TUnit.Engine sets LangVersion=latest, overridding my repo policy

[AArnott]

I set LangVersion to 13 in my repo for all my projects. I prefer explicit versions set rather than latest so that the compilation output is the same regardless of SDK version or VS version installed on the machine.

tunit.engine.props overrides this property with latest, and doesn't give me an opportunity to disable this.

Perhaps you can add a property I can set to indicate I want project properties like this to be left alone.
Or maybe don't set it if it's already set.
Or maybe just produce a build error if it isn't set to a high enough value, so that users understand and can manage this property within their project file, as they are used to.

[thomhurst]

props should always be set before. Anything defined in projects themselves, or targets, should override props afaik?

[AArnott]

I set my LangVersion in Directory.Build.props, which comes before nuget package .props. So your package is overridding my repo-wide setting.
Setting LangVersion in .targets is too late. The .NET SDK copies the value from that property into other properties between the project file and user .targets files.
That leaves the project file itself. But I shouldn't have to set a property in my project file when my repo sets it, to set it back. If I do that, then I can't upgrade it at one central location any more.

[krafs]

Last I read using LangVersion=latest is discouraged anyway:

https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/configure-language-version

[viceroypenguin]

@thomhurst you should check the version instead of forcing latest. see https://andrewlock.net/creating-a-source-generator-part-12-reading-compilation-options-and-csharp-version-in-source-generators/ for example of how to do that.

[philipp-naused]

e.g.,

[Generator(LanguageNames.CSharp)]
public class MyGenerator : IIncrementalGenerator
{
    public void Initialize(IncrementalGeneratorInitializationContext context)
    {
        context.RegisterSourceOutput(context.ParseOptionsProvider, (sourceProductionContext, op) =>
        {
            if (op is CSharpParseOptions { LanguageVersion: < LanguageVersion.CSharp12 })
            {
                sourceProductionContext.ReportDiagnostic(Diagnostic.Create(Diagnostics.LangVersionMustBe12OrHigher, null));
            }
        });
    }
}

[thomhurst]

Hopefully the new version sorts this for you