[SPARK-23586][SQL] Add interpreted execution to WrapOption

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

@@ -422,8 +422,7 @@ case class WrapOption(child: Expression, optType: DataType)
 
   override def inputTypes: Seq[AbstractDataType] = optType :: Nil
 
-  override def eval(input: InternalRow): Any =
-    throw new UnsupportedOperationException("Only code-generated evaluation is supported")
+  override def eval(input: InternalRow): Any = Option(child.eval(input))
 
   override def doGenCode(ctx: CodegenContext, ev: ExprCode): ExprCode = {
     val inputObject = child.genCode(ctx)

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/ObjectExpressionsSuite.scala

@@ -20,7 +20,7 @@ package org.apache.spark.sql.catalyst.expressions
 import org.apache.spark.SparkFunSuite
 import org.apache.spark.sql.catalyst.InternalRow
 import org.apache.spark.sql.catalyst.encoders.ExpressionEncoder
-import org.apache.spark.sql.catalyst.expressions.objects.{Invoke, UnwrapOption}
+import org.apache.spark.sql.catalyst.expressions.objects._
 import org.apache.spark.sql.catalyst.util.{ArrayBasedMapData, GenericArrayData}
 import org.apache.spark.sql.types.{IntegerType, ObjectType}
 
@@ -75,4 +75,14 @@ class ObjectExpressionsSuite extends SparkFunSuite with ExpressionEvalHelper {
       checkEvaluation(unwrapObject, expected, InternalRow.fromSeq(Seq(input)))
     }
   }
+
+  test("SPARK-23586: WrapOption should support interpreted execution") {
+    val cls = ObjectType(classOf[java.lang.Integer])
+    val inputObject = BoundReference(0, cls, nullable = true)
+    val unwrapObject = WrapOption(inputObject, cls)
+    unwrapObject.resolved
+    Seq((1, Some(1)), (null, None)).foreach { case (input, expected) =>
+      checkEvaluation(unwrapObject, expected, InternalRow.fromSeq(Seq(input)))
+    }
+  }
 }