Document handling uncaught exceptions in WinUI 3 applications with AOT enabled

[jamescrosswell]

To get trimming working we had to remove some code that used reflection to automatically register an unhandled exception handler in WinUI applications, if Trimming is enabled (typically when doing AOT compilation). Further details in #2732

This means we have to document how users can send unhandled exceptions to Sentry
- getsentry/sentry-docs#8557
- getsentry/sentry-docs#8602

[tipa]

Interested in the guidance. Currently I am using the snippet below, which seems to work. Is it the right way to do it?

UnhandledException += (s, e) =>
{
    e.Exception.SetSentryMechanism(
        "Microsoft.UI.Xaml.UnhandledException",
        "This exception was caught by the Windows UI global error handler. " +
        "The application likely crashed as a result of this exception.",
        e.Handled);
    Sentry.SentrySdk.CaptureException(e.Exception);
    Sentry.SentrySdk.Flush();
};

[jamescrosswell]

Interested in the guidance. Currently I am using the snippet below, which seems to work. Is it the right way to do it?

What we have in Sentry 3.x is the reflection based equivalient of this:

• sentry-dotnet/src/Sentry/Integrations/WinUIUnhandledExceptionIntegration.cs

  Line 81 in 343d921

  // Microsoft.UI.Xaml.Application.Current.UnhandledException += WinUIUnhandledExceptionHandler;

The exception handler it wires up is a bit more convoluted. In addition to what you're doing, there's a workaround for not sending through a stack trace, in some circumstances, setting a mechanism and also flushing events in the face of an irrecoverable error... but broad strokes, it looks like what you're doing is all good.

This issue (once completed) should provide a way for you to hook up the WinUIUnhandledExceptionHandler that we provide... currently this is private, so there's no easy way to do this. If you don't have any urgent issues with your current solution then, I'd say keep it how it is and, in a few weeks, we'll provide a way for you to point unhandled exceptions at Sentry's event handler (so one less thing for you to maintain).

[bruno-garcia]

This WinUI stuff done with reflection was a hack originally done because stuff in .NET was broken. Did they fix this in the latest versions?

[jamescrosswell]

This WinUI stuff done with reflection was a hack originally done because stuff in .NET was broken. Did they fix this in the latest versions?

Is this related?

• Application.UnhandledException strips Message and StackTrace microsoft/microsoft-ui-xaml#7160

[bruno-garcia]

I assume so, not sure.

Could we get away without the hack and just document this?

Troubleshooting page:

WinUI customers on version of WinUI below XYZ: ...