How to make a custom entity fieldable?

Question

This has been asked here before; but question is closed and the few replies do not provide sufficient information.

I am trying to use a contrib module (sitewide_alert) which provides its own custom entity. I am trying to figure out how to patch this module to make it fieldable (and how to do this in general).

In other posts I have seen suggestions to add the follinwg to the ContentEntityType annotation:

• fieldable = TRUE;
• bundle_entity_type = ??
• field_ui_base_route -> different suggestions but already exists for this module pointing to the module's config form.

But none of those seemed to fix this.

the full annotation for the entity is:

* @ContentEntityType(
 *   id = "sitewide_alert",
 *   label = @Translation("Sitewide Alert"),
 *   label_plural = @Translation("Sitewide Alerts"),
 *   label_collection = @Translation("Sitewide Alerts"),
 *   handlers = {
 *     "storage" = "Drupal\sitewide_alert\SitewideAlertStorage",
 *     "view_builder" = "Drupal\Core\Entity\EntityViewBuilder",
 *     "list_builder" = "Drupal\sitewide_alert\SitewideAlertListBuilder",
 *     "views_data" = "Drupal\sitewide_alert\Entity\SitewideAlertViewsData",
 *     "translation" = "Drupal\sitewide_alert\SitewideAlertTranslationHandler",
 *
 *     "form" = {
 *       "default" = "Drupal\sitewide_alert\Form\SitewideAlertForm",
 *       "add" = "Drupal\sitewide_alert\Form\SitewideAlertForm",
 *       "edit" = "Drupal\sitewide_alert\Form\SitewideAlertForm",
 *       "delete" = "Drupal\sitewide_alert\Form\SitewideAlertDeleteForm",
 *     },
 *     "route_provider" = {
 *       "html" = "Drupal\sitewide_alert\SitewideAlertHtmlRouteProvider",
 *     },
 *     "access" = "Drupal\sitewide_alert\SitewideAlertAccessControlHandler",
 *   },
 *   base_table = "sitewide_alert",
 *   data_table = "sitewide_alert_field_data",
 *   revision_table = "sitewide_alert_revision",
 *   revision_data_table = "sitewide_alert_field_revision",
 *   show_revision_ui = TRUE,
 *   translatable = TRUE,
 *   admin_permission = "administer sitewide alert entities",
 *   entity_keys = {
 *     "id" = "id",
 *     "revision" = "vid",
 *     "label" = "name",
 *     "uuid" = "uuid",
 *     "uid" = "user_id",
 *     "langcode" = "langcode",
 *     "published" = "status",
 *   },
 *   revision_metadata_keys = {
 *     "revision_user" = "revision_user",
 *     "revision_created" = "revision_created",
 *     "revision_log_message" = "revision_log",
 *   },
 *   links = {
 *     "canonical" = "/admin/content/sitewide_alert/{sitewide_alert}",
 *     "add-form" = "/admin/content/sitewide_alert/add",
 *     "edit-form" = "/admin/content/sitewide_alert/{sitewide_alert}/edit",
 *     "delete-form" = "/admin/content/sitewide_alert/{sitewide_alert}/delete",
 *     "version-history" = "/admin/content/sitewide_alert/{sitewide_alert}/revisions",
 *     "revision" = "/admin/content/sitewide_alert/{sitewide_alert}/revisions/{sitewide_alert_revision}/view",
 *     "revision_revert" = "/admin/content/sitewide_alert/{sitewide_alert}/revisions/{sitewide_alert_revision}/revert",
 *     "revision_delete" = "/admin/content/sitewide_alert/{sitewide_alert}/revisions/{sitewide_alert_revision}/delete",
 *     "translation_revert" = "/admin/content/sitewide_alert/{sitewide_alert}/revisions/{sitewide_alert_revision}/revert/{langcode}",
 *     "collection" = "/admin/content/sitewide_alert",
 *   },
 *   field_ui_base_route = "sitewide_alert.settings",
 *   constraints = {
 *     "ScheduledDateProvided" = {}
 *   }
 * )
 */

In my trial/error approach I did notice I created the Manage Fields/Display/etc UI for each entity I had previously created. So I think this is possibly related to not having a bundle defined? My use case doesn't require making new bundles (similar to the User entity).

Despite the other posted answers; my guess is modifying the annotation is not enough to add this functionality.

Answer 1

There is nothing wrong with the entity type annotation. After you have removed this code intentionally disabling the field UI routes

https://git.drupalcode.org/project/sitewide_alert/-/blob/8.x-1.6/src/Routing/RouteSubscriber.php

the entity should be fieldable at admin/content/sitewide_alert/settings/fields.

This is a very cool module. After playing around a little bit I've found out the module has two settings routes, the mentioned dummy form in an odd place under content and the official module settings form in configuration. If you attach the field UI to this form it's easier to find I think:

field_ui_base_route = "sitewide_alert.sitewide_alert_config_form"