#8261 - terminating WinUIComposition loop on process exit to avoid cr…

[HermanKirshin]

…ashes

What does the pull request do?

Infinite message loop is terminated on process exit, so WinUIComposition native code does not attempt to assess managed code during cleanup.

What is the current behavior?

In some cases process crashes on exit, see bug for details

Fixed issues

Fixes #8261

[dnfadmin]

All CLA requirements met.

[avaloniaui-team]

You can test this PR using the following package version. 11.0.999-cibuild0023982-beta. (feed url: https://nuget.avaloniaui.net/repository/avalonia-all/index.json) [PRBUILDID]

[kekekeks]

I suspect that we need to make the thread non-background too -

Avalonia/src/Windows/Avalonia.Win32/WinRT/Composition/WinUICompositorConnection.cs

Line 83 in a09db71

IsBackground = true

[HermanKirshin]

With non-background thread it will hang process, because ProcessExit event will not be triggered and this cancellation token will not be switched. For non-background thread cancellation token should be triggered from somewhere else i.e. when UIThread dispatcher's main loop ends. I tried to find some way how to link UIThread loop end and WinUICompositorConnection, but it led to many doubtful changes.

[kekekeks]

Let's try to merge as is, and see if the problem persists in some cases (I suspect there can be a rare race condition).