Bug#838760: perl: Perl/Perl-base upgrade removes 141 packages (Sid/Unstable)

[Russ Allbery]

Cindy Sue Causey <ButterflyBytes at gmail.com> writes:

> Hi! Thank you for all the hard work you all to so #poverty level folks
> have a chance to keep up with the tech world, too! As to why I'm
> writing, just tried to upgrade a select 30+ packages in
> Sid/Unstable. Apt-get is my chosen method to do so. Received the message
> that Received the advisement that:

> 2 upgraded, 2 newly installed, 141 to remove

> ALMOST let it happen because I was in a hurry and didn't immediately
> catch that message. Only thing I know to do in this kind of situation is
> to set Perl and Perl-base aside and wait for the next release so that's
> how I'm approaching it today.

For future reference, you get results like this mostly from apt-get
install of specific packages, since then apt-get goes to considerably more
lengths to try to do what you're telling it to do (including contemplating
removing temporarily conflicting packages).

If instead you do a whole-system upgrade with apt-get upgrade, you'll see
all these packages will just be held back until they can be safely
upgraded.  Even if you use the more aggressive apt-get dist-upgrade, right
now you get something (depending on the packages you have installed) like:

# apt dist-upgrade
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Calculating upgrade... Error!
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 libenchant1c2a : Depends: aspell-en but it is not going to be installed or
                           myspell-dictionary or
                           aspell-dictionary or
                           ispell-dictionary or
                           hunspell-dictionary
E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.

which is not horribly informative but at least doesn't do the wrong thing.

You probably have reasons to want to upgrade specific packages instead of
your system in better, but it's worth being aware that this is one case
where this can be less safe (if you don't watch apt-get closely) than
letting it use its normal upgrade semantics.  (Also, a general upgrade is
safer in that you'll always get security updates.)

-- 
Russ Allbery (rra at debian.org)               <http://www.eyrie.org/~eagle/>