Issue #2230637 by plach, fran seva, yched, swentel: Create a Language field...

Issue #2230637 by plach, fran seva, yched, swentel: Create a Language field widget and the related formatter

core/lib/Drupal/Core/Entity/ContentEntityForm.php

@@ -51,6 +51,8 @@ public static function create(ContainerInterface $container) {
   public function form(array $form, FormStateInterface $form_state) {
     $form = parent::form($form, $form_state);
     $this->getFormDisplay($form_state)->buildForm($this->entity, $form, $form_state);
+    // Allow modules to act before and after form language is updated.
+    $form['#entity_builders']['update_form_langcode'] = [$this, 'updateFormLangcode'];
     return $form;
   }
 
@@ -58,7 +60,6 @@ public function form(array $form, FormStateInterface $form_state) {
    * {@inheritdoc}
    */
   public function validate(array $form, FormStateInterface $form_state) {
-    $this->updateFormLangcode($form_state);
     $entity = $this->buildEntity($form, $form_state);
     $this->getFormDisplay($form_state)->validateFormValues($entity, $form, $form_state);
 
@@ -69,11 +70,15 @@ public function validate(array $form, FormStateInterface $form_state) {
   }
 
   /**
-   * Initialize the form state and the entity before the first form build.
+   * Initializes the form state and the entity before the first form build.
+   *
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   The current state of the form.
    */
   protected function init(FormStateInterface $form_state) {
     // Ensure we act on the translation object corresponding to the current form
     // language.
+    $this->initFormLangcodes($form_state);
     $langcode = $this->getFormLangcode($form_state);
     $this->entity = $this->entity->getTranslation($langcode);
 
@@ -84,15 +89,33 @@ protected function init(FormStateInterface $form_state) {
   }
 
   /**
-   * {@inheritdoc}
+   * Initializes form language code values.
+   *
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   The current state of the form.
    */
-  public function getFormLangcode(FormStateInterface $form_state) {
+  protected function initFormLangcodes(FormStateInterface $form_state) {
+    // Store the entity default language to allow checking whether the form is
+    // dealing with the original entity or a translation.
+    if (!$form_state->has('entity_default_langcode')) {
+      $form_state->set('entity_default_langcode', $this->entity->getUntranslated()->language()->getId());
+    }
+    // This value might have been explicitly populated to work with a particular
+    // entity translation. If not we fall back to the most proper language based
+    // on contextual information.
     if (!$form_state->has('langcode')) {
       // Imply a 'view' operation to ensure users edit entities in the same
       // language they are displayed. This allows to keep contextual editing
       // working also for multilingual entities.
       $form_state->set('langcode', $this->entityManager->getTranslationFromContext($this->entity)->language()->getId());
     }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormLangcode(FormStateInterface $form_state) {
+    $this->initFormLangcodes($form_state);
     return $form_state->get('langcode');
   }
 
@@ -100,7 +123,8 @@ public function getFormLangcode(FormStateInterface $form_state) {
    * {@inheritdoc}
    */
   public function isDefaultFormLangcode(FormStateInterface $form_state) {
-    return $this->getFormLangcode($form_state) == $this->entity->getUntranslated()->language()->getId();
+    $this->initFormLangcodes($form_state);
+    return $form_state->get('langcode') == $form_state->get('entity_default_langcode');
   }
 
   /**
@@ -138,13 +162,26 @@ public function setFormDisplay(EntityFormDisplayInterface $form_display, FormSta
   /**
    * Updates the form language to reflect any change to the entity language.
    *
+   * There are use cases for modules to act both before and after form language
+   * being updated, thus the update is performed through an entity builder
+   * callback, which allows to support both cases.
+   *
+   * @param string $entity_type_id
+   *   The entity type identifier.
+   * @param \Drupal\Core\Entity\EntityInterface $entity
+   *   The entity updated with the submitted values.
+   * @param array $form
+   *   The complete form array.
    * @param \Drupal\Core\Form\FormStateInterface $form_state
    *   The current state of the form.
+   *
+   * @see \Drupal\Core\Entity\ContentEntityForm::form()
    */
-  protected function updateFormLangcode(FormStateInterface $form_state) {
+  public function updateFormLangcode($entity_type_id, EntityInterface $entity, array $form, FormStateInterface $form_state) {
     // Update the form language as it might have changed.
-    if ($form_state->hasValue('langcode') && $this->isDefaultFormLangcode($form_state)) {
-      $form_state->set('langcode', $form_state->getValue('langcode'));
+    if ($this->isDefaultFormLangcode($form_state)) {
+      $langcode = $entity->language()->getId();
+      $form_state->set('langcode', $langcode);
     }
   }
 

