java.lang.IllegalStateException: Terminal event already emitted.

[mihab]

I get the following error when trying to merge a few files using

flatMap(list -> OrderedMerge.create(list, comparator));

where list is a List<Observable<java.io.File>> .

on version 0.7.9.24 ( I think our RxJava version is too old for the 0.8.x branch ).

java.lang.IllegalStateException: Terminal event already emitted. at rx.observables.SyncOnSubscribe$SubscriptionProducer.onError(SyncOnSubscribe.java:476) at com.github.davidmoten.rx.Serialized$1.next(Serialized.java:65) at com.github.davidmoten.rx.Serialized$1.next(Serialized.java:47) at rx.observables.SyncOnSubscribe$SubscriptionProducer.nextIteration(SyncOnSubscribe.java:459) at rx.observables.SyncOnSubscribe$SubscriptionProducer.slowPath(SyncOnSubscribe.java:437) at rx.observables.SyncOnSubscribe$SubscriptionProducer.request(SyncOnSubscribe.java:395) at rx.Subscriber.request(Subscriber.java:157) at com.github.davidmoten.rx.internal.operators.OrderedMerge$SourceSubscriber.requestMore(OrderedMerge.java:312) at com.github.davidmoten.rx.internal.operators.OrderedMerge$MergeProducer.emit(OrderedMerge.java:251) at com.github.davidmoten.rx.internal.operators.OrderedMerge$SourceSubscriber.onNext(OrderedMerge.java:336) at rx.internal.operators.OperatorCast$CastSubscriber.onNext(OperatorCast.java:69) at rx.observers.Subscribers$5.onNext(Subscribers.java:235) at rx.internal.operators.OnSubscribeDoOnEach$DoOnEachSubscriber.onNext(OnSubscribeDoOnEach.java:101) at rx.observables.SyncOnSubscribe$SubscriptionProducer.onNext(SyncOnSubscribe.java:490) at com.github.davidmoten.rx.Serialized$1.next(Serialized.java:59) at com.github.davidmoten.rx.Serialized$1.next(Serialized.java:47) at rx.observables.SyncOnSubscribe$SubscriptionProducer.nextIteration(SyncOnSubscribe.java:459) at rx.observables.SyncOnSubscribe$SubscriptionProducer.slowPath(SyncOnSubscribe.java:437) at rx.observables.SyncOnSubscribe$SubscriptionProducer.request(SyncOnSubscribe.java:395) at rx.Subscriber.setProducer(Subscriber.java:211) at rx.internal.operators.OperatorCast$CastSubscriber.setProducer(OperatorCast.java:94) at rx.Subscriber.setProducer(Subscriber.java:205) at rx.Subscriber.setProducer(Subscriber.java:205) at rx.observables.SyncOnSubscribe.call(SyncOnSubscribe.java:62) at rx.observables.SyncOnSubscribe.call(SyncOnSubscribe.java:43) at rx.Observable.unsafeSubscribe(Observable.java:10151) at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:41) at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:30) at rx.Observable.unsafeSubscribe(Observable.java:10151) at rx.internal.operators.OnSubscribeUsing.call(OnSubscribeUsing.java:94) at rx.internal.operators.OnSubscribeUsing.call(OnSubscribeUsing.java:32) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.Observable.unsafeSubscribe(Observable.java:10151) at com.github.davidmoten.rx.internal.operators.OrderedMerge.call(OrderedMerge.java:85) at com.github.davidmoten.rx.internal.operators.OrderedMerge.call(OrderedMerge.java:27) at rx.Observable.unsafeSubscribe(Observable.java:10151) at rx.internal.operators.OperatorMerge$MergeSubscriber.onNext(OperatorMerge.java:251) at rx.internal.operators.OperatorMerge$MergeSubscriber.onNext(OperatorMerge.java:148) at rx.internal.operators.OnSubscribeMap$MapSubscriber.onNext(OnSubscribeMap.java:77) at rx.internal.producers.SingleDelayedProducer.emit(SingleDelayedProducer.java:102) at rx.internal.producers.SingleDelayedProducer.setValue(SingleDelayedProducer.java:85) at rx.internal.operators.OperatorToObservableList$1.onCompleted(OperatorToObservableList.java:98) at rx.internal.operators.OnSubscribeMap$MapSubscriber.onCompleted(OnSubscribeMap.java:97) at rx.internal.operators.OnSubscribeFromIterable$IterableProducer.fastPath(OnSubscribeFromIterable.java:190) at rx.internal.operators.OnSubscribeFromIterable$IterableProducer.request(OnSubscribeFromIterable.java:86) at rx.Subscriber.setProducer(Subscriber.java:211) at rx.internal.operators.OnSubscribeMap$MapSubscriber.setProducer(OnSubscribeMap.java:102) at rx.internal.operators.OnSubscribeFromIterable.call(OnSubscribeFromIterable.java:63) at rx.internal.operators.OnSubscribeFromIterable.call(OnSubscribeFromIterable.java:34) at rx.Observable.unsafeSubscribe(Observable.java:10151) at rx.internal.operators.OnSubscribeMap.call(OnSubscribeMap.java:48) at rx.internal.operators.OnSubscribeMap.call(OnSubscribeMap.java:33) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.Observable.unsafeSubscribe(Observable.java:10151) at rx.internal.operators.OnSubscribeMap.call(OnSubscribeMap.java:48) at