Setup I am running a versionedSchema for my SwiftData model and attempting a migration. The new version contains a new attribute, with a type of a new custom enum defined in the @Model class, a default value, and a private(set). Migration was completed with a migrationPlan with nil values for willMigrate and didMigrate. Example - Previous Version @Model class MyNumber { var num: Int init() { // Init Code } } Example - Newest Version @Model class MyNumber { var num: Int private(set) var rounding: RoundAmount = MyNumber.RoundAmount.thirtyMinute init() { // Init Code } enum RoundAmount { case fiveMinute, tenMinute, thirtyMinute } } Issue Running this code, I get a swiftData error for “SwiftData/ModelCoders.swift:1585: nil value passed for a non-optional keyPath, /MyNumber.rounding” I assume this means a failure of the swiftData lightweight migration? I have reverted the version, removed private(set) and re-tried the migration with no success. Using the versionedSchema with migrationPlans, are lightweight migrations possible? Could this be an issue with the use of a custom enum? Other changes in my actual project migrated successfully so I’m lost on why I’m having this issue.

I have been trying to find out the app limits to my app when released into the app store, I understand that in the public database the app worldwide can use 200g of bandwidth free per month. What happens after that? is it throttled? is there a pricing structure for overages? thanks

Hi everyone, In the simple app below, I have a QueryView that has LazyVStack containing 100k TextField's that edit the item's content. The items are fetched with a @Query. On launch, the app will generate 100k items. Once created, when I press any of the TextField's , a severe hang happens, and every time I type a single character, it will cause another hang over and over again. I looked at it in Instruments and it shows that the main thread is busy during the duration of the hang (2.31 seconds) updating QueryView. From the cause and effect graph, the update is caused by @Observable QueryController <Item>.(Bool). Why does it take too long to recalculate the view, given that it's in a LazyVStack? (In other words, why is the hang duration directly proportional to the number of items?) How to fix the performance of this app? I thought adding LazyVStack was all I need to handle the large dataset, but maybe I need to add a custom pagination with .fetchLimit on top of that? (I understand that ModelActor would be an alternative to @Query because it will make the database operations happen outside of the main thread which will fix this problem, but with that I will lose the automatic fetching of @Query.) Thank you for the help! import SwiftData import SwiftUI @main struct QueryPerformanceApp: App { var body: some Scene { WindowGroup { ContentView() .modelContainer(for: [Item.self], inMemory: true) } } } @Model final class Item { var name: String init(name: String) { self.name = name } } struct ItemDetail: View { @Bindable var item: Item var body: some View { TextField("Name", text: $item.name) } } struct QueryView: View { @Query private var items: [Item] var body: some View { ScrollView { LazyVStack { ForEach(items) { item in VStack { ItemDetail(item: item) } } } } } } struct ContentView: View { let itemCount = 100_000 @Environment(\.modelContext) private var context @State private var isLoading = true var body: some View { Group { if isLoading { VStack(spacing: 16) { ProgressView() Text("Generating \(itemCount) items...") } } else { QueryView() } } .task { for i in 1...itemCount { context.insert(Item(name: "Item \(i)")) } try? context.save() isLoading = false } } }

What is the best way to switch between Core Data Persistent Stores? My use case is that I have a multi-user app that stores thousands of data items unique to each user. To me, having Persistent Stores for each user seems like the best design to keep their data separate and private. (If anyone believes that storing the data for all users in one Persistent Store is a better design, I'd appreciate hearing from them.) Customers might switch users 5 to 10 times a day. Switching users must be fast, say a second or two at most.

I have an iOS app using SwiftData with VersionedSchema. The schema is synchronized with an CloudKit container. I previously introduced some model properties that I have now removed, as they are no longer needed. This results in the current schema version being identical to one of the previous ones (except for its version number). This results in the following exception: 'NSInvalidArgumentException', reason: 'Duplicate version checksums across stages detected.' So it looks like we cannot have a newer schema version with an identical content to an older schema version. The intuitive way would be to re-add the old (identical) schema version to the end of the "schemas" list property in the SchemaMigrationPlan, in order to signal that it is the newest one, and to add a migration stage back to it, thus: public enum MySchemaMigrationPlan: SchemaMigrationPlan { public static var schemas: [any VersionedSchema.Type] { [ SchemaV100.self, SchemaV101.self, SchemaV100.self ] } public static var stages: [MigrationStage] { [ migrateV100toV101, migrateV101toV100 ] } However, I am not sure if this is the right way to go, as previously, as I wanted to write unit tests for schema migration and rollback, I tried defining an inverse for each migration stage, so that I could trigger a migration and a rollback from a unit test, which resulted in an exception saying that it is not supported to downgrade a VersionedSchema. I must admit that I solved the original problem by introducing a dummy model property that I will later remove. What would have been the correct approach?

