Dependency hell: Conflicting library is known to dpkg...

[nigratruo]

I'm in hell after upgrading a debian 8 to 9 and can't get out. Terrible, have been running in circles for hours and was wondering if anybody knows what the hell this means "dpkg knows about this conflict".... and??? Does this mean is knows how to resolve it? Or KNEW about it or what? Can't find any documentation about this. I also don't understand what diversions are and why I need them (would love to get rid of them, they are just a huge problem and the source of several bugs)

Setting up libgl1-nvidia-legacy-340xx-glx:i386 (340.102-1) ...
ERROR: The conflicting library '/usr/lib/x86_64-linux-gnu/libGL.so.1.2.0' is known to dpkg.
diversion by glx-diversions from: /usr/lib/x86_64-linux-gnu/libGL.so.1.2.0
diversion by glx-diversions to: /usr/lib/mesa-diverted/x86_64-linux-gnu/libGL.so.1.2.0
libgl1-mesa-glx:amd64: /usr/lib/x86_64-linux-gnu/libGL.so.1.2.0

Any pointers how to escape hell would be appreciated.

Thanks,

Markus

[kedaha]

My advice would be to purge the system of all the non-free nvidia packages and proceed with the upgrade this avoiding the hellish conflicting libary.
Since, by the looks of it, it's a legacy card the nouveau driver can be used.

[nigratruo]

Sadly, it cannot, I have a clear and pressing reason why I have to use the proprietary driver, otherwise I will not be able to use this otherwise fully functional laptop anymore:

http://www.linuxquestions.org/questions ... page3.html

This kernel bug still exists in 4.9.30-2+deb9u3, so no dice using nouveau.

[kedaha]

I did a search and came up with nvidia-glx-amd64-wont-upgrade-due-to-conflicting-library, which I think may help you to solve your problem when "the conflicting library is known to dpkg" and thus get out of "dependency hell."

[nigratruo]

I solved it, I just renamed the file that dpkg was complaining about. Then, when trying to remove it, the nvidia cleanup package said that it found left overs from a former nvidia package install and offered to remove it, which solved the problem.

[kedaha]

Well done! You persevered with it.

"[...]what the hell this means "dpkg knows about this conflict".... and??? Does this mean is knows how to resolve it? Or KNEW about it or what?"

So the leftovers were from a previous driver installation with the nvidia-installer. You should've said this; of course it conflicts with the packaged nvidia drivers.
As for documentation, the man page for dpkg answers your questions:
dpkg can remove Debian packages but it cannot remove packages which it has played no part in installing through the front-end aptitude or apt. So it was not a question of "dependency hell" or "several bugs" at all. But anyway, using the nvidia-installer-cleanup package was your salvation from going round in circles in hell. "It does what it says on the tin," i.e., it cleans up the infernal mess left by the nvidia-installer.