diff -r e72697893c93 -r 8d6109b49b31 mercurial/templatekw.py
--- a/mercurial/templatekw.py	Sat Apr 21 19:01:35 2018 +0900
+++ b/mercurial/templatekw.py	Sat Mar 24 17:54:02 2018 +0900
@@ -240,7 +240,7 @@
 def showdate(context, mapping):
     """Date information. The date when the changeset was committed."""
     ctx = context.resource(mapping, 'ctx')
-    return ctx.date()
+    return templateutil.date(ctx.date())
 
 @templatekeyword('desc', requires={'ctx'})
 def showdescription(context, mapping):