We are currently implementing a custom iCloud sync for our macOS and iOS apps using CloudKit. Syncing works fine as long as the number of record sends is relatively small.
But when we test with a large number of changes ( 80,000+ CKRecords ) we start running into problems.
Our sending strategy is very conservative to avoid rate limits:
We send records sequentially in batches of 250 records
With about 2 seconds pause between operations
Records are small and contain no assets (assets are uploaded separately)
At some point we start receiving:
“Database commit size exceeds limit”
After that, CloudKit begins returning rate-limit errors with retryAfter-Information in the error.
We wait for the retry time and try again, but from this moment on, nothing progresses anymore. Every subsequent attempt fails.
We could not find anything in the official documentation regarding such a “commit size” limit or what triggers this failure state.
So my questions are:
Are there undocumented limits on the total number of records that can exist in an iCloud database (private or shared)?
Is there a maximum volume of record modifications a container can accept within a certain timeframe, even if operations are split into small batches with pauses?
Is it possible that sending large numbers of records in a row can temporarily or permanently “stall” a CloudKit container?
Any insights or experiences would be greatly appreciated.
Thank you!
iCloud & Data
RSS for tagLearn how to integrate your app with iCloud and data frameworks for effective data storage
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I'm looking for guidance how to mitigate this crash. It seems super deep inside Core Data' FRC fetchedObjects management.
In my code, it's initiated by this
viewContext.perform {
[unowned self] in
self.viewContext.mergeChanges(fromContextDidSave: notification)
}
which is directly followed by the stack trace below.
Basically merging data from .NSManagedObjectContextDidSave notification from another NSManagedObjectContext. Nothing special, it works great for years, apart from these rare occurrences.
Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Exception Reason: -[__NSCFArray objectAtIndex:]: index (235) beyond bounds (234)
Termination Reason: SIGNAL 6 Abort trap: 6
Triggered by Thread: 0
Last Exception Backtrace:
0 CoreFoundation 0x199e947cc __exceptionPreprocess + 164 (NSException.m:249)
1 libobjc.A.dylib 0x1971672e4 objc_exception_throw + 88 (objc-exception.mm:356)
2 CoreFoundation 0x199fc4258 _NSArrayRaiseBoundException + 368 (NSCFArray.m:22)
3 CoreFoundation 0x199e288a4 -[__NSCFArray objectAtIndex:] + 200 (NSCFArray.m:42)
4 CoreData 0x1a1e17338 -[_PFMutableProxyArray objectAtIndex:] + 40 (_PFArray.m:1860)
5 CoreData 0x1a1e1673c -[NSFetchedResultsController _updateFetchedObjectsWithInsertChange:] + 380 (NSFetchedResultsController.m:1582)
6 CoreData 0x1a1e1426c __82-[NSFetchedResultsController(PrivateMethods) _core_managedObjectContextDidChange:]_block_invoke + 2240 (NSFetchedResultsController.m:2171)
7 CoreData 0x1a1dcdf80 developerSubmittedBlockToNSManagedObjectContextPerform + 156 (NSManagedObjectContext.m:4002)
8 CoreData 0x1a1e41a44 -[NSManagedObjectContext performBlockAndWait:] + 216 (NSManagedObjectContext.m:4113)
9 CoreData 0x1a1e41034 -[NSFetchedResultsController _core_managedObjectContextDidChange:] + 124 (NSFetchedResultsController.m:2379)
10 CoreFoundation 0x199e632f4 __CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__ + 148 (CFNotificationCenter.c:701)
11 CoreFoundation 0x199e63210 ___CFXRegistrationPost_block_invoke + 88 (CFNotificationCenter.c:194)
12 CoreFoundation 0x199e63158 _CFXRegistrationPost + 436 (CFNotificationCenter.c:222)
13 CoreFoundation 0x199e6170c _CFXNotificationPost + 728 (CFNotificationCenter.c:1248)
14 Foundation 0x198a84ea4 -[NSNotificationCenter postNotificationName:object:userInfo:] + 92 (NSNotification.m:531)
15 CoreData 0x1a1e11650 -[NSManagedObjectContext _createAndPostChangeNotification:deletions:updates:refreshes:deferrals:wasMerge:] + 1736 (NSManagedObjectContext.m:8098)
