symfony - Twig Form Theming - form_label class attribute -

i've been trying override form_row twig extension can render twitter bootstrap style row. twitter boostrap form row should this:

<div class="control-group">     <label class="control-label" for="idofmaininput">label name:</label>     <div class="controls">         <input type="text" id="idofmaininput" name="somedumbname">     </div> </div> 

the base twig div style form_row block defined in this link below:

{% block form_row %} {% spaceless %}     <div>         {{ form_label(form) }}         {{ form_errors(form) }}         {{ form_widget(form) }}     </div> {% endspaceless %} {% endblock form_row %} 

so, thoughts put necessary divs in, , hard code necessary class entries (i.e. in main div) pass 'attr' value form_label, form_errors , form_widget sections. i've taken out form_errors now, don't deep it. here's tried:

{% form_theme form _self %} {% block form_row %} {% spaceless %} <div class="control-group">     {{ form_label(form, 'test label name', { 'attr': {'class': 'control-label'} }) }}     <div class="controls">     {{ form_widget(form) }}     {{ form_errors(form) }}     </div> </div> {% endspaceless %} {% endblock form_row %} 

the problem, though, no matter try, form_label extension not use "control-label" class (and should according source code append if there's existing ones, "required"). here's when view source of rendered page:

<div class="control-group">     <label for="form_rsa_id" class="required">test label name</label>     <div class="controls">         <input type="number" id="form_rsa_id" name="form[rsa_id]" required="required" />     </div> </div> 

as can see, class="required" there , taken base form object attributes, should class="required control-label", it's not.

kinda @ loss here, documentation (as source) states 1 should use notation "form_label(view, label, variables)". link docs here.

i think need use label_attr rather attr.