Override Registered Nodes for Minetest

init.lua

-- The reason this is needed is because the following code does not work as expected:
local  node = minetest.registered_nodes["default:sapling"]
node.after_place_node = function(pos) print("TESTING123") end
minetest.register_node(":default:sapling", node)


--
-- inline solution
--
local node = {}
for k,v in pairs(minetest.registered_nodes["default:sapling"]) do node[k] = v end
node.after_place_node = function(pos) print("TESTING123") end
minetest.register_node(":default:sapling", node)


--
-- global function that can be reused
--

-- function
clone_registered = function(case,name)
	local params = {}
	local list
	if case == "item" then list = minetest.registered_items end
	if case == "node" then list = minetest.registered_nodes end
	if case == "craftitem" then list = minetest.registered_craftitems end
	if case == "tool" then list = minetest.registered_tools end
	if case == "entity" then list = minetest.registered_entities end
	if list then
		for k,v in pairs(list[name]) do
			params[k] = v
		end
	end
	return params
end

-- usage
local node = clone_registered("node","default:tree")
node.after_place_node = function(pos) print("TESTING123") end
minetest.register_node(":default:tree",  node)