Convert cluster state "customs" to Map (#87265)

The pluggable portions of in memory cluster state are held within an
ImmutableOpenMap. This commit converts that to a Map. Note that the diff
format is the same for immutableopenmap and jdk map, so no bwc logic is
necessary.

relates #86239

Author: rjernst

server/src/internalClusterTest/java/org/elasticsearch/cluster/ClusterStateDiffIT.java

@@ -371,7 +371,7 @@ private interface RandomClusterPart<T> {
         /**
          * Returns list of parts from metadata
          */
-        ImmutableOpenMap<String, T> parts(ClusterState clusterState);
+        Map<String, T> parts(ClusterState clusterState);
 
         /**
          * Puts the part back into metadata
@@ -401,7 +401,7 @@ private interface RandomClusterPart<T> {
      */
     private <T> ClusterState randomClusterStateParts(ClusterState clusterState, String prefix, RandomClusterPart<T> randomPart) {
         ClusterState.Builder builder = ClusterState.builder(clusterState);
-        ImmutableOpenMap<String, T> parts = randomPart.parts(clusterState);
+        Map<String, T> parts = randomPart.parts(clusterState);
         int partCount = parts.size();
         if (partCount > 0) {
             List<String> randomParts = randomSubsetOf(
@@ -688,7 +688,7 @@ private ClusterState.Builder randomClusterStateCustoms(final ClusterState cluste
         return ClusterState.builder(randomClusterStateParts(clusterState, "custom", new RandomClusterPart<ClusterState.Custom>() {
 
             @Override
-            public ImmutableOpenMap<String, ClusterState.Custom> parts(ClusterState clusterState) {
+            public Map<String, ClusterState.Custom> parts(ClusterState clusterState) {
                 return clusterState.customs();
             }
 

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

@@ -151,7 +151,7 @@ default boolean isPrivate() {
 
     private final ClusterBlocks blocks;
 
-    private final ImmutableOpenMap<String, Custom> customs;
+    private final Map<String, Custom> customs;
 
     private final ClusterName clusterName;
 
@@ -183,7 +183,7 @@ public ClusterState(
         RoutingTable routingTable,
         DiscoveryNodes nodes,
         ClusterBlocks blocks,
-        ImmutableOpenMap<String, Custom> customs,
+        Map<String, Custom> customs,
         boolean wasReadFromDiff,
         @Nullable RoutingNodes routingNodes
     ) {
@@ -281,11 +281,11 @@ public ClusterBlocks getBlocks() {
         return blocks;
     }
 
-    public ImmutableOpenMap<String, Custom> customs() {
+    public Map<String, Custom> customs() {
         return this.customs;
     }
 
-    public ImmutableOpenMap<String, Custom> getCustoms() {
+    public Map<String, Custom> getCustoms() {
         return this.customs;
     }
 
@@ -698,7 +698,7 @@ public Builder removeCustom(String type) {
             return this;
         }
 
-        public Builder customs(ImmutableOpenMap<String, Custom> customs) {
+        public Builder customs(Map<String, Custom> customs) {
             customs.forEach((key, value) -> Objects.requireNonNull(value, key));
             this.customs.putAllFromMap(customs);
             return this;
@@ -814,7 +814,7 @@ private static class ClusterStateDiff implements Diff<ClusterState> {
 
         private final Diff<ClusterBlocks> blocks;
 
-        private final Diff<ImmutableOpenMap<String, Custom>> customs;
+        private final Diff<Map<String, Custom>> customs;
 
         ClusterStateDiff(ClusterState before, ClusterState after) {
             fromUuid = before.stateUUID;
@@ -837,7 +837,7 @@ private static class ClusterStateDiff implements Diff<ClusterState> {
             nodes = DiscoveryNodes.readDiffFrom(in, localNode);
             metadata = Metadata.readDiffFrom(in);
             blocks = ClusterBlocks.readDiffFrom(in);
-            customs = DiffableUtils.readImmutableOpenMapDiff(in, DiffableUtils.getStringKeySerializer(), CUSTOM_VALUE_SERIALIZER);
+            customs = DiffableUtils.readJdkMapDiff(in, DiffableUtils.getStringKeySerializer(), CUSTOM_VALUE_SERIALIZER);
             if (in.getVersion().before(Version.V_8_0_0)) {
                 in.readVInt(); // used to be minimumMasterNodesOnPublishingMaster, which was used in 7.x for BWC with 6.x
             }

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

@@ -145,7 +145,7 @@ public ClusterState deleteIndices(ClusterState currentState, Set<Index> indices)
         ClusterBlocks blocks = clusterBlocksBuilder.build();
 
         // update snapshot restore entries
-        ImmutableOpenMap<String, ClusterState.Custom> customs = currentState.getCustoms();
+        Map<String, ClusterState.Custom> customs = currentState.getCustoms();
         final RestoreInProgress restoreInProgress = currentState.custom(RestoreInProgress.TYPE, RestoreInProgress.EMPTY);
         RestoreInProgress updatedRestoreInProgress = RestoreService.updateRestoreStateWithDeletedIndices(restoreInProgress, indices);
         if (updatedRestoreInProgress != restoreInProgress) {

server/src/main/java/org/elasticsearch/cluster/routing/allocation/RoutingAllocation.java

@@ -20,7 +20,6 @@
 import org.elasticsearch.cluster.routing.ShardRouting;
 import org.elasticsearch.cluster.routing.allocation.decider.AllocationDeciders;
 import org.elasticsearch.cluster.routing.allocation.decider.Decision;
-import org.elasticsearch.common.collect.ImmutableOpenMap;
 import org.elasticsearch.core.Nullable;
 import org.elasticsearch.index.shard.ShardId;
 import org.elasticsearch.snapshots.RestoreService.RestoreInProgressUpdater;
@@ -188,7 +187,7 @@ public <T extends ClusterState.Custom> T custom(String key) {
         return (T) clusterState.customs().get(key);
     }
 
-    public ImmutableOpenMap<String, ClusterState.Custom> getCustoms() {
+    public Map<String, ClusterState.Custom> getCustoms() {
         return clusterState.getCustoms();
     }
 

server/src/main/java/org/elasticsearch/common/io/stream/VersionedNamedWriteable.java

@@ -9,9 +9,9 @@
 package org.elasticsearch.common.io.stream;
 
 import org.elasticsearch.Version;
-import org.elasticsearch.common.collect.ImmutableOpenMap;
 
 import java.io.IOException;
+import java.util.Map;
 
 /**
  * A {@link NamedWriteable} that has a minimum version associated with it.
@@ -49,8 +49,7 @@ static <T extends VersionedNamedWriteable> boolean shouldSerialize(final StreamO
      * @param customs map of customs
      * @param <T>     type of customs in map
      */
-    static <T extends VersionedNamedWriteable> void writeVersionedWritables(StreamOutput out, ImmutableOpenMap<String, T> customs)
-        throws IOException {
+    static <T extends VersionedNamedWriteable> void writeVersionedWritables(StreamOutput out, Map<String, T> customs) throws IOException {
         // filter out custom states not supported by the other node
         int numberOfCustoms = 0;
         for (final T value : customs.values()) {