Paper/patches/server/0781-Correctly-shrink-items-during-EntityResurrectEvent.patch
Bjarne Koll d0dcd7d251
Fix incorrect invulnerability damage reduction (#11599)
Fixes incorrect spigot handling of the invulnerability damage
reduction applied when an already invulnerable entity is damaged with a
larger damage amount than the initial damage.
Vanilla still damages entities even if invulnerable if the damage to be
applied is larger than the previous damage taken. In that case, vanilla
applies the difference between the previous damage taken and the
proposed damage.

Spigot's damage modifier API takes over the computation of damage
reducing effects, however spigot invokes this handling with the initial
damage before computing the difference to the previous damage amount.
This leads to the reduction values to generally be larger than expected,
as they are computed on the not-yet-reduced value.
Spigot applies these reductions after calling the EntityDamageEvent and
*then* subtracts the previous damage point, leading to the final damage
amount being smaller than expected.

This patch cannot simply call the EntityDamageEvent with the reduced
damage, as that would lead to EntityDamageEvent#getDamage() returning
the already reduced damage, which breaks its method contract.
Instead, this patch makes use of the DamageModifier API, implementing
the last-damage-reduction as a DamageModifier.
2024-11-19 11:54:58 +01:00

37 lines
2.0 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Bjarne Koll <git@lynxplay.dev>
Date: Tue, 10 Jan 2023 21:06:42 +0100
Subject: [PATCH] Correctly shrink items during EntityResurrectEvent
The EntityResurrectEvent logic is supposed to locate a totem of undying
in any of the interaction slots of the player inventory and then, if the
called EntityResurrectEvent is not cancelled, shrink that item by 1,
usually reducing it to zero.
For this, the logic iterates over the items in the interaction slots and
breaks out the loop if a totem of undying was found.
However, even if no totem of undying was found, the iteration item stack
variable remains as a refernce to the last interaction slot probed.
Plugins uncancelling a EntityResurrectEvent, which is published
pre-cancelled to listeners if no totem of undying could be found,
would hence cause the server logic to shrink completely unrelated items
found in, at the writing of this patch, the players off hand slot.
This patch corrects this behaviour by only shrinking the item if a totem
of undying was found and the event was called uncancelled.
diff --git a/src/main/java/net/minecraft/world/entity/LivingEntity.java b/src/main/java/net/minecraft/world/entity/LivingEntity.java
index cd2d6b55b494830797014dbc3cc1f0fbf6518249..633c37844062ad93c7241b78663a14a33570c30b 100644
--- a/src/main/java/net/minecraft/world/entity/LivingEntity.java
+++ b/src/main/java/net/minecraft/world/entity/LivingEntity.java
@@ -1672,7 +1672,7 @@ public abstract class LivingEntity extends Entity implements Attackable {
this.level().getCraftServer().getPluginManager().callEvent(event);
if (!event.isCancelled()) {
- if (!itemstack1.isEmpty()) {
+ if (!itemstack1.isEmpty() && itemstack != null) { // Paper - only reduce item if actual totem was found
itemstack1.shrink(1);
}
if (itemstack != null && this instanceof ServerPlayer) {