Twig form_theme _self customizing individual field

Question

I've got a view where I'm trying to override the form theme for an individual field per http://symfony.com/doc/current/cookbook/form/form_customization.html#how-to-customize-an-individual-field.

The view looks something like this:

{% form_theme form _self %}

{% block _my_form_foo_widget %}
    <div class="input-append">
        {{ block('number_widget') }}
        <span class="add-on">%</span>
    </div>
{% endblock %}

<form>
    {{ form_row(form.foo) }}
    {{ form_row(form.bar) }}
</form>

Everything looks as expected for the foo and bar rows, however, the _my_form_foo_widget block itself is also included in the output, i.e.:

<div class="input-append">
    <span class="add-on">%</span>
</div>

<form>
    <div>
        <label for="my_form_foo">Bar</label>
        <div class="input-append">
            <input type="text" id="my_form_foo" name="my_form[foo]">
            <span class="add-on">%</span>
        </div>
    </div>
    <div>
        <label for="my_form_bar">Foo</label>
        <input type="text" id="my_form_bar" name="my_form[bar]">
    </div>
</form>

I can't for the life of my figure out what I'm doing wrong. As a workaround I just wrapped the block in HTML comments.

I'm on Symfony 2.4.1 and Twig 1.15.0.

did you clear your cache? Maybe it's a twig parsing error related to the % sign. Have you tried changing the % in the <span> to a different character (i.e. +) yet? If that works you could try replacing the % with {{ '%' }}. Further you could try to move the overriding block to a distinct template (i.e. form_theme.html.twig ) and use {% form_theme form 'form_theme.html.twig' %} — Nicolai Fröhlich
@nifr Clearing the cache and changing the % to something else makes no difference. — enoshixi
you did not try my suggestion with the external form_theme :) you're not extending another template - that's why the block gets rendered directly. — Nicolai Fröhlich
Yeah, I didn't want to use an external form_theme. I wanted to be able to put the "one-off" type row/widget customizations in the same file as their form. — enoshixi

Nicolai Fröhlich Nicolai Fröhlich · Accepted Answer · 2014-01-29T22:45:05

You are experiencing twig's expected behaviour.

A newly defined block is being rendered directly in the current template if you're not extending another template.

Example:

template_A.html.twig:

has a body (= code outside of blocks) => blocks rendered directly

<html>
<body>
{% block content -%}
Foo
{%- endblock -%} 

Bar

{%- block more_content -%}
Foo
{%- endblock %}
</body>
</html>

=> ouputs: FooBarFoo ( all blocks present in the template + body is being rendered )

Example:

template_B.html.twig:

extending template is not allowed to have a body
will only render blocks that are present in template_A.html.twig

{% extends 'templateA.html.twig' %} 

{% block content -%}
Bar
{%- endblock %}

{% block not_in_template_a %}
Some String
{% endblock %}

=> outputs: BarBarFoo (but does not render Some String because the block not_in_template_a was not present in the original template)

Twig form_theme _self customizing individual field

1 Answers