struct ModelContainerSetup { static let shared = ModelContainerSetup() private static let containerIdentifier = "iCloud.Journal" func setupModelContainer() -> ModelContainer { let schema = Schema([User.self]) let modelConfiguration = ModelConfiguration( schema: schema, isStoredInMemoryOnly: false, cloudKitDatabase: .private(Self.containerIdentifier) ) do { return try ModelContainer(for: schema, configurations: [modelConfiguration]) } catch { fatalError("Could not create ModelContainer: \(error)") } } **Expected Behavior: ** When CloudKit storage is full, the app should continue functioning with local storage Data should persist locally even if cloud sync fails Sync should resume when storage becomes available **Actual Behavior: ** ModelContainer initialization fails completely Local data also stops getting saved **Environment: ** iOS 17.0+ SwiftData Private CloudKit database Ideal Behaviour: When iCloud fails, the data should still be saved locally. I do not want to have two different containers so that I can maintain data consistency.

I created 2 different schemas, and made a small change to one of them. I added a property to the model called "version". To see if the migration went through, I setup the migration plan to set version to "1.1.0" in willMigrate. In the didMigrate, I looped through the new version of Tags to check if version was set, and if not, set it. I did this incase the willMigrate didn't do what it was supposed to. The app built and ran successfully, but version was not set in the Tag I created in the app. Here's the migration: enum MigrationPlanV2: SchemaMigrationPlan { static var schemas: [any VersionedSchema.Type] { [DataSchemaV1.self, DataSchemaV2.self] } static let stage1 = MigrationStage.custom( fromVersion: DataSchemaV1.self, toVersion: DataSchemaV2.self, willMigrate: { context in let oldTags = try? context.fetch(FetchDescriptor<DataSchemaV1.Tag>()) for old in oldTags ?? [] { let new = Tag(name: old.name, version: "Version 1.1.0") context.delete(old) context.insert(new) } try? context.save() }, didMigrate: { context in let newTags = try? context.fetch(FetchDescriptor<DataSchemaV2.Tag>()) for tag in newTags ?? []{ if tag.version == nil { tag.version = "1.1.0" } } } ) static var stages: [MigrationStage] { [stage1] } } Here's the model container: var sharedModelContainer: ModelContainer = { let schema = Schema(versionedSchema: DataSchemaV2.self) let modelConfiguration = ModelConfiguration(schema: schema, isStoredInMemoryOnly: false) do { return try ModelContainer( for: schema, migrationPlan: MigrationPlanV2.self, configurations: [modelConfiguration]) } catch { fatalError("Could not create ModelContainer: \(error)") } }() I ran a similar test prior to this, and got the same result. It's like the code in my willMigrate isn't running. I also had print statements in there that I never saw printed to the console. I tried to check the CloudKit console for any information, but I'm having issues with that as well (separate post). Anyways, how can I confirm that my migration was successful here?

I previously got this error when I used a PassKey to log in. I'm not using that. I've put my password in multiple times, closed the browser, etc. It doesn't seem to be working. The only thing I can think is that because my Mac is using a different iCloud account, it's not letting me. Does anyone have any ideas?

Hey folks, I'm having an issue where iCloud sync is only working in the Development environment, not on Prod. I have deployed the schema to Prod through the CloudKit console, although I did it after the app went live on the AppStore. Even though the two schema are identical, iCloud sync just doesn't work on Prod. Things I tried on the code side: Initially I did the most basic SwiftData+CloudKit setup: var modelContainer: ModelContainer { let schema = Schema([Book.self, Goal.self]) let config = ModelConfiguration(isStoredInMemoryOnly: false, cloudKitDatabase: doesUserSyncToiCloud ? .automatic : .none) var container: ModelContainer do { container = try ModelContainer(for: schema, configurations: config) } catch { fatalError() } return container } var body: some Scene { WindowGroup { AnimatedSplashScreen { MainTabView() } } .modelContainer(modelContainer) } This is enough to make iCloud sync work at the Development level. Then when I noticed the issues on Prod I did some digging and found this on the Docs (https://developer.apple.com/documentation/swiftdata/syncing-model-data-across-a-persons-devices): let config = ModelConfiguration() do { #if DEBUG // Use an autorelease pool to make sure Swift deallocates the persistent // container before setting up the SwiftData stack. try autoreleasepool { let desc = NSPersistentStoreDescription(url: config.url) let opts = NSPersistentCloudKitContainerOptions(containerIdentifier: "iCloud.com.example.Trips") desc.cloudKitContainerOptions = opts // Load the store synchronously so it completes before initializing the // CloudKit schema. desc.shouldAddStoreAsynchronously = false if let mom = NSManagedObjectModel.makeManagedObjectModel(for: [Trip.self, Accommodation.self]) { let container = NSPersistentCloudKitContainer(name: "Trips", managedObjectModel: mom) container.persistentStoreDescriptions = [desc] container.loadPersistentStores {_, err in if let err { fatalError(err.localizedDescription) } } // Initialize the CloudKit schema after the store finishes loading. try container.initializeCloudKitSchema() // Remove and unload the store from the persistent container. if let store = container.persistentStoreCoordinator.persistentStores.first { try container.persistentStoreCoordinator.remove(store) } } } #endif modelContainer = try ModelContainer(for: Trip.self, Accommodation.self, configurations: config) } catch { fatalError(error.localizedDescription) } I've no idea why Apple would include this CoreData setup in a SwiftData documentation, but I went ahead and adapted it to my code as well. I see now that some new "assets" were added to my Development schema, but I'm afraid to deploy these changes to Prod, since I'm not even confident that this CoreData setup is necessary in a SwiftData app. Does anyone have any thoughts on this? Have you run into similar issues? Any help would be much appreciated; thanks!

