feat(raft-library): task 3.1 — raft_init validation, state init, raft_snapshot; 12 tests

src/lib/raft/raft.c

@@ -12,8 +12,40 @@ void raft_snapshot(const raft_state_t *s, raft_snapshot_t *snap)
 
 int raft_init(raft_state_t *s, const raft_config_t *cfg)
 {
-    (void)s;
-    (void)cfg;
+    /* Validate required callbacks and n_peers before touching *s */
+    if (cfg->n_peers < 1)
+        return -EINVAL;
+    if (!cfg->cbs)
+        return -EINVAL;
+    if (!cfg->cbs->on_send_vote_request)
+        return -EINVAL;
+    if (!cfg->cbs->on_become_leader)
+        return -EINVAL;
+    if (!cfg->cbs->on_become_follower)
+        return -EINVAL;
+    if (!cfg->cbs->on_persist)
+        return -EINVAL;
+    if (!cfg->cbs->on_schedule_timeout)
+        return -EINVAL;
+    if (!cfg->cbs->on_cancel_timeout)
+        return -EINVAL;
+    if (!cfg->cbs->on_start_election_after_delay)
+        return -EINVAL;
+
+    s->term               = cfg->initial_term;
+    s->role               = RAFT_FOLLOWER;
+    s->voted_for          = cfg->initial_voted_for;
+    s->voted_for_term     = 0;
+    s->n_peers            = cfg->n_peers;
+    s->self_idx           = cfg->self_idx;
+    s->votes_granted      = 0;
+    s->replies_received   = 0;
+    s->election_decided   = 0;
+    s->election_timeout_ms = cfg->election_timeout_ms ? cfg->election_timeout_ms : 2000;
+    s->my_priority        = cfg->my_priority;
+    s->cbs                = cfg->cbs;
+    s->ctx                = cfg->ctx;
+
     return 0;
 }
 

src/lib/raft/raft.h

@@ -12,6 +12,9 @@ typedef enum {
     RAFT_LEADER    = 2,
 } raft_role_t;
 
+/* Forward declaration — full definition follows raft_state_t */
+typedef struct raft_callbacks_t raft_callbacks_t;
+
 /* raft_state_t: pure Raft consensus state for one node.
  *
  * Contains only the Raft invariant state.  Application-specific fields
@@ -29,6 +32,9 @@ typedef struct {
     int          election_decided;   /* 1 once on_become_leader/follower fired */
     uint32_t     election_timeout_ms;
     int          my_priority;        /* priority index for jitter (0 = highest) */
+    /* set by raft_init — needed by the state machine to fire callbacks */
+    const raft_callbacks_t *cbs;
+    void        *ctx;
 } raft_state_t;
 
 /* raft_snapshot_t: point-in-time read of all Raft state for logging/debugging */
@@ -57,7 +63,7 @@ typedef struct {
  *   on_vote_eligible  — if NULL, all Raft-eligible candidates are granted
  *   on_trace          — if NULL, tracing is suppressed
  */
-typedef struct {
+typedef struct raft_callbacks_t {
     /* REQUIRED: Send a RequestVote RPC to peer peer_idx for the given term.
      * The caller encodes config_tag, log_lsn, and any other fields in the wire RPC. */
     int  (*on_send_vote_request)(void *ctx, int peer_idx, uint64_t term);