#1002: Improve documentation and implementation of getMaxStackSize

By: 2008Choco <hawkeboyz2@hotmail.com>

paper-api/src/main/java/org/bukkit/Material.java

@@ -116,6 +116,8 @@ import org.bukkit.block.data.type.WallHangingSign;
 import org.bukkit.block.data.type.WallSign;
 import org.bukkit.inventory.CreativeCategory;
 import org.bukkit.inventory.EquipmentSlot;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.inventory.meta.ItemMeta;
 import org.bukkit.material.MaterialData;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -4753,7 +4755,12 @@ public enum Material implements Keyed, Translatable {
     }
 
     /**
-     * Gets the maximum amount of this material that can be held in a stack
+     * Gets the maximum amount of this material that can be held in a stack.
+     * <p>
+     * Note that this is the <strong>default</strong> maximum size for this Material.
+     * {@link ItemStack ItemStacks} are able to change their maximum stack size per
+     * stack with {@link ItemMeta#setMaxStackSize(Integer)}. If an ItemStack instance
+     * is available, {@link ItemStack#getMaxStackSize()} may be preferred.
      *
      * @return Maximum stack size for this material
      */

paper-api/src/main/java/org/bukkit/inventory/ItemStack.java

@@ -231,18 +231,21 @@ public class ItemStack implements Cloneable, ConfigurationSerializable, Translat
     }
 
     /**
-     * Get the maximum stacksize for the material hold in this ItemStack.
-     * (Returns -1 if it has no idea)
+     * Get the maximum stack size for this item. If this item has a max stack
+     * size component ({@link ItemMeta#hasMaxStackSize()}), the value of that
+     * component will be returned. Otherwise, this item's Material's {@link
+     * Material#getMaxStackSize() default maximum stack size} will be returned
+     * instead.
      *
-     * @return The maximum you can stack this material to.
+     * @return The maximum you can stack this item to.
      */
     @Utility
     public int getMaxStackSize() {
-        Material material = getType();
-        if (material != null) {
-            return material.getMaxStackSize();
+        if (meta != null && meta.hasMaxStackSize()) {
+            return meta.getMaxStackSize();
         }
-        return -1;
+
+        return getType().getMaxStackSize();
     }
 
     private void createData(final byte data) {