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SwiftData crash on fetch
I have a strange crash which I have problems understanding. It only happens on a few devices, after a ModelContainer migration, and it doesn't seem to crash on the migration itself. The fetch is done in onAppear, and shouldn't necessarily result in a crash, as it is an optional try: let request = FetchDescriptor<Rifle>() let data = try? modelContext.fetch(request) if let data, !data.isEmpty { rifle = data.first(where: { $0.uuid.uuidString == settings.selectedRifleId }) ?? data.first! } When I get logs from users, there seems to be an error in encoding? Exception Type: EXC_BREAKPOINT (SIGTRAP) Exception Codes: 0x0000000000000001, 0x000000018e8bfd78 Termination Reason: SIGNAL 5 Trace/BPT trap: 5 Terminating Process: exc handler [71687] Triggered by Thread: 0 Thread 0 name: Dispatch queue: com.apple.main-thread Thread 0 Crashed: 0 libswiftCore.dylib 0x18e8bfd78 _assertionFailure(_:_:file:line:flags:) + 264 1 SwiftData 0x24e18b480 0x24e14c000 + 259200 2 SwiftData 0x24e193968 0x24e14c000 + 293224 3 SwiftData 0x24e195a78 0x24e14c000 + 301688 4 libswiftCore.dylib 0x18e8e4084 _KeyedEncodingContainerBox.encodeNil<A>(forKey:) + 352 5 libswiftCore.dylib 0x18e8d79f0 KeyedEncodingContainer.encodeNil(forKey:) + 64 6 SwiftData 0x24e19f09c 0x24e14c000 + 340124 7 SwiftData 0x24e1a3dec 0x24e14c000 + 359916 8 libswiftCore.dylib 0x18ec10be8 dispatch thunk of Encodable.encode(to:) + 32 9 SwiftData 0x24e1cd500 0x24e14c000 + 529664 10 SwiftData 0x24e1cd0c8 0x24e14c000 + 528584 11 SwiftData 0x24e1da960 0x24e14c000 + 584032 12 SwiftData 0x24e1ee2ec 0x24e14c000 + 664300 13 SwiftData 0x24e1d97d8 0x24e14c000 + 579544 14 SwiftData 0x24e1eada0 0x24e14c000 + 650656 15 SwiftData 0x24e1d989c 0x24e14c000 + 579740 16 SwiftData 0x24e1eee78 0x24e14c000 + 667256 17 Impact 0x1027403bc 0x10268c000 + 738236
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Jun ’25
Swift Data Predicate Evaluation Crashes in Release Build When Generics Used
I'm using Swift Data for an app that requires iOS 18. All of my models conform to a protocol that guarantees they have a 'serverID' String variable. I wrote a function that would allow me to pass in a serverID String and have it fetch the model object that matched. Because I am lazy and don't like writing the same functions over and over, I used a Self reference so that all of my conforming models get this static function. Imagine my model is called "WhatsNew". Here's some code defining the protocol and the fetching function. protocol RemotelyFetchable: PersistentModel { var serverID: String { get } } extension WhatsNew: RemotelyFetchable {} extension RemotelyFetchable { static func fetchOne(withServerID identifier: String, inContext modelContext: ModelContext) -> Self? { var fetchDescriptor = FetchDescriptor<Self>() fetchDescriptor.predicate = #Predicate<Self> { $0.serverID == identifier } do { let allModels = try modelContext.fetch(fetchDescriptor) return allModels.first } catch { return nil } } } Worked great! Or so I thought... I built this and happily ran a debug build in the Simulator and on devices for months while developing the initial version but when I went to go do a release build for TestFlight, that build reliably crashed on every device with a message like this: SwiftData/DataUtilities.swift:65: Fatal error: Couldn't find \WhatsNew. on WhatsNew with fields [SwiftData.Schema.PropertyMetadata(name: "serverID", keypath: \WhatsNew., defaultValue: nil, metadata: Optional(Attribute - name: , options: [unique], valueType: Any, defaultValue: nil, hashModifier: nil)), SwiftData.Schema.PropertyMetadata(name: "title", keypath: \WhatsNew., defaultValue: nil, metadata: nil), SwiftData.Schema.PropertyMetadata(name: "bulletPoints", keypath: \WhatsNew.)>, defaultValue: nil, metadata: nil), SwiftData.Schema.PropertyMetadata(name: "dateDescription", keypath: \WhatsNew., defaultValue: nil, metadata: nil), SwiftData.Schema.PropertyMetadata(name: "readAt", keypath: \WhatsNew.)>, defaultValue: nil, metadata: nil)] It seems (cannot confirm) that something in the release build optimization process is stripping out some metadata / something about these models that makes this predicate crash. Tested on iOS 18.0 and 18.1 beta. How can I resolve this? I have two dozen types that conform to this protocol. I could manually specialize this function for every type myself but... ugh.
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1.6k
Oct ’25
Swiftdata cloudkit synchronization issues
Hi, I did cloudkit synchronization using swiftdata. However, synchronization does not occur automatically, and synchronization occurs intermittently only when the device is closed and opened. For confirmation, after changing the data in Device 1 (saving), when the data is fetched from Device 2, there is no change. I've heard that there's still an issue with swiftdata sync and Apple is currently troubleshooting it, is the phenomenon I'm experiencing in the current version normal?
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655
Oct ’25
SwiftData crash when using a @Query sort descriptor with a relationship
I am using SwiftData for storage and have a view that uses the @Query property wrapper with a sort descriptor that points to a relationship on a model. In a release build on device running iOS 18.3, the app crashes. This is the line that crashes: @Query(sort: \Item.info.endDate, order: .reverse) private var items: [Item] Item has a relationship to ItemInfo, which is where the endDate property is defined. This code works in debug and on a simulator. In the project referenced here: https://github.com/lepolt/swiftdata-crash, change the scheme build configuration to “Release” and run on device. The app will crash. Using Xcode Version 16.2 (16C5032a) iPhone 12, iOS 18.3 (22D60)
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1.6k
Aug ’25
CKSyncEngine: Duplicate FetchedRecordZoneChanges & Sync Handling Questions
Hi everyone, I've recently implemented CKSyncEngine in my app, and I have two questions regarding its behavior: Duplicate FetchedRecordZoneChanges After Sending Changes: I’ve noticed that the engine sometimes receives a FetchedRecordZoneChanges event containing modifications and deletions that were just sent by the same device a few moments earlier. This event arrives after the SentRecordZoneChanges event, and both events share the same recordChangeTag, which results in double-handling the record. Is this expected behavior? I’d like to confirm if this is how CKSyncEngine works or if I might be overlooking something. Handling Initial Sync with a "Sync Screen": When a user opens the app for the first time and already has data stored in iCloud, I need to display a "Sync Screen" temporarily to prevent showing partial data or triggering abrupt, rapid UI changes. I’ve found that canceling current operations, then awaiting sendChanges() and fetchChanges() works well to ensure data is fully synced before dismissing the sync screen: displaySyncScreen = true await syncEngine.cancelOperations() try await syncEngine.sendChanges() try await syncEngine.fetchChanges() displaySyncScreen = false However, I’m unsure if canceling operations like this could lead to data loss or other issues. Is this a safe approach, or would you recommend a better strategy for handling this initial sync state?
