Cuberite Item Multiplication Bug Fix (Survival Mode) Plugin

main.lua

-- Coded by Nixtren
-- Released under Public Domain, it's a very simple plugin.
-- More information: https://github.com/cuberite/cuberite/issues/2272 and https://github.com/cuberite/cuberite/issues/1700

PLUGIN = nil

function Initialize(Plugin)
	Plugin:SetName("ItemMultiplicationBugFix")
	Plugin:SetVersion(4)
	
	-- Hooks
	
	PLUGIN = Plugin -- NOTE: only needed if you want OnDisable() to use GetName() or something like that
	cPluginManager.AddHook(cPluginManager.HOOK_PLAYER_PLACING_BLOCK, OnPlayerPlacingBlock)
	
	-- Command Bindings
	
	-- Other stuff

        LOG("[ItemMultiplicationBugFix] Loaded. This fixes a multiplication bug in Survival Mode. Don't forget to remove this plugin once the problem is internally fixed!")
	return true
end

function OnDisable()
	LOG(PLUGIN:GetName() .. " is shutting down...")
end

function OnPlayerPlacingBlock(Player, BlockX, BlockY, BlockZ, BlockType, BlockMeta)
	if Player:GetGameMode() == gmSurvival then -- The API Docs ask me to use IsGameModeXXX() functions, but I don't really know how to use them :P
        if BlockType == E_BLOCK_BED or BlockType == E_BLOCK_LILY_PAD or BlockType == E_BLOCK_ACACIA_DOOR or BlockType == E_BLOCK_BIRCH_DOOR or BlockType == E_BLOCK_DARK_OAK_DOOR or BlockType == E_BLOCK_IRON_DOOR or BlockType == E_BLOCK_JUNGLE_DOOR or BlockType == E_BLOCK_SPRUCE_DOOR or BlockType == E_BLOCK_WOODEN_DOOR then -- Thanks to Seadragon91 for the list of bugged items (https://github.com/cuberite/cuberite/issues/1700)
            Player:GetInventory():RemoveOneEquippedItem()
        end
    end
end

Doesn't this remove more items for the regular items (that were working before)? It would seem to me that when placing e. g. dirt, the server would remove one and then this plugin would remove another one.

You are correct, I completely forgot about that. I guess this becomes kind of useless unless we add a condition to check if the BlockType is one of the bugged ones. I will edit the plugin soon.

Edit: Plugin updated, should be working without bugs now.

Plugin updated due to a double-spend bug in some cases (when BlockMeta = 0), you should update to version 3 of this plugin ASAP.

Edit: Plugin updated to version 4. Only blocks are safe from multiplication, so an internal fix is really required.