+str #17702: Add Keep.none

akka-http-core/src/main/scala/akka/http/impl/engine/server/HttpServerBluePrint.scala

@@ -296,7 +296,7 @@ private[http] object HttpServerBluePrint {
     val flow =
       Flow[ByteString]
         .transform[FrameEvent](() ⇒ new FrameEventParser)
-        .via(Flow.wrap(sink, source)((_, _) ⇒ ()))
+        .via(Flow.wrap(sink, source)(Keep.none))
         .transform(() ⇒ new FrameEventRenderer)
 
     new WebsocketSetup {

akka-http-core/src/test/scala/akka/http/impl/engine/ws/WebsocketServerSpec.scala

@@ -6,7 +6,7 @@ package akka.http.impl.engine.ws
 
 import akka.http.impl.engine.ws.Protocol.Opcode
 import akka.http.scaladsl.model.ws._
-import akka.stream.scaladsl.{ Sink, Flow, Source }
+import akka.stream.scaladsl.{ Keep, Sink, Flow, Source }
 import akka.stream.testkit.Utils
 import akka.util.ByteString
 import org.scalatest.{ Matchers, FreeSpec }
@@ -42,7 +42,7 @@ class WebsocketServerSpec extends FreeSpec with Matchers with WithMaterializerSp
 
           val source =
             Source(List(1, 2, 3, 4, 5)).map(num ⇒ TextMessage.Strict(s"Message $num"))
-          val handler = Flow.wrap(Sink.ignore, source)((_, _) ⇒ ())
+          val handler = Flow.wrap(Sink.ignore, source)(Keep.none)
           val response = upgrade.get.handleMessages(handler)
           responsesSub.sendNext(response)
 

akka-stream-tests/src/test/scala/akka/stream/impl/StreamLayoutSpec.scala

@@ -27,8 +27,6 @@ class StreamLayoutSpec extends AkkaSpec {
   def testSource(): Module = testAtomic(0, 1)
   def testSink(): Module = testAtomic(1, 0)
 
-  val ignore: (Any, Any) ⇒ Any = (x, y) ⇒ ()
-
   "StreamLayout" must {
 
     "be able to model simple linear stages" in {
@@ -42,7 +40,7 @@ class StreamLayoutSpec extends AkkaSpec {
       stage1.isSource should be(false)
 
       val stage2 = testStage()
-      val flow12 = stage1.grow(stage2, ignore).connect(stage1.outPorts.head, stage2.inPorts.head)
+      val flow12 = stage1.grow(stage2, Keep.none).connect(stage1.outPorts.head, stage2.inPorts.head)
 
       flow12.inPorts should be(stage1.inPorts)
       flow12.outPorts should be(stage2.outPorts)
@@ -67,7 +65,7 @@ class StreamLayoutSpec extends AkkaSpec {
       sink3.isSink should be(true)
       sink3.isSource should be(false)
 
-      val source012 = source0.grow(flow12, ignore).connect(source0.outPorts.head, flow12.inPorts.head)
+      val source012 = source0.grow(flow12, Keep.none).connect(source0.outPorts.head, flow12.inPorts.head)
       source012.inPorts.size should be(0)
       source012.outPorts should be(flow12.outPorts)
       source012.isRunnable should be(false)
@@ -75,7 +73,7 @@ class StreamLayoutSpec extends AkkaSpec {
       source012.isSink should be(false)
       source012.isSource should be(true)
 
-      val sink123 = flow12.grow(sink3, ignore).connect(flow12.outPorts.head, sink3.inPorts.head)
+      val sink123 = flow12.grow(sink3, Keep.none).connect(flow12.outPorts.head, sink3.inPorts.head)
       sink123.inPorts should be(flow12.inPorts)
       sink123.outPorts.size should be(0)
       sink123.isRunnable should be(false)
@@ -83,13 +81,13 @@ class StreamLayoutSpec extends AkkaSpec {
       sink123.isSink should be(true)
       sink123.isSource should be(false)
 
