Remove xpack actions for the flattened field. (#53076)

The current consensus is that we don't need info actions for smaller items like
field mappers. We can also remove the usage action since the cluster stats API
now tracks information about mappings, like what field types are defined.

docs/reference/rest-api/info.asciidoc

@@ -75,10 +75,6 @@ Example response:
           "available" : true,
           "enabled" : true
       },
-      "flattened" : {
-         "available" : true,
-         "enabled" : true
-      },
       "frozen_indices" : {
          "available" : true,
          "enabled" : true

docs/reference/rest-api/usage.asciidoc

@@ -242,11 +242,6 @@ GET /_xpack/usage
     "available" : true,
     "enabled" : true
   },
-  "flattened" : {
-    "available" : true,
-    "enabled" : true,
-    "field_count" : 0
-  },
   "vectors" : {
     "available" : true,
     "enabled" : true,
@@ -289,4 +284,4 @@ GET /_xpack/usage
 // 3. Ignore the contents of the `slm` object because it might contain policies
 // 4. All of the numbers and strings on the right hand side of *every* field in
 //    the response are ignored. So we're really only asserting things about the
-//    the shape of this response, not the values in it.
+//    the shape of this response, not the values in it.

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/XPackClientPlugin.java

@@ -38,7 +38,6 @@
 import org.elasticsearch.xpack.core.ccr.AutoFollowMetadata;
 import org.elasticsearch.xpack.core.deprecation.DeprecationInfoAction;
 import org.elasticsearch.xpack.core.eql.EqlFeatureSetUsage;
-import org.elasticsearch.xpack.core.flattened.FlattenedFeatureSetUsage;
 import org.elasticsearch.xpack.core.frozen.FrozenIndicesFeatureSetUsage;
 import org.elasticsearch.xpack.core.frozen.action.FreezeIndexAction;
 import org.elasticsearch.xpack.core.graph.GraphFeatureSetUsage;
@@ -556,7 +555,6 @@ public List<NamedWriteableRegistry.Entry> getNamedWriteables() {
                 new NamedWriteableRegistry.Entry(Task.Status.class, TransformField.TASK_NAME, TransformState::new),
                 new NamedWriteableRegistry.Entry(PersistentTaskState.class, TransformField.TASK_NAME, TransformState::new),
                 new NamedWriteableRegistry.Entry(SyncConfig.class, TransformField.TIME_BASED_SYNC.getPreferredName(), TimeSyncConfig::new),
-                new NamedWriteableRegistry.Entry(XPackFeatureSet.Usage.class, XPackField.FLATTENED, FlattenedFeatureSetUsage::new),
                 // Vectors
                 new NamedWriteableRegistry.Entry(XPackFeatureSet.Usage.class, XPackField.VECTORS, VectorsFeatureSetUsage::new),
                 // Voting Only Node

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/XPackField.java

@@ -42,7 +42,6 @@ public final class XPackField {
     /** Name constant for the transform feature. */
     public static final String TRANSFORM = "transform";
     /** Name constant for flattened fields. */
-    public static final String FLATTENED = "flattened";
     /** Name constant for the vectors feature. */
     public static final String VECTORS = "vectors";
     /** Name constant for the voting-only-node feature. */

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/action/XPackInfoFeatureAction.java

@@ -35,7 +35,6 @@ public class XPackInfoFeatureAction extends ActionType<XPackInfoFeatureResponse>
     public static final XPackInfoFeatureAction SNAPSHOT_LIFECYCLE = new XPackInfoFeatureAction(XPackField.SNAPSHOT_LIFECYCLE);
     public static final XPackInfoFeatureAction CCR = new XPackInfoFeatureAction(XPackField.CCR);
     public static final XPackInfoFeatureAction TRANSFORM = new XPackInfoFeatureAction(XPackField.TRANSFORM);
-    public static final XPackInfoFeatureAction FLATTENED = new XPackInfoFeatureAction(XPackField.FLATTENED);
     public static final XPackInfoFeatureAction VECTORS = new XPackInfoFeatureAction(XPackField.VECTORS);
     public static final XPackInfoFeatureAction VOTING_ONLY = new XPackInfoFeatureAction(XPackField.VOTING_ONLY);
     public static final XPackInfoFeatureAction FROZEN_INDICES = new XPackInfoFeatureAction(XPackField.FROZEN_INDICES);
@@ -45,7 +44,7 @@ public class XPackInfoFeatureAction extends ActionType<XPackInfoFeatureResponse>
 
