Source generators get the referencing project path - retrieve useful value from IncrementalValueProvider<string>

Question

In order to execute some logic with a source generator on some files (image files more precisely) based on the folders structure of the targeted/referencing project, I need to get the path/directory of the targeted/referencing project.

First approach

namespace SourceGen
{
    [Generator]
    public class Class1 : IIncrementalGenerator
    {
        public void Initialize(IncrementalGeneratorInitializationContext context)
        {
            var projDirectory = context.AnalyzerConfigOptionsProvider
                           .Select((x, _) => x.GlobalOptions
                           .TryGetValue("build_property.MSBuildProjectDirectory", out var projectDirectory) ? projectDirectory : null);

            File.AppendAllText("\\" + "log.txt", projDirectory );
        }
    }
}

I am logging to a file for debugging purposes (to check the property value I am reading in this case) since I can't find another way to debug this kind of project.

In the log file I get, since IncrementalValueProvider<string>.ToString() returns the type and not whatever value is there:

Microsoft.CodeAnalysis.IncrementalValueProvider`1[System.string].

Second approach

following https://stackoverflow.com/a/66548212:

var mainSyntaxTree = context.CompilationProvider.Select((x, _) => x.SyntaxTrees.First(x => x.HasCompilationUnitRoot));
var directory = Path.GetDirectoryName(mainSyntaxTree.Select((x, _) => x.FilePath);

The same issue Path.GetDirectoryName() is complaining that the provided parameter is of type IncrementalValueProvider<string> while expecting a string. Not sure how can I get a useful string value (FilePath) out of the type IncrementalValueProvider<string>.

Third approach

This time the log file was not written/created at all:

var provider = context.AnalyzerConfigOptionsProvider.Select((x, _) =>
       {
        x.GlobalOptions.TryGetValue("build_property.MSBuildProjectDirectory", out var projectDirectory);
       File.AppendAllText("\\" + "log.txt", "testing" + projectDirectory);
       return projectDirectory;
       });

Docs: https://github.com/dotnet/roslyn/blob/main/docs/features/incremental-generators.cookbook.md

What am I missing to make this work?

TylerH · Accepted Answer · 2025-05-05 19:02:50Z

0

The third approach is close; the return type is IncrementalValueProvider not the value itself. Then you need to combine this provider with another. I do it like this:

var someInfo = context.AnalyzerConfigOptionsProvider
    .Select(static (ctx, _) => { 
        if(ctx.GlobalOptions.TryGetValue("build_property.someInfo", out var info))
        {
            return info;
        }
        return defaultInfo;
    });

var dataFromAttribute = context.SyntaxProvider
    .ForAttributeWithMetadataName(
        "MyAttribute",
        predicate: static (s, _) => s is ClassDeclarationSyntax { AttributeLists.Count: > 0  },
        transform: static (ctx, _) => GetAttributeData(ctx.SemanticModel, ctx.TargetNode))
    .Where(static m => m is not null);

var attributeDataEnhancedWithInfo = dataFromAttribute .Combine(someInfo ).Select((pair, _) => {
    pair.Left!.Info = pair.Right;

    return pair. Left!});

edited May 5 at 19:02

TylerH

21.3k84 gold badges84 silver badges121 bronze badges

answered Aug 20, 2024 at 8:53

McMlok

5374 silver badges17 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Source generators get the referencing project path - retrieve useful value from IncrementalValueProvider<string>

First approach

Second approach

Third approach

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

First approach

Second approach

Third approach

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related