Fix ReceiveTimeout issue with NotInfluenceReceiveTimeout #24770

akka-actor-tests/src/test/scala/akka/actor/ReceiveTimeoutSpec.scala

@@ -113,5 +113,23 @@ class ReceiveTimeoutSpec extends AkkaSpec {
       ticks.cancel()
       system.stop(timeoutActor)
     }
+
+    "get timeout while receiving only NotInfluenceReceiveTimeout messages" taggedAs TimingTest in {
+      val timeoutLatch = TestLatch(2)
+
+      val timeoutActor = system.actorOf(Props(new Actor {
+        context.setReceiveTimeout(1 second)
+
+        def receive = {
+          case ReceiveTimeout ⇒
+            self ! TransperentTick
+            timeoutLatch.countDown()
+          case TransperentTick ⇒
+        }
+      }))
+
+      Await.ready(timeoutLatch, TestLatch.DefaultTimeout)
+      system.stop(timeoutActor)
+    }
   }
 }

akka-actor/src/main/scala/akka/actor/dungeon/ReceiveTimeout.scala

@@ -26,16 +26,13 @@ private[akka] trait ReceiveTimeout { this: ActorCell ⇒
 
   final def checkReceiveTimeout() {
     val recvtimeout = receiveTimeoutData
-    //Only reschedule if desired and there are currently no more messages to be processed
+    recvtimeout._1 match {
-    if (!mailbox.hasMessages) recvtimeout._1 match {
       case f: FiniteDuration ⇒
         recvtimeout._2.cancel() //Cancel any ongoing future
         val task = system.scheduler.scheduleOnce(f, self, akka.actor.ReceiveTimeout)(this.dispatcher)
         receiveTimeoutData = (f, task)
       case _ ⇒ cancelReceiveTimeout()
     }
-    else cancelReceiveTimeout()
-
   }
 
   override final def cancelReceiveTimeout(): Unit =