Some users of my app are reporting total loss of data while using the app. This is happening specifically when they enable iCloud sync. I am doing following private func setupContainer(enableICloud: Bool) { container = NSPersistentCloudKitContainer(name: "") container.viewContext.automaticallyMergesChangesFromParent = true container.viewContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy guard let description: NSPersistentStoreDescription = container.persistentStoreDescriptions.first else { fatalError() } description.setOption(true as NSNumber, forKey: NSPersistentHistoryTrackingKey) description.setOption(true as NSNumber, forKey: NSPersistentStoreRemoteChangeNotificationPostOptionKey) if enableICloud == false { description.cloudKitContainerOptions = nil } container.loadPersistentStores { description, error in if let error { // Handle error } } } When user clicks on Toggle to enable/disable iCloud sync I just set the description.cloudKitContainerOptions to nil and then user is asked to restart the app. Apart from that I periodically run the clear history func deleteTransactionHistory() { let sevenDaysAgo = Calendar.current.date(byAdding: .day, value: -7, to: Date())! let purgeHistoryRequest = NSPersistentHistoryChangeRequest.deleteHistory(before: sevenDaysAgo) let backgroundContext = container.newBackgroundContext() backgroundContext.performAndWait { try! backgroundContext.execute(purgeHistoryRequest) } }

I'm currently using Xcode 16 Beta (16A5171c) and I'm getting a crash whenever I attempt to fetch using my ModelContext in my SwiftUI video using the environment I'm getting a crash specifically on iOS 18 simulators. I've opened up a feedback FB13831520 but it's worth noting that I can run the code I'll explain in detail below on iOS 17+ simulator and devices just fine. I'm getting the following crash: *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'The specified URI is not a valid Core Data URI: x-coredata:///MyApp/XXXXX-XXXXX-XXXX-XXXX-XXXXXXXXXXXX' It's almost as if on iOS18 SwiftData is unable to find the file on the simulator to perform CRUD operations. All I'm doing in my project is simply fetching data using the modelContext. func contains(_ model: MyModel, in context: ModelContext) -> Bool { let objId = palette.persistentModelID let fetchDesc = FetchDescriptor<MyModel>(predicate: #Predicate { $0.persistentModelID == objId }) let itemCount = try? context.fetchCount(fetchDesc) return itemCount != 0 }

Since the iOS 18 and Xcode 16, I've been getting some really strange SwiftData errors when passing @Model classes around. The error I'm seeing is the following: SwiftData/BackingData.swift:409: Fatal error: This model instance was destroyed by calling ModelContext.reset and is no longer usable. PersistentIdentifier(id: SwiftData.PersistentIdentifier.ID(url: x-coredata://34EE9059-A7B5-4484-96A0-D10786AC9FB0/TestApp/p2), implementation: SwiftData.PersistentIdentifierImplementation) The same issue also happens when I try to retrieve a model from the ModelContext using its PersistentIdentifier and try to do anything with it. I have no idea what could be causing this. I'm guessing this is just a bug in the iOS 18 Beta, since I couldn't find a single discussion about this on Google, I figured I'd mention it. if someone has a workaround or something, that would be much appreciated.

