I am trying to get my head around SwiftData, and specifically some more "advanced" ideas that I have not seen covered in the various tutorials. Specifically, I have a class that includes a collection that may or may not contain elements. For now I am experimenting with a simple array of Date, and I don't know if I should make it an optional, or an empty array. Without SwiftData in the mix it seems like it's probably programmers choice, but I wonder if SwiftData handles those two scenarios differently, that would suggest one over the other.

Hi everyone, I’m using Core Data in several extensions (DeviceActivityMonitor, ShieldAction, and ShieldConfiguration). It works perfectly in DeviceActivityMonitor and ShieldAction. I’m able to successfully fetch data and log the correct count using a fetch request. However, when I try the same setup in the ShieldConfiguration extension, the fetch request always returns 0 results. The CoreData and App Group setup appears to be correct since the first two extensions fetch the expected data. I’ve also previously tested storing the CoreData objects separately in a JSON-FIle using FileManager and it worked without issues—though I’d prefer not to handle manual encoding/decoding if possible. The documentation mentions that the extension runs in a sandbox, restricting network requests or moving sensitive content. But shouldn’t reading data (from a shared App Group, for instance) still be possible within the sandbox, as it is the case with the Files, what is the difference there? In my case, I only need to read the data, as modifications can be handled via ShieldActionExtension. Any help would be greatly appreciated!

I have a working ValueTransformer that runs fine in simulator/device, but crashes in SwiftUI Preview. Even though they are the same code. Here is my code import Foundation final class StringBoolDictTransformer: ValueTransformer { override func transformedValue(_ value: Any?) -> Any? { guard let stringBoolDict = value as? [String: Bool] else { return nil } let nsDict = NSMutableDictionary() for (key, bool) in stringBoolDict { nsDict[key] = NSNumber(value: bool) } do { let data = try NSKeyedArchiver.archivedData(withRootObject: nsDict, requiringSecureCoding: true) return data } catch { debugPrint("Unable to convert [Date: Bool] to a persistable form: \(error.localizedDescription)") return nil } } override func reverseTransformedValue(_ value: Any?) -> Any? { guard let data = value as? Data else { return nil } do { guard let nsDict = try NSKeyedUnarchiver.unarchivedDictionary(ofKeyClass: NSString.self, objectClass: NSNumber.self, from: data) else { return nil } var result = [String: Bool]() for (key, value) in nsDict { result[key as String] = value.boolValue } return result } catch { debugPrint("Unable to convert persisted Data to [Date: Bool]: \(error.localizedDescription)") return nil } } override class func allowsReverseTransformation() -> Bool { true } override class func transformedValueClass() -> AnyClass { NSDictionary.self } } and here is the container public struct SwiftDataManager { public static let shared = SwiftDataManager() public var sharedModelContainer: ModelContainer init() { ValueTransformer.setValueTransformer( StringBoolDictTransformer(), forName: NSValueTransformerName("StringBoolDictTransformer") ) let schema = Schema([, Plan.self ]) let modelConfiguration = ModelConfiguration(schema: schema, isStoredInMemoryOnly: false) do { sharedModelContainer = try ModelContainer(for: schema, configurations: [modelConfiguration]) } catch { fatalError("Could not create ModelContainer: \(error)") } } } and the model @Model final class Plan { @Attribute(.transformable(by: StringBoolDictTransformer.self)) var dict: [String: Bool] = [:] } I would get that container and pass it in appdelegate and it works fine. I would get that container and pass it inside a #Preview and it would crash with the following: Runtime: iOS 17.5 (21F79) - DeviceType: iPhone 15 Pro CoreFoundation: *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Unacceptable type of value for attribute: property = "dict"; desired type = NSDictionary; given type = _NSInlineData; value = {length = 2, bytes = 0x7b7d}.' libsystem_c.dylib: abort() called Version 16.0 (16A242d)

CKShare provides a url that allows others to be invited. It is necessary for a potential participant to have access to this url (otherwise there is no way for them to accept the invitation). An easy solution is to send this url via the Messages application, but this is an extra step for the share owner. I have noticed that Apple's Passwords app somehow sends this url to the invited user within the Passwords app - and I wonder if this is possible with just public Apple apis, or if Apple uses some private api to achieve this.

