The problem is that the iCloud Drive directory of my app does not appear in my iCloud Drive in Finder despite the (I think) correct settings in my info.plist file (see below).
In Terminal, I can see the folder and it also contains .txt files.
What can I do to make the folder visible in Finder and the Files app?
<key>NSUbiquitousContainers</key> <dict> <key>iCloud.vmk.NewsSwiper</key> <dict> <key>NSUbiquitousContainerIsDocumentScopePublic</key> <true/> <key>NSUbiquitousContainerName</key> <string>RSS-Filter</string> <key>NSUbiquitousContainerIdentifier</key> <string>iCloud.vmk.NewsSwiper</string> <key>NSUbiquitousContainerSupportedFolderLevels</key> <string>Any</string> </dict> </dict>
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I have the following lines of code to access data through CoreData.
import Foundation
import CoreData
import CloudKit
class CoreDataManager {
static let instance = CoreDataManager()
let container: NSPersistentCloudKitContainer
let context: NSManagedObjectContext
init() {
container = NSPersistentCloudKitContainer(name: "ABC")
container.loadPersistentStores(completionHandler: { (storeDescription, error) in
if let error = error as NSError? {
print(error.userInfo)
}
})
context = container.viewContext
context.automaticallyMergesChangesFromParent = true
context.mergePolicy = NSMergePolicy(merge: .mergeByPropertyObjectTrumpMergePolicyType)
}
func save() {
do {
try container.viewContext.save()
print("Saved successfully")
} catch {
print("Error in saving data: \(error.localizedDescription)")
}
}
}
I have confirmed that I can share data between iPhone and iPad. Now, I need to use AppGroup as well. I have changed my code as follows.
import Foundation
import CoreData
import CloudKit
class CoreDataManager {
static let shared = CoreDataManager()
let container: NSPersistentContainer
let context: NSManagedObjectContext
init() {
container = NSPersistentCloudKitContainer(name: "ABC")
container.persistentStoreDescriptions = [NSPersistentStoreDescription(url: FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: "some group name")!.appendingPathComponent("CoreDataMama.sqlite"))]
container.loadPersistentStores(completionHandler: { (description, error) in
if let error = error as NSError? {
print("Unresolved error \(error), \(error.userInfo)")
}
})
context = container.viewContext
context.automaticallyMergesChangesFromParent = true
context.mergePolicy = NSMergePolicy(merge: .mergeByPropertyObjectTrumpMergePolicyType)
}
func save() {
do {
try container.viewContext.save()
print("Saved successfully")
} catch {
print("Error in saving data: \(error.localizedDescription)")
}
}
}
Other files being unaltered, my sample apps aren't sharing data. What am I doing wrong? Just FYI, I'm using actual devices. Thank you for your reading this topic.
I am trying to migrate my Core Data model to a new version with a new attribute added to it. Since my app supports macOS 13 I am not able to use the newly introduced Staged migrations.
After much digging I found that the app is not able to find the Mapping Model when one of the attribute has "Preserve after deletion" enabled.
I have enabled migration debbuging using
com.apple.CoreData.MigrationDebug 1
I am getting following error
error: CoreData: error: (migration) migration failed with error Error Domain=NSCocoaErrorDomain Code=134140 "Persistent store migration failed, missing mapping model."
What is the way out here?
I'm using SwiftData with CloutKit with a very simple app. Data syncs between iOS, iPadOS, and visionOS, but not macOS. From what I can tell, macOS is never getting CK messages unless I'm running the app from Xcode.
I can listen for the CK messages and show a line in a debug overlay. This works perfectly when I run from Xcode. I can see the notifications and see updates in my app. However, if I just launch the app outside of Xcode I will never see any changes or notifications. It is as if the Mac app never even tries to contact CloudKit.
Schema has been deployed in the CloudKit console. The app is based on the multi-platform Xcode template. Again, only the macOS version has this issue. Is there some extra permission or setting I need to set up in order to use CloudKit on macOS?
@State private var publisher = NotificationCenter.default.publisher(for: NSPersistentCloudKitContainer.eventChangedNotification).receive(on: DispatchQueue.main)
.onReceive(publisher) { notification in
// Listen for changes in CK events
if let userInfo = notification.userInfo,
let event = userInfo[NSPersistentCloudKitContainer.eventNotificationUserInfoKey] as? NSPersistentCloudKitContainer.Event {
let message = "CloudKit Sync: \(event.type.rawValue) - \(event.succeeded ? "Success" : "Failed") - \(event.description)"
// Store for UI display
syncNotifications.append(message)
if syncNotifications.count > 10 {
syncNotifications.removeFirst()
}
}
}
.overlay(alignment: .topTrailing) {
if !syncNotifications.isEmpty {
VStack(alignment: .leading) {
ForEach(syncNotifications, id: \.self) { notification in
Text(notification)
.padding(8)
}
}
.frame(width: 800, height: 500)
.cornerRadius(8)
.background(Color.secondary.opacity(0.2))
.padding()
.transition(.move(edge: .top))
}
}
Some of my customer get the following CloudKit error (I cannot reproduce is myself).
