Timac / FB9687147-swiftui-animation-deinit-thread

This sample Xcode project demonstrates a SwiftUI issue (FB9687147)

Description

This simple Xcode project demonstrates an issue with SwiftUI where a View animation triggers deinit in a thread. This issue has been reported as FB9687147 to Apple.

Steps to Reproduce

• Download the sample Xcode project DeinitInThread
• Open this project in Xcode 13.0
• Compile and run this project on iOS 15.0 on a device or simulator
• Tap on the button Switch to Sample View
• Tap on the button Switch to Content View

Result: In the Xcode console you will see a warning that the deinit is called in a thread

"**** DEINIT running in some thread <NSThread: 0x600001c899c0>{number = 8, name = (null)}"

Reproducibility

• This issue can be reproduced with Xcode 13.0 when running on iOS 15.0 on a device or simulator.
• This issue was not yet tested on iOS 15.1 beta.

Details

• The Xcode project contains 2 SwiftUI views.
• A button lets you switch from one view to the second view with an animation.
• If the view has a viewModel, the deinit for the viewModel is called in a thread rather than in the main thread:

struct ContentView: View {
	@EnvironmentObject var appState: AppState

	var body: some View {
		VStack(spacing: 0) {
			switch appState.contentType {
				case .homeScreen:
					Button {
						appState.contentType = .contact
					} label: {
						Text("Switch to Sample View")
					}
				default:
					SampleView()
			}

		}.animation(.default, value: appState.contentType)
	}
}