Hi. I'm hoping someone might be able to help us with an issue that's been affecting our standalone watchOS app for some time now.
We've encountered consistent crashes on Apple Watch devices when the app enters the background while the device is offline (i.e., no Bluetooth and no Wi-Fi connection). Through extensive testing, we've isolated the problem to the use of NSPersistentCloudKitContainer. When we switch to NSPersistentContainer, the crashes no longer occur.
Interestingly, this issue only affects our watchOS app. The same CloudKit-based persistence setup works reliably on our iOS and macOS apps, even when offline. This leads us to believe the issue may be specific to how NSPersistentCloudKitContainer behaves on watchOS when the device is disconnected from the network.
We're targeting watchOS 10 and above. We're unsure if this is a misconfiguration on our end or a potential system-level issue, and we would greatly appreciate any insight or guidance.
iCloud & Data
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I have the following struct doing some simple tasks, running a network request and then saving items to Core Data.
Per Xcode 26's new default settings (onisolated(nonsending) & defaultIsolation set to MainActor), the struct and its functions run on the main actor, which works fine and I can even safely omit the context.perform call because of it, which is great.
struct DataHandler {
func importGames(withIDs ids: [Int]) async throws {
...
let context = PersistenceController.shared.container.viewContext
for game in games {
let newGame = GYGame(context: context)
newGame.id = UUID()
}
try context.save()
}
}
Now, I want to run this in a background thread to increase performance and responsiveness. So I followed this session (https://developer.apple.com/videos/play/wwdc2025/270) and believe the solution is to mark the struct as nonisolated and the function itself as @concurrent.
The function now works on a background thread, but I receive a crash: _dispatch_assert_queue_fail. This happens whether I wrap the Core Data calls with context.perform or not. Alongside that I get a few new warnings which I have no idea how to work around.
So, what am I doing wrong here? What's the correct way to solve this simple use case with Swift 6's new concurrency stuff and the default main actor isolation in Xcode 26?
Curiously enough, when setting onisolated(nonsending) to false & defaultIsolation to non isolating, mimicking the previous behavior, the function works without crashing.
nonisolated
struct DataHandler {
@concurrent
func importGames(withIDs ids: [Int]) async throws {
...
let context = await PersistenceController.shared.container.newBackgroundContext()
for game in games {
let newGame = GYGame(context: context)
newGame.id = UUID() // Main actor-isolated property 'id' can not be mutated from a nonisolated context; this is an error in the Swift 6 language mode
}
try context.save()
}
}
Hello,
My app has had CloudKit enabled for a while, but it's not working. I get the error "Invalid bundle ID for container".
Configure CloudKit in your project from TN3164 suggests changing to a new container. I tried changing to a new container, but this leads to data loss.
The article recommends:
"If your CloudKit container is already used in the production environment and switching to a new container leads to data loss, consider filing a feedback report with the following information to request manually associating your CloudKit container with your app ID."
Where can I request this manual association? Is there anything else I can do?
Thank you for your time and assistance. I’d appreciate a prompt resolution, as this issue is blocking our update. Looking forward to guidance.
I am trying out the new AttributedString binding with SwiftUI’s TextEditor in iOS26. I need to save this to a Core Data database. Core Data has no AttributedString type, so I set the type of the field to “Transformable”, give it a custom class of NSAttributedString, and set the transformer to NSSecureUnarchiveFromData
When I try to save, I first convert the Swift AttributedString to NSAttributedString, and then save the context. Unfortunately I get this error when saving the context, and the save isn't persisted:
CoreData: error: SQLCore dispatchRequest: exception handling request: <NSSQLSaveChangesRequestContext: 0x600003721140> , <shared NSSecureUnarchiveFromData transformer> threw while encoding a value. with userInfo of (null)
Here's the code that tries to save the attributed string:
struct AttributedDetailView: View {
@ObservedObject var item: Item
@State private var notesText = AttributedString()
var body: some View {
VStack {
TextEditor(text: $notesText)
.padding()
.onChange(of: notesText) {
item.attributedString = NSAttributedString(notesText)
}
}
.onAppear {
if let nsattributed = item.attributedString {
notesText = AttributedString(nsattributed)
} else {
notesText = ""
}
}
.task {
item.attributedString = NSAttributedString(notesText)
do {
try item.managedObjectContext?.save()
} catch {
print("core data save error = \(error)")
}
}
}
}
This is the attribute setup in the Core Data model editor:
Is there a workaround for this?
I filed FB17943846 if someone can take a look.
