WIP

Author: Tim-Brooks

server/src/main/java/org/elasticsearch/cluster/action/shard/ShardStateAction.java

@@ -719,7 +719,9 @@ public ClusterState execute(BatchExecutionContext<StartedShardUpdateTask> batchE
                             tasksToBeApplied.add(taskContext);
                         } else if (invalidShardSplit(startedShardEntry, projectId, initialState)) {
                             logger.debug("{} failing shard started task because split validation failed", startedShardEntry.shardId);
-                            // TODO: Determine correct behavior
+                            // TODO: Currently invalid shard split triggers if the primary term changes, the source primary term changes or
+                            // is >= the target primary term or if the source is relocating. In the second and third scenario this will be
+                            // swallow currently. In the split process we will need to handle this.
                             taskContext.success(task::onSuccess);
                         } else {
                             logger.debug(

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

@@ -1035,7 +1035,15 @@ public void onRecoveryDone(
                     timestampMillisFieldRange,
                     eventIngestedMillisFieldRange,
                     sourcePrimaryTerm,
-                    ActionListener.noop()
+                    new ActionListener<>() {
+                        @Override
+                        public void onResponse(Void unused) {}
+
+                        @Override
+                        public void onFailure(Exception e) {
+                            onRecoveryFailure(new RecoveryFailedException(state, "failed to start after split", e), true);
+                        }
+                    }
                 );
             } else {
                 shardStateAction.shardStarted(