[Rpm-metadata] One more bit

[Gustavo Niemeyer]

Hello folks,

I'm missing one more bit in the metadata format: "prerequires"
information.

My suggestion is to include something like:

<rpm:requires>
	<rpm:entry ... pre="1">
</rpm:requires>

For entries which are pre-dependencies. This information is
used, for example, in APT-RPM to correctly split transactions
when removable media (CDROM) is in use.

Jeff Johnson warns us that "PreRequires" is usually source
of confusion, since users don't understand the meaning of
such word clearly. I perfectly understand his concern, but I
have no immediate suggestion for replacing the concept/wording.

As a way to achieve consensus on the matter, I'd like to present
the following summary. Every online dependency solver I've seen
so far, when using this information (if using it at all), has the
following behavior:

- Requires: The given package must be present when the operation
            is over.
- PreRequires: The given package must be present in the same
               transaction.

So, I'd be glad if such information could be included in the
dependency details.

Thanks!

-- 
Gustavo Niemeyer
http://niemeyer.net