Xcode 12 GM runs into infinite loop

Question

I am developing an iOS app and it works well on Xcode 11.7, but when I run the same code in Xcode 12 and when I enter a UIPageViewController, the app runs into an infinite loop and the cpu usage shows 99%. Here is a screenshot I made after pause the app in debugger.

It shows Application violated contract by causing UIApplicationMain() to return. This incident will be reported.

I'm using SwiftUI and my code also runs ok before xCode 12. Now is just throwing errors everywhere in the UI. Is there someone knows what's going on? — Philip Borbon, Sep 17 '20 at 06:52
I'm having the same problem here..all good before Xcode12..did you find a solution? — Matteo Gobbi, Oct 06 '20 at 04:58

score 0 · Answer 1 · answered Sep 17 '20 at 08:53

I have encountered similar crashes in Xcode 12. I resolved them by removing a custom loading spinner from my view, which seems to have created these problems. The loading spinner looks like this (maybe you are using similar animation code in your app?):

struct Spinner: View {
    
    @State private var isSpinning = false
    
    var body: some View {
        Circle()
            .trim(from: 1/5, to: 1)
            .stroke(style: StrokeStyle(lineWidth: 2, lineCap: .round, lineJoin: .round))
            .rotationEffect(.degrees(isSpinning ? 360 : 0))
            .animation(Animation.linear(duration: 1).repeatForever(autoreverses: false))
            .onAppear() {
                self.isSpinning = true
            }
    }
}

I am using UIKit in my app, it seems that Xcode has some bugs on UI — Collin Zhang, Sep 18 '20 at 14:07

score 0 · Answer 2 · answered Nov 17 '20 at 23:51

In my case I was instanciating a drawer controller from AppDelegate (MMDrawerController)

Any resizing of height of a view past its scrollview or putting too long text in UILabel created the issue 100% CPU, memory upping...

Issue was I was pushing a view controller instead of a nav. which usually is fine, but seems OS does not like it much

score 0 · Answer 3 · answered Nov 18 '20 at 05:18

0

In mine case sometimes (??) happens on app simulator startup. Stopping and replay solves and don't have any alert from test teams on real devices.

answered Nov 18 '20 at 05:18

Massimo Pavanel

754
8
7

score 0 · Answer 4 · answered Sep 16 '21 at 08:53

0

This happened to me when I forgot to add a dot before a view modifier. So check your dots, I guess.

https://developer.apple.com/forums/thread/663970

answered Sep 16 '21 at 08:53

kkopec

1
1

Xcode 12 GM runs into infinite loop

4 Answers4