Increment settings version when upgrading index (#34566)

When we upgrade an index, we set the settings version upgraded
setting. This should be considered a settings change, and therefore we
need to increment the settings version. This commit addresses that.

Author: jasontedor

server/src/main/java/org/elasticsearch/cluster/metadata/MetaDataUpdateSettingsService.java

@@ -259,12 +259,16 @@ public ClusterState execute(ClusterState currentState) {
                     IndexMetaData indexMetaData = metaDataBuilder.get(index);
                     if (indexMetaData != null) {
                         if (Version.CURRENT.equals(indexMetaData.getCreationVersion()) == false) {
-                            // No reason to pollute the settings, we didn't really upgrade anything
-                            metaDataBuilder.put(IndexMetaData.builder(indexMetaData)
-                                            .settings(Settings.builder().put(indexMetaData.getSettings())
-                                                            .put(IndexMetaData.SETTING_VERSION_UPGRADED, entry.getValue().v1())
-                                            )
-                            );
+                            // no reason to pollute the settings, we didn't really upgrade anything
+                            metaDataBuilder.put(
+                                    IndexMetaData
+                                            .builder(indexMetaData)
+                                            .settings(
+                                                    Settings
+                                                            .builder()
+                                                            .put(indexMetaData.getSettings())
+                                                            .put(IndexMetaData.SETTING_VERSION_UPGRADED, entry.getValue().v1()))
+                                            .settingsVersion(1 + indexMetaData.getSettingsVersion()));
                         }
                     }
                 }

server/src/test/java/org/elasticsearch/cluster/metadata/UpgradeIndexSettingsIT.java

@@ -0,0 +1,50 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.cluster.metadata;
+
+import org.elasticsearch.Version;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.test.ESSingleNodeTestCase;
+
+import static org.hamcrest.Matchers.equalTo;
+
+public class UpgradeIndexSettingsIT extends ESSingleNodeTestCase {
+
+    @Override
+    protected boolean forbidPrivateIndexSettings() {
+        return false;
+    }
+
+    public void testSettingsVersion() {
+        createIndex(
+                "test",
+                Settings
+                        .builder()
+                        .put(IndexMetaData.SETTING_INDEX_VERSION_CREATED.getKey(), Version.CURRENT.minimumIndexCompatibilityVersion())
+                        .build());
+        final long settingsVersion =
+                client().admin().cluster().prepareState().get().getState().metaData().index("test").getSettingsVersion();
+        client().admin().indices().prepareUpgrade("test").get();
+        assertThat(
+                client().admin().cluster().prepareState().get().getState().metaData().index("test").getSettingsVersion(),
+                equalTo(1 + settingsVersion));
+    }
+
+}