ci: route ci-macos.yml edits job by job so shard edits skip the Release build

[teamleaderleo]

An edit to .github/workflows/ci-macos.yml selected the macOS area and release_build whichever job it touched. Under full-ci, a PR that only changed the app-host unit-test shards paid for the Release build.

The changes job now passes the base ci-macos.yml to detect_ci_change_areas.py (--macos-workflow-base), which compares it with the PR's version job by job:

• Every ci-macos.yml edit still selects macOS.
• release_build is selected only when a changed job mentions release_build (release-admission, release-build, swift-package-tests, macos-status) or feeds a job gated on inputs.release_build through needs.X.outputs.
• An edit before jobs:, an unreadable file, a missing base, or a trusted base router that lacks the flag keeps the previous behaviour.

The ci.yml comparison in the detector now returns areas instead of a Linux-only flag. A caller job selects only the area of the workflow it calls (macos → macOS + Release, web → web, cli → CLI). Plainly Linux jobs still select nothing, and every other job still runs all areas. In CI this path only matters if ci.yml edits are ever sent through the detector: the changes step still removes ci.yml from the file list before routing.

Context: most unlabeled CI-only PRs already skip the compile through "Skip compile when build inputs are unchanged" (build fingerprint equal to the base's). The saving here is the Release build on full-ci PRs that edit ci-macos.yml, plus fewer jobs gated on macos.

Validation

• tests/test_ci_change_areas.py: 229 passed. The 7 new tests (job edits on the real ci.yml and ci-macos.yml, a synthetic outputs-feeder workflow, classify_files wiring, and the real changes step run in a temp repo on both router paths) fail at the first commit.
• All tests/test_ci_*.py: same 6 failures as origin/main (test_ci_canonical_build_root.py, environment), 836 passed.
• tests/test_ci_self_hosted_guard.sh passes.
• Not verified: a live CI run of a ci-macos.yml-only PR; actionlint (not installed where this was prepared).

🤖 Generated with Claude Code

https://claude.ai/code/session_012pAcDGiHaibDaMU4CPvXAP

---

Generated by Claude Code

---

^{Need help on this PR? Tag @codesmith-bot with what you need. Autofix is disabled.}

---

Summary by cubic

Routes CI workflow edits job by job so a ci-macos.yml change confined to the app-host unit-test shards no longer triggers the Release build.

• The detector now compares ci-macos.yml against the base revision per job; an edit selects macOS always, but release_build only when a Release job or a job whose outputs feed one changed.
• ci.yml edits select only the area of the reusable workflow the changed job calls (macOS, web, or CLI), instead of a Linux-only flag; routing jobs, the preamble, and unknown callers still select every area.
• Missing or unreadable base files keep the previous behavior (fail open).

^{Written for commit ecefaac. Summary will update on new commits.}

Summary by CodeRabbit

• Chores
  • CI checks now run based on which workflow jobs changed. Linux-only changes avoid product-area checks, while changes to macOS, web, or CLI jobs run checks for the affected areas.
  • macOS workflow changes run macOS checks; release build checks run when release jobs or their outputs are affected. If a workflow comparison is unavailable or unclear, CI runs broader checks.

[coderabbitai]

Navigate logical layers of code changes, visualize relationships, and explore their blast radius.

Note

Currently processing new changes in this PR. This may take a few minutes, please wait...

⚙️ Run configuration

Configuration used: Repository: manaflow-ai/cmux/.coderabbit.yaml

Review profile: ASSERTIVE

Plan: Advanced

Run ID: 86189d35-4b5e-43c4-90f1-405870ae9c49

📥 Commits

Reviewing files that changed from the base of the PR and between 832f621 and ecefaac.

📒 Files selected for processing (3)

• .github/workflows/ci.yml
• scripts/ci/detect_ci_change_areas.py
• tests/test_ci_change_areas.py

 ___________________________________________________
< Your TODOs are starting to look like a manifesto. >
 ---------------------------------------------------
  \
   \   \
        \ /\
        ( )
      .( o ).

✨ Finishing Touches

📝 Generate docstrings

• Commit to this branch
• Create a new PR

🧪 Generate unit tests (beta)

• Commit to this branch
• Create a new PR

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[github-actions]

All contributors have signed the CLA ✍️ ✅
_{Posted by the CLA Assistant Lite bot.}