GNU bug report logs - #20314
mdate-sh has undeterministic output

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Eric Dorland <eric <at> debian.org>
To: bug-automake <at> gnu.org
Cc: Reiner Herrmann <reiner <at> reiner-h.de>
Subject: Re: Bug#782345: automake: mdate-sh has undeterministic output
Date: Sun, 12 Apr 2015 14:50:09 -0400

[Message part 1 (text/plain, inline)]

* Reiner Herrmann (reiner <at> reiner-h.de) wrote:
> Source: automake-1.14
> Version: 1:1.14.1-4
> Severity: wishlist
> User: reproducible-builds <at> lists.alioth.debian.org
> Usertags: toolchain
> Tags: upstream
> X-Debbugs-CC: reproducible-builds <at> lists.alioth.debian.org
> 
> Hi!
> 
> While working on Debian's “reproducible builds” effort [1], we have
> noticed that the output of mdate-sh (which is part of automake, and
> shipped by some upstream source tarballs) can produce different
> output depending on the timezone.
> Different output of mdate-sh can then lead to further differences
> in the build process [2].
> 
> We already forwarded a patch to automake-patches <at> gnu.org, but it
> hasn't appeared yet in their mailing list archive (which looks a little
> dead with no new mails since January).
> The patch [3] fixes the timezone used by mdate-sh to UTC, which will
> always produce the same output independent of the timezone of the caller.
> 
> Regards,
>  Reiner
> 
> [1]: https://wiki.debian.org/ReproducibleBuilds
> [2]: https://wiki.debian.org/ReproducibleBuilds/TimezoneVarianceBecauseOfAutomakeMdate
> [3]: https://lists.alioth.debian.org/pipermail/reproducible-builds/Week-of-Mon-20150406/001380.html
> 

-- 
Eric Dorland <eric <at> kuroneko.ca>
43CF 1228 F726 FD5B 474C  E962 C256 FBD5 0022 1E93

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Message #8 received at 20314 <at> debbugs.gnu.org (full text, mbox):

From: Eric Dorland <eric <at> debian.org>
To: 20314 <at> debbugs.gnu.org
Cc: Reiner Herrmann <reiner <at> reiner-h.de>, 782345-forwarded <at> bugs.debian.org
Subject: Re: Bug#782345: automake: mdate-sh has undeterministic output
Date: Sun, 12 Apr 2015 16:56:10 -0400

[Message part 1 (text/plain, inline)]

Control: tags -1 patch

Patch forwarded upstream.

* Reiner Herrmann (reiner <at> reiner-h.de) wrote:
> Source: automake-1.14
> Version: 1:1.14.1-4
> Severity: wishlist
> User: reproducible-builds <at> lists.alioth.debian.org
> Usertags: toolchain
> Tags: upstream
> X-Debbugs-CC: reproducible-builds <at> lists.alioth.debian.org
> 
> Hi!
> 
> While working on Debian's “reproducible builds” effort [1], we have
> noticed that the output of mdate-sh (which is part of automake, and
> shipped by some upstream source tarballs) can produce different
> output depending on the timezone.
> Different output of mdate-sh can then lead to further differences
> in the build process [2].
> 
> We already forwarded a patch to automake-patches <at> gnu.org, but it
> hasn't appeared yet in their mailing list archive (which looks a little
> dead with no new mails since January).
> The patch [3] fixes the timezone used by mdate-sh to UTC, which will
> always produce the same output independent of the timezone of the caller.
> 
> Regards,
>  Reiner
> 
> [1]: https://wiki.debian.org/ReproducibleBuilds
> [2]: https://wiki.debian.org/ReproducibleBuilds/TimezoneVarianceBecauseOfAutomakeMdate
> [3]: https://lists.alioth.debian.org/pipermail/reproducible-builds/Week-of-Mon-20150406/001380.html
> 



-- 
Eric Dorland <eric <at> kuroneko.ca>
43CF 1228 F726 FD5B 474C  E962 C256 FBD5 0022 1E93

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Message #15 received at 20314 <at> debbugs.gnu.org (full text, mbox):

From: Mathieu Lirzin <mthl <at> gnu.org>
To: Reiner Herrmann <reiner <at> reiner-h.de>, Eric Dorland <eric <at> debian.org>
Cc: reproducible-builds <at> lists.alioth.debian.org,
 bug#20314 <20314 <at> debbugs.gnu.org>, automake-patches <at> gnu.org
Subject: Re: [PATCH] Make output of mdate-sh deterministic
Date: Fri, 15 Sep 2017 12:34:54 +0200

