Config entity form field with multiple/unlimited cardinality

Question

I have a config entity form that has a taxonomy field, and it currently works with 1 term

$form['integration'] = array(
  '#type' => 'entity_autocomplete',
  '#title' => 'Integration',
  '#required' => TRUE,
  '#target_type' => 'taxonomy_term',
  '#default_value' => $entity->getIntegration(),
  '#selection_settings' => array(
    'target_bundles' => array(
      'integration',
    ),
  ),
);

That works fine, but I need to be able to select multiple terms, I've tried setting '#cardinality' => -1, but it's only allowing 1 element. I added a taxonomy field with unlimited cardinality to a content type, then set a breakpoint on the form to see how it was being set up for the page rendering. It looks like it creates a container form element, then I assume iterates over an array containing all the terms?

I would have thought there would be a way to set the cardinality of an element by making use of field widgets on the config form page, but I'm not sure that's possible.

Answer 1

(Content) fields have cardinality. There is no such concept for form elements.

However, entity_autcomplete does have a #tags flag, which you can see in the getInfo() method of the class: https://api.drupal.org/api/drupal/core%21lib%21Drupal%21Core%21Entity%21Element%21EntityAutocomplete.php/function/EntityAutocomplete%3A%3AgetInfo/8.

If you set that to TRUE, then it allows you to select a comma-separated list of references.

If you're looking for the "Add another" functionality of entity_autocomplete or any other form element, then you have to build it yourself.