16 CoreData 0x1a1e10e0c -[NSManagedObjectContext _postRefreshedObjectsNotificationAndClearList] + 164 (NSManagedObjectContext.m:7631)
17 CoreData 0x1a1e0fad8 -[NSManagedObjectContext _processRecentChanges:] + 100 (NSManagedObjectContext.m:7714)
18 CoreData 0x1a1e3563c -[NSManagedObjectContext _coreMergeChangesFromDidSaveDictionary:usingObjectIDs:withClientQueryGeneration:] + 3436 (NSManagedObjectContext.m:3723)
19 CoreData 0x1a1e34350 __116+[NSManagedObjectContext(_NSCoreDataSPI) _mergeChangesFromRemoteContextSave:intoContexts:withClientQueryGeneration:]_block_invoke_4 + 76 (NSManagedObjectContext.m:9531)
20 CoreData 0x1a1dcdf80 developerSubmittedBlockToNSManagedObjectContextPerform + 156 (NSManagedObjectContext.m:4002)
21 CoreData 0x1a1e41a44 -[NSManagedObjectContext performBlockAndWait:] + 216 (NSManagedObjectContext.m:4113)
22 CoreData 0x1a1e39880 +[NSManagedObjectContext _mergeChangesFromRemoteContextSave:intoContexts:withClientQueryGeneration:] + 2372 (NSManagedObjectContext.m:9537)
23 CoreData 0x1a1e344a0 -[NSManagedObjectContext mergeChangesFromContextDidSaveNotification:] + 292 (NSManagedObjectContext.m:0)
Topic:
App & System Services
SubTopic:
iCloud & Data
it seems that is going to the appstore to find the app to execute the share but my app is not in the appstore yet. I am using a sandboxed user and a non sandboxed user, I have tried real phones connected to xcode and simulator same effect, looking for how to test my ckshare in testflight thanks
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?
In core-data I have a contact and location entity. I have one-to-many relationship from contact to locations and one-to-one from location to contact. I create contact in a seperate view and save it. Later I create a location, fetch the created contact, and save it while specifying the relationship between location and contact contact and test if it actually did it and it works.
viewContext.perform {
do {
// Set relationship using the generated accessor method
currentContact.addToLocations(location)
try viewContext.save()
print("Saved successfully. Locations count:", currentContact.locations?.count ?? 0)
if let locs = currentContact.locations {
print("📍 Contact has \(locs.count) locations.")
for loc in locs {
print("➡️ Location: \(String(describing: (loc as AnyObject).locationName ?? "Unnamed"))")
}
}
} catch {
print("Failed to save location: \(error.localizedDescription)")
}
}
In my NSManagedObject class properties I have this : for Contact:
@NSManaged public var locations: NSSet?
for Location:
@NSManaged public var contact: Contact?
in my persistenceController I have:
for desc in [publicStore, privateStore] {
desc.setOption(true as NSNumber, forKey:
NSPersistentStoreRemoteChangeNotificationPostOptionKey)
desc.setOption(true as NSNumber, forKey: NSPersistentHistoryTrackingKey)
desc.setOption(true as NSNumber, forKey: NSMigratePersistentStoresAutomaticallyOption)
desc.setOption(true as NSNumber, forKey: NSInferMappingModelAutomaticallyOption)
desc.setOption(true as NSNumber, forKey: "CKSyncCoreDataDebug") // Optional: Debug sync
// Add these critical options for relationship sync
desc.setOption(true as NSNumber, forKey: "NSPersistentStoreCloudKitEnforceRecordExistsKey")
desc.setOption(true as NSNumber, forKey: "NSPersistentStoreCloudKitMaintainReferentialIntegrityKey")
// Add this specific option to force schema update
desc.setOption(true as NSNumber, forKey: "NSPersistentStoreRemoteStoreUseCloudKitSchemaKey")
}
When synchronization happens on CloudKit side, it creates CKRecords: CD_Contact and CD_Location. However for CD_Location it creates the relationship CD_contact as a string and references the CD_Contact. This I thought should have come as REFERENCE On the CD_Contact there is no CD_locations field at all. I do see the relationships being printed on coredata side but it does not come as REFERENCE on cloudkit. Spent over a day on this. Is this normal, what am I doing wrong here? Can someone advise?
