Hello. I have a mysterious crash that I can't reproduce. The stack traces never have any of my code in them. Here is what I know about the crashes: It doesn't seem to be at all device-specific, but newer devices are far more commonly seen than older devices. It only happens on iOS 14 and up It might possibly be related to airplay (I work on a video player app), because every crash report also has either a thread labeled com.apple.coremedia.displaymirroringobserver or a thread labeled AVAudioSession Notify Thread Here is the stack trace: language Crashed: com.apple.main-thread  EXC_BAD_ACCESS KERN_INVALID_ADDRESS 0x0000000000000020 0 libobjc.A.dylib 0x1bfa07de0 objc_release + 16 1 libsystem_blocks.dylib 0x1f315d784 _Block_release + 188 2 UIKitCore 0x1ae37bf14 -[_UIAfterCACommitBlock run] + 76 3 UIKitCore 0x1adee1984 _runAfterCACommitDeferredBlocks + 296 4 UIKitCore 0x1aded0eb4 _cleanUpAfterCAFlushAndRunDeferredBlocks + 200 5 UIKitCore 0x1adf02484 _afterCACommitHandler + 76 6 CoreFoundation 0x1ab5e687c __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 32 7 CoreFoundation 0x1ab5e0f50 __CFRunLoopDoObservers + 604 8 CoreFoundation 0x1ab5e1498 __CFRunLoopRun + 960 9 CoreFoundation 0x1ab5e0ba0 CFRunLoopRunSpecific + 572 10 GraphicsServices 0x1c2346598 GSEventRunModal + 160 11 UIKitCore 0x1aded22f4 -[UIApplication _run] + 1052 12 UIKitCore 0x1aded7874 UIApplicationMain + 164 13 SpectrumTV 0x1029874d0 main + 29 (SettingsAboutAnalyticsReporter.swift:29) 14 libdyld.dylib 0x1ab2bf568 start + 4 This seems to indicate that we are doing something wrong with a Core Animation completion block. When the OS tries to free the completion blocks, it crashes. But, that still leaves me with a huge search surface area, so I was hoping that by posting here, someone (perhaps someone with knowledge of the code in question) could point me at specifically what causes the above framework code to run. The other option is that someone is corrupting the heap, which is too horrifying to contemplate. 😱

Hello, I am turning to this forum because I suspect I am "doing it wrong" when it comes to implementing VoiceOver accessibility in my collection view. I suspect this because the system has resisted everything I have tried to do, fought it tooth and nail, and I can't see any way to get this to work. The Collection View I have a collection view that displays a large dataset. It uses a custom collection view layout to create a spreadsheet-like view. It has hundreds of rows, and each row can have hundreds of items. The items in each row do not conform to specific column widths. Their width is defined by the data they display, and for the purposes of this discussion, can be considered to be arbitrary. To the left of the "table" is a column of sticky headers whose position remains fixed in relation to the content. On top of the "table" is a row of headers, whose position also remains fixed. The Problem The default accessibility behavior that Apple has baked into UICollectionView is completely impractical for this application. Each row can contain hundreds of items, so a user who is attempting to navigate by swiping right would have to swipe through hundreds of items just to reach the second row (of hundreds). The Desired Behavior I want the user to be able to swipe through just the cells that are onscreen. To scroll, they can use the standard three-finger gesture. When scrolling occurs, VoiceOver should announce the range of data that is being displayed. Attempted Solution 1: Setting the accessibilityElements array I can set the accessibilityElements array of the UICollectionView to only contain the elements that are onscreen. I also can override the accessibilityScroll method to perform the paging upon a three-finger scroll. This works okay, but has some pretty fatal flaws: As the user swipes through elements, the collection view insists upon scrolling horizontally to try and fit the element into view. It also insists upon scrolling vertically to keep the focused element in the middle of the view. This not only causes the content offset to jump around wildly in a disorienting way, but it also brings content into view that VoiceOver does not know about because I have not added it to the accessibilityElements array. A low-vision user, or a user who pans their finger across the screen, would not be able to access those visible elements. VoiceOver refuses to read my paging announcement. No matter when I post a pageScrolled notification, the system will not read it. Setting accessibilityFrame In an attempt to fix the scroll jumping described above, I tried setting the accessibilityFrame of my collection view cells. This did nothing to alter the scroll jumping behavior, and had the added downside that, as the view jumped around, the accessibility frames did not follow it. A bridge too far? Overriding contentOffset I was about to override contentOffset on the collection view so that only I could set it. That would probably work. But it would do nothing to fix the paging announcement. Attempted Solution 2: Ignore the Cells! Use proxy UIAccessibilityElements I tried setting the accessibilityElements array of my collection view to a collection of UIAccessibilityElement instances whose accessibilityFrame matched the frame of the cells they represent. This worked pretty well! No more scrolling nonsense when swiping through cells, and my paging announcements were being read. This approach has a different, equally fatal flaw: If the user attempts to three finger-scroll too quickly, the VoiceOver process will become confused. It acts as though the last selected element is the only element that exists; swiping right or left does nothing. Three finger-scrolling also does nothing. As best as I can tell, it gets stuck with the last selected element as the only one it knows about. I have since replaced all of the elements in the collection view's accessibilityElements array and posted a layoutDidChange notification, which VoiceOver ignores completely. The only way out of this state is to tap on a cell, causing VoiceOver to refresh its collection of views that it knows about. I guess? No idea what's happening there. Now what? I'm at a complete and total loss. I'm at my wit's end. It feels like this seemingly simple customization is entirely impossible. Does anyone know what I'm doing wrong? Thanks!

Hello, I am attempting to track down a crash that isn't giving me a lot of information (crash log included below). Here is what I know so far: According to Apple documentation, a crash in objc_msgSend is due to a zombie object. So I have been trying to recreate the crash with zombies enabled, without success. The address of the object being messaged is 0x0000000000000010, a suspect value. It's always 0x10, across thousands of crash reports with slightly differing stack traces and circumstances. That makes me wonder if the runtime is trying to tell me something with that address, but I have been unable to find any documentation to that effect. We have internal analytics that suggest that the crash always happens after the user activates the system PIP video player, and usually also after backgrounding the app. It is also common (though not universal) that the crash occurs after the user has paused the video (and sometimes resumed it). This post is a bit of a Hail Mary; I'm hoping that maybe someone on here will see something I missed, because I have exhausted most of my own avenues of investigation. Many thanks for any help you can provide. 2023-11-30_07-16-00.4347_-0800-ffd5dc1a3d2ca628e1761ccfec5fe79f223d099e.crash