Fast refresh indices to use search shards (elastic#117111)

Backport of PR elastic#116658.

Changes of this PR are ineffective for stateful, and backport is not
used in serverless. This is mostly to adopt the new transport version
in stateful to keep them consecutive.

Relates ES-9573

Author: kingherc

server/src/main/java/org/elasticsearch/TransportVersions.java

@@ -201,6 +201,7 @@ static TransportVersion def(int id) {
     public static final TransportVersion QUERY_RULES_LIST_INCLUDES_TYPES = def(8_792_00_0);
     public static final TransportVersion INDEX_STATS_ADDITIONAL_FIELDS = def(8_793_00_0);
     public static final TransportVersion INDEX_STATS_ADDITIONAL_FIELDS_REVERT = def(8_794_00_0);
+    public static final TransportVersion FAST_REFRESH_RCO_2 = def(8_795_00_0);
 
     /*
      * STOP! READ THIS FIRST! No, really,

server/src/main/java/org/elasticsearch/action/admin/indices/refresh/TransportUnpromotableShardRefreshAction.java

@@ -24,7 +24,7 @@
 
 import java.util.List;
 
-import static org.elasticsearch.TransportVersions.FAST_REFRESH_RCO;
+import static org.elasticsearch.TransportVersions.FAST_REFRESH_RCO_2;
 import static org.elasticsearch.index.IndexSettings.INDEX_FAST_REFRESH_SETTING;
 
 public class TransportUnpromotableShardRefreshAction extends TransportBroadcastUnpromotableAction<
@@ -76,17 +76,17 @@ protected void unpromotableShardOperation(
             return;
         }
 
-        // During an upgrade to FAST_REFRESH_RCO, we expect search shards to be first upgraded before the primary is upgraded. Thus,
+        // During an upgrade to FAST_REFRESH_RCO_2, we expect search shards to be first upgraded before the primary is upgraded. Thus,
         // when the primary is upgraded, and starts to deliver unpromotable refreshes, we expect the search shards to be upgraded already.
         // Note that the fast refresh setting is final.
         // TODO: remove assertion (ES-9563)
         assert INDEX_FAST_REFRESH_SETTING.get(shard.indexSettings().getSettings()) == false
-            || transportService.getLocalNodeConnection().getTransportVersion().onOrAfter(FAST_REFRESH_RCO)
+            || transportService.getLocalNodeConnection().getTransportVersion().onOrAfter(FAST_REFRESH_RCO_2)
             : "attempted to refresh a fast refresh search shard "
                 + shard
                 + " on transport version "
                 + transportService.getLocalNodeConnection().getTransportVersion()
-                + " (before FAST_REFRESH_RCO)";
+                + " (before FAST_REFRESH_RCO_2)";
 
         ActionListener.run(responseListener, listener -> {
             shard.waitForPrimaryTermAndGeneration(

server/src/main/java/org/elasticsearch/cluster/routing/OperationRouting.java

@@ -32,7 +32,7 @@
 import java.util.Set;
 import java.util.stream.Collectors;
 
-import static org.elasticsearch.TransportVersions.FAST_REFRESH_RCO;
+import static org.elasticsearch.TransportVersions.FAST_REFRESH_RCO_2;
 import static org.elasticsearch.index.IndexSettings.INDEX_FAST_REFRESH_SETTING;
 
 public class OperationRouting {
@@ -309,7 +309,7 @@ public static boolean canSearchShard(ShardRouting shardRouting, ClusterState clu
         // TODO: remove if and always return isSearchable (ES-9563)
         if (INDEX_FAST_REFRESH_SETTING.get(clusterState.metadata().index(shardRouting.index()).getSettings())) {
             // Until all the cluster is upgraded, we send searches/gets to the primary (even if it has been upgraded) to execute locally.
-            if (clusterState.getMinTransportVersion().onOrAfter(FAST_REFRESH_RCO)) {
+            if (clusterState.getMinTransportVersion().onOrAfter(FAST_REFRESH_RCO_2)) {
                 return shardRouting.isSearchable();
             } else {
                 return shardRouting.isPromotableToPrimary();

server/src/test/java/org/elasticsearch/cluster/routing/IndexRoutingTableTests.java

@@ -20,7 +20,7 @@
 
 import java.util.List;
 
-import static org.elasticsearch.TransportVersions.FAST_REFRESH_RCO;
+import static org.elasticsearch.TransportVersions.FAST_REFRESH_RCO_2;
 import static org.elasticsearch.index.IndexSettings.INDEX_FAST_REFRESH_SETTING;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.mock;
@@ -43,7 +43,7 @@ private void innerReadyForSearch(boolean fastRefresh, boolean beforeFastRefreshR
             Settings.builder().put(INDEX_FAST_REFRESH_SETTING.getKey(), fastRefresh).build()
         );
         when(clusterState.getMinTransportVersion()).thenReturn(
-            beforeFastRefreshRCO ? TransportVersion.fromId(FAST_REFRESH_RCO.id() - 1_00_0) : TransportVersion.current()
+            beforeFastRefreshRCO ? TransportVersion.fromId(FAST_REFRESH_RCO_2.id() - 1_00_0) : TransportVersion.current()
         );
         // 2 primaries that are search and index
         ShardId p1 = new ShardId(index, 0);