Control the way form validation errors are displayed in Symfony2

Question

How do I globally change the way form validation errors are displayed in Symfony2? For example, if I want to wrap each one of my error messages in a <span class="error"> or something like that, how would that be done?

Note: I'm aware of this question/answer, but I'm not sure that it's the same question as mine, and I don't understand how to apply the selected answer.

Answer 1

Take a look at the docs: custom global theme, customizing error output

Answer 2

{# SomeBundle:Layout:fields.html.twig #}
{% block field_errors %}
{% spaceless %}
    {% if errors|length > 0 %}
        <span class="error">
            {% for error in errors %}
                {{ error.messageTemplate|trans(error.messageParameters, 'validators') }}<br />
            {% endfor %}
        </span>
    {% endif %}
{% endspaceless %}
{% endblock field_errors %}

{# In your form template #}
{% form_theme form 'SomeBundle:Layout:fields.html.twig' %}