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Merge pull request #20611 from drewhk/wip-20564-classcastex-in-graphDSL-drewhk

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#20564 Fix compose method of EmptyModule to be able to Keep.left or right
This commit is contained in:
drewhk 2016-05-31 14:56:33 +02:00
commit d08cf51227
4 changed files with 72 additions and 6 deletions
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41
akka-stream-tests/src/test/scala/akka/stream/scaladsl/GraphMatValueSpec.scala
View file

@ -169,6 +169,47 @@ class GraphMatValueSpec extends AkkaSpec {
done should ===(true)
}
"ignore materialized values for a graph with no materialized values exposed" in {
// The bug here was that the default behavior for "compose" in Module is Keep.left, but
// EmptyModule.compose broke this by always returning the other module intact, which means
// that the materialized value was that of the other module (which is inconsistent with Keep.left behavior).
val sink = Sink.ignore
val g = RunnableGraph.fromGraph(GraphDSL.create() { implicit builder: GraphDSL.Builder[NotUsed] ⇒
import GraphDSL.Implicits._
val s = builder.add(sink)
val src = builder.add(Source(1 to 3))
val flow = builder.add(Flow[Int])
src ~> flow ~> s
ClosedShape
})
val result = g.run()
}
"ignore materialized values for a graph with no materialized values exposed, but keep side-effects" in {
// The bug here was that the default behavior for "compose" in Module is Keep.left, but
// EmptyModule.compose broke this by always returning the other module intact, which means
// that the materialized value was that of the other module (which is inconsistent with Keep.left behavior).
val sink = Sink.ignore.mapMaterializedValue(_ ⇒ testActor ! "side effect!")
val g = RunnableGraph.fromGraph(GraphDSL.create() { implicit builder: GraphDSL.Builder[NotUsed] ⇒
import GraphDSL.Implicits._
val s = builder.add(sink)
val src = builder.add(Source(1 to 3))
val flow = builder.add(Flow[Int])
src ~> flow ~> s
ClosedShape
})
var result = g.run()
expectMsg("side effect!")
}
}
}

2
akka-stream/src/main/boilerplate/akka/stream/scaladsl/GraphApply.scala.template
View file

@ -26,7 +26,7 @@ trait GraphApply {
*/
def create[S <: Shape, Mat](g1: Graph[Shape, Mat])(buildBlock: GraphDSL.Builder[Mat] ⇒ (g1.Shape) ⇒ S): Graph[S, Mat] = {
val builder = new GraphDSL.Builder
val s1 = builder.add(g1)
val s1 = builder.add(g1, Keep.right)
val s = buildBlock(builder)(s1)
val mod = builder.module.replaceShape(s)

31
akka-stream/src/main/scala/akka/stream/impl/StreamLayout.scala
View file

@ -170,6 +170,7 @@ object StreamLayout {
/**
* Fuses this Module to `that` Module by wiring together `from` and `to`,
* retaining the materialized value of `this` in the result
*
* @param that a Module to fuse with
* @param from the data source to wire
* @param to the data sink to wire
@ -182,6 +183,7 @@ object StreamLayout {
* Fuses this Module to `that` Module by wiring together `from` and `to`,
* transforming the materialized values of `this` and `that` using the
* provided function `f`
*
* @param that a Module to fuse with
* @param from the data source to wire
* @param to the data sink to wire
@ -242,6 +244,7 @@ object StreamLayout {
* Creates a new Module which is `this` Module composed with `that` Module,
* using the given function `f` to compose the materialized value of `this` with
* the materialized value of `that`.
*
* @param that a Module to be composed with (cannot be itself)
* @param f a function which combines the materialized values
* @tparam A the type of the materialized value of `this`
@ -345,10 +348,32 @@ object StreamLayout {
if (s != shape) throw new UnsupportedOperationException("cannot replace the shape of the EmptyModule")
else this
override def compose(that: Module): Module = that
override def compose(that: Module): Module = compose(that, scaladsl.Keep.left)
override def compose[A, B, C](that: Module, f: (A, B) ⇒ C): Module =
throw new UnsupportedOperationException("It is invalid to combine materialized value with EmptyModule")
override def compose[A, B, C](that: Module, f: (A, B) ⇒ C): Module = {
if (f eq scaladsl.Keep.right) {
that
} else if (f eq scaladsl.Keep.left) {
// If "that" has a fully ignorable materialized value, we ignore it, otherwise we keep the side effect and
// explicitly map to NotUsed
val mat =
if (IgnorableMatValComp(that))
Ignore
else
Transform(_ => NotUsed, that.materializedValueComputation)
CompositeModule(
if (that.isSealed) Set(that) else that.subModules,
that.shape,
that.downstreams,
that.upstreams,
mat,
if (this.isSealed) Attributes.none else attributes)
} else {
throw new UnsupportedOperationException("It is invalid to combine materialized value with EmptyModule " +
"except with Keep.left or Keep.right")
}
}
override def withAttributes(attributes: Attributes): Module =
throw new UnsupportedOperationException("EmptyModule cannot carry attributes")

4
akka-stream/src/main/scala/akka/stream/scaladsl/Graph.scala
View file

@ -913,7 +913,7 @@ object GraphDSL extends GraphApply {
def add[S <: Shape](graph: Graph[S, _]): S = {
if (StreamLayout.Debug) StreamLayout.validate(graph.module)
val copy = graph.module.carbonCopy
moduleInProgress = moduleInProgress.compose(copy)
moduleInProgress = moduleInProgress.compose(copy, Keep.left)
graph.shape.copyFromPorts(copy.shape.inlets, copy.shape.outlets).asInstanceOf[S]
}
@ -926,7 +926,7 @@ object GraphDSL extends GraphApply {
private[stream] def add[S <: Shape, A](graph: Graph[S, _], transform: (A) ⇒ Any): S = {
if (StreamLayout.Debug) StreamLayout.validate(graph.module)
val copy = graph.module.carbonCopy
moduleInProgress = moduleInProgress.compose(copy.transformMaterializedValue(transform.asInstanceOf[Any ⇒ Any]))
moduleInProgress = moduleInProgress.compose(copy.transformMaterializedValue(transform.asInstanceOf[Any ⇒ Any]), Keep.right)
graph.shape.copyFromPorts(copy.shape.inlets, copy.shape.outlets).asInstanceOf[S]
}