v0.9.19

Summary:

• Improved:
  • 9bfd517f tolerate leader state reversion upon restart.

Detail:

Improved:

• Improved: 9bfd517f tolerate leader state reversion upon restart; by Zhang Yanpo; 2025-06-10

  When a leader restarted and its log reverted, and tried to re-elect
  itself as leader:

  And when vote request is rejected and see a greater vote,
  it should only update to the non-committed version of the responded vote
  to its local state:

  This prevents a dangerous scenario when state reversion is allowed:

  1. A node was a leader but its state reverted to a previous version;
  2. The node restarts and begins election;
  3. It receives a vote response containing its own previous leader vote;
  4. Without this protection, it would update to that committed vote and
     become leader again;
  5. However, it lacks the necessary logs, causing committed entries to be
     lost or inconsistent;

  By using the non-committed version, we prevent this reverted node from
  becoming leader while still allowing proper vote updates for legitimate
  cases.