I’m exploring macOS development, comparing Mac Catalyst apps vs native AppKit/SwiftUI apps. What are the main limitations of Catalyst today? In what scenarios is a native AppKit or SwiftUI app unavoidable? Any insights are much appreciated — I’m trying to understand when Catalyst is sufficient and when going native is worth the extra effort.

Hi everyone, On macOS 26.4 beta (with Xcode 26.4 beta), I’m seeing the following console messages in a brand new SwiftData + CloudKit template project (no custom logic added, fresh CloudKit container): updateTaskRequest called for a pre-running task com.apple.coredata.cloudkit.activity.export.F9EE783D-7521-4EC2-B42C-9FD1F29BA5C4 updateTaskRequest called for an already running/updated task com.apple.coredata.cloudkit.activity.export.F9EE783D-7521-4EC2-B42C-9FD1F29BA5C4 Error updating background task request: Error Domain=BGSystemTaskSchedulerErrorDomain Code=8 "(null)" These messages appear: When CloudKit is enabled Occasionally on app launch Often when bringing the app back to the foreground (Cmd-Tab away and back) Even with zero additional SwiftData logic They do not appear when CloudKit is disabled. This behavior is reproducible on a completely new project with a fresh CloudKit container. Questions: What exactly do these messages indicate? Is BGSystemTaskScheduler Code=8 expected in this context? Are these safe to ignore? Is this a known change in logging behavior in macOS 26.4 beta? Additionally, in a larger project I’ve observed SwiftData crashes and initially suspected these logs might be related. However, since the issue reproduces in a fresh template project, I’m unsure whether this is simply verbose beta logging or something more serious. Any clarification would be appreciated. Filed as FB21993521.

Hi everyone, I’m trying to reproduce the layout Apple Music uses for playlists, where there is header content above the table (artwork, title, buttons), and when you scroll, everything scrolls together—the header and table rows move as a single scrollable region. Here’s an example of what I’m trying to achieve: I’m using SwiftUI’s Table view and I haven’t found a clean way to place custom content above the table while keeping everything inside the same scroll view. Is there currently a recommended way to achieve Apple Music–style scrollable header + table content using SwiftUI? Thanks!

With iOS 26 there has been a change in behavior with Pickers in the toolbar. The Picker looks expanded unlike other views such as a Button and Menu. See screenshots below. Is this the intended behavior or a bug? (I already submitted a feedback for this at FB19276474) What Picker looks like in the toolbar: What Button looks like in the toolbar:

Hi all, I’m trying to understand SwiftData’s runtime semantics around optional to-many relationships, especially in the context of CloudKit-backed models. I ran into behavior that surprised me, and I’d like to confirm whether this is intended design or a potential issue / undocumented behavior. Minimal example import SwiftUI import SwiftData @Model class Node { var children: [Node]? = nil var parent: Node? = nil init(children: [Node]? = nil, parent: Node? = nil) { self.children = children self.parent = parent print(self.children == nil) } } struct ContentView: View { var body: some View { Button("Create") { _ = Node(children: nil) } } } Observed behavior If @Model is not used, children == nil prints true as expected. If @Model is used, children == nil prints false. Inspecting the macro expansion, it appears SwiftData initializes relationship storage using backing data placeholders and normalizes to-many relationships into empty collections at runtime, even when declared as optional. CloudKit context From the SwiftData + CloudKit documentation: “The iCloud servers don’t guarantee atomic processing of relationship changes, so CloudKit requires all relationships to be optional.” Because of this, modeling relationships as optional is required when syncing with CloudKit, even for to-many relationships. This is why I’m hesitant to simply switch the model to a non-optional [Node] = [], even though that would match the observed runtime behavior. Questions Is it intentional that optional to-many relationships in SwiftData are never nil at runtime, and instead materialize as empty collections? If so, is Optional<[Model]> effectively treated as [Model] for runtime access, despite being required for CloudKit compatibility? Is the defaultValue: nil in the generated Schema.PropertyMetadata intended only for schema/migration purposes rather than representing a possible runtime state? Is there a recommended modeling pattern for CloudKit-backed SwiftData models where relationships must be optional, but runtime semantics behave as non-optional? I’m mainly looking to ensure I’m aligning with SwiftData’s intended design and not relying on behavior that could change or break with CloudKit sync. Thanks in advance for any clarification!

I'm building a SwiftUI app with SwiftData and want to centralize both query logic and related actions in a manager class. For example, let's say I have a reading app where I need to track the currently reading book across multiple views. What I want to achieve: @Observable class ReadingManager { let modelContext: ModelContext // Ideally, I'd love to do this: @Query(filter: #Predicate<Book> { $0.isCurrentlyReading }) var currentBooks: [Book] // ❌ But @Query doesn't work here var currentBook: Book? { currentBooks.first } func startReading(_ book: Book) { // Stop current book if any if let current = currentBook { current.isCurrentlyReading = false } book.isCurrentlyReading = true try? modelContext.save() } func stopReading() { currentBook?.isCurrentlyReading = false try? modelContext.save() } } // Then use it cleanly in any view: struct BookRow: View { @Environment(ReadingManager.self) var manager let book: Book var body: some View { Text(book.title) Button("Start Reading") { manager.startReading(book) } if manager.currentBook == book { Text("Currently Reading") } } } The problem is @Query only works in SwiftUI views. Without the manager, I'd need to duplicate the same query in every view just to call these common actions. Is there a recommended pattern for this? Or should I just accept query duplication across views as the intended SwiftUI/SwiftData approach?

Hi everyone, In the simple app below, I have a QueryView that has LazyVStack containing 100k TextField's that edit the item's content. The items are fetched with a @Query. On launch, the app will generate 100k items. Once created, when I press any of the TextField's , a severe hang happens, and every time I type a single character, it will cause another hang over and over again. I looked at it in Instruments and it shows that the main thread is busy during the duration of the hang (2.31 seconds) updating QueryView. From the cause and effect graph, the update is caused by @Observable QueryController <Item>.(Bool). Why does it take too long to recalculate the view, given that it's in a LazyVStack? (In other words, why is the hang duration directly proportional to the number of items?) How to fix the performance of this app? I thought adding LazyVStack was all I need to handle the large dataset, but maybe I need to add a custom pagination with .fetchLimit on top of that? (I understand that ModelActor would be an alternative to @Query because it will make the database operations happen outside of the main thread which will fix this problem, but with that I will lose the automatic fetching of @Query.) Thank you for the help! import SwiftData import SwiftUI @main struct QueryPerformanceApp: App { var body: some Scene { WindowGroup { ContentView() .modelContainer(for: [Item.self], inMemory: true) } } } @Model final class Item { var name: String init(name: String) { self.name = name } } struct ItemDetail: View { @Bindable var item: Item var body: some View { TextField("Name", text: $item.name) } } struct QueryView: View { @Query private var items: [Item] var body: some View { ScrollView { LazyVStack { ForEach(items) { item in VStack { ItemDetail(item: item) } } } } } } struct ContentView: View { let itemCount = 100_000 @Environment(\.modelContext) private var context @State private var isLoading = true var body: some View { Group { if isLoading { VStack(spacing: 16) { ProgressView() Text("Generating \(itemCount) items...") } } else { QueryView() } } .task { for i in 1...itemCount { context.insert(Item(name: "Item \(i)")) } try? context.save() isLoading = false } } }