I guess this is a know problem and Aikar is already working on it, but since a quick search of the forums didn't give me any results I'm posting it. If it's a duplicate please ignore it. I was making a tunnel on the nether when the animal update happened, and suddently my tunnel was overrun with pigmen (lots of gold to me), and the sounds of a lot of ghasts outside. I didn't go out for fear of ghasts and continue working on the tunnel. What seemed weird to me was that the ghast suddently started shooting. At first I thought a supporter was ouside, fighting, since my tunnel was completely sealed, and none was visible on the live map. But suddently the floor of my tunnel exploded, with a very long hole made by a ghast that manage to demolish more than 20 layers of netherrack to get at me.
Hmm weird... This would not be a bug with our code (I assure you we have not touched monster AI code yet... And when we do, itll be for animals only) Probally yet another 1.3 glitch... I'm really sad with Mojang atm.
That's been fixed for a few days now.And that only dealt with spawning and density, nothing to do with AI.
Anyone can see both me and the tunnel on the live map, so not really worth it. I started the tunnel about a week ago, and with the fewer ghasts perhaps I didn't notice this untill their numbers rocketed. I noticed that it's just a few spots where they can see me, if I move a block forward or backwards on the tunnel they stop shooting. This one managed to blast thru because I stayed still for a long time. Before creating this tunnel I walked a lot thru nether tunnels, and never had any ghasts fire at me, but I didn't stopped in the middle, so perhaps I just haven't noticed.
Further investigation reveled that about a year ago there was a bug with ghasts, when they spawned in a small area and part of them were inside a wall (but not enough to suffocate them), they could see thru walls. Is it possible that the changes in spawn behavior of ghast makes them more likely to spawn partially inside a block?
No. We did not touch where the game chooses to spawn them.. We simply cancel spawns when we dont want it. MC still decides the location of placement, we just choose whether we like it or not.