Hi all,
I recently discovered that I forgot to deploy my CloudKit schema changes from development to production - an oversight that unfortunately went unnoticed for 2.5 months.
As a result, any data created during that time was never synced to iCloud and remains only in the local CoreData store. Once I pushed the schema to production, CloudKit resumed syncing new changes as expected.
However, this leaves me with a gap: there's now a significant amount of data that would be lost if users delete or reinstall the app.
Before I attempt to implement a manual backup or migration strategy, I was wondering:
Does NSPersistentCloudKitContainer keep track of local changes that couldn't be synced doe to the missing schema and automatically reattempt syncing them now that the schema is live?
If not, what would be the best approach to ensure this "orphaned" data gets saved to CloudKit retroactively.
Thanks in advance for any guidance or suggestions.
iCloud & Data
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Hello,
After iOS 18 fetchChanges() method of CloudKitSync engine does not work as before. Calling the function doesn't fetch changes always, but it does fetch on iOS 17.
However going background and foreground again fetches changes automatically.
I have a simple model
@Model
final class Movie: Identifiable {
#Index\<Movie\>(\[.name\])
var id = UUID()
var name: String
var genre: String?
init(name: String, genre: String?) {
self.name = name
self.genre = genre
}
}
I turned on SQL debugging by including '-com.apple.CoreData.SQLDebug 3' argument on launch.
When I fetch the data using the following code, it selects 3 records initially, but then also selects each record individually even though I am not referencing any other attributes.
var fetchDescriptor = FetchDescriptor\<Movie\>()
fetchDescriptor.propertiesToFetch = \[.id, .name\]
fetchDescriptor.fetchLimit = 3
do {
print("SELECT START")
movies = try modelContext.fetch(fetchDescriptor)
print("SELECT END")
} catch {
print("Failed to load Movie model.")
}
I see it selecting the 3 rows initially, but then it selects each one separately. Why would it do this on the initial fetch? I was hoping to select the data that I want to display and let the system select the entire record only when I access a variable that I did not initially fetch.
CoreData: annotation: fetch using NSSQLiteStatement <0x600002158af0> on entity 'Movie' with sql text 'SELECT 1, t0.Z_PK, t0.ZID, t0.ZNAME FROM ZMOVIE t0 LIMIT 3' returned 3 rows with values: (
"<NSManagedObject: 0x600002158d70> (entity: Movie; id: 0xa583c7ed484691c1 <x-coredata://71E60F4C-1A40-4DB7-8CD1-CD76B4C11949/Movie/p1>; data: <fault>)",
"<NSManagedObject: 0x600002158d20> (entity: Movie; id: 0xa583c7ed482691c1 <x-coredata://71E60F4C-1A40-4DB7-8CD1-CD76B4C11949/Movie/p2>; data: <fault>)",
"<NSManagedObject: 0x600002158f00> (entity: Movie; id: 0xa583c7ed480691c1 <x-coredata://71E60F4C-1A40-4DB7-8CD1-CD76B4C11949/Movie/p3>; data: <fault>)"
)
CoreData: annotation: fetch using NSSQLiteStatement <0x600002154d70> on entity 'Movie' with sql text 'SELECT 0, t0.Z_PK, t0.Z_OPT, t0.ZGENRE, t0.ZID, t0.ZNAME FROM ZMOVIE t0 WHERE t0.Z_PK = ? ' returned 1 rows
CoreData: annotation: with values: (
"<NSSQLRow: 0x600000c89500>{Movie 1-1-1 genre=\"Horror\" id=4C5CB4EB-95D7-4DC8-B839-D4F2D2E96ED0 name=\"A000036\" and to-manys=0x0}"
)
This all happens between the SELECT START and SELECT END print statements. Why is it fulfilling the faults immediately?
I previously got this error when I used a PassKey to log in. I'm not using that. I've put my password in multiple times, closed the browser, etc. It doesn't seem to be working. The only thing I can think is that because my Mac is using a different iCloud account, it's not letting me.
Does anyone have any ideas?
