SwiftData includes support for CloudKit sync. However, I don't see any way to add conflict resolution behavior. For example, if different devices set different values for a field, or if a relationship is orphaned because of a deletion on another device, the application has to handle this somehow. In Core Data (which SwiftData wraps), you can handle this with the conflict resolution system (docs) and classes like NSMergePolicy. Is any of this accessible in SwiftData? If not, how do you deal with conflicts when syncing a SwiftData model with the cloud?

Has anyone successfully persisted Color, particularly in SwiftData? So far my attempts have failed: Making Color conform to Codable results in a run time error (from memory something about ColorBox). Color.Resolved already conforms Codable but this results in "SwiftData/ModelCoders.swift:124: Fatal error: Composite Coder only supports Keyed Container" None of the other color types conform to Codable (CGColor, NSColor and UIColor) so does the swift language really not have a persistable color type?

Recently, I have made quite extensive changes to my schema and need to migrate my CoreData + CloudKit model to a new version. The changes require me to use a custom NSEntityMigrationPolicy because I have a rather complex mapping between some old entities and new entities. I have added a new model version. Deleted some entities, and added some entities. I have defined the NSEntityMigrationPolicy with createDestinationInstances(forSource:in:manager:) and createRelationships(forDestination:in:manager:). I have created a new Core Data Mapping Model. This was probably unnecessary. Within the Core Data Mapping Model, I have specified Custom Policy for all entities. In my container setup, I added two options, as below: storeDescription.setOption(false as NSNumber, forKey: NSMigratePersistentStoresAutomaticallyOption) storeDescription.setOption(false as NSNumber, forKey: NSInferMappingModelAutomaticallyOption) I mostly followed a "Core Data Heavyweight Migration" guide. I'm unable to share the link, but it can be quite easily found on the web. (It's not for CloudKit specifically.) When I run my app, I am getting the most basic of errors, which is: The managed object model version used to open the persistent store is incompatible with the one that was used to create the persistent store. So I guess that migration wasn't even attempted, which makes sense because I set NSMigratePersistentStoresAutomaticallyOption to false. I tried to go beyond what I could find on the web and attempted to manually initialize migration: let sourceModel = container.persistentStoreCoordinator.managedObjectModel guard let modelURL = Bundle.main.url(forResource: "MyModelName", withExtension: "xcdatamodeld") else { fatalError("Unable to locate model file.") } guard let destinationModel = NSManagedObjectModel(contentsOf: modelURL) else { fatalError("Unable to load destination model.") } let migrationManager = NSMigrationManager(sourceModel: sourceModel, destinationModel: destinationModel) let mappingModel = NSMappingModel(from: [Bundle.main], forSourceModel: sourceModel, destinationModel: destinationModel)! migrationManager.currentEntityMapping.entityMigrationPolicyClassName = "MyMigrationPolicyClassName" I am then stuck at the migrateStore(from:type:mapping:to:type:) method. It seems to target only local storage, not CloudKit. Otherwise, what do I provide for URLs and types? Any guidance for custom logic CoreData with CloudKit migration would be greatly appreciated.

Hi, I have been working on some kind of network filtering app for iOS using Content Filter Provider. And I have stored rules for each domain. As of right now, I use UserDefaults with my app's bundle suite to store and observe rules. I have also read this documentation page for UserDefaults link. Is it okay to use UserDefaults in my case, if I have rules added/modified dynamically as the flow is intercepted, or should I pick some other approach like Core Data, SwiftData, etc.? Thank you!

I’m using NSPersistentCloudKitContainer and I’m utilising the public database and also the user’s private database. For example I have an entity called Category which has a many-to-many relationship to an entity called NewsArticle. So the NewsArticles exist in the public database for the user to browse, but he can add them to a category which will live in his private database. So that’s my question, is it possible for an entity which exists a in the private database to have a relationship to another entity in a public database?

Hi, We are having problems with IOs Quick Look not working. Specifically, the AR button being greyed out after having opened the Scene / AR model previously. This is all running off our Web-App. What we have figured out is clearing the device's cache solves the issue and the greyed out button turns blue and clickable again. We are receiving this issue very inconsistently though - on iPad as well as iPhone and on both newer and older IOs versions. Very happy for any responses and advice to solve this issue as its behaviour makes the quick look function - even if it's great (when it works) unviable for Production (because it doesn't work consistently). Best Regards

How can we identify whether the remote change notification is triggered because some data was changed on a different device and it is downloaded from CloudKit, or it is triggered from the current device because new entity was saved into database. Because this notification is posted when both remote data is downloaded or local data is created. It would be great if there is a way to understand the origin of the notification.

I am using a Mac Catalyst app and saving the content of the app in core data. After uninstalling the app the saved core data file is not getting deleted. Due to this I am having major bugs during launch of the app. My requirement is core data contents should be removed once the app is uninstalled. Anybody with solutions for this?

