Symfony Bootstrap 4 Form Layout Inheritance - forms

Question

I'm trying to override some fields of bootstrap_4_layout.html.twig, but i found some problems with radio_widget block. I need to change the div element to label, but when I ovverride the block, the radio element is duplicated on view. The div in question is that with class custom-control
{% block radio_widget %}
{% set parent_label_class = parent_label_class|default(label_attr.class|default('')) %}
{% if 'radio-custom' in parent_label_class %}
{% set attr = attr|merge({class: (attr.class|default('') ~ ' custom-control-input')|trim}) %}
<div class="custom-control custom-radio{{ 'radio-inline' in parent_label_class ? ' custom-control-inline' }}">
{{ form_label(form, null, { widget: parent() }) }}
</div>
{% else %}
{% set attr = attr|merge({class: (attr.class|default('') ~ ' form-check-input')|trim}) %}
<div class="form-check{{ 'radio-inline' in parent_label_class ? ' form-check-inline' }}">
{{ form_label(form, null, { widget: parent() }) }}
</div>
{% endif %}
{% endblock radio_widget %}
Analizyng the dom with the console, I see that are created two element with custom-control class. Why?

Answer 1

I found the solution. I override the block radio_widget and changed the div element with label:
{% block radio_widget %}
{% set parent_label_class = parent_label_class|default(label_attr.class|default('')) %}
{% if 'radio-custom' in parent_label_class %}
{% set attr = attr|merge({class: (attr.class|default('') ~ ' custom-control-input')|trim}) %}
<label class="custom-control custom-radio{{ 'radio-inline' in parent_label_class ? ' custom-control-inline' }}">
{{ form_label(form, null, { widget: parent() }) }}
</label>
{% else %}
{% set attr = attr|merge({class: (attr.class|default('') ~ ' form-check-input')|trim}) %}
<div class="form-check{{ 'radio-inline' in parent_label_class ? ' form-check-inline' }}">
{{ form_label(form, null, { widget: parent() }) }}
</div>
{% endif %}
{% endblock radio_widget %}
Then I override also the block checkbox_radio_label. Inside it I substituted the base code:
// ...
{{ widget|raw }}
// ...
With:
{% set attr = attr|merge({class: (attr.class|default('') ~ ' custom-control-input')|trim}) %}
<input type="radio" {{ block('widget_attributes') }}{% if value is defined %} value="{{ value }}"{% endif %}{% if checked %} checked="checked"{% endif %} />
For reference about bootstrap 4 twig blocks see this link:
https://github.com/symfony/symfony/blob/master/src/Symfony/Bridge/Twig/Resources/views/Form/bootstrap_4_layout.html.twig