     public static final List<XPackInfoFeatureAction> ALL = Arrays.asList(
         SECURITY, MONITORING, WATCHER, GRAPH, MACHINE_LEARNING, LOGSTASH, EQL, SQL, ROLLUP, INDEX_LIFECYCLE, SNAPSHOT_LIFECYCLE, CCR,
-        TRANSFORM, FLATTENED, VECTORS, VOTING_ONLY, FROZEN_INDICES, SPATIAL, ANALYTICS, ENRICH
+        TRANSFORM, VECTORS, VOTING_ONLY, FROZEN_INDICES, SPATIAL, ANALYTICS, ENRICH
     );
 
     private XPackInfoFeatureAction(String name) {

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/action/XPackUsageFeatureAction.java

@@ -35,7 +35,6 @@ public class XPackUsageFeatureAction extends ActionType<XPackUsageFeatureRespons
     public static final XPackUsageFeatureAction SNAPSHOT_LIFECYCLE = new XPackUsageFeatureAction(XPackField.SNAPSHOT_LIFECYCLE);
     public static final XPackUsageFeatureAction CCR = new XPackUsageFeatureAction(XPackField.CCR);
     public static final XPackUsageFeatureAction TRANSFORM = new XPackUsageFeatureAction(XPackField.TRANSFORM);
-    public static final XPackUsageFeatureAction FLATTENED = new XPackUsageFeatureAction(XPackField.FLATTENED);
     public static final XPackUsageFeatureAction VECTORS = new XPackUsageFeatureAction(XPackField.VECTORS);
     public static final XPackUsageFeatureAction VOTING_ONLY = new XPackUsageFeatureAction(XPackField.VOTING_ONLY);
     public static final XPackUsageFeatureAction FROZEN_INDICES = new XPackUsageFeatureAction(XPackField.FROZEN_INDICES);
@@ -44,7 +43,7 @@ public class XPackUsageFeatureAction extends ActionType<XPackUsageFeatureRespons
 
     public static final List<XPackUsageFeatureAction> ALL = Arrays.asList(
         SECURITY, MONITORING, WATCHER, GRAPH, MACHINE_LEARNING, LOGSTASH, EQL, SQL, ROLLUP, INDEX_LIFECYCLE, SNAPSHOT_LIFECYCLE, CCR,
-        TRANSFORM, FLATTENED, VECTORS, VOTING_ONLY, FROZEN_INDICES, SPATIAL, ANALYTICS
+        TRANSFORM, VECTORS, VOTING_ONLY, FROZEN_INDICES, SPATIAL, ANALYTICS
     );
 
     private XPackUsageFeatureAction(String name) {

x-pack/plugin/mapper-flattened/src/main/java/org/elasticsearch/xpack/flattened/FlattenedMapperPlugin.java

@@ -6,26 +6,19 @@
 
 package org.elasticsearch.xpack.flattened;
 
-import org.elasticsearch.action.ActionRequest;
-import org.elasticsearch.action.ActionResponse;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.index.mapper.Mapper;
-import org.elasticsearch.plugins.ActionPlugin;
 import org.elasticsearch.plugins.MapperPlugin;
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.xpack.core.XPackSettings;
-import org.elasticsearch.xpack.core.action.XPackInfoFeatureAction;
-import org.elasticsearch.xpack.core.action.XPackUsageFeatureAction;
 import org.elasticsearch.xpack.flattened.mapper.FlatObjectFieldMapper;
 
-import java.util.Arrays;
-import java.util.List;
 import java.util.Map;
 
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.singletonMap;
 
-public class FlattenedMapperPlugin extends Plugin implements MapperPlugin, ActionPlugin {
+public class FlattenedMapperPlugin extends Plugin implements MapperPlugin {
 
     protected final boolean enabled;
 
@@ -40,11 +33,4 @@ public Map<String, Mapper.TypeParser> getMappers() {
         }
         return singletonMap(FlatObjectFieldMapper.CONTENT_TYPE, new FlatObjectFieldMapper.TypeParser());
     }
-
-    @Override
-    public List<ActionHandler<? extends ActionRequest, ? extends ActionResponse>> getActions() {
-        return Arrays.asList(
-            new ActionHandler<>(XPackUsageFeatureAction.FLATTENED, FlattenedUsageTransportAction.class),
-            new ActionHandler<>(XPackInfoFeatureAction.FLATTENED, FlattenedInfoTransportAction.class));
-    }
 }