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.

Hi, I am testing a situation with shared CKRecords where the data in the CKRecord syncs fine, but the creatorUserRecordID.recordName and lastModifiedUserRecordID.recordName shows "defaultOwner" (which maps to the CKCurrentUserDefaultName constant) even though I made sure I edit the CKRecord value from a different iCloud account. In fact, on the CloudKit dashboard, it shows the correct user recordIDs in the metadata for the 'Created' and 'Modified' fields, but not in the CKRecord. I am mostly testing this on the iPhone simulator with the debugger attached. Is that a possible reason for this, or is there some other reason the lastModifiedUserRecordID is showing the value for 'CKCurrentUserDefaultName'? It would be pretty difficult to build in functionality to look up changes by a different userID if this is the case.

I’m seeing persistent issues with iCloud Drive hydration and Finder sync on a new M4 MacBook Pro running Sequoia 15.5 (24F74). The same folders hydrate correctly on other Macs (Intel and M1), but not on the M4. ✅ Tried: – killall bird – Safe Mode boot – Toggling iCloud Drive and System Settings > Apple ID – Isolating network, user profile, and running First Aid 🔍 Findings: – EtreCheck report shows consistent high CPU usage from bird with no resolution. – Console logs suggest bird is waiting on local metadata index. – No VPNs installed. No third-party sync tools active. I’ve sanitized and attached the EtreCheck report as text for reference (or can paste if needed). ❓ Questions: 1. Is this a known issue on M4 systems or Sequoia 15.5? 2. Could file system ownership have been impacted by command-line tools? 3. Is there a safe method to reset bird metadata or iCloud sync state locally? Any guidance from Apple or other developers would be appreciated. Thanks!

Hi everyone, I’m facing an issue with CloudKit sync getting stuck during initial device migration in my SwiftData-based app. The app follows a local-first architecture using SwiftData + CloudKit sync, and works correctly for: ✔ Incremental sync ✔ Bi-directional updates ✔ Small datasets However, when onboarding a new device with large historical data, sync becomes extremely slow or appears stuck. Even after two hours data is not fully synced. ~6900 Transactions 🚨 Problem When installing the app on a new iPhone and enabling iCloud sync: • Initial hydration starts • A small amount of data syncs • Then sync stalls indefinitely Observed behaviour: • iPhone → Mac sync works (new changes sync back) • Mac → iPhone large historical migration gets stuck • Reinstalling app / clearing container does not resolve issue • Sync never completes full migration This gives the impression that: CloudKit is trickling data but not progressing after a certain threshold. The architecture is: • SwiftData local store • Manual CloudKit sync layer • Local-first persistence • Background push/pull sync So I understand: ✔ Conflict resolution is custom ✔ Initial import may not be optimized by default But I expected CloudKit to eventually deliver all records. Instead, the new device remains permanently in a “partial state”. ⸻ 🔍 Observations • No fatal CloudKit errors • No rate-limit errors • No quota issues • iCloud is available • Sync state remains “Ready” • Hydration remains “mostlyReady” Meaning: CloudKit does not report failure — but data transfer halts. ⸻ 🤔 Questions Would appreciate guidance on: Is CloudKit designed to support large initial dataset migration via manual sync layers? Or is this a known limitation vs NSPersistentCloudKitContainer? ⸻ Does CloudKit internally throttle historical record fetches? Could it silently stall without error when record volume is high? ⸻ Is there any recommended strategy for: • Bulk initial migration • Progressive hydration • Forcing forward sync progress ⸻ Should initial migration be handled outside CloudKit (e.g. via file transfer / backup restore) before enabling sync? ⸻ 🎯 Goal I want to support: • Large historical onboarding • Multi-device sync • User-visible progress Without forcing migration to Core Data. ⸻ 🙏 Any advice on: • Best practices • Debugging approach • CloudKit behavior in such scenarios would be greatly appreciated. Thank you!

