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Re: Priority dependence



On Sun, 18 Jul 2010 11:04:10 -0700
Russ Allbery <rra@debian.org> wrote:

> Frans Pop <elendil@planet.nl> writes:
> 
> > Maybe we should consider changing the default prio for all library
> > packages to optional or lower, except for specific cases (e.g. libc)
> > where the lib itself can actually be considered part of the core system.
> 
> I would make a stronger argument than that: how much do we care about any
> priorities other than important, standard, and everything else? 

It is very worthwhile having a clear division between Required and
Important. A typical bootstrap should include Required but there is no
need for any of the important packages and any which may be useful can
be added explicitly. Please don't merge Important or lose the
distinction between Required and Important - Required is sufficiently
bloated already without adding Important. Far preferable (from an
embedded perspective) to drop Important and make everything else into a
default Priority (optional).

IMHO There is nothing in Important that deserves bringing in everything
else in Important. i.e. I'd welcome dropping Important, Optional and
Extra completely and only having one default bag for everything not
Priority: required or higher.

> Do we
> really care about the difference between required (insofar as required
> means something outside of the essential set) and important, or between
> optional and extra, for *any* package?

Yes. The difference between required and everything else *is* important
- the distinctions beyond that point are redundant. 
 
> The one remaining use case for priorities seems to be to be seed material
> for installation scenarios.  For that, there seem to be three basic
> installation bases that people are likely to want:
> 
> * Essential-only, usually only desirable in cases like build chroots.
>   Doesn't use priority at all, but should just start from the essential
>   packages and compute a dependency closure.  This seems to be what the
>   intention of Priority: required was, but I'm not sure I see why we
>   should have required separate from Essential: yes plus dependencies.
> 
> * Base installation.  The smallest possible installation you can put on a
>   regular system and have a working and usable text-mode computer on which
>   you can install other things and which looks like UNIX.  This seems to
>   be what Priority: important is supposed to give you.

I disagree, Priority: required is all that is necessary for that
purpose. Important does not constitute a collected set of packages
which all have the same usefulness. Nothing "important" is omitted by
omitting Priority: important in a base installation. Even apt is not
Priority: required and IMHO should not be so.

> I'm probably on weaker ground in merging required and important, but I'd
> like to know more background for why we have these levels and
> distinctions.

I'm away from my usual test installations right now but I am confident
that Important is not as it seems. It is a loose collection of packages
which, individually, are important to many situations but are not
*required* by all. Installing one Important package does not warrant
installing the rest.

-- 


Neil Williams
=============
http://www.data-freedom.org/
http://www.nosoftwarepatents.com/
http://www.linux.codehelp.co.uk/

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