findMigrationDependencies example

  public function getMigrationDependencies(bool $expand = FALSE) {
    if (!$expand) {
      @trigger_error('Calling Migration::getMigrationDependencies() without expanding the plugin IDs is deprecated in drupal:10.1.0 and is removed from drupal:11.0.0. In most cases, use getMigrationDependencies(TRUE). See https://www.drupal.org/node/3266691', E_USER_DEPRECATED);
    }
    // @todo Before Drupal 11.0.0, remove ::set() and these checks.     // @see https://www.drupal.org/project/drupal/issues/3262395     $this->migration_dependencies = ($this->migration_dependencies ?: []) + ['required' => [], 'optional' => []];
    if (count($this->migration_dependencies) !== 2 || !is_array($this->migration_dependencies['required']) || !is_array($this->migration_dependencies['optional'])) {
      throw new InvalidPluginDefinitionException($this->id(), "Invalid migration dependencies configuration for migration {$this->id()}");
    }
    $this->migration_dependencies['optional'] = array_unique(array_merge($this->migration_dependencies['optional'], $this->findMigrationDependencies($this->process)));
    if (!$expand) {
      return $this->migration_dependencies;
    }
    return array_map(
      [$this->migrationPluginManager, 'expandPluginIds'],
      $this->migration_dependencies
    );
  }

  /** * Find migration dependencies from migration_lookup and sub_process plugins. * * @param array $process * A process configuration array. * * @return array * The migration dependencies. */