From 3789b385b210bd8fdfa755a0ca435c11fa53290e Mon Sep 17 00:00:00 2001
From: Simon McVittie <smcv@debian.org>
Date: Sun, 23 Jul 2017 15:56:24 +0100
Subject: [PATCH] core: Don't decode the result of strftime if already tagged
 as UTF-8

It wasn't in old Perls, but might be in Perl >= 5.21.1 due to commit
https://perl5.git.perl.org/perl.git/commit/9717af6 (Closes: #869240)
---
 IkiWiki.pm       | 12 +++++++++---
 debian/changelog |  5 +++++
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/IkiWiki.pm b/IkiWiki.pm
index 6aa49229a..1eda16da1 100644
--- a/IkiWiki.pm
+++ b/IkiWiki.pm
@@ -1293,14 +1293,20 @@ sub formattime ($;$) {
 
 my $strftime_encoding;
 sub strftime_utf8 {
-	# strftime doesn't know about encodings, so make sure
+	# strftime didn't know about encodings in older Perl, so make sure
 	# its output is properly treated as utf8.
 	# Note that this does not handle utf-8 in the format string.
+	my $result = POSIX::strftime(@_);
+
+	if (Encode::is_utf8($result)) {
+		return $result;
+	}
+
 	($strftime_encoding) = POSIX::setlocale(&POSIX::LC_TIME) =~ m#\.([^@]+)#
 		unless defined $strftime_encoding;
 	$strftime_encoding
-		? Encode::decode($strftime_encoding, POSIX::strftime(@_))
-		: POSIX::strftime(@_);
+		? Encode::decode($strftime_encoding, $result)
+		: $result;
 }
 
 sub date_3339 ($) {
diff --git a/debian/changelog b/debian/changelog
index 97ab8b75f..9c114bc3a 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,9 +1,14 @@
 ikiwiki (3.20170623) UNRELEASED; urgency=medium
 
+  [ Joey Hess ]
   * htmlscrubber: Add support for the video tag's loop and muted
     attributes. Those were not in the original html5 spec, but have been
     added in the whatwg html living standard and have wide browser support.
 
+  [ Simon McVittie ]
+  * core: Don't decode the result of strftime if it is already tagged as
+    UTF-8, as it might be since Perl >= 5.21.1. (Closes: #869240)
+
  -- Joey Hess <id@joeyh.name>  Tue, 11 Jul 2017 15:48:39 -0400
 
 ikiwiki (3.20170622) unstable; urgency=medium