refactor(language_server/editor): refresh file watchers without restarting the server (didChangeConfiguration) (oxc-project#11112)

Author: Sysix

crates/oxc_language_server/README.md

@@ -52,7 +52,8 @@ The client can pass the workspace options like following:
 
 ### [initialized](https://microsoft.github.io/language-server-protocol/specification#initialized)
 
-When the client did not pass the workspace configuration in [initialize](#initialize), the server will request the configuration for every workspace with [workspace/configuration](#workspace/configuration).
+When the client did not pass the workspace configuration in [initialize](#initialize), the server will request the configuration for every workspace with [workspace/configuration](#workspaceconfiguration).
+The server will tell the client with [client/registerCapability](#clientregistercapability) to watch for `.oxlintrc.json` files or a custom `oxc.configPath`.
 
 ### [shutdown](https://microsoft.github.io/language-server-protocol/specification#shutdown)
 
@@ -80,6 +81,10 @@ The client can pass the workspace options like following:
 When the client does not pass workspace options, the server will request them with [workspace/configuration](#workspace/configuration).
 The server will revalidate or reset the diagnostics for all open files and send one or more [textDocument/publishDiagnostics](#textdocumentpublishdiagnostics) requests to the client.
 
+When changing the `oxc.configPath` settings:
+The server will tell clients with [client/registerCapability](#clientregistercapability) to watch for `.oxlintrc.json` files or a custom `oxc.configPath`.
+The server will tell clients with [client/unregisterCapability](#clientunregistercapability) to stop watching for `.oxlintrc.json` files or a custom `oxc.configPath`.
+
 #### [workspace/didChangeWatchedFiles](https://microsoft.github.io/language-server-protocol/specification#workspace_didChangeWatchedFiles)
 
 The server expects this request when one oxlint configuration is changed, added or deleted.
@@ -91,6 +96,8 @@ Note: When nested configuration is active, the client should send all `.oxlintrc
 
 The server expects this request when adding or removing workspace folders.
 The server will request the specific workspace configuration, if the client supports it.
+The server will tell clients with [client/registerCapability](#clientregistercapability) to watch for `.oxlintrc.json` files or a custom `oxc.configPath`.
+The server will tell clients with [client/unregisterCapability](#clientunregistercapability) to stop watching for `.oxlintrc.json` files or a custom `oxc.configPath`.
 
 #### [workspace/executeCommand](https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#workspace_executeCommand)
 
@@ -126,7 +133,17 @@ Returns a list of [CodeAction](https://microsoft.github.io/language-server-proto
 
 Returns a [PublishDiagnostic object](https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#publishDiagnosticsParams)
 
-# Optional LSP Specifications from Client
+## Optional LSP Specifications from Client
+
+### Client
+
+#### [client/registerCapability](https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#client_registerCapability)
+
+The server will send this request to watch for specific files. The method `workspace/didChangeWatchedFiles` will be used with custom `registerOptions`.
+
+#### [client/unregisterCapability](https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#client_unregisterCapability)
+
+The server will send this request to stop watching for specific files. The `id` will match from [client/registerCapability](#clientregistercapability).
 
 ### Workspace
 

crates/oxc_language_server/src/main.rs

@@ -203,6 +203,8 @@ impl LanguageServer for Backend {
         let workers = self.workspace_workers.lock().await;
         let new_diagnostics: papaya::HashMap<String, Vec<Diagnostic>, FxBuildHasher> =
             ConcurrentHashMap::default();
+        let mut removing_registrations = vec![];
+        let mut adding_registrations = vec![];
 
         // new valid configuration is passed
         let options = serde_json::from_value::<Vec<WorkspaceOption>>(params.settings.clone())
@@ -233,16 +235,31 @@ impl LanguageServer for Backend {
                     continue;
                 };
 
-                let Some(diagnostics) = worker.did_change_configuration(&option.options).await
-                else {
-                    continue;
-                };
+                let (diagnostics, watcher) = worker.did_change_configuration(&option.options).await;
 
-                for (uri, reports) in &diagnostics.pin() {
-                    new_diagnostics.pin().insert(
-                        uri.clone(),
-                        reports.iter().map(|d| d.diagnostic.clone()).collect(),
-                    );
+                if let Some(diagnostics) = diagnostics {
+                    for (uri, reports) in &diagnostics.pin() {
+                        new_diagnostics.pin().insert(
+                            uri.clone(),
+                            reports.iter().map(|d| d.diagnostic.clone()).collect(),
+                        );
+                    }
+                }
+
+                if let Some(watcher) = watcher {
+                    // remove the old watcher
+                    removing_registrations.push(Unregistration {
+                        id: format!("watcher-{}", worker.get_root_uri().as_str()),
+                        method: "workspace/didChangeWatchedFiles".to_string(),
+                    });
+                    // add the new watcher
+                    adding_registrations.push(Registration {
+                        id: format!("watcher-{}", worker.get_root_uri().as_str()),
+                        method: "workspace/didChangeWatchedFiles".to_string(),
+                        register_options: Some(json!(DidChangeWatchedFilesRegistrationOptions {
+                            watchers: vec![watcher]
+                        })),
+                    });
                 }
             }
         // else check if the client support workspace configuration requests
@@ -263,15 +280,32 @@ impl LanguageServer for Backend {
                 let Some(config) = &configs[index] else {
                     continue;
                 };
-                let Some(diagnostics) = worker.did_change_configuration(config).await else {
-                    continue;
-                };
 
