I'm testing my app before releasing to testers, and my app (both macOS and iOS) is crashing when I perform one operation, but only in the production build. I have data that loads from a remote source, and can be periodically updated. There is an option to delete all of that data from the iCloud data store, unless the user has modified a record. Each table has a flag to indicate that (userEdited). Here's the function that is crashing: func deleteCommonData<T:PersistentModel & SDBuddyModel>(_ type: T.Type) throws { try modelContext.delete(model: T.self, where: #Predicate<T> { !$0.userEdited }) } Here's one of the calls that results in a crash: try modelManager.deleteCommonData(Link.self) Here's the error from iOS Console: SwiftData/DataUtilities.swift:85: Fatal error: Couldn't find \Link.<computed 0x0000000104b9d208 (Bool)> on Link with fields [SwiftData.Schema.PropertyMetadata(name: "id", keypath: \Link.<computed 0x0000000104b09b44 (String)>, defaultValue: Optional("54EC6602-CA7C-4EC7-AC06-16E7F2E22DE7"), metadata: nil), SwiftData.Schema.PropertyMetadata(name: "name", keypath: \Link.<computed 0x0000000104b09b84 (String)>, defaultValue: Optional(""), metadata: nil), SwiftData.Schema.PropertyMetadata(name: "url", keypath: \Link.<computed 0x0000000104b09bc4 (String)>, defaultValue: Optional(""), metadata: nil), SwiftData.Schema.PropertyMetadata(name: "desc", keypath: \Link.<computed 0x0000000104b09c04 (String)>, defaultValue: Optional(""), metadata: nil), SwiftData.Schema.PropertyMetadata(name: "userEdited", keypath: \Link.<computed 0x0000000104b09664 (Bool)>, defaultValue: Optional(false), metadata: nil), SwiftData.Schema.PropertyMetadata(name: "modified", keypath: \Link.<computed 0x0000000104b09c44 (Date)>, defaultVal<…> Here's a fragment of the crash log: Exception Type: EXC_BREAKPOINT (SIGTRAP) Exception Codes: 0x0000000000000001, 0x000000019373222c Termination Reason: Namespace SIGNAL, Code 5, Trace/BPT trap: 5 Terminating Process: exc handler [80543] Thread 0 Crashed: 0 libswiftCore.dylib 0x19373222c _assertionFailure(_:_:file:line:flags:) + 176 1 SwiftData 0x22a222160 0x22a1ad000 + 479584 2 SwiftData 0x22a2709c0 0x22a1ad000 + 801216 3 SwiftData 0x22a221b08 0x22a1ad000 + 477960 4 SwiftData 0x22a27b0ec 0x22a1ad000 + 844012 5 SwiftData 0x22a27b084 0x22a1ad000 + 843908 6 SwiftData 0x22a28182c 0x22a1ad000 + 870444 7 SwiftData 0x22a2809e8 0x22a1ad000 + 866792 8 