Plans to replace CodeGeneration.Roslyn dependency with Source Generators (introduced in .NET 5) in LanguageExt.CodeGen?

[Malgefor]

Hi!

I am using the LanguageExt.CodeGen package to generate Discriminated Unions. However, the dependency https://github.com/AArnott/CodeGeneration.Roslyn is marked as deprecated in the repo.

Are there plans to use the Source Generators (https://devblogs.microsoft.com/dotnet/introducing-c-source-generators/) for the CodeGen package?

Cheers

[Malgefor]

To elaborate a bit more on why the dependency on the deprecated package isn't great: if you want to run the codegen tool in your build you need to .NET Core 2.1 SDK installed on the machine / Docker image to be able to build. So when building a .NET 5 project, you still need 2.1.

If you don't have the 2.1 SDK you will get errors along the lines of:

.nuget/packages/codegeneration.roslyn.buildtime/0.6.1/build/CodeGeneration.Roslyn.BuildTime.targets(61,5): warning MSB3073: The command "dotnet codegen --version" exited with code 150.

.nuget/packages/codegeneration.roslyn.buildtime/0.6.1/build/CodeGeneration.Roslyn.BuildTime.targets(61,5): warning MSB4181: The "Exec" task returned false but did not log an error.

.nuget/packages/codegeneration.roslyn.buildtime/0.6.1/build/CodeGeneration.Roslyn.BuildTime.targets(73,5): error CGR1001: CodeGeneration.Roslyn.Tool (dotnet-codegen) is not available, code generation won't run. Please check https://github.com/AArnott/CodeGeneration.Roslyn for usage instructions.

To fix this you have to install the .NET Core 2.1 SDK, which goes out of support August 2021. (https://dotnet.microsoft.com/platform/support/policy/dotnet-core)

Example config of installing the 2.1 SDK in a Docker file: FROM mcr.microsoft.com/dotnet/sdk:5.0-focal AS build COPY --from=mcr.microsoft.com/dotnet/sdk:2.1-focal /usr/share/dotnet /usr/share/dotnet

[harrhp]

you should not need 2.1 sdk. try to define roll forward policy https://github.com/AArnott/CodeGeneration.Roslyn/issues/180#issuecomment-562895670

[Malgefor]

Ah you are right! Thanks for pointing that out : ) Missed that when I was trying to get the codegen tool to work.

[louthy]

Regarding the original question, yes, I will be updating the CodeGen to use Source Generators. I'm super overloaded with other projects at the moment, so I'm having to keep my interaction with LangExt at a minimum for a while, so it probably won't be for a month or so.

[gabomgp4]

you should not need 2.1 sdk. try to define roll forward policy

In my case, it was required to install the runtime 2.1. Installing the SDK was not enough.

[bmargula]

Hi, I'm totally new to LanguageExt and tried to setup the codegen functionality as mentioned in the wiki. But I do have the same problem as other in that I can't get it to work with my .NET6 SDK. I saw there was no activity here for 6 months. Is this still on the roadmap, @louthy ?

[StefanBertels]

@bmargula: Installing .NET 2.1 (SDK or runtime, don't know) on your developer machine (and your build server) should be enough to make codegen working as documented. This is not a runtime dependency for your binaries. Your project can target e.g. net60. It's working fine with latest LanguageExt, too.

[Malgefor]

you should not need 2.1 sdk. try to define roll forward policy AArnott/CodeGeneration.Roslyn#180 (comment)

Have you tried this? After I set the rollforwardpolicy as an environment variable it worked without having to install the 2.1 sdk/runtime