I'm getting the following error message when executing the rollback method in a modelContext, what could be causing this ? SwiftData/ModelSnapshot.swift:46: Fatal error: A ModelSnapshot must be initialized with a known-keys dictionary

Hello, I am trying to get the elements from my SwiftData databse in the configuration for my widget. The SwiftData model is the following one: @Model class CountdownEvent { @Attribute(.unique) var id: UUID var title: String var date: Date @Attribute(.externalStorage) var image: Data init(id: UUID, title: String, date: Date, image: Data) { self.id = id self.title = title self.date = date self.image = image } } And, so far, I have tried the following thing: AppIntent.swift struct ConfigurationAppIntent: WidgetConfigurationIntent { static var title: LocalizedStringResource { "Configuration" } static var description: IntentDescription { "This is an example widget." } // An example configurable parameter. @Parameter(title: "Countdown") var countdown: CountdownEntity? } Countdowns.swift, this is the file with the widget view struct Provider: AppIntentTimelineProvider { func placeholder(in context: Context) -> SimpleEntry { SimpleEntry(date: Date(), configuration: ConfigurationAppIntent()) } func snapshot(for configuration: ConfigurationAppIntent, in context: Context) async -> SimpleEntry { SimpleEntry(date: Date(), configuration: configuration) } func timeline(for configuration: ConfigurationAppIntent, in context: Context) async -> Timeline<SimpleEntry> { var entries: [SimpleEntry] = [] // Generate a timeline consisting of five entries an hour apart, starting from the current date. let currentDate = Date() for hourOffset in 0 ..< 5 { let entryDate = Calendar.current.date(byAdding: .hour, value: hourOffset, to: currentDate)! let entry = SimpleEntry(date: entryDate, configuration: configuration) entries.append(entry) } return Timeline(entries: entries, policy: .atEnd) } // func relevances() async -> WidgetRelevances<ConfigurationAppIntent> { // // Generate a list containing the contexts this widget is relevant in. // } } struct SimpleEntry: TimelineEntry { let date: Date let configuration: ConfigurationAppIntent } struct CountdownsEntryView : View { var entry: Provider.Entry var body: some View { VStack { Text("Time:") Text(entry.date, style: .time) Text("Title:") Text(entry.configuration.countdown?.title ?? "Default") } } } struct Countdowns: Widget { let kind: String = "Countdowns" var body: some WidgetConfiguration { AppIntentConfiguration(kind: kind, intent: ConfigurationAppIntent.self, provider: Provider()) { entry in CountdownsEntryView(entry: entry) .containerBackground(.fill.tertiary, for: .widget) } } } CountdownEntity.swift, the file for the AppEntity and EntityQuery structs struct CountdownEntity: AppEntity, Identifiable { var id: UUID var title: String var date: Date var image: Data var displayRepresentation: DisplayRepresentation { DisplayRepresentation(title: "\(title)") } static var defaultQuery = CountdownQuery() static var typeDisplayRepresentation: TypeDisplayRepresentation = "Countdown" init(id: UUID, title: String, date: Date, image: Data) { self.id = id self.title = title self.date = date self.image = image } init(id: UUID, title: String, date: Date) { self.id = id self.title = title self.date = date self.image = Data() } init(countdown: CountdownEvent) { self.id = countdown.id self.title = countdown.title self.date = countdown.date self.image = countdown.image } } struct CountdownQuery: EntityQuery { typealias Entity = CountdownEntity static var typeDisplayRepresentation = TypeDisplayRepresentation(name: "Countdown Event") static var defaultQuery = CountdownQuery() @Environment(\.modelContext) private var modelContext // Warning here: Stored property '_modelContext' of 'Sendable'-conforming struct 'CountdownQuery' has non-sendable type 'Environment<ModelContext>'; this is an error in the Swift 6 language mode func entities(for identifiers: [UUID]) async throws -> [CountdownEntity] { let countdownEvents = getAllEvents(modelContext: modelContext) return countdownEvents.map { event in return CountdownEntity(id: event.id, title: event.title, date: event.date, image: event.image) } } func suggestedEntities() async throws -> [CountdownEntity] { // Return some suggested entities or an empty array return [] } } CountdownsManager.swift, this one just has the function that gets the array of countdowns func getAllEvents(modelContext: ModelContext) -> [CountdownEvent] { let descriptor = FetchDescriptor<CountdownEvent>() do { let allEvents = try modelContext.fetch(descriptor) return allEvents } catch { print("Error fetching events: \(error)") return [] } } I have installed it in my phone and when I try to edit the widget, it doesn't show me any of the elements I have created in the app, just a loading dropdown for half a second: What am I missing here?