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1k
Apr ’26
SwiftData property marked ephemeral getting persisted in CloudKit
Am I misunderstanding the expected behavior here, or is there a bug in the behavior of @Attribute(.ephemeral) tagged SwiftData model properties? The documentation for .ephemeral says "Track changes to this property but do not persist". I started using .ephemeral because @Transient was inhibiting SwiftUI from reacting to changes to the property through @Observable. I am updating the value of my @Attribute(.ephemeral) property about once a second and I am seeing corresponding console log output showing the property as part of the generated CKRecord object. I then confirmed in the CloudKit dev portal that the .ephemeral property was added to the Record schema and contains real values. The behavior seems as though the .ephemeral property is being completely ignored. This is observed in a new Xcode project using SwiftData with CloudKit, Xcode 16.2, macOS 15.3.1 and during Build & Run testing on physical devices.
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1.1k
Apr ’26
SwiftData migration error: NSCloudKitMirroringDelegate are not reusable
Hello everyone, I used SwiftData for v1 of an app and am now trying to make changes to the schema for v2. I created the v2 schema that adds a property to one of the models. I need to populate the new property so I made a custom migration using didMigrate. However that doesn't seem to matter what I do in the migration because creating the ModelContainer throws an error before didMigrate ever gets called. The error is: Unresolved error loading container Error Domain=NSCocoaErrorDomain Code=134060 "A Core Data error occurred." UserInfo={NSLocalizedFailureReason=Instances of NSCloudKitMirroringDelegate are not reusable and should have a lifecycle tied to a given instance of NSPersistentStore.} Higher up in the Xcode output I see things like this (in order): Request 'D25A8CB8-7341-4FA8-B2F8-3DE2D35B5273' was cancelled because the store was removed from the coordinator. BUG IN CLIENT OF CLOUDKIT: Registering a handler for a CKScheduler activity identifier that has already been registered CloudKit setup failed because it couldn't register a handler for the export activity. There is another instance of this persistent store actively syncing with CloudKit in this process. How can I know from this output what I am doing incorrectly? Any idea what I should take a look at or try to do differently? This is a simple app with three models and nothing fancy. The only change in the schema is to add a property. The new property is declared as optional and has an inverse that is also declared as optional. Thanks for any insight!
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1.7k
Aug ’25
How to make a hidden iCloud Container active again?
While experimenting with CloudKit dashboard, I accidentally turned off a iCloud container. Now in the Certificates, Identifiers & Profiles section of developer portal, this iCloud container identifier is listed under "hidden" not "active" I can edit its name but there is not way to unhide or active it again. What am I missing?
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380
Nov ’25
Using relationships in SortDescriptor crashing on release
If use a SortDescriptor for a model and sort by some attribute from a relationship, in DEBUG mode it all works fine and sorts. However, in release mode, it is an instant crash. SortDescriptor(.name, order: .reverse) ---- works SortDescriptor(.assignedUser?.name, order: .reverse) ---- works in debug but crash in release. What is the issue here, is it that SwiftData just incompetent to do this?
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133
Aug ’25
Core Data Multiple NSEntityDescriptions claim the NSManagedObject subclass
Hello everyone, I'm trying to adopt the new Staged Migrations for Core Data and I keep running into an error that I haven't been able to resolve. The error messages are as follows: warning: Multiple NSEntityDescriptions claim the NSManagedObject subclass 'Movie' so +entity is unable to disambiguate. warning: 'Movie' (0x60000350d6b0) from NSManagedObjectModel (0x60000213a8a0) claims 'Movie'. error: +[Movie entity] Failed to find a unique match for an NSEntityDescription to a managed object subclass This happens for all of my entities when they are added/fetched. Movie is an abstract entity subclass, and it has the error error: +[Movie entity] Failed to find which is unique to the subclass entities, but this occurs for all entities. The NSPersistentContainer is loaded only once, and I set the following option after it's loaded: storeDescription.setOption( [stages], forKey: NSPersistentStoreStagedMigrationManagerOptionKey ) The warnings and errors only appear after I fetch or save to context. It happens regardless of whether the database was migrated or not. In my test project, using the generic NSManagedObject with NSEntityDescription.insertNewObject(forEntityName: "MyEntity", into: context) does not cause the issue. However, using the generic NSManagedObject is not a viable option for my app. Setting the module to "Current Project Module" doesn't change anything, except that it now prints "claims 'MyModule.Show'" in the warnings. I have verified that there are no other entities with the same name or renameIdentifier. Has anyone else encountered this issue, or can offer any suggestions on how to resolve it? Thanks in advance for any help!
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2w
Fetching data with relationships directly faults the relationships even when not accessed
I am using SwiftData to model my data. For that i created a model called OrganizationData that contains various relationships to other entities. My data set is quite large and i am having a big performance issue when fetching all OrganizationData entities. I started debugging and looking at the sql debug log i noticed that when fetching my entities i run into faults for all relationships even when not accessing them. Fetching my entities: let fetchDescriptor = FetchDescriptor<OrganizationData>() let context = MapperContext(dataManager: self) let organizations = (try modelContainer.mainContext.fetch(fetchDescriptor)) Doing this fetch, also fetches all relationships. Each in a single query, for every OrganizationData entity. CoreData: annotation: to-many relationship fault "relationship1" for objectID 0x8aa5249772916e00 <x-coredata://B891FCEB-DF16-4E11-98E6-0AFB5D171A81/OrganizationData/p3869> fulfilled from database. Got 9 rows CoreData: annotation: to-many relationship fault "relationship2" for objectID 0x8aa5249772916e00 <x-coredata://B891FCEB-DF16-4E11-98E6-0AFB5D171A81/OrganizationData/p3869> fulfilled from database. Got 0 rows CoreData: annotation: to-many relationship fault "relationship3" for objectID 0x8aa5249772916e00 <x-coredata://B891FCEB-DF16-4E11-98E6-0AFB5D171A81/OrganizationData/p3869> fulfilled from database. Got 0 rows CoreData: annotation: to-many relationship fault "relationship4" for objectID 0x8aa5249772916e00 <x-coredata://B891FCEB-DF16-4E11-98E6-0AFB5D171A81/OrganizationData/p3869> fulfilled from database. Got 0 rows CoreData: annotation: to-many relationship fault "relationship5" for objectID 0x8aa5249772916e00 <x-coredata://B891FCEB-DF16-4E11-98E6-0AFB5D171A81/OrganizationData/p3869> fulfilled from database. Got 0 rows CoreData: annotation: to-many relationship fault "relationship6" for objectID 0x8aa5249772916e00 <x-coredata://B891FCEB-DF16-4E11-98E6-0AFB5D171A81/OrganizationData/p3869> fulfilled from database. Got 0 rows CoreData: annotation: to-many relationship fault "relationship7" for objectID 0x8aa5249772916e00 <x-coredata://B891FCEB-DF16-4E11-98E6-0AFB5D171A81/OrganizationData/p3869> fulfilled from database. Got 1 rows CoreData: annotation: to-many relationship fault "relationship8" for objectID 0x8aa5249772916e00 <x-coredata://B891FCEB-DF16-4E11-98E6-0AFB5D171A81/OrganizationData/p3869> fulfilled from database. Got 0 rows CoreData: annotation: to-many relationship fault "relationship9" for objectID 0x8aa5249772916e00 <x-coredata://B891FCEB-DF16-4E11-98E6-0AFB5D171A81/OrganizationData/p3869> fulfilled from database. Got 0 rows The relationships are all defined the same @Relationship(deleteRule: .cascade, inverse: \EntityData1.organization) var relationship1: [EntityData1] = [] Am i missing something? As far as i understood relationships are lazy and should only be faulted when accessing the property. But doing the fetch as described above already causes a query to happen, making the fetch take very long when using a large data set.