SwiftData 0x22a285204 0x22a1ad000 + 885252 9 SwiftData 0x22a281c7c 0x22a1ad000 + 871548 10 SwiftData 0x22a27cf6c 0x22a1ad000 + 851820 11 SwiftData 0x22a27cc48 0x22a1ad000 + 851016 12 SwiftData 0x22a27a6b0 0x22a1ad000 + 841392 13 SwiftData 0x22a285b2c 0x22a1ad000 + 887596 14 SwiftData 0x22a285a10 0x22a1ad000 + 887312 15 SwiftData 0x22a285bcc 0x22a1ad000 + 887756 16 SwiftData 0x22a27cf6c 0x22a1ad000 + 851820 17 SwiftData 0x22a27cc48 0x22a1ad000 + 851016 18 SwiftData 0x22a27a6b0 0x22a1ad000 + 841392 19 SwiftData 0x22a27c0d8 0x22a1ad000 + 848088 20 SwiftData 0x22a27a654 0x22a1ad000 + 841300 21 SwiftData 0x22a1be548 0x22a1ad000 + 70984 22 SwiftData 0x22a1cfd64 0x22a1ad000 + 142692 23 SwiftData 0x22a1b9618 0x22a1ad000 + 50712 24 SwiftData 0x22a1d2e8c 0x22a1ad000 + 155276 25 CoreData 0x187fbb568 thunk for @callee_guaranteed () -> (@out A, @error @owned Error) + 28 26 CoreData 0x187fc2300 partial apply for thunk for @callee_guaranteed () -> (@out A, @error @owned Error) + 24 27 CoreData 0x187fc19c4 closure #1 in closure #1 in NSManagedObjectContext._rethrowsHelper_performAndWait<A>(fn:execute:rescue:) + 192 28 CoreData 0x187fbbda8 thunk for @callee_guaranteed @Sendable () -> () + 28 29 CoreData 0x187fbbdd0 thunk for @escaping @callee_guaranteed @Sendable () -> () + 28 30 CoreData 0x187f663fc developerSubmittedBlockToNSManagedObjectContextPerform + 252 31 libdispatch.dylib 0x180336ac4 _dispatch_client_callout + 16 32 libdispatch.dylib 0x18032c940 _dispatch_lane_barrier_sync_invoke_and_complete + 56 33 CoreData 0x187fd7290 -[NSManagedObjectContext performBlockAndWait:] + 364 34 CoreData 0x187fc1fb8 NSManagedObjectContext.performAndWait<A>(_:) + 544 35 SwiftData 0x22a1b877c 0x22a1ad000 + 46972 36 SwiftData 0x22a1be2a8 0x22a1ad000 + 70312 37 SwiftData 0x22a1c0e34 0x22a1ad000 + 81460 38 SwiftData 0x22a23ea94 0x22a1ad000 + 596628 39 SwiftData 0x22a256828 0x22a1ad000 + 694312 40 Sourdough Buddy 0x104e5dc98 specialized ModelManager.deleteCommonData<A>(_:) + 144 (ModelManager.swift:128) [inlined] 41 Sourdough Buddy 0x104e5dc98 closure #1 in SettingsView.clearStarterData.getter + 876 (SettingsView.swift:243) It works if I do the following instead: try modelContext.delete(model: Link.self, where: #Predicate { !$0.userEdited }) Why would the func call work in development, but crash in production? And why does doing the more verbose way work instead? I think this is a bug. Thanks

