[quality] owners-label's early-return and failure arms are never driven through dist/index.js (e2e 80% lines, unit 100%) #297

Finding

src/plugins/ownersLabel.ts is the pull_request owners-label plugin. The unit suite covers it fully, but the end-to-end bundle suite (__tests__/bundle, the only place the shipped dist/index.js runs) only reaches its happy path — adding a declared label the pull request lacks. The arms that stop short of a write are never driven through the bundle:

Evidence (main @ 3fc21f2, Node v26.10.0, vitest 5.0.3, @vitest/coverage-v8 5.0.3):

• Unit: npx vitest run --coverage (81 files / 1644 tests) → ownersLabel.ts 100 % lines / 100 % branches / 100 % functions.
• End-to-end: npm run test:coverage:e2e (vitest.e2e-coverage.config.mjs, __tests__/bundle, 5 files / 142 tests) → ownersLabel.ts 80 % lines / 73.33 % branches, uncovered lines 30, 61-62, 70, 77-78, 81.
• The two sources are analysed separately: their statement maps come from different transforms and do not line-merge ([quality] the bundle e2e suite's coverage of src/ is never captured — runBundle.ts drops NODE_V8_COVERAGE and dist/ has no source map #235).

Covered by unit but not end-to-end → priority 2 (medium) under the coverage evidence rules.

Recommendation

Add __tests__/bundle/ownersLabelArms.test.ts driving dist/index.js on pull_request synchronize (so require-matching-label, blunderbuss and tide stay out of the call list) against fakeGithub:

• already-carrying case (Area/SDK on the issue vs area/sdk in OWNERS): asserts no GET /labels, no POST …/labels
• every declared label unknown to the repository: asserts both skipping label … info lines and no write
• mixed known/unknown: asserts only the known one is posted, in the OWNERS spelling
• GET /labels → 500: asserts ::error::error handling pull_request event: could not list the repository labels: … and that approve's probe still runs after it
• payload without pull_request: asserts the missing pull request failure with no API calls

Disjoint from every open hold-gated bundle PR (#242 cron jobs input, #244 /meow, #246 fixed/prefixed labels + helpers.ts, #283 OWNERS authorization, #286 approve.github_review, #289 tide merge gate, #291 blunderbuss, #293 hold/sweep, #296 close/milestone): none drives owners-label's non-write arms, and helpers.ts is not touched.

Priority

• Impact: medium
• Effort: low

Filed by quality agent (hold-gated mode)

🐝 Hive Agent: quality | Instance: hosted-available-lke648397-260827-5q9t | SHA: 3fc21f2

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