How do I filter data using @Query with a Set of DateComponents? I successfully saved multiple dates using a MultiDatePicker in AddView.swift. In ListView.swift, I want to retrieve all records for the current or today’s date. There are hundreds of examples using @Query with strings and dates, but I haven’t found an example of @Query using a Set of DateComponents Nothing will compile and after hundreds and hundreds of attempts, my hair is turning gray. Please, please, please help me. For example, if the current date is Tuesday, March 4 205, then I want to retrieve both records. Since both records contain Tuesday, March 4, then retrieve both records. Sorting works fine because the order by clause uses period which is a Double. Unfortunately, my syntax is incorrect and I don’t know the correct predicate syntax for @Query and a Set of DateComponents. Class Planner.swift file import SwiftUI import SwiftData 
 @Model class Planner { //var id: UUID = UUID() var grade: Double = 4.0 var kumi: Double = 4.0 var period: Double = 1.0 var dates: Set<DateComponents> = [] init( grade: Double = 4.0, kumi: Double = 4.0, period: Double = 1.0, dates: Set<DateComponents> = [] ) { self.grade = grade self.kumi = kumi self.period = period self.dates = dates 
 } } @Query Model snippet of code does not work The compile error is to use a Set of DateComponents, not just DateComponents. @Query(filter: #Predicate<Planner> { $0.dates = DateComponents(calendar: Calendar.current, year: 2025, month: 3, day: 4)}, sort: [SortDescriptor(\Planner.period)]) var planner: [Planner] ListView.swift image EditView.swift for record #1 DB Browser for SQLlite: record #1 (March 6, 2025 and March 4, 2025) 
 
 [{"isLeapMonth":false,"year":2025,"day":6,"month":3,"calendar":{"identifier":"gregorian","minimumDaysInFirstWeek":1,"current":1,"locale":{"identifier":"en_JP","current":1},"firstWeekday":1,"timeZone":{"identifier":"Asia\/Tokyo"}},"era":1},{"month":3,"year":2025,"day":4,"isLeapMonth":false,"era":1,"calendar":{"locale":{"identifier":"en_JP","current":1},"timeZone":{"identifier":"Asia\/Tokyo"},"current":1,"identifier":"gregorian","firstWeekday":1,"minimumDaysInFirstWeek":1}}]
 EditView.swift for record #2 DB Browser for SQLlite: record #2 (March 3, 2025 and March 4, 2025) 
 [{"calendar":{"minimumDaysInFirstWeek":1,"locale":{"current":1,"identifier":"en_JP"},"timeZone":{"identifier":"Asia\/Tokyo"},"firstWeekday":1,"current":1,"identifier":"gregorian"},"month":3,"day":3,"isLeapMonth":false,"year":2025,"era":1},{"year":2025,"month":3,"era":1,"day":4,"isLeapMonth":false,"calendar":{"identifier":"gregorian","current":1,"firstWeekday":1,"minimumDaysInFirstWeek":1,"timeZone":{"identifier":"Asia\/Tokyo"},"locale":{"current":1,"identifier":"en_JP"}}}]
 
 Any help is greatly appreciated.

Hi everyone I would like to achieve having unidirectional relationships in my SwiftData project (which I believe is possible: https://developer.apple.com/documentation/updates/swiftdata?changes=_9) but I'm afraid I'm struggling to overcome the errors I'm experiencing. For example, I have the following models: @Model final class Quota { @Attribute(.unique) var id: UUID var allowance: Int @Relationship(inverse: nil) var fish: Fish init(id: UUID = UUID(), fish: Fish, allowance: Int) { self.id = id self.fish = fish self.allowance = allowance } } @Model final class Fish { @Attribute(.unique) var id: Int var name: String init(id: Int, name: String) { self.id = id, self.name = name } } However, when I attempt to save a quota as so: let quota: Quota = .init(fish: Fish(id: 2, name: "Salmon"), allowance: 50) modelContext?.insert(quota) try save() I keep getting the following error: SwiftData.DefaultStore save failed with error: Error Domain=NSCocoaErrorDomain Code=1570 "%{PROPERTY}@ is a required value." UserInfo={NSValidationErrorObject=<NSManagedObject: 0x600002217390> (entity: Fish; id: 0x83319d001151328d <x-coredata://C76A2A64-146E-432F-A565-319B5A2F23F5/Fish/p12>; data: { id = nil; }), NSLocalizedDescription=%{PROPERTY}@ is a required value., NSValidationErrorKey=id, NSValidationErrorValue=null} %{PROPERTY}@ is a required value. However, if I set up Quota and Fish with an inverse relationship then the data saves as expected, so I'm a little confused. Is there anyone out there who can provide some guidance as to why I'm seeing this error when I try to save a record in SwiftData with no inverse relationship? I do fully understand about unidirectional vs bidirectional relationships but I have a scenario where I need the relationship to be unidirectional. Also, as a side note, the Fish record already exists in my database, but if I delete it and try to save the record I still see this error. Thank you so much in advance for any help.

