refactor(language_server): do not request for worspace configuration when the client does not support it (#10507)

Sysix · Sysix · commit db05a1522b8a · 2025-04-21T18:12:14.000Z
Currently working on supporting multiple workspace folder. `workspace/didChangeConfiguratoin` does not specific the Workspace, so some clients expect to request them.
We need to check if the client support this or fallback to a global configuration change (changing all workspaces).

ChatGPT:

&gt; what if workspace/configuration is not supported by the clinet
ChatGPT:
 Ah, good follow-up &mdash; if the client does not support workspace/configuration, things get more limited and require some careful handling.
&#128295; First: Check If the Client Supports It
When your language server receives the initialize request from the client, it includes its capabilities. Look for:
```
"capabilities": {
  "workspace": {
    "configuration": true
  }
}
```
&gt; If that configuration field is false or missing, then you cannot use workspace/configuration, and the client will only send global settings via workspace/didChangeConfiguration.
diff --git a/crates/oxc_language_server/src/capabilities.rs b/crates/oxc_language_server/src/capabilities.rs
@@ -7,11 +7,12 @@ use tower_lsp_server::lsp_types::{
 
 use crate::{code_actions::CODE_ACTION_KIND_SOURCE_FIX_ALL_OXC, commands::LSP_COMMANDS};
 
-#[derive(Clone)]
+#[derive(Clone, Default)]
 pub struct Capabilities {
     pub code_action_provider: bool,
     pub workspace_apply_edit: bool,
     pub workspace_execute_command: bool,
+    pub workspace_configuration: bool,
 }
 
 impl From<ClientCapabilities> for Capabilities {
@@ -28,8 +29,17 @@ impl From<ClientCapabilities> for Capabilities {
             value.workspace.as_ref().is_some_and(|workspace| workspace.apply_edit.is_some());
         let workspace_execute_command =
             value.workspace.as_ref().is_some_and(|workspace| workspace.execute_command.is_some());
+        let workspace_configuration = value
+            .workspace
+            .as_ref()
+            .is_some_and(|workspace| workspace.configuration.is_some_and(|config| config));
 
-        Self { code_action_provider, workspace_apply_edit, workspace_execute_command }
+        Self {
+            code_action_provider,
+            workspace_apply_edit,
+            workspace_execute_command,
+            workspace_configuration,
+        }
     }
 }
 
diff --git a/crates/oxc_language_server/src/main.rs b/crates/oxc_language_server/src/main.rs
@@ -45,6 +45,7 @@ const OXC_CONFIG_FILE: &str = ".oxlintrc.json";
 struct Backend {
     client: Client,
     root_uri: OnceCell<Option<Uri>>,
+    capabilities: OnceCell<Capabilities>,
     server_linter: RwLock<ServerLinter>,
     diagnostics_report_map: ConcurrentHashMap<String, Vec<DiagnosticReport>>,
     options: Mutex<Options>,
@@ -102,21 +103,37 @@ impl LanguageServer for Backend {
             *self.options.lock().await = value;
         }
 
+        let capabilities = Capabilities::from(params.capabilities);
+        self.capabilities.set(capabilities.clone()).map_err(|err| {
+            let message = match err {
+                SetError::AlreadyInitializedError(_) => {
+                    "capabilities are already initialized".into()
+                }
+                SetError::InitializingError(_) => "initializing error".into(),
+            };
+
+            Error { code: ErrorCode::ParseError, message, data: None }
+        })?;
+
         self.init_nested_configs().await;
         let oxlintrc = self.init_linter_config().await;
         self.init_ignore_glob(oxlintrc).await;
         Ok(InitializeResult {
             server_info: Some(ServerInfo { name: "oxc".into(), version: None }),
             offset_encoding: None,
-            capabilities: Capabilities::from(params.capabilities).into(),
+            capabilities: capabilities.into(),
         })
     }
 
     async fn did_change_configuration(&self, params: DidChangeConfigurationParams) {
         let changed_options =
             if let Ok(options) = serde_json::from_value::<Options>(params.settings) {
                 options
-            } else {
+            } else if self
+                .capabilities
+                .get()
+                .is_some_and(|capabilities| capabilities.workspace_configuration)
+            {
                 // Fallback if some client didn't took changed configuration in params of `workspace/configuration`
                 let Some(options) = self
                     .client
@@ -133,6 +150,10 @@ impl LanguageServer for Backend {
                     return;
                 };
                 options
+            } else {
+                // the client did not give os changes to the configuration and he is not able to respond to `workspace/configuration`
+                // so we fallback to the current configuration
+                self.options.lock().await.clone()
             };
 
         let current_option = &self.options.lock().await.clone();
@@ -565,6 +586,7 @@ async fn main() {
     let (service, socket) = LspService::build(|client| Backend {
         client,
         root_uri: OnceCell::new(),
+        capabilities: OnceCell::new(),
         server_linter: RwLock::new(server_linter),
         diagnostics_report_map,
         options: Mutex::new(Options::default()),
