SCBC-495: cluster.disconnect() is intermittently not blocking until all components are ended

The root cause here was that disconnect was shutting down
a threadpool, and accidentally doing that work on a thread
that was itself on the same threadpool.

Change-Id: I3c95df82cc23f346799032dba6596af4e0ecaa51
Reviewed-on: https://review.couchbase.org/c/couchbase-jvm-clients/+/234779
Reviewed-by: David Nault <[email protected]>
Tested-by: Build Bot <[email protected]>

Author: programmatix

scala-client/src/main/scala-2/com/couchbase/client/scala/AsyncCluster.scala

@@ -308,7 +308,14 @@ class AsyncCluster(
   def disconnect(timeout: Duration = env.timeoutConfig.disconnectTimeout()): Future[Unit] = {
     FutureConversions
       .javaMonoToScalaFuture(couchbaseOps.shutdown(timeout))
-      .map(_ => if (env.owned) env.shutdown(timeout))
+      .flatMap(_ =>
+        if (env.owned) {
+          // Explicitly put this on the global threadpool, otherwise it will execute on the
+          // threadpool we are shutting down due to the implicit `ec` in scope.
+          Future(env.shutdown(timeout))(scala.concurrent.ExecutionContext.global)
+        } else
+          Future.successful(())
+      )
   }
 
   /** Returns a `DiagnosticsResult`, reflecting the SDK's current view of all its existing connections to the

scala-client/src/test/scala/com/couchbase/client/scala/EnvironmentSpec.scala

@@ -2,7 +2,7 @@ package com.couchbase.client.scala
 
 import com.couchbase.client.core.env.WanDevelopmentProfile
 import com.couchbase.client.scala.env._
-import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.{RepeatedTest, Test}
 
 import scala.concurrent.duration.{Duration, _}
 import scala.util.{Success, Try}
@@ -144,7 +144,8 @@ class EnvironmentSpec {
     }
   }
 
-  @Test
+  // Repeated as this has been an intermittent failure in the past
+  @RepeatedTest(10)
   def closeOwnedEnvironment(): Unit = {
     val clusterTry: Try[Cluster] = Cluster.connect("1.2.3.4", "username", "password")