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?

What is the idiomatic way to use a ModelContext in a document based SwiftData app from a background thread? The relevant DocumentGroup initializers do not give us direct access to a ModelContainer, only to a ModelContext. Is it safe to take its modelContext.container and pass it around (for creating a ModelContext on it on a background thread) or to construct a ModelActor with it? Is it safe to e.g. put a ModelActor so created into the environment of the root view of the window and execute various async data operations on it in Tasks throughout the app, as long as these are dispatched from within the window whose root view's ModelContext was used for getting the ModelContainer?

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.

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!

Good morning everyone! Today I have a question about using SwiftData with CloudKit and Widgets. I recently set up my project for SwiftData and CloudKit synchronization, but for some reason, I’m not able to give my Widget access to this data. CloudKit works perfectly fine for my main app, but the Widget only shows placeholder data(the placeholder data which were defined in the get functions as catch, this is sure). I have set the CloudKit capability for my Widget extension and tried fetching data with the get-functions in the code below. I also ensured that the data model files are members of the Widget extension target and that the Widget extension uses the same CloudKit container as the main app. I wondered if it is possible and reasonable to save a copy of my CloudKit data in an App Group container, but in that case, the information shown in the Widget are not always up-to-date, so a solution that fetches data directly from CloudKit would be better. Has anyone had experience with this case? I couldn’t find much information about this problem online. In the code below, many parts have been deleted or altered because they are not relevant to the problem, as they don’t fetch data. The variables, functions, and data models in the code may sometimes have German names, but I hope you can still understand it. Thanks for your help! struct Provider: AppIntentTimelineProvider { //[Placeholder and snapshot] func timeline(for configuration: ConfigurationAppIntent, in context: Context) async -> Timeline<CleverEntry> { let entry = await loadAllVariables() return Timeline(entries: [entry], policy: .after(Date().addingTimeInterval(60 * 5))) } @MainActor private func getExam() -> [PruefungM] { //Old, local version /* guard let modelContainer = try? ModelContainer(for: PruefungM.self) else { return [] } let descriptor = FetchDescriptor<PruefungM>() let PRF = try? modelContainer.mainContext.fetch(descriptor) return PRF ?? [] */ do { let configuration = ModelConfiguration(cloudKitDatabase: .private("iCloud.my_bundle_id")) let container = try ModelContainer( for: PruefungM.self, configurations: configuration ) let descriptor = FetchDescriptor<PruefungM>() return try container.mainContext.fetch(descriptor) } catch { print("❌ Error(CloudKit): \(error)") return [] } } @MainActor private func getHAF() -> [HausaufgabeM] { do { let configuration = ModelConfiguration(cloudKitDatabase: .private("iCloud.my_bundle_id")) let container = try ModelContainer( for: HausaufgabeM.self, configurations: configuration ) let descriptor = FetchDescriptor<HausaufgabeM>() return try container.mainContext.fetch(descriptor) } catch { print("❌ Error (CloudKit): \(error)") return [] } } @MainActor private func loadAllVariables() -> CleverEntry { print("Function started") let HAF = getHAF() let PRF = getExam() //handling and returning the data } }

I'm developing an app that uses CloudKit synchronization with SwiftData and on visionOS I added an App Settings bundle. I have noticed that sometimes, when the app is open and the user changes a setting from the App Settings bundle, the following fatal error occurs: SwiftData/BackingData.swift:831: Fatal error: This model instance was destroyed by calling ModelContext.reset and is no longer usable. The setting is read within the App struct in the visionOS app target using @AppStorage and this value is in turn used to set the passthrough video dimming via the .preferredSurroundingsEffect modifier. The setting allows the user to specify the dimming level as dark, semi dark, or ultra dark. The fatal error appears to occur intermittently although the first time it was observed was after adding the settings bundle. As such, I suspect there is some connection between those code changes and this fatal error even though they do not directly relate to SwiftData.

Background: Our non-production App was using SwiftData locally. Yesterday we followed the documentation to enable CloudKit: https://developer.apple.com/documentation/cloudkit/enabling-cloudkit-in-your-app iCloud Works: Data is properly syncing via iCloud between 2 devices. Add on one shows on the other; delete on one deletes on the other. Today we logged into CloudKit Console for the first time; but there are no databases showing. We verified: Users and Roles: we have “Access to Cloud Managed… Certificates” Certificates, Identifiers & Profiles: our app has iCloud capabilities and is using our iCloud Container Signed into CloudKit Console with same developer ID as AppStoreConnect This is also the Apple ID of the iCloud account that has synced data from our app. In Xcode > Signing & Capabilities we are signed in as our Company team. Any guidance or tips to understanding how to what’s going on in CloudKit Console and gaining access to the database is appreciated!

