[SPARK-4052][SQL] Use scala.collection.Map for pattern matching instead of using Predef.Map (it is scala.collection.immutable.Map)

Please check https://issues.apache.org/jira/browse/SPARK-4052 for cases triggering this bug.

Author: Yin Huai <huai@cse.ohio-state.edu>

Closes #2899 from yhuai/SPARK-4052 and squashes the following commits:

1188f70 [Yin Huai] Address liancheng's comments.
b6712be [Yin Huai] Use scala.collection.Map instead of Predef.Map (scala.collection.immutable.Map).

2 files changed, 22 insertions, 0 deletions

diff --git a/sql/hive/src/main/scala/org/apache/spark/sql/hive/execution/InsertIntoHiveTable.scala b/sql/hive/src/main/scala/org/apache/spark/sql/hive/execution/InsertIntoHiveTable.scala
index 7db5fd804d..79234f8a66 100644
--- a/sql/hive/src/main/scala/org/apache/spark/sql/hive/execution/InsertIntoHiveTable.scala
+++ b/sql/hive/src/main/scala/org/apache/spark/sql/hive/execution/InsertIntoHiveTable.scala
@@ -93,6 +93,10 @@ case class InsertIntoHiveTable(
       (o: Any) => seqAsJavaList(o.asInstanceOf[Seq[_]].map(wrapper))
 
     case moi: MapObjectInspector =>
+      // The Predef.Map is scala.collection.immutable.Map.
+      // Since the map values can be mutable, we explicitly import scala.collection.Map at here.
+      import scala.collection.Map
+
       val keyWrapper = wrapperFor(moi.getMapKeyObjectInspector)
       val valueWrapper = wrapperFor(moi.getMapValueObjectInspector)
       (o: Any) => mapAsJavaMap(o.asInstanceOf[Map[_, _]].map { case (key, value) =>
diff --git a/sql/hive/src/test/scala/org/apache/spark/sql/hive/InsertIntoHiveTableSuite.scala b/sql/hive/src/test/scala/org/apache/spark/sql/hive/InsertIntoHiveTableSuite.scala
index 7e323146f9..18dc937dd2 100644
--- a/sql/hive/src/test/scala/org/apache/spark/sql/hive/InsertIntoHiveTableSuite.scala
+++ b/sql/hive/src/test/scala/org/apache/spark/sql/hive/InsertIntoHiveTableSuite.scala
@@ -18,6 +18,7 @@
 package org.apache.spark.sql.hive
 
 import org.apache.spark.sql.QueryTest
+import org.apache.spark.sql._
 import org.apache.spark.sql.hive.test.TestHive
 
 /* Implicits */
@@ -73,4 +74,21 @@ class InsertIntoHiveTableSuite extends QueryTest {
     createTable[TestData]("createAndInsertTest")
     createTable[TestData]("createAndInsertTest")
   }
+
+  test("SPARK-4052: scala.collection.Map as value type of MapType") {
+    val schema = StructType(StructField("m", MapType(StringType, StringType), true) :: Nil)
+    val rowRDD = TestHive.sparkContext.parallelize(
+      (1 to 100).map(i => Row(scala.collection.mutable.HashMap(s"key$i" -> s"value$i"))))
+    val schemaRDD = applySchema(rowRDD, schema)
+    schemaRDD.registerTempTable("tableWithMapValue")
+    sql("CREATE TABLE hiveTableWithMapValue(m MAP <STRING, STRING>)")
+    sql("INSERT OVERWRITE TABLE hiveTableWithMapValue SELECT m FROM tableWithMapValue")
+
+    checkAnswer(
+      sql("SELECT * FROM hiveTableWithMapValue"),
+      rowRDD.collect().toSeq
+    )
+
+    sql("DROP TABLE hiveTableWithMapValue")
+  }
 }