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! 😊
iCloud & Data
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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?
In a document based SwiftData app for macOS, how do you go about opening a (modal) child window connected to the ModelContainer of the currently open document?
Using .sheet() does not really result in a good UX, as the appearing view lacks the standard window toolbar.
Using a separate WindowGroup with an argument would achieve the desired UX. However, as WindowGroup arguments need to be Hashable and Codable, there is no way to pass a ModelContainer or a ModelContext there:
WindowGroup(id: "myWindowGroup", for: MyWindowGroupArguments.self) { $args in
ViewThatOpensInAWindow(args: args)
}
Is there any other way?
Hi,
I’m completely stuck with a very strange CloudKit problem that started recently and has now killed all iCloud sync for a live production app.
What is happening
Production container: iCloud.gainzCloud (created ~11 months ago, has been working perfectly until now)
In Xcode 26.0 (17A321):
→ Signing & Capabilities → iCloud is enabled
→ Container correctly shows as iCloud.gainzCloud
→ App builds and runs on device/simulator with zero provisioning or container errors
CloudKit Dashboard (https://icloud.developer.apple.com/dashboard/): completely blank – “No containers found”
Result: CloudKit sync is dead for every user (development + production environments)
What I know for sure
Apple Developer Support confirmed the container iCloud.gainzCloud still exists and is correctly attached to my Team ID on their backend
Personal iCloud (Mail, Notes, Photos, etc.) syncs perfectly on the same Mac / same Apple ID under macOS Tahoe 26.1
I have NOT changed the password on either the Apple ID or the Developer Program account
New containers I create appear in Xcode but never show up in the Dashboard
Environment
macOS Tahoe 26.1 (latest)
Xcode Version 26.0 (17A321)
Has anyone on the new Tahoe/Xcode 26 releases seen the CloudKit Dashboard suddenly go completely empty while Xcode still “sees” the container just fine?
Any known trick to force the dashboard to re-index containers or clear whatever cache is broken?
Thanks a lot in advance – this is blocking all iCloud functionality for a released app with active users.
Topic:
App & System Services
SubTopic:
iCloud & Data
My app uses iCloud to let users sync their files via their private iCloud Drive, which does not use CloudKit.
FileManager.default.url(forUbiquityContainerIdentifier: nil)?.appending(component: "Documents")
I plan to transfer my app to another developer account, but I'm afraid it will affect the access of the app to the existing files in that folder. Apple documentation doesn't mention this case.
Has anyone done this before and can confirm if the app will continue to work normally after transferring?
Thanks
I'm trying to build a custom FetchRequest that I can use outside a View. I've built the following ObservableFetchRequest class based on this article: https://augmentedcode.io/2023/04/03/nsfetchedresultscontroller-wrapper-for-swiftui-view-models
@Observable @MainActor class ObservableFetchRequest<Result: Storable>: NSObject, @preconcurrency NSFetchedResultsControllerDelegate {
private let controller: NSFetchedResultsController<Result.E>
private var results: [Result] = []
init(context: NSManagedObjectContext = .default, predicate: NSPredicate? = Result.E.defaultPredicate(), sortDescriptors: [NSSortDescriptor] = Result.E.sortDescripors) {
guard let request = Result.E.fetchRequest() as? NSFetchRequest<Result.E> else {
fatalError("Failed to create fetch request for \(Result.self)")
}
request.predicate = predicate
request.sortDescriptors = sortDescriptors
controller = NSFetchedResultsController(fetchRequest: request, managedObjectContext: context, sectionNameKeyPath: nil, cacheName: nil)
super.init()
controller.delegate = self
fetch()
}
private func fetch() {
do {
try controller.performFetch()
refresh()
}
catch {
fatalError("Failed to fetch results for \(Result.self)")
}
}
private func refresh() {
results = controller.fetchedObjects?.map { Result($0) } ?? []
}
var predicate: NSPredicate? {
get {
controller.fetchRequest.predicate
}
set {
controller.fetchRequest.predicate = newValue
fetch()
}
}
var sortDescriptors: [NSSortDescriptor] {
get {
controller.fetchRequest.sortDescriptors ?? []
}
set {
controller.fetchRequest.sortDescriptors = newValue.isEmpty ? nil : newValue
fetch()
}
}
internal func controllerDidChangeContent(_ controller: NSFetchedResultsController<any NSFetchRequestResult>) {
refresh()
}
}
Till this point, everything works fine.
