bug#23776: Perl's .pod files include timestamps, making Perl package builds non-deterministic

bug#23776: Perl's .pod files include timestamps, making Perl package builds non-deterministic

[Ludovic Courtès]

Here’s an example:

--8<---------------cut here---------------start------------->8---
$ diff -ru /gnu/store/fmib129w05hbwbikd7x48s37hvr8nrdf-perl-io-stringy-2.110 /gnu/store/fmib129w05hbwbikd7x48s37hvr8nrdf-perl-io-stringy-2.110-check
diff -ru /gnu/store/fmib129w05hbwbikd7x48s37hvr8nrdf-perl-io-stringy-2.110/lib/perl5/5.22.1/x86_64-linux/perllocal.pod /gnu/store/fmib129w05hbwbikd7x48s37hvr8nrdf-perl-io-stringy-2.110-check/lib/perl5/5.22.1/x86_64-linux/perllocal.pod
--- /gnu/store/fmib129w05hbwbikd7x48s37hvr8nrdf-perl-io-stringy-2.110/lib/perl5/5.22.1/x86_64-linux/perllocal.pod	1970-01-01 01:00:01.000000000 +0100
+++ /gnu/store/fmib129w05hbwbikd7x48s37hvr8nrdf-perl-io-stringy-2.110-check/lib/perl5/5.22.1/x86_64-linux/perllocal.pod	1970-01-01 01:00:01.000000000 +0100
@@ -1,4 +1,4 @@
-=head2 Thu Jun 16 11:29:36 2016: C<Module> L<IO::Stringy|IO::Stringy>
+=head2 Thu Jun 16 11:29:34 2016: C<Module> L<IO::Stringy|IO::Stringy>
 
 =over 4
 --8<---------------cut here---------------end--------------->8---

The problem is described in <git://git.debian.org/git/reproducible/notes.git>:

--8<---------------cut here---------------start------------->8---
timestamps_in_documentation_generated_by_podman:
  description: |
    The module Pod::Man includes timestamps in its embedded manpages:
    http://sources.debian.net/src/perl/latest/cpan/podlators/lib/Pod/Man.pm/?hl=1700#L977
    They should be based on the mtime of the original file.
  url: https://wiki.debian.org/ReproducibleBuilds/TimestampsInManpagesGeneratedByPodMan
  deterministic: True
--8<---------------cut here---------------end--------------->8---

Ludo’.

bug#23776: Perl's .pod files include timestamps, making Perl package builds non-deterministic

[Leo Famulari]

On Thu, Jun 16, 2016 at 01:33:46PM +0200, Ludovic Courtès wrote:
> The problem is described in <git://git.debian.org/git/reproducible/notes.git>:
> 
> --8<---------------cut here---------------start------------->8---
> timestamps_in_documentation_generated_by_podman:
>   description: |
>     The module Pod::Man includes timestamps in its embedded manpages:
>     http://sources.debian.net/src/perl/latest/cpan/podlators/lib/Pod/Man.pm/?hl=1700#L977
>     They should be based on the mtime of the original file.
>   url: https://wiki.debian.org/ReproducibleBuilds/TimestampsInManpagesGeneratedByPodMan

According to the information on this page, we should set POD_MAN_DATE
while building. Should we make the perl-build-system export this
variable? Set to SOURCE_DATE_EPOCH?

bug#23776: Perl's .pod files include timestamps, making Perl package builds non-deterministic

[Ludovic Courtès]

Leo Famulari <leo@famulari.name> skribis:

> On Thu, Jun 16, 2016 at 01:33:46PM +0200, Ludovic Courtès wrote:
>> The problem is described in <git://git.debian.org/git/reproducible/notes.git>:
>> 
>> --8<---------------cut here---------------start------------->8---
>> timestamps_in_documentation_generated_by_podman:
>>   description: |
>>     The module Pod::Man includes timestamps in its embedded manpages:
>>     http://sources.debian.net/src/perl/latest/cpan/podlators/lib/Pod/Man.pm/?hl=1700#L977
>>     They should be based on the mtime of the original file.
>>   url: https://wiki.debian.org/ReproducibleBuilds/TimestampsInManpagesGeneratedByPodMan
>
> According to the information on this page, we should set POD_MAN_DATE
> while building. Should we make the perl-build-system export this
> variable? Set to SOURCE_DATE_EPOCH?

