I am trying out the new AttributedString binding with SwiftUI’s TextEditor in iOS26. I need to save this to a Core Data database. Core Data has no AttributedString type, so I set the type of the field to “Transformable”, give it a custom class of NSAttributedString, and set the transformer to NSSecureUnarchiveFromData When I try to save, I first convert the Swift AttributedString to NSAttributedString, and then save the context. Unfortunately I get this error when saving the context, and the save isn't persisted: CoreData: error: SQLCore dispatchRequest: exception handling request: <NSSQLSaveChangesRequestContext: 0x600003721140> , <shared NSSecureUnarchiveFromData transformer> threw while encoding a value. with userInfo of (null) Here's the code that tries to save the attributed string: struct AttributedDetailView: View { @ObservedObject var item: Item @State private var notesText = AttributedString() var body: some View { VStack { TextEditor(text: $notesText) .padding() .onChange(of: notesText) { item.attributedString = NSAttributedString(notesText) } } .onAppear { if let nsattributed = item.attributedString { notesText = AttributedString(nsattributed) } else { notesText = "" } } .task { item.attributedString = NSAttributedString(notesText) do { try item.managedObjectContext?.save() } catch { print("core data save error = \(error)") } } } } This is the attribute setup in the Core Data model editor: Is there a workaround for this? I filed FB17943846 if someone can take a look. Thanks.

Hi, Not sure how to describe my issue best: I am using SwiftData and CloudKit to store my data. In the past, when I tested my app on different devices, the data would sync between the devices automatically. For whatever reason this has stopped now and the data no longer syncs. No matter what I do, it feels as if all the data is actually stored just locally on each device. How can I check if the data is actually stored in the cloud and what could be reasons, why its no longer synching between my devices (and yes, I am logged in with the same Apple ID on all devices). Thanks for any hint! Max

I would like to have a SwiftData predicate that filters against an array of PersistentIdentifiers. A trivial use case could filtering Posts by one or more Categories. This sounds like something that must be trivial to do. When doing the following, however: let categoryIds: [PersistentIdentifier] = categoryFilter.map { $0.id } let pred = #Predicate<Post> { if let catId = $0.category?.persistentModelID { return categoryIds.contains(catId) } else { return false } } The code compiles, but produces the following runtime exception (XCode 26 beta, iOS 26 simulator): 'NSInvalidArgumentException', reason: 'unimplemented SQL generation for predicate : (TERNARY(item != nil, item, nil) IN {}) (bad LHS)' Strangely, the same code works if the array to filter against is an array of a primitive type, e.g. String or Int. What is going wrong here and what could be a possible workaround?

Hello everyone, I am experiencing a persistent authentication error when querying a custom user profile record, and the error message seems to be a red herring. My Setup: I have a custom CKRecord type called ColaboradorProfile. When a new user signs up, I create this record and store their hashed password, salt, nickname, and a custom field called loginIdentifier (which is just their lowercase username). In the CloudKit Dashboard, I have manually added an index for loginIdentifier and set it to Queryable and Searchable. I have deployed this schema to Production. The Problem: During login, I run an async function to find the user's profile using this indexed loginIdentifier. Here is the relevant authentication code: func autenticar() async { // ... setup code (isLoading, etc.) let lowercasedUsername = username.lowercased() // My predicate ONLY filters on 'loginIdentifier' let predicate = NSPredicate(format: "loginIdentifier == %@", lowercasedUsername) let query = CKQuery(recordType: "ColaboradorProfile", predicate: predicate) // I only need these specific keys let desiredKeys = ["password", "passwordSalt", "nickname", "isAdmin", "isSubAdmin", "username"] let database = CKContainer.default().publicCloudDatabase do { // This is the line that throws the error let result = try await database.records(matching: query, desiredKeys: desiredKeys, resultsLimit: 1) // ... (rest of the password verification logic) } catch { // The error always lands here logDebug("Error authenticating with CloudKit: \(error.localizedDescription)") await MainActor.run { self.errorMessage = "Connection Error: \(error.localizedDescription)" self.isLoading = false self.showAlert = true } } } The Error: Even though my query predicate only references loginIdentifier, the catch block consistently reports this error: Error authenticating with CloudKit: Field 'createdBy' is not marked queryable. I know createdBy (the system creatorUserRecordID) is not queryable by default, but my query isn't touching that field. I already tried indexing createdBy just in case, but the error persists. It seems CloudKit cannot find or use my index for loginIdentifier and is incorrectly reporting a fallback error related to a system field. Has anyone seen this behavior? Why would CloudKit report an error about createdBy when the query is explicitly on an indexed, custom field? I'm new to Swift and I'm struggling quite a bit. Thank you,

