Speed up mm processor kwargs per request by spliting dynamic and static kwargs (#26483)

Signed-off-by: Junhong <liujunhong11@huawei.com>
Signed-off-by: Junhong Liu <98734602+LJH-LBJ@users.noreply.github.com>
Co-authored-by: Junhong <liujunhong11@huawei.com>

tests/transformers_utils/test_get_processor_kwargs_from_processor.py

@@ -0,0 +1,66 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+import importlib
+
+from transformers.processing_utils import ProcessingKwargs
+from typing_extensions import Unpack
+
+from vllm.transformers_utils.processor import (
+    get_processor_kwargs_from_processor,
+)
+
+
+class _FakeProcessorKwargs(ProcessingKwargs, total=False):  # type: ignore
+    pass
+
+
+def _assert_has_all_expected(keys: set[str]) -> None:
+    # text
+    for k in ("text_pair", "text_target", "text_pair_target"):
+        assert k in keys
+    # image
+    for k in ("do_convert_rgb", "do_resize"):
+        assert k in keys
+    # audio
+    for k in (
+        "fps",
+        "do_sample_frames",
+        "input_data_format",
+        "default_to_square",
+    ):
+        assert k in keys
+    # audio
+    for k in ("padding", "return_attention_mask"):
+        assert k in keys
+
+
+# Path 1: __call__ method has kwargs: Unpack[*ProcessingKwargs]
+class _ProcWithUnpack:
+    def __call__(self, *args, **kwargs: Unpack[_FakeProcessorKwargs]):  # type: ignore
+        return None
+
+
+def test_get_processor_kwargs_from_processor_unpack_path_returns_full_union():
+    proc = _ProcWithUnpack()
+    keys = get_processor_kwargs_from_processor(proc)
+    _assert_has_all_expected(keys)
+
+
+# ---- Path 2: No Unpack, fallback to scanning *ProcessingKwargs in module ----
+
+
+class _ProcWithoutUnpack:
+    def __call__(self, *args, **kwargs):
+        return None
+
+
+def test_get_processor_kwargs_from_processor_module_scan_returns_full_union():
+    # ensure the module scanned by fallback is this test module
+    module_name = _ProcWithoutUnpack.__module__
+    mod = importlib.import_module(module_name)
+    assert hasattr(mod, "_FakeProcessorKwargs")
+
+    proc = _ProcWithoutUnpack()
+    keys = get_processor_kwargs_from_processor(proc)
+    _assert_has_all_expected(keys)