Handle window/showMessage and display it bellow status line

[ayoub-benali]

This feature is also hidden behind the display-messages setting which is used for displaying Progress.

I don't think it make sense to create separate setting for this feature as I don't expect a server to send both Progress and window/showMessage but I can add one if you prefer.

Metals relies on this notification for providing info about the build and is configured here.

Hopefully this will be useful for other language servers.

Here is an example (bottom left) for the message sent by Metals.

Fix #5524

[pascalkuthe]

LGTM!

It's nice that helix now covers this parts of the spec aswell

[the-mikedavis]

I think there should be separate config for showMessage and progressMessage: progress messages are too verbose and distracting IMO but messages sent through showMessage are usually more important and meant for the user to read.

rust-analyzer and erlang-ls are two servers in the wild that behave like this:

• rust-analyzer uses showMessage for things like saying that the config is invalid: https://github.com/rust-lang/rust-analyzer/blob/5306eb06cc2de0566ca789ee3863b78059ee2376/crates/rust-analyzer/src/bin/main.rs#L173-L183
• erlang-ls uses showMessage to say that the config file is missing and how to set one up: https://github.com/erlang-ls/erlang_ls/blob/1a66e8798bb2c33dc1fefa46f054760d8edb767d/apps/els_core/src/els_config.erl#L358-L373

Both use progress messages that are very verbose about internal indexing processes which I don't want to see.

We might also want to consider putting the showMessage contents into a Popup instead of using the statusline so that you have to explicitly clear the notification with C-c.

[ayoub-benali]

What should be the new setting name ?
Progress is already using a missleading name. should I introduce a breaking change and make progress be controlled with 'display-progress-message' while show message would use the current name ?

[the-mikedavis]

Yeah I think you're right about the names. Ideally we should avoid breaking changes but I think progress messages would be better as display-progress-messages and showMessage messages as display-messages.

[ayoub-benali]

@the-mikedavis So I made the change but I think now a R-breaking-change label should be added to the PR, I couldn't do it myself.

[ayoub-benali]

@the-mikedavis Is the popup support a must have for this PR or could we added it later depending on the user requests ?
I think statusline is already better than nothing, since this LSP notification isn't even supported now

[igor-ramazanov]

Can we include this into the next release?

[AlexanderBrevig]

(sorry, I thought I was in another PR - still, I really do want this :) would make it a bit easier to use Helix as a client for testing new LSPs 👍🏻)

[the-mikedavis]

This totally fell of my radar for a while - sorry about that! Looking at the most recent changes I think this looks good. We could experiment with a popup separately but I think the statusline is good for now. I've merged master and also added a commit to enable this config option by default. false seems like the right default to me for progress messages but I think language servers are not usually so verbose that this new option needs to be false too.