Expected behavior
Reducing the damage in EntityDamageByEntityEvent has no side effects and just reduces the damage.
Observed/Actual behavior
If the damage is reduced in EntityDamageByEntityEvent, the invulnerability timer for an entity is bypassed for subsequent attacks, due to a mismatch in how Paper calculates the most recent attack damage (lastHurt)
Steps/models to reproduce
Add a listener to EntityDamageByEntityEvent to multiply the damage by 0.9.
Place a breakpoint at LivingEntity.java#1470 (at return false):
if (amount <= this.lastHurt) {
return false;
}If you spam click an entity, verify that this the breakpoint at 1470 is never hit with the listener, but is hit without.
Plugin and Datapack List
N/A
Paper version
This server is running Paper version 1.21.1-119-master@7cd4f2c (2024-10-03T15:19:34Z) (Implementing API version 1.21.1-R0.1-SNAPSHOT)
You are running the latest version
Previous version: 1.21.1-40-2fdb2e9 (MC: 1.21.1)
Other
I'm diagnosing a combat bug caused by this if statement if (amount <= this.lastHurt), what I think it does is it allows the invulnerability timer to be bypassed if a player receives an attack with more damage(?). Due to #11045 this has caused a bug on our server where if you reduce the damage (amount) in the EntityDamageEvent, this if statement will always be false, and players will always receive damage, bypassing the invulnerability timer.
My workaround is to make sure that the amount stored in this.lastHurt is always the original amount (see screenshot), but I'm not sure if this is the best solution. Possibly a PreDamageEvent could make sense here? Any thoughts?
Expected behavior
Reducing the damage in EntityDamageByEntityEvent has no side effects and just reduces the damage.
Observed/Actual behavior
If the damage is reduced in EntityDamageByEntityEvent, the invulnerability timer for an entity is bypassed for subsequent attacks, due to a mismatch in how Paper calculates the most recent attack damage (lastHurt)
Steps/models to reproduce
Add a listener to EntityDamageByEntityEvent to multiply the damage by 0.9.
Place a breakpoint at LivingEntity.java#1470 (at
return false):If you spam click an entity, verify that this the breakpoint at 1470 is never hit with the listener, but is hit without.
Plugin and Datapack List
N/A
Paper version
This server is running Paper version 1.21.1-119-master@7cd4f2c (2024-10-03T15:19:34Z) (Implementing API version 1.21.1-R0.1-SNAPSHOT)
You are running the latest version
Previous version: 1.21.1-40-2fdb2e9 (MC: 1.21.1)
Other
I'm diagnosing a combat bug caused by this if statement
if (amount <= this.lastHurt), what I think it does is it allows the invulnerability timer to be bypassed if a player receives an attack with more damage(?). Due to #11045 this has caused a bug on our server where if you reduce the damage (amount) in the EntityDamageEvent, this if statement will always be false, and players will always receive damage, bypassing the invulnerability timer.My workaround is to make sure that the amount stored in this.lastHurt is always the original amount (see screenshot), but I'm not sure if this is the best solution. Possibly a PreDamageEvent could make sense here? Any thoughts?