Then, I conformed my class to RandomAccessCollection, so I could use in a ForEach loop without having to access the results property.
extension ObservableFetchRequest: @preconcurrency RandomAccessCollection, @preconcurrency MutableCollection {
subscript(position: Index) -> Result {
get {
results[position]
}
set {
results[position] = newValue
}
}
public var endIndex: Index { results.endIndex }
public var indices: Indices { results.indices }
public var startIndex: Index { results.startIndex }
public func distance(from start: Index, to end: Index) -> Int {
results.distance(from: start, to: end)
}
public func index(_ i: Index, offsetBy distance: Int) -> Index {
results.index(i, offsetBy: distance)
}
public func index(_ i: Index, offsetBy distance: Int, limitedBy limit: Index) -> Index? {
results.index(i, offsetBy: distance, limitedBy: limit)
}
public func index(after i: Index) -> Index {
results.index(after: i)
}
public func index(before i: Index) -> Index {
results.index(before: i)
}
public typealias Element = Result
public typealias Index = Int
}
The issue is, when I update the ObservableFetchRequest predicate while searching, it causes a Index out of range error in the Collection subscript because the ForEach loop (or a List loop) access a old version of the array when the item property is optional.
List(request, selection: $selection) { item in
VStack(alignment: .leading) {
Text(item.content)
if let information = item.information { // here's the issue, if I leave this out, everything works
Text(information)
.font(.callout)
.foregroundStyle(.secondary)
}
}
.tag(item.id)
.contextMenu {
if Item.self is Client.Type {
Button("Editar") {
openWindow(ClientView(client: item as! Client), id: item.id!)
}
}
}
}
Is it some RandomAccessCollection issue or a SwiftUI bug?
Greetings i have an app that uses three different SwiftData models and i want to know what is the best way to use the them accross the app. I though a centralized behaviour and i want to know if it a correct approach.First let's suppose that the first view of the app will load the three models using the @Enviroment that work with @Observation. Then to other views that add data to the swiftModels again with the @Environment. Another View that will use the swiftData models with graph and datas for average and min and max.Is this a corrent way? or i should use @Query in every view that i want and ModelContext when i add the data.
@Observable
class CentralizedDataModels {
var firstDataModel: [FirstDataModel] = []
var secondDataModel: [SecondDataModel] = []
var thirdDataModel: [ThirdDataModel] = []
let context: ModelContext
init(context:ModelContext) {
self.context = context
}
}
I'm building a photo editing app with a token-based subscription system using RevenueCat and StoreKit. Users purchase subscriptions that grant tokens for AI generations. There are no user accounts, the app is fully anonymous.
Currently, I generate an anonymous account ID via RevenueCat SDK and store it in iCloud Keychain. This allows users on the same iCloud account to restore both their subscription and token balance across devices. However, users on a different iCloud account can restore their subscription via Apple, but their token balance is lost because there's no way to link the anonymous IDs.
The problem is that if a user switches iCloud accounts or gets a new device without the same iCloud, their purchased tokens are orphaned. The subscription restores fine through Apple, but the token balance tied to the old anonymous ID becomes inaccessible.
I have a few constraints: no user accounts, no email or phone sign-in, must work across devices owned by the same person, and must comply with App Store guidelines.
My questions are: Is iCloud Keychain the right tool for this, or is there a better approach? Would CloudKit with an anonymous record zone be more appropriate? Are there any recommended patterns for persisting consumable balances tied to anonymous users across device migrations?
Any guidance would be appreciated.
Topic:
App & System Services
SubTopic:
iCloud & Data
What have people's experience with converting locally stored app data to a more browser based accessible format? Firebase seems expensive, Subabase a bit more challenging, and CloudKit too restrictive.
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...
Greetings my fellow engineers,
I use SwiftData in my iOS app. The schema is unversioned and consists of a single model. I've been modifying the model for almost two years now and relying on automatic database migrations. I had no problems for all that time, but now trying to add a property to the model or even remove a property from the model results in an error which seems like SwiftData is no longer capable of performing an automatic migration.
The log console has things like the following:
CoreData: error: NSUnderlyingError : Error Domain=NSCocoaErrorDomain Code=134190 "(null)" UserInfo={reason=Each property must have a unique renaming identifier}
CoreData: error: reason : Can't find or automatically infer mapping model for migration
CoreData: error: storeType: SQLite
CoreData: error: configuration: default
CoreData: annotation: options:
CoreData: annotation: NSMigratePersistentStoresAutomaticallyOption : 1
CoreData: annotation: NSInferMappingModelAutomaticallyOption : 1
CoreData: annotation: NSPersistentStoreRemoteChangeNotificationOptionKey : 1
CoreData: annotation: NSPersistentHistoryTrackingKey : 1
CoreData: error: <NSPersistentStoreCoordinator: 0x7547b5480>: Attempting recovery from error encountered during addPersistentStore: 0x753f8d800 Error Domain=NSCocoaErrorDomain Code=134140 "Persistent store migration failed, missing mapping model."
Have you ever encountered such an issue? What are my options?
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.
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?
Topic:
App & System Services
SubTopic:
iCloud & Data
Testing Environment: iOS 18.4.1 / macOS 15.4.1
I am working on an iOS project that aims to utilize the user's iCloud Drive documents directory to save a specific directory-based file structure. Essentially, the app would create a root directory where the user chooses in iCloud Drive, then it would populate user generated files in various levels of nested directories.
I have been attempting to use NSMetadataQuery with various predicates and search scopes but haven't been able to get it to directly monitor changes to files or directories that are not in the root directory.
