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SwiftData updates in the background are not merged in the main UI context
Hello, SwiftData is not working correctly with Swift Concurrency. And it’s sad after all this time. I personally found a regression. The attached code works perfectly fine on iOS 17.5 but doesn’t work correctly on iOS 18 or iOS 18.1. A model can be updated from the background (Task, Task.detached or ModelActor) and refreshes the UI, but as soon as the same item is updated from the View (fetched via a Query), the next background updates are not reflected anymore in the UI, the UI is not refreshed, the updates are not merged into the main. How to reproduce: Launch the app Tap the plus button in the navigation bar to create a new item Tap on the “Update from Task”, “Update from Detached Task”, “Update from ModelActor” many times Notice the time is updated Tap on the “Update from View” (once or many times) Notice the time is updated Tap again on “Update from Task”, “Update from Detached Task”, “Update from ModelActor” many times Notice that the time is not update anymore Am I doing something wrong? Or is this a bug in iOS 18/18.1? Many other posts talk about issues where updates from background thread are not merged into the main thread. I don’t know if they all are related but it would be nice to have 1/ bug fixed, meaning that if I update an item from a background, it’s reflected in the UI, and 2/ proper documentation on how to use SwiftData with Swift Concurrency (ModelActor). I don’t know if what I’m doing in my buttons is correct or not. Thanks, Axel import SwiftData import SwiftUI @main struct FB_SwiftData_BackgroundApp: App { var body: some Scene { WindowGroup { ContentView() .modelContainer(for: Item.self) } } } struct ContentView: View { @Environment(\.modelContext) private var modelContext @State private var simpleModelActor: SimpleModelActor! @Query private var items: [Item] var body: some View { NavigationView { VStack { if let firstItem: Item = items.first { Text(firstItem.timestamp, format: Date.FormatStyle(date: .omitted, time: .standard)) .font(.largeTitle) .fontWeight(.heavy) Button("Update from Task") { let modelContainer: ModelContainer = modelContext.container let itemID: Item.ID = firstItem.persistentModelID Task { let context: ModelContext = ModelContext(modelContainer) guard let itemInContext: Item = context.model(for: itemID) as? Item else { return } itemInContext.timestamp = Date.now.addingTimeInterval(.random(in: 0...2000)) try context.save() } } .buttonStyle(.bordered) Button("Update from Detached Task") { let container: ModelContainer = modelContext.container let itemID: Item.ID = firstItem.persistentModelID Task.detached { let context: ModelContext = ModelContext(container) guard let itemInContext: Item = context.model(for: itemID) as? Item else { return } itemInContext.timestamp = Date.now.addingTimeInterval(.random(in: 0...2000)) try context.save() } } .buttonStyle(.bordered) Button("Update from ModelActor") { let container: ModelContainer = modelContext.container let persistentModelID: Item.ID = firstItem.persistentModelID Task.detached { let actor: SimpleModelActor = SimpleModelActor(modelContainer: container) await actor.updateItem(identifier: persistentModelID) } } .buttonStyle(.bordered) Button("Update from ModelActor in State") { let container: ModelContainer = modelContext.container let persistentModelID: Item.ID = firstItem.persistentModelID Task.detached { let actor: SimpleModelActor = SimpleModelActor(modelContainer: container) await MainActor.run { simpleModelActor = actor } await actor.updateItem(identifier: persistentModelID) } } .buttonStyle(.bordered) Divider() .padding(.vertical) Button("Update from View") { firstItem.timestamp = Date.now.addingTimeInterval(.random(in: 0...2000)) } .buttonStyle(.bordered) } else { ContentUnavailableView( "No Data", systemImage: "slash.circle", // 􀕧 description: Text("Tap the plus button in the toolbar") ) } } .toolbar { ToolbarItem(placement: .primaryAction) { Button(action: addItem) { Label("Add Item", systemImage: "plus") } } } } } private func addItem() { modelContext.insert(Item(timestamp: Date.now)) try? modelContext.save() } } @ModelActor final actor SimpleModelActor { var context: String = "" func updateItem(identifier: Item.ID) { guard let item = self[identifier, as: Item.self] else { return } item.timestamp = Date.now.addingTimeInterval(.random(in: 0...2000)) try! modelContext.save() } } @Model final class Item: Identifiable { var timestamp: Date init(timestamp: Date) { self.timestamp = timestamp } }
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757
Apr ’25
Core Data and Background Tasks
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?
