Enumerator.onDoneEnumerating doesn't get called when iteratee is done enumerating in play 2.2.1

gistfile1.txt

object EnumeratorFun extends App {

   var counter: Int = 0

   val enumerator = Enumerator.generateM[Int]({
     val ret: Option[Int] = if (counter < 5) {
       counter += 1
       Some(counter)
     } else None
     Future(ret)
   })

  enumerator.onDoneEnumerating(println("Done enumerating. This should get called when its final input has been consumed by Iteratee"))

  val iteratee = Iteratee.foreach[Int](println(_))

  val runComplete = enumerator(iteratee)

  Await.result(runComplete, Duration.Inf)

  println("Finished waiting for iteratee to run on enumerator")

}

Sample case for playframework/playframework#2278

As per comments from Gary, onDoneEnumerating does not modify the existing enumerator, but creates a new enumerator which runs the callback when done (or at an error). Updated case (that works):

object EnumeratorFun extends App {

var counter: Int = 0

val enumerator = Enumerator.generateM[Int]({
val ret: Option[Int] = if %28counter < 5%29 {
counter += 1
Some%28counter%29
} else None
Future%28ret%29
})

val enumWithOnDone = enumerator.onDoneEnumerating(println("Done enumerating. This should get called when its final input has been consumed by Iteratee"))

val iteratee = Iteratee.foreachInt

val runComplete = enumWithOnDone(iteratee)

Await.result(runComplete, Duration.Inf)

println("Finished waiting for iteratee to run on enumerator")

}