core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/LanguageFormatter.php

+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Field\Plugin\Field\FieldFormatter\LanguageFormatter.
+ */
+
+namespace Drupal\Core\Field\Plugin\Field\FieldFormatter;
+
+use Drupal\Component\Utility\String;
+use Drupal\Core\Field\FormatterBase;
+use Drupal\Core\Field\FieldItemListInterface;
+
+/**
+ * Plugin implementation of the 'language' formatter.
+ *
+ * @FieldFormatter(
+ *   id = "language",
+ *   label = @Translation("Language"),
+ *   field_types = {
+ *     "language"
+ *   }
+ * )
+ */
+class LanguageFormatter extends FormatterBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function viewElements(FieldItemListInterface $items) {
+    $elements = array();
+
+    foreach ($items as $delta => $item) {
+      $elements[$delta] = array('#markup' => $item->language ? String::checkPlain($item->language->getName()) : '');
+    }
+
+    return $elements;
+  }
+
+}

core/lib/Drupal/Core/Field/Plugin/Field/FieldType/LanguageItem.php

@@ -20,6 +20,8 @@
  *   id = "language",
  *   label = @Translation("Language"),
  *   description = @Translation("An entity field referencing a language."),
+ *   default_widget = "language_select",
+ *   default_formatter = "language",
  *   no_ui = TRUE,
  *   constraints = {
  *     "ComplexData" = {

core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/LanguageSelectWidget.php

+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Field\Plugin\Field\FieldWidget\LanguageSelectWidget.
+ */
+
+namespace Drupal\Core\Field\Plugin\Field\FieldWidget;
+
+use Drupal\Core\Field\FieldItemListInterface;
+use Drupal\Core\Field\WidgetBase;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Language\LanguageInterface;
+
+/**
+ * Plugin implementation of the 'Language' widget.
+ *
+ * @FieldWidget(
+ *   id = "language_select",
+ *   label = @Translation("Language select"),
+ *   field_types = {
+ *     "language"
+ *   }
+ * )
+ */
+class LanguageSelectWidget extends WidgetBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function formElement(FieldItemListInterface $items, $delta, array $element, array &$form, FormStateInterface $form_state) {
+    $element['value'] = $element + array(
+      '#type' => 'language_select',
+      '#default_value' => $items[$delta]->value,
+      '#languages' => LanguageInterface::STATE_ALL,
+    );
+
+    return $element;
+  }
+
+}

core/modules/aggregator/src/Entity/Feed.php

@@ -153,7 +153,14 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
 
     $fields['langcode'] = BaseFieldDefinition::create('language')
       ->setLabel(t('Language code'))
-      ->setDescription(t('The feed language code.'));
+      ->setDescription(t('The feed language code.'))
+      ->setDisplayOptions('view', array(
+        'type' => 'hidden',
+      ))
+      ->setDisplayOptions('form', array(
+        'type' => 'language_select',
+        'weight' => 2,
+      ));
 
     $fields['url'] = BaseFieldDefinition::create('uri')
       ->setLabel(t('URL'))

core/modules/aggregator/src/FeedForm.php

@@ -7,13 +7,9 @@
 
 namespace Drupal\aggregator;
 
-use Drupal\Component\Utility\String;
 use Drupal\Core\Entity\ContentEntityForm;
-use Drupal\Core\Entity\EntityManagerInterface;
 use Drupal\Core\Form\FormStateInterface;
-use Drupal\Core\Language\LanguageInterface;
 use Drupal\Core\Url;
-use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
  * Form controller for the aggregator feed edit forms.
@@ -24,21 +20,13 @@ class FeedForm extends ContentEntityForm {
    * {@inheritdoc}
    */
   public function form(array $form, FormStateInterface $form_state) {
-    $feed = $this->entity;
-
-    // @todo: convert to a language selection widget defined in the base field.
-    //   Blocked on https://drupal.org/node/2226493 which adds a generic
-    //   language widget.
-    // Language module may expose or hide this element, see language_form_alter().
-    $form['langcode'] = array(
-      '#title' => $this->t('Language'),
-      '#type' => 'language_select',
-      '#default_value' => $feed->language()->getId(),
-      '#languages' => LanguageInterface::STATE_ALL,
-      '#weight' => -4,
-    );
+    $form = parent::form($form, $form_state);
+    // @todo Allow non translatable entity types having language support to be
+    // configured in the content language setting.
 
