Current situation of amarok, and of latex tools

[Christopher James Halse Rogers]

On Mon, 2009-05-25 at 02:22 +0100, Dmitrijs Ledkovs wrote:
> 2009/5/25 Markus Hitter <mah at jump-ing.de>:
> >
> > Am 25.05.2009 um 00:01 schrieb Jan Claeys:
> >
> >> And to be honest, I don't see how we can make more people use alpha
> >> versions on their "I need this for work" system...
> >
> > Craft a system where people can switch back and forth between
> > different package versions. "This update broke foo?" -> Report a bug
> > and switch foo back to the previous version -> Damage gone, user happy.
> >
> > Programmers do something similar with their source code already, why
> > not with binary packages?
> >
> >
> > Markus
> >
> > - - - - - - - - - - - - - - - - - - -
> > Dipl. Ing. Markus Hitter
> > http://www.jump-ing.de/
> 
> Dowgrades are not supported..... it's the basics behind apt and dpkg.

That's not really a particularly good answer.  *Why* aren't downgrades
supported is what I interpret Markus to be asking.

The immediate reason is because of the *policy* that downgrades aren't
supported - thus, they aren't tested, and little or no effort is made to
ensure that they work.  For most packages, most of the time, downgrading
should work just fine because the situations where downgrades fail
aren't the common case - most package upgrades won't involve config file
changes, won't require maintainer scripts to do funky things, and won't
convert the user's data into an incompatible format.

I think the rationale behind this policy is that the general case
*cannot* be handled reasonably - in particular, package updates *can*
trigger the program to migrate the user's data into a format that
previous versions can't read.  Supporting package downgrades means
supporting package downgrades in general, and this would require that
package maintainers write back-conversion utilities where necessary.

Having some sort of "roll back to previous package version" button might
be a nice idea, though it would need to be designed in such a way that
made it clear there was no guarantee that it'd work.  I'm not sure
whether we'd be doing users a favour here.