Error building Component Message History

[tzengshinfu]

Bug Description

There is an existing RAG workflow, with the component arrangement roughly as follows: [Chat Input]─►[Ollama Embedding]─►[PGVector]─►[Parse Data]─►[Prompt]─►[Ollama]─►[Chat Output]

Now, I want to add the ability to remember the previous conversation. So, in [Chat Input]─►[Ollama Embedding]─►[PGVector]─►[Parse Data]─►[Prompt]─►[Ollama]─►[Chat Output]                                                                                                                                        ▲                                                                                                                                         │(System Message)                                                                     (added) [Message History]─►[Prompt2]─┘

I found that the [Message History] component encountered a compilation error.

Reproduction

1. Import the workflow file search_helper.json.
2. Add the [Message History] and [Prompt] components.
3. Edit the [Prompt] component to include the {memory} variable.
4. Connect the [Message History] and [Prompt] components to [Ollama](Input:System Message).
5. Start the Playground, and an error is displayed as shown in error.log.

Expected behavior

The Playground feature works properly.

Who can help?

No response

Operating System

Ubuntu Linux 20.04

Langflow Version

1.1.1

Python Version

None

Screenshot

playground_error

flow_layout

Flow File

flow_file search_helper.json

error.log error.log