Codespaces sessions stall with “request cancelled”; diff counts grow and remain stuck on “Building diff” #4900

[automated]

Summary

Using GitHub Codespaces as a remote environment in the GitHub Copilot app is unreliable. A session initially works, but after some time the app stalls. Settings shows the Codespace environment with this error:

request cancelled

The Codespace itself remains running and otherwise works normally throughout. I cannot find a working way to reconnect within the running app. The Connect button is greyed out with a loading spinner.

Restarting the app reconnects to the Codespace, but then I have to restart all my sessions. This makes recovery disruptive even though the Codespace itself has remained available.

I also intermittently see the Changes count grow into hundreds of thousands of lines, while the diff view remains stuck on:

Building diff

These inflated counts do not correspond to changes I can see on the branch. I have observed this after the connection problem, but do not know whether the two symptoms share a cause.

Steps to reproduce

The problem is intermittent; I do not have a deterministic trigger.

1. Connect the GitHub Copilot app to a running Codespace as a remote environment.
2. Work in a session. It initially functions normally.
3. After some time, the app stalls.
4. Open Settings. The Codespace environment shows request cancelled, and I cannot reconnect within the running app.
5. Sometimes afterward, the Changes count starts climbing to very large values, and opening the diff view leaves it on Building diff.
6. Restart the app. It reconnects to the Codespace, but all sessions must then be restarted.

Expected behavior

• The app maintains its connection to a running Codespace, or provides a working way to reconnect and resume sessions without restarting the app and all sessions.
• Change counts reflect actual branch changes.
• The diff view loads, or displays an actionable error rather than remaining indefinitely on Building diff.

Actual behavior

• The app becomes unusable for the remote session even though the Codespace remains running and usable.
• Settings shows request cancelled, with no working reconnection path within the running app.
• Restarting the app restores the connection, but requires restarting all sessions.
• The Changes count can grow into hundreds of thousands of lines without corresponding visible branch changes.
• The diff view remains stuck on Building diff.

Screenshots

The screenshots show the environment's request cancelled error with a greyed-out Connect button, and an inflated Changes count of +210,649 / −53,931.

Environment

• Remote environment: GitHub Codespaces
• Affected app version and client OS/version: not recorded in this report.