Re-define index.mapper.dynamic setting in 8.x

docs/changelog/109341.yaml

@@ -0,0 +1,5 @@
+pr: 109341
+summary: Re-define `index.mapper.dynamic` setting in 8.x for a better 7.x to 8.x upgrade if this setting is used.
+area: Mapping
+type: bug
+issues: []

qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/UpgradeWithOldIndexSettingsIT.java

@@ -0,0 +1,82 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+package org.elasticsearch.upgrades;
+
+import com.carrotsearch.randomizedtesting.annotations.Name;
+
+import org.elasticsearch.client.Request;
+import org.elasticsearch.client.ResponseException;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.support.XContentMapValues;
+import org.elasticsearch.test.cluster.ElasticsearchCluster;
+import org.elasticsearch.test.cluster.FeatureFlag;
+import org.elasticsearch.test.cluster.local.LocalClusterConfigProvider;
+import org.elasticsearch.test.cluster.local.distribution.DistributionType;
+import org.junit.ClassRule;
+
+import java.io.IOException;
+
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.equalTo;
+
+public class UpgradeWithOldIndexSettingsIT extends ParameterizedFullClusterRestartTestCase {
+
+    protected static LocalClusterConfigProvider clusterConfig = c -> {};
+
+    @ClassRule
+    public static ElasticsearchCluster cluster = ElasticsearchCluster.local()
+        .distribution(DistributionType.DEFAULT)
+        .version(getOldClusterTestVersion())
+        .nodes(2)
+        .setting("xpack.security.enabled", "false")
+        .feature(FeatureFlag.FAILURE_STORE_ENABLED)
+        .apply(() -> clusterConfig)
+        .build();
+
+    @Override
+    protected ElasticsearchCluster getUpgradeCluster() {
+        return cluster;
+    }
+
+    public UpgradeWithOldIndexSettingsIT(@Name("cluster") FullClusterRestartUpgradeStatus upgradeStatus) {
+        super(upgradeStatus);
+    }
+
+    public void testMapperDynamicIndexSetting() throws IOException {
+        assumeTrue(
+            "Setting deprecated in 6.x, but remained in 7.x and is no longer defined in 8.x",
+            getOldClusterTestVersion().before("8.0.0")
+        );
+        String indexName = "my-index";
+        if (isRunningAgainstOldCluster()) {
+            createIndex(indexName);
+
+            var request = new Request("PUT", "/my-index/_settings");
+            request.setJsonEntity(org.elasticsearch.common.Strings.toString(Settings.builder().put("index.mapper.dynamic", true).build()));
+            request.setOptions(
+                expectWarnings(
+                    "[index.mapper.dynamic] setting was deprecated in Elasticsearch and will be removed in a future release! "
+                        + "See the breaking changes documentation for the next major version."
+                )
+            );
+            assertOK(client().performRequest(request));
+        } else {
+            var indexSettings = getIndexSettings(indexName);
+            assertThat(XContentMapValues.extractValue(indexName + ".settings.index.mapper.dynamic", indexSettings), equalTo("true"));
+            ensureGreen(indexName);
+            // New indices can never define the index.mapper.dynamic setting.
+            Exception e = expectThrows(
+                ResponseException.class,
+                () -> createIndex("my-index2", Settings.builder().put("index.mapper.dynamic", true).build())
+            );
+            assertThat(e.getMessage(), containsString("unknown setting [index.mapper.dynamic]"));
+        }
+    }
+
+}

qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/upgrades/UpgradeWithOldIndexSettingsIT.java

@@ -22,6 +22,8 @@
 import java.util.Map;
 
 import static org.elasticsearch.rest.action.search.RestSearchAction.TOTAL_HITS_AS_INT_PARAM;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.is;
 
 public class UpgradeWithOldIndexSettingsIT extends AbstractRollingUpgradeTestCase {
@@ -102,6 +104,38 @@ public void testOldIndexSettings() throws Exception {
         }
     }
 
