watchOS 10: CloudKit CoreData Sync (NSPersistentCloudKitContainer) Requires Watch on Charger

Please file a Feedback (https://developer.apple.com/bug-reporting/) and link it here, including a sysdiagnose covering your reproduction with CloudKit logging enabled (https://developer.apple.com/bug-reporting/profiles-and-logs/?name=cloudkit). That will hopefully allow us to understand the root cause of the symptoms you see. Thank you!

Thanks. I filed a Feedback earlier (FB13183124) and submitted a sysdiagnose with the CloudKit profile installed.

What are your logs showing? I'm having issues as well on both iOS 17 and watchOS 10. The most interesting part is this:

("CoreData: CloudKit Setup"), was created over 30 seconds ago. In applications running in the background, this creates a risk of termination. Remember to call UIApplication.endBackgroundTask(_:) for your task in a timely manner to avoid this.

Also, do you see your app contacting iCloud servers in app privacy report?

I have been able to fix iCloud CoreData sync by migrating my watch app from an extension to a single app using the upgrade process offered by Xcode. While CoreData CloudKit syncing is now working correctly, the migration has created a separate issue with CoreLocation as highlighted in another forum discussion:

https://developer.apple.com/forums/thread/736785

Thanks for the update. Can you please indicate where in Xcode to find the process you mentioned (to upgrade a watch app from an extension to a single app)?

I believe you'll find this option in the issue navigator, but I cannot remember if that's the spot. Assuming your project fits what Xcode is looking for, Xcode should provide you with the option to merge your watchOS App Target and Extension Target targets into a single target.

Select the project file in Xcode 15, select the [Editor] menu, select [Validate Settings], then a check box will appear prompting to migrate to a single app. This method improved the issue, but I would like an official statement from Apple as to whether the old extension format apps are no longer supported.

Thanks for the details, I see the option there. I have the same concern about whether the old extension format apps re no longer supported. Apple documentation doesn't appear to have been updated for Xcode 15 in regards to creating a phone app with a companion watch app. The steps involved in are quite different and, from what I can see, such apps are now created with a single watch app target.

And forgive me if this question is slightly off topic, but has anyone else also seen their watch apps being inexplicably terminated?

I finally got to the point where I used Xcodes's process to upgrade my app from an extension to a single app. Once I did, the app crashes during the launch process with a signal SIGABRT error pointing to : class ApplicationDelegate: NSObject, WKApplicationFelegate (I renamed the class from ExtensionDelegate) with no indication of it having been a particular line of code that led to it. Just a general question, were there any other obvious changes that needed to be made for this to work?

For anyone else running into this issue, in my case at least (developed in Swift and using storyboard), after using the Xcode tool to migrate to a single app, I needed to go into the storyboard and change the Module for every interface controller and row controller I had created. These still specified the watch app extension rather than the watch app.