Yes, that sounds like a good idea.

Thanks,
Ludo’.

bug#23776: Perl's .pod files include timestamps, making Perl package builds non-deterministic

[Leo Famulari]

On Fri, Jun 17, 2016 at 10:11:21AM +0200, Ludovic Courtès wrote:
> Leo Famulari <leo@famulari.name> skribis:
> 
> > On Thu, Jun 16, 2016 at 01:33:46PM +0200, Ludovic Courtès wrote:
> >> The problem is described in <git://git.debian.org/git/reproducible/notes.git>:
> >> 
> >> --8<---------------cut here---------------start------------->8---
> >> timestamps_in_documentation_generated_by_podman:
> >>   description: |
> >>     The module Pod::Man includes timestamps in its embedded manpages:
> >>     http://sources.debian.net/src/perl/latest/cpan/podlators/lib/Pod/Man.pm/?hl=1700#L977
> >>     They should be based on the mtime of the original file.
> >>   url: https://wiki.debian.org/ReproducibleBuilds/TimestampsInManpagesGeneratedByPodMan
> >
> > According to the information on this page, we should set POD_MAN_DATE
> > while building. Should we make the perl-build-system export this
> > variable? Set to SOURCE_DATE_EPOCH?
> 
> Yes, that sounds like a good idea.

Should I add a phase to %standard-phases in perl-build-system.scm [0]?

Should I define a new procedure set-POD_MAN_DATE [1] and add that
perl-build-system.scm's %standard-phases?

[0]
http://git.savannah.gnu.org/cgit/guix.git/tree/guix/build/perl-build-system.scm#n71

[1] As in...
http://git.savannah.gnu.org/cgit/guix.git/tree/guix/build/gnu-build-system.scm#n42

bug#23776: Perl's .pod files include timestamps, making Perl package builds non-deterministic

[Ludovic Courtès]

Leo Famulari <leo@famulari.name> skribis:

> On Fri, Jun 17, 2016 at 10:11:21AM +0200, Ludovic Courtès wrote:
>> Leo Famulari <leo@famulari.name> skribis:
>> 
>> > On Thu, Jun 16, 2016 at 01:33:46PM +0200, Ludovic Courtès wrote:
>> >> The problem is described in <git://git.debian.org/git/reproducible/notes.git>:
>> >> 
>> >> --8<---------------cut here---------------start------------->8---
>> >> timestamps_in_documentation_generated_by_podman:
>> >>   description: |
>> >>     The module Pod::Man includes timestamps in its embedded manpages:
>> >>     http://sources.debian.net/src/perl/latest/cpan/podlators/lib/Pod/Man.pm/?hl=1700#L977
>> >>     They should be based on the mtime of the original file.
>> >>   url: https://wiki.debian.org/ReproducibleBuilds/TimestampsInManpagesGeneratedByPodMan
>> >
>> > According to the information on this page, we should set POD_MAN_DATE
>> > while building. Should we make the perl-build-system export this
>> > variable? Set to SOURCE_DATE_EPOCH?
>> 
>> Yes, that sounds like a good idea.
>
> Should I add a phase to %standard-phases in perl-build-system.scm [0]?
>
> Should I define a new procedure set-POD_MAN_DATE [1] and add that
> perl-build-system.scm's %standard-phases?

Yes, sounds like the right approach to me.

Thank you.

Ludo’.

bug#23776: Perl's .pod files include timestamps, making Perl package builds non-deterministic

[Leo Famulari]

On Thu, Jun 16, 2016 at 11:39:27AM -0400, Leo Famulari wrote:
> On Thu, Jun 16, 2016 at 01:33:46PM +0200, Ludovic Courtès wrote:
> > The problem is described in <git://git.debian.org/git/reproducible/notes.git>:
> > 
> > --8<---------------cut here---------------start------------->8---
> > timestamps_in_documentation_generated_by_podman:
> >   description: |
> >     The module Pod::Man includes timestamps in its embedded manpages:
> >     http://sources.debian.net/src/perl/latest/cpan/podlators/lib/Pod/Man.pm/?hl=1700#L977
> >     They should be based on the mtime of the original file.
> >   url: https://wiki.debian.org/ReproducibleBuilds/TimestampsInManpagesGeneratedByPodMan
> 
> According to the information on this page, we should set POD_MAN_DATE
> while building. Should we make the perl-build-system export this
> variable? Set to SOURCE_DATE_EPOCH?