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.

First the model: import SwiftData //Model one: type of contract, i.e. Firm Fixed Price, etc @Model final class TypeOfContract { var contracts: [Contract] @Attribute(.unique) var typeName: String @Attribute(.unique) var typeCode: String var typeDescription: String init(contracts: [Contract], typeName: String = "", typeCode: String = "", typeDescription: String = "") { self.contracts = contracts self.typeName = typeName self.typeCode = typeCode self.typeDescription = typeDescription } } //Model two: the Contract @Model final class Contract { var contractType: TypeOfContract? var costReports: [CostReport] @Attribute(.unique) var contractNumber: String @Attribute(.unique) var contractName: String var startDate: Date var endDate: Date var contractValue: Decimal var contractCompany: String var contractContact: String var contactEmail: String var contactPhone: String var contractNotes: String init(contractType: TypeOfContract?, costReports: [CostReport], contractNumber: String = "", contractName: String = "", startDate: Date = .now, endDate: Date = .now, contractValue: Decimal = 0.00, contractCompany: String = "", contractContact: String = "", contactEmail: String = "", contactPhone: String = "", contractNotes: String = "") { self.contractType = contractType self.costReports = costReports self.contractNumber = contractNumber self.contractName = contractName self.startDate = startDate self.endDate = endDate self.contractValue = contractValue self.contractCompany = contractCompany self.contractContact = contractContact self.contactEmail = contactEmail self.contactPhone = contactPhone self.contractNotes = contractNotes } } //Model Three: The Cost Reports @Model final class CostReport { var contract: Contract? var periodStartDate: Date var periodEndDate: Date var bCWP: Double //Budgeted Cost Work Performed var aCWP: Double //Actual Cost Work Performed var bCWS: Double //Budgeted Cost Work Scheduled //Calculated fields init(contract: Contract?, periodStartDate: Date = .now, periodEndDate: Date = .now, bCWP: Double = 0.0, aCWP: Double = 0.0, bCWS: Double = 0.0) { self.contract = contract self.periodStartDate = periodStartDate self.periodEndDate = periodEndDate self.bCWP = bCWP self.aCWP = aCWP self.bCWS = bCWS } } Now the code for the Picker ```import SwiftUI import SwiftData struct EnterNewContract: View { @Environment(\.modelContext) var modelContext @Query(sort: \TypeOfContract.typeName) private var typeOfContracts: [TypeOfContract] @Query private var contracts: [Contract] @State private var costReports: [CostReport] = [] @State private var contractType: [TypeOfContract]? @State private var contractNumber: String = "" @State private var contractName: String = "" @State private var startDate: Date = Date() @State private var endDate: Date = Date() @State private var contractValue: Decimal = 0 @State private var contractCompany: String = "" @State private var contractContact: String = "" @State private var contactEmail: String = "" @State private var contactPhone: String = "" @State private var contractNotes: String = "" var body: some View { Form { VStack { Section(header: Text("Enter New Contract") .foregroundStyle(.green) .font(.headline)){ Picker("Select a type of contract", selection: $contractType) {Text("Select type").tag(nil as TypeOfContract?) ForEach(typeOfContracts, id: \.self) { typeOfContracts in Text(typeOfContracts.typeName) .tag(typeOfContracts as TypeOfContract?) } } TextField("Contract Number", text: $contractNumber) .frame(width: 800, height: 40) TextField("Contract Name", text: $contractName) .frame(width: 800, height: 40) DatePicker("Contract Start Date", selection: $startDate, displayedComponents: [.date]) DatePicker("Contract End Date", selection: $endDate, displayedComponents: [.date]) } } } } } The code works, for the most part. The selection I make from the list does not appear. Instead there is just a shaded empty box . Also, I need to select my selection choice twice before the check mark to appear. To see the choices and my selection I must click on the empty shaded box. What did I do wrong

Have a data model that sets certain fields as unique. If the user attempts to save a duplicate value, the save fails quietly with no indication to the user that the save failed. The program is on Mac OS 26.0.1 @Environment(\.modelContext) var modelContext @Query private var typeOfContracts: [TypeOfContract] @State private var typeName: String = "" @State private var typeCode: String = "" @State private var typeDescription: String = "" @State private var contracts: [Contract] = [] @State private var errorMessage: String? = "Data Entered" @State private var showAlert: Bool = false var body: some View { Form { Text("Enter New Contract Type") .font(.largeTitle) .foregroundStyle(Color(.green)) .multilineTextAlignment(.center) TextField("Contract Type Name", text: $typeName) .frame(width: 800, height: 40) TextField("Contract Type Code", text: $typeCode) .frame(width: 800, height: 40) Text("Contract Type Description") TextEditor(text: $typeDescription) .frame(width: 800, height: 200) .scrollContentBackground(.hidden) .background(Color.teal) .font(.system(size: 24)) Button(action: { self.saveContractType() }) { Text("Save new contract type") } } } func saveContractType() { let typeOfContract = TypeOfContract(contracts: []) typeOfContract.typeName = typeName typeOfContract.typeCode = typeCode typeOfContract.typeDescription = typeDescription modelContext.insert(typeOfContract) do { try modelContext.save() }catch { errorMessage = "Error saving data: \(error.localizedDescription)" } } } I have tried to set alerts but Xcode tells me that the alerts are not in scope

