Improve unknown file type handling in language server

packages/langium/src/lsp/document-update-handler.ts

@@ -12,6 +12,7 @@ import type { TextDocument } from '../workspace/documents.js';
 import type { WorkspaceLock } from '../workspace/workspace-lock.js';
 import type { LangiumSharedServices } from './lsp-services.js';
 import type { WorkspaceManager } from '../workspace/workspace-manager.js';
+import type { ServiceRegistry } from '../service-registry.js';
 
 /**
  * Shared service for handling text document changes and watching relevant files.
@@ -35,11 +36,13 @@ export class DefaultDocumentUpdateHandler implements DocumentUpdateHandler {
     protected readonly workspaceManager: WorkspaceManager;
     protected readonly documentBuilder: DocumentBuilder;
     protected readonly workspaceLock: WorkspaceLock;
+    protected readonly serviceRegistry: ServiceRegistry;
 
     constructor(services: LangiumSharedServices) {
         this.workspaceManager = services.workspace.WorkspaceManager;
         this.documentBuilder = services.workspace.DocumentBuilder;
         this.workspaceLock = services.workspace.WorkspaceLock;
+        this.serviceRegistry = services.ServiceRegistry;
 
         let canRegisterFileWatcher = false;
         services.lsp.LanguageServer.onInitialize(params => {
@@ -73,6 +76,9 @@ export class DefaultDocumentUpdateHandler implements DocumentUpdateHandler {
     }
 
     protected fireDocumentUpdate(changed: URI[], deleted: URI[]): void {
+        // Filter out URIs that do not have a service in the registry
+        // Running the document builder update will fail for those URIs
+        changed = changed.filter(uri => this.hasService(uri));
         // Only fire the document update when the workspace manager is ready
         // Otherwise, we might miss the initial indexing of the workspace
         this.workspaceManager.ready.then(() => {
@@ -83,6 +89,23 @@ export class DefaultDocumentUpdateHandler implements DocumentUpdateHandler {
         });
     }
 
+    /**
+     * Check whether the service registry contains a service instance for the given URI.
+     *
+     * Some language clients (vscode) decide to send update notifications for files that have been renamed to a different file extension.
+     * In this case, the service registry may not contain a service for the new URI. We have to ignore any changes to those files.
+     *
+     * In case we only have a single language in our registry, we can safely use that language for all URIs.
+     */
+    protected hasService(uri: URI): boolean {
+        try {
+            this.serviceRegistry.getServices(uri);
+            return true;
+        } catch {
+            return false;
+        }
+    }
+
     didChangeContent(change: TextDocumentChangeEvent<TextDocument>): void {
         this.fireDocumentUpdate([URI.parse(change.document.uri)], []);
     }

packages/langium/src/lsp/index.ts

@@ -15,7 +15,9 @@ export * from './default-lsp-module.js';
 export * from './document-highlight-provider.js';
 export * from './document-link-provider.js';
 export * from './document-symbol-provider.js';
+export * from './document-update-handler.js';
 export * from './execute-command-handler.js';
+export * from './file-operation-handler.js';
 export * from './folding-range-provider.js';
 export * from './formatter.js';
 export * from './fuzzy-matcher.js';

packages/langium/src/lsp/language-server.ts

@@ -643,8 +643,8 @@ export function createHierarchyRequestHandler<P extends TypeHierarchySupertypesP
         const language = serviceRegistry.getServices(uri);
         if (!language) {
             const message = `Could not find service instance for uri: '${uri.toString()}'`;
-            console.error(message);
-            throw new Error(message);
+            console.debug(message);
+            return responseError<E>(new Error(message));
         }
         try {
             return await serviceCall(language, params, cancelToken);
@@ -667,11 +667,16 @@ export function createServerRequestHandler<P extends { textDocument: TextDocumen
         if (cancellationError) {
             return cancellationError;
         }
-        const language = serviceRegistry.getServices(uri);
+        let language: LangiumCoreAndPartialLSPServices | undefined;
+        try {
+            language = serviceRegistry.getServices(uri);
+        } catch {
+            // NOOP
+        }
         if (!language) {
             const errorText = `Could not find service instance for uri: '${uri}'`;
-            console.error(errorText);
-            throw new Error(errorText);
+            console.debug(errorText);
+            return responseError<E>(new Error(errorText));
         }
         const document = await documents.getOrCreateDocument(uri);
         try {
@@ -695,9 +700,14 @@ export function createRequestHandler<P extends { textDocument: TextDocumentIdent
         if (cancellationError) {
             return cancellationError;
         }
-        const language = serviceRegistry.getServices(uri);
+        let language: LangiumCoreAndPartialLSPServices | undefined;
+        try {
+            language = serviceRegistry.getServices(uri);
+        } catch {
+            // NOOP
+        }
         if (!language) {
-            console.error(`Could not find service instance for uri: '${uri.toString()}'`);
+            console.debug(`Could not find service instance for uri: '${uri.toString()}'`);
             return null;
         }
         const document = documents.getDocument(uri);