17343)

python/sglang/multimodal_gen/configs/pipeline_configs/base.py

@@ -547,7 +547,7 @@ class PipelineConfig:
                     f"using {pipeline_config_cls.__name__} directly without model_index.json"
                 )
             else:
-                model_info = get_model_info(model_path)
+                model_info = get_model_info(model_path, backend=kwargs.get("backend"))
                 if model_info is None:
                     from sglang.multimodal_gen.registry import (
                         _PIPELINE_CONFIG_REGISTRY,
@@ -563,7 +563,7 @@ class PipelineConfig:
                     )
                 pipeline_config_cls = model_info.pipeline_config_cls
         else:
-            model_info = get_model_info(model_path)
+            model_info = get_model_info(model_path, backend=kwargs.get("backend"))
             if model_info is None:
                 raise ValueError(
                     f"Could not get model info for '{model_path}'. "

python/sglang/multimodal_gen/configs/sample/sampling_params.py

@@ -417,14 +417,17 @@ class SamplingParams:
     def from_pretrained(cls, model_path: str, **kwargs) -> "SamplingParams":
         from sglang.multimodal_gen.registry import get_model_info
 
-        model_info = get_model_info(model_path)
+        backend = kwargs.pop("backend", None)
+        model_info = get_model_info(model_path, backend=backend)
         sampling_params: SamplingParams = model_info.sampling_param_cls(**kwargs)
         return sampling_params
 
     @staticmethod
     def from_user_sampling_params_args(model_path: str, server_args, *args, **kwargs):
         try:
-            sampling_params = SamplingParams.from_pretrained(model_path)
+            sampling_params = SamplingParams.from_pretrained(
+                model_path, backend=server_args.backend
+            )
         except (AttributeError, ValueError) as e:
             # Handle safetensors files or other cases where model_index.json is not available
             # Use appropriate SamplingParams based on pipeline_class_name from registry

python/sglang/multimodal_gen/runtime/entrypoints/openai/common_api.py

@@ -180,7 +180,7 @@ async def available_models():
     if not server_args:
         raise HTTPException(status_code=500, detail="Server args not initialized")
 
-    model_info = get_model_info(server_args.model_path)
+    model_info = get_model_info(server_args.model_path, backend=server_args.backend)
 
     card_kwargs = {
         "id": server_args.model_path,
@@ -222,7 +222,7 @@ async def retrieve_model(model: str):
             },
         )
 
-    model_info = get_model_info(server_args.model_path)
+    model_info = get_model_info(server_args.model_path, backend=server_args.backend)
 
     card_kwargs = {
         "id": model,

python/sglang/multimodal_gen/runtime/pipelines_core/__init__.py

@@ -66,7 +66,7 @@ def build_pipeline(
         )
     else:
         logger.info("No pipeline_class_name specified, using model_index.json")
-        model_info = get_model_info(model_path)
+        model_info = get_model_info(model_path, backend=server_args.backend)
         pipeline_cls = model_info.pipeline_cls
         logger.info(f"Using pipeline from model_index.json: {pipeline_cls.__name__}")