[QUICKFIX] [SQL] fix copy of generated row

copy() of generated Row doesn't check nullability of columns

Author: Davies Liu <davies@databricks.com>

Closes #7163 from davies/fix_copy and squashes the following commits:

661a206 [Davies Liu] fix copy of generated row

2 files changed, 4 insertions, 1 deletions

diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/codegen/GenerateProjection.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/codegen/GenerateProjection.scala
index 5be47175fa..3c7ee9cc16 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/codegen/GenerateProjection.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/codegen/GenerateProjection.scala
@@ -148,7 +148,7 @@ object GenerateProjection extends CodeGenerator[Seq[Expression], Projection] {
     }.mkString("\n")
 
     val copyColumns = expressions.zipWithIndex.map { case (e, i) =>
-        s"""arr[$i] = c$i;"""
+        s"""if (!nullBits[$i]) arr[$i] = c$i;"""
     }.mkString("\n      ")
 
     val code = s"""
diff --git a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/ExpressionEvalHelper.scala b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/ExpressionEvalHelper.scala
index 7d95ef7f71..3171caf6ad 100644
--- a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/ExpressionEvalHelper.scala
+++ b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/ExpressionEvalHelper.scala
@@ -136,6 +136,9 @@ trait ExpressionEvalHelper {
       val input = if (inputRow == EmptyRow) "" else s", input: $inputRow"
       fail(s"Incorrect Evaluation: $expression, actual: $actual, expected: $expected$input")
     }
+    if (actual.copy() != expectedRow) {
+      fail(s"Copy of generated Row is wrong: actual: ${actual.copy()}, expected: $expectedRow")
+    }
   }
 
   protected def checkEvaluationWithOptimization(