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0
881
Dec ’24
Can't deploy CloudKit schema because of empty record? Why?
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?
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590
Feb ’25
SwiftData initializing Optional Array to Empty Array
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) }
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125
Aug ’25
CloudKit console fails to query indexed records in Production
"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.
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91
Aug ’25
CloudKit Console: No Containers
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!
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137
Jun ’25
Xcode 26: Sendable checking + NSManagedObjectContext.perform in Swift 6
I have some code which handles doing some computation on a background thread before updating Core Data NSManagedObjects by using the NSManagedObjectContext.perform functions. This code is covered in Sendable warnings in Xcode 26 (beta 6) because my NSManagedObject subclasses (autogenerated) are non-Sendable and NSManagedObjectContext.perform function takes a Sendable closure. But I can't really figure out what I should be doing. I realize this pattern is non-ideal for Swift concurrency, but it's what Core Data demands AFAIK. How do I deal with this? let moc = object.managedObjectContext! try await moc.perform { object.completed = true // Capture of 'object' with non-Sendable type 'MySpecialObject' in a '@Sendable' closure try moc.save() } Thanks in advance for your help!
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131
Aug ’25
SwiftData Relationship Delete Not Working (SwiftData/PersistentModel.swift:359)
SwiftData delete isn't working, when I attempt to delete a model, my app crashes and I get the following error: SwiftData/PersistentModel.swift:359: Fatal error: Cannot remove My_App.Model2 from relationship Relationship - name: model2, options: [], valueType: Model2, destination: Model2, inverseName: models3, inverseKeypath: Optional(\Model2.models3) on My_App.Model3 because an appropriate default value is not configured. I get that it's saying I don't have a default value, but why do I need one? Isn't @Relationship .cascade automatically deleting the associated models? And onto of that, why is the error occurring within the do block, shouldn't it be caught by the catch, and printed? I have put together a sample project below. import SwiftUI import SwiftData @main struct MyApp: App { var body: some Scene { WindowGroup { ContentView() .modelContainer(for: Model3.self) } } } @Model class Model1 { var name: String @Relationship(deleteRule: .cascade, inverse: \Model2.model1) var models2: [Model2] = [] init(name: String) { self.name = name } } @Model class Model2 { var name: String var model1: Model1 @Relationship(deleteRule: .cascade, inverse: \Model3.model2) var models3: [Model3] = [] init(name: String, model1: Model1) { self.name = name self.model1 = model1 } } @Model class Model3 { var name: String var model2: Model2 init(name: String, model2: Model2) { self.name = name self.model2 = model2 } } struct ContentView: View { @Query var models1: [Model1] @Environment(\.modelContext) var modelContext var body: some View { NavigationStack { List(models1) { model1 in Text(model1.name) .swipeActions { Button("Delete", systemImage: "trash", role: .destructive) { modelContext.delete(model1) do { try modelContext.save() //SwiftData/PersistentModel.swift:359: Fatal error: Cannot remove My_App.Model2 from relationship Relationship - name: model2, options: [], valueType: Model2, destination: Model2, inverseName: models3, inverseKeypath: Optional(\Model2.models3) on My_App.Model3 because an appropriate default value is not configured. } catch { print(error.localizedDescription) } } } } .toolbar { Button("Insert", systemImage: "plus") { modelContext.insert(Model3(name: "model3", model2: Model2(name: "model2", model1: Model1(name: "model1")))) } } } } }
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1k
Jan ’25
Not able to save with SwiftData. "The file “default.store” couldn’t be opened."
