test(ha-convergence-recovery): RED quorum transition logging tests + seam (task 5.1)

src/controller/ha_convergence.c

@@ -56,6 +56,13 @@
  * Tests set these before exercising the restart/fatal contract. */
 int  (*ha_restart_hook)(cluster_t *c)   = NULL;
 void (*ha_fatal_hook)(const char *msg)  = NULL;
+
+/* Quorum-transition emission-count seam (task 5.x, Req 8.1-8.3) — defined here,
+ * declared in ha.h.  ha_log_quorum_transition invokes this once per WARN it
+ * emits so the counter-hook tests can assert once-per-transition + counts.
+ * NULL until a test installs it. */
+void (*ha_quorum_transition_log_hook)(int lost, int connected,
+                                      int required) = NULL;
 #endif
 
 /*
@@ -375,6 +382,24 @@ void cluster_apply_ctrlhello_reply(cluster_t *c, uint64_t committed_lsn,
     (void)ha_rejoin_reconcile(c, committed_lsn);
 }
 
+/*
+ * ha_log_quorum_transition — RED scaffold (ha-convergence-recovery task 5.1).
+ *
+ * Task 5.2 replaces this body with the real edge detector: evaluate the current
+ * write-quorum state (ha_has_write_quorum, ha.c), compare against ha->quorum_lost,
+ * and on a transition CAS-flip the flag and emit exactly one WARN with the
+ * connected/required counts (Req 8.1, 8.2), invoking ha_quorum_transition_log_hook
+ * once under XCE_TESTING.  Repeated calls with no state change emit nothing
+ * (Req 8.3); a later loss/restore cycle logs again (edge detector, not a latch).
+ *
+ * This RED stub does NOTHING: no edge detection, no flag flip, no WARN, no hook
+ * invocation — so the task 5.1 quorum-transition tests FAIL until 5.2 lands.
+ */
+void ha_log_quorum_transition(ha_state_t *ha)
+{
+    (void)ha; /* RED scaffold — task 5.2 implements the edge detection. */
+}
+
 #ifdef XCE_TESTING
 /* ───────────────────────────────────────────────────────────────────────────
  * ha_walack_continuation_for_test — task 4.2 GREEN.