I have a photo editing app which uses a simple Metal Render to display CIFilter output images. It works just fine in Swift 5 but in Swift 6 it crashes on starting the Metal command buffer with an error in the Queue : com.Metal.CompletionQueueDispatch (serial). The crash is occurring before I can debug.. I changed the command buffer to report MTLCommandBufferDescriptorStatus errorOptions = .encoderExecutionStatus. No luck with getting insight into the source of the crash.. Likewise the error is happening before any of the usual Metal debug tools are enabled. The Metal render works just fine in Swift 5 and also works fine with almost all of the Swift Compiler Upcoming feature flags set to Yes. [The "Default Internal Imports" flag is still No. (the number of compile errors with this setting is absolutely scary! but that's another topic) Do you have any suggestions on debugging or ideas on why the Metal library is crashing in Swift 6??? Everything is current release versions and hardware.

The sample code in the Apple documentation found in  PHCloudIdentifier does not compile in xCode 13.2.1. Can the interface for identifier conversion be clarified so that the answer values are more accessible/readable. The values are 'hidden' inside a Result enum It was difficult (for me) to rewrite the sample code because I made the mistake of interpreting the Result type as a tuple. Result type is really an enum. Using the Result type as the return from library.cloudIdentifierMappings(forLocalIdentifiers: ) and .localIdentifierMappings( for: ) puts the actual mapped identifiers inside the the enum where they need additional access via a .stringValue message or an evaluation of an element of the result enum. For others finding the same compile issue, here is a working version of the sample code. This compiles in xCode 13.2.1. func localId2CloudId(localIdentifiers: [String]) -> [String] {         var mappedIdentifiers = [String]()        let library = PHPhotoLibrary.shared()         let iCloudIDs = library.cloudIdentifierMappings(forLocalIdentifiers: localIdentifiers)         for aCloudID in iCloudIDs {           let cloudResult: Result = aCloudID.value             // Result is an enum .. not a tuple             switch cloudResult {                 case .success(let success):                     let newValue = success.stringValue                     mappedIdentifiers.append(newValue)                 case .failure(let failure):                     // do error notify to user                       }         }         return mappedIdentifiers     } ``` swift func func cloudId2LocalId(assetCloudIdentifiers: [PHCloudIdentifier]) -> [String] {             // patterned error handling per documentation         var localIDs = [String]()         let localIdentifiers: [PHCloudIdentifier: Result<String, Error>]  = PHPhotoLibrary.shared() .localIdentifierMappings(                   for: assetCloudIdentifiers)         for cloudIdentifier in assetCloudIdentifiers {             guard let identifierMapping = localIdentifiers[cloudIdentifier] else {                 print("Failed to find a mapping for \(cloudIdentifier).")                 continue             }             switch identifierMapping {                 case .success(let success):                     localIDs.append(success)                 case .failure(let failure) :                     let thisError = failure as? PHPhotosError                     switch thisError?.code {                         case .identifierNotFound:                             // Skip the missing or deleted assets.                             print("Failed to find the local identifier for \(cloudIdentifier). \(String(describing: thisError?.localizedDescription)))")                         case .multipleIdentifiersFound:                             // Prompt the user to resolve the cloud identifier that matched multiple assets.                             print("Found multiple local identifiers for \(cloudIdentifier). \(String(describing: thisError?.localizedDescription))") //                            if let selectedLocalIdentifier = promptUserForPotentialReplacement(with: thisError.userInfo[PHLocalIdentifiersErrorKey]) { //                                localIDs.append(selectedLocalIdentifier)                         default:                             print("Encountered an unexpected error looking up the local identifier for \(cloudIdentifier). \(String(describing: thisError?.localizedDescription))")                     }               }             }         return localIDs     }

In an iOS viewController, I use the NSDiffableDataSource to populate a tableView from the results of a CoreData fetchController. The result class is defined by CoreData - in this case a class named CDFilterStack. In xCode 16.0 Beta with strict concurrency checking = 'Complete' the CDFilterStack class has this warning everywhere it is referenced. "Type 'CDFilterStack' does not conform to the 'Sendable' protocol; this is an error in the Swift 6 language mode." The class definition of CDFilterStack is not editable because it is generated by CoreData. I think I need to mark this class (and other similar classes) as @preconcurrency... but how & where? Here's one method sample that generates three of these warnings func initialSnapShot() -> NSDiffableDataSourceSnapshot<Int, CDFilterStack> { var snapshot = NSDiffableDataSourceSnapshot<Int, CDFilterStack>() if let sections = dataProvider.fetchedResultsController.sections { for index in 0..<sections.count { let thisSection = sections[index] guard let sectionStacks = thisSection.objects as? [CDFilterStack] else { continue} snapshot.appendSections([index]) snapshot.appendItems(sectionStacks) } // for loop that will continue on error in objects } return snapshot } Careful reading of the various migration guides hasn't produced an example of how to handle this.. (btw the migration guides are nicely done:)

In the case where an app uses the Photo Library to reload images by using a fetchRequest with localIdentifier there is hole in the following guidance in WWDC21 "Improve access to Photos in your app" "When the picker session is completed, selected photos will be returned to your app. Suppose the configuration is initialized with a PHPhotoLibrary object, picker results will contain both item providers and asset identifiers. Your app can use the item provider to load and display selected photos." The picker result providers do not load the image if the image is not in the limited library list, even though the user has selected them with the PHPicker. It looks like the workaround is to raise a user error that the image is not loaded because it is not in the limited selection, then do the PHPhotoLibrary.shared().presentLimitedLibraryPicker so the limited selection is the way the user wants it. This workaround seems like an awful thing to do to the user since they have to pick the same photo(s) twice.. Also - this scenario works fine with the PHPickerDemo because privacy setting for the demo is not added in settings.. Presumably because PHPickerDemo is not directly using the PhotoKit API methods. Any thoughts or workaround alternatives that you see? Or raise a bug? Thanks!!

Sometimes the log has this cryptic message. Any ideas on what action is needed, or how to implement the 'should have cancelled validation' that is referenced in the message? "[Assert] Somehow we ended up in _validateCurrentFocusedItemForAppearingEnvironment even though there is no focused item. We should have cancelled the validation request in that case."

My new iMac is rebooting about half way into the installing phase of xCode 13. Many attempts.. always the same crash A Feedback Assistant bug report has been filled. I can restore the last version of xCode from backup Any ideas for a work around? Obviously no new app releases from me until xCode is running again at the 13 version

iOS 13 introduced CIFilter "CIKMeans" which is used by the related CIPaletteCentroid  and CIPalettize filters. Are there any examples of the use of CIKMeans? I am mystified by the CIKMeans error "Mean seeds should be passed as a K x 1 image.." I am using a CIImage as the input for the inputMeans parm. The inputMeans attribute has this in the parmDictionary   ▿ 3 elements  ▿ 0 : 2 elements   - key : "CIAttributeDescription"   - value : Specifies the color seeds to use for k-means clustering, either passed as an image or an array of colors.  ▿ 1 : 2 elements   - key : "CIAttributeClass"   - value : CIImage  ▿ 2 : 2 elements   - key : "CIAttributeDisplayName"   - value : Means" What is a CIImage that qualifies as a "K x 1" image?