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470
Aug ’25
SwiftData 100% crash when fetching history with codable (test included!)
SwiftData crashes 100% when fetching history of a model that contains an optional codable property that's updated: SwiftData/Schema.swift:389: Fatal error: Failed to materialize a keypath for someCodableID.someID from CrashModel. It is possible that this path traverses a type that does not work with append(), please file a bug report with a test. Would really appreciate some help or even a workaround. Code: import Foundation import SwiftData import Testing struct VaultsSwiftDataKnownIssuesTests { @Test func testCodableCrashInHistoryFetch() async throws { let container = try ModelContainer( for: CrashModel.self, configurations: .init( isStoredInMemoryOnly: true ) ) let context = ModelContext(container) try SimpleHistoryChecker.hasLocalHistoryChanges(context: context) // 1: insert a new value and save let model = CrashModel() model.someCodableID = SomeCodableID(someID: "testid1") context.insert(model) try context.save() // 2: check history it's fine. try SimpleHistoryChecker.hasLocalHistoryChanges(context: context) // 3: update the inserted value before then save model.someCodableID = SomeCodableID(someID: "testid2") try context.save() // The next check will always crash on fetchHistory with this error: /* SwiftData/Schema.swift:389: Fatal error: Failed to materialize a keypath for someCodableID.someID from CrashModel. It is possible that this path traverses a type that does not work with append(), please file a bug report with a test. */ try SimpleHistoryChecker.hasLocalHistoryChanges(context: context) } } @Model final class CrashModel { // optional codable crashes. var someCodableID: SomeCodableID? // these actually work: //var someCodableID: SomeCodableID //var someCodableID: [SomeCodableID] init() {} } public struct SomeCodableID: Codable { public let someID: String } final class SimpleHistoryChecker { static func hasLocalHistoryChanges(context: ModelContext) throws { let descriptor = HistoryDescriptor<DefaultHistoryTransaction>() let history = try context.fetchHistory(descriptor) guard let last = history.last else { return } print(last) } }
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3d
Migrating a swiftData project to CloudKit to implement iCloudSync.
My project is using swiftData and I want to implement iCloud sync in it. Now, my data base doesnt have any optional attributes or relationships and CloudKit wants them to be optional. So, rather than editing all code with unwrapping code for the optionals, how can I provide a bridge that does so in the last stage of actually saving to the store? Sort of, capture it in a proxy object before writing and after reading from the store. Is there a neat way that can save a lot of debugging? I have code snippets from chat gpt and they are hard to debug. This is my first project in swiftUI. Thanks. Neerav
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287
Jun ’25
CKSyncEngine on macOS: Automatic Fetch Extremely Slow Compared to iOS
Hi everyone, We’re currently using CKSyncEngine to sync all our locally persisted data across user devices (iOS and macOS) via iCloud. We’ve noticed something strange and reproducible: On iOS, when the CKSyncEngine is initialized with manual sync behavior, both manual calls to fetchChanges() and sendChanges() happen nearly instantly (usually within seconds). Automatic syncing is also very fast. On macOS, when the CKSyncEngine is initialized with manual sync behavior, fetchChanges() and sendChanges() are also fast and responsive. However, once CKSyncEngine is initialized with automatic syncing enabled on macOS: sendChanges() still appears to transmit changes immediately. But automatic fetching becomes significantly slower — often taking minutes to pick up changes from the cloud, even when new data is already available. Even manual calls to fetchChanges() behave as if they’re throttled or delayed, rather than performing an immediate fetch. Our questions: Is this delay in automatic (and post-automatic manual) fetch behavior on macOS expected, or possibly a bug? Are there specific macOS constraints that impact CKSyncEngine differently than on iOS? Once CKSyncEngine has been initialized in automatic mode, is fetchChanges() no longer treated as a truly manual trigger? Is there a recommended workaround to enable fast sync behavior on macOS — for example, by sticking to manual sync configuration and triggering sync using a CKSubscription-based mechanism when remote changes occur? Any guidance, clarification, or experiences from other developers (or Apple engineers) would be greatly appreciated — especially regarding maintaining parity between iOS and macOS sync performance. Thanks in advance!
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186
Oct ’25
iCloud sync issues using NSPersistentCloudKitContainer for Core Data + CloudKit sync.
I have tried to set up iCloud sync. Despite fully isolating and resetting my development environment, the app fails with: NSCocoaErrorDomain Code=134060 (PersistentStoreIncompatibleVersionHashError) What I’ve done: Created a brand new CloudKit container Created a new bundle ID and app target Renamed the Core Data model file itself Set a new model version Used a new .sqlite store path Created a new .entitlements file with the correct container ID Verified that the CloudKit dashboard shows no records Deleted and reinstalled the app on a real device Also tested with “Automatically manage signing” and without Despite this, the error persists. I am very inexperienced and am not sure what my next step is to even attempt to fix this. Any guidance is apprecitated.