Hi, I'm considering using the new SwiftData class inheritance for a new app I'm building. I have a few questions: Is it working well enough for production? I have a number of different object types in my app. Some of them are very similar, and there's always a balance to be struck when it comes to splitting them into different types using class inheritance. Are there some good advice on when to use multiple classes instead of squeezing my object types into a single class? Is there advice against using class inheritance in multiple levels (3-4)? Claes

Is there a way to move user data from UserDefaults to SwiftData when the app is in production so that people don’t lose their data. Currently my audio journals in my journal app has everything in the UserDefaults. Now this is bad for obvious reasons but I was thinking if there was a way. It’s only been 1 week since published and I have already had17 people download it.

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:

There's some logic in my app that first checks to see if a specific CloudKit record zone exists. If it doesn't, it creates the zone, and then my application continues on with its work. The way I've implemented this right now is by catching the zoneNotFound error when I call CKDatabase#recordZone(for:) (docs) and creating the zone when that happens: do { try await db.recordZone(for: zoneID) } catch let ckError as CKError where [.zoneNotFound, .userDeletedZone].contains(ckError.code) { // createZone is a helper function try await createZone(zoneID: zoneID, context: context) } This works great, but every time I do this, an error is logged in CloudKit Console, which creates a lot of noise and makes it harder to see real errors. Is there a way to do this without explicitly triggering a CloudKit error? I just found CKDatabase#recordZones(for:) (docs), which seems like it returns an empty array instead of throwing an error if the zone doesn't exist. Will calling that and looking for a non-empty array work just as well, but without logging lots of errors in the console?

In the CloudKit logs I see logs that suggest users getting QUOTA_EXCEEDED error for RecordDelete operations. { "time":"21/07/2025, 7:57:46 UTC" "database":"PRIVATE" "zone":"***" "userId":"***" "operationId":"***" "operationGroupName":"2.3.3(185)" "operationType":"RecordDelete" "platform":"iPhone" "clientOS":"iOS;18.5" "overallStatus":"USER_ERROR" "error":"QUOTA_EXCEEDED" "requestId":"***" "executionTimeMs":"177" "interfaceType":"NATIVE" "recordInsertBytes":54352 "recordInsertCount":40 "returnedRecordTypes":"_pcs_data" } I'm confused as to what this means? Why would a RecordDelete operation have recordInsertBytes? I'd expect a RecordDelete operation to never fail on quotaExceeded and how would I handle that in the app?

I am working with SwiftData and get the below error. I can't find any documentation on it to see what to fix. Any help would be appreciated. Fatal error: This relationship already has a value but it's not the target:

Hello, In our app, we’ve modeled our schema using inheritance introduced in iOS 26.0, and we’re implementing SwiftData History to re-fetch models only when necessary. @Model public class Transaction { @Attribute(.preserveValueOnDeletion) public var date: Date = Date() public var amount: Double = 0 public var memo: String? } @Model public final class Spending: Transaction { public var installmentIndex: Int = 1 public var installment: Int = 1 public var installmentID: UUID? } If data has been deleted from database, we need to check a date property to determine whether to re-fetch datas. To do this, we added the preserveValueOnDeletion attribute to date property so we could retrieve it from the History tombstone value. However, after adding this attribute, a crash occurs. There is a console log Could not cast value of type 'Swift.ReferenceWritableKeyPath<Shared.ModelSchemaV5.Transaction, Foundation.Date>' (0x106bf8328) to 'Swift.PartialKeyPath<Shared.ModelSchemaV5.Spending>' (0x1094f21d8). and error log attached StrictMoneyChecking-2025-11-07-105108.txt I also tried this in the recent SampleTrip app, and fetching all history after a deletion causes the same crash. Is this issue currently being worked on or under investigation?

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.

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)?