`TypeError: Cannot read properties of null (reading 'unmount')` crash on Android when going from background to foreground

[dangrima90]

I found this issue whilst investigating this NativeScript issue: NativeScript/NativeScript#8126.

The issue happens after a navigation with clearHistory: true occurs and then the user proceeds to exiting the application via the back button. I noticed that this issue seemed to only happen on Android 11 or lower, testing with Android 12 did not result in the issue.

Showcase:

418283966-822d88c6-bc85-4626-8e90-1bdc16af4b06.mov

Code of the above showcase can be found here: https://github.com/dangrima90/android-navigation-issue.

From my investigation the issue seems to be coming from here: https://github.com/nativescript-vue/nativescript-vue/blob/main/src/plugins/navigation.ts#L85-L88

Locally I managed to workaround the issue by changing the code linked above,

From:

if (!isReloading) {
  view.unmount();
  view = null;
}

To:

if (!isReloading && view) {
  view.unmount();
  view = null;
}

I could apply the fix myself, however I'm not fully aware of what this part of the code is doing so I'm hesitant to assume that just checking whether view has a value handles all use cases.

[vallemar]

@dangrima90 I think this is related to this core PR

CC @CatchABus

[CatchABus]

@dangrima90 I think this is related to this core PR

CC @CatchABus

Actually, we used the same app to reproduce those but they are two different bugs.
This one needs a small correction on Vue side!

[dangrima90]

@dangrima90 I think this is related to this core PR

CC @CatchABus

Indeed it's two separate bugs. When I tested the sample application above with the draft fix in the linked PR I still replicate the Vue issue.