-str - Removes Source.unfoldInf

Motivation: Since it can be easily implemented inline on top of unfold

akka-stream-tests/src/test/scala/akka/stream/FusingSpec.scala

@@ -10,7 +10,7 @@ import org.scalactic.ConversionCheckedTripleEquals
 import akka.stream.Attributes._
 import akka.stream.Fusing.FusedGraph
 import scala.annotation.tailrec
-import akka.stream.impl.StreamLayout.Module
+import akka.stream.impl.StreamLayout.{ CopiedModule, Module }
 import org.scalatest.concurrent.ScalaFutures
 import scala.concurrent.duration._
 import akka.stream.impl.fusing.GraphInterpreter
@@ -23,7 +23,7 @@ class FusingSpec extends AkkaSpec with ScalaFutures with ConversionCheckedTriple
   implicit val patience = PatienceConfig(1.second)
 
   def graph(async: Boolean) =
-    Source.unfoldInf(1)(x ⇒ (x, x)).filter(_ % 2 == 1)
+    Source.unfold(1)(x ⇒ Some(x -> x)).filter(_ % 2 == 1)
       .alsoTo(Flow[Int].fold(0)(_ + _).to(Sink.head.named("otherSink")).addAttributes(if (async) Attributes.asyncBoundary else Attributes.none))
       .via(Flow[Int].fold(1)(_ + _).named("mainSink"))
 
@@ -36,13 +36,13 @@ class FusingSpec extends AkkaSpec with ScalaFutures with ConversionCheckedTriple
 
     @tailrec def rec(curr: Module): Unit = {
       if (Debug) println(extractName(curr, "unknown"))
-      if (curr.attributes.contains(to)) () // done
+      curr match {
-      else {
+        case CopiedModule(_, attributes, copyOf) if (attributes and copyOf.attributes).contains(to) ⇒ ()
+        case other if other.attributes.contains(to) ⇒ ()
+        case _ ⇒
           val outs = curr.inPorts.map(ups)
           outs.size should ===(1)
-        val out = outs.head
+          rec(owner(outs.head))
-        val next = owner(out)
-        rec(next)
       }
     }
 
@@ -57,8 +57,8 @@ class FusingSpec extends AkkaSpec with ScalaFutures with ConversionCheckedTriple
       module.downstreams.size should ===(modules - 1)
       module.info.downstreams.size should be >= downstreams
       module.info.upstreams.size should be >= downstreams
-      singlePath(fused, Attributes.Name("mainSink"), Attributes.Name("unfoldInf"))
+      singlePath(fused, Attributes.Name("mainSink"), Attributes.Name("unfold"))
-      singlePath(fused, Attributes.Name("otherSink"), Attributes.Name("unfoldInf"))
+      singlePath(fused, Attributes.Name("otherSink"), Attributes.Name("unfold"))
     }
 
     "fuse a moderately complex graph" in {

akka-stream-tests/src/test/scala/akka/stream/scaladsl/SourceSpec.scala

@@ -252,7 +252,7 @@ class SourceSpec extends AkkaSpec with DefaultTimeout with ScalaFutures {
     }
 
     "generate an unbounded fibonacci sequence" in {
-      Source.unfoldInf((0, 1))({ case (a, b) ⇒ (b, a + b) → a })
+      Source.unfold((0, 1))({ case (a, b) ⇒ Some((b, a + b) → a) })
         .take(36)
         .runFold(List.empty[Int]) { case (xs, x) ⇒ x :: xs }
         .futureValue should ===(expected)

akka-stream/src/main/scala/akka/stream/impl/Stages.scala

@@ -65,7 +65,6 @@ private[stream] object Stages {
     val repeat = name("repeat")
     val unfold = name("unfold")
     val unfoldAsync = name("unfoldAsync")
-    val unfoldInf = name("unfoldInf")
 
     val publisherSource = name("publisherSource")
     val iterableSource = name("iterableSource")

akka-stream/src/main/scala/akka/stream/impl/Unfold.scala

@@ -3,10 +3,11 @@
  */
 package akka.stream.scaladsl
 
+import akka.stream.impl.Stages.DefaultAttributes
 import akka.stream.stage.{ OutHandler, GraphStageLogic, GraphStage }
 import akka.stream._
 
