Starting 20th March 2025, I see an increase in bandwidth and latency for one of my CloudKit projects. I'm using NSPersistentCloudKitContainer to synchronise my data. I haven't changed any CloudKit scheme during that time but shipped an update. Since then, I reverted some changes from that update, which could have led to changes in the sync behaviour. Is anyone else seeing any issues? I would love to file a DTS and use one of my credits for that, but unfortunately, I can't because I cannot reproduce it with a demo project because I cannot travel back in time and check if it also has an increase in metrics during that time. Maybe an Apple engineer can green-light me filing a DTS request, please.

Hello, In my iOS/SwiftUI/SwiftData app, I want the user to be able to hit [Cancel] from editing in a detail screen and return to the previous screen without changes being saved. I believed that setting autosaveEnabled to false and/or calling .rollback would prevent changes from being saved, unless/until I call .save() when the user clicks [Save], but this does not seem to be correct. I set modelContext.autosaveEnabled = false and I call modelContext.rollback() when the user hits [Cancel], but any changes they made are not rolled back, but saved even if I don’t call save(). I have tried setting autosaveEnabled to false when I create the ModelContainer on a @MainActor function when the App starts, and in the detail/edit screen’s .onAppear(). I can see that .rollback is being called when the [Cancel] button is tapped. In all cases, any changes the user made before hitting [Cancel] are saved. The Developer Documentation on autosaveEnabled includes this: “The default value is false. SwiftData automatically sets this property to true for the model container’s mainContext." I am working on the mainContext, but it appears that setting autosaveEnabled to false has no effect no matter where in the code I set it. If someone sees what I am doing wrong, I’d sure appreciate the input. If this description doesn’t explain the problem well enough, I’ll develop a minimal focused example.

I am a novice developer, so please be kind. 😬 I am developing a simple macOS app backed with SwiftData and trying to set up iCloud sync so data syncs between two Macs running the app. I have added the iCloud capability, checked the CloudKit box, and selected an iCloud Container. Per suggestion of Paul Hudson, my model properties have either default values or are marked as optional, and the only relationship in my model is marked as optional. @Model final class Project { // Stable identifier used for restoring selected project across launches. var uuid: UUID? var name: String = "" var active: Bool = true var created: Date = Foundation.Date(timeIntervalSince1970: 0) var modified: Date = Foundation.Date(timeIntervalSince1970: 0) // CloudKit requires to-many relationships to be optional in this schema. @Relationship var timeEntries: [TimeEntry]? init(name: String, active: Bool = true, uuid: UUID? = UUID()) { self.uuid = uuid self.name = name self.active = active self.created = .now self.modified = .now self.timeEntries = [] } @Model final class TimeEntry { // Core timing fields. var start: Date = Foundation.Date(timeIntervalSince1970: 0) var end: Date = Foundation.Date(timeIntervalSince1970: 0) var codeRawValue: String? var activitiesRawValue: String = "" // Inverse relationship back to the owning project. @Relationship(inverse: \Project.timeEntries) var project: Project? init( start: Date = .now, end: Date = .now.addingTimeInterval(60 * 60), code: BillingCode? = nil, activities: [ActivityType] = [] ) { self.start = start self.end = end self.codeRawValue = code?.rawValue self.activitiesRawValue = Self.serializeActivities(activities) } I have set up the following in the AppDelegate for registering for remote notifications as well as some logging to console that the remote notification token was received and to be notified when when I am receiving remote notifications. private final class TimeTrackerAppDelegate: NSObject, NSApplicationDelegate { func applicationDidFinishLaunching(_ notification: Notification) { print("📡 [Push] Registering for remote notifications") NSApplication.shared.registerForRemoteNotifications() } func application(_ application: NSApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) { let tokenPreview = deviceToken.map { String(format: "%02x", $0) }.joined().prefix(16) print("✅ [Push] Registered for remote notifications (token prefix: \(tokenPreview)...)") } func application(_ application: NSApplication, didFailToRegisterForRemoteNotificationsWithError error: Error) { let nsError = error as NSError print("❌ [Push] Failed to register for remote notifications: \(nsError.domain) (\(nsError.code)) \(nsError.localizedDescription)") } func application(_ application: NSApplication, didReceiveRemoteNotification userInfo: [String: Any]) { print("📬 [Push] Received remote notification: \(userInfo)") } } In testing, I run the same commit from Xcode on two different Macs logged into the same iCloud account. My problem is that sync is not reliably working. Starting up the app on both Macs shows that the app successfully registered for remote notifications. Sometimes, making an edit on Mac 1 is immediately reflected in Mac 2 UI along with didReceiveRemoteNotification message (all occurring while the Mac 2 app remains in foreground). Sometimes, the Mac 2 app needs to be backgrounded and re-foregrounded before the UI shows the updated data. Sometimes, an edit on Mac 2 will show on Mac 1 only after re-foregrounded but not show any didReceiveRemoteNotification on the Mac 1 console. Sometimes, an edit on Mac 2 will not show at all on Mac 1 even after re-foregrounding the app. Sometimes, no edits sync between either Mac. I had read about how a few years back, there was a bug in macOS where testing iCloud sync between Macs did not work while running from Xcode but would work in TestFlight. For me, running my app in TestFlight on both Macs has never been able to sync any edits between the Macs. Any idea where I might be going wrong. It seems this should not be this hard and should not be failing so inconsistently. Wondering what I might be doing wrong here.

