replicate_ui_event.patch

diff --git a/src/Form/ReplicateConfirmForm.php b/src/Form/ReplicateConfirmForm.php
index f8334a2dbd0..d0a4718324a 100644
--- a/src/Form/ReplicateConfirmForm.php
+++ b/src/Form/ReplicateConfirmForm.php
@@ -7,7 +7,9 @@
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Routing\RouteMatchInterface;
 use Drupal\Core\Url;
+use Drupal\replicate_ui\ReplicateUiOnlyUntranslatedEvent;
 use Symfony\Component\DependencyInjection\ContainerInterface;
+use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 
 class ReplicateConfirmForm extends ContentEntityConfirmFormBase {
 
@@ -21,11 +23,17 @@ class ReplicateConfirmForm extends ContentEntityConfirmFormBase {
    */
   protected $replicator;
 
+  /**
+   * @var \Symfony\Component\EventDispatcher\EventDispatcherInterface
+   */
+  protected EventDispatcherInterface $eventDispatcher;
+
   /**
    * {@inheritdoc}
    */
   public static function create(ContainerInterface $container) {
     $form = parent::create($container);
+    $form->eventDispatcher = $container->get('event_dispatcher');
     $form->replicator = $container->get('replicate.replicator');
     return $form;
   }
@@ -97,7 +105,9 @@ public function submitForm(array &$form, FormStateInterface $form_state) {
     $entity =  $this->routeMatch->getParameter($this->getEntityTypeId());;
     $label_key = $entity->getEntityType()->getKey('label');
     if ($entity instanceof TranslatableInterface) {
-      $only_untranslated = $form_state->getValue('only_untranslated');
+      if ($only_untranslated = $form_state->getValue('only_untranslated')) {
+        $this->eventDispatcher->dispatch(new ReplicateUiOnlyUntranslatedEvent($entity));
+      }
       foreach ($entity->getTranslationLanguages() as $translation_language) {
         $langcode = $translation_language->getId();
         $translation = $entity->getTranslation($langcode);
diff --git a/src/ReplicateUiOnlyUntranslatedEvent.php b/src/ReplicateUiOnlyUntranslatedEvent.php
new file mode 100644
index 00000000000..6a9c41bdd68
--- /dev/null
+++ b/src/ReplicateUiOnlyUntranslatedEvent.php
@@ -0,0 +1,18 @@
+<?php
+
+namespace Drupal\replicate_ui;
+
+use Drupal\Core\Entity\TranslatableInterface;
+use Symfony\Contracts\EventDispatcher\Event;
+
+
+final class ReplicateUiOnlyUntranslatedEvent extends Event {
+
+  public function __construct(protected TranslatableInterface $entity) {
+  }
+
+  public function getEntity(): TranslatableInterface {
+    return $this->entity;
+  }
+
+}

replicate_ui_only_untranslated.patch

diff --git a/src/Form/ReplicateConfirmForm.php b/src/Form/ReplicateConfirmForm.php
index 3b7069f58f..5fce6564ee 100644
--- a/src/Form/ReplicateConfirmForm.php
+++ b/src/Form/ReplicateConfirmForm.php
@@ -60,6 +60,13 @@ public function buildForm(array $form, FormStateInterface $form_state, RouteMatc
             ]),
           ];
         }
+
+        $args = ['@language' => $entity->getUntranslated()->language()->getName()];
+        $form['only_untranslated'] = [
+          '#type' => 'checkbox',
+          '#title' => $this->t('@language only', $args),
+          '#description' => $this->t('Replicate only the @language version of this entity', $args),
+        ];
       }
       else {
         $form['new_label'] = [
@@ -90,11 +97,14 @@ public function submitForm(array &$form, FormStateInterface $form_state) {
     $entity =  $this->routeMatch->getParameter($this->getEntityTypeId());;
     $label_key = $entity->getEntityType()->getKey('label');
     if ($entity instanceof TranslatableInterface) {
+      $only_untranslated = $form_state->getValue('only_untranslated');
       foreach ($entity->getTranslationLanguages() as $translation_language) {
         $langcode = $translation_language->getId();
-        if ($new_label = $form_state->getValue('new_label_' . $langcode)) {
-          /** @var \Drupal\Core\Entity\TranslatableInterface $translation */
-          $translation = $entity->getTranslation($langcode);
+        $translation = $entity->getTranslation($langcode);
+        if ($only_untranslated && !$translation->isDefaultTranslation()) {
+          $entity->removeTranslation($langcode);
+        }
+        elseif ($new_label = $form_state->getValue('new_label_' . $langcode)) {
           $translation->set($label_key, $new_label);
         }
       }