I get this message when trying to save my Models. CoreData: error: SQLCore dispatchRequest: exception handling request: <NSSQLSaveChangesRequestContext: 0x303034540> , I/O error for database at /var/mobile/Containers/Data/Application/726ECA8C-6C67-4BFE-89E7-AFD8A83CAA5D/Library/Application Support/default.store. SQLite error code:1, 'no such table: ZCALENDARMODEL' with userInfo of { NSFilePath = "/var/mobile/Containers/Data/Application/726ECA8C-6C67-4BFE-89E7-AFD8A83CAA5D/Library/Application Support/default.store"; NSSQLiteErrorDomain = 1; } SwiftData.DefaultStore save failed with error: Error Domain=NSCocoaErrorDomain Code=256 "The file “default.store” couldn’t be opened." UserInfo={NSFilePath=/var/mobile/Containers/Data/Application/726ECA8C-6C67-4BFE-89E7-AFD8A83CAA5D/Library/Application Support/default.store, NSSQLiteErrorDomain=1} The App has Recipes and Calendars and the user can select a Recipe for each Calendar day. The recipe should not be referenced, it should be saved by SwiftData along with the Calendar. import SwiftUI import SwiftData enum CalendarSource: String, Codable { case created case imported } @Model class CalendarModel: Identifiable, Codable { var id: UUID = UUID() var name: String var startDate: Date var endDate: Date var recipes: [String: RecipeData] = [:] var thumbnailData: Data? var source: CalendarSource? // Computed Properties var daysBetween: Int { let days = Calendar.current.dateComponents([.day], from: startDate.midnight, to: endDate.midnight).day ?? 0 return days + 1 } var allDates: [Date] { startDate.midnight.allDates(upTo: endDate.midnight) } var thumbnailImage: Image? { if let data = thumbnailData, let uiImage = UIImage(data: data) { return Image(uiImage: uiImage) } else { return nil } } // Initializer init(name: String, startDate: Date, endDate: Date, thumbnailData: Data? = nil, source: CalendarSource? = .created) { self.name = name self.startDate = startDate self.endDate = endDate self.thumbnailData = thumbnailData self.source = source } // Convenience initializer to create a copy of an existing calendar static func copy(from calendar: CalendarModel) -> CalendarModel { let copiedCalendar = CalendarModel( name: calendar.name, startDate: calendar.startDate, endDate: calendar.endDate, thumbnailData: calendar.thumbnailData, source: calendar.source ) // Copy recipes copiedCalendar.recipes = calendar.recipes.mapValues { $0 } return copiedCalendar } // Codable Conformance private enum CodingKeys: String, CodingKey { case id, name, startDate, endDate, recipes, thumbnailData, source } required init(from decoder: Decoder) throws { let container = try decoder.container(keyedBy: CodingKeys.self) id = try container.decode(UUID.self, forKey: .id) name = try container.decode(String.self, forKey: .name) startDate = try container.decode(Date.self, forKey: .startDate) endDate = try container.decode(Date.self, forKey: .endDate) recipes = try container.decode([String: RecipeData].self, forKey: .recipes) thumbnailData = try container.decodeIfPresent(Data.self, forKey: .thumbnailData) source = try container.decodeIfPresent(CalendarSource.self, forKey: .source) } func encode(to encoder: Encoder) throws { var container = encoder.container(keyedBy: CodingKeys.self) try container.encode(id, forKey: .id) try container.encode(name, forKey: .name) try container.encode(startDate, forKey: .startDate) try container.encode(endDate, forKey: .endDate) try container.encode(recipes, forKey: .recipes) try container.encode(thumbnailData, forKey: .thumbnailData) try container.encode(source, forKey: .source) } } import SwiftUI struct RecipeData: Codable, Identifiable { var id: UUID = UUID() var name: String var ingredients: String var steps: String var thumbnailData: Data? // Computed property to convert thumbnail data to a SwiftUI Image var thumbnailImage: Image? { if let data = thumbnailData, let uiImage = UIImage(data: data) { return Image(uiImage: uiImage) } else { return nil // No image } } init(recipe: RecipeModel) { self.name = recipe.name self.ingredients = recipe.ingredients self.steps = recipe.steps self.thumbnailData = recipe.thumbnailData } } import SwiftUI import SwiftData @Model class RecipeModel: Identifiable, Codable { var id: UUID = UUID() var name: String var ingredients: String var steps: String var thumbnailData: Data? // Store the image data for the thumbnail static let fallbackSymbols = ["book.pages.fill", "carrot.fill", "fork.knife", "stove.fill"] // Computed property to convert thumbnail data to a SwiftUI Image var thumbnailImage: Image? { if let data = thumbnailData, let uiImage = UIImage(data: data) { return Image(uiImage: uiImage) } else { return nil // No image } } // MARK: - Initializer init(name: String, ingredients: String = "", steps: String = "", thumbnailData: Data? = nil) { self.name = name self.ingredients = ingredients self.steps = steps self.thumbnailData = thumbnailData } // MARK: - Copy Function func copy() -> RecipeModel { RecipeModel( name: self.name, ingredients: self.ingredients, steps: self.steps, thumbnailData: self.thumbnailData ) } // MARK: - Codable Conformance private enum CodingKeys: String, CodingKey { case id, name, ingredients, steps, thumbnailData } required init(from decoder: Decoder) throws { ... } func encode(to encoder: Encoder) throws { var container = encoder.container(keyedBy: CodingKeys.self) try container.encode(id, forKey: .id) try container.encode(name, forKey: .name) try container.encode(ingredients, forKey: .ingredients) try container.encode(steps, forKey: .steps) try container.encode(thumbnailData, forKey: .thumbnailData) } }