I'm getting the following error message when executing the rollback method in a modelContext, what could be causing this ? SwiftData/ModelSnapshot.swift:46: Fatal error: A ModelSnapshot must be initialized with a known-keys dictionary

I am working on a SwiftUI project using Core Data. I have an entity called AppleUser in my data model, with the following attributes: id (UUID), name (String), email (String), password (String), and createdAt (Date). All attributes are non-optional. I created the corresponding Core Data class files (AppleUser+CoreDataClass.swift and AppleUser+CoreDataProperties.swift) using Xcode’s automatic generation. I also have a PersistenceController that initializes the NSPersistentContainer with the model name JobLinkModel. When I try to save a new AppleUser object using: let user = AppleUser(context: viewContext) user.id = UUID() user.name = "User1" user.email = "..." user.password = "password1" user.createdAt = Date()【The email is correctly formatted, but it has been replaced with “…” for privacy reasons】 try? viewContext.save() I get the following error in the console:Core Data save failed: Foundation._GenericObjCError.nilError, [:] User snapshot: ["id": ..., "name": "User1", "email": "...", "password": "...", "createdAt": ...] All fields have valid values, and the Core Data model seems correct. I have also tried: • Checking that the model name in NSPersistentContainer(name:) matches the .xcdatamodeld file (JobLinkModel) • Ensuring the AppleUser entity Class, Module, and Codegen are correctly set (Class Definition, Current Product Module) • Deleting duplicate or old AppleUser class files • Cleaning Xcode build folder and deleting the app from the simulator • Using @Environment(.managedObjectContext) for the context Despite all this, I still get _GenericObjCError.nilError when saving a new AppleUser object. I want to understand: 1. Why is Core Data failing to save even though all fields are non-nil and correctly assigned? 2. Could this be caused by some residual old class files, or is there something else in the setup that I am missing? 3. What steps should I take to ensure that Core Data properly recognizes the AppleUser entity and allows saving? Any help or guidance would be greatly appreciated.

