Using SwiftData and this is the simplest example I could boil down: @Model final class Item { var timestamp: Date var tag: Tag? init(timestamp: Date) { self.timestamp = timestamp } } @Model final class Tag { var timestamp: Date init(timestamp: Date) { self.timestamp = timestamp } } Notice Tag has no reference to Item. So if I create a bunch of items and set their Tag. Later on I add the ability to delete a Tag. Since I haven't added inverse relationship Item now references a tag that no longer exists so so I get these types of errors: SwiftData/BackingData.swift:875: Fatal error: This model instance was invalidated because its backing data could no longer be found the store. PersistentIdentifier(id: SwiftData.PersistentIdentifier.ID(url: x-coredata://EEC1D410-F87E-4F1F-B82D-8F2153A0B23C/Tag/p1), implementation: SwiftData.PersistentIdentifierImplementation) I think I understand now that I just need to add the item reference to Tag and SwiftData will nullify all Item references to that tag when a Tag is deleted. But, the damage is already done. How can I iterate through all Items that referenced a deleted tag and set them to nil or to a placeholder Tag? Or how can I catch that error and fix it when it comes up? The crash doesn't occur when loading an Item, only when accessing item.tag?.timestamp, in fact, item.tag?.id is still ok and doesn't crash since it doesn't have to load the backing data. I've tried things like just looping through all items and setting tag to nil, but saving the model context fails because somewhere in there it still tries to validate the old value. Thanks!

I have a document based SwiftData app in which I would like to implement a persistent cache. For obvious reasons, I would not like to store the contents of the cache in the documents themselves, but in my app's data directory. Is a use case, in which a document based SwiftData app uses not only the ModelContainers from the currently open files, but also a ModelContainer writing a database file in the app's documents directory (for cache, settings, etc.) supported? If yes, how can you inject two different ModelContexts, one tied to the currently open file and one tied to the local database, into a SwiftUI view?

Hi ! Would anyone know (if possible) how to create backup files to export and then import from the data recorded by SwiftData? For those who wish, here is a more detailed explanation of my case: I am developing a small management software with customers and events represented by distinct classes. I would like to have an "Export" button to create a file with all the instances of these 2 classes and another "Import" button to replace all the old data with the new ones from a previously exported file. I looked for several solutions but I'm a little lost...

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 really don't understand what kind of cyber crap CloudKit is! In macOS, CloudKit basically doesn’t work properly

I'm using NSPersistentCloudKitContainer and in the CloudKit dashboards I have added indexes for all my records modifiedTimestamp queryable, modifiedTimestamp sortable and recordName queryable. But I'm still getting this warning message in the console. <CKError 0x302acf0c0: "Invalid Arguments" (12/2015); server message = "Field 'recordName' is not marked queryable"; op = FF68EFF8D501AED8; uuid = 12C5C84B-EA9B-41A6-AD85-34023827E6FA; container ID = "z.y.x"> error: CoreData+CloudKit: -[NSCloudKitMirroringDelegate _importFinishedWithResult:importer:](1400): <PFCloudKitImporter: 0x30316c1c0>: Import failed with error: <CKError 0x302acf0c0: "Invalid Arguments" (12/2015); server message = "Field 'recordName' is not marked queryable"; op = FF68EFF8D501AED8; uuid = 12C5C84B-EA9B-41A6-AD85-34023827E6FA; container ID = "z.y.x"> error: CoreData+CloudKit: -[NSCloudKitMirroringDelegate recoverFromError:](2312): <NSCloudKitMirroringDelegate: 0x301b1cd20> - Attempting recovery from error: <CKError 0x302acf0c0: "Invalid Arguments" (12/2015); server message = "Field 'recordName' is not marked queryable"; op = FF68EFF8D501AED8; uuid = 12C5C84B-EA9B-41A6-AD85-34023827E6FA; container ID = "z.y.x"> error: CoreData+CloudKit: -[NSCloudKitMirroringDelegate _recoverFromError:withZoneIDs:forStore:inMonitor:](2622): <NSCloudKitMirroringDelegate: 0x301b1cd20> - Failed to recover from error: CKErrorDomain:12 Recovery encountered the following error: (null):0 error: CoreData+CloudKit: -[NSCloudKitMirroringDelegate resetAfterError:andKeepContainer:](612): <NSCloudKitMirroringDelegate: 0x301b1cd20> - resetting internal state after error: <CKError 0x302acf0c0: "Invalid Arguments" (12/2015); server message = "Field 'recordName' is not marked queryable"; op = FF68EFF8D501AED8; uuid = 12C5C84B-EA9B-41A6-AD85-34023827E6FA; container ID = "z.y.x"> error: CoreData+CloudKit: -[NSCloudKitMirroringDelegate _requestAbortedNotInitialized:](2200): <NSCloudKitMirroringDelegate: 0x301b1cd20> - Never successfully initialized and cannot execute request '<NSCloudKitMirroringImportRequest: 0x300738eb0> A3F23AAC-F820-4044-B4B9-28DFAC4DE8D7' due to error: <CKError 0x302acf0c0: "Invalid Arguments" (12/2015); server message = "Field 'recordName' is not marked queryable"; op = FF68EFF8D501AED8; uuid = 12C5C84B-EA9B-41A6-AD85-34023827E6FA; container ID = "z.y.x">

