I am trying to extend my PersistedModels like so:
@Versioned(3)
@Model
class MyType {
var name: String
init() { name = "hello" }
}
but it seems that SwiftData's@Model macro is unable to read the properties added by my @Versioned macro. I have tried changing the order and it ignores them regardless. version is not added to schemaMetadata and version needs to be persisted. I was planning on using this approach to add multiple capabilities to my model types. Is this possible to do with macros?
VersionedMacro
/// A macro that automatically implements VersionedModel protocol
public struct VersionedMacro: MemberMacro, ExtensionMacro {
// Member macro to add the stored property directly to the type
public static func expansion(
of node: AttributeSyntax,
providingMembersOf declaration: some DeclGroupSyntax,
in context: some MacroExpansionContext
) throws -> [DeclSyntax] {
guard let argumentList = node.arguments?.as(LabeledExprListSyntax.self),
let firstArgument = argumentList.first?.expression else {
throw MacroExpansionErrorMessage("@Versioned requires a version number, e.g. @Versioned(3)")
}
let versionValue = firstArgument.description.trimmingCharacters(in: .whitespaces)
// Add the stored property with the version value
return [
"public private(set) var version: Int = \(raw: versionValue)"
]
}
// Extension macro to add static property
public static func expansion(
of node: SwiftSyntax.AttributeSyntax,
attachedTo declaration: some SwiftSyntax.DeclGroupSyntax,
providingExtensionsOf type: some SwiftSyntax.TypeSyntaxProtocol,
conformingTo protocols: [SwiftSyntax.TypeSyntax],
in context: some SwiftSyntaxMacros.MacroExpansionContext
) throws -> [SwiftSyntax.ExtensionDeclSyntax] {
guard let argumentList = node.arguments?.as(LabeledExprListSyntax.self),
let firstArgument = argumentList.first?.expression else {
throw MacroExpansionErrorMessage("@Versioned requires a version number, e.g. @Versioned(3)")
}
let versionValue = firstArgument.description.trimmingCharacters(in: .whitespaces)
// We need to explicitly add the conformance in the extension
let ext = try ExtensionDeclSyntax("extension \(type): VersionedModel {}")
.with(\.memberBlock.members, MemberBlockItemListSyntax {
MemberBlockItemSyntax(decl: DeclSyntax(
"public static var version: Int { \(raw: versionValue) }"
))
})
return [ext]
}
}
VersionedModel
public protocol VersionedModel: PersistentModel {
/// The version of this particular instance
var version: Int { get }
/// The type's current version
static var version: Int { get }
}
Macro Expansion:
SwiftData
RSS for tagSwiftData is an all-new framework for managing data within your apps. Models are described using regular Swift code, without the need for custom editors.
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If use a SortDescriptor for a model and sort by some attribute from a relationship, in DEBUG mode it all works fine and sorts. However, in release mode, it is an instant crash.
SortDescriptor(.name, order: .reverse) ---- works
SortDescriptor(.assignedUser?.name, order: .reverse) ---- works in debug but crash in release.
What is the issue here, is it that SwiftData just incompetent to do this?
Hi everyone,
I’m currently developing a SwiftUI app that uses SwiftData with CloudKit sharing enabled. The app works fine on my own Apple ID, and local syncing with iCloud is functioning correctly — but sharing with other Apple IDs consistently fails.
Setup:
SwiftUI + SwiftData using a ModelContainer with .shared configuration
Sharing UI is handled via UICloudSharingController
iCloud container: iCloud.com.de.SkerskiDev.FoodGuard
Proper entitlements enabled (com.apple.developer.icloud-services, CloudKit, com.apple.developer.coredata.cloudkit.containers, etc.)
