[Aptitude-devel] Bug#570377: Bug#570377: aptitude chooses to remove packages instead of upgrading

[Daniel Hartwig]

On 2 February 2014 14:56, Chris Tillman <toff.tillman at gmail.com> wrote:
>
> Tags: patch
>
> I think the root of the problem (removing being preferential to upgrading
> in Aptitude's worldview) is that the safe-level and remove-level default
> scores are the same.
>

Hi

Thanks for your interest and patch.  Unfortunately, it is not an
acceptable solution to apply to the _default_ settings.

There is nothing fundamentally better or worse about either removals
or installs, in some situations you might find this:

 solution 1: upgrade 20 packages
 solution 2: remove 1

Whichever is more preferable in these situations is up to the
individual user to decide based on whatever particular packages are
suggested for upgrade, install, or removal—aptitude can not know how
the user values those individual actions.  The point of the safety
cost _levels_ is to broadly class categories of actions, and in that
sense, installing or upgrading to a package in the target release is
no better or worse than removing a non-essential package.

Tweaking the default settings as per the patch here is not to be done
lightly.  Considering the architecture of the problem resolver as a
whole, it is not an acceptable solution.

I recommend any of Axels suggestions for individual users who are
bothered by this, especially the comments about guiding the resolver
by e.g. rejecting particular actions _before_ asking for the next
solution.  This is also covered in the users manual, _Resolving
Dependencies Interactively_.  That is the most effective way of
informing the resolver about your desires.

Regards