Failed to modify some records (CKErrorDomain:2)
userInfo: CKErrorDescription:Failed to modify some records CKPartialErrors:{
"<CKRecordID: ooo; recordName=ooo, zoneID=ooo:__defaultOwner__>"
= "<CKError 0x600003809ce0: \"Limit Exceeded\" (27/2023); server message = \"AssetUploadTokenRetrieveRequest request size exceeds limit\";
op = ooo; uuid = ooo; container ID = \"ooo\">"
This is a CKError.limitExeeded error.
I create 200 or less records in a batch operation. So I am below the 400 limit.
Searching the Internet for "AssetUploadTokenRetrieveRequest request size exceeds limit": 0 results
Can anyone give me a hint?
I'm working through the Develop In Swift tutorial at page
[https://developer.apple.com/tutorials/develop-in-swift/navigation-editing-and-relationships-conclusion)]
The tutorial has a one to many relationship between Friend and Movie (each friend can have at most one favorite movie and each movie can be the favorite for zero or more friends).
An exercise left to the student is to use an .onDelete on the movie detail page to delete that movie as favorite.
I modified the Form
Form {
TextField("Movie title", text: $movie.title)
DatePicker("Release date", selection: $movie.releaseDate, displayedComponents: .date)
if !movie.favoritedBy.isEmpty {
Section("Favorited by") {
ForEach(sortedFriends) { friend in
Text(friend.name)
}
.onDelete(perform: deleteFavorites(indexes:))
}
}
}
by adding the .onDelete clause
I added
private func deleteFavorites(indexes: IndexSet) {
for index in indexes {
context.delete(movie.favoritedBy[index])
}
}
to the view.
This does delete the favorite movie, but it also deletes the friend. My assumption is that the selected friend should then have no favorite movie rather than being deleted
There is an if in the Form that doesn't display the FAVORITED BY section if no friend has that movie as a favorite, but if I delete all the friends who had this movie as a favorite, the section remains (but is empty), until I exit the MovieDetail view and reload it
There is no answer for these exercises, so I could be doing it wrong.
EDIT: If I delete a movie using the app function to delete a movie, friends that have that movie as a favorite are not deleted and have their favorite movie set to None
I have an app that uses NSPersistentCloudKitContainer stored in a shared location via App Groups so my widget can fetch data to display. It works. But if you reset your iPhone and restore it from a backup, an error occurs:
The file "Name.sqlite" couldn't be opened. I suspect this happens because the widget is created before the app's data is restored. Restarting the iPhone is the only way to fix it though, opening the app and reloading timelines does not. Anything I can do to fix that to not require turning it off and on again?
I got a preview crash info as this:
xxx crashed due to fatalError in PersistentModel.swift at line 559.
This KeyPath does not appear to relate RecordInfo to anything - \RecordInfo.<computed 0x00000001921dfb4e (Array<SomeInfo>)>
If I change preview device to iPhoneSE, It is no crash.
I think the reason is I have some dirty data in iPhone16 Pro preview device.
If I'm right and how to delete it?
Model of RecordInfo like this:
@Model
class RecordInfo {
@Relationship(deleteRule: .cascade) var someInfo:[SomeInfo]
}
@Model
class SomeInfo {
var date: Date
var info: String
}
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 ?
Hi guys. Can someone please confirm this bug so I report it? The issue is that SwiftData relationships don't update the views in some specific situations on devices running iOS 18 Beta. One clear example is with CloudKit. I created a small example for testing. The following code creates two @models, one to store bands and another to store their records. The following code works with no issues. (You need to connect to a CloudKit container and test it on two devices)
import SwiftUI
import SwiftData
struct ContentView: View {
@Environment(\.modelContext) private var modelContext
@Query private var records: [Record]
var body: some View {
NavigationStack {
List(records) { record in
VStack(alignment: .leading) {
Text(record.title)
Text(record.band?.name ?? "Undefined")
}
}
.toolbar {
ToolbarItem {
Button("Add Record") {
let randomNumber = Int.random(in: 1...100)
let newBand = Band(name: "New Band \(randomNumber)", records: nil)
modelContext.insert(newBand)
let newRecord = Record(title: "New Record \(randomNumber)", band: newBand)
modelContext.insert(newRecord)
}
}
}
}
}
}
@Model
final class Record {
var title: String = ""
var band: Band?
