fix: Avoid turning all stream timeouts to TcpIdleTimeoutException

akka-stream/src/main/mima-filters/2.9.0.backwards.excludes/tcp-idle-timeout.excludes

@@ -0,0 +1,2 @@
+# Internal API changed
+ProblemFilters.exclude[DirectMissingMethodProblem]("akka.stream.impl.Timers#IdleTimeoutBidi.this")

akka-stream/src/main/scala/akka/stream/StreamTimeoutException.scala

@@ -15,7 +15,7 @@ import akka.annotation.DoNotInherit
  * Not for user extension
  */
 @DoNotInherit
-sealed class StreamTimeoutException(msg: String) extends TimeoutException(msg) with NoStackTrace
+class StreamTimeoutException(msg: String) extends TimeoutException(msg) with NoStackTrace
 
 final class InitialTimeoutException(msg: String) extends StreamTimeoutException(msg)
 

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

@@ -151,7 +151,14 @@ import akka.stream.stage._
 
   }
 
-  final class IdleTimeoutBidi[I, O](val timeout: FiniteDuration) extends GraphStage[BidiShape[I, I, O, O]] {
+  private object IdleTimeoutBidi {
+    val defaultFailureCreator: FiniteDuration => Throwable = timeout =>
+      new StreamIdleTimeoutException(s"No elements passed in the last ${timeout.toCoarsest}.")
+  }
+  final class IdleTimeoutBidi[I, O](
+      val timeout: FiniteDuration,
+      failureCreator: FiniteDuration => Throwable = IdleTimeoutBidi.defaultFailureCreator)
+      extends GraphStage[BidiShape[I, I, O, O]] {
     val in1 = Inlet[I]("in1")
     val in2 = Inlet[O]("in2")
     val out1 = Outlet[I]("out1")
@@ -170,7 +177,7 @@ import akka.stream.stage._
 
       final override def onTimer(key: Any): Unit =
         if (nextDeadline - System.nanoTime < 0)
-          failStage(new StreamIdleTimeoutException(s"No elements passed in the last ${timeout.toCoarsest}."))
+          failStage(failureCreator(timeout))
 
       override def preStart(): Unit =
         scheduleWithFixedDelay(GraphStageLogicTimer, timeoutCheckInterval(timeout), timeoutCheckInterval(timeout))

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

@@ -5,14 +5,11 @@
 package akka.stream.impl.io
 
 import java.net.InetSocketAddress
-import java.util.concurrent.TimeoutException
 import java.util.concurrent.atomic.{ AtomicBoolean, AtomicLong }
-
 import scala.annotation.nowarn
 import scala.collection.immutable
 import scala.concurrent.{ Future, Promise }
 import scala.concurrent.duration.{ Duration, FiniteDuration }
-
 import akka.{ Done, NotUsed }
 import akka.actor.{ ActorRef, Terminated }
 import akka.annotation.InternalApi
@@ -22,6 +19,7 @@ import akka.io.Tcp
 import akka.io.Tcp._
 import akka.stream._
 import akka.stream.impl.ReactiveStreamsCompliance
+import akka.stream.impl.Timers
 import akka.stream.impl.fusing.GraphStages.detacher
 import akka.stream.scaladsl.{ BidiFlow, Flow, TcpIdleTimeoutException, Tcp => StreamTcp }
 import akka.stream.scaladsl.Tcp.{ OutgoingConnection, ServerBinding }
@@ -593,19 +591,13 @@ private[stream] object ConnectionSourceStage {
       case Some(address) => s" on connection to [$address]"
       case _             => ""
     }
+    BidiFlow.fromGraph(
+      new Timers.IdleTimeoutBidi(
+        idleTimeout,
+        failureCreator = _ =>
+          new TcpIdleTimeoutException(
+            s"TCP idle-timeout encountered$connectionToString, no bytes passed in the last $idleTimeout",
+            idleTimeout)))
 
-    val toNetTimeout: BidiFlow[ByteString, ByteString, ByteString, ByteString, NotUsed] =
-      BidiFlow.fromFlows(
-        Flow[ByteString].mapError {
-          case _: TimeoutException =>
-            new TcpIdleTimeoutException(
-              s"TCP idle-timeout encountered$connectionToString, no bytes passed in the last $idleTimeout",
-              idleTimeout)
-        },
-        Flow[ByteString])
-    val fromNetTimeout: BidiFlow[ByteString, ByteString, ByteString, ByteString, NotUsed] =
-      toNetTimeout.reversed // now the bottom flow transforms the exception, the top one doesn't (since that one is "fromNet")
-
-    fromNetTimeout.atop(BidiFlow.bidirectionalIdleTimeout[ByteString, ByteString](idleTimeout)).atop(toNetTimeout)
   }
 }

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

@@ -5,7 +5,6 @@
 package akka.stream.scaladsl
 
 import java.net.InetSocketAddress
-import java.util.concurrent.TimeoutException
 import javax.net.ssl.SSLEngine
 import javax.net.ssl.SSLSession
 
@@ -394,7 +393,7 @@ final class Tcp(system: ExtendedActorSystem) extends akka.actor.Extension {
 }
 
 final class TcpIdleTimeoutException(msg: String, @unused timeout: Duration)
-    extends TimeoutException(msg: String)
+    extends StreamTimeoutException(msg: String)
     with NoStackTrace // only used from a single stage
 
 object TcpAttributes {