[SPARK-2779] [SQL] asInstanceOf[Map[...]] should use scala.collection.Map instead of scala.collection.immutable.Map

Since we let users create Rows. It makes sense to accept mutable Maps as values of MapType columns.

JIRA: https://issues.apache.org/jira/browse/SPARK-2779

Author: Yin Huai <[email protected]>

Closes apache#1705 from yhuai/SPARK-2779 and squashes the following commits:

00d72fd [Yin Huai] Use scala.collection.Map.

Author: yhuai

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/complexTypes.scala

@@ -17,6 +17,8 @@
 
 package org.apache.spark.sql.catalyst.expressions
 
+import scala.collection.Map
+
 import org.apache.spark.sql.catalyst.types._
 
 /**

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/generators.scala

@@ -17,6 +17,8 @@
 
 package org.apache.spark.sql.catalyst.expressions
 
+import scala.collection.Map
+
 import org.apache.spark.sql.catalyst.trees
 import org.apache.spark.sql.catalyst.types._
 

sql/core/src/main/scala/org/apache/spark/sql/json/JsonRDD.scala

@@ -17,6 +17,7 @@
 
 package org.apache.spark.sql.json
 
+import scala.collection.Map
 import scala.collection.convert.Wrappers.{JMapWrapper, JListWrapper}
 import scala.math.BigDecimal
 

sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala

@@ -505,5 +505,24 @@ class SQLQuerySuite extends QueryTest {
       (2, null) ::
       (3, null) ::
       (4, 2147483644) :: Nil)
+
+    // The value of a MapType column can be a mutable map.
+    val rowRDD3 = unparsedStrings.map { r =>
+      val values = r.split(",").map(_.trim)
+      val v4 = try values(3).toInt catch {
+        case _: NumberFormatException => null
+      }
+      Row(Row(values(0).toInt, values(2).toBoolean), scala.collection.mutable.Map(values(1) -> v4))
+    }
+
+    val schemaRDD3 = applySchema(rowRDD3, schema2)
+    schemaRDD3.registerAsTable("applySchema3")
+
+    checkAnswer(
+      sql("SELECT f1.f11, f2['D4'] FROM applySchema3"),
+      (1, null) ::
+      (2, null) ::
+      (3, null) ::
+      (4, 2147483644) :: Nil)
   }
 }