Migrating Data to App Groups Disables iCloud Syncing - swift

Question

I am adding a Today Extension to my existing app. I have added the an App Group and used this post to successfully migrate my Core Data's data to the App Group's store. My app uses both a NSPersistentCloudKitContainer (when iCloud is toggled on) and a NSPersistentContainer (iCloud toggled off). While the data in both containers migrate successfully, I am no longer able to sync between my devices when using NSPersistentCloudKitContainer. In the console I get these two errors:
CoreData: error: CoreData+CloudKit: -[NSCloudKitMirroringDelegate _performSetupRequest:]_block_invoke(837): : Failed to set up CloudKit integration for store: (URL: file://path/name.sqlite)
Error Domain=NSCocoaErrorDomain Code=134060 "A Core Data error occurred." UserInfo={NSLocalizedFailureReason=The mirroring delegate could not initialize because it's store was removed from the coordinator.}
The path from the first error message is the path of the oldURL before switching to App Groups. So I believe I just need to tell iCloud to not try to integrate CloudKit at that store location and use the App Group's store location.
But I can not figure out how to do this. Can anyone help?
Core Data code:
class CoreDataManager {
static let sharedManager = CoreDataManager()
private init() {}
lazy var persistentContainer: NSPersistentContainer = {
var useCloudSync = UserDefaults.standard.bool(forKey: "useCloudSync")
//Get the correct container
let containerToUse: NSPersistentContainer?
if useCloudSync {
containerToUse = NSPersistentCloudKitContainer(name: "App")
} else {
containerToUse = NSPersistentContainer(name: "App")
}
guard let container = containerToUse else {
fatalError("Couldn't get a container")
}
//Set the storeDescription
let storeURL = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: "group.App")!.appendingPathComponent("\(container.name).sqlite")
var defaultURL: URL?
if let storeDescription = container.persistentStoreDescriptions.first, let url = storeDescription.url {
defaultURL = FileManager.default.fileExists(atPath: url.path) ? url : nil
}
if defaultURL == nil {
container.persistentStoreDescriptions = [NSPersistentStoreDescription(url: storeURL)]
}
let description = container.persistentStoreDescriptions.first else {
fatalError("Hey Listen! ###\(#function): Failed to retrieve a persistent store description.")
}
description.setOption(true as NSNumber, forKey: NSPersistentStoreRemoteChangeNotificationPostOptionKey)
if !useCloudSync {
description.setOption(true as NSNumber, forKey: NSPersistentHistoryTrackingKey)
}
container.loadPersistentStores(completionHandler: { (storeDescription, error) in
//migrate from old url to use app groups
if let url = defaultURL, url.absoluteString != storeURL.absoluteString {
let coordinator = container.persistentStoreCoordinator
if let oldStore = coordinator.persistentStore(for: url) {
do {
try coordinator.migratePersistentStore(oldStore, to: storeURL, options: nil, withType: NSSQLiteStoreType)
} catch {
print("Hey Listen! Error migrating persistent store")
print(error.localizedDescription)
}
// delete old store
let fileCoordinator = NSFileCoordinator(filePresenter: nil)
fileCoordinator.coordinate(writingItemAt: url, options: .forDeleting, error: nil, byAccessor: { url in
do {
try FileManager.default.removeItem(at: url)
} catch {
print("Hey Listen! Error deleting old persistent store")
print(error.localizedDescription)
}
})
}
}
}
return container
}
}

Answer 1

If you are still facing the same problem, you should add the following line for the storeDescription
storeDescription.cloudKitContainerOptions = NSPersistentCloudKitContainerOptions(containerIdentifier: "iCloud.com.yourapp.identifier")
Source: https://developer.apple.com/videos/play/wwdc2019/202/
Following is my CoreDataStack:
import CoreData
class CoreDataStack {
// MARK: - Core Data stack
static var persistentContainer: NSPersistentCloudKitContainer = {
/*
The persistent container for the application. This implementation
creates and returns a container, having loaded the store for the
application to it. This property is optional since there are legitimate
error conditions that could cause the creation of the store to fail.
*/
let container = NSPersistentCloudKitContainer(name: "data")
let storeURL = URL.storeURL(for: "group.com.myapp", databaseName: "data")
let storeDescription = NSPersistentStoreDescription(url: storeURL)
storeDescription.cloudKitContainerOptions = NSPersistentCloudKitContainerOptions(containerIdentifier: "iCloud.com.myapp")
container.persistentStoreDescriptions = [storeDescription]
container.loadPersistentStores(completionHandler: { (storeDescription, error) in
if let error = error as NSError? {
// Replace this implementation with code to handle the error appropriately.
// fatalError() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
/*
Typical reasons for an error here include:
* The parent directory does not exist, cannot be created, or disallows writing.
* The persistent store is not accessible, due to permissions or data protection when the device is locked.
* The device is out of space.
* The store could not be migrated to the current model version.
Check the error message to determine what the actual problem was.
*/
fatalError("Unresolved error \(error), \(error.userInfo)")
}
})
return container
}()
// MARK: - Core Data Saving support
static func saveContext () {
let context = persistentContainer.viewContext
if context.hasChanges {
do {
try context.save()
} catch {
// Replace this implementation with code to handle the error appropriately.
// fatalError() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
let nserror = error as NSError
fatalError("Unresolved error \(nserror), \(nserror.userInfo)")
}
}
}
}
public extension URL {
/// Returns a URL for the given app group and database pointing to the sqlite database.
static func storeURL(for appGroup: String, databaseName: String) -> URL {
guard let fileContainer = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: appGroup) else {
fatalError("Shared file container could not be created.")
}
return fileContainer.appendingPathComponent("\(databaseName).sqlite")
}
}