Bug#976666: perl: perl-modules-5.24 from stretch erroneously satisfies dependencies

[Niko Tyni]

Package: perl
Version: 5.32.0-5
Severity: important
Control: affects -1 liblocale-codes-perl libpod-parser-perl

As seen in #972322 and #975998, we have a problem with perl-modules-5.24
from stretch satisfying dependencies on current sid/bullseye systems.

The perl-modules-5.24 package Provided (among others) liblocale-codes-perl
and libpod-parser-perl, which were moved to separate packages in 5.28
and 5.32 respectively. All the provides entries were moved to perl during
the 5.26 cycle with #899110.

I think we need to make the current perl Break perl-modules-5.24, even
if it would have been nice to keep it coinstallable with later versions.

The coinstallability of libperl* and perl-modules-* is most useful for
oldstable -> stable upgrades, where the old version can be kept around for
a while. This helps at least versioned packages linking against libperl
like postgresql, so the old versions don't get forcibly removed during
the upgrade.

I'm wondering if this needs fixing in buster too, as liblocale-codes-perl
was moved out to a separate package already during the buster cycle.
OTOH the only report we have is about sid/bullseye so it doesn't seem a
very common issue. I'm inclined to skip buster until we get more reports.

Filing a separate bug for clarity; possibly #972322 and #975998 should be
reassigned and merged. I don't think this can be fixed with a source
change on the liblocale-codes-perl / libpod-parser-perl side.

Reverse dependencies of liblocale-codes-perl and libpod-parser-perl could
work around it with a versioned dependency - any version will do as the
stretch Provides were unversioned, but a later version would probably
make sense. This has already been done for gscan2pdf in bullseye.

Not sure if this should be release critical. Filing at 'important' for now.

Eyeballs and comments welcome of course in case I've missed something.
-- 
Niko Tyni   ntyni at debian.org