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")
}
}
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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,
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,
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.
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)")
}
}
}
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,
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))
	}
}