php中使用empty/unset去清空变量的warning

Note: empty()/unset() only checks variables as anything else will result in a parse error. In other words, the following will not work: empty(trim($name)).

所以

if(!$this->odwp_empty() &&
            array_key_exists($action->odwp_get_key())){
            unset($action->odwp_get_key());
}

要变成

$key = $action->odwp_get_key();
if(!$this->odwp_empty() &&
            array_key_exists($key)){
            unset($key);
}