Since running on iOS 14b1, I'm getting this in my log (I have Core Data logging enabled):
error: Store opened without NSPersistentHistoryTrackingKey but previously had been opened with NSPersistentHistoryTrackingKey - Forcing into Read Only mode store at 'file:///private/var/mobile/Containers/Shared/AppGroup/415B75A6-92C3-45FE-BE13-7D48D35909AF/StoreFile.sqlite'
As far as I can tell, it's impossible to open my store without that key set - it's in the init() of my NSPersistentContainer subclass, before anyone calls it to load stores.
Any ideas?
iCloud & Data
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I'm working on a macOS app with a Safari web extension. I'm trying to share a SwiftData model between devices using CloudKit synchronization. I am able to get synchronization in the main app on the same device, CloudKit sync works correctly — changes appear in the CloudKit Dashboard under com.apple.coredata.cloudkit.zone.
However, in the Safari App Extension, data is saved locally and persists across launches, but never syncs to CloudKit.
I have followed the recommended practices for configuring the App Group and entitlements, but the issue persists.
Questions:
Is there an official limitation preventing Safari App Extensions from connecting to the CloudKit daemon (cloudd)?
If not, what entitlements or configuration changes are required for a Safari App Extension to successfully sync with CloudKit?
Is the xpc_error=159 from bootstrap_look_up() a known sandbox restriction for this extension type?
Any guidance from Apple engineers or others who have successfully used CloudKit from a Safari App Extension would be appreciated.
What I’ve confirmed:
The extension’s .entitlements includes:
com.apple.security.app-sandbox
com.apple.developer.icloud-services
CloudKit
com.apple.developer.icloud-container-identifiers
iCloud.dev.example.myapp
Same iCloud container ID for both app and extension
CloudKit container exists and is initialized in CloudKit Console
Running in :Sandbox environment during development
Database name in SwiftData matches container identifier (without the iCloud. prefix)
The extension’s codesign output shows correct entitlements
App Group is configured (although in this case, extension and app use separate stores intentionally)
Observed behavior in Console.app logs:
CloudKit sync engine initializes in the extension
XPC activities are registered for import/export:
_xpc_activity_register: com.apple.coredata.cloudkit.activity.export.
xpc_activity_set_criteria: ... import.
Then a bootstrap lookup fails:
failed to do a bootstrap look-up: xpc_error=[159: Unknown error: 159]
CloudKit daemon connection error:
CKErrorDomain Code=6 "Error connecting to CloudKit daemon"
NSCocoaErrorDomain Code=4099
There is no “Will attempt to upload transactions” or “Upload succeeded” logs are ever seen.
Symptoms
When the extension is run, I see logs like the following in Console.app:
[0x13e215820] failed to do a bootstrap look-up: xpc_error=[159: Unknown error: 159]
CoreData+CloudKit: -[PFCloudKitSetupAssistant _checkAccountStatus:]_block_invoke(342): Fetched account info for store : (null)
Error Domain=CKErrorDomain Code=6 "Error connecting to CloudKit daemon. This could happen for many reasons..."
I'm running a project with these settings:
Default Actor Isolation: MainActor
Approachable Concurrency: Yes
Strict Concurrency Checking: Complete (this issue does not appear on the other two modes)
I receive a warning for this very simple use case. Can I actually fix anything about this or is this a case of Core Data not being entirely ready for this?
In reference to this, there was a workaround listed in the release notes of iOS 26 beta 5 (https://forums.swift.org/t/defaultisolation-mainactor-and-core-data-background-tasks/80569/22). Does this still apply as the only fix for this?
This is a simplified sample meant to run on a background context. The issue obviously goes away if this function would just run on the MainActor, then I can remove the perform block entirely.
class DataHandler {
func createItem() async {
let context = ...
await context.perform {
let newGame = Item(context: context)
/// Main actor-isolated property 'timestamp' can not be mutated from a Sendable closure
newGame.timestamp = Date.now
// ...
