HBASE-23119 ArrayIndexOutOfBoundsException in PrivateCellUtil#qualifi…

…erStartsWith (#688)

Signed-off-by: Peter Somogyi <psomogyi@apache.org>
Signed-off-by: Viraj Jasani <virajjasani007@gmail.com>

hbase-client/src/test/java/org/apache/hadoop/hbase/filter/TestComparators.java

@@ -18,6 +18,7 @@
 package org.apache.hadoop.hbase.filter;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
 import java.nio.ByteBuffer;
@@ -97,5 +98,12 @@ public void testCellFieldsCompare() throws Exception {
     comparable = new SubstringComparator("cf");
     assertEquals(0, PrivateCellUtil.compareFamily(bbCell, comparable));
     assertEquals(0, PrivateCellUtil.compareFamily(kv, comparable));
+    // Qualifier starts with
+    kv = new KeyValue(r1, f, q1, v2);
+    assertTrue(PrivateCellUtil.qualifierStartsWith(kv, Bytes.toBytes("q")));
+    assertTrue(PrivateCellUtil.qualifierStartsWith(kv, q1));
+    assertFalse(PrivateCellUtil.qualifierStartsWith(kv, q2));
+    assertFalse(PrivateCellUtil.qualifierStartsWith(kv, Bytes.toBytes("longerthanthequalifier")));
   }
+
 }

hbase-common/src/main/java/org/apache/hadoop/hbase/PrivateCellUtil.java

@@ -767,6 +767,9 @@ public static boolean qualifierStartsWith(final Cell left, final byte[] startsWi
     if (startsWith == null || startsWith.length == 0) {
       throw new IllegalArgumentException("Cannot pass an empty startsWith");
     }
+    if (left.getQualifierLength() < startsWith.length) {
+      return false;
+    }
     if (left instanceof ByteBufferExtendedCell) {
       return ByteBufferUtils.equals(((ByteBufferExtendedCell) left).getQualifierByteBuffer(),
           ((ByteBufferExtendedCell) left).getQualifierPosition(), startsWith.length,