Shulker duplicate event (#10135)

patches/api/0457-Add-ShulkerDuplicateEvent.patch

@@ -0,0 +1,83 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Chase Henderson <henderson.chase@gmail.com>
+Date: Fri, 5 Jan 2024 03:50:10 -0500
+Subject: [PATCH] Add ShulkerDuplicateEvent
+
+
+diff --git a/src/main/java/io/papermc/paper/event/entity/ShulkerDuplicateEvent.java b/src/main/java/io/papermc/paper/event/entity/ShulkerDuplicateEvent.java
+new file mode 100644
+index 0000000000000000000000000000000000000000..1fd54ca6bff3a61b8dfde3350216045376d00ca9
+--- /dev/null
++++ b/src/main/java/io/papermc/paper/event/entity/ShulkerDuplicateEvent.java
+@@ -0,0 +1,71 @@
++package io.papermc.paper.event.entity;
++
++import org.bukkit.entity.Shulker;
++import org.bukkit.event.Cancellable;
++import org.bukkit.event.HandlerList;
++import org.bukkit.event.entity.EntityEvent;
++import org.jetbrains.annotations.ApiStatus;
++import org.jetbrains.annotations.NotNull;
++
++/**
++ * Fired when a shulker duplicates itself by spawning a new shulker.
++ * <p>
++ * The event is fired prior to the newly created shulker, accessible via {@link #getEntity()}, being added to the world.
++ */
++public class ShulkerDuplicateEvent extends EntityEvent implements Cancellable {
++
++    private static final HandlerList HANDLER_LIST = new HandlerList();
++
++    private final Shulker parent;
++    private boolean cancelled;
++
++    @ApiStatus.Internal
++    public ShulkerDuplicateEvent(@NotNull Shulker child, @NotNull Shulker parent) {
++        super(child);
++        this.parent = parent;
++    }
++
++    /**
++     * Provides the newly created shulker, which did not exist prior to the duplication.
++     * At the point of this event, said shulker is not part of the world yet.
++     *
++     * @return the newly duplicated shulker.
++     */
++    @Override
++    @NotNull
++    public Shulker getEntity() {
++        return (Shulker) entity;
++    }
++
++    /**
++     * Provides the "parent" of the freshly created shulker.
++     * The parent shulker is the one that initiated the duplication.
++     *
++     * @return the previously existing shulker which duplicated.
++     */
++    @NotNull
++    public Shulker getParent() {
++        return parent;
++    }
++
++    @Override
++    public boolean isCancelled() {
++        return cancelled;
++    }
++
++    @Override
++    public void setCancelled(boolean cancel) {
++        this.cancelled = cancel;
++    }
++
++    @NotNull
++    @Override
++    public HandlerList getHandlers() {
++        return HANDLER_LIST;
++    }
++
++    @NotNull
++    public static HandlerList getHandlerList() {
++        return HANDLER_LIST;
++    }
++}

patches/server/1042-Add-ShulkerDuplicateEvent.patch

@@ -0,0 +1,22 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Chase Henderson <henderson.chase@gmail.com>
+Date: Fri, 5 Jan 2024 03:50:10 -0500
+Subject: [PATCH] Add ShulkerDuplicateEvent
+
+
+diff --git a/src/main/java/net/minecraft/world/entity/monster/Shulker.java b/src/main/java/net/minecraft/world/entity/monster/Shulker.java
+index b73dac8f68041f8a2e0752d70cc9d08b5cfd1cde..f3c2a2ffb74daa89a516db4c188ce675c79932bf 100644
+--- a/src/main/java/net/minecraft/world/entity/monster/Shulker.java
++++ b/src/main/java/net/minecraft/world/entity/monster/Shulker.java
+@@ -484,6 +484,11 @@ public class Shulker extends AbstractGolem implements VariantHolder<Optional<Dye
+                 if (entityshulker != null) {
+                     entityshulker.setVariant(this.getVariant());
+                     entityshulker.moveTo(vec3d);
++                    // Paper start - Shulker duplicate event
++                    if (!new io.papermc.paper.event.entity.ShulkerDuplicateEvent((org.bukkit.entity.Shulker) entityshulker.getBukkitEntity(), (org.bukkit.entity.Shulker) this.getBukkitEntity()).callEvent()) {
++                        return;
++                    }
++                    // Paper end - Shulker duplicate event
+                     this.level().addFreshEntity(entityshulker, org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.BREEDING); // CraftBukkit - the mysteries of life
+                 }
+