From 86106fadcaed6c1a4768138b3d72e8c892b7cd7f Mon Sep 17 00:00:00 2001
From: Marco Gaido <marcogaido91@gmail.com>
Date: Sat, 17 Nov 2018 15:36:45 +0100
Subject: [PATCH] address comments

---
 .../spark/sql/catalyst/optimizer/subquery.scala    |  3 +--
 .../scala/org/apache/spark/sql/SubquerySuite.scala | 14 ++++++++------
 2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/subquery.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/subquery.scala
index c11470a22908e..ea658ad461f7e 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/subquery.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/subquery.scala
@@ -76,8 +76,7 @@ object RewritePredicateSubquery extends Rule[LogicalPlan] with PredicateHelper {
 
   private def dedupSubqueryOnSelfJoin(values: Seq[Expression], sub: LogicalPlan): LogicalPlan = {
     val leftRefs = AttributeSet.fromAttributeSets(values.map(_.references))
-    val rightRefs = AttributeSet(sub.output)
-    val duplicates = leftRefs.intersect(rightRefs)
+    val duplicates = leftRefs.intersect(sub.outputSet)
     if (duplicates.isEmpty) {
       sub
     } else {
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/SubquerySuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/SubquerySuite.scala
index 5a525a6d4ab28..007a063d071cf 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/SubquerySuite.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/SubquerySuite.scala
@@ -1284,12 +1284,14 @@ class SubquerySuite extends QueryTest with SharedSQLContext {
 
   test("SPARK-26078: deduplicate fake self joins for IN subqueries") {
     withTempView("a", "b") {
-      val a = spark.createDataFrame(spark.sparkContext.parallelize(Seq(Row("a", 2), Row("b", 1))),
-        StructType(Seq(StructField("id", StringType), StructField("num", IntegerType))))
-      val b = spark.createDataFrame(spark.sparkContext.parallelize(Seq(Row("a", 2), Row("b", 1))),
-        StructType(Seq(StructField("id", StringType), StructField("num", IntegerType))))
-      a.createOrReplaceTempView("a")
-      b.createOrReplaceTempView("b")
+      def genTestViewWithName(name: String): Unit = {
+        val df = spark.createDataFrame(
+          spark.sparkContext.parallelize(Seq(Row("a", 2), Row("b", 1))),
+          StructType(Seq(StructField("id", StringType), StructField("num", IntegerType))))
+        df.createOrReplaceTempView(name)
+      }
+      genTestViewWithName("a")
+      genTestViewWithName("b")
 
       val df1 = spark.sql(
         """