From e29ea4563988afad5d652acb040d1c25b39276d4 Mon Sep 17 00:00:00 2001
From: Newwind <support@newwindserver.com>
Date: Mon, 26 Aug 2024 14:01:37 +0200
Subject: [PATCH] Check dead flag in isAlive()

If a plugin sets the health of a living entity above 0 after it has already died, the entity will be "revived".
It will behave the exact same as before, except with the internal "dead" flag set, resulting in 2 behavior changes,
A: it's completely invulnerable to all damage
B: it's unable to pickup items

isValid() for these bugged entities will return true, isDead() will return false, despite the dead flag.
This patch checks that the mob isn't dead before saying its alive.

Also, even if the plugin is responsibly checking !isDead() before modifying health, on very rare circumstances
I am currently unable to replicate, these "revived" entities can still appear
---
 .../world/entity/LivingEntity.java.patch      | 38 ++++++++++++-------
 1 file changed, 24 insertions(+), 14 deletions(-)

diff --git a/paper-server/patches/sources/net/minecraft/world/entity/LivingEntity.java.patch b/paper-server/patches/sources/net/minecraft/world/entity/LivingEntity.java.patch
index cc3cd72e6d..11250d126b 100644
--- a/paper-server/patches/sources/net/minecraft/world/entity/LivingEntity.java.patch
+++ b/paper-server/patches/sources/net/minecraft/world/entity/LivingEntity.java.patch
@@ -1065,6 +1065,15 @@
      public Optional<BlockPos> getLastClimbablePos() {
          return this.lastClimbablePos;
      }
+@@ -1718,7 +2152,7 @@
+ 
+     @Override
+     public boolean isAlive() {
+-        return !this.isRemoved() && this.getHealth() > 0.0F;
++        return !this.isRemoved() && this.getHealth() > 0.0F && !this.dead; // Paper - Check this.dead
+     }
+ 
+     public boolean isLookingAtMe(LivingEntity entity, double d0, boolean flag, boolean visualShape, double... checkedYs) {
 @@ -1757,9 +2191,14 @@
          int i = this.calculateFallDamage(fallDistance, damageMultiplier);
  
@@ -1165,7 +1174,7 @@
 +                    int i = (LivingEntity.this.getEffect(MobEffects.DAMAGE_RESISTANCE).getAmplifier() + 1) * 5;
 +                    int j = 25 - i;
 +                    float f1 = f.floatValue() * (float) j;
- 
++
 +                    return -(f - Math.max(f1 / 25.0F, 0.0F));
 +                }
 +                return -0.0;
@@ -1236,7 +1245,7 @@
 +                float armorDamage = (float) (event.getDamage() + event.getDamage(DamageModifier.BLOCKING) + event.getDamage(DamageModifier.HARD_HAT));
 +                this.hurtArmor(damagesource, armorDamage);
 +            }
-+
+ 
 +            // Apply blocking code // PAIL: steal from above
 +            if (event.getDamage(DamageModifier.BLOCKING) < 0) {
 +                this.hurtCurrentlyUsedShield((float) -event.getDamage(DamageModifier.BLOCKING));
@@ -1317,26 +1326,27 @@
      }
  
      public CombatTracker getCombatTracker() {
-@@ -1935,8 +2546,18 @@
+@@ -1935,9 +2546,19 @@
      }
  
      public final void setArrowCount(int stuckArrowCount) {
 -        this.entityData.set(LivingEntity.DATA_ARROW_COUNT_ID, stuckArrowCount);
 +        // CraftBukkit start
 +        this.setArrowCount(stuckArrowCount, false);
-+    }
-+
+     }
+ 
 +    public final void setArrowCount(int i, boolean flag) {
 +        ArrowBodyCountChangeEvent event = CraftEventFactory.callArrowBodyCountChangeEvent(this, this.getArrowCount(), i, flag);
 +        if (event.isCancelled()) {
 +            return;
 +        }
 +        this.entityData.set(LivingEntity.DATA_ARROW_COUNT_ID, event.getNewAmount());
-     }
++    }
 +    // CraftBukkit end
- 
++
      public final int getStingerCount() {
          return (Integer) this.entityData.get(LivingEntity.DATA_STINGER_COUNT_ID);
+     }
 @@ -1999,7 +2620,7 @@
                      this.playSound(soundeffect, this.getSoundVolume(), (this.random.nextFloat() - this.random.nextFloat()) * 0.2F + 1.0F);
                  }
@@ -1346,19 +1356,19 @@
                      this.setHealth(0.0F);
                      this.die(this.damageSources().generic());
                  }
-@@ -2181,6 +2802,12 @@
-     public abstract Iterable<ItemStack> getArmorSlots();
+@@ -2182,6 +2803,12 @@
  
      public abstract ItemStack getItemBySlot(EquipmentSlot slot);
-+
+ 
 +    // CraftBukkit start
 +    public void setItemSlot(EquipmentSlot enumitemslot, ItemStack itemstack, boolean silent) {
 +        this.setItemSlot(enumitemslot, itemstack);
 +    }
 +    // CraftBukkit end
- 
++
      public abstract void setItemSlot(EquipmentSlot slot, ItemStack stack);
  
+     public Iterable<ItemStack> getHandSlots() {
 @@ -2292,17 +2919,29 @@
          return this.hasEffect(MobEffects.JUMP) ? 0.1F * ((float) this.getEffect(MobEffects.JUMP).getAmplifier() + 1.0F) : 0.0F;
      }
@@ -1461,8 +1471,7 @@
 -        while (this.yBodyRot - this.yBodyRotO < -180.0F) {
 -            this.yBodyRotO -= 360.0F;
 -        }
-+        this.xRotO += Math.round((this.getXRot() - this.xRotO) / 360.0F) * 360.0F;
- 
+-
 -        while (this.yBodyRot - this.yBodyRotO >= 180.0F) {
 -            this.yBodyRotO += 360.0F;
 -        }
@@ -1474,7 +1483,8 @@
 -        while (this.getXRot() - this.xRotO >= 180.0F) {
 -            this.xRotO += 360.0F;
 -        }
--
++        this.xRotO += Math.round((this.getXRot() - this.xRotO) / 360.0F) * 360.0F;
+ 
 -        while (this.yHeadRot - this.yHeadRotO < -180.0F) {
 -            this.yHeadRotO -= 360.0F;
 -        }