Hi everyone I would like to achieve having unidirectional relationships in my SwiftData project (which I believe is possible: https://developer.apple.com/documentation/updates/swiftdata?changes=_9) but I'm afraid I'm struggling to overcome the errors I'm experiencing. For example, I have the following models: @Model final class Quota { @Attribute(.unique) var id: UUID var allowance: Int @Relationship(inverse: nil) var fish: Fish init(id: UUID = UUID(), fish: Fish, allowance: Int) { self.id = id self.fish = fish self.allowance = allowance } } @Model final class Fish { @Attribute(.unique) var id: Int var name: String init(id: Int, name: String) { self.id = id, self.name = name } } However, when I attempt to save a quota as so: let quota: Quota = .init(fish: Fish(id: 2, name: "Salmon"), allowance: 50) modelContext?.insert(quota) try save() I keep getting the following error: SwiftData.DefaultStore save failed with error: Error Domain=NSCocoaErrorDomain Code=1570 "%{PROPERTY}@ is a required value." UserInfo={NSValidationErrorObject=<NSManagedObject: 0x600002217390> (entity: Fish; id: 0x83319d001151328d <x-coredata://C76A2A64-146E-432F-A565-319B5A2F23F5/Fish/p12>; data: { id = nil; }), NSLocalizedDescription=%{PROPERTY}@ is a required value., NSValidationErrorKey=id, NSValidationErrorValue=null} %{PROPERTY}@ is a required value. However, if I set up Quota and Fish with an inverse relationship then the data saves as expected, so I'm a little confused. Is there anyone out there who can provide some guidance as to why I'm seeing this error when I try to save a record in SwiftData with no inverse relationship? I do fully understand about unidirectional vs bidirectional relationships but I have a scenario where I need the relationship to be unidirectional. Also, as a side note, the Fish record already exists in my database, but if I delete it and try to save the record I still see this error. Thank you so much in advance for any help.

Hello, I have 3 model versions and I'm trying to step through migration. Version 2 makes significant changes to v1. As a result, I've renamed the entities in question by appending _v2 to their name, as the data isn't important to retain. v3, remove's the appended version number from v2. Setting the .xcdatamodeld to v3 and the migrations steps array as follows causes the app to error [ NSLightweightMigrationStage([v1]), NSLightweightMigrationStage([v2]), NSLightweightMigrationStage([v3]), ] CoreData: error: <NSPersistentStoreCoordinator: 0x10740d680>: Attempting recovery from error encountered during addPersistentStore: 0x10770f8a0 Error Domain=NSCocoaErrorDomain Code=134110 "An error occurred during persistent store migration." An error occurred during persistent store migration. Cannot merge multiple root entity source tables into one destination entity root table. I find this odd because if I run the migration independently across app launches, the migration appears to drop the no longer used tables in v2, then re-add them back in v3. So it seems to me that something is not finishing completely with the fully stepped through migration. -- I'm also unable to understand how to use NSCustomMigrationStage I've tried setting it to migrate from v1, to v2, but I'm getting a crash with error Duplicate version checksums across stages detected