I noticed that Pod::Man is supposed to respect SOURCE_DATE_EPOCH, as of
the upstream module version 4.03 (released 2015-12-06). Does anyone know
how to check the version of the module bundled into perl?

[0]
https://metacpan.org/pod/Pod::Man#date

[1]
https://www.eyrie.org/~eagle/software/podlators/news.html

bug#23776: Perl's .pod files include timestamps, making Perl package builds non-deterministic

[Leo Famulari]

On Sun, Jun 19, 2016 at 01:31:54PM -0400, Leo Famulari wrote:
> I noticed that Pod::Man is supposed to respect SOURCE_DATE_EPOCH, as of
> the upstream module version 4.03 (released 2015-12-06). Does anyone know
> how to check the version of the module bundled into perl?

In Perl 5.24.0, the integrated podlators module was upgraded from 2.28
from 4.0.7 [0].

AIUI, changing perl-build-system will require rebuilding all Perl
packages. If so, how about updating Perl to 5.24.0 instead of changing
the build system?

Do Perl updates tend to break a lot of Perl packages? If so, changing
the build system and rebuilding might be done sooner than a Perl update,
since this change seems unlikely to break any packages.

Your advice requested :)

[0]
https://metacpan.org/pod/distribution/perl/pod/perldelta.pod#Updated-Modules-and-Pragmata

bug#23776: Perl's .pod files include timestamps, making Perl package builds non-deterministic

[Ludovic Courtès]

Leo Famulari <leo@famulari.name> skribis:

> On Sun, Jun 19, 2016 at 01:31:54PM -0400, Leo Famulari wrote:
>> I noticed that Pod::Man is supposed to respect SOURCE_DATE_EPOCH, as of
>> the upstream module version 4.03 (released 2015-12-06). Does anyone know
>> how to check the version of the module bundled into perl?
>
> In Perl 5.24.0, the integrated podlators module was upgraded from 2.28
> from 4.0.7 [0].
>
> AIUI, changing perl-build-system will require rebuilding all Perl
> packages. If so, how about updating Perl to 5.24.0 instead of changing
> the build system?
>
> Do Perl updates tend to break a lot of Perl packages? If so, changing
> the build system and rebuilding might be done sooner than a Perl update,
> since this change seems unlikely to break any packages.

Sorry for the super late reply.  I think we’ll have to update at some
point, so what about doing that in core-updates-next?

Thanks,
Ludo’.

bug#23776: Perl's .pod files include timestamps, making Perl package builds non-deterministic

[Ludovic Courtès]

Leo Famulari <leo@famulari.name> skribis:

> On Thu, Jun 16, 2016 at 11:39:27AM -0400, Leo Famulari wrote:
>> On Thu, Jun 16, 2016 at 01:33:46PM +0200, Ludovic Courtès wrote:
>> > The problem is described in <git://git.debian.org/git/reproducible/notes.git>:
>> > 
>> > --8<---------------cut here---------------start------------->8---
>> > timestamps_in_documentation_generated_by_podman:
>> >   description: |
>> >     The module Pod::Man includes timestamps in its embedded manpages:
>> >     http://sources.debian.net/src/perl/latest/cpan/podlators/lib/Pod/Man.pm/?hl=1700#L977
>> >     They should be based on the mtime of the original file.
>> >   url: https://wiki.debian.org/ReproducibleBuilds/TimestampsInManpagesGeneratedByPodMan
>> 
>> According to the information on this page, we should set POD_MAN_DATE
>> while building. Should we make the perl-build-system export this
>> variable? Set to SOURCE_DATE_EPOCH?
>
> I noticed that Pod::Man is supposed to respect SOURCE_DATE_EPOCH, as of
> the upstream module version 4.03 (released 2015-12-06). Does anyone know
> how to check the version of the module bundled into perl?

