tasksel: forcefully removes packages when tasks overlap

Can confirm same problem on a Lucid virtualbox install.
Does not happen on one virtualbox Karmic install.

Likely dependent on state of packages on system.

I can confirm this bug on Ubuntu 10.04 Desktop i386, 2.6.32-22-generic-pae.
After first running the command "sudo tasksel install openssh-server" and then running the command "sudo tasksel remove openssh-server" packages from two meta packages got affected.
Several packages from both the ubuntu-desktop and the ubuntu-restricted-extras meta packages were removed.
I fixed it by running the command "sudo tasksel install ubuntu-desktop" and then reinstalling some packages that had been removed from the ubuntu-restricted-extras meta package.

Easy test, maverick, previously installed openssh-server:

sudo tasksel remove openssh-server

grep remove /var/log/dpkg.log | grep 23:11 # (just to filter to the relevant time)

2010-06-02 23:11:07 startup packages remove
2010-06-02 23:11:15 remove ubuntu-desktop 1.198 1.198
2010-06-02 23:11:16 remove gdm-guest-session 0.15 0.15
2010-06-02 23:11:16 remove gdm 2.30.2-0ubuntu1 2.30.2-0ubuntu1
2010-06-02 23:11:18 remove gnome-applets 2.30.0-1ubuntu1 2.30.0-1ubuntu1
2010-06-02 23:11:18 remove indicator-me 0.2.6-0ubuntu1 0.2.6-0ubuntu1
2010-06-02 23:11:19 remove indicator-applet-session 0.4.1-0ubuntu1 0.4.1-0ubuntu1
2010-06-02 23:11:19 remove indicator-applet 0.4.1-0ubuntu1 0.4.1-0ubuntu1
2010-06-02 23:11:19 remove gnome-session 2.30.0-0ubuntu1 2.30.0-0ubuntu1
2010-06-02 23:11:20 update-alternatives: run with --remove x-session-manager /usr/bin/gnome-session
2010-06-02 23:11:20 update-alternatives: link group x-session-manager fully removed
2010-06-02 23:11:21 remove gnome-panel 1:2.30.0-0ubuntu1 1:2.30.0-0ubuntu1
2010-06-02 23:11:22 remove gnome-control-center 1:2.30.1-0ubuntu1 1:2.30.1-0ubuntu1
2010-06-02 23:11:22 remove gnome-media 2.30.0-0ubuntu1 2.30.0-0ubuntu1
2010-06-02 23:11:23 remove gnome-orca 2.31.2-0ubuntu1 2.31.2-0ubuntu1
2010-06-02 23:11:24 remove gnome-settings-daemon 2.30.1-0ubuntu1 2.30.1-0ubuntu1
2010-06-02 23:11:25 remove gstreamer0.10-pulseaudio 0.10.23-1ubuntu1 0.10.23-1ubuntu1
2010-06-02 23:11:25 remove hpijs 3.10.2-2ubuntu2 3.10.2-2ubuntu2
2010-06-02 23:11:25 remove hplip 3.10.2-2ubuntu2 3.10.2-2ubuntu2
2010-06-02 23:11:27 remove indicator-sound 0.2.3-0ubuntu1 0.2.3-0ubuntu1
2010-06-02 23:11:28 remove pulseaudio-module-x11 1:0.9.22~0.9.21+stable-queue-32-g8478-0ubuntu15 1:0.9.22~0.9.21+stable-queue-32-g8478-0ubuntu15
2010-06-02 23:11:28 remove pulseaudio-module-gconf 1:0.9.22~0.9.21+stable-queue-32-g8478-0ubuntu15 1:0.9.22~0.9.21+stable-queue-32-g8478-0ubuntu15
2010-06-02 23:11:29 remove pulseaudio-module-bluetooth 1:0.9.22~0.9.21+stable-queue-32-g8478-0ubuntu15 1:0.9.22~0.9.21+stable-queue-32-g8478-0ubuntu15
2010-06-02 23:11:29 remove pulseaudio-esound-compat 1:0.9.22~0.9.21+stable-queue-32-g8478-0ubuntu15 1:0.9.22~0.9.21+stable-queue-32-g8478-0ubuntu15
2010-06-02 23:11:29 remove libcanberra-pulse 0.24-1ubuntu1 0.24-1ubuntu1
2010-06-02 23:11:29 remove pulseaudio 1:0.9.22~0.9.21+stable-queue-32-g8478-0ubuntu15 1:0.9.22~0.9.21+stable-queue-32-g8478-0ubuntu15
2010-06-02 23:11:30 remove libasound2-plugins 1.0.23-0ubuntu1 1.0.23-0ubuntu1
2010-06-02 23:11:30 remove libhpmud0 3.10.2-2ubuntu2 3.10.2-2ubuntu2
2010-06-02 23:11:31 remove pulseaudio-utils 1:0.9.22~0.9.21+stable-queue-32-g8478-0ubuntu15 1:0.9.22~0.9.21+stable-queue-32-g8478-0ubuntu15
2010-06-02 23:11:31 remove libpulse-browse0 1:0.9.22~0.9.21+stable-queue-32-g8478-0ubuntu15 1:0.9.22~0.9.21+stable-queue-32-g8478-0ubuntu15
2010-06-02 23:11:31 remove libpulse-mainloop-glib0 1:0.9.22~0.9.21+stable-queue-32-g8478-0ubuntu15 1:0.9.22~0.9.21+stable-queue-32-g8478-0ubuntu15
2010-06-02 23:11:32 remove libsdl1.2debian 1.2.14-4ubuntu1 1.2.14-4ubuntu1
2010-06-02 23:11:32 remove libsdl1.2debian-pulseaudio 1.2.14-4ubuntu1 1.2.14-4ubuntu1
2010-06-02 23:11:32 remove python-speechd 0....

