So I've been developing happily with CoreData+CloudKit for a while now, and really haven't run into any issues until this. I've migrated my model a couple of times, and it worked fine, but this was the first time I added a new entity to the model. If I run on a device (any device, iPhone, iPad, Mac via Catalyst), I get a migration error. Here's the entirety of my persistentContainer setup: public var persistentContainer: NSPersistentContainer = { let modelPath = Bundle(for: CoreDataStack.self).url(forResource: "Progress", withExtension: "momd")! let model = NSManagedObjectModel(contentsOf: modelPath)! let container = NSPersistentCloudKitContainer(name: "Progress", managedObjectModel: model) container.loadPersistentStores(completionHandler: { (storeDescription, error) in if let error = error as NSError? { print(storeDescription) fatalError("Unresolved error \(error), \(error.userInfo)") } }) return container }()And here's the error I'm getting:Callstacks=true}}}CoreData: annotation: : Attempting recovery from error encountered during addPersistentStore: Error Domain=NSCocoaErrorDomain Code=134110 "An error occurred during persistent store migration." UserInfo={sourceURL=[…].sqlite, reason=Cannot migrate store in-place: constraint violation during attempted migration, destinationURL=[…].sqlite, NSUnderlyingError=0x600000cebae0 {Error Domain=NSCocoaErrorDomain Code=134111 "(null)" UserInfo={_NSCoreDataOptimisticLockingFailureConflictsKey=( ), NSUnderlyingException=Constraint unique violation, reason=constraint violation during attempted migration, NSExceptionOmitCallstacks=true}}}Important note: I am not using contraints at all in this model. I have created a new Entity, given it a single attribute, and a single one-to-many relationship with an existing entity. That's all.Also, here's an excerpt from the logs when I have -com.apple.CoreData.MigrationDebug enabled, pointing to an issue with the CloudKit metadata tables update step:CoreData: annotation: Completed persistent history metadata tables update CoreData: annotation: Beginning CloudKit metadata tables update CoreData: annotation: Failed lightweight migration on connection CoreData: annotation: Rolling back formal transactionAnyone seen this, have any idea what could be failing, or how to make cloudkit/coredata happy with a migration like this?

I have a class with a parameter in the form class class_name: Codable { var array_name = [] } Running the code, I see I can add numbers in the array. But when I get the array in another function it says it is empty. I do it with: let new_class = class_name() Can it happen that the value gets reseted for calling the class again?

Anyone have a really good YouTube tutorial on how to implement an image as binary data in core data? Thanks!

We're seeing a rare issue in the field that I haven't been able to reproduce. The app primarily uses a main queue managed object context, with a couple of other private queue contexts for specialized cases. Those cases do not modify objects that are also modified in the main queue context, so we haven't done anything to specifically handle merge conflicts. We shouldn't have any during normal operation.In at least one case, a user transitions from background to foreground and back to background in a short period of time. One of the things we do when transitioning to inactive state is to save the main queue context. During this save, sometimes it appears that all of the objects loaded in the main queue context will become conflicted. When this happens, the conflicts are very odd:Failed to save: Error Domain=NSCocoaErrorDomain Code=133020 "Could not merge changes." UserInfo={conflictList=( "NSMergeConflict (0x11d8ec540) for NSManagedObject (0x11bf50990) with objectID '0xd00000000f340014 <x-coredata://36EBC17F-A244-4CE0-BB10-C0C5C2C3AFC1/Document/p973>' with oldVersion = 0 and newVersion = 4 and old object snapshot = { ... all attributes are null ... } and new cached row = { ... all attributes have the expected values ... }"I've encountered merge conflicts in the past, and they're due to modifications made in two contexts simultaneously. Here, we aren't modifying simultaneously, the oldVersion value is 0 and the old object snapshot is an empty object (none of the attributes are set to a value).Has anyone else seen this behavior? Is there an explanation for how an object could have an oldVersion = 0?Also, the docs don't provide quite enough detail for me to understand the difference between an "object snapshot" and a "cached row".

