diff --git a/app/models/repository/mercurial.rb b/app/models/repository/mercurial.rb
index d7f58fc..010e3ab 100644
--- a/app/models/repository/mercurial.rb
+++ b/app/models/repository/mercurial.rb
@@ -44,6 +44,14 @@ class Repository::Mercurial < Repository
     changeset.scmid
   end
 
+  def branches
+    nil
+  end
+
+  def tags
+    nil
+  end
+
   def diff_format_revisions(cs, cs_to, sep=':')
     super(cs, cs_to, ' ')
   end