1
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230
Jun ’25
No persistent stores error in SwiftData
I am following Apple's instruction to sync SwiftData with CloudKit. While initiating the ModelContainer, right after removing the store from Core Data, the error occurs: FAULT: NSInternalInconsistencyException: This NSPersistentStoreCoordinator has no persistent stores (unknown). It cannot perform a save operation.; (user info absent) I've tried removing default.store and its related files/folders before creating the ModelContainer with FileManager but it does not resolve the issue. Isn't it supposed to create a new store when the ModelContainer is initialized? I don't understand why this error occurs. Error disappears when I comment out the #if DEBUG block. Code: import CoreData import SwiftData import SwiftUI struct InitView: View { @Binding var modelContainer: ModelContainer? @Binding var isReady: Bool @State private var loadingDots = "" @State private var timer: Timer? var body: some View { VStack(spacing: 16) { Text("Loading\(loadingDots)") .font(.title2) .foregroundColor(.gray) } .padding() .onAppear { startAnimation() registerTransformers() let config = ModelConfiguration() let newContainer: ModelContainer 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.my-container-identifier") desc.cloudKitContainerOptions = opts // Load the store synchronously so it completes before initializing the // CloudKit schema. desc.shouldAddStoreAsynchronously = false if let mom = NSManagedObjectModel.makeManagedObjectModel(for: [Page.self]) { let container = NSPersistentCloudKitContainer(name: "Pages", 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) } } // let fileManager = FileManager.default // let sqliteURL = config.url // let urls: [URL] = [ // sqliteURL, // sqliteURL.deletingLastPathComponent().appendingPathComponent("default.store-shm"), // sqliteURL.deletingLastPathComponent().appendingPathComponent("default.store-wal"), // sqliteURL.deletingLastPathComponent().appendingPathComponent(".default_SUPPORT"), // sqliteURL.deletingLastPathComponent().appendingPathComponent("default_ckAssets") // ] // for url in urls { // try? fileManager.removeItem(at: url) // } } #endif newContainer = try ModelContainer(for: Page.self, configurations: config) // ERROR!!! } catch { fatalError(error.localizedDescription) } modelContainer = newContainer isReady = true } .onDisappear { stopAnimation() } } private func startAnimation() { timer = Timer.scheduledTimer( withTimeInterval: 0.5, repeats: true ) { _ in updateLoadingDots() } } private func stopAnimation() { timer?.invalidate() timer = nil } private func updateLoadingDots() { if loadingDots.count > 2 { loadingDots = "" } else { loadingDots += "." } } } import CoreData import SwiftData import SwiftUI @main struct MyApp: App { @State private var modelContainer: ModelContainer? @State private var isReady: Bool = false var body: some Scene { WindowGroup { if isReady, let modelContainer = modelContainer { ContentView() .modelContainer(modelContainer) } else { InitView(modelContainer: $modelContainer, isReady: $isReady) } } } }
2
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298
May ’25
Default zone is not accessible in shared DB - cloudKit
I am trying to save to cloud kit shared database. The shared database does not allow zones to be set up. How do I save to sharedCloudDatabase without a zone? private func addItem(recordType: String, name: String) { let record = CKRecord(recordType: recordType) record[Constances.field.name] = name as CKRecordValue record[Constances.field.done] = false as CKRecordValue record[Constances.field.priority] = 0 as CKRecordValue CKContainer.default().sharedCloudDatabase.save(record) { [weak self] returnRecord, error in if let error = error { print("Error saving record: \(record[Constances.field.name] as? String ?? "No Name"): \n \(error)") return } } } The following error message prints out: Error saving record: Milk: &lt;CKError 0x15af87900: "Server Rejected Request" (15/2027); server message = "Default zone is not accessible in shared DB"; op = B085F7BA703D4A08; uuid = 87AEFB09-4386-4E43-81D7-971AAE8BA9E0; container ID = "iCloud.com.sfw-consulting.Family-List"&gt;
1
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166
Jun ’25
Feedback/issues for SwiftData custom store
Hello, thank you Apple for supporting custom store with SwiftData and the Schema type is superb to work with. I have successfully set one up with SQL and have some feedback and issues regarding its APIs. There’s a highlighted message in the documentation about not using internal restricted symbols directly, but they contradict with the given protocols and I am concerned about breaking any App Store rules. Are we allowed to use these? If not, they should be opened up as they’re useful. BackingData is required to set up custom snapshots, initialization, and getting/setting values. And I want to use it with createBackingData() to directly initialize instances from snapshots when transferring them between server and client or concurrency. RelationshipCollection for casting to-many relationships from backing data or checking if an array contains a PersistentModel. SchemaProperty for type erasure in a collection. Schema.Relationship has KeyPath properties, but it is missing for Schema.Attribute and Schema.CompositeAttribute. Which means you can’t purely depend on the schema to map data. I am unable to access the properties of a custom struct type in a predicate unless I use Mirror with schemaMetadata() or CustomStringConvertible on the KeyPath directly to extract it. Trivial, but… the KeyPath property name is inconsistent (it’s all lowercase). It would be nice to retrieve property names from custom struct types, since you are unable access CodingKeys that are auto synthesized by Codable for structs. But I recently realized they’re a part Schema.CompositeAttribute, however I don’t know how to match these without the KeyPath… I currently map my entities using CodingKeys to their PredicateCodableKeyPathProviding.… but I wish for a simpler alternative! It’s unclear how to provide the schema to the snapshot before new models are created. I currently use a static property, but I want to make it flexible if more schemas and configurations are added later on. I considered saving and loading the schema in a temporary location, but doubtful that the KeyPath values will be available as they are not Codable. I suspect schemaMetadata() has the information I need to map the backing data without a schema for snapshots, but as mentioned previously, properties are inaccessible… Allow access to entity metatypes, like value types from SchemaProperty. They’re useful for getting data out of snapshots and casting them to CodingKeys and PredicateCodableKeyPathProviding. They do not carry over when you provide them in the Schema. I am unable to retrieve the primary key from PersistentIdentifier. It seems like once you create one, you can’t get it out, like the DataStoreConfiguration in ModelContainer is not the one you used to set it up. I cannot cast it, it is an entirely different struct? I have to use JSONSerialization to extract it, but I want to get it directly since it is not a column in my database. It is transformed when it goes to/from my tables. It’s unknown how to support some schema options, such as Spotlight and CloudKit. Allow for extending macro options, such as adding options to set as primary key, whether to auto increment, etc… You can create a schema for super and sub entities, but it doesn’t appear you can actually set them up from the @Model macro or use inheritance on these models… SwiftData history tracking seems incomplete for HistoryDelete, because that protocol requires HistoryTombstone, but this type cannot be instantiated, nor does it contain anything useful to infer from. As an aside, I want to create my own custom ModelActor that is a global actor. However, I’m unable to replicate the executor that Apple provides where the executor has a ModelContext, because this type does not conform to Sendable. So how did Apple do this? The documentation doesn’t mention unchecked Sendable, but I figure if the protocol is available then we would be able to set up our own. And please add concurrency features! Anyway, I hope for more continued support in the future and I am looking forward to what’s new this WWDC! 😊
