Hi, I am currently experiencing some trouble when using parent model property in a predicate of a child model. I have an Item class that define parent-child relationship: @Model class Item { var timestamp: Date @Relationship(inverse: \Item.children) var parent: Item? var children: [Item] init(parent: Item? = nil, children: [Item] = [], timestamp: Date = .now) { self.parent = parent self.children = children self.timestamp = timestamp } } I subclass this model like that: @available(iOS 26, *) @Model final class CollectionItem: Item { /* ... */ } When i make a Query in my View like that the system crashes: @Query( filter: #Predicate<CollectionItem> { $0.parent == nil }, sort: \CollectionItem.name, ) private var collections: [CollectionItem] CrashReportError: Fatal Error in DataUtilities.swift AppName crashed due to fatalError in DataUtilities.swift at line 85. Couldn't find \CollectionItem.<computed 0x000000034005d4e8 (Optional<Item>)> on CollectionItem with fields [SwiftData.Schema.PropertyMetadata(name: "name", keypath: \CollectionItem.<computed 0x000000034003c120 (String)>, defaultValue: nil, metadata: nil), SwiftData.Schema.PropertyMetadata(name: "icon", keypath: \CollectionItem.<computed 0x000000034003ca04 (Optional<String>)>, defaultValue: nil, metadata: nil), SwiftData.Schema.PropertyMetadata(name: "timestamp", keypath: \Item.<computed 0x0000000340048018 (Date)>, defaultValue: nil, metadata: nil), SwiftData.Schema.PropertyMetadata(name: "parent", keypath: \Item.<computed 0x0000000340048a4c (Optional<Item>)>, defaultValue: nil, metadata: Optional(Relationship - name: , options: [], valueType: Any, destination: , inverseName: nil, inverseKeypath: Optional(\Item.<computed 0x0000000340048fe8 (Array<Item>)>))), SwiftData.Schema.PropertyMetadata(name: "children", keypath: \Item.<computed 0x0000000340048fe8 (Array<Item>)>, defaultValue: nil, metadata: nil)] When I query as Item it works but then i cannot sort on CollectionItem field and must add unnecessary down casting: @Query( filter: #Predicate<Item> { $0.parent == nil && $0 is CollectionItem }, ) private var items: [Item] Am I missing something? Is it a platform limitation or a known issue?

This simple test fails in my project. Similar code in my application also crashes. How do I debug the problem? What project settings are required. I have added SwiftData as a framework to test (and application) targets? Thanks, The problem is with: modelContext.insert(item) Thread 1: EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0) import XCTest import SwiftData @Model class FakeModel { var name: String init(name: String) { self.name = name } } @MainActor final class FakeModelTests: XCTestCase { var modelContext: ModelContext! override func setUp() { super.setUp() do { let container = try ModelContainer(for: FakeModel.self, configurations: ModelConfiguration(isStoredInMemoryOnly: true)) modelContext = container.mainContext } catch { XCTFail("Failed to create ModelContainer: \(error)") modelContext = nil } } func testSaveFetchDeleteFakeItem() { guard let modelContext = modelContext else { XCTFail("ModelContext must be initialized") return } let item = FakeModel(name: "Test") modelContext.insert(item) let fetchDescriptor = FetchDescriptor<FakeModel>() let items = try! modelContext.fetch(fetchDescriptor) XCTAssertEqual(items.count, 1) XCTAssertEqual(items.first?.name, "Test") modelContext.delete(item) let itemsAfterDelete = try! modelContext.fetch(fetchDescriptor) XCTAssertEqual(itemsAfterDelete.count, 0) } }