Overview I'm developing a document-based app for macOS using SwiftData. When I undo/redo changes using Command-Z/ Command-Shift-Z, the app randomly crashes with the following error: SwiftData/BackingData.swift:425: Fatal error: Failed to retrieve the identifier for \ChildItem.parentItem from KnownKeysDictionary:KnownKeysMap: ["parentItem": 2, "isModified": 1, "index": 0] values: [Optional(0), Optional(false), Optional(DocumentTest.ParentItem)] SwiftData._KKMDBackingData<DocumentTest.ChildItem> And sometimes, instead of the app crashing, my created @Model objects simply disappear. They do not reappear in the @Query on undo/redo. Both of these issues go away when I set modelContext.autosaveEnabled = false The issues are occurring with Xcode 26.4 (17E192) and macOS Tahoe 26.4 (25E246). I have modified the macOS Document App project template to showcase the issue. The project, along with a screen recording of the crash, can be downloaded from here: https://drive.google.com/drive/folders/1aDO34QleTm_rB9BuvVGjzzAP6jDXOc-o?usp=share_link Has anyone else experienced this? I'd like to know if this is a bug in the autosave feature of SwiftData and if I should file a bug report via Feedback Assistant. Steps to Reproduce To recreate the issue, follow these steps: Download and extract the "Xcode Project.zip" file linked above. Open the extracted "DocumentTest" project in Xcode. Build and run the "DocumentTest" app. In the document selection window, click "New Document" at the bottom-left. In the app, click the "+" button at the top-right to add a ParentItem with ChildItems. Click on the added ParentItem's button to modify one of its ChildItems. Repeat steps 5–6 until you have 5 ParentItems with a modified ChildItem. Press Command-Z 10 times to undo all the changes. Press Command-Shift-Z 10 times to redo all the changes. Repeat steps 8–9 until either the app crashes or some of the 5 ParentItems go missing in the list (you may have to repeat them 10–20 times before the issue occurs). If you change line 43 of ContentView.swift to modelContext.autosaveEnabled = false and repeat the same steps above, the app will not crash and no ParentItems will go missing. Code ParentItem Model @Model final class ParentItem { var timestamp: Date @Relationship( deleteRule: .cascade, inverse: \ChildItem.parentItem ) var childItems: [ChildItem] = [] init(timestamp: Date) { self.timestamp = timestamp } } ChildItem Model @Model final class ChildItem { var index: Int var isModified = false var parentItem: ParentItem? init(index: Int) { self.index = index } } Creating, Inserting, and Linking ParentItem and ChildItem // Create and insert ParentItem let newParentItem = ParentItem( timestamp: Date() ) modelContext.insert(newParentItem) // Create and insert ChildItems var newChildItems: [ChildItem] = [] for index in 0..<Int.random(in: 2...8) { let newChildItem = ChildItem(index: index) newChildItems.append(newChildItem) modelContext.insert(newChildItem) } /* Establish relationship between ParentItem and ChildItems */ newParentItem.childItems = newChildItems Modifying ChildItem let firstChildItem = parentItem.childItems .sorted(by: { $0.index < $1.index }).first if let firstChildItem, !firstChildItem.isModified { firstChildItem.isModified = true }

Hi all, In my SwiftUI / SwiftData / Cloudkit app which is a series of lists, I have a model object called Project which contains an array of model objects called subprojects: final class Project1 { var name: String = "" @Relationship(deleteRule: .cascade, inverse: \Subproject.project) var subprojects : [Subproject]? init(name: String) { self.name = name self.subprojects = [] } } The user will select a project from a list, which will generate a list of subprojects in another list, and if they select a subproject, it will generate a list categories and if the user selects a category it will generate another list of child objects owned by category and on and on. This is the pattern in my app, I'm constantly passing arrays of model objects that are the children of other model objects throughout the program, and I need the user to be able to add and remove things from them. My initial approach was to pass these arrays as bindings so that I'd be able to mutate them. This worked for the most part but there were two problems: it was a lot of custom binding code and when I had to unwrap these bindings using init?(_ base: Binding<Value?>), my program would crash if one of these arrays became nil (it's some weird quirk of that init that I don't understand at al). As I'm still learning the framework, I had not realized that the @model macro had automatically made my model objects observable, so I decided to remove the bindings and simply pass the arrays by reference, and while it seems these references will carry the most up to date version of the array, you cannot mutate them unless you have access to the parent and mutate it like such: project.subcategories?.removeAll { $0 == subcategory } project.subcategories?.append(subcategory) This is weirding me out because you can't unwrap subcategories before you try to mutate the array, it has to be done like above. In my code, I like to unwrap all optionals at the moment that I need the values stored in them and if not, I like to post an error to the user. Isn't that the point of optionals? So I don't understand why it's like this and ultimately am wondering if I'm using the correct design pattern for what I'm trying to accomplish or if I'm missing something? Any input would be much appreciated! Also, I do have a small MRE project if the explanation above wasn't clear enough, but I was unable to paste in here (too long), attach the zip or paste a link to Google Drive. Open to sharing it if anyone can tell me the best way to do so. Thanks!

