2 files changed, 17 insertions, 0 deletions
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
index 2bca31d5f1..9bc8cea377 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
@@ -688,6 +688,14 @@ object FoldablePropagation extends Rule[LogicalPlan] {
         case c: Command =>
           stop = true
           c
+        // For outer join, although its output attributes are derived from its children, they are
+        // actually different attributes: the output of outer join is not always picked from its
+        // children, but can also be null.
+        // TODO(cloud-fan): It seems more reasonable to use new attributes as the output attributes
+        // of outer join.
+        case j @ Join(_, _, LeftOuter | RightOuter | FullOuter, _) =>
+          stop = true
+          j
         case p: LogicalPlan if !stop => p.transformExpressions {
           case a: AttributeReference if foldableMap.contains(a) =>
             foldableMap(a)
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/DataFrameSuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/DataFrameSuite.scala
index 6a0a7df3f4..9d53be8e2b 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/DataFrameSuite.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/DataFrameSuite.scala
@@ -1562,4 +1562,13 @@ class DataFrameSuite extends QueryTest with SharedSQLContext {
     val df = Seq(1, 1, 2).toDF("column.with.dot")
     checkAnswer(df.distinct(), Row(1) :: Row(2) :: Nil)
   }
+
+  test("SPARK-16181: outer join with isNull filter") {
+    val left = Seq("x").toDF("col")
+    val right = Seq("y").toDF("col").withColumn("new", lit(true))
+    val joined = left.join(right, left("col") === right("col"), "left_outer")
+
+    checkAnswer(joined, Row("x", null, null))
+    checkAnswer(joined.filter($"new".isNull), Row("x", null, null))
+  }
 }