So I have an entity in my core data model called recipe. I need to create another entity containing a recipe and a date that the recipe is assigned to. Can I do this similar to the way I've done it in the image and just save a Recipe object in the initialization of PlannedRecipe object in the Persistence file? Basically I just need to know how to add a entity in an entity using this core data model and persistence file. Persistence file: import CoreData struct PersistenceController {     static let shared = PersistenceController()     let container: NSPersistentCloudKitContainer     init(inMemory: Bool = false) {         container = NSPersistentCloudKitContainer(name: "ReciPrep")         if inMemory {             container.persistentStoreDescriptions.first!.url = URL(fileURLWithPath: "/dev/null")         }         container.loadPersistentStores(completionHandler: { (storeDescription, error) in             if let error = error as NSError? {                 fatalError("Unresolved error \(error), \(error.userInfo)")             }         })         container.viewContext.automaticallyMergesChangesFromParent = true     }     func addPlannedRecipe(recipe: Recipe,date: Date, context: NSManagedObjectContext){         let plannedRecipe = PlannedRecipe(context: context)         plannedRecipe.id = UUID()         plannedRecipe.date = Date()         plannedRecipe.recipe = recipe //Giving me an error: "Cannot assign value of type 'Recipe' to type 'Data?'"                  save(context: context)     }          func save(context: NSManagedObjectContext){         do {             try context.save()         } catch {             let nsError = error as NSError             fatalError("Unresolved error \(nsError), \(nsError.userInfo)")         }     } } I guess this problem can be solved if I can convert a recipe into binary data or some other savable data in an entity. Any help would be greatly appreciated.

So I have a core data entity titled recipe. I'm trying to make a search bar to search the list of recipes and my method of doing so is doing a fetch request of all objects and converting it to an array of those objects and then filtering the array and displaying the results. Any idea as to how to convert a type fetch results to an array? PS: as I'm typing this it occurred to me I could just do a for each loop and add them to the array as I go, but is there a quicker way to do this? Like a function? Thanks!!!

Any insights on how to incorporate CloudKit (or CoreData) in the WidgetKit extension? Where in the WidgetKit api do I make the asynchronous call to load the data to be available for the TimelineProvider?

I was wondering whether objects in Core Data (and CloudKit) conform, or are able to be conformed, to the Transferable protocol. As far as I can see there is no underlying implementation yet, but maybe this will be added as a future feature so that SwiftUI and Core Data can work better together. In the WWDC22 session "Enhance collaboration experiences with Messages" at 10:21, a struct call Note was implementing the transferRepresentation required property and returned an object of type CKShareTransferRepresentation from its body. I couldn't find any reference to this type anywhere in the documentation and nothing else was mentioned in the session video. Maybe this is something that is going to be added soon or was removed after the video was made. Since I want to use Core Data in my SwiftUI app and want to enable sharing features, such as collaboration via the shared database, NSManagedObject subclasses need some way of conforming to the Transferable protocol. I was hoping there would be a specialised way to do this, and the aforementioned type from the session video sort of hinted at this. I am just asking here to see if anyone has any information about this – whether this feature is about to be released, how this issue can be solved, or another way to do this. Any help is appreciated.

