Closes #3838. Review by prokopec.

git-svn-id: http://lampsvn.epfl.ch/svn-repos/scala/scala/trunk@24466 5e8d7ff9-d8ef-0310-90f0-a4852d11357a

Author: phaller

src/actors/scala/actors/Actor.scala

@@ -589,18 +589,21 @@ trait Actor extends AbstractActor with ReplyReactor with ActorCanReply with Inpu
             done = true
             receiveTimeout
           } else {
-            waitingFor = f
-            received = None
-            isSuspended = true
-            val thisActor = this
-            onTimeout = Some(new TimerTask {
-              def run() { thisActor.send(TIMEOUT, thisActor) }
-            })
-            Actor.timer.schedule(onTimeout.get, msec)
-            scheduler.managedBlock(blocker)
-            drainSendBuffer(mailbox)
-            // keep going
-            () => {}
+            if (onTimeout.isEmpty) {
+              waitingFor = f
+              received = None
+              isSuspended = true
+              val thisActor = this
+              onTimeout = Some(new TimerTask {
+                def run() { thisActor.send(TIMEOUT, thisActor) }
+              })
+              Actor.timer.schedule(onTimeout.get, msec)
+              scheduler.managedBlock(blocker)
+              drainSendBuffer(mailbox)
+              // keep going
+              () => {}
+            } else
+              sys.error("unhandled timeout")
           }
         }
         todo()

test/files/jvm/t3838.check

@@ -0,0 +1 @@
+caught java.lang.RuntimeException: unhandled timeout

test/files/jvm/t3838.scala

@@ -0,0 +1,15 @@
+import scala.actors.Actor._
+
+object Test {
+  def main(args: Array[String]) {
+    actor {
+      try {
+        receiveWithin(1) {
+          case str: String => println(str)
+        }
+      } catch {
+        case e: Exception => println("caught "+e)
+      }
+    }
+  }
+}