For the record, even though Pod::Man supposedly honors SOURCE_DATE_EPOCH
as of Perl 5.24, we still have this problem:

--8<---------------cut here---------------start------------->8---
$ diff -r /gnu/store/hczskszmhm2l65vy8nv990lzc5dk3ln9-perl-algorithm-c3-0.10{,-check}
diff -r /gnu/store/hczskszmhm2l65vy8nv990lzc5dk3ln9-perl-algorithm-c3-0.10/lib/perl5/5.24.0/x86_64-linux-thread-multi/perllocal.pod /gnu/store/hczskszmhm2l65vy8nv990lzc5dk3ln9-perl-algorithm-c3-0.10-check/lib/perl5/5.24.0/x86_64-linux-thread-multi/perllocal.pod
1c1
< =head2 Wed Jan 11 22:20:36 2017: C<Module> L<Algorithm::C3|Algorithm::C3>
---
> =head2 Wed Jan 11 22:20:34 2017: C<Module> L<Algorithm::C3|Algorithm::C3>
--8<---------------cut here---------------end--------------->8---

Ludo’.

bug#23776: Perl's .pod files include timestamps, making Perl package builds non-deterministic

[Marius Bakke]

[-- Attachment #1: Type: text/plain, Size: 2103 bytes --]

Ludovic Courtès <ludo@gnu.org> writes:

> Leo Famulari <leo@famulari.name> skribis:
>
>> On Thu, Jun 16, 2016 at 11:39:27AM -0400, Leo Famulari wrote:
>>> On Thu, Jun 16, 2016 at 01:33:46PM +0200, Ludovic Courtès wrote:
>>> > The problem is described in <git://git.debian.org/git/reproducible/notes.git>:
>>> > 
>>> > --8<---------------cut here---------------start------------->8---
>>> > timestamps_in_documentation_generated_by_podman:
>>> >   description: |
>>> >     The module Pod::Man includes timestamps in its embedded manpages:
>>> >     http://sources.debian.net/src/perl/latest/cpan/podlators/lib/Pod/Man.pm/?hl=1700#L977
>>> >     They should be based on the mtime of the original file.
>>> >   url: https://wiki.debian.org/ReproducibleBuilds/TimestampsInManpagesGeneratedByPodMan
>>> 
>>> According to the information on this page, we should set POD_MAN_DATE
>>> while building. Should we make the perl-build-system export this
>>> variable? Set to SOURCE_DATE_EPOCH?
>>
>> I noticed that Pod::Man is supposed to respect SOURCE_DATE_EPOCH, as of
>> the upstream module version 4.03 (released 2015-12-06). Does anyone know
>> how to check the version of the module bundled into perl?
>
> For the record, even though Pod::Man supposedly honors SOURCE_DATE_EPOCH
> as of Perl 5.24, we still have this problem:
>
> --8<---------------cut here---------------start------------->8---
> $ diff -r /gnu/store/hczskszmhm2l65vy8nv990lzc5dk3ln9-perl-algorithm-c3-0.10{,-check}
> diff -r /gnu/store/hczskszmhm2l65vy8nv990lzc5dk3ln9-perl-algorithm-c3-0.10/lib/perl5/5.24.0/x86_64-linux-thread-multi/perllocal.pod /gnu/store/hczskszmhm2l65vy8nv990lzc5dk3ln9-perl-algorithm-c3-0.10-check/lib/perl5/5.24.0/x86_64-linux-thread-multi/perllocal.pod
> 1c1
> < =head2 Wed Jan 11 22:20:36 2017: C<Module> L<Algorithm::C3|Algorithm::C3>
> ---
>> =head2 Wed Jan 11 22:20:34 2017: C<Module> L<Algorithm::C3|Algorithm::C3>
> --8<---------------cut here---------------end--------------->8---

Isn't this fixed by be12f4e27505edd87c4aa457fec43dd0fee23b79 from
'core-updates'?