Automatic provisioning profiles created by Xcode
Error:<CKError 0x1143a2be0: "Bad Container" (5/1014);
"Couldn't get container configuration from the server for container iCloud.com.de.SkerskiDev.FoodGuard">
What I’ve tried:
Verified the iCloud container is correctly created and enabled in the Apple Developer portal
Checked bundle identifier and container settings
Rebuilt and reinstalled the app
Ensured correct iCloud entitlements and signing capabilities
Questions:
Why does CloudKit reject the container for sharing while local syncing works fine?
Are there known issues with SwiftData .shared containers and multi-user sharing?
Are additional steps required (App Store Connect, privacy settings) to allow sharing with other Apple IDs?
Any advice, experience, or example projects would be greatly appreciated. 🙏
Thanks!
Sebastian
I have some models in my app:
[SDPlanBrief.self, SDAirport.self, SDChart.self, SDIndividualRunwayAirport.self, SDLocationBrief.self]
SDLocationBrief has a @Relationship with SDChart
When I went live with my app I didn't have a versioned schema, but quickly had to change that as I needed to add items to my SDPlanBrief Model.
The first versioned schema I made included only the model that I had made a change to.
static var models: [any PersistentModel.Type] {
[SDPlanBrief.self]
}
I had made zero changes to my model container and the whole time, and it was working fine. The migration worked well and this is what I was using:
.modelContainer(for: [SDAirport.self, SDIndividualRunwayAirport.self, SDLocationBrief.self, SDChart.self, SDPlanBrief.self])
I then saw that to do this all properly, I should actually include ALL of my @Models in the versioned schema:
enum AllSwiftDataSchemaV3: VersionedSchema {
static var models: [any PersistentModel.Type] {
[SDPlanBrief.self, SDAirport.self, SDChart.self, SDIndividualRunwayAirport.self, SDLocationBrief.self]
}
static var versionIdentifier: Schema.Version = .init(2, 0, 0)
}
extension AllSwiftDataSchemaV3 {
@Model
class SDPlanBrief {
var destination: String
etc...
init(destination: String, etc...) {
self.destination = destination
etc...
}
}
@Model
class SDAirport {
var catABMinima: String
etc...
init(catABMinima: String etc...) {
self.catABMinima = catABMinima
etc...
}
}
@Model
class SDChart: Identifiable {
var key: String
etc...
var brief: SDLocationBrief? // @Relationship with SDChart
init(key: String etc...) {
self.key = key
etc...
}
}
@Model
class SDIndividualRunwayAirport {
var icaoCode: String
etc...
init(icaoCode: String etc...) {
self.icaoCode = icaoCode
etc...
}
}
@Model
class SDLocationBrief: Identifiable {
var briefString: String
etc...
@Relationship(deleteRule: .cascade, inverse: \SDChart.brief) var chartsArray = [SDChart]()
init(
briefString: String,
etc...
chartsArray: [SDChart] = []
) {
self.briefString = briefString
etc...
self.chartsArray = chartsArray
}
}
}
This is ALL my models in here btw.
I saw also that modelContainer needed updating to work better for versioned schemas. I changed my modelContainer to look like this:
actor ModelContainerActor {
@MainActor
static func container() -> ModelContainer {
let schema = Schema(
versionedSchema: AllSwiftDataSchemaV3.self
)
let configuration = ModelConfiguration()
let container = try! ModelContainer(
for: schema,
migrationPlan: PlanBriefMigrationPlan.self,
configurations: configuration
)
return container
}
}
and I am passing in like so:
.modelContainer(ModelContainerActor.container())
Each time I run the app now, I suddenly get this message a few times in a row:
CoreData: error: Attempting to retrieve an NSManagedObjectModel version checksum while the model is still editable. This may result in an unstable verison checksum. Add model to NSPersistentStoreCoordinator and try again.
I typealias all of these models too for the most recent V3 version eg:
typealias SDPlanBrief = AllSwiftDataSchemaV3.SDPlanBrief
Can someone see if I am doing something wrong here? It seems my TestFlight users are experiencing a crash every now and then when certain views load (I assume when accessing @Query objects). Seems its more so when a view loads quickly, like when removing a subscription view where the data may not have had time to load??? Can someone please have a look and help me out.