I am attempting to impliment a a Picker that uses SwiftData to fill in the choices. I am missing something because I can get the picker to appear with the proper selections but the picker does not register my choice (no check mark appears and the text in the picker window is blank after I move to the next field. The model import Foundation import SwiftData //Model one: type of contract, i.e. Firm Fixed Price, etc @Model final class TypeOfContract { var contracts: [Contract] @Attribute(.unique) var typeName: String @Attribute(.unique) var typeCode: String var typeDescription: String init(contracts: [Contract], typeName: String = "", typeCode: String = "", typeDescription: String = "") { self.contracts = contracts self.typeName = typeName self.typeCode = typeCode self.typeDescription = typeDescription } } //Model two: the Contract @Model final class Contract { var contractType: TypeOfContract? var costReports: [CostReport] @Attribute(.unique) var contractNumber: String @Attribute(.unique) var contractName: String var startDate: Date var endDate: Date var contractValue: Decimal var contractCompany: String var contractContact: String var contactEmail: String var contactPhone: String var contractNotes: String init(contractType: TypeOfContract? = nil, costReports: [CostReport], contractNumber: String = "", contractName: String = "", startDate: Date = .now, endDate: Date = .now, contractValue: Decimal = 0.00, contractCompany: String = "", contractContact: String = "", contactEmail: String = "", contactPhone: String = "", contractNotes: String = "") { self.contractType = contractType self.costReports = costReports self.contractNumber = contractNumber self.contractName = contractName self.startDate = startDate self.endDate = endDate self.contractValue = contractValue self.contractCompany = contractCompany self.contractContact = contractContact self.contactEmail = contactEmail self.contactPhone = contactPhone self.contractNotes = contractNotes } } //Model Three: The Cost Reports @Model final class CostReport { var contract: Contract? var periodStartDate: Date var periodEndDate: Date var bCWP: Double //Budgeted Cost Work Performed var aCWP: Double //Actual Cost Work Performed var bCWS: Double //Budgeted Cost Work Scheduled //Calculated fields init(contract: Contract? = nil, periodStartDate: Date = .now, periodEndDate: Date = .now, bCWP: Double = 0.0, aCWP: Double = 0.0, bCWS: Double = 0.0) { self.contract = contract self.periodStartDate = periodStartDate self.periodEndDate = periodEndDate self.bCWP = bCWP self.aCWP = aCWP self.bCWS = bCWS } } The Swift Code for the input form import SwiftData struct EnterNewContract: View { @Environment(\.modelContext) var modelContext @Query(sort: \TypeOfContract.typeCode) private var typeOfContracts: [TypeOfContract] @Query private var contracts: [Contract] @State private var costReports: [CostReport] = [] @State private var contractType: [TypeOfContract] = [] @State private var contractNumber: String = "" @State private var contractName: String = "" @State private var startDate: Date = Date() @State private var endDate: Date = Date() @State private var contractValue: Decimal = 0 @State private var contractCompany: String = "" @State private var contractContact: String = "" @State private var contactEmail: String = "" @State private var contactPhone: String = "" @State private var contractNotes: String = "" var body: some View { Form { VStack { Section(header: Text("Enter New Contract") .foregroundStyle(.green) .font(.headline)){ Picker("Select a type of contract", selection: $contractType) { ForEach(typeOfContracts, id: \.self) { typeOfContracts in Text(typeOfContracts.typeCode) .tag(contractType) } } TextField("Contract Number", text: $contractNumber) .frame(width: 800, height: 40) TextField("Contract Name", text: $contractName) .frame(width: 800, height: 40) DatePicker("Contract Start Date", selection: $startDate, displayedComponents: [.date]) DatePicker("Contract End Date", selection: $endDate, displayedComponents: [.date]) } } } } }