Since the iOS 18 and Xcode 16, I've been getting some really strange SwiftData errors when passing @Model classes around. SwiftData/BackingData.swift:409: Fatal error: This model instance was destroyed by calling ModelContext.reset and is no longer usable. PersistentIdentifier(id: SwiftData.PersistentIdentifier.ID(url: x-coredata://D0F0E233-8D1D-4020-924B-BA56959140FD/ListModel/p10), implementation: SwiftData.PersistentIdentifierImplementation) The same issue also happens when I try to retrieve a model from the ModelContext using its PersistentIdentifier and try to do anything with it. I have no idea what could be causing this. This is my actor @ModelActor actor ListCrudOperations:ObservableObject{ func add(list:ListModel){ modelContext.insert(list) try? modelContext.save() } func delete(identifier:PersistentIdentifier){ guard let list = self[identifier, as: ListModel.self] else { print("error") return } if list.listType == .task{ list.reminders!.forEach { reminder in TaskModel.delete(modelContext: modelContext, reminder: reminder) NotificationService.deleteReminders(name: reminder.title!, Id: reminder.id) } } else if list.listType == .subscription { list.subscription!.forEach({ sub in Subscription.delete(modelContext: modelContext, subscription: sub) NotificationService.deleteReminders(name: sub.ServiceName, Id: sub.id) }) } else if list.listType == .link { list.links!.forEach ({link in Links.delete(modelContext: modelContext, link: link) NotificationService.deleteNotificationForLink(title: link.name, linkID: link.id) } ) } modelContext.delete(list) try? modelContext.save() } func addReminder(reminder:TaskModel, identifier:PersistentIdentifier){ guard let list = self[identifier, as: ListModel.self] else { print("error") return } list.reminders!.append(reminder) reminder.list = list try? modelContext.save() } func addSubscription(subscription:Subscription, identifier:PersistentIdentifier){ guard let list = self[identifier, as: ListModel.self] else { print("error") return } list.subscription!.append(subscription) subscription.list = list try? modelContext.save() } func addLink(link:Links, identifier: PersistentIdentifier) { guard let list = self[identifier, as: ListModel.self] else { print("error") return } list.links?.append(link) link.list = list try? modelContext.save() } func fetchListByType(type:ListType) -> [ListModel] { let type = SwiftTaskSchemaV8.ListModel.ListType(rawValue: type.rawValue)! let fetchDescriptor = FetchDescriptor<ListModel>() do { let list = try modelContext.fetch(fetchDescriptor) let list2 = try list.filter(#Predicate { $0.listType == type }) return list2 }catch{ return [] } } func fetchListsForMultipleTypes(_ types: [ListType]) -> [ListModel] { return types.flatMap { type in fetchListByType(type: type) } } func fetchAllList() -> [ListModel] { let fetchDescriptor = FetchDescriptor<ListModel>(sortBy: [.init(\.createdDate)]) do { let list = try modelContext.fetch(fetchDescriptor) return list }catch{ return [] } } }``` and this is how i am calling it @Environment(.modelContext) private var context let listOperation = ListCrudOperations(modelContainer: context.container) let list = ListModel(name: name, color: self.color, icon: self.icon, listType: ListModel.ListType(rawValue: picked.rawValue)!) Task { await listOperation.add(list: list) await MainActor.run{ withAnimation(.bouncy){ self.list.append(list) } CrashServices.shared.addLogs(message: "folder added") } }

Hello, I’m struggling to go from unversioned data model in SwiftData, to starting to version it. Some FYI: I’m using CloudKit I’m using a widget, where I also pass in my data model and setup my container, this is shared over a group container/app group. My migration is very simple, I’m adding a property which is not optional ( has default value set, and a default value in initialiser ). Model: @Model class NicotineModel { var nicotineType: NicotineType = NicotineType.snus var startDate: Date = Date() + 30 var spendingAmount: Int = 0 var nicotinePerDay: Int = 0 var quittingMethod: QuittingMethod = QuittingMethod.coldTurkey // this is the change in the model, V1 doesn't have the quittingMethod property var setupComplete: Bool = false I’ve tried with: static let migrateV1toV2 = MigrationStage.lightweight( fromVersion: SchemaV1.self, toVersion: SchemaV2.self ) But also static let migrateV1toV2 = MigrationStage.custom( fromVersion: SchemaV1.self, toVersion: SchemaV2.self, willMigrate: nil, didMigrate: { context in let nicotineModels2 = try context.fetch(FetchDescriptor<SchemaV2.NicotineModel>()) let nicotineModels = try context.fetch(FetchDescriptor<SchemaV1.NicotineModel>()) for model in nicotineModels { let newModel = SchemaV2.NicotineModel( nicotineType: model.nicotineType, startDate: model.startDate, spendingAmount: model.spendingAmount, nicotinePerDay: model.nicotinePerDay, setupComplete: model.setupComplete, quittingMethod: .coldTurkey ) context.insert(newModel) context.delete(model) } try context.save() } ) and simply static let migrateV1toV2 = MigrationStage.custom( fromVersion: SchemaV1.self, toVersion: SchemaV2.self, willMigrate: nil, didMigrate: { context in let nicotineModels = try context.fetch(FetchDescriptor<SchemaV2.NicotineModel>()) for model in nicotineModels { model.quittingMethod = .coldTurkey } try context.save() } ) This gives me the error on startup SwiftData/ModelCoders.swift:1762: Fatal error: Passed nil for a non-optional keypath \NicotineModel.quittingMethod On https://icloud.developer.apple.com I can see that the record doesn't include my quittingMethod. I'm loosing my mind, what am I doing wrong?

