Add support for jump-to-def for associations

[maxveldink]

Closes #358

Adds support for jump to definition for belongs_to, has_one, has_many and has_and_belongs_to_many associations on models.

[maxveldink]

I have signed the CLA!

[andyw8]

👋 Looking into the on_class_node_enter problem.

[andyw8]

Ah, we don't need to listen for class node events, we can use the nesting:

model_name: @nesting.join("::")

[andyw8]

I notice the Builder classes (example) are marked :nodoc: which usually means they should treated as internal, so we may need to add a public interface for that in Rails.

[maxveldink]

Thanks @andyw8! I'm flipping this to ready since it's about good from my end. Ready to review whenever!

How do I go about upstreaming the behavior we need for the Builder classes? Can we merge this with the private interfaces if we have the next steps for a better interface?

[maxveldink]

I'm not sure the right behavior here; I opted to return the error message; but I think would could return a nil result just like when the model name doesn't resolve properly. Thoughts?

[andyw8]

Yeah, I think returning nil is more appropriate here.

Thinks make me think though: Sometimes it's confusing for the user if they try something and the editor seems to do nothing. Perhaps there could be an info response, which prints something to the log in these kinds of situations.

[maxveldink]

Switched it to nil for now. I like the idea of having info responses print to the log. Should we add an issue to add that support?

[andyw8]

Nice!

I found there's a simpler way than using the Builder classes - reflect_on_association It will also work with options, e.g. class_name, and it's documented so there's no concerns about using private APIs.

I branched off your PR and added a couple of commits in this branch:

https://github.com/Shopify/ruby-lsp-rails/compare/andyw8/go-to-def-assoc

If you want to update your branch then go ahead, otherwise I can things over from here.

[maxveldink]

@andyw8 Thanks! I was looking for a more stable way too and this works great.

I pulled in your commits and cleaned up the PR some more. Should be good for another look

[vinistock]

Just a couple of comments. This looks great!

[vinistock]

Looks good to me, but linting is failing

[maxveldink]

@vinistock Ahh yes, GH PR additions always get me. Should be good to go 👍🏻

[andyw8]

btw we're starting on fixing the target behaviour so you'll be to right click on the symbol rather than the has_many (etc.): Shopify/ruby-lsp#2099