No NSEntityDescriptions in any model claim the NSManagedObject subclass

Question

I am new to CoreData and I'm trying to create a caching mechanism wherein after parsing objects from the API, I save them to the data model then fetch it again to show it on the tableview. I'm trying to fetch it using NSFetchedResultsController. Upon initialization of the NSFetchedResultsController, I'm encountering this runtime exception:

2018-12-09 15:03:20.493509+0800 [5184:148001] [error] error:  No NSEntityDescriptions in any model claim the NSManagedObject subclass  'Product' so +entity is confused.  Have you loaded your  NSManagedObjectModel yet ? CoreData: error: No NSEntityDescriptions in any model claim the  NSManagedObject subclass 'Product' so +entity is confused.  Have you  loaded your NSManagedObjectModel yet ? 2018-12-09 15:03:20.493718+0800[5184:148001] [error] error: +  [Product entity] Failed to find a unique match for an  NSEntityDescription to a managed object subclass CoreData: error: +[Product entity] Failed to find a unique match for an  NSEntityDescription to a managed object subclass 

What could be the reason why?

Answer 1

If you ever encounter an issue similar to this using SwiftUI, you can try changing the entity's class module from Global Namespace to Current Product Module.

Go to your xcdatamodeld file and select the problematic entity. Then in the data model inspector, change the Module field from the default Global namespace to available value "Current Product Module" by clicking on the arrow at the right of the field.

This allowed my app to compile without encountering the error.

Answer 2

My experience:

The entity class was missing the @objc(Person) line above the class name. I do have more classes that are working without this line but only when creating this specific entity, I have got this error.

@objc(Person) public class Person: NSManagedObject {  }