Hi Folks, starting with iOS18 and using Xcode16, accessing fetchedProperties results in an error. I identified the issue to occur as soon as the initialization of a fetched property with external binary data storage starts. Console output during debugging: *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'This expression has evaluation disabled' *** First throw call stack: [...] libc++abi: terminating due to uncaught exception of type NSException Console output when trying to "print" the item via the contact menu of the debugger: Printing description of variable: error: error: Execution was interrupted, reason: internal ObjC exception breakpoint(-6).. The process has been returned to the state before expression evaluation. Message from debugger: killed The identical code works with iOS before iOS 18 (same for iPadOS 18). Does anyone observed a similar issue and figured out a solution already? Cheers, folox

Hi! I'm using CoreData + CloudKit. It works well both on macOS and iOS, however, I can't make it work with extensions (share, action, keyboard). I get Invalid bundle ID for container error: <CKSchedulerActivity: 0x3029f4d20; identifier=com.apple.coredata.cloudkit.activity.export.A65D5B7A-18AA-400A-B25F-F042E46646F6, priority=2, container=iCloud.com.org.app.dev:Sandbox, relatedApplications=( "com.org.App.dev.App-Keyboard" ), xpcActivityCriteriaOverrides={ ActivityGroupName = "com.apple.coredata.cloudkit.App Keyboard.A65D5B7A-18AA-400A-B25F-F042E46646F6"; Delay = 0; Priority = Utility; }> error: CoreData+CloudKit: -[NSCloudKitMirroringDelegate _recoverFromPartialError:forStore:inMonitor:](2812): <NSCloudKitMirroringDelegate: 0x303fd82d0>: Error recovery failed because the following fatal errors were found: { "<CKRecordZoneID: 0x300ef9bc0; zoneName=com.apple.coredata.cloudkit.zone, ownerName=__defaultOwner__>" = "<CKError 0x300efa5e0: \"Permission Failure\" (10/2007); server message = \"Invalid bundle ID for container\"; op = xxxxxxx; uuid = zzzzz-xxxxx; container ID = \"iCloud.com.org.app.dev\">"; } I checked everything 10x: profiles, bundle ids, entitlements, etc. I even removed all local provisioning profiles and recreated them, I also tried setting different CloudKit container, but nothing helps. I tested it on a real device. My setup: main app bundle id: com.org.App.dev keyboard bundle id: com.org.App.dev.App-Keyboard action extension bundle id: com.org.App.dev.Action-Extension CloudKit container id: iCloud.com.org.app.dev I keep the CoreData database in the app group container, but I also tried locally and it doesn't really matter. This is how I setup my CoreData: self.persistentContainer = NSPersistentCloudKitContainer(name: "AppCoreModel") persistentContainer.persistentStoreDescriptions = [createCloudStoreDescription()] persistentContainer.loadPersistentStores { [self] _, error in if let error { logError("Could not load Core Data store \(error)") } else { persistentContainer.viewContext.automaticallyMergesChangesFromParent = true persistentContainer.viewContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy logDebug(persistentContainer.persistentStoreDescriptions.first?.url?.absoluteString ?? "") logDebug("Core Data store loaded") } } private func createCloudStoreDescription() -> NSPersistentStoreDescription { let cloudStoreOptions = NSPersistentCloudKitContainerOptions( containerIdentifier: "iCloud.com.org.app.dev" ) cloudStoreOptions.databaseScope = .private let documentsUrl = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: AppConstants.appGroupId)! let cloudStoreDescription = NSPersistentStoreDescription( url: documentsUrl.appendingPathComponent("cloud-database.sqlite") ) cloudStoreDescription.type = NSSQLiteStoreType cloudStoreDescription.cloudKitContainerOptions = cloudStoreOptions cloudStoreDescription.setOption(true as NSNumber, forKey: NSPersistentHistoryTrackingKey) cloudStoreDescription.setOption(true as NSNumber, forKey: NSPersistentStoreRemoteChangeNotificationPostOptionKey) return cloudStoreDescription } Any help would be highly appreciated. It seems like iOS bug, because everything seems to be configured properly. I even checked app identifiers if containers are properly assigned. Similar issue when using CloudKit directly (unresolved): https://developer.apple.com/forums/thread/665280

