Codex VSCode extension corrupts git repositories with `fatal: unable to read sha` and `fatal: Unable to create '.../.git/worktrees/foo/index.lock': File exists.`

What version of the IDE extension are you using?

26.506.31004

What subscription do you have?

Plus

Which IDE are you using?

VS Code

What platform is your computer?

Linux 6.19.14-200.fc43.x86_64 x86_64 unknown

What issue are you seeing?

See repro.

What steps can reproduce the bug?

Repro:

1. Use a git worktree (I'm using https://github.com/truffleruby/truffleruby a reasonable-size but not small git repository)
2. Configure:

git config --global core.editor 'code --wait'

1. Ensure VS Code is not already running
2. Run:

git commit enter a message in VSCode, quit with with e.g. Ctrl+W. Might happen more often when not taking long to write the commit message, and maybe also happens more with a larger git repository.

1. Observe:

fatal: unable to read <sha>
or:
fatal: Unable to create .../.git/worktrees/.../index.lock

Observations:

• Happens only on VS Code cold start, if VS Code is already running it seems fine
• git reset --hard HEAD seems to fix the git repository, or rm .../.git/worktrees/.../index.lock
• code --wait --disable-extensions --reuse-window fixes it
• Bisected to Codex extension, does not happen with the Codex extension disabled, happens more than half the tries with Codex extension enabled.

A workaround is export EDITOR='code --wait --disable-extensions --new-window' to disable all extensions, or disabling or uninstalling the Codex extension.

A possible cause might be that the Codex extension auto-refresh/git operations are racing on the worktree index during editor startup.

What is the expected behavior?

I would expect the Codex extension to never corrupt my git repository.

Also I expect the Codex extension does not do anything until I start using it, e.g. by opening the Codex chat panel and writing in it.

Additional information

_No response_