tower: prevent publish on old roots popped from tower

Author: emwang-jump

src/choreo/ghost/fd_ghost.h

@@ -345,17 +345,19 @@ FD_FN_PURE static inline fd_ghost_ele_t const      * fd_ghost_root_const    ( fd
    NULL if not found. */
 
 FD_FN_PURE static inline fd_ghost_ele_t *
-fd_ghost_query( fd_ghost_t * ghost, fd_hash_t const * hash_id ) {
+fd_ghost_query( fd_ghost_t * ghost, fd_hash_t const * hash ) {
+  if( FD_UNLIKELY( !hash ) ) { return NULL; }
   fd_ghost_hash_map_t * map  = fd_ghost_hash_map( ghost );
   fd_ghost_ele_t      * pool = fd_ghost_pool( ghost );
-  return fd_ghost_hash_map_ele_query( map, hash_id, NULL, pool );
+  return fd_ghost_hash_map_ele_query( map, hash, NULL, pool );
 }
 
 FD_FN_PURE static inline fd_ghost_ele_t const *
-fd_ghost_query_const( fd_ghost_t const * ghost, fd_hash_t const * hash_id ) {
+fd_ghost_query_const( fd_ghost_t const * ghost, fd_hash_t const * hash ) {
+  if( FD_UNLIKELY( !hash ) ) { return NULL; }
   fd_ghost_hash_map_t const * map  = fd_ghost_hash_map_const ( ghost );
   fd_ghost_ele_t      const * pool = fd_ghost_pool_const( ghost );
-  return fd_ghost_hash_map_ele_query_const( map, hash_id, NULL, pool );
+  return fd_ghost_hash_map_ele_query_const( map, hash, NULL, pool );
 }
 
 /* fd_ghost_hash returns the hash_id of the ele keyed by `slot`.

src/discof/tower/fd_tower_tile.c

@@ -307,8 +307,12 @@ after_frag( ctx_t *             ctx,
   ulong root = fd_tower_vote( ctx->tower, vote_slot );
   if( FD_LIKELY( root != FD_SLOT_NULL ) ) {
     fd_hash_t const * root_bid = fd_ghost_hash( ctx->ghost, root );
-    fd_ghost_publish( ctx->ghost, root_bid );
-    fd_stem_publish( stem, ctx->replay_out_idx, root, 0UL, 0UL, 0UL, tsorig, fd_frag_meta_ts_comp( fd_tickcount() ) );
+    if( FD_UNLIKELY( !root_bid ) ) {
+      FD_LOG_WARNING(( "Lowest vote slot %lu is not in ghost, skipping publish", root ));
+    } else {
+      fd_ghost_publish( ctx->ghost, root_bid );
+      fd_stem_publish( stem, ctx->replay_out_idx, root, 0UL, 0UL, 0UL, tsorig, fd_frag_meta_ts_comp( fd_tickcount() ) );
+    }
     ctx->root = root;
   }