-                for (uri, reports) in &diagnostics.pin() {
-                    new_diagnostics.pin().insert(
-                        uri.clone(),
-                        reports.iter().map(|d| d.diagnostic.clone()).collect(),
-                    );
+                let (diagnostics, watcher) = worker.did_change_configuration(config).await;
+
+                if let Some(diagnostics) = diagnostics {
+                    for (uri, reports) in &diagnostics.pin() {
+                        new_diagnostics.pin().insert(
+                            uri.clone(),
+                            reports.iter().map(|d| d.diagnostic.clone()).collect(),
+                        );
+                    }
+                }
+
+                if let Some(watcher) = watcher {
+                    // remove the old watcher
+                    removing_registrations.push(Unregistration {
+                        id: format!("watcher-{}", worker.get_root_uri().as_str()),
+                        method: "workspace/didChangeWatchedFiles".to_string(),
+                    });
+                    // add the new watcher
+                    adding_registrations.push(Registration {
+                        id: format!("watcher-{}", worker.get_root_uri().as_str()),
+                        method: "workspace/didChangeWatchedFiles".to_string(),
+                        register_options: Some(json!(DidChangeWatchedFilesRegistrationOptions {
+                            watchers: vec![watcher]
+                        })),
+                    });
                 }
             }
         } else {
@@ -281,17 +315,28 @@ impl LanguageServer for Backend {
             return;
         }
 
-        if new_diagnostics.is_empty() {
-            return;
-        }
+        if !new_diagnostics.is_empty() {
+            let x = &new_diagnostics
+                .pin()
+                .into_iter()
+                .map(|(key, value)| (key.clone(), value.clone()))
+                .collect::<Vec<_>>();
 
-        let x = &new_diagnostics
-            .pin()
-            .into_iter()
-            .map(|(key, value)| (key.clone(), value.clone()))
-            .collect::<Vec<_>>();
+            self.publish_all_diagnostics(x).await;
+        }
 
-        self.publish_all_diagnostics(x).await;
+        if self.capabilities.get().is_some_and(|capabilities| capabilities.dynamic_watchers) {
+            if !removing_registrations.is_empty() {
+                if let Err(err) = self.client.unregister_capability(removing_registrations).await {
+                    warn!("sending unregisterCapability.didChangeWatchedFiles failed: {err}");
+                }
+            }
+            if !adding_registrations.is_empty() {
+                if let Err(err) = self.client.register_capability(adding_registrations).await {
+                    warn!("sending registerCapability.didChangeWatchedFiles failed: {err}");
+                }
+            }
+        }
     }
 
     async fn did_change_watched_files(&self, params: DidChangeWatchedFilesParams) {

crates/oxc_language_server/src/worker.rs

@@ -246,7 +246,7 @@ impl WorkspaceWorker {
     pub async fn did_change_configuration(
         &self,
         changed_options: &Options,
-    ) -> Option<ConcurrentHashMap<String, Vec<DiagnosticReport>>> {
+    ) -> (Option<ConcurrentHashMap<String, Vec<DiagnosticReport>>>, Option<FileSystemWatcher>) {
         let current_option = &self.options.lock().await.clone();
 
         debug!(
@@ -261,10 +261,28 @@ impl WorkspaceWorker {
 
         if Self::needs_linter_restart(current_option, changed_options) {
             self.refresh_server_linter().await;
-            return Some(self.revalidate_diagnostics().await);
+
+            if current_option.config_path != changed_options.config_path {
+                return (
+                    Some(self.revalidate_diagnostics().await),
+                    Some(FileSystemWatcher {
+                        glob_pattern: GlobPattern::Relative(RelativePattern {
+                            base_uri: OneOf::Right(self.root_uri.clone()),
+                            pattern: changed_options
+                                .config_path
+                                .as_ref()
+                                .unwrap_or(&"**/.oxlintrc.json".to_string())
+                                .to_owned(),
+                        }),
+                        kind: Some(WatchKind::all()), // created, deleted, changed
+                    }),
+                );
+            }
+
+            return (Some(self.revalidate_diagnostics().await), None);
         }
 
-        None
+        (None, None)
     }
 }
 

editors/vscode/client/ConfigService.ts

@@ -59,15 +59,6 @@ export class ConfigService implements IDisposable {
     return false;
   }
 
-  public effectsWorkspaceConfigPathChange(event: ConfigurationChangeEvent): boolean {
-    for (const workspaceConfig of this.workspaceConfigs.values()) {
-      if (workspaceConfig.effectsConfigPathChange(event)) {
-        return true;
-      }
-    }
-    return false;
-  }
-
   private async onVscodeConfigChange(event: ConfigurationChangeEvent): Promise<void> {
     let isConfigChanged = false;
 

editors/vscode/client/WorkspaceConfig.ts

@@ -69,10 +69,6 @@ export class WorkspaceConfig {
     return false;
   }
 
-  public effectsConfigPathChange(event: ConfigurationChangeEvent): boolean {
-    return event.affectsConfiguration(`${ConfigService.namespace}.configPath`, this.workspace);
-  }
-
   public get isCustomConfigPath(): boolean {
     return this.configPath !== null && this.configPath !== oxlintConfigFileName;
   }

editors/vscode/client/extension.ts

@@ -258,12 +258,7 @@ export async function activate(context: ExtensionContext) {
     // update the initializationOptions for a possible restart
     client.clientOptions.initializationOptions = this.languageServerConfig;
 
-    if (configService.effectsWorkspaceConfigPathChange(event)) {
-      // Server does not support currently adding/removing watchers on the fly
-      if (client.isRunning()) {
-        await client.restart();
-      }
-    } else if (configService.effectsWorkspaceConfigChange(event) && client.isRunning()) {
+    if (configService.effectsWorkspaceConfigChange(event) && client.isRunning()) {
       await client.sendNotification(
         'workspace/didChangeConfiguration',
         {