Hello Apple Team, We’re building a CloudKit-enabled Core Data app and would like clarification on the behavior and performance characteristics of Binary Data attributes with “Allows External Storage” enabled when used with NSPersistentCloudKitContainer. Initially, we tried storing image files manually on disk and only saving the metadata (file URLs, dimensions, etc.) in Core Data. While this approach reduced the size of the Core Data store, it introduced instability after app updates and broke sync between devices. We would prefer to use the official Apple-recommended method and have Core Data manage image storage and CloudKit syncing natively. Specifically, we’d appreciate guidance on the following: When a Binary Data attribute is marked as “Allows External Storage”, large image files are stored as separate files on device rather than inline in the SQLite store. How effective is this mechanism in keeping the Core Data store size small on device? Are there any recommended size thresholds or known limits for how many externally stored blobs can safely be managed this way? How are these externally stored files handled during CloudKit sync? Does each externally stored Binary Data attribute get mirrored to CloudKit as a CKAsset? Does external storage reduce the sync payload size or network usage, or is the full binary data still uploaded/downloaded as part of the CKAsset? Are there any bandwidth implications for users syncing via their private CloudKit database, versus developer costs in the public CloudKit database? Is there any difference in CloudKit or Core Data behavior when a Binary Data attribute is managed this way versus manually storing image URLs and handling the file separately on disk? Our goal is to store user-generated images efficiently and safely sync them via CloudKit, without incurring excessive local database bloat or CloudKit network overhead. Any detailed guidance or internal performance considerations would be greatly appreciated. Thank you, Paul Barry Founder & Lead Developer — Boat Buddy / Vessel Buddy iOS App Archipelago Environmental Solutions Inc.

I'm seeing a lot of these in my logs: PersistentIdentifier PersistentIdentifier(id: SwiftData.PersistentIdentifier.ID(url: x-swiftdata://Course/BC9CF99A-DE6A-46F1-A18D-8034255A56D8), implementation: SwiftData.PersistentIdentifierImplementation) was remapped to a temporary identifier during save: PersistentIdentifier(id: SwiftData.PersistentIdentifier.ID(url: x-coredata:///Course/t58C849CD-D895-4773-BF53-3F63CF48935B210), implementation: SwiftData.PersistentIdentifierImplementation). This is a fatal logic error in DefaultStore ... though everything seems to work. Does anyone know what this means in this context? Anything I can do to not have this appear?

Since publishing new record types to my CloudKit schema in production, a previously unchanged record type has stopped indexing new records. While records of this type are successfully saved without errors, they are not returned in query results—they can only be accessed directly via their recordName. This issue occurs exclusively in the Production environment, both in the CloudKit Console and our iOS app. The problem began on July 21, 2025, and continues to persist. The issue affects only new records of this specific record type; all other types are indexing and querying as expected. The affected record's fields are properly configured with the appropriate index types (e.g., QUERYABLE) and have been not been modified prior to publishing the schema. With this, are there any steps I should take to restore indexing functionality for this record type in Production? There have been new records inserted, and I would prefer to not have to reset the production database, if possible.

