Hello, I am building a pretty large database (~40MB) to be used in my SwiftData iOS app as read-only. While inserting and updating the data, I noticed a substantial increase in size (+ ~10MB). A little digging pointed to ACHANGE and ATRANSACTION tables that apparently are dealing with Persistent History Tracking. While I do appreciate the benefits of that, I prefer to save space. Could you please point me in the right direction?

I have a document based SwiftData app in which I would like to implement a persistent cache. For obvious reasons, I would not like to store the contents of the cache in the documents themselves, but in my app's data directory. Is a use case, in which a document based SwiftData app uses not only the ModelContainers from the currently open files, but also a ModelContainer writing a database file in the app's documents directory (for cache, settings, etc.) supported? If yes, how can you inject two different ModelContexts, one tied to the currently open file and one tied to the local database, into a SwiftUI view?

Hi guys, also those at Apple, I love what you all do and make, long time Linux user switched since silicon. But is there perhaps any timeline on improving the interaction between iCloud and git? Perhaps it is on me to check beforehand, but I enabled Desktop & Doc sync on iCloud (which included some git repos) and these now malfunction completely. Bad object errors, lost wheels, insanely long syncing, and worst of all - randomly removed environment variables! I only noticed when random stuff stopped working out of the blue; only after re-configuring zsh and doing scorched earth on brew did it click. I mean, there is a '.nosync' flaggy thing to add to dirs, but it isn't even officially supported. Moreover, when trying to disable sync for docs, it will delete local repos! So either it's disabling and starting all over again, or waiting for the sync to finish (which breaks things) and going through a long restoration process. I don't expect iCloud for the average Joe to be super specced for developers, but perhaps there could be room for some minor improvements that would at least prevent git repositories from completely breaking, e.g. just ignoring them or not syncing certain folder/file types. Restoring the whole thing (if even possible) is an extremely long and tedious process. Sorry for the rant, but I feel this might be appreciated. One of the things I like about this ecosystem, proprietary it is, is the seemliness and easy of use. If iCloud Drive is advertised as 'it will work', it's only fair that this would apply to developers too (and that they are not required to check beforehand whether it will break all of their git repositories). Or it is just me getting old. :) Cheers, Frans

Hi all, I am using SwiftData and cloudkit and I am having an extremely persistent bug. I am building an education section on a app that's populated with lessons via a local JSON file. I don't need this lesson data to sync to cloudkit as the lessons are static, just need them imported into swiftdata so I've tried to use the modelcontainer like this: static func createSharedModelContainer() -> ModelContainer { // --- Define Model Groups --- let localOnlyModels: [any PersistentModel.Type] = [ Lesson.self, MiniLesson.self, Quiz.self, Question.self ] let cloudKitSyncModels: [any PersistentModel.Type] = [ User.self, DailyTip.self, UserSubscription.self, UserEducationProgress.self // User progress syncs ] However, what happens is that I still get Lesson and MiniLesson record types on cloudkit and for some reason as well, whenever I update the data models or delete and reinstall the app on simulator, the lessons duplicate (what seems to happen is that a set of lessons comes from the JSON file as it should), and then 1-2 seconds later, an older set of lessons gets synced from cloudkit. I can delete the old set of lessons if I just delete the lessons and mini lessons record types, but if I update the data model again, this error reccurrs. Sorry, I don't know if I managed to explain this well but essentially I just want to stop the lessons and minilessons from being uploaded to cloudkit as I think this will fix the problem. Am I doing something wrong with the code?

