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ItemStack Loader

ItemStack Loader is a workaround for loading the Bukkit ItemStack.

caution

Before using this feature, you MUST create a full server backup. After you enable it, changes are written permanently to worlds and databases; rollback is impossible without a backup.

When is this feature required​

When you update to Minecraft to a newer versions and downgrade after that (but without quickshop database), you may see the errors like this:

[Server] ERROR Could not call method 'public static org.bukkit.inventory.ItemStack org.bukkit.inventory.ItemStack.deserialize(java.util.Map)' of class org.bukkit.inventory.ItemStack for deserialization
[Server] INFO java.lang.IllegalArgumentException: Newer version! Server downgrades are not supported!

In this case, our recommendation is to restore the last normal QuickShop database backup, but if you are unfortunate enough to lose all your backups, here is a workaround you can try.

QuickShop will prompt on the console when an error is detected as a result of a version downgrade, such as the following:

[QuickShop-Hikari] [WARN] Cannot load ItemStack {ITEM_INFO} because it was saved by a newer Minecraft server version. The action will fail and you will receive an exception. PLEASE DON'T REPORT THIS TO QUICKSHOP!
[QuickShop-Hikari] [WARN] You can try force load this ItemStack by our hacked ItemStack read util(shop.force-load-downgrade-items), but beware, the data may damaged if you load on this lower Minecraft server version, Please backup your world and database before enable!

Turn on workaround​

Enable the loader workaround by changing the following setting in config.yml:

shop:
  # Cross-Version Item Loading (Advanced / Risky)
  # Attempts to load items created on newer Minecraft versions.
  # WARNING: This may corrupt server or shop data. Always backup first.
  force-load-downgrade-items:
    enable: true
    # Work mode:
    # 0 = Ask Bukkit to update the ItemStack
    # 1 = Ask Bukkit to load the ItemStack directly
    method: 0

Method 0 asks Bukkit to update the ItemStack version, while method 1 asks Bukkit to load it directly. By default, the value is 0.