I've realized that I need to use migration plans, but those required versioned schemas. I think I've updated mine, but I wanted to confirm if this was the proper procedure. To start, none of my models were versioned. I've since wrapped them in a VersionedSchema like this: enum TagV1: VersionedSchema { static var versionIdentifier: Schema.Version = .init(1, 0, 0) static var models: [any PersistentModel.Type] { [Tag.self] } @Model final class Tag { var id = UUID() var name: String = "" // Relationships var transactions: [Transaction]? = nil init(name: String) { self.name = name } } } I also created a type alias to point to this. typealias Tag = TagV1.Tag This is what my container looks like in my app file. var sharedModelContainer: ModelContainer = { let schema = Schema([ Tag.self ]) let modelConfiguration = ModelConfiguration(schema: schema, isStoredInMemoryOnly: false) do { return try ModelContainer(for: schema, configurations: [modelConfiguration]) } catch { fatalError("Could not create ModelContainer: \(error)") } }() The application builds and run successfully. Does this mean that my models are successfully versioned now? I'm trying to avoid an error I came across in earlier testing. That occurred because none of my models were versioned and I tried to setup a migration plan Cannot use staged migration with an unknown coordinator model version.

Is it possible to reset SwiftData to a state identical to that of a newly installed app? I have experienced some migration issues where, when I add a new model, I need to reinstall the entire application for the ModelContainer creation to work. Deleting all existing models does not seem to make any difference. A potential solution I currently have, which appears to work but feels quite hacky, is as follows: let _ = try! ModelContainer() modelContainer = try! ModelContainer(for: Student.self, ...) This seems to force out this error CoreData: error: Error: Persistent History (66) has to be truncated due to the following entities being removed: (...) which seems to reset SwiftData. Any other suggestions?

I have an app that uses SwiftData with CloudKit to synchronize data across a users devices. I'm able to replicate data created on one device on another and when removing data, it is also removed on the other device. So, I know that SwiftData and CloudKit are configured correctly. What I'd like to do though, is to ensure that if a user installs the app on an additional device, that the data is synchronized upon app start. When testing my app on a third device, via TestFlight, there was no data in the app upon launch even though all three devices are using the same Apple account (e.g. Apple ID). What is the best way to achieve this?

I'm trying to add Cloud Kit integration to SwiftData app (that is already in the App Store, btw). When the app is installed on devices that are directly connected to Xcode, it works (a bit slow, but pretty well). But when the app is distributed to Testflight internal testers, the synchronization doesn't happen at all. So, is this situation normal and how can I test apps with iCloud integration properly?

My macOS app is developed using SwfitUI, SwiftData, and CloudKit. In the development environment, CloudKit works well. Locally added models can be quickly viewed in the CloudKit Console. macOS app and iOS app with the same BundleID can also synchronize data normally when developing locally. However, in the production environment, the macOS app cannot synchronize data with iCloud. But iOS app can. The models added in the production environment are only saved locally and cannot be viewed in CloudKit Console Production. I am sure I have configured correctly, container schema changes to deploy to the Production environment. I think there may be a problem with CloudKit in macOS. Please help troubleshoot the problem. I can provide you with any information you need. var body: some Scene { WindowGroup { MainView() .frame(minWidth: 640, minHeight: 480) .environment(mainViewModel) } .modelContainer(for: [NoteRecord.self]) } I didn't do anything special. I didn’t do anything special. I just used SwiftData hosted by CloudKit.