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)

Hi everyone, I am experiencing an iCloud provisioning problem I cannot resolve, and Developer Support has not been able to help. My App ID: com.exaqservices.ArkyvTiles Symptoms: 1. In Xcode (v16.2), enabling iCloud in Signing & Capabilities repeatedly fails with: The app ID does not include the iCloud container. Click Try Again. Clicking Try Again does nothing. The error persists forever. 2. In Certificates, Identifiers & Profiles: • The iCloud capability is enabled for this App ID. • The CloudKit container is selected. • But the portal no longer shows the “iCloud Documents” checkbox, which used to be required for ubiquitous document support. 3. Xcode cannot regenerate provisioning profiles because it claims the App ID is missing the iCloud container — even though the container is attached. 4. Provisioning profiles on the Apple Developer site all appear expired, and new ones do not generate correctly. 5. The App Store Connect interface also does not show an iCloud Services section under App Information → Capabilities as older guides describe. Expected Behavior: Since iCloud and the CloudKit container are enabled on the App ID, Xcode should successfully enable: • com.apple.developer.icloud-services • com.apple.developer.icloud-container-identifiers • com.apple.developer.ubiquity-container-identifiers (if needed) • com.apple.developer.ubiquity-kvstore-identifier Instead, the entitlements never propagate. What I suspect: This seems like an App ID metadata mismatch or a stale backend entry where: • the CloudKit container is attached but the entitlement isn’t linked, • the “iCloud Documents” flag is missing due to a UI transition, • provisioning profiles cannot be regenerated because the App ID is not updating correctly. What I need help with: Can someone from Apple engineering confirm: • Whether my App ID metadata is corrupted, • If entitlements need to be manually refreshed, • Or if the “iCloud Documents” toggle has moved or is no longer exposed? This is blocking development completely — I cannot build, sign, or deploy the app with iCloud. Thank you! Alan Metzger

I've noticed several crashes that look like they're caused by an index out of bound in internal methods of NSFetchedResultsController. This happens while changes are merged from the persistent store container into the view context. Here's an example of the last exception backtrace. Exactly which internal methods that are called in - [NSFetchedResultsController(PrivateMethods) _core_managedObjectContextDidChange:] vary between crash reports but they all end up crashing from _NSArrayRaiseBoundException. The Core Data stack consists of one persistent store, one persistent store coordinator that the view context is set up to automatically merge changes from, and data is saved to disk from background context. persistentContainer.loadPersistentStores(...) viewContext = persistentContainer.viewContext viewContext.automaticallyMergesChangesFromParent = true backgroundContext = persistentContainer.newBackgroundContext() backgroundContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy backgroundClientContext = persistentContainer.newBackgroundContext() backgroundClientContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy Does anyone have any ideas what could be causing this? Thankful for any ideas or advice on how to investigate further.

