diff -r b8b246cffdee -r 9e1f4c65f5f5 mercurial/templates/paper/changeset.tmpl
--- a/mercurial/templates/paper/changeset.tmpl	Sun Dec 21 14:34:07 2014 -0800
+++ b/mercurial/templates/paper/changeset.tmpl	Sat Jan 03 17:50:21 2015 +0800
@@ -51,7 +51,7 @@
  <td class="date age">{date|rfc822date}</td></tr>
 <tr>
  <th class="author">parents</th>
- <td class="author">{parent%changesetparent}</td>
+ <td class="author">{ifeq(count(parent), '2', parent%changesetparentdiff, parent%changesetparent)}</td>
 </tr>
 <tr>
  <th class="author">children</th>