I’m seeing a crash in production for a small percentage of users, and have narrowed it down based on logging to happening as or very shortly after an alert is presented using SwiftUI.
This seems to be isolated to iOS 17.5.1, but since it’s a low-volume crash I can’t be sure there aren’t other affected versions. What can I understand from the crash report?
Here’s a simplified version of the code which presents the alert, which seems so simple I can’t understand why it would crash. And following that is the crash trace.
// View (simplified)
@MainActor public struct MyView: View {
@ObservedObject var model: MyViewModel
public init(model: MyViewModel) {
self.model = model
}
public var body: some View {
myViewContent
.overlay(clearAlert)
}
var clearAlert: some View {
EmptyView().alert(
"Are You Sure?",
isPresented: $model.isClearAlertVisible,
actions: {
Button("Keep", role: .cancel) { model.clearAlertKeepButtonWasPressed() }
Button("Delete", role: .destructive) { model.clearAlertDeleteButtonWasPressed() }
},
message: {
Text("This cannot be undone.")
}
)
}
}
// Model (simplified)
@MainActor public final class MyViewModel: ObservableObject {
@Published var isClearAlertVisible = false
func clearButtonWasPressed() {
isClearAlertVisible = true
}
func clearAlertKeepButtonWasPressed() {
// No-op.
}
func clearAlertDeleteButtonWasPressed() {
// Calls other code.
}
}
Incident Identifier: 36D05FF3-C64E-4327-8589-D8951C8BAFC4
Distributor ID: com.apple.AppStore
Hardware Model: iPhone13,2
Process: My App [379]
Path: /private/var/containers/Bundle/Application/B589E780-96B2-4A5F-8FCD-8B34F2024595/My App.app/My App
Identifier: com.me.MyApp
Version: 1.0 (1)
AppStoreTools: 15F31e
AppVariant: 1:iPhone13,2:15
Code Type: ARM-64 (Native)
Role: Foreground
Parent Process: launchd [1]
Coalition: com.me.MyApp [583]
Date/Time: 2024-06-21 20:09:20.9767 -0500
Launch Time: 2024-06-20 18:41:01.7542 -0500
OS Version: iPhone OS 17.5.1 (21F90)
Release Type: User
Baseband Version: 4.50.06
Report Version: 104
Exception Type: EXC_BREAKPOINT (SIGTRAP)
Exception Codes: 0x0000000000000001, 0x00000001a69998c0
Termination Reason: SIGNAL 5 Trace/BPT trap: 5
Terminating Process: exc handler [379]
Triggered by Thread: 0
Kernel Triage:
VM - (arg = 0x3) mach_vm_allocate_kernel failed within call to vm_map_enter
VM - (arg = 0x3) mach_vm_allocate_kernel failed within call to vm_map_enter
VM - (arg = 0x3) mach_vm_allocate_kernel failed within call to vm_map_enter
VM - (arg = 0x3) mach_vm_allocate_kernel failed within call to vm_map_enter
VM - (arg = 0x3) mach_vm_allocate_kernel failed within call to vm_map_enter
Thread 0 name:
Thread 0 Crashed:
0 libswiftCore.dylib 0x00000001a69998c0 _assertionFailure(_:_:file:line:flags:) + 264 (AssertCommon.swift:144)
1 AttributeGraph 0x00000001d0cd61a4 Attribute.init<A>(body:value:flags:update:) + 352 (Attribute.swift:473)
2 SwiftUI 0x00000001ac034054 closure #1 in Attribute.init<A>(_:) + 128 (<compiler-generated>:0)
3 SwiftUI 0x00000001ac033cac partial apply for closure #1 in Attribute.init<A>(_:) + 32 (<compiler-generated>:0)
4 libswiftCore.dylib 0x00000001a6ad0450 withUnsafePointer<A, B>(to:_:) + 28 (LifetimeManager.swift:128)
5 SwiftUI 0x00000001ad624d14 closure #2 in UIKitDialogBridge.startTrackingUpdates(actions:) + 268 (UIKitDialogBridge.swift:370)
6 SwiftUI 0x00000001ad624ae0 UIKitDialogBridge.startTrackingUpdates(actions:) + 248 (UIKitDialogBridge.swift:369)
7 SwiftUI 0x00000001ad6250cc closure #4 in UIKitDialogBridge.showNewAlert(_:id:) + 72 (UIKitDialogBridge.swift:471)
8 SwiftUI 0x00000001abfdd050 thunk for @escaping @callee_guaranteed () -> () + 36 (:-1)
9 UIKitCore 0x00000001aa5722e4 -[UIPresentationController transitionDidFinish:] + 1096 (UIPresentationController.m:651)
10 UIKitCore 0x00000001aa571d88 __56-[UIPresentationController runTransitionForCurrentState]_block_invoke.114 + 320 (UIPresentationController.m:1390)
11 UIKitCore 0x00000001aa5cb9ac -[_UIViewControllerTransitionContext completeTransition:] + 116 (UIViewControllerTransitioning.m:304)
12 UIKitCore 0x00000001aa34a91c __UIVIEW_IS_EXECUTING_ANIMATION_COMPLETION_BLOCK__ + 36 (UIView.m:16396)
13 UIKitCore 0x00000001aa34a800 -[UIViewAnimationBlockDelegate _didEndBlockAnimation:finished:context:] + 624 (UIView.m:16429)
14 UIKitCore 0x00000001aa349518 -[UIViewAnimationState sendDelegateAnimationDidStop:finished:] + 436 (UIView.m:0)
15 UIKitCore 0x00000001aa356b14 -[UIViewAnimationState animationDidStop:finished:] + 192 (UIView.m:2400)
16 UIKitCore 0x00000001aa356b84 -[UIViewAnimationState animationDidStop:finished:] + 304 (UIView.m:2422)
17 QuartzCore 0x00000001a96f8c50 run_animation_callbacks(void*) + 132 (CALayer.mm:7714)
18 libdispatch.dylib 0x00000001aff61dd4 _dispatch_client_callout + 20 (object.m:576)
19 libdispatch.dylib 0x00000001aff705a4 _dispatch_main_queue_drain + 988 (queue.c:7898)
20 libdispatch.dylib 0x00000001aff701b8 _dispatch_main_queue_callback_4CF + 44 (queue.c:8058)
21 CoreFoundation 0x00000001a808f710 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 16 (CFRunLoop.c:1780)
22 CoreFoundation 0x00000001a808c914 __CFRunLoopRun + 1996 (CFRunLoop.c:3149)
23 CoreFoundation 0x00000001a808bcd8 CFRunLoopRunSpecific + 608 (CFRunLoop.c:3420)
24 GraphicsServices 0x00000001ecf3c1a8 GSEventRunModal + 164 (GSEvent.c:2196)
25 UIKitCore 0x00000001aa6c490c -[UIApplication _run] + 888 (UIApplication.m:3713)
26 UIKitCore 0x00000001aa7789d0 UIApplicationMain + 340 (UIApplication.m:5303)
27 SwiftUI 0x00000001ac27c148 closure #1 in KitRendererCommon(_:) + 168 (UIKitApp.swift:51)
28 SwiftUI 0x00000001ac228714 runApp<A>(_:) + 152 (UIKitApp.swift:14)
29 SwiftUI 0x00000001ac2344d0 static App.main() + 132 (App.swift:114)
30 My App 0x00000001001e7bfc static MyApp.$main() + 52 (MyApp.swift:0)
31 My App 0x00000001001e7bfc main + 64
32 dyld 0x00000001cb73de4c start + 2240 (dyldMain.cpp:1298)