Issue #3300517 by mxh, jurgenhaas: Provide a mechanic for popping off items from a list

   *   The ECA configuration entity to calculate dependencies for.

   * @param array &$dependencies

   *   Current array of dependencies where new dependencies will be added to.

   * @param array &$scanned_ids

   *   An internal list of already scanned components, keyed by component ID.

   *   This list is mainly used to prevent infinite recursion.

   */

  protected function addDependenciesFromComponent(array $component, array &$entity_field_info, Eca $eca, array &$dependencies): void {

  protected function addDependenciesFromComponent(array $component, array &$entity_field_info, Eca $eca, array &$dependencies, array &$scanned_ids = []): void {

    $plugin_id_parts = !empty($component['plugin']) ? explode(':', $component['plugin']) : [];

    foreach ($plugin_id_parts as $id_part) {

      $this->addEntityFieldInfo($id_part, $entity_field_info);

    }

    if (!empty($component['successors'])) {

      foreach ($component['successors'] as $successor) {

        if (empty($successor['id'])) {

        if (!isset($successor['id']) || $successor['id'] === '' || isset($scanned_ids[$successor['id']])) {

          continue;

        }

        $successor_id = $successor['id'];

        foreach (['events', 'conditions', 'actions', 'gateways'] as $prop) {

          $components = $eca->get($prop) ?? [];

          if (isset($components[$successor_id])) {

            $this->addDependenciesFromComponent($components[$successor_id], $entity_field_info, $eca, $dependencies);

            $scanned_ids[$successor_id] = 1;

            $this->addDependenciesFromComponent($components[$successor_id], $entity_field_info, $eca, $dependencies, $scanned_ids);

            break;

          }

        }