diff -r dd83aafdb64a -r 4f1f024353ae mercurial/obsolete.py
--- a/mercurial/obsolete.py	Fri Oct 12 19:25:08 2018 +0200
+++ b/mercurial/obsolete.py	Fri Oct 12 16:51:11 2018 +0200
@@ -600,7 +600,7 @@
                 raise ValueError(succ)
         if prec in succs:
             raise ValueError(
-                pycompat.sysstr(_('in-marker cycle with %s') % node.hex(prec)))
+                r'in-marker cycle with %s' % pycompat.sysstr(node.hex(prec)))
 
         metadata = tuple(sorted(metadata.iteritems()))
         for k, v in metadata: