Github CI Guardrails

GitHub CI Guardrails

1. Ensure change set is one logical unit (atomic commit).
2. Run local gates from references/local-gates.md.
3. Commitlint full PR range before push: npx commitlint --from origin/main --to HEAD --verbose
4. Validate GitHub checks with references/gh-ci-truth.md.
5. If checks fail, report failing job and log URL; map failure class via references/ci-pitfalls-pr-triage.md (commitlint scope, mutation surface, clippy duplicated_attributes, Jules force-push regression).
6. Do not claim green until gh pr checks shows no failures.

Mutation gate (fast in-diff)

• Score = killed / (killed + missed); threshold typically 85% (MUTATION_THRESHOLD).
• Minimize unrelated churn in the PR diff — cosmetic rewrites of adjacent functions put them in the mutant set (e.g. import_json -> Ok(1) survives a test that only imports one concept).
• Kill comparison boundary mutants when using select_nth_unstable_by(k): test the len == k path so > → >= panics and is caught.
• CLI async entry points (run_query -> Ok(())) are usually unkillable under --lib-only mutation CI; prefer exclude in scripts/mutation_test.sh with a one-line rationale, not path-excluding whole production modules.

Pre-merge re-check (multi-PR or bot PRs)

git fetch origin main
git diff --stat origin/main...HEAD   # unexpected reverts?
npx commitlint --from origin/main --to HEAD --verbose
gh pr checks <n>