aptitude's removal of packages when upgrading

[Celejar <celejar@gmail.com>]

Hi,

I thought that I understood aptitude pretty well, although I'm no
search pattern guru, but I just noticed something that I hadn't quite
realized.  I'm running Sid, and I decided to bravely / foolhardily
upgrade my system, so I updated, and then hit 'U'.  The resolver showed
conflicts, so I did what I usually do, kept on hitting '.' to cycle
through the proposed solutions until I hit one that showed all keeps
and no removes.  Before hitting 'g', I ran down the list of aptitude's
planned actions and lo and behold, aptitude was planning to remove
apt-listbugs, since libgettext-ruby1.8 was to be upgraded to a version
which conflicts with apt-listbugs.

I had always assumed that such things would show up in the original
resolver solutions, that it would warn me that the upgrade was
incompatible with some package that I wanted installed.  I guess I was
wrong; apparently the resolver only flags inconsistencies between
packages that you've *currently* given contradictory orders about, such
as installing two incompatible packages, or installing one and removing
one of its dependencies, but it will happily remove stuff you've
already installed to comply with an upgrade request.

I guess this is really the same thing that we've all seen when we ask
aptitude to remove some package, and it willingly complies, even when
that means removing its dependencies; that's not called a conflict.
[Of course, in all the cases being discussed here, it does list its
intended actions and gives you a chance to cancel.]  Still, shouldn't
there be a safe-upgrade option, perhaps even the default, when using
the TUI?

Celejar
--
mailmin.sourceforge.net - remote access via secure (OpenPGP) email
ssuds.sourceforge.net - A Simple Sudoku Solver and Generator