dagutil: use absolute_import

mercurial/dagutil.py

@@ -6,9 +6,10 b''
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
-from node import nullrev
-from i18n import _
+from __future__ import absolute_import
 
+from .i18n import _
+from .node import nullrev
 
 class basedag(object):
     '''generic interface for DAGs