HBASE-18030 Per Cell TTL tags may get duplicated with increments/Append causing tags length overflow.

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

@@ -277,6 +277,16 @@ public final class TagUtil {
     // tag-handling).
     if (tags == null) {
       tags = new ArrayList<>(1);
+    } else {
+      // Remove existing TTL tags if any
+      Iterator<Tag> tagsItr = tags.iterator();
+      while (tagsItr.hasNext()) {
+        Tag tag = tagsItr.next();
+        if (tag.getType() == TagType.TTL_TAG_TYPE) {
+          tagsItr.remove();
+          break;
+        }
+      }
     }
     tags.add(new ArrayBackedTag(TagType.TTL_TAG_TYPE, Bytes.toBytes(ttl)));
     return tags;

hbase-common/src/test/java/org/apache/hadoop/hbase/TestTagUtil.java

@@ -0,0 +1,49 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hbase;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.List;
+
+import org.apache.hadoop.hbase.testclassification.MiscTests;
+import org.apache.hadoop.hbase.testclassification.SmallTests;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+
+@Category({ MiscTests.class, SmallTests.class })
+public class TestTagUtil {
+
+  @Test
+  public void testCarryForwardTTLTag() throws Exception {
+    // No tags so far and the TTL tag must get added to the Tags list
+    long ttl = 10 * 1000;
+    List<Tag> tags = TagUtil.carryForwardTTLTag(null, ttl);
+    assertEquals(1, tags.size());
+    Tag ttlTag = tags.get(0);
+    assertEquals(TagType.TTL_TAG_TYPE, ttlTag.getType());
+    assertEquals(ttl, TagUtil.getValueAsLong(ttlTag));
+    // Already having a TTL tag in the list. So the call must remove the old tag
+    long ttl2 = 30 * 1000;
+    tags = TagUtil.carryForwardTTLTag(tags, ttl2);
+    assertEquals(1, tags.size());
+    ttlTag = tags.get(0);
+    assertEquals(TagType.TTL_TAG_TYPE, ttlTag.getType());
+    assertEquals(ttl2, TagUtil.getValueAsLong(ttlTag));
+  }
+}