ReplicateFieldSubscriber.php

<?php

namespace Drupal\paragraphs\EventSubscriber;

use Drupal\Core\Entity\ContentEntityInterface;
use Drupal\Core\Field\FieldItemListInterface;
use Drupal\paragraphs\ParagraphInterface;
use Drupal\replicate\Events\ReplicateEntityFieldEvent;
use Drupal\replicate\Events\ReplicatorEvents;
use Drupal\replicate\Replicator;
use Drupal\replicate_ui\ReplicateUiOnlyUntranslatedEvent;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;

/**
 * Event subscriber that handles cloning through the Replicate module.
 */
class ReplicateFieldSubscriber implements EventSubscriberInterface {

  /**
   * The replicator service.
   *
   * @var \Drupal\replicate\Replicator
   */
  protected $replicator;

  protected \SplObjectStorage $onlyUnTranslated;

  /**
   * ReplicateFieldSubscriber constructor.
   *
   * @param \Drupal\replicate\Replicator $replicator
   *   The replicator service.
   */
  public function __construct(Replicator $replicator) {
    $this->replicator = $replicator;
    $this->onlyUnTranslated = new \SplObjectStorage();
  }

  /**
   * Replicates paragraphs when the parent entity is being replicated.
   *
   * @param \Drupal\replicate\Events\ReplicateEntityFieldEvent $event
   */
  public function onClone(ReplicateEntityFieldEvent $event) {
    foreach ($this->getParagraphReferencingFieldItems($event->getFieldItemList()) as $field_item) {
      // On the top, the children are pre-populated by
      // ::onReplicateUiOnlyUntranslatedEvent(), later only the parent entity
      // is.
      $only_untranslated = $this->onlyUnTranslated->contains($event->getEntity()) || $this->onlyUnTranslated->contains($field_item->entity);
      if ($only_untranslated) {
        $this->onlyUnTranslated->attach($field_item->entity);
      }
      $field_item->entity = $this->replicator->replicateEntity($field_item->entity);
      if ($only_untranslated) {
        foreach ($field_item->entity->getTranslationLanguages() as $translation_language) {
          $langcode = $translation_language->getId();
          $translation = $field_item->entity->getTranslation($langcode);
          if (!$translation->isDefaultTranslation()) {
            $field_item->entity->removeTranslation($langcode);
          }
        }
      }
    }
  }

  public function onReplicateUiOnlyUntranslatedEvent(ReplicateUiOnlyUntranslatedEvent $event) {
    $entity = $event->getEntity();
    // Pre-populate the store with paragraphs, onClone() does not get the
    // parent entity.
    if ($entity instanceof ContentEntityInterface) {
      foreach ($entity->getFields() as $field_item_list) {
        foreach ($this->getParagraphReferencingFieldItems($field_item_list) as $item) {
          $this->onlyUnTranslated->attach($item->entity);
        }
      }
    }
  }

  /**
   * @param \Drupal\Core\Field\FieldItemListInterface $field_item_list
   *
   * @return \Generator<\Drupal\Core\Field\FieldItemInterface>
   *   Every field item has a paragraph in $field_item->entity.
   */
  protected function getParagraphReferencingFieldItems(FieldItemListInterface $field_item_list): \Generator {
    if ($field_item_list->getItemDefinition()->getSetting('target_type') === 'paragraph') {
      foreach ($field_item_list as $field_item) {
        if ($field_item->entity instanceof ParagraphInterface) {
          yield $field_item;
        }
      }
    }
  }

  /**
   * {@inheritdoc}
   */
  public static function getSubscribedEvents() {
    $events[ReplicatorEvents::replicateEntityField('entity_reference_revisions')][] = 'onClone';
    $events['Drupal\replicate_ui\ReplicateUiOnlyUntranslatedEvent'][] = 'onReplicateUiOnlyUntranslatedEvent';
    return $events;
  }

}