[Bug] Compiling XCT-Popups-Samples causes a Invalid Cast Exception in UWP Native Compilation

[inforithmics]

Description

Steps to Reproduce

1. Get https://github.com/ahoefling/XCT-Popups-Samples
2. Set To Release / x64 and select UWP as startup
3. Start Project (Clicking on the Button causes a crash)

Expected Behavior

Does not crash in the Native Compiled UWP app

Actual Behavior

Does crash

Basic Information

• Xamarin Community Toolkit Version UWP Version 1.1.0

Workaround

Only start in Debug Mode

Pull Request

This Checkin Fixes it

e85895d

[inforithmics]

I think the the UWP Native Compiler somehow breaks Type inheritence and therefore Types that are assignable aren't after Release Compile. That's why it works in the Debug mode but not in Release Mode.

In the checkin I create the Renderer in Xamarin Community Toolkit UWP. And then it works. (Trial and Error)

[TheCodeTraveler]

@ahoefling Can you confirm this?

[SkyeHoefling]

I'm on family leave until June, won't be able to look at this until then

[phandcock]

Hi, this is an issue with my UWP store app. I have put in a workaround to ignore the InvalidCastException until it is fixed.

[pictos]

@phandcock can you share your workaround?

[phandcock]

Workaround is too strong a term. More like, swallow the exception and accept that the popup will not be displayed. A pain but I am not good enough to fix it myself.

The code is:

try
{
DataLog.PopupDismissFlag = false;

                // TODO Ignore exception. See https://github.com/xamarin/XamarinCommunityToolkit/issues/1251
                var popup = new MessageLog();

                var t = Application.Current.MainPage.Navigation.ShowPopupAsync(popup);
            }
            catch (InvalidCastException)
            {
                // TODO fix UWP Release issue until fixed
            }

[inforithmics]

In the pull #1247 request I discovered this exact problem

And this commit "fixes" the problem

e85895d

I think the underlaying problem is a Code Optimization Bug in in the Native Compiler.

[inforithmics]

The nuget with this fix can be downloaded here

https://dev.azure.com/xamarin/public/_build/results?buildId=40249&view=artifacts&pathAsName=false&type=publishedArtifacts

[phandcock]

It works! You sir, as my father would have said, are a gentleman and a scholar.

I am setting up a new release now. Thank you.

[SkyeHoefling]

@brminnick @inforithmics
Thanks for being patient while I was away on family leave. I have commented my thoughts on the PR. Thanks for all the investigation on this issue, seems like UWP is doing some funky things in release mode

[phandcock]

Still seems to be an issue in Release 1.2 which is not unexpected as its still open and not referenced in the Release notes :-)

Version 1.1.0-preview2508 still works.