[SPARK-10130] [SQL] type coercion for IF should have children resolved first

Type coercion for IF should have children resolved first, or we could meet unresolved exception.

Author: Daoyuan Wang <daoyuan.wang@intel.com>

Closes #8331 from adrian-wang/spark10130.

2 files changed, 8 insertions, 0 deletions

diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/HiveTypeCoercion.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/HiveTypeCoercion.scala
index f2f2ba2f96..2cb067f4aa 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/HiveTypeCoercion.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/HiveTypeCoercion.scala
@@ -639,6 +639,7 @@ object HiveTypeCoercion {
    */
   object IfCoercion extends Rule[LogicalPlan] {
     def apply(plan: LogicalPlan): LogicalPlan = plan resolveExpressions {
+      case e if !e.childrenResolved => e
       // Find tightest common type for If, if the true value and false value have different types.
       case i @ If(pred, left, right) if left.dataType != right.dataType =>
         findTightestCommonTypeToString(left.dataType, right.dataType).map { widestType =>
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala
index da50aec17c..dcb4e83710 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala
@@ -1679,4 +1679,11 @@ class SQLQuerySuite extends QueryTest with SharedSQLContext {
       checkAnswer(sqlContext.table("`db.t`"), df)
     }
   }
+
+  test("SPARK-10130 type coercion for IF should have children resolved first") {
+    val df = Seq((1, 1), (-1, 1)).toDF("key", "value")
+    df.registerTempTable("src")
+    checkAnswer(
+      sql("SELECT IF(a > 0, a, 0) FROM (SELECT key a FROM src) temp"), Seq(Row(1), Row(0)))
+  }
 }