Paper/patches/server/Only-call-EntityDamageEvents-before-actuallyHurt.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Bjarne Koll <git@lynxplay.dev>
Date: Mon, 8 Jul 2024 22:01:08 +0200
Subject: [PATCH] Only call EntityDamageEvents before actuallyHurt

The recent upstream update moved around the event logic for
EntiyDamageEvent and its derivatives.
However, the event was called on every call to #hurt as it was moved out
of actuallyHurt.

This patch moves the invocation directly before the #actuallyHurt calls,
respective invulnerable timings.

diff --git a/src/main/java/net/minecraft/world/entity/LivingEntity.java b/src/main/java/net/minecraft/world/entity/LivingEntity.java
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
--- a/src/main/java/net/minecraft/world/entity/LivingEntity.java
+++ b/src/main/java/net/minecraft/world/entity/LivingEntity.java
@@ -0,0 +0,0 @@ public abstract class LivingEntity extends Entity implements Attackable {
             }
 
             // CraftBukkit start
-            EntityDamageEvent event = this.handleEntityDamage(source, amount);
-            amount = 0;
-            amount += (float) event.getDamage(DamageModifier.BASE);
-            amount += (float) event.getDamage(DamageModifier.BLOCKING);
-            amount += (float) event.getDamage(DamageModifier.FREEZING);
-            amount += (float) event.getDamage(DamageModifier.HARD_HAT);
+            EntityDamageEvent event; // Paper - move this into the actual invuln check....
             // CraftBukkit end
 
             this.walkAnimation.setSpeed(1.5F);
@@ -0,0 +0,0 @@ public abstract class LivingEntity extends Entity implements Attackable {
                     return false;
                 }
 
+                // Paper start - only call damage event when actuallyHurt will be called - move call logic down
+                event = this.handleEntityDamage(source, amount);
+                amount = computeAmountFromEntityDamageEvent(event);
+                // Paper end - only call damage event when actuallyHurt will be called - move call logic down
+
                 // CraftBukkit start
                 if (!this.actuallyHurt(source, (float) event.getFinalDamage() - this.lastHurt, event)) {
                     return false;
@@ -0,0 +0,0 @@ public abstract class LivingEntity extends Entity implements Attackable {
                 this.lastHurt = amount;
                 flag1 = false;
             } else {
+                // Paper start - only call damage event when actuallyHurt will be called - move call logic down
+                event = this.handleEntityDamage(source, amount);
+                amount = computeAmountFromEntityDamageEvent(event);
+                // Paper end - only call damage event when actuallyHurt will be called - move call logic down
                 // CraftBukkit start
                 if (!this.actuallyHurt(source, (float) event.getFinalDamage(), event)) {
                     return false;
@@ -0,0 +0,0 @@ public abstract class LivingEntity extends Entity implements Attackable {
         }
     }
 
+    // Paper start - only call damage event when actuallyHurt will be called - move out amount computation logic
+    private float computeAmountFromEntityDamageEvent(final EntityDamageEvent event) {
+        // Taken from hurt()'s craftbukkit diff.
+        float amount = 0;
+        amount += (float) event.getDamage(DamageModifier.BASE);
+        amount += (float) event.getDamage(DamageModifier.BLOCKING);
+        amount += (float) event.getDamage(DamageModifier.FREEZING);
+        amount += (float) event.getDamage(DamageModifier.HARD_HAT);
+        return amount;
+    }
+    // Paper end - only call damage event when actuallyHurt will be called - move out amount computation logic
+
     protected void blockUsingShield(LivingEntity attacker) {
         attacker.blockedByShield(this);
     }