From 71551d395b4e47804df2d8ecea99e34dbbf16157 Mon Sep 17 00:00:00 2001
From: Philipp Mildenberger
Date: Mon, 23 May 2022 18:10:48 +0200
Subject: Adds support for multiple language servers per language.

Language Servers are now configured in a separate table in `languages.toml`:

```toml
[langauge-server.mylang-lsp]
command = "mylang-lsp"
args = ["--stdio"]
config = { provideFormatter = true }

[language-server.efm-lsp-prettier]
command = "efm-langserver"

[language-server.efm-lsp-prettier.config]
documentFormatting = true
languages = { typescript = [ { formatCommand ="prettier --stdin-filepath ${INPUT}", formatStdin = true } ] }
```

The language server for a language is configured like this (`typescript-language-server` is configured by default):

```toml
[[language]]
name = "typescript"
language-servers = [ { name = "efm-lsp-prettier", only-features = [ "format" ] }, "typescript-language-server" ]
```

or equivalent:

```toml
[[language]]
name = "typescript"
language-servers = [ { name = "typescript-language-server", except-features = [ "format" ] }, "efm-lsp-prettier" ]
```

Each requested LSP feature is priorized in the order of the `language-servers` array.
For example the first `goto-definition` supported language server (in this case `typescript-language-server`) will be taken for the relevant LSP request (command `goto_definition`).

If no `except-features` or `only-features` is given all features for the language server are enabled, as long as the language server supports these. If it doesn't the next language server which supports the feature is tried.

The list of supported features are:

- `format`
- `goto-definition`
- `goto-declaration`
- `goto-type-definition`
- `goto-reference`
- `goto-implementation`
- `signature-help`
- `hover`
- `document-highlight`
- `completion`
- `code-action`
- `workspace-command`
- `document-symbols`
- `workspace-symbols`
- `diagnostics`
- `rename-symbol`
- `inlay-hints`

Another side-effect/difference that comes with this PR, is that only one language server instance is started if different languages use the same language server.
---
 helix-core/src/diagnostic.rs | 1 +
 1 file changed, 1 insertion(+)

(limited to 'helix-core/src/diagnostic.rs')

diff --git a/helix-core/src/diagnostic.rs b/helix-core/src/diagnostic.rs
index 58ddb038..0b75d2a5 100644
--- a/helix-core/src/diagnostic.rs
+++ b/helix-core/src/diagnostic.rs
@@ -43,6 +43,7 @@ pub struct Diagnostic {
     pub message: String,
     pub severity: Option<Severity>,
     pub code: Option<NumberOrString>,
+    pub language_server_id: usize,
     pub tags: Vec<DiagnosticTag>,
     pub source: Option<String>,
     pub data: Option<serde_json::Value>,
-- 
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