Function commit_paths 

pub fn commit_paths(dir: &Path, paths: &[&str], message: &str) -> PathCommit

Stage paths and commit them alone (--only) in the checkout at dir, so another seat’s staged work is left out. The caller holds tracker_commit_lock. A git process outside ljos that holds the index is waited out with backoff. Paths left by an earlier deferral are committed in the same commit. An empty paths commits only those.

The add runs first and its failure stands on its own: a commit named for a file git never took in reports a pathspec error that hides why the add failed. An untracked file is added here, that file only. ljos never removes index.lock. That file belongs to the git that created it.