SwiftData crashes 100% when fetching history of a model that contains an optional codable property that's updated: SwiftData/Schema.swift:389: Fatal error: Failed to materialize a keypath for someCodableID.someID from CrashModel. It is possible that this path traverses a type that does not work with append(), please file a bug report with a test. Would really appreciate some help or even a workaround. Code: import Foundation import SwiftData import Testing struct VaultsSwiftDataKnownIssuesTests { @Test func testCodableCrashInHistoryFetch() async throws { let container = try ModelContainer( for: CrashModel.self, configurations: .init( isStoredInMemoryOnly: true ) ) let context = ModelContext(container) try SimpleHistoryChecker.hasLocalHistoryChanges(context: context) // 1: insert a new value and save let model = CrashModel() model.someCodableID = SomeCodableID(someID: "testid1") context.insert(model) try context.save() // 2: check history it's fine. try SimpleHistoryChecker.hasLocalHistoryChanges(context: context) // 3: update the inserted value before then save model.someCodableID = SomeCodableID(someID: "testid2") try context.save() // The next check will always crash on fetchHistory with this error: /* SwiftData/Schema.swift:389: Fatal error: Failed to materialize a keypath for someCodableID.someID from CrashModel. It is possible that this path traverses a type that does not work with append(), please file a bug report with a test. */ try SimpleHistoryChecker.hasLocalHistoryChanges(context: context) } } @Model final class CrashModel { // optional codable crashes. var someCodableID: SomeCodableID? // these actually work: //var someCodableID: SomeCodableID //var someCodableID: [SomeCodableID] init() {} } public struct SomeCodableID: Codable { public let someID: String } final class SimpleHistoryChecker { static func hasLocalHistoryChanges(context: ModelContext) throws { let descriptor = HistoryDescriptor<DefaultHistoryTransaction>() let history = try context.fetchHistory(descriptor) guard let last = history.last else { return } print(last) } }

The stuff I've found by searching has confused me, so hopefully someone can help simplify it for me? I have an app (I use it for logging which books I've given away), and I could either add a bunch of things to the app, or I could have another app (possibly a CLI tool) to generate some reports I'd like.

When I try to promote schema to production, I get following error: Cannot promote schema with empty type 'workspace', please delete the record type before attempting to migrate the schema again However, in hierarchical root record sharing, I think it should be completely legit use case where there is empty root record (in my case workspace) to which other records reference through ->parent reference. Am I missing something? Is this weird constraint imposed on CloudKit?

I have a simple model @Model final class Movie: Identifiable { #Index\<Movie\>(\[.name\]) var id = UUID() var name: String var genre: String? init(name: String, genre: String?) { self.name = name self.genre = genre } } I turned on SQL debugging by including '-com.apple.CoreData.SQLDebug 3' argument on launch. When I fetch the data using the following code, it selects 3 records initially, but then also selects each record individually even though I am not referencing any other attributes. var fetchDescriptor = FetchDescriptor\<Movie\>() fetchDescriptor.propertiesToFetch = \[.id, .name\] fetchDescriptor.fetchLimit = 3 do { print("SELECT START") movies = try modelContext.fetch(fetchDescriptor) print("SELECT END") } catch { print("Failed to load Movie model.") } I see it selecting the 3 rows initially, but then it selects each one separately. Why would it do this on the initial fetch? I was hoping to select the data that I want to display and let the system select the entire record only when I access a variable that I did not initially fetch. CoreData: annotation: fetch using NSSQLiteStatement <0x600002158af0> on entity 'Movie' with sql text 'SELECT 1, t0.Z_PK, t0.ZID, t0.ZNAME FROM ZMOVIE t0 LIMIT 3' returned 3 rows with values: ( "<NSManagedObject: 0x600002158d70> (entity: Movie; id: 0xa583c7ed484691c1 <x-coredata://71E60F4C-1A40-4DB7-8CD1-CD76B4C11949/Movie/p1>; data: <fault>)", "<NSManagedObject: 0x600002158d20> (entity: Movie; id: 0xa583c7ed482691c1 <x-coredata://71E60F4C-1A40-4DB7-8CD1-CD76B4C11949/Movie/p2>; data: <fault>)", "<NSManagedObject: 0x600002158f00> (entity: Movie; id: 0xa583c7ed480691c1 <x-coredata://71E60F4C-1A40-4DB7-8CD1-CD76B4C11949/Movie/p3>; data: <fault>)" ) CoreData: annotation: fetch using NSSQLiteStatement <0x600002154d70> on entity 'Movie' with sql text 'SELECT 0, t0.Z_PK, t0.Z_OPT, t0.ZGENRE, t0.ZID, t0.ZNAME FROM ZMOVIE t0 WHERE t0.Z_PK = ? ' returned 1 rows CoreData: annotation: with values: ( "<NSSQLRow: 0x600000c89500>{Movie 1-1-1 genre=\"Horror\" id=4C5CB4EB-95D7-4DC8-B839-D4F2D2E96ED0 name=\"A000036\" and to-manys=0x0}" ) This all happens between the SELECT START and SELECT END print statements. Why is it fulfilling the faults immediately?