Background I have an established app in the App Store which has been using NSPersistentCloudkitContainer since iOS 13 without any issues. I've been running my app normally on an iOS device running the iOS 15 betas, mainly to see problems arise before my users see them. Ever since iOS 15 (beta 4) my app has failed to sync changes - no matter how small the change. An upload 'starts' but never completes. After a minute or so the app quits to the Home Screen and no useful information can be gleaned from crash reports. Until now I've had no idea what's going on. Possible Bug in the API? I've managed to replicate this behaviour on the simulator and on another device when building my app with Xcode 13 (beta 5) on iOS 15 (beta 5). It appears that NSPersistentCloudkitContainer has a memory leak and keeps ramping up the RAM consumption (and CPU at 100%) until the operating system kills the app. No code of mine is running. I'm not really an expert on these things and I tried to use Instruments to see if that would show me anything. It appears to be related to NSCloudkitMirroringDelegate getting 'stuck' somehow but I have no idea what to do with this information. My Core Data database is not tiny, but not massive by any means and NSPersistentCloudkitContainer has had no problems syncing to iCloud prior to iOS 15 (beta 4). If I restore my App Data (from an external backup file - 700MB with lots of many-many, many-one relationships, ckAssets, etc.) the data all gets added to Core Data without an issue at all. The console log (see below) then shows that a sync is created, scheduled & then started... but no data is uploaded. At this point the memory consumption starts and all I see is 'backgroundTask' warnings appear (only related to CloudKit) with no code of mine running. CoreData: CloudKit: CoreData+CloudKit: -[PFCloudKitExporter analyzeHistoryInStore:withManagedObjectContext:error:](501): <PFCloudKitExporter: 0x600000301450>: Exporting changes since (0): <NSPersistentHistoryToken - { "4B90A437-3D96-4AC9-A27A-E0F633CE5D9D" = 906; }> CoreData: CloudKit: CoreData+CloudKit: -[PFCloudKitExportContext processAnalyzedHistoryInStore:inManagedObjectContext:error:]_block_invoke_3(251): Finished processing analyzed history with 29501 metadata objects to create, 0 deleted rows without metadata. CoreData: CloudKit: CoreData+CloudKit: -[NSCloudKitMirroringDelegate _scheduleAutomatedExportWithLabel:activity:completionHandler:](2800): <NSCloudKitMirroringDelegate: 0x6000015515c0> - Beginning automated export - ExportActivity: <CKSchedulerActivity: 0x60000032c500; containerID=<CKContainerID: 0x600002ed3240; containerIdentifier=iCloud.com.nitramluap.Somnus, containerEnvironment="Sandbox">, identifier=com.apple.coredata.cloudkit.activity.export.4B90A437-3D96-4AC9-A27A-E0F633CE5D9D, priority=2, xpcActivityCriteriaOverrides={ Priority=Utility }> CoreData: CloudKit: CoreData+CloudKit: -[NSCloudKitMirroringDelegate executeMirroringRequest:error:](765): <NSCloudKitMirroringDelegate: 0x6000015515c0>: Asked to execute request: <NSCloudKitMirroringExportRequest: 0x600002ed2a30> CBE1852D-7793-46B6-8314-A681D2038B38 2021-08-13 08:41:01.518422+1000 Somnus[11058:671570] [BackgroundTask] Background Task 68 ("CoreData: CloudKit Export"), was created over 30 seconds ago. In applications running in the background, this creates a risk of termination. Remember to call UIApplication.endBackgroundTask(_:) for your task in a timely manner to avoid this. 2021-08-13 08:41:03.519455+1000 Somnus[11058:671570] [BackgroundTask] Background Task 154 ("CoreData: CloudKit Scheduling"), was created over 30 seconds ago. In applications running in the background, this creates a risk of termination. Remember to call UIApplication.endBackgroundTask(_:) for your task in a timely manner to avoid this. Just wondering if anyone else is having a similar issue? It never had a problem syncing an initial database restore prior to iOS 15 (beta 4) and the problems started right after installing iOS 15 (beta 4). I've submitted this to Apple Feedback and am awaiting a response (FB9412346). If this is unfixable I'm in real trouble (and my users are going to be livid). Thanks in advance!

