public function onBeforeSetPassword(Event $event)
{
    $user = $event->params['user'];
    $password = $event->params['password'];

    if (mb_strlen($password) < 8)
    {
        $user->addError('password', 'Sorry but your password must be at least 8 characters.');
        $event->performAction = false;
    }
    if (!preg_match('/(d.*[A-Z]|[A-Z].*d)/', $password))
    {
        $user->addError('password', 'Sorry but your password must contain at least one uppercase letter and one number.');
        $event->performAction = false;
    }
}

{% if account is defined and account.getErrors('password') %}
    {% include '_includes/formError' with { error : account.getErrors('password')|join('<br>') } %}
{% endif %}