[Aptitude-devel] Bug#820116: aptitude-doc-en: downgrades are not documented in "Costs in the interactive dependency resolver"

Manuel A. Fernandez Montecelo manuel.montezelo at gmail.com
Tue Apr 5 16:26:41 UTC 2016

Control: severity - wishlist
Control: tags -1 + help

2016-04-05 16:25 Vincent Lefevre:
>Package: aptitude-doc-en
>Version: 0.7.8-1
>Severity: normal
>Downgrades are not mentioned at all in Section "Costs in the
>interactive dependency resolver" of the aptitude manual. Since
>they are not supported by Debian, one has the impression that
>they cannot be proposed, while they can be proposed in practice.
>In particular, it should be documented where they appear in Table 2.2
>on cost levels.

There are many things not supported, like using unstable or
experimental, or upgrading packages from oldstable to unstable, or from
a random point of snapshot.d.o to the present, than neither aptitude nor
other tools warn about.

Some of these combinations are not known to aptitude or the rest of
package management tools, they cannot know if the currently installed
package is from the last stable or from the stable 10 years ago.  Even
some of the upgrade problems from one stable version to the next are
only tested during the freeze, if at all.

Also, whether pkg-a_v1.3 is not safe to upgrade from pkg-a_v1.2 because
it's an ABI breakage is not known to these tools, and happens far more
often and causes many more problems than downgrades.  I downgrade
packages many times, if only for testing aptitude bugs, and I often
experience far more problems with day-to-day upgrades than with
downgrades, so YMMV.

I don't think that it's particularly useful to mention/highlight
downgrades, since these are not supposed to be seen by users using
stable and upgrading to the next stable, which is the only scenario that
Debian really supports.

Users who don't do this and mix versions in which aptitude can suggest
downgrades are on their own and should know how to deal with them.

In any case, I don't plan to work on this issue, tagging +help in the
case that somebody feels like it.

Manuel A. Fernandez Montecelo <manuel.montezelo at gmail.com>

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