The Apple documentation for [UIViewController willMoveToParentViewController:] states, Called just before the view controller is added or removed from a container view controller. Hence, the view controller being popped should appear at the top of the navStack when willMoveToParentViewController: is called. In iPadOS 16 and 17 the view controller being popped appears at the top of the navStack when willMoveToParentViewController: is called. In iPadOS 18 the view controller being popped has already been (incorrectly) removed from the navStack. We confirmed this bug using iPadOS 18.2 as well as 18.0. Our app relies upon the contents of the navStack within willMoveToParentViewController: to track the user's location within a folder hierarchy. Our app works smoothly on iPadOS 16 and 17. Conversely, our customers running iPadOS 18 have lost client data and corrupted their data folders as a result of this bug! These customers are angry -- not surprisingly, some have asked for refunds and submitted negative app reviews. Why doesn't willMoveToParentViewController: provide the correct navStack in iPadOS 18.2?

We're trying to implement a backup/restore data feature in our business productivity iPad app using UIDocumentPickerViewController and AppleArchive, but discovered AppleArchive crashes instead of failing gracefully when decrypting a corrupt archive. As described in forum post 765101, UIDocumentPickerViewController can handoff a corrupt copy of an archive to UIDocumentPickerDelegate under specific circumstances. We've duplicated this behavior with iPadOS 16.6.1 and 17.7 when building our app with Xcode 15.4 targeting minimum deployment of iPadOS 16. We haven't tested this with the bleeding edge iPadOS 18. Our app is primarily Objective-C, but it utilizes the Swift-based AppleArchive 'EncryptingAndDecryptingDirectories' sample code associated with WWDC21 session: 10233: Bring Encrypted Archives and Performance Improvements to Your App with Accelerate. The WWDC21 'EncryptingAndDecryptingDirectories' Swift sample project crashes in a similar manner when a corrupt archive file created by UIDocumentPickerViewController is dropped into the sample app's window for decryption (see attached crash log). Does anyone know if there's a workaround for the 'EncryptingAndDecryptingDirectories' sample project to prevent AppleArchive from crashing when decrypting a corrupt archive? crash log.txt

We're trying to implement a backup/restore data feature in our business productivity iPad app using UIDocumentPickerViewController and AppleArchive, but discovered odd behavior of [UIDocumentPickerViewController initForOpeningContentTypes: asCopy:YES] when reading large archive files from a USB drive. We've duplicated this behavior with iPadOS 16.6.1 and 17.7 when building our app with Xcode 15.4 targeting minimum deployment of iPadOS 16. We haven't tested this with bleeding edge iPadOS 18. Here's our Objective-C code which presents the picker: NSArray* contentTypeArray = @[UTTypeAppleArchive]; UIDocumentPickerViewController* docPickerVC = [[UIDocumentPickerViewController alloc] initForOpeningContentTypes:contentTypeArray asCopy:YES]; docPickerVC.delegate = self; docPickerVC.allowsMultipleSelection = NO; docPickerVC.shouldShowFileExtensions = YES; docPickerVC.modalPresentationStyle = UIModalPresentationPopover; docPickerVC.popoverPresentationController.sourceView = self.view; [self presentViewController:docPickerVC animated:YES completion:nil]; The UIDocumentPickerViewController remains visible until the selected external archive file has been copied from the USB drive to the app's local tmp sandbox. This may take several seconds due to the slow access speed of the USB drive. During this time the UIDocumentPickerViewController does NOT disable its tableview rows displaying files found on the USB drive. Even the most patient user will tap the desired filename a second (or third or fourth) time since the user's initial tap appears to have been ignored by UIDocumentPickerViewController, which lacks sufficient UI feedback showing it's busy copying the selected file. When the user taps the file a second time, UIDocumentPickerViewController apparently begins to copy the archive file once again. The end result is a truncated copy of the selected file based on the time between taps. For instance, a 788 MB source archive may be copied as a 56 MB file. Here, the UIDocumentPickerDelegate receives a 56 MB file instead of the original 788 MB of data. Not surprisingly, AppleArchive fails to decrypt the local copy of the archive because it's missing data. Instead of failing gracefully, AppleArchive crashes in AAArchiveStreamClose() (see forums post 765102 for details). Does anyone know if there's a workaround for this strange behavior of UIDocumentPickerViewController?