After copying and inserting instances I am getting strange duplicate values in arrays before saving. My models: @Model class Car: Identifiable { @Attribute(.unique) var name: String var carData: CarData func copy() -> Car { Car( name: "temporaryNewName", carData: carData ) } } @Model class CarData: Identifiable { var id: UUID = UUID() var featuresA: [Feature] var featuresB: [Feature] func copy() -> CarData { CarData( id: UUID(), featuresA: featuresA, featuresB: featuresB ) } } @Model class Feature: Identifiable { @Attribute(.unique) var id: Int @Attribute(.unique) var name: String @Relationship( deleteRule:.cascade, inverse: \CarData.featuresA ) private(set) var carDatasA: [CarData]? @Relationship( deleteRule:.cascade, inverse: \CarData.featuresB ) private(set) var carDatasB: [CarData]? } The Car instances are created and saved to SwiftData, after that in code: var fetchDescriptor = FetchDescriptor<Car>( predicate: #Predicate<Car> { car in car.name == name } ) let cars = try! modelContext.fetch( fetchDescriptor ) let car = cars.first! print("car featuresA:", car.featuresA.map{$0.name}) //prints ["green"] - expected let newCar = car.copy() newCar.name = "Another car" newcar.carData = car.carData.copy() print("newCar featuresA:", newCar.featuresA.map{$0.name}) //prints ["green"] - expected modelContext.insert(newCar) print("newCar featuresA:", newCar.featuresA.map{$0.name}) //prints ["green", "green"] - UNEXPECTED! /*some code planned here modifying newCar.featuresA, but they are wrong here causing issues, for example finding first expected green value and removing it will still keep the unexpected duplicate (unless iterating over all arrays to delete all unexpected duplicates - not optimal and sloooooow).*/ try! modelContext.save() print("newCar featuresA:", newCar.featuresA.map{$0.name}) //prints ["green"] - self-auto-healed??? Tested on iOS 18.2 simulator and iOS 18.3.1 device. Minimum deployment target: iOS 17.4 The business logic is that new instances need to be created by copying and modifying previously created ones, but I would like to avoid saving before all instances are created, because saving after creating each instance separately takes too much time overall. (In real life scenario there are more than 10K objects with much more properties, updating just ~10 instances with saving takes around 1 minute on iPhone 16 Pro.) Is this a bug, or how can I modify the code (without workarounds like deleting duplicate values) to not get duplicate values between insert() and save()?

Hi ! Would anyone know (if possible) how to create backup files to export and then import from the data recorded by SwiftData? For those who wish, here is a more detailed explanation of my case: I am developing a small management software with customers and events represented by distinct classes. I would like to have an "Export" button to create a file with all the instances of these 2 classes and another "Import" button to replace all the old data with the new ones from a previously exported file. I looked for several solutions but I'm a little lost...

On the macOS platform, I am planning to use the combination of NSFileProviders Custom Action and userInfo to implement custom context menus. However, the NSExtensions FileProviders Action Activation Rule in info does not work as long as it is related to userInfo. Are there any restrictions on the use of this userInfo? keepDownloaded is bool value

