Issue #2463579 by tstoeckler: Add an ellipsis to truncated comment titles

core/modules/comment/src/CommentForm.php

@@ -301,7 +301,7 @@ public function buildEntity(array $form, FormStateInterface $form_state) {
       // 2) Strip out all HTML tags
       // 3) Convert entities back to plain-text.
       $comment_text = $comment->comment_body->processed;
-      $comment->setSubject(Unicode::truncate(trim(Html::decodeEntities(strip_tags($comment_text))), 29, TRUE));
+      $comment->setSubject(Unicode::truncate(trim(Html::decodeEntities(strip_tags($comment_text))), 29, TRUE, TRUE));
       // Edge cases where the comment body is populated only by HTML tags will
       // require a default subject.
       if ($comment->getSubject() == '') {

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

@@ -220,12 +220,12 @@ public function testAutoFilledSubject() {
     $body_text = 'Lorem ipsum Lorem ipsum Loreming ipsum Lorem ipsum';
     $comment1 = $this->postComment(NULL, $body_text, '', TRUE);
     $this->assertTrue($this->commentExists($comment1), 'Form comment found.');
-    $this->assertEqual('Lorem ipsum Lorem ipsum', $comment1->getSubject());
+    $this->assertEqual('Lorem ipsum Lorem ipsum…', $comment1->getSubject());
 
     // Break at 29 characters where there's no boundary before that.
     $body_text2 = 'LoremipsumloremipsumLoremingipsumLoremipsum';
     $comment2 = $this->postComment(NULL, $body_text2, '', TRUE);
-    $this->assertEqual('LoremipsumloremipsumLoremingi', $comment2->getSubject());
+    $this->assertEqual('LoremipsumloremipsumLoreming…', $comment2->getSubject());
   }
 
   /**