Tidy up deprecation code.

client/rest-high-level/src/main/java/org/elasticsearch/client/migration/DeprecationInfoResponse.java

@@ -59,7 +59,7 @@ public List<DeprecationIssue> getMlSettingsIssues() {
 
     private static List<DeprecationIssue> parseDeprecationIssues(XContentParser parser) throws IOException {
         List<DeprecationIssue> issues = new ArrayList<>();
-        XContentParser.Token token = null;
+        XContentParser.Token token;
         while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
             if (token == XContentParser.Token.START_OBJECT) {
                 issues.add(DeprecationIssue.PARSER.parse(parser, null));
@@ -116,8 +116,7 @@ public int hashCode() {
 
     @Override
     public String toString() {
-        return clusterSettingsIssues.toString() + ":" + nodeSettingsIssues.toString() + ":" + indexSettingsIssues.toString() +
-            ":" + mlSettingsIssues.toString();
+        return clusterSettingsIssues + ":" + nodeSettingsIssues + ":" + indexSettingsIssues + ":" + mlSettingsIssues;
     }
 
     /**
@@ -156,10 +155,10 @@ public String toString() {
             }
         }
 
-        private Level level;
-        private String message;
-        private String url;
-        private String details;
+        private final Level level;
+        private final String message;
+        private final String url;
+        private final String details;
 
         public DeprecationIssue(Level level, String message, String url, @Nullable String details) {
             this.level = level;

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

@@ -59,15 +59,10 @@ public String toString() {
         }
     }
 
-    private Level level;
-    private String message;
-    private String url;
-    private String details;
-
-    // pkg-private for tests
-    DeprecationIssue() {
-
-    }
+    private final Level level;
+    private final String message;
+    private final String url;
+    private final String details;
 
     public DeprecationIssue(Level level, String message, String url, @Nullable String details) {
         this.level = level;

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

@@ -52,7 +52,7 @@ public void writeTo(StreamOutput out) throws IOException {
     }
 
     public static class NodeResponse extends BaseNodeResponse {
-        private List<DeprecationIssue> deprecationIssues;
+        private final List<DeprecationIssue> deprecationIssues;
 
         public NodeResponse(StreamInput in) throws IOException {
             super(in);

x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/deprecation/DeprecationChecksTests.java

@@ -8,7 +8,6 @@
 
 import org.elasticsearch.test.ESTestCase;
 
-import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.function.Supplier;
@@ -17,7 +16,7 @@
 
 public class DeprecationChecksTests extends ESTestCase {
 
-    public void testFilterChecks() throws IOException {
+    public void testFilterChecks() {
         DeprecationIssue issue = DeprecationIssueTests.createTestInstance();
         int numChecksPassed = randomIntBetween(0, 5);
         int numChecksFailed = 10 - numChecksPassed;

x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/deprecation/DeprecationInfoActionResponseTests.java

@@ -8,7 +8,6 @@
 
 import org.elasticsearch.ElasticsearchStatusException;
 import org.elasticsearch.Version;
-import org.elasticsearch.action.support.IndicesOptions;
 import org.elasticsearch.cluster.ClusterName;
 import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.metadata.IndexMetadata;
@@ -23,8 +22,6 @@
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.indices.TestIndexNameExpressionResolver;
 import org.elasticsearch.test.AbstractWireSerializingTestCase;
-import org.elasticsearch.xpack.core.ml.datafeed.DatafeedConfig;
-import org.elasticsearch.xpack.core.ml.datafeed.DatafeedConfigTests;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -85,10 +82,7 @@ public void testFrom() throws IOException {
         DiscoveryNode discoveryNode = DiscoveryNode.createLocal(Settings.EMPTY,
             new TransportAddress(TransportAddress.META_ADDRESS, 9300), "test");
         ClusterState state = ClusterState.builder(ClusterName.DEFAULT).metadata(metadata).build();
-        List<DatafeedConfig> datafeeds = Collections.singletonList(DatafeedConfigTests.createRandomizedDatafeedConfig("foo"));
         IndexNameExpressionResolver resolver = TestIndexNameExpressionResolver.newInstance();
-        IndicesOptions indicesOptions = IndicesOptions.fromOptions(false, false,
-            true, true);
         boolean clusterIssueFound = randomBoolean();
         boolean nodeIssueFound = randomBoolean();
         boolean indexIssueFound = randomBoolean();

x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/IndexDeprecationChecks.java

@@ -9,27 +9,16 @@
 
 import org.elasticsearch.Version;
 import org.elasticsearch.cluster.metadata.IndexMetadata;
-import org.elasticsearch.cluster.metadata.MappingMetadata;
 import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.xpack.core.deprecation.DeprecationIssue;
 
 import java.util.Locale;
-import java.util.Map;
-import java.util.function.BiConsumer;
 
