Hello,I recently see sometimes crashing errors with statements like "precondition failure: attribute failed to set an initial value: 103" logged to the console. The numbers at the end vary. Has anybody found a good way (or any way besides blindly trying to change things ;-) to track down those errors?Cheers, Michael

Hi, is it possible to have access to NSApplicationDelegate methods like application(_ sender: NSApplication, openFiles filenames: [String]) when using the Swift UI App Life Cycle? With "access" I mean equivalent functionality. I know there is support for a document based app using the Swift UI App Life Cycle, which would seem to resolve the issue for that particular openFiles delegate method, but for various reasons I can't use the document based app life cycle. Thank you! Cheers, Michael

Hi, I have a strange case involving sheets, which I think it's a bug, but then again I might be missing something. Using the following code: import SwiftUI enum WhichSheet: String { 	case one, two, three, none } struct ContentView: View { 	@State private var _showSheet = false 	@State private var _whichSheet: WhichSheet = .none 		var body: some View { 			VStack(spacing: 8) { 					Button("One Sheet", action: { self._whichSheet = .one; self._showSheet = true}) 					Button("Two Sheet", action: { self._whichSheet = .two; self._showSheet = true}) 					Button("Three Sheet", action: { self._whichSheet = .three; self._showSheet = true}) 			} 				.sheet(isPresented: $_showSheet, content: { 				Text("whichSheet = \(_whichSheet.rawValue)") 			}) 		} } struct ContentView_Previews: PreviewProvider { 		static var previews: some View { 			ContentView() 		} } I would assume that, depending on which button is pressed, I would say a sheet with the text "whichSheet = one" or "whichSheet = two" etc. But no matter which button is pressed first the text on the sheet is always "whichSheet = none". Only if you choose a different button the second (or third, or ...) time the correct text is being displayed. Bug or am I missing something really obvious? (Test using an iOS 14 / 14.2 project with Xcode 12 / 12.2 beta) Cheers, Michael

Hi, I am wondering if anybody who is facing issues with @State not working properly in iOS 14 has received any update on that from Apple? Since having working @State properly is quite essential to have a working SwiftUI implementation I am a bit puzzled to not have gotten any update at all on the issue from Apples side. That's the issue I am encountering: https://developer.apple.com/forums/thread/660976 Here are a few other threads from the forum which at least seem to be related to this issue: https://developer.apple.com/forums/thread/652080 https://developer.apple.com/forums/thread/652258 https://developer.apple.com/forums/thread/661818 https://developer.apple.com/forums/thread/660927 https://developer.apple.com/forums/thread/661777 https://developer.apple.com/forums/thread/659660 https://developer.apple.com/forums/thread/661754

Hi, I have a very simple program (see below) with some Views in an HStack, which is within a ScrollView. This works fine on iOS, but on macOS nothing scrolls. Am I missing something? Shouldn't it just scroll? import SwiftUI struct ContentView: View { 	var body: some View { 		ScrollView(.horizontal, showsIndicators: true) { 			HStack { 				ItemView(n: 1) 				ItemView(n: 2) 				ItemView(n: 3) 				ItemView(n: 4) 				ItemView(n: 5) 			} 		} 		.frame(minWidth: 350, maxWidth: 800, minHeight: 250, maxHeight: 250, alignment: .center) 	} } struct ContentView_Previews: PreviewProvider { 	static var previews: some View { 		ContentView() 	} } struct ItemView: View { 	var n: Int 	 	var body: some View { 		Rectangle() 			.frame(width: 300, height: 200) 			.overlay(Text("\(n)").foregroundColor(.white)) 	} }

Hi, I want to have more than one MKAnnotation to be selected, but so far it seems that it is not possible, is that true? If yes are there any workarounds? MKMapView has the selectedAnnotations property, which is an Array and also set-able, but the documentation states: "Assigning a new array to this property selects only the first annotation in the array.". So I am wondering why this even is an Array and if there is in fact a way to have multiple annotations selected, that I am not aware of... Any help, hints highly appreciated :-). Cheers, Michael

Hi, the documentation for @State says: You should only access a state property from inside the view’s body, or from methods called by it. Therefore I am wondering of this is an incorrect (as aValue is set/accessed outside of a "view's body") usage of @State which, while it works now, might break in the future: @main struct SwiftUIArrayUpdateTestApp: App { 	@State private var aValue = 5 	var body: some Scene { 		WindowGroup { 			ContentView(value: $aValue) 		} 	} }

Hi, I am trying to develop a "ui control", which should react on, for example, the cursor keys when in focus. I could not find anything in the docs regarding keyboard and focus handling. Has anybody any hints on how to achieve this or where to get information on that topic? Thank you! Cheers, Michael

Hi, is there a way that an actor can have a @MainActor @Published annotated property which is then consumed by a SwiftUI View "as usual"? Currently this: @Published @MainActor public private(set) var state: State = .initial gives me the following error when trying to access it from with a SwiftUI View: "Actor-isolated property '$state' can only be referenced from inside the actor" I guess I understand where the error is coming from, but I wonder if there's a way to publish properties from actors and be able to make sure they are updated on the main thread by annotating them with @MainActor.