I'm trying out putting most of my business logic in a Protocol that my @Model can conform to, but I'm running into a SwiftUI problem with a Binding that does not get magically offered up like it does when it the subview is not generic. I have a pretty basic List with a ForEach that now can't properly pass to a generic view based on a protocol. When I try to make a binding manually in the row it says that "item is immutable"... but that also doesn't help me with the NavigationLink? Which is seeing the Binding not the ? But before when the subview was concrete to Thing, it took in the and made its own Binding once it hit the view. I'm unclear on precisely where the change happens and what I can do to work around it. Before I go rearchitecting everything... is there a fix to get the NavigationLink to take on the object like before? What needs to be different? I've tried a number of crazy inits on the subview and they all seem to come back to saying either it can't figure out how to pass the type or I'm trying to use the value before it's been initialized. Have I characterized the problem correctly? Thanks! (let me know if I forgot a piece of code, but this should be the List, the Model/Protocol and the subview) import SwiftUI import SwiftData struct ThingsView: View {     @Environment(\.modelContext) var modelContext     @Query var items: [Thing]          var body: some View {         NavigationStack {             List {                 ForEach(items) { item in                     NavigationLink(value: item) {                         VStack(alignment: .leading) {                             Text(item.textInfo)                                 .font(.headline)                                                          Text(item.timestamp.formatted(date: .long, time: .shortened))                         }                     }                 }.onDelete(perform: deleteItems)             }             .navigationTitle("Fliiiing!") //PROBLEM HERE: Cannot convert value of type '(Binding<Thing>) -> EditThingableView<Thing>' to expected argument type '(Thing) -> EditThingableView<Thing>'             .navigationDestination(for: Thing.self, destination: EditThingableView<Thing>.init) #if os(macOS)             .navigationSplitViewColumnWidth(min: 180, ideal: 200) #endif             .toolbar { #if os(iOS)                 ToolbarItem(placement: .navigationBarTrailing) {                     EditButton()                                      } #endif                 ToolbarItem {                     Button(action: addItem) {                         Label("Add Item", systemImage: "plus")                     }                 }                 ToolbarItem {                     Button("Add Samples", action: addSamples)                 }             }         }     }          func addSamples() {         withAnimation {             ItemSDMC.addSamples(context: modelContext)         }     }          private func addItem() {         withAnimation {             let newItem = ItemSDMC("I did a thing!")             modelContext.insert(newItem)         }     }          func deleteItems(_ indexSet:IndexSet) {         withAnimation {             for index in indexSet {                 items[index].delete(from: modelContext)             }         }     } } #Preview {     ThingsView().modelContainer(for: ItemSDMC.self, inMemory: true) } import Foundation import SwiftData protocol Thingable:Identifiable {     var textInfo:String { get set }     var timestamp:Date { get set } } extension Thingable {     var thingDisplay:String {         "\(textInfo) with \(id) at \(timestamp.formatted(date: .long, time: .shortened))"     } } extension Thingable where Self:PersistentModel {     var thingDisplayWithID:String {         "\(textInfo) with modelID \(self.persistentModelID.id) in \(String(describing: self.persistentModelID.storeIdentifier)) at \(timestamp.formatted(date: .long, time: .shortened))"     } } struct ThingLite:Thingable, Codable, Sendable {     var textInfo: String     var timestamp: Date     var id: Int } @Model final class Thing:Thingable {     //using this default value requires writng some clean up logic looking for empty text info.     var textInfo:String = ""     //using this default value would require writing some data clean up functions looking for out of bound dates.     var timestamp:Date = Date.distantPast          init(textInfo: String, timestamp: Date) {         self.textInfo = textInfo         self.timestamp = timestamp     } } extension Thing {     var LiteThing:ThingLite {         ThingLite(textInfo: textInfo, timestamp: timestamp, id: persistentModelID.hashValue)     } } import SwiftUI struct EditThingableView<DisplayItemType:Thingable>: View {     @Binding var thingHolder: DisplayItemType          var body: some View {                  VStack {             Text(thingHolder.thingDisplay)             Form {                 TextField("text", text:$thingHolder.textInfo)                 DatePicker("Date", selection: $thingHolder.timestamp)             }                      } #if os(iOS)         .navigationTitle("Edit Item")         .navigationBarTitleDisplayMode(.inline) #endif     } } //NOTE: First sign of trouble //#Preview { //    @Previewable var myItem = Thing(textInfo: "Example Item for Preview", timestamp:Date()) //    EditThingableView<Thing>(thingHolder: myItem) //}