I have the following lines of code to access data through CoreData. import Foundation import CoreData import CloudKit class CoreDataManager { static let instance = CoreDataManager() let container: NSPersistentCloudKitContainer let context: NSManagedObjectContext init() { container = NSPersistentCloudKitContainer(name: "ABC") container.loadPersistentStores(completionHandler: { (storeDescription, error) in if let error = error as NSError? { print(error.userInfo) } }) context = container.viewContext context.automaticallyMergesChangesFromParent = true context.mergePolicy = NSMergePolicy(merge: .mergeByPropertyObjectTrumpMergePolicyType) } func save() { do { try container.viewContext.save() print("Saved successfully") } catch { print("Error in saving data: \(error.localizedDescription)") } } } I have confirmed that I can share data between iPhone and iPad. Now, I need to use AppGroup as well. I have changed my code as follows. import Foundation import CoreData import CloudKit class CoreDataManager { static let shared = CoreDataManager() let container: NSPersistentContainer let context: NSManagedObjectContext init() { container = NSPersistentCloudKitContainer(name: "ABC") container.persistentStoreDescriptions = [NSPersistentStoreDescription(url: FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: "some group name")!.appendingPathComponent("CoreDataMama.sqlite"))] container.loadPersistentStores(completionHandler: { (description, error) in if let error = error as NSError? { print("Unresolved error \(error), \(error.userInfo)") } }) context = container.viewContext context.automaticallyMergesChangesFromParent = true context.mergePolicy = NSMergePolicy(merge: .mergeByPropertyObjectTrumpMergePolicyType) } func save() { do { try container.viewContext.save() print("Saved successfully") } catch { print("Error in saving data: \(error.localizedDescription)") } } } Other files being unaltered, my sample apps aren't sharing data. What am I doing wrong? Just FYI, I'm using actual devices. Thank you for your reading this topic.

Hi, I’m running into an issue with Core Data migrations using a custom NSMappingModel created entirely in Swift (not using .xcmappingmodel files). Setup: • I’m performing a migration with a manually constructed NSMappingModel • One of the NSEntityMapping instances is configured as follows: • mappingType = .customEntityMappingType (or .transformEntityMappingType) • entityMigrationPolicyClassName is set to a valid subclass of NSEntityMigrationPolicy • The class implements the expected methods like: @objc func createDestinationInstances(…) throws { … } @objc func createCustomDestinationInstance(…) throws -> NSManagedObject { … } The policy class is instantiated (confirmed via logging in init()), but none of the migration methods are ever called. I have also tried adding valid NSPropertyMapping instances with real valueExpression bindings to force activation, but that didn’t make a difference. Constraints: • I cannot use .xcmappingmodel files in this context due to transformable attributes not compatible with the visual editor. • Therefore, I need the entire mapping model to be defined in Swift. Workaround: As a temporary workaround, I’m migrating the data manually using two persistent stores and NSManagedObjectContext, but I’d prefer to rely on NSMigrationManager as designed. Question: Is there a known limitation that prevents Core Data from invoking NSMigrationPolicy methods when using in-memory NSMappingModel instances? Or is there any specific setup required to trigger them when not loading from .xcmappingmodel? Thanks in advance.

If I use <FetchRequest.returnsDistinctResults> with unique "identifier" property, and there happened to be multiple NSManagedObjects in Core Data that contains the same "identifier", does the FetchRequest retrieve the latest modified/created object? Is there a way to define the <FetchRequest.returnsDistinctResults> logic to be based on another property (e.g. "creationDate" / "modifiedDate") and the ascension order?

Some of my customer get the following CloudKit error (I cannot reproduce is myself). Failed to modify some records (CKErrorDomain:2) userInfo: CKErrorDescription:Failed to modify some records CKPartialErrors:{ "<CKRecordID: ooo; recordName=ooo, zoneID=ooo:__defaultOwner__>" = "<CKError 0x600003809ce0: \"Limit Exceeded\" (27/2023); server message = \"AssetUploadTokenRetrieveRequest request size exceeds limit\"; op = ooo; uuid = ooo; container ID = \"ooo\">" This is a CKError.limitExeeded error. I create 200 or less records in a batch operation. So I am below the 400 limit. Searching the Internet for "AssetUploadTokenRetrieveRequest request size exceeds limit": 0 results Can anyone give me a hint?