About 4 months ago, I shipped the first version of my app with 4 versioned schemas that, unintentionally, had the same versionIdentifier of 1.2.0 in 2 of them: V1: 1.0.0 V2: 1.1.0 V3: 1.2.0 V4: 1.2.0 They are ordered correctly in the MigrationPlan, and they are all lightweight. Migration works, SwiftData doesn't crash on init and I haven't encountered any issues related to this. The app syncs with iCloud. Questions, preferable for anybody with knowledge of SwiftData internals: What will break in SwiftData when there are 2 duplicate numbers? Not that I would expect it to be safe, but does it happen to be safe to ship an update that changes V4's version to 1.3.0, what was originally intended?

I'm implementing SwiftData with inheritance in an app. I have an Entity class with a property name. This class is inherited by two other classes: Store and Person. The Entity model has a one-to-many relationship with a Transaction class. I can list all my Entity models in a List with a @Query annotation without a problem. However, then I try to access the name property of an Entity from a Transaction relationship, the app crashes with the following error: Thread 1: Fatal error: Never access a full future backing data - PersistentIdentifier(id: SwiftData.PersistentIdentifier.ID(backing: SwiftData.PersistentIdentifier.PersistentIdentifierBacking.managedObjectID(0x96530ce28d41eb63 <x-coredata://DABFF7BB-C412-474E-AD50-A1F30AC6DBE9/Person/p4>))) with Optional(F07E7E23-F8F0-4CC0-B282-270B5EDDC7F3) From my attempts to fix the issue, I noticed that: The crash seems related to the relationships with classes that has inherit from another class, since it only happens there. When I create new data, I can usually access it without any problem. The crash mostly happens after reloading the app. This error has been mentioned on the forum (for example here), but in a context not related with inheritance. You can find the full code here. For reference, my models looks like this: @Model class Transaction { @Attribute(.unique) var id: String var name: String var date: Date var amount: Double var entity: Entity? var store: Store? { entity as? Store } var person: Person? { entity as? Person } init( id: String = UUID().uuidString, name: String, amount: Double, date: Date = .now, entity: Entity? = nil, ) { self.id = id self.name = name self.amount = amount self.date = date self.entity = entity } } @Model class Entity: Identifiable { @Attribute(.preserveValueOnDeletion) var name: String var lastUsedAt: Date @Relationship(deleteRule: .cascade, inverse: \Transaction.entity) var operations: [Transaction] init( name: String, lastUsedAt: Date = .now, operations: [Transaction] = [], ) { self.name = name self.lastUsedAt = lastUsedAt self.operations = operations } } @available(iOS 26, *) @Model class Store: Entity { @Attribute(.unique) var id: String var locations: [Location] init( id: String = UUID().uuidString, name: String, lastUsedAt: Date = .now, locations: [Location] = [], operations: [Transaction] = [] ) { self.locations = locations self.id = id super.init(name: name, lastUsedAt: lastUsedAt, operations: operations) } } In order to reproduce the error: Run the app in the simulator. Click the + button to create a new transaction. Relaunch the app, then click on any transaction. The app crashes when it tries to read te name property while building the details view.