Someone smarter than me please tell me if this will work... I want to have an edit screen for a SwiftData class. Auto Save is on, but I want to be able to revert changes. I have read all about sending a copy in, sending an ID and creating a new context without autosave, etc.
What about simply creating a second set of ephemeral values in the actual original model. initialize them with the actual fields. Edit them and if you save changes, migrate that back to the permanent fields before returning.
Don't have to manage a list of @State variables corresponding to every model field, and don't have to worry about a second model context.
Anyone have any idea of the memory / performance implications of doing it this way, and if it is even possible? Does this just make a not quite simple situation even more complicated? Haven't tried yet, just got inspiration from reading some medium content on attributes on my lunch break, and wondering if I am just silly for considering it.
Hi,
I'm getting a very odd error log in my SwiftData setup for an iOS app. It is implemented to support schema migration. When starting the app, it simply prints the following log twice (seems to be dependent on how many migration steps, I have two steps in my sample code):
CoreData: error: Attempting to retrieve an NSManagedObjectModel version checksum while the model is still editable. This may result in an unstable verison checksum. Add model to NSPersistentStoreCoordinator and try again.
(Yes there is a mistyped word "verison", this is exactly the log)
The code actually fully works. But I have neither CloudKit configured, nor is this app in Production yet. I'm still just developing.
Here is the setup and code to reproduce the issue.
Development mac version: macOS 15.5
XCode version: 16.4
iOS Simulator version: 18.5
Real iPhone version: 18.5
Project name: SwiftDataDebugApp
SwiftDataDebugApp.swift:
import SwiftUI
import SwiftData
@main
struct SwiftDataDebugApp: App {
var sharedModelContainer: ModelContainer = {
let schema = Schema([
Item.self,
])
let modelConfiguration = ModelConfiguration(schema: schema, isStoredInMemoryOnly: false, allowsSave: true)
do {
return try ModelContainer(for: schema, migrationPlan: ModelMigraitonPlan.self, configurations: [modelConfiguration])
} catch {
fatalError("Could not create ModelContainer: \(error)")
}
}()
var body: some Scene {
WindowGroup {
ContentView()
}
.modelContainer(sharedModelContainer)
}
}
Item.swift:
import Foundation
import SwiftData
typealias Item = ModelSchemaV2_0_0.Item
enum ModelSchemaV1_0_0: VersionedSchema {
static var versionIdentifier = Schema.Version(1, 0, 0)
static var models: [any PersistentModel.Type] {
[Item.self]
}
@Model
final class Item {
var timestamp: Date
init(timestamp: Date) {
self.timestamp = timestamp
}
}
}
enum ModelSchemaV2_0_0: VersionedSchema {
static var versionIdentifier = Schema.Version(2, 0, 0)
static var models: [any PersistentModel.Type] {
[Item.self]
}
@Model
final class Item {
var timestamp: Date
var tags: [Tag] = []
init(timestamp: Date, tags: [Tag]) {
self.timestamp = timestamp
self.tags = tags
}
}
}
enum ModelMigraitonPlan: SchemaMigrationPlan {
static var schemas: [any VersionedSchema.Type] {
[ModelSchemaV1_0_0.self]
}
static var stages: [MigrationStage] {
[migrationV1_0_0toV2_0_0]
}
static let migrationV1_0_0toV2_0_0 = MigrationStage.custom(
fromVersion: ModelSchemaV1_0_0.self,
toVersion: ModelSchemaV2_0_0.self,
willMigrate: nil,
didMigrate: { context in
let items = try context.fetch(FetchDescriptor<ModelSchemaV2_0_0.Item>())
for item in items {
item.tags = Array(repeating: "abc", count: Int.random(in: 0...3)).map({ Tag(value: $0) })
}
try context.save()
}
)
}
Tag.swift:
import Foundation
struct Tag: Codable, Hashable, Comparable {
var value: String
init(value: String) {
self.value = value
}
