Crashing: URLImage in tvOS NavigationLink

[NoahKamara]

Summary and/or background Whenever I try to use URLImage inside a NavigationLink in tvOS I get the following errors. (as soon as I focus the navigationLink)

It seems to be the same issue @abbasmousavi had but it wasn't addressed. Attempted to read an unowned reference but the object was already deallocated I am using 2.0.0alpha.1

Originally posted by @abbasmousavi in https://github.com/dmytro-anokhin/url-image/issues/84#issuecomment-706790028

OS and what device you are using

• OS: tvOS
• Apple TV Simulator

Version of URLImage library I've tested it with 2.1.1 and 2.0.0

• [x] The bug is reproducible in the latest version.

What you expected would happen The navigationLink element should go into focussed mode

What actually happens The App Crashes.

Fatal error: Attempted to read an unowned reference but the object was already deallocated2020-10-28 23:11:54.597926+0100 ABJC (ATV)[34705:1554277] Fatal error: Attempted to read an unowned reference but the object was already deallocated
Fatal error: Attempted to read an unowned reference but the object was already deallocated

It seems to happen in the cancel method (RemoteImage.swift, line 97), specifically on line 107 loadingState = .initial

Sample code The following code crashes almost immediately

struct TestView: View {
    func url() -> URL {
        let size = Int.random(in: 100...200)
        return URL(string: "https://picsum.photos/\(size)/\(size)")!
    }

    var body: some View {
        NavigationView {
            ScrollView([.horizontal]) {
                LazyHStack {
                    ForEach(1..<100, id:\.self) { i in
                        NavigationLink(destination: Text("")) {
                            URLImage(url: self.url()) {
                                image in
                                image
                                    .resizable()
                                    .clipShape(Circle())
                                    .frame(width: 300, height: 300)
                                    .clipped()
                            }
                        }.buttonStyle(PlainButtonStyle())
                    }
                }
            }
        }
    }
}

When I tweak the ForEach to get less values (20 worked for me) it doesn't immediately crash but only after I scroll through the items a little

Test data I used this site which let's you specify sizes to retrieve random images of that size 'https://picsum.photos/{width}/{height})'

Additional information: I've tried to narrow down the reason for the crash by making test views and changing them. I only got an error when the URLImage was inside a NavigationLink, that was itself inside a LazyStack.

[dmytro-anokhin]

Hey, thank you for proper bug report.

The crash is reproducible and I'm looking into it. This happens when object wrapped in @ObservedObject changes in onDisappear. I use it to cancel pending downloads. But the crash happens when onDisappear is triggered from dealloc of hosting UIView. I'm not sure if there is a guide not to publish changes in onDisappear.

For now, please comment out the line you mention (RemoteImage.swift - 107, loadingState = .initial). This will prevent publishing changes. I'm gonna do a bit more testing to see if there are any side effects, but this will probably be a workaround for the crash. You can point to version_2_1_2 branch.

[NoahKamara]

Hey, thanks for the quick reply. Keep up the great work I use this Package all the time :D

[dmytro-anokhin]

Hey, thanks, glad to hear this. The fix is in 2.1.2. I tested and it works. I'm closing this issue, feel free to reopen if you still can reproduce it. Cheers.