0.5.15lorg3.1 loses epochs on rh7.3/rh8.0/rh9 (promoteepoch?)

[Panu Matilainen]

On Tue, 8 Aug 2006, Axel Thimm wrote:

> On Tue, Aug 08, 2006 at 09:42:48AM +0300, Panu Matilainen wrote:
>>> A) We live in the promoteepoch world
>>>   In this prehistoric time it was unceivable that a package would
>>>   have an epoch of "0". A missing epoch was indeed a missing epoch
>>>   and nothing more or less. Unepoched dependencies and
>>>   rpm-comparisons had a sick algorithm which depended on the package
>>>   being installed or not.
>>>
>>>   BUT:
>>>
>>>   There were no explicit zero-epoch packages, neither were there
>>>   explicit zero-epoch in dependencies.
>>
>> Yes, but createrepo injects artificial zero epochs *everywhere*, and
>> that's the sole reason for this madness. You need to use createrepo -n
>> switch for repositories requiring promoteepoch behavior, that way it
>> doesn't add the false epochs.
>
> createrepo -n will break yum and smart support (which ATrpms offers
> for these old distros). What's the difference in removing the zero
> epochs in the creating of the metadata or dropping them when they are
> being read in the depsolver? It's effectively the same and we don't
> need to break compatibility with smart/yum.

It does matter, and we've been through this already... see below

>>> B) The modern times
>>>   promoteepoch was considered evil and the distributions fixed not to
>>>   depend on it. Even rpm was fixed to equal in comparisons no-epoch
>>>   to zero-epoch. But one day someone had the great idea to shove
>>>   zero-epochs everywhere. It doesn't serve any special purpose and
>>>   this idiom is being slowly abandoned to meet its cousing
>>>   "promoteepoch" soon.
>>>
>>>   Therefore explicit zero-epochs are nonsense and can be discarded.
>>>
>>> If we strip zero-epochs out of everything shouldn't we be fine?
>>>
>>> In case A) there weren't ever any explicit zero-epoch packages, so
>>> whatever repomd says, when --promotepeoch is used, we can assume that
>>> the zepo-epochs can be discarded.
>>
>> Perhaps in your repositories there are no explicit zero-epoch packages but
>> it's not an assumption apt can make generally.
>
> No, it's not about ATrpms, it's the vendor's repos that matter and in
> this case there are no zero epochs anywhere. I can't say anything about
> other distros but RHL/RHEL/FC, but there the assumption holds.
>
> Maybe have zero-epoch stripping a config option again to address any
> possibility of such a repo?

There ARE zero epochs in at least dependencies if not packages themselves, 
and in presence of epoch promotion stripping out existing zero epoch goes 
kaboom, see 
http://lists.laiskiainen.org/pipermail/apt-rpm-laiskiainen.org/2006-April/000071.html

We've tried every possible combination already (see the variants and the 
failures in the thread above): it's simply not possible to support systems 
requiring promoteepoch without untampered dependency information. Sorry 
folks, end of story.

 	- Panu -