GitLab

new_route_len() ends with

  if (num_acceptable_routers < 2) {
    log_info(LD_CIRC,
             "Not enough acceptable routers (%d). Discarding this circuit.",
             num_acceptable_routers);
    return -1;
  }

  if (num_acceptable_routers < routelen) {
    log_info(LD_CIRC,"Not enough routers: cutting routelen from %d to %d.",
             routelen, num_acceptable_routers);
    routelen = num_acceptable_routers;
  }

We should replace this with the simpler

  if (num_acceptable_routers < 3) {
    log_info(LD_CIRC,
             "Not enough acceptable routers (%d). Discarding this circuit.",
             num_acceptable_routers);
    return -1;
  } 

to simplify things.

Note that the "oh hey let's just use two hops" case doesn't trigger in a real Tor network, because we won't be willing to make circuits if we don't have at least x% of the descriptors, so this code only comes into play when the consensus says there are 5 or something relays total.