class IdAuditor

class IdAuditor implements AuditorInterface {
    use StringTranslationTrait;
    
    /**
     * {@inheritdoc}
     */
    public function audit(MigrationInterface $migration) {
        // If the migration does not opt into auditing, it passes.
        if (!$migration->isAuditable()) {
            return AuditResult::pass($migration);
        }
        $interface = HighestIdInterface::class;
        $destination = $migration->getDestinationPlugin();
        if (!$destination instanceof HighestIdInterface) {
            throw new AuditException($migration, "Destination does not implement {$interface}");
        }
        $id_map = $migration->getIdMap();
        if (!$id_map instanceof HighestIdInterface) {
            throw new AuditException($migration, "ID map does not implement {$interface}");
        }
        if ($destination->getHighestId() > $id_map->getHighestId() || $destination instanceof EntityContentComplete && !$this->auditEntityComplete($migration)) {
            return AuditResult::fail($migration, [
                $this->t('The destination system contains data which was not created by a migration.'),
            ]);
        }
        return AuditResult::pass($migration);
    }
    
    /**
     * {@inheritdoc}
     */
    public function auditMultiple(array $migrations) {
        $conflicts = [];
        foreach ($migrations as $migration) {
            $migration_id = $migration->getPluginId();
            $conflicts[$migration_id] = $this->audit($migration);
        }
        ksort($conflicts);
        return $conflicts;
    }
    
    /**
     * Audits an EntityComplete migration.
     *
     * @param \Drupal\migrate\Plugin\MigrationInterface $migration
     *   The migration to audit.
     *
     * @return bool
     *   TRUE if the audit passes and FALSE if not.
     *
     * @todo Refactor in https://www.drupal.org/project/drupal/issues/3061676 or
     *   https://www.drupal.org/project/drupal/issues/3091004
     */
    private function auditEntityComplete(MigrationInterface $migration) {
        $map_table = $migration->getIdMap()
            ->mapTableName();
        $database = \Drupal::database();
        if (!$database->schema()
            ->tableExists($map_table)) {
            throw new \InvalidArgumentException();
        }
        $query = $database->select($map_table, 'map')
            ->fields('map', [
            'destid2',
        ])
            ->range(0, 1)
            ->orderBy('destid2', 'DESC');
        $max = (int) $query->execute()
            ->fetchField();
        // Make a migration based on node_complete but with an entity_revision
        // destination.
        $revision_migration = $migration->getPluginDefinition();
        $revision_migration['id'] = $migration->getPluginId() . '-revision';
        $revision_migration['destination']['plugin'] = 'entity_revision:node';
        $revision_migration = \Drupal::service('plugin.manager.migration')->createStubMigration($revision_migration);
        // Get the highest node revision ID.
        $destination = $revision_migration->getDestinationPlugin();
        $highest = $destination->getHighestId();
        return $max <= $highest;
    }

}