How do I access the SwiftData container from outside of SwiftUI?

Question

Accessing the container in SwiftUI

I'm setting up the SwiftData container in my App like this:

@main
struct MyApp: App {
    var sharedModelContainer: ModelContainer = {
        do {
            let schema = Schema([MyModel.self])
            return try ModelContainer(
                for: schema,
                configurations: ModelConfiguration(
                    schema: schema,
                    isStoredInMemoryOnly: false
                )
            )
        } catch {
            fatalError("Could not create ModelContainer: \(error)")
        }
    }()
    
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
        .modelContainer(sharedModelContainer)
        .backgroundTask { ... }
    }
}

Accessing the container somewhere else:

I have a .backgroundTask and AppIntent that both access SwiftData.

Edit: for the .backgroundTask - as Joakim pointed out - I can simply pass-in the container:

.backgroundTask(.appRefresh("myTaskId")) {
    let container = await sharedModelContainer
    // ...
}

For the AppIntent I'm doing this:

struct MyAppIntent: AppIntent {
    // ...

    func perform() async throws -> some IntentResult {
          let schema = Schema([MyModel.self])
          let modelContainer = try ModelContainer(
              for: schema,
              configurations: ModelConfiguration(
                schema: schema,
                isStoredInMemoryOnly: false
              )
          )
           let task = Task.detached {
              let actor = MyActor(modelContainer: modelContainer)
              try await actor.doSomething()
          }
          try await task.value
          return .result()
    }
}

Is that the correct way of accessing the ModelContainer from other places?

Looking at the documentation it seems to me like it is, but maybe I'm missing something.

---

The issue is when I open the App after having run the Shortcut or the background task and perform something that creates a relationship for a new model that just got inserted, the App crashes and I'm getting this error:

"Unacceptable type of value for to-one relationship: property = "MyModel"; desired type = NSManagedObject; given type = NSManagedObject;