Hi all, I recently discovered that I forgot to deploy my CloudKit schema changes from development to production - an oversight that unfortunately went unnoticed for 2.5 months. As a result, any data created during that time was never synced to iCloud and remains only in the local CoreData store. Once I pushed the schema to production, CloudKit resumed syncing new changes as expected. However, this leaves me with a gap: there's now a significant amount of data that would be lost if users delete or reinstall the app. Before I attempt to implement a manual backup or migration strategy, I was wondering: Does NSPersistentCloudKitContainer keep track of local changes that couldn't be synced doe to the missing schema and automatically reattempt syncing them now that the schema is live? If not, what would be the best approach to ensure this "orphaned" data gets saved to CloudKit retroactively. Thanks in advance for any guidance or suggestions.

Is it ok to have latency about 4 sec? The amount of downloaded data is less than 1 MB. Maybe I need to setup an index for every field requested?

Am I misunderstanding the expected behavior here, or is there a bug in the behavior of @Attribute(.ephemeral) tagged SwiftData model properties? The documentation for .ephemeral says "Track changes to this property but do not persist". I started using .ephemeral because @Transient was inhibiting SwiftUI from reacting to changes to the property through @Observable. I am updating the value of my @Attribute(.ephemeral) property about once a second and I am seeing corresponding console log output showing the property as part of the generated CKRecord object. I then confirmed in the CloudKit dev portal that the .ephemeral property was added to the Record schema and contains real values. The behavior seems as though the .ephemeral property is being completely ignored. This is observed in a new Xcode project using SwiftData with CloudKit, Xcode 16.2, macOS 15.3.1 and during Build & Run testing on physical devices.

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!

I am working with SwiftData and get the below error. I can't find any documentation on it to see what to fix. Any help would be appreciated. Fatal error: This relationship already has a value but it's not the target:

Definitely one of the stranger quirks of SwiftData I've come across. I have a ScriptView that shows Line entities related to a Production, and a TextEnterScriptView that’s presented in a sheet to input text. I’m noticing that every time I type in the TextEditor within TextEnterScriptView, a new Line shows up in ScriptView — even though I haven’t explicitly inserted it into the modelContext. I'm quite confused because even though I’m only assigning a new Line to a local @State array in TextEnterScriptView, every keystroke in the TextEditor causes a duplicate Line to appear in ScriptView. In other words, Why is SwiftData creating new Line entities every time I type in the TextEditor, even though I’m only assigning to a local @State array and not explicitly inserting them into the modelContext? Here is my minimal reproducible example: import SwiftData import SwiftUI @main struct testApp: App { var body: some Scene { WindowGroup { ContentView() .modelContainer(for: Line.self, isAutosaveEnabled: false) } } } struct ContentView: View { @Environment(\.modelContext) var modelContext @Query(sort: \Production.title) var productions: [Production] var body: some View { NavigationStack { List(productions) { production in NavigationLink(value: production) { Text(production.title) } } .navigationDestination(for: Production.self) { production in ScriptView(production: production) } .toolbar { Button("Add", systemImage: "plus") { let production = Production(title: "Test \(productions.count + 1)") modelContext.insert(production) do { try modelContext.save() } catch { print(error) } } } .navigationTitle("Productions") } } } struct ScriptView: View { @Query private var lines: [Line] let production: Production @State private var isShowingSheet: Bool = false var body: some View { List { ForEach(lines) { line in Text(line.content) } } .toolbar { Button("Show Sheet") { isShowingSheet.toggle() } } .sheet(isPresented: $isShowingSheet) { TextEnterScriptView(production: production) } } } struct TextEnterScriptView: View { @Environment(\.dismiss) var dismiss @State private var text = "" @State private var lines: [Line] = [] let production: Production var body: some View { NavigationStack { TextEditor(text: $text) .onChange(of: text, initial: false) { lines = [Line(content: "test line", production: production)] } .toolbar { Button("Done") { dismiss() } } } } } @Model class Production { @Attribute(.unique) var title: String @Relationship(deleteRule: .cascade, inverse: \Line.production) var lines: [Line] = [] init(title: String) { self.title = title } } @Model class Line { var content: String var production: Production? init(content: String, production: Production?) { self.content = content self.production = production } }

