Multiple checkboxes in plain subform get double [][]

[rudiedirkx]

My form simplified:

// Prepare subform
$taco_test = $this->formBuilder->plain();
$taco_test->add('professions', 'choice', [
  'label' => trans('report.taco_test.professions'),
  'choices' => $favorites_options,
  'multiple' => TRUE,
  'expanded' => TRUE,
]);

// Add subform to parent
$this->add('taco_test', 'form', [
  'label' => trans('report.taco_test.taco_test'),
  'class' => $taco_test, // the plain form object
]);

So the checkboxes live at form.taco_test.professions, so a single checkbox should be at eg. form.taco_test.professions.66.

The resulting checkboxes have name="taco_test[professions][][]", with a double [][]. Their values are correct.

I know the last [] are added in ChoiceType::buildCheckableChildren(), but maybe it's the first [] that's actually wrong. I've no idea where that comes from.

I'm using 1.6.50 and I'm having some dependency problems, so I can't update in this context to try newer version, but the ChoiceType code seems to be the same in HEAD.

[rudiedirkx]

If I dd($taco_test); before adding it to the parent form, I can see all checkboxes' names:

#name: "professions[]"

That [] comes from buildCheckableChildren() and I think it's correct, so it seems another is added after it... << That doesn't seem to be true, but I really don't get it.

[rudiedirkx]

Temporary local 'fix':

  public function buildForm() {
    // ...
    $this->fixChildFormCheckboxes($this->taco_test->professions);
  }

  protected function fixChildFormCheckboxes(FormField $field) {
    foreach ($field->getChildren() as $child) {
      $child->setName($field->getName());
    }
  }

because form.taco_test.professions's name is correct: taco_test[professions][]. The children shouldn't all get an extra [].

[rudiedirkx]

Still broken, but too complex for me. Work-around: explicit setName() after every plain form creation:

$career_choice_test = $this->formBuilder->plain()->setName('career_choice_test');

and in a subform:

'class' => $this->formBuilder->plain()->setName("career_choice_test[$name]")