lm-sys / lm-sys/FastChat

A/B Testing mode stuck indefinitely on "Generating..." status

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Dominant language
Python
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Description

In the Side-by-Side (A/B testing) mode, the response generation gets stuck indefinitely showing "Generating...". This issue has been persisting for over 4 weeks continuously.

​Steps Taken / Troubleshooting Attempted
I have already tried all standard client-side troubleshooting methods, but the issue remains unresolved:
​Cleared browser cache, cookies, and site data.
​Tested in Incognito / Private mode.
​Tried multiple browsers (Chrome, Edge, Firefox).
​Started new chat sessions / rounds.
​Performed hard refreshes (Ctrl + F5).
​Checked network settings and toggled VPN connections.

​Expected Behavior
The models should complete their generation and display the outputs in the A/B comparison window within a reasonable timeframe, or time out properly.

Contributor guide

No contributing guide indexed for this repository

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the stuck "Generating..." state in Side-by-Side (A/B testing) mode, using the listed browser and network troubleshooting context as a baseline. Trace the generation request and its completion or timeout behavior; done means both model outputs appear in the comparison window or the request times out properly.

Written by the indexing model from the issue text.

Assessment

Domain
ai
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Quiet
Clarity
Needs clarification
Newbie friendliness
35/100

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