Ubuntu messes up Kubuntu installation

Did you realise that you can do:
$ sudo apt-get install ubuntu-desktop kubuntu-desktop

And choose if you want to login into ubuntu session or kubuntu session without having two ubuntu systems installed ?!

Can you please either:

* attach /var/log/installer/* files

or

* run `apport-collect 1060893`

From the affected system?

And about the btrfs subvolume handling. Currently you must have @ as root volume. And that also means you will only be able to have on ubuntu/debian based system installed on btrfs.

See:
https://help.ubuntu.com/community/btrfs#The_btrfs-tools_command_.27.27set-default.27.27_will_break_Ubuntu.27s_layout

I can not boot the affected system because grub does not recognize it, means that it is not bootable anymore. I do not want to install ubuntu-desktop and kubuntu-desktop on one system - the menu gets huge and confusing by installing all standard apps from KDE and GNOME at the same time.

Atm I work with GNOME because Kubuntu is not bootable anymore (but it was before), as already mentioned. I attached files from "/@/var/log/installer/*" from Kubuntu (I hope I got you right with "affected system"). After installation of the first system I get a normal "/" folder with all subfolders like "/boot", "/usr", "/var", "/dev", "/etc", "/home", etc. After installing the second Quantal system ubiquity moves all that folders from the first system into "@" and "@home" on its partition. As a result the first system is not bootable and not even recognized by grub because there is no "initrd.img" in /boot, because /boot is now a subfolder of "@" which it was not before installing the second Ubuntu flavor. I really wonder for what purpose ubiquity does this. I even wonder why ubiquity touches other partitions outside the actual install partition at all. I always do manual partitioning in ubiquity and did not set any mountpoints on other partitions.

Now that I use standard Ubuntu (also on btrfs) which made Kubuntu not bootable anymore the actual system looks normal - there is no "@"-folder. The "@" folder is definitely created by ubiquity - it was not there before installing the second system (standard Ubuntu) - Kubuntu was perfectly usable.

I tried to move all subfolders in "@" back to root folder, but most files from "/@/dev" are not moveable, even with root-privileges.

History of what I did:
At first I did the same thing the other way round, means installing Ubuntu in /dev/sda6, then Kubuntu to /dev/sda7 - resulting in the same strange moving of all files and folders in "/" to "@" - resulting in standard Ubuntu not bootable with "@"-folder, not recognized by grub. From KDE I created another USB-stick with standard Ubuntu, installed it in /dev/sda6 (the actual system) - and now KDE is not bootable because of the "@"-folder. That is the actual situation as I mentioned it in the bug report.

I am quite sure, this behaviour is reproducible on any system. Try to install Ubuntu in one partition, then another install on another partition on the same hd, both btrfs. It is probably reproducible on a virtual machine (I will try that now and let you know the result).

It is not possible to install more than 1 fully working btrfs installation. It's not possible to have more that one 1 @. In total, across all devices attached to the system. This is expected and warned about. More than 1 simultaneous btrfs installation is not supported. If you have enough knowledge to modify grub / initramfs-tools / debian-installer to support this case, such work will be appreciated upstream in Debian and hence in Ubuntu as well.

Oh well, I did not see any warning about this anywhere. Maybe it would be possible to create a message about that in ubiquity when doing manual partitioning and/or when installing into btrfs, that would be very helpful.

I really would like to help out with that issue, but sadly I am no programmer.
I will now install again (*sigh*) on ext4.

Thanks for your help. :)

[Expired for ubiquity (Ubuntu) because there has been no activity for 60 days.]