Update @root_validators

libs/community/langchain_community/chat_models/snowflake.py

@@ -135,7 +135,7 @@ class ChatSnowflakeCortex(BaseChatModel):
         )
         return values
 
-    @root_validator()
+    @root_validator(pre=True)
     def validate_environment(cls, values: Dict) -> Dict:
         try:
             from snowflake.snowpark import Session

libs/community/langchain_community/chat_models/solar.py

@@ -37,7 +37,7 @@ class SolarChat(SolarCommon, ChatOpenAI):
         arbitrary_types_allowed = True
         extra = "ignore"
 
-    @root_validator()
+    @root_validator(pre=True)
     def validate_environment(cls, values: Dict) -> Dict:
         """Validate that the environment is set up correctly."""
         values["solar_api_key"] = get_from_dict_or_env(

libs/community/langchain_community/chat_models/tongyi.py

@@ -431,7 +431,7 @@ class ChatTongyi(BaseChatModel):
         """Return type of llm."""
         return "tongyi"
 
-    @root_validator()
+    @root_validator(pre=True)
     def validate_environment(cls, values: Dict) -> Dict:
         """Validate that api key and python package exists in environment."""
         values["dashscope_api_key"] = convert_to_secret_str(

libs/community/langchain_community/chat_models/vertexai.py

@@ -203,6 +203,9 @@ def _get_question(messages: List[BaseMessage]) -> HumanMessage:
     return question
 
 
+_DEFAULT_MODEL_NAME = "chat-bison"
+
+
 @deprecated(
     since="0.0.12",
     removal="0.3.0",
@@ -211,7 +214,7 @@ def _get_question(messages: List[BaseMessage]) -> HumanMessage:
 class ChatVertexAI(_VertexAICommon, BaseChatModel):
     """`Vertex AI` Chat large language models API."""
 
-    model_name: str = "chat-bison"
+    model_name: str = _DEFAULT_MODEL_NAME
     "Underlying model name."
     examples: Optional[List[BaseMessage]] = None
 
@@ -227,7 +230,7 @@ class ChatVertexAI(_VertexAICommon, BaseChatModel):
     @root_validator()
     def validate_environment(cls, values: Dict) -> Dict:
         """Validate that the python package exists in environment."""
-        is_gemini = is_gemini_model(values["model_name"])
+        is_gemini = is_gemini_model(values.get("model_name", _DEFAULT_MODEL_NAME))
         cls._try_init_vertexai(values)
         try:
             from vertexai.language_models import ChatModel, CodeChatModel

libs/community/langchain_community/chat_models/yuan2.py

@@ -165,7 +165,7 @@ class ChatYuan2(BaseChatModel):
         values["model_kwargs"] = extra
         return values
 
-    @root_validator()
+    @root_validator(pre=True)
     def validate_environment(cls, values: Dict) -> Dict:
         """Validate that api key and python package exists in environment."""
         values["yuan2_api_key"] = get_from_dict_or_env(