diff --git a/util/util.lua b/util/util.lua
index e611b5c..1b01f6a 100644
--- a/util/util.lua
+++ b/util/util.lua
@@ -189,14 +189,11 @@ util = {
 	-- @treturn table the copied table
 	copy = function(t, cache)
 		if cache == nil then cache = {} end
+		if cache[t] then return cache[t] end
 		local r = {}
 		cache[t] = r
 		for k, v in pairs(t) do
-			if type(v) == "table" then
-				r[k] = cache[v] or util.copy(v, cache)
-			else
-				r[k] = v
-			end
+			r[k] = type(v) == "table" and util.copy(v, cache) or v
 		end
 		return setmetatable(r, getmetatable(t))
 	end,