Re: WARNING! New Perl/Perl-base upgrade removes 141 Sid/Unstable packages

[Christian Seiler <christian@iwakd.de>]

On 09/24/2016 06:02 PM, Glenn English wrote:
>> On Sep 24, 2016, at 7:44 AM, rhkramer@gmail.com wrote:
>>
>> For my own education, I'm not sure what you mean by "backup your current state
>> before upgrading"--does that mean a full backup of your system, or is there a 
>> way to somehow save the current "state" of the package list on your system so 
>> that you can easily request those packages be restored if something goes 
>> wrong?
> 
> I think that saving the contents of /var/cache/apt/archive(s?) will
> save copies of all the .debs installed on your machine. OTOH, it also
> gets .debs that *used* to be on your machine. If you're running sid,
> bring a big thumbdrive...

Note that the new apt wrapper removes .debs after installation by
default. (apt-get and aptitude will keep the .deb files though.)

So if you use

apt install foo

or

apt upgrade

then the packages that were downloaded won't be there after the
installation completed successfully. (They will be in the cache
directory after download and before the installation is done.)

You can change that behavior via:

echo 'Binary::apt::APT::Keep-Downloaded-Packages "true";' \
      > /etc/apt/apt.conf.d/01keep-debs

(See also /usr/share/doc/apt/NEWS.Debian.gz for details.)

Regarding the original problem: I'd recommend to anyone running
sid to also have testing in their sources.list - so they can
force the installation of an older package version while a
transition is still ongoing. Also, it's IMHO a good idea to
subscribe to debian-release for anyone running pure sid, so they
can have an overview over currently active transitions.

Regards,
Christian