Hi, I have a mac os app that I am developing. It is backed by a SwiftData database. I'm trying to set up cloudkit so that the app's data can be shared across the user's devices. However, I'm finding that every tutorial i find online makes it sound super easy, but only discusses it from the perspective of ios. The instructions typically say: Add the iCloud capability. Select CloudKit from its options. Press + to add a new CloudKit container, or select one of your existing ones. Add the Background Modes capability. Check the box "Remote Notifications" checkbox from its options. I'm having issue with the following: I don't see background modes showing up or remote notifications checkbox since i'm making a mac os app. If i do the first 3 steps only, when i launch my app i get an app crash while trying to load the persistent store. Here is the exact error message: Add the iCloud capability. Select CloudKit from its options. Press + to add a new CloudKit container, or select one of your existing ones. Add the Background Modes capability. Check the box "Remote Notifications" checkbox from its options. Any help would be greatly appreciated. var sharedModelContainer: ModelContainer = { let schema = Schema([One.self, Two.self]) let modelConfiguration = ModelConfiguration(schema: schema, isStoredInMemoryOnly: false) do { return try ModelContainer(for: schema, configurations: [modelConfiguration]) } catch { fatalError("Could not create ModelContainer: \(error)") } }() The fatal error in the catch block happens when i run the app.

Many years ago I put an attribute named throws in a core data entity. Now I want to extract the data and move it to a new swift data with more function. I try to rename the entity to avoid compile problems with throws being a swift keyword, now banned as a SwiftData field. I need a code path to extract from the original core data using swift. The SwiftData macros seem to choke on the throws keyword and substitute blanks. DB rename of the attribute still uses the original throws name at the code level.

I've been working with SwiftData and encountered a perplexing issue that I hope to get some insights on. When using a @Model that has a one-to-many relationship with another @Model, I noticed that if there are multiple class variables involved, SwiftData seems to struggle with correctly associating each variable with its corresponding data. For example, in my code, I have two models: Book and Page. The Book model has a property for a single contentPage and an optional array of pages. However, when I create a Book instance and leave the pages array as nil, iterating over pages unexpectedly returns the contentPage instead. You can check out the code for more details here. Has anyone else faced this issue or have any suggestions on how to resolve it? Any help would be greatly appreciated! I dont understand. How does using appended help here? I am not adding anything to the array. Here is the summary The following code defines two SwiftData models: Book and Page. In the Book class, there is a property contentPage of type Page, and an optional array pages that holds multiple Page instances. @Model class Book { var id = UUID() var title: String var contentPage: Page var pages: [Page]? init(id: UUID = UUID(), title: String, contentPage: Page) { self.id = id self.title = title self.contentPage = contentPage contentPage.book = self } func addPage(page: Page) { if pages == nil { pages = [] } page.book = self pages?.append(page) } } enum PageType: String, Codable { case contentsPage = "Contents" case picturePage = "Picture" case textPage = "Text" case blankPage = "Blank" } @Model class Page { var id = UUID() var pageType: PageType var pageNumber: Int var content: String var book: Book? init(id: UUID = UUID(), pageType: PageType, content: String, pageNumber: Int) { self.id = id self.pageType = pageType self.pageNumber = pageNumber self.content = content } } Observed Behavior: With the code above, I created a Book instance and populated all fields except for the pages, which was left as nil. However, when I attempt to iterate over the pages, I receive the contentPage instead. This indicates that there may be an issue with how SwiftData handles these associations. Expected behavior - when iterating over pages I should not see contentPage since it is a separate property