Hello:I have been struggling with this small piece of code foe days. Every time I resolve one problem with it, another one pops up:I seem to have resolved the problem of "Expected Pattern" but now I have the problem "Cannot call value of non-function type '[String]'Here is the code:var name = [String]() override func viewDidLoad() { super.viewDidLoad() let persistentContainer = NSPersistentContainer(name: "No_Regrets") persistentContainer.loadPersistentStores { (_, error) in if let error = error { fatalError("Failed to load Core Data stack: \(error)") } } // Creates a task with a new background context created on the fly persistentContainer.performBackgroundTask { (context) in //iterates the array let Gains = [self.gain1, self.gain2, self.gain3, self.gain4] Gains.forEach {_ in // Creates a new entry inside the context `context` and assign the array element `name` to the dog's name let gain1 = Gains(context: context) //Cannot call value of non-function type '[String]' gain1.name = name let gain2 = Gains(context: context) //Cannot call value of non-function type '[String]' gain2.name = name let gain3 = Gains(context: context) //Cannot call value of non-function type '[String]' gain3.name = name let gain4 = Gains(context: context) //Cannot call value of non-function type '[String]' gain4.name = name } do { // Saves the entries created in the `forEach` try context.save() } catch { fatalError("Failure to save context: \(error)") } }

Hi I put CoreData objects from one to many relationship in ForEach List and when I delete one item all objects from the List disappear. They come back after the view is reload.             List{                 ForEach(viewModel.allPayments){payment in                     Text("(payment.amount)")                 }                 .onDelete { indexSet in                     viewModel.delete(at: indexSet)                 }             }             .listStyle(.plain) final class PaymentViewModel:ObservableObject{     @Published var allPayments:[Payment] = []     @Published var isNavigationLinkActive = false     var loan: Loan     init(loan: Loan) {         self.loan = loan     }          func fetchAllPayments(){         allPayments = PersistanceController.shared.fetchPayments(loan: loan)     }          func delete(at indexSet:IndexSet){         guard let indeRow = indexSet.first else {return}         PersistanceController.shared.delete(object: allPayments[indeRow])         PersistanceController.shared.save()     } } import CoreData struct PersistanceController{     static let shared = PersistanceController()     let container = NSPersistentContainer(name: "Stash")     init(){         container.loadPersistentStores { description, error in             if let error = error {                 print("Core Data loading error. (error.localizedDescription)")             }         }     }     var viewContext: NSManagedObjectContext{         return container.viewContext     }          func save(){         do{             try viewContext.save()         }catch{             print("Core Data saving error. (error.localizedDescription)")         }     }          func delete(object:NSManagedObject){         viewContext.delete(object)         save()     }          func fetchPayments(loan:Loan)->[Payment]{         let request:NSFetchRequest = Payment.fetchRequest()         request.predicate = NSPredicate(format: "loan == %@", loan)         request.sortDescriptors = [NSSortDescriptor(keyPath: \Payment.date, ascending: true)]         do{            return try viewContext.fetch(request)         }catch{             print("Unable to fetchPayments")             return []         }     } } Is there any way to delete object from Core Data in ForEach List without disappearing all object from the list?

I have the model that the images show. In the entity Word I have the attribute name, that I want to be constraint. If I don't make it constraint the model works perfectly, but when I make it constraint it crashes just when opening giving this error. The only code it reads is a DataController in which I just create the container and set mergePolicy to NSmergeByPropertyObjectTrumpMergePolicy. I think I need name in Word to be constraint. Otherwise when deleting or adding relations with train_list or test_list I get many words with the same name, when I just want one that is added or deleted from these lists. I don't really know what are the requirements to use a constraint. Maybe there is a conflict with the relationships I have or the delete rules. Any idea?

I want to add Core Data/CloudKit data persistence to my app. Currently my app only uses local on device @AppStorage. Looking for best approach to bring in @FetchRequest functionality for my views, and tie my model data into Core Data and CloudKit.  In my app currently (without Core Data) my content view has an instance of my view model (separate file) accessed using an Environment Object. I use local @AppStorage persistence. See below for my Current app architecture: In my lab this week, i got suggestions that I can modify my app structure to incorporate Core Data + CloudKit. Would the following structure work?:

I have a simple SwiftUI application with CoreData and two views. One view displays all "Place" objects. You can create new places and you can show the details for the place. Inside the second view you can add "PlaceItem"s to a place. The problem is that, once a new "PlaceItem" is added to the viewContext, the @NSFetchRequest seems to forget about its additional predicates, which I set in onAppear. Then every place item is shown inside the details view. Once I update the predicate manually (the refresh button), only the items from the selected place are visible again. Any idea how this can be fixed? Here's the code for my two views: struct PlaceView: View { @FetchRequest(sortDescriptors: []) private var places: FetchedResults<Place> @Environment(\.managedObjectContext) private var viewContext var body: some View { NavigationView { List(places) { place in NavigationLink { PlaceItemsView(place: place) } label: { Text(place.name ?? "") } } } .toolbar { ToolbarItem(placement: .primaryAction) { Button { let place = Place(context: viewContext) place.name = NSUUID().uuidString try! viewContext.save() } label: { Label("Add", systemImage: "plus") } } } .navigationTitle("Places") } } struct PlaceItemsView: View { @ObservedObject var place: Place @FetchRequest(sortDescriptors: []) private var items: FetchedResults<PlaceItem> @Environment(\.managedObjectContext) private var viewContext func updatePredicate() { items.nsPredicate = NSPredicate(format: "place == %@", place) } var body: some View { NavigationView { List(items) { item in Text(item.name ?? ""); } } .onAppear(perform: updatePredicate) .toolbar { ToolbarItem(placement: .primaryAction) { Button { let item = PlaceItem(context: viewContext) item.place = place item.name = NSUUID().uuidString try! viewContext.save() } label: { Label("Add", systemImage: "plus") } } ToolbarItem(placement: .navigationBarLeading) { Button(action: updatePredicate) { Label("Refresh", systemImage: "arrow.clockwise") } } } .navigationTitle(place.name ?? "") } } struct ContentView: View { @Environment(\.managedObjectContext) private var viewContext var body: some View { NavigationView { PlaceView() } } } Thanks!

I use NSPersistentCloudKitContainer to synchronize data between iOS and macOS. After installing the app, it takes long (sometimes up to an hour) for all data to become available. Related to this, I have a few questions: Synchronization seems only to take place when the app runs in the foreground. Is there a way to keep the app synchronizing when it is brought to the background? I have enabled remote notifications and use registerForRemoteNotifications in my app delegate (via UIApplicationDelegateAdaptor). I haven't yet experimented with background processing. Should I do that, and can you point me to some references? Is there a way to check whether the local-stored data matches what's available on the server? E.g. checking whether a (local-stored) NSPersistentHistoryToken matches the latest NSPersistentHistoryToken on the server. Internally NSPersistentCloudKitContainer knows, as I can see log events popping up saying that there are no new data to mirror. I would like to know this to inform the user that synchronization still takes place. Currently, users are complaining about missing data, which is just not available yet. Thanks!

