ref: ae73ad76ef95f0e40868436cb750126322051dd0
parent: 84ec2a0a77d63450311f7c25b36d4b9f7e3c53e1
author: Ben Harris <bjh21@bjh21.me.uk>
date: Sat Feb 4 11:50:55 EST 2023
Range: Don't fail an assertion on an all-black board
If there are no white squares, then Range's check that all the white
squares form a connected component goes wrong. Skip the check in that
case to avoid an assretion violation ("edsf_canonify: Assertion `index
>= 0' failed."). This can be demonstrated by starting a game with no
clues (e.g. "range 3:i") and then filling in every square.