static func < (lhs: Tag, rhs: Tag) -> Bool {
return lhs.value < rhs.value
}
static func == (lhs: Tag, rhs: Tag) -> Bool {
return lhs.value == rhs.value
}
func hash(into hasher: inout Hasher) {
hasher.combine(value)
}
}
ContentView.swift:
import SwiftUI
import SwiftData
struct ContentView: View {
@Environment(\.modelContext) private var modelContext
@Query private var items: [Item]
var body: some View {
VStack {
List {
ForEach(items) { item in
VStack(alignment: .leading) {
Text(item.timestamp, format: Date.FormatStyle(date: .numeric, time: .standard))
HStack {
ForEach(item.tags, id: \.hashValue) { tag in
Text("\(tag.value)")
}
}
}
}
.onDelete(perform: deleteItems)
}
Button("Add") {
addItem()
}
.padding(.top)
}
}
private func addItem() {
withAnimation {
let newItem = Item(timestamp: Date(), tags: [Tag(value: "Hi")])
modelContext.insert(newItem)
}
do {
try modelContext.save()
} catch {
print("Error saving add: \(error.localizedDescription)")
}
}
private func deleteItems(offsets: IndexSet) {
withAnimation {
for index in offsets {
modelContext.delete(items[index])
}
}
do {
try modelContext.save()
} catch {
print("Error saving delete: \(error.localizedDescription)")
}
}
}
#Preview {
ContentView()
.modelContainer(for: Item.self, inMemory: true)
}
I hope someone can help, couldn't find anything related to this log at all.
Hi,
I am experiencing main thread freezes from fetching on Main Actor. Attempting to move the function to a background thread, but whenever I reference the TestModel in a nonisolated context or in another model actor, I get this warning:
Main actor-isolated conformance of 'TestModel' to 'PersistentModel' cannot be used in actor-isolated context; this is an error in the Swift 6 language mode
Is there a way to do this correctly?
Recreation, warning on line 13:
class TestModel {
var property: Bool = true
init() {}
}
struct SendableTestModel: Sendable {
let property: Bool
}
@ModelActor
actor BackgroundActor {
func fetch() throws -> [SendableTestModel] {
try modelContext.fetch(FetchDescriptor<TestModel>()).map { SendableTestModel(property: $0.property) }
}
}
The Java Swing and AWT MVC model made it easy to develop complex UIs with data interactions that were not described readily in a nested layer that SwiftUI demands. The implicit update model of SwiftUI greatly complicates development of applications that often requires nested components to have to know too much about other components and other structures than their own, because button events and other user interactions cannot readily alter state across layers. A button push on one component then has to be knowledgable about state in other components which have to have that state represented as @State or @Binding etc. and this causes all kinds of wiring to be spread all over the place rather than have a more centralized "state management function" that would be able to look at the world and synchronize the UIs state across changes.
The fact that the compiler get's lost in the weeds when types and signatures don't match in deeper component structures doesn't help because it makes it doubly hard to do refactoring to raise and lower state management within the structure readily, because the compiler just cannot simply tell you that a function or constructor signature is no longer correct.
Hi,
I'm considering using the new SwiftData class inheritance for a new app I'm building. I have a few questions:
Is it working well enough for production?
I have a number of different object types in my app. Some of them are very similar, and there's always a balance to be struck when it comes to splitting them into different types using class inheritance. Are there some good advice on when to use multiple classes instead of squeezing my object types into a single class?
Is there advice against using class inheritance in multiple levels (3-4)?
