.NET Core v2.1 SDK broke RazorLight in console app

[HakanL]

I was using RazorLight fine in VS2017 with .NET Core 2.0. I've tested to upgrade to .NET Core 2.1 SDK (so it's building using .NET Core 2.1 RC1, but also tested with the release of 2.1, same issue) and that broke my console app when calling CompileRenderAsync. It still works if I call this from a ASP.NET Core project type (which is targeting .NET Core 2.0). I have PreserveCompilationContext in the csproj set to true, but still getting this:

Failed to compile generated Razor template:
- (3:35) The type 'Attribute' is defined in an assembly that is not referenced. You must add a reference to assembly 'System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e'.
- (3:63) Predefined type 'System.String' is not defined or imported
- (3:76) Predefined type 'System.Type' is not defined or imported
- (3:10) Predefined type 'System.Void' is not defined or imported
- (11:37) The type 'Object' is defined in an assembly that is not referenced. You must add a reference to assembly 'System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e'.

(and 100s more of these)

I saw this issue, but I'm not 100% sure it's related: dotnet/sdk#2092. To me it seems something in the build process has changed, but I don't know if it's a known issue or if there is a fix.

[Shaddix]

we are having exactly the same error from our xunit tests

[toddams]

RazorLight is not tested on .NET Core 2.1, as it has just released recently

I will save this issue to avoid duplicates

[HakanL]

FYI, it happens both in the RC1 (maybe previews as well) and in the 2.1 release.

[superjulius]

FYI- I created an empty Net Core 2.1 App making few simple calls to RazorLight 2.0.0-beta1 and it is working fine.

We have seen similar issue with .Net Core 2.0 app though with SDK 2.1.300. The issue occurs after we removed the AssetTargetFallback attribute from the csproj.

Adding it back with $(AssetTargetFallback) value solved our problem.

[HakanL]

I don't have the fallback attribute in my project files (also compiling works fine so doesn't seem to be related). I get a runtime error when calling CompileRenderAsync from a string (which is a cshtml file). It works when I built this using .NET Core SDK 2.0, but with the 2.1 SDK it doesn't work any more, doesn't matter if I set the target to 2.0 or 2.1, it seems that the 2.1 build system does things differently that isn't working with RazorLight.

[willseward]

Is there a reliable work-around for this?

[superjulius]

@HakanL This is odd. I checked again and it is working on my end using SDK v2.1.300.

Happy to share the project code or try running a test project too

[willseward]

@superjulius I'm running my RazorLight in a separate class library. I'll do some tests to see if that's the determining factor for this bug.

[willseward]

Ok. Well, 2.1.300 seems to work fine! It only works on Windows. Linux/Docker does not work.

[HakanL]

Hmm, of course it works when I create a new solution (with RazorLight in a referenced project). I've compared the csproj files and they seem to match. (I'm on Windows). I guess I need to tinker around with it some more to figure out what's different. BTW, what does the error messages mean, that it can't find System assemblies or something?

[willseward]

I don't have the exact stack trace, but I'm guessing it has something to do with the compilation step: https://github.com/toddams/RazorLight/blob/master/src/RazorLight/Compilation/RoslynCompilationService.cs#L172. I assume that the DLLs that it needs are just missing at runtime!?

[willseward]

@HakanL FWIW: I was able to resolve the issue by deploying a framework-dependent binary, (not using -r linux). Hope this helps.

[HakanL]

I get the error even in debug (Visual Studio 2017) in Windows. But it's interesting that it works in a new console project, I need to break apart my larger app and see where it's failing.

[eric-swann-q2]

I'm struggling with this same issue...was there any resolution?

[IndexOverflow]

+1. Seeing this with the FluentEmail package which depends on RazorLight.