[Debian-med-packaging] Bug#729220: pdl: problems upgrading from wheezy due to triggers

[gregor herrmann]

On Mon, 15 Dec 2014 21:39:26 +0100, Henning Glawe wrote:

> > > raising the severity again since this is still occurring in the altree
> > > package. As it looks, altree removed the dependency on
> > > libpdl-stats-perl.
> > Ack (on the latter).
> actually, libpdl-stats-perl seems not to have been rebuilt for jessie's PDL
> version...

Oh :/ Also an interesting detail.
 
> The real problem seems to be my assumption that triggers get only called when
> all dependencies have been fulfilled...
> wheezy's pdl packages' triggers (in pdl.postinst) call perl scripts, which in
> turn use pdl modules.
> during the dist-upgrade, perl has been updated to jessie's version, while pdl
> is still at wheezy.

Interestingly this happens for both Andreas and you but not for me.

> perl API and module paths have been changed between wheezy and jessie, so the
> perl/pdl scripts used in pdl's triggers (used for updating documentation
> indices) fail, as they depend on the availability of PDL matching the
> presently installed perl.

I also thought about "interest" vs. "interest-noawait" but this
probably doesn't help if the wheezy postinst/triggers gets called :/
 
> > ... I couldn't reproduce the bug (in 3 tries), rebuilding your scenario
> > manually (i.e.: wheezy chroot, install altree, dist-upgrade).
> > libpdl-stats-perl gets removed for me, "Processing triggers for pdl"
> > never shows up. Excerpts from the dist-upgrade (full log attached):
> 
> I could reproduce the issues (via pbuilder/cowbuilder chroot):
> - build wheezy chroot (having the default pbuilder deps, i.e. build-essential
>   installed)
> - install altree (which pulls in pdl)
> - replace wheezy by jessie in /etc/apt/sources.list
> two upgrade paths run into different errors:
> 1.  'apt-get dist-upgrade' runs into the above mentioned error

That's exactly what I did as well.
(With an "apt-get update" before the dist-upgrade but I assume you
ran this too.)
 
> 2.a 'apt-get install dpkg apt' (works fine)
> 2.b 'apt-get dist-upgrade' fails with an apparently unrelated dpkg-trigger
>     related issue: 
>       (Reading database ... 15387 files and directories currently installed.)
>       Preparing to unpack .../libaudit1_1%3a2.4-1+b1_amd64.deb ...
>       Unpacking libaudit1:amd64 (1:2.4-1+b1) ...
>       dpkg: cycle found while processing triggers:
>        chain of packages whose triggers are or may be responsible:
>         man-db -> man-db
>        packages' pending triggers which are or may be unresolvable:
>         man-db: /usr/share/man
>       dpkg: error processing package man-db (--configure):
>        triggers looping, abandoned
>       Setting up libaudit1:amd64 (1:2.4-1+b1) ...
>       Errors were encountered while processing:
>        man-db
>       E: Sub-process /usr/bin/dpkg returned an error code (1)

Hm, is this still not fixed?
Anyway, different problem.
 
[..]
> > So for whatever reason, the order is different for me ...
> > No idea what this tells us.
> I think it tells us that my assumption (made already in wheezy), that a
> trigger gets only called when PDL is usable with the presently installed perl
> was wrong.
> some facts:
> - wheezy-pdl depends on perlapi-5.14.2
> - nevertheless pdl's documentation-update trigger gets called, while perl
>   has been already been replaced by the jessie version:

Ack. The question is how to get pdl to be updated earlier, I guess.

If I could reproduce the problem, I'd probably try Andreas'
suggestion to add a versioned Breaks against older pdl versions to
altree.
 

Cheers,
gregor

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