Claes
Hi, I’m using SwiftData with an @Observable DatabaseManager class that is shared between my app and a widget. This class is located inside a Swift package and looks roughly like this:
public final class DatabaseManager {
public static let shared = DatabaseManager()
private init() {
let groupID = "group.com.yourcompany.myApp"
let config = ModelConfiguration(groupContainer: .identifier(groupID))
let c = try! ModelContainer(for: MyModel.self, configurations: config)
self.container = c
self.modelContext = c.mainContext
}
public private(set) var container: ModelContainer
public private(set) var modelContext: ModelContext
}
In the main app, I inject the container and context like this:
struct MyApp: App {
var body: some Scene {
WindowGroup {
ContentView()
.modelContainer(DatabaseManager.shared.container)
.modelContext(DatabaseManager.shared.modelContext)
}
}
}
Both the widget and the main app import the same package, and both use DatabaseManager.shared for reading and writing objects.
The problem:
When the widget updates an object using an AppIntent, the change is not reflected in the main app unless I fully terminate and relaunch it. If I just bring the app back to the foreground, it still shows stale data.
Is there a recommended way to make the main app observe or reload SwiftData changes that were made in the widget (via the same shared app group and container)? I’m already using .modelContainer(...) and .modelContext(...) in the app, and everything else works fine — it’s just the syncing that doesn’t happen unless I force-relaunch the app.
Thanks!
Hi, I keep trying to use transformable to store an array of strings with SwiftData, and I can see that it is activating the transformer, but it keeps saying that I am still using NSArray instead of NSData.
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Unacceptable type of value for attribute: property = "category"; desired type = NSData; given type = Swift.__SwiftDeferredNSArray; value = (
yo,
gurt
).'
terminating due to uncaught exception of type NSException
CoreSimulator 1010.10 - Device: iPhone 16 18.0 (6879535B-3174-4025-AD37-ED06E60291AD) - Runtime: iOS 18.0 (22A3351) - DeviceType: iPhone 16
Message from debugger: killed
@Model
class MyModel: Identifiable, Equatable {
@Attribute(.transformable(by: StringArrayTransformer.self)) var category: [String]?
@Attribute(.transformable(by: StringArrayTransformer.self)) var amenities: [String]?
var image: String?
var parentChunck: HenricoPostDataChunk_V1?
init(category: [String]?, amenities: [String]?) {
self.category = category
self.amenities = amenities
}
}
class StringArrayTransformer: ValueTransformer {
override func transformedValue(_ value: Any?) -> Any? {
print(value)
guard let array = value as? [String] else { return nil }
let data = try? JSONSerialization.data(withJSONObject: array, options: [])
print(data)
return data
}
override func reverseTransformedValue(_ value: Any?) -> Any? {
guard let data = value as? Data else { return nil }
let string = (try? JSONSerialization.jsonObject(with: data, options: [])) as? [String]
print(string)
return string
}
override class func transformedValueClass() -> AnyClass {
return NSData.self
}
override class func allowsReverseTransformation() -> Bool {
return true
}
static func register() {
print("regitsering")
ValueTransformer.setValueTransformer(StringArrayTransformer(), forName: .stringArrayTransformerName)
}
}
extension NSValueTransformerName {
static let stringArrayTransformerName = NSValueTransformerName("StringArrayTransformer")
}
I have a SwiftUI document-based app that for the sake of this discussion stores accounting information: chart of accounts, transactions, etc. Each document is backed by a SwiftData DB.
I'd like to incorporate search into the app so that users can find transactions matching certain criteria, so I went to Core Spotlight. Indexing & search within the app seem to work well.
The issue is that Spotlight APIs appear to be App based & not Document based. I can't find a way to separate Spotlight data by document.
I've tried having each document maintain a UUID as a document-specific identifier and include the identifier in every CSSearchableItem. When performing a query I filter the results with CSUserQueryContext.filterQueries that filter by the document identifier. That works to limit results to the specific file for search operations.
Index updates via CSSearchableIndexDelegate.reindex* methods seem to be App-centric. A user may have file #1 open, but the delegate is being asked to update CSSearchableItems for IDs in other files.
