Bug#773323: perl: Wheezy->Jessie upgrade breaks wheezy pdl

[Niko Tyni]

On Tue, Dec 16, 2014 at 11:06:25PM +0100, Henning Glawe wrote:
> Control: clone 729220 -1
> Control: reassign -1 perl
> Control: retitle -1 perl: Wheezy->Jessie upgrade breaks wheezy pdl
> 
> There is a problem in wheezy's version of pdl, showing during the
> wheezy -> jessie update.
> 
> Could you please add a 'Breaks: pdl (<1:2.007)' to jessies perl
> packages ?

Sure. Just a few points/notes:

- is (<<1:2.007) correct? I see 1:2.007-2.1+b1 was the first one on i386
  that got built against perl 5.20, so technically the jessie perl breaks
  all the earlier ones, right? Also, AIUI the actual source change that
  fixes the breakage going forward is in 1:2.007-4 so it seems using
  that would be the most robust (think downstream distributions that
  might be upgrading their perl versions in a different schedule.)

  So is (<< 1:2.007-4) OK with you?

- which perl packages need this?

  The minimal recipe I could come up for this is
   # wheezy base chroot
   apt-get install libpdl-stats-perl
   dpkg --unpack perl-modules_5.20.1-3_all.deb # from jessie
   dpkg --remove libpdl-stats-perl

  or, alternatively,
   # wheezy base chroot
   apt-get install libpdl-stats-perl
   dpkg -i libc6_2.19-13_amd64.deb
   dpkg --unpack perl-base_5.20.1-3_amd64.deb 
   dpkg --remove libpdl-stats-perl

  Interestingly, unpacking the new 'perl' package alone doesn't trigger the
  failure.

  So it looks like we need the Breaks in both perl-base and perl-modules.

- is Breaks sufficient, or do we need Conflicts?

  Dependency guarantees around 'postinst triggered' are not quite clear to me.
  I assume 'postinst triggered' will not be called before the package is
  configured, in which case I expect Breaks should be enough (as it will
  guarantee that the old pdl package gets deconfigured, and the new pdl package
  won't be configured before its dependencies are installed.)

  Will test this, but any advice is appreciated.

I hope to be able to upload a fix this weekend, assuming the version number
thing above is confirmed one way or another.
-- 
Niko Tyni   ntyni at debian.org