[Yum-devel] pain and suffering and allowdowngrade

[seth vidal]

On Fri, 2008-10-24 at 15:49 -0700, Skahan, Vince wrote:
> How would the system know what version to downgrade to ? 


User specified or, whatever is lowest?

>   Consider the
> case where you've done multiple updates of a particular package along
> the way and you want to go to some intermediate step, or where multiple
> old versions exist in the repo(s) you have enabled.

oh, I know - the complications are without bound. Most users don't think
about this. They just want to downgrade back, magically, to
functionality.


> How would the system know where to get the rpm from (again) to do the
> downgrade ?  I've seen cases where intermediate versions disappear from
> some of the official repo mirrors in past Fedoras as time progressed.

Whatever is in the repodata is available. If it is not in the data, then
it can't happen.


> How would you address the reverse-requires issue ?   Yum has a great
> 'resolve deps when installing package-XYZ' feature where it figures out
> what other things you should have asked for as corequisites.  Would you
> get into a position where you'd need to calculate which
> previously-upgraded versions of other rpms would need to be backed down
> too (example - downgrade net-snmp which should downgrade its libs too,
> etc.)

Yes, theoretically the depsolving should sort of work for downgrades. In
practice it is not likely to.


-sv