Allowing market orders causes occasional bugs!

[davidrpugh]

Here is an example of the stack trace...

[ERROR] [12/15/2015 14:16:21.061] [model-market-dispatcher-6] [akka://model/user/$b/clearing-mechanism] next on empty iterator
java.util.NoSuchElementException: next on empty iterator
    at scala.collection.immutable.RedBlackTree$TreeIterator.next(RedBlackTree.scala:475)
    at scala.collection.IterableLike$class.head(IterableLike.scala:107)
    at scala.collection.mutable.TreeSet.head(TreeSet.scala:41)
    at scala.collection.TraversableLike$class.headOption(TraversableLike.scala:440)
    at scala.collection.mutable.TreeSet.headOption(TreeSet.scala:41)
    at markets.clearing.engines.CDAMatchingEngine.accumulateBidOrders(CDAMatchingEngine.scala:108)
    at markets.clearing.engines.CDAMatchingEngine.findMatch(CDAMatchingEngine.scala:66)
    at markets.clearing.ClearingMechanismLike$$anonfun$clearingMechanismBehavior$1.applyOrElse(ClearingMechanismLike.scala:39)
    at scala.PartialFunction$OrElse.applyOrElse(PartialFunction.scala:170)
    at akka.actor.Actor$class.aroundReceive(Actor.scala:480)
    at markets.clearing.ClearingMechanismActor.aroundReceive(ClearingMechanismActor.scala:39)
    at akka.actor.ActorCell.receiveMessage(ActorCell.scala:526)
    at akka.actor.ActorCell.invoke(ActorCell.scala:495)
    at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:257)
    at akka.dispatch.Mailbox.run(Mailbox.scala:224)
    at akka.dispatch.Mailbox.exec(Mailbox.scala:234)
    at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
    at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
    at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
    at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)

Here is the application.conf file used to generate the bug. Bug appeared as soon as I started allowing market orders. This suggests that bug occurs when either askOrderBook or bidOrderBook is empty?

Possibly a bug with TreeSet? Seems unlikely...

[davidrpugh]

I can no longer replicate this issue so I am going to close for now...

[davidrpugh]

I have found the source of this issue: my stupidity. I was creating a single (mutable!) MatchingEngine object and passing it around to a bunch of market actors creating that were mutating it concurrently! Bad...

[davidrpugh]

I forgot to close this issue! Solved it a while back...