The bug
Mobs can attack you through blocks and corners due to miscalculation of attack radius.
How to reproduce
Build a completely sealed off house with no windows or doors from opaque blocks like planks or cobblestone or the like, leave some blocks in the inventory for you to place in step 7.
Make a two-block tall one-block wide empty doorway in the wall for you to go through and to seal off with blocks in step 7.
Outside the house, spawn a Ravager.
Switch to survival mode.
The Ravager should start going for you.
Run in the house, let it hit you once through the empty doorway.
Seal off the doorway with two blocks.
Result: The Ravager is still able to hit the player, from about two blocks away, with a complete wall every possible place in between.
Expected: The Ravager can't attack the player any more.
Example
An example can be seen in this comment.
Old example
I just created a villager in MCEdit with the Create Shops filter to have a custom shop. I saved it and launched MC. The villager started to run around normally in his house but then he went to the door where a zombie was knocking at (wooden door on normal difficulty) and the villager blinked red and got damage and after a few hits he died. The zombie killed him through a closed door and the villager did not run away he always came back to the door until he died.
Additional informations
From @unknown:
There are a number of bug reports about attack radius that are all very similar. MC-2310, MC-18326, MC-50668, MC-63965, MC-71834, and MC-74907 are all about the attack radius of mobs extending through blocks. (Some mobs are more bugged than others, but it’s the same basic problem).
There are also a few related issues:
Code analysis
Based on 1.11.2 decompiled using MCP 9.35 rc1
The problem seems to be the method net.minecraft.entity.ai.EntityAIAttackMelee.checkAndPerformAttack(EntityLivingBase, double) and methods overriding it. They all only test if the mob to attack is in a certain radius to the attacker without testing if blocks are between them.
Possible solutions
Bounding box check
The current behavior would be replaced by only allowing mobs to attack other mobs when their bounding boxes intersect.
Ray casting
The current behavior would be extended to require a ray cast from the attacker to the mob to attack (excluding liquids and blocks without collision box) to return no colliding blocks. Possible use y + height / 1.5 as attack height or have a method for mobs to define their attack height(s?). The height at which the mob to attack will be attacked could for example be y + height / 2 or with multiple tries depending on the height of the mob, for example
for (int attackFraction = 0; attackFraction < height / 2; attackFraction++) {
double attackHeight = y + height * ((attackFraction + 1.0) / (height / 2.0 + 1.0))
}Linked issues
is duplicated by 124
relates to 7
MC-108937
Attack ranges for certain mobs are incorrect
Resolved
MC-116644
Filled water or powder snow cauldron extinguishes burning arrows that hit either side of the cauldron
Open
MCPE-162607
Polar bear attacks passing through blocks
Open
MC-3059
Projectiles can pass through thin surfaces
Reopened
MC-1297
You can attack and be attacked through glass panes
Resolved
Attachments
Comments 100
This is a really annoying problem which I hope is fixed soon. Confirmed to still be an issue on Mineraft 1.6.2 with Java 7 update 25 64-bit.
Maybe this issue should be re-opened. I ran some tests in a creative world and it appears that villagers seem to crowd,mostly around the door, in one or several houses at night.
Because the zombies group before the door and then start hitting the villagers through the door somehow, if one villager turns into a zombie, your whole villager population is killed in one sweep.
That's tracked in MC-264915.
[Mod] markderickson
gnembon
I know I'm not a mod but I think I know the problem. Zombies can't hit mobs but can break doors when they are closed. If the door is open, the zombie can hit mobs but can't break it down. If you place the door sideways, then put it in the open position, zombies can hit mobs (like the villager) through doors. Th other problem might be that Createshops filter was messing it up. If the zombie is making the banging noises than Createshops is the problem. If not it could be either one. I may also be completely wrong.