x

libs/core/langchain_core/runnables/history.py

@@ -372,6 +372,7 @@ class RunnableWithMessageHistory(RunnableBindingBase):
     ) -> List[BaseMessage]:
         from langchain_core.messages import BaseMessage
 
+        # If dictionary, try to pluck the single key representing messages
         if isinstance(input_val, dict):
             if self.input_messages_key:
                 key = self.input_messages_key
@@ -381,13 +382,25 @@ class RunnableWithMessageHistory(RunnableBindingBase):
                 key = "input"
             input_val = input_val[key]
 
+        # If value is a string, convert to a human message
         if isinstance(input_val, str):
             from langchain_core.messages import HumanMessage
 
             return [HumanMessage(content=input_val)]
+        # If value is a single message, convert to a list
         elif isinstance(input_val, BaseMessage):
             return [input_val]
+        # If value is a list or tuple...
         elif isinstance(input_val, (list, tuple)):
+            # Handle empty case
+            if len(input_val) == 0:
+                return list(input_val)
+            # If is a list of list, then return the first value
+            # This occurs for chat models - since we batch inputs
+            if isinstance(input_val[0], list):
+                if len(input_val) != 1:
+                    raise ValueError()
+                return input_val[0]
             return list(input_val)
         else:
             raise ValueError(
@@ -400,6 +413,7 @@ class RunnableWithMessageHistory(RunnableBindingBase):
     ) -> List[BaseMessage]:
         from langchain_core.messages import BaseMessage
 
+        # If dictionary, try to pluck the single key representing messages
         if isinstance(output_val, dict):
             if self.output_messages_key:
                 key = self.output_messages_key
@@ -418,6 +432,7 @@ class RunnableWithMessageHistory(RunnableBindingBase):
             from langchain_core.messages import AIMessage
 
             return [AIMessage(content=output_val)]
+        # If value is a single message, convert to a list
         elif isinstance(output_val, BaseMessage):
             return [output_val]
         elif isinstance(output_val, (list, tuple)):
@@ -431,7 +446,10 @@ class RunnableWithMessageHistory(RunnableBindingBase):
 
         if not self.history_messages_key:
             # return all messages
-            messages += self._get_input_messages(input)
+            input_val = (
+                input if not self.input_messages_key else input[self.input_messages_key]
+            )
+            messages += self._get_input_messages(input_val)
         return messages
 
     async def _aenter_history(
@@ -454,7 +472,6 @@ class RunnableWithMessageHistory(RunnableBindingBase):
         # Get the input messages
         inputs = load(run.inputs)
         input_messages = self._get_input_messages(inputs)
-
         # If historic messages were prepended to the input messages, remove them to
         # avoid adding duplicate messages to history.
         if not self.history_messages_key:
@@ -466,23 +483,6 @@ class RunnableWithMessageHistory(RunnableBindingBase):
         output_messages = self._get_output_messages(output_val)
         hist.add_messages(input_messages + output_messages)
 
-    async def _aexit_history(self, run: Run, config: RunnableConfig) -> None:
-        hist: BaseChatMessageHistory = config["configurable"]["message_history"]
-
-        # Get the input messages
-        inputs = load(run.inputs)
-        input_messages = self._get_input_messages(inputs)
-
-        # If historic messages were prepended to the input messages, remove them to
-        # avoid adding duplicate messages to history.
-        if not self.history_messages_key:
-            historic_messages = config["configurable"]["message_history"].messages
-            input_messages = input_messages[len(historic_messages) :]
-
-        # Get the output messages
-        output_val = load(run.outputs)
-        output_messages = self._get_output_messages(output_val)
-        await hist.aadd_messages(input_messages + output_messages)
     def _merge_configs(self, *configs: Optional[RunnableConfig]) -> RunnableConfig:
         config = super()._merge_configs(*configs)
         expected_keys = [field_spec.id for field_spec in self.history_factory_config]

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

@@ -1,7 +1,5 @@
 from typing import Any, Callable, Dict, List, Optional, Sequence, Union
 
-from langchain_core.pydantic_v1 import Field
-
 from langchain_core.callbacks import (
     CallbackManagerForLLMRun,
 )
@@ -9,7 +7,7 @@ from langchain_core.chat_history import BaseChatMessageHistory
 from langchain_core.language_models.chat_models import BaseChatModel
 from langchain_core.messages import AIMessage, BaseMessage, HumanMessage, SystemMessage
 from langchain_core.outputs import ChatGeneration, ChatResult
-from langchain_core.pydantic_v1 import BaseModel
+from langchain_core.pydantic_v1 import BaseModel, Field
 from langchain_core.runnables.base import RunnableLambda
 from langchain_core.runnables.config import RunnableConfig
 from langchain_core.runnables.history import RunnableWithMessageHistory