NSPersistentCloudKitContainer bugs - doesn't sync objects changed offline - ios

Question

I'm testing my implementation of CoreData + CloudKit Sync, using NSPersistentCloudKitContainer and it seems to work fine some of the time. I fixed the problem with users switching iCloud on/off in the settings as recommended by Apple, but the problem I now have is that when I'm testing my app offline, when I'm back online with an internet connection, there's no syncing. I've got some code which does correctly trigger and detect the presence of an internet connection or not.. but still it doesn't seem that setting the container options to nil and then back to the cloudkit container gets it to sync. Here's my code so far:
lazy var persistentContainer: NSPersistentContainer = {
/*
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 : NSPersistentContainer?
container = NSPersistentCloudKitContainer(name: "Model")
let description = NSPersistentStoreDescription(url: applicationDocumentsDirectory()!.appendingPathComponent("Model.sqlite"))
description.setOption(true as NSNumber,forKey: NSPersistentHistoryTrackingKey)
//Check if user is first logged onto iCloud enabled/not - if not then set cloudkitcontainer options to nil to disable sync and use the local DB on device
// This was from an accepted answer here: https://forums.developer.apple.com/thread/118924
//NB This works and the code here is triggered because a switch on/off icloud in settings kills the app and makes it restart, so this code is triggered.
if FileManager.default.ubiquityIdentityToken != nil { //logged onto iCloud*/
description.cloudKitContainerOptions = NSPersistentCloudKitContainerOptions(containerIdentifier: "iCloud.com.my.container")
} else {
description.cloudKitContainerOptions = nil;
}
//However, turning a device to airplane mode on/off won't kill the app to trigger the above code, so have to put that check in with checking when the device is on or offline:
monitor.pathUpdateHandler = { path in
if path.status == .satisfied {
description.cloudKitContainerOptions = NSPersistentCloudKitContainerOptions(containerIdentifier: "iCloud.com.my.container")
} else {
description.cloudKitContainerOptions = nil
}
}
//ensure migration------
description.shouldInferMappingModelAutomatically = true
description.shouldMigrateStoreAutomatically = true
//----------------------
container!.persistentStoreDescriptions = [description]
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)")
}
})
container!.viewContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy
container!.viewContext.automaticallyMergesChangesFromParent = true
return container!
}()
Edit
I just tried this from device to device and it seems to work if one device is put into offline mode momentarily without the monitor instance activated (commented that bit of the code out to test). However if the device is put into airplane mode for a prolonged period of time it seems that CloudKit updates aren't sent and it's synced from the other device rather than the latest change from the device I'm on...