init(title: String, band: Band?) {
self.title = title
self.band = band
}
}
@Model
final class Band {
var name: String = ""
var records: [Record]?
init(name: String, records: [Record]?) {
self.name = name
self.records = records
}
}
This view includes a button at the top to add a new record associated with a new band. The data appears on both devices, but if you include more views inside the List, the views on the second device are not updated to show the values of the relationships. For example, if you extract the row to a separate view, the second device shows the relationships as "Undefined". You can try the following code.
struct ContentView: View {
@Environment(\.modelContext) private var modelContext
@Query private var records: [Record]
var body: some View {
NavigationStack {
List {
ForEach(records) { record in
RecordRow(record: record)
}
}
.toolbar {
ToolbarItem {
Button("Add Record") {
let randomNumber = Int.random(in: 1...100)
let newBand = Band(name: "New Band \(randomNumber)", records: nil)
modelContext.insert(newBand)
let newRecord = Record(title: "New Record \(randomNumber)", band: newBand)
modelContext.insert(newRecord)
}
}
}
}
}
}
struct RecordRow: View {
let record: Record
var body: some View {
VStack(alignment: .leading) {
Text(record.title)
Text(record.band?.name ?? "Undefined")
}
}
}
Here I use a ForEach loop and move the row to a separate view. Now on the second device the relationships are nil, so the row shows the text "Undefined" instead of the name of the band.
I attached an image from my iPad. I inserted all the information on my iPhone. The first three rows were inserted with the first view. But the last two rows were inserted after I extracted the rows to a separate view. Here you can see that the relationships are nil and therefore shown as "Undefined". The views are not updated to show the real value of the relationship.
This example shows the issue with CloudKit, but this also happens locally in some situations. The system doesn't detect updates in relationships and therefore doesn't refresh the views.
Please, let me know if you can reproduce the issue. I'm using Mac Sequoia 15.1, and two devices with iOS 18.0.
Perhaps I just have the wrong expectations, but I discovered some odd behavior from SwiftData that sure seems like a bug to me...
If you make any change to any SwiftData model object — even just setting a property to its current value — every SwiftUI view that uses SwiftData is rebuilt. Every query and every entity reference, even if the property was set on a model class that is completely unrelated to the view.
SwiftUI does such a good job of optimizing UI updates that it's hard to notice the issue. I only noticed it because the updates were triggering my debug print statements.
To double-check this, I went back to Apple's new iOS app template — the one that is just a list of dated items — and added a little code to touch an unrelated record in the background:
@Model
class UnrelatedItem {
var name: String
init(name: String) {
self.name = name
}
}
@main
struct jumpyApp: App {
var sharedModelContainer: ModelContainer = {
let schema = Schema([
Item.self,
UnrelatedItem.self
])
let modelConfiguration = ModelConfiguration(schema: schema, isStoredInMemoryOnly: false)
do {
return try ModelContainer(for: schema, configurations: [modelConfiguration])
} catch {
fatalError("Could not create ModelContainer: \(error)")
}
}()
init() {
let context = sharedModelContainer.mainContext
// Create 3 items at launch so we immediately have some data to work with.
if try! context.fetchCount(FetchDescriptor<Item>()) == 0 {
for _ in 0..<3 {
let item = Item(timestamp: Date())
context.insert(item)
}
}
// Now create one unrelated item.
let unrelatedItem = UnrelatedItem(name: "Mongoose")
context.insert(unrelatedItem)
try? context.save()
// Set up a background task that updates the unrelated item every second.
Task {
while true {
try? await Task.sleep(nanoseconds: 1_000_000_000)
Task { @MainActor in
// We don't even have to change the name or save the contxt.
// Just setting the name to the same value will trigger a change.
unrelatedItem.name = "Mongoose"
}
}
}
}
var body: some Scene {
WindowGroup {
ContentView()
}
.modelContainer(sharedModelContainer)
}
}
I also added a print statement to the ContentView so I could see when the view updates.
struct ContentView: View {
@Environment(\.modelContext) private var modelContext
@Query private var items: [Item]
var body: some View {
NavigationSplitView {
List {
let _ = Self._printChanges()
...
The result is that the print statement logs 2 messages to the debug console every second. I checked in iOS 17, 18.1, and 18.2, and they all behave this way.
Is this the intended behavior? I thought the whole point of the new Observation framework in iOS 17 was to track which data had changed and only send change notifications to observers who were using that data.
