allow to reuse a menu id and only to create one when none with the id exists (microsoft#155042)

fixes microsoft#155030

Author: jrieken

src/vs/platform/actions/common/actions.ts

@@ -45,7 +45,7 @@ export function isISubmenuItem(item: IMenuItem | ISubmenuItem): item is ISubmenu
 
 export class MenuId {
 
-	private static readonly _idPool = new Set<string>();
+	private static readonly _instances = new Map<string, MenuId>();
 
 	static readonly CommandPalette = new MenuId('CommandPalette');
 	static readonly DebugBreakpointsContext = new MenuId('DebugBreakpointsContext');
@@ -162,14 +162,25 @@ export class MenuId {
 	static readonly NewFile = new MenuId('NewFile');
 	static readonly MergeToolbar = new MenuId('MergeToolbar');
 
+	/**
+	 * Create or reuse a `MenuId` with the given identifier
+	 */
+	static for(identifier: string): MenuId {
+		return MenuId._instances.get(identifier) ?? new MenuId(identifier);
+	}
 
 	readonly id: string;
 
+	/**
+	 * Create a new `MenuId` with the unique identifier. Will throw if a menu
+	 * with the identifier already exists, use `MenuId.for(ident)` or a unique
+	 * identifier
+	 */
 	constructor(identifier: string) {
-		if (MenuId._idPool.has(identifier)) {
-			throw new Error(`Duplicate menu identifier ${identifier}`);
+		if (MenuId._instances.has(identifier)) {
+			throw new TypeError(`MenuId with identifier '${identifier}' already exists. Use MenuId.for(ident) or a unique identifier`);
 		}
-		MenuId._idPool.add(identifier);
+		MenuId._instances.set(identifier, this);
 		this.id = identifier;
 	}
 }

src/vs/platform/actions/test/common/menuService.test.ts

@@ -202,4 +202,13 @@ suite('MenuService', function () {
 		assert.strictEqual(foundA, true);
 		assert.strictEqual(foundB, true);
 	});
+
+	test('Extension contributed submenus missing with errors in output #155030', function () {
+
+		const id = generateUuid();
+		const menu = new MenuId(id);
+
+		assert.throws(() => new MenuId(id));
+		assert.ok(menu === MenuId.for(id));
+	});
 });

src/vs/workbench/services/actions/common/menusExtensionPoint.ts

@@ -717,7 +717,7 @@ submenusExtensionPoint.setHandler(extensions => {
 			}
 
 			const item: IRegisteredSubmenu = {
-				id: new MenuId(`api:${submenuInfo.id}`),
+				id: MenuId.for(`api:${submenuInfo.id}`),
 				label: submenuInfo.label,
 				icon: absoluteIcon
 			};