I'm writing some tests to confirm the behavior of my app. White creating a model actor to delete objects I realized that ModelContext.model(for:) does return objects that are deleted. I was able to reproduces this with this minimal test case: @Model class Activity { init() {} } struct MyLibraryTests { let modelContainer = try! ModelContainer( for: Activity.self, configurations: ModelConfiguration( isStoredInMemoryOnly: true ) ) init() throws { let context = ModelContext(modelContainer) context.insert(Activity()) try context.save() } @Test func modelForIdAfterDelete() async throws { let context = ModelContext(modelContainer) let id = try context.fetch(FetchDescriptor<Activity>()).first!.id context.delete(context.model(for: id) as! Activity) try context.save() let result = context.model(for: id) as? Activity #expect(result == nil) // Expectation failed: (result → MyLibrary.Activity) == nil } @Test func fetchDescriptorAfterDelete() async throws { let context = ModelContext(modelContainer) let id = try context.fetch(FetchDescriptor<Activity>()).first!.id context.delete(context.model(for: id) as! Activity) try context.save() let result = try context.fetch( FetchDescriptor<Activity>(predicate: #Predicate { $0.id == id }) ).first #expect(result == nil) } } Here I create a new context, insert an model and save it. The test modelForIdAfterDelete does fail, as result still contains the deleted object. I also tried to check #expect(result!.isDeleted), but it is also false. With the second test I use a FetchDescriptor to retrieve the object by ID and it correctly returns nil. Shouldn't both methods use a consistent behavior?

I'm building a photo editing app with a token-based subscription system using RevenueCat and StoreKit. Users purchase subscriptions that grant tokens for AI generations. There are no user accounts, the app is fully anonymous. Currently, I generate an anonymous account ID via RevenueCat SDK and store it in iCloud Keychain. This allows users on the same iCloud account to restore both their subscription and token balance across devices. However, users on a different iCloud account can restore their subscription via Apple, but their token balance is lost because there's no way to link the anonymous IDs. The problem is that if a user switches iCloud accounts or gets a new device without the same iCloud, their purchased tokens are orphaned. The subscription restores fine through Apple, but the token balance tied to the old anonymous ID becomes inaccessible. I have a few constraints: no user accounts, no email or phone sign-in, must work across devices owned by the same person, and must comply with App Store guidelines. My questions are: Is iCloud Keychain the right tool for this, or is there a better approach? Would CloudKit with an anonymous record zone be more appropriate? Are there any recommended patterns for persisting consumable balances tied to anonymous users across device migrations? Any guidance would be appreciated.

Trying to support undo & redo in an app that utilizes Swift Data and as with anything other than provided simplistic Apple demo examples the experience is not great. The problem: Im trying to build functionality that allows users to add items to an item group, where item and item group have a many-to-many relationship e.g. item group can hold many items and items can appear in multiple groups. When trying to do so with relatively simple setup of either adding or removing item group from items relationship array, I am pretty consistently met with a hard crash after performing undo & redo. Sometimes it works the first few undo & redos but 95% of the time would crash on the first one. Could not cast value of type 'Swift.Optional<Any>' (0x20a676be0) to 'Swift.Array<App.CodableStructModel>' (0x207a2bc08). Where CodableStructModel is a Codable Value type inside Item. Adding and removing this relationship should be undoable & redoable as typical for Mac interaction and is "supported" by SwiftData by default, meaning that the developer has to actively either wholly opt out of undo support in their modelContainer setup or do it on a per action scale with the only thing I know of: modelContext.processPendingChanges() modelContext.undoManager?.disableUndoRegistration() ..... modelContext.processPendingChanges() modelContext.undoManager?.enableUndoRegistration() General rant on SwiftData: Random crashes, inconsistencies, random cryptic errors thrown by the debugger and general lack of production level stability. Each update breaks something new and there is very little guidance and communication from the Swift Data team on how to adapt and more importantly consideration for developers that have adopted Swift Data. If SwiftData is not ready for production, it would go a long way to clearly communicate that and mark it as Beta product.

