diff -r 7c8524efd847 -r d5e1678026fd mercurial/commands.py
--- a/mercurial/commands.py	Thu Apr 05 14:21:37 2018 +0530
+++ b/mercurial/commands.py	Wed Apr 04 10:13:08 2018 -0700
@@ -4034,7 +4034,7 @@
             brev = None
 
             if checkout:
-                checkout = "%d" % repo.changelog.rev(checkout)
+                checkout = repo.changelog.rev(checkout)
 
                 # order below depends on implementation of
                 # hg.addbranchrevs(). opts['bookmark'] is ignored,