Bug#411657: Transition from sarge-etch for zope packages

[Steve Langasek]

On Wed, Feb 21, 2007 at 12:41:52PM +0100, Fabio Tranchitella wrote:
> Hello all,
>   I need some help to find a fix for #411657. The problem is that sarge
> included the zope2.7 package which requires python2.3, but python2.3 will
> not be shipped with etch and the current python package conflicts with it.

> Matthias uploaded zope-common 0.5.31 with the following change:

>   * debian/control: Depend on the unversioned python package.

> Which means that zope-common now depends on python (>= 2.4) instead of
> python2.4. After this change, upgrading from sarge to etch means that the
> sarge version of python2.3 will be uninstalled as well as zope2.7, which I
> would like to avoid. It will be common for our users to upgrade from sarge
> to etch with sites running zope2.7, and it would be a good thing to let
> them run both in order to manually upgrade their instances.

> See here:

> $ apt-cache show python | grep Conflicts
> Conflicts: python2.3 (<< 2.3.5-14), python2.1 (<= 2.1.2), python-xmlbase,
> python-csv, python-bz2, python-base, python-central (<< 0.5.5)

> I think that changing the dependency on zope-common to something like:

> Depends: python (>= 2.4) | python2.4, ...

> would do the trick,

No, this would definitely be wrong.  The package either uses
/usr/bin/python2.4 as an interpreter or it uses /usr/bin/python -- whichever
one it uses is the package it should be depending on.

Using /usr/bin/python and depending on python (>= 2.4) has the advantage
that the package will be automatically compatible with future versions of
python, introducing the possibility of a smoother upgrade for etch->lenny.
This shouldn't be considered to outweigh having a smooth upgrade for
sarge->etch though; OTOH, I also don't see why it's important to avoid
removal of zope2.7 on upgrade, it /is/ an obsolete package from the etch
perspective.

-- 
Steve Langasek                   Give me a lever long enough and a Free OS
Debian Developer                   to set it on, and I can move the world.
vorlon at debian.org                                   http://www.debian.org/