}
}
}
The complete use case would be more like this:
nonisolated
struct DataHandler {
@concurrent
func saveItem() async throws {
let context = await PersistenceController.shared.container.newBackgroundContext()
try await context.perform {
let newGame = Item(context: context)
newGame.timestamp = Date.now
try context.save()
}
}
}
I am working on a software where we want to add the feature to share the whole database with the other user. Database is iCloud combined with coredata. The other user(s) should be able to edit /delete and even create new objects in the share.
I did this with this code witch directly from sample code
let participants = try await ckConainer.fetchParticipants(matching: [lookupInfo], into: selectedStore)
for participant in participants {
participant.permission = .readWrite
participant.role = .privateUser
share.addParticipant(participant)
}
try await ckConainer.persistUpdatedShare(share, in: selectedStore)
the other user gets invited and I can see this in iCloud database that the other user is invited with status invited.
but the other user never gets a mail or something to accept and join the share. How does the other needs to accept the invitation ?
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?
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
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.
Using SwiftData and this is the simplest example I could boil down:
@Model
final class Item {
var timestamp: Date
var tag: Tag?
init(timestamp: Date) {
self.timestamp = timestamp
}
}
@Model
final class Tag {
var timestamp: Date
init(timestamp: Date) {
self.timestamp = timestamp
}
}
Notice Tag has no reference to Item.
So if I create a bunch of items and set their Tag. Later on I add the ability to delete a Tag. Since I haven't added inverse relationship Item now references a tag that no longer exists so so I get these types of errors:
SwiftData/BackingData.swift:875: Fatal error: This model instance was invalidated because its backing data could no longer be found the store. PersistentIdentifier(id: SwiftData.PersistentIdentifier.ID(url: x-coredata://EEC1D410-F87E-4F1F-B82D-8F2153A0B23C/Tag/p1), implementation: SwiftData.PersistentIdentifierImplementation)
I think I understand now that I just need to add the item reference to Tag and SwiftData will nullify all Item references to that tag when a Tag is deleted.
But, the damage is already done. How can I iterate through all Items that referenced a deleted tag and set them to nil or to a placeholder Tag? Or how can I catch that error and fix it when it comes up?
The crash doesn't occur when loading an Item, only when accessing item.tag?.timestamp, in fact, item.tag?.id is still ok and doesn't crash since it doesn't have to load the backing data.
I've tried things like just looping through all items and setting tag to nil, but saving the model context fails because somewhere in there it still tries to validate the old value.
Thanks!
It takes a few seconds, sometimes a few minutes for records to be downloaded back from CloudKit when the user reinstalls the app, which leads users to thinking their data was lost. I would like to know if there’s any way to provide a visual feedback about the current CloudKit sync status so I can let users know their data is being in fact downloaded back to their devices.
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 want to get to a point where I can use a small view with a query for my SwiftData model like this:
@Query
private var currentTrainingCycle: [TrainingCycle]
init(/*currentDate: Date*/) {
_currentTrainingCycle = Query(filter: #Predicate<TrainingCycle> {
$0.numberOfDays > 0
// $0.startDate < currentDate && currentDate < $0.endDate
}, sort: \.startDate)
}
The commented code is where I want to go. In this instance, it'd be created as a lazy var in a viewModel to have it stable (and not constantly re-creating the view). Since it was not working, I thought I could check the same view with a query that does not require any dynamic input. In this case, the numberOfDays never changes after instantiation.
But still, each time the app tries to create this view, the app becomes unresponsive, the CPU usage goes at 196%, memory goes way high and the device heats up quickly.
Am I holding it wrong? How can I have a dynamic predicate on a View in SwiftUI with SwiftData?
I am using SwiftData with CloudKit to synchronize data across multiple devices, and I have encountered an issue: occasionally, abnormal sync behavior occurs between two devices (it does not happen 100% of the time—only some users have reported this problem). It seems as if synchronization between the two devices completely stops; no matter what operations are performed on one end, the other end shows no response.
After investigating, I suspect the issue might be caused by both devices simultaneously modifying the same field, which could lead to CloudKit's logic being unable to handle such conflicts and causing the sync to stall. Are there any methods to avoid or resolve this situation?
Of course, I’m not entirely sure if this is the root cause. Has anyone encountered a similar issue?
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.
Hello 👋,
I encounter the "This model instance was invalidated because its backing data could no longer be found the store" crash with SwiftData. Which from what I understood means I try to access a model after it has been removed from the store (makes sense).
