Passing extra formatting options to LSPs (#2635)

* allows passing extra formatting options to LSPs

- adds optional field 'format' to [[language]] sections in 'languages.toml'

- passes specified options the LSPs via FormattingOptions

* cleaner conversion of formatting properties

* move formatting options inside lsp::Client

* cleans up formatting properties merge

1 files changed, 20 insertions, 0 deletions

diff --git a/helix-lsp/src/client.rs b/helix-lsp/src/client.rs
index 08201b3f..7f556ca6 100644
--- a/helix-lsp/src/client.rs
+++ b/helix-lsp/src/client.rs
@@ -7,7 +7,9 @@ use anyhow::anyhow;
 use helix_core::{find_root, ChangeSet, Rope};
 use jsonrpc_core as jsonrpc;
 use lsp_types as lsp;
+use serde::Deserialize;
 use serde_json::Value;
+use std::collections::HashMap;
 use std::future::Future;
 use std::process::Stdio;
 use std::sync::{
@@ -693,6 +695,24 @@ impl Client {
         };
         // TODO: return err::unavailable so we can fall back to tree sitter formatting
 
+        // merge FormattingOptions with 'config.format'
+        let config_format = self
+            .config
+            .as_ref()
+            .and_then(|cfg| cfg.get("format"))
+            .and_then(|fmt| HashMap::<String, lsp::FormattingProperty>::deserialize(fmt).ok());
+
+        let options = if let Some(mut properties) = config_format {
+            // passed in options take precedence over 'config.format'
+            properties.extend(options.properties);
+            lsp::FormattingOptions {
+                properties,
+                ..options
+            }
+        } else {
+            options
+        };
+
         let params = lsp::DocumentFormattingParams {
             text_document,
             options,