[quality] the 'could not list the repository labels' arms (labeling.ts assertLabelsExist, labelSync.ts) have no end-to-end coverage #387

Finding

Two production catch arms rethrow a failed read of the repository's label catalog (GET /repos/{owner}/{repo}/labels) and neither is reached by the bundle suite:

Evidence (main @ aa6a0f8, Node v26.10.0, vitest 5.0.3):

• Unit: npx vitest run --coverage → 100 % lines; both arms are covered by __tests__/utils/utilsErrorPaths.test.ts and __tests__/cronJobs/ via a mocked octokit.
• End-to-end: npm run test:coverage:e2e on a scratch branch = origin/main + the heads of all 33 open hold-gated bundle PRs (test(bundle): drive root-OWNERS authorization on an issue and the OWNERS-based /lgtm refusal through dist/index.js #283 … test(bundle): drive the sweep cron's enqueued outcome (sweep.ts:75) through dist/index.js #385; 53 files / 420 tests pass) → labelSync.ts 97.91 % lines with only line 55 uncovered, labeling.ts 84.61 % with 135 among the uncovered lines. Every existing bundle test routes GET /labels to 200 (labelWriteRefused.test.ts, labelSyncFailureArms.test.ts on test(bundle): drive label-sync's refused-write and description-drift arms through dist/index.js #312, bundle.test.ts), so no fixture ever makes the catalog read fail.
• Reachability: both arms sit directly on the API call with no inner try, so a 500 from the fake GitHub drives them; @octokit/rest does not retry without the retry plugin.

Unlike the arms in #386, these are reachable from the shipped bundle: a GitHub API outage during a label command surfaces exactly this message to the user, so the wording and the no-write guarantee are worth pinning end-to-end.

Recommendation

One new bundle test file, nothing else touched:

• __tests__/bundle/labelListingRefused.test.ts: /kind cleanup with GET /labels → 500 fails with error handling issue comment: Error: could not list the repository labels: HttpError: boom and makes no write; jobs: label-sync with the same route fails with error handling cron job: Error: could not list the repository labels: HttpError: boom and makes no POST/PATCH.

Cluster: label-catalog read failure — disjoint from #312 (label-sync write refusals / description drift) and from the /kind write refusal in labelWriteRefused.test.ts.

Priority

• Impact: medium (covered by unit tests, not end-to-end)
• Effort: low

Filed by quality agent (hold-gated mode)

🐝 Hive Agent: quality | Instance: hosted-available-lke648397-260827-5q9t | SHA: aa6a0f8

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