My client is using iCloud Mail with his custom domain and he communicated with many govt organizations which seem to all be using Barracuda Email Protection for their spam prevention. I have properly configured his SPF, DKIM & DMARC DNS records however his emails were still being rejected. (Email header below) I contacted Barracuda support with the email header and they replied saying that the emails were rejected becuase Apple Mail has missing PTR records. I have sent dozens of emails for testing and looking at all their headers I can see (ms-asmtp-me-k8s.p00.prod.me.com [17.57.154.37]) which does not have a PTR record. ----FULL EMAIL HEADER WITH 3RD PARTY DOMAINS REMOVED----- <recipient_email_address>: host d329469a.ess.barracudanetworks.com[209.222.82.255] said: 550 permanent failure for one or more recipients (recipient_email_address:blocked) (in reply to end of DATA command) Reporting-MTA: dns; p00-icloudmta-asmtp-us-west-3a-100-percent-10.p00-icloudmta-asmtp-vip.icloud-mail-production.svc.kube.us-west-3a.k8s.cloud.apple.com X-Postfix-Queue-ID: 8979C18013F8 X-Postfix-Sender: rfc822; sender_email_address Arrival-Date: Thu, 20 Mar 2025 12:30:05 +0000 (UTC) Final-Recipient: rfc822; @****** Original-Recipient: rfc822;recipient_email_address Action: failed Status: 5.0.0 Remote-MTA: dns; d329469a.ess.barracudanetworks.com Diagnostic-Code: smtp; 550 permanent failure for one or more recipients (recipient_email_address:blocked) Return-Path: <sender_email_address> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sender_domain; s=sig1; bh=CyUt/U7mIHwXB5OQctPjRH/OxLH7GsLR54JjGuRkj9Y=; h=From:Message-Id:Content-Type:Mime-Version:Subject:Date:To:x-icloud-hme; b=hwEbggsctiCRlMlEgovBTjB/0sPRCb2k+1wzHRZ2dZNrZdOqvFSNWU+Aki9Bl8nfv eEOoXz5qWxO2b2rEBl08lmRQ3hCyroayIn4keBRrgkxL1uu4zMTaDUHyau2vVnzC3h ZmwQtQxiu7QvTS/Sp8jjJ/niOPSzlfhphqMxnQAZi/jmJGcZPadT8K+7+PhRllVnI+ TElJarN1ORQu+CaPGhEs9/F7AIcjJNemnVg1cude7EUuO9va8ou49oFExWTLt7YSMl s+88hxxGu3GugD3eBnitzVo7s7/O9qkIbDUjk3w04/p/VOJ+35Mvi+v/zB9brpYwC1 B4dZP+AhwJDYA== Received: from smtpclient.apple (ms-asmtp-me-k8s.p00.prod.me.com [17.57.154.37]) by p00-icloudmta-asmtp-us-west-3a-100-percent-10.p00-icloudmta-asmtp-vip.icloud-mail-production.svc.kube.us-west-3a.k8s.cloud.apple.com (Postfix) with ESMTPSA id 8979C18013F8; Thu, 20 Mar 2025 12:30:05 +0000 (UTC) From: Marcel Brunel <sender_email_address> Message-Id: <2E8D69EA-FCA6-4F5D-9D42-22A955C073F6@sender_domain> Content-Type: multipart/alternative; boundary="Apple-Mail=_F9AC7D29-8520-4B25-9362-950CB20ADEC5" Mime-Version: 1.0 (Mac OS X Mail 16.0 (3826.400.131.1.6)) Subject: Re: [EXTERNAL] - Re: Brunel - 2024 taxes Date: Thu, 20 Mar 2025 07:29:27 -0500 In-Reply-To: <SA0PR18MB350300DE7274C018F66EEA24F2D82@SA0PR18MB3503_namprd18_prod_outlook_com> To: Troy Womack <recipient_email_address> References: <SA0PR18MB350314D0B88E283C5C8E1BB6F2DE2@SA0PR18MB3503_namprd18_prod_outlook_com> <9B337A3E-D373-48C5-816F-C1884BDA6F42@sender_domain> <SA0PR18MB350341A7172E8632D018A910F2D82@SA0PR18MB3503_namprd18_prod_outlook_com> <SA0PR18MB350300DE7274C018F66EEA24F2D82@SA0PR18MB3503_namprd18_prod_outlook_com> X-Mailer: Apple Mail (2.3826.400.131.1.6) X-Proofpoint-ORIG-GUID: uqebp2OIbPqBr3dYsAxdFVkCNbM5Cxyl X-Proofpoint-GUID: uqebp2OIbPqBr3dYsAxdFVkCNbM5Cxyl X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1093,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-03-20_03,2025-03-19_01,2024-11-22_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 clxscore=1030 suspectscore=0 mlxlogscore=999 mlxscore=0 phishscore=0 malwarescore=0 spamscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2411120000 definitions=main-2503200077

