Check allocation id when failing shard on recovery (#50656)

A failure of a recovering shard can race with a new allocation of the shard, and cause the new
allocation to be failed as well. This can result in a shard being marked as initializing in the cluster
state, but not exist on the node anymore.

Closes #50508

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

@@ -699,7 +699,8 @@ public class IndicesClusterStateService extends AbstractLifecycleComponent imple
         }
     }
 
-    private synchronized void handleRecoveryFailure(ShardRouting shardRouting, boolean sendShardFailure, Exception failure) {
+    // package-private for testing
+    synchronized void handleRecoveryFailure(ShardRouting shardRouting, boolean sendShardFailure, Exception failure) {
         failAndRemoveShard(shardRouting, sendShardFailure, "failed recovery", failure, clusterService.state());
     }
 
@@ -708,7 +709,10 @@ public class IndicesClusterStateService extends AbstractLifecycleComponent imple
         try {
             AllocatedIndex<? extends Shard> indexService = indicesService.indexService(shardRouting.shardId().getIndex());
             if (indexService != null) {
-                indexService.removeShard(shardRouting.shardId().id(), message);
+                Shard shard = indexService.getShardOrNull(shardRouting.shardId().id());
+                if (shard != null && shard.routingEntry().isSameAllocation(shardRouting)) {
+                    indexService.removeShard(shardRouting.shardId().id(), message);
+                }
             }
         } catch (ShardNotFoundException e) {
             // the node got closed on us, ignore it

server/src/test/java/org/elasticsearch/indices/cluster/IndicesClusterStateServiceRandomUpdatesTests.java

@@ -255,6 +255,40 @@ public class IndicesClusterStateServiceRandomUpdatesTests extends AbstractIndice
 
     }
 
+    public void testRecoveryFailures() {
+        disableRandomFailures();
+        String index = "index_" + randomAlphaOfLength(8).toLowerCase(Locale.ROOT);
+        ClusterState state = ClusterStateCreationUtils.state(index, randomBoolean(),
+            ShardRoutingState.STARTED, ShardRoutingState.INITIALIZING);
+
+        // the initial state which is derived from the newly created cluster state but doesn't contain the index
+        ClusterState previousState = ClusterState.builder(state)
+            .metaData(MetaData.builder(state.metaData()).remove(index))
+            .routingTable(RoutingTable.builder().build())
+            .build();
+
+        // pick a data node to simulate the adding an index cluster state change event on, that has shards assigned to it
+        final ShardRouting shardRouting = state.routingTable().index(index).shard(0).replicaShards().get(0);
+        final ShardId shardId = shardRouting.shardId();
+        DiscoveryNode node = state.nodes().get(shardRouting.currentNodeId());
+
+        // simulate the cluster state change on the node
+        ClusterState localState = adaptClusterStateToLocalNode(state, node);
+        ClusterState previousLocalState = adaptClusterStateToLocalNode(previousState, node);
+        IndicesClusterStateService indicesCSSvc = createIndicesClusterStateService(node, RecordingIndicesService::new);
+        indicesCSSvc.start();
+        indicesCSSvc.applyClusterState(new ClusterChangedEvent("cluster state change that adds the index", localState, previousLocalState));
+
+        assertNotNull(indicesCSSvc.indicesService.getShardOrNull(shardId));
+
+        // check that failing unrelated allocation does not remove shard
+        indicesCSSvc.handleRecoveryFailure(shardRouting.reinitializeReplicaShard(), false, new Exception("dummy"));
+        assertNotNull(indicesCSSvc.indicesService.getShardOrNull(shardId));
+
+        indicesCSSvc.handleRecoveryFailure(shardRouting, false, new Exception("dummy"));
+        assertNull(indicesCSSvc.indicesService.getShardOrNull(shardId));
+    }
+
     public ClusterState randomInitialClusterState(Map<DiscoveryNode, IndicesClusterStateService> clusterStateServiceMap,
                                                   Supplier<MockIndicesService> indicesServiceSupplier) {
         List<DiscoveryNode> allNodes = new ArrayList<>();