[RATIS-1817] Do not send StartLeaderElection when leaderLastEntry is null

• Type: Sub-task
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 3.0.0, 2.5.0
• Component/s: server
• Assignee: Kaijie Chen
• Reporter: Kaijie Chen
• Created: 20/Mar/23 07:49
• Updated: 27/Apr/23 17:33
• Resolved: 20/Mar/23 10:03

Description

We should not send StartLeaderElection to the transferee when leaderLastEntry is null.
Because leaderLastEntry is expected to be non-null in RaftServerImpl#startLeaderElection:

if (leaderLastEntry == null) {
  LOG.warn("{}: receive null leaderLastEntry which is unexpected", getMemberId());
  return ServerProtoUtils.toStartLeaderElectionReplyProto(leaderId, getMemberId(), false);
}

Issue Links

• links to: GitHub Pull Request #857