Add EntityPotionTickEvent

paper-api/src/main/java/io/papermc/paper/event/entity/EntityPotionTickEvent.java

@@ -0,0 +1,75 @@
+package io.papermc.paper.event.entity;
+
+import org.bukkit.entity.LivingEntity;
+import org.bukkit.event.Cancellable;
+import org.bukkit.event.HandlerList;
+import org.bukkit.event.entity.EntityEvent;
+import org.bukkit.potion.PotionEffectType;
+import org.jetbrains.annotations.ApiStatus;
+import org.jspecify.annotations.NullMarked;
+
+/**
+ * An event that is triggered when an entity receives a potion effect instantly
+ * or when the potion effect is applied on each tick (e.g. every 25 ticks for Poison level 1).
+ * <p>
+ * For example, this event may be called when an entity regenerates health
+ * or takes poison damage as a result of a potion effect.
+ */
+@NullMarked
+public class EntityPotionTickEvent extends EntityEvent implements Cancellable {
+
+    private static final HandlerList HANDLER_LIST = new HandlerList();
+
+    private final PotionEffectType type;
+    private final int amplifier;
+    private boolean cancelled;
+
+    @ApiStatus.Internal
+    public EntityPotionTickEvent(final LivingEntity entity, final PotionEffectType type, final int amplifier) {
+        super(entity);
+        this.type = type;
+        this.amplifier = amplifier;
+    }
+
+    @Override
+    public LivingEntity getEntity() {
+        return (LivingEntity) super.getEntity();
+    }
+
+    /**
+     * Gets the type of the potion effect associated with this event.
+     *
+     * @return the {@link PotionEffectType} of the effect
+     */
+    public PotionEffectType getType() {
+        return type;
+    }
+
+    /**
+     * Gets the amplifier level of the potion effect associated with this event.
+     *
+     * @return the amplifier level of the potion effect
+     */
+    public int getAmplifier() {
+        return amplifier;
+    }
+
+    @Override
+    public boolean isCancelled() {
+        return this.cancelled;
+    }
+
+    @Override
+    public void setCancelled(final boolean cancel) {
+        this.cancelled = cancel;
+    }
+
+    @Override
+    public HandlerList getHandlers() {
+        return HANDLER_LIST;
+    }
+
+    public static HandlerList getHandlerList() {
+        return HANDLER_LIST;
+    }
+}

paper-server/patches/sources/net/minecraft/world/effect/HealOrHarmMobEffect.java.patch

@@ -9,8 +9,11 @@
          } else {
              entity.hurtServer(level, entity.damageSources().magic(), 6 << amplifier);
          }
-@@ -30,7 +_,7 @@
+@@ -28,9 +_,10 @@
+     public void applyInstantenousEffect(
+         ServerLevel level, @Nullable Entity source, @Nullable Entity indirectSource, LivingEntity entity, int amplifier, double health
      ) {
++        if (!new io.papermc.paper.event.entity.EntityPotionTickEvent(entity.getBukkitLivingEntity(), org.bukkit.craftbukkit.potion.CraftPotionEffectType.minecraftToBukkit(this), amplifier).callEvent()) { return; } // Paper - Add EntityPotionTickEvent
          if (this.isHarm == entity.isInvertedHealAndHarm()) {
              int i = (int)(health * (4 << amplifier) + 0.5);
 -            entity.heal(i);

paper-server/patches/sources/net/minecraft/world/effect/MobEffect.java.patch

@@ -0,0 +1,10 @@
+--- a/net/minecraft/world/effect/MobEffect.java
++++ b/net/minecraft/world/effect/MobEffect.java
+@@ -76,6 +_,7 @@
+     public void applyInstantenousEffect(
+         ServerLevel level, @Nullable Entity source, @Nullable Entity indirectSource, LivingEntity entity, int amplifier, double health
+     ) {
++        if (!new io.papermc.paper.event.entity.EntityPotionTickEvent(entity.getBukkitLivingEntity(), org.bukkit.craftbukkit.potion.CraftPotionEffectType.minecraftToBukkit(this), amplifier).callEvent()) { return; } // Paper - Add EntityPotionTickEvent
+         this.applyEffectTick(level, entity, amplifier);
+     }
+

paper-server/patches/sources/net/minecraft/world/effect/MobEffectInstance.java.patch

@@ -0,0 +1,10 @@
+--- a/net/minecraft/world/effect/MobEffectInstance.java
++++ b/net/minecraft/world/effect/MobEffectInstance.java
+@@ -216,6 +_,7 @@
+             int i = this.isInfiniteDuration() ? entity.tickCount : this.duration;
+             if (entity.level() instanceof ServerLevel serverLevel
+                 && this.effect.value().shouldApplyEffectTickThisTick(i, this.amplifier)
++                && new io.papermc.paper.event.entity.EntityPotionTickEvent(entity.getBukkitLivingEntity(), org.bukkit.craftbukkit.potion.CraftPotionEffectType.minecraftHolderToBukkit(this.effect), this.amplifier).callEvent() // Paper - Add EntityPotionTickEvent
+                 && !this.effect.value().applyEffectTick(serverLevel, entity, this.amplifier)) {
+                 entity.removeEffect(this.effect);
+             }