Problem parsing emacs initializing request

[samanpa]

RLS seems to be having issues converting the initializing message lsp_types::InitializeParams that it gets from my emacs installation.

The error it gets is Error("invalid type: null, expected a boolean", line: 0, column: 0).

Please find the gist below that contains the reproducer.
https://gist.github.com/samanpa/7bb31219b53e803e11cee26de8de7b1a

The error goes away when lsp-types is compiled without the proposed feature.

Problematic toml

[dependencies]
lsp-types = { version = "0.70", features = ["proposed"] }
serde = {version = "1.0", features = [ "derive" ]}
serde_json = "1.0"

Working toml

[dependencies]
lsp-types = { version = "0.70" }
serde = {version = "1.0", features = [ "derive" ]}
serde_json = "1.0"

[samanpa]

Manually setting

"semanticHighlighting": null   

to true also fixes the issue. I guess it is more of a serde_json issue.

[matklad]

I think that was a bug in lsp-mode, which was fixed a while ago.

[samanpa]

I have a smaller reproducer

use serde::{Deserialize, Serialize};

fn main() -> std::result::Result<(), Box<dyn std::error::Error>> {
    let value = serde_json::json!{
        {
            "semanticHighlightingCapabilities": {
                     "semanticHighlighting": null
                 }
        }
    };
    let res : TextDocumentClientCapabilities = serde_json::from_value(value)?;
    Ok(())
}

#[derive(Debug,  Deserialize, Serialize)]
#[serde(rename_all = "camelCase")]
pub struct TextDocumentClientCapabilities {
    pub semantic_highlighting_capabilities: Option<SemanticHighlightingClientCapability>,
}

#[derive(Default, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct SemanticHighlightingClientCapability {
    pub semantic_highlighting: bool,
}

Is serde_json not working correctly.

[samanpa]

Never mind. It is an emacs bug.

[mvaled]

@samanpa

Could you point us to the Emacs bug? I've updated my Emacs configuration and I'm getting a similar error while lsp-mode tries to run rust-analyzer.

[mvaled]

To answer my own question. lsp-mode.el is passing elisp's nil as null the variable in question is 'lsp-enable-semantic-highlighting'; but in Rust bool doesn't accept null values.

I worked around the issue by setting the variable to t.

[flodiebold]

@mvaled That bug has been fixed since 4 months in lsp-mode, so I'd recommend updating.

[samanpa]

Last I checked the change is not in melpa stable.

[mvaled]

I updated yesterday and now there's no variable lsp-enable-semantic-highlighting.

[matklad]

I think the new semantic tokens protocol is not yet supported in Emacs: emacs-lsp/lsp-mode#1482

…

On Mon, 11 May 2020 at 18:36, Manuel Vázquez Acosta < ***@***.***> wrote: Well I updated yesterday and now there's no variable lsp-enable-semantic-highlighting. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#3123 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AANB3M4N2QHASGZV6ZBTYTDRRASQZANCNFSM4KT4MO2A> .

[flodiebold]

There's some support for some kind of semantic highlighting, but I'm not sure how well it works and whether it implements the current proposal (I guess I should try it out sometime). The variable got renamed to lsp-semantic-highlighting, I think.

[mvaled]

Yep. I can find lsp-semantic-highlighting which is nil by default...

I haven't read about semantic highlighting yet. I'll read about it later.