Definitely one of the stranger quirks of SwiftData I've come across. I have a ScriptView that shows Line entities related to a Production, and a TextEnterScriptView that’s presented in a sheet to input text. I’m noticing that every time I type in the TextEditor within TextEnterScriptView, a new Line shows up in ScriptView — even though I haven’t explicitly inserted it into the modelContext. I'm quite confused because even though I’m only assigning a new Line to a local @State array in TextEnterScriptView, every keystroke in the TextEditor causes a duplicate Line to appear in ScriptView. In other words, Why is SwiftData creating new Line entities every time I type in the TextEditor, even though I’m only assigning to a local @State array and not explicitly inserting them into the modelContext? Here is my minimal reproducible example: import SwiftData import SwiftUI @main struct testApp: App { var body: some Scene { WindowGroup { ContentView() .modelContainer(for: Line.self, isAutosaveEnabled: false) } } } struct ContentView: View { @Environment(\.modelContext) var modelContext @Query(sort: \Production.title) var productions: [Production] var body: some View { NavigationStack { List(productions) { production in NavigationLink(value: production) { Text(production.title) } } .navigationDestination(for: Production.self) { production in ScriptView(production: production) } .toolbar { Button("Add", systemImage: "plus") { let production = Production(title: "Test \(productions.count + 1)") modelContext.insert(production) do { try modelContext.save() } catch { print(error) } } } .navigationTitle("Productions") } } } struct ScriptView: View { @Query private var lines: [Line] let production: Production @State private var isShowingSheet: Bool = false var body: some View { List { ForEach(lines) { line in Text(line.content) } } .toolbar { Button("Show Sheet") { isShowingSheet.toggle() } } .sheet(isPresented: $isShowingSheet) { TextEnterScriptView(production: production) } } } struct TextEnterScriptView: View { @Environment(\.dismiss) var dismiss @State private var text = "" @State private var lines: [Line] = [] let production: Production var body: some View { NavigationStack { TextEditor(text: $text) .onChange(of: text, initial: false) { lines = [Line(content: "test line", production: production)] } .toolbar { Button("Done") { dismiss() } } } } } @Model class Production { @Attribute(.unique) var title: String @Relationship(deleteRule: .cascade, inverse: \Line.production) var lines: [Line] = [] init(title: String) { self.title = title } } @Model class Line { var content: String var production: Production? init(content: String, production: Production?) { self.content = content self.production = production } }

Hello, I recently switched my app from flutter which was using sqlite3 database. I would like to migrate my existing users to SwiftData. The issue is I do not know where to start in finding the database for the current users, reading the data and inserting into the SwiftData schema. I tried searching but not clear on how to proceed. Any help pointing in the right direction would be great. Thanks.

Does anyone have this error and my app can't be searched in the Apple Store

I'm sorta baffled right now. I am trying to wonder how I might detect a updated SQL Store in an older app. have a baseline app, and create a SQL-based repository in an updated app, change the model and verify that you can see the updated model version. Using lightweight migration re-run the older app (which will inherit the newer SQL repository). YIKES - no error when creating the NSPersistenStoreCoordinator! Nothing in the metadata to imply the store is newer than the model: [_persistentStoreCoordinator metadataForPersistentStore:store] My question: is there any way to detect this condition? David

After a recent iOS update, my app is not synching between devices. I'm not seeing or getting any errors. CLoudKit Logs show activity, but it's not happening realtime. Even if I close and reopen the app, it won't sync between devices. It almost looks like it only has local storage now and CloudKit is not working on it anymore. STEPS TO REPRODUCE Use app on two devices with the same Apple ID. Create a user and one device and it won't show up on the other device. Vice Versa.

Hello, our application works with Core Data to save some datas about its activity. We have background Tasks implemented and our app execution in background shows this error message in the Logs: error: Failed to acquire background task assertion for task 'CoreData: Executing write request'. Anyone could explain what this message means? Could it be that NSManagedObjectContext changes might not be written?

