fix #33691

extensions/vscode-api-tests/src/window.test.ts

@@ -329,6 +329,23 @@ suite('window namespace tests', () => {
 		return Promise.all([a, b]);
 	});
 
+	test('Default value for showInput Box accepted even if fails validateInput, #33691', function () {
+		const result = window.showInputBox({
+			validateInput: (value: string) => {
+				if (!value || value.trim().length === 0) {
+					return 'Cannot set empty description';
+				}
+				return null;
+			}
+		}).then(value => {
+			assert.equal(value, undefined);
+		});
+
+		const exec = commands.executeCommand('workbench.action.acceptSelectedQuickOpenItem');
+		return Promise.all([result, exec]);
+	});
+
+
 	test('editor, selection change kind', () => {
 		return workspace.openTextDocument(join(workspace.rootPath || '', './far.js')).then(doc => window.showTextDocument(doc)).then(editor => {
 

src/vs/workbench/browser/parts/quickopen/quickOpenController.ts

@@ -169,7 +169,7 @@ export class QuickOpenController extends Component implements IQuickOpenService
 			: nls.localize('inputModeEntry', "Press 'Enter' to confirm your input or 'Escape' to cancel");
 
 		let currentPick = defaultMessage;
-		let currentValidation = TPromise.as(true);
+		let currentValidation: TPromise<boolean>;
 		let currentDecoration: Severity;
 		let lastValue: string;
 
@@ -215,6 +215,17 @@ export class QuickOpenController extends Component implements IQuickOpenService
 		};
 
 		return new TPromise(init).then(item => {
+
+			if (!currentValidation) {
+				if (options.validateInput) {
+					currentValidation = options
+						.validateInput(lastValue === void 0 ? options.value : lastValue)
+						.then(message => !message);
+				} else {
+					currentValidation = TPromise.as(true);
+				}
+			}
+
 			return currentValidation.then(valid => {
 				if (valid && item) {
 					return lastValue === void 0 ? (options.value || '') : lastValue;