iOS 15 only : Alert leaves behind invisible window that steals all user interaction

[paddlefish]

Please provide all the information requested. Issues that do not follow this format are likely to stall.

Description

Something changed about how UIWindow and the root view controller interact. the _alertWindow created in RCTAlertController is no longer removed from the screen when nil'd in - (void) hide. I suspect that somewhere a retain cycle was introduced by the iOS 15 runtime.

React Native version:

System:
    OS: macOS 11.6
    CPU: (8) x64 Intel(R) Core(TM) i7-4980HQ CPU @ 2.80GHz
    Memory: 46.57 MB / 16.00 GB
    Shell: 5.8 - /bin/zsh
  Binaries:
    Node: 14.17.5 - ~/.nvm/versions/node/v14.17.5/bin/node
    Yarn: 1.22.11 - ~/.nvm/versions/node/v14.17.5/bin/yarn
    npm: 7.23.0 - ~/.nvm/versions/node/v14.17.5/bin/npm
    Watchman: 2021.06.07.00 - /usr/local/bin/watchman
  Managers:
    CocoaPods: 1.11.2 - /Users/arahn/.rvm/gems/ruby-2.6.3/bin/pod
  SDKs:
    iOS SDK:
      Platforms: iOS 15.0, DriverKit 20.4, macOS 11.3, tvOS 15.0, watchOS 8.0
    Android SDK: Not Found
  IDEs:
    Android Studio: 4.2 AI-202.7660.26.42.7351085
    Xcode: 13.0/13A233 - /usr/bin/xcodebuild
  Languages:
    Java: 1.8.0_65 - /usr/bin/javac
  npmPackages:
    @react-native-community/cli: Not Found
    react: 17.0.2 => 17.0.2 
    react-native: 0.65.1 => 0.65.1 
    react-native-macos: Not Found
  npmGlobalPackages:
    *react-native*: Not Found

Steps To Reproduce

1. Call Alert.alert, e.g.

    InteractionManager.runAfterInteractions(() => {
      Alert.alert('Delete this post?', 'Are you sure you want to permanently delete this?', [
        {
          text: 'Cancel',
          style: 'cancel',
        },
        {
          onPress: () => someFunction(),
          text: 'Delete',
          style: 'destructive',
        },
      ])
    })

2. Run code and dismiss alert.
3. Use XCode to pause app execution an look at UIView hierarchy.

Expected Results

You can interact with the app still

There are no extra windows still on the screen after alert is dismissed

Actual Results

all user interaction is blocked. There is a Window and a UIViewController still on the screen.

[asafkorem]

I am able to reproduce this also. With both iOS 15 and iOS 14.5.

[asafkorem]

That's a serious issue here, it also breaks automation tests when using Detox (and a real bug generally). 🔴 🔴 🔴
Note that the overlay seems to disappear after the first touch gesture attempt (only the first gesture is blocked).

[MoOx]

I confirm this is a serious issue very annoying for user. I am facing it using RN 0.64.2.

[asafkorem]

This issue was resolved in RN v.67.1.
Thanks @paddlefish

[MoOx]

Yep, same finding, RN 0.67 fixed this

[paddlefish]

Thanks to all involved. That was an interesting journey.