minetest-i4/i3/init.lua

-- This is a placeholder mod, to mimic i3’s presence for mods that test for it.
-- It also migrates data from i3 to i4.

local storage = core.get_mod_storage("i3")
local data = core.deserialize(storage:get_string"data") or {}

if data and not i4.imported then
	-- i3 stores all user-data in a mod-data table; we copy it verbatim to i4.
	i4.data = data

	-- By default, i4’s inventory-size is 32; i3’s, however, is 36. i4 will
	-- default to 36 at init-time if data was imported from i3. But since we’re
	-- only importing now (and i4 has already been initialized), we need to do
	-- it ourselves this time.
	if not i4.settings.inventory_size then
		i4.settings.inventory_size = 36
	end

	-- Mark data as imported, so we don’t go through this song-and-dance again.
	i4.imported = true
end