This is also the case If I simply do:
sudo apt-get remove openssh-server^ (note the caret to mark as a task)

Hence adding a task for apt

I've tested this on current Debian testing, and the problem exists, but is less problematic, since there seems to be much less overlap in the Debian tasks.

However one example is if the tasks: ~t^desktop. ~t^gnome-desktop and ~t^laptop, are installed and then the ~t^laptop task is removed. This will result in the removal of e.g. wpasupplicant, network-manager and network-manager-gnome, all of which are also a part of the ~t^gnome-desktop task.
I will take this upstream to Debian.

I've been told that the package sets are indeed defined by tasksel, hence the apt task would be invalid.

Reported in Debian as http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=587046

@benjamin: please do not assign yourself or any one else to a bug unless you are actively working on resolving the issue. In this case, you can assign *yourself*, but should add a comment about it.

jeevithan: please do not assign yourself to the bug unless you are working on it, thanks.

In Debian this has been resolved indirectly since tasksel now uses metapackages instead of tasks to define sets, this change is not present in Ubuntu currently.

# sudo apt-get remove lamp-server^

Began removing my whole system. Force closed the terminal. I am glad I was reading the output, because my system still works for now (it just happened, so I will find out what damage was done).

Ok, here is some help to restore the system from "TTY_only" after tasksel removed important packages:

sudo apt-get install $(for i in $(cat /var/log/dpkg.log |grep -oP "(?<=`date +%Y-%m-%d`\s\d\d\:\d\d:\d\d\sremove)\s\S*\s"); do echo -n "$i "; done;)

Which basically looks in the dpkg.log for packages removed today and reinstalls them by handing the package-names over to apt-get. It also restores other packages :)

ola:
Please do not assign yourself to the bug unless you are working on it, thanks.

eMcE:
Yes, that might work in some cases.
It would be advisable though, to first do the grepping and then review the result before trying to reinstall everything from it, I have a feeling things could go even worse if one is not being careful there...

Also worth noting is that any automatically-installed states will have been lost, so that's something to keep in mind as well...

What is going on with this bug?

I wanted to install SSH Server on my new Ubuntu 18.04 system, and so unchecked the things that were installed already, checked SSH Server .. and it's been busily uninstalling EVERYTHING. This is a disaster.

I just ran into this bug. Started uninstalling everything when I was removing lamp-server. Thankfully I caught it at about 15% and killed the session when I started noticing things disappearing. This is a critical disastrous bug. How has it not been touched in so long?

If it's not going to get fixed, at least remove tasksel out of production or at least remove the remove function from it. This is ridiculous.

WTF. I was uninstalling the ubuntu-mate-desktop task with tasksel (while ubuntu-desktop was still checked in the list), and it removed basically everything. Afterwards all tasks in the tasksel list were unchecked. This is definitely not the expected behavior: when I uncheck a specific task, I don't expect other tasks to be removed as well.

I suggest to disable the package-removal functionality in tasksel. Alternatively, show a big warning when tasksel is about to remove anything. There are lots of warning posts about this behavior of tasksel all over the net, but if the warning does not appear in the application itself, I'm unlikely to see it before it's too late.

Like Elias M Ward, I installed lamp-server using taskel. It didn't work as expected and upon uninstalling, taskel removed everything. I came back to my desk, and the system was shot. No network, no desktop, nothing. Luckily, this was a fresh install, so a reinstall was the quickest way to get a usable system.

Very, very poorly thought out.

Ten years later? Wow.

The easiest way out would be to just remove tasksel once the d-i images are gone, and it's no longer needed.

Well, I wasn't as lucky as Colonel Angus and my system wasn't a fresh install. Love having my day and OS ruined by a ten year old bug that doesn't even have importance decided.

If you're not planning to ever fix it maybe just add a warning to taskel that this tool isn't fit for regular users and we should not follow tutorials and just use apt instead?

Today I used tasksel to add "lubuntu-desktop" to an "ubuntu-desktop" installation. Already installed and noticed by tasksel was additionally: "SSH-Service" and "Print Server".

The installation of "lubunut-desktop" went fine. I logged in to lubuntu-desktop and now I wanted to remove the "ubuntu-desktop" only ... because it is an odroid and disk space is precoius.

I ran tasksel and deselected "ubuntu-Desktop".

I was logged in and was able to see how my desktop, start menue, icons ... were removed / uninstalled until in the end a completely naked dektop was left. I was not able to run tasksel again. So I had to reinstall again. :((

Ubuntu 18.04 on odroid u3.
 Image name:
"ubuntu-18.04-4.16.0-v7-desktop-odroid-u2-u3-20190308_shrink.img.xz"