rx.internal.operators.OnSubscribeMap.call(OnSubscribeMap.java:33) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.Observable.unsafeSubscribe(Observable.java:10151) at rx.internal.operators.OperatorMerge$MergeSubscriber.onNext(OperatorMerge.java:251) at rx.internal.operators.OperatorMerge$MergeSubscriber.onNext(OperatorMerge.java:148) at rx.internal.operators.OnSubscribeMap$MapSubscriber.onNext(OnSubscribeMap.java:77) at rx.internal.operators.DeferredScalarSubscriber.complete(DeferredScalarSubscriber.java:100) at rx.internal.operators.DeferredScalarSubscriber.onCompleted(DeferredScalarSubscriber.java:73) at rx.internal.operators.OperatorBufferWithSize$BufferExact.onCompleted(OperatorBufferWithSize.java:130) at rx.internal.operators.OnSubscribeDoOnEach$DoOnEachSubscriber.onCompleted(OnSubscribeDoOnEach.java:70) at rx.internal.operators.OnSubscribeDoOnEach$DoOnEachSubscriber.onCompleted(OnSubscribeDoOnEach.java:70) at rx.internal.operators.OperatorMerge$MergeSubscriber.emitLoop(OperatorMerge.java:659) at rx.internal.operators.OperatorMerge$MergeSubscriber.emit(OperatorMerge.java:571) at rx.internal.operators.OperatorMerge$InnerSubscriber.onCompleted(OperatorMerge.java:860) at rx.internal.producers.SingleProducer.request(SingleProducer.java:75) at rx.Subscriber.setProducer(Subscriber.java:211) at rx.internal.operators.OperatorSingle$ParentSubscriber.onCompleted(OperatorSingle.java:110) at rx.internal.operators.DeferredScalarSubscriber.complete(DeferredScalarSubscriber.java:102) at rx.internal.operators.OnSubscribeTakeLastOne$TakeLastOneSubscriber.onCompleted(OnSubscribeTakeLastOne.java:57) at rx.internal.operators.OperatorMerge$MergeSubscriber.emitLoop(OperatorMerge.java:659) at rx.internal.operators.OperatorMerge$MergeSubscriber.emit(OperatorMerge.java:571) at rx.internal.operators.OperatorMerge$InnerSubscriber.onCompleted(OperatorMerge.java:860) at rx.internal.operators.OperatorSwitchIfEmpty$ParentSubscriber.onCompleted(OperatorSwitchIfEmpty.java:70) at rx.internal.operators.OperatorMerge$MergeSubscriber.emitLoop(OperatorMerge.java:659) at rx.internal.operators.OperatorMerge$MergeSubscriber.emit(OperatorMerge.java:571) at rx.internal.operators.OperatorMerge$InnerSubscriber.onCompleted(OperatorMerge.java:860) at rx.internal.operators.OnSubscribeMap$MapSubscriber.onCompleted(OnSubscribeMap.java:97) at rx.internal.operators.OperatorTake$1.onCompleted(OperatorTake.java:56) at rx.internal.operators.OnSubscribeFlattenIterable$FlattenIterableSubscriber.checkTerminated(OnSubscribeFlattenIterable.java:308) at rx.internal.operators.OnSubscribeFlattenIterable$FlattenIterableSubscriber.drain(OnSubscribeFlattenIterable.java:180) at rx.internal.operators.OnSubscribeFlattenIterable$FlattenIterableSubscriber.onCompleted(OnSubscribeFlattenIterable.java:147) at rx.internal.operators.OnSubscribeDoOnEach$DoOnEachSubscriber.onCompleted(OnSubscribeDoOnEach.java:70) at rx.internal.operators.OnSubscribeDoOnEach$DoOnEachSubscriber.onCompleted(OnSubscribeDoOnEach.java:70) at rx.internal.operators.OnSubscribeFlattenIterable$FlattenIterableSubscriber.checkTerminated(OnSubscribeFlattenIterable.java:308) at rx.internal.operators.OnSubscribeFlattenIterable$FlattenIterableSubscriber.drain(OnSubscribeFlattenIterable.java:180) at rx.internal.operators.OnSubscribeFlattenIterable$FlattenIterableSubscriber.onCompleted(OnSubscribeFlattenIterable.java:147) at rx.internal.operators.OnSubscribeRedo$4$1.onCompleted(OnSubscribeRedo.java:321) at rx.internal.operators.OperatorZip$Zip.tick(OperatorZip.java:239) at rx.internal.operators.OperatorZip$Zip$InnerSubscriber.onCompleted(OperatorZip.java:307) at rx.internal.operators.OnSubscribeMap$MapSubscriber.onCompleted(OnSubscribeMap.java:97) at rx.internal.operators.OnSubscribeRedo$3$1.onNext(OnSubscribeRedo.java:298) at rx.internal.operators.OnSubscribeRedo$3$1.onNext(OnSubscribeRedo.java:284) at rx.internal.operators.NotificationLite.accept(NotificationLite.java:152) at rx.subjects.SubjectSubscriptionManager$SubjectObserver.emitNext(SubjectSubscriptionManager.java:255) at rx.subjects.BehaviorSubject.onNext(BehaviorSubject.java:161) at rx.observers.SerializedObserver.onNext(SerializedObserver.java:92) at rx.subjects.SerializedSubject.onNext(SerializedSubject.java:67) at rx.internal.operators.OnSubscribeRedo$2$1.onCompleted(OnSubscribeRedo.java:228) at rx.internal.operators.OperatorOnErrorResumeNextViaFunction$4.onCompleted(OperatorOnErrorResumeNextViaFunction.java:101) at retrofit.RxSupport$2.run(RxSupport.java:57) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at java.lang.Thread.run(Thread.java:745)

