Akka streams graph stage stuck if onPull doesn't push

Hi all,

I’m developing a custom Akka source using GraphStage in Java.
I’m noticing that if during onPull(), no element is pushed, the stage is stuck.
Is my understanding incorrect that onPull() should be called again if no element was pushed?

Thanks!

{
                setHandler(out, new AbstractOutHandler() {
                    @Override
                    public void onPull() throws Exception {
                        if (count++ > 1000) {
                            completeStage();
                            return;
                        }
                        if (count % 2 != 0) {
                            Integer n = rand.nextInt(100);
                            buffer.add(n);
                            push(out, n);
                        } else {
                            // if this block is entered, source will be stuck
                            return;
                        }
                    }
                });
            }

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