Merge pull request #25963 from akka/wip-25950-allObservers-patriknw

Reachability.allObservers wrong after filterRecords, #25950

akka-cluster/src/main/scala/akka/cluster/Gossip.scala

@@ -71,19 +71,31 @@ private[cluster] final case class Gossip(
 
   private def assertInvariants(): Unit = {
 
-    if (members.exists(_.status == Removed))
-      throw new IllegalArgumentException(s"Live members must not have status [${Removed}], " +
-        s"got [${members.filter(_.status == Removed)}]")
+    def ifTrueThrow(func: ⇒ Boolean, expected: String, actual: String): Unit =
+      if (func) throw new IllegalArgumentException(s"$expected, but found [$actual]")
+
+    ifTrueThrow(
+      members.exists(_.status == Removed),
+      expected = s"Live members must not have status [$Removed]",
+      actual = s"${members.filter(_.status == Removed)}")
 
     val inReachabilityButNotMember = overview.reachability.allObservers diff members.map(_.uniqueAddress)
-    if (inReachabilityButNotMember.nonEmpty)
-      throw new IllegalArgumentException("Nodes not part of cluster in reachability table, got [%s]"
-        format inReachabilityButNotMember.mkString(", "))
+    ifTrueThrow(
+      inReachabilityButNotMember.nonEmpty,
+      expected = "Nodes not part of cluster in reachability table",
+      actual = inReachabilityButNotMember.mkString(", "))
+
+    val inReachabilityVersionsButNotMember = overview.reachability.versions.keySet diff members.map(_.uniqueAddress)
+    ifTrueThrow(
+      inReachabilityVersionsButNotMember.nonEmpty,
+      expected = "Nodes not part of cluster in reachability versions table",
+      actual = inReachabilityVersionsButNotMember.mkString(", "))
 
     val seenButNotMember = overview.seen diff members.map(_.uniqueAddress)
-    if (seenButNotMember.nonEmpty)
-      throw new IllegalArgumentException("Nodes not part of cluster have marked the Gossip as seen, got [%s]"
-        format seenButNotMember.mkString(", "))
+    ifTrueThrow(
+      seenButNotMember.nonEmpty,
+      expected = "Nodes not part of cluster have marked the Gossip as seen",
+      actual = seenButNotMember.mkString(", "))
   }
 
   @transient private lazy val membersMap: Map[UniqueAddress, Member] =

akka-cluster/src/main/scala/akka/cluster/Reachability.scala

@@ -276,7 +276,7 @@ private[cluster] class Reachability private (
     }
   }
 
-  def allObservers: Set[UniqueAddress] = versions.keySet
+  def allObservers: Set[UniqueAddress] = records.iterator.map(_.observer).toSet
 
   def recordsFrom(observer: UniqueAddress): immutable.IndexedSeq[Record] = {
     observerRows(observer) match {

akka-cluster/src/test/scala/akka/cluster/ReachabilityPerfSpec.scala

@@ -27,8 +27,8 @@ class ReachabilityPerfSpec extends WordSpec with Matchers {
     }
 
   private def addUnreachable(base: Reachability, count: Int): Reachability = {
-    val observers = base.allObservers.take(count)
-    val subjects = Stream.continually(base.allObservers).flatten.iterator
+    val observers = base.versions.keySet.take(count)
+    val subjects = Stream.continually(base.versions.keySet).flatten.iterator
     observers.foldLeft(base) {
       case (r, o) ⇒
         (1 to 5).foldLeft(r) { case (r, _) ⇒ r.unreachable(o, subjects.next()) }
@@ -38,7 +38,7 @@ class ReachabilityPerfSpec extends WordSpec with Matchers {
   val reachability1 = createReachabilityOfSize(Reachability.empty, nodesSize)
   val reachability2 = createReachabilityOfSize(reachability1, nodesSize)
   val reachability3 = addUnreachable(reachability1, nodesSize / 2)
-  val allowed = reachability1.allObservers
+  val allowed = reachability1.versions.keySet
 
   private def checkThunkFor(r1: Reachability, r2: Reachability, thunk: (Reachability, Reachability) ⇒ Unit, times: Int): Unit = {
     for (i ← 1 to times) {

akka-cluster/src/test/scala/akka/cluster/ReachabilitySpec.scala

@@ -235,5 +235,17 @@ class ReachabilitySpec extends WordSpec with Matchers {
       r2.versions.keySet should ===(Set(nodeD))
     }
 
+    "be able to filter records" in {
+      val r = Reachability.empty
+        .unreachable(nodeC, nodeB)
+        .unreachable(nodeB, nodeA)
+        .unreachable(nodeB, nodeC)
+
+      val filtered1 = r.filterRecords(record ⇒ record.observer != nodeC)
+      filtered1.isReachable(nodeB) should ===(true)
+      filtered1.isReachable(nodeA) should ===(false)
+      filtered1.allObservers should ===(Set(nodeB))
+    }
+
   }
 }