Comment 9 for bug 1533482

Laurynas,

Hmm... actually it is not even flag:

/**
  Only the plugins that are known to use the mysql.user table
  to store their passwords support password expiration atm.
  TODO: create a service and extend the plugin API to support
  password expiration for external plugins.

  @retval false expiration not supported
  @retval true expiration supported
*/
bool auth_plugin_supports_expiration(const char *plugin_name)
{
 return (!plugin_name || !*plugin_name ||
         plugin_name == native_password_plugin_name.str
#if defined(HAVE_OPENSSL)
         || plugin_name == sha256_password_plugin_name.str
#endif
         );
}

It is checked in sql_auth_cache.cc / acl_load():

        if (table->s->fields > table_schema->password_expired_idx())
        {
          char *tmpstr= get_field(&global_acl_memory,
                           table->field[table_schema->password_expired_idx()]);
          if (tmpstr && (*tmpstr == 'Y' || *tmpstr == 'y'))
          {
            user.password_expired= true;

            if (!auth_plugin_supports_expiration(user.plugin.str))
            {
              sql_print_warning("'user' entry '%s@%s' has the password ignore "
                                "flag raised, but its authentication plugin "
                                "doesn't support password expiration. "
                                "The user id will be ignored.",
                                user.user ? user.user : "",
                                user.host.get_host() ? user.host.get_host() : "");
              continue;
            }
            password_expired= true;
          }
        }

But probably correct flag would be AUTH_FLAG_USES_INTERNAL_STORAGE and one place actually is using it for that purpose (set_and_validate_user_attributes in sql_user.cc):

    if (!(auth->authentication_flags & AUTH_FLAG_USES_INTERNAL_STORAGE))
    {
      if (thd->lex->sql_command == SQLCOM_SET_OPTION)
      {
        /*
          A plugin that does not use internal storage and
          hence does not support SET PASSWORD
        */
        char warning_buffer[MYSQL_ERRMSG_SIZE];
        my_snprintf(warning_buffer, sizeof(warning_buffer),
                    "SET PASSWORD has no significance for user '%s'@'%s' as "
                    "authentication plugin does not support it.",
                    Str->user.str, Str->host.str);
        warning_buffer[MYSQL_ERRMSG_SIZE-1]= '\0';
        push_warning(thd, Sql_condition::SL_NOTE,
                     ER_SET_PASSWORD_AUTH_PLUGIN,
                     warning_buffer);
        plugin_unlock(0, plugin);
        what_to_set= NONE_ATTR;
        return (0);
      }
    }