Added chat history to codey models (#8831)

#7469

since 1.29.0, Vertex SDK supports a chat history provided to a codey
chat model.

Co-authored-by: Leonid Kuligin <kuligin@google.com>
Co-authored-by: Harrison Chase <hw.chase.17@gmail.com>

libs/langchain/langchain/chat_models/vertexai.py

@@ -111,7 +111,7 @@ class ChatVertexAI(_VertexAICommon, BaseChatModel):
 
                 values["client"] = ChatModel.from_pretrained(values["model_name"])
         except ImportError:
-            raise_vertex_import_error(minimum_expected_version="1.28.0")
+            raise_vertex_import_error(minimum_expected_version="1.29.0")
         return values
 
     def _generate(
@@ -155,7 +155,7 @@ class ChatVertexAI(_VertexAICommon, BaseChatModel):
                 context=context, message_history=history.history, **params
             )
         else:
-            chat = self.client.start_chat(**params)
+            chat = self.client.start_chat(message_history=history.history, **params)
         response = chat.send_message(question.content)
         text = self._enforce_stop_words(response.text, stop)
         return ChatResult(generations=[ChatGeneration(message=AIMessage(content=text))])

libs/langchain/tests/integration_tests/chat_models/test_vertexai.py

@@ -16,8 +16,12 @@ from langchain.chat_models.vertexai import _parse_chat_history, _parse_examples
 from langchain.schema.messages import AIMessage, HumanMessage, SystemMessage
 
 
-def test_vertexai_single_call() -> None:
-    model = ChatVertexAI()
+@pytest.mark.parametrize("model_name", [None, "codechat-bison", "chat-bison"])
+def test_vertexai_single_call(model_name: str) -> None:
+    if model_name:
+        model = ChatVertexAI(model_name=model_name)
+    else:
+        model = ChatVertexAI()
     message = HumanMessage(content="Hello")
     response = model([message])
     assert isinstance(response, AIMessage)
@@ -56,6 +60,22 @@ def test_vertexai_single_call_with_examples() -> None:
     assert isinstance(response.content, str)
 
 
+@pytest.mark.parametrize("model_name", [None, "codechat-bison", "chat-bison"])
+def test_vertexai_single_call_with_history(model_name: str) -> None:
+    if model_name:
+        model = ChatVertexAI(model_name=model_name)
+    else:
+        model = ChatVertexAI()
+    text_question1, text_answer1 = "How much is 2+2?", "4"
+    text_question2 = "How much is 3+3?"
+    message1 = HumanMessage(content=text_question1)
+    message2 = AIMessage(content=text_answer1)
+    message3 = HumanMessage(content=text_question2)
+    response = model([message1, message2, message3])
+    assert isinstance(response, AIMessage)
+    assert isinstance(response.content, str)
+
+
 def test_parse_chat_history_correct() -> None:
     from vertexai.language_models import ChatMessage
 
@@ -145,7 +165,7 @@ def test_parse_examples_correct() -> None:
     ]
 
 
-def test_parse_exmaples_failes_wrong_sequence() -> None:
+def test_parse_examples_failes_wrong_sequence() -> None:
     with pytest.raises(ValueError) as exc_info:
         _ = _parse_examples([AIMessage(content="a")])
     print(str(exc_info.value))