Users have been reporting that the TestFlight version of my app (compiled with Xcode 26 Beta 6 17A5305f) is sometimes crashing on startup. Upon investigating their ips files, it looks like Core Data is locking up internally during its initialization, resulting in iOS killing my app. I have not recently changed my Core Data initialization logic, and it's unclear how I should proceed. Is this a known issue? Any recommended workaround? I have attached the crash stack below. Thanks! crash_log.txt

Hi everyone, I’ve been working on migrating my app (SwimTimes, which helps swimmers track their times) to use Core Data + CKSyncEngine with Swift 6. After many iterations, forum searches, and experimentation, I’ve created a focused sample project that demonstrates the architecture I’m using. The good news: 👉 I believe the crashes I was experiencing are now solved, and the sync behavior is working correctly. 👉 The demo project compiles and runs cleanly with Swift 6. However, before adopting this as the final architecture, I’d like to ask the community (and hopefully Apple engineers) to validate a few critical points, especially regarding Swift 6 concurrency and Core Data contexts. Architecture Overview Persistence layer: Persistence.swift sets up the Core Data stack with a main viewContext and a background context for CKSyncEngine. Repositories: All Core Data access is abstracted into repository classes (UsersRepository, SwimTimesRepository), with async/await methods. SyncEngine: Wraps CKSyncEngine, handles system fields, sync tokens, and bridging between Core Data entities and CloudKit records. ViewModels: Marked @MainActor, exposing @Published arrays for SwiftUI. They never touch Core Data directly, only via repositories. UI: Simple SwiftUI views bound to the ViewModels. Entities: UserEntity → represents swimmers. SwimTimeEntity → times linked to a user (1-to-many). Current Status The project works and syncs across devices. But there are two open concerns I’d like validated: Concurrency & Memory Safety Am I correctly separating viewContext (main/UI) vs. background context (used by CKSyncEngine)? Could there still be hidden risks of race conditions or memory crashes that I’m not catching? Swift 6 Sendable Compliance Currently, I still need @unchecked Sendable in the SyncEngine and repository layers. What is the recommended way to fully remove these workarounds and make the code safe under Swift 6’s stricter concurrency rules? Request Please review this sample project and confirm whether the concurrency model is correct. Suggest how I can remove the @unchecked Sendable annotations safely. Any additional code improvements or best practices would also be very welcome — the intention is to share this as a community resource. I believe once finalized, this could serve as a good reference demo for Core Data + CKSyncEngine + Swift 6, helping others migrate safely. Environment iOS 18.5 Xcode 16.4 macOS 15.6 Swift 6 Sample Project Here is the full sample project on GitHub: 👉 [https://github.com/jarnaez728/coredata-cksyncengine-swift6] Thanks a lot for your time and for any insights! Best regards, Javier Arnáez de Pedro

As of 2025-05-03, when a macOS user enables iCloud Drive synchronization for Desktop &amp; Documents in US region, does iCloud filter xattrs upon upload or later when downloading back to another macOS host? Or is it the case that iCloud has no filtering of third-party xattrs? Where can I find the technical document outlining exactly what iCloud does with xattrs set on macOS host files and folders synchronized with iCloud Drive?

My entity has a startDate (NSTime) attribute where I use the date and time in my detail display of the entity. And in my list, I need to group my entities by day (YYMMDD) based on the start date; and I want to ensure that it can adapt to the region where the user is currently (e.g. if user travels or migrate, the YYMMDD should be adapted based on the current region). Does Core Data SectionedFetchRequest supports strftime() functions from SQLite (https://sqlite.org/lang_datefunc.html) or what is an effective alternative sectioned fetch in my case?

