_fix_missing_entities_during_field_purge.php

<?php

/**
 * Temporary function to delete fields attached to entities that have already
 * been deleted. This assumes there are no deleted fields that need to be
 * purged as this won't actually remove their tables in the database. Use with
 * caution and only when fully understanding what this does compared to
 * field_purge_batch and field_purge_field_storage.
 */
function _fix_missing_entities_during_field_purge() {
  /** @var \Drupal\Core\Field\DeletedFieldsRepositoryInterface $deleted_fields_repository */
  $deleted_fields_repository = \Drupal::service('entity_field.deleted_fields_repository');

  $info = \Drupal::entityManager()->getDefinitions();

  $definitions = $deleted_fields_repository->getFieldDefinitions();
  foreach ($definitions as $definition) {
    $entity_type = $definition->getTargetEntityTypeId();
    if (!isset($info[$entity_type])) {
      echo $entity_type . ' '  . $definition->getName() . "\n";
      field_purge_field($definition);
    }
  }

  // Retrieve all deleted field storages. Any that have no fields can be purged.
  foreach ($deleted_fields_repository->getFieldStorageDefinitions() as $field_storage) {
    if (!isset($info[$field_storage->getTargetEntityTypeId()])) {
        echo $field_storage->getTargetEntityTypeId() . ' '  . $field_storage->getName() . "\n";
    }

    $fields = $deleted_fields_repository->getFieldDefinitions($field_storage->getUniqueStorageIdentifier());
    if (empty($fields)) {
      $deleted_fields_repository->removeFieldStorageDefinition($field_storage);

      // Invoke external hooks after the cache is cleared for API consistency.
      \Drupal::moduleHandler()->invokeAll('field_purge_field_storage', [$field_storage]);
    }
  }
}

_fix_missing_entities_during_field_purge();