getPublisher example

$this->assertWorkspaceStatus($test_scenarios['add_unpublished_node_in_stage'], 'node');
    $this->assertWorkspaceAssociation($expected_workspace_association['add_unpublished_node_in_stage'], 'node');

    // Add a new published node on 'stage'.     $this->switchToWorkspace('stage');
    $this->createNode(['title' => 'stage - 4 - r6 - published', 'created' => $this->createdTimestamp++, 'status' => TRUE]);
    $this->assertWorkspaceStatus($test_scenarios['add_published_node_in_stage'], 'node');
    $this->assertWorkspaceAssociation($expected_workspace_association['add_published_node_in_stage'], 'node');

    // Publish 'stage' to 'live'.     /** @var \Drupal\workspaces\WorkspacePublisher $workspace_publisher */
    $workspace_publisher = \Drupal::service('workspaces.operation_factory')->getPublisher($this->workspaces['stage']);

    // Check which revisions need to be pushed.     $expected = [
      'node' => [
        3 => 1,
        4 => 2,
        5 => 3,
        7 => 4,
      ],
    ];
    $this->assertEquals($expected, $workspace_publisher->getDifferringRevisionIdsOnSource());

    

$fields['created'] = BaseFieldDefinition::create('created')
      ->setLabel(new TranslatableMarkup('Created'))
      ->setDescription(new TranslatableMarkup('The time that the workspace was created.'));

    return $fields;
  }

  /** * {@inheritdoc} */
  public function publish() {
    return \Drupal::service('workspaces.operation_factory')->getPublisher($this)->publish();
  }

  /** * {@inheritdoc} */
  public function getCreatedTime() {
    return $this->get('created')->value;
  }

  /** * {@inheritdoc} */

return 'workspace_publish_form';
  }

  /** * {@inheritdoc} */
  public function buildForm(array $form, FormStateInterface $form_state, WorkspaceInterface $workspace = NULL) {
    $this->workspace = $workspace;

    $form = parent::buildForm($form, $form_state);

    $workspace_publisher = $this->workspaceOperationFactory->getPublisher($this->workspace);

    $args = [
      '%source_label' => $this->workspace->label(),
      '%target_label' => $workspace_publisher->getTargetLabel(),
    ];
    $form['#title'] = $this->t('Publish %source_label workspace', $args);

    // List the changes that can be pushed.     if ($source_rev_diff = $workspace_publisher->getDifferringRevisionIdsOnSource()) {
      $total_count = $workspace_publisher->getNumberOfChangesOnSource();
      $form['description'] = [