Prefer placeholder option over empty_value #16885
Description
A placeholder option value should be preferred to empty_value if both are
set in a choice type.
An example of a choice type having values for both options is a form class
which declares a LexikFormFilterBundle filter_boolean type field in a Symfony
2.8 project:-
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder
->add('foo', 'filter_boolean', array(
'choices' => array( ... ),
'placeholder' => 'Some Placeholder',
))But the Lexik filter_boolean type defines a default empty_value option:-
public function getParent()
{
return 'choice';
}
public function configureOptions(OptionsResolver $resolver)
{
$resolver
->setDefaults(array(
'required' => false,
'choices' => array(
self::VALUE_YES => 'boolean.yes',
self::VALUE_NO => 'boolean.no',
),
'empty_value' => 'boolean.yes_or_no',The result is that the placeholder is ignored and empty_value is used.
Clearly the Lexik type needs to be updated, but this issue causes trouble for
developers who update their application code while waiting for the project
dependencies to catch-up.
PR follows.