it swallows the original Exception:

java.io.IOException: Stream closed at java.io.BufferedInputStream.getBufIfOpen(BufferedInputStream.java:170) at java.io.BufferedInputStream.fill(BufferedInputStream.java:214) at java.io.BufferedInputStream.read(BufferedInputStream.java:265) at java.io.ObjectInputStream$PeekInputStream.peek(ObjectInputStream.java:2303) at java.io.ObjectInputStream$BlockDataInputStream.peek(ObjectInputStream.java:2596) at java.io.ObjectInputStream$BlockDataInputStream.peekByte(ObjectInputStream.java:2606) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1319) at java.io.ObjectInputStream.readObject(ObjectInputStream.java:371) at com.github.davidmoten.rx.Serialized$1.next(Serialized.java:58) at com.github.davidmoten.rx.Serialized$1.next(Serialized.java:47) at rx.observables.SyncOnSubscribe$SubscriptionProducer.nextIteration(SyncOnSubscribe.java:459) at rx.observables.SyncOnSubscribe$SubscriptionProducer.slowPath(SyncOnSubscribe.java:437) at rx.observables.SyncOnSubscribe$SubscriptionProducer.request(SyncOnSubscribe.java:395) at rx.Subscriber.request(Subscriber.java:157) at com.github.davidmoten.rx.internal.operators.OrderedMerge$SourceSubscriber.requestMore(OrderedMerge.java:312) at com.github.davidmoten.rx.internal.operators.OrderedMerge$MergeProducer.emit(OrderedMerge.java:251) at com.github.davidmoten.rx.internal.operators.OrderedMerge$SourceSubscriber.onNext(OrderedMerge.java:336) at rx.internal.operators.OperatorCast$CastSubscriber.onNext(OperatorCast.java:69) at rx.observers.Subscribers$5.onNext(Subscribers.java:235) at rx.internal.operators.OnSubscribeDoOnEach$DoOnEachSubscriber.onNext(OnSubscribeDoOnEach.java:101) at rx.observables.SyncOnSubscribe$SubscriptionProducer.onNext(SyncOnSubscribe.java:490) at com.github.davidmoten.rx.Serialized$1.next(Serialized.java:59) at com.github.davidmoten.rx.Serialized$1.next(Serialized.java:47) at rx.observables.SyncOnSubscribe$SubscriptionProducer.nextIteration(SyncOnSubscribe.java:459) at rx.observables.SyncOnSubscribe$SubscriptionProducer.slowPath(SyncOnSubscribe.java:437) at rx.observables.SyncOnSubscribe$SubscriptionProducer.request(SyncOnSubscribe.java:395) at rx.Subscriber.setProducer(Subscriber.java:211) at rx.internal.operators.OperatorCast$CastSubscriber.setProducer(OperatorCast.java:94) at rx.Subscriber.setProducer(Subscriber.java:205) at rx.Subscriber.setProducer(Subscriber.java:205) at rx.observables.SyncOnSubscribe.call(SyncOnSubscribe.java:62) at rx.observables.SyncOnSubscribe.call(SyncOnSubscribe.java:43) at rx.Observable.unsafeSubscribe(Observable.java:10151) at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:41) at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:30) at rx.Observable.unsafeSubscribe(Observable.java:10151) at rx.internal.operators.OnSubscribeUsing.call(OnSubscribeUsing.java:94) at rx.internal.operators.OnSubscribeUsing.call(OnSubscribeUsing.java:32) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.Observable.unsafeSubscribe(Observable.java:10151) at com.github.davidmoten.rx.internal.operators.OrderedMerge.call(OrderedMerge.java:85) at com.github.davidmoten.rx.internal.operators.OrderedMerge.call(OrderedMerge.java:27) at rx.Observable.unsafeSubscribe(Observable.java:10151) at rx.internal.operators.OperatorMerge$MergeSubscriber.onNext(OperatorMerge.java:251) at rx.internal.operators.OperatorMerge$MergeSubscriber.onNext(OperatorMerge.java:148) at rx.internal.operators.OnSubscribeMap$MapSubscriber.onNext(OnSubscribeMap.java:77) at rx.internal.producers.SingleDelayedProducer.emit(SingleDelayedProducer.java:102) at rx.internal.producers.SingleDelayedProducer.setValue(SingleDelayedProducer.java:85) at rx.internal.operators.OperatorToObservableList$1.onCompleted(OperatorToObservableList.java:98) at rx.internal.operators.OnSubscribeMap$MapSubscriber.onCompleted(OnSubscribeMap.java:97) at