Hello everyone, I'm working on an iOS app that uses CloudKit for data synchronization. I'm encountering an issue where my app can't find the "JournalPrompt" record type in the public database. Here's the relevant code and error messages (I'm using placeholders like [APP_NAME] or [CONTAINER_IDENTIFIER]): private func fetchPromptsFromiCloud() { let container = CKContainer(identifier: "[CONTAINER_IDENTIFIER]") let publicDatabase = container.publicCloudDatabase // Create a predicate to query for the specific record let predicate = NSPredicate(format: "recordID.recordName == %@", "B6663053-FC2E-4645-938B-9FA528D59663") let query = CKQuery(recordType: "JournalPrompt", predicate: predicate) publicDatabase.perform(query, inZoneWith: nil) { [weak self] (records, error) in if let error = error as? CKError { if error.code == .unknownItem { print("JournalPrompt record type does not exist or the specific record was not found in the public database.") } else { print("Error fetching record from iCloud public database: \(error)") } return } guard let record = records?.first else { print("No record found with the specified ID in the public database.") return } print("Found record in public database:") print("Record ID: \(record.recordID.recordName)") print("Text: \(record["text"] as? String ?? "No text")") print("Creation Date: \(record.creationDate ?? Date())") print("Used Count: \(record["usedCount"] as? Int ?? 0)") print("Is Default: \(record["isDefault"] as? Bool ?? false)") } } Error When I run this code, I get the following error: Error fetching record from iCloud public database: <CKError 0x600000c072a0: "Invalid Arguments" (12/1009); "Invalid predicate: recordKey (recordID.recordName) contains invalid characters"> I've also implemented a function to check the CloudKit schema: func checkCloudKitSchema() { checkDatabase(scope: .private) checkDatabase(scope: .public) } private func checkDatabase(scope: CKDatabase.Scope) { let container = CKContainer(identifier: "[CONTAINER_IDENTIFIER]") let database = scope == .private ? container.privateCloudDatabase : container.publicCloudDatabase print("Checking \(scope == .private ? "private" : "public") database") database.fetchAllRecordZones { (zones, error) in if let error = error { print("Error fetching record zones: \(error)") return } print("Available record zones in \(scope == .private ? "private" : "public") database:") zones?.forEach { zone in print("- \(zone.zoneID.zoneName)") } let query = CKQuery(recordType: "JournalPrompt", predicate: NSPredicate(value: true)) database.perform(query, inZoneWith: nil) { (records, error) in if let error = error as? CKError, error.code == .unknownItem { print("JournalPrompt record type does not exist in the \(scope == .private ? "private" : "public") database.") } else if let error = error { print("Error fetching records from \(scope == .private ? "private" : "public") database: \(error)") } else if let records = records, !records.isEmpty { print("JournalPrompt record type exists in the \(scope == .private ? "private" : "public") database.") print("Fetched \(records.count) JournalPrompt records:") for record in records { print("Record ID: \(record.recordID.recordName)") print("Fields:") record.allKeys().forEach { key in print(" - \(key): \(type(of: record[key]))") } print("---") } } else { print("JournalPrompt record type exists in the \(scope == .private ? "private" : "public") database, but no records found.") } } } } When I run this, I get: Checking public database Available record zones in public database: _defaultZone JournalPrompt record type does not exist in the public database. CloudKit Database Setup I've set up my CloudKit Database as follows: And my data model is as follows: Despite this setup, my app can't seem to find or interact with the JournalPrompt record type. I've double-checked that my app's identifier matches the one in the CloudKit dashboard, and I've verified that the record type name is spelled correctly. Questions: Why might my app be unable to find the JournalPrompt record type, even though it's defined in the CloudKit dashboard? Is there anything wrong with my query or error handling that could be causing this issue? Are there any common pitfalls or setup steps I might have missed when integrating CloudKit? Any insights or suggestions would be greatly appreciated. I really appreciate any help you can provide.

