SPARK-5984: Fix TimSort bug causes ArrayOutOfBoundsException

Author: hotou

core/src/test/java/org/apache/spark/util/collection/TestTimSort.java

@@ -3,10 +3,16 @@
 import java.util.*;
 
 /**
- * This codes generates a int array which fails the standard TimSort, Borrowed from
- * the reporter of this bug.
+ * This codes generates a int array which fails the standard TimSort.
  *
+ * The blog that reported the bug
  * http://www.envisage-project.eu/timsort-specification-and-verification/
+ *
+ * The algorithms to reproduce the bug is obtained from the reporter of the bug
+ * https://github.com/abstools/java-timsort-bug
+ *
+ * Licensed under Apache License 2.0
+ * https://github.com/abstools/java-timsort-bug/blob/master/LICENSE
  */
 public class TestTimSort {
 

core/src/test/scala/org/apache/spark/util/collection/SorterSuite.scala

@@ -65,10 +65,11 @@ class SorterSuite extends FunSuite {
     }
   }
 
-  test("bug of TimSort") {
+  // http://www.envisage-project.eu/timsort-specification-and-verification/
+  test("SPARK-5984 TimSort bug") {
     val data = TestTimSort.getTimSortBugTestSet(67108864)
     new Sorter(new IntArraySortDataFormat).sort(data, 0, data.length, Ordering.Int)
-    (0 to data.length - 2).foreach(i => assert(data(i) <= data(i+1)))
+    (0 to data.length - 2).foreach(i => assert(data(i) <= data(i + 1)))
   }
 
   /** Runs an experiment several times. */