ActionRegistrationSourceGenerator poor performance

[AlmightyLaxz]

I have a .NET 10.0 Godot 4.5 project which is hit very hard by the ActionRegistrationSourceGenerator. It adds nearly 10 seconds to build times in my somewhat sizeable project.

I've done some tests with Stopwatch and found this part in ActionRegistrationSourceGenerator.cs seems to be the culprit:

var actions = new List<YarnAction>();
foreach (var tree in compilation.SyntaxTrees)
{
    actions.AddRange(Analyser.GetActions(compilation, tree, output).Where(a => a.DeclarationType == DeclarationType.Attribute));
}

As is, the performance impact of this generator is a bit of a deal breaker for using this addon personally.

Perhaps the ActionRegistrationSourceGenerator could be replaced with an incremental source generator without the file IO and Directory usage?

[dogboydog]

Thanks for the research and report. I think your suggestion to rework to an incremental source generator would help. I will look into this when I can.

[dogboydog]

This isn't a fix / rewrite of the source generation that would be required to close the issue, but this info might be relevant to those who are experiencing slow compile times due to source generation: #118 introduces a define symbol YARN_SOURCE_GENERATION_DISABLE_ALL which can be added to your .csproj file. This will prevent you from using the [YarnCommand] and [YarnFunction] attributes and require manual command and function registration to each dialogue runner, but it skips all of the crawling of assemblies for these attributes so it might be a good tradeoff for some.