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207
May ’25
SwiftData crash on fetch
I have a strange crash which I have problems understanding. It only happens on a few devices, after a ModelContainer migration, and it doesn't seem to crash on the migration itself. The fetch is done in onAppear, and shouldn't necessarily result in a crash, as it is an optional try: let request = FetchDescriptor<Rifle>() let data = try? modelContext.fetch(request) if let data, !data.isEmpty { rifle = data.first(where: { $0.uuid.uuidString == settings.selectedRifleId }) ?? data.first! } When I get logs from users, there seems to be an error in encoding? Exception Type: EXC_BREAKPOINT (SIGTRAP) Exception Codes: 0x0000000000000001, 0x000000018e8bfd78 Termination Reason: SIGNAL 5 Trace/BPT trap: 5 Terminating Process: exc handler [71687] Triggered by Thread: 0 Thread 0 name: Dispatch queue: com.apple.main-thread Thread 0 Crashed: 0 libswiftCore.dylib 0x18e8bfd78 _assertionFailure(_:_:file:line:flags:) + 264 1 SwiftData 0x24e18b480 0x24e14c000 + 259200 2 SwiftData 0x24e193968 0x24e14c000 + 293224 3 SwiftData 0x24e195a78 0x24e14c000 + 301688 4 libswiftCore.dylib 0x18e8e4084 _KeyedEncodingContainerBox.encodeNil<A>(forKey:) + 352 5 libswiftCore.dylib 0x18e8d79f0 KeyedEncodingContainer.encodeNil(forKey:) + 64 6 SwiftData 0x24e19f09c 0x24e14c000 + 340124 7 SwiftData 0x24e1a3dec 0x24e14c000 + 359916 8 libswiftCore.dylib 0x18ec10be8 dispatch thunk of Encodable.encode(to:) + 32 9 SwiftData 0x24e1cd500 0x24e14c000 + 529664 10 SwiftData 0x24e1cd0c8 0x24e14c000 + 528584 11 SwiftData 0x24e1da960 0x24e14c000 + 584032 12 SwiftData 0x24e1ee2ec 0x24e14c000 + 664300 13 SwiftData 0x24e1d97d8 0x24e14c000 + 579544 14 SwiftData 0x24e1eada0 0x24e14c000 + 650656 15 SwiftData 0x24e1d989c 0x24e14c000 + 579740 16 SwiftData 0x24e1eee78 0x24e14c000 + 667256 17 Impact 0x1027403bc 0x10268c000 + 738236
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9
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3
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954
Activity
Jun ’25
Swift Data Predicate Evaluation Crashes in Release Build When Generics Used
I'm using Swift Data for an app that requires iOS 18. All of my models conform to a protocol that guarantees they have a 'serverID' String variable. I wrote a function that would allow me to pass in a serverID String and have it fetch the model object that matched. Because I am lazy and don't like writing the same functions over and over, I used a Self reference so that all of my conforming models get this static function. Imagine my model is called "WhatsNew". Here's some code defining the protocol and the fetching function. protocol RemotelyFetchable: PersistentModel { var serverID: String { get } } extension WhatsNew: RemotelyFetchable {} extension RemotelyFetchable { static func fetchOne(withServerID identifier: String, inContext modelContext: ModelContext) -> Self? { var fetchDescriptor = FetchDescriptor<Self>() fetchDescriptor.predicate = #Predicate<Self> { $0.serverID == identifier } do { let allModels = try modelContext.fetch(fetchDescriptor) return allModels.first } catch { return nil } } } Worked great! Or so I thought... I built this and happily ran a debug build in the Simulator and on devices for months while developing the initial version but when I went to go do a release build for TestFlight, that build reliably crashed on every device with a message like this: SwiftData/DataUtilities.swift:65: Fatal error: Couldn't find \WhatsNew. on WhatsNew with fields [SwiftData.Schema.PropertyMetadata(name: "serverID", keypath: \WhatsNew., defaultValue: nil, metadata: Optional(Attribute - name: , options: [unique], valueType: Any, defaultValue: nil, hashModifier: nil)), SwiftData.Schema.PropertyMetadata(name: "title", keypath: \WhatsNew., defaultValue: nil, metadata: nil), SwiftData.Schema.PropertyMetadata(name: "bulletPoints", keypath: \WhatsNew.)>, defaultValue: nil, metadata: nil), SwiftData.Schema.PropertyMetadata(name: "dateDescription", keypath: \WhatsNew., defaultValue: nil, metadata: nil), SwiftData.Schema.PropertyMetadata(name: "readAt", keypath: \WhatsNew.)>, defaultValue: nil, metadata: nil)] It seems (cannot confirm) that something in the release build optimization process is stripping out some metadata / something about these models that makes this predicate crash. Tested on iOS 18.0 and 18.1 beta. How can I resolve this? I have two dozen types that conform to this protocol. I could manually specialize this function for every type myself but... ugh.
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2
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2
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1.6k
Activity
Oct ’25
Swiftdata cloudkit synchronization issues
Hi, I did cloudkit synchronization using swiftdata. However, synchronization does not occur automatically, and synchronization occurs intermittently only when the device is closed and opened. For confirmation, after changing the data in Device 1 (saving), when the data is fetched from Device 2, there is no change. I've heard that there's still an issue with swiftdata sync and Apple is currently troubleshooting it, is the phenomenon I'm experiencing in the current version normal?
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2
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1
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655
Activity
Oct ’25
Cloudkit dashboard won't load
For the past several days every time I log in to to the Cloudkit dashboard I get Error looking up Developer Teams, Please sign out and try again. No amount of singing out and back in changes anything.
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6
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2
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534
Activity
Nov ’25
SwiftData crash when using a @Query sort descriptor with a relationship
I am using SwiftData for storage and have a view that uses the @Query property wrapper with a sort descriptor that points to a relationship on a model. In a release build on device running iOS 18.3, the app crashes. This is the line that crashes: @Query(sort: \Item.info.endDate, order: .reverse) private var items: [Item] Item has a relationship to ItemInfo, which is where the endDate property is defined. This code works in debug and on a simulator. In the project referenced here: https://github.com/lepolt/swiftdata-crash, change the scheme build configuration to “Release” and run on device. The app will crash. Using Xcode Version 16.2 (16C5032a) iPhone 12, iOS 18.3 (22D60)
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9
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12
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1.6k
Activity
Aug ’25
CKSyncEngine: Duplicate FetchedRecordZoneChanges & Sync Handling Questions
Hi everyone, I've recently implemented CKSyncEngine in my app, and I have two questions regarding its behavior: Duplicate FetchedRecordZoneChanges After Sending Changes: I’ve noticed that the engine sometimes receives a FetchedRecordZoneChanges event containing modifications and deletions that were just sent by the same device a few moments earlier. This event arrives after the SentRecordZoneChanges event, and both events share the same recordChangeTag, which results in double-handling the record. Is this expected behavior? I’d like to confirm if this is how CKSyncEngine works or if I might be overlooking something. Handling Initial Sync with a "Sync Screen": When a user opens the app for the first time and already has data stored in iCloud, I need to display a "Sync Screen" temporarily to prevent showing partial data or triggering abrupt, rapid UI changes. I’ve found that canceling current operations, then awaiting sendChanges() and fetchChanges() works well to ensure data is fully synced before dismissing the sync screen: displaySyncScreen = true await syncEngine.cancelOperations() try await syncEngine.sendChanges() try await syncEngine.fetchChanges() displaySyncScreen = false However, I’m unsure if canceling operations like this could lead to data loss or other issues. Is this a safe approach, or would you recommend a better strategy for handling this initial sync state?