Hi, Not sure how to describe my issue best: I am using SwiftData and CloudKit to store my data. In the past, when I tested my app on different devices, the data would sync between the devices automatically. For whatever reason this has stopped now and the data no longer syncs. No matter what I do, it feels as if all the data is actually stored just locally on each device. How can I check if the data is actually stored in the cloud and what could be reasons, why its no longer synching between my devices (and yes, I am logged in with the same Apple ID on all devices). Thanks for any hint! Max

When deleting a SwiftData entity, I sometimes encounter the following error in a document based SwiftUI app: Fatal error: Unexpected backing data for snapshot creation: SwiftData._FullFutureBackingData<MyEntityClass> The deletion happens in a SwiftUI View and the code used to retrieve the entity is standard (the ModelContext is injected from the @Environment): let myEntity = modelContext.model(for: entityIdToDelete) modelContext.delete(myEntity) Unfortunately, I haven't yet managed to isolate this any further in order to come up with a reproducible PoC. Could you give me further information about what this error means?

I have an app with SwiftData and CloudKit sync enabled, it was working fine but I recently noticed that the sync with CloudKit is not working anymore. All the changes are persisted locally just fine. When running in simulator (iOS 26/iPhone 17 Pro) I get the following error in the console: CoreData+CloudKit: -[NSCloudKitMirroringDelegate recoverFromError:](2317): <NSCloudKitMirroringDelegate: 0x600003d14c30> - Attempting recovery from error: Error Domain=NSCocoaErrorDomain Code=134421 "Export encountered an unhandled exception while analyzing history in the store." UserInfo={NSLocalizedFailureReason=Export encountered an unhandled exception while analyzing history in the store., NSUnderlyingException=-[NSEntityDescription objectID]: unrecognized selector sent to instance 0x60000351aec0} I already tried Reseting the environment back to production in CloudKit and Erasing all Contents and Settings in the simulator but I keep getting the same error. Is there something else I can do to fix this?

Hello Apple Developer Forum, I got the following statement from the AI model. It seems it is also reflecting my real-world experience. Where do I find an official source that fully describes the array on swiftData model behaviour? When a SwiftData model contains an array of value types, such as [String] or [Int], the array's order is preserved

I have an app that uses a Share Extension that allows the user to share videos, from Files and Photos etc., the video URL and some related data is then persisted with SwiftData and synchronized with CloudKit. This code has worked consistently for a long time although recently, with iOS 26 and recent builds of iOS 18, I have observed that the video is either not saved to SwiftData (iOS 26.0), or available locally when the app is opened on the same device where the share occurred, but not synchronized to other devices (iOS 18.7 and iOS 26.1 beta). Assuming the video is opened locally after being shared into the app, it is typically synchronized with CloudKit to other devices although it's not as reliable as it should be. Is there a reliable approach in the Share Extension to ensure that the data is saved to the local SwiftData database and then synchronized with CloudKit. I suspect it could be that the lifetime of the Share Extension has become even more constrained in recent OS updates that the process ends before it has the opportunity to save and synchronize the data. Any thoughts on how to ensure this is reliable would be greatly appreciated. The data saved is not too large as it consists only of the video URL and not the data of the video itself.

Hi, I did cloudkit synchronization using swiftdata. However, synchronization does not occur automatically, and synchronization occurs intermittently only when the device is closed and opened. For confirmation, after changing the data in Device 1 (saving), when the data is fetched from Device 2, there is no change. I've heard that there's still an issue with swiftdata sync and Apple is currently troubleshooting it, is the phenomenon I'm experiencing in the current version normal?

