There is different logic (getters, setters) related to AUTHID spread around sql_class.h, sp.h, etc. as well as within the AUTHID class member functions as well.

See: set_invoker, get_definer in sql_class.h.

There is no constructor defined for AUTHID and it is possible to bring it into an inconsistent state. Refactor this code to make AUTHID self contained have code use it with its presented interface only.