I frequently referred to Apple’s tutorial on SwiftData in Swift, but recently I haven’t been able to access it. Is there a reason why? Create, update, and delete data - De velop in Swift Tutorials https://developer.apple.com/tutorials/develop-in-swift/create-update-and-delete-data

I am currently developing an iOS app with a new feature that utilizes Quick Start for data migration between devices. We are testing this in a test environment using an app distributed via TestFlight. However, we are encountering an issue where the app installed on the pre-migration device (distributed via TestFlight) does not transfer to the post-migration device. Could this issue be related to the fact that the app was distributed via TestFlight? Is there any restriction where only apps released via the App Store can be migrated using Quick Start? We would appreciate it if you could provide some insights into the cause of this issue and any alternative testing methods.

Is this Relationship correct? Does this cause a circular reference? This runs on 18 but crashes on 17 in the swift data internals. @Model final class Item { @Attribute(.unique) var id: UUID var date: Date @Relationship(deleteRule: .nullify, inverse: \Summary.item) var summary: Summary? init(date: Date = Date.now) { self.id = UUID() self.date = Calendar.current.startOfDay(for: date) self.summary = Summary(self) } } @Model final class Summary { @Attribute(.unique) var id = UUID() @Relationship var item: Item? init(_ item: Item) { self.item = item } }

I have an app that uses Core Data. I'm switching to SwiftData but it looks like the sqlite files are stored in separate places in the application file directory so my SwiftData files aren't reading the CoreData store. I'm not sure why it's not reading from the same location. Is there something I'm missing? Here's an example of the paths that I see when I write information to the debug console: SwiftData Path: file:///Users/dougthiele/Library/Developer/CoreSimulator/Devices/52CE32F8-F6A9-4825-8027-994DBE47173C/data/Containers/Data/Application/63E9B61D-64B8-4D2D-A02C-3C306688F354/Documents/[Data File Name].sqlite Core Data Path: file:///Users/dougthiele/Library/Developer/CoreSimulator/Devices/52CE32F8-F6A9-4825-8027-994DBE47173C/data/Containers/Data/Application/96A5961B-54DD-43A9-A4C3-661B439D91AE/Documents/[Data File Name].sqlite

I'm seeing these errors in the console when calling ModelContainer(for:migrationPlan:configurations) for iOS 18: error: Attempting to retrieve an NSManagedObjectModel version checksum while the model is still editable. This may result in an unstable verison checksum. Add model to NSPersistentStoreCoordinator and try again. CoreData: error: Attempting to retrieve an NSManagedObjectModel version checksum while the model is still editable. This may result in an unstable verison checksum. Add model to NSPersistentStoreCoordinator and try again. Is this anything to be concerned about? (Side note: "version" is misspelled in "verison checksum")

