UniqueKeyHashedRelation.get should return null if the value is null.

Author: rxin

sql/core/src/main/scala/org/apache/spark/sql/execution/joins/HashedRelation.scala

@@ -49,7 +49,10 @@ private[joins] final class GeneralHashedRelation(hashTable: JavaHashMap[Row, Com
 final class UniqueKeyHashedRelation(hashTable: JavaHashMap[Row, Row])
   extends HashedRelation with Serializable {
 
-  override def get(key: Row) = CompactBuffer(hashTable.get(key))
+  override def get(key: Row) = {
+    val v = hashTable.get(key)
+    if (v eq null) null else CompactBuffer(v)
+  }
 
   def getValue(key: Row): Row = hashTable.get(key)
 }

sql/core/src/test/scala/org/apache/spark/sql/execution/joins/HashedRelationSuite.scala

@@ -37,6 +37,7 @@ class HashedRelationSuite extends FunSuite {
 
     assert(hashed.get(data(0)) == CompactBuffer[Row](data(0)))
     assert(hashed.get(data(1)) == CompactBuffer[Row](data(1)))
+    assert(hashed.get(Row(10)) === null)
 
     val data2 = CompactBuffer[Row](data(2))
     data2 += data(2)
@@ -51,10 +52,12 @@ class HashedRelationSuite extends FunSuite {
     assert(hashed.get(data(0)) == CompactBuffer[Row](data(0)))
     assert(hashed.get(data(1)) == CompactBuffer[Row](data(1)))
     assert(hashed.get(data(2)) == CompactBuffer[Row](data(2)))
+    assert(hashed.get(Row(10)) === null)
 
     val uniqHashed = hashed.asInstanceOf[UniqueKeyHashedRelation]
     assert(uniqHashed.getValue(data(0)) == data(0))
     assert(uniqHashed.getValue(data(1)) == data(1))
     assert(uniqHashed.getValue(data(2)) == data(2))
+    assert(uniqHashed.getValue(Row(10)) == null)
   }
 }