EntityReferenceTestHooks.php

<?php

declare (strict_types=1);
namespace Drupal\entity_reference_test\Hook;

use Drupal\Core\Field\BaseFieldDefinition;
use Drupal\Core\Entity\EntityTypeInterface;
use Drupal\Core\Hook\Attribute\Hook;

/**
 * Hook implementations for entity_reference_test.
 */
class EntityReferenceTestHooks {
    
    /**
     * Implements hook_entity_base_field_info().
     */
    public function entityBaseFieldInfo(EntityTypeInterface $entity_type) {
        $fields = [];
        if ($entity_type->id() === 'entity_test') {
            $fields['user_role'] = BaseFieldDefinition::create('entity_reference')->setLabel(t('User role'))
                ->setDescription(t('The role of the associated user.'))
                ->setSetting('target_type', 'user_role')
                ->setSetting('handler', 'default');
        }
        return $fields;
    }
    
    /**
     * Implements hook_entity_base_field_info_alter().
     */
    public function entityBaseFieldInfoAlter(&$fields, EntityTypeInterface $entity_type) : void {
        if ($entity_type->id() === 'entity_test') {
            // Allow user_id field to use configurable widget.
            $fields['user_id']->setSetting('handler', 'default')
                ->setDisplayOptions('form', [
                'type' => 'entity_reference_autocomplete',
                'weight' => 0,
            ])
                ->setDisplayConfigurable('form', TRUE);
        }
    }

}