Remove deprecated Plugin#onModule extension points (#37866)

Removes some guice index level extension point marked as @deprecated since at
least 6.0. They served as a signpost for plugin authors upgrading from 2.x but
this shouldn't be relevant in 7.0 anymore.

Author: Christoph Büscher

server/src/main/java/org/elasticsearch/plugins/Plugin.java

@@ -19,10 +19,8 @@
 
 package org.elasticsearch.plugins;
 
-import org.elasticsearch.action.ActionModule;
 import org.elasticsearch.bootstrap.BootstrapCheck;
 import org.elasticsearch.client.Client;
-import org.elasticsearch.cluster.ClusterModule;
 import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.cluster.metadata.IndexTemplateMetaData;
@@ -32,22 +30,15 @@
 import org.elasticsearch.common.inject.Module;
 import org.elasticsearch.common.io.stream.NamedWriteable;
 import org.elasticsearch.common.io.stream.NamedWriteableRegistry;
-import org.elasticsearch.common.network.NetworkModule;
 import org.elasticsearch.common.settings.Setting;
 import org.elasticsearch.common.settings.SettingUpgrader;
 import org.elasticsearch.common.settings.Settings;
-import org.elasticsearch.common.settings.SettingsModule;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
 import org.elasticsearch.common.xcontent.XContentParser;
-import org.elasticsearch.discovery.DiscoveryModule;
 import org.elasticsearch.env.Environment;
 import org.elasticsearch.env.NodeEnvironment;
 import org.elasticsearch.index.IndexModule;
-import org.elasticsearch.indices.analysis.AnalysisModule;
-import org.elasticsearch.repositories.RepositoriesModule;
-import org.elasticsearch.script.ScriptModule;
 import org.elasticsearch.script.ScriptService;
-import org.elasticsearch.search.SearchModule;
 import org.elasticsearch.threadpool.ExecutorBuilder;
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.watcher.ResourceWatcherService;
@@ -77,9 +68,6 @@
  * <li>{@link SearchPlugin}
  * <li>{@link ReloadablePlugin}
  * </ul>
- * <p>In addition to extension points this class also declares some {@code @Deprecated} {@code public final void onModule} methods. These
- * methods should cause any extensions of {@linkplain Plugin} that used the pre-5.x style extension syntax to fail to build and point the
- * plugin author at the new extension syntax. We hope that these make the process of upgrading a plugin from 2.x to 5.x only mildly painful.
  */
 public abstract class Plugin implements Closeable {
 
@@ -257,95 +245,4 @@ public List<ExecutorBuilder<?>> getExecutorBuilders(Settings settings) {
     public void close() throws IOException {
 
     }
-
-    /**
-     * Old-style guice index level extension point. {@code @Deprecated} and {@code final} to act as a signpost for plugin authors upgrading
-     * from 2.x.
-     *
-     * @deprecated use #onIndexModule instead
-     */
-    @Deprecated
-    public final void onModule(IndexModule indexModule) {}
-
-
-    /**
-     * Old-style guice settings extension point. {@code @Deprecated} and {@code final} to act as a signpost for plugin authors upgrading
-     * from 2.x.
-     *
-     * @deprecated use #getSettings and #getSettingsFilter instead
-     */
-    @Deprecated
-    public final void onModule(SettingsModule settingsModule) {}
-
-    /**
-     * Old-style guice scripting extension point. {@code @Deprecated} and {@code final} to act as a signpost for plugin authors upgrading
-     * from 2.x.
-     *
-     * @deprecated implement {@link ScriptPlugin} instead
-     */
-    @Deprecated
-    public final void onModule(ScriptModule module) {}
-
-    /**
-     * Old-style analysis extension point. {@code @Deprecated} and {@code final} to act as a signpost for plugin authors upgrading
-     * from 2.x.
-     *
-     * @deprecated implement {@link AnalysisPlugin} instead
-     */
-    @Deprecated
-    public final void onModule(AnalysisModule module) {}
-
-    /**
-     * Old-style action extension point. {@code @Deprecated} and {@code final} to act as a signpost for plugin authors upgrading
-     * from 2.x.
-     *
-     * @deprecated implement {@link ActionPlugin} instead
-     */
-    @Deprecated
-    public final void onModule(ActionModule module) {}
-
-    /**
-     * Old-style search extension point. {@code @Deprecated} and {@code final} to act as a signpost for plugin authors upgrading
-     * from 2.x.
-     *
-     * @deprecated implement {@link SearchPlugin} instead
-     */
-    @Deprecated
-    public final void onModule(SearchModule module) {}
-
-    /**
-     * Old-style network extension point. {@code @Deprecated} and {@code final} to act as a signpost for plugin authors upgrading
-     * from 2.x.
-     *
-     * @deprecated implement {@link NetworkPlugin} instead
-     */
-    @Deprecated
-    public final void onModule(NetworkModule module) {}
-
-    /**
-     * Old-style snapshot/restore extension point. {@code @Deprecated} and {@code final} to act as a signpost for plugin authors upgrading
-     * from 2.x.
-     *
-     * @deprecated implement {@link RepositoryPlugin} instead
-     */
-    @Deprecated
-    public final void onModule(RepositoriesModule module) {}
-
-    /**
-     * Old-style cluster extension point. {@code @Deprecated} and {@code final} to act as a signpost for plugin authors upgrading
-     * from 2.x.
-     *
-     * @deprecated implement {@link ClusterPlugin} instead
-     */
-    @Deprecated
-    public final void onModule(ClusterModule module) {}
-
-    /**
-     * Old-style discovery extension point. {@code @Deprecated} and {@code final} to act as a signpost for plugin authors upgrading
-     * from 2.x.
-     *
-     * @deprecated implement {@link DiscoveryPlugin} instead
-     */
-    @Deprecated
-    public final void onModule(DiscoveryModule module) {}
 }