Some users of my app are reporting total loss of data while using the app.
This is happening specifically when they enable iCloud sync.
I am doing following
private func setupContainer(enableICloud: Bool) {
container = NSPersistentCloudKitContainer(name: "")
container.viewContext.automaticallyMergesChangesFromParent = true
container.viewContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy
guard let description: NSPersistentStoreDescription = container.persistentStoreDescriptions.first else {
fatalError()
}
description.setOption(true as NSNumber, forKey: NSPersistentHistoryTrackingKey)
description.setOption(true as NSNumber, forKey: NSPersistentStoreRemoteChangeNotificationPostOptionKey)
if enableICloud == false {
description.cloudKitContainerOptions = nil
}
container.loadPersistentStores { description, error in
if let error {
// Handle error
}
}
}
When user clicks on Toggle to enable/disable iCloud sync I just set the description.cloudKitContainerOptions to nil and then user is asked to restart the app.
Apart from that I periodically run the clear history
func deleteTransactionHistory() {
let sevenDaysAgo = Calendar.current.date(byAdding: .day, value: -7, to: Date())!
let purgeHistoryRequest = NSPersistentHistoryChangeRequest.deleteHistory(before: sevenDaysAgo)
let backgroundContext = container.newBackgroundContext()
backgroundContext.performAndWait {
try! backgroundContext.execute(purgeHistoryRequest)
}
}
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 am running into some issues when trying to destroy CoreData persistentStores. When a user logs out of my app, I want to completely reset CoreData and delete any existing data. My code to reset CoreData looks like this:
let coordinator = self.persistentContainer.persistentStoreCoordinator
self.persistentContainer.viewContext.reset()
coordinator.persistentStores.forEach { store in
guard let url = store.url else { return }
do {
try coordinator.destroyPersistentStore(at: url, type: .sqlite)
_ = try coordinator.addPersistentStore(ofType: NSSQLiteStoreType, configurationName: nil, at: url)
} catch {
print(error)
}
}
However, my app is crashing with
Object 0xb2b5cc80445813de <x-coredata://BDB999D4-49A4-4CB3-AC3A-666AD60BEFC6/AccountEntity/p5> persistent store is not reachable from this NSManagedObjectContext's coordinator
It seems this is related to the SwiftUI @FetchRequest wrappers. If I do not open the views where I am using @FetchRequest, the logout goes smoothly. Otherwise, I get the crash above.
Has anyone run into anything similar? Is there something else I need to do to get the underlying FRC to release its references to those entities? I was under the impression that calling reset() on the managed object context would be enough to remove those items from memory and get the destroying of the persistent store to go smoothly.
Alternately, is there another/better way I should be destroying the DB?
Any advice or related observations would be greatly appreciated. Thank you!
I have used core data before via the model editor. This is the first time I'm using swift data and that too with CloudKit. Can you tell me if the following model classes are correct?
I have an expense which can have only one sub category which in turn belongs to a single category. Here are my classes...
// Expense.swift
// Pocket Expense Diary
//
// Created by Neerav Kothari on 16/05/25.
//
import Foundation
import SwiftData
@Model
class Expense {
@Attribute var expenseDate: Date? = nil
@Attribute var expenseAmount: Double? = nil
@Attribute var expenseCategory: Category? = nil
@Attribute var expenseSubCategory: SubCategory? = nil
var date: Date {
get {
return expenseDate ?? Date()
}
set {
expenseDate = newValue
}
}
var amount: Double{
get {
return expenseAmount ?? 0.0
}
set {
expenseAmount = newValue
}
}
var category: Category{
get {
return expenseCategory ?? Category.init(name: "", icon: "")
}
set {
expenseCategory = newValue
}
}
var subCategory: SubCategory{
get {
return expenseSubCategory ?? SubCategory.init(name: "", icon: "")
}
set {
expenseSubCategory = newValue
}
}
init(date: Date, amount: Double, category: Category, subCategory: SubCategory) {
self.date = date
self.amount = amount
self.category = category
self.subCategory = subCategory
}
}
//
// Category.swift
// Pocket Expense Diary
//
// Created by Neerav Kothari on 16/05/25.
//
import Foundation
import SwiftData
@Model
class Category {
@Attribute var categoryName: String? = nil
@Attribute var categoryIcon: String? = nil
var name: String {
get {
return categoryName ?? ""
}
set {
categoryName = newValue
}
}
var icon: String {
get {
return categoryIcon ?? ""
}
set {
categoryIcon = newValue
}
}
@Relationship(inverse: \Expense.expenseCategory) var expenses: [Expense]? = []
init(name: String, icon: String) {
self.name = name
self.icon = icon
}
}
// SubCategory.swift
// Pocket Expense Diary
//
// Created by Neerav Kothari on 16/05/25.
