NullReferenceException inside AvaloniaUI

[ajayre]

I set a breakpoint on the following line in my code. When I step over it I get a null reference exception:

HttpResponseMessage Response = await Client.GetAsync(Url);

where Client is HttpClient. However the stack trace shows it is inside the Avalonia animation code and doesn't even show in the stack the function containing the above code.

There is no inner exception. I can reproduce this 100% of the time.

How can I debug this further?

Thanks, Andy

Avalonia.Base.dll!Avalonia.Animation.AnimationInstance<double>.InternalStep(System.TimeSpan time)	Unknown
Avalonia.Base.dll!Avalonia.Animation.AnimationInstance<double>.Step(System.TimeSpan frameTick)	Unknown
Avalonia.Base.dll!Avalonia.Reactive.LightweightObservableBase<System.TimeSpan>.PublishNext(System.TimeSpan value)	Unknown
Avalonia.Base.dll!Avalonia.Animation.ClockBase.Pulse(System.TimeSpan systemTime)	Unknown
Avalonia.Base.dll!Avalonia.Media.MediaContext.RenderCore()	Unknown
Avalonia.Base.dll!Avalonia.Media.MediaContext.Render()	Unknown
Avalonia.Base.dll!Avalonia.Threading.DispatcherOperation.InvokeCore()	Unknown
Avalonia.Base.dll!Avalonia.Threading.DispatcherOperation.Execute()	Unknown
Avalonia.Base.dll!Avalonia.Threading.Dispatcher.ExecuteJob(Avalonia.Threading.DispatcherOperation job)	Unknown
Avalonia.Base.dll!Avalonia.Threading.Dispatcher.ExecuteJobsCore(bool fromExplicitBackgroundProcessingCallback)	Unknown
Avalonia.Base.dll!Avalonia.Threading.Dispatcher.Signaled()	Unknown
Avalonia.Win32.dll!Avalonia.Win32.Win32Platform.WndProc(nint hWnd, uint msg, nint wParam, nint lParam)	Unknown
[Native to Managed Transition]	
[Managed to Native Transition]	
Avalonia.Win32.dll!Avalonia.Win32.Win32DispatcherImpl.RunLoop(System.Threading.CancellationToken cancellationToken)	Unknown
Avalonia.Base.dll!Avalonia.Threading.DispatcherFrame.Run(Avalonia.Threading.IControlledDispatcherImpl impl)	Unknown
Avalonia.Base.dll!Avalonia.Threading.Dispatcher.PushFrame(Avalonia.Threading.DispatcherFrame frame)	Unknown
Avalonia.Base.dll!Avalonia.Threading.Dispatcher.MainLoop(System.Threading.CancellationToken cancellationToken)	Unknown
Avalonia.Controls.dll!Avalonia.Controls.ApplicationLifetimes.ClassicDesktopStyleApplicationLifetime.StartCore(string[] args)	Unknown
Avalonia.Controls.dll!Avalonia.Controls.ApplicationLifetimes.ClassicDesktopStyleApplicationLifetime.Start(string[] args)	Unknown
Avalonia.Controls.dll!Avalonia.ClassicDesktopStyleApplicationLifetimeExtensions.StartWithClassicDesktopLifetime(Avalonia.AppBuilder builder, string[] args, System.Action<Avalonia.Controls.ApplicationLifetimes.IClassicDesktopStyleApplicationLifetime> lifetimeBuilder)	Unknown
MyApp.dll!MyAPp.Program.Main(string[] args) Line 12	C#

[maxkatz6]

Should be fixed by #20422

[ajayre]

Thanks!