Let's say I have a CloudKit database schema where I have records of type Author that are referenced by multiple records of type Article. I want to delete an Author record if no Article is referencing it. Now consider the following conflict: device A deleted the last Article referencing Author #42 device B uploads a new Article referencing Author #42 at the same time The result should be that Author #42 is not deleted after both operations are finished. But both device don't know from each other changes. So either device B could miss that device A deleted the author. Or device A could have missed that a new Article was uploaded and therefore the Author #42 was deleted right after the upload of device B. I though about using a reference count first. But this won't work if the ref count is part of the Author record. This is because deletions do not use the changeTag to detect lost updates: If device A found a reference count 0 and decides to delete the Author, it might miss that device B incremented the count meanwhile. I currently see two alternatives: Using a second record that outlives the Author to keep the reference count and using an atomic operation to update and delete it. So if the update fails, the delete would fail either. Always adding a new child record to the Author whenever a reference is made. We could call it ReferenceToken. Since child records may not become dangling, CloudKit would stop a deletion, if a new ReferenceToken sets the parent reference to the Author. Are there any better ways doing this?

I'm getting a crash in SwiftData but only on one specific device (iPhone 16 pro running 18.2 22C5131e) and not on an ipad or simulator I cant troubleshoot this crash and its quite frustrating, all I am getting is @Query(sort: \Todo.timestamp, order: .reverse) private var todos: [Todo] ForEach(todos.filter { !$0.completed }) { item in // <---crash TodoListView() } and the error is Thread 1: signal SIGABRT An abort signal terminated the process. Such crashes often happen because of an uncaught exception or unrecoverable error or calling the abort() function. and _SwiftData_SwiftUI.Query.wrappedValue.getter : τ_0_1 -> 0x105b98b58 <+160>: ldur x8, [x29, #-0x40] 0x105b98b5c <+164>: ldur x0, [x29, #-0x38] 0x105b98b60 <+168>: ldur x1, [x29, #-0x30] 0x105b98b64 <+172>: ldur x9, [x29, #-0x20] 0x105b98b68 <+176>: stur x9, [x29, #-0x28] 0x105b98b6c <+180>: ldr x8, [x8, #0x8] 0x105b98b70 <+184>: blr x8 0x105b98b74 <+188>: ldur x0, [x29, #-0x28] 0x105b98b78 <+192>: sub sp, x29, #0x10 0x105b98b7c <+196>: ldp x29, x30, [sp, #0x10] 0x105b98b80 <+200>: ldp x20, x19, [sp], #0x20 0x105b98b84 <+204>: ret How do I fix this?

How can I set the display name of the CloudKit container in Settings -> iCloud -> Manage Storage. I have multiple containers, some legacy, and some for certain modules that are shared among a suite of apps. The problem is all Containers show the same name so it is not possible to advise a user which containers are safe to delete. I am using NSPersistentCloudKitContainer.

I'm using NSPersistentCloudKitContainer to save, edit, and delete items, but it only works half of the time. When I delete an item and terminate the app and repoen, sometimes the item is still there and sometimes it isn't. The operations are simple enough: moc.delete(thing) try? moc.save() Here is my DataController. I'm happy to provide more info as needed class DataController: ObservableObject { let container: NSPersistentCloudKitContainer @Published var moc: NSManagedObjectContext init() { container = NSPersistentCloudKitContainer(name: "AppName") container.loadPersistentStores { description, error in if let error = error { print("Core Data failed to load: \(error.localizedDescription)") } } #if DEBUG do { try container.initializeCloudKitSchema(options: []) } catch { print("Error initializing CloudKit schema: \(error.localizedDescription)") } #endif moc = container.viewContext } }

Are SwiftData queries lazy loaded when used in conjunction with SwiftUI List? @Query var posts: [PostModel] List { ForEach(posts, id: \.id) { post in PostView(post) } } If the code above is not lazy loaded, how can we make it lazy loaded?

The same macOS app is logged into the same iCloud account on two Macs. The apps on both devices can sync data with iCloud, but the data between them is isolated. When I was developing, I just enabled the CloudKit(SwiftData host in iCloud) capability and did not do anything special. I thought that the same app and the same iCloud account should sync the same data between different devices. Why is the cloud data on these two Macs isolated?

I have a CKRecord that references an CKAsset. If I understand it correctly, CKSyncEngine would download the asset every time the record has changed on the server. (Of course it would try to use the local asset cache, but worst-case it might be already flushed) The documentation for CKAsset says that asset downloads can be prevented by limiting the requested record keys using the desiredKeys property on the fetch operation. But I don't see any possibility to set this property when using CKSyncEngine. Did I miss something? Are there any alternatives?