//
import Foundation
import SwiftData
@Model
class SubCategory {
@Attribute var subCategoryName: String? = nil
@Attribute var subCategoryIcon: String? = nil
var name: String {
get {
return subCategoryName ?? ""
}
set {
subCategoryName = newValue
}
}
var icon: String {
get {
return subCategoryIcon ?? ""
}
set {
subCategoryIcon = newValue
}
}
@Relationship(inverse: \Expense.expenseSubCategory) var expenses: [Expense]? = []
init(name: String, icon: String) {
self.name = name
self.icon = icon
}
}
The reason why I have wrappers is the let the existing code (before CloudKit was integrated), work.
In future versions I plan to query expenses even via category or sub category. I particularly doubt for the relationship i have set. should there be one from category to subcategory as well?
As of 2025-05-03, when a macOS user enables iCloud Drive synchronization for Desktop & Documents in US region, does iCloud filter xattrs upon upload or later when downloading back to another macOS host? Or is it the case that iCloud has no filtering of third-party xattrs? Where can I find the technical document outlining exactly what iCloud does with xattrs set on macOS host files and folders synchronized with iCloud Drive?
I'm running into an undocumented error coming back from CloudKit operations.
Specifically, I'm attempting to save new records via CKModifyRecordsOperation. I'm receiving this error for each of the records in the perRecordSaveBlock callback:
<CKError 0x3018ac3c0: "Internal Error" (1/3001); "MMCSEngineCreate failed">
Is anyone else facing this error? It has been happening for several days and I'm finally getting around to reproduction with the Console app and logs. I have 16 records on my device locally that each one gets this error back.
FB16547732 - CloudKit: CKModifyRecordsOperation saving new records results in Error <CKError 0x3018ac1e0: "Internal Error" (1/3001); "MMCSEngineCreate failed">
DESCRIPTION
I have an App use iCloud to save data.
The App had a CoreData ManagedObject 'Product', 'Product' Object had an attribute name 'count' and it is a Double Type.
I need to synchronises 'count' property across multiple devices.
for example:
I have a devices A、B.
A device set 'Product.count' = 100.
B device set 'Product.count' = 50.
I hope the 'Product.count' == 150 that results.
how to synchronises the 'Product.count' == 150 for multiple devices.
If I have more devices in future, How to get the latest 'Product.count' that it is correct result.
I have tried to set up iCloud sync. Despite fully isolating and resetting my development environment, the app fails with:
NSCocoaErrorDomain Code=134060 (PersistentStoreIncompatibleVersionHashError)
What I’ve done:
Created a brand new CloudKit container
Created a new bundle ID and app target
Renamed the Core Data model file itself
Set a new model version
Used a new .sqlite store path
Created a new .entitlements file with the correct container ID
Verified that the CloudKit dashboard shows no records
Deleted and reinstalled the app on a real device
Also tested with “Automatically manage signing” and without
Despite this, the error persists. I am very inexperienced and am not sure what my next step is to even attempt to fix this. Any guidance is apprecitated.
Swift recently added support for Int128. However, they do need NOT seem to be supported in SwiftData. Now totally possible I'm doing something wrong too.
I have the project set to macOS 15 to use a UInt128 in @Model class as attribute. I tried using a clean Xcode project with Swift Data choosen in the macOS app wizard.
Everything compiles, but it fails at runtime in both my app and "Xcode default" SwiftData:
SwiftData/SchemaProperty.swift:380: Fatal error: Unexpected property within Persisted Struct/Enum: Builtin.Int128
with the only modification to from stock is:
@Model
final class Item {
var timestamp: Date
var ipv6: UInt128
init(timestamp: Date) {
self.timestamp = timestamp
self.ipv6 = 0
}
}
I have tried both Int128 and UInt128. Both fails exactly the same. In fact, so exactly, when using UInt128 it still show a "Int128" in error message, despite class member being UInt128 .
My underlying need is to store an IPv6 addresses with an app, so the newer UInt128 would work to persist it. Since Network Framework IPv6Address is also not compatible, it seems, with SwiftData. So not a lot of good options, other an a String. But for an IPv6 address that suffers from that same address can take a few String forms (i.e. "0000:0000:0000:0000:0000:0000:0000:0000" =="0:0:0:0:0:0:0:0" == "::") which is more annoying than having a few expand Int128 as String separator ":".
Ideas welcomed. But potentially a bug in SwiftData since Int128 is both a Builtin and conforms to Codable, so from my reading it should work.