Codex app-server spins on repeated git rev-parse when workspace has invalid empty .git directory

Summary

If a Codex workspace contains a .git directory that exists but is not a valid Git repository, the local Codex app-server appears to enter a tight Git root detection loop. It repeatedly launches:

git -c core.hooksPath=/dev/null -c core.fsmonitor= rev-parse --show-toplevel

On my machine this kept the app-server around one CPU core continuously until the invalid .git directory was fixed.

Environment

• Codex CLI: codex-cli 0.142.4
• Build path indicated: 0.142.4-x86_64-unknown-linux-musl
• OS: Linux x86_64, Ubuntu kernel 7.0.0-27-generic
• Surface: Codex desktop/local app-server, process shown as codex app-server --listen unix://

Likely repro

1. Create or open a workspace directory that contains an empty/broken .git directory:

``bash
mkdir -p /tmp/codex-broken-git/.git
cd /tmp/codex-broken-git
git rev-parse --show-toplevel
``

1. Confirm Git exits with:

``text
fatal: not a git repository (or any of the parent directories): .git
``

1. Open that workspace in Codex desktop/app-server.
2. Watch the app-server process CPU and child process creation.

Observed behavior

• The app-server stayed hot for several minutes, typically around 90% to 160% CPU in interval readings.
• A short strace sample showed 1494 execve attempts involving git ... rev-parse --show-toplevel in roughly 3 seconds.
• The app-server repeatedly searched PATH for git, then launched /usr/bin/git.
• The loop persisted after the Codex log database was replaced with a fresh small database, so this did not appear to be caused by log DB corruption.
• Running git init in the affected workspace, turning the empty .git directory into valid Git metadata, immediately dropped app-server CPU from roughly one core to low single digits.

Expected behavior

Codex should treat an invalid .git directory as either:

• not a Git repository, or
• a recoverable workspace metadata error that is logged/surfaced once,

and then cache/back off the failed root detection. It should not continuously spawn git rev-parse in a tight loop.

Workaround

Either remove the broken .git directory or initialize/fix it:

rm -rf .git
# or
git init

After git init, the app-server CPU returned to normal.