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?

In a document based SwiftData app for macOS, how do you go about opening a (modal) child window connected to the ModelContainer of the currently open document? Using .sheet() does not really result in a good UX, as the appearing view lacks the standard window toolbar. Using a separate WindowGroup with an argument would achieve the desired UX. However, as WindowGroup arguments need to be Hashable and Codable, there is no way to pass a ModelContainer or a ModelContext there: WindowGroup(id: "myWindowGroup", for: MyWindowGroupArguments.self) { $args in ViewThatOpensInAWindow(args: args) } Is there any other way?

Here’s the situation: • You’re downloading a huge list of data from iCloud. • You’re saving it one by one (sequentially) into SwiftData. • You don’t want the SwiftUI view to refresh until all the data is imported. • After all the import is finished, SwiftUI should show the new data. The Problem If you insert into the same ModelContext that SwiftUI’s @Environment(.modelContext) is watching, each insert may cause SwiftUI to start reloading immediately. That will make the UI feel slow, and glitchy, because SwiftUI will keep trying to re-render while you’re still importing. How to achieve this in Swift Data ?

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, I am currently developing a document-based application with additional WindowGroup for macOS and have encountered a challenge related to document container management. Specifically, I need to open a windowGroup that shares the same container as the one used in the DocumentGroup. However, my current approach of using a global shared model container has led to unintended behavior: any new document created is linked to existing ones, and changes made in one document are reflected across all documents. To address this issue, I am looking for a solution that allows each newly created document to be individualized while still sharing the document container with all relevant WindowGroups that require access to the data it holds. I would greatly appreciate any insights or recommendations you might have on how to achieve this. struct Todo: App { var body: some Scene { DocumentGroup(editing: Item.self, contentType: .item) { ContentView() } WindowGroup(for: Item.self) { $item in ItemView(item:$item) .modelContainer(Of DocumentGroup above) } } } Thank you for your time and assistance. Best regards,

Hi, I am currently developing a document-based application for macOS and have encountered a challenge related to document container management. Specifically, I need to open a windowGroup that shares the same container as the one used in the DocumentGroup. However, my current approach of using a global shared model container has led to unintended behavior: any new document created is linked to existing ones, and changes made in one document are reflected across all documents. To address this issue, I am looking for a solution that allows each newly created document to be individualized while still sharing the document container with all relevant WindowGroups that require access to the data it holds. I would greatly appreciate any insights or recommendations you might have on how to achieve this. Thank you for your time and assistance. Best regards, Something like: @main struct Todo: App { var body: some Scene { DocumentGroup(editing: Item.self, contentType: .item) { ContentView() } WindowGroup { UndockView() .modelContainer(of documentGroup above) } } }

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?

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!

