[quality] cronJobs: labelSync list failure and sweep non-Error/absent-field branches are untested #199

Finding

Unit coverage (npx vitest run --coverage, origin/main @ 187c5e3) leaves these branches in the cron jobs unexecuted:

• src/cronJobs/labelSync.ts:55 — octokit.paginate(listLabelsForRepo) rejecting, which should surface as could not list the repository labels: … and write nothing.
• src/cronJobs/sweep.ts:132 — a step rejecting with a non-Error value; the outcome should record String(e) under the step name.
• src/cronJobs/sweep.ts:141,153 — the pr.labels ?? [] / pr.requested_reviewers ?? [] fallbacks when the list payload omits those fields; ok-to-test must not call Actions and blunderbuss must still request reviewers.

Evidence provenance: single vitest suite (including __tests__/bundle) run by .github/workflows/test.yml (npm run test:coverage). The repository has no separate end-to-end coverage source, so no claim is made about e2e coverage.

Disjoint from open PRs #173–#198: none of them touch __tests__/cronJobTest/labelSync.test.ts or __tests__/cronJobTest/sweep.test.ts (#179 covers cronJobs/lgtm.ts; #196 covers the /check-required-labels sweep in handleIssueComment).

Recommendation

Add to __tests__/cronJobTest/labelSync.test.ts and __tests__/cronJobTest/sweep.test.ts:

• labelSync rejects with could not list the repository labels and makes no write when GET /repos/:o/:r/labels returns 500
• sweep records require-matching-label: <string> when enforceRequiredLabels rejects with a plain string
• sweep handles a listed pull request without labels/requested_reviewers: no Actions call, reviewers still requested

Priority

• Impact: medium (unit-covered files; error/defensive branches only)
• Effort: low

Filed by quality agent (hold-gated mode)

🐝 Hive Agent: quality | Instance: hosted-available-lke648397-260827-5q9t | SHA: 187c5e3

— hive: agent=quality backend=copilot model=claude-fable-5.1 copilot=1.0.88