Greetings i have an app that uses three different SwiftData models and i want to know what is the best way to use the them accross the app. I though a centralized behaviour and i want to know if it a correct approach.First let's suppose that the first view of the app will load the three models using the @Enviroment that work with @Observation. Then to other views that add data to the swiftModels again with the @Environment. Another View that will use the swiftData models with graph and datas for average and min and max.Is this a corrent way? or i should use @Query in every view that i want and ModelContext when i add the data.
@Observable
class CentralizedDataModels {
var firstDataModel: [FirstDataModel] = []
var secondDataModel: [SecondDataModel] = []
var thirdDataModel: [ThirdDataModel] = []
let context: ModelContext
init(context:ModelContext) {
self.context = context
}
}
I want to clear all the data in the zone, but I can't delete it. Below is my code, no logs are printed when running.
static func clearData() {
let coordinator = shared.container.persistentStoreCoordinator
let fm = FileManager.default
for d in shared.container.persistentStoreDescriptions {
guard let url = d.url else { continue }
do {
if fm.fileExists(atPath: url.path()) {
try coordinator.destroyPersistentStore(at: url, type: .sqlite)
}
} catch {
logger.debug("Failed to delete db file, \(error)")
}
}
for description in shared.container.persistentStoreDescriptions {
guard let originalStoreURL = description.url else { continue }
let walFileURL = originalStoreURL.deletingPathExtension().appendingPathExtension("sqlite-wal")
let shmFileURL = originalStoreURL.deletingPathExtension().appendingPathExtension("sqlite-shm")
for url in [originalStoreURL, walFileURL, shmFileURL] {
do {
if fm.fileExists(atPath: url.path()) {
try fm.removeItem(at: url)
}
} catch {
logger.debug("Failed to delete db file, \(error)")
}
}
}
let container = CKContainer(identifier: appContainerID)
container.privateCloudDatabase.fetchAllRecordZones { zones, error in
if let error = error {
print("Error fetching zones: ")
} else if let zone = zones?.first, zone.zoneID.zoneName == "_defaultZone" {
PersistenceController.shared.container.purgeObjectsAndRecordsInZone(with: zone.zoneID, in: nil) { ckShare, error in
if let error = error {
print("Error purge zones: \(error)")
}
if ckShare == nil {
print("ckShare is nil")
}
}
}
}
}
Hello! 😊
I currently manage an app called MoneyKeeper that uses SwiftData for its data storage framework. Many users have requested a "sharing" feature, but unfortunately, SwiftData does not yet support this functionality, and it’s unclear when it will. 😭
Initially, I considered using CloudKit and CKSyncEngine to implement quick synchronization and sharing. However, due to the complexity of the current data model’s relationships, modeling it with CloudKit’s schema alone seemed overly complicated and likely to introduce bugs.
As a result, I’ve decided to implement the sharing feature using CoreData and CloudKit. My plan to avoid conflicts with SwiftData includes:
Keeping the local storage locations for SwiftData and CoreData separate.
Using entirely separate CloudKit containers for SwiftData and CoreData.
I believe these measures will minimize potential issues, but I’m wondering if there’s anything else I should consider.
Using both SwiftData (for the personal database) and CoreData (for the shared database) feels like it could lead to significant technical debt in the future, and I anticipate encountering even more challenges during actual implementation.
I’d greatly appreciate your valuable insights on this matter. 🙏
The app MoneyKeeper, currently operated using SwiftData.
https://apps.apple.com/app/id6514279917
I've developed an app that allow me to send messages to all users by entering a record in Public database. On each users device, the app takes that Public record and creates a record in their Private database to track the Read and Deleted status.
It works flawlessly on the simulator and about 1/3 of the devices enrolled in my TestFlight. The other 2/3 are unable to write to their Private database. In fact, the CKContainer.default().privateCloudDatabase.save() operation causes the app to crash if I let it run.
I've looked at every Google link and I just can't figure out why this works for 1/3 of the users, but not the other 2/3. Incidentally, the 2/3 of the group that can't save to their Private database are also unable to save their Notification Subscription.
