Core Data & Xcode 11: Please switch to using "NSSecureUnarchiveFromData" or a subclass of NSSecureUnarchiveFromDataTransformer

Question

Just moved to Xcode 11 and getting the following crash at launch:

CoreData: fault: One or more models in this application are using transformable properties with transformer names that are either unset, or set to NSKeyedUnarchiveFromDataTransformerName. Please switch to using "NSSecureUnarchiveFromData" or a subclass of NSSecureUnarchiveFromDataTransformer instead. At some point, Core Data will default to using "NSSecureUnarchiveFromData" when nil is specified, and transformable properties containing classes that do not support NSSecureCoding will become unreadable.

CoreData: warning: Property 'color' on Entity 'Group' is using nil or an insecure NSValueTransformer. Please switch to using "NSSecureUnarchiveFromData" or a subclass of NSSecureUnarchiveFromDataTransformer instead.

I'm creating an NSPersistentContainer at launch using the code below:

private let container: NSPersistentContainer = {
    let container = NSPersistentContainer(name: "MyApp", managedObjectModel: MyAppModelVersion.current.managedObjectModel())
    let storeDescription = NSPersistentStoreDescription(url: getStoreURLWithUserName())
    storeDescription.shouldMigrateStoreAutomatically = true
    storeDescription.shouldInferMappingModelAutomatically = true
    container.persistentStoreDescriptions = [storeDescription]
    return container
}()

Error occurs right after this line is executed:

let container = NSPersistentContainer(name: "MyApp", managedObjectModel: MyAppModelVersion.current.managedObjectModel())

I also have a property called 'Colorin aGroup` entity that's transformable:

@NSManaged public var color: UIColor?
@NSManaged public var hexColorValue: String?

Below is how set the property:

public var hexColor: String? {
    get {
        return self.hexColorValue
    }
    set {
        self.hexColorValue = newValue
        if let str = newValue {
            self.color = UIColor(hex: str)
        }
    }
}

This is what the property looks like in Core Data:

I am not sure how to recover from this crash. This was working fine with Xcode 10

Answer 1

Setting Transformer property to NSSecureUnarchiveFromDataTransformer solved the warning in my case. For this select the attribute & set its transformer type to NSSecureUnarchiveFromDataTransformer & run again by pressing commond+R.

Thanks, Ratneshwar