-    return parent::form($form, $form_state, $feed);
+    // Ensure the language widget is displayed.
+    $form['langcode']['#access'] = TRUE;
+    return $form;
   }
 
   /**

core/modules/aggregator/src/Tests/FeedLanguageTest.php

@@ -52,8 +52,8 @@ public function testFeedLanguage() {
     /** @var \Drupal\aggregator\FeedInterface[] $feeds */
     $feeds = array();
     // Create feeds.
-    $feeds[1] = $this->createFeed(NULL, array('langcode' => $this->langcodes[1]));
-    $feeds[2] = $this->createFeed(NULL, array('langcode' => $this->langcodes[2]));
+    $feeds[1] = $this->createFeed(NULL, array('langcode[0][value]' => $this->langcodes[1]));
+    $feeds[2] = $this->createFeed(NULL, array('langcode[0][value]' => $this->langcodes[2]));
 
     // Make sure that the language has been assigned.
     $this->assertEqual($feeds[1]->language()->getId(), $this->langcodes[1]);

core/modules/block_content/src/BlockContentForm.php

@@ -12,9 +12,7 @@
 use Drupal\Core\Entity\EntityManagerInterface;
 use Drupal\Core\Entity\EntityStorageInterface;
 use Drupal\Core\Form\FormStateInterface;
-use Drupal\Core\Language\LanguageInterface;
 use Drupal\Core\Language\LanguageManagerInterface;
-use Drupal\language\Entity\ContentLanguageSettings;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
@@ -105,15 +103,6 @@ public function form(array $form, FormStateInterface $form_state) {
     // names.
     $form['#attributes']['class'][0] = 'block-' . Html::getClass($block->bundle()) . '-form';
 
-    $form['langcode'] = array(
-      '#title' => $this->t('Language'),
-      '#type' => 'language_select',
-      '#default_value' => $block->getUntranslated()->language()->getId(),
-      '#languages' => LanguageInterface::STATE_ALL,
-      // Language module may expose or hide this element, see language_form_alter().
-      '#access' => FALSE,
-    );
-
     $form['advanced'] = array(
       '#type' => 'vertical_tabs',
       '#weight' => 99,

core/modules/block_content/src/Entity/BlockContent.php

@@ -156,9 +156,16 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
       ->setSetting('unsigned', TRUE);
 
     $fields['langcode'] = BaseFieldDefinition::create('language')
-      ->setLabel(t('Language code'))
+      ->setLabel(t('Language'))
       ->setDescription(t('The custom block language code.'))
-      ->setRevisionable(TRUE);
+      ->setRevisionable(TRUE)
+      ->setDisplayOptions('view', array(
+        'type' => 'hidden',
+      ))
+      ->setDisplayOptions('form', array(
+        'type' => 'language_select',
+        'weight' => 2,
+      ));
 
     $fields['info'] = BaseFieldDefinition::create('string')
       ->setLabel(t('Block description'))

core/modules/comment/src/CommentForm.php

@@ -14,10 +14,8 @@
 use Drupal\Core\Entity\ContentEntityForm;
 use Drupal\Core\Entity\EntityManagerInterface;
 use Drupal\Core\Form\FormStateInterface;
-use Drupal\Core\Language\Language;
 use Drupal\Core\Language\LanguageInterface;
 use Drupal\Core\Session\AccountInterface;
-use Drupal\language\Entity\ContentLanguageSettings;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
@@ -162,15 +160,6 @@ public function form(array $form, FormStateInterface $form_state) {
       $form['author']['name']['#attributes']['data-drupal-default-value'] = $this->config('user.settings')->get('anonymous');
     }
 
-    $form['langcode'] = array(
-      '#title' => t('Language'),
-      '#type' => 'language_select',
-      '#default_value' => $comment->getUntranslated()->language()->getId(),
-      '#languages' => Language::STATE_ALL,
-      // Language module may expose or hide this element, see language_form_alter().
-      '#access' => FALSE,
-    );
-
     // Add author email and homepage fields depending on the current user.
     $form['author']['mail'] = array(
       '#type' => 'email',

core/modules/comment/src/Entity/Comment.php

@@ -221,8 +221,15 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
       ->setRequired(TRUE);
 