I have two contexts, MAIN and VIEW. I construct an object in MAIN and it appears in VIEW (which I use to display it in the UI). Then I delete the object in MAIN. Because the UI holds a reference to the object in VIEW, VIEW records it as a pending delete (Problem 1). I don't understand why it does this nor can I find this behaviour documented. Docs for deletedObjects say "objects that will be removed from their persistent store during the next save". This has already happened! (Problem 2) Then I rollback the VIEW context, and the object is resurrected. awakeFromInsert is called again. While the object (correctly) does not appear in a freshly executed fetch request, it does appear in the @FetchRequest of the SwiftUI View which is now displaying stale data. I cannot figure out how to get SwiftUI to execute the fetch request again (I know I can force regeneration of the UI, but would like to avoid this). This is self-contained demonstration of the problem that can be run in a Playground. Press Create, then Delete (note console output), then Rollback (note console output, and that element count changes from 0 to 1 in the UI) import CoreData import SwiftUI @objc(TestEntity) class TestEntity : NSManagedObject, Identifiable{ @NSManaged var id : UUID? override func awakeFromInsert() { print("Awake from insert") if id == nil { // Avoid resetting ID when we resurrect the phantom delete self.id = UUID() } super.awakeFromInsert() } class func add(in context: NSManagedObjectContext) -> UUID { let id = UUID() context.performAndWait { let mo = TestEntity(context: context) mo.id = id } return id } class func fetch(in context: NSManagedObjectContext) -> [TestEntity] { let fr = TestEntity.fetchRequest() return try! context.fetch(fr) as! [TestEntity] } } class CoreDataStack { // Main is attached to the store var main : NSManagedObjectContext! // View is a child context of main and used to display the UI var view : NSManagedObjectContext! // Set up a simple entity with an ID attribute func getEntities() -> [NSEntityDescription] { let testEntity = NSEntityDescription() testEntity.managedObjectClassName = "TestEntity" testEntity.name = "TestEntity" let idAttribute = NSAttributeDescription() idAttribute.name = "id" idAttribute.type = .uuid testEntity.properties.append(idAttribute) return [testEntity] } init() { let model = NSManagedObjectModel() model.entities = getEntities() let container = NSPersistentContainer(name: "TestModel", managedObjectModel: model) let description = NSPersistentStoreDescription() description.type = NSInMemoryStoreType container.persistentStoreDescriptions = [description] container.loadPersistentStores { desc, error in if error != nil { fatalError("Failed to set up coredata") } } main = container.viewContext view = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType) view.automaticallyMergesChangesFromParent = true view.parent = main } func create() { let entityId = TestEntity.add(in: main) main.performAndWait { try! main.save() } } func delete() { main.performAndWait { if let mo = TestEntity.fetch(in: main).first { main.delete(mo) try! main.save() } } self.view.perform { // We only find that we have a pending delete here if we hold a reference to the object, e.g. in the UI via @FetchRequest if(self.view.deletedObjects.count != 0) { print("!!! view has a pending delete, even though main has saved the delete !!!") } } } func rollback() { self.view.perform { self.view.rollback() // PROBLEM We now have a resurrected object. Note that awakeFromInsert // was called again. } } } import SwiftUI import PlaygroundSupport let stack = CoreDataStack() struct ContentView: View { @FetchRequest(sortDescriptors: []) private var entities: FetchedResults<TestEntity> @State var renderID = UUID() var body: some View { VStack { Text("\(entities.count) elements") Button("Create") { stack.create() } Button("Delete") { stack.delete() } Button("Rollback") { stack.rollback() // PROBLEM After rollback we get the element displaying in // the UI again, even though it isn't present in a freshly // executed fetch request. // The @FetchRequest is picking up the resurrected TestEntity in view // But not actually issuing a fetch. self.renderID = UUID() entities.nsPredicate } }.id(renderID) } } //stack.execute() let view = ContentView() .environment(\.managedObjectContext, stack.view) PlaygroundPage.current.setLiveView(view)

I have an iOS app that writes files to its iCloud ubiquity container. The container is specified in Signing & Capabilities as iCloud.com.myappbusiness.myappid where "com.myappbusiness.myappid" is the bundle identifier. It works most of the time but for some users (less than 1%) it stops working at some point, most likely after any update of my app. Device reboot or app reinstallation does not help. What seems to help is turning off iCloud for the app in the iOS Settings (at which point the app saves files to the device locally) and then turning it on again. I cannot replicate the issue and have to rely on user feedback. I have tried various fixes over the past half a year, added retries after timeout, error handlers, tracing, etc. But the error always appears to someone after another app update. I have narrowed it down to the three lines of code below that check for the existence of the app iCloud container: NSFileManager* fileManager = [[NSFileManager alloc] init]; NSURL* containerUrl = [[fileManager URLForUbiquityContainerIdentifier:nil] URLByAppendingPathComponent:@"Documents"]; BOOL doesExist = [fileManager fileExistsAtPath:containerUrl.path]; doesExist returns NO when the issue happens. I.e. the app does not see its container and it looks like it does not exist. The folder should exist as this happens to long term users that have used the app before. Regarding the containerUrl, I can see it in the log that I get from the affected users and it is the correct path to the container, e.g. /private/var/mobile/Library/Mobile Documents/iCloud~com~myappbusiness~myappid/Documents I have tried the code above as it is and also within a file coordinator handler: [[[NSFileCoordinator alloc] initWithFilePresenter:nil] coordinateWritingItemAtURL:targetFileUrl options:NSFileCoordinatorWritingForReplacing error:&error byAccessor:^(NSURL * _Nonnull newURL) { ... the code here ... }]; I have run out of ideas what else to try. Is there anything obviously wrong with this approach or am I missing something in the code here? Is this a permission issue? Do I need to recreate the Documents folder if it's not accessible?

