SubmissionPublisher - Subscriber#onComplete() not invoked when publisher is closed

[Michael McMahon]

Sounds like a bug. It seems like the fact there isn't a call to 
Subscription.request()
is what causes the problem. But by my reading of the spec, 
Subscriber.onComplete()
should still be called, as it is known that " no additional Subscriber 
method invocations will occur".

- Michael.

On 21/02/2017, 09:24, Pavel Bucek wrote:
> there is a formatting issue in the code snippet, publisher.close() 
> should be on the new line:
>
> {
>     SubmissionPublisher<String> publisher =new SubmissionPublisher<>();
>     publisher.subscribe(new Flow.Subscriber<String>() {
>         @Override public void onSubscribe(Flow.Subscription 
> subscription) { }
>
>         @Override public void onNext(String item) { }
>
>         @Override public void onError(Throwable throwable) {
>             System.out.println("onError()");
>         }
>
>         @Override public void onComplete() {
>             System.out.println("onComplete()");
>         }
>     });
>     publisher.submit("item");// if this is commented out, #onComplete 
> is invoked.
>
>     publisher.close();
> }
>
>
> On 21/02/2017 10:16, Pavel Bucek wrote:
>> Hi all,
>>
>> firstly - please let me know if this is is a wrong place to send 
>> this; I wasn't able to find list specific to concurrency.
>>
>> Consider following example:
>>
>> {
>>     SubmissionPublisher<String> publisher =new SubmissionPublisher<>();
>>     publisher.subscribe(new Flow.Subscriber<String>() {
>>         @Override public void onSubscribe(Flow.Subscription 
>> subscription) { }
>>
>>         @Override public void onNext(String item) { }
>>
>>         @Override public void onError(Throwable throwable) {
>>             System.out.println("onError()");
>>         }
>>
>>         @Override public void onComplete() {
>>             System.out.println("onComplete()");
>>         }
>>     });
>>     publisher.submit("item");// if this is commented out, #onComplete 
>> is invoked. publisher.close();
>> }
>>
>> I'd expect that Subscriber#onComplete is invoked after calling 
>> publisher.close(), but it is not happening. Curiously, when I comment 
>> out 'publisher.submit("item")', Subscriber#onComplete is indeed invoked.
>>
>> SubmissionPublisher#close() javadoc says:
>>
>> /** * Unless already closed, issues {@link * 
>> Flow.Subscriber#onComplete() onComplete} signals to current * 
>> subscribers, and disallows subsequent attempts to publish. * Upon 
>> return, this method does <em>NOT</em>guarantee that all * subscribers 
>> have yet completed. */
>>
>> So it seems like it will be invoked in different thread or something 
>> like that, but it is not invoked ever (or more precisely - not during 
>> 10 second after the publisher is closed. There is nothing else 
>> running on that particular jvm instance).
>>
>> Also, publisher#isClosed() returns true and 
>> publisher#getNumberOfSubscribers() returns 0.
>>
>> I'm using Java(TM) SE Runtime Environment (build 
>> 9-ea+157-jigsaw-nightly-h6115-20170219)
>>
>> What am I doing wrong?
>>
>> Thanks and regards, Pavel
>>
>