My question Is there a way to perform an iCloud keychain reset in order to be able to test CKErrorUserDidResetEncryptedDataKey ? I found this section in the CloudKit documentation https://developer.apple.com/documentation/cloudkit/encrypting-user-data#Handle-a-User-Keychain-Reset I want to be prepared for the zoneNotFound / CKErrorUserDidResetEncryptedDataKey case. However, I can't find a way to actually reproduce this error with an iCloud (test-) user and can't find any Apple documentation on how to perform sucha "User Keychain Reset". The only thing that almost looked like it I came across was in the Keychain.app's Settings "Reset Default Keychains…". However, performing this didn't seem to affect the CloudKit data used in our App at all. I've been trying to do this with an Apple account that has 2FA active and a recovery account assigned. We're only targetting >= iOS 18, macOS >= 15.

I'm using NSPersistentCloudKitContainer to save, edit, and delete items, but it only works half of the time. When I delete an item and terminate the app and repoen, sometimes the item is still there and sometimes it isn't. The operations are simple enough: moc.delete(thing) try? moc.save() Here is my DataController. I'm happy to provide more info as needed class DataController: ObservableObject { let container: NSPersistentCloudKitContainer @Published var moc: NSManagedObjectContext init() { container = NSPersistentCloudKitContainer(name: "AppName") container.loadPersistentStores { description, error in if let error = error { print("Core Data failed to load: \(error.localizedDescription)") } } #if DEBUG do { try container.initializeCloudKitSchema(options: []) } catch { print("Error initializing CloudKit schema: \(error.localizedDescription)") } #endif moc = container.viewContext } }

I am using SwiftData with CloudKit to synchronize data across multiple devices, and I have encountered an issue: occasionally, abnormal sync behavior occurs between two devices (it does not happen 100% of the time—only some users have reported this problem). It seems as if synchronization between the two devices completely stops; no matter what operations are performed on one end, the other end shows no response. After investigating, I suspect the issue might be caused by both devices simultaneously modifying the same field, which could lead to CloudKit's logic being unable to handle such conflicts and causing the sync to stall. Are there any methods to avoid or resolve this situation? Of course, I’m not entirely sure if this is the root cause. Has anyone encountered a similar issue?

The stuff I've found by searching has confused me, so hopefully someone can help simplify it for me? I have an app (I use it for logging which books I've given away), and I could either add a bunch of things to the app, or I could have another app (possibly a CLI tool) to generate some reports I'd like.