fix(gemini): manifold cannot be used as a task model

[vysmaty]

Description:

I am encountering a warning when using Gemini models in Open WebUI. The issue manifests both in the user interface (UI) and in the backend logs.

Observed Behavior:

1. A frontend popup appears with the error message:
   There was a problem retrieving the messages from the backend database.
2. Concurrently, the following warning appears in the Open WebUI backend logs:
   Messages in the body (1) and messages in the database (3) do not match. This is likely due to a bug in Open WebUI. Cannot process files or filter citations.

Steps to Reproduce:

1. Open Open WebUI in your browser.
2. Select a Gemini-based model (e.g., gemini-2.5-flash).
3. Start a new conversation.
4. Send a second message .
5. After receiving reply no.

2 from AI, the error occurs.

Actual Result:

• Frontend: The following popup is displayed:

  There was a problem retrieving the messages from the backend database.
  

• Backend Log: The Open WebUI console/log shows this warning:

  2025-07-27 20:00:35.083 | WARNING  | function_gemini_manifold_google_genai:_fetch_and_validate_chat_history:205 - Messages in the body (1) and messages in the database (3) do not match. This is likely due to a bug in Open WebUI. Cannot process files or filter citations.
  

• Extract chat:
  chat-export-1753647680201.json
  chat-extract-html-element.txt

Expected Result:

• The conversation with the Gemini model should proceed smoothly without errors.
• No error popups or log warnings related to chat history mismatch should appear.
• All features, including file processing and citations, should be fully usable.

Environment:

• Open WebUI Version: v0.6.18

• Gemini Manifold google_genai Version: 1.22.0

• Open WebUI Installation Method: Docker

• Browser: Vivaldi 7.5.3735.54

• Gemini Model Used: gemini-2.5-flash

• Tested also on another device - Android

Additional Context / Questions:

The message Messages in the body (1) and messages in the database (3) do not match suggests a mismatch between the chat history state sent to the model and the state stored in the Open WebUI database. I would appreciate assistance in determining the root cause:

• Is this an Open WebUI database integrity issue?
• Or is the error caused by an incompatibility between Open WebUI version (v0.6.18) and Gemini Manifold / Google GenAI version (1.22.0)?

[suurt8ll]

Interesting, I can't reproduce this... Do you get the same error if you update your plugin to use code straight from the master branch?:

https://github.com/suurt8ll/open_webui_functions/blob/master/plugins/pipes/gemini_manifold.py

It contains some code that I'm still slowly working on, mainly Google Files API support, but if this one does not have this error then I know that something I did also fixed this error unintentionally.

[vysmaty]

I updated the code as instructed, and also:
I even tried going direct (bypassing the Traefik proxy) and in another browser (Chrome), but still got the same result.
And then, it finally clicked. The issue was my Task Model setup, which I'd also pulled from your pipe. I remember thinking, "Awesome, let's even use Gemma from same API!" That probably explains why the error only showed up with the second message.

I'm really sorry about this. 🙏 Could you please make a note of this case of error for other poor souls (like me!) so they don't bother you? 😇

[suurt8ll]

No that's actually a very useful find. I did not use this API as a task model so I missed this bug. I'll think of a way how to support using this manifold as a task model too.