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2
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1
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1k
Activity
Apr ’26
SwiftData property marked ephemeral getting persisted in CloudKit
Am I misunderstanding the expected behavior here, or is there a bug in the behavior of @Attribute(.ephemeral) tagged SwiftData model properties? The documentation for .ephemeral says "Track changes to this property but do not persist". I started using .ephemeral because @Transient was inhibiting SwiftUI from reacting to changes to the property through @Observable. I am updating the value of my @Attribute(.ephemeral) property about once a second and I am seeing corresponding console log output showing the property as part of the generated CKRecord object. I then confirmed in the CloudKit dev portal that the .ephemeral property was added to the Record schema and contains real values. The behavior seems as though the .ephemeral property is being completely ignored. This is observed in a new Xcode project using SwiftData with CloudKit, Xcode 16.2, macOS 15.3.1 and during Build & Run testing on physical devices.
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3
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1.1k
Activity
Apr ’26
SwiftData migration error: NSCloudKitMirroringDelegate are not reusable
Hello everyone, I used SwiftData for v1 of an app and am now trying to make changes to the schema for v2. I created the v2 schema that adds a property to one of the models. I need to populate the new property so I made a custom migration using didMigrate. However that doesn't seem to matter what I do in the migration because creating the ModelContainer throws an error before didMigrate ever gets called. The error is: Unresolved error loading container Error Domain=NSCocoaErrorDomain Code=134060 "A Core Data error occurred." UserInfo={NSLocalizedFailureReason=Instances of NSCloudKitMirroringDelegate are not reusable and should have a lifecycle tied to a given instance of NSPersistentStore.} Higher up in the Xcode output I see things like this (in order): Request 'D25A8CB8-7341-4FA8-B2F8-3DE2D35B5273' was cancelled because the store was removed from the coordinator. BUG IN CLIENT OF CLOUDKIT: Registering a handler for a CKScheduler activity identifier that has already been registered CloudKit setup failed because it couldn't register a handler for the export activity. There is another instance of this persistent store actively syncing with CloudKit in this process. How can I know from this output what I am doing incorrectly? Any idea what I should take a look at or try to do differently? This is a simple app with three models and nothing fancy. The only change in the schema is to add a property. The new property is declared as optional and has an inverse that is also declared as optional. Thanks for any insight!
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16
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1.7k
Activity
Aug ’25
How to make a hidden iCloud Container active again?
While experimenting with CloudKit dashboard, I accidentally turned off a iCloud container. Now in the Certificates, Identifiers & Profiles section of developer portal, this iCloud container identifier is listed under "hidden" not "active" I can edit its name but there is not way to unhide or active it again. What am I missing?
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7
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0
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380
Activity
Nov ’25
Using relationships in SortDescriptor crashing on release
If use a SortDescriptor for a model and sort by some attribute from a relationship, in DEBUG mode it all works fine and sorts. However, in release mode, it is an instant crash. SortDescriptor(.name, order: .reverse) ---- works SortDescriptor(.assignedUser?.name, order: .reverse) ---- works in debug but crash in release. What is the issue here, is it that SwiftData just incompetent to do this?
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2
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133
Activity
Aug ’25
Core Data Multiple NSEntityDescriptions claim the NSManagedObject subclass
Hello everyone, I'm trying to adopt the new Staged Migrations for Core Data and I keep running into an error that I haven't been able to resolve. The error messages are as follows: warning: Multiple NSEntityDescriptions claim the NSManagedObject subclass 'Movie' so +entity is unable to disambiguate. warning: 'Movie' (0x60000350d6b0) from NSManagedObjectModel (0x60000213a8a0) claims 'Movie'. error: +[Movie entity] Failed to find a unique match for an NSEntityDescription to a managed object subclass This happens for all of my entities when they are added/fetched. Movie is an abstract entity subclass, and it has the error error: +[Movie entity] Failed to find which is unique to the subclass entities, but this occurs for all entities. The NSPersistentContainer is loaded only once, and I set the following option after it's loaded: storeDescription.setOption( [stages], forKey: NSPersistentStoreStagedMigrationManagerOptionKey ) The warnings and errors only appear after I fetch or save to context. It happens regardless of whether the database was migrated or not. In my test project, using the generic NSManagedObject with NSEntityDescription.insertNewObject(forEntityName: "MyEntity", into: context) does not cause the issue. However, using the generic NSManagedObject is not a viable option for my app. Setting the module to "Current Project Module" doesn't change anything, except that it now prints "claims 'MyModule.Show'" in the warnings. I have verified that there are no other entities with the same name or renameIdentifier. Has anyone else encountered this issue, or can offer any suggestions on how to resolve it? Thanks in advance for any help!
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342
Activity
2w
Does the CloudKit participant limit include the owner?
Does the CloudKit participant limit of 100 include the owner?
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1
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0
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135
Activity
Jun ’25
Fetching data with relationships directly faults the relationships even when not accessed
I am using SwiftData to model my data. For that i created a model called OrganizationData that contains various relationships to other entities. My data set is quite large and i am having a big performance issue when fetching all OrganizationData entities. I started debugging and looking at the sql debug log i noticed that when fetching my entities i run into faults for all relationships even when not accessing them. Fetching my entities: let fetchDescriptor = FetchDescriptor<OrganizationData>() let context = MapperContext(dataManager: self) let organizations = (try modelContainer.mainContext.fetch(fetchDescriptor)) Doing this fetch, also fetches all relationships. Each in a single query, for every OrganizationData entity. CoreData: annotation: to-many relationship fault "relationship1" for objectID 0x8aa5249772916e00 <x-coredata://B891FCEB-DF16-4E11-98E6-0AFB5D171A81/OrganizationData/p3869> fulfilled from database. Got 9 rows CoreData: annotation: to-many relationship fault "relationship2" for objectID 0x8aa5249772916e00 <x-coredata://B891FCEB-DF16-4E11-98E6-0AFB5D171A81/OrganizationData/p3869> fulfilled from database. Got 0 rows CoreData: annotation: to-many relationship fault "relationship3" for objectID 0x8aa5249772916e00 <x-coredata://B891FCEB-DF16-4E11-98E6-0AFB5D171A81/OrganizationData/p3869> fulfilled from database. Got 0 rows CoreData: annotation: to-many relationship fault "relationship4" for objectID 0x8aa5249772916e00 <x-coredata://B891FCEB-DF16-4E11-98E6-0AFB5D171A81/OrganizationData/p3869> fulfilled from database. Got 0 rows CoreData: annotation: to-many relationship fault "relationship5" for objectID 0x8aa5249772916e00 <x-coredata://B891FCEB-DF16-4E11-98E6-0AFB5D171A81/OrganizationData/p3869> fulfilled from database. Got 0 rows CoreData: annotation: to-many relationship fault "relationship6" for objectID 0x8aa5249772916e00 <x-coredata://B891FCEB-DF16-4E11-98E6-0AFB5D171A81/OrganizationData/p3869> fulfilled from database. Got 0 rows CoreData: annotation: to-many relationship fault "relationship7" for objectID 0x8aa5249772916e00 <x-coredata://B891FCEB-DF16-4E11-98E6-0AFB5D171A81/OrganizationData/p3869> fulfilled from database. Got 1 rows CoreData: annotation: to-many relationship fault "relationship8" for objectID 0x8aa5249772916e00 <x-coredata://B891FCEB-DF16-4E11-98E6-0AFB5D171A81/OrganizationData/p3869> fulfilled from database. Got 0 rows CoreData: annotation: to-many relationship fault "relationship9" for objectID 0x8aa5249772916e00 <x-coredata://B891FCEB-DF16-4E11-98E6-0AFB5D171A81/OrganizationData/p3869> fulfilled from database. Got 0 rows The relationships are all defined the same @Relationship(deleteRule: .cascade, inverse: \EntityData1.organization) var relationship1: [EntityData1] = [] Am i missing something? As far as i understood relationships are lazy and should only be faulted when accessing the property. But doing the fetch as described above already causes a query to happen, making the fetch take very long when using a large data set.