Thanks.
I have an Apple app that uses SwiftData and icloud to sync the App's data across users' devices. Everything is working well. However, I am facing the following issue:
SwiftData does not support public sharing of the object graph with other users via iCloud. How can I overcome this limitation without stopping using SwiftData?
Thanks in advance!
Hi! I use Tips with CloudKit and it works very well, however when a user want to remove their data from CloudKit, how to do that?
In CoreData with CloudKit area, NSPersistentCloudKitContainer have purgeObjectsAndRecordsInZone to delete both local managed objects and CloudKit records, however there is no information about the TipKit deletion.
Does anyone know ideas?
Hello Apple Team,
We are looking at developing an iOS feature on our current development that stores user-generated images as CKAssets in the public CloudKit database, with access control enforced by our app’s own logic (not CloudKit Sharing as that has a limit of 100 shares per device). Each story or post is a public record, and users only see content based on buddy relationships handled within the app.
We’d like to confirm that this pattern is consistent with Apple’s best practices for social features. Specifically:
Is it acceptable to store user-uploaded CKAssets in the public CloudKit database, as long as access visibility is enforced by the app?
Are there any performance or quota limitations (e.g., storage, bandwidth, or user sync limits) that apply to CKAssets in the public database when used at scale?
Would CloudKit Sharing be recommended instead, even if we don’t require user-to-user sharing invitations?
For App Review, is this model (public CKAssets + app-enforced access control) compliant with Apple’s data and security expectations?
Are there any caching or bandwidth optimization guidelines for handling image-heavy public CKAsset data in CloudKit?
Thanks again for your time
Hi, I work on a financial app in Brazil and since Beta 1 we're getting several crashes. We already opened a code level support and a few feedback issues, but haven't got any updates on that yet.
We were able to resolve some crashes changing some of our implementation but we aren't able to understand what might be happening with this last one.
This is the log we got on console:
erro 11:55:41.805875-0300 MyApp CoreData: error: Failed to load NSManagedObjectModel with URL 'file:///private/var/containers/Bundle/Application/0B9F47D9-9B83-4CFF-8202-3718097C92AE/MyApp.app/ServerDrivenModel.momd/'
We double checked and the momd is inside the bundle. The same app works on any other iOS version and if we build using Xcode directly (without archiving and installing on an iOS26 device) it works as expected.
Have anyone else faced a similar error? Any tips or advice on how we can try to solve that?
I am trying to add a custom JSON DataStore and DataStoreConfiguration for SwiftData. Apple kindly provided some sample code in the WWDC24 session, "Create a custom data store with SwiftData", and (once updated for API changes since WWDC) that works fine.
However, when I try to add a relationship between two classes, it fails. Has anyone successfully made a JSONDataStore with a relationship?
Here's my code; firstly the cleaned up code from the WWDC session:
import SwiftData
final class JSONStoreConfiguration: DataStoreConfiguration {
typealias Store = JSONStore
var name: String
var schema: Schema?
var fileURL: URL
init(name: String, schema: Schema? = nil, fileURL: URL) {
self.name = name
self.schema = schema
self.fileURL = fileURL
}
static func == (lhs: JSONStoreConfiguration, rhs: JSONStoreConfiguration) -> Bool {
return lhs.name == rhs.name
}
func hash(into hasher: inout Hasher) {
hasher.combine(name)
}
}
final class JSONStore: DataStore {
typealias Configuration = JSONStoreConfiguration
typealias Snapshot = DefaultSnapshot
var configuration: JSONStoreConfiguration
var name: String
var schema: Schema
var identifier: String
init(_ configuration: JSONStoreConfiguration, migrationPlan: (any SchemaMigrationPlan.Type)?) throws {
self.configuration = configuration
self.name = configuration.name
self.schema = configuration.schema!
