Issue #2621122 by joekers, jonathan1055: Use ->value for $node->unpublish_on

    // Do not process the node if it has a publish_on time which is in the past,

    // as this implies that scheduled publishing has been blocked by one of the

    // API functions we provide. Hence unpublishing should be halted too.

    $publish_on = $node->publish_on;

    $publish_on = $node->publish_on->value;

    if (!empty($publish_on) && $publish_on <= REQUEST_TIME) {

      continue;

    }

    // Update timestamps.

    $old_change_date = $node->getChangedTime();

    $unpublish_on = $node->unpublish_on;

    $unpublish_on = $node->unpublish_on->value;

    $node->set('changed', $unpublish_on);

    $create_unpublishing_revision = $node->type->entity->getThirdPartySetting('scheduler', 'unpublish_revision', FALSE);

    }

    // Unset unpublish_on so the node will not get rescheduled by subsequent

    // calls to $node->save(). Save the value for use when calling Rules.

    $node->unpublish_on = NULL;

    $node->unpublish_on->value = NULL;

    // Invoke scheduler API to allow modules to alter the node before it is

    // saved.