SwiftData ModelContainer can not be created in iOS 17.4 Beta

Question

Created Feb ’24

Replies 7

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I have an app in the app store which is working fine. Some users reported that they have app crashing when they are using iOS 17.4 beta. I could recreate the issue and it is happening when ModelContainer is crerated. This code..

do {
                let configuration = ModelConfiguration(for: MyTodo.self, isStoredInMemoryOnly: false)
                modelContainer = try ModelContainer(for: MyTodo.self, configurations: configuration)

            } catch {
                fatalError("Failed to load model container.\(error)")
            }

is throwing this error message:

Fatal error: Failed to load model container.SwiftDataError(_error: SwiftData.SwiftDataError._Error.loadIssueModelContainer)

Answered by mikrasya in 780347022

It seems for whatever reason inverse relationship needs to be explicitly defined. Change from this:

@Relationship(deleteRule: .cascade) var tasks: [MyTask]? = []

to

@Relationship(deleteRule: .cascade, inverse: \MyTask.todo) var tasks: [MyTask]? = []

has solved the crash issue. Works both in iOS 17.3 and 17.4.

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Answer 1

mikrasya OP

Feb ’24

My model do not have any @Attribute(.unique) All properties have default values Relationships are marked as optional App is using CloudKit for iCloud syncronization

A brandnew app with the same model does not have this issue. When I uncheck "CloutKit" in Signing & Capabilities, the app launch normally.

0

Answer 2

mikrasya OP

Feb ’24

Widget can obtain the data without error/crash from modelContainer using this code:

        guard let modelContainer = try? ModelContainer(for: MyTodo.self) else {
            return []
        }

0

Answer 3

mikrasya OP

Feb ’24

I have now identified that this issue is happening due to Relationships in my model. My MyToDo has task defined like this:

@Relationship(deleteRule: .cascade) var tasks: [MyTask]? = []

and MyTask has reference back as following:

var todo: MyTodo?

Both of them are optional as required for CloudKit. This model can be read in iOS 17.3, but in 17.4 beta, it crashes!

0

Answer 4

mikrasya OP

Feb ’24

Accepted Answer

It seems for whatever reason inverse relationship needs to be explicitly defined. Change from this:

@Relationship(deleteRule: .cascade) var tasks: [MyTask]? = []

to

@Relationship(deleteRule: .cascade, inverse: \MyTask.todo) var tasks: [MyTask]? = []

has solved the crash issue. Works both in iOS 17.3 and 17.4.

0

Answer 5

jhokit OP

Mar ’24

Thanks @mikrasya for documenting this. I have the same problem, but already have inverses set. Removing inverses didn't help either. (I've read that inverses aren't necessary when using iCloud, that they are automatically inferred). 🤷🏼‍♂️

I sent in a question to Developer Tech Support, and will repeat any solution here for you and the other five who've marked your posting with "Same Here".

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Answer 6

funcmakerDan OP

Mar ’24

I tried creating a new app, with a new container, using the Xcode 'stock' Item ie; item.timestamp. I tried it in a 17.4 simulator and iPhone with 17/4. Both failed for the same reason as noted by the OP. Fatal error: Could not create ModelContainer: SwiftDataError(_error: SwiftData.SwiftDataError._Error.loadIssueModelContainer). I also have a "Live" App that is not loading because of 17.4. Also... I have played with the relationships as described in the posts above and nothing worked. Again - Apple's stock, stripped down, Items app is failing.???

Update: As for my app... The culprit was that I had added modelContext into the environment using both an @Environment call and .modelContainer on WindowGroup. By the way, this worked prior to 17.4. The solution was to remove : @Environment(.modelContext) private var modelContext.

As for the 'stock app', I discovered that the issue was that timestamp is not marked optional so it fails. Marking it optional? and then providing ?? Date.now values where needed solved the problem.

1

Answer 7

robotmay OP

May ’24

In case anyone else stumbles across this, I found the following syntax resolved the error for me:

    @Relationship(inverse: \Item.category)
    var items: [Item]? = []

    var category: ItemCategory?

Seems to work so I guess it's correct? 🤷

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