I have not had any successful Schema Migration with CloudKit so far so I'm trying to do with with just very basic attributes, with multiple Versioned Schemas
This is the code in my App Main
var sharedModelContainer: ModelContainer = {
let schema = Schema(versionedSchema: AppSchemaV4.self)
do {
return try ModelContainer(
for: schema,
migrationPlan: AppMigrationPlan.self,
configurations: ModelConfiguration(cloudKitDatabase: .automatic))
} catch {
fatalError("Could not create ModelContainer: \(error)")
}
}()
var body: some Scene {
WindowGroup {
ItemListView()
}
.modelContainer(sharedModelContainer)
}
And this is the code for my MigrationPlan and VersionedSchemas.
typealias Item = AppSchemaV4.Item3
enum AppMigrationPlan: SchemaMigrationPlan {
static var schemas: [any VersionedSchema.Type] {
[AppSchemaV1.self, AppSchemaV2.self, AppSchemaV3.self, AppSchemaV4.self]
}
static var stages: [MigrationStage] {
[migrateV1toV2, migrateV2toV3, migrateV3toV4]
}
static let migrateV1toV2 = MigrationStage.lightweight(
fromVersion: AppSchemaV1.self,
toVersion: AppSchemaV2.self
)
static let migrateV2toV3 = MigrationStage.lightweight(
fromVersion: AppSchemaV2.self,
toVersion: AppSchemaV3.self
)
static let migrateV3toV4 = MigrationStage.custom(
fromVersion: AppSchemaV3.self,
toVersion: AppSchemaV4.self,
willMigrate: nil,
didMigrate: { context in
// Fetch all Item1 instances
let item1Descriptor = FetchDescriptor<AppSchemaV3.Item1>()
let items1 = try context.fetch(item1Descriptor)
// Fetch all Item2 instances
let item2Descriptor = FetchDescriptor<AppSchemaV3.Item2>()
let items2 = try context.fetch(item2Descriptor)
// Convert Item1 to Item3
for item in items1 {
let newItem = AppSchemaV4.Item3(name: item.name, text: "Migrated from Item1 on \(item.date)")
context.insert(newItem)
}
// Convert Item2 to Item3
for item in items2 {
let newItem = AppSchemaV4.Item3(name: item.name, text: "Migrated from Item2 with value \(item.value)")
context.insert(newItem)
}
try? context.save()
}
)
}
enum AppSchemaV1: VersionedSchema {
static var versionIdentifier: Schema.Version = Schema.Version(1, 0, 0)
static var models: [any PersistentModel.Type] {
[Item1.self]
}
@Model class Item1 {
var name: String = ""
init(name: String) {
self.name = name
}
}
}
enum AppSchemaV2: VersionedSchema {
static var versionIdentifier: Schema.Version = Schema.Version(2, 0, 0)
static var models: [any PersistentModel.Type] {
[Item1.self]
}
@Model class Item1 {
var name: String = ""
var date: Date = Date()
init(name: String) {
self.name = name
self.date = Date()
}
}
}
enum AppSchemaV3: VersionedSchema {
static var versionIdentifier: Schema.Version = Schema.Version(3, 0, 0)
static var models: [any PersistentModel.Type] {
[Item1.self, Item2.self]
}
@Model class Item1 {
var name: String = ""
var date: Date = Date()
init(name: String) {
self.name = name
self.date = Date()
}
}
@Model class Item2 {
var name: String = ""
var value: Int = 0
init(name: String, value: Int) {
self.name = name
self.value = value
}
}
}
enum AppSchemaV4: VersionedSchema {
static var versionIdentifier: Schema.Version = Schema.Version(4, 0, 0)
static var models: [any PersistentModel.Type] {
[Item1.self, Item2.self, Item3.self]
}
@Model class Item1 {
var name: String = ""
var date: Date = Date()
init(name: String) {
self.name = name
self.date = Date()
}
}
@Model class Item2 {
var name: String = ""
var value: Int = 0
init(name: String, value: Int) {
self.name = name
self.value = value
}
}
@Model class Item3 {
var name: String = ""
var text: String = ""
init(name: String, text: String) {
self.name = name
self.text = text
}
}
}
My experiment was:
To create Items for every version of the schema
Updating the typealias along the way to reflect the latest Item version.
Updating the Schema in my ModelContainer to reflect the latest Schema Version.
By AppSchemaV4, I have expected all my Items to be displayed/migrated to Item3, but it does not seem to be the case.
I can only see newly created Item3 records.