Hello, thank you Apple for supporting custom store with SwiftData and the Schema type is superb to work with. I have successfully set one up with SQL and have some feedback and issues regarding its APIs. There’s a highlighted message in the documentation about not using internal restricted symbols directly, but they contradict with the given protocols and I am concerned about breaking any App Store rules. Are we allowed to use these? If not, they should be opened up as they’re useful. BackingData is required to set up custom snapshots, initialization, and getting/setting values. And I want to use it with createBackingData() to directly initialize instances from snapshots when transferring them between server and client or concurrency. RelationshipCollection for casting to-many relationships from backing data or checking if an array contains a PersistentModel. SchemaProperty for type erasure in a collection. Schema.Relationship has KeyPath properties, but it is missing for Schema.Attribute and Schema.CompositeAttribute. Which means you can’t purely depend on the schema to map data. I am unable to access the properties of a custom struct type in a predicate unless I use Mirror with schemaMetadata() or CustomStringConvertible on the KeyPath directly to extract it. Trivial, but… the KeyPath property name is inconsistent (it’s all lowercase). It would be nice to retrieve property names from custom struct types, since you are unable access CodingKeys that are auto synthesized by Codable for structs. But I recently realized they’re a part Schema.CompositeAttribute, however I don’t know how to match these without the KeyPath… I currently map my entities using CodingKeys to their PredicateCodableKeyPathProviding.… but I wish for a simpler alternative! It’s unclear how to provide the schema to the snapshot before new models are created. I currently use a static property, but I want to make it flexible if more schemas and configurations are added later on. I considered saving and loading the schema in a temporary location, but doubtful that the KeyPath values will be available as they are not Codable. I suspect schemaMetadata() has the information I need to map the backing data without a schema for snapshots, but as mentioned previously, properties are inaccessible… Allow access to entity metatypes, like value types from SchemaProperty. They’re useful for getting data out of snapshots and casting them to CodingKeys and PredicateCodableKeyPathProviding. They do not carry over when you provide them in the Schema. I am unable to retrieve the primary key from PersistentIdentifier. It seems like once you create one, you can’t get it out, like the DataStoreConfiguration in ModelContainer is not the one you used to set it up. I cannot cast it, it is an entirely different struct? I have to use JSONSerialization to extract it, but I want to get it directly since it is not a column in my database. It is transformed when it goes to/from my tables. It’s unknown how to support some schema options, such as Spotlight and CloudKit. Allow for extending macro options, such as adding options to set as primary key, whether to auto increment, etc… You can create a schema for super and sub entities, but it doesn’t appear you can actually set them up from the @Model macro or use inheritance on these models… SwiftData history tracking seems incomplete for HistoryDelete, because that protocol requires HistoryTombstone, but this type cannot be instantiated, nor does it contain anything useful to infer from. As an aside, I want to create my own custom ModelActor that is a global actor. However, I’m unable to replicate the executor that Apple provides where the executor has a ModelContext, because this type does not conform to Sendable. So how did Apple do this? The documentation doesn’t mention unchecked Sendable, but I figure if the protocol is available then we would be able to set up our own. And please add concurrency features! Anyway, I hope for more continued support in the future and I am looking forward to what’s new this WWDC! 😊

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?

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???

CloudKit CKRecordZone Deletion Issue Problem: CloudKit record zones deleted via CKDatabase.modifyRecordZones(deleting:) or CKModifyRecordZonesOperation are successfully removed but then reappear. I suspect they are automatically reinstated by CloudKit sync, despite successful deletion confirmation. Environment: SwiftData with CloudKit integration Custom CloudKit zones created for legacy zone-based sharing Observed Behavior: Create custom zone (e.g., "TestZone1") via CKDatabase.modifyRecordZones(saving:) Copy records to zone for sharing purposes Delete zone using any CloudKit deletion API - returns success, no errors Immediate verification: Zone is gone from database.allRecordZones() After SwiftData/CloudKit sync or app restart: Zone reappears Reproduction: Tested with three different deletion methods - all exhibit same behaviour: modifyRecordZones(deleting:) async API CKModifyRecordZonesOperation (fire-and-forget) CKModifyRecordZonesOperation with result callbacks Zone deletion succeeds, change tokens (used to track updates to shared records) cleaned up But zones are restored presumably by CloudKit background sync Expected: Deleted zones should remain deleted Actual: Zones are reinstated, creating orphaned zones