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14
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2
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470
Activity
Aug ’25
SwiftData 100% crash when fetching history with codable (test included!)
SwiftData crashes 100% when fetching history of a model that contains an optional codable property that's updated: SwiftData/Schema.swift:389: Fatal error: Failed to materialize a keypath for someCodableID.someID from CrashModel. It is possible that this path traverses a type that does not work with append(), please file a bug report with a test. Would really appreciate some help or even a workaround. Code: import Foundation import SwiftData import Testing struct VaultsSwiftDataKnownIssuesTests { @Test func testCodableCrashInHistoryFetch() async throws { let container = try ModelContainer( for: CrashModel.self, configurations: .init( isStoredInMemoryOnly: true ) ) let context = ModelContext(container) try SimpleHistoryChecker.hasLocalHistoryChanges(context: context) // 1: insert a new value and save let model = CrashModel() model.someCodableID = SomeCodableID(someID: "testid1") context.insert(model) try context.save() // 2: check history it's fine. try SimpleHistoryChecker.hasLocalHistoryChanges(context: context) // 3: update the inserted value before then save model.someCodableID = SomeCodableID(someID: "testid2") try context.save() // The next check will always crash on fetchHistory with this error: /* SwiftData/Schema.swift:389: Fatal error: Failed to materialize a keypath for someCodableID.someID from CrashModel. It is possible that this path traverses a type that does not work with append(), please file a bug report with a test. */ try SimpleHistoryChecker.hasLocalHistoryChanges(context: context) } } @Model final class CrashModel { // optional codable crashes. var someCodableID: SomeCodableID? // these actually work: //var someCodableID: SomeCodableID //var someCodableID: [SomeCodableID] init() {} } public struct SomeCodableID: Codable { public let someID: String } final class SimpleHistoryChecker { static func hasLocalHistoryChanges(context: ModelContext) throws { let descriptor = HistoryDescriptor<DefaultHistoryTransaction>() let history = try context.fetchHistory(descriptor) guard let last = history.last else { return } print(last) } }
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221
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3d
Migrating a swiftData project to CloudKit to implement iCloudSync.
My project is using swiftData and I want to implement iCloud sync in it. Now, my data base doesnt have any optional attributes or relationships and CloudKit wants them to be optional. So, rather than editing all code with unwrapping code for the optionals, how can I provide a bridge that does so in the last stage of actually saving to the store? Sort of, capture it in a proxy object before writing and after reading from the store. Is there a neat way that can save a lot of debugging? I have code snippets from chat gpt and they are hard to debug. This is my first project in swiftUI. Thanks. Neerav
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3
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0
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287
Activity
Jun ’25
CKSyncEngine on macOS: Automatic Fetch Extremely Slow Compared to iOS
Hi everyone, We’re currently using CKSyncEngine to sync all our locally persisted data across user devices (iOS and macOS) via iCloud. We’ve noticed something strange and reproducible: On iOS, when the CKSyncEngine is initialized with manual sync behavior, both manual calls to fetchChanges() and sendChanges() happen nearly instantly (usually within seconds). Automatic syncing is also very fast. On macOS, when the CKSyncEngine is initialized with manual sync behavior, fetchChanges() and sendChanges() are also fast and responsive. However, once CKSyncEngine is initialized with automatic syncing enabled on macOS: sendChanges() still appears to transmit changes immediately. But automatic fetching becomes significantly slower — often taking minutes to pick up changes from the cloud, even when new data is already available. Even manual calls to fetchChanges() behave as if they’re throttled or delayed, rather than performing an immediate fetch. Our questions: Is this delay in automatic (and post-automatic manual) fetch behavior on macOS expected, or possibly a bug? Are there specific macOS constraints that impact CKSyncEngine differently than on iOS? Once CKSyncEngine has been initialized in automatic mode, is fetchChanges() no longer treated as a truly manual trigger? Is there a recommended workaround to enable fast sync behavior on macOS — for example, by sticking to manual sync configuration and triggering sync using a CKSubscription-based mechanism when remote changes occur? Any guidance, clarification, or experiences from other developers (or Apple engineers) would be greatly appreciated — especially regarding maintaining parity between iOS and macOS sync performance. Thanks in advance!
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1
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1
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186
Activity
Oct ’25
iCloud sync issues using NSPersistentCloudKitContainer for Core Data + CloudKit sync.
I have tried to set up iCloud sync. Despite fully isolating and resetting my development environment, the app fails with: NSCocoaErrorDomain Code=134060 (PersistentStoreIncompatibleVersionHashError) What I’ve done: Created a brand new CloudKit container Created a new bundle ID and app target Renamed the Core Data model file itself Set a new model version Used a new .sqlite store path Created a new .entitlements file with the correct container ID Verified that the CloudKit dashboard shows no records Deleted and reinstalled the app on a real device Also tested with “Automatically manage signing” and without Despite this, the error persists. I am very inexperienced and am not sure what my next step is to even attempt to fix this. Any guidance is apprecitated.