I'm building an application with SwiftUI and SwiftData. Up until a couple days ago, everything was working fine. Then, Xcode auto-updated to v16 in the background, and the next time I opened Xcode and tried to build my app it wouldn't build anymore, citing some errors in expanding the SwiftData @Model macro on one of my objects. Attached are the errors specifically, shown where Xcode shows them (in the expanded @Model macro). In text, they are: Instance method 'access(_:keyPath:)' requires that 'Member' conform to 'Observable' Cannot convert value of type 'Risers.Member' to expected argument type 'Member' Instance method 'withMutation(of:keyPath:_:)' requires that 'Member' conform to 'Observable' Cannot convert value of type 'Risers.Member' to expected argument type 'Member' Here is the SwiftData class in full: import SwiftData import SwiftUI @Model class Member: Identifiable, Hashable { var chorus: Chorus? var id = UUID() var firstName: String var lastName: String var fullName: String { "\(firstName) \(lastName)" } var voicePart: Int var voicePartString: String? { chorus?.voicePartType.prettyName(forPart: voicePart) } @Attribute(.externalStorage) var pictureData: Data init(chorus: Chorus? = nil, firstName: String = "", lastName: String = "", voicePart: Int = 1, pictureData: Data = Data()) { self.chorus = chorus self.firstName = firstName self.lastName = lastName self.voicePart = voicePart self.pictureData = pictureData } init(member: Member) { self.chorus = member.chorus self.firstName = member.firstName self.lastName = member.lastName self.voicePart = member.voicePart self.pictureData = member.pictureData } I tried building again on Xcode 15.4, and it still builds successfully there. Xcode 16.1 beta has not made a difference. Is this my fault, or is Xcode 16 broken?

I have an app which uses SwiftData and CloudKit all works fine and well. Now I wanted to implement a feature which lets the user know that there are data incoming from the cloud and they have to wait a little bit for the data to show up. Furthermore my app needs to do some data sanitation when it starts up. This sanitation should only be done after the CloudKit updates are processed. So is there a way that my app can know when CloudKit is doing updates and when it is finished? I was looking for some kind of notification but couldn’t find any info on that. I don’t need to know which data are updated or process the data. I just want to get notified when a sync starts and when it has ended. Actually it would suffice to know when a sync is finished.