Currently, I am planning to add a new feature to my app that allows multiple users to collaboratively manage a single legder. Initially, I chose SwiftData with iCloud for development, so I wanted to inquire whether SwiftData currently supports data sharing among multiple users through iCloud. If it does not, should I transition entirely to Core Data, or is it feasible to allow Core Data and SwiftData to work together?

Presently, I am encountering an issue with SwiftData. For instance, I have a SwiftData class Ledger that encompasses an array of SingleTransaction, which is also a SwiftData class. Here is the question: when I save a Ledger, how can I discern that the .NSManagedObjectContextDidSave notification was triggered by saving the Ledger and not by saving a SingleTransaction? This distinction is crucial to circumvent unnecessary updates. I attempted the following syntax, but Xcode indicates that Cast from NSManagedObject to unrelated type Ledger always fails. List {...} .onReceive( NotificationCenter .default .publisher(for: .NSManagedObjectContextDidSave) .receive(on: DispatchQueue.main), perform: { notification in if let userInfo = notification.userInfo, let updatedObjects = userInfo[NSUpdatedObjectsKey] as? Set<NSManagedObject> { if updatedObjects.contains(where: { $0 is Ledger }) { fetchLedgers() } } } ) What can I do?

Dear community !!! I'm brand new in SwiftUI development. I created an app, I was almost at the end with fine tuning when I got weird behaviours with the iOS 18 version when using Swift Data. I think I'm part of the problem but I can not figure out how to solve it. I've searched, spent so many hours and feel a bit disappointed not succeeding. Here is my first problem : I've two models : @Model class Song: Codable { var uuid: UUID = UUID() var text: String = "" var creationDate: Date = Date.now var updatingDate: Date = Date.now var status: Int = 0 var nbRead: Int = 0 var speed: Float = 0.5 var language: String = "" enum CodingKeys: CodingKey { case uuid, text, creationDate, updatingDate, status, nbRead, speed, language } @Relationship(inverse: \Genre.songs) var genres: [Genre]? ... } and @Model class Genre { //var uuid: UUID var name: String = "" var color: String = "Red" var songs: [Song]? init( name: String, color: String) { //self.uuid = uuid self.name = name self.color = color } } I want to list all songs organised by sections : import SwiftData import SwiftUI struct SongsListView: View { private var searchingText: String @Environment(\.modelContext) private var modelContext @Query(sort: \Genre.name) private var genres: [Genre] @Query var songs : [Song] init(searchText: String) { if !searchText.isEmpty { let predicate = #Predicate<Song> { song in song.text.localizedStandardContains(searchText) } _songs = Query(filter: predicate) } searchingText = searchText } var body: some View { HStack{ List{ if !songs.isEmpty { ForEach(genres, id: \.name){ genre in Section(header: Text(genre.name)){ ForEach (songs){song in if let songGenres = song.genres { if songGenres.contains(genre){ NavigationLink { SongView(song: song) } label: { Text(song.text) } } } } } } .onDelete { indexSet in indexSet.forEach { index in let song = songs[index] modelContext.delete(song) } } Section(header: Text("Without Genre")) { ForEach (songs){song in if let songGenres = song.genres { if songGenres.isEmpty{ NavigationLink { SongView(song: song) } label: { Text(song.text) } } } } .onDelete { indexSet in indexSet.forEach { index in let song = songs[index] modelContext.delete(song) } } } } } .scrollContentBackground(.hidden) } } } On iOS 17, creating a new song adds it directly to the list in the Without Genre section. On iOS 18, it takes around 30 seconds to be added. I did a video, and I have a demo project to illustrate if necessary. Thanks a lot for any hint, advice !

