Situational LSP on same file extension

[ngasull]

Intro

Some languages have multiple possible language servers, in my case the (in)famous Javascript/Typescript:

• typescript-language-server
• deno lsp
• even eslint, tailwindcss or any other situational language support, all for the same file types (jsx?/tsx?)

Formal issue

Language support may depend on configured tooling in the workspace rather than just file extension. roots isn't requiring the existence of the files.

Possible enhancements

1. Adding a language.toml flag key to actually require one of the roots files to be found to in order to enable the LSP
   Eg. require-root = true
2. Adding a language.toml configuration key of possible marker files in found root that enables the LSP.
   Eg. required-roots = ["deno.json", "deno.jsonc", "deno.lock"]

Option 1 seems relevant and sufficient to cover multiple LSP per file type while keeping things simple.

Current workaround

Dropping an .helix/languages.toml situationally in workspaces.

[ontley]

I want to work on this, but I don't really know where this would check be performed? Registry::get maybe?

[pascalkuthe]

yeah registry::get is mostly the right place.

I don't think the option should be to only start if roots exists but a bit more general: to only start if the detected lsp root directory (there is always one even if none of the root markers are found) contains files matching any of a list of globs (use globset since we already depend on it).

That way you could also check for a different file here and copying the root markers isn't too hard.

The best way to implement this is probably to make start_client return an Result<Option<T>> (None corresponds to no marker found and you can simply use the ? with filter_map to filter those kinds of servers

[ontley]

Makes sense, I'll see what I can do.

Unfortunately I'm away until next thursday.

[ontley]

the detected lsp root directory (there is always one even if none of the root markers are found)

Does this refer to Config.workspace_lsp_roots / the root_dirs argument in start_client? They seem to be empty even after :lsp-restart

[ontley]

Nvm, I realized I need root_path from Client::start