Embed paragraphs cannot be translated

@matthieuscarset this is possible, if the paragraph type is correctly configured - see https://www.drupal.org/docs/contributed-modules/paragraphs/multilingual-... →

I have found a problem more recently, where the translation gets created correctly when using this combination of paragraphs, paragraphs_inline_entity_form, entity_embed and embed, but any subsequent edits lead to an ajax error:

Symfony\Component\Routing\Exception\RouteNotFoundException: Route "entity.paragraph.content_translation_delete" does not exist. in Drupal\Core\Routing\RouteProvider->getRouteByName() (line 211 of core/lib/Drupal/Core/Routing/RouteProvider.php).
Drupal\Core\Routing\UrlGenerator->getRoute('entity.paragraph.content_translation_delete') (Line: 276)
Drupal\Core\Routing\UrlGenerator->generateFromRoute('entity.paragraph.content_translation_delete', Array, Array, 1) (Line: 108)
Drupal\Core\Render\MetadataBubblingUrlGenerator->generateFromRoute('entity.paragraph.content_translation_delete', Array, Array, 1) (Line: 765)
Drupal\Core\Url->toString(1) (Line: 183)
Drupal\Core\Utility\LinkGenerator->generate(Object, Object) (Line: 102)
Drupal\Core\Render\Element\Link::preRenderLink(Array)
call_user_func_array(Array, Array) (Line: 113)
Drupal\Core\Render\Renderer->doTrustedCallback(Array, Array, 'Render #pre_render callbacks must be methods of a class that implements \Drupal\Core\Security\TrustedCallbackInterface or be an anonymous function. The callback was %s. See https://www.drupal.org/node/2966725 → ', 'exception', 'Drupal\Core\Render\Element\RenderCallbackInterface') (Line: 875)
Drupal\Core\Render\Renderer->doCallback('#pre_render', Array, Array) (Line: 432)
Drupal\Core\Render\Renderer->doRender(Array) (Line: 504)
Drupal\Core\Render\Renderer->doRender(Array) (Line: 504)
Drupal\Core\Render\Renderer->doRender(Array, 1) (Line: 248)
Drupal\Core\Render\Renderer->render(Array, 1) (Line: 153)
Drupal\Core\Render\Renderer->Drupal\Core\Render\{closure}() (Line: 638)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 152)
Drupal\Core\Render\Renderer->renderRoot(Array) (Line: 36)
Drupal\Core\Ajax\OpenDialogCommand->getRenderedContent() (Line: 148)
Drupal\Core\Ajax\OpenDialogCommand->render() (Line: 43)
Drupal\Core\Ajax\AjaxResponse->addCommand(Object) (Line: 109)
Drupal\entity_browser\Controllers\EntityBrowserController->entityBrowserEdit(Object, 'default', Object)
call_user_func_array(Array, Array) (Line: 123)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 638)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 121)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array) (Line: 97)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 181)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 76)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 53)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 28)
Drupal\Core\StackMiddleware\ContentLength->handle(Object, 1, 1) (Line: 53)
Asm89\Stack\Cors->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 36)
Drupal\Core\StackMiddleware\AjaxPageState->handle(Object, 1, 1) (Line: 51)
Drupal\Core\StackMiddleware\StackedHttpKernel->handle(Object, 1, 1) (Line: 741)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)

This is a workaround, since there is no route in the patch in #2721665-69: Problems with multilingual entities → to delete a paragraph translation; it's only supported in the parent entity. The easiest fix is to remove the "Delete translation" button. Not ideal, it would be better to handle the translation routes or add the link templates in the paragraph module so the ContentTranslationRouteSubscriber can add the routes.

/**
 * Implements hook_form_BASE_FORM_ID_alter().
 */
function MY_MODULE_form_paragraph_form_alter(&$form, \Drupal\Core\Form\FormStateInterface $form_state, $form_id) {
  if (!$form_state->getFormObject() instanceof \Drupal\Core\Entity\EntityFormInterface) {
    return;
  }
  $entity = $form_state->getFormObject()->getEntity();
  if (!$entity || !$entity->isTranslatable()) {
    return;
  }
  $form['actions']['#after_build'][] = '_MY_MODULE_paragraph_translatable_form_after_build';
}

/* Callback for #after_build to remove delete translation link using missing Route */
function _MY_MODULE_paragraph_translatable_form_after_build($element, FormStateInterface $form_state) {
  if (isset($element['delete_translation'])
      && $element['delete_translation']['#url']->getRouteName() == 'entity.paragraph.content_translation_delete') {
    unset($element['delete_translation']);
  }
  return $element;
}