[Aptitude-devel] Bug#691955: aptitude: Aptitude::ProblemResolver::SolutionCost does not support substraction

[Axel Beckert]

Package: aptitude
Version: 0.6.8.1-2
Severity: wishlist

Dear Maintainer,

The followingAptitude::ProblemResolver::SolutionCost example is the
aptitude manual:

from removals + 2 * canceled-actions

I tried to weight removals-of-manual higher than other removals and came
up with the following rule:

aptitude -o Aptitude::ProblemResolver::SolutionCost='10 * removals - 9 * removals-of-manual + canceled-actions' remove htop

Since a local metapackage depends on htop, the resolver started its
work. And threw the following errors:

E: Failed to parse the cost settings string: <none>:1:15: Expected EOF, got '-'.
E: Failed to parse the cost settings string: <none>:1:15: Expected EOF, got '-'.

A simpler, yet less practical SolutionCost value with which we were able
to reproduce the issue is:

aptitude -o Aptitude::ProblemResolver::SolutionCost='removals - canceled-actions' remove htop

It would be nice if Aptitude::ProblemResolver::SolutionCost would also
support substraction.


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-- System Information:
Debian Release: wheezy/sid
  APT prefers unstable
  APT policy: (990, 'unstable'), (900, 'testing'), (600, 'stable'), (200, 'experimental')
Architecture: i386 (i686)

Kernel: Linux 3.6-trunk-686-pae (SMP w/1 CPU core)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages aptitude depends on:
ii  aptitude-common           0.6.8.1-2
ii  libapt-pkg4.12            0.9.7.6
ii  libboost-iostreams1.49.0  1.49.0-3.1
ii  libc6                     2.13-36
ii  libcwidget3               0.5.16-3.4
ii  libept1.4.12              1.0.9
ii  libgcc1                   1:4.7.2-4
ii  libncursesw5              5.9-10
ii  libsigc++-2.0-0c2a        2.2.10-0.2
ii  libsqlite3-0              3.7.14.1-1
ii  libstdc++6                4.7.2-4
ii  libtinfo5                 5.9-10
ii  libxapian22               1.2.12-1
ii  zlib1g                    1:1.2.7.dfsg-13

Versions of packages aptitude recommends:
pn  apt-xapian-index                <none>
pn  aptitude-doc-en | aptitude-doc  <none>
ii  libparse-debianchangelog-perl   1.2.0-1
ii  sensible-utils                  0.0.7

Versions of packages aptitude suggests:
pn  debtags  <none>
pn  tasksel  <none>

-- no debconf information