From 742213d7105dddf91d4bc414e1ef72b198109541 Mon Sep 17 00:00:00 2001
From: Ryan Ernst <ryan@elastic.co>
Date: Fri, 16 Aug 2019 11:39:03 -0700
Subject: [PATCH] Improve error message when index settings are not a map
 (#45588)

This commit adds an explicit error message when a create index request
contains a settings key that is not a json object. Prior to this change
the user would be given a ClassCastException with no explanation of what
went wrong.

closes #45126
---
 .../admin/indices/create/CreateIndexRequest.java       |  3 +++
 .../admin/indices/create/CreateIndexRequestTests.java  | 10 ++++++++++
 2 files changed, 13 insertions(+)

diff --git a/server/src/main/java/org/elasticsearch/action/admin/indices/create/CreateIndexRequest.java b/server/src/main/java/org/elasticsearch/action/admin/indices/create/CreateIndexRequest.java
index 11f09f3c7bb..202ce364ebf 100644
--- a/server/src/main/java/org/elasticsearch/action/admin/indices/create/CreateIndexRequest.java
+++ b/server/src/main/java/org/elasticsearch/action/admin/indices/create/CreateIndexRequest.java
@@ -402,6 +402,9 @@ public class CreateIndexRequest extends AcknowledgedRequest<CreateIndexRequest>
         for (Map.Entry<String, ?> entry : source.entrySet()) {
             String name = entry.getKey();
             if (SETTINGS.match(name, deprecationHandler)) {
+                if (entry.getValue() instanceof Map == false) {
+                    throw new ElasticsearchParseException("key [settings] must be an object");
+                }
                 settings((Map<String, Object>) entry.getValue());
             } else if (MAPPINGS.match(name, deprecationHandler)) {
                 Map<String, Object> mappings = (Map<String, Object>) entry.getValue();
diff --git a/server/src/test/java/org/elasticsearch/action/admin/indices/create/CreateIndexRequestTests.java b/server/src/test/java/org/elasticsearch/action/admin/indices/create/CreateIndexRequestTests.java
index 419d669d066..e95c4e43774 100644
--- a/server/src/test/java/org/elasticsearch/action/admin/indices/create/CreateIndexRequestTests.java
+++ b/server/src/test/java/org/elasticsearch/action/admin/indices/create/CreateIndexRequestTests.java
@@ -44,6 +44,7 @@ import java.util.Set;
 
 import static org.elasticsearch.cluster.metadata.IndexMetaData.SETTING_NUMBER_OF_SHARDS;
 import static org.elasticsearch.common.xcontent.ToXContent.EMPTY_PARAMS;
+import static org.hamcrest.CoreMatchers.equalTo;
 
 public class CreateIndexRequestTests extends ESTestCase {
 
@@ -196,6 +197,15 @@ public class CreateIndexRequestTests extends ESTestCase {
         ElasticsearchAssertions.assertToXContentEquivalent(originalBytes, finalBytes, xContentType);
     }
 
+    public void testSettingsType() throws IOException {
+        XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        builder.startObject().startArray("settings").endArray().endObject();
+
+        CreateIndexRequest parsedCreateIndexRequest = new CreateIndexRequest();
+        ElasticsearchParseException e = expectThrows(ElasticsearchParseException.class, () -> parsedCreateIndexRequest.source(builder));
+        assertThat(e.getMessage(), equalTo("key [settings] must be an object"));
+    }
+
     public static void assertMappingsEqual(Map<String, String> expected, Map<String, String> actual) throws IOException {
         assertEquals(expected.keySet(), actual.keySet());