When the following models in SwiftData, @Model final class UndoRedoData { var id: [Int] init(id: [Int]) { self.id = id } } I created the following code. struct ContentView: View { @ObservedObject var swiftDataViewModel = SwiftDataArrayViewModel.shared @State private var idArray: [Int] = [1,2,3,4] @State private var firstviewSwich: Bool = true @State private var twoviewSwich: Bool = false @State private var threeviewSwich: Bool = false var body: some View { VStack { if firstviewSwich == true { Button(action: addItem) { Text("1.New Item") } } if twoviewSwich == true { Button { forArrayData() } label: { Text("2.Data Road") } } if threeviewSwich == true { Button(action: undoItem) { Text("3.Undo") } } } } private func addItem() { withAnimation { let newItem = UndoRedoData(id: [1,2,3,4]) swiftDataViewModel.taskContext.insert(newItem) do { try swiftDataViewModel.taskContext.save() } catch { print(error) } swiftDataViewModel.fetchItems() firstviewSwich.toggle() twoviewSwich.toggle() } } private func forArrayData() { twoviewSwich.toggle() for data in idArray { swiftDataViewModel.idUndoCreate(id: data, undoManager: swiftDataViewModel.arrayItemUndoManager) } threeviewSwich.toggle() } private func undoItem() { swiftDataViewModel.arrayItemUndoManager.undo() threeviewSwich.toggle() firstviewSwich.toggle() } } class SwiftDataArrayViewModel: ObservableObject { static let shared = SwiftDataArrayViewModel() let modelContainer: ModelContainer @ObservationIgnored lazy var taskContext: ModelContext = { return ModelContext(modelContainer) }() @Published var arrayItems = [UndoRedoData]() @Published var arrayItemUndoManager = UndoManager() init() { let schema = Schema([UndoRedoData.self]) let modelConfiguration = ModelConfiguration(schema: schema, isStoredInMemoryOnly: false) do { modelContainer = try ModelContainer(for: schema, configurations: [modelConfiguration]) } catch { fatalError(error) } fetchItems() } func fetchItems() { let fetchDescriptor = FetchDescriptor<UndoRedoData>() do { arrayItems = try taskContext.fetch(fetchDescriptor) } catch { fatalError(error) } } func idUndoCreate(id: Int, undoManager: UndoManager?) { undoManager?.registerUndo(withTarget: self) { target in target.removeID() } } func removeID() { if let firstUndoRedoData = arrayItems.first { print("Before Delete:\(firstUndoRedoData.id)") if !firstUndoRedoData.id.isEmpty { firstUndoRedoData.id.removeLast() } print("After Delete:\(firstUndoRedoData.id)") } do { try taskContext.save() } catch { print(error) } fetchItems() } } In this code, 1. Create an Item in New Item, 2. Execute Data Road and register the data in the array that is the same value as the data created in New Item in SwiftData one by one in UndoManager by for data in idArray. This is done because the data in the array and the data created by New Item in SwiftData can be known in advance. private func forArrayData() { twoviewSwich.toggle() for data in idArray { swiftDataViewModel.idUndoCreate(id: data, undoManager: swiftDataViewModel.arrayItemUndoManager) } // class SwiftDataArrayViewModel: ObservableObject func idUndoCreate(id: Int, undoManager: UndoManager?) { undoManager?.registerUndo(withTarget: self) { target in target.removeID() } } After registering in UndoManager, when Undo is executed with 3. Undo, instead of being able to perform Undo where one id is deleted each time, all the data of the id in SwiftData is deleted in a one-time Undo. I would like to be able to delete one id each time Undo is performed and restore them in sequence, but I can only delete them all once. Does this mean that such registration to UndoManager should not be done with for statements, etc.? Or is there another problem in the code? I want to make sure that one id is deleted for each Undo executed.

I'm trying to set up server-to-server authentication with CloudKit Web Services, but keep getting AUTHENTICATION_FAILED errors. I've tried multiple environment settings and debugging approaches without success. What I've Tried I created a Swift script to test the connection. Here's the key part that handles the authentication: // Get current ISO 8601 date let iso8601Formatter = ISO8601DateFormatter() iso8601Formatter.formatOptions = [.withInternetDateTime] let dateString = iso8601Formatter.string(from: Date()) // Create SHA-256 hash of request body let bodyHash = SHA256.hash(data: bodyData).compactMap { String(format: "%02x", $0) }.joined() // Get path from URL let path = request.url?.path ?? "/" // String to sign let method = request.httpMethod ?? "POST" let stringToSign = "\(method):\(path):\(dateString):\(bodyHash)" // Sign the string with EC private key let signature = try createSignature(stringToSign: stringToSign) // Add headers request.setValue(dateString, forHTTPHeaderField: "X-Apple-CloudKit-Request-ISO8601Date") request.setValue(KEY_ID, forHTTPHeaderField: "X-Apple-CloudKit-Request-KeyID") request.setValue(signature, forHTTPHeaderField: "X-Apple-CloudKit-Request-SignatureV1") } I've made a request to this endpoint: What's Happening I get a 401 status with this response: "uuid" : "173179e2-c5a5-4393-ab4f-3cec194edd1c", "serverErrorCode" : "AUTHENTICATION_FAILED", "reason" : "Authentication failed" } What I've Verified The key validates correctly and generates signatures The date/time is synchronized with the server The key ID matches what's in CloudKit Dashboard I've tried all three environments: development, Development (capital D), and production The container ID is formatted correctly Debug Information My debugging reveals: The EC key is properly formatted (SEC1 format) Signature generation works No time synchronization issues between client and server All environment tests return the same 401 error Questions Has anyone encountered similar issues with CloudKit server-to-server authentication? Are there specific container permissions needed for server-to-server keys? Could there be an issue with how the private key is formatted or processed? Are there any known issues with the CloudKit Web Services API that might cause this? Any help would be greatly appreciated!

