Complete HandleAppendEntriesRequest (raft.tla:327) + UpdateTerm (raft.tla:406),
implemented as one function to avoid a misleading partial handler. Fixed step
order: UpdateTerm FIRST on every RPC incl. heartbeat (G5, strictly-greater,
clears voted_for, persists, leader step-down fires on_become_follower) ->
stale reject -> candidate step-down -> logOk (G2) -> reject if !logOk ->
accept (already-have / conflict-truncate-then-repersist (G3) / append).
Never advances commit, never does transport I/O.
Review-applied: logOk now includes the explicit prev_log_index <= log_len bound
(raft.tla:330 / Req 4.1) instead of relying solely on the 0-absent sentinel;
added a candidate-equal-term-logOk-fails step-ordering test. 15 tests, ASAN green.
Leader-only emit (raft.tla AppendEntries:204, Req 3.5 — no-op off leader);
prev_log_index=next_index[j]-1, prev_log_term via on_get_entry_term (0/unqueried
at index 0, Req 3.2-3.3); n_entries=1 when next_index[j]<=log_len else 0 heartbeat
(Req 3.4); leader_commit opaque passthrough. Trace fires only on successful send
(consistency with raft_log_append) and non-leader RAFT_OK asserted — both from
review. 4 spy-based tests. ASAN green.
Leader-only (-EPERM for follower/candidate, no mutation/callback); index=
log_len+1, term=currentTerm (raft.tla ClientRequest:246, Req 2.1-2.4);
persist-before-act: on_persist_entry called once BEFORE log_len advances,
non-zero return propagated with no phantom entry (Req 2.5); no commit-index
advance, no transport I/O. Spy-based tests for all four branches. ASAN green.
next_index[]/match_index[]/pre_vote_replies[] are fixed-size RAFT_MAX_PEERS
arrays indexed by peer; without an upper-bound check a caller passing
n_peers > 8 would OOB-write in the leader-progress and pre-vote loops.
Add the guard (returns -EINVAL, no mutation) + canary-checked test.
Latent since task 1.1; surfaced by task 2.2 review (first loop writes into
the new arrays). No current caller exceeds the bound (sim caps at 8, HA <= 4).
next_index[j]=log_len+1, match_index[j]=0 for every peer at both win paths
(single-node RAFT_ELECTED_IMMEDIATELY in raft_start_election; multi-node
RAFT_BECAME_LEADER in raft_on_vote_reply) via shared raft_init_leader_progress
helper (raft.tla BecomeLeader, Req 3.1). Suite green under ASAN.
2.1: raft_init returns -EINVAL when any of on_persist_entry/on_get_entry_term/
on_send_append_entries/on_truncate_from is NULL (Req 7.1-7.4), before any write
to *s; restores s->log_len = cfg->initial_log_len (Req 1.1).
8.1: raft_sim gains a per-node in-memory log (term+bytes per 1-based index) and
an AE buffer queue; wires all four callbacks (persist/get-term/truncate/send).
Pulled forward to land with 2.1 so the stricter init does not leave the
sim/proto suite red between tasks. AE delivery deferred to 8.2.
Suite green under ASAN (Ok:1 Fail:0).
Four property-style raft tests proving the PreVote API preserves the safety
invariants: term/voted_for/role never change and on_persist never fires across
mixed begin/request/reply sequences (WON and LOST); a WON round creates no leader
(stays FOLLOWER); and the real-vote higher-term-adopt + step-down + quorum-elect
path is unchanged (bug-339/340 intact). Records the TLA+/checklist consistency
argument (RN-1) in test_raft.c and research.md, citing the tests as evidence.
Raft suite 123/0/0; zero production change.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
raft_on_pre_vote_reply: per-peer-deduped tally returning WON at quorum
((n_peers/2)+1), LOST when all non-self peers reply without quorum, else
PENDING; bounds-guards peer_idx. Never fires become-leader/follower, never
mutates term/voted_for/role, never persists. 8 RED-first tests (3- and 5-node,
dedup, out-of-range, purity). Raft PreVote pure core complete.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
raft_begin_pre_vote: compute prospective term (term+1) locally without
persisting, arm the pre_vote_* tally with a self-grant, NULL-safely probe each
non-self peer, return RAFT_PRE_VOTE_WON for single-node else RAFT_OK. Stays
FOLLOWER, schedules no timeout, mutates no persistent state. 6 RED-first tests.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
raft_on_pre_vote_request: deny on stale term, else reuse on_vote_eligible
(primary/heartbeat-stickiness/catch-up gates). Never mutates term/voted_for/
role and never persists or adopts a higher term. 6 RED-first raft unit tests
assert the purity invariant; libxce suite green.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Election protocol fixes validated against raft.tla invariants:
- ha_init_raft(): one-time raft state init at startup (re-init would lose
durable election progress); n_peers = full cluster size including self
- handle_request_vote(): higher-term step-down moved BEFORE the role gate
(split-brain fix); standby vote-deny now requires a live primary control
channel (primary_ctrl_fd >= 0) AND a fresh heartbeat
- ha_heartbeat_is_fresh(): derive freshness from ha->last_activity (the
field production actually writes); the orphaned last_heartbeat timespec
had no production writer, leaving the vote-deny gate inert (bug-337);
field removed from ha_state_t
- handle_request_vote(): restore same-candidate idempotent re-grant —
deny only a DIFFERENT candidate in the same term, matching raft.c and
Raft §5.2 votedFor ∈ {Nil, candidateId} (bug-338)
- raft_init(): restore voted_for_term alongside a persisted vote; leaving
it 0 allowed a double vote in the same term across a restart (bug-339)
- myapp_run(): leader_known check treats a vote recorded under this node's
own name as a self-vote — production persists the real candidate name,
the "self" placeholder only appears in test mode
- raft_on_vote_request(): leader steps down on higher-term vote request
instead of denying it
Tests: test_proto_H6_restored_vote_blocks_second_vote added; H1 restore
assertion strengthened; test_ha_vote_gate.c driven through last_activity +
primary_ctrl_fd (the real production fields). Full /xce-build all green
(lib + controller + scheduler + Go suites, 0 failures, ASAN clean).
deploy-ha.sh: start.sh now forwards extra args to the controller binary.
