[Aptitude-devel] Bug#702561: aptitude: resolver hints (Aptitude::ProblemResolver::Hints=reject openssh-server :UNINST) being ignored

[Axel Beckert]

Package: aptitude
Version: 0.6.8.2-1
Severity: normal

Hi,

according to http://people.debian.org/~abe/aptitude/en/ch02s03s05.html
"reject aptitude :UNINST" will prevent the resolver from accepting
solutions which remove aptitude.

I tried to make the following command (which is a stripped-down version
of a command that aptitude-robot would execute) not removing
openssh-server under any circumstances:

# aptitude full-upgrade '~U' openssh-client+ openssh-server:
The following packages will be REMOVED:
  libbsd0{u} libedit2{u} openssh-client{u}
0 packages upgraded, 0 newly installed, 3 to remove and 1 not upgraded.
Need to get 0 B of archives. After unpacking 2665 kB will be freed.
The following packages have unmet dependencies:
 openssh-server : Depends: openssh-client (= 1:6.0p1-3) but it is not
 going to be installed.
The following actions will resolve these dependencies:

     Remove the following packages:
1)     openssh-server



Accept this solution? [Y/n/q/?] ^C

But it didn't work out as expected:

# aptitude -P -o 'Aptitude::ProblemResolver::Hints=reject openssh-server :UNINST' full-upgrade '~U' openssh-client+ openssh-server:
The following packages will be REMOVED:
  libbsd0{u} libedit2{u} openssh-client{u}
0 packages upgraded, 0 newly installed, 3 to remove and 1 not upgraded.
Need to get 0 B of archives. After unpacking 2665 kB will be freed.
The following packages have unmet dependencies:
 openssh-server : Depends: openssh-client (= 1:6.0p1-3) but it is not going to be installed.
The following actions will resolve these dependencies:

     Remove the following packages:
1)     openssh-server

[ Worst solution for a remote administrated machine. BTDT. ]

Accept this solution? [Y/n/q/?] ^C
root at acromantula-domu1:~# aptitude -P -o 'Aptitude::ProblemResolver::Hints=reject openssh-server :UNINST' full-upgrade '~U' openssh-client+ openssh-server:
The following packages will be REMOVED:
  libbsd0{u} libedit2{u} openssh-client{u}
0 packages upgraded, 0 newly installed, 3 to remove and 1 not upgraded.
Need to get 0 B of archives. After unpacking 2665 kB will be freed.
The following packages have unmet dependencies:
 openssh-server : Depends: openssh-client (= 1:6.0p1-3) but it is not going to be installed.
The following actions will resolve these dependencies:

     Remove the following packages:
1)     openssh-server

[ This looks like a bug to me, hence the report. ]

Accept this solution? [Y/n/q/?] n
The following actions will resolve these dependencies:

     Keep the following packages at their current version:
1)     libbsd0 [0.4.2-1 (now, testing)]
2)     libedit2 [2.11-20080614-5 (now, testing)]

     Upgrade the following packages:
3)     openssh-client [1:6.0p1-3 (now) -> 1:6.0p1-4 (testing)]
4)     openssh-server [1:6.0p1-3 (now) -> 1:6.0p1-4 (testing)]

[ Would be ok, but is not intended. ]

Accept this solution? [Y/n/q/?] n
The following actions will resolve these dependencies:

     Keep the following packages at their current version:
1)     libbsd0 [0.4.2-1 (now, testing)]
2)     libedit2 [2.11-20080614-5 (now, testing)]
3)     openssh-client [1:6.0p1-3 (now)]

[ This is what I'm trying to achieve automatically. ]

Accept this solution? [Y/n/q/?] ^C

So despite I've set Aptitude::ProblemResolver::Hints to "reject
openssh-server :UNINST" as documented, aptitude proposes as first
solution to remove openssh-server.

Running just "aptitude -o 'Aptitude::ProblemResolver::Hints=reject" and
then interactively provoking this situation by pressing "+" on
openssh-client (but not on openssh-server) shows the same proposed
resolutions in the TUI.

Interestingly setting Aptitude::ProblemResolver::Remove-Level to maximum
comes closer to the targeted solution:

# aptitude -P -o 'Aptitude::ProblemResolver::Remove-Level=maximum' full-upgrade '~U' openssh-client+ openssh-server:
The following packages will be REMOVED:
  libbsd0{u} libedit2{u} openssh-client{u}
0 packages upgraded, 0 newly installed, 3 to remove and 1 not upgraded.
Need to get 0 B of archives. After unpacking 2665 kB will be freed.
The following packages have unmet dependencies:
 openssh-server : Depends: openssh-client (= 1:6.0p1-3) but it is not going to be installed.
The following actions will resolve these dependencies:

     Keep the following packages at their current version:
1)     libbsd0 [0.4.2-1 (now, testing)]
2)     libedit2 [2.11-20080614-5 (now, testing)]

     Upgrade the following packages:
3)     openssh-client [1:6.0p1-3 (now) -> 1:6.0p1-4 (testing)]
4)     openssh-server [1:6.0p1-3 (now) -> 1:6.0p1-4 (testing)]



Accept this solution? [Y/n/q/?] n
The following actions will resolve these dependencies:

     Keep the following packages at their current version:
1)     libbsd0 [0.4.2-1 (now, testing)]
2)     libedit2 [2.11-20080614-5 (now, testing)]
3)     openssh-client [1:6.0p1-3 (now)]



Accept this solution? [Y/n/q/?] ^C

I then tried to set Aptitude::ProblemResolver::Keep-All-Level to
minimum, but that doesn't seem to change the situation despite I would
have expect that this in general would lead to no action at all happen
quite often:

root at acromantula-domu1:~# aptitude -P -o 'Aptitude::ProblemResolver::Remove-Level=maximum' -o 'Aptitude::ProblemResolver::Keep-All-Level=minimum' full-upgrade '~U' openssh-client+ openssh-server:
The following packages will be REMOVED:
  libbsd0{u} libedit2{u} openssh-client{u}
0 packages upgraded, 0 newly installed, 3 to remove and 1 not upgraded.
Need to get 0 B of archives. After unpacking 2665 kB will be freed.
The following packages have unmet dependencies:
 openssh-server : Depends: openssh-client (= 1:6.0p1-3) but it is not going to be installed.
The following actions will resolve these dependencies:

     Keep the following packages at their current version:
1)     libbsd0 [0.4.2-1 (now, testing)]
2)     libedit2 [2.11-20080614-5 (now, testing)]

     Upgrade the following packages:
3)     openssh-client [1:6.0p1-3 (now) -> 1:6.0p1-4 (testing)]
4)     openssh-server [1:6.0p1-3 (now) -> 1:6.0p1-4 (testing)]



Accept this solution? [Y/n/q/?] n
The following actions will resolve these dependencies:

     Keep the following packages at their current version:
1)     libbsd0 [0.4.2-1 (now, testing)]
2)     libedit2 [2.11-20080614-5 (now, testing)]
3)     openssh-client [1:6.0p1-3 (now)]



Accept this solution? [Y/n/q/?] ^C


JFTR: It also seems to make no difference if I set these options on the
commandline or in /root/.aptitude/config.

-- System Information:
[Tested in a minimal virtual machine installed with "xen-create-image
--dist wheezy --hostname acromantula-domu1 --lvm vg0 --dhcp
--verbose --pygrub". Report written somewhere else.]