From 8a3cf8145b12adc5345ccbfbeca2f1b1d682209a Mon Sep 17 00:00:00 2001
From: Roland Kuhn <rk@rkuhn.info>
Date: Fri, 18 Mar 2016 12:28:27 +0100
Subject: [PATCH] lift mapMaterializedValue to FlowOpsMat

---
 akka-stream/src/main/scala/akka/stream/scaladsl/Flow.scala | 7 ++++++-
 .../src/main/scala/akka/stream/scaladsl/Source.scala       | 4 ++--
 project/MiMa.scala                                         | 3 +++
 3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/akka-stream/src/main/scala/akka/stream/scaladsl/Flow.scala b/akka-stream/src/main/scala/akka/stream/scaladsl/Flow.scala
index e041eaa743..755da1ebe6 100644
--- a/akka-stream/src/main/scala/akka/stream/scaladsl/Flow.scala
+++ b/akka-stream/src/main/scala/akka/stream/scaladsl/Flow.scala
@@ -114,7 +114,7 @@ final class Flow[-In, +Out, +Mat](private[stream] override val module: Module)
   /**
    * Transform the materialized value of this Flow, leaving all other properties as they were.
    */
-  def mapMaterializedValue[Mat2](f: Mat ⇒ Mat2): ReprMat[Out, Mat2] =
+  override def mapMaterializedValue[Mat2](f: Mat ⇒ Mat2): ReprMat[Out, Mat2] =
     new Flow(module.transformMaterializedValue(f.asInstanceOf[Any ⇒ Any]))
 
   /**
@@ -1983,6 +1983,11 @@ trait FlowOpsMat[+Out, +Mat] extends FlowOps[Out, Mat] {
   def watchTermination[Mat2]()(matF: (Mat, Future[Done]) ⇒ Mat2): ReprMat[Out, Mat2] =
     viaMat(GraphStages.terminationWatcher)(matF)
 
+  /**
+   * Transform the materialized value of this graph, leaving all other properties as they were.
+   */
+  def mapMaterializedValue[Mat2](f: Mat ⇒ Mat2): ReprMat[Out, Mat2]
+
   /**
    * INTERNAL API.
    */
diff --git a/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala b/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala
index 7740e27fd6..0d6a7ec994 100644
--- a/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala
+++ b/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala
@@ -28,7 +28,7 @@ import scala.compat.java8.FutureConverters._
  * a Reactive Streams `Publisher` (at least conceptually).
  */
 final class Source[+Out, +Mat](private[stream] override val module: Module)
-  extends FlowOpsMat[Out, Mat] with Graph[SourceShape[Out], Mat] {
+    extends FlowOpsMat[Out, Mat] with Graph[SourceShape[Out], Mat] {
 
   override type Repr[+O] = Source[O, Mat @uncheckedVariance]
   override type ReprMat[+O, +M] = Source[O, M]
@@ -71,7 +71,7 @@ final class Source[+Out, +Mat](private[stream] override val module: Module)
   /**
    * Transform only the materialized value of this Source, leaving all other properties as they were.
    */
-  def mapMaterializedValue[Mat2](f: Mat ⇒ Mat2): ReprMat[Out, Mat2] =
+  override def mapMaterializedValue[Mat2](f: Mat ⇒ Mat2): ReprMat[Out, Mat2] =
     new Source[Out, Mat2](module.transformMaterializedValue(f.asInstanceOf[Any ⇒ Any]))
 
   /** INTERNAL API */
diff --git a/project/MiMa.scala b/project/MiMa.scala
index 2af118b654..aececeaed8 100644
--- a/project/MiMa.scala
+++ b/project/MiMa.scala
@@ -659,6 +659,9 @@ object MiMa extends AutoPlugin {
         ProblemFilters.exclude[DirectMissingMethodProblem]("akka.stream.impl.fusing.Drop.onPush"),
         ProblemFilters.exclude[FinalClassProblem]("akka.stream.stage.GraphStageLogic$Reading"), // this class is private
 
+        // lifting this method to the type where it belongs
+        ProblemFilters.exclude[ReversedMissingMethodProblem]("akka.stream.scaladsl.FlowOpsMat.mapMaterializedValue"),
+
         // #19908 Take is private
         ProblemFilters.exclude[MissingClassProblem]("akka.stream.impl.Stages$Take$"),
         ProblemFilters.exclude[MissingClassProblem]("akka.stream.impl.Stages$Take"),