Codex Desktop 26.810.41047 can resolve a tracked branch as refs/heads/HEAD when creating a permanent worktree

What version of the Codex App are you using?

Codex Desktop 26.810.41047.

What platform is your computer?

macOS.

What issue are you seeing?

Creating a permanent worktree can fail immediately with:

[info] Starting worktree creation
fatal: invalid reference: refs/heads/HEAD
[stderr] git worktree add failed: fatal: invalid reference: refs/heads/HEAD

The repository is not in detached HEAD state, and Git resolves the current branch correctly. After further testing, I can reproduce this in a minimal repository where the current local branch tracks an upstream branch.

Codex appears to end up treating the literal value HEAD as a local branch name and constructing the invalid ref refs/heads/HEAD.

Minimal reproduction

Create a completely new repository with one commit and a local bare remote:

rm -rf /tmp/codex-upstream-test /tmp/codex-upstream-remote.git

git init --bare /tmp/codex-upstream-remote.git
git clone /tmp/codex-upstream-remote.git /tmp/codex-upstream-test
cd /tmp/codex-upstream-test

git switch -c main
echo test > README.md
git add README.md
git commit -m "init"
git push -u origin main

Verify the repository is in a normal branch/tracking state:

$ git status -sb
## main...origin/main

$ git branch -vv
* main <commit> [origin/main] init

$ git rev-parse --abbrev-ref --symbolic-full-name '@{u}'
origin/main

Then:

1. Add /tmp/codex-upstream-test as a project in Codex Desktop.
2. Choose Create permanent worktree.
3. Worktree creation fails with:

fatal: invalid reference: refs/heads/HEAD

A/B testing

I also tested the behavior using fresh repositories and fresh clones to isolate the trigger.

The following Git operations all work correctly outside Codex:

git symbolic-ref HEAD
# refs/heads/main

git rev-parse --verify HEAD
# valid commit

git worktree add /tmp/codex-worktree-test --detach HEAD
# succeeds

Fresh clones and depth-1 shallow clones can still reproduce the Codex failure, so the issue is not explained by old worktree metadata, repository history size, or a damaged HEAD.

The most useful A/B result was:

• repository with a remote but no upstream configured for the current branch: permanent worktree creation succeeded
• same repository after setting the current branch to track origin/main: permanent worktree creation failed with refs/heads/HEAD

The tracking configuration itself was normal:

branch.main.remote = origin
branch.main.merge = refs/heads/main
upstream = origin/main

origin/HEAD was also valid and resolved to the expected branch, so this does not appear to be caused by a missing or broken origin/HEAD.

Expected behavior

Codex should resolve the selected/current local branch and create the permanent worktree from a valid revision/commit, regardless of whether that branch tracks an upstream remote branch.

Actual behavior

Under the reproducible tracked-branch case above, Codex passes or constructs:

refs/heads/HEAD

which is not a valid local branch ref in the repository, causing git worktree add to fail before the worktree is created.

Additional notes

This is reproducible in a newly created one-commit repository, so it is not specific to any particular project or repository.

The upstream relationship appears to be a reliable trigger in the A/B tests, but I am not claiming it is necessarily the underlying root cause; the bug may be in Codex's branch/ref resolution or cached project Git state.