Swift 6 - Sending

gistfile1.txt

import SwiftUI

// @MainActor // This would work, as the type now is isolated and the await does not cause a boundary change.
class SomethingNonSendable { // : Sendable { //, would work, because the type can now cross boundaries.
    
    let someActor: SomeActor = SomeActor()
    
//    nonisolated(nonsending) // This will make the await to be executed on the context -> MainActor
//    Upcoming feature flag Nonisolated​Nonsending​By​Default will make this the default behavior.
    func get() async -> Bool {
        
        // It does not matter where the context runs. The await dispatches to the actor.
        await someActor.get()
    }
    
}

actor SomeActor {

    func get() async -> Bool { true }
    
}

struct ContentView: View {
    
    let somethingNonSendable = SomethingNonSendable()
    
    @State private var value: Bool = false
    
    var body: some View {
        Text("Hello, world!")
            .onAppear {
                
                Task { // @MainActor in // Does not do anything, already is on MainActor. It is not important where the task runs, suspension happens at await.
                    
                    // let somethingNonSendable = SomethingNonSendable()
                    // This only makes the warning go away, because the Compiler can check, that it is not used otherwise and therefor has no race conditions.
                    
                    // Warning: Sending 'self.somethingNonSendable' risks causing data races
                    value = await somethingNonSendable.get() // The await is the actual suspension point, leaving MainActor, unless the func is nonisolated(nonsending).
                    
                }
                
            }
    }
}