Bug#1019757: perl: Subroutine JSON::PP::Boolean::(-- redefined with 5.36

[Niko Tyni]

Package: perl
Version: 5.36.0-2
User: debian-perl at lists.debian.org
Usertags: perl-5.36-transition
Forwarded: https://github.com/Perl/perl5/issues/20246
X-Debbugs-Cc: libmetacpan-client-perl at packages.debian.org
Control: affects -1 libmetacpan-client-perl
Control: block 1019353 with -1

This warns with Perl >= 5.36:

  % perl -we 'use Cpanel::JSON::XS (); use JSON::PP'
  Subroutine JSON::PP::Boolean::(0+ redefined at /usr/lib/x86_64-linux-gnu/perl-base/overload.pm line 52.
  Subroutine JSON::PP::Boolean::(++ redefined at /usr/lib/x86_64-linux-gnu/perl-base/overload.pm line 52.
  Subroutine JSON::PP::Boolean::(-- redefined at /usr/lib/x86_64-linux-gnu/perl-base/overload.pm line 52.

I have filed https://github.com/makamaka/JSON-PP/issues/76 against
JSON::PP about this, but it's currently unclear if it should rather be
"fixed" on the Perl side ( https://github.com/Perl/perl5/issues/20246 ).

The immediate impact is that (at least) libmetacpan-client-perl now
fails its autopkgtest checks because of the warning, as seen at

  https://ci.debian.net/data/autopkgtest/unstable/amd64/libm/libmetacpan-client-perl/26050668/log.gz

  #   Failed test ' /usr/bin/perl -w -M"MetaCPAN::Client" -e 1 2>&1 produced no (non-whitelisted) output'
  #   at /usr/share/pkg-perl-autopkgtest/runtime-deps.d/use.t line 110.
  #     Structures begin differing at:
  #          $got->[0] = 'Subroutine JSON::PP::Boolean::(-- redefined at /usr/lib/x86_64-linux-gnu/perl-base/overload.pm line 52.
  #     '
  #     $expected->[0] = Does not exist

and verified manually:

  % perl -we 'use MetaCPAN::Client'
  Subroutine JSON::PP::Boolean::(0+ redefined at /usr/lib/x86_64-linux-gnu/perl-base/overload.pm line 52.
  Subroutine JSON::PP::Boolean::(-- redefined at /usr/lib/x86_64-linux-gnu/perl-base/overload.pm line 52.
  Subroutine JSON::PP::Boolean::(++ redefined at /usr/lib/x86_64-linux-gnu/perl-base/overload.pm line 52.


This didn't happen in my earlier tests with 5.36 so the failure is
probably rather sensitive to changes in the dependency chain.

Not sure yet what to do about this but it doesn't feel like it should
be a hard blocker for the Perl 5.36 transition. Adding the metadata for
now anyway so we don't forget about it.
-- 
Niko Tyni   ntyni at debian.org