     $fields['langcode'] = BaseFieldDefinition::create('language')
-      ->setLabel(t('Language code'))
-      ->setDescription(t('The comment language code.'));
+      ->setLabel(t('Language'))
+      ->setDescription(t('The comment language code.'))
+      ->setDisplayOptions('view', array(
+        'type' => 'hidden',
+      ))
+      ->setDisplayOptions('form', array(
+        'type' => 'language_select',
+        'weight' => 2,
+      ));
 
     $fields['subject'] = BaseFieldDefinition::create('string')
       ->setLabel(t('Subject'))

core/modules/comment/src/Tests/CommentLanguageTest.php

@@ -93,7 +93,7 @@ function testCommentLanguage() {
       $edit = array(
         'title[0][value]' => $title,
         'body[0][value]' => $this->randomMachineName(),
-        'langcode' => $node_langcode,
+        'langcode[0][value]' => $node_langcode,
         'comment[0][status]' => CommentItemInterface::OPEN,
       );
       $this->drupalPostForm("node/add/article", $edit, t('Save'));

core/modules/contact/src/Entity/Message.php

@@ -144,8 +144,12 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
       ->setReadOnly(TRUE);
 
     $fields['langcode'] = BaseFieldDefinition::create('language')
-      ->setLabel(t('Language code'))
-      ->setDescription(t('The comment language code.'));
+      ->setLabel(t('Language'))
+      ->setDescription(t('The message language code.'))
+      ->setDisplayOptions('form', array(
+        'type' => 'language_select',
+        'weight' => 2,
+      ));
 
     $fields['name'] = BaseFieldDefinition::create('string')
       ->setLabel(t("The sender's name"))

core/modules/contact/src/MessageForm.php

@@ -12,7 +12,6 @@
 use Drupal\Core\Entity\EntityManagerInterface;
 use Drupal\Core\Flood\FloodInterface;
 use Drupal\Core\Form\FormStateInterface;
-use Drupal\Core\Language\Language;
 use Drupal\Core\Language\LanguageInterface;
 use Drupal\Core\Language\LanguageManagerInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
@@ -98,15 +97,6 @@ public function form(array $form, FormStateInterface $form_state) {
       $form['preview']['message'] = $this->entityManager->getViewBuilder('contact_message')->view($message, 'full');
     }
 
-    $form['langcode'] = array(
-      '#title' => $this->t('Language'),
-      '#type' => 'language_select',
-      '#default_value' => $message->getUntranslated()->language()->getId(),
-      '#languages' => Language::STATE_ALL,
-      // Language module may expose or hide this element, see language_form_alter().
-      '#access' => FALSE,
-    );
-
     $form['name'] = array(
       '#type' => 'textfield',
       '#title' => $this->t('Your name'),

core/modules/content_translation/content_translation.module

@@ -291,9 +291,10 @@ function content_translation_form_alter(array &$form, FormStateInterface $form_s
     // Handle fields shared between translations when there is at least one
     // translation available or a new one is being created.
     if (!$entity->isNew() && (!isset($translations[$form_langcode]) || count($translations) > 1)) {
-      foreach ($entity->getFieldDefinitions() as $property_name => $definition) {
-        if (isset($form[$property_name])) {
-          $form[$property_name]['#multilingual'] = $definition->isTranslatable();
+      $langcode_key = $entity->getEntityType()->getKey('langcode') ?: 'langcode';
+      foreach ($entity->getFieldDefinitions() as $field_name => $definition) {
+        if (isset($form[$field_name]) && $field_name != $langcode_key) {
+          $form[$field_name]['#multilingual'] = $definition->isTranslatable();
         }
       }
     }

core/modules/content_translation/src/ContentTranslationHandler.php

@@ -144,22 +144,33 @@ public function entityFormAlter(array &$form, FormStateInterface $form_state, En
       }
     }
 
