core[patch]: update some root_validators (#22787)

Update some of the @root_validators to be explicit pre=True or
pre=False, skip_on_failure=True for pydantic 2 compatibility.

libs/core/langchain_core/messages/ai.py

@@ -68,7 +68,7 @@ class AIMessage(BaseMessage):
             "invalid_tool_calls": self.invalid_tool_calls,
         }
 
-    @root_validator()
+    @root_validator(pre=True)
     def _backwards_compat_tool_calls(cls, values: dict) -> dict:
         raw_tool_calls = values.get("additional_kwargs", {}).get("tool_calls")
         tool_calls = (

libs/core/langchain_core/prompts/base.py

@@ -59,6 +59,29 @@ class BasePromptTemplate(
     tags: Optional[List[str]] = None
     """Tags to be used for tracing."""
 
+    @root_validator(pre=False, skip_on_failure=True)
+    def validate_variable_names(cls, values: Dict) -> Dict:
+        """Validate variable names do not include restricted names."""
+        if "stop" in values["input_variables"]:
+            raise ValueError(
+                "Cannot have an input variable named 'stop', as it is used internally,"
+                " please rename."
+            )
+        if "stop" in values["partial_variables"]:
+            raise ValueError(
+                "Cannot have an partial variable named 'stop', as it is used "
+                "internally, please rename."
+            )
+
+        overall = set(values["input_variables"]).intersection(
+            values["partial_variables"]
+        )
+        if overall:
+            raise ValueError(
+                f"Found overlapping input and partial variables: {overall}"
+            )
+        return values
+
     @classmethod
     def get_lc_namespace(cls) -> List[str]:
         """Get the namespace of the langchain object."""
@@ -155,29 +178,6 @@ class BasePromptTemplate(
         """Create Prompt Value."""
         return self.format_prompt(**kwargs)
 
-    @root_validator()
-    def validate_variable_names(cls, values: Dict) -> Dict:
-        """Validate variable names do not include restricted names."""
-        if "stop" in values["input_variables"]:
-            raise ValueError(
-                "Cannot have an input variable named 'stop', as it is used internally,"
-                " please rename."
-            )
-        if "stop" in values["partial_variables"]:
-            raise ValueError(
-                "Cannot have an partial variable named 'stop', as it is used "
-                "internally, please rename."
-            )
-
-        overall = set(values["input_variables"]).intersection(
-            values["partial_variables"]
-        )
-        if overall:
-            raise ValueError(
-                f"Found overlapping input and partial variables: {overall}"
-            )
-        return values
-
     def partial(self, **kwargs: Union[str, Callable[[], str]]) -> BasePromptTemplate:
         """Return a partial of the prompt template."""
         prompt_dict = self.__dict__.copy()

libs/core/langchain_core/tools.py

@@ -309,7 +309,7 @@ class ChildTool(BaseTool):
                 }
         return tool_input
 
-    @root_validator()
+    @root_validator(pre=True)
     def raise_deprecation(cls, values: Dict) -> Dict:
         """Raise deprecation warning if callback_manager is used."""
         if values.get("callback_manager") is not None:

libs/core/langchain_core/vectorstores.py

@@ -772,17 +772,17 @@ class VectorStoreRetriever(BaseRetriever):
 
         arbitrary_types_allowed = True
 
-    @root_validator()
+    @root_validator(pre=True)
     def validate_search_type(cls, values: Dict) -> Dict:
         """Validate search type."""
-        search_type = values["search_type"]
+        search_type = values.get("search_type", "similarity")
         if search_type not in cls.allowed_search_types:
             raise ValueError(
                 f"search_type of {search_type} not allowed. Valid values are: "
                 f"{cls.allowed_search_types}"
             )
         if search_type == "similarity_score_threshold":
-            score_threshold = values["search_kwargs"].get("score_threshold")
+            score_threshold = values.get("search_kwargs", {}).get("score_threshold")
             if (score_threshold is None) or (not isinstance(score_threshold, float)):
                 raise ValueError(
                     "`score_threshold` is not specified with a float value(0~1) "

libs/core/tests/unit_tests/runnables/test_configurable.py

@@ -23,7 +23,7 @@ class MyRunnable(RunnableSerializable[str, str]):
             raise ValueError("Cannot set _my_hidden_property")
         return values
 
-    @root_validator()
+    @root_validator(pre=False, skip_on_failure=True)
     def build_extra(cls, values: Dict[str, Any]) -> Dict[str, Any]:
         values["_my_hidden_property"] = values["my_property"]
         return values