Starcraft AI blog

Here’s a little story for anyone who doubts the importance of fixing bugs: Randomhammer’s last 4 games were all decided by bugs.

4. Versus IceBot, Randomhammer rolled terran and went vultures. The vulture attack almost broke through IceBot’s wall, but IceBot got its bunker up and managed to keep 1 marine alive long enough to get in. Randomhammer’s hard-coded switch to tanks was late and its tactics were weak, and IceBot was soon winning. The hostile tank push started, then—IceBot crashed, game to Randomhammer.

3. Oleg Ostroumov crashed at 5 SCVs, before the game was properly underway.

2. Hardcoded crashed on start.

1. Versus zerg ZurZurZur there was at least a game. Randomhammer again rolled terran and this time went for a vulture drop. ZurZurZur sent 4 hydralisks across for a poke, where they met Randomhammer’s small force of marines and vultures, whose purpose is to keep the enemy occupied out front while the drop happens in back. It worked; ZurZurZur’s forces were far out of position, and the vultures killed all but 1 drone before being cleaned up. Then Randomhammer fell into a production freeze and did not produce another unit for the rest of the game, allowing ZurZurZur to slowly recover with its 1 drone and win.

There is a sub-theme here: Crash bugs are the worst. You crash, you lose. Randomhammer could have defeated ZurZurZur on points if it had better vulture micro, even with the production freeze. (It couldn’t have won outright, though, because there were sunkens that existing forces could not have brought down.)

Steamhammer has no known crashing bugs. I went on campaign and exterminated them. Its last crashes due to fixable bugs were in April, and its last recorded crashes on SSCAIT were in May and appear to have been due to bugs in the infrastructure, not in Steamhammer. Some of the bugs I fixed are obscure and their triggers have never occurred in real games. For example, Steamhammer has never had a unit mind controlled, as far as I have seen. The normal unit validity check done on every frame should catch mind controlled squad units and workers before Steamhammer tries to send them orders—though it hasn’t been tested, so I don’t promise it’s correct. But I noticed a loophole: The scouting worker is not in a squad and is not treated like a regular worker. It is controlled directly by ScoutManager, which does not run the validity check. I left a comment in the code where I fixed it. How many years would it have been, do you suppose, before somebody mind controlled the scouting worker and brought about a crash?