[diffusion] feat: Add --model-id for config resolution; deprecate model_detectors (#19607)

python/sglang/multimodal_gen/registry.py

@@ -245,10 +245,29 @@ def get_model_short_name(model_id: str) -> str:
         return model_id
 
 
-def _get_config_info(model_path: str) -> Optional[ConfigInfo]:
+@lru_cache(maxsize=1)
+def _get_config_info(
+    model_path: str, model_id: Optional[str] = None
+) -> Optional[ConfigInfo]:
     """
     Gets the ConfigInfo for a given model path using mappings and detectors.
     """
+    all_model_hf_paths = sorted(_MODEL_HF_PATH_TO_NAME.keys(), key=len, reverse=True)
+
+    # 0. Explicit model_id override: match by short name
+    if model_id is not None:
+        model_id_lower = model_id.lower()
+        for registered_hf_id in all_model_hf_paths:
+            if get_model_short_name(registered_hf_id).lower() == model_id_lower:
+                logger.debug(
+                    f"Resolved model via explicit --model-id '{model_id}' → '{registered_hf_id}'."
+                )
+                return _CONFIG_REGISTRY.get(_MODEL_HF_PATH_TO_NAME[registered_hf_id])
+        logger.warning(
+            f"--model-id '{model_id}' did not match any registered model; "
+            "falling back to automatic detection."
+        )
+
     # 1. Exact match
     if model_path in _MODEL_HF_PATH_TO_NAME:
         model_id = _MODEL_HF_PATH_TO_NAME[model_path]
@@ -256,12 +275,11 @@ def _get_config_info(model_path: str) -> Optional[ConfigInfo]:
         return _CONFIG_REGISTRY.get(model_id)
 
     # 2. Partial match: find the best (longest) match against all registered model hf paths.
-    model_name = get_model_short_name(model_path.lower())
-    all_model_hf_paths = sorted(_MODEL_HF_PATH_TO_NAME.keys(), key=len, reverse=True)
+    model_short_name = get_model_short_name(model_path.lower())
     for registered_model_hf_id in all_model_hf_paths:
         registered_model_name = get_model_short_name(registered_model_hf_id.lower())
 
-        if registered_model_name == model_name:
+        if registered_model_name == model_short_name:
             logger.debug(
                 f"Resolved model name '{registered_model_hf_id}' from partial path match."
             )
@@ -310,7 +328,7 @@ class ModelInfo:
     pipeline_config_cls: Type[PipelineConfig]
 
 
-def _get_diffusers_model_info(model_path: str) -> ModelInfo:
+def _get_diffusers_model_info() -> ModelInfo:
     """
     Get model info for diffusers backend.
 
@@ -337,6 +355,7 @@ def _get_diffusers_model_info(model_path: str) -> ModelInfo:
 def get_model_info(
     model_path: str,
     backend: Optional[Union[str, "Backend"]] = None,
+    model_id: Optional[str] = None,
 ) -> Optional[ModelInfo]:
     """
     Resolves all necessary classes (pipeline, sampling, config) for a given model path.
@@ -365,7 +384,7 @@ def get_model_info(
         logger.info(
             "Using diffusers backend for model '%s' (explicitly requested)", model_path
         )
-        return _get_diffusers_model_info(model_path)
+        return _get_diffusers_model_info()
 
     # For AUTO or SGLANG backend, try native implementation first
     # 1. Discover all available pipeline classes and cache them
@@ -389,7 +408,7 @@ def get_model_info(
             logger.error(f"Could not read model config for '{model_path}': {e}")
             if backend == Backend.AUTO:
                 logger.info("Falling back to diffusers backend")
-                return _get_diffusers_model_info(model_path)
+                return _get_diffusers_model_info()
             return None
 
         pipeline_class_name = config.get("_class_name")
@@ -399,7 +418,7 @@ def get_model_info(
             )
             if backend == Backend.AUTO:
                 logger.info("Falling back to diffusers backend")
-                return _get_diffusers_model_info(model_path)
+                return _get_diffusers_model_info()
             return None
 
     pipeline_cls = _PIPELINE_REGISTRY.get(pipeline_class_name)
@@ -409,7 +428,7 @@ def get_model_info(
                 f"Pipeline class '{pipeline_class_name}' specified in '{model_path}' has no native sglang support. "
                 f"Falling back to diffusers backend."
             )
-            return _get_diffusers_model_info(model_path)
+            return _get_diffusers_model_info()
         else:
             logger.error(
                 f"Pipeline class '{pipeline_class_name}' specified in '{model_path}' is not a registered EntryClass in the framework. "
@@ -419,14 +438,14 @@ def get_model_info(
             return None
 
     # 3. Get configuration classes (sampling, pipeline config)
-    config_info = _get_config_info(model_path)
+    config_info = _get_config_info(model_path, model_id=model_id)
     if not config_info:
         if backend == Backend.AUTO:
             logger.warning(
                 f"Could not resolve native configuration for model '{model_path}'. "
                 f"Falling back to diffusers backend."
             )
-            return _get_diffusers_model_info(model_path)
+            return _get_diffusers_model_info()
         else:
             logger.error(
                 f"Could not resolve configuration for model '{model_path}'. "