Bug#543910: perl: CPANPLUS config file change may lose local configuration on upgrades

[Niko Tyni]

Package: perl
Version: 5.10.0-24
Severity: important

The CPANPLUS configuration changes introduced in 5.10.0-24 (see #533707)
may lose local configuration on upgrades if root has done a 's save system'
in the cpanp shell on earlier versions.

The settings used to be saved to
/usr/share/perl/5.10/CPANPLUS/Config/System.pm but this file is shipped
in perl-modules from 5.10.0-24 onwards, overwriting the saved settings.

This is bordering on RC severity but mitigated a bit by the fact that
cpanp outputs the full path when saving the settings:

 CPAN Terminal> s save system

 Configuration successfully saved to CPANPLUS::Config::System
     (/usr/share/perl/5.10/CPANPLUS/Config/System.pm)

An observant user might notice that there's something wrong here.


I think this needs to be fixed by checking for an existing
/usr/share/perl/5.10/CPANPLUS/Config/System.pm in the preinst and copying
that into /etc/perl (if there isn't another copy there already, of course).

Additionally, an md5sum check for the known version of the file we ship
with 5.10.0-24 would probably be a good idea.

I was going to include the CPANPLUS changes in the stable update I'm preparing,
but this means I will at least defer them for a later one.
-- 
Niko Tyni   ntyni at debian.org