remove support for arbitrary nested arrays

Author: cloud-fan

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/complexTypes.scala

@@ -71,74 +71,32 @@ case class GetItem(child: Expression, ordinal: Expression) extends Expression {
 }
 
 /**
- * Returns the value of fields in the `child`.
- * The type of `child` can be struct, or array of struct,
- * or array of array of struct, or array of array ... of struct.
+ * Returns the value of fields in the Struct `child`.
  */
 case class GetField(child: Expression, fieldName: String) extends UnaryExpression {
   type EvaluatedType = Any
 
-  lazy val dataType = {
-    structType
-    buildDataType(field.dataType)
-  }
-
+  def dataType = field.dataType
   override def nullable = child.nullable || field.nullable
   override def foldable = child.foldable
 
-  private var _buildDataType = identity[DataType] _
-  private lazy val buildDataType = {
-    structType
-    _buildDataType
-  }
-
-  private var _nestedArrayCount = 0
-  private lazy val nestedArrayCount = {
-    structType
-    _nestedArrayCount
-  }
-
-  private def getStructType(t: DataType): StructType = t match {
-    case ArrayType(elementType, containsNull) =>
-      _buildDataType = {(t: DataType) => ArrayType(t, containsNull)} andThen _buildDataType
-      _nestedArrayCount += 1
-      getStructType(elementType)
+  protected def structType = child.dataType match {
     case s: StructType => s
     case otherType => sys.error(s"GetField is not valid on fields of type $otherType")
   }
 
-  protected lazy val structType: StructType = {
-    child match {
-      case n: GetField =>
-        this._buildDataType = n._buildDataType
-        this._nestedArrayCount = n._nestedArrayCount
-        getStructType(n.field.dataType)
-      case _ => getStructType(child.dataType)
-    }
-  }
-
   lazy val field =
     structType.fields
         .find(_.name == fieldName)
         .getOrElse(sys.error(s"No such field $fieldName in ${child.dataType}"))
 
   lazy val ordinal = structType.fields.indexOf(field)
 
-  override lazy val resolved = childrenResolved
+  override lazy val resolved = childrenResolved && child.dataType.isInstanceOf[StructType]
 
   override def eval(input: Row): Any = {
-    val baseValue = child.eval(input)
-    evaluateValue(baseValue, nestedArrayCount)
-  }
-
-  private def evaluateValue(v: Any, count: Int): Any = {
-    if (v == null) {
-      null
-    } else if (count > 0) {
-      v.asInstanceOf[Seq[_]].map(r => evaluateValue(r, count - 1))
-    } else {
-      v.asInstanceOf[Row](ordinal)
-    }
+    val baseValue = child.eval(input).asInstanceOf[Row]
+    if (baseValue == null) null else baseValue(ordinal)
   }
 
   override def toString = s"$child.$fieldName"

sql/core/src/test/scala/org/apache/spark/sql/json/JsonSuite.scala

@@ -594,33 +594,5 @@ class JsonSuite extends QueryTest {
       sql("select complexArrayOfStruct[0].field1[1].inner2[0], complexArrayOfStruct[1].field2[0][1] from jsonTable"),
       ("str2", 6) :: Nil
     )
-
-    checkAnswer(
-      sql("select arrayOfStruct.field1, arrayOfStruct.field2 from jsonTable"),
-      (Seq(true, false, null), Seq("str1", null, null)) :: Nil
-    )
-
-    checkAnswer(
-      sql("select complexNestedArray.field, complexNestedArray.field.innerField from jsonTable"),
-      (
-        Seq(
-          Seq(
-            Seq("str1", null),
-            Seq("str2", null)
-          ),
-          Seq(
-            Seq("str3", null),
-            Seq(null, "str4")
-          ),
-          null
-        ),
-
-        Seq(
-          Seq("str1", "str2"),
-          Seq("str3", null),
-          null
-        )
-      ) :: Nil
-    )
   }
 }

sql/core/src/test/scala/org/apache/spark/sql/json/TestJsonData.scala

@@ -106,31 +106,6 @@ object TestJsonData {
               "inner1": "str4"
             }],
             "field2": [[5, 6], [7, 8]]
-          }],
-          "complexNestedArray": [
-          {
-            "field": [
-            {
-              "innerField": "str1"
-            },
-            {
-              "innerField": "str2"
-            }
-            ]
-          },
-          {
-            "field": [
-            {
-              "innerField": "str3"
-            },
-            {
-              "otherInner": "str4"
-            }
-            ]
-          },
-          {
-            "otherField": "str5"
-          }
-          ]
+          }]
       }""" :: Nil)
 }