1 files changed, 38 insertions, 0 deletions
diff --git a/builtin/game/register.lua b/builtin/game/register.lua
index f330491a2..05dc5fef8 100644
--- a/builtin/game/register.lua
+++ b/builtin/game/register.lua
@@ -7,6 +7,9 @@
 local register_item_raw = core.register_item_raw
 core.register_item_raw = nil
 
+local unregister_item_raw = core.unregister_item_raw
+core.unregister_item_raw = nil
+
 local register_alias_raw = core.register_alias_raw
 core.register_alias_raw = nil
 
@@ -172,6 +175,27 @@ function core.register_item(name, itemdef)
 	register_item_raw(itemdef)
 end
 
+function core.unregister_item(name)
+	if not core.registered_items[name] then
+		core.log("warning", "Not unregistering item " ..name..
+			" because it doesn't exist.")
+		return
+	end
+	-- Erase from registered_* table
+	local type = core.registered_items[name].type
+	if type == "node" then
+		core.registered_nodes[name] = nil
+	elseif type == "craft" then
+		core.registered_craftitems[name] = nil
+	elseif type == "tool" then
+		core.registered_tools[name] = nil
+	end
+	core.registered_items[name] = nil
+
+
+	unregister_item_raw(name)
+end
+
 function core.register_node(name, nodedef)
 	nodedef.type = "node"
 	core.register_item(name, nodedef)
@@ -242,6 +266,20 @@ function core.register_alias(name, convert_to)
 	end
 end
 
+function core.register_alias_force(name, convert_to)
+	if forbidden_item_names[name] then
+		error("Unable to register alias: Name is forbidden: " .. name)
+	end
+	if core.registered_items[name] ~= nil then
+		core.unregister_item(name)
+		core.log("info", "Removed item " ..name..
+			" while attempting to force add an alias")
+	end
+	--core.log("Registering alias: " .. name .. " -> " .. convert_to)
+	core.registered_aliases[name] = convert_to
+	register_alias_raw(name, convert_to)
+end
+
 function core.on_craft(itemstack, player, old_craft_list, craft_inv)
 	for _, func in ipairs(core.registered_on_crafts) do
 		itemstack = func(itemstack, player, old_craft_list, craft_inv) or itemstack