Is there a proper way to use Spotlight for in-app search with a document-based app?
Is there a way to keep Spotlight-indexed data local within the app & not make it available across the system? I.e. I'd like to search within the app only. System-level searches should not surface this data.
I am struggling with exactly how to set up SwiftData relationships, beyond the single relationship model...
Let's say I have a school. Each school offers a set of classes. Each class is taught by one teacher and attended by several students. Teachers may teach more than one class, but only at one school. Similarly students may attend more than one class, but only at one school. Classes themselves may be offered at more than one school.
Can someone create a class for School, SchoolClass, Teacher, and Student with id, name, and relationships... I have tried it unsuccessfully about 10 different ways at this point.
My most recent is below... I am struggling getting beyond a school listing in the app, and I'll cross that bridge next. I am just wondering if all the trouble I am having is because I am not smart with the class definitions. And wondering if this is to complex for SwiftData and CoreData is the requirement.
This is not a real app, just my way of really trying to get a handle on Swift Data models and Navigation.
I am very new to Swift, and will take any and all suggestions with enthusiasm! Thanks for taking the time.
import Foundation
import SwiftData
@Model
class School: Identifiable {
var id: UUID = UUID()
var name: String
var mascot: String
var teachers: [Teacher]
var schoolClasses: [SchoolClass]
init (name: String, mascot: String = "", teachers: [Teacher] = [], schoolClasses: [SchoolClass] = []) {
self.name = name
self.mascot = mascot
self.teachers = teachers
}
class SchoolClass: Identifiable {
var id: UUID = UUID()
var name: String
var teacher: Teacher?
var students: [Student] = []
init (name: String, teacher: Teacher? = nil, students: [Student] = []) {
self.name = name
self.teacher = teacher
self.students = students
}
}
class Teacher: Identifiable {
var id: UUID = UUID()
var name: String
var tenured: Bool
var school: School?
var students: [Student] = []
init (name: String, tenured: Bool = false, students: [Student] = []) {
self.name = name
self.tenured = tenured
self.students = students
}
}
class Student: Identifiable {
var id: UUID = UUID()
var name: String
var grade: Int?
var teacher: Teacher?
init (name: String, grade: Int? = nil, teacher: Teacher? = nil) {
self.name = name
self.grade = grade
self.teacher = teacher
}
}
}
Any idea what this message means? I assume it's coming from CloudKit, but the application seems to store and retrieve data properly.
This is not a question but more of a hint where I was having trouble with. In my SwiftData App I wanted to move from Swift 5 to Swift 6, for that, as recommended, I stayed in Swift 5 language mode and set 'Strict Concurrency Checking' to 'Complete' within my build settings.
It marked all the places where I was using predicates with the following warning:
Type '' does not conform to the 'Sendable' protocol; this is an error in the Swift 6 language mode
I had the same warnings for SortDescriptors.
I spend quite some time searching the web and wrapping my head around how to solve that issue to be able to move to Swift 6. In the end I found this existing issue in the repository of the Swift Language https://github.com/swiftlang/swift/issues/68943. It says that this is not a warning that should be seen by the developer and in fact when turning Swift 6 language mode on those issues are not marked as errors.
So if anyone is encountering this when trying to fix all issues while staying in Swift 5 language mode, ignore those, fix the other issues and turn on Swift 6 language mode and hopefully they are gone.
I have an Apple app that uses SwiftData and icloud to sync the App's data across users' devices. Everything is working well. However, I am facing the following issue:
SwiftData does not support public sharing of the object graph with other users via iCloud. How can I overcome this limitation without stopping using SwiftData?
Thanks in advance!
