[Bugfix][Qwen3-TTS] Gate async-chunk Code2Wav on non_streaming_mode (#4371) (#6898)

Signed-off-by: Zhichao Zhang <60429419+smartDream-chao@users.noreply.github.com>

tests/entrypoints/openai_api/test_serving_speech.py

@@ -2241,6 +2241,7 @@ class TestTTSMethods:
 
         assert params["task_type"] == ["Base"]
         assert params["non_streaming_mode"] == [True]
+        assert "full_utterance_decode" not in params
 
     def test_build_tts_params_base_omits_non_streaming_mode_by_default(self, speech_server):
         """Base task should keep using the model default when no override is sent."""
@@ -2255,6 +2256,7 @@ class TestTTSMethods:
 
         assert params["task_type"] == ["Base"]
         assert "non_streaming_mode" not in params
+        assert "full_utterance_decode" not in params
 
     def test_build_tts_params_explicit_non_streaming_mode_overrides_voicedesign_default(self, speech_server):
         """Explicit false should not be replaced by the VoiceDesign fallback."""
@@ -2269,6 +2271,38 @@ class TestTTSMethods:
 
         assert params["task_type"] == ["VoiceDesign"]
         assert params["non_streaming_mode"] == [False]
+        assert "full_utterance_decode" not in params
+
+    def test_build_tts_params_streaming_voicedesign_keeps_prompt_mode_not_full_decode(self, speech_server):
+        """Streaming VoiceDesign defaults: prompt-mode True, no full_utterance_decode."""
+        req = OpenAICreateSpeechRequest(
+            input="Hello",
+            task_type="VoiceDesign",
+            instructions="warm and calm",
+            stream=True,
+            response_format="pcm",
+        )
+
+        params = speech_server._build_tts_params(req)
+
+        assert params["task_type"] == ["VoiceDesign"]
+        assert params["non_streaming_mode"] == [True]
+        assert "full_utterance_decode" not in params
+
+    def test_build_tts_params_streaming_customvoice_explicit_non_streaming_mode_still_windowed(self, speech_server):
+        """Explicit non_streaming_mode=True must not inject full_utterance_decode."""
+        req = OpenAICreateSpeechRequest(
+            input="Hello",
+            voice="Vivian",
+            non_streaming_mode=True,
+            stream=True,
+            response_format="pcm",
+        )
+
+        params = speech_server._build_tts_params(req)
+
+        assert params["non_streaming_mode"] == [True]
+        assert "full_utterance_decode" not in params
 
     def test_load_supported_speakers(self, mocker: MockerFixture):
         """Test _load_supported_speakers."""
@@ -5287,9 +5321,34 @@ class TestTTSAsyncOffloading:
 
         assert tts_params["task_type"] == ["VoiceDesign"]
         assert tts_params["non_streaming_mode"] == [False]
+        assert "full_utterance_decode" not in tts_params
         prompt = qwen3_tts_server.engine_client.generate.call_args.kwargs["prompt"]
         assert prompt["additional_information"] is tts_params
         assert prompt["additional_information"]["non_streaming_mode"] == [False]
+        assert "full_utterance_decode" not in prompt["additional_information"]
+
+    def test_prepare_speech_generation_qwen3_streaming_voicedesign_default_params(
+        self, qwen3_tts_server, mocker: MockerFixture
+    ):
+        """Streaming VoiceDesign defaults keep prompt-mode True without full_utterance_decode."""
+        qwen3_tts_server._validate_tts_request = mocker.MagicMock(return_value=None)
+        qwen3_tts_server._estimate_prompt_len_async = mocker.AsyncMock(return_value=512)
+
+        request = OpenAICreateSpeechRequest(
+            input="hello",
+            task_type="VoiceDesign",
+            instructions="warm and calm",
+            stream=True,
+            response_format="pcm",
+        )
+        _request_id, _generator, tts_params = asyncio.run(qwen3_tts_server._prepare_speech_generation(request))
+
+        assert tts_params["task_type"] == ["VoiceDesign"]
+        assert tts_params["non_streaming_mode"] == [True]
+        assert "full_utterance_decode" not in tts_params
+        prompt = qwen3_tts_server.engine_client.generate.call_args.kwargs["prompt"]
+        assert prompt["additional_information"]["non_streaming_mode"] == [True]
+        assert "full_utterance_decode" not in prompt["additional_information"]
 
     def test_prepare_speech_generation_qwen3_base_non_streaming_mode_true(
         self, qwen3_tts_server, mocker: MockerFixture
@@ -5312,9 +5371,11 @@ class TestTTSAsyncOffloading:
         assert tts_params["task_type"] == ["Base"]
         assert tts_params["ref_text"] == ["reference transcript"]
         assert tts_params["non_streaming_mode"] == [True]
+        assert "full_utterance_decode" not in tts_params
         prompt = qwen3_tts_server.engine_client.generate.call_args.kwargs["prompt"]
         assert prompt["additional_information"] is tts_params
         assert prompt["additional_information"]["non_streaming_mode"] == [True]
+        assert "full_utterance_decode" not in prompt["additional_information"]
 
     def test_qwen3_repeated_ref_audio_hot_path_sends_cache_key_without_waveform(self, qwen3_tts_server):
         """After a ref artifact is marked ready, repeated requests avoid ref_audio payload IPC."""