Allow extensions to define more of the methods in the LspAdapter trait (#9554)

Our goal is to extract Svelte support into an extension, since we've
seen problems with the Tree-sitter Svelte parser crashing due to bugs in
the external scanner. In order to do this, we need a couple more
capabilities in LSP extensions:

* [x] `initialization_options` - programmatically controlling the JSON
initialization params sent to the language server
* [x] `prettier_plugins` - statically specifying a list of prettier
plugins that apply for a given language.
* [x] `npm_install_package`

Release Notes:

- N/A

---------

Co-authored-by: Marshall <marshall@zed.dev>
Co-authored-by: Marshall Bowers <elliott.codes@gmail.com>

crates/language/src/language.rs

@@ -259,10 +259,6 @@ impl CachedLspAdapter {
         self.adapter.label_for_symbol(name, kind, language).await
     }
 
-    pub fn prettier_plugins(&self) -> &[&'static str] {
-        self.adapter.prettier_plugins()
-    }
-
     #[cfg(any(test, feature = "test-support"))]
     fn as_fake(&self) -> Option<&FakeLspAdapter> {
         self.adapter.as_fake()
@@ -441,8 +437,11 @@ pub trait LspAdapter: 'static + Send + Sync {
     }
 
     /// Returns initialization options that are going to be sent to a LSP server as a part of [`lsp::InitializeParams`]
-    fn initialization_options(&self) -> Option<Value> {
-        None
+    async fn initialization_options(
+        self: Arc<Self>,
+        _: &Arc<dyn LspAdapterDelegate>,
+    ) -> Result<Option<Value>> {
+        Ok(None)
     }
 
     fn workspace_configuration(&self, _workspace_root: &Path, _cx: &mut AppContext) -> Value {
@@ -472,10 +471,6 @@ pub trait LspAdapter: 'static + Send + Sync {
         Default::default()
     }
 
-    fn prettier_plugins(&self) -> &[&'static str] {
-        &[]
-    }
-
     #[cfg(any(test, feature = "test-support"))]
     fn as_fake(&self) -> Option<&FakeLspAdapter> {
         None
@@ -575,6 +570,9 @@ pub struct LanguageConfig {
     /// The name of a Prettier parser that should be used for this language.
     #[serde(default)]
     pub prettier_parser_name: Option<String>,
+    /// The names of any Prettier plugins that should be used for this language.
+    #[serde(default)]
+    pub prettier_plugins: Vec<Arc<str>>,
 }
 
 #[derive(Clone, Debug, Serialize, Deserialize, Default, JsonSchema)]
@@ -656,6 +654,7 @@ impl Default for LanguageConfig {
             overrides: Default::default(),
             word_characters: Default::default(),
             prettier_parser_name: None,
+            prettier_plugins: Default::default(),
             collapsed_placeholder: Default::default(),
         }
     }
@@ -1283,6 +1282,10 @@ impl Language {
     pub fn prettier_parser_name(&self) -> Option<&str> {
         self.config.prettier_parser_name.as_deref()
     }
+
+    pub fn prettier_plugins(&self) -> &Vec<Arc<str>> {
+        &self.config.prettier_plugins
+    }
 }
 
 impl LanguageScope {
@@ -1547,12 +1550,11 @@ impl LspAdapter for FakeLspAdapter {
         self.disk_based_diagnostics_progress_token.clone()
     }
 
-    fn initialization_options(&self) -> Option<Value> {
-        self.initialization_options.clone()
-    }
-
-    fn prettier_plugins(&self) -> &[&'static str] {
-        &self.prettier_plugins
+    async fn initialization_options(
+        self: Arc<Self>,
+        _: &Arc<dyn LspAdapterDelegate>,
+    ) -> Result<Option<Value>> {
+        Ok(self.initialization_options.clone())
     }
 
     fn as_fake(&self) -> Option<&FakeLspAdapter> {

crates/language/src/language_registry.rs

@@ -63,7 +63,7 @@ pub enum LanguageServerBinaryStatus {
 
 pub struct PendingLanguageServer {
     pub server_id: LanguageServerId,
-    pub task: Task<Result<lsp::LanguageServer>>,
+    pub task: Task<Result<(lsp::LanguageServer, Option<serde_json::Value>)>>,
     pub container_dir: Option<Arc<Path>>,
 }
 
@@ -629,6 +629,15 @@ impl LanguageRegistry {
             .unwrap_or_default()
     }
 
+    pub fn all_prettier_plugins(&self) -> Vec<Arc<str>> {
+        let state = self.state.read();
+        state
+            .languages
+            .iter()
+            .flat_map(|language| language.config.prettier_plugins.iter().cloned())
+            .collect()
+    }
+
     pub fn update_lsp_status(
         &self,
         server_name: LanguageServerName,
@@ -680,6 +689,12 @@ impl LanguageRegistry {
                     )
                     .await?;
 
+                let options = adapter
+                    .adapter
+                    .clone()
+                    .initialization_options(&delegate)
+                    .await?;
+
                 if let Some(task) = adapter.will_start_server(&delegate, &mut cx) {
                     task.await?;
                 }
@@ -727,18 +742,21 @@ impl LanguageRegistry {
                         })
                         .detach();
 
-                    return Ok(server);
+                    return Ok((server, options));
                 }
 
                 drop(this);
-                lsp::LanguageServer::new(
-                    stderr_capture,
-                    server_id,
-                    binary,
-                    &root_path,
-                    adapter.code_action_kinds(),
-                    cx,
-                )
+                Ok((
+                    lsp::LanguageServer::new(
+                        stderr_capture,
+                        server_id,
+                        binary,
+                        &root_path,
+                        adapter.code_action_kinds(),
+                        cx,
+                    )?,
+                    options,
+                ))
             }
         });