diff -r 4de15c54e59f -r c6061cadb400 mercurial/formatter.py
--- a/mercurial/formatter.py	Thu Feb 08 23:27:24 2018 +0530
+++ b/mercurial/formatter.py	Thu Feb 15 17:18:26 2018 +0100
@@ -126,6 +126,7 @@
     templater,
     util,
 )
+from .utils import dateutil
 
 pickle = util.pickle
 
@@ -243,7 +244,7 @@
     @staticmethod
     def formatdate(date, fmt):
         '''stringify date tuple in the given format'''
-        return util.datestr(date, fmt)
+        return dateutil.datestr(date, fmt)
     @staticmethod
     def formatdict(data, key, value, fmt, sep):
         '''stringify key-value pairs separated by sep'''