databendlabs / openraft / 28227196545

87%

Build Type

push

github

Committed by drmingdrmer

Commit Message

fix: reject stale transfer-leader target election

# Summary

Prevent a transfer target from starting a leadership-transfer election
before it has flushed the leader's expected log state, and return a
non-fatal transfer response when the target is not ready.

# Details

Transfer-leader requests now carry the leader's expected last log id.
The target waits for matching flushed progress and reports
`LogNotFlushed` or `VoteChanged` instead of blindly submitting an
election.

The transfer-leader network and public Raft APIs now return
`TransferLeaderResponse`, so callers can distinguish delivery failures
from transfer rejection. `Candidate::grant_by()` also treats votes from
nodes outside the quorum progress as ignored rather than panicking.

A regression test covers the promoted-learner window from issue #1805,
where the leader already sees a learner as a voter but the target has
not replicated its promotion log yet.

- Fix: #1805

Coverage Stats

88 of 97 new or added lines in 6 files covered. (90.72%)

5 existing lines in 2 files now uncovered.

16925 of 19463 relevant lines covered (86.96%)

160865.54 hits per line