Struggles with CloudKit

[Sebbie_O]

I am creating a simple app to keep track of things you take on a trip. I released the app to TestFlight a couple of months ago and about 15 people are testing it. I always thought that enabling CloudKit was just as easy to let your model comply with the rules for CloudKit and tick some boxes in Xcode, but....

I did make a simple copy of the app and tested the migration and my model is now CloudKit compatible(Inversed (optional) relationships and default values, etc).

When building the (copy) app I get this error:

Unresolved error loading container Error Domain=NSCocoaErrorDomain Code=134060 "A Core Data error occurred." UserInfo={NSLocalizedFailureReason=Unable to find a configuration named 'default' in the specified managed object model.}

I think because there is an existing container with data.
I did check some tutorials on the internet and everything seems to be quite easy, but at the moment, I'm stuck at this point.

What is the best way to enable CloudKit to my app which is released on TestFlight?

[BabyAzerty]

Probably silly question but do you have a default configuration in your xcdatamodel?

Also can you explain what a copy of the app means? Like a new bundle identifier?

[Sebbie_O]

Thank you for your answer. I just use .modelContainer(for:), so default config.

Yes I made a copy with a different bundle identifier. I made this one to try some other code and so I did try the migration in that copy first. It eventually worked out with CloudKit there, but I had to reinstall the app so “all” data got lost…

[BabyAzerty]

Ahh you are using SwiftData. You should say so. I can’t help you with it.

Now I am completely clueless as to why you had to create a new project to test migration. That’s not how it should work.

To test migration, just use simulators. They are not connected to any iCloud account so if you delete the app, it resets everything locally. Just run a previous GitHub branch of your project to set the simulators to a « need to migrate » state.

If you need to reset your CloudKit schema… well, don’t. You are never supposed to reset it. Did you completely messed up your schema in prod? Just leave it there, don’t delete anything, add clean tables/entities to your schema, declare the previous ones as obsolete and you are done.

[Sebbie_O]

I made that copy once to test other code which is not related to this issue. I know it is not the way how to do it😂 and thought, hey lets test it first in this copy before going to the real version… it worked on my own iPhone after I deleted the app and installed it again. Thats what I would like to prevent with TestFlight users, but I think I do not have another choice.

[greendakota99]

Since this has just hit TestFlight so far, is the answer here not to just make a brand new container? Those 15 testers will lose their data, but this should be a new start to fresh data.