I'm testing my app before releasing to testers, and my app (both macOS and iOS) is crashing when I perform one operation, but only in the production build. I have data that loads from a remote source, and can be periodically updated. There is an option to delete all of that data from the iCloud data store, unless the user has modified a record. Each table has a flag to indicate that (userEdited). Here's the function that is crashing: func deleteCommonData<T:PersistentModel & SDBuddyModel>(_ type: T.Type) throws { try modelContext.delete(model: T.self, where: #Predicate<T> { !$0.userEdited }) } Here's one of the calls that results in a crash: try modelManager.deleteCommonData(Link.self) Here's the error from iOS Console: SwiftData/DataUtilities.swift:85: Fatal error: Couldn't find \Link.<computed 0x0000000104b9d208 (Bool)> on Link with fields [SwiftData.Schema.PropertyMetadata(name: "id", keypath: \Link.<computed 0x0000000104b09b44 (String)>, defaultValue: Optional("54EC6602-CA7C-4EC7-AC06-16E7F2E22DE7"), metadata: nil), SwiftData.Schema.PropertyMetadata(name: "name", keypath: \Link.<computed 0x0000000104b09b84 (String)>, defaultValue: Optional(""), metadata: nil), SwiftData.Schema.PropertyMetadata(name: "url", keypath: \Link.<computed 0x0000000104b09bc4 (String)>, defaultValue: Optional(""), metadata: nil), SwiftData.Schema.PropertyMetadata(name: "desc", keypath: \Link.<computed 0x0000000104b09c04 (String)>, defaultValue: Optional(""), metadata: nil), SwiftData.Schema.PropertyMetadata(name: "userEdited", keypath: \Link.<computed 0x0000000104b09664 (Bool)>, defaultValue: Optional(false), metadata: nil), SwiftData.Schema.PropertyMetadata(name: "modified", keypath: \Link.<computed 0x0000000104b09c44 (Date)>, defaultVal<…> Here's a fragment of the crash log: Exception Type: EXC_BREAKPOINT (SIGTRAP) Exception Codes: 0x0000000000000001, 0x000000019373222c Termination Reason: Namespace SIGNAL, Code 5, Trace/BPT trap: 5 Terminating Process: exc handler [80543] Thread 0 Crashed: 0 libswiftCore.dylib 0x19373222c _assertionFailure(_:_:file:line:flags:) + 176 1 SwiftData 0x22a222160 0x22a1ad000 + 479584 2 SwiftData 0x22a2709c0 0x22a1ad000 + 801216 3 SwiftData 0x22a221b08 0x22a1ad000 + 477960 4 SwiftData 0x22a27b0ec 0x22a1ad000 + 844012 5 SwiftData 0x22a27b084 0x22a1ad000 + 843908 6 SwiftData 0x22a28182c 0x22a1ad000 + 870444 7 SwiftData 0x22a2809e8 0x22a1ad000 + 866792 8 SwiftData 0x22a285204 0x22a1ad000 + 885252 9 SwiftData 0x22a281c7c 0x22a1ad000 + 871548 10 SwiftData 0x22a27cf6c 0x22a1ad000 + 851820 11 SwiftData 0x22a27cc48 0x22a1ad000 + 851016 12 SwiftData 0x22a27a6b0 0x22a1ad000 + 841392 13 SwiftData 0x22a285b2c 0x22a1ad000 + 887596 14 SwiftData 0x22a285a10 0x22a1ad000 + 887312 15 SwiftData 0x22a285bcc 0x22a1ad000 + 887756 16 SwiftData 0x22a27cf6c 0x22a1ad000 + 851820 17 SwiftData 0x22a27cc48 0x22a1ad000 + 851016 18 SwiftData 0x22a27a6b0 0x22a1ad000 + 841392 19 SwiftData 0x22a27c0d8 0x22a1ad000 + 848088 20 SwiftData 0x22a27a654 0x22a1ad000 + 841300 21 SwiftData 0x22a1be548 0x22a1ad000 + 70984 22 SwiftData 0x22a1cfd64 0x22a1ad000 + 142692 23 SwiftData 0x22a1b9618 0x22a1ad000 + 50712 24 SwiftData 0x22a1d2e8c 0x22a1ad000 + 155276 25 CoreData 0x187fbb568 thunk for @callee_guaranteed () -> (@out A, @error @owned Error) + 28 26 CoreData 0x187fc2300 partial apply for thunk for @callee_guaranteed () -> (@out A, @error @owned Error) + 24 27 CoreData 0x187fc19c4 closure #1 in closure #1 in NSManagedObjectContext._rethrowsHelper_performAndWait<A>(fn:execute:rescue:) + 192 28 CoreData 0x187fbbda8 thunk for @callee_guaranteed @Sendable () -> () + 28 29 CoreData 0x187fbbdd0 thunk for @escaping @callee_guaranteed @Sendable () -> () + 28 30 CoreData 0x187f663fc developerSubmittedBlockToNSManagedObjectContextPerform + 252 31 libdispatch.dylib 0x180336ac4 _dispatch_client_callout + 16 32 libdispatch.dylib 0x18032c940 _dispatch_lane_barrier_sync_invoke_and_complete + 56 33 CoreData 0x187fd7290 -[NSManagedObjectContext performBlockAndWait:] + 364 34 CoreData 0x187fc1fb8 NSManagedObjectContext.performAndWait<A>(_:) + 544 35 SwiftData 0x22a1b877c 0x22a1ad000 + 46972 36 SwiftData 0x22a1be2a8 0x22a1ad000 + 70312 37 SwiftData 0x22a1c0e34 0x22a1ad000 + 81460 38 SwiftData 0x22a23ea94 0x22a1ad000 + 596628 39 SwiftData 0x22a256828 0x22a1ad000 + 694312 40 Sourdough Buddy 0x104e5dc98 specialized ModelManager.deleteCommonData<A>(_:) + 144 (ModelManager.swift:128) [inlined] 41 Sourdough Buddy 0x104e5dc98 closure #1 in SettingsView.clearStarterData.getter + 876 (SettingsView.swift:243) It works if I do the following instead: try modelContext.delete(model: Link.self, where: #Predicate { !$0.userEdited }) Why would the func call work in development, but crash in production? And why does doing the more verbose way work instead? I think this is a bug. Thanks