I have made a Swift App for MacOS 15 under XCode 16.3, which runs fine. I also want to run it under the previous MacOS 14. Unfortunately it crashes without even starting up (it does not even reach the first log output statement on the first view) The crash reason is Crashed Thread: 0 Dispatch queue: com.apple.main-thread Exception Type: EXC_BAD_INSTRUCTION (SIGILL) Exception Codes: 0x0000000000000001, 0x0000000000000000 Termination Reason: Namespace SIGNAL, Code 4 Illegal instruction: 4 Terminating Process: exc handler [2970] I have set the miminium deployment to MacOS 14.0 but to no effect. The XCode machine is a MacOS 15.4 on Arm M3 and the target machine is MacOS 14.7.5 on Intel (MacBook Air) I think it might be related to the compiler and linker settings.

I have an issue in my app, where the crashing frame is an assertionFailure in BackingData.set inside SwiftData framework. My own app doesn't appear until frame 14. I have no idea what causes this, or even how to create a reproducible project as this only happens on some devices. The frame prior to the assertionFailure is this: #1 (null) in BackingData.set(any:value:) () It seems like there is a backing data encoding happening in my Model class, and some value is causing it to fail. The model being accessed is through a relationship, and the frame in the app crashing is along the lines of Text(parent.child.name) Obviously, something is wrong in how I have made child, but the part that stand out to me is the assertionFailure in a release build

I'm a first time developer for Swift, (getting on a bit!) but after programming in VB back in the late 90s I wanted to write an app for iPhone. I think I might have gone about it the wrong way, but I've got an app that works great on my iPhone or works great on my iPad. It saves the data persistently on device, but, no matter how much I try, what I read and even resorting to AI (ChatGPT & Gemini) I still can't get it to save the data on iCloud to synchronise between the two and work across the devices. I think it must be something pretty fundamental I'm doing (or more likely not doing) that is causing the issue. I'm setting up my signing and capabilities as per the available instructions but I always get a fatal error. I think it might be something to do with making fields optional, but at this point I'm second guessing myself and feeling a complete failure. Any advice or pointers would be really gratefully appreciated. I like my app and would like eventually to get it on the App Store but at this point in time I feel it should be on the failed projects heap! I've even tried a new Xcode project for iOS and asking it to use SwiftData and CloudKit - the default project should work - right? But it absolutely doesn't for me. Please send help!!

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:

I'm developing a medication scheduling app similar to Apple Health's Medications feature, and I'd like some input on my current approach to background tasks. In my app, when a user creates a medication, I generate ScheduledDose objects (with corresponding local notifications) for the next 2 weeks and save them to SwiftData. To ensure this 2-week window stays current, I've implemented a BGAppRefreshTask that runs daily to generate new doses as needed. My concern is whether BGAppRefreshTask is the appropriate mechanism for this purpose. Since I'm not making any network requests but rather generating and storing local data, I'm questioning if this is the right approach. I'm also wondering how Apple Health's Medications feature handles this kind of scheduling. Their app seems to maintain future doses regardless of app usage patterns. Has anyone implemented something similar or can suggest the best background execution API for this type of scenario? Thanks for any guidance you can provide.

I’m trying to build a CRUD app using SwiftData, @Query model and multidatepicker. The data from a multidatepicker is stored or persists in SwiftData as Set = []. My current dilemma is how to use SwiftData and @Query model Predicate to find all records on the current date. I can’t find any SwiftData documentation or examples @Query using Set = []. My CRUD app should retrieve all records for the current date. Unfortunately, I don’t know the correct @Query model syntax for Set = [].

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

Context: The SwiftUI @Query macro has an internal modelContext. The ModelActor also has a modelContext, from which the data should be read/written. Issue: When writing to @Model data fetched with @Query macro using a ModelActor, it will crash in the most not-obvious ways. Also, fetching @Model with ModelActor will result in errors in Swift 6 since @Model aren't sendable. Problem to Solve: - How to write a good amount of data to SwiftData/CoreData without blocking the UI thread? Would the recommendation from the Apple team be that a large amount of data should be read/written with ModelActor and a small amount should be done with the @Query's internal modelContext ?