I'm building a SwiftUI app using SwiftData. In my app I have a Customer model with an optional codable structure Contact. Below is a simplified version of my model:
@Model class Customer {
var name: String = ""
var contact: Contact?
init(name: String, contact: Contact? = nil) {
self.name = name
self.contact = contact
}
struct Contact: Codable, Equatable {
var phone: String
var email: String
var allowSMS: Bool
}
}
I'm trying to query all the Customers that have a contact with @Query. For example:
@Query(filter: #Predicate<Customer> { customer in
customer.contact != nil
}) var customers: [Customer]
However no matter how I set the predicate I always get an error:
BugDemo crashed due to an uncaught exception NSInvalidArgumentException. Reason: keypath contact not found in entity Customer.
How can I fix this so that I'm able to filter by contact not nil in my Model?
I tried to use the .deny deleteRule but it seems to have no effect.
The toolbar button adds an item with a relationship to a category to the context. Swiping on the category deletes the category even though an item is referencing the category. There is also no error thrown when saving the context. It is as if the deleteRule was not there.
For other deleteRules like .cascade, the provided sample code works as expected.
import SwiftUI
import SwiftData
@Model
class Category {
var name: String
@Relationship(deleteRule: .deny) var items: [Item] = []
init(name: String) {
self.name = name
}
}
@Model
class Item {
var name: String
var category: Category?
init(name: String, category: Category) {
self.name = name
self.category = category
}
}
struct DenyDeleteRule: View {
@Environment(\.modelContext) private var modelContext
@Query private var categories: [Category]
@Query private var items: [Item]
var body: some View {
List {
Section("Items") {
ForEach(items) { item in
Text(item.name)
}
}
Section("Categories") {
ForEach(categories) { category in
VStack(alignment: .leading) {
Text(category.name).bold()
ForEach(category.items) { item in
Text("• \(item.name)")
}
}
}
.onDelete(perform: deleteCategory)
}
}
.toolbar {
Button("Add Sample") {
let category = Category(name: "Sample")
let item = Item(name: "Test Item", category: category)
modelContext.insert(item)
}
}
}
func deleteCategory(at offsets: IndexSet) {
for index in offsets {
let category = categories[index]
modelContext.delete(category)
do {
try modelContext.save()
} catch {
print(error)
}
}
}
}
#Preview {
NavigationStack {
DenyDeleteRule()
}
.modelContainer(for: [Item.self, Category.self], inMemory: true)
}
I have an iOS app using SwiftData with VersionedSchema. The schema is synchronized with an CloudKit container.
I previously introduced some model properties that I have now removed, as they are no longer needed. This results in the current schema version being identical to one of the previous ones (except for its version number).
This results in the following exception:
'NSInvalidArgumentException', reason: 'Duplicate version checksums across stages detected.'
So it looks like we cannot have a newer schema version with an identical content to an older schema version.
The intuitive way would be to re-add the old (identical) schema version to the end of the "schemas" list property in the SchemaMigrationPlan, in order to signal that it is the newest one, and to add a migration stage back to it, thus:
public enum MySchemaMigrationPlan: SchemaMigrationPlan {
public static var schemas: [any VersionedSchema.Type] {
[
SchemaV100.self,
SchemaV101.self,
SchemaV100.self
]
}
public static var stages: [MigrationStage] {
[
migrateV100toV101,
migrateV101toV100
]
}
However, I am not sure if this is the right way to go, as previously, as I wanted to write unit tests for schema migration and rollback, I tried defining an inverse for each migration stage, so that I could trigger a migration and a rollback from a unit test, which resulted in an exception saying that it is not supported to downgrade a VersionedSchema.
I must admit that I solved the original problem by introducing a dummy model property that I will later remove. What would have been the correct approach?
When I update a variable inside my model that is marked @Transient, my view does not update with this change. Is this normal? If I update a non-transient variable inside the model at the same time that I update the transient one, then both changes are propagated to my view.
Here is an example of the model:
@Model public class WaterData {
public var target: Double = 3000
@Transient public var samples: [HKQuantitySample] = []
}
Updating samples only does not propagate to my view.