Expose null progress reporter detection (#1827)

* Expose null progress reporter detection

* Address progress reporter API review

---------

Co-authored-by: Dirk Bäumer <dirkb@microsoft.com>

Author: volksec

server/src/common/api.ts

@@ -5,7 +5,7 @@
 
 import { _, Features, _Connection, _LanguagesImpl } from './server';
 import { SemanticTokensBuilder } from './semanticTokens';
-import type { WorkDoneProgressReporter, WorkDoneProgressServerReporter, ResultProgressReporter } from './progress';
+import { WorkDoneProgressReporter, type WorkDoneProgressServerReporter, type ResultProgressReporter } from './progress';
 
 export * from 'vscode-languageserver-protocol';
 export { WorkDoneProgressReporter, WorkDoneProgressServerReporter, ResultProgressReporter };
@@ -22,4 +22,4 @@ export namespace ProposedFeatures {
 	};
 
 	export type Connection = _Connection<_, _, _, _, _, _, _, _>;
-}
+}

server/src/common/progress.ts

@@ -27,6 +27,15 @@ export interface WorkDoneProgressReporter {
 	done(): void;
 }
 
+export namespace WorkDoneProgressReporter {
+	/**
+	 * Tests whether the given work done progress reporter discards progress.
+	 */
+	export function isNullInstance(reporter: WorkDoneProgressReporter): boolean {
+		return reporter instanceof NullProgressReporter;
+	}
+}
+
 export interface WorkDoneProgressServerReporter extends WorkDoneProgressReporter {
 	readonly token: CancellationToken;
 }

server/src/node/test/connection.test.ts

@@ -10,7 +10,7 @@ import { Duplex } from 'stream';
 import {
 	InitializeParams, InitializeRequest, InitializeResult, createConnection, DidChangeConfigurationNotification,
 	DidChangeConfigurationParams, Connection, DeclarationRequest, DeclarationParams, ProgressToken, WorkDoneProgress,
-	LocationLink
+	LocationLink, WorkDoneProgressReporter
 } from '../main';
 
 class TestStream extends Duplex {
@@ -73,6 +73,7 @@ suite('Connection Tests', () => {
 	test('Ensure work done converted', (done) => {
 		serverConnection.onDeclaration((_params, _cancel, workDone, result) => {
 			assert.ok(workDone !== undefined, 'Work Done token converted.');
+			assert.ok(!WorkDoneProgressReporter.isNullInstance(workDone), 'Work Done token uses a progress reporter.');
 			assert.ok(result === undefined, 'Result token undefined.');
 			done();
 			return [];
@@ -89,7 +90,7 @@ suite('Connection Tests', () => {
 
 	test('Ensure result converted', (done) => {
 		serverConnection.onDeclaration((_params, _cancel, workDone, result) => {
-			assert.ok(workDone === undefined || workDone.constructor.name === 'NullProgressReporter', 'Work Done token undefined or null progress.');
+			assert.ok(WorkDoneProgressReporter.isNullInstance(workDone), 'Work Done token uses a null progress reporter.');
 			assert.ok(result !== undefined, 'Result token converted.');
 			done();
 			return [];
@@ -177,4 +178,4 @@ suite('Connection Tests', () => {
 			done();
 		});
 	});
-});
+});