include initialAttributes of GraphStage, #22463

* these must also be included via setAttributes because
  because it will create island for async (dispatcher attribute)
* better actor name of GraphStageIsland, we need it in tests for
  lookup of the actor
* this unlocks OutputStreamSourceSpec and InputStreamSinkSpec

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

@@ -24,6 +24,9 @@ import org.reactivestreams.{ Processor, Publisher, Subscriber, Subscription }
 import scala.collection.immutable.Map
 import scala.concurrent.duration.FiniteDuration
 import scala.concurrent.ExecutionContextExecutor
+import scala.annotation.tailrec
+import akka.stream.impl.fusing.GraphInterpreter.DownstreamBoundaryStageLogic
+import akka.stream.impl.fusing.GraphInterpreter.UpstreamBoundaryStageLogic
 
 object PhasedFusingActorMaterializer {
 
@@ -656,11 +659,23 @@ final class GraphStageIsland(
       case _ ⇒
         val props = ActorGraphInterpreter.props(shell)
           .withDispatcher(effectiveSettings.dispatcher)
-
-        materializer.actorOf(props, islandName)
+        materializer.actorOf(props, fullIslandName)
     }
   }
 
+  private def fullIslandName: String = {
+    @tailrec def findUsefulName(i: Int): String = {
+      if (i == logics.size) islandName
+      else logics.get(i) match {
+        case _: DownstreamBoundaryStageLogic[_] | _: UpstreamBoundaryStageLogic[_] ⇒
+          findUsefulName(i + 1)
+        case _ ⇒
+          islandName + "-" + logics.get(i).attributes.nameOrDefault()
+      }
+    }
+    findUsefulName(0)
+  }
+
   override def toString: String = "GraphStagePhase"
 }
 
@@ -714,8 +729,8 @@ final class SinkModulePhase(materializer: PhasedFusingActorMaterializer, islandN
 
   override def takePublisher(slot: Int, publisher: Publisher[Any]): Unit = {
     subscriberOrVirtualPublisher match {
-      case v: VirtualPublisher[Any] ⇒ v.registerPublisher(publisher)
-      case s: Subscriber[Any]       ⇒ publisher.subscribe(s)
+      case v: VirtualPublisher[_]        ⇒ v.registerPublisher(publisher)
+      case s: Subscriber[Any] @unchecked ⇒ publisher.subscribe(s)
     }
   }
 

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

@@ -357,5 +357,5 @@ final case class ProcessorModule[In, Out, Mat](
   override def toString: String = f"ProcessorModule [${System.identityHashCode(this)}%08x]"
 
   override private[stream] def traversalBuilder =
-    LinearTraversalBuilder.fromModule(this).makeIsland(ProcessorModuleIslandTag)
+    LinearTraversalBuilder.fromModule(this, attributes).makeIsland(ProcessorModuleIslandTag)
 }

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

@@ -156,23 +156,26 @@ object TraversalBuilder {
   /**
    * Create a generic traversal builder starting from an atomic module.
    */
-  def atomic(module: AtomicModule[Shape, Any], attributes: Attributes = Attributes.none): TraversalBuilder = {
+  def atomic(module: AtomicModule[Shape, Any], attributes: Attributes): TraversalBuilder = {
     initShape(module.shape)
 
+    val builder =
       if (module.shape.outlets.isEmpty) {
         val b = CompletedTraversalBuilder(
           traversalSoFar = MaterializeAtomic(module, Array.ofDim[Int](module.shape.outlets.size)),
           inSlots = module.shape.inlets.size,
           inToOffset = module.shape.inlets.map(in ⇒ in → in.id).toMap,
-        attributes)
+          Attributes.none)
         b
       } else {
         AtomicTraversalBuilder(
           module,
           Array.ofDim[Int](module.shape.outlets.size),
           module.shape.outlets.size,
-        attributes)
+          Attributes.none)
       }
+    // important to use setAttributes because it will create island for async (dispatcher attribute)
+    builder.setAttributes(attributes)
   }
 