All devices are running iOS 18.0 or better iPhone 11 through 16 in testing pool. Each portion of the working/not working group are a mix of iPhone versions.
if !found && checkIcloudStatus() {
CKContainer.default().privateCloudDatabase.save(loadPrivateData(n: processedMessages[index].recordName)) { returnedRecord, returnedError in
print("Adding new message to Private and error is: \(String(describing: returnedError))")
DispatchQueue.main.async {
self.processedMessages[index].record = returnedRecord ?? CKRecord(recordType: "messages_private")
self.processedMessages[index].unRead = true
self.processedMessages[index].deleted = false
}
}
}
func loadPrivateData(n: String) -> CKRecord {
let record = CKRecord(recordType: "messages_private")
record["deleted"] = "false"
record["messageId"] = n
record["unRead"] = "true"
return record
}
Hi, I am building an iOS app with SwiftUI and SwiftData for the first time and I am experiencing a lot of difficulty with this error:
Thread 44: Fatal error: Never access a full future backing data - PersistentIdentifier(id: SwiftData.PersistentIdentifier.ID(backing: SwiftData.PersistentIdentifier.PersistentIdentifierBacking.managedObjectID(<ID> <x-coredata://<UUID>/MySwiftDataModel/p1>)), backing: SwiftData.PersistentIdentifier.PersistentIdentifierBacking.managedObjectID(<ID> <x-coredata://<UUID>/MySwiftDataModel/p1>)) with Optional(<UUID>)
I have been trying to figure out what the problem is, but unfortunately I cannot find any information in the documentation or on other sources online. My only theory about this error is that it is somehow related to fetching an entity that has been created in-memory, but not yet saved to the modelContext in SwiftData.
However, when I am trying to debug this, it's not clear this is the case. Sometimes the error happens, sometimes it doesn't. Saving manually does not always solve the error.
Therefore, it would be extremely helpful if someone could explain what this error means and whether there are any best practices to do with SwiftData, or some pitfalls to avoid (such as wrapping my model context into a repository class).
To be clear, this problem is NOT related to one area of my code, it happens throughout my app, at unpredictable places and time. Given that there is very little information related to this error, I am at a loss at how to make sure that this never happens.
This question has been asked on the forum here as well as on StackOverflow, Reddit (can't link that here), but none of the answers worked for me.
For reference, my models generally look like this:
import Foundation
import SwiftData
@Model
final class MySwiftDataModel {
// Stable cross-device identity
@Attribute(.unique)
var uuid: UUID
var someNumber: Int
var someString: String
@Relationship(deleteRule: .nullify, inverse: \AnotherSwiftDataModel.parentModel)
var childModels: [AnotherSwiftDataModel]
init(uuid: UUID = UUID(), someNumber: Int = 1, someString: String = "Some", childModels: [AnotherSwiftDataModel] = []) {
self.uuid = uuid
self.someNumber = someNumber
self.someString = someString
self.childModels = childModels
}
func addChildModel(model: AnotherSwiftDataModel) {
self.childModels.append(model)
}
func removeChildModel(by id: PersistentIdentifier) {
self.childModels = self.childModels.filter { $0.id != id }
}
}
and the child model:
import Foundation
import SwiftData
@Model
final class AnotherSwiftDataModel {
// Stable cross-device identity
@Attribute(.unique)
var uuid: UUID
var someNumber: Int
var someString: String
var parentModel: MySwiftDataModel?
init(uuid: UUID = UUID(), someNumber: Int = 1, someString: String = "Some") {
self.uuid = uuid
self.someNumber = someNumber
self.someString = someString
}
}
For now, you can assume I am not using CloudKit - i know for a fact the error is unrelated to CloudKit, because it happens when I am not using CloudKit (so I do not need to follow CloudKit's requirements for model design, such as nullable values etc).
As I said, the error surfaces at different times - sometimes during assignments, a lot of times during deletions of related models, etc.