rx.internal.operators.OnSubscribeFromIterable$IterableProducer.fastPath(OnSubscribeFromIterable.java:190) at rx.internal.operators.OnSubscribeFromIterable$IterableProducer.request(OnSubscribeFromIterable.java:86) at rx.Subscriber.setProducer(Subscriber.java:211) at rx.internal.operators.OnSubscribeMap$MapSubscriber.setProducer(OnSubscribeMap.java:102) at rx.internal.operators.OnSubscribeFromIterable.call(OnSubscribeFromIterable.java:63) at rx.internal.operators.OnSubscribeFromIterable.call(OnSubscribeFromIterable.java:34) at rx.Observable.unsafeSubscribe(Observable.java:10151) at rx.internal.operators.OnSubscribeMap.call(OnSubscribeMap.java:48) at rx.internal.operators.OnSubscribeMap.call(OnSubscribeMap.java:33) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.Observable.unsafeSubscribe(Observable.java:10151) at rx.internal.operators.OnSubscribeMap.call(OnSubscribeMap.java:48) at rx.internal.operators.OnSubscribeMap.call(OnSubscribeMap.java:33) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.Observable.unsafeSubscribe(Observable.java:10151) at rx.internal.operators.OperatorMerge$MergeSubscriber.onNext(OperatorMerge.java:251) at rx.internal.operators.OperatorMerge$MergeSubscriber.onNext(OperatorMerge.java:148) at rx.internal.operators.OnSubscribeMap$MapSubscriber.onNext(OnSubscribeMap.java:77) at rx.internal.operators.DeferredScalarSubscriber.complete(DeferredScalarSubscriber.java:100) at rx.internal.operators.DeferredScalarSubscriber.onCompleted(DeferredScalarSubscriber.java:73) at rx.internal.operators.OperatorBufferWithSize$BufferExact.onCompleted(OperatorBufferWithSize.java:130) at rx.internal.operators.OnSubscribeDoOnEach$DoOnEachSubscriber.onCompleted(OnSubscribeDoOnEach.java:70) at rx.internal.operators.OnSubscribeDoOnEach$DoOnEachSubscriber.onCompleted(OnSubscribeDoOnEach.java:70) at rx.internal.operators.OperatorMerge$MergeSubscriber.emitLoop(OperatorMerge.java:659) at rx.internal.operators.OperatorMerge$MergeSubscriber.emit(OperatorMerge.java:571) at rx.internal.operators.OperatorMerge$InnerSubscriber.onCompleted(OperatorMerge.java:860) at rx.internal.producers.SingleProducer.request(SingleProducer.java:75) at rx.Subscriber.setProducer(Subscriber.java:211) at rx.internal.operators.OperatorSingle$ParentSubscriber.onCompleted(OperatorSingle.java:110) at rx.internal.operators.DeferredScalarSubscriber.complete(DeferredScalarSubscriber.java:102) at rx.internal.operators.OnSubscribeTakeLastOne$TakeLastOneSubscriber.onCompleted(OnSubscribeTakeLastOne.java:57) at rx.internal.operators.OperatorMerge$MergeSubscriber.emitLoop(OperatorMerge.java:659) at rx.internal.operators.OperatorMerge$MergeSubscriber.emit(OperatorMerge.java:571) at rx.internal.operators.OperatorMerge$InnerSubscriber.onCompleted(OperatorMerge.java:860) at rx.internal.operators.OperatorSwitchIfEmpty$ParentSubscriber.onCompleted(OperatorSwitchIfEmpty.java:70) at rx.internal.operators.OperatorMerge$MergeSubscriber.emitLoop(OperatorMerge.java:659) at rx.internal.operators.OperatorMerge$MergeSubscriber.emit(OperatorMerge.java:571) at rx.internal.operators.OperatorMerge$InnerSubscriber.onCompleted(OperatorMerge.java:860) at rx.internal.operators.OnSubscribeMap$MapSubscriber.onCompleted(OnSubscribeMap.java:97) at rx.internal.operators.OnSubscribeDoOnEach$DoOnEachSubscriber.onCompleted(OnSubscribeDoOnEach.java:70) at rx.internal.operators.OperatorOnErrorResumeNextViaFunction$4.onCompleted(OperatorOnErrorResumeNextViaFunction.java:101) at rx.internal.operators.OnSubscribeDoOnEach$DoOnEachSubscriber.onCompleted(OnSubscribeDoOnEach.java:70) at retrofit.RxSupport$2.run(RxSupport.java:57) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180) at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at java.lang.Thread.run(Thread.java:745)