I am getting a strange crash (see call stack in attached screenshot). I am looking for ideas/hints how to track down what the issue is?

Hi, when using URL session nested in a few async/await calls I get a crash in swift_getObjectType (sometimes in processDefaultActor). Any ideas what could be causing this or hints how to debug/where to look? For a (contrived - because it was extracted from a larger project) example please see below (see "crashes here" comment for the last call before the crash). Thanks for any hints in advance! Cheers, Michael // Crash on: Xcode Version 13.0 beta (13A5155e), macOS 11.4 (20F71), on iPhone Simulator import CoreData import SwiftUI struct ContentView: View { @StateObject var dataCoordinator: DataCoordinator = .init() var body: some View { Button { print("GO") async { try await dataCoordinator.api.getSomething() } } label: { Label("Go", systemImage: "figure.walk") } .buttonStyle(.bordered) } } struct ContentView_Previews: PreviewProvider { static var previews: some View { ContentView().environment(\.managedObjectContext, PersistenceController.preview.container.viewContext) } } // MARK: - Test coding - class DataCoordinator: ObservableObject { let api: API = .init() func refreshSomething() async throws { try await api.getSomething() } } // MARK: - class API { var session: URLSession = .init(configuration: .ephemeral) func getSomething() async throws { let url = URL(string: "https://www.heise.de")! let request = URLRequest(url: url) let (data, response) = try await _failsafe(request: request) print("\(response)") } private func _failsafe(request: URLRequest) async throws -> (Data, URLResponse) { do { var (data, response) = try await session.data(for: request) let httpResponse = response as! HTTPURLResponse var recovered = false if httpResponse.allHeaderFields["dsfsfsdsfds"] == nil { let login = LoginAsync() await login.login(session: session) recovered = true } if recovered { let req2 = URLRequest(url: URL(string: "https://www.heise.de")!) print("right before crash") try await session.data(for: req2) // crashes here with EXC_BAD_ACCESS print("right after crash ;-)") } return (data, response) } catch { print("\(error)") throw error } } } // MARK: - actor LoginAsync { func login(session: URLSession) async { let url = URL(string: "https://www.google.com")! let request = URLRequest(url: url) do { let (data, response) = try await session.data(for: request) } catch { print("\(error)") } } }

Hi, since the Xcode 13 beta 5 I am seeing crashes in _os_semaphore_dispose.cold.* when running in the iOS simulator. This happens in different apps under various conditions, so I can pin it down to something specific. Is anybody else having similar issues? Stack of the crashing thread looks like this: Disassembly looks like this: Thanks for any feedback. Cheers, Michael

Hi, I want to import GPX files into my iOS App. It works fine in the simulator using: .fileImporter(isPresented: $showFileImporter, allowedContentTypes: [UTType(filenameExtension: "gpx")!, UTType(filenameExtension: "GPX")!], allowsMultipleSelection: true) But running the app on an actual device (iOS 15 Beta 6), I am not allowed to select any of the GPX files. The strange thing is, that if I am using "jpg" instead of "gpx" I can select "jpg" files just fine. So it seems, that it has to do something with the "GPX" type being 'custom'. Any idea/hint what I am missing? Thank you! Michael

Hi, I am using a child NSManagedContext trying to isolate changes to a NSManagedObject from changes done to the same object in the parent NSManagedObjectContext. This works fine for normal properties, but any changes to relationships performed on the object in the parent context will show up immediately in the child object as well. Is this the intended behavior? If yes is there a way to create an "isolated" version of an NSManagedObject? Thanks in advance for any hints! Cheers, Michael

Hi, having the concurrency checks (-Xfrontend -warn-concurrency -Xfrontend -enable-actor-data-race-checks-Xfrontend -warn-concurrency -Xfrontend -enable-actor-data-race-checks) enabled I always get this warning, when trying to access/use an actor in a SwiftUI .task: "Cannot use parameter 'self' with a non-sendable type 'ContentView' from concurrently-executed code". What would be a correct implementation? Here's a minimal code-sample which produces this warning: import SwiftUI struct ContentView: View { @State var someVar = 5 var a1 = A1() var body: some View { Text("Hello, world!") .padding() .task { await a1.doSomething() } } } public actor A1 { func doSomething() { print("Hello") } }