-    // Disable languages for existing translations, so it is not possible to
-    // switch this node to some language which is already in the translation
-    // set.
-    $language_widget = isset($form['langcode']) && $form['langcode']['#type'] == 'language_select';
-    if ($language_widget && $has_translations) {
-      $form['langcode']['#options'] = array();
-      foreach (language_list(LanguageInterface::STATE_CONFIGURABLE) as $language) {
-        if (empty($translations[$language->getId()]) || $language->getId() == $entity_langcode) {
-          $form['langcode']['#options'][$language->getId()] = $language->getName();
+    // Locate the language widget.
+    $language_field = $this->entityType->getKey('langcode') ?: 'langcode';
+    if (isset($form[$language_field])) {
+      $language_widget = &$form[$language_field];
+    }
+
+    // If we are editing the source entity, limit the list of languages so that
+    // it is not possible to switch to a language for which a translation
+    // already exists. Note that this will only work if the widget is structured
+    // like \Drupal\Core\Field\Plugin\Field\FieldWidget\LanguageSelectWidget.
+    if (isset($language_widget['widget'][0]['value']) && !$is_translation && $has_translations) {
+      $language_select = &$language_widget['widget'][0]['value'];
+      if ($language_select['#type'] == 'language_select') {
+        $options = array();
+        foreach (\Drupal::languageManager()->getLanguages() as $language) {
+          // Show the current language, and the languages for which no
+          // translation already exists.
+          if (empty($translations[$language->getId()]) || $language->getId() == $entity_langcode) {
+            $options[$language->getId()] = $language->getName();
+          }
         }
+        $language_select['#options'] = $options;
       }
     }
-
     if ($is_translation) {
-      if ($language_widget) {
-        $form['langcode']['#access'] = FALSE;
+      if (isset($language_widget)) {
+        $language_widget['widget']['#access'] = FALSE;
       }
 
       // Replace the delete button with the delete translation one.
@@ -271,8 +282,8 @@ public function entityFormAlter(array &$form, FormStateInterface $form_state, En
         '#default_value' => $new_translation ? '' : format_date($date, 'custom', 'Y-m-d H:i:s O'),
       );
 
-      if ($language_widget) {
-        $form['langcode']['#multilingual'] = TRUE;
+      if (isset($language_widget)) {
+        $language_widget['#multilingual'] = TRUE;
       }
 
       $form['#process'][] = array($this, 'entityFormSharedElements');

core/modules/content_translation/src/Tests/ContentTranslationUITest.php

@@ -8,7 +8,6 @@
 namespace Drupal\content_translation\Tests;
 
 use Drupal\Core\Entity\EntityInterface;
-use Drupal\Core\Entity\ContentEntityBase;
 use Drupal\Core\Language\Language;
 use Drupal\Core\Language\LanguageInterface;
 
@@ -74,7 +73,7 @@ protected function doTestBasicTranslation() {
     $path = $langcode . '/' . $content_translation_path . '/add/' . $default_langcode . '/' . $langcode;
     $this->drupalPostForm($path, $this->getEditValues($values, $langcode), $this->getFormSubmitActionForNewTranslation($entity, $langcode));
     if ($this->testLanguageSelector) {
-      $this->assertNoFieldByXPath('//select[@id="edit-langcode"]', NULL, 'Language selector correctly disabled on translations.');
+      $this->assertNoFieldByXPath('//select[@id="edit-langcode-0-value"]', NULL, 'Language selector correctly disabled on translations.');
     }
     $entity = entity_load($this->entityTypeId, $this->entityId, TRUE);
     $this->drupalGet($entity->getSystemPath('drupal:content-translation-overview'));
@@ -137,20 +136,19 @@ protected function doTestTranslationOverview() {
   protected function doTestOutdatedStatus() {
     $entity = entity_load($this->entityTypeId, $this->entityId, TRUE);
     $langcode = 'fr';
-    $default_langcode = $this->langcodes[0];
+    $languages = \Drupal::languageManager()->getLanguages();
 
     // Mark translations as outdated.
     $edit = array('content_translation[retranslate]' => TRUE);
-    $edit_path = $entity->getSystemPath('edit-form');
-    $this->drupalPostForm($langcode . '/' . $edit_path, $edit, $this->getFormSubmitAction($entity, $langcode));
+    $path = $entity->getSystemPath('edit-form');
+    $this->drupalPostForm($path, $edit, $this->getFormSubmitAction($entity, $langcode), array('language' => $languages[$langcode]));
     $entity = entity_load($this->entityTypeId, $this->entityId, TRUE);
 
