Re: Priority & metainfo

[Jeff Johnson <jbj redhat com>]

On Mon, Jul 08, 2002 at 05:20:40PM -0300, Gustavo Niemeyer wrote:
> Hello everyone.
> 
> Jeff, I'd like to know what's your position about introducing a new
> flag, named "Priority" (RPMTAG_PRIORITY), in rpm. This flag would be
> equivalent to the one provided in dpkg, which tells how important to
> a system a package is (e.g. glibc and kernel have a high priority).
> That's an important information for automatic updating tools.
> 

Here's the problems I have putting Priority: *in* a package header:

1) Who determines what the priority should be? Me and rpm? No thanks ...

2) What is rpm supposed to do with a priority tag? "Nothing." as an answer
will only work until someone does some Neat! Cool! Wow! thing with the tag,
then rpm from the CLI will be expected to do the same, sigh.

3) What happens when -- just like the current Distribution: and Vendor:
tags -- the tag values rot?

4) What about legacy packages that don't have the tag?

OTOH, I have no problems at all with adding a headerSprintfExtension
(see lib/formats.c) in order to associate RPMTAG_PRIORITY *with* a package.
The easiest way to illustrate headerSprintfExtension is

	bash$ rpm -q --qf '[%{fsnames}: %{fssizes}\n]' <any-package>
	/: 9870213
	/proc: 0
	/proc/bus/usb: 0
	/dev/shm: 0
	/dev/pts: 0

A better example is specspo, which associates Group: et al i18n info
by doing a lookup with the package name as a primary key.


> This also makes me wonder, wouldn't it be interesting to include a macro
> which allowed one to include metainformation in a package? Something
> like:
> 
> Meta(Priority): Standard
> 
> This would include a pair "Priority" -> "Standard" in an array like
> RPMTAG_METAINFO. This would be a nice way to append metainformation to
> a header and still keep this package "cross-distribution".

I don't mean to pop you balloon, but macros ain't sufficiently well wired
on the install side of rpm to do more than dream. What is needed is a
hard and reliable definition of exactly when, where, and how macro expansions
would occur.

73 de Jeff

-- 
Jeff Johnson	ARS N3NPQ
jbj@redhat.com (jbj@jbj.org)
Chapel Hill, NC