My question is, is there something wrong with how I'm doing the migrations? or are migrations not really working with CloudKit right now?
I built a SwiftData App that relies on CloudKit to synchronize data across devices.
That means all model relationships must be expressed as Optional.
That’s fine, but there is a limitation in using Optional’s in SwiftData SortDescriptors (Crashes App)
That means I can’t apply a SortDescriptor to ModelA using some property value in ModelB (even if ModelB must exist)
I tried using a computed property in ModelA that referred to the property in ModelB, BUT THIS DOESN”T WORK EITHER!
Am I stuck storing redundant data In ModelA just to sort ModelA as I would like???
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).
If an app is using top-level models, meaning they exist outside the VersionedSchema enum, is it safe to keep them outside of the VersionedSchema enum and use a migration plan for simple migrations. Moving the models within the VersionedSchema enum I believe would change the identity of the models and result in data being lost, although correct me if I'm wrong in that statement.
The need presently is just to add another variable to the model and then set that variable within the init function:
var updateId = UUID()
The app is presently in TestFlight although I'd like to preserve data for users that are currently using the app.
The data within SwiftData is synchronized with CloudKit and so I'd also like to avoid any impact to synchronization.
Any thoughts on this would be greatly appreciated.
I’m trying to build a CRUD app using SwiftData, @Query model and multidatepicker.
The data from a multidatepicker is stored or persists in SwiftData as Set = [].
My current dilemma is how to use SwiftData and @Query model Predicate to find all records on the current date.
I can’t find any SwiftData documentation or examples @Query using Set = [].
My CRUD app should retrieve all records for the current date. Unfortunately, I don’t know the correct @Query model syntax for Set = [].
Hello,
In my iOS/SwiftUI/SwiftData app, I want the user to be able to hit [Cancel] from editing in a detail screen and return to the previous screen without changes being saved.
I believed that setting autosaveEnabled to false and/or calling .rollback would prevent changes from being saved, unless/until I call .save() when the user clicks [Save], but this does not seem to be correct.
I set modelContext.autosaveEnabled = false and I call modelContext.rollback() when the user hits [Cancel], but any changes they made are not rolled back, but saved even if I don’t call save().
I have tried setting autosaveEnabled to false when I create the ModelContainer on a @MainActor function when the App starts, and in the detail/edit screen’s .onAppear(). I can see that .rollback is being called when the [Cancel] button is tapped. In all cases, any changes the user made before hitting [Cancel] are saved.
The Developer Documentation on autosaveEnabled includes this:
“The default value is false. SwiftData automatically sets this property to true for the model container’s mainContext."
I am working on the mainContext, but it appears that setting autosaveEnabled to false has no effect no matter where in the code I set it.
If someone sees what I am doing wrong, I’d sure appreciate the input. If this description doesn’t explain the problem well enough, I’ll develop a minimal focused example.
I have a SwiftData model where I need to customize behavior based on the value of a property (connectorType). Here’s a simplified version of my model:
@Model
public final class ConnectorModel {
public var connectorType: String
...
func doSomethingDifferentForEveryConnectorType() {
...
}
}
I’d like to implement doSomethingDifferentForEveryConnectorType in a way that allows the behavior to vary depending on connectorType, and I want to follow best practices for scalability and maintainability. I’ve come up with three potential solutions, each with pros and cons, and I’d love to hear your thoughts on which one makes the most sense or if there’s a better approach:
**Option 1: Use switch Statements
**
func doSomethingDifferentForEveryConnectorType() {
switch connectorType {
case "HTTP":
// HTTP-specific logic
case "WebSocket":
// WebSocket-specific logic
default:
// Fallback logic
}
}
Pros: Simple to implement and keeps the SwiftData model observable by SwiftUI without any additional wrapping.
Cons: If more behaviors or methods are added, the code could become messy and harder to maintain.
**Option 2: Use a Wrapper with Inheritance around swiftdata model
**
@Observable
class ParentConnector {
var connectorModel: ConnectorModel
init(connectorModel: ConnectorModel) {
self.connectorModel = connectorModel
}
func doSomethingDifferentForEveryConnectorType() {
fatalError("Not implemented")
}
}
@Observable
class HTTPConnector: ParentConnector {
override func doSomethingDifferentForEveryConnectorType() {
// HTTP-specific logic
}
}
Pros: Logic for each connector type is cleanly organized in subclasses, making it easy to extend and maintain.
