Minor cleanup in IndicesClusterStateService (#94623)

Removes some unnecessary parameters from internal methods. Extracted
from #94545 to reduce noise.

Author: DaveCTurner

server/src/main/java/org/elasticsearch/indices/cluster/IndicesClusterStateService.java

@@ -427,14 +427,11 @@ private void removeIndicesAndShards(final ClusterChangedEvent event) {
      * @param state new cluster state
      */
     private void createIndicesAndUpdateShards(final ClusterState state) {
-        DiscoveryNodes nodes = state.nodes();
-        RoutingNode localRoutingNode = state.getRoutingNodes().node(nodes.getLocalNodeId());
+        RoutingNode localRoutingNode = state.getRoutingNodes().node(state.nodes().getLocalNodeId());
         if (localRoutingNode == null) {
             return;
         }
 
-        RoutingTable routingTable = state.routingTable();
-
         // create map of indices to create with shards to fail if index creation fails or create or update shards if an existing index
         // service is found
         final Map<Index, List<ShardRouting>> indicesToCreate = new HashMap<>();
@@ -455,7 +452,7 @@ private void createIndicesAndUpdateShards(final ClusterState state) {
                     if (indexService == null) {
                         indicesToCreate.computeIfAbsent(index, k -> new ArrayList<>()).add(shardRouting);
                     } else {
-                        createOrUpdateShard(state, nodes, routingTable, shardRouting, indexService);
+                        createOrUpdateShard(state, shardRouting, indexService);
                     }
                 }
             }
@@ -485,24 +482,18 @@ private void createIndicesAndUpdateShards(final ClusterState state) {
             }
             // we succeeded in creating the index service, so now we can create the missing shards assigned to this node
             for (ShardRouting shardRouting : entry.getValue()) {
-                createOrUpdateShard(state, nodes, routingTable, shardRouting, indexService);
+                createOrUpdateShard(state, shardRouting, indexService);
             }
         }
     }
 
-    private void createOrUpdateShard(
-        ClusterState state,
-        DiscoveryNodes nodes,
-        RoutingTable routingTable,
-        ShardRouting shardRouting,
-        AllocatedIndex<? extends Shard> indexService
-    ) {
+    private void createOrUpdateShard(ClusterState state, ShardRouting shardRouting, AllocatedIndex<? extends Shard> indexService) {
         Shard shard = indexService.getShardOrNull(shardRouting.shardId().id());
         if (shard == null) {
             assert shardRouting.initializing() : shardRouting + " should have been removed by failMissingShards";
-            createShard(nodes, routingTable, shardRouting, state);
+            createShard(shardRouting, state);
         } else {
-            updateShard(nodes, shardRouting, shard, routingTable, state);
+            updateShard(shardRouting, shard, state);
         }
     }
 
@@ -546,19 +537,21 @@ private void updateIndices(ClusterChangedEvent event) {
         }
     }
 
-    private void createShard(DiscoveryNodes nodes, RoutingTable routingTable, ShardRouting shardRouting, ClusterState state) {
+    private void createShard(ShardRouting shardRouting, ClusterState state) {
         assert shardRouting.initializing() : "only allow shard creation for initializing shard but was " + shardRouting;
 
-        DiscoveryNode sourceNode = null;
-        if (shardRouting.recoverySource().getType() == Type.PEER) {
-            sourceNode = findSourceNodeForPeerRecovery(routingTable, nodes, shardRouting);
-            if (sourceNode == null) {
-                logger.trace("ignoring initializing shard {} - no source node can be found.", shardRouting.shardId());
-                return;
+        try {
+            final DiscoveryNode sourceNode;
+            if (shardRouting.recoverySource().getType() == Type.PEER) {
+                sourceNode = findSourceNodeForPeerRecovery(state.routingTable(), state.nodes(), shardRouting);
+                if (sourceNode == null) {
+                    logger.trace("ignoring initializing shard {} - no source node can be found.", shardRouting.shardId());
+                    return;
+                }
+            } else {
+                sourceNode = null;
             }
-        }
 
-        try {
             final long primaryTerm = state.metadata().index(shardRouting.index()).primaryTerm(shardRouting.id());
             logger.debug("{} creating shard with primary term [{}]", shardRouting.shardId(), primaryTerm);
             indicesService.createShard(
@@ -569,21 +562,15 @@ private void createShard(DiscoveryNodes nodes, RoutingTable routingTable, ShardR
                 failedShardHandler,
                 this::updateGlobalCheckpointForShard,
                 retentionLeaseSyncer,
-                nodes.getLocalNode(),
+                state.nodes().getLocalNode(),
                 sourceNode
             );
         } catch (Exception e) {
             failAndRemoveShard(shardRouting, true, "failed to create shard", e, state);
         }
     }
 
-    private void updateShard(
-        DiscoveryNodes nodes,
-        ShardRouting shardRouting,
-        Shard shard,
-        RoutingTable routingTable,
-        ClusterState clusterState
-    ) {
+    private void updateShard(ShardRouting shardRouting, Shard shard, ClusterState clusterState) {
         final ShardRouting currentRoutingEntry = shard.routingEntry();
         assert currentRoutingEntry.isSameAllocation(shardRouting)
             : "local shard has a different allocation id but wasn't cleaned by removeShards. "
@@ -597,7 +584,7 @@ private void updateShard(
             final IndexMetadata indexMetadata = clusterState.metadata().index(shard.shardId().getIndex());
             primaryTerm = indexMetadata.primaryTerm(shard.shardId().id());
             final Set<String> inSyncIds = indexMetadata.inSyncAllocationIds(shard.shardId().id());
-            final IndexShardRoutingTable indexShardRoutingTable = routingTable.shardRoutingTable(shardRouting.shardId());
+            final IndexShardRoutingTable indexShardRoutingTable = clusterState.routingTable().shardRoutingTable(shardRouting.shardId());
             shard.updateShardState(
                 shardRouting,
                 primaryTerm,
@@ -621,15 +608,15 @@ private void updateShard(
                     "{} master marked shard as initializing, but shard has state [{}], resending shard started to {}",
                     shardRouting.shardId(),
                     state,
-                    nodes.getMasterNode()
+                    clusterState.nodes().getMasterNode()
                 );
             }
-            if (nodes.getMasterNode() != null) {
+            if (clusterState.nodes().getMasterNode() != null) {
                 shardStateAction.shardStarted(
                     shardRouting,
                     primaryTerm,
                     "master "
-                        + nodes.getMasterNode()
+                        + clusterState.nodes().getMasterNode()
                         + " marked shard as initializing, but shard state is ["
                         + state
                         + "], mark shard as started",