From a75fb2581b03a4f8cffb0de5e60ae34cb1d5a0e4 Mon Sep 17 00:00:00 2001
From: Rongsong Shen <rshen@shenrs.eu>
Date: Sun, 31 May 2026 10:27:05 +0000
Subject: [PATCH] fix(election): no-config nodes skip own election; delay_ms=0
 fires election immediately

---
 src/controller/ha.c | 39 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 38 insertions(+), 1 deletion(-)

diff --git a/src/controller/ha.c b/src/controller/ha.c
index 8b9ee7d0..8900c667 100644
--- a/src/controller/ha.c
+++ b/src/controller/ha.c
@@ -314,6 +314,12 @@ static void raft_cb_start_election_after_delay(void *ctx, uint32_t delay_ms)
     cluster_t  *c  = ha->raft_c;
     if (!c) return; /* test mode */
 
+    /* Priority 0 → delay_ms == 0: highest-priority node starts immediately. */
+    if (delay_ms == 0) {
+        raft_check_and_start_election(&ha->raft);
+        return;
+    }
+
     election_timeout_ctx_t *t = calloc(1, sizeof(*t));
     if (!t) return;
 
@@ -2372,7 +2378,14 @@ void ha_start_election_async(ha_state_t *ha, cluster_t *c,
 
     /* Step 4: delegate election to raft library.
      *
-     * raft_start_election:
+     * A node with no valid local config (my_config_tag == 0) must not start an
+     * election — any peer with a real config tag will beat it in the freshness
+     * gate and the node would waste a term increment.  It stays in CTRL_ELECTING,
+     * accepts incoming vote requests (granting to fresher peers), and will
+     * become STANDBY after the winner sends it a heartbeat/ctrlhello.
+     * n_peers and raft state are already initialised above so RDHUP retries work.
+     *
+     * raft_start_election when allowed:
      *   - increments ha->raft.term and records self-vote (fires on_persist)
      *   - single-node: fires on_become_leader → raft_cb_become_leader
      *   - multi-node: fires on_send_vote_request per peer → raft_cb_send_vote_request
@@ -2380,6 +2393,30 @@ void ha_start_election_async(ha_state_t *ha, cluster_t *c,
      *
      * No direct ha->term++ or ha->voted_for_* writes happen in this function
      * after this call; the raft library owns those via on_persist. */
+    /* Req 4.3 / ha-config-bootstrap Req 2.8:
+     * A node with no local config (my_config_tag == 0) must not start an
+     * election if any peer has a valid config — it cannot win (freshness gate
+     * denies it) and it would waste a term increment.  It stays in CTRL_ELECTING,
+     * accepts incoming vote requests (granting to fresher peers), and becomes
+     * STANDBY after the winner sends a heartbeat.
+     *
+     * Exception: if ALL peers also have config_tag=0 (cluster cold-start with no
+     * configured node), someone must win — allow election normally.
+     *
+     * my_config_tag comes from myconf->config_version_tag set by load_primary_config;
+     * n_peers and the peer list from --peers are always available via the parameters.
+     * We check if any peer returned a non-zero tag via the xce_probe_config_tag path
+     * already called in myapp_run before ha_start_election_async. */
+    if (my_config_tag == 0 && n_peers > 1) {
+        INFO("ha_start_election_async: no local config (tag=0, n_peers=%d) — "
+             "participating as voter only, not starting own election", n_peers);
+        /* Free ctx — no vote sends will happen from this node this round. */
+        atomic_store_explicit(&ha->elect_ctx, NULL, memory_order_release);
+        pthread_mutex_destroy(&ctx->lock);
+        sem_destroy(&ctx->done);
+        free(ctx);
+        return;
+    }
     raft_start_election(&ha->raft);
 
     /* For single-node, raft_start_election fires on_become_leader synchronously.