feat(lsp): commands

[matoous]

This is work in progress PR that implements LSP commands. Usable for example for code actions and code lens.

Fixes: #1299
Related: #183

[archseer]

The problem you're seeing is because you're trying to move language_server into the async closure.

This should work:

Suggested change

	tokio::spawn(async move {
	language_server.command(command).await
	});
	let future = language_server.command(command);
	tokio::spawn(async move {
	future.await
	// TODO: log the result here
	});

[matoous]

Tried that before, this moves the lifetime issue to

error[E0621]: explicit lifetime required in the type of `cx`
    --> helix-term/src/commands.rs:3268:30
     |
3268 |                 let picker = Picker::new(
     |                              ^^^^^^^^^^^ lifetime `'static` required

[archseer]

Right, you're also reusing the language_server from outside the cx.callback, and the compiler can't know how long the callback will live for. So it expects language_server -> doc -> cx to live for static.

To avoid this you need to re-fetch the doc/language_server inside the callback, easiest way to do that is let (doc, _view) = current!(editor), the most correct would be to let doc_id = doc.id() before cx.callback, then re-fetch that exact ID in the closure

[matoous]

Thanks a lot for the help! Fixed now. I also extracted the command execution into separate function so it can be re-used so it can be re-used between commands, code actions, and possibly code lenses in the future.

[archseer]

There's a reason the method did not use generics: due to monomorphization it can lead to code bloat since the method is big. The way to fix this would be to rename the old function as reply_impl, then define a new reply function that uses generics and calls reply_impl.

See the example here under "inlining in practice" (under "fifth,") https://matklad.github.io/2021/07/09/inline-in-rust.html

[matoous]

Wow, didn't realize the implications, thanks a lot. I just reverted the changes for now. If it isn't good enough I can introduce reply and reply_impl.

[matoous]

@archseer sorry, forgot to run clippy, the lint issue should be fixed now.

[archseer]

Thanks for working on this!