self.identifier = configuration.fileURL.lastPathComponent
}
func save(_ request: DataStoreSaveChangesRequest<DefaultSnapshot>) throws -> DataStoreSaveChangesResult<DefaultSnapshot> {
var remappedIdentifiers = [PersistentIdentifier: PersistentIdentifier]()
var serializedData = try read()
for snapshot in request.inserted {
let permanentIdentifier = try PersistentIdentifier.identifier(for: identifier,
entityName: snapshot.persistentIdentifier.entityName,
primaryKey: UUID())
let permanentSnapshot = snapshot.copy(persistentIdentifier: permanentIdentifier)
serializedData[permanentIdentifier] = permanentSnapshot
remappedIdentifiers[snapshot.persistentIdentifier] = permanentIdentifier
}
for snapshot in request.updated {
serializedData[snapshot.persistentIdentifier] = snapshot
}
for snapshot in request.deleted {
serializedData[snapshot.persistentIdentifier] = nil
}
try write(serializedData)
return DataStoreSaveChangesResult<DefaultSnapshot>(for: self.identifier, remappedIdentifiers: remappedIdentifiers)
}
func fetch<T>(_ request: DataStoreFetchRequest<T>) throws -> DataStoreFetchResult<T, DefaultSnapshot> where T : PersistentModel {
if request.descriptor.predicate != nil {
throw DataStoreError.preferInMemoryFilter
} else if request.descriptor.sortBy.count > 0 {
throw DataStoreError.preferInMemorySort
}
let objs = try read()
let snapshots = objs.values.map({ $0 })
return DataStoreFetchResult(descriptor: request.descriptor, fetchedSnapshots: snapshots, relatedSnapshots: objs)
}
func read() throws -> [PersistentIdentifier : DefaultSnapshot] {
if FileManager.default.fileExists(atPath: configuration.fileURL.path(percentEncoded: false)) {
let decoder = JSONDecoder()
decoder.dateDecodingStrategy = .iso8601
let data = try decoder.decode([DefaultSnapshot].self, from: try Data(contentsOf: configuration.fileURL))
var result = [PersistentIdentifier: DefaultSnapshot]()
data.forEach { s in
result[s.persistentIdentifier] = s
}
return result
} else {
return [:]
}
}
func write(_ data: [PersistentIdentifier : DefaultSnapshot]) throws {
let encoder = JSONEncoder()
encoder.dateEncodingStrategy = .iso8601
encoder.outputFormatting = [.prettyPrinted, .sortedKeys]
let jsonData = try encoder.encode(data.values.map({ $0 }))
try jsonData.write(to: configuration.fileURL)
}
}
The data model classes:
import SwiftData
@Model
class Settings {
private(set) var version = 1
@Relationship(deleteRule: .cascade) var hack: Hack? = Hack()
init() {
}
}
@Model
class Hack {
var foo = "Foo"
var bar = 42
init() {
}
}
Container:
lazy var mainContainer: ModelContainer = {
do {
let url = // URL to file
let configuration = JSONStoreConfiguration(name: "Settings", schema: Schema([Settings.self, Hack.self]), fileURL: url)
return try ModelContainer(for: Settings.self, Hack.self, configurations: configuration)
}
catch {
fatalError("Container error: \(error.localizedDescription)")
}
}()
Load function, that saves a new Settings JSON file if there isn't an existing one:
@MainActor func loadSettings() {
let mainContext = mainContainer.mainContext
let descriptor = FetchDescriptor<Settings>()
let settingsArray = try? mainContext.fetch(descriptor)
print("\(settingsArray?.count ?? 0) settings found")
if let settingsArray, let settings = settingsArray.last {
print("Loaded")
} else {
let settings = Settings()
mainContext.insert(settings)
do {
try mainContext.save()
} catch {
print("Error saving settings: \(error)")
}
}
}
The save operation creates a JSON file, which while it isn't a format I would choose, is acceptable, though I notice that the "hack" property (the relationship) doesn't have the correct identifier.
When I run the app again to load the data, I get an error (that there wasn't room to include in this post).
Even if I change Apple's code to not assign a new identifier, so the relationship property and its pointee have the same identifier, it still doesn't load.
Am I doing something obviously wrong, or are relationships not supported in custom data stores?
Hey all,
This is my first app with Swift, and first app using CloudKit / iCloud - although I have launched other iOS app successfully.
When I created the app, I selected "none" for storage
my bundle identifier looks like this: io.mysite.appname
I have the iCloud capability added, with CloudKit checked, and the container also checked that looks like this: iCloud.io.mysite.appname
Push Notificaitons capability is also added, but there is no configuration.
I have tried automatically managed signing, as well as a manually created provisioning profile..
Every time I build the app onto my device - when I check it out in settings, icloud is not listed. When I go through iCloud into icloud drive, the app is also not listed.
I have cleaned the build many times, deleted and reinstalled the app on my phone many times. I am definitely logged into iCloud etc.
Obviously I have spent plenty of times trying to debug with various LLMs, but we all seem to be at a loss for what I'm missing or doing wrong.
Would love any tips or pointers I may be missing, thank you!
