JsonapiTestFieldAccessHooks.php

<?php

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

use Drupal\Core\Access\AccessResult;
use Drupal\Core\Session\AccountInterface;
use Drupal\Core\Field\FieldDefinitionInterface;
use Drupal\Core\Hook\Attribute\Hook;

/**
 * Hook implementations for jsonapi_test_field_access.
 */
class JsonapiTestFieldAccessHooks {
    
    /**
     * Implements hook_entity_field_access().
     */
    public function entityFieldAccess($operation, FieldDefinitionInterface $field_definition, AccountInterface $account) {
        // @see \Drupal\Tests\jsonapi\Functional\ResourceTestBase::testRelationships().
        if ($field_definition->getName() === 'field_jsonapi_test_entity_ref') {
            // Forbid access in all cases.
            $permission = "field_jsonapi_test_entity_ref {$operation} access";
            $access_result = $account->hasPermission($permission) ? AccessResult::allowed() : AccessResult::forbidden("The '{$permission}' permission is required.");
            return $access_result->addCacheContexts([
                'user.permissions',
            ]);
        }
        // No opinion.
        return AccessResult::neutral();
    }

}