draft_translation_helper.module

<?php

/**
 * @file
 * Contains draft_translation_helper.module.
 */

use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\Core\Form\FormStateInterface;
/**
 * Implements hook_help().
 */
function draft_translation_helper_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    // Main module help for the draft_translation_helper module.
    case 'help.page.draft_translation_helper':
      $output = '';
      $output .= '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('Prevents users from translating content with an active draft') . '</p>';
      return $output;

    default:
  }
}

function draft_translation_helper_default_translation_is_draft($front = false) {
  $return =  &drupal_static(__FUNCTION__);

  if(is_null($return)){
    $return = false;
    $node = \Drupal::request()->attributes->get('node');

    if(!empty($node) && !$node->isDefaultTranslation()){
      // Determining if the original node has a draft in progress is determined differently in display vs. edit form.
      $draft_in_progress = $front ? !$node->getUntranslated()->isLatestRevision() : !$node->getUntranslated()->isDefaultRevision();
      $account = Drupal::currentUser();
      $can_edit = $node->access('update', $account);
      if ( $can_edit && $draft_in_progress ){
        $language = $node->getUntranslated()->language();
        $return = $language->getName();
      }
    }
  }
  return $return;
}

function draft_translation_helper_preprocess_block(&$variables) {
  if ($variables['plugin_id'] == 'local_tasks_block') {
    /*
     * If the node is a translation, and the original node has a draft in
     * progress, make the node edit buttons inactive and let the user know
     * they will be back once the original node's draft is published or removed.
     */
    if ($language = draft_translation_helper_default_translation_is_draft(TRUE)) {
      $node = \Drupal::request()->attributes->get('node');
      $message = t('There is a draft in progress for the @language version of this page. 
      Editing options are disabled until the @language draft is published or removed. 
      The @language draft-in-progress can be found <a href="/node/@id/latest">here</a>',
        ['@language' => $language, '@id' => $node->id()]);
      $variables['attributes']['class'][] = 'local-actions-unavailable';
      $variables['#attached']['library'][] = 'draft_translation_helper/draft_translation_helper_fe';
      $variables['content']['#primary']['other'] = [
        '#markup' => sprintf('<div data-alert="" class="alert-box radius alert">%s</div>', $message),
        '#allowed_tags' => ['div', 'a'],
        '#weight' => -50,
      ];
    }
  }
}

/**
 * Implements hook_form_BASE_FORM_ID_alter().
 */
function draft_translation_helper_form_node_form_alter(&$form, FormStateInterface $form_state, $form_id) {
  /*
   * If the node is a translation, and the original node has a draft in progress,
   * hide the form and inform the user they should not make edits until the
   * original node's draft is published or removed
   */
  if ($language = draft_translation_helper_default_translation_is_draft()) {
    $node = \Drupal::request()->attributes->get('node');
    $message = t('There is a draft in progress for the @language version of this page. 
      Editing options are disabled until the @language draft is published or removed. 
      The @language draft-in-progress can be found <a href="/node/@id/latest">here</a>',
      ['@language' => $language, '@id' => $node->id()]);
    drupal_set_message($message, 'error');
    $form['#attributes']['class'][] = 'hidden';
  }
}