Re: Zero epoch vs no epoch (patch)

On Sat, 29 Apr 2006, seth vidal wrote:

> On Sat, 2006-04-29 at 13:32 -0700, Panu Matilainen wrote:
>> On Sat, 29 Apr 2006, Christoph Thiel wrote:
>>
>>> On Sat, 29 Apr 2006, Panu Matilainen wrote:
>>>
>>>>>>  - Even if no epoch is specified, the metadata still specifies this
>>>>>>    as "0".  For most code paths this is no problem as for all
>>>>>>    comparisons of version data, a missing epoch is the same as a "0"
>>>>>>    epoch. This should not be a huge problem and would be only a
>>>>>>    cleanup item for the repodata.
>>>>>
>>>>> what does removing 0-epoch items buy us?
>>>>
>>>> What it buys is support for ancient rpm versions. Remember those
>>>> monstrosities where non-existing epoch is not equal to zero epoch, epoch
>>>> promotion and all that fun? I couldn't personally care less about the
>>>> old rpm versions but there are people who do care, for example Dag and
>>>> Matthias:
>>>> http://lists.freshrpms.net/pipermail/freshrpms-list/2006-April/014022.html
>>>>
>>>> Removing those zero epochs from repodata makes yum rather unhappy, dunno
>>>> about smart, so changing the default is not really a possibility. But
>>>> then neither supports the prehistoric versions that are of concern here.
>>>> Attached quick hack of a patch adds a switch to turn off adding those
>>>> artificial zero epochs, using this as necessary this should be enough to
>>>> allow using repodata with full rpm 3.0.x - 4.4.x range.
>>>
>>> When we were implementing rpm-md support for our online update channels,
>>> we stumbled over the epoch thingy as well, but had to add the epoch="0",
>>> to keep yum & smart intact. The funny thing we found was the fact that rpm
>>> itself doesn't handel an empty epoch consistently -- if there is any
>>> interest, I'll dig into the rpm code again to give you the details...
>>
>> IIRC rpm 4.2.1 was the first version of rpm to handle zero vs no epoch
>> equally and sanely, except for a bug in "freshen" case where it did matter
>> for rpm itself until recently (fixed last year or so). Other than the
>> freshen issue (which didn't affect depsolvers) I'm not aware of any
>> *recent* issues wrt epochs. Before rpm 4.2.1 there was the promote-epoch
>> behavior on by default and whatnot.. a horrid mess especially thinking
>> about it afterwards :)
>>
>
> Why do you need this? What system isn't using a modern version of rpm?

I don't need it, users do. For example RHEL 2.1 has rpm 4.0.x and it's 
supported until May 2009, and RHL 9 and derivates (which is also affected 
by this) even if long since unsupported is popular still. Not to mention 
various non-RH distros, various Suse enterprise products as I understand 
it etc.

There are good reasons people would like to get rid of the old apt 
metadata format:
- it has artificial limitations on directory structure
- yet another data format to deal with + tools to run it

 	- Panu -