I'm a first time developer for Swift, (getting on a bit!) but after programming in VB back in the late 90s I wanted to write an app for iPhone. I think I might have gone about it the wrong way, but I've got an app that works great on my iPhone or works great on my iPad. It saves the data persistently on device, but, no matter how much I try, what I read and even resorting to AI (ChatGPT & Gemini) I still can't get it to save the data on iCloud to synchronise between the two and work across the devices. I think it must be something pretty fundamental I'm doing (or more likely not doing) that is causing the issue. I'm setting up my signing and capabilities as per the available instructions but I always get a fatal error. I think it might be something to do with making fields optional, but at this point I'm second guessing myself and feeling a complete failure. Any advice or pointers would be really gratefully appreciated. I like my app and would like eventually to get it on the App Store but at this point in time I feel it should be on the failed projects heap! I've even tried a new Xcode project for iOS and asking it to use SwiftData and CloudKit - the default project should work - right? But it absolutely doesn't for me. Please send help!!

I am trying to extend my PersistedModels like so: @Versioned(3) @Model class MyType { var name: String init() { name = "hello" } } but it seems that SwiftData's@Model macro is unable to read the properties added by my @Versioned macro. I have tried changing the order and it ignores them regardless. version is not added to schemaMetadata and version needs to be persisted. I was planning on using this approach to add multiple capabilities to my model types. Is this possible to do with macros? VersionedMacro /// A macro that automatically implements VersionedModel protocol public struct VersionedMacro: MemberMacro, ExtensionMacro { // Member macro to add the stored property directly to the type public static func expansion( of node: AttributeSyntax, providingMembersOf declaration: some DeclGroupSyntax, in context: some MacroExpansionContext ) throws -> [DeclSyntax] { guard let argumentList = node.arguments?.as(LabeledExprListSyntax.self), let firstArgument = argumentList.first?.expression else { throw MacroExpansionErrorMessage("@Versioned requires a version number, e.g. @Versioned(3)") } let versionValue = firstArgument.description.trimmingCharacters(in: .whitespaces) // Add the stored property with the version value return [ "public private(set) var version: Int = \(raw: versionValue)" ] } // Extension macro to add static property public static func expansion( of node: SwiftSyntax.AttributeSyntax, attachedTo declaration: some SwiftSyntax.DeclGroupSyntax, providingExtensionsOf type: some SwiftSyntax.TypeSyntaxProtocol, conformingTo protocols: [SwiftSyntax.TypeSyntax], in context: some SwiftSyntaxMacros.MacroExpansionContext ) throws -> [SwiftSyntax.ExtensionDeclSyntax] { guard let argumentList = node.arguments?.as(LabeledExprListSyntax.self), let firstArgument = argumentList.first?.expression else { throw MacroExpansionErrorMessage("@Versioned requires a version number, e.g. @Versioned(3)") } let versionValue = firstArgument.description.trimmingCharacters(in: .whitespaces) // We need to explicitly add the conformance in the extension let ext = try ExtensionDeclSyntax("extension \(type): VersionedModel {}") .with(\.memberBlock.members, MemberBlockItemListSyntax { MemberBlockItemSyntax(decl: DeclSyntax( "public static var version: Int { \(raw: versionValue) }" )) }) return [ext] } } VersionedModel public protocol VersionedModel: PersistentModel { /// The version of this particular instance var version: Int { get } /// The type's current version static var version: Int { get } } Macro Expansion:

I am developing an app that uses CloudKit sharing. I recently upgraded my iPad to use 23A5336a. After that upgrade, I can no longer accept a share that is sent to me. I have rebooted the iPad and logged out of the iCloud account and logged back in. Every time I get a share link and tap it, it says: " The owner stopped sharing or your account (xxx) doesn't have permission to open it" This same code, running on the iOS26 device can share with device running iOS18. Is this a known defect? Anything I can do to help resolve this issue?