Did anyone else experience such an issue?

[davidmoten]

Thanks for the report, I'll have a look.

[mihab]

Thanks a lot, if you need anymore information.

I was debugging a bit today and since we use the Serialized class to read, if I read 10 files I can clearly see 10 EOFException events terminating the chain:

rxjava-extras/src/main/java/com/github/davidmoten/rx/Serialized.java

Line 60 in ec425f3

} catch (EOFException e) {

However the chain seems to keep on reading all 10 files after that which of course fails since the stream is closed already:

rxjava-extras/src/main/java/com/github/davidmoten/rx/Serialized.java

Line 64 in ec425f3

} catch (IOException e) {

it looks like an issue with double subscription/reading, though I cannot pinpoint it where.

[davidmoten]

Yeah, I can see quite a bit from the stack trace on this one and that is what I assumed was happening. Serialized looks fine. I'm looking at SyncOnSubscribe and OrderedMerge.

…

On 18 May 2017 at 23:03, Miha Blazin ***@***.***> wrote: Thanks a lot, if you need anymore information. I was debugging a bit today and since we use the Serialized class to read, if I read 10 files I can clearly see 10 EOFException events terminating the chain: https://github.com/davidmoten/rxjava-extras/blob/ ec425f3/src/main/java/com/ github/davidmoten/rx/Serialized.java#L60 However the chain seems to keep on reading all 10 files after that which of course fails since the stream is closed already: https://github.com/davidmoten/rxjava-extras/blob/ ec425f3/src/main/java/com/ github/davidmoten/rx/Serialized.java#L64 it looks like an issue with double subscription/reading, though I cannot pinpoint it where. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#25 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AATa68w5qvfC_1GCZQNp246KyoNIhqlSks5r7EGsgaJpZM4NeF3K> .

[davidmoten]

Can you distill this to a repeatable unit test?

[davidmoten]

I can see an improvement to make to OrderedMerge to ensure that SourceSubscriber does not emit multiple terminal events but I'd like to have a unit test to ensure that that is the cause of the problem (I'm not convinced yet).

[davidmoten]

Supposing I do come up with a fix for this what do you want to do about it? Upgrade to latest? Patch your existing app with fixes to a single class?

[mihab]

I will try to make a repeatable Unit Test case. In case it does get fixed, I would expect a hotfix version of the 0.7.x branch ... as in 0.7.9.25.