Extends collection of shutdown Reasons (e.g. ClusterJoinUnsuccessfulReason) (#26570)

* Adds JoiningSeedNodesUnsuccessfulReason

* Promotes IncompatibleConfigurationDetectedReason to public API

* Rename class after PR comments

* Use a custom exit code on joinUnsuccesful shuhtdown

* Mima

* Scalafmt

akka-actor/src/main/resources/reference.conf

@@ -1115,13 +1115,15 @@ akka {
     # Only 'exit-jvm', 'exit-code' and 'terminate-actor-system' may be
     # overridden depending on the reason.
     reason-overrides {
-      # Overrides are applied using the `reason.getClass.getName`. This
-      # default overrides the `exit-code` when the `Reason` is a cluster
-      # Downing event (identified by the object
-      # "akka.actor.CoordinatedShutdown$ClusterDowningReason$").
+      # Overrides are applied using the `reason.getClass.getName`.
+      # Overrides the `exit-code` when the `Reason` is a cluster
+      # Downing or a Cluster Join Unsuccessful event
       "akka.actor.CoordinatedShutdown$ClusterDowningReason$" {
         exit-code = -1
       }
+      "akka.actor.CoordinatedShutdown$ClusterJoinUnsuccessfulReason$" {
+        exit-code = -1
+      }
     }
 
     #//#coordinated-shutdown-phases

akka-actor/src/main/scala/akka/actor/CoordinatedShutdown.scala

@@ -140,6 +140,26 @@ object CoordinatedShutdown extends ExtensionId[CoordinatedShutdown] with Extensi
    */
   def clusterDowningReason: Reason = ClusterDowningReason
 
+  /**
+   * Scala API: The shutdown was initiated by a failure to join a seed node.
+   */
+  object ClusterJoinUnsuccessfulReason extends Reason
+
+  /**
+   * Java API: The shutdown was initiated by a failure to join a seed node.
+   */
+  def clusterJoinUnsuccessfulReason: Reason = ClusterJoinUnsuccessfulReason
+
+  /**
+   * Scala API: The shutdown was initiated by a configuration clash within the existing cluster and the joining node
+   */
+  case object IncompatibleConfigurationDetectedReason extends Reason
+
+  /**
+   * Java API: The shutdown was initiated by a configuration clash within the existing cluster and the joining node
+   */
+  def incompatibleConfigurationDetectedReason: Reason = IncompatibleConfigurationDetectedReason
+
   /**
    * Scala API: The shutdown was initiated by Cluster leaving.
    */

akka-cluster/src/main/mima-filters/2.5.21.backwards.excludes

@@ -0,0 +1,3 @@
+# #26570 Promote IncompatibleConfigurationDetected to public API (moved package and made public)
+ProblemFilters.exclude[MissingClassProblem]("akka.cluster.IncompatibleConfigurationDetected")
+ProblemFilters.exclude[MissingClassProblem]("akka.cluster.IncompatibleConfigurationDetected$")

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

@@ -501,7 +501,7 @@ private[cluster] class ClusterCoreDaemon(publisher: ActorRef, joinConfigCompatCh
       seedNodes.mkString(", "),
       ShutdownAfterUnsuccessfulJoinSeedNodes)
     joinSeedNodesDeadline = None
-    CoordinatedShutdown(context.system).run(CoordinatedShutdown.ClusterDowningReason)
+    CoordinatedShutdown(context.system).run(CoordinatedShutdown.ClusterJoinUnsuccessfulReason)
   }
 
   def becomeUninitialized(): Unit = {
@@ -1477,11 +1477,6 @@ private[cluster] class ClusterCoreDaemon(publisher: ActorRef, joinConfigCompatCh
 
 }
 
-/**
- * INTERNAL API.
- */
-private[cluster] case object IncompatibleConfigurationDetected extends Reason
-
 /**
  * INTERNAL API.
  *
@@ -1569,7 +1564,7 @@ private[cluster] final class FirstSeedNodeProcess(
             "This node will be shutdown!",
             messages.mkString(", "))
           context.stop(self)
-          CoordinatedShutdown(context.system).run(IncompatibleConfigurationDetected)
+          CoordinatedShutdown(context.system).run(CoordinatedShutdown.IncompatibleConfigurationDetectedReason)
       }
 
     case InitJoinAck(address, UncheckedConfig) =>
@@ -1597,7 +1592,7 @@ private[cluster] final class FirstSeedNodeProcess(
           "Note that disabling it will allow the formation of a cluster with nodes having incompatible configuration settings. " +
           "This node will be shutdown!")
         context.stop(self)
-        CoordinatedShutdown(context.system).run(IncompatibleConfigurationDetected)
+        CoordinatedShutdown(context.system).run(CoordinatedShutdown.IncompatibleConfigurationDetectedReason)
       }
 
     case InitJoinNack(address) =>
@@ -1701,7 +1696,7 @@ private[cluster] final class JoinSeedNodeProcess(
             "This node will be shutdown!",
             messages.mkString(", "))
           context.stop(self)
-          CoordinatedShutdown(context.system).run(IncompatibleConfigurationDetected)
+          CoordinatedShutdown(context.system).run(CoordinatedShutdown.IncompatibleConfigurationDetectedReason)
       }
 
     case InitJoinAck(address, UncheckedConfig) =>
@@ -1728,7 +1723,7 @@ private[cluster] final class JoinSeedNodeProcess(
           "Note that disabling it will allow the formation of a cluster with nodes having incompatible configuration settings. " +
           "This node will be shutdown!")
         context.stop(self)
-        CoordinatedShutdown(context.system).run(IncompatibleConfigurationDetected)
+        CoordinatedShutdown(context.system).run(CoordinatedShutdown.IncompatibleConfigurationDetectedReason)
       }
 
     case InitJoinNack(_) => // that seed was uninitialized