ios CoreData, After returning from background crashes with: CoreData: warning: Multiple NSEntityDescriptions claim

I am seeing a crash in core data that only happens after returning from the background. It works fine until I put the app in the background and return to foreground

The error is

[error] warning: Multiple NSEntityDescriptions claim the NSManagedObject subclass 'CDChatMessage' so +entity is unable to disambiguate.  CoreData: warning: Multiple NSEntityDescriptions claim the NSManagedObject subclass 'CDChatMessage' so +entity is unable to disambiguate.  [error] warning:     'CDChatMessage' (0x2810a8a50) from NSManagedObjectModel (0x280485bd0) claims 'CDChatMessage'.  

I have a singleton which handles the coredata functionality, My initialisation code for the CoreData in that singleton is:

    override init() {          super.init()                    let bundle = Bundle(for: CoreDataStack.self)          guard let url = bundle.url(forResource: "Testing", withExtension: "momd"),                let model = NSManagedObjectModel(contentsOf: url) else {              fatalError()          }          self.storeCoordinator = NSPersistentStoreCoordinator(managedObjectModel: model)          self.context = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)          self.context?.mergePolicy = NSMergePolicy(merge: NSMergePolicyType.mergeByPropertyObjectTrumpMergePolicyType)          self.context?.persistentStoreCoordinator = self.storeCoordinator                    let urls = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)          let docURL = urls[urls.endIndex-1]            let storeURL = docURL.appendingPathComponent(kDatabaseName)          do {              try storeCoordinator?.addPersistentStore(ofType: NSSQLiteStoreType, configurationName: nil, at: storeURL, options: nil)          } catch {              fatalError("Error migrating store: \(error)")          }      }  

And the place where it works until I enter the background and then foreground is:

    public func loadManaged<T: NSManagedObject>(forPredicate predicate: NSPredicate) -> [T] {          let request: NSFetchRequest<T> = T.fetchRequest() as! NSFetchRequest<T>          request.entity = T.entity()          request.predicate = predicate          do {              return try context?.fetch(request) ?? []          } catch {              return [T]()          }      }  

(It crashes on the context?.fetch call)

What happens when it enters the background/foreground that causes the multiple NSEntityDescriptions? And am I doing something wrong in the code above, or is there something I can do differently to fix this crash?

https://stackoverflow.com/questions/66947669/ios-coredata-after-returning-from-background-crashes-with-coredata-warning-m April 05, 2021 at 10:39AM