[SPARK-11894][SQL] fix isNull for GetInternalRowField

We should use `InternalRow.isNullAt` to check if the field is null before calling `InternalRow.getXXX`

Thanks gatorsmile who discovered this bug.

Author: Wenchen Fan <wenchen@databricks.com>

Closes #9904 from cloud-fan/null.

1 files changed, 9 insertions, 14 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 82317d3385..4a1f419f0a 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
@@ -236,11 +236,6 @@ case class NewInstance(
     }
 
     if (propagateNull) {
-      val objNullCheck = if (ctx.defaultValue(dataType) == "null") {
-        s"${ev.isNull} = ${ev.value} == null;"
-      } else {
-        ""
-      }
       val argsNonNull = s"!(${argGen.map(_.isNull).mkString(" || ")})"
 
       s"""
@@ -531,15 +526,15 @@ case class GetInternalRowField(child: Expression, ordinal: Int, dataType: DataTy
     throw new UnsupportedOperationException("Only code-generated evaluation is supported")
 
   override def genCode(ctx: CodeGenContext, ev: GeneratedExpressionCode): String = {
-    val row = child.gen(ctx)
-    s"""
-      ${row.code}
-      final boolean ${ev.isNull} = ${row.isNull};
-      ${ctx.javaType(dataType)} ${ev.value} = ${ctx.defaultValue(dataType)};
-      if (!${ev.isNull}) {
-        ${ev.value} = ${ctx.getValue(row.value, dataType, ordinal.toString)};
-      }
-    """
+    nullSafeCodeGen(ctx, ev, eval => {
+      s"""
+        if ($eval.isNullAt($ordinal)) {
+          ${ev.isNull} = true;
+        } else {
+          ${ev.value} = ${ctx.getValue(eval, dataType, ordinal.toString)};
+        }
+      """
+    })
   }
 }