[BugFix] Probe __dict__ instead of hasattr when patching WanRMS_norm (#3400)

Signed-off-by: gcanlin <canlinguosdu@gmail.com>

vllm_omni/diffusion/models/wan2_2/patch_diffusers.py

@@ -9,10 +9,11 @@ from vllm_omni.diffusion.layers.norm import RMSNormVAE
 def patch_wan_rms_norm():
     """Patch diffusers Wan RMSNorm implementation with RMSNormVAE."""
 
-    # NOTE: iterate over a snapshot of sys.modules. `hasattr` can trigger lazy
-    # submodule imports (e.g. transformers' `_LazyModule.__getattr__`), which
-    # mutate sys.modules during iteration and raise
-    # `RuntimeError: dictionary changed size during iteration`.
-    for module_name, module in list(sys.modules.items()):
-        if hasattr(module, "WanRMS_norm"):
-            setattr(module, "WanRMS_norm", RMSNormVAE)
+    # Probe `__dict__` directly instead of `hasattr`: the latter triggers
+    # custom `__getattr__` hooks (e.g. transformers' image_processing alias
+    # modules), which both emit spurious deprecation warnings and can lazily
+    # import submodules, mutating sys.modules mid-iteration.
+    for module in list(sys.modules.values()):
+        module_dict = getattr(module, "__dict__", None)
+        if module_dict is not None and "WanRMS_norm" in module_dict:
+            module_dict["WanRMS_norm"] = RMSNormVAE