I'm running a project with these settings: Default Actor Isolation: MainActor Approachable Concurrency: Yes Strict Concurrency Checking: Complete (this issue does not appear on the other two modes) I receive a warning for this very simple use case. Can I actually fix anything about this or is this a case of Core Data not being entirely ready for this? In reference to this, there was a workaround listed in the release notes of iOS 26 beta 5 (https://forums.swift.org/t/defaultisolation-mainactor-and-core-data-background-tasks/80569/22). Does this still apply as the only fix for this? This is a simplified sample meant to run on a background context. The issue obviously goes away if this function would just run on the MainActor, then I can remove the perform block entirely. class DataHandler { func createItem() async { let context = ... await context.perform { let newGame = Item(context: context) /// Main actor-isolated property 'timestamp' can not be mutated from a Sendable closure newGame.timestamp = Date.now // ... } } } The complete use case would be more like this: nonisolated struct DataHandler { @concurrent func saveItem() async throws { let context = await PersistenceController.shared.container.newBackgroundContext() try await context.perform { let newGame = Item(context: context) newGame.timestamp = Date.now try context.save() } } }

Hi everyone, I'm looking for the correct architectural guidance for my SwiftData implementation. In my Swift project, I have dedicated async functions for adding, editing, and deleting each of my four models. I created these functions specifically to run certain logic whenever these operations occur. Since these functions are asynchronous, I call them from the UI (e.g., from a button press) by wrapping them in a Task. I've gone through three different approaches and am now stuck. Approach 1: @MainActor Functions Initially, my functions were marked with @MainActor and worked on the main ModelContext. This worked perfectly until I added support for App Intents and Widgets, which caused the app to crash with data race errors. Approach 2: Passing ModelContext as a Parameter To solve the crashes, I decided to have each function receive a ModelContext as a parameter. My SwiftUI views passed the main context (which they get from @Environment(\.modelContext)), while the App Intents and Widgets created and passed in their own private context. However, this approach still caused the app to crash sometimes due to data race errors, especially during actions triggered from the main UI. Approach 3: Creating a New Context in Each Function I moved to a third approach where each function creates its own ModelContext to work on. This has successfully stopped all crashes. However, now the UI actions don't always react or update. For example, when an object is added, deleted, or edited, the change isn't reflected in the UI. I suspect this is because the main context (driving the UI) hasn't been updated yet, or because the async function hasn't finished its work. My Question I'm not sure what to do or what the correct logic should be. How should I structure my data operations to support the main UI, Widgets, and App Intents without causing crashes or UI update failures? Here is the relevant code using my third (and current) approach. I've shortened the helper functions for brevity. // MARK: - SwiftData Operations extension DatabaseManager { /// Creates a new assignment and saves it to the database. public func createAssignment( name: String, deadline: Date, notes: AttributedString, forCourseID courseID: UUID, /*...other params...*/ ) async throws -> AssignmentModel { do { let context = ModelContext(container) guard let course = findCourse(byID: courseID, in: context) else { throw DatabaseManagerError.itemNotFound } let newAssignment = AssignmentModel( name: name, deadline: deadline, notes: notes, course: course, /*...other properties...*/ ) context.insert(newAssignment) try context.save() // Schedule notifications and add to calendar _ = try? await scheduleReminder(for: newAssignment) newAssignment.calendarEventIDs = await CalendarManager.shared.addEventToCalendar(for: newAssignment) try context.save() await MainActor.run { WidgetCenter.shared.reloadTimelines(ofKind: "AppWidget") } return newAssignment } catch { throw DatabaseManagerError.saveFailed } } /// Finds a specific course by its ID in a given context. public func findCourse(byID id: UUID, in context: ModelContext) -> CourseModel? { let predicate = #Predicate<CourseModel> { $0.id == id } let fetchDescriptor = FetchDescriptor<CourseModel>(predicate: predicate) return try? context.fetch(fetchDescriptor).first } } // MARK: - Helper Functions (Implementations omitted for brevity) /// Schedules a local user notification for an event. func scheduleReminder(for assignment: AssignmentModel) async throws -> String { // ... Full implementation to create and schedule a UNNotificationRequest return UUID().uuidString } /// Creates a new event in the user's selected calendars. extension CalendarManager { func addEventToCalendar(for assignment: AssignmentModel) async -> [String] { // ... Full implementation to create and save an EKEvent return [UUID().uuidString] } } Thank you for your help.

