Issue #2489560 by Manjit.Singh, Cottser, mortendk, LewisNyman: move comment.theme.css to classy

core/modules/comment/comment.libraries.yml

@@ -7,12 +7,6 @@ drupal.comment:
     - core/drupal
     - core/drupal.form
 
-drupal.comment.threaded:
-  version: VERSION
-  css:
-    theme:
-      css/comment.theme.css: {}
-
 drupal.comment-by-viewer:
   version: VERSION
   js:

core/modules/comment/comment.module

@@ -613,6 +613,7 @@ function template_preprocess_comment(&$variables) {
   $commented_entity = $comment->getCommentedEntity();
   $variables['comment'] = $comment;
   $variables['commented_entity'] = $commented_entity;
+  $variables['threaded'] = $variables['elements']['#comment_threaded'];
 
   $account = $comment->getOwner();
   $username = array(

core/modules/comment/src/CommentViewBuilder.php

@@ -183,7 +183,6 @@ protected function alterBuild(array &$build, EntityInterface $comment, EntityVie
 
       // Add indentation div or close open divs as needed.
       if ($build['#comment_threaded']) {
-        $build['#attached']['library'][] = 'comment/drupal.comment.threaded';
         $prefix .= $build['#comment_indent'] <= 0 ? str_repeat('</div>', abs($build['#comment_indent'])) : "\n" . '<div class="indented">';
       }
 

core/modules/comment/templates/comment.html.twig

@@ -41,6 +41,7 @@
  * - content_attributes: List of classes for the styling of the comment content.
  * - title_attributes: Same as attributes, except applied to the main title
  *   tag that appears in the template.
+ * - threaded: A flag indicating whether the comments are threaded or not.
  *
  * These variables are provided to give context about the parent comment (if
  * any):

core/themes/bartik/templates/comment.html.twig

@@ -41,6 +41,7 @@
  * - title_attributes: Same as attributes, except applied to the main title
  *   tag that appears in the template.
  * - content_attributes: List of classes for the styling of the comment content.
+ * - threaded: A flag indicating whether the comments are threaded or not.
  *
  * These variables are provided to give context about the parent comment (if
  * any):
@@ -63,6 +64,9 @@
  * @see template_preprocess_comment()
  */
 #}
+{% if threaded %}
+  {{ attach_library('classy/drupal.comment.threaded') }}
+{% endif %}
 {%
   set classes = [
     'comment',

core/themes/classy/classy.libraries.yml

@@ -9,3 +9,9 @@ book-navigation:
   css:
     theme:
       css/navigation/book.theme.css: {}
+
+drupal.comment.threaded:
+  version: VERSION
+  css:
+    theme:
+      css/comment/comment.theme.css: {}

core/themes/classy/templates/content/comment.html.twig

@@ -41,6 +41,7 @@
  * - content_attributes: List of classes for the styling of the comment content.
  * - title_attributes: Same as attributes, except applied to the main title
  *   tag that appears in the template.
+ * - threaded: A flag indicating whether the comments are threaded or not.
  *
  * These variables are provided to give context about the parent comment (if
  * any):
@@ -63,6 +64,9 @@
  * @see template_preprocess_comment()
  */
 #}
+{% if threaded %}
+  {{ attach_library('classy/drupal.comment.threaded') }}
+{% endif %}
 {%
   set classes = [
     'comment',