Reactive: Compatibility with .Net5.0 Preview 6 and beyond

[jtbrower]

Feature request

Today I upgraded a large effort of mine to .Net5.0 Preview 6 and immediately ran into a compatibility issue that I have a hunch might be related to WinRT being removed from the .Net runtime. Below you will see the package versions I am using along with a stack trace caused by a missing System.Runtime.InteropServices.WindowsRuntime Version=4.0.3.0. What timeframe could one expect to see a compatible version of these libraries released by?

Packages

    <PackageReference Include="System.Reactive" Version="4.4.1" />
    <PackageReference Include="System.Reactive.Linq" Version="4.4.1" />

Stack Trace

System.IO.FileNotFoundException: Could not load file or assembly 'System.Runtime.InteropServices.WindowsRuntime, Version=4.0.3.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified.
File name: 'System.Runtime.InteropServices.WindowsRuntime, Version=4.0.3.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'
   at System.Reactive.ReflectionUtils.GetEventMethods[TSender,TEventArgs](Type targetType, Object target, String eventName, MethodInfo& addMethod, MethodInfo& removeMethod, Type& delegateType, Boolean& isWinRT)
   at System.Reactive.Linq.QueryLanguage.FromEventPattern_[TSender,TEventArgs,TResult](Type targetType, Object target, String eventName, Func`3 getResult, IScheduler scheduler) in /_/Rx.NET/Source/src/System.Reactive/Linq/QueryLanguage.Events.cs:line 263
   at System.Reactive.Linq.QueryLanguage.FromEventPattern_[TEventArgs](Object target, String eventName, IScheduler scheduler) in /_/Rx.NET/Source/src/System.Reactive/Linq/QueryLanguage.Events.cs:line 172
   at System.Reactive.Linq.QueryLanguage.FromEventPattern[TEventArgs](Object target, String eventName) in /_/Rx.NET/Source/src/System.Reactive/Linq/QueryLanguage.Events.cs:line 160
   at System.Reactive.Linq.Observable.FromEventPattern[TEventArgs](Object target, String eventName) in /_/Rx.NET/Source/src/System.Reactive/Linq/Observable.Events.cs:line 648

[tebeco]

Hello,

Here are some leads that were found related to the issue:

Similar issue impacted RX too in dotnet/runtime
https://github.com/dotnet/runtime/issues/37638

Someone linked that to this change:
https://github.com/dotnet/runtime/issues/37672

with reference to these docs / changes
https://github.com/dotnet/runtime/issues/35318
https://docs.microsoft.com/en-us/windows/uwp/csharp-winrt/
https://github.com/dotnet/docs/issues/18875

[tebeco]

I wonder if it's possible to get an intermediate release of dotnet/reactive removing WinRT from the code base during the transition
And re-adding support later on as a minor

I have no idea if this is something possible or not to be honest

[clairernovotny]

We will get an update out that supports .NET 5 out shortly.

[jtbrower]

Finally someone responded! :)

[tebeco]

1291

[clairernovotny]

Correct. We're currently blocked on build pipelines. Working on it.

[clairernovotny]

Please try out https://www.nuget.org/packages/System.Reactive/5.0.0-preview.16 and open specific issues as needed.