+    public void testMapperDynamicIndexSetting() throws IOException {
+        assumeTrue(
+            "Setting deprecated in 6.x, but remained in 7.x and is no longer defined in 8.x",
+            getOldClusterTestVersion().before("8.0.0")
+        );
+        String indexName = "my-index";
+        if (isOldCluster()) {
+            createIndex(indexName);
+            Request request = new Request("PUT", "/" + indexName + "/_settings");
+            request.setJsonEntity(org.elasticsearch.common.Strings.toString(Settings.builder().put("index.mapper.dynamic", true).build()));
+            request.setOptions(
+                expectWarnings(
+                    "[index.mapper.dynamic] setting was deprecated in Elasticsearch and will be removed in a future release! "
+                        + "See the breaking changes documentation for the next major version."
+                )
+            );
+            assertOK(client().performRequest(request));
+        } else {
+            if (isUpgradedCluster()) {
+                var indexSettings = getIndexSettings(indexName);
+                assertThat(XContentMapValues.extractValue(indexName + ".settings.index.mapper.dynamic", indexSettings), equalTo("true"));
+                ensureGreen(indexName);
+                // New indices can never define the index.mapper.dynamic setting.
+                Exception e = expectThrows(
+                    ResponseException.class,
+                    () -> createIndex("my-index2", Settings.builder().put("index.mapper.dynamic", true).build())
+                );
+                assertThat(e.getMessage(), containsString("unknown setting [index.mapper.dynamic]"));
+            }
+        }
+    }
+
     private void assertCount(String index, int countAtLeast) throws IOException {
         Request searchTestIndexRequest = new Request("POST", "/" + index + "/_search");
         searchTestIndexRequest.addParameter(TOTAL_HITS_AS_INT_PARAM, "true");

server/src/main/java/org/elasticsearch/common/settings/IndexScopedSettings.java

@@ -158,6 +158,7 @@ public final class IndexScopedSettings extends AbstractScopedSettings {
         MapperService.INDEX_MAPPING_DEPTH_LIMIT_SETTING,
         MapperService.INDEX_MAPPING_DIMENSION_FIELDS_LIMIT_SETTING,
         MapperService.INDEX_MAPPING_FIELD_NAME_LENGTH_LIMIT_SETTING,
+        MapperService.INDEX_MAPPER_DYNAMIC_SETTING,
         BitsetFilterCache.INDEX_LOAD_RANDOM_ACCESS_FILTERS_EAGERLY_SETTING,
         IndexModule.INDEX_STORE_TYPE_SETTING,
         IndexModule.INDEX_STORE_PRE_LOAD_SETTING,

server/src/main/java/org/elasticsearch/index/mapper/MapperService.java

@@ -21,6 +21,7 @@
 import org.elasticsearch.common.xcontent.LoggingDeprecationHandler;
 import org.elasticsearch.common.xcontent.XContentHelper;
 import org.elasticsearch.core.Nullable;
+import org.elasticsearch.core.UpdateForV9;
 import org.elasticsearch.index.AbstractIndexComponent;
 import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.IndexVersion;
@@ -147,6 +148,19 @@ public boolean isAutoUpdate() {
         Property.Dynamic,
         Property.IndexScope
     );
+    /**
+     * Legacy index setting, kept for 7.x BWC compatibility. This setting has no effect in 8.x. Do not use.
+     * TODO: Remove in 9.0
+     */
+    @Deprecated
+    @UpdateForV9
+    public static final Setting<Boolean> INDEX_MAPPER_DYNAMIC_SETTING = Setting.boolSetting(
+        "index.mapper.dynamic",
+        true,
+        Property.Dynamic,
+        Property.IndexScope,
+        Property.IndexSettingDeprecatedInV7AndRemovedInV8
+    );
 
     private final IndexAnalyzers indexAnalyzers;
     private final MappingParser mappingParser;