(Copied from #6522)

With the current implementation, the attributes passed in the attr option are rendered both in the <form> tag (new) and in the <div>/<table> tag of the form (for BC).

$form = $this->createForm('my_form', $formData, array(
    'attr' => array(
        'id' => 'foo',
        'class' => 'bar',
    ),
));

Template:

{{ form(form) }}

->

<form id="foo" class="bar">
    <div id="foo" class="bar">
        <!-- rows -->
    </div>
</form>

Solutions that come to mind:

(a) Move the rendering of the attributes from the <div>/<table> tag to the <form> tag for the root form. This breaks BC because the form_widget() call for the root form does not output the attributes anymore then. Nested forms are not affected.

<form id="foo" class="bar">
    <div><!-- no attrs! -->
        <!-- rows -->
    </div>
</form>

(b) Don't render a <div> tag for the root form and do as in (a) for the table layout. This obviously also breaks BC. Nested forms are not affected.

<form id="foo" class="bar">
    <!-- rows -->
</form>

(c) Don't render any attributes in the <form> tag. Maintains full BC.

<form>
    <div id="foo" class="bar">
        <!-- rows -->
    </div>
</form>

Opinions?

While (c) is the best solution from a BC point of view, I think it is rather unintuitive. As a newcomer, if I put a "class" attribute on a form, I would expect it to be on the outermost <form> tag, not on some <div> within.

(a) and (b), on the other hand, break BC for those people that use form_widget() to render the complete form. I don't know how many people would be affected by this, this poll tries to gather some data about that. IMO both (a) and (b) are more intuitive and future-proof.

My favorite is (b) because it removes a useless <div> from the default markup.