I couldn't get iCloud root directory ("iCloud Drive not available or user domain not found."). Anybody had similar issue? I don't want to CloudKit. Xcode: Version 16.0 I have done below: Settings > iCloud Backup ON Settings > iCloud > iCloud Drive ON Settings > iCloud > MyApp ON import Foundation import UIKit class BackupManager { var isiCloudEnabled: Bool { (FileManager.default.ubiquityIdentityToken != nil) } // Get the iCloud Drive folder and create a folder if needed func createFolder() -> URL? { let fileManager = FileManager.default // Access the iCloud Drive root directory (user-visible folder) guard let iCloudRootURL = fileManager.url(forUbiquityContainerIdentifier: nil)? .appendingPathComponent("Documents") else { print("iCloud Drive not available or user domain not found.") return nil } // Check if the folder exists in iCloud Drive root, if not, create it if !fileManager.fileExists(atPath: iCloudRootURL.path) { do { try fileManager.createDirectory(at: iCloudRootURL, withIntermediateDirectories: true, attributes: nil) print("Folder created in iCloud Drive") } catch { print("Error creating folder: \(error.localizedDescription)") return nil } } // Return the URL of the folder in iCloud Drive return iCloudRootURL } }

I have an app and widget that share access to a SwiftData container using App Groups. I have implemented a SwiftData migration plan, but I am unsure whether I should allow the widget to perform the migration (in addition to the app). I am concerned about two possible issues: If the app and widget are run at approximately the same time (e.g. the user taps Open after doing a manual update in the App Store), then both the app and widget might try to perform the migration at the same time, which could lead to race conditions / data corruption. If the widget is first to run but the widget gets suspended for some reasons (e.g., iOS decides it's using too many resources), then the migration might be suspended leaving the database in an corrupted state. To me, it feels like the safest option is to only allow the app itself to perform the migration – this will ensure that the migration can only happen once in a safe state. However, this will lead to problems for the widget. For example, if the user does not open the app for several days after an automatic update, the widget will be in a broken state, since it will not be able to open the container until it has been migrated by the app. Possible solutions I'm considering: Allow both the app and widget to perform the migration and cross my fingers. (Ignore Issue 1 and Issue 2) Implement some kind of UserDefaults flag that is set to true during migration, so that the app and widget will avoid performing the migration concurrently. (Solves Issue 1 but not Issue 2) Only perform the migration in the app, and then add code to the widget to detect which container version the widget has access to, so that the widget can continue to work with a v1 container until the app eventually updates it to a v2 container. (Solves Issue 1 and Issue 2, but leads to very convoluted code – especially over time) Things I'm unsure about: Will iOS continue to use v1 of the widget until the app is opened for the first time, at which point v2 of the widget is installed? Or does iOS immediately update the widget to v2 on update? Does iOS immediately refresh the widget timeline on update? Does SwiftData already have some logic to avoid migrations being performed twice, even from different threads? If so, how does it respond if one process tries to access a container while another process is performing a migration? Does anyone have any recommendations about how to handle these possible issues? What are best practices? Cheers!

Only development environment can real sync. But product environment can't sync. And when run my device show this error: CoreData: Already have a mirrored relationship registered for this key: CD_M2M_Event_items:B269B612-37A6-4ED7-9FDB-601E88BF56A8:8DC64E4A-E893-4465-8B21-48CF1C52A4BC <NSCKMirroredRelationship: 0x302bb9950> (entity: NSCKMirroredRelationship; id: 0xa049af3fb0190928 <x-coredata://BEB6E57C-891C-4E71-B92F-7BAA0844913E/NSCKMirroredRelationship/p1747>; data: { cdEntityName = Event; ckRecordID = "B5908A8A-079E-482C-9F2E-1309BF071F0E"; ckRecordSystemFields = nil; isPending = 0; isUploaded = 0; needsDelete = 0; recordName = "B269B612-37A6-4ED7-9FDB-601E88BF56A8"; recordZone = "0xa049af3f6a5909a8 <x-coredata://BEB6E57C-891C-4E71-B92F-7BAA0844913E/NSCKRecordZoneMetadata/p1>"; relatedEntityName = Item; relatedRecordName = "8DC64E4A-E893-4465-8B21-48CF1C52A4BC"; relationshipName = items; }) <decode: bad range for [%@] got [offs:941 len:665 within:0]> And my product core data sync data only to October 24, 2024. The data before October 24 was synchronized normally, Nothing after October 24 is synced.

I changed an enum value from this: enum Kind: String, Codable, CaseIterable { case credit } to this: enum Kind: String, Codable, CaseIterable { case credit = "Credit" } And now it fails to load the data. This is inside of a SwiftData model. I get why the error is occurring, but is there a way to resolve this issue without having to revert back or delete the data? Error: dataCorrupted(Swift.DecodingError.Context(codingPath: [], debugDescription: "Cannot initialize Kind from invalid String value credit", underlyingError: nil))