From cbf390422b988b0fd4466c36bc8e4c767903e63c Mon Sep 17 00:00:00 2001
From: Andrew Purtell <apurtell@apache.org>
Date: Wed, 19 Jul 2017 15:46:08 -0700
Subject: [PATCH] HBASE-18330 NPE in ReplicationZKLockCleanerChore

---
 .../hadoop/hbase/replication/ReplicationPeersZKImpl.java       | 3 +++
 .../hbase/replication/ReplicationQueuesClientZKImpl.java       | 2 +-
 .../hadoop/hbase/master/cleaner/ReplicationZKNodeCleaner.java  | 3 +++
 .../hbase/replication/regionserver/DumpReplicationQueues.java  | 3 +++
 4 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/replication/ReplicationPeersZKImpl.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/replication/ReplicationPeersZKImpl.java
index 02fe2f13b1a..751e45441f8 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/replication/ReplicationPeersZKImpl.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/replication/ReplicationPeersZKImpl.java
@@ -520,6 +520,9 @@ public class ReplicationPeersZKImpl extends ReplicationStateZKBase implements Re
     if (queuesClient == null) return;
     try {
       List<String> replicators = queuesClient.getListOfReplicators();
+      if (replicators == null || replicators.isEmpty()) {
+        return;
+      }
       for (String replicator : replicators) {
         List<String> queueIds = queuesClient.getAllQueues(replicator);
         for (String queueId : queueIds) {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/replication/ReplicationQueuesClientZKImpl.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/replication/ReplicationQueuesClientZKImpl.java
index 050437353e0..0115b6f8127 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/replication/ReplicationQueuesClientZKImpl.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/replication/ReplicationQueuesClientZKImpl.java
@@ -98,7 +98,7 @@ public class ReplicationQueuesClientZKImpl extends ReplicationStateZKBase implem
     for (int retry = 0; ; retry++) {
       int v0 = getQueuesZNodeCversion();
       List<String> rss = getListOfReplicators();
-      if (rss == null) {
+      if (rss == null || rss.isEmpty()) {
         LOG.debug("Didn't find any region server that replicates, won't prevent any deletions.");
         return ImmutableSet.of();
       }
diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/cleaner/ReplicationZKNodeCleaner.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/cleaner/ReplicationZKNodeCleaner.java
index dafc4f8f820..6d8962e9234 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/cleaner/ReplicationZKNodeCleaner.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/cleaner/ReplicationZKNodeCleaner.java
@@ -77,6 +77,9 @@ public class ReplicationZKNodeCleaner {
     Set<String> peerIds = new HashSet<>(this.replicationPeers.getAllPeerIds());
     try {
       List<String> replicators = this.queuesClient.getListOfReplicators();
+      if (replicators == null || replicators.isEmpty()) {
+        return undeletedQueues;
+      }
       for (String replicator : replicators) {
         List<String> queueIds = this.queuesClient.getAllQueues(replicator);
         for (String queueId : queueIds) {
diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/DumpReplicationQueues.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/DumpReplicationQueues.java
index 2bedbfd17b9..4bda75be366 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/DumpReplicationQueues.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/DumpReplicationQueues.java
@@ -323,6 +323,9 @@ public class DumpReplicationQueues extends Configured implements Tool {
     // Loops each peer on each RS and dumps the queues
     try {
       List<String> regionservers = queuesClient.getListOfReplicators();
+      if (regionservers == null || regionservers.isEmpty()) {
+        return sb.toString();
+      }
       for (String regionserver : regionservers) {
         List<String> queueIds = queuesClient.getAllQueues(regionserver);
         replicationQueues.init(regionserver);