Swift Send button crashes when invoked through accessibility action

[dirvine]

Summary

During the two-machine UI stress test on macOS 26.4, the Swift app crashed when the channel composer Send button was invoked through Computer Use/accessibility (NSAccessibilityPerformAction). The same message sent successfully when the window was moved to the main display and the Send button was clicked with a normal mouse event.

Environment

• Local app: /Users/davidirvine/Applications/Communitas-Patched.app
• Bundle id: com.saorsalabs.communitas.patched
• App version/build: 0.11.8
• macOS: 26.4 (25E246)
• x0x local daemon: 0.21.2, healthy

Repro

1. Open Swift app and select a channel.
2. Enter codex-ui-swift-to-dioxus-20260606-0111 in the composer.
3. Invoke the Send button via accessibility action / Computer Use element click.

Actual

The app quit immediately. Crash report:
~/Library/Logs/DiagnosticReports/Communitas-2026-06-06-011212.ips

Key crash details:

• EXC_BAD_ACCESS / SIGSEGV
• faulting thread: com.apple.main-thread
• top frames include swift_getObjectType, swift_task_isMainExecutorImpl, MainActor.assumeIsolated, ButtonAction.callAsFunction, AccessibilityButtonModifier, NSAccessibilityPerformAction

Expected

Accessibility invocation should either send the message or fail gracefully. It should not terminate the app.

Additional evidence

A normal mouse click on the same visible Send button later sent codex-ui-swift-private-keysend-20260606-0117 successfully and displayed it locally, so the channel composer itself can send. The crash is specific to the accessibility button action path.

[dirvine]

Verified the local Swift fix after patching MessagingView.sendMessage(manager:) to stay on the main actor and rebuilding/re-signing /Users/davidirvine/Applications/Communitas-Patched.app.

Evidence from 2026-06-06:

• Invoked the exact Send button accessibility path with System Events: perform action "AXPress" of UI element 15 in the SwiftUI content group.
• AXPress returned successfully instead of crashing.
• Process stayed alive: PID 34080 remained running.
• No new ~/Library/Logs/DiagnosticReports/Communitas*.ips appeared after the test; newest crash report remained Communitas-2026-06-06-011212.ips from before the patch.
• Message rendered locally in codex-private-space-1780701227-37/#general as codex-swift-cliclick-send-after-mainactor-20260606-0144.

This looks fixed for the original AX crash path. Remaining caveat: the Computer Use plugin's set_value/click handle for the patched Swift bundle is still flaky even immediately after get_app_state, so I used System Events for the crash-specific AXPress verification and Computer Use for screen/AX state inspection.