[teamleaderleo]

Leo’s request

Browser import and Extensions menu behavior should remain correct.

Change

Share the existing FrameBudgetCalibration with the Extensions menu performance suite. Keep the nominal 16 ms open, 50 ms first-open and 16 ms hover budgets; scale them by the same runner reference workload already used by sidebar tests. Runners over 4× nominal speed cost, or with excessively noisy samples, print a reason and skip the timed assertions. Functional assertions still run, including icon reuse and opening without waiting for Chromium.

The helper moves to Tests/CmuxNextTestSupport; only the browser and app test targets depend on it. Sidebar callers gain the import and retain the existing calibration logic. The build-input guard recognizes this reviewed test-only target because no shipped product links it, and the architecture map records it as a core helper. Two screen-independent tests exercise slow and fast runner behavior, and the old duration-assertion allowlist entry is removed.

Risk: test-only package wiring and performance-budget calibration. No product sources, visual design, new timers, observers or animation loops change. Calibration samples are synchronous and bounded to 15 measurements per checkpoint.

Validation

• Reconciled feat-cmux-next at 47b4dbb1c154c4c29c4802a2e0416ec450ff51b4; resolved Package.swift by retaining both sides’ dependencies. Diff: 11 files, +137/−40.
• python3 tests/test_dev_release_product_key.py: all 9 tests pass after recognizing the shared test-support target.
• The changed-file pre-push gate passes all scanners, SwiftFormat, SwiftLint and the architecture ratchet in 3.3 seconds.
• The fleet Release compile and cmux-next static gate passed at final head 323876d01f2088dc1a4cd9aa294c395c658bcc8a.
• Earlier same-harness scaling regression: disabling scaling failed at 6.06 ms against a 2.82 ms budget; with scaling the slow-runner stand-in passed at 5.28 ms against 2.59 ms nominal / 7.8 ms scaled. These are calibration tests, not evidence of a product speedup.

Known limit: the CPU reference cannot explain extra AppKit drawing cost on a nominal-speed runner; earlier first-open measurements of 51.3–54.6 ms still exceeded 50 ms with factor 1.00. Those base timing failures are separate from this calibration/wiring change. Related follow-up: #26303.

Agent session: agent session

[teamleaderleo]

Owned by cx4-bi24157 on huge-blue

[teamleaderleo]

Review (independent subagent): SHIP at f6fdee3

• Package.swift: CmuxNextTestSupport is a regular target under Tests/, linked into no product, and the dependency lists are sorted.
• The move: FrameBudgetCalibration is unchanged in logic apart from public and the Self.* helpers.
• Scaling: the factor is floored at 1, so a fast runner keeps the 16/50/16 ms budgets.
• Skips: only over 4x or on noisy samples, each with a printed reason.
• Tests: the stand-in tests are deterministic.
• Scope: no shipped code changes. The determinism allowlist finds the same set as base.

Not fixed here: aws-m4pro-9 is slow at drawing, not CPU (factor 1.00), so its first-open red stays (see "Not in this PR").

[teamleaderleo]

Bead cx-gx5fb created for this PR by the cmux coordinator.

[github-actions]

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

Review 323876d: 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=pr24157 -f ref=browser-import-2/extmenu-calibrate -f platform=macos -f backend_mode=local

web and size checks: green

[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]

Review (independent subagent): SHIP at 3a67073

The head is a merge of feat-cmux-next into the earlier reviewed head f6fdee3. The one conflict was in Package.swift: base added the test-only CmuxNextTestExitTrace target in the same place as this PR's CmuxNextTestSupport. The resolution keeps both.

• Merge: base's changes to Package.swift come through line for line, with nothing lost or duplicated. Both targets are listed in CmuxNextAppTests in sorted order, and check-package-dependency-lists.py exits 0.
• Diff against the merge base: the same 7 files (+133/−39) as the reviewed change. Nothing else came in through the merge.
• Name clashes: base has no other CmuxNextTestSupport and only one FrameBudgetCalibration, so nothing clashes.

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[teamleaderleo]

Review (independent subagent): SHIP at 9380e81

Since 3a67073 (shipped), this head merges feat-cmux-next again to pick up #24227's test-compile fix (the earlier fast tier and daemon reds were that base break, HoleRecordingPage). It also adds import CmuxNextTestSupport to SidebarHoverCardRetargetBenchTests.swift, a file base added that uses FrameBudgetCalibration after this PR moved the type into the new target.

• Imports: every test file that uses FrameBudgetCalibration or its moved helpers imports CmuxNextTestSupport. Every member they use is public, and both test targets list the module, in sorted order.
• Old helpers: SidebarScrollBench.threadCPU/percentile still exist and call through to the moved helpers. FrameBudgetCalibration is defined once.
• Merge: it brings in base changes only. The diff against base is the PR's 7 files plus the one import line.
• Dependency lists: check-package-dependency-lists.py exits 0.

[teamleaderleo]

cmux-next / cmux-next checks (god files, concurrency, crash safety, l10n) › Checks job structure is red on 12 of 14 fresh feat-cmux-next PR heads in the last 2:00:00, so it is most likely a base red, not this PR's. The base-reds lane has it; a base merge picks up the fix once it lands.

[teamleaderleo]

cmux-next / cmux-next checks (god files, concurrency, crash safety, l10n) › No fleet host names in gallery fixtures is red on 11 of 14 fresh feat-cmux-next PR heads in the last 2:00:00, so it is most likely a base red, not this PR's. The base-reds lane has it; a base merge picks up the fix once it lands.

[teamleaderleo]

cmux-next / cmux-next checks (god files, concurrency, crash safety, l10n) › No new SwiftUI (macOS UI is AppKit) is red on 12 of 14 fresh feat-cmux-next PR heads in the last 2:00:00, so it is most likely a base red, not this PR's. The base-reds lane has it; a base merge picks up the fix once it lands.

[teamleaderleo]

cmux-next guards / cmux-next page strings generate is red on 13 of 13 fresh feat-cmux-next PR heads in the last 2:00:00, so it is most likely a base red, not this PR's. The base-reds lane has it; a base merge picks up the fix once it lands.

[teamleaderleo]

cmux-next guards / nightly-guards / workflow-guard-tests / release-notary is red on 12 of 13 fresh feat-cmux-next PR heads in the last 2:00:00, so it is most likely a base red, not this PR's. The base-reds lane has it; a base merge picks up the fix once it lands.

[teamleaderleo]

Orphaned: no activity for 54 h, and no lane holds a lease on it. The orphan sweep could not merge feat-cmux-next in: conflicts in Packages/macOS/CmuxNext/Package.swift. Listed for a lane to resolve.

[teamleaderleo]

Review (codex gpt-6-astra xhigh, next-review): SHIP at e5308c8

No blocking findings.

The helper move preserves its logic, and callers have the required imports and dependencies. macOS tests could not be run in this Linux environment.

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[github-actions]

The feat-cmux-next push run https://github.com/manaflow-ai/cmux/actions/runs/40631829534 at 09b9b3f failed: cmux-next checks (god files, concurrency, crash safety, l10n).
Those jobs last passed at 03c0c73. This pull request is one of 2 merged since: #26400, #24157.
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)

[github-actions]

Shipped in:

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