Cons: Requires introducing additional observable classes, which could add unnecessary complexity.
**Option 3: Use a @Transient class that customizes behavior
**
protocol ConnectorProtocol {
func doSomethingDifferentForEveryConnectorType(connectorModel: ConnectorModel)
}
class HTTPConnectorImplementation: ConnectorProtocol {
func doSomethingDifferentForEveryConnectorType(connectorModel: ConnectorModel) {
// HTTP-specific logic
}
}
Then add this to the model:
@Model
public final class ConnectorModel {
public var connectorType: String
@Transient
public var connectorImplementation: ConnectorProtocol?
// Or alternatively from swiftui I could call myModel.connectorImplementation.doSomethingDifferentForEveryConnectorType() to avoid this wrapper
func doSomethingDifferentForEveryConnectorType() {
connectorImplementation?.doSomethingDifferentForEveryConnectorType(connectorModel: self)
}
}
Pros: Decouples model logic from connector-specific behavior. Avoids creating additional observable classes and allows for easy extension.
Cons: Requires explicitly passing the model to the protocol implementation, and setup for determining the correct implementation needs to be handled elsewhere.
My Questions
Which approach aligns best with SwiftData and SwiftUI best practices, especially for scalable and maintainable apps?
Are there better alternatives that I haven’t considered?
If Option 3 (protocol with dependency injection) is preferred, what’s the best way to a)manage the transient property 2) set the correct implementation and 3) pass reference to swiftdata model?
Thanks in advance for your advice!
I am trying to save to cloud kit shared database. The shared database does not allow zones to be set up.
How do I save to sharedCloudDatabase without a zone?
private func addItem(recordType: String, name: String) {
let record = CKRecord(recordType: recordType)
record[Constances.field.name] = name as CKRecordValue
record[Constances.field.done] = false as CKRecordValue
record[Constances.field.priority] = 0 as CKRecordValue
CKContainer.default().sharedCloudDatabase.save(record) { [weak self] returnRecord, error in
if let error = error {
print("Error saving record: \(record[Constances.field.name] as? String ?? "No Name"): \n \(error)")
return
}
}
}
The following error message prints out:
Error saving record: Milk:
<CKError 0x15af87900: "Server Rejected Request" (15/2027); server message = "Default zone is not accessible in shared DB"; op = B085F7BA703D4A08; uuid = 87AEFB09-4386-4E43-81D7-971AAE8BA9E0; container ID = "iCloud.com.sfw-consulting.Family-List">
The NSMetadataUbiquitousItemDownloadingStatusKey indicates the status of a ubiquitous (iCloud Drive) file.
A key value of NSMetadataUbiquitousItemDownloadingStatusDownloaded is defined as indicating there is a local version of this file available. The most current version will get downloaded as soon as possible .
However this no longer occurs since iOS 18.4. A ubiquitous file may remain in the NSMetadataUbiquitousItemDownloadingStatusDownloaded state for an indefinite period.
There is a workaround: call [NSFileManager startDownloadingUbiquitousItemAtURL: error:] however this shouldn't be necessary, and introduces delays over the previous behaviour.
Has anyone else seen this behaviour? Is this a permanent change?
FB17662379
We have an unreleased SwiftData app for iOS18+. While we were testing I saw reports on the forum about unexpected database migrations for codable arrays on iOS26.1.
I'd like to ask a couple of questions:
1- Does this issue originate from the new Xcode version, or is it specific to iOS 26.1?
2- Is it possible to change our attribute so that users on older iOS versions receive the same model, preventing a migration from being triggered when they upgrade to iOS 26.1?
One of our models looks like this:
struct Point: Codable, Hashable {
let x: Int
let y: Int
}
@Model
class Grid {
private(set) var gridId: String = ""
var points: [Point] = []
var updatedAt: Date = Date()
private(set) var createdAt: Date = Date()
#Index<Grid>([\.gridId])
...
}
I can think of some options like:
// 1
@Attribute(.transformable(by: CustomJsonTransformer.self)) var points: [Point] = []
// 2
@Attribute(.externalStorage) var points: [Point] = []
// 3
var points: Data = Data() // store points as data
However, I'm not sure which one to use.
What would you recommend to handle this, or is there a better strategy you would suggest?
Hey,
For some reason I see crashes for my iOS app related to CloudKit entitlements.
