[teamleaderleo]

Leo: "But why do you guys not just clean up after yourselves, or at least do your best to?" (on Swift suites that leave windows open for the suites after them)

This is the second of three. It follows #27172 (overlay host panels close with their window).

What leaked and why

The #27003 census at its head (fleet steps wleak-before-1/3/5) named 19 suites in this batch. Together they left 35 windows open at process exit. There were three causes:

• Teardowns that only order a window out. defer { window.orderOut(nil) } hides a window, but it stays open in NSApp.windows. Affected: AgentInteropAccessibility (2), FullScreenTitlebarPageMode (2), the Home suites' shell windows, HibernationWakeCover, HostPressureBannerToast and others. Fixed with close().
• Product popups that keep their panel between opens and only order it out. Page Info and the Extensions bubble (NativePopupHost) stayed open after their page closed: BrowserToolbarPressTarget 8, AgentPageStaysInWindow 2, DaemonClosedBrowserPage 2. The fix is the new NativePopupHost.closePanel(). BrowserPageRetirement (the page close path) now closes both bubbles for good. The host pressure popover closes its panel when its indicator leaves its window. The Mac screen approval prompt closes and drops its panel on hide. That panel held the prompt, so it stayed for good, and the next request makes a fresh one.
• Panels the code under test opens that the test never closed. These are the palette (BrowserProfileNewTabMenu, DebugPaletteCapture) and Home's Chief Settings popover (HomeOpenFocusesComposer; Home makes it up front and only ever hides it). The tests now close them through the product's own API in teardown.

Each suite now carries @Suite(.closesItsWindows), so a new leak fails that suite by name. No test is skipped and no assertion is changed.

No capture: no visible change. The popups look and open the same; only their hidden panels now close when their owner goes away.

Performance

Windows these 19 suites left open at process exit, from the fleet test census. Before is the #27003 head (steps wleak-before-1/3/5); after is step ef4421a6 at this tree, same filters.

metric	before	after	delta	harness
windows left open at exit, 19 suites	35	1	-34 (-97%)	package-test-lane.sh suite, steps wleak-before-1/3/5 / ef4421a6
BrowserToolbarPressTargetTests	8	0	-8	same
HomeOpenFocusesComposerTests	2	1	-1	same (that run was cut short; see below)

Known, not ours

• BackgroundAccessoryPolicyTests.aWindowClosedBeforeTheRestoreFinishesStaysClosed fails on the slower perf minis with the same two expectations and messages at base. The base runs that show it are steps fd82dc62 and 0d61f186, both pinned to the same worker; the test passes on faster workers at both base and head. It also leaves no window open now.
• HomeOpenFocusesComposerTests: the test process sometimes ends in the middle of openingAConversationFromTheList… (the run-loop stop its own doc comment describes). The harness window is then still open because its defer never ran. This happens at base too (wleak-before-1 and the batch base run). Runs that finish pass and leave 0 windows.

Risk

The product changes are small and only on close paths: a page's popup panels close when the page retires; the host pressure popover's panel closes when it leaves its window; the approval prompt's panel closes on hide. Each popup reopens with a fresh or reopened panel on its next show.

Agent session: agent session

🤖 Generated with Claude Code

---

Summary by cubic

Closes the windows these 19 cmux-next test suites leave open at process exit (35 open at exit down to 1), and makes the popup panels that caused most of the leak close for good when their owner goes away.

What leaked and why

• Teardowns that only ordered a window out hid it but left it in NSApp.windows; they now call close().
• Page Info, the Extensions bubble and the host pressure popover kept their panels between opens and only ordered them out; the new NativePopupHost.closePanel() now closes them when their page retires, when the indicator leaves its window, and when the Mac screen approval prompt hides (the prompt also drops its panel).
• Panels the tests themselves opened, the palette and Home's Chief Settings popover, are now closed in teardown through the product's own APIs.

Every suite carries @Suite(.closesItsWindows), so a new leak fails that suite by name. No test is skipped and no assertion changes.

^{Written for commit 7d6bea5. Summary will update on new commits.}

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[github-actions]

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

Review 7d6bea5: 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=pr27239 -f ref=window-leak-suites-B1 -f platform=macos -f backend_mode=local

red: cmux-next checks (god files, concurrency, crash safety, l10n); no finished base run on e219b3a to compare; do not merge until green; see lane-rules

[teamleaderleo]

Owned by an agent session · session

[blacksmith-sh]

Found 8 test failures on Blacksmith runners:

Failures

Test	View Logs
/tmp/tmpibw0cwww/summary-fail.json (live):/summary-fail.json (live):	View Logs
/tmp/tmpnl7to0au/summary-missing.json (live):/summary-missing.json (live):	View Logs
[new_workspaces] debug.new_workspace timed 0 of 50 new workspace rows/ [new_workspaces] debug.new_workspace timed 0 of 50 new workspace rows	View Logs
[new_workspaces] the window draws no frames/[new_workspaces] the window draws no frames	View Logs
[tabs] debug.tab_switch timed 0 of 40 switches/ [tabs] debug.tab_switch timed 0 of 40 switches	View Logs
[tabs] the window draws no frames/[tabs] the window draws no frames	View Logs
convention violations found (ERROR lines above)./ convention violations found (ERROR lines above).	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 (codex gpt-6-astra, high): SHIP at 2a4ec40

Independent Codex review of the full diff at this head, including the moved popup close in BrowserPageRetirement.close(). The reviewer found no blockers. BackgroundAccessoryPolicyTests.aWindowClosedBeforeTheRestoreFinishesStaysClosed fails the same way at base on the same worker.

[teamleaderleo]

Bead cx-t0qvou created for this PR by the cmux coordinator.

[teamleaderleo]

This PR conflicts with feat-cmux-next. Please resolve it with a normal merge commit (no force push) and get a fresh review at the new head. The window-leak series is the fix for the cmux-next swift test hang, where leaked windows starve the main thread and runs get cut short at 1500 s. Four UI PRs are blocked on it: #24073, #24295, #25978 and #26558. #27462 has merged, so a cut-short run now names its unfinished tests.

[teamleaderleo]

This change continues in #27257, which carries the same batch B1 window cleanup plus the repairs found in review (page-info certificate, site-settings and site-data windows now close with their tab). I'll close this PR with a link once #27257 lands; until then, review and land through #27257.

[teamleaderleo]

For awareness, from an audit against the aiforui course's popover rules (a popover inside another layer closes only itself; overflow fades at the edge, never a hard clip). This PR touches the same popup hosts, so these are yours to take or reject:

1. NativePopupHost.swift:139-142: a click inside a child panel dismisses the outer popup host as well. Expected: an outside click, Escape or a pick closes only the innermost layer. A popover opened from inside another must leave its container open.
2. WebPopupHost.swift:177-183: the native host has no edge mask where scrolling content is clipped. Expected: the clipped edge fades, matching the web ui-scroll-edge-fade that is in cmux NEXT: draggable Session Info cards and shared edge treatments #26720, and is never cut hard.

The audit is leaving both files alone while this PR is open, to avoid conflicts.

🤖 Generated with Claude Code

[teamleaderleo]

Review (codex gpt-6-astra high, next-review): SHIP at 7d6bea5

No blocking findings.

[cmux-bot]

cmux-bot approves 7d6bea5: an independent review passed this exact head (next-review receipt by teamleaderleo). A push needs a new review; a later BLOCK at this head dismisses this approval.

[github-actions]

Shipped in:

• cmux NEXT nightly 1.0.0-nightly.4097664234401 (167472006a)