I found that the enumerateItems function is only called when a directory is opened for the first time. If the same directory is opened in the future, enumerateItems will not be called again. Can you set or actively trigger the call to the enumerateItems function

CloudKit CKRecordZone Deletion Issue Problem: CloudKit record zones deleted via CKDatabase.modifyRecordZones(deleting:) or CKModifyRecordZonesOperation are successfully removed but then reappear. I suspect they are automatically reinstated by CloudKit sync, despite successful deletion confirmation. Environment: SwiftData with CloudKit integration Custom CloudKit zones created for legacy zone-based sharing Observed Behavior: Create custom zone (e.g., "TestZone1") via CKDatabase.modifyRecordZones(saving:) Copy records to zone for sharing purposes Delete zone using any CloudKit deletion API - returns success, no errors Immediate verification: Zone is gone from database.allRecordZones() After SwiftData/CloudKit sync or app restart: Zone reappears Reproduction: Tested with three different deletion methods - all exhibit same behaviour: modifyRecordZones(deleting:) async API CKModifyRecordZonesOperation (fire-and-forget) CKModifyRecordZonesOperation with result callbacks Zone deletion succeeds, change tokens (used to track updates to shared records) cleaned up But zones are restored presumably by CloudKit background sync Expected: Deleted zones should remain deleted Actual: Zones are reinstated, creating orphaned zones

Hi everyone, I’m running into a breaking issue with SwiftData automatic CloudKit syncing on iOS 26, and I'm trying to determine if this is a known regression or a new configuration requirement I missed. The Setup: My setup is extremely standard; I am using the default configuration exactly as described in Apple's documentation here: https://developer.apple.com/documentation/swiftdata/syncing-model-data-across-a-persons-devices The schema is very simple: A single @Model class. No relationships. The Issue: Prior to iOS 26, this exact app was successfully syncing data between devices and to iCloud without issues. Immediately after the iOS 26 update, syncing stopped completely. I haven't changed any code, but when I check the CloudKit Console, I am seeing some BAD_REQUEST errors during sync attempts. Since I am using the default SwiftData sync (and not manual CKRecord handling), I’m not sure how my client code could be triggering a bad request unless the schema requirements have changed under the hood. Questions: Has anyone else seen increased BAD_REQUEST errors with SwiftData on iOS 26? Are there new entitlements or strict schema requirements introduced in iOS 26 that might cause a previously valid model to be rejected by CloudKit? Any pointers or confirmations would be appreciated. Thanks!

