Error "Trailing closure passed to parameter of type 'NSManagedObjectContext' that does not accept a closure" in Swift

Question

I try to add a live activity to my app, in Swift. But when I try to run the app, the error message "Trailing closure passed to parameter of type 'NSManagedObjectContext' that does not accept a closure" appear. My app uses Core Data to save the data of my app.

class HabitManager: ObservableObject {
    private var activity: Activity<HabitsWidgetAttributes>? = nil

    func startHabit(name: String, symbol: String, currentTask: String) {
        let attributes = HabitsWidgetAttributes(name: name, symbol: symbol)
        let state = HabitsWidgetAttributes.ContentState(currentTask: currentTask)
    
        activity = try? Activity<HabitsWidgetAttributes>.request(attributes: attributes, contentState: state)
    }

    func updateActivity(nextTask: String) {
        let state = HabitsWidgetAttributes.ContentState(currentTask: nextTask)
    
        Task { // Line where the error is generated
            await activity?.update(using: state)
        }
    }

    func stopActivity() {
        let state = HabitsWidgetAttributes.ContentState(currentTask: "Finished")
    
        Task { // Line where the error is generated
            await activity?.end(using: state, dismissalPolicy: .immediate)
        }
    }
}

What line generates the error? – Joakim Danielson Jan 08 '23 at 14:38 — Joakim Danielson, Jan 08 '23 at 14:38
At the two lines where there is a Task – Julien01 Jan 08 '23 at 15:29 — Julien01, Jan 08 '23 at 15:29
Did you create a CoreData Entity named "Task"? – EmilioPelaez Jan 08 '23 at 15:38 — EmilioPelaez, Jan 08 '23 at 15:38
Yes, it was the cause of the problem. – Julien01 Jan 08 '23 at 18:17 — Julien01, Jan 08 '23 at 18:17

score 5 · Accepted Answer · answered Jan 08 '23 at 15:50

If you create a CoreData entity called Task, then the compiler will try to use that instead of the Swift Task struct.

You can either rename your CoreData entity to something else (which I'd recommend), or you can call an async task by prefixing it with the module, in this case it would look like this:

Swift.Task {
  // do stuff
}

Since you'd have to do that everywhere, I would strongly recommend renaming your entity instead.

Error "Trailing closure passed to parameter of type 'NSManagedObjectContext' that does not accept a closure" in Swift

1 Answers1