diff -r 19c4b93cb7d6 -r 41957e50e109 mercurial/hgweb/webutil.py
--- a/mercurial/hgweb/webutil.py	Sun Nov 08 23:42:44 2015 -0800
+++ b/mercurial/hgweb/webutil.py	Tue Nov 10 23:02:59 2015 +0800
@@ -297,8 +297,8 @@
 
     return {
         "author": ctx.user(),
-        "parent": parents(ctx, rev - 1),
-        "child": children(ctx, rev + 1),
+        "parent": lambda **x: parents(ctx, rev - 1),
+        "child": lambda **x: children(ctx, rev + 1),
         "changelogtag": showtags,
         "desc": ctx.description(),
         "extra": ctx.extra(),