 /**
  * Index-specific deprecation checks
  */
 public class IndexDeprecationChecks {
 
-    private static void fieldLevelMappingIssue(IndexMetadata indexMetadata, BiConsumer<MappingMetadata, Map<String, Object>> checker) {
-        MappingMetadata mmd = indexMetadata.mapping();
-        if (mmd != null) {
-            Map<String, Object> sourceAsMap = mmd.sourceAsMap();
-            checker.accept(mmd, sourceAsMap);
-        }
-    }
-
     static DeprecationIssue oldIndicesCheck(IndexMetadata indexMetadata) {
         Version createdWith = indexMetadata.getCreationVersion();
         if (createdWith.before(Version.V_7_0_0)) {

x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/NodeDeprecationChecks.java

@@ -15,93 +15,9 @@
 import org.elasticsearch.xpack.core.deprecation.DeprecationIssue;
 
 import java.util.Locale;
-import java.util.function.BiFunction;
 
 public class NodeDeprecationChecks {
 
-    private static DeprecationIssue checkDeprecatedSetting(
-        final Settings settings,
-        final PluginsAndModules pluginsAndModules,
-        final Setting<?> deprecatedSetting,
-        final Setting<?> replacementSetting,
-        final String url
-    ) {
-        return checkDeprecatedSetting(settings, pluginsAndModules, deprecatedSetting, replacementSetting, (v, s) -> v, url);
-    }
-
-    private static DeprecationIssue checkDeprecatedSetting(
-        final Settings settings,
-        final PluginsAndModules pluginsAndModules,
-        final Setting<?> deprecatedSetting,
-        final Setting<?> replacementSetting,
-        final BiFunction<String, Settings, String> replacementValue,
-        final String url
-    ) {
-        assert deprecatedSetting.isDeprecated() : deprecatedSetting;
-        if (deprecatedSetting.exists(settings) == false) {
-            return null;
-        }
-        final String deprecatedSettingKey = deprecatedSetting.getKey();
-        final String replacementSettingKey = replacementSetting.getKey();
-        final String value = deprecatedSetting.get(settings).toString();
-        final String message = String.format(
-            Locale.ROOT,
-            "setting [%s] is deprecated in favor of setting [%s]",
-            deprecatedSettingKey,
-            replacementSettingKey);
-        final String details = String.format(
-            Locale.ROOT,
-            "the setting [%s] is currently set to [%s], instead set [%s] to [%s]",
-            deprecatedSettingKey,
-            value,
-            replacementSettingKey,
-            replacementValue.apply(value, settings));
-        return new DeprecationIssue(DeprecationIssue.Level.CRITICAL, message, url, details);
-    }
-
-    private static DeprecationIssue checkDeprecatedSetting(
-        final Settings settings,
-        final PluginsAndModules pluginsAndModules,
-        final Setting<?> deprecatedSetting,
-        final Setting.AffixSetting<?> replacementSetting,
-        final String star,
-        final String url
-    ) {
-        return checkDeprecatedSetting(settings, pluginsAndModules, deprecatedSetting, replacementSetting, (v, s) -> v, star, url);
-    }
-
-    private static DeprecationIssue checkDeprecatedSetting(
-        final Settings settings,
-        final PluginsAndModules pluginsAndModules,
-        final Setting<?> deprecatedSetting,
-        final Setting.AffixSetting<?> replacementSetting,
-        final BiFunction<String, Settings, String> replacementValue,
-        final String star,
-        final String url
-    ) {
-        assert deprecatedSetting.isDeprecated() : deprecatedSetting;
-        if (deprecatedSetting.exists(settings) == false) {
-            return null;
-        }
-        final String deprecatedSettingKey = deprecatedSetting.getKey();
-        final String replacementSettingKey = replacementSetting.getKey();
-        final String value = deprecatedSetting.get(settings).toString();
-        final String message = String.format(
-            Locale.ROOT,
-            "setting [%s] is deprecated in favor of grouped setting [%s]",
-            deprecatedSettingKey,
-            replacementSettingKey);
-        final String details = String.format(
-            Locale.ROOT,
-            "the setting [%s] is currently set to [%s], instead set [%s] to [%s] where * is %s",
-            deprecatedSettingKey,
-            value,
-            replacementSettingKey,
-            replacementValue.apply(value, settings),
-            star);
-        return new DeprecationIssue(DeprecationIssue.Level.CRITICAL, message, url, details);
-    }
-
     static DeprecationIssue checkRemovedSetting(final Settings settings, final Setting<?> removedSetting, final String url) {
         if (removedSetting.exists(settings) == false) {
             return null;