Bug#868843: xorg-server: please make the BUILD_{DATE,TIME} reproducible

[Chris Lamb <lamby@debian.org>]

tags 868843 - moreinfo
forwarded 868843 https://lists.x.org/archives/xorg-devel/2017-July/thread.html
thanks

Hi Julien,

Thanks for the quick followup. :)

> How portable is the change to non-gnu date?

My previous patch was not. The updated attached patch is compatible
with BSD date(1). I am removing the "moreinfo" tag, assuming that was
why you added it.

> Can you send this patch upstream per
> https://www.x.org/wiki/Development/Documentation/SubmittingPatches/?

Done: https://lists.x.org/archives/xorg-devel/2017-July/thread.html


Best wishes,

-- 
      ,''`.
     : :'  :     Chris Lamb, Debian Project Leader
     `. `'`      lamby@debian.org / chris-lamb.co.uk
       `-

From bb171c65af6ee0c8b48e9108b277b1f9ff21f978 Mon Sep 17 00:00:00 2001
From: Chris Lamb <chris@chris-lamb.co.uk>
Date: Thu, 20 Jul 2017 15:42:15 +0100
Subject: [PATCH] configure.ac: Make BUILD_{DATE,TIME} respect
 SOURCE_DATE_EPOCH if set

Whilst working on the Reproducible Builds effort [0], we noticed that
xorg-server could not be built reproducibly. One reason is because it
embeds a "current" build and date time.

This should be compatible with both GNU and BSD date(1).

 [0] https://reproducible-builds.org/
---
 configure.ac | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
index e202770c1..f10a94cb4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2405,9 +2405,15 @@ AC_DEFINE_DIR(PROJECTROOT, prefix, [Overall prefix])
 AC_DEFINE_DIR(SYSCONFDIR, sysconfdir, [sysconfdir])
 
 AC_SUBST([RELEASE_DATE])
-BUILD_DATE="`date +'%Y%m%d'`"
+DATE_FMT="%Y-%m-%d"
+TIME_FMT="1%H%M%S"
+BUILD_DATE="`date "+$DATE_FMT"`"
+BUILD_TIME="`date "+$TIME_FMT"`"
+if test "x$SOURCE_DATE_EPOCH" != "x"; then
+	BUILD_DATE="`date -u -d "@$SOURCE_DATE_EPOCH" "+$DATE_FMT" 2>/dev/null || date -u -r "$SOURCE_DATE_EPOCH" "+$DATE_FMT" 2>/dev/null || date -u "+$DATE_FMT"`"
+	BUILD_TIME="`date -u -d "@$SOURCE_DATE_EPOCH" "+$TIME_FMT" 2>/dev/null || date -u -r "$SOURCE_DATE_EPOCH" "+$TIME_FMT" 2>/dev/null || date -u "+$TIME_FMT"`"
+fi
 AC_SUBST([BUILD_DATE])
-BUILD_TIME="`date +'1%H%M%S'`"
 AC_SUBST([BUILD_TIME])
 
 DIX_CFLAGS="-DHAVE_DIX_CONFIG_H $XSERVER_CFLAGS"
-- 
2.13.3