I made a quick sample to reproduce/better understand because there some case(s) I can't figure it out.
Let's take a concrete example, we have Home model and a Home can have many Room(s).
// Sample code
@MainActor
let foo = Foo() // A single reference
let database = Database(modelContainer: sharedModelContainer) // A single reference
@MainActor
class Foo {
// Properties to explicilty keep reference of model(s) for the purpose of the POC
var _homes = [Home]()
var _rooms = [Room]()
func fetch() async {
let homes = await database.fetch().map {
sharedModelContainer.mainContext.model(for: $0) as! Home
}
print(ObjectIdentifier(homes[0]), homes[0].rooms?.map(\.id)) // This will crash here or not.
}
// Same version of a delete function with subtle changes.
// Depending on the one you use calling delete then fetch will result in a crash or not.
// Keep a reference to only homes == NO CRASH
func deleteV1() async {
self._homes = await database.fetch().map {
sharedModelContainer.mainContext.model(for: $0) as! Home
}
await database.delete()
}
// Keep a reference to only rooms == NO CRASH
func deleteV2() async {
self._rooms = await database.fetch().map {
sharedModelContainer.mainContext.model(for: $0) as! Home
}[0].rooms ?? []
await database.delete()
}
// Keep a reference to homes & rooms == CRASH 💥
func deleteV3() async {
self._homes = await database.fetch().map {
sharedModelContainer.mainContext.model(for: $0) as! Home
}
self._rooms = _homes[0].rooms ?? []
// or even only retain reference to rooms that have NOT been deleted 🤔 like here "id: 2" make it crash
// self._rooms = _homes[0].rooms?.filter { r in r.id == "2" } ?? []
await database.delete()
}
}
Calling deleteV() then fetch() will result in a crash or not depending on the scenario.
I guess I understand deleteV1, deleteV2. In those case an unsaved model is served by the model(for:) API and accessing properties later on will resolve correctly. The doc says: "The identified persistent model, if known to the context; otherwise, an unsaved model with its persistentModelID property set to persistentModelID."
But I'm not sure about deleteV3. It seems the ModelContext is kind of "aware" there is still cyclic reference between my models that are retained in my code so it will serve these instances instead when calling model(for:) API ? I see my home still have 4 rooms (instead of 2). So I then try to access rooms that are deleted and it crash. Why of that ? I mean why not returning home with two room like in deleteV1 ?
Because SwiftData heavily rely on CoreData may be I miss a very simple thing here. If someone read this and have a clue for me I would be extremely graceful.
PS:
If someone wants to run it on his machine here's some helpful code:
// Database
let sharedModelContainer: ModelContainer = {
let schema = Schema([
Home.self,
Room.self,
])
let modelConfiguration = ModelConfiguration(schema: schema, isStoredInMemoryOnly: false)
debugPrint(modelConfiguration.url.absoluteString.replacing("%20", with: "\\ "))
return try! ModelContainer(for: schema, configurations: [modelConfiguration])
}()
extension Database {
static let shared = Database(modelContainer: sharedModelContainer)
}
@ModelActor
actor Database {
func insert() async {
let r1 = Room(id: "1", name: "R1")
let r2 = Room(id: "2", name: "R2")
let r3 = Room(id: "3", name: "R3")
let r4 = Room(id: "4", name: "R4")
let home = Home(id: "1", name: "My Home")
home.rooms = [r1, r2, r3, r4]
modelContext.insert(home)
try! modelContext.save()
}
func fetch() async -> [PersistentIdentifier] {
try! modelContext.fetchIdentifiers(FetchDescriptor<Home>())
}
@MainActor
func delete() async {
let mainContext = sharedModelContainer.mainContext
try! mainContext.delete(
model: Room.self,
where: #Predicate { r in
r.id == "1" || r.id == "4"
}
)
try! mainContext.save()
// 🤔 Calling fetch here seems to solve crash too, force home relationship to be rebuild correctly ?
