[teamleaderleo]

The action catalog freshness check failed every pull request whose base had stale action exports (plans/cmux-next/action-surfaces.json, actions.md). That drift is the base's: direct pushes to feat-cmux-next change the catalog without regenerating, and the base autofix regenerates it afterwards (for example 573430f, c73892b). Until then, cmux-next generated files and cmux-next generated files (shared build) (#26687) went red on PRs that hadn't caused it. The settings export check already called this the base's; the action check didn't.

What changes

The actions step in swift-test, daemon-test and generated-files now runs scripts/cmux-next/judge-action-exports.sh, which wraps check-action-surfaces.sh:

1. The checks pass: done.
2. Otherwise it regenerates the exports and runs the checks again. If they're still red, that's a real catalog failure (a missing surface, a duplicate CLI name) and it fails as before.
3. If the checks were red only because of stale files, each stale export is judged against the base parent (HEAD^1):
   • It takes the base's drift (base committed to base fresh) and applies it to this commit's committed file (git merge-file).
   • If the result equals this commit's fresh export, only the base is stale. The step gives a base drift warning and puts the committed file back so nothing collects the base's repair.
   • Any other difference belongs to this change. The step fails naming the file, and the fresh export stays in the checkout for the existing "Regenerate stale files" step and patch artifact.

Where the base's fresh export comes from:

• If the change touched no generator input (Packages, plans/cmux-next, the regenerate script), it is this commit's own fresh export. No rebuild.
• Otherwise the changed inputs are checked out from HEAD^1 in place, rebuilt and exported. Then HEAD's inputs go back and are rebuilt. If that rebuild fails, .build is removed so later --skip-build suites can't test base binaries. This is the same restore discipline as check-settings-exports.sh.
• The rebuild runs only on a run that has stale exports and touched the inputs.

Step outcomes are unchanged: the step still fails exactly when the change's own exports are stale or the catalog is broken, so the regenerate, upload and verdict steps behave as before.

Tests

scripts/cmux-next/tests/judge-action-exports.test.sh is wired into the checks job. It uses a fake package whose generator reads the built product, so the base export really comes from a base rebuild. Each case is a merge commit, like a PR checkout:

case	result
(a) stale base, change touches no action input	passes with a base drift warning; checkout and products are HEAD's
(b) fresh base, catalog changed without regenerating	fails, naming the export
(c) base drift plus the change's own stale export	fails on the change's part
(d) base drift, change regenerated its own part	passes with a warning
(e) catalog failure that regenerating doesn't fix	fails
(f) fresh merge	passes silently
(g) base parent that doesn't build	counts as the change's; HEAD's products restored
(i) base regenerate rewrites an export that is fresh at HEAD	HEAD's bytes put back

Run on Linux CI: the bash test passes, shellcheck is clean, and test_cmux_next_generated_fold, test_cmux_next_checks_workflow, test_job_input_fingerprint, test_cmux_next_route, test_ci_workflow_guards_are_wired and test_check_paths pass (260 tests).

Why the drift keeps coming back

Direct pushes to feat-cmux-next get no PR checks. The base autofix is the self-heal for that, and branch protection on direct pushes is left as it is. This PR stops that drift from turning other PRs red.

Risk

The risk is a false pass, where a change's own stale export is called base drift. The 3-way comparison passes only when HEAD's fresh export is exactly the base's drift applied to HEAD's committed file. A merge conflict or any leftover difference fails. If the base doesn't build, the stale export counts as the change's.

Agent session: agent session

🤖 Generated with Claude Code

[teamleaderleo]

Owned by an agent session · session

[github-actions]

cmux status _{(one comment, edited in place; each line is updated by the job that owns it)}

Review 009f6c9: HQ feed card · gallery before/after runs · checks

App of this head (app.zip, kept 1 day)

gh workflow run reload-build.yml -R manaflow-ai/cmux --ref feat-cmux-next -f tag=pr26803 -f ref=leo/action-exports-base-drift -f platform=macos -f backend_mode=local

[blacksmith-sh]

Found 4 test failures on Blacksmith runners:

Failures

Test	View Logs
build_only must be a conjunctive exclusion on the helper, signing, and publication jobs , and must not gate the unsigned app build/ build_only must be a conjunctive exclusion on the helper, signing, and publication jobs , and must not gate the unsigned app build	View Logs
nightly.yml must derive the embedded key and sign every appcast through the helper/ nightly.yml must derive the embedded key and sign every appcast through the helper	View Logs
test_the_nightly_is_covered (main.NightlyStepCoverageTests.test_the_nightly_is_cove red)/ test_the_nightly_is_covered (main.NightlyStepCoverageTests.test_the_nightly_is_cove red)	View Logs
test_the_repository_highlights_validate (main.DigestTests.test_the_repository_highl ights_validate)/ test_the_repository_highlights_validate (main.DigestTests.test_the_repository_highl ights_validate)	View Logs

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

[teamleaderleo]

Bead cx-vg0efr created for this PR by the cmux coordinator.

[teamleaderleo]

Review (codex gpt-6-astra high, next-review): SHIP at 009f6c9

No blocking findings.

The bundled judge-action-exports test passes all cases.

[github-actions]

The feat-cmux-next push run https://github.com/manaflow-ai/cmux/actions/runs/40675011262 at c0d504c failed: cmux-next checks (god files, concurrency, crash safety, l10n).
Those jobs last passed at 853538a. This pull request is one of 2 merged since: #26803, #26536.
If the failure is in your change, fix forward on feat-cmux-next. Pull requests run only the tiers their paths reach (docs/ci/cmux-next-tiers.md); label a batch PR full-ci to run them all before merging.

[github-actions]

Shipped in:

• cmux NEXT nightly 1.0.0-nightly.4068813240101 (127a2705ef)
• cmux NEXT nightly 1.0.0-nightly.4069035197201 (2645001cde)