Affects Version/s: Minecraft 1.11.2, Minecraft 17w06a, Minecraft 1.13.2, Minecraft 19w08b, Minecraft 19w09a, Minecraft 19w11a, Minecraft 19w11b, 21w05b
Fix Version/s: None
Based on 1.11.2 decompiled using MCP 9.35 rc1
The method net.minecraft.world.WorldEntitySpawner.findChunksForSpawning(WorldServer, boolean, boolean, boolean) which spawns mobs in the world and the method net.minecraft.tileentity.MobSpawnerBaseLogic.updateSpawner() which spawns a mob for a mob spawner call the method net.minecraft.entity.EntityLiving.isNotColliding() before calling the method net.minecraft.entity.EntityLiving.onInitialSpawn(DifficultyInstance, IEntityLivingData), which can make a mob be a baby. This makes it impossible for baby mobs to spawn in smaller spaces.
Note: Fixing this might break existing mob farms.
- Create a Superflat world with the following preset
- Set the time to night
- Use the /say command to list all zombies
→ It won't find any zombies even though baby zombies would have enough space to spawn