I'm trying to set up an application using SwiftData to have a number of models backed by a local datastore that's not synced to CloudKit, and another set of models that is. I was able to achieve this previously with Core Data using multiple NSPersistentStoreDescription instances. The set up code looks something like: do { let fullSchema = Schema([ UnsyncedModel.self, SyncedModel.self, ]) let localSchema = Schema([UnsyncedModel.self]) let localConfig = ModelConfiguration(schema: localSchema, cloudKitDatabase: .none) let remoteSchema = Schema([SyncedModel.self]) let remoteConfig = ModelConfiguration(schema: remoteSchema, cloudKitDatabase: .automatic) container = try ModelContainer(for: fullSchema, configurations: localConfig, remoteConfig) } catch { fatalError("Failed to configure SwiftData container.") } However, it doesn't seem to work as expected. If I remove the synced/remote schema and configuration then everything works fine, but the moment I add in the remote schema and configuration I get various different application crashes. Some examples below: A Core Data error occurred." UserInfo={Reason=Entity named:... not found for relationship named:..., Fatal error: Failed to identify a store that can hold instances of SwiftData._KKMDBackingData<...> Has anyone ever been able to get a similar setup to work using SwiftData?

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,

I'm experiencing a significant UI freeze in my SwiftUI app that uses SwiftData with CloudKit sync. When users tap a button to present a sheet for the first time after app launch, the entire UI becomes unresponsive for 5-10 seconds. Subsequent sheet presentations work fine. App Architecture Service layer: An @Observable class marked with @MainActor that orchestrates operations Persistence layer: A @ModelActor class that handles SwiftData operations SwiftUI views: Using @Environment to access the service layer The structure looks like this: @Observable @MainActor final class MyServices { let persistence: DataPersistence init(modelContainer: ModelContainer) { self.persistence = DataPersistence(modelContainer: modelContainer) } func addItem(title: String) async { // Creates and saves an item through persistence layer } } @ModelActor actor DataPersistence { func saveItem(_ item: Item) async { // Save to SwiftData } } The app initializes the ModelContainer at the Scene level and passes it through the environment: @main struct MyApp: App { let container = ModelContainer(for: Item.self) var body: some Scene { WindowGroup { ContentView() .modelContainer(container) .environment(MyServices(modelContainer: container)) } } } The Problem When a user taps the "Add Item" button which presents a sheet: Button("Add Item") { showingAddSheet = true } .sheet(isPresented: $showingAddSheet) { AddItemView(onAdd: { title in await services.addItem(title: title) }) } The UI freezes completely for 5-10 seconds on first presentation. During this time: The button remains in pressed state No UI interactions work The app appears completely frozen After the freeze, the sheet opens and everything works normally This only happens on the first sheet presentation after app launch. I suspect it's related to SwiftData's ModelContext initialization happening on the main thread despite using @ModelActor, but I'm not sure why this would happen given that ModelActor should handle background execution. Environment iOS 18 SwiftData with CloudKit sync enabled Xcode 16 Swift 6 Has anyone experienced similar freezes with SwiftData and @ModelActor? Is there something wrong with how I'm structuring the initialization of these components? The documentation suggests @ModelActor should handle background operations automatically, but the freeze suggests otherwise. Any insights would be greatly appreciated!

I'm developing an app that uses CloudKit synchronization with SwiftData and on visionOS I added an App Settings bundle. I have noticed that sometimes, when the app is open and the user changes a setting from the App Settings bundle, the following fatal error occurs: SwiftData/BackingData.swift:831: Fatal error: This model instance was destroyed by calling ModelContext.reset and is no longer usable. The setting is read within the App struct in the visionOS app target using @AppStorage and this value is in turn used to set the passthrough video dimming via the .preferredSurroundingsEffect modifier. The setting allows the user to specify the dimming level as dark, semi dark, or ultra dark. The fatal error appears to occur intermittently although the first time it was observed was after adding the settings bundle. As such, I suspect there is some connection between those code changes and this fatal error even though they do not directly relate to SwiftData.

How does SwiftData work with background operations? CoreData had background context that could be used to avoid UI hang for heavy operations. Is there an equivalent in SwiftData, and if so, do I have to merge changes or does it save directly to persistent store?

