Have you tried setting an instance of your entity as data for the form? That should definitely populate the defaults. I also ran into some issues with the empty_data option, but I usually accomplish everything I want from forms without that option. Give data a try.

Have you tried setting an instance of your entity as data for the form?

yes, and it works. but it's not related to the current issue ;)

In any way the empty_data option is not designed to populate the form default. It is supposed to be the value you want when the form is submitted empty.

In any way the empty_data option is not designed to populate the form default. It is supposed to be the value you want when the form is submitted empty.

Exactly, but still, the empty_data value is not propagated to subfields on submit. So what is mentioned in the cookbook is wrong or misunderstood, because in the given example, the empty_data default values of the checkbox and text fields are respectively false and '' (an empty string), which will override the properties of the Foo instance here.

In any way the empty_data option is not designed to populate the form default.

I know, but IMHO it should be.

Yes, I agree the empty_data option does not seem to work. I actually ran into this yesterday myself, which is how I found this issue. I just wanted to separate the discussion of this from setting default values on the form, because I think this is unrelated.

@lyrixx generally in these cases it's recommended setting the default value in the underlying object before binding the form (you can use arrays as underlying object). This way, there would be no need for anything special. (comment)

In your particular case, you can use data option without any problem:

$resolver->setDefaults(array(
    'data_class' => Foo::class,
    'data' => new Foo(),
));

because you do not have an underlying object to the form instance. However it's a common mistake to think that data option works as default value:

$model = new \stdClass();
$model->name = 'foo';

$form = $this->createFormBuilder($model)
    ->add('name', null, ['data' => 'bar'])
    ->add('submit', 'submit')
    ->getForm();

The initial value of the name form field would 'bar' instead of 'foo', because the default values for form fields are taken directly from the underlying data structure (e.g. an entity or an array). The data option overrides this default value. (See doc)

I proposed some time ago, create an option for the default value of the form fields: issue #15334

@lyrixx My current solution for that is to create a form type extension and to add default option for all form fields using FormEvents::PRE_SET_DATA: See example

So your form type will look like this:

$builder
    ->add('enabled', 'checkbox', array('default' => true))
    ->add('name', 'text', array('default' => 'greg')) ;

or like this:

$resolver->setDefaults(array(
    'data_class' => Foo::class,
    'default' => new Foo(),
));

Working in all cases.

I agree that there is an option it to behave in this way, either empty_data or default

@ogizanagi The part which can confuse the cookbook is when they mention that empty_data is used to get the "starting data":

    // no data is passed in, so empty_data is
    // used to get the "starting data"
    $form = $this->createForm(new BlogType());

Because this empty data set would be used if you submit your form only, so never will display this data set, because never will assigned to the form data when this is created.

@yceruto : This is actually confusing, but this is not what I'm pointing in #16530 (comment). :/

data option replaces the default null for populating field, so it's mapped to the view.
empty_data is only mapped if there was no submitted data so it cannot reach the view.

About value="1", this is just the default in CheckboxType see here.

This is an expected behaviour IMO, this issue should be closed and maybe adressed to the doc.

Status: Reviewed

Thanks for looking into this @HeahDude! Care to submit a PR to the docs?

@jakzal sure, I take a look.

Try this (in your FormType file) :
->add('myField', NumberType::class,[ 'empty_data'=>1, 'attr'=>[ 'value'=>1 ] ])