How to create entity reference field from custom entity to another custom entity?

Question

I'm on Drupal 8 and I created a custom entity custom_entity_one following the Drupal 8 examples, the content_entity_example module. Now, in another custom entity, custom_entity_two I'm trying to create a BaseFieldDefinition like so:

$fields['cid'] = BaseFieldDefinition::create('entity_reference')
  ->setLabel(t('custom_entity_one ID'))
  ->setSettings(array(
    'target_type' => 'custom_entity_one',
    'multiple' => TRUE,
    'handler' => 'default'
  ))
  ->setDisplayOptions('view', array(
    'label' => 'above',
    'type' => 'id',
    'weight' => -1,
  ))
  ->setDisplayOptions('form', array(
    'type' => 'entity_reference_autocomplete',
    'settings' => array(
      'match_operator' => 'CONTAINS',
      'size' => 60,
      'placeholder' => '',
    ),
    'weight' => -1,
  ))
  ->setDisplayConfigurable('form', TRUE)
  ->setDisplayConfigurable('view', TRUE);

In the add form of the custom_entity_two, the reference field appears, however, it doesn't find any value, even though I have multiple entities of type custom_entity_one.

I thought that it will look for the label propriety of the entity, but it doesn't seem so. What I am missing ? Should I create a custom handler ? I'm not very sure how.

Answer 1

Yes, I was right, right after I posted the question I checked if I'm missing the entity_key label, and I was. I added it in the entity annotation definition, like so:

entity_keys = {
  "id" = "id",
  "uuid" = "uuid",
  "label" = "title",
},