Refactor language server startup

Avoid parallel vecs

Co-Authored-By: Max Brunsfeld <max@zed.dev>

crates/language/src/language.rs

@@ -782,13 +782,14 @@ impl LanguageRegistry {
         self.state.read().languages.iter().cloned().collect()
     }
 
-    pub fn start_language_servers(
+    pub fn start_language_server(
         self: &Arc<Self>,
         language: Arc<Language>,
+        adapter: Arc<CachedLspAdapter>,
         root_path: Arc<Path>,
         http_client: Arc<dyn HttpClient>,
         cx: &mut AppContext,
-    ) -> Vec<PendingLanguageServer> {
+    ) -> Option<PendingLanguageServer> {
         #[cfg(any(test, feature = "test-support"))]
         if language.fake_adapter.is_some() {
             let task = cx.spawn(|cx| async move {
@@ -819,22 +820,15 @@ impl LanguageRegistry {
             });
 
             let server_id = post_inc(&mut self.state.write().next_language_server_id);
-            return vec![PendingLanguageServer { server_id, task }];
+            return Some(PendingLanguageServer { server_id, task });
         }
 
         let download_dir = self
             .language_server_download_dir
             .clone()
             .ok_or_else(|| anyhow!("language server download directory has not been assigned"))
-            .log_err();
-        let download_dir = match download_dir {
-            Some(download_dir) => download_dir,
-            None => return Vec::new(),
-        };
+            .log_err()?;
 
-        let mut results = Vec::new();
-
-        for adapter in &language.adapters {
         let this = self.clone();
         let language = language.clone();
         let http_client = http_client.clone();
@@ -879,10 +873,7 @@ impl LanguageRegistry {
             Ok(server)
         });
 
-            results.push(PendingLanguageServer { server_id, task });
-        }
-
-        results
+        Some(PendingLanguageServer { server_id, task })
     }
 
     pub fn language_server_binary_statuses(

crates/project/src/project.rs

@@ -2137,17 +2137,23 @@ impl Project {
             return;
         }
 
-        let adapters = language.lsp_adapters();
-        let language_servers = self.languages.start_language_servers(
+        for adapter in language.lsp_adapters() {
+            let key = (worktree_id, adapter.name.clone());
+            if self.language_server_ids.contains_key(&key) {
+                continue;
+            }
+
+            let pending_server = match self.languages.start_language_server(
                 language.clone(),
+                adapter.clone(),
                 worktree_path.clone(),
                 self.client.http_client(),
                 cx,
-        );
-        debug_assert_eq!(adapters.len(), language_servers.len());
+            ) {
+                Some(pending_server) => pending_server,
+                None => continue,
+            };
 
-        for (adapter, pending_server) in adapters.into_iter().zip(language_servers.into_iter()) {
-            let key = (worktree_id, adapter.name.clone());
             let lsp = &cx.global::<Settings>().lsp.get(&adapter.name.0);
             let override_options = lsp.map(|s| s.initialization_options.clone()).flatten();
 
@@ -2160,8 +2166,8 @@ impl Project {
                 _ => {}
             }
 
-            if !self.language_server_ids.contains_key(&key) {
-                let adapter = self.setup_pending_language_server(
+            let server_id = pending_server.server_id;
+            let state = self.setup_pending_language_server(
                 initialization_options,
                 pending_server,
                 adapter.clone(),
@@ -2169,8 +2175,8 @@ impl Project {
                 key.clone(),
                 cx,
             );
-                self.language_server_ids.insert(key.clone(), adapter);
-            }
+            self.language_servers.insert(server_id, state);
+            self.language_server_ids.insert(key.clone(), server_id);
         }
     }
 
@@ -2182,12 +2188,10 @@ impl Project {
         language: Arc<Language>,
         key: (WorktreeId, LanguageServerName),
         cx: &mut ModelContext<Project>,
-    ) -> usize {
+    ) -> LanguageServerState {
         let server_id = pending_server.server_id;
         let languages = self.languages.clone();
 
-        self.language_servers.insert(
-            server_id,
         LanguageServerState::Starting(cx.spawn_weak(|this, mut cx| async move {
             let workspace_config = cx.update(|cx| languages.workspace_configuration(cx)).await;
             let language_server = pending_server.task.await.log_err()?;
@@ -2229,7 +2233,6 @@ impl Project {
                     move |params, mut cx| {
                         let languages = languages.clone();
                         async move {
-                                dbg!(&params.items);
                             let workspace_config =
                                 cx.update(|cx| languages.workspace_configuration(cx)).await;
                             Ok(params
@@ -2459,9 +2462,7 @@ impl Project {
                 cx.notify();
                 Some(language_server)
             })
-            })),
-        );
-        server_id
+        }))
     }
 
     // Returns a list of all of the worktrees which no longer have a language server and the root path