I'm experiencing the following error with my SwiftData container when running a build: Code=134504 "Cannot use staged migration with an unknown model version." Code Structure - Summary I am using a versionedSchema to store multiple models in SwiftData. I started experiencing this issue when adding two new models in the newest Schema version. Starting from the current public version, V4.4.6, there are two migrations. Migration Summary The first migration is to V4.4.7. This is a lightweight migration removing one attribute from one of the models. This was tested and worked successfully. The second migration is to V5.0.0. This is a custom migration adding two new models, and instantiating instances of the two new models based on data from instances of the existing models. In the initial testing of this version, no issues were observed. Issue and Steps to Reproduce Reproduction of issue: Starting from a fresh build of the publicly released V4.4.6, I run a new build that contains both Schema Versions (V4.4.7 and V5.0.0), and their associated migration stages. This builds successfully, and the container successfully migrates to V5.0.0. Checking the default.store file, all values appear to migrate and instantiate correctly. The second step in reproduction of the issue is to simply stop running the build, and then rebuild, without any code changes. This fails to initialize the model container every time afterwards. Going back to the simulator after successive builds are stopped in Xcode, the app launches and accesses/modifies the model container as normal. Supplementary Issue: I have been putting up with the same, persistent issue in the Xcode Preview Canvas of "Failed to Initialize Model Container" This is a 5 in 6 build issue, where builds will work at random. In the case of previews, I have cleared all data associated with all previews multiple times. The only difference being that the simulator is a 100% failure rate after the initial, successful initialization. I assume this is due to the different build structure of previews. Lastly, of note, the Xcode previews fail at the same line in instantiating the model container as the simulator does. From my research into this issue, people say that the Xcode preview is instantiating from elsewhere. I do have a separate model container set up specifically for canvas previews, but the error does not occur in that container, but rather the app's main container. Possible Contributing Factors & Tested Facts iOS: While I have experienced issues with SwiftData and the complier in iOS 26, I can rule that out as the issue here. This has been tested on simulators running iOS 18.6, 26.0.1, and 26.1, all encountering failures to initialize model container. While in iOS 18, subsequent builds after the successful migration did work, I did eventually encounter the same error and crash. In iOS 26.0.1 and 26.1, these errors come immediately on the second build. Container Initialization for V4.4.6 do { container = try ModelContainer( for: Job.self, JobTask.self, Day.self, Charge.self, Material.self, Person.self, TaskCategory.self, Service.self, migrationPlan: JobifyMigrationPlan.self ) } catch { fatalError("Failed to Initialize Model Container") } Versioned Schema Instance for V4.4.6 (V4.4.7 differs only by versionIdentifier) static var versionIdentifier = Schema.Version(4, 4, 6) static var models: [any PersistentModel.Type] { [Job.self, JobTask.self, Day.self, Charge.self, Material.self, Person.self, TaskCategory.self, Service.self] } Container Initialization for V5.0.0 do { let schema = Schema([Jobify.self, JobTask.self, Day.self, Charge.self, MaterialItem.self, Person.self, TaskCategory.self, Service.self, ServiceJob.self, RecurerRule.self]) container = try ModelContainer( for: schema, migrationPlan: JobifyMigrationPlan.self ) } catch { fatalError("Failed to Initialize Model Container") } Versioned Schema Instance for V5.0.0 static var versionIdentifier = Schema.Version(5, 0, 0) static var models: [any PersistentModel.Type] { [ JobifySchemaV500.Job.self, JobifySchemaV500.JobTask.self, JobifySchemaV500.Day.self, JobifySchemaV500.Charge.self, JobifySchemaV500.Material.self, JobifySchemaV500.Person.self, JobifySchemaV500.TaskCategory.self, JobifySchemaV500.Service.self, JobifySchemaV500.ServiceJob.self, JobifySchemaV500.RecurerRule.self ] } Addressing Differences in Object Names Type-aliasing: All my model types are type-aliased for simplification in view components. All types are aliased as 'JobifySchemeV446.<#Name#>' in V.4.4.6, and 'JobifySchemaV500.<#Name#>' in V5.0.0 Issues with iOS 26: My type-aliases dating back to iOS 17 overlapped with lower level objects in Swift, including 'Job' and 'Material'. These started to be an issue with initializing the model container when running in iOS 26. The type aliases have been renamed since, however the V4.4.6 build with the old names runs and builds perfectly fine in iOS 26 If there is any other code that may be relevant in determining where this error is occurring, I would be happy to add it. My current best theory is simply that I have mistakenly omitted code relevant to the SwiftData Migration.

We have an unreleased SwiftData app for iOS18+. While we were testing I saw reports on the forum about unexpected database migrations for codable arrays on iOS26.1. I'd like to ask a couple of questions: 1- Does this issue originate from the new Xcode version, or is it specific to iOS 26.1? 2- Is it possible to change our attribute so that users on older iOS versions receive the same model, preventing a migration from being triggered when they upgrade to iOS 26.1? One of our models looks like this: struct Point: Codable, Hashable { let x: Int let y: Int } @Model class Grid { private(set) var gridId: String = "" var points: [Point] = [] var updatedAt: Date = Date() private(set) var createdAt: Date = Date() #Index<Grid>([\.gridId]) ... } I can think of some options like: // 1 @Attribute(.transformable(by: CustomJsonTransformer.self)) var points: [Point] = [] // 2 @Attribute(.externalStorage) var points: [Point] = [] // 3 var points: Data = Data() // store points as data However, I'm not sure which one to use. What would you recommend to handle this, or is there a better strategy you would suggest?

I'm having some issues where only a subset of records appear in CloudKit dashboard after I have saved some records in my iOS app using NSPersistentCloudKitContainer. I have noticed that when I'm running my app using the development environment of my CloudKit container everything works smoothly and is uploaded as expected but when I'm using the production environment only a subset of records are actually uploaded. I'm pulling my hair on how to debug this. -com.apple.CoreData.CloudKitDebug and -com.apple.CoreData.SQLDebug pukes out too much info in the console for me to pinpoint any issue.