Description: I'm experiencing a critical issue with SwiftData custom migrations where objects created during migration appear to be inserted successfully but aren't persisted or found by queries after migration completes. The migration logs show objects being created, but subsequent queries return zero results. Problem Details: I'm migrating from schema version V2 to V3, which involves: Renaming Person class to GroupData Keeping the same data structure but changing the class name Using a custom migration stage to copy data from old to new schema Migration Code: swift static let migrationV2toV3 = MigrationStage.custom( fromVersion: LinkMapV2.self, toVersion: LinkMapV3.self, willMigrate: { context in do { let persons = try context.fetch(FetchDescriptor<LinkMapV2.Person>()) print("Found (persons.count) Person objects to migrate") // ✅ Shows 11 objects for person in persons { let newGroup = LinkMapV3.GroupData( id: person.id, // Same UUID name: person.name, // ... other properties ) context.insert(newGroup) print("Inserted GroupData: '\(newGroup.name)'") // ✅ Confirms insertion } try context.save() // ✅ No error thrown print("Successfully migrated \(persons.count) objects") // ✅ Confirms save } catch { print("Migration error: \(error)") } }, didMigrate: { context in do { let groups = try context.fetch(FetchDescriptor<LinkMapV3.GroupData>()) print("Final GroupData count: \(groups.count)") // ❌ Shows 0 objects! } catch { print("Verification error: \(error)") } } ) Console Output: text === MIGRATION STARTED === Found 11 Person objects to migrate Migrating Person: 'Riverside of pipewall' with ID: 7A08C633-4467-4F52-AF0B-579545BA88D0 Inserted new GroupData: 'Riverside of pipewall' ... (all 11 objects processed) ... === MIGRATION COMPLETED === Successfully migrated 11 Person objects to GroupData === MIGRATION VERIFICATION === New GroupData count: 0 // ❌ PROBLEM: No objects found! What I've Tried: Multiple context approaches: Using the provided migration context Creating a new background context with ModelContext(context.container) Using context.performAndWait for thread safety Different save strategies: Calling try context.save() after insertions Letting SwiftData handle saving automatically Multiple save calls at different points Verification methods: Checking in didMigrate closure Checking in app's ContentView after migration completes Using both @Query and manual FetchDescriptor Schema variations: Direct V2→V3 migration Intermediate V2.5 schema with both classes Lightweight migration with @Attribute(originalName:) Current Behavior: Migration runs without errors Objects appear to be inserted successfully context.save() completes without throwing errors But queries in didMigrate and post-migration return empty results The objects seem to exist in a temporary state that doesn't persist Expected Behavior: Objects created during migration should be persisted and queryable Post-migration queries should return the migrated objects Data should be available in the main app after migration completes Environment: Xcode 16.0+ iOS 18.0+ SwiftData Swift 6.0+ Key Questions: Is there a specific way migration contexts should be handled for data to persist? Are there known issues with object persistence in custom migrations? Should we be using a different approach for class renaming migrations? Is there a way to verify that objects are actually being written to the persistent store? The migration appears to work perfectly until the verification step, where all created objects seem to vanish. Any guidance would be greatly appreciated! Additional Context from my investigation: I've noticed these warning messages during migration that might be relevant: text SwiftData.ModelContext: Unbinding from the main queue. This context was instantiated on the main queue but is being used off it. error: Persistent History (76) has to be truncated due to the following entities being removed: (Person) This suggests there might be threading or context lifecycle issues affecting persistence. Let me know if you need any additional information about my setup or migration configuration!

I have implemented CKSyncEngine synchronization, and it works well. I can update data on one device and see the changes propagate to another device quickly. However, the initial sync when a user downloads the app on a new device is a significant issue for both me and my users. One problem is that the sync engine fetches deletion events from the server. On a new device, the local database is empty, so these deletions are essentially no-ops. This would not be a big problem if there were only a few records or if it was fast. I measured the initial sync and found that there are 150 modified records and 62,168 deletions. Counting these alone takes over five minutes, even without processing them. The deletions do nothing because the local database has nothing to delete, yet they still add a significant delay. I understand that the sync engine ensures consistency across all devices, but five minutes of waiting with the app open just to insert a small number of records is excessive. The problem would be worse if there were tens of thousands of new records to insert, since downloading and saving the data would take even longer. This leads to a poor user experience. Users open the app and see data being populated for several minutes, or they are stuck on a screen that says the data is being synchronized with iCloud. I am wondering if there is a way to make the sync engine ignore deletion events when the state serialization is nil. Alternatively, is there a recommended method for handling initial synchronization more efficiently? One idea I considered is storing all the data as a backup in iCloud Documents, along with the state serialization at that point in time. When a user opens the app for the first time, I could download the file, extract the data, and set the state serialization to the saved value. I am not sure if this would work. I do not know if state serialization is tied to the device or if it only represents the point where the sync engine left off. My guess is that it might reference some local device storage. I am not sure what else to try. I could fetch all data using CloudKit, create the sync engine with an empty state serialization, and let it fetch everything again, but that would still take a long time. My records are very small, mostly a date when something happened and an ID referencing the parent. Since the app tracks watched episodes, I only store the date the user watched the episode and the ID of that episode.

