Expose some classes/members to plugins (#94541)

The stateless `ClusterCoordinationPlugin` needs access to a few private
or package-private classes and members. This commit makes the relevant
things protected or public.

server/src/main/java/org/elasticsearch/gateway/ClusterStateUpdaters.java

@@ -28,7 +28,7 @@ import static org.elasticsearch.gateway.GatewayService.STATE_NOT_RECOVERED_BLOCK
 public class ClusterStateUpdaters {
     private static final Logger logger = LogManager.getLogger(ClusterStateUpdaters.class);
 
-    static ClusterState setLocalNode(final ClusterState clusterState, DiscoveryNode localNode) {
+    public static ClusterState setLocalNode(final ClusterState clusterState, DiscoveryNode localNode) {
         return ClusterState.builder(clusterState)
             .nodes(DiscoveryNodes.builder().add(localNode).localNodeId(localNode.getId()).build())
             .build();

server/src/main/java/org/elasticsearch/gateway/GatewayMetaState.java

@@ -476,7 +476,7 @@ public class GatewayMetaState implements Closeable {
     /**
      * Encapsulates the incremental writing of metadata to a {@link PersistedClusterStateService.Writer}.
      */
-    static class LucenePersistedState implements PersistedState {
+    public static class LucenePersistedState implements PersistedState {
 
         private long currentTerm;
         private ClusterState lastAcceptedState;
@@ -486,8 +486,11 @@ public class GatewayMetaState implements Closeable {
         private final AtomicReference<PersistedClusterStateService.Writer> persistenceWriter = new AtomicReference<>();
         private boolean writeNextStateFully;
 
-        LucenePersistedState(PersistedClusterStateService persistedClusterStateService, long currentTerm, ClusterState lastAcceptedState)
-            throws IOException {
+        public LucenePersistedState(
+            PersistedClusterStateService persistedClusterStateService,
+            long currentTerm,
+            ClusterState lastAcceptedState
+        ) throws IOException {
             this.persistedClusterStateService = persistedClusterStateService;
             this.currentTerm = currentTerm;
             this.lastAcceptedState = lastAcceptedState;

server/src/main/java/org/elasticsearch/gateway/PersistedClusterStateService.java

@@ -274,8 +274,7 @@ public class PersistedClusterStateService {
         }
     }
 
-    // exposed for tests
-    Directory createDirectory(Path path) throws IOException {
+    protected Directory createDirectory(Path path) throws IOException {
         // it is possible to disable the use of MMapDirectory for indices, and it may be surprising to users that have done so if we still
         // use a MMapDirectory here, which might happen with FSDirectory.open(path), so we force an NIOFSDirectory to be on the safe side.
         return new NIOFSDirectory(path);

server/src/test/java/org/elasticsearch/gateway/GatewayMetaStatePersistedStateTests.java

@@ -537,7 +537,7 @@ public class GatewayMetaStatePersistedStateTests extends ESTestCase {
             () -> 0L
         ) {
             @Override
-            Directory createDirectory(Path path) {
+            protected Directory createDirectory(Path path) {
                 final MockDirectoryWrapper wrapper = newMockFSDirectory(path);
                 wrapper.setAllowRandomFileNotFoundException(randomBoolean());
                 wrapper.setRandomIOExceptionRate(ioExceptionRate.get());

server/src/test/java/org/elasticsearch/gateway/PersistedClusterStateServiceTests.java

@@ -476,7 +476,7 @@ public class PersistedClusterStateServiceTests extends ESTestCase {
                 () -> 0L
             ) {
                 @Override
-                Directory createDirectory(Path path) throws IOException {
+                protected Directory createDirectory(Path path) throws IOException {
                     return new FilterDirectory(super.createDirectory(path)) {
                         @Override
                         public IndexOutput createOutput(String name, IOContext context) throws IOException {
@@ -522,7 +522,7 @@ public class PersistedClusterStateServiceTests extends ESTestCase {
                 () -> 0L
             ) {
                 @Override
-                Directory createDirectory(Path path) throws IOException {
+                protected Directory createDirectory(Path path) throws IOException {
                     return new FilterDirectory(super.createDirectory(path)) {
                         @Override
                         public void sync(Collection<String> names) {
@@ -571,7 +571,7 @@ public class PersistedClusterStateServiceTests extends ESTestCase {
                 () -> 0L
             ) {
                 @Override
-                Directory createDirectory(Path path) throws IOException {
+                protected Directory createDirectory(Path path) throws IOException {
                     return new FilterDirectory(super.createDirectory(path)) {
                         @Override
                         public void rename(String source, String dest) throws IOException {