Fix iOS TestFlight crash paths

[azooz2003-bit]

Summary

• Move libghostty iOS surface C callbacks out of GhosttySurfaceView.makeSurface(app:) into nonisolated top-level functions so off-main libghostty calls do not inherit UIView main-actor isolation.
• Add a focused iOS regression test that invokes the surface callbacks from a background queue.
• Replace raw SwiftUI Divider() context-menu separators in workspace group headers with Section groups to avoid UIKit context-menu layout aborts while measuring visible menu cells.

ASC evidence

• INTERNAL latest visible crash AGnxHSCbggL4TYIf5AxJkVM, created 2026-07-28T04:53:09.494Z, bundle dev.cmux.app.internal: EXC_CRASH (SIGABRT) during UIKit/SwiftUI context menu layout, with +[NSLayoutConstraint constraintWithItem:...] under -[UIContextMenuInteraction updateVisibleMenuWithBlock:] on thread 0.
• DEMO latest visible crash is still ADkFBL8Ch61FNTq2u4uRLHA, created 2026-07-26T00:36:17.844Z, bundle dev.cmux.app.demo: EXC_BREAKPOINT (SIGTRAP) on thread 8 at _dispatch_assert_queue_fail -> _swift_task_checkIsolatedSwift, mapped to the GhosttySurfaceView.makeSurface(app:) callback path and Surface.destroy.
• A newer DEMO report mentioned by dogfood was not visible in ASC when polled after the report.

Verification

• git diff --check origin/main...HEAD passed.
• xcodebuild -quiet test -workspace ios/cmux.xcworkspace -scheme cmux-ios -destination 'platform=iOS Simulator,id=38B83108-E1AD-44EB-B521-ACCB0C4C90E4' -derivedDataPath /tmp/cmux-ios-test-cr2-rebased '-only-testing:CmuxMobileTerminalTests/GhosttySurfaceCallbackTests/ghosttySurfaceCallbacksRunOffMainThread()' passed. xcresult summary: totalTestCount: 1, passedTests: 1, failedTests: 0.
• xcodebuild -quiet build -workspace ios/cmux.xcworkspace -scheme cmux-ios -configuration Release -destination 'generic/platform=iOS' -derivedDataPath /tmp/cmux-ios-build-cr2-rebased CODE_SIGNING_ALLOWED=NO exited 0.

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Summary by cubic

Fix two iOS crashes in TestFlight: off‑main libghostty surface callbacks violating main‑actor isolation, and context‑menu layout aborts in workspace group headers. Stabilizes surface IO and context menus.

• Bug Fixes
  • Centralized libghostty iOS surface C callbacks as nonisolated static C function pointers on GhosttySurfaceBridge (ioWriteCallback, renderPresentedCallback), and registered them from GhosttySurfaceView so off‑main calls don’t inherit UIView main‑actor isolation.
  • Replaced Divider() with Section groups in WorkspaceGroupHeaderRow context menus to avoid UIKit layout crashes.
  • Added GhosttySurfaceCallbackTests.ghosttySurfaceCallbacksRunOffMainThread() to verify callbacks safely run off the main thread.

^{Written for commit a751cb7. Summary will update on new commits.}

Summary by CodeRabbit

• Improvements
  • Reorganized workspace group context-menu actions into clearer, capability-based sections.
  • Improved organization of terminal surface callback handling to make input/render updates more reliable.
• Tests
  • Added coverage to confirm terminal surface callbacks execute on a background thread (not the main thread) to help keep the interface responsive.

[coderabbitai]

📝 Walkthrough

Walkthrough

The PR reorganizes workspace group context-menu actions into conditional sections and extracts Ghostty surface callbacks into named bridge functions, with a UIKit test verifying background-thread execution.

Changes

Workspace group menu

Layer / File(s)	Summary
Conditional context-menu sections Packages/iOS/CmuxMobileShellUI/Sources/CmuxMobileShellUI/WorkspaceGroupHeaderRow.swift	Groups pin/rename, new-workspace, and destructive actions into separate conditional Section blocks while preserving existing actions and state updates.

Ghostty surface callbacks

Layer / File(s)	Summary
Callback extraction and threading validation Packages/iOS/CmuxMobileTerminal/Sources/CmuxMobileTerminal/GhosttySurfaceBridge.swift, Packages/iOS/CmuxMobileTerminal/Sources/CmuxMobileTerminal/GhosttySurfaceView.swift, Packages/iOS/CmuxMobileTerminal/Tests/CmuxMobileTerminalTests/GhosttySurfaceCallbackTests.swift	Adds named callback entry points, wires them into surface creation, and tests invocation from a background queue.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Possibly related PRs

• manaflow-ai/cmux#8611: Related workspace group context-menu organization.
• manaflow-ai/cmux#8897: Related Ghostty callback registration and userdata handling.

