From dd9cbb74f0bfeac9203e11f681db535cee55a0ef Mon Sep 17 00:00:00 2001
From: "Dylan K. Taylor" <dktapps@pmmp.io>
Date: Sat, 20 Sep 2025 00:01:16 +0100
Subject: [PATCH] Added NeverSavedWithChunkEntity interface closes #6809

turns out we can actually use this for players too.
we need this also for fireworks and probably lightning in the future.
---
 src/entity/Entity.php                    |  2 +-
 src/entity/NeverSavedWithChunkEntity.php | 36 ++++++++++++++++++++++++
 src/player/Player.php                    |  3 +-
 src/world/World.php                      |  3 +-
 4 files changed, 41 insertions(+), 3 deletions(-)
 create mode 100644 src/entity/NeverSavedWithChunkEntity.php

diff --git a/src/entity/Entity.php b/src/entity/Entity.php
index 73a0b3a9c..89f66d6b1 100644
--- a/src/entity/Entity.php
+++ b/src/entity/Entity.php
@@ -492,7 +492,7 @@ abstract class Entity{
 				new FloatTag($this->location->pitch)
 			]));
 
-		if(!($this instanceof Player)){
+		if(!($this instanceof NeverSavedWithChunkEntity)){
 			EntityFactory::getInstance()->injectSaveId(get_class($this), $nbt);
 
 			if($this->getNameTag() !== ""){
diff --git a/src/entity/NeverSavedWithChunkEntity.php b/src/entity/NeverSavedWithChunkEntity.php
new file mode 100644
index 000000000..2245abdd9
--- /dev/null
+++ b/src/entity/NeverSavedWithChunkEntity.php
@@ -0,0 +1,36 @@
+<?php
+
+/*
+ *
+ *  ____            _        _   __  __ _                  __  __ ____
+ * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
+ * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
+ * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
+ * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * @author PocketMine Team
+ * @link http://www.pocketmine.net/
+ *
+ *
+ */
+
+declare(strict_types=1);
+
+namespace pocketmine\entity;
+
+/**
+ * Decorator for entities that will never be saved with a chunk.
+ * Entities implementing this interface are not required to register a save ID.
+ *
+ * This differs from {@link Entity::canSaveWithChunk()} because it can't be changed after the entity is created.
+ * We can't use canSaveWithChunk() to decide whether an entity needs a save ID, but we can use an interface like this.
+ * An attribute would also work, but `instanceof NonSaveable` is easier.
+ */
+interface NeverSavedWithChunkEntity{
+
+}
diff --git a/src/player/Player.php b/src/player/Player.php
index 4468d929e..e44f4c97d 100644
--- a/src/player/Player.php
+++ b/src/player/Player.php
@@ -41,6 +41,7 @@ use pocketmine\entity\Entity;
 use pocketmine\entity\Human;
 use pocketmine\entity\Living;
 use pocketmine\entity\Location;
+use pocketmine\entity\NeverSavedWithChunkEntity;
 use pocketmine\entity\object\ItemEntity;
 use pocketmine\entity\projectile\Arrow;
 use pocketmine\entity\Skin;
@@ -169,7 +170,7 @@ use const PHP_INT_MAX;
 /**
  * Main class that handles networking, recovery, and packet sending to the server part
  */
-class Player extends Human implements CommandSender, ChunkListener, IPlayer{
+class Player extends Human implements CommandSender, ChunkListener, IPlayer, NeverSavedWithChunkEntity{
 	use PermissibleDelegateTrait;
 
 	private const MOVES_PER_TICK = 2;
diff --git a/src/world/World.php b/src/world/World.php
index 236fd6e56..7917ea18c 100644
--- a/src/world/World.php
+++ b/src/world/World.php
@@ -42,6 +42,7 @@ use pocketmine\data\SavedDataLoadingException;
 use pocketmine\entity\Entity;
 use pocketmine\entity\EntityFactory;
 use pocketmine\entity\Location;
+use pocketmine\entity\NeverSavedWithChunkEntity;
 use pocketmine\entity\object\ExperienceOrb;
 use pocketmine\entity\object\ItemEntity;
 use pocketmine\event\block\BlockBreakEvent;
@@ -2776,7 +2777,7 @@ class World implements ChunkManager{
 				throw new AssumptionFailedError("Found two different entities sharing entity ID " . $entity->getId());
 			}
 		}
-		if(!EntityFactory::getInstance()->isRegistered($entity::class) && !$entity instanceof Player){
+		if(!EntityFactory::getInstance()->isRegistered($entity::class) && !$entity instanceof NeverSavedWithChunkEntity){
 			//canSaveWithChunk is mutable, so that means it could be toggled after adding the entity and cause a crash
 			//later on. Better we just force all entities to have a save ID, even if it might not be needed.
 			throw new \LogicException("Entity " . $entity::class . " is not registered for a save ID in EntityFactory");