[hivecommons-hive]

Test Improvement

Adds the bounded, repeatable mutation check that #554's "Strengthen assertions and the test harness" section asks for ("Establish bounded, repeatable mutation checks for selected high-risk behavior, with reproducible commands and reviewed equivalent-mutant exclusions. A repository-wide mutation gate is not required.").

Files / cluster claimed: stryker.config.mjs, vitest.mutation.config.mjs, package.json (test:mutation script + @stryker-mutator/core, @stryker-mutator/vitest-runner devDependencies), package-lock.json, .gitignore, docs/contributing.md (new "Mutation checks" section appended after the phantom-branches section — disjoint from #556's table-row edit), __tests__/utils/labelMatch.test.ts (matchesLabelPattern middle-part overlap). No src/ or dist/ change.

• npm run test:mutation runs StrykerJS over the merge-decision code: src/utils/mergeGate.ts, src/utils/labelMatch.ts, src/labels/hold.ts, src/utils/duration.ts. --mutate <file> probes any other file. coverageAnalysis: 'perTest', reports + incremental file in reports/mutation/ (ignored). No break threshold: this is a local/nightly-style check, not a per-push gate, per Follow-up: strengthen test contracts, CI enforcement, release delivery, and quality triage #554.
• vitest.mutation.config.mjs leaves out __tests__/bundle/** (the harness runs the committed dist/index.js, which no mutation of src/ can reach) and turns coverage off.
• Upstream bug shim. @stryker-mutator/vitest-runner 10.0.0 selects a mutant's tests with a testNamePattern of space-joined names; Vitest 5 matches that pattern against fullTestName, joined with " > " (node_modules/vitest/dist/task-utils.js createTaskName(names, separator = " > "), used by interpretTaskModes). Without the shim every mutant inside a describe() is reported Survived with 0 tests run — reproduced here: 123/151 survived, labelMatch.ts/mergeGate.ts 0 killed. Reported upstream as vitest-runner: on Vitest 5 the per-test name filter matches nothing, so every covered mutant survives (testNamePattern now joins the chain with ' > ') stryker-mutator/stryker-js#6210 (fix PRs fix(vitest-runner): match Vitest 5 test name separator when filtering tests stryker-mutator/stryker-js#6214, fix(vitest-runner): match nested test names joined with " > " (vitest 5) stryker-mutator/stryker-js#6247 and fix(vitest-runner): use native test names for Vitest 5 selection stryker-mutator/stryker-js#6260 open, unreleased). A configureVitest plugin hook rewrites each space in the pattern Stryker assigns to (?: > | ). The docs say to drop the shim once a vitest-runner release carries the fix.

First run (main @ e3119ad, Stryker 10.0.0, Vitest 5.0.4, Node 26)

File	Mutants	Killed	Survived
mergeGate.ts	24	24	0
labelMatch.ts	47	46 → 47	1 → 0
hold.ts	48	42	6
duration.ts	32	30	2

11 m 36 s on 2 workers. The one real survivor, labelMatch.ts:35 (at = found - part.length: a middle *-separated part could reuse characters of the part before it, so *ab*b* matched ab), is pinned by the new does not let a middle part reuse characters of the part before it case. The eight remaining survivors are reviewed in the docs table (two equivalent in duration.ts; six in hold.ts whose only observable is @actions/core's own error text, an issue_comment payload GitHub never sends, or a core.debug string).

Not in this PR

A scheduled CI lane for this command would be a .github/workflows/** change, which this agent's token cannot push; #554 says a repository-wide gate is not required, so none is proposed here.

Validation

• npm run test:mutation (twice: before the shim → 123 survived / 0 tests per runtime mutant; after → 142 killed; incremental re-run on labelMatch.ts after the new test → 47/47 killed)
• npx vitest run __tests__/utils/labelMatch.test.ts → 24 passed
• npx eslint stryker.config.mjs vitest.mutation.config.mjs __tests__/utils/labelMatch.test.ts docs/contributing.md → clean
• package-lock.json: 169 added entries, 0 removed, 4 @inquirer/* patch bumps pulled in by Stryker

Related Issue

Refs #554 — this lands the "bounded, repeatable mutation checks" box of the harness section; the tracker's CI-enforcement, release-delivery, remaining harness boxes (#569/#571 cover the unexpected-traffic ones) and routing sections stay open and are owned elsewhere.

---

Filed by quality agent (hold-gated mode). Human review required.

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

[hivecommons-hive]

Important

Held for human review by the hive's ACMM level gate.

This PR was opened by the "quality" agent while Hive policy required a human checkpoint for that agent. Agent PRs are held at ACMM L3–L5; an outreach PR that targets a repository this hive does not manage is held at every level because it publishes project-facing communication into someone else's project.

Hive will keep the hold label until a human removes it. Operators can make a deliberate one-off release during an ACMM level change with release_level_holds=true, but level changes never release this hold automatically.

[github-actions]

Please add a kind label with /kind feature, /kind failing-test or /kind cleanup.

[hivecommons-hive]

24dfbaf

ℹ️ Sentinel notice — informational; author is trusted (hive agent), merge is not blocked

Hive flagged this PR (author @hivecommons-hive[bot], head 24dfbaf13fdc) because it matches behaviors that can override security controls, escalate privileges or damage the codebase. This is a heuristic, not an accusation — a maintainer should confirm the change is intended before it merges.

• sensitive_path — changes 2 sensitive path(s) (Touches a sensitive path (OWNERS, workflows, policies, hive config, security docs, …))
  • package-lock.json
  • package.json

Hive did not add the sentinel-alert label because this author is trusted. The finding remains recorded for audit and the dashboard Security tab; set sentinel.trusted_authors_block: true to require the blocking label for trusted authors too.