fix(core): ensure takeUntilDestroyed unregisters onDestroy listener o…

…n unsubscribe (#49901)

The takeUntilDestroyed must always remove the onDestroy listener,
in the teardown logic.

PR Close #49901

packages/core/rxjs-interop/src/take_until_destroyed.ts

@@ -27,7 +27,8 @@ export function takeUntilDestroyed<T>(destroyRef?: DestroyRef): MonoTypeOperator
  }
 
  const destroyed$ = new Observable<void>(observer => {
- destroyRef!.onDestroy(observer.next.bind(observer));
+ const unregisterFn = destroyRef!.onDestroy(observer.next.bind(observer));
+ return unregisterFn;
  });
 
  return <T>(source: Observable<T>) => {

packages/core/rxjs-interop/test/take_until_destroyed_spec.ts

@@ -63,4 +63,17 @@ describe('takeUntilDestroyed', () => {
  source$.next(2);
  expect(last).toBe(1);
  });
+
+ it('should unregister listener if observable is unsubscribed', () => {
+ const injector = Injector.create({providers: []}) as EnvironmentInjector;
+ const destroyRef = injector.get(DestroyRef);
+ const unregisterFn = jasmine.createSpy();
+ spyOn(destroyRef, 'onDestroy').and.returnValue(unregisterFn);
+
+ const subscription = new BehaviorSubject(0).pipe(takeUntilDestroyed(destroyRef)).subscribe();
+
+ subscription.unsubscribe();
+
+ expect(unregisterFn).toHaveBeenCalled();
+ });
 });