MongoDBChatMessageHistory saves History as a string rather than an object

[georgeherby]

Checked other resources

• I added a very descriptive title to this issue.
• I searched the LangChain documentation with the integrated search.
• I used the GitHub search to find a similar question and didn't find it.
• I am sure that this is a bug in LangChain rather than my code.
• The bug is not resolved by updating to the latest stable version of LangChain (or the specific integration package).

Example Code

                final_chain = ConversationalRetrievalChain.from_llm(
                    llm=llm,
                    retriever=retriever,
                    memory=memory,
                    verbose=True
                )

Error Message and Stack Trace (if applicable)

No response

Description

I am using MongoDBChatMessageHistory and it is working as expected in terms of functionality but I would expect the history record to be saved in an object in MongoDB rather than a string to aid with readability in the database.

(as an aside I am not sure why the fields are not snake or camelcase...)

System Info

langchain==0.1.13
langchain-community==0.0.29
langchain-core==0.1.36
langchain-mongodb==0.1.3
langchain-openai==0.1.1
langchain-text-splitters==0.0.1
langchainhub==0.1.15

[georgeherby]

This is still a problem..