Topic:
App & System Services
SubTopic:
iCloud & Data
Is there a way to view the data saved when using swiftdata? Even after deleting all models, the storage space taken up by the app in Settings is too large.
if it set com.apple.CoreData.ConcurrencyDebug 1 as launch arg the app always crashes and i cant proceed into the app. is there a way to only raise a warning for these issues so that i can go into the app and check every place in one session for coredata errors?
Hi,
I'm getting a very odd error log in my SwiftData setup for an iOS app. It is implemented to support schema migration. When starting the app, it simply prints the following log twice (seems to be dependent on how many migration steps, I have two steps in my sample code):
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.
(Yes there is a mistyped word "verison", this is exactly the log)
The code actually fully works. But I have neither CloudKit configured, nor is this app in Production yet. I'm still just developing.
Here is the setup and code to reproduce the issue.
Development mac version: macOS 15.5
XCode version: 16.4
iOS Simulator version: 18.5
Real iPhone version: 18.5
Project name: SwiftDataDebugApp
SwiftDataDebugApp.swift:
import SwiftUI
import SwiftData
@main
struct SwiftDataDebugApp: App {
var sharedModelContainer: ModelContainer = {
let schema = Schema([
Item.self,
])
let modelConfiguration = ModelConfiguration(schema: schema, isStoredInMemoryOnly: false, allowsSave: true)
do {
return try ModelContainer(for: schema, migrationPlan: ModelMigraitonPlan.self, configurations: [modelConfiguration])
} catch {
fatalError("Could not create ModelContainer: \(error)")
}
}()
var body: some Scene {
WindowGroup {
ContentView()
}
.modelContainer(sharedModelContainer)
}
}
Item.swift:
import Foundation
import SwiftData
typealias Item = ModelSchemaV2_0_0.Item
enum ModelSchemaV1_0_0: VersionedSchema {
static var versionIdentifier = Schema.Version(1, 0, 0)
static var models: [any PersistentModel.Type] {
[Item.self]
}
@Model
final class Item {
var timestamp: Date
init(timestamp: Date) {
self.timestamp = timestamp
}
}
}
enum ModelSchemaV2_0_0: 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 tags: [Tag] = []
init(timestamp: Date, tags: [Tag]) {
self.timestamp = timestamp
self.tags = tags
}
}
}
enum ModelMigraitonPlan: SchemaMigrationPlan {
static var schemas: [any VersionedSchema.Type] {
[ModelSchemaV1_0_0.self]
}
static var stages: [MigrationStage] {
[migrationV1_0_0toV2_0_0]
}
static let migrationV1_0_0toV2_0_0 = MigrationStage.custom(
fromVersion: ModelSchemaV1_0_0.self,
toVersion: ModelSchemaV2_0_0.self,
willMigrate: nil,
didMigrate: { context in
let items = try context.fetch(FetchDescriptor<ModelSchemaV2_0_0.Item>())
for item in items {
item.tags = Array(repeating: "abc", count: Int.random(in: 0...3)).map({ Tag(value: $0) })
}
try context.save()
}
)
}
Tag.swift:
import Foundation
struct Tag: Codable, Hashable, Comparable {
var value: String
init(value: String) {
self.value = value
}
static func < (lhs: Tag, rhs: Tag) -> Bool {
return lhs.value < rhs.value
}
static func == (lhs: Tag, rhs: Tag) -> Bool {
return lhs.value == rhs.value
}
func hash(into hasher: inout Hasher) {
hasher.combine(value)
}
}
ContentView.swift:
import SwiftUI
import SwiftData
struct ContentView: View {
@Environment(\.modelContext) private var modelContext
@Query private var items: [Item]
var body: some View {
VStack {
List {
ForEach(items) { item in
VStack(alignment: .leading) {
Text(item.timestamp, format: Date.FormatStyle(date: .numeric, time: .standard))
HStack {
ForEach(item.tags, id: \.hashValue) { tag in
Text("\(tag.value)")
}
}
}
}
.onDelete(perform: deleteItems)
}
Button("Add") {
addItem()
}
.padding(.top)
}
}
private func addItem() {
withAnimation {
let newItem = Item(timestamp: Date(), tags: [Tag(value: "Hi")])
modelContext.insert(newItem)
}
do {
try modelContext.save()
} catch {
print("Error saving add: \(error.localizedDescription)")
}
}
private func deleteItems(offsets: IndexSet) {
withAnimation {
for index in offsets {
modelContext.delete(items[index])
}
}
do {
try modelContext.save()
} catch {
print("Error saving delete: \(error.localizedDescription)")
}
}
}
#Preview {
ContentView()
.modelContainer(for: Item.self, inMemory: true)
}
I hope someone can help, couldn't find anything related to this log at all.
