Move AutoLoader distribution to 'dist/'

[jkeenan]

As discussed in #15866 (comment), we plan (at some date TBD) to move the code for AutoLoader to be fully "blead-upstream." Currently the code resides under the cpan/ directory within the core distribution; that would imply that the code is maintained "cpan-upstream." It turns out that that has never been the case. From the documentation to lib/AutoSplit.pm we see:

This package has been part of the perl core since the first release
of perl5. It has been released separately to CPAN so older installations
can benefit from bug fixes.

So AutoLoader's code should have been moved to reside under dist/ years ago. Moreover, its CPAN release contains no separate repository information, so there's probably no version control history that we need to retain.

This ticket exists to track that correction. We need to:

1. Move the AutoLoader distribution from cpan/ to dist/.
2. Review the code -- particularly with respect to operating systems we no longer support -- and its test coverage.
3. Address the issue originally raised in AutoLoader implies suitability for constants, fails to mention inlining incompatibility [patch] #15866: "AutoLoader implies suitability for constants, fails to mention inlining incompability". Evaluate the patch submitted therein.
4. Evaluate the sole remaining bug report in RT: https://rt.cpan.org/Ticket/Display.html?id=45679
5. Recruit someone to be the releasor of AutoLoader to CPAN (assuming we're going to maintain compatibility with older perls).

Thank you very much.
Jim Keenan

[toddr]

I've set a milestone for 5.33.1 so we can track the needed work deadline.

[jkeenan]

A first draft of the transfer can be found in this branch: ghi-17707-autoloader.

There is one documentation problem which will have to be addressed. As a dual-life module, AutoLoader was built to accommodate very early versions of perl. There is a paragraph in the documentation which refers to the use vars pragma, which has been discouraged since the introduction of our variables in perl-5.6 and which has, to a great extent, been purged from the core distribution as of 5.28. (I only discovered this paragraph by running t/porting/podcheck.t, which flagged a no-longer-valid hyperlink.) We'll have to decide how to modify the docs such that they make sense when dual-released to CPAN.

[toddr]

https://github.com/Perl/perl5/tree/ghi-17707-autoloader

[jkeenan]

Since perl-5.33.0 has been released, we can now commence work on tickets labelled with the 5.33.1 milestone.

In #15866 (comment), @xsawyerx okayed bringing this distribution into maintenance by Perl core developers, i.e., moving its location within the core distribution from cpan/ to dist/. I outlined above the steps that would be needed to make this happen.

This might be a good "first project" for someone. Anyone want to step forward?

Thank you very much.
Jim Keenan

[Leont]

This might be a good "first project" for someone. Anyone want to step forward?

Yes and no.

They can be entirely new to core work, but they should be familiar with doing CPAN releases (fortunately, that pool is fairly big). And they should be able to commit to managing this, we don't need any more dual-life maintainers who go MIA after a year.