I am sharing my CoreData model between my iOS main app target and a new Share Extension target like this post:  This is working well for the most part except for one thing.  NSFetchedResultsController is not returning results when called from the Shared Extension. What is strange though is that if I do a plain NSFetchRequest in my Share Extension, I do get CoreData results returned that were originally saved from the main app...so I think Container setup as well as model must be being shared correctly via AppContainer. NSFetchedResultsControllerDelegate controllerDidChangeContent is never called. Any ideas or suggestions? import UIKit import MobileCoreServices class ShareViewController: UIViewController { private(set) lazy var resultsController: NSFetchedResultsController<Person> = createFetchedResultsController() override func viewDidLoad() { super.viewDidLoad() let fetchRequest = NSFetchRequest<Person>(entityName: "Person") fetchRequest.sortDescriptors = [NSSortDescriptor(key: "date", ascending: false)] do { /// this works! let persons = try CoreDataManager.shared.managedObjectContext.fetch(fetchRequest) print("Got \(persons.count) Persons") } catch { print("Fetch failed") } activateResultsController() } func createFetchedResultsController() -> NSFetchedResultsController<Person> { CoreDataManager.shared.container.viewContext.stalenessInterval = 0 CoreDataManager.shared.container.viewContext.refreshAllObjects() CoreDataManager.shared.container.viewContext.stalenessInterval = -1 let fetchRequest = NSFetchRequest<Person>(entityName: "Person") fetchRequest.sortDescriptors = [NSSortDescriptor(key: "date", ascending: false)] ////managedObjectContext: CoreDataManager.shared.managedObjectContext, let controller = NSFetchedResultsController( fetchRequest: fetchRequest, managedObjectContext: CoreDataManager.shared.managedObjectContext, sectionNameKeyPath: nil, cacheName: nil ) controller.delegate = self return controller } private func activateResultsController() { do { try resultsController.performFetch() } catch { fatalError("Failed to fetch entities: \(error)") } } } // MARK: - Results Controller Delegate extension ShareViewController: NSFetchedResultsControllerDelegate { func controllerDidChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) { guard let sections = resultsController.sections else { return } let section = sections[0] let rows = section.numberOfObjects print("rows=\(rows)") } } import UIKit import CoreData class CoreDataManager { static let shared = CoreDataManager() internal var container: NSPersistentContainer var managedObjectContext: NSManagedObjectContext { container.viewContext } init() { container = NSPersistentContainer(name: Constants.name) guard let storeDirectory = FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask).first else { // We'll throw a fatalError() because we can't really proceed without storeDirectory fatalError(file: "Could not find .applicationSupportDirectory - exiting") } let storeURL = storeURL(for: "group.mygroup.testshareextensioncoredata", databaseName: "\(Constants.name)") let storeDescription = NSPersistentStoreDescription(url: storeURL) container.persistentStoreDescriptions = [storeDescription] container.loadPersistentStores(completionHandler: { storeDescription, error in if let error = error as NSError? { // We'll throw a fatalError() because we can't really proceed without loading the PersistentStore fatalError("loadPersistentStore failed \(error), \(error.userInfo)") } }) } // MARK: - Core Data Saving support func saveContext() { managedObjectContext.performAndWait { if managedObjectContext.hasChanges { do { try managedObjectContext.save() } catch { } } } } /// Returns a URL for the given app group and database pointing to the sqlite database. func storeURL(for appGroup: String, databaseName: String) -> URL { guard let fileContainer = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: appGroup) else { fatalError("Shared file container could not be created.") } return fileContainer.appendingPathComponent("\(databaseName).sqlite") } } internal extension CoreDataManager { enum Constants { static let name = "ShareExtensionCoreDataTest" } }

I am trying to implement a search bar in my recipe storage app. I got recommended using the .filter function that I didn’t know could be used on FetchedResults. So I did and now I’m getting errors, but not ones saying that it isn’t in the scope so I believe this is possible, just now sure how. The ForEach loop containing the filter: •ForEach(recipes.filter({$0.title.contains(searchingFor)})) { recipe in Note: Recipes is just a FetchedResults type and searchingFor is just a string that comes from the search bar. The errors: •Value of optional type 'String?' must be unwrapped to refer to member 'contains' of wrapped base type 'String' •Chain the optional using '?' to access member 'contains' only for non-'nil' base values •Force-unwrap using '!' to abort execution if the optional value contains 'nil' Any help is greatly appreciated.

Dear community, I am an indie developer and daily new to iOS development. I have created my first app some time ago - mainly based on Swift/SwiftUI and some Apple technologies such as Core Data. So far I have luckily been spared from severe bugs but recently I have noticed a weird crash being reported via Xcode from production users that I just cannot interpret. According to the Xcode Organizer it seems somehow to be connected to Core Data (more specifically .loadPersistentStores). I would very much appreciate any help, hints or solutions that you might have or insights from similar crashes/situations. The crash has so far occurred on multiple devices and app versions - the only constant seems to be that all devices that produced the crash were running iOS15. Unfortunately I was not able to recreate it in the simulator or on a physical device. Attached you can find an exemplary crash report (some redacted parts with "***"). Exemplary crash report Thanks in advance!