Bug#987615: perl-base: please ship modules used by usrmerge in perl-base

[Niko Tyni]

On Mon, Apr 26, 2021 at 03:26:02PM +0100, Dimitri John Ledkov wrote:
> Package: perl-base
> Version: 5.30.3-4
> Severity: normal
> 
> Dear Maintainer,
> 
> usrmerge will be needed to be installed upon upgrades to bookworm to
> convert systems to merged /usr. It would be helpful for small installs
> to be able to perform that without installing the larger perl package.

Thanks for raising this early. I'm copying the usrmerge maintainer.
 
> Please consider moving things that usrmerge & libfile-find-rule-perl
> use from per/perl-modules to perl-base.

I understand the concern, but I'm hesitant to do this. See below.

> In bookworm+1 you may drop these things from perl-base and add breaks
> on usrmerge.

Quoting the Debian policy:

  Maintainers should take great care in adding any programs, interfaces,
  or functionality to essential packages. Packages may assume that
  functionality provided by essential packages is always available without
  declaring explicit dependencies, which means that removing functionality
  from the Essential set is very difficult and is almost never done. Any
  capability added to an essential package therefore creates an obligation
  to support that capability as part of the Essential set in perpetuity.

Have other avenues been investigated? How critical is the
libfile-find-rule-perl dependency - would it be hard to replace it with
something that's already in the Essential set, for instance piping from
find(1) ? Could autodie usage be replaced with explicit error handling?

Is Perl the right language to implement the migration in the first
place? A small binary with minimal external dependencies would seem
preferable.

-- 
Niko Tyni   ntyni at debian.org