moduleapi: If path name ends with '-cache' create table as weak (keys and values)

core/moduleapi.lua

@@ -155,6 +155,9 @@ function api:shared(...)
 		local shared = shared_data[path];
 		if not shared then
 			shared = {};
+			if path:match("%-cache$") then
+				setmetatable(shared, { __mode = "kv" });
+			end
 			shared_data[path] = shared;
 		end
 		t_insert(data_array, shared);
@@ -336,4 +339,4 @@ function api:load_resource(path, mode)
 	return io.open(path, mode);
 end
 
-return api;
+return api;