Has anyone successfully used NSStagedMigrationManager?

I've come back to my test a couple of times over the last two months, and I'm still seeing the same exact issue in the final released version of Xcode 15. I sure wish I knew whether this was actually a bug, or whether I'm using this (under-documented!) API incorrectly.

Because the only sample code I can find anywhere (from the WWDC presentation) uses NSPersistentContainer, I thought I'd try re-writing my tests to do the same, rather than creating the NSPersistentStoreCoordinator directly.

Unfortunately, while that initially appears to work — loadPersistentStores(_:) calls its completion handler with a nil error — it appears that it's failing silently somewhere along the way. The container's persistentStoreCoordinator.persistentStores is empty, and attempting to save changes to its viewContext throws "This NSPersistentStoreCoordinator has no persistent stores (unknown). It cannot perform a save operation."

Same here, my XCode Version is 15.0.1

After 3 months, did you find the solution?

Have you found a solution to this problem?

My schema has 2 versions, and I want to migrate with a custom stage migration. My app crashes at launch with the following error: Thread 1: "Duplicate version checksums across stages detected.".

I filed feedback #FB13647876 and request a technical support.

I attempted to create a model by directly accessing the Managed Object Model (MOM), and the code ran successfully. I also completed the migration process. The implementation is somewhat obscure, and I believe Apple's main purpose in providing this migration method for Core Data is to offer a foundational implementation for phased migrations in SwiftData.

guard let momdURL = Bundle.main.url(forResource: "Model", withExtension: "momd") else { fatalError() }
let model1URL = momdURL.appending(component: "Model.mom")
let model2URL = momdURL.appending(component: "Model 2.mom")
guard let model1 = NSManagedObjectModel(contentsOf: model1URL) else { fatalError() }
guard let model2 = NSManagedObjectModel(contentsOf: model2URL) else { fatalError() }

let v1ModelChecksum = model1.versionChecksum
let v1ModelReference = NSManagedObjectModelReference(model: model1, versionChecksum: v1ModelChecksum)

let v2ModelChecksum = model2.versionChecksum
let v2ModelReference = NSManagedObjectModelReference(model: model2, versionChecksum: v2ModelChecksum)

let customStage = NSCustomMigrationStage(
  migratingFrom: v1ModelReference,
  to: v2ModelReference
)

let migrationManager = NSStagedMigrationManager([customStage])

let description = container.persistentStoreDescriptions.first
description?.setOption(migrationManager, forKey: NSPersistentStoreStagedMigrationManagerOptionKey)

and I have update my topic about staged migration of Core Data. https://fatbobman.com/en/posts/what-s-new-in-core-data-in-wwdc23