allow to ignore 'This Generator is empty' error

src/actions/lifecycle.ts

@@ -33,6 +33,7 @@ export abstract class TasksMixin {
   // Queues map: generator's queue name => grouped-queue's queue name (custom name)
   readonly _queues!: Record<string, Priority>;
 
+  customLifecycle?: boolean;
   runningState?: { namespace: string; queueName: string; methodName: string };
   _taskStatus?: TaskStatus;
 
@@ -247,7 +248,7 @@ export abstract class TasksMixin {
     this._taskStatus = { cancelled: false, timestamp: new Date() };
 
     const validMethods = this.getTaskNames();
-    if (validMethods.length === 0 && this._prompts.length === 0) {
+    if (validMethods.length === 0 && this._prompts.length === 0 && !this.customLifecycle) {
       throw new Error('This Generator is empty. Add at least one method for it to run.');
     }
 

test/base.test.ts

@@ -340,6 +340,17 @@ describe('Base', () => {
       });
     });
 
+    it("doesn't throw if no method is available with customLifecycle", async function () {
+      const gen = new (class extends Base {})([], {
+        resolved: 'generator-ember/all/index.js',
+        namespace: 'dummy',
+        env,
+      });
+      gen.customLifecycle = true;
+
+      await gen.run();
+    });
+
     it('will run non-enumerable methods', async function () {
       class Generator extends Base {}