Added keep on death methods for items (#5395)

src/item/Item.php

@@ -65,6 +65,8 @@ class Item implements \JsonSerializable{
 	public const TAG_DISPLAY_NAME = "Name";
 	public const TAG_DISPLAY_LORE = "Lore";
 
+	public const TAG_KEEP_ON_DEATH = "minecraft:keep_on_death";
+
 	private ItemIdentifier $identifier;
 	private CompoundTag $nbt;
 
@@ -96,6 +98,8 @@ class Item implements \JsonSerializable{
 	 */
 	protected $canDestroy;
 
+	protected bool $keepOnDeath = false;
+
 	/**
 	 * Constructs a new Item type. This constructor should ONLY be used when constructing a new item TYPE to register
 	 * into the index.
@@ -222,6 +226,17 @@ class Item implements \JsonSerializable{
 		}
 	}
 
+	/**
+	 * Returns whether players will retain this item on death. If a non-player dies it will be excluded from the drops.
+	 */
+	public function keepOnDeath() : bool{
+		return $this->keepOnDeath;
+	}
+
+	public function setKeepOnDeath(bool $keepOnDeath) : void{
+		$this->keepOnDeath = $keepOnDeath;
+	}
+
 	/**
 	 * Returns whether this Item has a non-empty NBT.
 	 */
@@ -320,6 +335,8 @@ class Item implements \JsonSerializable{
 				$this->canDestroy[$entry->getValue()] = $entry->getValue();
 			}
 		}
+
+		$this->keepOnDeath = $tag->getByte(self::TAG_KEEP_ON_DEATH, 0) !== 0;
 	}
 
 	protected function serializeCompoundTag(CompoundTag $tag) : void{
@@ -377,6 +394,12 @@ class Item implements \JsonSerializable{
 		}else{
 			$tag->removeTag("CanDestroy");
 		}
+
+		if($this->keepOnDeath){
+			$tag->setByte(self::TAG_KEEP_ON_DEATH, 1);
+		}else{
+			$tag->removeTag(self::TAG_KEEP_ON_DEATH);
+		}
 	}
 
 	public function getCount() : int{