getNumberOfChangesOnSource example

// Check that there is no content in Dev that's not also in Local 1.     $this->assertEmpty($workspace_merger->getDifferringRevisionIdsOnTarget());
    $this->assertEquals(0, $workspace_merger->getNumberOfChangesOnTarget());

    // Check that there is only one node in Local 1 that's not available in Dev,     // revision 7 created above for the fourth test article.     $expected = [
      'node' => [7 => 4],
    ];
    $this->assertEquals($expected, $workspace_merger->getDifferringRevisionIdsOnSource());
    $this->assertEquals(1, $workspace_merger->getNumberOfChangesOnSource());

    // Merge the contents of Local 1 into Dev, and check that Dev, Local 1 and     // Local 2 have the same content.     $workspace_merger->merge();

    $this->assertEmpty($workspace_merger->getDifferringRevisionIdsOnTarget());
    $this->assertEquals(0, $workspace_merger->getNumberOfChangesOnTarget());
    $this->assertEmpty($workspace_merger->getDifferringRevisionIdsOnSource());
    $this->assertEquals(0, $workspace_merger->getNumberOfChangesOnSource());

    $this->switchToWorkspace('dev');
    

$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'] = [
        '#theme' => 'item_list',
        '#title' => $this->formatPlural($total_count, 'There is @count item that can be published from %source_label to %target_label', 'There are @count items that can be published from %source_label to %target_label', $args),
        '#items' => [],
        '#total_count' => $total_count,
      ];
      foreach ($source_rev_diff as $entity_type_id => $revision_difference) {
        $form['description']['#items'][$entity_type_id] = $this->entityTypeManager->getDefinition($entity_type_id)->getCountLabel(count($revision_difference));
      }

      $form['actions']['submit']['#value'] = $this->formatPlural($total_count, 'Publish @count item to @target', 'Publish @count items to @target', ['@target' => $workspace_publisher->getTargetLabel()]);
    }

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

    $workspace_merger = $this->workspaceOperationFactory->getMerger($this->sourceWorkspace, $this->targetWorkspace);

    $args = [
      '%source_label' => $this->sourceWorkspace->label(),
      '%target_label' => $this->targetWorkspace->label(),
    ];

    // List the changes that can be merged into the target.     if ($source_rev_diff = $workspace_merger->getDifferringRevisionIdsOnSource()) {
      $total_count = $workspace_merger->getNumberOfChangesOnSource();
      $form['merge'] = [
        '#theme' => 'item_list',
        '#title' => $this->formatPlural($total_count, 'There is @count item that can be merged from %source_label to %target_label', 'There are @count items that can be merged from %source_label to %target_label', $args),
        '#items' => [],
        '#total_count' => $total_count,
      ];
      foreach ($source_rev_diff as $entity_type_id => $revision_difference) {
        $form['merge']['#items'][$entity_type_id] = $this->entityTypeManager->getDefinition($entity_type_id)->getCountLabel(count($revision_difference));
      }
    }