The earlier build-script fix only watched .git/HEAD, which catches
branch switches and detached-HEAD moves but NOT git commit on the
current branch — the commit updates the underlying ref file
(refs/heads/<name> or packed-refs after pack-refs), and HEAD itself
stays unchanged. So the embedded short-SHA in deepseek --version went
stale on the same-branch-commit case the fix was supposed to cover.
Resolve the symbolic ref at build time and watch:
- the loose ref file (refs/heads/<branch>)
- packed-refs (Cargo treats a non-existent rerun-if-changed path as
always-changed, which covers the loose to packed transition after
git pack-refs)
Detached HEAD is unchanged: HEAD itself contains a SHA, no symbolic
deref happens, and HEAD-as-watched still triggers on every move.
Adds parse_symbolic_ref + 4 unit tests covering: stripped prefix,
no trailing newline, detached SHA, empty input.
Smoke verified: with the previous fix, an empty commit on the same
branch did not bust the cache. With this commit, it does.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Hunter Bown
870bc2ab20