Affects Version/s: 1.15.2, 20w15a
Fix Version/s: 20w22a
The direct impact damage from Wither skulls is not reduced by the Projectile Protection enchantment, unlike damage from Ghast/Blaze fireballs. This may be intentional, but it's inconsistent with ghast fireballs at least.
This is most easily reproduced in a world with no nearby mobs and mob spawning disabled.
- Give yourself two leather helmets, leggings and boots; enchant one set with Projectile Protection IV and leave the other unenchanted
- Set a repeating command block that clears the Wither effect from the player
- Set /gamerule naturalRegeneration false and change to Hard difficulty and Survival mode
- Summon a wither with the following command:
- The wither still attacks, but will stay in place and not chase you, making it easier to get away from it.
- Approach the wither and get hit by one of its skulls while wearing the unenchanted armor, heal yourself to full health and repeat the same with the enchanted armor.
- Spawn a ghast and repeat the same.
Notice how the Projectile Protection armor significantly reduces damage from the ghast, but not the wither.
This is likely because in net.minecraft.world.entity.projectile.WitherSkull.onHitEntity(), the damage source passed to the target entity doesn't call setProjectile() (like ghast/blaze fireballs and arrows do).