Hi all, As you know, when using SwiftData Cloudkit, all relationships are required to be optional. In my app, which is a list app, I have a model class Project that contains an array of Subproject model objects. A Subproject also contains an array of another type of model class and this chain goes on and on. In this type of pattern, it becomes really taxxing to handle the optionals the correct way, i.e. unwrap them as late as possible and display an error to the user if unable to. It seems like most developers don't even bother, they just wrap the array in a computed property that returns an empty array if nil. I'm just wondering what is the recommended way by Apple to handle these optionals. I'm not really familiar with how the CloudKit backend works, but if you have a simple list app that only saves to the users private iCloud, can I just handwave the optionals like so many do? Is it only big data apps that need to worry? Or should we always strive to handle them the correct way? If that's the case, why does it seem like most people skip over them? Be great if an Apple engineer could weigh in.

Every time I insert a subclass (MYShapeLayer) into the model context, the app crashes with an error: DesignerPlayground crashed due to fatalError in BackingData.swift at line 908. Never access a full future backing data - PersistentIdentifier(id: SwiftData.PersistentIdentifier.ID(backing: SwiftData.PersistentIdentifier.PersistentIdentifierBacking.managedObjectID(0xb2dbc55f3f4c57f2 <x-coredata://B1E3206B-40DE-4185-BC65-4540B4705B40/MYShapeLayer/p1>))) with Optional(A6CA4F89-107F-4A66-BC49-DD7DAC689F77) struct ContentView: View { @Environment(\.modelContext) private var modelContext @Query private var designs: [MYDesign] var layers: [MYLayer] { designs.first?.layers ?? [] } var body: some View { NavigationStack { List { ForEach(layers) { layer in Text(layer.description) } } .onAppear { let design = MYDesign(title: "My Design") modelContext.insert(design) try? modelContext.save() } .toolbar { Menu("Add", systemImage: "plus") { Button(action: addTextLayer) { Text("Add Text Layer") } Button(action: addShapeLayer) { Text("Add Shape Layer") } } } } } private func addTextLayer() { if let design = designs.first { let newLayer = MYLayer(order: layers.count, kind: .text) newLayer.design = design modelContext.insert(newLayer) try? modelContext.save() } } private func addShapeLayer() { if let design = designs.first { let newLayer = MYShapeLayer(shapeName: "Ellipse", order: layers.count) newLayer.design = design modelContext.insert(newLayer) try? modelContext.save() } } } #Preview { ContentView() .modelContainer(for: [MYDesign.self, MYLayer.self, MYShapeLayer.self], inMemory: true) } @Model final class MYDesign { var title: String = "" @Relationship(deleteRule: .cascade, inverse: \MYLayer.design) var layers: [MYLayer] = [] init(title: String = "") { self.title = title } } @available(iOS 26.0, macOS 26.0, *) @Model class MYLayer { var design: MYDesign! var order: Int = 0 var title: String = "" init(order: Int = 0, title: String = "New Layer") { self.order = order self.title = title } } @available(iOS 26.0, macOS 26.0, *) @Model class MYShapeLayer: MYLayer { var shapeName: String = "" init(shapeName: String, order: Int = 0) { self.shapeName = shapeName super.init(order: order) } }

