trade_traderequest() logic causes no err msgs

void trade_traderequest(struct map_session_data *sd, struct map_session_data *target_sd)
{
    int level;

    nullpo_retv(sd);

    if (map[sd->bl.m].flag.notrade) {
        clif_displaymessage (sd->fd, msg_txt(272));
        return; //Can't trade in notrade mapflag maps.
    }

    if (target_sd == NULL || sd == target_sd) {
        clif_tradestart(sd, 1); // character does not exist
        return;
    }

    if (target_sd->npc_id)
    {    //Trade fails if you are using an NPC.
        clif_tradestart(sd, 2);
        return;
    }

    if (!battle_config.invite_request_check) {
        if (target_sd->guild_invite > 0 || target_sd->party_invite > 0 || target_sd->adopt_invite) {
            clif_tradestart(sd, 2);
            return;
        }
    }

    if ((target_sd->trade_partner != 0) || (sd->trade_partner != 0)) {
        clif_tradestart(sd, 2); // person is in another trade
        return;
    }

    level = pc_isGM(sd);
    if ( !pc_can_give_items(level) || !pc_can_give_items(pc_isGM(target_sd)) ) //check if both GMs are allowed to trade
    {
        clif_displaymessage(sd->fd, msg_txt(246));
        clif_tradestart(sd, 2); // GM is not allowed to trade
        return;
    }
    
    //Fixed. Only real GMs can request trade from far away! [Lupus]
    if (level < battle_config.lowest_gm_level && (sd->bl.m != target_sd->bl.m ||
        !check_distance_bl(&sd->bl, &target_sd->bl, TRADE_DISTANCE)
    )) {
        clif_tradestart(sd, 0); // too far
        return;
    }
    
    target_sd->trade_partner = sd->status.account_id;
    sd->trade_partner = target_sd->status.account_id;
    clif_traderequest(target_sd, sd->status.name);
}

void clif_tradestart(struct map_session_data* sd, uint8 type)
{
    int fd = sd->fd;
    
#if PACKETVER < 6
    WFIFOHEAD(fd,packet_len(0xe7));
    WFIFOW(fd,0) = 0xe7;
    WFIFOB(fd,2) = type;
    WFIFOSET(fd,packet_len(0xe7));
#else
    struct map_session_data* tsd = map_id2sd(sd->trade_partner);
    if( !tsd ) return;

    WFIFOHEAD(fd,packet_len(0x1f5));
    WFIFOW(fd,0) = 0x1f5;
    WFIFOB(fd,2) = type;
    WFIFOL(fd,3) = tsd->status.char_id;
    WFIFOW(fd,7) = tsd->status.base_level;
    WFIFOSET(fd,packet_len(0x1f5));
#endif
}