From fa7e1b1dccb007840cbd536707d6d7ea098ffb9a Mon Sep 17 00:00:00 2001
From: Takuya UESHIN <ueshin@databricks.com>
Date: Thu, 9 Aug 2018 01:12:42 +0900
Subject: [PATCH] Fix comparison of `ev.code`.

---
 .../spark/sql/catalyst/expressions/codegen/javaCode.scala     | 4 +++-
 .../apache/spark/sql/execution/WholeStageCodegenExec.scala    | 2 +-
 .../spark/sql/execution/joins/BroadcastHashJoinExec.scala     | 2 +-
 3 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/codegen/javaCode.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/codegen/javaCode.scala
index 2f8c853e836ba..558cbfa560053 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/codegen/javaCode.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/codegen/javaCode.scala
@@ -130,7 +130,9 @@ trait Block extends TreeNode[Block] with JavaCode {
 
   def length: Int = toString.length
 
-  def nonEmpty: Boolean = toString.nonEmpty
+  def isEmpty: Boolean = toString.isEmpty
+
+  def nonEmpty: Boolean = !isEmpty
 
   // The leading prefix that should be stripped from each line.
   // By default we strip blanks or control characters followed by '|' from the line.
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/WholeStageCodegenExec.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/WholeStageCodegenExec.scala
index 372dc3db36ce6..80f886ea1adc8 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/WholeStageCodegenExec.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/WholeStageCodegenExec.scala
@@ -275,7 +275,7 @@ trait CodegenSupport extends SparkPlan {
       required: AttributeSet): String = {
     val evaluateVars = new StringBuilder
     variables.zipWithIndex.foreach { case (ev, i) =>
-      if (ev.code != "" && required.contains(attributes(i))) {
+      if (ev.code.nonEmpty && required.contains(attributes(i))) {
         evaluateVars.append(ev.code.toString + "\n")
         ev.code = EmptyBlock
       }
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/joins/BroadcastHashJoinExec.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/joins/BroadcastHashJoinExec.scala
index 0da0e8610c392..a6f3ea47c8492 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/joins/BroadcastHashJoinExec.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/joins/BroadcastHashJoinExec.scala
@@ -320,7 +320,7 @@ case class BroadcastHashJoinExec(
          |if (!$conditionPassed) {
          |  $matched = null;
          |  // reset the variables those are already evaluated.
-         |  ${buildVars.filter(_.code == "").map(v => s"${v.isNull} = true;").mkString("\n")}
+         |  ${buildVars.filter(_.code.isEmpty).map(v => s"${v.isNull} = true;").mkString("\n")}
          |}
          |$numOutput.add(1);
          |${consume(ctx, resultVars)}