I have a simple app that makes an HTTPS call to gather some JSON which I then parse and add to my SwiftData database. The app then uses a simple @Query in a view to get the data into a list. on iOS 16 this works fine. No problems. But the same code on iOS 26 (targeting iOS 18.5) crashes after about 15 seconds of idle time after the list is populated. The error message is: Could not cast value of type '__NSCFNumber' (0x1f31ee568) to 'NSString' (0x1f31ec718). and occurs when trying to access ANY property of the list. I have a stripped down version of the app that shows the crash available. To replicate the issue: open the project in Xcode 26 target any iOS 26 device or simulator compile and run the project. after the list is displayed, wait about 15 seconds and the app crashes. It is also of note that if you try to run the app again, it will crash immediately, unless you delete the app from the device. Any help on this would be appreciated. Feedback number FB20295815 includes .zip file Below is the basic code (without the data models) The Best Seller List.Swift import SwiftUI import SwiftData @main struct Best_Seller_ListApp: App { var body: some Scene { WindowGroup { ContentView() } .modelContainer (for: NYTOverviewResponse.self) } } ContentView.Swift import os.log import SwiftUI struct ContentView: View { @Environment(\.modelContext) var modelContext @State private var listEncodedName = String() var body: some View { NavigationStack () { ListsView() } .task { await getBestSellerLists() } } func getBestSellerLists() async { guard let url = URL(string: "https://api.nytimes.com/svc/books/v3/lists/overview.json?api-key=\(NYT_API_KEY)") else { Logger.errorLog.error("Invalid URL") return } do { let decoder = JSONDecoder() var decodedResponse = NYTOverviewResponse() //decode the JSON let (data, _) = try await URLSession.shared.data(from: url) decoder.keyDecodingStrategy = .convertFromSnakeCase decodedResponse = try decoder.decode(NYTOverviewResponse.self, from: data) //remove any lists that don't have list_name_encoded. Fixes a bug in the data decodedResponse.results!.lists = decodedResponse.results!.lists!.filter { $0.listNameEncoded != "" } // sort the lists decodedResponse.results!.lists!.sort { (lhs, rhs) -> Bool in lhs.displayName < rhs.displayName } //delete any potential existing data try modelContext.delete(model: NYTOverviewResponse.self) //add the new data modelContext.insert(decodedResponse) } catch { Logger.errorLog.error("\(error.localizedDescription)") } } } ListsView.Swift import os.log import SwiftData import SwiftUI @MainActor struct ListsView: View { //MARK: - Variables and Constants @Query var nytOverviewResponses: [NYTOverviewResponse] enum Updated: String { case weekly = "WEEKLY" case monthly = "MONTHLY" } //MARK: - Main View var body: some View { List { if nytOverviewResponses.isEmpty { ContentUnavailableView("No lists yet", systemImage: "list.bullet", description: Text("NYT Bestseller lists not downloaded yet")) } else { WeeklySection MonthlySection } } .navigationBarTitle("Bestseller Lists", displayMode: .large) .listStyle(.grouped) } var WeeklySection: some View { let rawLists = nytOverviewResponses.last?.results?.lists ?? [] // Build a value-typed array to avoid SwiftData faulting during sort let weekly = rawLists .filter { $0.updateFrequency == Updated.weekly.rawValue } .map { (name: $0.displayName, encoded: $0.listNameEncoded, model: $0) } .sorted { $0.name < $1.name } return Section(header: Text("Weekly lists to be published on \(nytOverviewResponses.last?.results?.publishedDate ?? "-")")) { ForEach(weekly, id: \.encoded) { item in Text(item.name).font(Font.custom("Georgia", size: 17)) } } } var MonthlySection: some View { let rawLists = nytOverviewResponses.last?.results?.lists ?? [] // Build a value-typed array to avoid SwiftData faulting during sort let monthly = rawLists .filter { $0.updateFrequency == Updated.monthly.rawValue } .map { (name: $0.displayName, encoded: $0.listNameEncoded, model: $0) } .sorted { $0.name < $1.name } return Section(header: Text("Monthly lists to be published on \(nytOverviewResponses.last?.results?.publishedDate ?? "-")")) { ForEach(monthly, id: \.encoded) { item in Text(item.name).font(Font.custom("Georgia", size: 17)) } } } }

The 'unique' attribute is a really nice feature, BUT. In some of my apps, the unique identifier for an object is a combination of multiple attributes. (Example: a book title is not unique, but a combination of book title and author list is.) How do I model this with SwiftData? I cannot use @Attribute(.unique) on either the title OR the author list, but I want SwiftData to provide the same "insert or update" logic. Is this possible?