Bug#504880: Disambiguate "installed" for packages

[Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr>]

On Sun, Aug 15, 2010 at 02:57:18PM -0500, Jonathan Nieder wrote:
> Russ Allbery wrote:
> 
> > How about this?
> > 
> > 	      <p>
> > 		The <tt>Depends</tt> field should also be used if the
> > 		<prgn>postinst</prgn> or <prgn>prerm</prgn> scripts
> > 		require the depended-on package to be unpacked or
> > 		configured in order to run, or if the dependend-on package
> > 		is desirable for cleanup done by <prgn>postrm</prgn>.
> 
> I guess I am confused; when in practice is Depends better than Suggests for
> this last purpose?

This is needed for purge: at purge time, it cannot be assumed that dependencies are installed
(hence desirable) however in the case when we purge the dependencies at the same time the
dependency is useful so that dpkg purges the packages in the right order (i.e. the dependencies
last) so that the purge can proceed. This would not work with Suggests or Recommends.

Cheers,
-- 
Bill. <ballombe@debian.org>

Imagine a large red swirl here.