[Bug] UWP is throwing exception randomly after 4.8.0.1687 and VS 2019 16.8.1

[EmilAlipiev]

Description

After updating VS 2019 16.8.1 version. I am keep getting exception on the function shown below screenshot. This is happening in different places but mostly when i try to navigate between pages. GetXamlTypeByName(string typeName)
typeName is also different on the crash. I read somewhere that it is related to Uwp Hot reload added into this version and it was suggested that disable hot reload toolbar on top which i did but it didnt help. Still happening.

only message in the debug window is as below. I a worried that this is not VS related but with 4.8.0.1687 version.

Exception thrown: 'System.IO.FileNotFoundException' in System.Private.CoreLib.dll
An unhandled exception of type 'System.ExecutionEngineException' occurred in System.Private.CoreLib.dll

VS bug #1248154

[StephaneDelcroix]

@maxbrister does this ring a bell ??

[YZahringer]

Same random error on UWP after VS 16.8.1 update

[maxbrister]

Yes, this is a known issue with Uwp/Xamarin incremental hot reload.

Disabling the Uwp in-app toolbar should workaround the crash (uncheck Options->Debugging->Hot Reload ->Enable in-app toolbar). Unfortunately the underlying crash is caused by a core clr issue and apps making heavy use of reflection may experience issues. We are working on a fix for 16.9.

[EmilAlipiev]

I have that disabled on 16.8.1 and 16.9 pre. it fixes the issue on 16.9 pre but disabling doesnt help on 16.8.1 stable

[maxbrister]

Can you try adding the following to your Uwp project head?

<PropertyGroup>
  <EnableTypeInfoReflection>false</EnableTypeInfoReflection>
</PropertyGroup>

[jsuarezruiz]

@EmilAlipiev Could you try the latest suggestion from Max?

[YZahringer]

Build error with VS 16.8.2, disabling EnableTypeInfoReflection and UWP in-app toolbar:

\obj\x86\Debug\XamlTypeInfo.g.cs(117,43,117,49): error CS0234: The type or namespace name 'Markup' does not exist in the namespace 'Microsoft.UI.Xaml' (are you missing an assembly reference?)

[YZahringer]

Build error with VS 16.8.2, disabling EnableTypeInfoReflection and UWP in-app toolbar:

\obj\x86\Debug\XamlTypeInfo.g.cs(117,43,117,49): error CS0234: The type or namespace name 'Markup' does not exist in the namespace 'Microsoft.UI.Xaml' (are you missing an assembly reference?)

It works now with disabled EnableTypeInfoReflection, maybe some cache before. Restart VS and clean solution after change it.

[GitSicarius]

I disabled all of the UWP hot reload debug options and was still getting the ExecutionEngineException randomly. I then added <EnableTypeInfoReflection>false</EnableTypeInfoReflection> to my UWP csproj and haven't had any exceptions.

[EmilAlipiev]

question is if that is effecting Release mode as well?? or it is just debug issue. Do i need this EnableTypeInfoReflection = false when i want to make a new release?

[GitSicarius]

That's a good question. I'm also concerned with adding a new csproj tag not fully understanding the side effects.

[bmacombe]

I've not had any problems with my release builds, it's only with the debugger attached since it's related to Hot Reload

[bmacombe]

also, I can run my debug builds without the debugger attached and I don't receive the error.

[maxbrister]

EnableTypeInfoReflection changes Uwp's auto generated XamlTypeInfo.g.cs to use reflection instead of a compile time generated table. The generated file should be under your obj folder. It is intended to make Uwp hot reload a smoother experience. By default EnableTypeInfoReflection is not enabled in release builds.

[EmilAlipiev]

are you able to run your app in release mode? For me my app is no longer running in release. i am getting all the time Unhandled exception at 0x00007FFA71E23B29 (KernelBase.dll) in error. I have 0 change in platform level since last successful running version. i have also recognized that in release mode app is starting very fast like debug mode. There is surely something wrong with this VS 2019 version 16.8.3

[EmilAlipiev]

this still exist in the latest Vs2019 and XF5 it makes hot reload unusable for uwp xamarin

in VS19 16.8.4 even worse whenever i start my application it throws this exception. it seems to be Hot reload is crashing

[EmanterolaDN]

Thanks @maxbrister and @jsuarezruiz this workaround worked for me with XF 5 and VS 16.8.4. I just hope this fix won't affect to Release... I'll keep in touch!

[hupo376787]

16.8.4, still facing the problem.

[LyalinDotCom]

Sorry for everyone having this issue. An update on the situation is that we've got a tooling fix in 16.9 Preview 4+, but it depends on a related fix that lives inside of the .NET Native NuGet package which is also going to be released soon and is required to make this error finally go away.

