By timmillwood on
Change record status: 
Published (View all published change records)
Project: 
Drupal core
Introduced in branch: 
8.4.x
Introduced in version: 
8.4.0-beta1
Issue links: 
https://www.drupal.org/node/2721313
Description: 

Before Drupal 8.4, there were only two revisionable entity types in core: Node and BlockContent. To work towards making more entity types revisionable the SqlContentEntityStorageSchemaConverter utility/helper class has been added.

In order to enable revision support for an entity type with existing data, the following post update function can be used as an example:

function <module_name>_post_update_make_revisionable(&$sandbox) {
  $revisionableSchemaConverter = new SqlContentEntityStorageSchemaConverter(
    '<entity_type_name>',
    \Drupal::entityTypeManager(),
    \Drupal::entityDefinitionUpdateManager(),
    \Drupal::service('entity.last_installed_schema.repository'),
    \Drupal::keyValue('entity.storage_schema.sql'),
    \Drupal::database()
  );

  $revisionableSchemaConverter->convertToRevisionable(
    $sandbox,
    [
      '<field_name_that_is_now_revisionable>',
      ...
    ]);
}

More detailed documentation about the upgrade path can be found here: https://www.drupal.org/docs/8/api/entity-api/converting-a-content-entity...

Impacts: 
Module developers