One question I often see on DevForums and in my day DTS job is if a Core Data object managed by NSPersistentCloudKitContainer can be shared with other iCloud users.
The answer is yes but you need to do it using CloudKit API directly because NSPersistentCloudKitContainer doesn’t support CloudKit shared database (CKContainer.sharedCloudDatabase) today.
Assuming you have a Core Data object, let’s say a document, that you’d like to collaborate with your colleagues:
You are the document owner and can use NSPersistentCloudKitContainer to fully manages the document and synchronize it across your devices.
You can grab a CloudKit record associated with your document from NSPersistentCloudKitContainer using record(for:) or recordID(for:), and share it to your colleagues using UICloudSharingController. See our Sharing CloudKit Data with Other iCloud Users - https://developer.apple.com/documentation/cloudkit/sharing_cloudkit_data_with_other_icloud_users sample for how to share a CloudKit record.
After accepting the sharing, your colleague, as a participant, can view or edit the shared document. The document resides in the participant’s CloudKit shared database and you have to manage it with your own code.
When your colleague edits and saves the shared document, the changes go to the owner’s private database, and eventually synchronize to NSPersistentCloudKitContainer on the owner side.
As you can see, you need to implement #2 and #3 with your own code because NSPersistentCloudKitContainer can’t manage the data in the participant's shared database. If you have any difficulty after going through the above sample code, you can contact Apple’s DTS for help.
I'm experiencing the following error with my SwiftData container when running a build:
Code=134504 "Cannot use staged migration with an unknown model version."
Code Structure - Summary
I am using a versionedSchema to store multiple models in SwiftData. I started experiencing this issue when adding two new models in the newest Schema version. Starting from the current public version, V4.4.6, there are two migrations.
Migration Summary
The first migration is to V4.4.7. This is a lightweight migration removing one attribute from one of the models. This was tested and worked successfully.
The second migration is to V5.0.0. This is a custom migration adding two new models, and instantiating instances of the two new models based on data from instances of the existing models. In the initial testing of this version, no issues were observed.
Issue and Steps to Reproduce
Reproduction of issue: Starting from a fresh build of the publicly released V4.4.6, I run a new build that contains both Schema Versions (V4.4.7 and V5.0.0), and their associated migration stages. This builds successfully, and the container successfully migrates to V5.0.0. Checking the default.store file, all values appear to migrate and instantiate correctly.
The second step in reproduction of the issue is to simply stop running the build, and then rebuild, without any code changes. This fails to initialize the model container every time afterwards. Going back to the simulator after successive builds are stopped in Xcode, the app launches and accesses/modifies the model container as normal.
Supplementary Issue: I have been putting up with the same, persistent issue in the Xcode Preview Canvas of "Failed to Initialize Model Container" This is a 5 in 6 build issue, where builds will work at random. In the case of previews, I have cleared all data associated with all previews multiple times. The only difference being that the simulator is a 100% failure rate after the initial, successful initialization. I assume this is due to the different build structure of previews. Lastly, of note, the Xcode previews fail at the same line in instantiating the model container as the simulator does. From my research into this issue, people say that the Xcode preview is instantiating from elsewhere. I do have a separate model container set up specifically for canvas previews, but the error does not occur in that container, but rather the app's main container.
Possible Contributing Factors & Tested Facts
iOS: While I have experienced issues with SwiftData and the complier in iOS 26, I can rule that out as the issue here. This has been tested on simulators running iOS 18.6, 26.0.1, and 26.1, all encountering failures to initialize model container. While in iOS 18, subsequent builds after the successful migration did work, I did eventually encounter the same error and crash. In iOS 26.0.1 and 26.1, these errors come immediately on the second build.