I am using SwiftData with CloudKit to synchronize data across multiple devices, and I have encountered an issue: occasionally, abnormal sync behavior occurs between two devices (it does not happen 100% of the time—only some users have reported this problem). It seems as if synchronization between the two devices completely stops; no matter what operations are performed on one end, the other end shows no response. After investigating, I suspect the issue might be caused by both devices simultaneously modifying the same field, which could lead to CloudKit's logic being unable to handle such conflicts and causing the sync to stall. Are there any methods to avoid or resolve this situation? Of course, I’m not entirely sure if this is the root cause. Has anyone encountered a similar issue?

Problem The following code doesn't work: let predicate = #Predicate<Car> { car in car.size == size //This doesn't work } Console Error Query encountered an error: SwiftData.SwiftDataError(_error: SwiftData.SwiftDataError._Error.unsupportedPredicate) Root cause Size is an enum, #Predicate works with other type such as String however doesn't work with enum Enum value is saved however is not filtered by #Predicate Environment Xcode: 15.0 (15A240d) - App Store macOS: 14.0 (23A339) - Release Candidate Steps to reproduce Run the app on iOS 17 or macOS Sonoma Press the Add button Notice that the list remains empty Expected behaviour List should show the newly created small car Actual behaviour List remains empty inspite of successfully creating the small car. Feedback FB13194334 Code Size enum Size: String, Codable { case small case medium case large } Car import SwiftData @Model class Car { let id: UUID let name: String let size: Size init( id: UUID, name: String, size: Size ) { self.id = id self.name = name self.size = size } } ContentView struct ContentView: View { var body: some View { NavigationStack { CarList(size: .small) } } CarList import SwiftUI import SwiftData struct CarList: View { let size: Size @Environment(\.modelContext) private var modelContext @Query private var cars: [Car] init(size: Size) { self.size = size let predicate = #Predicate<Car> { car in car.size == size //This doesn't work } _cars = Query(filter: predicate, sort: \.name) } var body: some View { List(cars) { car in VStack(alignment: .leading) { Text(car.name) Text("\(car.size.rawValue)") Text(car.id.uuidString) .font(.footnote) } } .toolbar { Button("Add") { createCar() } } } private func createCar() { let name = "aaa" let car = Car( id: UUID(), name: name, size: size ) modelContext.insert(car) } }

Hello, I'm planning to had an onboarding to one of my apps. I am thinking about a way for a user to not see the onboarding again if he installs the app on another device. So for example, the user completes the onboarding on its iPhone, then downloads the app on its iPad and launch it, he doesn't see the onboarding a second time. I thought about using iCloud NSUbiquitousKeyValueStored to store the onboarding completion state. But I'm not sure when the data is synced to the other device logged into the same Apple account: Immediately even if the app is not installed on the other device (independent from the app, only iCloud thing)? At the same time as the app install on the other device? After the app is first launched on the other device? Of course synchronisation will depend on the Internet connection, speed, etc. so the app should handle the case where the data is not here but what would be the best case scenario? Thank you, Axel

LSUB always returns all the subscribed folders. For example lsub "" "test/*" returns a list of all the folders and not just subscribed folders that are subfolders of test. I.e, it returns the same folder list as lsub "" "*". For more details please see https://bugzilla.mozilla.org/show_bug.cgi?id=1817707#c15

In the future, is there any plans to have AppMigrationKit for macOS-Windows cross transfers (or Linux, ChromeOS, HarmonyOS NEXT, etc)? Additionally, will the migration framework remain just iOS <-> Android or will it extend to Windows tablets, ChromeOS Tablets, HarmonyOS NEXT, KaiOS, Series 30+, Linux mobile, etc.