// let _ = try! sharedModelContainer.mainContext.fetch(FetchDescriptor<Home>())
}
}
// Models
@Model
class Home: Identifiable {
@Attribute(.unique) public var id: String
var name: String
@Relationship(deleteRule: .cascade, inverse: \Room.home)
var rooms: [Room]?
init(id: String, name: String, rooms: [Room]? = nil) {
self.id = id
self.name = name
self.rooms = rooms
}
}
@Model
class Room: Identifiable {
@Attribute(.unique) public var id: String
var name: String
var home: Home?
init(id: String, name: String, home: Home? = nil) {
self.id = id
self.name = name
self.home = home
}
}
Hi All,
I work on a cross platform app, iOS/macOS.
All devises on iOS could synchronize data from Coredata : I create a client, I see him an all iOS devices.
But when I test on macOs (with TestFlight) the Mac app could not get any information from iOs devices.
On Mac, cloud drive is working because I could download and upload documents and share it between all devices, so the account is working but with my App on MacOS, there is no synchronisation.
idea????
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 am creating (or trying to) my first app using SwiftData - and I have questions :-)
The main question I can't get my head wrapped around is the following:
Let's say I have the sample below...
@Model
class Person {
@Relationship(inverse:\Hat.owner) var hat:Hat
}
@Model
class Hat {
var owner:Person?
}
It looks like I am creating a strong reference cycle between the person and the hat objects? And in fact I am seeing these kinds of reference cycles when I look at the memory debugger.
Many code samples I have seen so far use this type of relationship declaration...
And I am wondering: Am I missing something?
Admittedly I don't find many discussions about memory leaks caused by SwiftData despite the syntax being used in many examples?
So what is the situation? Did Apple just miss to explain that the inverse: declaration causes memory leaks or is there some kind of magic that I should understand?
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've run into a strange issue.
If a sheet loads a view that has a SwiftData @Query, and there is an if statement in the view body, I get the following error when running an iOS targetted SwiftUI app under MacOS 26.1:
Set a .modelContext in view's environment to use Query
While the view actually ends up loading the correct data, before it does, it ends up re-creating the sqlite store (opening as /dev/null).
The strange thing is that this only happens if there is an if statement in the body. The statement need not ever evaluate true, but it causes the issue.
Here's an example. It's based on the default xcode new iOS project w/ SwiftData:
struct ContentView: View {
@State private var isShowingSheet = false
var body: some View {
Button(action: { isShowingSheet.toggle() }) {
Text("Show Sheet")
}
.sheet(isPresented: $isShowingSheet, onDismiss: didDismiss) {
VStack {
ContentSheetView()
}
}
}
func didDismiss() { }
}
struct ContentSheetView: View {
@Environment(\.modelContext) private var modelContext
@Query public var items: [Item]
@State var fault: Bool = false
var body: some View {
VStack {
if fault { Text("Fault!") }
Button(action: addItem) {
Label("Add Item", systemImage: "plus")
}
List {
ForEach(items) { item in
Text(item.timestamp, format: Date.FormatStyle(date: .numeric, time: .standard))
}
}
}
}
private func addItem() {
withAnimation {
let newItem = Item(timestamp: Date())
modelContext.insert(newItem)
}
}
}
It requires some data to be added to trigger, but after adding it and dismissing the sheet, opening up the sheet with trigger the Set a .modelContext in view's environment to use Query. Flipping on -com.apple.CoreData.SQLDebug 1 will show it trying to recreate the database.
If you remove the if fault { Text("Fault!") } line, it goes away. It also doesn't appear to happen on iPhones or in the iPhone simulator.
Explicitly passing modelContext to the ContentSheetView like ContentSheetView().modelContext(modelContext) also seems to fix it.
Is this behavior expected?
I am developing an Xcode app with a job feed, with profile view, with chat eg. I fetch using federatet queries to my microservices thru Apollo Router. Infront of the Apollo Router i Have a Kong that adds a X user ID, that the microservices use for personalized feed and other user info. The info is stored with SwiftData. My thought is that i should add a better way of controlling when i need to fetch. I have a “lastupdateAPI” with different entities (profile, profile picture eg). So when nothing has changed we do not fetch. But rather then using a own API for this, isnt ETag better? Or is it any other recommendations with Xcode Swiftui. Good strategies for not fetching what i already have?