I'm trying to set up an application using SwiftData to have a number of models backed by a local datastore that's not synced to CloudKit, and another set of models that is. I was able to achieve this previously with Core Data using multiple NSPersistentStoreDescription instances. The set up code looks something like: do { let fullSchema = Schema([ UnsyncedModel.self, SyncedModel.self, ]) let localSchema = Schema([UnsyncedModel.self]) let localConfig = ModelConfiguration(schema: localSchema, cloudKitDatabase: .none) let remoteSchema = Schema([SyncedModel.self]) let remoteConfig = ModelConfiguration(schema: remoteSchema, cloudKitDatabase: .automatic) container = try ModelContainer(for: fullSchema, configurations: localConfig, remoteConfig) } catch { fatalError("Failed to configure SwiftData container.") } However, it doesn't seem to work as expected. If I remove the synced/remote schema and configuration then everything works fine, but the moment I add in the remote schema and configuration I get various different application crashes. Some examples below: A Core Data error occurred." UserInfo={Reason=Entity named:... not found for relationship named:..., Fatal error: Failed to identify a store that can hold instances of SwiftData._KKMDBackingData<...> Has anyone ever been able to get a similar setup to work using SwiftData?

This is probably super simple answer that I missed, but: I have an app that has a database; I'd like to create a second app (actually a CLI tool), and access the same database. Is that possible? And, if so, how? 😄

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?

I'm working on a new app with SwiftData and now adding CloudKit Sync. Everything is working fine in the simulator against the development CloudKit Schema. I successfully deployed the schema to production. However, the TestFlight builds fail against production. This is what I see in the logs, but I haven't been able to find info on how to fix it. Help appreciated. CoreData+CloudKit: -[NSCloudKitMirroringDelegate _requestAbortedNotInitialized:](2205): <private> - Never successfully initialized and cannot execute request '<private>' due to error: Error Domain=CKErrorDomain Code=2 "CKInternalErrorDomain: 1011" UserInfo={ContainerID=<private>, NSDebugDescription=CKInternalErrorDomain: 1011, CKPartialErrors=<private>, RequestUUID=<private>, NSLocalizedDescription=<private>, CKErrorDescription=<private>, NSUnderlyingError=0x1078e9fe0 {Error Domain=CKInternalErrorDomain Code=1011 UserInfo={CKErrorDescription=<private>, NSLocalizedDescription=<private>, CKPartialErrors=<private>}}} CoreData+CloudKit: -[NSCloudKitMirroringDelegate _performSetupRequest:]_block_invoke(1153): <private>: Successfully set up CloudKit integration for store (<private>): <private> CoreData+CloudKit: -[NSCloudKitMirroringDelegate _enqueueRequest:]_block_invoke(1035): Failed to enqueue request: <private> Error Domain=NSCocoaErrorDomain Code=134417 UserInfo={NSLocalizedFailureReason=<private>}

Hi everyone, Complete newbie here. Building an app and trying to use Cloudkit. I've added the CloudKit capability, triple checked the entitlements file for appropriate keys, made sure the code signing entitlements are pointing to the correct entitlements file. I've removed and cleared all of those settings and even created a new container as well as refreshed the signing. I just can't seem to figure out why I keep getting this error: Significant issue at CKContainer.m:747: In order to use CloudKit, your process must have a com.apple.developer.icloud-services entitlement. The value of this entitlement must be an array that includes the string "CloudKit" or "CloudKit-Anonymous". Any guidance is greatly appreciated.

Hello, I have an asset pack that I'm use to periodically distribute a sqlite database thats being used to an NSPersistentStore. Because the database is over a few GBs, and the files in an AssetPack are not mutable, I have to stream the database into a temporary file, then replace my NSPersistentStore. This requires that the user has 3x the storage available of the database, and permanently uses twice to storage needed. I'd like: To be able to mark a URL/File to be accessible for read/write access To be able to mark a file / URL as consumed when it's no needed. So that it can be cleared from the user storage while still maintaining an active subscription to the asset pack for updates. Thank you

