Regression - Android - Exception thrown during NavigationPage.Navigation.PopAsync

[aquisio]

I am seeing an ArgumentOutOfRangeException when executing PopAsync after inserting a page into the navigation stack, which seems to be a regression of this issue and may be related to #2576 .

The issue can be reproduced by adding a single empty page to an empty template project and then including the following code in an async OnStart() implementation:

	var nav = (NavigationPage) MainPage;
	nav.Navigation.InsertPageBefore(new SecondPage(), nav.CurrentPage);
	await nav.Navigation.PopAsync(false);

This issue only affects Android projects using Material Design (FormsAppCompatActivity).

• Version with issue: All Xamarin.Forms versions from v2.5.1.444934 onwards
• Last known good version: v2.5.0.280555
• IDE: VS2017 v15.7.1
• Android Target Framework: 7.1, 8.0, 8.1
• Android Support Library Version: v25.4.0.2 and v27.0.2

StackTrace.txt
BugRepro.zip

[matteopiccioni]

I seriously believe that this situation is not acceptable...new and old bugs appear with each new release.
When the fix will be released?

[opcodewriter]

I hope this time unit tests are implemented, so that any further regression gets caught by CI

[rmarinho]

Hi @opcodewriter that's for your feedback it's hard to unit test platform code, the interation, time on device etc make it super hard. We do write UI Test, and i wrote one in my fix, that's how i found out this seems to be a issue also in iOS :)

[jefffhaynes]

This is happening for me as of 3.4.0.1008975

EDIT: Actually, it looks like it's a result of auto-navigating away from the page during an "Appearing" event, even though the stack indicates having pages available during pop.

The entire Navigation management system seems to be quite unstable.

[kwacks]

@jefffhaynes
Did you find a workaround to this issue or open another issue? I'm having the same issue - unable to pop after autonavigating in onAppearing