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885
Jan ’25
What is going on with transformable
Hi, I keep trying to use transformable to store an array of strings with SwiftData, and I can see that it is activating the transformer, but it keeps saying that I am still using NSArray instead of NSData. *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Unacceptable type of value for attribute: property = "category"; desired type = NSData; given type = Swift.__SwiftDeferredNSArray; value = ( yo, gurt ).' terminating due to uncaught exception of type NSException CoreSimulator 1010.10 - Device: iPhone 16 18.0 (6879535B-3174-4025-AD37-ED06E60291AD) - Runtime: iOS 18.0 (22A3351) - DeviceType: iPhone 16 Message from debugger: killed @Model class MyModel: Identifiable, Equatable { @Attribute(.transformable(by: StringArrayTransformer.self)) var category: [String]? @Attribute(.transformable(by: StringArrayTransformer.self)) var amenities: [String]? var image: String? var parentChunck: MyModelDataChunk_V1? init(category: [String]?, amenities: [String]?) { self.category = category self.amenities = amenities } } class StringArrayTransformer: ValueTransformer { override func transformedValue(_ value: Any?) -> Any? { print(value) guard let array = value as? [String] else { return nil } let data = try? JSONSerialization.data(withJSONObject: array, options: []) print(data) return data } override func reverseTransformedValue(_ value: Any?) -> Any? { guard let data = value as? Data else { return nil } let string = (try? JSONSerialization.jsonObject(with: data, options: [])) as? [String] print(string) return string } override class func transformedValueClass() -> AnyClass { return NSData.self } override class func allowsReverseTransformation() -> Bool { return true } static func register() { print("regitsering") ValueTransformer.setValueTransformer(StringArrayTransformer(), forName: .stringArrayTransformerName) } } extension NSValueTransformerName { static let stringArrayTransformerName = NSValueTransformerName("StringArrayTransformer") }
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112
Jul ’25
Issues during CloudKit record sharing
I am trying to implement record sharing in my project, but when I try to copy the link on the UICloudSharingController, the sheet closes and the link doesn't get copied. My CloudKitManager function: public func shareTeam(_ team: Team) -> AnyPublisher<CKShare, Error> { Future { [weak self] promise in guard let self = self else { promise(.failure(CloudKitError.unknown)) return } let record = team.toCKRecord() let share = CKShare(rootRecord: record) share[CKShare.SystemFieldKey.title] = "Join \(team.name)" as CKRecordValue share.publicPermission = .readWrite let operation = CKModifyRecordsOperation(recordsToSave: [record, share], recordIDsToDelete: nil) operation.savePolicy = .ifServerRecordUnchanged operation.qualityOfService = .userInitiated operation.modifyRecordsResultBlock = { result in switch result { case .success: promise(.success(share)) case .failure(let error): promise(.failure(error)) } } self.privateDatabase.add(operation) } .eraseToAnyPublisher() } ViewModel function: func shareTeam() { guard let selectedTeam = selectedTeam else { return } CloudKitManager.shared.shareTeam(selectedTeam) .receive(on: DispatchQueue.main) .sink { [weak self] completion in switch completion { case .finished: break case .failure(let error): self?.didError = true self?.error = error } } receiveValue: { share in let sharePresenter = SharePresenter( share: share, container: CloudKitManager.shared.container, teamName: selectedTeam.name, rootRecord: selectedTeam.toCKRecord() ) sharePresenter.presentShareSheet() } .store(in: &cancellables) }
1
0
735
Dec ’24
Data Transfer or Upload to Cloudkit in Published Mode
So i created an App and for some time it was working fine. The app has features to show pdf to users without logging in. I needed to upload all data to cloudkit on public database. I was not having knowledge that there are 2 mode being a noob in coding so after i saved all records in development mode in cloudkit when i published my app, i was not able to see them (Reason because live mode works in Production mode). So i need help now to transfer data from development mode to production mode or any app or code that can help me upload all data in production mode.
