File _service:obs_scm:0017-fix-log-clean.patch of Package kafka

diff --git a/core/src/main/scala/kafka/log/LogCleaner.scala b/core/src/main/scala/kafka/log/LogCleaner.scala
index 7a8a13c6e7..177b460d38 100644
--- a/core/src/main/scala/kafka/log/LogCleaner.scala
+++ b/core/src/main/scala/kafka/log/LogCleaner.scala
@@ -840,7 +840,10 @@ private[log] class Cleaner(val id: Int,
             logSize + segs.head.size <= maxSize &&
             indexSize + segs.head.offsetIndex.sizeInBytes <= maxIndexSize &&
             timeIndexSize + segs.head.timeIndex.sizeInBytes <= maxIndexSize &&
-            lastOffsetForFirstSegment(segs, firstUncleanableOffset) - group.last.baseOffset <= Int.MaxValue) {
+            //if first segment size is 0, we don't need to do the index offset range check.
+            //this will avoid empty log left every 2^31 message.
+            (segs.head.size == 0 ||
+              lastOffsetForFirstSegment(segs, firstUncleanableOffset) - group.last.baseOffset <= Int.MaxValue)) {
         group = segs.head :: group
         logSize += segs.head.size
         indexSize += segs.head.offsetIndex.sizeInBytes
diff --git a/core/src/test/scala/unit/kafka/log/LogCleanerTest.scala b/core/src/test/scala/unit/kafka/log/LogCleanerTest.scala
index 43bc3b9f28..e5984c4f31 100755
--- a/core/src/test/scala/unit/kafka/log/LogCleanerTest.scala
+++ b/core/src/test/scala/unit/kafka/log/LogCleanerTest.scala
@@ -1258,6 +1258,53 @@ class LogCleanerTest {
       "All but the last group should be the target size.")
   }
 
+  @Test
+  def testSegmentGroupingWithSparseOffsetsAndEmptySegments(): Unit ={
+    val cleaner = makeCleaner(Int.MaxValue)
+    val logProps = new Properties()
+    val log = makeLog(config = LogConfig.fromProps(logConfig.originals, logProps))
+
+    val k="key".getBytes()
+    val v="val".getBytes()
+
+    //create 3 segments
+    for(i <- 0 until 3){
+      log.appendAsLeader(TestUtils.singletonRecords(value = v, key = k), leaderEpoch = 0)
+      //0 to Int.MaxValue is Int.MaxValue+1 message, -1 will be the last message of i-th segment
+      val records = messageWithOffset(k, v, (i + 1L) * (Int.MaxValue + 1L) -1 )
+      log.appendAsFollower(records)
+      assertEquals(i + 1, log.numberOfSegments)
+    }
+
+    //4th active segment, not clean
+    log.appendAsLeader(TestUtils.singletonRecords(value = v, key = k), leaderEpoch = 0)
+
+    val totalSegments = 4
+    //last segment not cleanable
+    val firstUncleanableOffset = log.logEndOffset - 1
+    val notCleanableSegments = 1
+
+    assertEquals(totalSegments, log.numberOfSegments)
+    var groups = cleaner.groupSegmentsBySize(log.logSegments, maxSize = Int.MaxValue, maxIndexSize = Int.MaxValue, firstUncleanableOffset)
+    //because index file uses 4 byte relative index offset and current segments all none empty,
+    //segments will not group even their size is very small.
+    assertEquals(totalSegments - notCleanableSegments, groups.size)
+    //do clean to clean first 2 segments to empty
+    cleaner.clean(LogToClean(log.topicPartition, log, 0, firstUncleanableOffset))
+    assertEquals(totalSegments, log.numberOfSegments)
+    assertEquals(0, log.logSegments.head.size)
+
+    //after clean we got 2 empty segment, they will group together this time
+    groups = cleaner.groupSegmentsBySize(log.logSegments, maxSize = Int.MaxValue, maxIndexSize = Int.MaxValue, firstUncleanableOffset)
+    val noneEmptySegment = 1
+    assertEquals(noneEmptySegment + 1, groups.size)
+
+    //trigger a clean and 2 empty segments should cleaned to 1
+    cleaner.clean(LogToClean(log.topicPartition, log, 0, firstUncleanableOffset))
+    assertEquals(totalSegments - 1, log.numberOfSegments)
+  }
+
+
   /**
    * Validate the logic for grouping log segments together for cleaning when only a small number of
    * messages are retained, but the range of offsets is greater than Int.MaxValue. A group should not