C# Incremental Source Generator Not Triggering build when generated files are modified

Question

I have 2 projects, IE: projX.csproj and projY.csproj.

My src generator is referenced by projX, but the code generated is based on classes on projY.

When projY classes change, the generated files should change (and they do), but because no change occurs on projX, the changes are not picked up and no build occurs on projX. Routes that I'm considering but can't find an answer for:

1. How do I make projX recognize that the generated files have changed?
2. Otherwise, how can I force projX to build when projY changes?

Thank you.

Answer 1

The best workaround I found for this particular scenario is to add:

<ItemGroup>
    <Compile Include="../YourProjectName/*/*.cs"/>
</ItemGroup>

What's passed in the include depends on the case, but best to be as specific as possible. That will add the syntax tree to the compilation as well.

Answer 2

This was too long for a comment.

One thing i think it might be at this point is that you're getting the type the wrong way, I use this to get values from Expressions passed to the attribute. it's actually not working for DefaultExpressionSyntax at the moment, that's why I'm useing NamedParameters in the attribute, to avoid it:

public record ValueSymbolInfo(object? Value, TypeInfo? Type);
private ValueSymbolInfo GetValue(SemanticModel semanticModel, ExpressionSyntax expression)
{
    var constantType = semanticModel.GetTypeInfo(expression);
    if (expression is TypeOfExpressionSyntax typeOfExpressionSyntax)
        return new(GetValue(semanticModel, typeOfExpressionSyntax.Type).Type, constantType);
    if (expression is DefaultExpressionSyntax defaultExpressionSyntax)
        return new(null, GetValue(semanticModel, defaultExpressionSyntax.Type).Type);
    if (expression is ArrayCreationExpressionSyntax arrayCreationExpressionSyntax)
    {
        var initializer = arrayCreationExpressionSyntax.Initializer;
        var type = semanticModel.GetTypeInfo(arrayCreationExpressionSyntax.Type);
        if (initializer is null)
        {
            return new(null, type);
        }
        else
        {
            var expressions = initializer.Expressions;
            var value = expressions.Select(syntax => GetValue(semanticModel, syntax)).Select(info => info?.Value).ToArray();
            return new(value, type);
        }
    }
    var constantValue = semanticModel.GetConstantValue(expression);
    return new(constantValue.HasValue ? constantValue.Value : default, constantType);
}

If used on typeof(ProjYType) it should return the TypeInfo of the referenced type as Value and the TypeInfo of System.Type as Type

otherwise i could only imagine something to be wrong with your project files.