Fixed in #14465 I guess.

It was fixed partially. but in our case exception happens in ModelChoiceList , before the null/empty check in ChoiceToValueTransformer.

still not fixed, but I can't re-open this ticket now

Same error after submitting optional entity form field type with empty_value with doctrine on Symfony 2.7 (e60f715). Related issues are #14393 and #14465, but non of those fixes seems to fix this issue.

Field definition:

$builder->add('dealer', 'entity', array(
    'label' => 'useraccount.label.dealer',
    'class' => 'MyAppBundle:Subject',
    'choice_label' => 'label',
    'empty_value' => '',
    'multiple' => false,
    'required' => false
));

After submitting empty value i get this error:

SQLSTATE[22P02]: Invalid text representation: 7 ERROR: invalid input syntax for integer: ""

It seems like Symfony is trying to find Subject entity using empty string as id for dealer field:

DBALException: An exception occurred while executing 'SELECT ... FROM subject s0_ WHERE s0_.id IN (?)' with params [""]:

Seems to be the same problem, but fix needs to be done either in ChoiceToValueTransformer (for both model and entity lists) or separately in bridge ChoiceList classes

+1
ChoiceToValueTransformer
Form

$builder->add('country', 'entity', [
            'class' => 'AppBundle\Entity\Country',
            'query_builder' => function (EntityRepository $er) {
                return $er->createQueryBuilder('c')
                    ->orderBy('c.name', 'ASC');
            },
        ]);

If in this case i try save empty value, i have error

An exception occurred while executing 'SELECT c0_.id AS id0, c0_.iso_code AS iso_code1, c0_.name AS name2, c0_.slug AS slug3 FROM country c0_ WHERE c0_.id IN (?) ORDER BY c0_.name ASC' with params [""]:

SQLSTATE[22P02]: Invalid text representation: 7 ERROR: invalid input syntax for integer: ""

If set 'empty_data' => 0,

$builder->add('country', 'entity', [
            'class' => 'AppBundle\Entity\Country',
            'empty_data' => 0,
            'query_builder' => function (EntityRepository $er) {
                return $er->createQueryBuilder('c')
                    ->orderBy('c.name', 'ASC');
            },
        ]);

worked without errors

Symfony version 2.7.0-DEV

@madmis by trying this workaround I get an TransformationFailureException "The choice "0" does not exist or is not unique" and it break my form validation

Symfony 2.7.0 LTS

This happens for me with the placeholder option:

$builder->add('category', null, array(
            'label' => _('Category'),
            'order_by' => 'title',
            'placeholder' => _('none'),
        ));

This bug is fixed for Doctrine in #14950.

That fix solves my issue... although it feels somehow hacky to just filter any non-integers from the values. Shouldn't it be fixed somehow related to empty_data as this is the cause of the empty string?

I just found this issue since I'm getting exactly this problem, but with guid type. I think that guid should be added to the array of types to check.
So, instead of array('integer', 'bigint', 'smallint'), it should be array('integer', 'bigint', 'smallint', 'guid')