Hello,

Reiner Herrmann <reiner <at> reiner-h.de> writes:

> mdate-sh pretty-prints the modification time of a file.
> But it's output can vary depending on the timezone of
> the caller. Someone in timezone GMT-12 will get a different
> result (day) than someone in timezone GMT+12.
>
> As this output is also used to create/update stamp files,
> which influence the further build process, the build result
> can vary.
> To enable reproducible builds and to have a more deterministic
> build behavior, this change fixes the timezone to UTC.
>
> Signed-off-by: Reiner Herrmann <reiner <at> reiner-h.de>
> ---
>  lib/mdate-sh | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>

Applied with slight modifications in commit
7c25c996d1c7c212a5981aa0e9c4434b6f33f7b8

Thanks.

-- 
Mathieu Lirzin
GPG: F2A3 8D7E EB2B 6640 5761  070D 0ADE E100 9460 4D37

Message #22 received at 20314 <at> debbugs.gnu.org (full text, mbox):

From: Mattia Rizzolo <mattia <at> debian.org>
To: Mathieu Lirzin <mthl <at> gnu.org>
Cc: Reiner Herrmann <reiner <at> reiner-h.de>, Eric Dorland <eric <at> debian.org>,
 reproducible-builds <at> lists.alioth.debian.org, bug#20314 <20314 <at> debbugs.gnu.org>,
 automake-patches <at> gnu.org
Subject: Re: [PATCH] Make output of mdate-sh deterministic
Date: Sat, 16 Sep 2017 15:46:52 +0200

[Message part 1 (text/plain, inline)]

On Fri, Sep 15, 2017 at 12:34:54PM +0200, Mathieu Lirzin wrote:
> Applied with slight modifications in commit
> 7c25c996d1c7c212a5981aa0e9c4434b6f33f7b8

Great, thank you!

-- 
regards,
                        Mattia Rizzolo

GPG Key: 66AE 2B4A FCCF 3F52 DA18  4D18 4B04 3FCD B944 4540      .''`.
more about me:  https://mapreri.org                             : :'  :
Launchpad user: https://launchpad.net/~mapreri                  `. `'`
Debian QA page: https://qa.debian.org/developer.php?login=mattia  `-

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Message #25 received at 20314 <at> debbugs.gnu.org (full text, mbox):

From: Eric Dorland <eric <at> kuroneko.ca>
To: Mathieu Lirzin <mthl <at> gnu.org>
Cc: Reiner Herrmann <reiner <at> reiner-h.de>,
 reproducible-builds <at> lists.alioth.debian.org, bug#20314 <20314 <at> debbugs.gnu.org>,
 automake-patches <at> gnu.org
Subject: Re: [PATCH] Make output of mdate-sh deterministic
Date: Sat, 16 Sep 2017 21:57:28 -0400

[Message part 1 (text/plain, inline)]

This is a good change but it's not enough unfortunately to make it
reproducible.  mdate-sh also needs to support SOURCE_DATE_EPOCH. I'm
working on a patch for that.

* Mathieu Lirzin (mthl <at> gnu.org) wrote:
> Hello,
> 
> Reiner Herrmann <reiner <at> reiner-h.de> writes:
> 
> > mdate-sh pretty-prints the modification time of a file.
> > But it's output can vary depending on the timezone of
> > the caller. Someone in timezone GMT-12 will get a different
> > result (day) than someone in timezone GMT+12.
> >
> > As this output is also used to create/update stamp files,
> > which influence the further build process, the build result
> > can vary.
> > To enable reproducible builds and to have a more deterministic
> > build behavior, this change fixes the timezone to UTC.
> >
> > Signed-off-by: Reiner Herrmann <reiner <at> reiner-h.de>
> > ---
> >  lib/mdate-sh | 6 +++++-
> >  1 file changed, 5 insertions(+), 1 deletion(-)
> >
> 
> Applied with slight modifications in commit
> 7c25c996d1c7c212a5981aa0e9c4434b6f33f7b8
> 
> Thanks.
> 

-- 
Eric Dorland <eric <at> kuroneko.ca>
43CF 1228 F726 FD5B 474C  E962 C256 FBD5 0022 1E93

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Message #28 received at 20314 <at> debbugs.gnu.org (full text, mbox):