   def printTraversal(t: Traversal, indent: Int = 0): Unit = {
@@ -477,7 +480,7 @@ object LinearTraversalBuilder {
    * Create a traversal builder specialized for linear graphs. This is designed to be much faster and lightweight
    * than its generic counterpart. It can be freely mixed with the generic builder in both ways.
    */
-  def fromModule(module: AtomicModule[Shape, Any], attributes: Attributes = Attributes.none): LinearTraversalBuilder = {
+  def fromModule(module: AtomicModule[Shape, Any], attributes: Attributes): LinearTraversalBuilder = {
     require(module.shape.inlets.size <= 1, "Modules with more than one input port cannot be linear.")
     require(module.shape.outlets.size <= 1, "Modules with more than one input port cannot be linear.")
     TraversalBuilder.initShape(module.shape)

akka-stream/src/main/scala/akka/stream/impl/fusing/GraphStages.scala

@@ -36,7 +36,7 @@ final case class GraphStageModule[+S <: Shape @uncheckedVariance, +M](
     if (attributes ne this.attributes) new GraphStageModule(shape, attributes, stage)
     else this
 
-  override private[stream] def traversalBuilder = LinearTraversalBuilder.fromModule(this)
+  override private[stream] def traversalBuilder = LinearTraversalBuilder.fromModule(this, attributes)
 
   override def toString: String = f"GraphStage($stage) [${System.identityHashCode(this)}%08x]"
 }

akka-stream/src/main/scala/akka/stream/impl/io/TlsModule.scala

@@ -28,7 +28,7 @@ private[stream] final case class TlsModule(plainIn: Inlet[SslTlsOutbound], plain
 
   override def toString: String = f"TlsModule($closing) [${System.identityHashCode(this)}%08x]"
 
-  override private[stream] def traversalBuilder = TraversalBuilder.atomic(this).makeIsland(TlsModuleIslandTag)
+  override private[stream] def traversalBuilder = TraversalBuilder.atomic(this, attributes).makeIsland(TlsModuleIslandTag)
 }
 
 /**

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

@@ -30,8 +30,7 @@ import scala.compat.java8.FutureConverters._
  */
 final class Source[+Out, +Mat](
   override val traversalBuilder: LinearTraversalBuilder,
-  override val shape:            SourceShape[Out]
-)
+  override val shape:            SourceShape[Out])
   extends FlowOpsMat[Out, Mat] with Graph[SourceShape[Out], Mat] {
 
   override type Repr[+O] = Source[O, Mat @uncheckedVariance]
@@ -53,8 +52,7 @@ final class Source[+Out, +Mat](
 
     new Source[T, Mat3](
       traversalBuilder.append(toAppend, flow.shape, combine),
-      SourceShape(flow.shape.out)
-    )
+      SourceShape(flow.shape.out))
   }
 
   /**
@@ -157,8 +155,7 @@ final class Source[+Out, +Mat](
    */
   override def async: Repr[Out] = new Source(
     traversalBuilder.makeIsland(GraphStageTag),
-    shape
-  )
+    shape)
 
   /**
    * Converts this Scala DSL element to it's Java DSL counterpart.

akka-stream/src/main/scala/akka/stream/stage/GraphStage.scala

@@ -28,7 +28,10 @@ abstract class GraphStageWithMaterializedValue[+S <: Shape, +M] extends Graph[S,
 
   protected def initialAttributes: Attributes = Attributes.none
 
-  final override lazy val traversalBuilder: TraversalBuilder = TraversalBuilder.atomic(GraphStageModule(shape, initialAttributes, this))
+  final override lazy val traversalBuilder: TraversalBuilder = {
+    val attr = initialAttributes
+    TraversalBuilder.atomic(GraphStageModule(shape, attr, this), attr)
+  }
 
   final override def withAttributes(attr: Attributes): Graph[S, M] = new Graph[S, M] {
     override def shape = GraphStageWithMaterializedValue.this.shape