[Minor] Fix invocation

diff --git a/lualib/lua_selectors.lua b/lualib/lua_selectors.lua
index 06e23fc80e3dcb77575ce23a8a79cc52391e3b58..00acc4cb249eb9ab76822b6c34a6ce8c76add2ab 100644 (file)
--- a/lualib/lua_selectors.lua
+++ b/lualib/lua_selectors.lua
@@ -716,7 +716,7 @@ exports.create_selector_closure = function(cfg, selector_str, delimiter)
     local res = exports.process_selectors(task, selector)
 
     if res then
-      return exports.combine_selectors(_, res, delimiter)
+      return exports.combine_selectors(nil, res, delimiter)
     end
 
     return nil