2 files changed, 20 insertions, 3 deletions
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/objects.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/objects.scala
index 28b6b2adf8..26b1ff39b3 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/objects.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/objects.scala
@@ -446,6 +446,8 @@ case class MapObjects private(
   override def genCode(ctx: CodegenContext, ev: ExprCode): String = {
     val javaType = ctx.javaType(dataType)
     val elementJavaType = ctx.javaType(loopVar.dataType)
+    ctx.addMutableState("boolean", loopVar.isNull, "")
+    ctx.addMutableState(elementJavaType, loopVar.value, "")
     val genInputData = inputData.gen(ctx)
     val genFunction = lambdaFunction.gen(ctx)
     val dataLength = ctx.freshName("dataLength")
@@ -466,9 +468,9 @@ case class MapObjects private(
     }
 
     val loopNullCheck = if (primitiveElement) {
-      s"boolean ${loopVar.isNull} = ${genInputData.value}.isNullAt($loopIndex);"
+      s"${loopVar.isNull} = ${genInputData.value}.isNullAt($loopIndex);"
     } else {
-      s"boolean ${loopVar.isNull} = ${genInputData.isNull} || ${loopVar.value} == null;"
+      s"${loopVar.isNull} = ${genInputData.isNull} || ${loopVar.value} == null;"
     }
 
     s"""
@@ -484,7 +486,7 @@ case class MapObjects private(
 
         int $loopIndex = 0;
         while ($loopIndex < $dataLength) {
-          $elementJavaType ${loopVar.value} =
+          ${loopVar.value} =
             ($elementJavaType)${genInputData.value}${itemAccessor(loopIndex)};
           $loopNullCheck
 
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/execution/datasources/json/JsonSuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/execution/datasources/json/JsonSuite.scala
index 2a18acb95b..e17340c70b 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/execution/datasources/json/JsonSuite.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/execution/datasources/json/JsonSuite.scala
@@ -1664,4 +1664,19 @@ class JsonSuite extends QueryTest with SharedSQLContext with TestJsonData {
       )
     }
   }
+
+  test("wide nested json table") {
+    val nested = (1 to 100).map { i =>
+      s"""
+         |"c$i": $i
+       """.stripMargin
+    }.mkString(", ")
+    val json = s"""
+       |{"a": [{$nested}], "b": [{$nested}]}
+     """.stripMargin
+    val rdd = sqlContext.sparkContext.makeRDD(Seq(json))
+    val df = sqlContext.read.json(rdd)
+    assert(df.schema.size === 2)
+    df.collect()
+  }
 }