Hi, I have a swift data class that has an enum PromptFont as a property. the data class is hosted in CloudKit. upon launch, I started getting this error: below is the property and the enum when I released this app, there was no error, and it was building and running flawlessly. when I build this on a simulator (iPadOS 17.5), it runs just fine

Hi I’m having real problems trying to get a simple “to do” type app working with cloudkit. It works fine with SwiftData but as soon as I add CloudKit I get lots of “container not found errors “ which I think relates to the relationships between my classes. If I strip out the group sort order class it works fine. I’ve stripped the app back to basics to test - I want to be able to add a “task” (task data) to a “group list “ (group data) also also store the position of the task in that list (group sort order) as there may be lots of tasks in a list. The same task could also be in a different group list with a different position in the list (so another entry and value in group sort order) .. why does the following not work?? any help appreciated! //  TaskData.swift //  TaskOutApp // import Foundation import SwiftData `@Model class TaskData: Identifiable, Equatable { var id = UUID() var title: String = "No Title"     var isDone: Bool = false     var isToday: Bool = false     var creationDate: Date = Date()          var doneDate: Date = Date()     var todayDate: Date = Date()     // Use an array of GroupSortOrder to maintain both group and sort order     var groupSortOrders: [GroupSortOrder]? = nil          init(id: UUID = UUID(), title: String = "No Title", isDone: Bool = false, isToday: Bool = false, creationDate: Date = Date(), doneDate: Date = Date(), todayDate: Date = Date(), groupSortOrders: [GroupSortOrder]? = nil) {         self.id = id         self.title = title         self.isDone = isDone         self.isToday = isToday         self.creationDate = creationDate         self.doneDate = doneDate         self.todayDate = todayDate         self.groupSortOrders = groupSortOrders     }          static func currentDateString() -> String {         let formatter = DateFormatter()         formatter.dateStyle = .short         formatter.timeStyle = .short         return formatter.string(from: Date())     }          static func == (lhs: TaskData, rhs: TaskData) -> Bool {         lhs.id == rhs.id     } } @Model class GroupData: Identifiable {     var id = UUID()     var title: String = "no title"     var icon: String = "no icon"     var creationDate: Date = Date()     var task: [TaskData]? = []          init(id: UUID = UUID(), title: String, icon: String, creationDate: Date = Date(), task: [TaskData] = []) {         self.id = id         self.title = title         self.icon = icon         self.creationDate = creationDate         self.task = task     }          static func currentDateString() -> String {         let formatter = DateFormatter()         formatter.dateStyle = .short         formatter.timeStyle = .short         return formatter.string(from: Date())     } } @Model class GroupSortOrder: Identifiable {     var id = UUID()     var group: GroupData? = nil     var sortOrder: Int = 0          init(id: UUID = UUID(), group: GroupData? = nil, sortOrder: Int = 0) {         self.id = id         self.group = group         self.sortOrder = sortOrder     } }`

Hi, after upgrading to Xcode 16.0 I encountered the fact that when loading preview, I get an error: Fatal error: Inverse already set to another relationship - secondAccount - cannot assign to - firstAccount import Foundation import SwiftData import SwiftUI @Model class TransactionModel { @Relationship(inverse: \AccountModel.accountTransactions) var firstAccount: AccountModel? /// <- here @Relationship(inverse: \AccountModel.accountTransactions) var secondAccount: AccountModel? /// <- here @Relationship(inverse: \DebtorModel.transactions) var debtor: DebtorModel? @Relationship(inverse: \CategoryModel.transactions) var category: CategoryModel? init(account: AccountModel? = nil, secondAccount: AccountModel? = nil, debtor: DebtorModel? = nil, category: CategoryModel? = nil) { self.firstAccount = account self.secondAccount = secondAccount self.debtor = debtor self.category = category } } import SwiftData import SwiftUI @Model final public class AccountModel: Identifiable, Hashable { var accountId: UUID = UUID() var accountTransactions: [TransactionModel]? init(id: UUID = UUID()) { self.accountId = id } } Is this really not possible to implement? In Xcode 15, this worked both on the device and in the editor. Thanks!

I'm not entirely sure if this API only shows which fields have changed (e.g., change.updatedAttributes), or if it also provides the updated values for those fields. Ultimately, my goal is to allow users to click in the app to view how a model has mutated over time, and I was wondering if this feature could facilitate that.

