Function branch_ref_exists 

pub fn branch_ref_exists(repo: &Path, branch: &str) -> bool

Whether branch resolves at repo, as a local head or as any remote-tracking ref. A repo git cannot read answers true, so a caller cleaning up on absence never discards state it failed to inspect.

Membership in repo_branch_names rather than a targeted for-each-ref pattern, so both callers share one parser. A pattern cannot answer this safely on a delete path: refs/remotes/*/<branch> has a * that does not cross /, so a remote named gh/upstream puts its refs where the pattern cannot see them, and a[b, a leading - or a space match nothing. Every one of those exits 0 with empty stdout, and empty is what triggers the delete.

Remote-tracking refs count because reap_worktree_branch deletes a local head whose commits are reachable from one, and a branch that survives on a remote is still open for review.