Subject: Re: providing a feature/capability instead of specific package
To: Hubert Feyrer <>
From: Julio M. Merino Vidal <>
List: tech-pkg
Date: 10/14/2004 18:53:03
On Thu, 14 Oct 2004 18:35:47 +0200 (CEST)
Hubert Feyrer <> wrote:

> On Wed, 13 Oct 2004, Jeremy C. Reed wrote:
> > What about letting packages provide a feature or capability and then other
> > packages could depend on that feature/capability instead of a specific
> > package dependency?

I like the idea.

> This is what RPM does. How do you plan to resolve dependencies, i.e. map
> feature -> pkg/filename? (local disk, ftp and http, please)

I think that what RPM or Debian packages do is to pick up a default package
for each feature (at least Debian picked up exim for 'mta', IIRC).  This way,
if the feature is not installed, a package is picked up automatically;
otherwise, the one installed in the machine will be used.

For example, suppose we have the "mta" feature.  It could default to 'sendmail'
(so the dependencies can be satisfied just as we usually do).  Other packages,
such as postfix or exim, could also provide this feature: if one of these is
already installed, it will be used instead of sendmail.

It might also be a good idea to let the administrator change the defaults too;
i.e., map 'mta' to postfix.

>   - Hubert
> -- 
>                          ,,__
> If wishes were wings,  o"   )~  would fly.            -- Go!
>                          ''''

Julio M. Merino Vidal <>
The NetBSD Project -