Code in maria_ft_boolean_check_syntax_string() uses sizeof(ft_boolean_syntax), most probably to compute its length. It made sense at the time that code was written, since ft_boolean_syntax had char[15] type. Then at some point type of ft_boolean_syntax was changed to const char *, but maria_ft_boolean_check_syntax_string() still uses sizeof(ft_boolean_syntax).

The issue is trivial, since maria_ft_boolean_check_syntax_string() function is not used anywhere.