ArgumentOutOfRangeException in Android NavigationPageRenderer

[radioactiveman]

Description

Our crash reports contain an unhandled ArgumentOutOfRangeException in the Android NavigationPageRenderer. Unfortunately I could never reproduce the crash myself.

Stacktrace.txt

I guess this exception occurs here in line 621 because there is no check if the collection is empty. My suggestion is to use FirstOrDefault() with a null check.

Steps to Reproduce

Unknown

Expected Behavior

No unhandled exception causing a crash.

Actual Behavior

App crashes.

Basic Information

• Version with issue: 3.2.0.839982
• Last known good version: Unknown
• IDE: Visual Studio 2017
• Platform Target Frameworks:
  • Android: 7.0
• Android Support Library Version: 27.0.2.1
• Affected Devices: Multiple vendors and devices, Android 6 - 8

[samhouts]

Are you able to provide any more context into the structure of your app? Are you using a MasterDetailPage? Modal pages? Do you change the MainPage of your app at any time? Thanks!

[radioactiveman]

The app uses MvvmCross with its NavigationService to do all the navigation. We use neither master detail pages nor modal pages.

[radioactiveman]

@hartez Any update on this issue? Your changes in #4132 are only relevant for Android, how can they make iOS tests fail? Are they not false positives?

[hartez]

The changes aren't making the iOS tests fail; the new test doesn't pass on iOS. And that's because it shouldn't - the whole situation is invalid. A NavigationPage should never be in a situation where it's visible and does not have a root page.

So the actual bug isn't the lack of a null check; something else is going wrong to cause this situation.

Which version of MvvmCross does your application use? Are you using the MvxPagePresentationAttribute WrapInNavigationPage or NoHistory options?

[radioactiveman]

Thanks for the fast answer. The relevant version of the app uses MvvmCross 5.7.0.
We released a new version recently and updated MvvmCross to 6.2.2.
So far we have no crash reports about this anymore. I will keep an eye on it and reopen this issue if required.

[hartez]

I'm wondering if this and #4708 might be related.