Issue #3043646 by tedbow, lauriii, bnjmnm, xjm, tim.plunkett, effulgentsia,...

Issue #3043646 by tedbow, lauriii, bnjmnm, xjm, tim.plunkett, effulgentsia, DyanneNova, webchick: For sites that have made layout overrides prior to 8.7.0 or sites that manually enable translation of the layout override field, add UI warnings

(cherry picked from commit a83655a4)

core/modules/content_translation/content_translation.admin.inc

@@ -255,6 +255,7 @@ function _content_translation_preprocess_language_content_settings_table(&$varia
             'class' => ['operations'],
           ],
         ],
+        '#field_name' => $field_name,
         'class' => ['field-settings'],
       ];
 

core/modules/layout_builder/css/layout-builder-content-translation.css

+/* @todo Move this to Seven as part of https://www.drupal.org/node/3041053 */
+.layout-builder-translation-warning {
+  background: left 2px url(../../../misc/icons/e29700/warning.svg) no-repeat;
+  padding-left: 20px;
+}

core/modules/layout_builder/layout_builder.libraries.yml

@@ -27,3 +27,9 @@ fourcol_section:
   css:
     theme:
       layouts/fourcol_section/fourcol_section.css: {}
+
+drupal.layout_builder_content_translation_admin:
+  version: VERSION
+  css:
+    theme:
+      css/layout-builder-content-translation.css: {}

core/modules/layout_builder/layout_builder.module

@@ -367,3 +367,46 @@ function layout_builder_entity_translation_create(EntityInterface $translation)
     $translation->set(OverridesSectionStorage::FIELD_NAME, []);
   }
 }
+
+/**
+ * Implements hook_theme_registry_alter().
+ */
+function layout_builder_theme_registry_alter(&$theme_registry) {
+  // Move our preprocess to run after
+  // content_translation_preprocess_language_content_settings_table().
+  if (!empty($theme_registry['language_content_settings_table']['preprocess functions'])) {
+    $preprocess_functions = &$theme_registry['language_content_settings_table']['preprocess functions'];
+    $index = array_search('layout_builder_preprocess_language_content_settings_table', $preprocess_functions);
+    if ($index !== FALSE) {
+      unset($preprocess_functions[$index]);
+      $preprocess_functions[] = 'layout_builder_preprocess_language_content_settings_table';
+    }
+  }
+}
+
+/**
+ * Implements hook_preprocess_HOOK() for language-content-settings-table.html.twig.
+ */
+function layout_builder_preprocess_language_content_settings_table(&$variables) {
+  foreach ($variables['build']['#rows'] as &$row) {
+    if (isset($row['#field_name']) && $row['#field_name'] === OverridesSectionStorage::FIELD_NAME) {
+      // Rebuild the label to include a warning about using translations with
+      // layouts.
+      $row['data'][1]['data']['field'] = [
+        'label' => $row['data'][1]['data']['field'],
+        'description' => [
+          '#type' => 'container',
+          '#markup' => t('<strong>Warning</strong>: Layout Builder does not support translating layouts. (<a href="https://www.drupal.org/docs/8/core/modules/layout-builder/layout-builder-and-content-translation">online documentation</a>)'),
+          '#attributes' => [
+            'class' => ['layout-builder-translation-warning'],
+          ],
+          '#attached' => [
+            'library' => [
+              'layout_builder/drupal.layout_builder_content_translation_admin',
+            ],
+          ],
+        ],
+      ];
+    }
+  }
+}