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1
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230
Activity
Jun ’25
No persistent stores error in SwiftData
I am following Apple's instruction to sync SwiftData with CloudKit. While initiating the ModelContainer, right after removing the store from Core Data, the error occurs: FAULT: NSInternalInconsistencyException: This NSPersistentStoreCoordinator has no persistent stores (unknown). It cannot perform a save operation.; (user info absent) I've tried removing default.store and its related files/folders before creating the ModelContainer with FileManager but it does not resolve the issue. Isn't it supposed to create a new store when the ModelContainer is initialized? I don't understand why this error occurs. Error disappears when I comment out the #if DEBUG block. Code: import CoreData import SwiftData import SwiftUI struct InitView: View { @Binding var modelContainer: ModelContainer? @Binding var isReady: Bool @State private var loadingDots = "" @State private var timer: Timer? var body: some View { VStack(spacing: 16) { Text("Loading\(loadingDots)") .font(.title2) .foregroundColor(.gray) } .padding() .onAppear { startAnimation() registerTransformers() let config = ModelConfiguration() let newContainer: ModelContainer 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.my-container-identifier") desc.cloudKitContainerOptions = opts // Load the store synchronously so it completes before initializing the // CloudKit schema. desc.shouldAddStoreAsynchronously = false if let mom = NSManagedObjectModel.makeManagedObjectModel(for: [Page.self]) { let container = NSPersistentCloudKitContainer(name: "Pages", 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) } } // let fileManager = FileManager.default // let sqliteURL = config.url // let urls: [URL] = [ // sqliteURL, // sqliteURL.deletingLastPathComponent().appendingPathComponent("default.store-shm"), // sqliteURL.deletingLastPathComponent().appendingPathComponent("default.store-wal"), // sqliteURL.deletingLastPathComponent().appendingPathComponent(".default_SUPPORT"), // sqliteURL.deletingLastPathComponent().appendingPathComponent("default_ckAssets") // ] // for url in urls { // try? fileManager.removeItem(at: url) // } } #endif newContainer = try ModelContainer(for: Page.self, configurations: config) // ERROR!!! } catch { fatalError(error.localizedDescription) } modelContainer = newContainer isReady = true } .onDisappear { stopAnimation() } } private func startAnimation() { timer = Timer.scheduledTimer( withTimeInterval: 0.5, repeats: true ) { _ in updateLoadingDots() } } private func stopAnimation() { timer?.invalidate() timer = nil } private func updateLoadingDots() { if loadingDots.count > 2 { loadingDots = "" } else { loadingDots += "." } } } import CoreData import SwiftData import SwiftUI @main struct MyApp: App { @State private var modelContainer: ModelContainer? @State private var isReady: Bool = false var body: some Scene { WindowGroup { if isReady, let modelContainer = modelContainer { ContentView() .modelContainer(modelContainer) } else { InitView(modelContainer: $modelContainer, isReady: $isReady) } } } }
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298
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May ’25
Default zone is not accessible in shared DB - cloudKit
I am trying to save to cloud kit shared database. The shared database does not allow zones to be set up. How do I save to sharedCloudDatabase without a zone? private func addItem(recordType: String, name: String) { let record = CKRecord(recordType: recordType) record[Constances.field.name] = name as CKRecordValue record[Constances.field.done] = false as CKRecordValue record[Constances.field.priority] = 0 as CKRecordValue CKContainer.default().sharedCloudDatabase.save(record) { [weak self] returnRecord, error in if let error = error { print("Error saving record: \(record[Constances.field.name] as? String ?? "No Name"): \n \(error)") return } } } The following error message prints out: Error saving record: Milk: &lt;CKError 0x15af87900: "Server Rejected Request" (15/2027); server message = "Default zone is not accessible in shared DB"; op = B085F7BA703D4A08; uuid = 87AEFB09-4386-4E43-81D7-971AAE8BA9E0; container ID = "iCloud.com.sfw-consulting.Family-List"&gt;
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1
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166
Activity
Jun ’25
Feedback/issues for SwiftData custom store
Hello, thank you Apple for supporting custom store with SwiftData and the Schema type is superb to work with. I have successfully set one up with SQL and have some feedback and issues regarding its APIs. There’s a highlighted message in the documentation about not using internal restricted symbols directly, but they contradict with the given protocols and I am concerned about breaking any App Store rules. Are we allowed to use these? If not, they should be opened up as they’re useful. BackingData is required to set up custom snapshots, initialization, and getting/setting values. And I want to use it with createBackingData() to directly initialize instances from snapshots when transferring them between server and client or concurrency. RelationshipCollection for casting to-many relationships from backing data or checking if an array contains a PersistentModel. SchemaProperty for type erasure in a collection. Schema.Relationship has KeyPath properties, but it is missing for Schema.Attribute and Schema.CompositeAttribute. Which means you can’t purely depend on the schema to map data. I am unable to access the properties of a custom struct type in a predicate unless I use Mirror with schemaMetadata() or CustomStringConvertible on the KeyPath directly to extract it. Trivial, but… the KeyPath property name is inconsistent (it’s all lowercase). It would be nice to retrieve property names from custom struct types, since you are unable access CodingKeys that are auto synthesized by Codable for structs. But I recently realized they’re a part Schema.CompositeAttribute, however I don’t know how to match these without the KeyPath… I currently map my entities using CodingKeys to their PredicateCodableKeyPathProviding.… but I wish for a simpler alternative! It’s unclear how to provide the schema to the snapshot before new models are created. I currently use a static property, but I want to make it flexible if more schemas and configurations are added later on. I considered saving and loading the schema in a temporary location, but doubtful that the KeyPath values will be available as they are not Codable. I suspect schemaMetadata() has the information I need to map the backing data without a schema for snapshots, but as mentioned previously, properties are inaccessible… Allow access to entity metatypes, like value types from SchemaProperty. They’re useful for getting data out of snapshots and casting them to CodingKeys and PredicateCodableKeyPathProviding. They do not carry over when you provide them in the Schema. I am unable to retrieve the primary key from PersistentIdentifier. It seems like once you create one, you can’t get it out, like the DataStoreConfiguration in ModelContainer is not the one you used to set it up. I cannot cast it, it is an entirely different struct? I have to use JSONSerialization to extract it, but I want to get it directly since it is not a column in my database. It is transformed when it goes to/from my tables. It’s unknown how to support some schema options, such as Spotlight and CloudKit. Allow for extending macro options, such as adding options to set as primary key, whether to auto increment, etc… You can create a schema for super and sub entities, but it doesn’t appear you can actually set them up from the @Model macro or use inheritance on these models… SwiftData history tracking seems incomplete for HistoryDelete, because that protocol requires HistoryTombstone, but this type cannot be instantiated, nor does it contain anything useful to infer from. As an aside, I want to create my own custom ModelActor that is a global actor. However, I’m unable to replicate the executor that Apple provides where the executor has a ModelContext, because this type does not conform to Sendable. So how did Apple do this? The documentation doesn’t mention unchecked Sendable, but I figure if the protocol is available then we would be able to set up our own. And please add concurrency features! Anyway, I hope for more continued support in the future and I am looking forward to what’s new this WWDC! 😊
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207
Activity
May ’25