Fixes akkadotnet#996

src/core/Akka.Tests/Routing/RoutingSpec.cs

@@ -289,6 +289,47 @@ public void Router_RemoveRoute_should_remove_existing_routee_and_leave_the_rest(
             updatedRouter.Routees.Cast<ActorRefRoutee>().Any(r => ReferenceEquals(r.Actor, blackHole1)).ShouldBe(true);
             updatedRouter.Routees.Cast<ActorRefRoutee>().Any(r => ReferenceEquals(r.Actor, blackHole2)).ShouldBe(true);
         }
+
+        public class RouterSupervisorSpec : AkkaSpec
+        {
+            #region Killable actor
+
+            private class KillableActor : ReceiveActor
+            {
+                private readonly IActorRef TestActor;
+
+                public KillableActor(IActorRef testActor)
+                {
+                    TestActor = testActor;
+                    Receive<string>(s => s == "go away", s => { throw new ArgumentException("Goodbye then!"); });
+                }
+            }
+
+            #endregion
+
+            #region Tests
+
+            [Fact]
+            public void Routers_must_use_provided_supervisor_strategy()
+            {
+                var router = Sys.ActorOf(Props.Create(() => new KillableActor(TestActor))
+                    .WithRouter(
+                        new RoundRobinPool(1, null, new AllForOneStrategy(
+                            exception =>
+                            {
+                                TestActor.Tell("supervised");
+                                return Directive.Stop;
+                            }),
+                            null)),
+                    "router1");
+
+                router.Tell("go away");
+
+                ExpectMsg("supervised", TimeSpan.FromSeconds(2));
+            }
+
+            #endregion
+        }
     }
 }
 

src/core/Akka/Actor/ActorCell.cs

@@ -209,6 +209,8 @@ private ActorBase NewActor()
             {
                 _state = _state.ClearBehaviorStack();
                 instance = CreateNewActorInstance();
+                //TODO: this overwrites any already initiaized supervisor strategy
+                //We should investigate what we can do to handle this better
                 instance.SupervisorStrategyInternal = _props.SupervisorStrategy;
                 //defaults to null - won't affect lazy instantiation unless explicitly set in props
             });

src/core/Akka/Routing/RouterPoolActor.cs

@@ -18,7 +18,7 @@ namespace Akka.Routing
     /// </summary>
     internal class RouterPoolActor : RouterActor
     {
-   //     private SupervisorStrategy supervisorStrategy;
+        private readonly SupervisorStrategy _supervisorStrategy;
 
         protected Pool Pool
         {
@@ -42,7 +42,12 @@ protected Pool Pool
         /// <param name="supervisorStrategy">The supervisor strategy.</param>
         public RouterPoolActor(SupervisorStrategy supervisorStrategy)
         {
-            SupervisorStrategyInternal = supervisorStrategy;
+            _supervisorStrategy = supervisorStrategy;
+        }
+
+        protected override SupervisorStrategy SupervisorStrategy()
+        {
+            return _supervisorStrategy;
         }
 
         /// <summary>