diff -r af0e88e64ede -r 88e7105b5cd9 mercurial/templatekw.py
--- a/mercurial/templatekw.py	Tue Jun 12 20:43:56 2018 -0400
+++ b/mercurial/templatekw.py	Wed Jun 13 21:57:24 2018 +0900
@@ -240,7 +240,9 @@
 def showdate(context, mapping):
     """Date information. The date when the changeset was committed."""
     ctx = context.resource(mapping, 'ctx')
-    return templateutil.date(ctx.date())
+    # the default string format is '<float(unixtime)><tzoffset>' because
+    # python-hglib splits date at decimal separator.
+    return templateutil.date(ctx.date(), showfmt='%d.0%d')
 
 @templatekeyword('desc', requires={'ctx'})
 def showdescription(context, mapping):