I have a simple app that makes an HTTPS call to gather some JSON which I then parse and add to my SwiftData database. The app then uses a simple @Query in a view to get the data into a list. on iOS 16 this works fine. No problems. But the same code on iOS 26 (targeting iOS 18.5) crashes after about 15 seconds of idle time after the list is populated. The error message is: Could not cast value of type '__NSCFNumber' (0x1f31ee568) to 'NSString' (0x1f31ec718). and occurs when trying to access ANY property of the list. I have a stripped down version of the app that shows the crash available. To replicate the issue: open the project in Xcode 26 target any iOS 26 device or simulator compile and run the project. after the list is displayed, wait about 15 seconds and the app crashes. It is also of note that if you try to run the app again, it will crash immediately, unless you delete the app from the device. Any help on this would be appreciated. Feedback number FB20295815 includes .zip file Below is the basic code (without the data models) The Best Seller List.Swift import SwiftUI import SwiftData @main struct Best_Seller_ListApp: App { var body: some Scene { WindowGroup { ContentView() } .modelContainer (for: NYTOverviewResponse.self) } } ContentView.Swift import os.log import SwiftUI struct ContentView: View { @Environment(\.modelContext) var modelContext @State private var listEncodedName = String() var body: some View { NavigationStack () { ListsView() } .task { await getBestSellerLists() } } func getBestSellerLists() async { guard let url = URL(string: "https://api.nytimes.com/svc/books/v3/lists/overview.json?api-key=\(NYT_API_KEY)") else { Logger.errorLog.error("Invalid URL") return } do { let decoder = JSONDecoder() var decodedResponse = NYTOverviewResponse() //decode the JSON let (data, _) = try await URLSession.shared.data(from: url) decoder.keyDecodingStrategy = .convertFromSnakeCase decodedResponse = try decoder.decode(NYTOverviewResponse.self, from: data) //remove any lists that don't have list_name_encoded. Fixes a bug in the data decodedResponse.results!.lists = decodedResponse.results!.lists!.filter { $0.listNameEncoded != "" } // sort the lists decodedResponse.results!.lists!.sort { (lhs, rhs) -> Bool in lhs.displayName < rhs.displayName } //delete any potential existing data try modelContext.delete(model: NYTOverviewResponse.self) //add the new data modelContext.insert(decodedResponse) } catch { Logger.errorLog.error("\(error.localizedDescription)") } } } ListsView.Swift import os.log import SwiftData import SwiftUI @MainActor struct ListsView: View { //MARK: - Variables and Constants @Query var nytOverviewResponses: [NYTOverviewResponse] enum Updated: String { case weekly = "WEEKLY" case monthly = "MONTHLY" } //MARK: - Main View var body: some View { List { if nytOverviewResponses.isEmpty { ContentUnavailableView("No lists yet", systemImage: "list.bullet", description: Text("NYT Bestseller lists not downloaded yet")) } else { WeeklySection MonthlySection } } .navigationBarTitle("Bestseller Lists", displayMode: .large) .listStyle(.grouped) } var WeeklySection: some View { let rawLists = nytOverviewResponses.last?.results?.lists ?? [] // Build a value-typed array to avoid SwiftData faulting during sort let weekly = rawLists .filter { $0.updateFrequency == Updated.weekly.rawValue } .map { (name: $0.displayName, encoded: $0.listNameEncoded, model: $0) } .sorted { $0.name < $1.name } return Section(header: Text("Weekly lists to be published on \(nytOverviewResponses.last?.results?.publishedDate ?? "-")")) { ForEach(weekly, id: \.encoded) { item in Text(item.name).font(Font.custom("Georgia", size: 17)) } } } var MonthlySection: some View { let rawLists = nytOverviewResponses.last?.results?.lists ?? [] // Build a value-typed array to avoid SwiftData faulting during sort let monthly = rawLists .filter { $0.updateFrequency == Updated.monthly.rawValue } .map { (name: $0.displayName, encoded: $0.listNameEncoded, model: $0) } .sorted { $0.name < $1.name } return Section(header: Text("Monthly lists to be published on \(nytOverviewResponses.last?.results?.publishedDate ?? "-")")) { ForEach(monthly, id: \.encoded) { item in Text(item.name).font(Font.custom("Georgia", size: 17)) } } } }