In the summer, Apple published an informative sample app on sharing objects between iCloud users using Core Data, CloudKit and UICloudSharingController in SwiftUI: https://developer.apple.com/documentation/coredata/sharing_core_data_objects_between_icloud_users
However, Apple also announced the new Collaboration features for Messages in iOS16.
Now, it seems Collaboration is incompatible with UICloudSharingController and the sharing sheet it invokes, on iOS16.
MRE: See the Apple sample app linked above.
Reproduction:
- Create new share,
- Manage share with UICloudSharingController,
- Share With More People,
- Share using Messages (may succeed first time but fails on subsequent attempts on iOS16. Works great on iOS15).
Expectation: We can use UICloudSharingController to add new participants, using Messages, Mail or other platforms. The link will display correctly on all devices.
Reality: On iOS16+, attempting to share via Messages engages the "Collaboration" framework and leads to an alert: "An Error Occurred. Unable to start collaboration" (see Image 1). Triggering this error breaks ANY further shares - the link now cannot be created for Mail and other platforms either (see Image 2). Furthermore, if the first attempt succeeds, the link does not appear correctly on the receiving device (see Image 3). The link appears correctly when sent from a device running iOS15.
Question: How can this be resolved, so that we can share CloudKit records between users using Messages in iOS16+?
Images: https://imgur.com/a/o1fdABT
As of iOS 16.0.3, this issue appears to have gone away when using the Apple sample app. I am still using the same downloaded code, so a fix was possibly made by Apple on CloudKit side of things.
After investigating, I still encountered the issue when invoking UICloudSharingController using UIViewControllerRepresentable (like in the RayW sample code).
The issue does not appear (anymore) when invoking UICloudSharingController using UIViewController (like in the Apple sample code).
