refactor: reduce copied vLLM 0.29 compatibility code

Reuse upstream weight mapping and multimodal processing, consolidate Omni processor bridges, and trim unused Hunyuan internals. Route no-media kwargs through the active renderer and preserve GLM generation prompt formatting.

Validation: 453 CPU tests passed, 7 skipped; processor imports, Ruff, and diff checks passed. GPU and end-to-end CI not rerun.
Signed-off-by: tzhouam <tzhouam@connect.ust.hk>

tests/engine/test_async_omni_engine_stage_init.py

@@ -1593,73 +1593,42 @@ def test_model_path_resolver_is_generic_and_model_owned(tmp_path):
     assert "model_path_resolver" not in engine_args
 
 
-def test_build_stage0_input_processor_uses_omni_input_preprocessor(monkeypatch):
+def test_build_stage0_input_processor_wraps_active_renderer(monkeypatch):
     import vllm_omni.engine.stage_init_utils as init_mod
+    from vllm_omni.inputs.preprocess import OmniRenderer
+
+    original = object()
 
     class DummyInputProcessor:
         def __init__(self, vllm_config, renderer=None):
-            self.vllm_config = vllm_config
-            self.renderer = renderer or object()
-            self.input_preprocessor = None
-
-    class DummyOmniInputPreprocessor:
-        def __init__(self, vllm_config, renderer=None):
-            self.vllm_config = vllm_config
-            self.renderer = renderer
+            self.renderer = renderer or original
 
     monkeypatch.setattr(init_mod, "InputProcessor", DummyInputProcessor)
-    monkeypatch.setattr(init_mod, "OmniInputPreprocessor", DummyOmniInputPreprocessor)
-
-    input_processor = build_stage0_input_processor(
+    processor = build_stage0_input_processor(
         types.SimpleNamespace(model_config=types.SimpleNamespace(try_get_generation_config=lambda: {}))
     )
-
-    assert isinstance(input_processor.input_preprocessor, DummyOmniInputPreprocessor)
-    assert input_processor.input_preprocessor.renderer is input_processor.renderer
+    assert isinstance(processor.renderer, OmniRenderer)
+    assert processor.renderer._renderer is original
+    assert not hasattr(processor, "input_preprocessor")
 
 
-def test_build_stage0_input_processor_does_not_resolve_tokenizer_when_skipped(
-    monkeypatch,
-):
+def test_build_stage0_input_processor_does_not_resolve_tokenizer_when_skipped(monkeypatch):
     import vllm_omni.engine.stage_init_utils as init_mod
 
-    token_only_renderer = object()
-    seen = {}
+    original = object()
 
     class DummyInputProcessor:
         def __init__(self, vllm_config, renderer=None):
-            if renderer is None:
-                raise AssertionError("skip_tokenizer_init must supply a renderer")
-            seen["renderer"] = renderer
+            assert renderer is original
             self.renderer = renderer
-            self.input_preprocessor = None
-
-    class DummyOmniInputPreprocessor:
-        def __init__(self, vllm_config, renderer=None):
-            seen["preprocessor_renderer"] = renderer
 
     monkeypatch.setattr(init_mod, "InputProcessor", DummyInputProcessor)
-    monkeypatch.setattr(
-        init_mod,
-        "_build_token_only_renderer",
-        lambda _config: token_only_renderer,
-    )
-    monkeypatch.setattr(
-        init_mod,
-        "OmniInputPreprocessor",
-        DummyOmniInputPreprocessor,
-    )
-
+    monkeypatch.setattr(init_mod, "_build_token_only_renderer", lambda _: original)
     config = types.SimpleNamespace(
-        model_config=types.SimpleNamespace(
-            skip_tokenizer_init=True,
-            try_get_generation_config=lambda: {},
-        )
+        model_config=types.SimpleNamespace(skip_tokenizer_init=True, try_get_generation_config=lambda: {})
     )
-    build_stage0_input_processor(config)
-
-    assert seen["renderer"] is token_only_renderer
-    assert seen["preprocessor_renderer"] is token_only_renderer
+    processor = build_stage0_input_processor(config)
+    assert processor.renderer._renderer is original
 
 
 def test_inject_kv_stage_info_infers_sender_tp_topology():