builtin/../register.lua: Abort make_wrap_deregistration if param is invalid

diff --git a/builtin/game/register.lua b/builtin/game/register.lua
index 3edab0471a6dbc7c2c47126c0307db78f34393ef..d111e5c27450b784d83c564cd158800d5169892a 100644 (file)
--- a/builtin/game/register.lua
+++ b/builtin/game/register.lua
@@ -514,11 +514,17 @@ local function make_registration_wrap(reg_fn_name, clear_fn_name)
 end
 
 local function make_wrap_deregistration(reg_fn, clear_fn, list)
-       local unregister = function (unregistered_key)
+       local unregister = function (key)
+               if type(key) ~= "string" then
+                       error("key is not a string", 2)
+               end
+               if not list[key] then
+                       error("Attempt to unregister non-existent element - '" .. key .. "'", 2)
+               end
                local temporary_list = table.copy(list)
                clear_fn()
                for k,v in pairs(temporary_list) do
-                       if unregistered_key ~= k then
+                       if key ~= k then
                                reg_fn(v)
                        end
                end
@@ -564,7 +570,8 @@ core.registered_biomes      = make_registration_wrap("register_biome",      "cle
 core.registered_ores        = make_registration_wrap("register_ore",        "clear_registered_ores")
 core.registered_decorations = make_registration_wrap("register_decoration", "clear_registered_decorations")
 
-core.unregister_biome = make_wrap_deregistration(core.register_biome, core.clear_registered_biomes, core.registered_biomes)
+core.unregister_biome = make_wrap_deregistration(core.register_biome,
+               core.clear_registered_biomes, core.registered_biomes)
 
 core.registered_on_chat_messages, core.register_on_chat_message = make_registration()
 core.registered_globalsteps, core.register_globalstep = make_registration()