From 7ba40b238ab6a400269349ffe022ae080c5c28a8 Mon Sep 17 00:00:00 2001
From: pwliwanow <pwliwanow@users.noreply.github.com>
Date: Mon, 29 Jan 2018 12:05:28 +0100
Subject: [PATCH] Fix in BackoffSupervisor.calculateDelay #24419

---
 .../akka/pattern/BackoffSupervisorSpec.scala  | 28 +++++++++++++++++--
 .../akka/pattern/BackoffSupervisor.scala      | 16 +++++------
 2 files changed, 34 insertions(+), 10 deletions(-)

diff --git a/akka-actor-tests/src/test/scala/akka/pattern/BackoffSupervisorSpec.scala b/akka-actor-tests/src/test/scala/akka/pattern/BackoffSupervisorSpec.scala
index cc6aab7a95..05f9570494 100644
--- a/akka-actor-tests/src/test/scala/akka/pattern/BackoffSupervisorSpec.scala
+++ b/akka-actor-tests/src/test/scala/akka/pattern/BackoffSupervisorSpec.scala
@@ -4,11 +4,12 @@
 
 package akka.pattern
 
-import scala.concurrent.duration._
 import akka.actor._
 import akka.testkit._
+import org.scalatest.prop.TableDrivenPropertyChecks._
+
+import scala.concurrent.duration._
 import scala.util.control.NoStackTrace
-import akka.actor.SupervisorStrategy
 
 object BackoffSupervisorSpec {
 
@@ -218,5 +219,28 @@ class BackoffSupervisorSpec extends AkkaSpec with ImplicitSender {
         expectNoMsg(500.milliseconds)
       }
     }
+
+    "correctly calculate the delay" in {
+      val delayTable =
+        Table(
+          ("restartCount", "minBackoff", "maxBackoff", "randomFactor", "expectedResult"),
+          (0, 0.minutes, 0.minutes, 0d, 0.minutes),
+          (0, 5.minutes, 7.minutes, 0d, 5.minutes),
+          (2, 5.seconds, 7.seconds, 0d, 7.seconds),
+          (2, 5.seconds, 7.days, 0d, 20.seconds),
+          (29, 5.minutes, 10.minutes, 0d, 10.minutes),
+          (29, 10000.days, 10000.days, 0d, 10000.days),
+          (Int.MaxValue, 10000.days, 10000.days, 0d, 10000.days))
+      forAll(delayTable) { (
+        restartCount: Int,
+        minBackoff: FiniteDuration,
+        maxBackoff: FiniteDuration,
+        randomFactor: Double,
+        expectedResult: FiniteDuration) ⇒
+
+        val calculatedValue = BackoffSupervisor.calculateDelay(restartCount, minBackoff, maxBackoff, randomFactor)
+        assert(calculatedValue === expectedResult)
+      }
+    }
   }
 }
diff --git a/akka-actor/src/main/scala/akka/pattern/BackoffSupervisor.scala b/akka-actor/src/main/scala/akka/pattern/BackoffSupervisor.scala
index a173ac08fd..75e1e4470b 100644
--- a/akka-actor/src/main/scala/akka/pattern/BackoffSupervisor.scala
+++ b/akka-actor/src/main/scala/akka/pattern/BackoffSupervisor.scala
@@ -3,7 +3,6 @@
  */
 package akka.pattern
 
-import scala.concurrent.duration.{ Duration, FiniteDuration }
 import java.util.concurrent.ThreadLocalRandom
 import java.util.Optional
 
@@ -17,6 +16,9 @@ import akka.actor.SupervisorStrategy.Escalate
 import akka.actor.OneForOneStrategy
 import akka.actor.SupervisorStrategy
 
+import scala.concurrent.duration.{ Duration, FiniteDuration }
+import scala.util.Try
+
 object BackoffSupervisor {
 
   /**
@@ -152,13 +154,11 @@ object BackoffSupervisor {
     maxBackoff:   FiniteDuration,
     randomFactor: Double): FiniteDuration = {
     val rnd = 1.0 + ThreadLocalRandom.current().nextDouble() * randomFactor
-    if (restartCount >= 30) // Duration overflow protection (> 100 years)
-      maxBackoff
-    else
-      maxBackoff.min(minBackoff * math.pow(2, restartCount)) * rnd match {
-        case f: FiniteDuration ⇒ f
-        case _                 ⇒ maxBackoff
-      }
+    val calculatedDuration = Try(maxBackoff.min(minBackoff * math.pow(2, restartCount)) * rnd).getOrElse(maxBackoff)
+    calculatedDuration match {
+      case f: FiniteDuration ⇒ f
+      case _                 ⇒ maxBackoff
+    }
   }
 }