[Hero-Gamer]

Update spec 2026-09-24 3.35PM ET

Aligned with #739 — Advisory Only ✅

• mutants-baseline-diff = reports, never blocks → exits 0 on new survivors
• Real errors (missing data/files) still fail → no silent misbehavior
• Mutant scanning → nightly mutants.yml; PR defense → ast-grep (lint: weak asserts outside test files, and a waiver date token #687)
• CI cycle fixed; baseline auto-initializes; no 25k-line file committed

---

Follow up from #688 item 1.3

What

• Restore clean ci.yml from upstream/master to fix 9x Expected — Waiting for status to be reported.
• Brings back required checks: qc, test, coverage, macos, windows, mutants (1/4), mutants (2/4), mutants (3/4), mutants (4/4).
• Ensures trigger is:

  on:
    push:
      branches: [master, main, "v*.*.x"]
    pull_request:

  so fork PRs report status instead of staying in Waiting.
• mutants job remains:
  • 4-way sharded matrix 0/4..3/4, name mutants (n/4)
  • needs: [qc, test] (overlaps coverage, does not wait for macos/windows)
  • small diffs (<400 lines): mutants (1/4) runs --shard 0/1, others exit 0
  • docs-only diffs exit 0
  • uploads mutants.out artifact
• If branch contains mutants-baseline-diff job + scripts/mutants-diff.py + docs/mutants/survivors-baseline.list, this PR keeps them:
  • mutants-baseline-diff needs [mutants], if: github.event_name == 'pull_request'
  • permissions: contents: read, issues: write, pull-requests: write
  • uses actions/download-artifact@v4 with pattern: mutants-out-*
  • scripts/mutants-diff.py handles first-run empty baseline, ignores # comments, deduplicates shards, skips target/

Why

Previous 13 commits deleted qc and introduced needs: [mutants] self-cycle / invalid YAML, so no jobs started on lint/* branches. Every push showed Failure lint/mutants-baseline-diff with no logs and Expected — Waiting for fmt, clippy, test, etc.

Correct DAG is: qc -> test -> mutants -> mutants-baseline-diff -> coverage

Verification

grep -n "^\s*[a-z0-9_-]*:\s*$" .github/workflows/ci.yml | head -n 20
python3 -c "import yaml,pathlib; yaml.safe_load(pathlib.Path('.github/workflows/ci.yml').read_text()); print('YAML OK')"
cargo fmt --all -- --check
git diff upstream/master --stat
# should NOT contain docs/mutants/all-mutants.list (25233 lines)

Actions now: 11 successful, 3 in progress (coverage, mutants 4/4, codeql), 4 skipped (core-functional, nixos-module-runtime, overlay-functional, warnet-example - expected for ci.yml-only diff).

Notes

• No production code change. No coverage impact.
• Docs-only diffs exit 0, weekly sweep stays mutants.yml.
• Owner: TESTING.md / docs/quality.md

[Hero-Gamer]

Updated — aligned fully with #739:

• mutants-diff.py: new survivors → exit 0 / advisory only — never blocks merge
• Real errors (missing data/artifacts) still fail → no silent misbehavior
• CI DAG fixed, baseline initializes automatically, shard merging intact
• This infrastructure is exactly what nightly scanning needs: artifact collection → baseline comparison → transparent reporting

[rearden-grok]

Thanks for putting this together and for working through the CI edge cases. We are going to use the overnight mutants runs to surface survivors and drive improvements over time, rather than maintain a checked-in survivor baseline or an advisory diff job, so I am closing this PR for now.