spurious "Network is unreachable" error after setting DisableNetwork=1
If DisableNetwork is set to 1 via SETCONF during bootstrapping, Tor sometimes generates spurious errors such as "Network is unreachable". Kathy and I saw this while testing a fix for #11879 (moved). We realize this may be difficult to fix due to the internal architecture / concurrency inside Tor.
See #15713 (moved) for steps to reproduce (but note that an error does not occur every time). In the log that is attached to #15713 (moved) you can see an example: Apr 17 10:28:10.000 [warn] Problem bootstrapping. Stuck at 25%: Loading networkstatus consensus. (Network is unreachable; NOROUTE; count 1; recommendation warn; host 847B1F850344D7876491A54892F904934E4EB85D at 18.104.22.168:443) (the error happens right away if it happens at all – no delay).
This problem may cause some Tor Browser users to be a little confused; all they need to do is click "Open Settings" while Tor Browser was starting up and they will sometimes see an error alert.