Configure initializationOptions per project

[rbartlensky]

Hi!

I am trying to implement a way to have eglot read a file, like .dir-locals.el, but for initializationOptions.

I have attempted to implement this in rustic (PR), but the author suggested that maybe this can become an eglot feature.

My usecase is that I want to configure rust-analyzer on a per-project basis. Since rust-analyzer can only be configured via initializationOptions, there is no way to currently add the desired options into something like .dir-locals.el. Do you have any thoughts on this?

[joaotavora]

Hello, If rust-analyzer can indeed only read project-specific data via `initializationOptions` (and not something more usual such as workspaceConfiguration) then your best option is to set eglot-server-programs directory-locally. In each directory where you need a different rust-analyzer initialization, set eglot-server-programs for 'rust-mode' in a way that includes a :initializationOptions (presumably a slightly different one for each project). See the https://joaotavora.github.io/eglot/#Setting-Up-LSP-Servers Hopefully it is clear what the "JSON object" is there. It's constructed in a syntax identical to the one used for workspaceConfiguration, which is described later in the manual. João

[rbartlensky]

Hi,

Thank you for getting back to me so quickly! One thing I'm unsure of is the "directory-locally" part. Could you elaborate on that please?

My hope is that whatever solution we come up with would benefit not just me, but anyone using eglot. I would like to find a way to check the initializationOptions for an LSP server into git and have other people that use eglot be able to seamlessly get the benefits without having to come up with their own logic to load them. At the moment, you could achieve something similar if you used .dir-locals.el (but only for workspaceConfigurations), hence why I am trying to go down this route.

Robert

[joaotavora]

"Directory-locally" means "using dir-locals.el"! Use that file to set the variable eglot-server-programs like i described (:initializationOptions is supported in its syntax, as the manual link explains). Check that it works, then check the file into Git.

[rbartlensky]

Ah I've never heard about dir-locals before, hence my confusion! Are you suggesting something like:

((rustic-mode
  . ((eglot-server-programs . (rustic-mode . ("rust-analyzer" :initializationOptions (...)))))))

I've had some success with this, however I had to put in my emacs config that eglot-server-programs can be safely overriden by dir-locals.el. Is that expected? If I don't add that I just get something like "attempted to use minibuffer while using the minibuffer" which I couldn't get past even with recursive minibuffers.

Thanks again, sorry for the late reply!

[joaotavora]

Ah I've never heard about dir-locals before,

In your very first sentence to this discussion you named this file!

Yes you need the safety switch. If you add that to your configuration it's a one time thing.

I don't understand the relation to recursive mini buffers.

I would follow @nemethf advice and try to use workspaceComfiguration instead of this technique.

[rbartlensky]

In your very first sentence to this discussion you named this file!

I thought it's specific to eglot that's what I meant. I didn't know you could use dir-locals outside of eglot.

Yes you need the safety switch. If you add that to your configuration it's a one time thing.

Good to know!

I don't understand the relation to recursive mini buffers.

Doesn't matter too much, since marking eglot-server-programs as safe to override doesn't lead to any issues. I mostly brought it up in case you've seen the error before and had some fix for it.

I would follow @nemethf advice and try to use workspaceComfiguration instead of this technique.

Will do, thanks again for your help!

[nemethf]

Since rust-analyzer can only be configured via initializationOptions,

This is generally not true. Last time I looked, intializaionOptions was only necessary to set the location of the rustfmt executable. See #845

[rbartlensky]

The manual seems to suggest that most config values are passed via initializationOptions.

[ia0]

@rbartlensky you might be interested by the "Experimental setup" section of #1214. This is my solution for per project initialization options. It might not be exactly what you want because I'm only interested in dynamically changing the options. In particular I don't persist them, which means that restarting emacs would lose any configuration. Maybe I'll add such feature if I need it, but so far I'm fine doing C-c c and updating the cargo invocation each time I need it.