Improve unknown file type handling in language server (#1455)

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.serviceRegistry.hasServices(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(() => {

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

@@ -640,12 +640,12 @@ export function createHierarchyRequestHandler<P extends TypeHierarchySupertypesP
         if (cancellationError) {
             return cancellationError;
         }
-        const language = serviceRegistry.getServices(uri);
-        if (!language) {
-            const message = `Could not find service instance for uri: '${uri.toString()}'`;
-            console.error(message);
-            throw new Error(message);
+        if (!serviceRegistry.hasServices(uri)) {
+            const errorText = `Could not find service instance for uri: '${uri}'`;
+            console.debug(errorText);
+            return responseError<E>(new Error(errorText));
         }
+        const language = serviceRegistry.getServices(uri);
         try {
             return await serviceCall(language, params, cancelToken);
         } catch (err) {
@@ -667,14 +667,14 @@ export function createServerRequestHandler<P extends { textDocument: TextDocumen
         if (cancellationError) {
             return cancellationError;
         }
-        const language = serviceRegistry.getServices(uri);
-        if (!language) {
+        if (!serviceRegistry.hasServices(uri)) {
             const errorText = `Could not find service instance for uri: '${uri}'`;
-            console.error(errorText);
-            throw new Error(errorText);
+            console.debug(errorText);
+            return responseError<E>(new Error(errorText));
         }
-        const document = await documents.getOrCreateDocument(uri);
+        const language = serviceRegistry.getServices(uri);
         try {
+            const document = await documents.getOrCreateDocument(uri);
             return await serviceCall(language, document, params, cancelToken);
         } catch (err) {
             return responseError<E>(err);
@@ -695,16 +695,13 @@ export function createRequestHandler<P extends { textDocument: TextDocumentIdent
         if (cancellationError) {
             return cancellationError;
         }
-        const language = serviceRegistry.getServices(uri);
-        if (!language) {
-            console.error(`Could not find service instance for uri: '${uri.toString()}'`);
-            return null;
-        }
-        const document = documents.getDocument(uri);
-        if (!document) {
+        if (!serviceRegistry.hasServices(uri)) {
+            console.debug(`Could not find service instance for uri: '${uri.toString()}'`);
             return null;
         }
+        const language = serviceRegistry.getServices(uri);
         try {
+            const document = await documents.getOrCreateDocument(uri);
             return await serviceCall(language, document, params, cancelToken);
         } catch (err) {
             return responseError<E>(err);

packages/langium/src/service-registry.ts

@@ -24,6 +24,11 @@ export interface ServiceRegistry {
      */
     getServices(uri: URI): LangiumCoreServices;
 
+    /**
+     * Check whether services are available for the given URI.
+     */
+    hasServices(uri: URI): boolean;
+
     /**
      * The full set of registered language services.
      */
@@ -78,6 +83,15 @@ export class DefaultServiceRegistry implements ServiceRegistry {
         return services;
     }
 
+    hasServices(uri: URI): boolean {
+        try {
+            this.getServices(uri);
+            return true;
+        } catch {
+            return false;
+        }
+    }
+
     get all(): readonly LangiumCoreServices[] {
         if (this.singleton !== undefined) {
             return [this.singleton];