core[patch]: Message content as positional arg (#16921)

libs/core/langchain_core/messages/base.py

@@ -28,6 +28,12 @@ class BaseMessage(Serializable):
     class Config:
         extra = Extra.allow
 
+    def __init__(
+        self, content: Union[str, List[Union[str, Dict]]], **kwargs: Any
+    ) -> None:
+        """Pass in content as positional arg."""
+        return super().__init__(content=content, **kwargs)
+
     @classmethod
     def is_lc_serializable(cls) -> bool:
         """Return whether this class is serializable."""

libs/core/langchain_core/prompt_values.py

@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 from abc import ABC, abstractmethod
-from typing import List, Literal, Sequence
+from typing import List, Literal, Sequence, cast
 
 from typing_extensions import TypedDict
 
@@ -105,7 +105,7 @@ class ImagePromptValue(PromptValue):
 
     def to_messages(self) -> List[BaseMessage]:
         """Return prompt as messages."""
-        return [HumanMessage(content=[self.image_url])]
+        return [HumanMessage(content=[cast(dict, self.image_url)])]
 
 
 class ChatPromptValueConcrete(ChatPromptValue):

libs/core/langchain_core/prompts/chat.py

@@ -446,7 +446,7 @@ class _StringImageMessagePromptTemplate(BaseMessagePromptTemplate):
                 content=text, additional_kwargs=self.additional_kwargs
             )
         else:
-            content = []
+            content: List = []
             for prompt in self.prompt:
                 inputs = {var: kwargs[var] for var in prompt.input_variables}
                 if isinstance(prompt, StringPromptTemplate):