[bugfix][CI] Diffusers backend update (#3096)

Signed-off-by: Huang, Zeyu <11222265+fhfuih@users.noreply.github.com>
Signed-off-by: Zeyu Huang | 黃澤宇 <11222265+fhfuih@users.noreply.github.com>
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

vllm_omni/diffusion/diffusion_engine.py

@@ -37,18 +37,23 @@ from vllm_omni.outputs import OmniRequestOutput
 logger = init_logger(__name__)
 
 
-def supports_image_input(model_class_name: str) -> bool:
-    model_cls = DiffusionModelRegistry._try_load_model_cls(model_class_name)
-    if model_cls is None:
-        return False
-    return bool(getattr(model_cls, "support_image_input", False))
+def supports_multimodal_input(od_config: OmniDiffusionConfig) -> tuple[bool, bool]:
+    if od_config.diffusion_load_format == "diffusers" and (pipe_cls := od_config.diffusers_pipeline_cls) is not None:
+        signature = inspect.signature(pipe_cls.__call__)
+        support_image_input = "image" in signature.parameters
+        support_audio_input = (
+            "audio" in signature.parameters or "audio_latents" in signature.parameters
+        )  # ref. LTX-2 format
+        return support_image_input, support_audio_input
 
+    supports_image_input = False
+    supports_audio_input = False
 
-def supports_audio_input(model_class_name: str) -> bool:
-    model_cls = DiffusionModelRegistry._try_load_model_cls(model_class_name)
-    if model_cls is None:
-        return False
-    return bool(getattr(model_cls, "support_audio_input", False))
+    model_cls = DiffusionModelRegistry._try_load_model_cls(od_config.model_class_name)
+    if model_cls is not None:
+        supports_image_input = bool(getattr(model_cls, "support_image_input", False))
+        supports_audio_input = bool(getattr(model_cls, "support_audio_input", False))
+    return supports_image_input, supports_audio_input
 
 
 def image_color_format(model_class_name: str) -> str:
@@ -416,23 +421,20 @@ class DiffusionEngine:
         num_inference_steps = 1
         height = 512
         width = 512
-        if supports_image_input(self.od_config.model_class_name):
+        prompt: OmniTextPrompt = {"prompt": "dummy run"}
+
+        supports_image_input, supports_audio_input = supports_multimodal_input(self.od_config)
+        if supports_image_input:
             # Provide a dummy image input if the model supports it
             color_format = image_color_format(self.od_config.model_class_name)
             dummy_image = PIL.Image.new(color_format, (width, height))
-        else:
-            dummy_image = None
+            prompt.setdefault("multi_modal_data", {})["image"] = dummy_image
 
-        if supports_audio_input(self.od_config.model_class_name):
+        if supports_audio_input:
             audio_sr = 16000
             dummy_audio = np.random.randn(audio_sr * 2).astype(np.float32)
-        else:
-            dummy_audio = None
+            prompt.setdefault("multi_modal_data", {})["audio"] = dummy_audio
 
-        prompt: OmniTextPrompt = {
-            "prompt": "dummy run",
-            "multi_modal_data": {"image": dummy_image, "audio": dummy_audio},
-        }
         req = OmniDiffusionRequest(
             prompts=[prompt],
             request_ids=["dummy_req_id"],