CoreData: Zone metadata is missing it's encoded share data but is marked for a mutation: <CKRecordZoneID: 0x600003f044e0; zoneName=com.apple.coredata.cloudkit.share.30BE5FAE-3FE0-4142-90C4-E78FFA90B2A2, ownerName=defaultOwner> - <decode: bad range for [%@] got [offs:312 len:1242 within:0]>

I have a CoreData model, in a Swift Package with tests. I can successfully run the tests, when I load the model using NSPersistentContainer, however attempting this with NSPersistentCloudKitContainer always fails in the call to loadPersistentStores(completionHandler block: @escaping (NSPersistentStoreDescription, Error?) -> Void) The error is : [CK] BUG IN CLIENT OF CLOUDKIT: Not entitled to listen to push notifications. Please add the 'aps-connection-initiate' entitlement. This issue is described on StackOverflow however, the accepted solution does not appear to work in my case. I have tried adding the aps-connection-initiate key to my App Info.plist, the Test Info.plist and the SPM bundle. No change. (NB. adding this to the entitlements file just breaks auto signing). I have enabled App entitlements for App Groups, Remote Notifications background mode, Push Notifications and iCloud CloudKit with a store identifier. I have checked my model. All relationships have inverses. No unique constraints, etc. etc. I am sharing a Bundle ID with a previous version of the App, that also uses CoreData+CloudKit, each version has it's own Model and container identifier, each container identifier is available in the provisioning profile. The new version of the model has two NSPersistentStoreDescriptions, one is configured for CloudKit, the other is a local cache. I am completely stuck, suggestions would be very welcome.

Any one getting any issues with NavigaitonLink to seemingly innocuous views freezing when tapped on? 1 CPU at 100% memory steadily increasing until app gets killed by the system. Will freeze if any NavigationLink on the view is tapped if certain views are linked to using NavigaitonLink. I note some people have been getting similar freezes if they use @AppStorage, but I'm not using @AppStorage. I do use CoreData tho. tho I have some views that use core data that don't freeze. https://developer.apple.com/forums/thread/708592?page=1#736374022 has anyone experienced similar issues? or know the cause. it doesn't seem to be any of my code because if I pause the debugger it stops on system code.

Hello, I have class file, which should save data coreData and Im only able to save data via ui. Do you have any example, how can I save data in core data via class files? Greeting Fabian

I am currently writing an app that is about writing stories. As of now, it is fairly simple: ContentView is your "Collection" of stories. PopupView is when you click on a button in ContentView. In popup view you enter the story title. Once you do that, you are brought to a blank page which is StoryView, where the NavigationTitle is what your story title is. Once I finish the story and leave the page / StoryView, it is still there, but once I close the app on my phone and reopen it, the story is gone and is not saved. I am a relatively new developer, so ive been relying on ChatGPT and Google Gemini for the saving parts of this, but it rarely works, and the furthest ive gotten with it is that it saves the story title but doesn't save the content of the story. I have a feeling that the AI is overdoing it as well. If anyone could help, please do so. Ive been trying to fix this for days. If you need me to provide any code, I am happy to do so. [Edited by Moderator]

Hello. I recently released a new version (2.6) of my CloudKit syncing CoreData based app. The new version uses v18 of my data model. V18 is exactly like v17, except for a new optional string field in one of the entities. I diffed the two model versions to be extra sure. During my test I did not encounter any crash, and I also tested automatic migration, installing 2.55 and building 2.6 on top of it. No troubles. However my crash logger reports a number of crashes among my users. It's not a huge numbers (10 users over about 900 or more) but I am surprised it crashes at all. The crash happens when I call NSPersistentCloudKitContainer.loadPersistentStores, I get this error in the completion block: The model used to open the store is incompatible with the one used to create the store" I always assumed these slight changes (new field added to an existing model) did not require a manual migration. Any suggestions?

I am trying to profile my app for 'Data Persistence', but I am not getting any data in the Instruments. I tried restarting Xcode and Mac, still no progress. It is showing blank graph for faults, fetches and saves

We currently have a shoebox-based architecture but want to transition to a document-based architecture, so UIManagedDocument seems like an obvious choice. However, the UIManagedDocument API seems outdated given the relatively newer NSPersistentContainer API. Also, it’s not clear if UIManagedDocument’s managedObjectContext can be used on the main thread or not. Ideally, I would like to see a persistentContainer property added to UIManagedDocument which could then be used to obtain the view context or a background managed object context. Does anyone have any suggestions on the latest best practices for document-based architectures using CoreData? I’m more interested in Swift implementations, but knowing best practices for SwiftUI and SwiftData would be helpful too.

Hi all In pursuit of adopting widgets in my application, I have transitioned from AppSupport to AppGroup as storage location for Core Data. I have done a migration process/flow that goes as follows and which have been tested multiple times although I have yet to publish the update: Check if migration has taken place or not 1a. if yes continue to app 1b. If no continue flow Begin migration process 2a. Backup original store in AppSupport 2b. Migrate store to AppGroup 2c. Migrate userdefaults to AppGroup 2d. Update userdefaults with true for both hasMigratedToAppGroup and hasMigratedUserDefaultsToAppGroup Is there any tips or stuff to look for that hasn’t been taken in to account? How have you done it previously, and what would be recommended? Also, is there some specific tests to run/over many times get a baseline of how many is succeeding or failing? Thanks in advance.

persist images even after the app is uninstalled, if we reinstall the app can we display same images in app? but our app not use any cloud or server. Thanks in advance.

I am building an app that manages ScreenTime and I would like to persist the tokens of which apps are frequently limited to CoreData locally. I attempted to do so by converting to a string but was unable to find a way to initialize an ActivityCategoryToken with a string. Is this possible? Am I going about it the wrong way? Thanks.