-      val runnable0123a = source0.grow(sink123, ignore).connect(source0.outPorts.head, sink123.inPorts.head)
-      val runnable0123b = source012.grow(sink3, ignore).connect(source012.outPorts.head, sink3.inPorts.head)
+      val runnable0123a = source0.grow(sink123, Keep.none).connect(source0.outPorts.head, sink123.inPorts.head)
+      val runnable0123b = source012.grow(sink3, Keep.none).connect(source012.outPorts.head, sink3.inPorts.head)
 
       val runnable0123c =
         source0
-          .grow(flow12, ignore).connect(source0.outPorts.head, flow12.inPorts.head)
-          .grow(sink3, ignore).connect(flow12.outPorts.head, sink3.inPorts.head)
+          .grow(flow12, Keep.none).connect(source0.outPorts.head, flow12.inPorts.head)
+          .grow(sink3, Keep.none).connect(flow12.outPorts.head, sink3.inPorts.head)
 
       runnable0123a.inPorts.size should be(0)
       runnable0123a.outPorts.size should be(0)
@@ -113,9 +111,9 @@ class StreamLayoutSpec extends AkkaSpec {
       val stage2 = testStage()
       val sink = testSink()
 
-      val runnable = source.grow(stage1, ignore).connect(source.outPorts.head, stage1.inPorts.head)
-        .grow(stage2, ignore).connect(stage1.outPorts.head, stage2.inPorts.head)
-        .grow(sink, ignore).connect(stage2.outPorts.head, sink.inPorts.head)
+      val runnable = source.grow(stage1, Keep.none).connect(source.outPorts.head, stage1.inPorts.head)
+        .grow(stage2, Keep.none).connect(stage1.outPorts.head, stage2.inPorts.head)
+        .grow(sink, Keep.none).connect(stage2.outPorts.head, sink.inPorts.head)
 
       checkMaterialized(runnable)
     }

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

@@ -25,7 +25,7 @@ class FlowFoldSpec extends AkkaSpec {
 
     "propagate an error" in assertAllStagesStopped {
       val error = new Exception with NoStackTrace
-      val future = Source[Unit](() ⇒ throw error).runFold(())((_, _) ⇒ ())
+      val future = Source[Unit](() ⇒ throw error).runFold(())(Keep.none)
       the[Exception] thrownBy Await.result(future, 3.seconds) should be(error)
     }
 

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

@@ -7,12 +7,16 @@ import akka.japi.function
 import akka.stream.scaladsl
 import akka.japi.Pair
 
+import scala.runtime.BoxedUnit
+
 object Keep {
   private val _left = new function.Function2[Any, Any, Any] with ((Any, Any) ⇒ Any) { def apply(l: Any, r: Any) = l }
   private val _right = new function.Function2[Any, Any, Any] with ((Any, Any) ⇒ Any) { def apply(l: Any, r: Any) = r }
   private val _both = new function.Function2[Any, Any, Any] with ((Any, Any) ⇒ Any) { def apply(l: Any, r: Any) = new akka.japi.Pair(l, r) }
+  private val _none = new function.Function2[Any, Any, Unit] with ((Any, Any) ⇒ Unit) { def apply(l: Any, r: Any) = () }
 
   def left[L, R]: function.Function2[L, R, L] = _left.asInstanceOf[function.Function2[L, R, L]]
   def right[L, R]: function.Function2[L, R, R] = _right.asInstanceOf[function.Function2[L, R, R]]
   def both[L, R]: function.Function2[L, R, L Pair R] = _both.asInstanceOf[function.Function2[L, R, L Pair R]]
+  def none[L, R]: function.Function2[L, R, Unit] = _none.asInstanceOf[function.Function2[L, R, Unit]]
 }

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

@@ -13,8 +13,10 @@ object Keep {
   private val _left = (l: Any, r: Any) ⇒ l
   private val _right = (l: Any, r: Any) ⇒ r
   private val _both = (l: Any, r: Any) ⇒ (l, r)
+  private val _none = (l: Any, r: Any) ⇒ ()
 
   def left[L, R]: (L, R) ⇒ L = _left.asInstanceOf[(L, R) ⇒ L]
   def right[L, R]: (L, R) ⇒ R = _right.asInstanceOf[(L, R) ⇒ R]
   def both[L, R]: (L, R) ⇒ (L, R) = _both.asInstanceOf[(L, R) ⇒ (L, R)]
+  def none[L, R]: (L, R) ⇒ Unit = _none.asInstanceOf[(L, R) ⇒ Unit]
 }