Open Radar

 
=== Environment ===

iOS 17.2.1 (21C66)
Xcode 15.1 (15C65)

Note: It’s reproducible on iOS 17.2.1 (21C66), but I suspect it happens across all iOS 17 builds, since I’ve gotten crash reports coming from 17.1 to 17.3 Beta.

=== Current Behavior ===

Using PhaseAnimator causes a ‘Simultaneous accesses’ crash when killing the app. While force quitting apps is not recommended, users perform this action regularly and it’s causing issues in my app.

=== Expected Behavior ===

The app should not crash upon quitting.

=== Reproduction Steps ===

1. Create a new SwiftUI project
2. Add a PhaseAnimator that doesn't use a trigger.
3. Run the project on an iPhone.
4. Force quit the app from the iPhone’s task manager.
5. Crash.

=== Stack Trace ===

Simultaneous accesses to 0x101705d70, but modification requires exclusive access.
Previous access (a modification) started at SwiftUI`<redacted> + 12108 (0x1b15062cc).
Current access (a read) started at:
0    libswiftCore.dylib                 0x00000001a57cf470 <redacted> + 432
1    libswiftCore.dylib                 0x00000001a57cf688 swift_beginAccess + 84
2    SwiftUI                            0x00000001b1503380 <redacted> + 14364
3    SwiftUI                            0x00000001b16565ac <redacted> + 15408
4    SwiftUI                            0x00000001b089a518 <redacted> + 9464
5    SwiftUI                            0x00000001b089a518 <redacted> + 9148
6    SwiftUI                            0x00000001b17d997c <redacted> + 1944
7    SwiftUI                            0x00000001b08b9870 <redacted> + 44636
8    SwiftUI                            0x00000001b08b9870 <redacted> + 47116
9    libswiftCore.dylib                 0x00000001a57d38dc <redacted> + 56
10   libswiftCore.dylib                 0x00000001a57d4f28 <redacted> + 136
11   SwiftUI                            0x00000001b111fc28 <redacted> + 15256
12   AttributeGraph                     0x00000001d426507c <redacted> + 1236
13   AttributeGraph                     0x00000001d4250c9c <redacted> + 196
14   AttributeGraph                     0x00000001d425f3e4 <redacted> + 352
15   AttributeGraph                     0x00000001d4272c20 AGGraphInvalidate + 36
16   SwiftUI                            0x00000001b1503380 <redacted> + 12156
17   SwiftUI                            0x00000001b16565ac <redacted> + 41600
18   SwiftUI                            0x00000001b16565ac <redacted> + 41340
19   SwiftUI                            0x00000001b16565ac <redacted> + 41648
20   libobjc.A.dylib                    0x00000001a43b9300 <redacted> + 116
21   libobjc.A.dylib                    0x00000001a43b904c objc_destructInstance + 80
22   libobjc.A.dylib                    0x00000001a43b8fec _objc_rootDealloc + 80
23   UIKitCore                          0x00000001ae315234 <redacted> + 124
24   UIKitCore                          0x00000001ae3138ec <redacted> + 1032
25   libobjc.A.dylib                    0x00000001a43b6ab0 <redacted> + 196
26   libobjc.A.dylib                    0x00000001a43b690c objc_autoreleasePoolPop + 260
27   UIKitCore                          0x00000001ae3138ec <redacted> + 1004
28   libobjc.A.dylib                    0x00000001a43b6ab0 <redacted> + 196
29   libobjc.A.dylib                    0x00000001a43b690c objc_autoreleasePoolPop + 260
30   UIKitCore                          0x00000001ae3138ec <redacted> + 1004
31   UIKitCore                          0x00000001af0ccb60 <redacted> + 1124
32   libobjc.A.dylib                    0x00000001a43b6ab0 <redacted> + 196
33   libobjc.A.dylib                    0x00000001a43b690c objc_autoreleasePoolPop + 260
34   UIKitCore                          0x00000001ae340314 <redacted> + 92
35   UIKitCore                          0x00000001ae34009c <redacted> + 164
36   UIKitCore                          0x00000001ae33fe68 <redacted> + 496
37   UIKitCore                          0x00000001ae33fd80 <redacted> + 100
38   UIKitCore                          0x00000001ae33fc98 <redacted> + 72
39   UIKitCore                          0x00000001ae33f790 <redacted> + 84
40   UIKitCore                          0x00000001ae33ee44 <redacted> + 144
41   UIKitCore                          0x00000001ae33ef34 <redacted> + 92
42   CoreFoundation                     0x00000001ac0a1110 <redacted> + 28
43   CoreFoundation                     0x00000001ac0a02f8 <redacted> + 176
44   CoreFoundation                     0x00000001ac09ea68 <redacted> + 340
45   CoreFoundation                     0x00000001ac09d55c <redacted> + 828
46   CoreFoundation                     0x00000001ac09d218 CFRunLoopRunSpecific + 608
47   GraphicsServices                   0x00000001ef61e454 GSEventRunModal + 164
48   UIKitCore                          0x00000001ae4c12b4 <redacted> + 888
49   UIKitCore                          0x00000001ae4c0b14 UIApplicationMain + 340
50   SwiftUI                            0x00000001b0ed125c <redacted> + 604
51   SwiftUI                            0x00000001b0ed125c <redacted> + 160
52   SwiftUI                            0x00000001b0b415fc <redacted> + 2196
53   PhaseAnimatorBug                   0x00000001003f9008 static PhaseAnimatorBugApp.$main() + 40
54   PhaseAnimatorBug                   0x00000001003f91bc main + 12
55   dyld                               0x00000001cedd650c <redacted> + 2240
Message from debugger: Terminated due to signal 9