Merge remote-tracking branch 'origin/master' into doc-unified-tests

Author: MaxGekk

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/joinTypes.scala

@@ -102,7 +102,7 @@ case class NaturalJoin(tpe: JoinType) extends JoinType {
 }
 
 case class UsingJoin(tpe: JoinType, usingColumns: Seq[String]) extends JoinType {
-  require(Seq(Inner, LeftOuter, LeftSemi, RightOuter, FullOuter, LeftAnti).contains(tpe),
+  require(Seq(Inner, LeftOuter, LeftSemi, RightOuter, FullOuter, LeftAnti, Cross).contains(tpe),
     "Unsupported using join type " + tpe)
   override def sql: String = "USING " + tpe.sql
 }

sql/core/src/test/scala/org/apache/spark/sql/DataFrameJoinSuite.scala

@@ -122,6 +122,16 @@ class DataFrameJoinSuite extends QueryTest
       df2.crossJoin(df1),
       Row(2, "2", 1, "1") :: Row(2, "2", 3, "3") ::
         Row(4, "4", 1, "1") :: Row(4, "4", 3, "3") :: Nil)
+
+    checkAnswer(
+      df1.join(df2, Nil, "cross"),
+      Row(1, "1", 2, "2") :: Row(1, "1", 4, "4") ::
+        Row(3, "3", 2, "2") :: Row(3, "3", 4, "4") :: Nil)
+
+    checkAnswer(
+      df2.join(df1, Nil, "cross"),
+      Row(2, "2", 1, "1") :: Row(2, "2", 3, "3") ::
+        Row(4, "4", 1, "1") :: Row(4, "4", 3, "3") :: Nil)
   }
 
   test("broadcast join hint using broadcast function") {