The crash happens on start up and it says:
"CKException - Application has malformed entitlements. Found value "*" for entitlement com.apple.developer.icloud-services, expected an array of strings"
I have checked my entitlements of the same build on App Store Connect and it shows "com.apple.developer.icloud-services: ( "CloudKit" )"
So I am not sure why users are having this issue. I haven't been able to reproduce it.
Does anyone have any idea why this is happening?
Thanks
I'm writing some tests to confirm the behavior of my app. White creating a model actor to delete objects I realized that ModelContext.model(for:) does return objects that are deleted. I was able to reproduces this with this minimal test case:
@Model class Activity {
init() {}
}
struct MyLibraryTests {
let modelContainer = try! ModelContainer(
for: Activity.self,
configurations: ModelConfiguration(
isStoredInMemoryOnly: true
)
)
init() throws {
let context = ModelContext(modelContainer)
context.insert(Activity())
try context.save()
}
@Test func modelForIdAfterDelete() async throws {
let context = ModelContext(modelContainer)
let id = try context.fetch(FetchDescriptor<Activity>()).first!.id
context.delete(context.model(for: id) as! Activity)
try context.save()
let result = context.model(for: id) as? Activity
#expect(result == nil) // Expectation failed: (result → MyLibrary.Activity) == nil
}
@Test func fetchDescriptorAfterDelete() async throws {
let context = ModelContext(modelContainer)
let id = try context.fetch(FetchDescriptor<Activity>()).first!.id
context.delete(context.model(for: id) as! Activity)
try context.save()
let result = try context.fetch(
FetchDescriptor<Activity>(predicate: #Predicate { $0.id == id })
).first
#expect(result == nil)
}
}
Here I create a new context, insert an model and save it.
The test modelForIdAfterDelete does fail, as result still contains the deleted object.
I also tried to check #expect(result!.isDeleted), but it is also false.
With the second test I use a FetchDescriptor to retrieve the object by ID and it correctly returns nil.
Shouldn't both methods use a consistent behavior?
I have a simple model that contains a one-to-many relationship to itself to represent a simple tree structure. It is set to cascade deletes so deleting the parent node deletes the children.
Unfortunately I get an error when I try to batch delete. A test demonstrates:
@Model final class TreeNode {
var parent: TreeNode?
@Relationship(deleteRule: .cascade, inverse: \TreeNode.parent)
var children: [TreeNode] = []
init(parent: TreeNode? = nil) {
self.parent = parent
}
}
func testBatchDelete() throws {
let config = ModelConfiguration(isStoredInMemoryOnly: true)
let container = try ModelContainer(for: TreeNode.self, configurations: config)
let context = ModelContext(container)
context.autosaveEnabled = false
let root = TreeNode()
context.insert(root)
for _ in 0..<10 {
let child = TreeNode(parent: root)
context.insert(child)
}
try context.save()
// fails if first item doesn't have a nil parent, succeeds otherwise
// which row is first is random, so will succeed sometimes
try context.delete(model: TreeNode.self)
}
The error raised is:
CoreData: error: Unhandled opt lock error from executeBatchDeleteRequest Constraint trigger violation: Batch delete failed due to mandatory OTO nullify inverse on TreeNode/parent and userInfo {
NSExceptionOmitCallstacks = 1;
NSLocalizedFailureReason = "Constraint trigger violation: Batch delete failed due to mandatory OTO nullify inverse on TreeNode/parent";
"_NSCoreDataOptimisticLockingFailureConflictsKey" = ( );
}
Interestingly, if the first record when doing an unsorted query happens to be the parent node, it works correctly, so the above unit test will actually work sometimes.
Now, this can be "solved" by changing the reverse relationship to an optional like so:
@Relationship(deleteRule: .cascade, inverse: \TreeNode.parent)
var children: [TreeNode]?
The above delete will work fine. However, this causes issues with predicates that test counts in children, like for instance deleting only nodes where children is empty for example:
try context.delete(model: TreeNode.self,
where: #Predicate { $0.children?.isEmpty ?? true })
It ends up crashing and dumps a stacktrace to the console with:
An uncaught exception was raised
Keypath containing KVC aggregate where there shouldn't be one; failed to handle children.@count
(the stacktrace is quite long and deep in CoreData's NSSQLGenerator)
Does anyone know how to work around this?
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?
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?