Instead, it only monitors files or directories in the root directory, and any changes in a subdirectory are considered an update to the direct children of the root directory.
Example
iCloud Drive Documents (Not app's ubiquity container)
User Created Root Directory (Being monitored)
File A
Directory A
File B
An insertion or deletion within Directory A would only return a notification with userInfo containing data for NSMetadataQueryUpdateChangedItemsKey relating to Directory A, and not the file or directory itself that was inserted or deleted. (Query results array also only contain the direct children.)
I have tried all combinations of these search scopes and predicates with no luck:
query.searchScopes = [
rootDirectoryURL,
NSMetadataQueryUbiquitousDocumentsScope,
NSMetadataQueryAccessibleUbiquitousExternalDocumentsScope,
]
NSPredicate(value: true)
NSPredicate(format: "%K LIKE '*.md'", NSMetadataItemFSNameKey)
NSPredicate(format: "%K BEGINSWITH %@", NSMetadataItemPathKey, url.path(percentEncoded: false))
I do see these warnings in the console upon starting my query:
[CRIT] UNREACHABLE: failed to get container URL for com.apple.CloudDocs
[ERROR] couldn't fetch remote operation IDs: NSError: Cocoa 257 "The file couldn’t be opened because you don’t have permission to view it."
"Error returned from daemon: Error Domain=com.apple.accounts Code=7 "(null)""
But I am not sure what to make of that, since it does act normally for finding updates in the root directory.
Hopefully this isn't a limitation of the API, as the only alternative I could think of would be to have multiple queries running for each nested directory that I needed updates for.
Topic:
App & System Services
SubTopic:
iCloud & Data
Tags:
Files and Storage
iCloud Drive
Foundation
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 have a Package.swift file that builds and runs from Xcode 15.2 without issue but fails to compile when built from the command line ("swift build"). The swift version is 6.0.3. I'm at wits end trying to diagnose this and would welcome any thoughts.
The error in question is
error: external macro implementation type 'SwiftDataMacros.PersistentModelMacro' could not be found for macro 'Model()'; plugin for module 'SwiftDataMacros' not found
The code associated with the module is very vanilla.
import Foundation
import SwiftData
@Model
public final class MyObject {
@Attribute(.unique) public var id:Int64
public var vertexID:Int64
public var updatedAt:Date
public var codeUSRA:Int32
init(id:Int64, vertexID:Int64, updatedAt:Date, codeUSRA:Int32) {
self.id = id
self.vertexID = vertexID
self.updatedAt = updatedAt
self.codeUSRA = codeUSRA
}
public static func create(id:Int64, vertexID:Int64, updatedAt:Date, codeUSRA:Int32) -> MyObject {
MyObject(id: id, vertexID: vertexID, updatedAt: updatedAt, codeUSRA: codeUSRA)
}
}
Thank you.
Hi forum! I’m currently following a series of videos about SwiftData. In the WWDC23 Build an app with SwiftData video, it mentions that you can follow up with a demo project. However, I’m encountering an issue (at least in my case) where there’s no link on the entire page to download the project. I can download the video and other resources (even using the Developer’s App), but there’s no link for the project. Does anyone else face this issue? Is it possible that the project has been removed? I’m using my developer (single user) account, by the way. Any guidance would be greatly appreciated!
Hey guys, I'm developing a Swift app, using iCloud to store some data in Containers, and the new Containers I created are iCloud.com.xxx.dev . Therefore, there is a storage called dev in Settings -> icloud -> Manage Account Storage. Currently, the app is still under development and has not been released to the Appstore.
My question: Settings -> icloud -> Manage Account Storage does not display my app name and icon, but only the suffix of the Containers id. Will this change after it is released to the Appstore? Are there any other control methods? Thank you
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,
In our app, we’ve modeled our schema using inheritance introduced in iOS 26.0, and we’re implementing SwiftData History to re-fetch models only when necessary.
@Model public class Transaction {
@Attribute(.preserveValueOnDeletion)
public var date: Date = Date()
public var amount: Double = 0
public var memo: String?
}
@Model public final class Spending: Transaction {
public var installmentIndex: Int = 1
public var installment: Int = 1
public var installmentID: UUID?
}
If data has been deleted from database, we need to check a date property to determine whether to re-fetch datas.
To do this, we added the preserveValueOnDeletion attribute to date property so we could retrieve it from the History tombstone value.
However, after adding this attribute, a crash occurs. There is a console log
Could not cast value of type 'Swift.ReferenceWritableKeyPath<Shared.ModelSchemaV5.Transaction, Foundation.Date>' (0x106bf8328) to 'Swift.PartialKeyPath<Shared.ModelSchemaV5.Spending>' (0x1094f21d8).
and error log attached
StrictMoneyChecking-2025-11-07-105108.txt
I also tried this in the recent SampleTrip app, and fetching all history after a deletion causes the same crash.
Is this issue currently being worked on or under investigation?