1
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95
Mar ’25
Inheritance in SwiftData — Fatal error: Never access a full future backing data
I'm implementing SwiftData with inheritance in an app. I have an Entity class with a property name. This class is inherited by two other classes: Store and Person. The Entity model has a one-to-many relationship with a Transaction class. I can list all my Entity models in a List with a @Query annotation without a problem. However, then I try to access the name property of an Entity from a Transaction relationship, the app crashes with the following error: Thread 1: Fatal error: Never access a full future backing data - PersistentIdentifier(id: SwiftData.PersistentIdentifier.ID(backing: SwiftData.PersistentIdentifier.PersistentIdentifierBacking.managedObjectID(0x96530ce28d41eb63 <x-coredata://DABFF7BB-C412-474E-AD50-A1F30AC6DBE9/Person/p4>))) with Optional(F07E7E23-F8F0-4CC0-B282-270B5EDDC7F3) From my attempts to fix the issue, I noticed that: The crash seems related to the relationships with classes that has inherit from another class, since it only happens there. When I create new data, I can usually access it without any problem. The crash mostly happens after reloading the app. This error has been mentioned on the forum (for example here), but in a context not related with inheritance. You can find the full code here. For reference, my models looks like this: @Model class Transaction { @Attribute(.unique) var id: String var name: String var date: Date var amount: Double var entity: Entity? var store: Store? { entity as? Store } var person: Person? { entity as? Person } init( id: String = UUID().uuidString, name: String, amount: Double, date: Date = .now, entity: Entity? = nil, ) { self.id = id self.name = name self.amount = amount self.date = date self.entity = entity } } @Model class Entity: Identifiable { @Attribute(.preserveValueOnDeletion) var name: String var lastUsedAt: Date @Relationship(deleteRule: .cascade, inverse: \Transaction.entity) var operations: [Transaction] init( name: String, lastUsedAt: Date = .now, operations: [Transaction] = [], ) { self.name = name self.lastUsedAt = lastUsedAt self.operations = operations } } @available(iOS 26, *) @Model class Store: Entity { @Attribute(.unique) var id: String var locations: [Location] init( id: String = UUID().uuidString, name: String, lastUsedAt: Date = .now, locations: [Location] = [], operations: [Transaction] = [] ) { self.locations = locations self.id = id super.init(name: name, lastUsedAt: lastUsedAt, operations: operations) } } In order to reproduce the error: Run the app in the simulator. Click the + button to create a new transaction. Relaunch the app, then click on any transaction. The app crashes when it tries to read te name property while building the details view.
