YARN-11141. Capacity Scheduler does not support ambiguous queue names when moving application across queues. Contributed by Andras Gyori

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/CapacityScheduler.java

@@ -2531,7 +2531,12 @@ public class CapacityScheduler extends
       if (application == null) {
         throw new YarnException("App to be moved " + appId + " not found.");
       }
-      String sourceQueueName = application.getQueue().getQueueName();
+      if (!(application.getQueue() instanceof CSQueue)) {
+        throw new YarnException("Source queue is not a Capacity Scheduler queue");
+      }
+
+      CSQueue csQueue = (CSQueue) application.getQueue();
+      String sourceQueueName = csQueue.getQueuePath();
       LeafQueue source =
           this.queueManager.getAndCheckLeafQueue(sourceQueueName);
       String destQueueName = handleMoveToPlanQueue(targetQueueName);