Address review comments

Author: alexey-ivanov-es

server/src/main/java/org/elasticsearch/cluster/ClusterState.java

@@ -1365,7 +1365,6 @@ private static class ClusterStateDiff implements Diff<ClusterState> {
                 COMPATIBILITY_VERSIONS_VALUE_SERIALIZER
             );
             features = after.clusterFeatures.diff(before.clusterFeatures);
-
             metadata = after.metadata.diff(before.metadata);
             blocks = after.blocks.diff(before.blocks);
             customs = DiffableUtils.diff(before.customs, after.customs, DiffableUtils.getStringKeySerializer(), CUSTOM_VALUE_SERIALIZER);

server/src/main/java/org/elasticsearch/cluster/DiffableUtils.java

@@ -104,8 +104,8 @@ public static <K, T, M extends Map<K, T>> MapDiff<K, T, M> emptyDiff() {
      */
     @SuppressWarnings("unchecked")
     public static <K, T extends Diffable<T>, T1 extends T, T2 extends T, M extends Map<K, T>> MapDiff<K, T, M> merge(
-        MapDiff<K, T1, ? extends Map<K, T1>> diff1,
-        MapDiff<K, T2, ? extends Map<K, T2>> diff2,
+        MapDiff<K, T1, ? extends ImmutableOpenMap<K, T1>> diff1,
+        MapDiff<K, T2, ? extends ImmutableOpenMap<K, T2>> diff2,
         KeySerializer<K> keySerializer
     ) {
         return merge(diff1, diff2, keySerializer, DiffableValueSerializer.getWriteOnlyInstance());
@@ -116,8 +116,8 @@ public static <K, T extends Diffable<T>, T1 extends T, T2 extends T, M extends M
      */
     @SuppressWarnings("unchecked")
     public static <K, T, T1 extends T, T2 extends T, M extends Map<K, T>> MapDiff<K, T, M> merge(
-        MapDiff<K, T1, ? extends Map<K, T1>> diff1,
-        MapDiff<K, T2, ? extends Map<K, T2>> diff2,
+        MapDiff<K, T1, ? extends ImmutableOpenMap<K, T1>> diff1,
+        MapDiff<K, T2, ? extends ImmutableOpenMap<K, T2>> diff2,
         KeySerializer<K> keySerializer,
         ValueSerializer<K, T> valueSerializer
     ) {
@@ -130,7 +130,7 @@ public static <K, T, T1 extends T, T2 extends T, M extends Map<K, T>> MapDiff<K,
             mapEntries(diff1.getUpserts(), val -> (T) val),
             mapEntries(diff2.getUpserts(), val -> (T) val)
         ).toList();
-        return new MapDiff<>(keySerializer, valueSerializer, deletes, diffs, upserts, DiffableUtils::createImmutableMapBuilder);
+        return new MapDiff<K, T, M>(keySerializer, valueSerializer, deletes, diffs, upserts, DiffableUtils::createImmutableMapBuilder);
     }
 
     /**

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

@@ -36,6 +36,7 @@
 import org.elasticsearch.common.xcontent.ChunkedToXContentHelper;
 import org.elasticsearch.common.xcontent.XContentHelper;
 import org.elasticsearch.common.xcontent.XContentParserUtils;
+import org.elasticsearch.core.FixForMultiProject;
 import org.elasticsearch.core.Nullable;
 import org.elasticsearch.index.Index;
 import org.elasticsearch.index.IndexMode;
@@ -2058,6 +2059,7 @@ static boolean assertDataStreams(Map<String, IndexMetadata> indices, DataStreamM
             return true;
         }
 
+        @FixForMultiProject(description = "Remove reading reserved_state and settings")
         public static ProjectMetadata fromXContent(XContentParser parser) throws IOException {
             XContentParser.Token token = parser.currentToken();
             if (token == null) {
@@ -2078,6 +2080,7 @@ public static ProjectMetadata fromXContent(XContentParser parser) throws IOExcep
                     }
                 } else if (token == XContentParser.Token.START_OBJECT) {
                     switch (currentFieldName) {
+                        // Remove this
                         case "reserved_state" -> {
                             while (parser.nextToken() != XContentParser.Token.END_OBJECT) {
                                 ReservedStateMetadata.fromXContent(parser);
@@ -2093,6 +2096,7 @@ public static ProjectMetadata fromXContent(XContentParser parser) throws IOExcep
                                 projectBuilder.put(IndexTemplateMetadata.Builder.fromXContent(parser, parser.currentName()));
                             }
                         }
+                        // Remove this
                         case "settings" -> {
                             Settings.fromXContent(parser);
                         }

server/src/main/java/org/elasticsearch/cluster/project/ProjectStateRegistry.java

@@ -316,7 +316,7 @@ private Builder(ProjectStateRegistry original) {
             this.projectsMarkedForDeletionGeneration = original.projectsMarkedForDeletionGeneration;
         }
 
-        private void modifyEntry(ProjectId projectId, Function<Entry, Entry> modifier) {
+        private void updateEntry(ProjectId projectId, Function<Entry, Entry> modifier) {
             Entry entry = projectsEntries.get(projectId);
             if (entry == null) {
                 entry = new Entry();
@@ -326,12 +326,12 @@ private void modifyEntry(ProjectId projectId, Function<Entry, Entry> modifier) {
         }
 
         public Builder putProjectSettings(ProjectId projectId, Settings settings) {
-            modifyEntry(projectId, entry -> entry.withSettings(settings));
+            updateEntry(projectId, entry -> entry.withSettings(settings));
             return this;
         }
 
         public Builder putReservedStateMetadata(ProjectId projectId, ReservedStateMetadata reservedStateMetadata) {
-            modifyEntry(projectId, entry -> entry.withReservedStateMetadata(reservedStateMetadata));
+            updateEntry(projectId, entry -> entry.withReservedStateMetadata(reservedStateMetadata));
             return this;
         }
 
@@ -397,10 +397,10 @@ public Entry withSettings(Settings settings) {
         }
 
         public Entry withReservedStateMetadata(ReservedStateMetadata reservedStateMetadata) {
-            ImmutableOpenMap<String, ReservedStateMetadata> build = ImmutableOpenMap.builder(this.reservedStateMetadata)
+            ImmutableOpenMap<String, ReservedStateMetadata> reservedStateMetadataMap = ImmutableOpenMap.builder(this.reservedStateMetadata)
                 .fPut(reservedStateMetadata.namespace(), reservedStateMetadata)
                 .build();
-            return new Entry(settings, build);
+            return new Entry(settings, reservedStateMetadataMap);
         }
 
         @Override