Could you please explain what I am doing wrong and how I can make sure that this error does not happen? What are the architectural patterns that work best for SwiftData in this case? Do you have any examples of things I should avoid?
Thanks
Hello,
I recently switched my app from flutter which was using sqlite3 database. I would like to migrate my existing users to SwiftData.
The issue is I do not know where to start in finding the database for the current users, reading the data and inserting into the SwiftData schema.
I tried searching but not clear on how to proceed. Any help pointing in the right direction would be great. Thanks.
I have a CoreData model with two configuration - but several problems. Notably the viewContext only shows data from the .private configuration. Here is the setup:
The private configuration holds entities, for example, User and Course and the shared one holds entities, for example, Player and League. I setup the NSPersistentStoreDescriptions to use the same container but with a databaseScope of .private/.shared and with the configuration of "Private"/"Shared". loadPersistentStores() does not report an error.
If I try container.initializeCloudKitSchema() only the .private configuration produces CKRecord types. If I create a companion app using one configuration (w/ all entities) the schema initialization creates all CKRecord types AND I can populate some data in the .private and a created CKShare. I see that data in the CloudKit dashboard.
If I axe the companion app and run the real thing w/ two configurations, the viewContext only has the .private data. Why?
If when querying history I use NSPersistentHistoryTransaction.fetchRequest I get a nil return when using two configurations (but non-nil when using one).
When the following models in SwiftData,
@Model
final class UndoRedoData {
var id: [Int]
init(id: [Int]) {
self.id = id
}
}
I created the following code.
struct ContentView: View {
@ObservedObject var swiftDataViewModel = SwiftDataArrayViewModel.shared
@State private var idArray: [Int] = [1,2,3,4]
@State private var firstviewSwich: Bool = true
@State private var twoviewSwich: Bool = false
@State private var threeviewSwich: Bool = false
var body: some View {
VStack {
if firstviewSwich == true {
Button(action: addItem) {
Text("1.New Item")
}
}
if twoviewSwich == true {
Button {
forArrayData()
} label: {
Text("2.Data Road")
}
}
if threeviewSwich == true {
Button(action: undoItem) {
Text("3.Undo")
}
}
}
}
private func addItem() {
withAnimation {
let newItem = UndoRedoData(id: [1,2,3,4])
swiftDataViewModel.taskContext.insert(newItem)
do {
try swiftDataViewModel.taskContext.save()
} catch {
print(error)
}
swiftDataViewModel.fetchItems()
firstviewSwich.toggle()
twoviewSwich.toggle()
}
}
private func forArrayData() {
twoviewSwich.toggle()
for data in idArray {
swiftDataViewModel.idUndoCreate(id: data, undoManager: swiftDataViewModel.arrayItemUndoManager)
}
threeviewSwich.toggle()
}
private func undoItem() {
swiftDataViewModel.arrayItemUndoManager.undo()
threeviewSwich.toggle()
firstviewSwich.toggle()
}
}
class SwiftDataArrayViewModel: ObservableObject {
static let shared = SwiftDataArrayViewModel()
let modelContainer: ModelContainer
@ObservationIgnored
lazy var taskContext: ModelContext = {
return ModelContext(modelContainer)
}()
@Published var arrayItems = [UndoRedoData]()
@Published var arrayItemUndoManager = UndoManager()
init() {
let schema = Schema([UndoRedoData.self])
let modelConfiguration = ModelConfiguration(schema: schema, isStoredInMemoryOnly: false)
do {
modelContainer = try ModelContainer(for: schema, configurations: [modelConfiguration])
} catch {
fatalError(error)
}
fetchItems()
}
func fetchItems() {
let fetchDescriptor = FetchDescriptor<UndoRedoData>()
do {
arrayItems = try taskContext.fetch(fetchDescriptor)
} catch {
fatalError(error)
}
}
func idUndoCreate(id: Int, undoManager: UndoManager?) {
undoManager?.registerUndo(withTarget: self) { target in
target.removeID()
}
}
func removeID() {
if let firstUndoRedoData = arrayItems.first {
print("Before Delete:\(firstUndoRedoData.id)")
if !firstUndoRedoData.id.isEmpty {
firstUndoRedoData.id.removeLast()
}
print("After Delete:\(firstUndoRedoData.id)")
}
do {
try taskContext.save()
} catch {
print(error)
}
fetchItems()
}
}
In this code, 1. Create an Item in New Item, 2. Execute Data Road and register the data in the array that is the same value as the data created in New Item in SwiftData one by one in UndoManager by for data in idArray.