From: Mathieu Lirzin <mthl <at> gnu.org>
To: Reiner Herrmann <reiner <at> reiner-h.de>
Cc: reproducible-builds <at> lists.alioth.debian.org,
 bug#20314 <20314 <at> debbugs.gnu.org>, automake-patches <at> gnu.org
Subject: Re: bug#20314: [PATCH] Make output of mdate-sh deterministic
Date: Sun, 17 Sep 2017 10:49:57 +0200

Hello Eric,

Eric Dorland <eric <at> kuroneko.ca> writes:

> This is a good change but it's not enough unfortunately to make it
> reproducible.  mdate-sh also needs to support SOURCE_DATE_EPOCH. I'm
> working on a patch for that.

Thanks for working on that.

-- 
Mathieu Lirzin
GPG: F2A3 8D7E EB2B 6640 5761  070D 0ADE E100 9460 4D37

Message #31 received at 20314 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Reiner Herrmann <reiner <at> reiner-h.de>
Cc: Eric Dorland <eric <at> debian.org>, Gnulib bugs <bug-gnulib <at> gnu.org>,
 Mathieu Lirzin <mthl <at> gnu.org>, 782345-forwarded <at> bugs.debian.org,
 automake-patches <at> gnu.org, 20314 <at> debbugs.gnu.org,
 reproducible-builds <at> lists.alioth.debian.org
Subject: Re: bug#20314: [PATCH] Make output of mdate-sh deterministic
Date: Thu, 21 Sep 2017 20:21:25 -0700

[Message part 1 (text/plain, inline)]

Unfortunately that patch to Automake's mdate-sh is not portable, as TZ='UTC' is 
not a portable setting for the TZ environment variable. POSIX says you're 
supposed to use something like TZ='UTC0' instead. Although TZ='UTC' works when 
glibc is used, this is not necessarily true on other POSIX platforms.

I noticed this problem when recent Automake changes were merged into Gnulib, and 
installed the attached patch to the Automake master branch to fix this. Please 
review any other patches you may be using for reproducible builds, and fix them 
to use TZ='UTC0' instead of TZ='UTC'. Thanks.

For reference, here's the POSIX spec for TZ:

http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_03

and look for "TZ".

[0001-lib-mdate.sh-TZ-Use-portable-setting.patch (text/x-patch, attachment)]

Message #34 received at 20314 <at> debbugs.gnu.org (full text, mbox):

From: Mathieu Lirzin <mthl <at> gnu.org>
To: Paul Eggert <eggert <at> cs.ucla.edu>
Cc: Gnulib bugs <bug-gnulib <at> gnu.org>, Eric Dorland <eric <at> debian.org>,
 782345-forwarded <at> bugs.debian.org, automake-patches <at> gnu.org,
 20314 <at> debbugs.gnu.org, Reiner Herrmann <reiner <at> reiner-h.de>,
 reproducible-builds <at> lists.alioth.debian.org
Subject: Re: bug#20314: [PATCH] Make output of mdate-sh deterministic
Date: Fri, 22 Sep 2017 10:43:24 +0200

Hello Paul,

Paul Eggert <eggert <at> cs.ucla.edu> writes:

> Unfortunately that patch to Automake's mdate-sh is not portable, as
> TZ='UTC' is not a portable setting for the TZ environment
> variable. POSIX says you're supposed to use something like TZ='UTC0'
> instead. Although TZ='UTC' works when glibc is used, this is not
> necessarily true on other POSIX platforms.
>
> I noticed this problem when recent Automake changes were merged into
> Gnulib, and installed the attached patch to the Automake master branch
> to fix this. Please review any other patches you may be using for
> reproducible builds, and fix them to use TZ='UTC0' instead of
> TZ='UTC'. Thanks.
>
> For reference, here's the POSIX spec for TZ:
>
> http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_03
>
> and look for "TZ".

Thanks for fixing that and for the reference.

> From 5b240b3b36766045a47a6ad89ae5f4550e81d534 Mon Sep 17 00:00:00 2001
> From: Paul Eggert <eggert <at> cs.ucla.edu>
> Date: Thu, 21 Sep 2017 20:08:48 -0700
> Subject: [PATCH] * lib/mdate.sh (TZ): Use portable setting.

nitpick: I would prefer your future commit messages to include a summary
line before the list of modified files.

-- 
Mathieu Lirzin
GPG: F2A3 8D7E EB2B 6640 5761  070D 0ADE E100 9460 4D37

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