“SwiftData inheritance relationship”

Could anyone from Apple weigh in on this? this is a real and easily reproducible issue. on active scenePhase, if CloudKit, specially SwiftData, is enabled… there is a noticeable hang first few seconds. I am assuming it has to do with the @Query sync with remote.

So, the first thing to understand here is that the IOKitPersonalities is called that because it IS in fact a fully valid IOKitPersonalities dictionary. That is, what the system actually uses that dictionary for is: Perform a standard IOKit match and load cycle in the kernel. The final driver in the kernel then uses the DEXT-specific data to launch and run your DEXT process outside the kernel. So, working through the critical keys in that dictionary: IOProviderClass-> This is the in-kernel class that your driver loads on top of. In your case, that would be IOSCSIPeripheralDeviceNub or one of its variants. IOClass-> This is the in-kernel class that your driver loads on top of. This is where things can become a bit confused, as some families work by: Routing all activity through the provider reference so that the DEXT-specific class does not matter (PCIDriverKit). Having the DEXT subclass a specific subclass which corresponds to a specific kernel driver (SCSIPeripheralsDriverKit). This distinction is descr

Nice to know that the original issue goes away in the latest Beta. Regarding the crash triggered by the access to Item.children, if you can provide a runnable code snippet to demo the issue, I'll take another look. You have mentioned a few classes with inheritance, and so I think it is probably worth mentioning that over-using inheritance may impact your app's performance negatively. Concretely, with today's default store (DefaultStore), all the types in an inheritance hierarchy are persisted with one single table in SQLite. If your inheritance hierarchy has many classes, the table (columns and data) can be quite big, which can slow down the performance of fetching and inserting data. That being said, when adopting SwiftData inheritance, you might examine if that is a right use case. This WWDC25 session(starting from around 4:25) covers this topic a bit. You can take a look, if haven't yet. Best, —— Ziqiao Chen  Worldwide Developer Relations.

I’m not sure of your relationship to niggeulimann, but I responded to their copy of this question over on this thread. Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = eskimo + 1 + @ + apple.com

Hi Ziqiao, I've tried with iOS 26 Beta 7 and since Beta 8 (landed tonight) on device (because my Xcode is stuck on iOS Beta 6, don't know why) and the problem is solved. I can now query CollectionItem with predicate that contains inherited properties. Now I have only got problems with accesses to the children property in List. When i got the following hierarchy and the SwiftUI view List access to the Item.children property I got another kind of crash. Category: Work (parent: none) Category: Tech (parent: Work) Thread 1: Fatal error: Never access a full future backing data - PersistentIdentifier(id: SwiftData.PersistentIdentifier.ID(backing: SwiftData.PersistentIdentifier.PersistentIdentifierBacking.managedObjectID(0x9872c0007ba42159 ))) with Optional(7639D151-5D48-46AC-AB2A-7F0F50919AC5) But I guess it's a different kind of problem now.

it would be helpful to see a small test project that has the relationship between your navigation toolbar and the content view set up the same way as your real app and see if you get the same results. If so, please provide a link to that test project. — Ed Ford,  DTS Engineer

There are some subtle things that determine if a change on a SwiftData model is observable, as discussed in this WWDC25 session (starting from around 14:00.) Your code snippet doesn't show where the folder in FolderView is from and how you add a new item. If you can share a runnable code snippet that demonstrates the issue, I'd be able to figure out why folder doesn't trigger an update. Best, —— Ziqiao Chen  Worldwide Developer Relations.

The use of the inheritance, as shown in the above code snippet, looks fine to me, and I don't really see a crash by running the code on my iOS 26 Beta 7 simulator and device. So did you try with Beta 7, the latest Beta as of today, yet? Best, —— Ziqiao Chen  Worldwide Developer Relations.

Answering my own question. Found this blog, searching for answers https://blog.jacobstechtavern.com/p/swiftdata-outside-swiftui Thanks Jacob. The answer is simple, but maybe someone can explain. modelContext = container.mainContext works if it's modelContext = ModelContext(container) Done!