See the corresponding Bukkit commit for details.
Implementation details:
- Any packets that include an itemstack will send air stacks as null; maybe this will even eliminate the client crash that occurs if the client receives an air stack
- Better handling of null itemstacks in general (ie less converting them to air stacks)
- Inventory.setContents() can now take an array smaller than the inventory without error
- Player.updateInventory() should now correctly update the result slot in a crafting inventory
Some small credit goes to Afforess (initial implementation of openInventory() methods) and Drakia (initial implementation of InventoryOpenEvent and InventoryCloseEvent).
This should fix many issues with enchantments being lost, as the method used takes care of enchantments.
Additionally, use the new nms ItemStack constructor in places where appropriate.
Fixes (at least part of) BUKKIT-7. Need to identify any further places to fix.