     // Check that every translation has the correct "outdated" status, and that
     // the Translation fieldset is open if the translation is "outdated".
     foreach ($this->langcodes as $added_langcode) {
-      $prefix = $added_langcode != $default_langcode ? $added_langcode . '/' : '';
-      $path = $prefix . $edit_path;
-      $this->drupalGet($path);
+      $options = array('language' => $languages[$added_langcode]);
+      $this->drupalGet($path, $options);
       if ($added_langcode == $langcode) {
         $this->assertFieldByXPath('//input[@name="content_translation[retranslate]"]', FALSE, 'The retranslate flag is not checked by default.');
         $this->assertFalse($this->xpath('//details[@id="edit-content-translation" and @open="open"]'), 'The translation tab should be collapsed by default.');
@@ -159,8 +157,8 @@ protected function doTestOutdatedStatus() {
         $this->assertFieldByXPath('//input[@name="content_translation[outdated]"]', TRUE, 'The translate flag is checked by default.');
         $this->assertTrue($this->xpath('//details[@id="edit-content-translation" and @open="open"]'), 'The translation tab is correctly expanded when the translation is outdated.');
         $edit = array('content_translation[outdated]' => FALSE);
-        $this->drupalPostForm($path, $edit, $this->getFormSubmitAction($entity, $added_langcode));
-        $this->drupalGet($path);
+        $this->drupalPostForm($path, $edit, $this->getFormSubmitAction($entity, $added_langcode), $options);
+        $this->drupalGet($path, $options);
         $this->assertFieldByXPath('//input[@name="content_translation[retranslate]"]', FALSE, 'The retranslate flag is now shown.');
         $entity = entity_load($this->entityTypeId, $this->entityId, TRUE);
         $this->assertFalse($entity->translation[$added_langcode]['outdated'], 'The "outdated" status has been correctly stored.');

core/modules/language/language.module

@@ -5,12 +5,15 @@
  * Add language handling functionality to Drupal.
  */
 
-use Drupal\Component\Utility\String;
+use Drupal\Core\Access\AccessResult;
 use Drupal\Core\Entity\ContentEntityFormInterface;
 use Drupal\Core\Entity\EntityFormInterface;
+use Drupal\Core\Field\FieldDefinitionInterface;
+use Drupal\Core\Field\FieldItemListInterface;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Language\LanguageInterface;
 use Drupal\Core\Routing\RouteMatchInterface;
+use Drupal\Core\Session\AccountInterface;
 use Drupal\language\ConfigurableLanguageInterface;
 use Drupal\language\Entity\ContentLanguageSettings;
 use Drupal\language\Plugin\LanguageNegotiation\LanguageNegotiationUI;
@@ -173,6 +176,24 @@ function language_process_language_select($element) {
   return $element;
 }
 
+/**
+ * Implements hook_entity_base_field_info_alter().
+ */
+function language_entity_base_field_info_alter(&$fields) {
+  foreach ($fields as $definition) {
+    // Set configurable form display for language fields with display options.
+    if ($definition->getType() == 'language') {
+      foreach (array('form', 'view') as $type)  {
+        if ($definition->getDisplayOptions($type)) {
+          // The related configurations will be purged manually on Language
+          // module uninstallation. @see language_modules_uninstalled().
+          $definition->setDisplayConfigurable($type, TRUE);
+        }
+      }
+    }
+  }
+}
+
 /**
  * Submit handler for the forms that have a language_configuration element.
  */
@@ -348,6 +369,19 @@ function language_modules_installed($modules) {
     $negotiator->updateConfiguration(array());
     $negotiator->purgeConfiguration();
   }
+  else {
+    // In language_entity_base_field_info_alter() we are altering view/form
+    // display definitions to make language fields display configurable. Since
+    // this is not a hard dependency, and thus is not detected by the config
+    // system, we have to clean up the related values manually.
+    foreach (array('entity_view_display', 'entity_form_display') as $key) {
+      $displays = \Drupal::entityManager()->getStorage($key)->loadMultiple();
+      /** @var \Drupal\Core\Entity\Display\EntityDisplayInterface $display */
+      foreach ($displays as $display) {
+        $display->save();
+      }
+    }
+  }
 }
 
 /**
@@ -481,3 +515,16 @@ function language_field_info_alter(&$info) {
   // Change the default behavior of language field.
   $info['language']['class'] = '\Drupal\language\DefaultLanguageItem';
 }
+
+/**