-import scala.concurrent.{ ExecutionContext, Future }
+import scala.concurrent.Future
 import scala.util.{ Failure, Success, Try }
 
 /**
@@ -15,7 +16,7 @@ import scala.util.{ Failure, Success, Try }
 private[akka] final class Unfold[S, E](s: S, f: S ⇒ Option[(S, E)]) extends GraphStage[SourceShape[E]] {
   val out: Outlet[E] = Outlet("Unfold.out")
   override val shape: SourceShape[E] = SourceShape(out)
-
+  override def initialAttributes: Attributes = DefaultAttributes.unfold
   override def createLogic(inheritedAttributes: Attributes): GraphStageLogic =
     new GraphStageLogic(shape) {
       private[this] var state = s
@@ -38,7 +39,7 @@ private[akka] final class Unfold[S, E](s: S, f: S ⇒ Option[(S, E)]) extends Gr
 private[akka] final class UnfoldAsync[S, E](s: S, f: S ⇒ Future[Option[(S, E)]]) extends GraphStage[SourceShape[E]] {
   val out: Outlet[E] = Outlet("UnfoldAsync.out")
   override val shape: SourceShape[E] = SourceShape(out)
-
+  override def initialAttributes: Attributes = DefaultAttributes.unfoldAsync
   override def createLogic(inheritedAttributes: Attributes): GraphStageLogic =
     new GraphStageLogic(shape) {
       private[this] var state = s

akka-stream/src/main/scala/akka/stream/javadsl/Source.scala

@@ -184,13 +184,6 @@ object Source {
   def unfoldAsync[S, E](s: S, f: function.Function[S, Future[Option[(S, E)]]]): Source[E, Unit] =
     new Source(scaladsl.Source.unfoldAsync(s)((s: S) ⇒ f.apply(s)))
 
-  /**
-   * Simpler [[unfold]], for infinite sequences.
-   */
-  def unfoldInf[S, E](s: S, f: function.Function[S, (S, E)]): Source[E, Unit] = {
-    new Source(scaladsl.Source.unfoldInf(s)((s: S) ⇒ f.apply(s)))
-  }
-
   /**
    * Create a `Source` that immediately ends the stream with the `cause` failure to every connected `Sink`.
    */

akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala

@@ -260,7 +260,7 @@ object Source {
    * }}}
    */
   def unfold[S, E](s: S)(f: S ⇒ Option[(S, E)]): Source[E, Unit] =
-    Source.fromGraph(new Unfold(s, f)).withAttributes(DefaultAttributes.unfold)
+    Source.fromGraph(new Unfold(s, f))
 
   /**
    * Same as [[unfold]], but uses an async function to generate the next state-element tuple.
@@ -278,19 +278,7 @@ object Source {
    * }}}
    */
   def unfoldAsync[S, E](s: S)(f: S ⇒ Future[Option[(S, E)]]): Source[E, Unit] =
-    Source.fromGraph(new UnfoldAsync(s, f)).withAttributes(DefaultAttributes.unfoldAsync)
+    Source.fromGraph(new UnfoldAsync(s, f))
-
-  /**
-   * Simpler [[unfold]], for infinite sequences.
-   *
-   * {{{
-   *   Source.unfoldInf(0 → 1) {
-   *    case (a, b) ⇒ (b → (a + b)) → a
-   *   }
-   * }}}
-   */
-  def unfoldInf[S, E](s: S)(f: S ⇒ (S, E)): Source[E, Unit] =
-    unfold(s)(s ⇒ Some(f(s))).withAttributes(DefaultAttributes.unfoldInf)
 
   /**
    * A `Source` with no elements, i.e. an empty stream that is completed immediately for every connected `Sink`.