Problem Description: When a device (Device 2) stays offline for an extended period after a record is deleted from another synced device (Device 1) via CloudKit, is it possible for Device 2 to miss the deletion notification when it reconnects, even when using CKSyncEngine? This scenario raises questions about whether CKSyncEngine can reliably sync changes if CloudKit archives or purges metadata related to deletions during the offline period. Steps to Reproduce: At time t0: · Device 1 and Device 2 sync successfully via CKSyncEngine (shared record RecordA). Device 2 goes offline. On Device 1: · Delete RecordA; sync completes via CKSyncEngine. Wait for a duration potentially exceeding CloudKit’s change retention window (if such a window exists). Bring Device 2 back online. Observe synchronization: · Expected Behavior: CKSyncEngine removes RecordA from Device 2. · Observed Behavior: RecordA remains on Device 2. Key Questions: Under these conditions, can Device 2 permanently miss the deletion event due to CloudKit’s internal metadata management? Is there a documented retention policy for CloudKit’s change history, and how does CKSyncEngine handle scenarios where this history is truncated? What is the recommended pattern to ensure no events are missed, regardless of offline duration? Clarifications Needed: · If CloudKit does discard deletion metadata after a period, is this considered a framework limitation, or should developers implement additional safeguards? · Does CKSyncEngine log warnings or errors when it detects incomplete sync histories? Environment: · CKSyncEngine with SQLite · CloudKit Private Database · iOS/macOS latest versions Thank you for clarifying how CKSyncEngine is designed to handle this edge case!

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

I have an app that I signed and distribute between some internal testflight users. Potentially I want to invite some 'Public' beta testers which don't need to validate (_World have read rights in the public database) Question: Do I need to have a working public CloudKit , when users are invited through TestFlight, or are they going to test on the development container? I understand that when I invite beta-tester without authorization (external testers) they cannot access the developer container, so therefore I need to have the production CloudKit container up and running. I have tried to populate the public production container, but for whatever reason my upload app still goes to the development container. I have archived the app, and tried, but no luck. I let xcode manage my certificates/profiles. but what do I need to change to be able to use my upload file to upload the production container, instead of the development. I tried: init() { container = CKContainer(identifier: "iCloud.com.xxxx.xxxx") publicDB = container.publicCloudDatabase I got no error in the console, but data is always populated to the development database, instead the production. I tried to create a provisioning profile, but for some reason Xcode doesn't like it. Tried to create one a different provisioning profile manual through the developer portal, for the app. but xcode doesn't want to use that, and mentions that the requirement are already in place. What can I check/do to solve this.

"No records found" If I create a new record on the console, I can copy the record name. I can then query for recordName and get that individual record back. BUT no other queries work. I cannot query all records. I cannot query by individual property. Just returns "no records found" Seems like my indexes got messed up. Is there a way to reset indexes on prod? This is on a coredata.cloudkit managed zone.

I have an app which uses ubiquitous containers and files in them to share data between devices. It's a bit unusual in that it indexes files in directories the user grants access to, which may or may not exist on a second device - those files are identified by SHA-1 hash. So a second device scanning before iCloud data has fully sync'd can create duplicate references which lead to an unpleasant user experience. To solve this, I store a small binary index in the root of the ubiquitous file container of the shared data, containing all of the known hashes, and as the user proceeds through the onboarding process, a background thread is attempting to "prime" the ubiquitous container by calling FileManager.default.startDownloadingUbiquitousItemAt() for each expected folder and file in a sane order. This likely creates a situation not anticipated by the iOS/iCloud integration's design, as it means my app has a sort of precognition of files it should not yet know about. In the common case, it works, but there is a corner case where iCloud sync has just begun, and very, very little metadata is available (the common case, however, in an emulator), in which two issues come up: I/O may hang indefinitely, trying to read a file as it is arriving. This one I can work around by running the I/O in a thread created with the POSIX pthread_create and using pthread_cancel to kill it after a timeout. Attempts to call FileManager.default.startDownloadingUbiquitousItemAt() fails with an error Error Domain=NSCocoaErrorDomain Code=257 "The file couldn’t be opened because you don’t have permission to view it.". The permissions aspect of it is nonsense, but I can believe there's no applicable "sort of exists, sort of doesn't" error code to use and someone punted. The problem is that this same error will be thrown on any attempt to access that file for the life of the application - a restart is required to make it usable. Clearly, the error or the hallucinated permission failure is cached somewhere in the bowels of iOS's FileManager. I was hoping startAccessingSecurityScopedResource() would allow me to bypass such a cache, as it does with URL.resourceValues() returning stale file sizes and last modified times. But it does not. Is there some way to clear this state without popping up a UI with an Exit button (not exactly the desired iOS user experience)?