Suggested reviewers: lawrencecchen

🚥 Pre-merge checks | ✅ 25

✅ Passed checks (25 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Cmux Swift Actor Isolation	✅ Passed	PASS: The diff only moves C callbacks into nonisolated bridge functions and adds a background-thread test; no new implicit MainActor models, unsafe Sendable refs, or bg UI-store access.
Cmux Swift Blocking Runtime	✅ Passed	PASS: No new blocking waits/sleeps/syncs/locks were introduced in production code; the only NSLock is pre-existing, and the new DispatchQueue usage is test-only scaffolding.
Cmux Browser Automation Off-Main	✅ Passed	No browser automation code changed; the diff only touches iOS Ghostty callbacks and context-menu sections, so the socket-worker routing rule is not implicated.
Cmux Expensive Synchronous Load	✅ Passed	Diff only groups menu sections and rewires Ghostty callbacks; no agent-history/session/transcript load was added or moved onto a main/interactive path.
Cmux Cache Substitution Correctness	✅ Passed	Diff only moves Ghostty C callbacks into static entry points and groups menu actions; no persistence/history/undo/snapshot read was swapped for a cache/opportunistic value.
Cmux No Hacky Sleeps	✅ Passed	Diff is Swift-only; the no-hacky-sleeps rule is out of scope here, and no new sleep/timer/polling delays were introduced.
Cmux Algorithmic Complexity	✅ Passed	No scalable-collection scans or hot-path sorting/filtering were added; the diff only refactors fixed-size context-menu sections and callback wiring.
Cmux Swift Concurrency	✅ Passed	Diff removes a production DispatchQueue.main.async and only adds test-only queue use at a callback boundary, which the rule explicitly allows.
Cmux Swift @Concurrent	✅ Passed	No changed async helper needs @concurrent; the new callbacks are synchronous C entry points, and the regression test explicitly hops to a background queue.
Cmux Swift Package Boundaries	✅ Passed	PASS: the diff is UI/menu wiring and Ghostty integration glue in package targets; no independently testable reusable domain logic was kept in the app target.
Cmux Swiftpm Lockfiles	✅ Passed	PR touches only Swift source/tests; no Package.swift, Package.resolved, .gitignore, or Xcode project/workflow files changed.
Cmux Swift Logging	✅ Passed	No added or changed print/debugPrint/dump/NSLog/Logger usage in the diff; only callback refactors and a test, so logging rules are satisfied.
Cmux User-Facing Error Privacy	✅ Passed	Diff only changes context-menu grouping and callback plumbing; no user-facing error, alert, command-output, or recovery copy was added or modified.
Cmux Full Internationalization	✅ Passed	No new user-facing copy was added; the workspace menu keeps existing L10n.string keys, and no xcstrings/locale files changed. Other edits are non-user-facing.
Cmux Swiftui State Layout	✅ Passed	No new SwiftUI state/layout anti-patterns were introduced; WorkspaceGroupHeaderRow only refactors contextMenu sections, and the other edits are UIKit bridge/test code.
Cmux Architecture Rethink	✅ Passed	Required platform bridge and context-menu layout fix; no sleeps, polling, duplicate wiring, or split ownership introduced, and async is test-only.
Cmux Swift Auxiliary Window Close Shortcuts	✅ Passed	Diff only refactors a context menu, Ghostty callbacks, and a test; no NSWindow/NSPanel/WindowGroup or cmuxAuxiliaryWindowIdentifiers changes.
Cmux Source Artifacts	✅ Passed	All changed paths are source/test files; no logs, caches, DerivedData, screenshots, or scratch/artifact dirs appear in the diff.
Cmux No Test Or Debug Seam In Production Source	✅ Passed	New callbacks are used by GhosttySurfaceView production code and tests; no #if DEBUG/test-only accessor or visibility-widening seam was added under Sources.
Cmux No Ambient Global State	✅ Passed	No new ambient globals appear: the Ghostty callbacks are static let constants inside GhosttySurfaceBridge, and no top-level mutable state or singleton was added.
Title check	✅ Passed	The title clearly and concisely summarizes the main change: fixing iOS TestFlight crash paths.
Description check	✅ Passed	Summary, ASC evidence, and verification are thorough, but the Demo Video, Review Trigger, and Checklist sections are missing.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix-ios-crash-r2

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In
`@Packages/iOS/CmuxMobileTerminal/Sources/CmuxMobileTerminal/GhosttySurfaceView.swift`:
- Around line 14-33: Move cmuxIOSurfaceIOWriteCallback and
cmuxIOSurfaceRenderPresentedCallback onto GhosttySurfaceBridge as nonisolated
static callback methods, preserving their existing callback behavior and
userdata handling. Update any callback registrations or references to use the
bridge-owned methods, and remove the top-level functions.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: c476565e-fe6b-43b6-ab43-03237959579a

📥 Commits

Reviewing files that changed from the base of the PR and between 0aec6ce and a4de568.

📒 Files selected for processing (3)

• Packages/iOS/CmuxMobileShellUI/Sources/CmuxMobileShellUI/WorkspaceGroupHeaderRow.swift
• Packages/iOS/CmuxMobileTerminal/Sources/CmuxMobileTerminal/GhosttySurfaceView.swift
• Packages/iOS/CmuxMobileTerminal/Tests/CmuxMobileTerminalTests/GhosttySurfaceCallbackTests.swift

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