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219
Sep ’25
Default zone is not accessible in shared DB - cloudKit
I am trying to save to cloud kit shared database. The shared database does not allow zones to be set up. How do I save to sharedCloudDatabase without a zone? private func addItem(recordType: String, name: String) { let record = CKRecord(recordType: recordType) record[Constances.field.name] = name as CKRecordValue record[Constances.field.done] = false as CKRecordValue record[Constances.field.priority] = 0 as CKRecordValue CKContainer.default().sharedCloudDatabase.save(record) { [weak self] returnRecord, error in if let error = error { print("Error saving record: \(record[Constances.field.name] as? String ?? "No Name"): \n \(error)") return } } } The following error message prints out: Error saving record: Milk: &lt;CKError 0x15af87900: "Server Rejected Request" (15/2027); server message = "Default zone is not accessible in shared DB"; op = B085F7BA703D4A08; uuid = 87AEFB09-4386-4E43-81D7-971AAE8BA9E0; container ID = "iCloud.com.sfw-consulting.Family-List"&gt;
1
0
68
Jun ’25
Ongoing Issues with ModelActor in SwiftData?
After the significant issues with the ModelActor in iOS 18, it seemed like the ModelActor became more stable with iOS 18.1 and macOS 15.1. However, I’m still encountering problems and crashes. I wanted to ask if these issues are related to my persistence layer architecture or if they’re still inherent to the ModelActor itself. I’ve generally followed the blog posts: https://fatbobman.com/en/posts/practical-swiftdata-building-swiftui-applications-with-modern-approaches/ and https://brightdigit.com/tutorials/swiftdata-modelactor/ and aim to achieve the following: I have a single DataProvider that holds the ModelContainer and uses it to configure and initialize a single DataHandler. These are created once at app launch and injected into the SwiftUI view hierarchy as EnvironmentObjects. Since I need to access the SwiftData models not only in SwiftUI but also indirectly in ViewModels or UIKit views, all read operations on the models should go through the DataProvider (and its MainContext), while all other CRUD operations are handled centrally via the single DataHandler (executed within a single ModelActor). Additionally, I want to monitor the entire container using another ModelActor, initialized in the DataProvider, which tracks changes to objects using TransactionHistory. I’ve managed to implement this to some extent, but I’m facing two main issues: 1. ModelActor and Main Actor Requirement The ModelActor only updates SwiftUI views when initialized via the maincontext of the ModelContainer and therefore runs on the Main Actor. It would be ideal for this to work in the background, but the issue with the ModelActor that existed previously doesn’t seem to have been resolved in iOS 18.1/macOS 15.1—am I wrong about this? 2. Frequent Crashes (more severe) Crashes occur, especially when multiple windows on macOS or on iPad access the same DataHandler to update models. This often leads to crashes during read operations on models by a SwiftUI view (but not only), with logs like: error: the replacement path doesn't exist: "/var/folders/gs/8rwdjczj225d1pj046w3d97c0000gn/T/swift-generated-sources/@__swiftmacro_12SwiftDataTSI3TagC4uuID18_PersistedPropertyfMa_.swift" Can't show file for stack frame : <DBGLLDBStackFrame: 0x34d28e170> - stackNumber:1 - name:Tag.uuID.getter. The file path does not exist on the file system: /var/folders/gs/8rwdjczj225d1pj046w3d97c0000gn/T/swift-generated-sources/@__swiftmacro_12SwiftDataTSI3TagC4uuID18_PersistedPropertyfMa_.swift This error usually happens when there are multiple concurrent accesses to the DataHandler/ModelActor. However, crashes also occur sporadically during frequent accesses from a single view with an error like "the replacement path doesn't exist." It also seems like having multiple ModelActors, as in this case (one for observation and one for data changes), causes interference and instability. The app appears to crash less frequently when the observer is not initialized, but I can’t verify this—it might just be a coincidence. My Question: Am I fundamentally doing something wrong with the ModelActors or the architecture of my persistence layer?
1
0
507
Dec ’24
SwiftData crashes on fetchHistory
Hi, would it be possible that instead of crashing when calling fetchHistory that function simply throws an error instead? fetchHistory seems to crash when it cannot understand the models if they are not compatible etc… which is understandable, but it makes it really difficult to handle and debug, there's not a lot of details, and honestly I would just rather that it throws an error and let me ignore a history entry that might be useless rather than crashing the entire app. Thank you!
1
1
62
Apr ’25