From 5585f1aee6c2631325975ff005f675cdb00a03eb Mon Sep 17 00:00:00 2001
From: "opensearch-trigger-bot[bot]"
 <98922864+opensearch-trigger-bot[bot]@users.noreply.github.com>
Date: Wed, 20 Nov 2024 16:06:53 -0800
Subject: [PATCH] Add support for serializing MapType (#929) (#939)

(cherry picked from commit 8efe1ec41b19939c72b4f8ef315ea22903778d50)

Signed-off-by: Chase Engelbrecht <engechas@amazon.com>
Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
---
 .../spark/sql/flint/datatype/FlintDataType.scala  |  3 +++
 .../sql/flint/datatype/FlintDataTypeSuite.scala   | 15 +++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/flint-spark-integration/src/main/scala/org/apache/spark/sql/flint/datatype/FlintDataType.scala b/flint-spark-integration/src/main/scala/org/apache/spark/sql/flint/datatype/FlintDataType.scala
index a4b23bd46..5d920a07e 100644
--- a/flint-spark-integration/src/main/scala/org/apache/spark/sql/flint/datatype/FlintDataType.scala
+++ b/flint-spark-integration/src/main/scala/org/apache/spark/sql/flint/datatype/FlintDataType.scala
@@ -153,6 +153,9 @@ object FlintDataType {
       // objects
       case st: StructType => serializeJValue(st)
 
+      // Serialize maps as empty objects and let the map entries automap
+      case mt: MapType => serializeJValue(new StructType())
+
       // array
       case ArrayType(elementType, _) => serializeField(elementType, Metadata.empty)
 
diff --git a/flint-spark-integration/src/test/scala/org/apache/spark/sql/flint/datatype/FlintDataTypeSuite.scala b/flint-spark-integration/src/test/scala/org/apache/spark/sql/flint/datatype/FlintDataTypeSuite.scala
index 94f4839d6..44e8158d8 100644
--- a/flint-spark-integration/src/test/scala/org/apache/spark/sql/flint/datatype/FlintDataTypeSuite.scala
+++ b/flint-spark-integration/src/test/scala/org/apache/spark/sql/flint/datatype/FlintDataTypeSuite.scala
@@ -128,6 +128,21 @@ class FlintDataTypeSuite extends FlintSuite with Matchers {
                                                                     |}""".stripMargin)
   }
 
+  test("spark map type serialize") {
+    val sparkStructType = StructType(
+      StructField("mapField", MapType(StringType, StringType), true) ::
+        Nil)
+
+    FlintDataType.serialize(sparkStructType) shouldBe compactJson("""{
+                                                                    |  "properties": {
+                                                                    |    "mapField": {
+                                                                    |      "properties": {
+                                                                    |      }
+                                                                    |    }
+                                                                    |  }
+                                                                    |}""".stripMargin)
+  }
+
   test("spark varchar and char type serialize") {
     val flintDataType = """{
                           |  "properties": {