Hi everyone, Have anybody faced with Core Data issues, trying to migrate the project to Xcode16 beta 4? We are using transformableAttributeType in some entities, with attributeValueClassName = "[String]" and valueTransformerName = "NSSecureUnarchiveFromData". It is working just fine for years, but now I am trying to run the project from Xcode16 and have 2 issues: in Xcode logs I see warning and error: CoreData: fault: Declared Objective-C type "[String]" for attribute named alertBarChannels is not valid CoreData: Declared Objective-C type "[String]" for attribute named alertBarChannels is not valid periodically the app crashes when we are assigning value to this attribute, with error: Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFConstantString characterAtIndex:]: Range or index out of bounds' Once again, in Xcode 15 it works fine, and it was working for years. Cannot find any information about what was changed in the framework... Thank you in advance for any information, which could clarify what is going on.

I'm running into an odd case where a model's reverse relationship is sometimes not set despite the forward relationship being there. If the app is closed and reopened however, the reverse relationship for previously added data works. For example, given three models Shelf, Item and ItemDetails: @Model final class Shelf { @Relationship(deleteRule: .cascade, inverse: \Item.primaryShelf) var items: [Item] = [] init() {} } @Model final class Item { var primaryShelf: Shelf? var timestamp: Date @Relationship(deleteRule: .cascade, inverse: \ItemDetail.item) public var detail: ItemDetail? init(primaryShelf: Shelf) { self.primaryShelf = primaryShelf self.timestamp = .now } } @Model final class ItemDetail { var item: Item? init(item: Item) { self.item = item } } Now I want to simply create a shelf, some items and some itemdetails. @Test func testRelationshipsThroughInit() async throws { let schema = Schema([Shelf.self, Item.self, ItemDetail.self]) let config = ModelConfiguration(schema: schema, isStoredInMemoryOnly: true) let container = try ModelContainer(for: schema, configurations: [config]) let modelContext = ModelContext(container) let shelf = Shelf() modelContext.insert(shelf) for _ in 0..<10 { let item = Item(primaryShelf: shelf) modelContext.insert(item) let itemDetail = ItemDetail(item: item) modelContext.insert(itemDetail) } try modelContext.save() let fetchDescriptor = FetchDescriptor<Shelf>() let shelves = try modelContext.fetch(fetchDescriptor) // fails with a random number between 0 and 9 typically #expect(shelves.first?.items.count == 10) } There seem to be two ways that this problem goes away. The first is changing the order of properties set in ItemDetail.init() so that the relationship is set after everything else: @Model final class Item { // ... init(primaryShelf: Shelf) { self.timestamp = .now self.primaryShelf = primaryShelf } With this, everything seems to work fine. The other way seems to be manually setting the reverse relationship. So the loop above gets changed to: for _ in 0..<10 { let item = Item(primaryShelf: shelf) modelContext.insert(item) let itemDetail = ItemDetail(item: item) modelContext.insert(itemDetail) // add reverse relationship even though forward was set shelf.items.append(item) } My question is, is this the expected behavior and If so, is there any place this is documented?

Doing a batch delete on a many-to-one relationship seems to throw this error CoreData: error: Unhandled opt lock error from executeBatchDeleteRequest Constraint trigger violation: Batch delete failed due to mandatory OTO nullify inverse on Student/school and userInfo { NSExceptionOmitCallstacks = 1; NSLocalizedFailureReason = "Constraint trigger violation: Batch delete failed due to mandatory OTO nullify inverse on Student/school"; "_NSCoreDataOptimisticLockingFailureConflictsKey" = ( ); } If I try to delete the School in the one-to-many relationship, both the school and the students are deleted as expected. However, If I try to delete all students the error is thrown. I would expect all students to be removed, while keeping the School intact. Do SwiftData support this? import XCTest import SwiftData @Model class School { var name: String @Relationship(deleteRule: .cascade, inverse: \Student.school) var students: [Student] = [] init(name: String) { self.name = name } } @Model class Student { var name: String var school: School? init(name: String) { self.name = name } } final class Test: XCTestCase { func testScenario() throws { let config = ModelConfiguration(isStoredInMemoryOnly: true) let modelContainer = try ModelContainer(for: School.self, Student.self, configurations: config ) let context = ModelContext(modelContainer) context.autosaveEnabled = false let school = School(name: "school") context.insert(school) let student1 = Student(name: "1") let student2 = Student(name: "2") context.insert(student1) context.insert(student2) student1.school = school student2.school = school XCTAssertEqual(school.students.count, 2) XCTAssertEqual(student1.school?.id, school.id) XCTAssertEqual(student2.school?.id, school.id) try context.save() let newContext = ModelContext(modelContainer) // try newContext.delete(model: School.self) // This works try newContext.delete(model: Student.self) // This one fails } }