Once both things are available, and your projects are updated then this issue should be fully resolved.

Thank you for your patience and for now there is a workaround above that should work.

[maxbrister]

Microsoft.NETCore.UniversalWindowsPlatform 6.2.12 is now available and contains a fix for the ExecutionEngineException. If you're on the preview channel after updating to 16.9 Preview 4 you should be prompted to update your NuGet package on F5. If you're on 16.8 you will need to update Microsoft.NETCore.UniversalWindowsPlatform via the NuGet package manager.

@hupo376787, @EmanterolaDN, @EmilAlipiev, @MattRames can you guys undo your workarounds and give this a try?

[EmanterolaDN]

Thank you @maxbrister and all the people involved, we'll include in our app ASAP, @juanmalm

[ginomessmer]

Hi @maxbrister, I've had the same issue and I've been following this issue ever since then. I can confirm that the issue is gone on my end. Thank you for providing the fix!

[StephaneDelcroix]

closing per @maxbrister request

[EmilAlipiev]

@maxbrister Unfortunately not working for me when I enable hotreaload as below. I updated to 6.2.12 and VS 2019 16.8.5. it is still throwing similar exception even on start up now.

Exception:

System.NullReferenceException
  HResult=0x80004003
  Message=Object reference not set to an instance of an object.
  Source=Xamarin.HotReload.Forms
  StackTrace:
   at Xamarin.HotReload.Forms.VisualTreeService.VisualTree.FormsVisualTreeContext.SubscribeToVisualTreeChanges()
   at Microsoft.VisualStudio.DesignTools.TapContract.Networking.ProtocolHandler.<>c__DisplayClass28_0`1.<RegisterMessageObserver>b__0(TMessage message)
   at Microsoft.VisualStudio.DesignTools.TapContract.Networking.ProtocolHandler.HandleMessage[TMessage,TReply](Func`2 callback, Message request)
   at Microsoft.VisualStudio.DesignTools.TapContract.Networking.ProtocolHandler.ProcessInboundMessage(Message message)
   at Microsoft.VisualStudio.DesignTools.TapContract.Networking.ProtocolHandler.ActionThread(Object list)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()

  This exception was originally thrown at this call stack:
    Xamarin.HotReload.Forms.VisualTreeService.VisualTree.FormsVisualTreeContext.SubscribeToVisualTreeChanges()
    Microsoft.VisualStudio.DesignTools.TapContract.Networking.ProtocolHandler.RegisterMessageObserver.AnonymousMethod__0(TMessage)
    Microsoft.VisualStudio.DesignTools.TapContract.Networking.ProtocolHandler.HandleMessage<TMessage, TReply>(System.Func<TMessage, TReply>, Microsoft.VisualStudio.DesignTools.TapContract.Networking.Message)
    Microsoft.VisualStudio.DesignTools.TapContract.Networking.ProtocolHandler.ProcessInboundMessage(Microsoft.VisualStudio.DesignTools.TapContract.Networking.Message)
    Microsoft.VisualStudio.DesignTools.TapContract.Networking.ProtocolHandler.ActionThread(object)
    System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, object)
    System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()

[EmilAlipiev]

I guess that it is about Live VisualTree. When i disable it, works fine.

Exception is thrown even if i disable Live VisualTree

[maxbrister]

@EmilAlipiev that's a different issue. I think the problem you're running into now is Application.Current is null when the tooling tries to initialize. Assuming Application.Current is eventually initialized in your app, you should be able to workaround the issue by doing cntrl+F5 then attaching to the application after it is initialized.

[hupo376787]

Hi, I'm still facing An unhandled exception of type 'System.ExecutionEngineException' occurred in System.Private.CoreLib.dll.

Microsoft Visual Studio Professional 2019
Version 16.9.1
VisualStudio.16.Release/16.9.1+31105.61
Microsoft .NET Framework
Version 4.8.04084

Windows Template Studio   3.9.20351.2
Windows Template Studio quickly builds a UWP app, using a wizard-based UI to turn your needs into a foundation of Windows 10 patterns and best practices.

[maxbrister]

@hupo376787 can you provide a heap dump of your application when it is crashed? You can generate one in VS using Debug -> Save Dump As....

[hupo376787]

Hi, @maxbrister I met this twice today, and the dump file is in https://github.com/hupo376787/System.ExecutionEngineException/releases/download/1.0/test.zip.
Thx.

[maxbrister]

@hupo376787 from your dump it looks like your app is a normal Uwp app not a Xamarin Forms app. Is that correct?

There's a good chance you're running into the same underlying bug. If you update the Microsoft.NETCore.UniversalWindowsPlatform NuGet package for your project does that fix the issue?

[hupo376787]

Yes, it's a pure uwp app. I will update and try, thanks.@maxbrister