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[quality] owners.ts: 13 behavioural mutants survive the suite, incl. a shared group cache key that gives every team the first team's members #574
Description
Finding
Running the bounded Stryker harness proposed in #572 against src/utils/owners.ts (npx stryker run --mutate src/utils/owners.ts --force, Stryker 10.0.0, Vitest 5.0.4, main @ e3119ad) gives 332 mutants: 304 killed, 13 timed out, 15 survived (95.48%). Unit coverage of the file is 100/100/100/100 (npm run test:coverage @ e3119ad), so these are assertion gaps, not coverage gaps; the bundle suite runs the committed dist/index.js and cannot see a mutation of src/.
Thirteen of the survivors are behavioural (each applied by hand at its reported span and re-run to confirm):
| Site | Mutant | What goes unpinned |
|---|---|---|
owners.ts:151 memoized(groupCache, \${owner}/${slug}`, …)` |
key → ''
|
Every team shares one cache entry: the second @org/team in an OWNERS set resolves to the first team's members. No test expands two distinct teams in one run. |
owners.ts:99 parseGroup regex |
leading ^ removed |
alice@org/team is read as a group of org and a team is fetched for it |
owners.ts:52 options !== null
|
→ true
|
a bare options: key (YAML null) throws TypeError instead of meaning "no options" |
owners.ts:278 file.content === undefined
|
→ false
|
a blob with an encoding but no content fails with a Buffer TypeError, not "invalid OWNERS file returned from GitHub API for …" (only encoding-less blobs are tested) |
owners.ts:468 repository?.default_branch
|
?. → .
|
a payload with no repository at all throws instead of asking repos.get (every test payload carries a repository object) |
owners.ts:482 isNotFound (6 mutants) |
guards → true / &&→||
|
a string or null rejection from git.getTree is never exercised; several arms would throw TypeError: Cannot use 'in' operator instead of the listing error |
owners.ts:447 entry.path !== undefined
|
→ true
|
a tree entry without a path throws inside probeBranchOwners (the same guard in loadOwnersTree is pinned) |
owners.ts:398 hasOwnersCache key ${owner}/${repo}
|
→ ''
|
repoHasOwners answers a second repository from the first |
owners.ts:139 other-organization warning |
text → ''
|
the only user-facing hint that a group was ignored |
Not counted: owners.ts:161 (warning text, asserted exactly by held #564) and owners.ts:317 (core.debug text, equivalent by the review standard #572 documents).
Recommendation
Pin each contract in one new unit file, __tests__/utils/ownersGuards.test.ts, with direct expandGroups/parseOwners/loadOwnersTree/repoHasOwners/branchHasOwners calls (no src/ change). Re-running the harness with that file: 15 → 2 survivors (98.49%), both the exclusions above.
-
__tests__/utils/ownersGuards.test.tspins the 13 behavioural mutants listed above
Priority
- Impact: medium (the group-cache key is a real bug class for repositories that list two teams; the rest are guard contracts)
- Effort: low
Refs #554 ("Strengthen assertions and the test harness" — a consumer of the mutation harness, not a tracker box of its own).
Filed by quality agent (hold-gated mode)
🐝 Hive Agent: quality | Instance: hosted-available-lke648397-260827-5q9t | SHA: e3119ad
— hive: agent=quality backend=copilot model=claude-fable-5.1 copilot=1.0.88
Activity
github-actions commentedon Oct 24, 2026
Please add a kind label with
/kind feature,/kind failing-testor/kind cleanup.test: pin the Stryker survivors of nine modules (consolidates cncf#573,