Given the code below the students array on the school is not being updated. Why? Since the relationship is explicit and non-optional I would expect this to work. import XCTest import SwiftData @Model class School { var name: String @Relationship(deleteRule: .cascade, inverse: \Student.school) var students: [Student] init(name: String, students: [Student]) { self.name = name self.students = students } } @Model class Student { var name: String var school: School init(name: String, school: School) { self.name = name self.school = school } } final class Test: XCTestCase { func testScenario() throws { let modelContainer = try ModelContainer(for: School.self, Student.self ) let context = ModelContext(modelContainer) context.autosaveEnabled = false let school = School(name: "school", students: []) context.insert(school) let student1 = Student(name: "1", school: school) let student2 = Student(name: "2", school: school) context.insert(student1) context.insert(student2) XCTAssertEqual(school.students.count, 2) // XCTAssertEqual failed: ("0") is not equal to ("2") } }

I'm encountering an issue encoding/decoding a custom struct from SwiftData. As it's all happening behind the generated code of SwiftData and a decoder, I'm not really sure what's going on. I have a custom type defined kind of like this: public struct Group<Key: Hashable, Element: Hashable> { private var elementGroups: [Element: Key] private var groupedElements: [Key: [Element]] } In short, it allows multiple elements (usually a string), to be grouped, referenced by some key. I have Codable conformance to this object, so I can encode and decode it. For simplicity, the elementGroups is encoded/decoded, and the groupedElements is rebuilt when decoding. My implementation is similar to this: extension Group: Codable where Key: Codable, Element: Codable { private enum Keys: CodingKey { case groups } public init(from decoder: Decoder) throws { let container = try decoder.container(keyedBy: Keys.self) let decoded = try container.decode([Element: Key].self, forKey: .groups) // Enumerate over the element groups, and populate the list of elements. // var elements: [Key: [Element]] = [:] for group in decoded { elements[group.value] = (elements[group.value] ?? []) + [group.key] } elementGroups = decoded groupedElements = elements } public func encode(to encoder: Encoder) throws { var container = encoder.container(keyedBy: Keys.self) try container.encode(elementGroups, forKey: .groups) } } This works fine when encoding and decoding to JSON, but when I attempt to use this structure as a value within a SwiftData model, then decoding the type crashes my application. @Model final class MyModel { var id: UUID = UUID() var groups: Group<UUID, String> = Group<UUID, String>() init(id: UUID) { self.id = id } } When something attempts to decode the groups property on the MyModel object, it crashes with the following error: Could not cast value of type 'Swift.Optional<Any>' (0x1ed7d0290) to 'Swift.Dictionary<Swift.String, Foundation.UUID>' (0x121fa9448). I would guess that there is a nil value stored for groups in SwiftData, and attempting to decode it to a Group<UUID, String> type is failing. It's odd that it doesn't throw an exception though, and hard crashes. Also, I'm not sure why it's optional, as a value is being written out. Does anyone have any ideas?

Users will receive a unique ID, if a user enters another user's ID they will go to a view where both have access to the information, being able to change, add, delete... (Paired, available on App Store) Public container is not secure, private with ckshare doesn't seem to work for what I would like, plus the content is very confusing I need something that uses native Apple technologies to build this system.