CloudKit NSPersistentCloudKitContainer push notifications not working

Question

I'm struggling to solve the following problem. Notwithstanding an in-depth search I did not succeed yet.

My development environment is Xcode 12.0 beta under macOS Big Sur Beta (however, the problem appears identical on Xcode 11.5 under Catalina). My app under development is multi-platform, both macOS 10.16 and iOS 13.5 target. The app is configured for CoreData with NSPersistentCloudKitContainer.

While registerForRemoteNotifications() succeeds without any problem in iOS target, and didRegisterForRemoteNotificationsWithDeviceToken is properly called, nothing happens in macOS target: neither didRegisterForRemoteNotificationsWithDeviceToken nor didFailToRegisterForRemoteNotificationsWithError are fired. Obviously CloudKit and PushNotification entitlement are properly configured on both macOs and iOS targets. Querying isRegisteredForRemoteNotifications returns true on macOS as well ...

The persistentContainer definition code is the same on both macOS and iOS (N.B. fully default, and the automaticallyMergesChangesFromParent is properly set)

var persistentContainer: NSPersistentCloudKitContainer = {
    let container = NSPersistentCloudKitContainer(name: "MyFinance")
    
    guard let description = container.persistentStoreDescriptions.first else {
        os_log("Failed to retrieve a persistent store description. Aborting application.", log: log, type: .error)
        fatalError("###\(#function): Failed to retrieve a persistent store description.")
    }
    description.setOption(true as NSNumber, forKey: NSPersistentHistoryTrackingKey)
    description.setOption(true as NSNumber, forKey: NSPersistentStoreRemoteChangeNotificationPostOptionKey)
    
    container.loadPersistentStores(completionHandler: { (storeDescription, error) in
        if let error = error {
            guard let error = error as NSError? else { return }
            os_log("Failed to load persistent store. Aborting application.", log: log, type: .error)
            fatalError("###\(#function): Failed to load persistent stores:\(error)")
        }
    })
    container.viewContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy
    container.viewContext.transactionAuthor = "xxx"
    
    do {
        try container.viewContext.setQueryGenerationFrom(.current)
    } catch {
        os_log("Failed to pin viewContext to the current generation. Aborting application.", log: log, type: .error)
        fatalError("###\(#function): Failed to pin viewContext to the current generation:\(error)")
    }
    container.viewContext.automaticallyMergesChangesFromParent = true
    
    return container
}()

The final result is that, while CoreData sync with push notifications is properly handled in the direction macOS -> iOS, nothing happens in the opposite direction (because push notifications on macOS are not fired): from iOS to macOS, CoreData are realigned at app boot only.

Anybody can please orient myself in the right direction? I'm banging my head on the wall from two days, without any sensible result...

P.S. there is another "symptom" when running the macOS target: any time an API call is fired in the app, and despite the call succeeds, the following message appears in the Xcode debug console:

nw_resolver_start_query_timer_block_invoke [Cxx] Query fired: did not receive all answers in time for xxx (the API url)

It does not happen for the iOS target. I am not able to find a decent explanation for that. I do not really know if this is somehow related to the push notification problem. No joy in searching the public domain about it.

Answer 1

I am not getting any callback from notifications on SwiftUI enabled app multiplatform on macOS.

Calling app.registerForRemoteNotifications() does nothing on macOS big sur, neighter I am getting

UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .sound, .badge,]) { [unowned self] (granted, error) in
            
}

Permission is not showing

IT seems to me it could be a bug.