I have a ModelActor that creates a hierarchy of models and returns a PersistentIdentifier for the root. I'd like to do that in a transaction, but I don't know of a good method of getting that identifier if the models are created in a transaction. For instance, an overly simple example: func createItem(timestamp: Date) throws -> PersistentIdentifier { try modelContext.transaction { let item = Item(timestamp: timestamp) modelContext.insert(item) } // how to return item.persistentModelID? } I can't return the item.persistentModelID from the transaction closure and even if I could, it will be a temporary ID until after the transaction is executed. I can't create the Item outside the transaction and just have the transaction do an insert because swift will raise a data race error if you then try to return item.persistentModelID. Is there any way to do this besides a modelContext.fetch* with separate unique identifiers?

I've been seeing something that I find odd when using two SwiftData models where if I have one model (book, in this case) that has an optional array of another model (page, in this case), the optional array starts out as set to nil, but after about 20 seconds it updates to being an empty array. I see it in Previews and after building. Is this expected behavior? Should I just assume that if there is an optional array in my model it will eventually be initialized to an empty array? Code is below. import SwiftUI import SwiftData @Model final class Book { var title: String = "New Book" @Relationship var pages: [Page]? = nil init(title: String) { self.title = title } } @Model final class Page { var content: String = "Page Content" var book: Book? = nil init() { } } struct ContentView: View { @Environment(\.modelContext) private var modelContext @Query private var books: [Book] var body: some View { NavigationSplitView { List { ForEach(books) { book in NavigationLink { Text("\(book.title)") Text(book.pages?.debugDescription ?? "pages is nil") } label: { Text("\(book.title)") Spacer() Text("\(book.pages?.count.description ?? "pages is nil" )") } } } HStack { Button("Clear Data") { clearData() } Button("Add Book") { addBook() } } .navigationSplitViewColumnWidth(min: 180, ideal: 200) } detail: { Text("Select an item") } } private func clearData() { for book in books { modelContext.delete(book) } try? modelContext.save() } private func addBook() { let newBook = Book(title: "A New Book") modelContext.insert(newBook) } } @main struct BookPageApp: App { var sharedModelContainer: ModelContainer = { let schema = Schema([Book.self, Page.self]) let modelConfiguration = ModelConfiguration(schema: schema, isStoredInMemoryOnly: false) do { return try ModelContainer(for: schema, configurations: [modelConfiguration]) } catch { fatalError("Could not create ModelContainer: \(error)") } }() var body: some Scene { WindowGroup { ContentView() } .modelContainer(sharedModelContainer) } } #Preview { ContentView() .modelContainer(for: Book.self, inMemory: true) }

I'm setting up App Entities for my SwiftData models and I'm not sure about the best way to reference SwiftData model properties in the AppEntity. I have a SwiftData model with many properties: @Model final class Contact { @Attribute(.unique) var id: UUID = UUID() var name: String var phoneNumber: String var email: String var website: URL? var birthday: Date? var notes: String // ... many more properties } I want to expose these properties on my AppEntity so they're available for system features, such as giving Apple Intelligence more context about on-screen content. struct ContactEntity: AppEntity { var id: UUID @Property(title: "Name") var name: String @Property(title: "Phone") var phoneNumber: String @Property(title: "Email") var email: String // ... all the other properties } I couldn't find guidance in the documentation for this specific situation. I've considered two approaches: Add @Property variables to the AppEntity for each SwiftData model property and copy all values from the SwiftData model to the AppEntity in the AppEntity initializer — but I recall this being discouraged in previous WWDC sessions since it duplicates data and can become stale Use @ComputedProperty to fetch the model and access the single properties — this seems like an alternative, but fetching the entire model just to access individual properties doesn't feel right What is the recommended approach when SwiftData is the data source? Thank you!