The following complex migration consistently crashes the app with the following error: SwiftData/PersistentModel.swift:726: Fatal error: What kind of backing data is this? SwiftData._KKMDBackingData<SwiftDataMigration.ItemSchemaV1.ItemList> My app relies on a complex migration that involves these optional 1 to n relationships. Theoretically I could not assign the relationships in the willMigrate block but afterwards I am not able to tell which list and items belonged together. Steps to reproduce: Run project Change typealias CurrentSchema to ItemSchemaV2 instead of ItemSchemaV1. Run project again -> App crashes My setup: Xcode Version 16.2 (16C5032a) MacOS Sequoia 15.4 iPhone 12 with 18.3.2 (22D82) Am I doing something wrong or did I stumble upon a bug? I have a demo Xcode project ready but I could not upload it here so I put the code below. Thanks for your help typealias CurrentSchema = ItemSchemaV1 typealias ItemList = CurrentSchema.ItemList typealias Item = CurrentSchema.Item @main struct SwiftDataMigrationApp: App { var sharedModelContainer: ModelContainer = { do { return try ModelContainer(for: ItemList.self, migrationPlan: MigrationPlan.self) } catch { fatalError("Could not create ModelContainer: \(error)") } }() var body: some Scene { WindowGroup { ContentView() } .modelContainer(sharedModelContainer) } } This is the migration plan enum MigrationPlan: SchemaMigrationPlan { static var schemas: [any VersionedSchema.Type] { [ItemSchemaV1.self, ItemSchemaV2.self] } static var stages: [MigrationStage] = [ MigrationStage.custom(fromVersion: ItemSchemaV1.self, toVersion: ItemSchemaV2.self, willMigrate: { context in print("Started migration") let oldlistItems = try context.fetch(FetchDescriptor<ItemSchemaV1.ItemList>()) for list in oldlistItems { let items = list.items.map { ItemSchemaV2.Item(timestamp: $0.timestamp)} let newList = ItemSchemaV2.ItemList(items: items, name: list.name, note: "This is a new property") context.insert(newList) context.delete(list) } try context.save() // Crash indicated here print("Finished willMigrate") }, didMigrate: { context in print("Did migrate successfully") }) ] } The versioned schemas enum ItemSchemaV1: VersionedSchema { static var versionIdentifier = Schema.Version(1, 0, 0) static var models: [any PersistentModel.Type] { [Item.self] } @Model final class Item { var timestamp: Date var list: ItemSchemaV1.ItemList? init(timestamp: Date) { self.timestamp = timestamp } } @Model final class ItemList { @Relationship(deleteRule: .cascade, inverse: \ItemSchemaV1.Item.list) var items: [Item] var name: String init(items: [Item], name: String) { self.items = items self.name = name } } } enum ItemSchemaV2: VersionedSchema { static var versionIdentifier = Schema.Version(2, 0, 0) static var models: [any PersistentModel.Type] { [Item.self] } @Model final class Item { var timestamp: Date var list: ItemSchemaV2.ItemList? init(timestamp: Date) { self.timestamp = timestamp } } @Model final class ItemList { @Relationship(deleteRule: .cascade, inverse: \ItemSchemaV2.Item.list) var items: [Item] var name: String var note: String init(items: [Item], name: String, note: String = "") { self.items = items self.name = name self.note = note } } } Last the ContentView: struct ContentView: View { @Query private var itemLists: [ItemList] var body: some View { NavigationSplitView { List { ForEach(itemLists) { list in NavigationLink { List(list.items) { item in Text(item.timestamp.formatted(date: .abbreviated, time: .complete)) } .navigationTitle(list.name) } label: { Text(list.name) } } } .navigationTitle("Crashing migration demo") .onAppear { if itemLists.isEmpty { for index in 0..<10 { let items = [Item(timestamp: Date.now)] let listItem = ItemList(items: items, name: "List No. \(index)") modelContext.insert(listItem) } try! modelContext.save() } } } detail: { Text("Select an item") } } }