[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 487 bytes --]

bug#23776: Perl's .pod files include timestamps, making Perl package builds non-deterministic

[Ludovic Courtès]

Marius Bakke <mbakke@fastmail.com> skribis:

> Ludovic Courtès <ludo@gnu.org> writes:
>
>> Leo Famulari <leo@famulari.name> skribis:
>>
>>> On Thu, Jun 16, 2016 at 11:39:27AM -0400, Leo Famulari wrote:
>>>> On Thu, Jun 16, 2016 at 01:33:46PM +0200, Ludovic Courtès wrote:
>>>> > The problem is described in <git://git.debian.org/git/reproducible/notes.git>:
>>>> > 
>>>> > --8<---------------cut here---------------start------------->8---
>>>> > timestamps_in_documentation_generated_by_podman:
>>>> >   description: |
>>>> >     The module Pod::Man includes timestamps in its embedded manpages:
>>>> >     http://sources.debian.net/src/perl/latest/cpan/podlators/lib/Pod/Man.pm/?hl=1700#L977
>>>> >     They should be based on the mtime of the original file.
>>>> >   url: https://wiki.debian.org/ReproducibleBuilds/TimestampsInManpagesGeneratedByPodMan
>>>> 
>>>> According to the information on this page, we should set POD_MAN_DATE
>>>> while building. Should we make the perl-build-system export this
>>>> variable? Set to SOURCE_DATE_EPOCH?
>>>
>>> I noticed that Pod::Man is supposed to respect SOURCE_DATE_EPOCH, as of
>>> the upstream module version 4.03 (released 2015-12-06). Does anyone know
>>> how to check the version of the module bundled into perl?
>>
>> For the record, even though Pod::Man supposedly honors SOURCE_DATE_EPOCH
>> as of Perl 5.24, we still have this problem:
>>
>> --8<---------------cut here---------------start------------->8---
>> $ diff -r /gnu/store/hczskszmhm2l65vy8nv990lzc5dk3ln9-perl-algorithm-c3-0.10{,-check}
>> diff -r /gnu/store/hczskszmhm2l65vy8nv990lzc5dk3ln9-perl-algorithm-c3-0.10/lib/perl5/5.24.0/x86_64-linux-thread-multi/perllocal.pod /gnu/store/hczskszmhm2l65vy8nv990lzc5dk3ln9-perl-algorithm-c3-0.10-check/lib/perl5/5.24.0/x86_64-linux-thread-multi/perllocal.pod
>> 1c1
>> < =head2 Wed Jan 11 22:20:36 2017: C<Module> L<Algorithm::C3|Algorithm::C3>
>> ---
>>> =head2 Wed Jan 11 22:20:34 2017: C<Module> L<Algorithm::C3|Algorithm::C3>
>> --8<---------------cut here---------------end--------------->8---
>
> Isn't this fixed by be12f4e27505edd87c4aa457fec43dd0fee23b79 from
> 'core-updates'?

Oh, probably!  I had forgotten about it, thanks for the heads-up.

Ludo’.

bug#23776: Perl's .pod files include timestamps, making Perl package builds non-deterministic

[Ludovic Courtès]

ludo@gnu.org (Ludovic Courtès) skribis:

> Marius Bakke <mbakke@fastmail.com> skribis:
>
>> Ludovic Courtès <ludo@gnu.org> writes:

[...]

>>> For the record, even though Pod::Man supposedly honors SOURCE_DATE_EPOCH
>>> as of Perl 5.24, we still have this problem:
>>>
>>> --8<---------------cut here---------------start------------->8---
>>> $ diff -r /gnu/store/hczskszmhm2l65vy8nv990lzc5dk3ln9-perl-algorithm-c3-0.10{,-check}
>>> diff -r /gnu/store/hczskszmhm2l65vy8nv990lzc5dk3ln9-perl-algorithm-c3-0.10/lib/perl5/5.24.0/x86_64-linux-thread-multi/perllocal.pod /gnu/store/hczskszmhm2l65vy8nv990lzc5dk3ln9-perl-algorithm-c3-0.10-check/lib/perl5/5.24.0/x86_64-linux-thread-multi/perllocal.pod
>>> 1c1
>>> < =head2 Wed Jan 11 22:20:36 2017: C<Module> L<Algorithm::C3|Algorithm::C3>
>>> ---
>>>> =head2 Wed Jan 11 22:20:34 2017: C<Module> L<Algorithm::C3|Algorithm::C3>
>>> --8<---------------cut here---------------end--------------->8---
>>
>> Isn't this fixed by be12f4e27505edd87c4aa457fec43dd0fee23b79 from
>> 'core-updates'?
>
> Oh, probably!  I had forgotten about it, thanks for the heads-up.

Closing this bug!

Ludo’.