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Fix a bug in viaMat for Identity flow optimization #22899

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Richard Imaoka 2017-11-13 17:21:46 +09:00 • committed by Johan Andrén
parent cba1cb79fa
commit ad5fa124b3
2 changed files with 36 additions and 9 deletions
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21
akka-stream-tests/src/test/scala/akka/stream/scaladsl/GraphMatValueSpec.scala
View file

@ -5,7 +5,7 @@ package akka.stream.scaladsl
import java.util.concurrent.atomic.AtomicInteger
import akka.NotUsed
import akka.{ Done, NotUsed }
import akka.stream._
import akka.stream.testkit._
@ -235,6 +235,25 @@ class GraphMatValueSpec extends StreamSpec {
m4 should ===(NotUsed)
}
"build more complicated graph with flows optimized for identity flows" in {
val flow1 = Flow.fromSinkAndSourceMat(Sink.ignore, Source.single(1).viaMat(Flow[Int])(Keep.both))(Keep.both)
val (mA, (m1, m2)) = Source.single(8).viaMat(flow1)(Keep.right).to(Sink.ignore).run()
Await.result(mA, 1.second) should ===(Done) //from Sink.ignore
m1 should ===(NotUsed) //from Source.single(1)
m2 should ===(NotUsed) //from Flow[Int]
val flow2 = Flow.fromSinkAndSourceMat(Sink.ignore, Source.maybe[Int].viaMat(Flow[Int])(Keep.left))(Keep.both)
val (mB, m3) = Source.single(8).viaMat(flow2)(Keep.right).to(Sink.ignore).run()
Await.result(mB, 1.second) should ===(Done) //from Sink.ignore
// Fails with ClassCastException if value is wrong
m3.success(None) //from Source.maybe[Int]
val flow3 = Flow.fromSinkAndSourceMat(Sink.ignore, Source.single(1).viaMat(Flow[Int])(Keep.right))(Keep.both)
val (mC, m4) = Source.single(8).viaMat(flow3)(Keep.right).to(Sink.ignore).run()
Await.result(mC, 1.second) should ===(Done) //from Sink.ignore
m4 should ===(NotUsed) //from Flow[Int]
}
"provide a new materialized value for each materialization" in {
// coverage for #23577
val matGen = new AtomicInteger(0)

24
akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala
View file

@ -45,15 +45,23 @@ final class Source[+Out, +Mat](
override def via[T, Mat2](flow: Graph[FlowShape[Out, T], Mat2]): Repr[T] = viaMat(flow)(Keep.left)
override def viaMat[T, Mat2, Mat3](flow: Graph[FlowShape[Out, T], Mat2])(combine: (Mat, Mat2) ⇒ Mat3): Source[T, Mat3] = {
val toAppend =
if (flow.traversalBuilder eq Flow.identityTraversalBuilder)
LinearTraversalBuilder.empty()
if (flow.traversalBuilder eq Flow.identityTraversalBuilder)
if (combine == Keep.left)
//optimization by returning this
this.asInstanceOf[Source[T, Mat3]] //Mat == Mat3, due to Keep.left
else if (combine == Keep.right || combine == Keep.none) // Mat3 = NotUsed
//optimization with LinearTraversalBuilder.empty()
new Source[T, Mat3](
traversalBuilder.append(LinearTraversalBuilder.empty(), flow.shape, combine),
SourceShape(shape.out).asInstanceOf[SourceShape[T]])
else
flow.traversalBuilder
new Source[T, Mat3](
traversalBuilder.append(toAppend, flow.shape, combine),
SourceShape(flow.shape.out))
new Source[T, Mat3](
traversalBuilder.append(flow.traversalBuilder, flow.shape, combine),
SourceShape(flow.shape.out))
else
new Source[T, Mat3](
traversalBuilder.append(flow.traversalBuilder, flow.shape, combine),
SourceShape(flow.shape.out))
}
/**