I'm using Swift Data for an app that requires iOS 18. All of my models conform to a protocol that guarantees they have a 'serverID' String variable. I wrote a function that would allow me to pass in a serverID String and have it fetch the model object that matched. Because I am lazy and don't like writing the same functions over and over, I used a Self reference so that all of my conforming models get this static function. Imagine my model is called "WhatsNew". Here's some code defining the protocol and the fetching function. protocol RemotelyFetchable: PersistentModel { var serverID: String { get } } extension WhatsNew: RemotelyFetchable {} extension RemotelyFetchable { static func fetchOne(withServerID identifier: String, inContext modelContext: ModelContext) -> Self? { var fetchDescriptor = FetchDescriptor<Self>() fetchDescriptor.predicate = #Predicate<Self> { $0.serverID == identifier } do { let allModels = try modelContext.fetch(fetchDescriptor) return allModels.first } catch { return nil } } } Worked great! Or so I thought... I built this and happily ran a debug build in the Simulator and on devices for months while developing the initial version but when I went to go do a release build for TestFlight, that build reliably crashed on every device with a message like this: SwiftData/DataUtilities.swift:65: Fatal error: Couldn't find \WhatsNew. on WhatsNew with fields [SwiftData.Schema.PropertyMetadata(name: "serverID", keypath: \WhatsNew., defaultValue: nil, metadata: Optional(Attribute - name: , options: [unique], valueType: Any, defaultValue: nil, hashModifier: nil)), SwiftData.Schema.PropertyMetadata(name: "title", keypath: \WhatsNew., defaultValue: nil, metadata: nil), SwiftData.Schema.PropertyMetadata(name: "bulletPoints", keypath: \WhatsNew.)>, defaultValue: nil, metadata: nil), SwiftData.Schema.PropertyMetadata(name: "dateDescription", keypath: \WhatsNew., defaultValue: nil, metadata: nil), SwiftData.Schema.PropertyMetadata(name: "readAt", keypath: \WhatsNew.)>, defaultValue: nil, metadata: nil)] It seems (cannot confirm) that something in the release build optimization process is stripping out some metadata / something about these models that makes this predicate crash. Tested on iOS 18.0 and 18.1 beta. How can I resolve this? I have two dozen types that conform to this protocol. I could manually specialize this function for every type myself but... ugh.

I have a @Model class that is comprised of a String and a custom Enum. It was working until I added raw String values for the enum cases, and afterwards this error and code displays when opening a view that uses the class: { @storageRestrictions(accesses: _$backingData, initializes: _type) init(initialValue) { _$backingData.setValue(forKey: \.type, to: initialValue) _type = _SwiftDataNoType() } get { _$observationRegistrar.access(self, keyPath: \.type) return self.getValue(forKey: \.type) } set { _$observationRegistrar.withMutation(of: self, keyPath: \.type) { self.setValue(forKey: \.type, to: newValue) } } } Thread 1: EXC_BREAKPOINT (code=1, subcode=0x1cc165d0c) I removed the String raw values but the error persists. Any guidance would be greatly appreciated. Below is replicated code: @Model class CopingSkillEntry { var stringText: String var case: CaseType init(stringText: String, case: CaseType) { self.stringText = stringText self.case = case } } enum CaseType: Codable, Hashable { case case1 case case1 case case3 }

I have an app that uses Member as a @Model Class name. When I installed Xcode 16, Member was not allowed and failed in the Build, so I had to rename the class. If I pass this patch to the app store, my users will lose data. Do you have any suggestions?