replay: fix behaviour when we fail to fetch vote state from funk

Author: topointon-jump

src/discof/replay/fd_replay_tile.c

@@ -585,6 +585,19 @@ fd_replay_out_vote_tower_from_funk(
       return -1;
     }
 
+    /* If the vote account has no lamports, no data, or the first 2 bytes are zeros,
+       then it is not a valid vote account and should be skipped. */
+    if( FD_UNLIKELY( fd_accdb_ref_lamports( peek->acc ) == 0 ) ) {
+      FD_LOG_DEBUG(( "vote account %s has no lamports", FD_BASE58_ENC_32_ALLOCA( pubkey->uc ) ));
+      return -1;
+    }
+    /* Sanity check that the vote account data has been initialized, and the
+       discriminator is none-zero. */
+    if( FD_UNLIKELY( data_sz == 0UL || memcmp( vote_tower_out->acc, "\0\0", 2 ) == 0 ) ) {
+      FD_LOG_DEBUG(( "vote account %s has invalid data", FD_BASE58_ENC_32_ALLOCA( pubkey->uc ) ));
+      return -1;
+    }
+
     fd_memcpy( vote_tower_out->acc, fd_accdb_ref_data_const( peek->acc ), data_sz );
     vote_tower_out->acc_sz = data_sz;
 
@@ -617,12 +630,12 @@ buffer_vote_towers( fd_replay_tile_t *        ctx,
     if( FD_UNLIKELY( vote_state->stake == 0 ) ) continue; /* skip unstaked vote accounts */
     fd_pubkey_t const * vote_account_pubkey = &vote_state->vote_account;
     if( FD_UNLIKELY( ctx->vote_tower_out_len >= (FD_REPLAY_TOWER_VOTE_ACC_MAX-1UL) ) ) FD_LOG_ERR(( "vote_tower_out_len too large" ));
-    if( FD_UNLIKELY( fd_replay_out_vote_tower_from_funk( ctx->accdb,
-                                                         xid,
-                                                         vote_account_pubkey,
-                                                         vote_state->stake,
-                                                         &ctx->vote_tower_out[ctx->vote_tower_out_len++] ) ) ) {
+    fd_replay_tower_t * vote_tower_out = &ctx->vote_tower_out[ ctx->vote_tower_out_len ];
+    int err = fd_replay_out_vote_tower_from_funk( ctx->accdb, xid, vote_account_pubkey, vote_state->stake, vote_tower_out );
+    if( FD_UNLIKELY( err ) ) {
       FD_LOG_DEBUG(( "failed to get vote state for vote account %s", FD_BASE58_ENC_32_ALLOCA( vote_account_pubkey->uc ) ));
+    } else {
+      ctx->vote_tower_out_len++;
     }
   }
   fd_bank_vote_states_prev_end_locking_query( bank );