[Model] Add native MAGI-2 Preview diffusion support (#5918)

Signed-off-by: Hongsheng Liu <liuhongsheng4@huawei.com>
Signed-off-by: hsliuustc0106 <liuhongsheng4@huawei.com>

vllm_omni/diffusion/data.py

@@ -631,10 +631,14 @@ def resolve_model_class_name(
     """
     from vllm.transformers_utils.config import get_hf_file_to_dict
 
-    from vllm_omni.diffusion.utils.hf_utils import get_diffusion_model_index
+    from vllm_omni.diffusion.utils.hf_utils import get_diffusion_model_index, resolve_native_diffusion_model_class
 
     if not model:
         return None
+    native_model_class = resolve_native_diffusion_model_class(model)
+    if native_model_class is not None:
+        return native_model_class
+
     is_lance_subfolder = os.path.basename(str(model).rstrip("/")) in {"Lance_3B", "Lance_3B_Video"}
 
     # Diffusers models: read _class_name from the pipeline index. Missing
@@ -1332,7 +1336,10 @@ class OmniDiffusionConfig:
         """
         from vllm.transformers_utils.config import get_hf_file_to_dict
 
-        from vllm_omni.diffusion.utils.hf_utils import get_diffusion_model_index
+        from vllm_omni.diffusion.utils.hf_utils import (
+            get_diffusion_model_index,
+            resolve_native_diffusion_model_class,
+        )
 
         assert self.model is not None
         try:
@@ -1398,6 +1405,12 @@ class OmniDiffusionConfig:
             else:
                 cfg = get_hf_file_to_dict("config.json", self.model, revision=self.revision)
                 if cfg is None:
+                    native_model_class = resolve_native_diffusion_model_class(self.model)
+                    if native_model_class is not None:
+                        self.model_class_name = native_model_class
+                        self.set_tf_model_config(TransformerConfig())
+                        self.update_multimodal_support()
+                        return
                     # Lance ships its top-level config.json one directory above
                     # the per-checkpoint subfolders (``Lance_3B/`` or
                     # ``Lance_3B_Video/``).  Try to recover that case before