community[patch]: add stop parameter support to volcengine maas (#19052)

- **Description:** add stop parameter to volcengine maas model
- **Dependencies:** no

---------

Co-authored-by: 江鹏飞 <jiangpengfei.jiangpf@bytedance.com>

libs/community/langchain_community/chat_models/volcengine_maas.py

@@ -112,6 +112,8 @@ class VolcEngineMaasChat(BaseChatModel, VolcEngineMaasBase):
         run_manager: Optional[CallbackManagerForLLMRun] = None,
         **kwargs: Any,
     ) -> Iterator[ChatGenerationChunk]:
+        if stop is not None:
+            kwargs["stop"] = stop
         params = self._convert_prompt_msg_params(messages, **kwargs)
         for res in self.client.stream_chat(params):
             if res:
@@ -133,6 +135,8 @@ class VolcEngineMaasChat(BaseChatModel, VolcEngineMaasBase):
             for chunk in self._stream(messages, stop, run_manager, **kwargs):
                 completion += chunk.text
         else:
+            if stop is not None:
+                kwargs["stop"] = stop
             params = self._convert_prompt_msg_params(messages, **kwargs)
             res = self.client.chat(params)
             msg = convert_dict_to_message(res)

libs/community/tests/integration_tests/chat_models/test_volcengine_maas.py

@@ -49,6 +49,28 @@ def test_stream() -> None:
     assert isinstance(response.content, str)
 
 
+def test_stop() -> None:
+    """Test that stop works."""
+    chat = VolcEngineMaasChat(
+        model="skylark2-pro-4k", model_version="1.2", streaming=True
+    )
+    callback_handler = FakeCallbackHandler()
+    callback_manager = CallbackManager([callback_handler])
+    response = chat(
+        messages=[
+            HumanMessage(content="repeat: hello world"),
+            AIMessage(content="hello world"),
+            HumanMessage(content="repeat: hello world"),
+        ],
+        stream=True,
+        callbacks=callback_manager,
+        stop=["world"],
+    )
+    assert callback_handler.llm_streams > 0
+    assert isinstance(response.content, str)
+    assert response.content.rstrip() == "hello"
+
+
 def test_multiple_messages() -> None:
     """Tests multiple messages works."""
     chat = VolcEngineMaasChat()