How do I trigger a source generator from a *.razor file?

[MulletPr00f]

As the title says, I'm trying to figure out how to trigger a call to my ISourceGenerator implementation when I modify and save a *.razor file. As of now, I've only managed to trigger it when I modify and save a *.cs file.

[333fred]

Well, first and foremost, you shouldn't be using ISourceGenerator. You should be using IIncrementalGenerator, see https://github.com/dotnet/roslyn/blob/main/docs/features/incremental-generators.md and https://github.com/dotnet/roslyn/blob/main/docs/features/incremental-generators.cookbook.md. In an incremental generator, you'd base your generator on the additional files provider, and go from there.

[MulletPr00f]

@333fred what concerns me is that this option affects all generators, not only mine. I'm writing this generator to a team of 150+ developers, so if it starts to slow down their coding environments, I'm gonna hear it. On top of that, it wouldn't be very nice to remind all of the them to change this setting.

So yes, I'd like open an issue for future investigation, please.

[333fred]

so if it starts to slow down their coding environments, I'm gonna hear it

If it does, you can encourage them to file feedback. However, we've generally noticed that people don't actually care that their source generators are a tiny bit out of date until a file is actually saved, and by reducing the amount of working happening in the background, we significantly improve the rest of the experience of using VS by simply making that faster. The lack of saving a razor file triggering a rebuild in balanced mode is a bug, so feel free to open one for that.

[jasonmalinowski]

So saving additional files should be triggering generators in even balanced mode:

roslyn/src/VisualStudio/Core/Def/ProjectSystem/VisualStudioWorkspaceImpl_SourceGenerators.cs

Lines 68 to 70 in 7b7951a

	// Note: this will find docs, additional docs, and analyzer config docs. Thats good. We do want changing
	// any of those to cause rerunning generators in any affected project.
	var documentIds = _workspace.CurrentSolution.GetDocumentIdsWithFilePath(moniker);

If we're not seeing that, then yes please do file a bug.

[CyrusNajmabadi]

@jasonmalinowski this was a recent bug fix to support saving additional files. Previously, we only hooked up to actual Roslyn docs (c#/vb etc)

[333fred]

Looks like this was added to 17.12. @MulletPr00f, are you using 17.11? If so, then this is already fixed when you upgrade to 17.12 later this year.

[jasonmalinowski]

And it looks like the changes should already be in 17.12 Preview 1; @MulletPr00f if you want to try that that'll verify we're already fixed.

[MulletPr00f]

@CyrusNajmabadi Great!

@333fred Yes, I'm using 17.11.4.

@jasonmalinowski Alright, I'm gonna try that, and I'll get back to you to tell if the fix worked.

Thanks.

[MulletPr00f]

And it looks like the changes should already be in 17.12 Preview 1; @MulletPr00f if you want to try that that'll verify we're already fixed.

Confirmed it's working in 17.12.0 Preview 2.0! Can I mark all your three answers as the discussion answers?