HBASE-28928 Handle NPE in Split/Merge table when getMasterQuotaManager returns null (#6375) (#6393)

Signed-off-by: Nihal Jain <nihaljain@apache.org>

Author: mnpoonia

hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/MergeTableRegionsProcedure.java

@@ -51,6 +51,7 @@
 import org.apache.hadoop.hbase.master.procedure.MasterProcedureUtil;
 import org.apache.hadoop.hbase.procedure2.ProcedureMetrics;
 import org.apache.hadoop.hbase.procedure2.ProcedureStateSerializer;
+import org.apache.hadoop.hbase.quotas.MasterQuotaManager;
 import org.apache.hadoop.hbase.quotas.QuotaExceededException;
 import org.apache.hadoop.hbase.regionserver.HRegionFileSystem;
 import org.apache.hadoop.hbase.regionserver.HStoreFile;
@@ -540,7 +541,10 @@ private void preMergeRegions(final MasterProcedureEnv env) throws IOException {
     }
     // TODO: Clean up split and merge. Currently all over the place.
     try {
-      env.getMasterServices().getMasterQuotaManager().onRegionMerged(this.mergedRegion);
+      MasterQuotaManager masterQuotaManager = env.getMasterServices().getMasterQuotaManager();
+      if (masterQuotaManager != null) {
+        masterQuotaManager.onRegionMerged(this.mergedRegion);
+      }
     } catch (QuotaExceededException e) {
       // TODO: why is this here? merge requests can be submitted by actors other than the normalizer
       env.getMasterServices().getRegionNormalizerManager()

hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/SplitTableRegionProcedure.java

@@ -57,6 +57,7 @@
 import org.apache.hadoop.hbase.master.procedure.MasterProcedureUtil;
 import org.apache.hadoop.hbase.procedure2.ProcedureMetrics;
 import org.apache.hadoop.hbase.procedure2.ProcedureStateSerializer;
+import org.apache.hadoop.hbase.quotas.MasterQuotaManager;
 import org.apache.hadoop.hbase.quotas.QuotaExceededException;
 import org.apache.hadoop.hbase.regionserver.HRegionFileSystem;
 import org.apache.hadoop.hbase.regionserver.HStore;
@@ -601,7 +602,10 @@ private void preSplitRegion(final MasterProcedureEnv env)
     // TODO: Clean up split and merge. Currently all over the place.
     // Notify QuotaManager and RegionNormalizer
     try {
-      env.getMasterServices().getMasterQuotaManager().onRegionSplit(this.getParentRegion());
+      MasterQuotaManager masterQuotaManager = env.getMasterServices().getMasterQuotaManager();
+      if (masterQuotaManager != null) {
+        masterQuotaManager.onRegionSplit(this.getParentRegion());
+      }
     } catch (QuotaExceededException e) {
       // TODO: why is this here? split requests can be submitted by actors other than the normalizer
       env.getMasterServices().getRegionNormalizerManager()