Single.zip on empty collection never terminate

[Centaur]

Single.zip(new ArrayList<Single<Integer>>(), i -> i)
          .doAfterTerminate(() -> System.out.println("terminated"))
          .subscribe();

this behavior is different from Observable.zip

Observable.zip(new ArrayList<Observable<Integer>>(), i -> i)
                   .doAfterTerminate(() -> System.out.println("terminated"))
                   .subscribe();

[artem-zinnatullin]

What do you expect it to do? Throw error? Single either emits one result or throws error.

Looks like the best we can do is to throw something like IllegalArgumentException.

[akarnokd]

Observable.zip just completes if there are no sources. If one converts an empty Observable to single, it produces a NoSuchElementException error.

[artem-zinnatullin]

I'll check this and work on PR soon.