Bug#721390: libxml-libxml-perl: errors on upgrade

[Niko Tyni]

On Sat, Aug 31, 2013 at 02:50:29AM +0200, Christoph Anton Mitterer wrote:
> Package: libxml-libxml-perl
> Version: 2.0010+dfsg-1+b1
> Severity: normal

> These errors appeared on upgrading:
> Preparing to replace libxml-libxml-perl 2.0010+dfsg-1 (using .../libxml-libxml-perl_2.0010+dfsg-1+b1_amd64.deb) ...
> Can't locate File/Basename.pm in @INC (you may need to install the File::Basename module) (@INC contains: /etc/perl /usr/local/lib/perl/5.18.1 /usr/local/share/perl/5.18.1 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.18 /usr/share/perl/5.18 /usr/local/lib/site_perl .) at /usr/share/perl5/XML/SAX.pm line 15.
> BEGIN failed--compilation aborted at /usr/share/perl5/XML/SAX.pm line 15.
> Compilation failed in require at /usr/bin/update-perl-sax-parsers line 18.
> BEGIN failed--compilation aborted at /usr/bin/update-perl-sax-parsers line 18.
> dpkg: warning: subprocess old pre-removal script returned error exit status 2
> dpkg: trying script from the new package instead ...
> dpkg: ... it looks like that went OK

The issue is 'old-prerm upgrade' relying on non-essential functionality.
I don't think it is explicitly spelled out in the policy, but in practice
it just doesn't work.

However, I believe this case is mostly cosmetic as 'new-prerm
failed-upgrade old-version' succeeds so the upgrade doesn't break.
It's possible that the resulting list of SAX parsers is not quite right,
but IIRC I tested this at some point and didn't see any serious breakage.

The situation around update-perl-sax-parsers is clearly a mess, and I
think we have accumulated quite a few other related bugs over the years.
While I do feel some guilt over my involvement in the setup, I sorely
lack the motivation to properly fix it myself.
-- 
Niko Tyni   ntyni at debian.org