Hi. I'm hoping someone might be able to help us with an issue that's been affecting our standalone watchOS app for some time now. We've encountered consistent crashes on Apple Watch devices when the app enters the background while the device is offline (i.e., no Bluetooth and no Wi-Fi connection). Through extensive testing, we've isolated the problem to the use of NSPersistentCloudKitContainer. When we switch to NSPersistentContainer, the crashes no longer occur. Interestingly, this issue only affects our watchOS app. The same CloudKit-based persistence setup works reliably on our iOS and macOS apps, even when offline. This leads us to believe the issue may be specific to how NSPersistentCloudKitContainer behaves on watchOS when the device is disconnected from the network. We're targeting watchOS 10 and above. We're unsure if this is a misconfiguration on our end or a potential system-level issue, and we would greatly appreciate any insight or guidance.

Hi, I'm having trouble implementing iCloud Drive in my app. I've already taken the obvious steps, including enabling iCloud Documents in Xcode and selecting a container. This container is correctly specified in my code, and in theory, everything should work. The data generated by my app should be saved to iCloud Drive in addition to local storage. The data does get stored in the Files app, but the automatic syncing to iCloud Drive doesn’t work as expected. I’ve also considered updating my .entitlements file. Since I’m at a loss, I’m reaching out for help maybe I’ve overlooked something important that's causing it not to work. If anyone has an idea, please let me know. Thanks in advance!

Hello everyone, I'm trying to adopt the new Staged Migrations for Core Data and I keep running into an error that I haven't been able to resolve. The error messages are as follows: warning: Multiple NSEntityDescriptions claim the NSManagedObject subclass 'Movie' so +entity is unable to disambiguate. warning: 'Movie' (0x60000350d6b0) from NSManagedObjectModel (0x60000213a8a0) claims 'Movie'. error: +[Movie entity] Failed to find a unique match for an NSEntityDescription to a managed object subclass This happens for all of my entities when they are added/fetched. Movie is an abstract entity subclass, and it has the error error: +[Movie entity] Failed to find which is unique to the subclass entities, but this occurs for all entities. The NSPersistentContainer is loaded only once, and I set the following option after it's loaded: storeDescription.setOption( [stages], forKey: NSPersistentStoreStagedMigrationManagerOptionKey ) The warnings and errors only appear after I fetch or save to context. It happens regardless of whether the database was migrated or not. In my test project, using the generic NSManagedObject with NSEntityDescription.insertNewObject(forEntityName: "MyEntity", into: context) does not cause the issue. However, using the generic NSManagedObject is not a viable option for my app. Setting the module to "Current Project Module" doesn't change anything, except that it now prints "claims 'MyModule.Show'" in the warnings. I have verified that there are no other entities with the same name or renameIdentifier. Has anyone else encountered this issue, or can offer any suggestions on how to resolve it? Thanks in advance for any help!

I work on an app that saves data to the Documents folder in the users iCloud Drive. This uses the iCloud -> iCloud Documents capability with a standard container. We've noticed an issue where a user will delete the apps data by doing to Settings > {Name} > iCloud > Storage > App Name > select "delete data from iCloud", and then our app can no longer write to or create the Documents folder. Once that happens, we get this error: Error Domain=NSCocoaErrorDomain Code=513 "You don't have permission to save the file "Documents" in the folder "iCloud~your~bundle~identifier"." UserInfo={NSFilePath=/private/var/mobile/Library/Mobile Documents/iCloud~your~bundle~identifier/Documents, NSURL=file:///private/var/mobile/Library/Mobile%20Documents/iCloud~your~bundle~identifier/Documents, NSUnderlyingError=0x1102c7ea0 {Error Domain=NSPOSIXErrorDomain Code=13 "Permission denied"}} This is reproducible using the sample project here https://developer.apple.com/documentation/uikit/synchronizing-documents-in-the-icloud-environment. Steps to reproduce in that project: Tap the plus sign in the top right corner to create a new document Add a document name and tap "Save to Documents" Go to Settings > {Name} > iCloud > Storage > SimpleiCloudDocument App Name > select "delete data from iCloud" Reopen the app and repeat steps 1-2 Observe error on MainViewController+Document.swift:59 Deleting and reinstalling the app doesn't seem to help.