[Bug 1504788] [NEW] aptitude is capable of suggesting solutions that do not include installing the specifically requested package

[quequotion]

Public bug reported:

I came across this when trying to fix an installation (broken by "apt-
get dist-upgrade") by reinstalling its desktop metapackage (which apt
had removed, in order to remove its dependencies and install conflicting
packages that were neither packages I requested or dependencies thereof,
but that's a different problem).

I tried "aptitude install ubuntukylin-desktop"

aptitude suggested a variety of solutions to the conundrum apt had
created, none of which involved installing the package I asked for. Even
after trying one, thinking I might be able to install it on a second
pass, aptitude continued to make suggestions that excluded the
possibility of installing the one single package I asked for.

In the end it took three passes--cycling through half a dozen
suggestions each time--and I will spend the next several hours trying to
figure out what was broken in the process (numerous unrelated packages
were forcibly removed by aptitude). My particular case will not be
reproducible as it depends on my package selections and resulted from
apt making a terrible, random mess of a dist-upgrade.

You don't have to reproduce my particular case to verify the problem.
You don't need any of my configuration files. The problem is that
aptitude is *capable* of suggesting solutions that do not include the
single package it was asked to install. If a user asks aptitude to
install a single package, it should look for a solution that results in
installing that package and not otherwise.

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: aptitude 0.7-1ubuntu1.1
Uname: Linux 4.1.0-pf1+ i686
ApportVersion: 2.19.1-0ubuntu2
Architecture: i386
Date: Sat Oct 10 22:36:06 2015
InstallationDate: Installed on 2014-12-30 (284 days ago)
InstallationMedia: Ubuntu-Kylin 14.04.1 LTS "Trusty Tahr" - Release i386 (20140722.1)
JournalErrors:
 No journal files were found.
 -- No entries --
SourcePackage: aptitude
UpgradeStatus: No upgrade log present (probably fresh install)

** Affects: aptitude (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: apport-bug i386 third-party-packages wily

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https://bugs.launchpad.net/bugs/1504788

Title:
  aptitude is capable of suggesting solutions that do not include
  installing the specifically requested package

Status in aptitude package in Ubuntu:
  New

Bug description:
  I came across this when trying to fix an installation (broken by "apt-
  get dist-upgrade") by reinstalling its desktop metapackage (which apt
  had removed, in order to remove its dependencies and install
  conflicting packages that were neither packages I requested or
  dependencies thereof, but that's a different problem).

  I tried "aptitude install ubuntukylin-desktop"

  aptitude suggested a variety of solutions to the conundrum apt had
  created, none of which involved installing the package I asked for.
  Even after trying one, thinking I might be able to install it on a
  second pass, aptitude continued to make suggestions that excluded the
  possibility of installing the one single package I asked for.

  In the end it took three passes--cycling through half a dozen
  suggestions each time--and I will spend the next several hours trying
  to figure out what was broken in the process (numerous unrelated
  packages were forcibly removed by aptitude). My particular case will
  not be reproducible as it depends on my package selections and
  resulted from apt making a terrible, random mess of a dist-upgrade.

  You don't have to reproduce my particular case to verify the problem.
  You don't need any of my configuration files. The problem is that
  aptitude is *capable* of suggesting solutions that do not include the
  single package it was asked to install. If a user asks aptitude to
  install a single package, it should look for a solution that results
  in installing that package and not otherwise.

  ProblemType: Bug
  DistroRelease: Ubuntu 15.10
  Package: aptitude 0.7-1ubuntu1.1
  Uname: Linux 4.1.0-pf1+ i686
  ApportVersion: 2.19.1-0ubuntu2
  Architecture: i386
  Date: Sat Oct 10 22:36:06 2015
  InstallationDate: Installed on 2014-12-30 (284 days ago)
  InstallationMedia: Ubuntu-Kylin 14.04.1 LTS "Trusty Tahr" - Release i386 (20140722.1)
  JournalErrors:
   No journal files were found.
   -- No entries --
  SourcePackage: aptitude
  UpgradeStatus: No upgrade log present (probably fresh install)

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