Container Initialization for V4.4.6
do {
container = try ModelContainer(
for:
Job.self,
JobTask.self,
Day.self,
Charge.self,
Material.self,
Person.self,
TaskCategory.self,
Service.self,
migrationPlan: JobifyMigrationPlan.self
)
} catch {
fatalError("Failed to Initialize Model Container")
}
Versioned Schema Instance for V4.4.6 (V4.4.7 differs only by versionIdentifier)
static var versionIdentifier = Schema.Version(4, 4, 6)
static var models: [any PersistentModel.Type] {
[Job.self, JobTask.self, Day.self, Charge.self, Material.self, Person.self, TaskCategory.self, Service.self]
}
Container Initialization for V5.0.0
do {
let schema = Schema([Jobify.self,
JobTask.self,
Day.self,
Charge.self,
MaterialItem.self,
Person.self,
TaskCategory.self,
Service.self,
ServiceJob.self,
RecurerRule.self])
container = try ModelContainer(
for: schema, migrationPlan: JobifyMigrationPlan.self
)
} catch {
fatalError("Failed to Initialize Model Container")
}
Versioned Schema Instance for V5.0.0
static var versionIdentifier = Schema.Version(5, 0, 0)
static var models: [any PersistentModel.Type] {
[
JobifySchemaV500.Job.self,
JobifySchemaV500.JobTask.self,
JobifySchemaV500.Day.self,
JobifySchemaV500.Charge.self,
JobifySchemaV500.Material.self,
JobifySchemaV500.Person.self,
JobifySchemaV500.TaskCategory.self,
JobifySchemaV500.Service.self,
JobifySchemaV500.ServiceJob.self,
JobifySchemaV500.RecurerRule.self
]
}
Addressing Differences in Object Names
Type-aliasing: All my model types are type-aliased for simplification in view components. All types are aliased as 'JobifySchemeV446.<#Name#>' in V.4.4.6, and 'JobifySchemaV500.<#Name#>' in V5.0.0
Issues with iOS 26: My type-aliases dating back to iOS 17 overlapped with lower level objects in Swift, including 'Job' and 'Material'. These started to be an issue with initializing the model container when running in iOS 26. The type aliases have been renamed since, however the V4.4.6 build with the old names runs and builds perfectly fine in iOS 26
If there is any other code that may be relevant in determining where this error is occurring, I would be happy to add it. My current best theory is simply that I have mistakenly omitted code relevant to the SwiftData Migration.
My use case is the following:
Every user of my app can create as an owner a set of items.
These items are private until the owner invites other users to share all of them as participant.
The participants can modify the shared items and/or add other items.
So, sharing is not done related to individual items, but to all items of an owner.
I want to use CoreData & CloudKit to have local copies of private and shared items.
To my understanding, CoreData & CloudKit puts all mirrored items in a special zone „com.apple.coredata.cloudkit.zone“.
So, this zone should be shared, i.e. all items in it.
In the video it is said that NSPersistentCloudKitContainer uses Record Zone Sharing optionally in contrast to hierarchically record sharing using a root record.
But how is this done?
Maybe I can declare zone „com.apple.coredata.cloudkit.zone“ as a shared zone?
Topic:
App & System Services
SubTopic:
iCloud & Data
Tags:
Cloud and Local Storage
UI Frameworks
wwdc21-10015
I have been working on an app for the past few months, and one issue that I have encountered a few times is an error where quick subsequent deletions cause issues with detached tasks that are triggered from some user actions.
Inside a Task.detached, I am building an isolated model context, querying for LineItems, then iterating over those items. The crash happens when accessing a Transaction property through a relationship.
var byTransactionId: [UUID: [LineItem]] {
return Dictionary(grouping: self) { item in
item.transaction?.id ?? UUID()
}
}
In this case, the transaction has been deleted, but the relationship existed when the fetch occurred, so the transaction value is non-nil. The crash occurs when accessing the id. This is the error.
SwiftData/BackingData.swift:1035: Fatal error: This model instance was invalidated because its backing data could no longer be found the store. PersistentIdentifier(id: SwiftData.PersistentIdentifier.ID(backing: SwiftData.PersistentIdentifier.PersistentIdentifierBacking.managedObjectID(0xb43fea2c4bc3b3f5 <x-coredata://A9EFB8E3-CB47-48B2-A7C4-6EEA25D27E2E/Transaction/p1756>)))
I see other posts about this error and am exploring some suggestions, but if anyone has any thoughts, they would be appreciated.
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!!
If use a SortDescriptor for a model and sort by some attribute from a relationship, in DEBUG mode it all works fine and sorts. However, in release mode, it is an instant crash.
SortDescriptor(.name, order: .reverse) ---- works
SortDescriptor(.assignedUser?.name, order: .reverse) ---- works in debug but crash in release.
What is the issue here, is it that SwiftData just incompetent to do this?
I have a SwiftData application that is using CloudKit. If user is on new device. How can I check and fetch data, instead of just waiting for it happen on its own randomly?
For example, I have onboarding which I do not want user to go through again if they already have an active installation.
Seems like SwiftData is severely limited in pretty much every way, specially any useful CloudKit debugging or control functionality.