This is done because the data in the array and the data created by New Item in SwiftData can be known in advance.
private func forArrayData() {
twoviewSwich.toggle()
for data in idArray {
swiftDataViewModel.idUndoCreate(id: data, undoManager: swiftDataViewModel.arrayItemUndoManager)
}
// class SwiftDataArrayViewModel: ObservableObject
func idUndoCreate(id: Int, undoManager: UndoManager?) {
undoManager?.registerUndo(withTarget: self) { target in
target.removeID()
}
}
After registering in UndoManager, when Undo is executed with 3. Undo, instead of being able to perform Undo where one id is deleted each time, all the data of the id in SwiftData is deleted in a one-time Undo.
I would like to be able to delete one id each time Undo is performed and restore them in sequence, but I can only delete them all once. Does this mean that such registration to UndoManager should not be done with for statements, etc.? Or is there another problem in the code?
I want to make sure that one id is deleted for each Undo executed.
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?
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.
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?
Is it ok to have latency about 4 sec? The amount of downloaded data is less than 1 MB. Maybe I need to setup an index for every field requested?
I have developed an podcast app, where subscriped podcast & episodes synched with iCloud.
So its working fine with iOS & iPad with latest os version, but iCloud not synching in iPod with version 15.
Please help me to fix this.
Thanks
Devendra K.
I'm working on an app that is using Core Data. I have a custom big number class that boils down to a double and an integer, plus math functions. I've been using transformable types to store these big numbers, but its forcing me to do a lot of ugly casts since the number class is used throughout the application. I figure I can either have my stored values be named differently (e.g. prefix with underscore) and have a computed variable to cast it to the correct type, or find some way to move the big number class to being an NSManagedObject. The issue with this is that the inverse relationships would be massive for the big number class, since multiple entities use the class in multiple properties already. Would it be recommended that I just keep using Transformable types and casts to handle this, or is there some standard way to handle a case like this in Core Data relationships?
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: $text)
.onChange(of: text, initial: false) {
lines = [Line(content: "test line", production: production)]
}
.toolbar {
Button("Done") {
dismiss()
}
}
}
}
}
@Model
class Production {
@Attribute(.unique) var title: String
@Relationship(deleteRule: .cascade, inverse: \Line.production)
var lines: [Line] = []
init(title: String) {
self.title = title
}
}
@Model
class Line {
var content: String
var production: Production?
init(content: String, production: Production?) {
self.content = content
self.production = production
}
}
I have a @Model class that is comprised of a String and a custom Enum. It was working until I added raw String values for the enum cases, and afterwards this error and code displays when opening a view that uses the class:
{
@storageRestrictions(accesses: _$backingData, initializes: _type)
init(initialValue) {
_$backingData.setValue(forKey: \.type, to: initialValue)
_type = _SwiftDataNoType()
}
get {
_$observationRegistrar.access(self, keyPath: \.type)
return self.getValue(forKey: \.type)
}
set {
_$observationRegistrar.withMutation(of: self, keyPath: \.type) {
self.setValue(forKey: \.type, to: newValue)
}
}
}
Thread 1: EXC_BREAKPOINT (code=1, subcode=0x1cc165d0c)
I removed the String raw values but the error persists. Any guidance would be greatly appreciated. Below is replicated code:
@Model
class CopingSkillEntry {
var stringText: String
var case: CaseType
init(stringText: String, case: CaseType) {
self.stringText = stringText
self.case = case
}
}
enum CaseType: Codable, Hashable {
case case1
case case1
case case3
}