Clear both chat history and conversation memory when /clear is applied

[srdas]

Addresses #616

1. Updated clear.py to clear chat history and display the help command again.
2. Updated base.py to remove conversation memory when chat history is cleared.

Use chat to ask questions and verify that the logs show it is using conversation memory to the default depth of k=2.

Then also check that /export contains the entire question history:

Next, use /clear and see that the next question does not have any conversation memory:

See the log message above: Clear conversation memory, re-initializing the llm chain.

Then check that /export only shows the new entries in chat:

This ensures that chat history and conversation memory are consistent.

[dlqqq]

@srdas Great work on this, thank you! I agree that this solution works in the default case, since DefaultChatHandler.create_llm_chain() always creates a new instance of ConversationBufferWindowMemory every call.

However, I've noticed that the LangChain chat history is actually split between the default and /ask chat handlers. Here is an excerpt /ask that shows it using its own separate memory, which will not be cleared in general:

class AskChatHandler(BaseChatHandler):
    ...

    def create_llm_chain(
        self, provider: Type[BaseProvider], provider_params: Dict[str, str]
    ):
        unified_parameters = {
            **provider_params,
            **(self.get_model_parameters(provider, provider_params)),
        }
        self.llm = provider(**unified_parameters)
        memory = ConversationBufferWindowMemory(
            memory_key="chat_history", return_messages=True, k=2
        )

Right now, default and /ask track two separate chat histories (one with all messages & replies to/from default, the other to/from /ask).

Ideally there should only be one instance of ConversationBufferWindowMemory shared between all chat handlers. I think the best way to do this is to define the memory as a class attribute on BaseChatHandler. This effectively shares global state between all chat handlers.

Under this proposal, BaseChatHandler should define three new methods:

1. get_memory(): returns BaseChatHandler.memory (not self.memory)
2. reset_memory(): sets BaseChatHandler.memory = ConversationBufferWindowMemory(return_messages=self.llm.is_chat_provider, k=2)
3. clear_memory(): calls BaseChatHandler.memory.clear()

Furthermore:

1. self.get_memory() should be called by create_llm_chain() in default and /ask
2. self.reset_memory() should be called by BaseChatHandler.get_llm_chain() right before calling self.create_llm_chain() when switching LLMs
3. self.clear_memory() should be called by /clear

Also note:

• The PROMPT_TEMPLATE in ask.py should change {chat_history} to {history} under this proposal. This is because the memory object in /ask defines memory_key='chat_history' instead of leaving it unset and defaulting to memory_key='history'.

Can you explore this implementation?

[srdas]

Thanks @dlqqq @3coins for the comments, I will refactor all the code to address the expanded intended functionality, i.e., to clear both default and ask chat histories as well as the related conversation memories.

[srdas]

I am closing this PR as the code base has changed since this was opened and it needs a fresh PR, as this one is outdated.