PERL5421DELTA(1)

NAME
perl5421delta - what is new for perl v5.42.1

DESCRIPTION
This document describes differences between the 5.42.0 release and the 5.42.1 release.

If you are upgrading from an earlier release such as 5.40.0, first read perl5420delta, which describes differences between 5.40.0 and 5.42.0.

Incompatible Changes
There are no changes intentionally incompatible with Perl 5.42.0. If any exist, they are bugs, and we request that you submit a report. See "Reporting Bugs" below.

Modules and Pragmata

  Updated Modules and Pragmata

•   Module::CoreList has been upgraded from version 5.20250702 to 5.20260308.

•   POSIX has been upgraded from version 2.23 to 2.23_01.

Documentation

  Changes to Existing Documentation
We have attempted to update the documentation to reflect the changes listed in this document. If you find any we have missed, open an issue at <https://github.com/Perl/perl5/issues>.

Configuration and Compilation

•   It is now possible to pass to Configure the values dealing with POSIX locale categories, overriding its automatic calculation of these. This enables cross-compilation to work. The easiest way to do this is to extract the C program that does the calculation from Configure and then run it on the target machine, and then pass the values it outputs to Configure on the other machine. Porting/Glossary has examples. [GH #22992 <https://github.com/Perl/perl5/issues/22992>]

Testing
Tests were added and changed to reflect the other additions and changes in this release.

Platform Support

  Platform-Specific Notes

AIX Thread-safe locale handling has been turned off on all releases due to apparent bugs in the underlying operating system support. [GH #23825 <https://github.com/Perl/perl5/issues/23825>]

Win32
    Fix builds with "USE_IMP_SYS" defined but "USE_ITHREADS" not defined.

Selected Bug Fixes

•   "use 5.42" now turns on "use source::encoding "ascii"" for the remainder of the line (besides subsequent lines). [GH #23881 <https://github.com/Perl/perl5/issues/23881>]

•   Perl 5.42.0 does not handle the transition to/from daylight savings time properly. The time and/or timezone can be off by an hour in the intervals surrounding such transitions. This is a regression from earlier releases, and is now fixed. This bug was evident from perl space in the "strftime" in POSIX function, and in XS code with any of "my_strftime" in perlapi, "sv_strftime_ints" in perlapi, or "sv_strftime_tm" in perlapi. [GH #23878 <https://github.com/Perl/perl5/issues/23878>]

•   Certain constructs involving a two-variable "for" loop would crash the perl compiler in Perl 5.42.0:

        # Two-variable for loop over a list returned from a method call:
        for my ($x, $y) (Some::Class->foo()) { ... }
        for my ($x, $y) ($object->foo()) { ... }

    and

        # Two-variable for loop over a list returned from a call to a
        # lexical(ly imported) subroutine, all inside a lexically scoped
        # or anonymous subroutine:
        my sub foo { ... }
        my $fn = sub {
            for my ($x, $y) (foo()) { ... }
        };

        use builtin qw(indexed);  # lexical import!
        my sub bar {
            for my ($x, $y) (indexed(...)) { ... }
        }

    These have been fixed. [GH #23405 <https://github.com/Perl/perl5/issues/23405>]

•   Since Perl 5.32.0, the second branch of a ternary condition operator wasn't getting the correct autovivification context applied. For example in something like

        @{ $cond ? $h{foo} : $h{bar} } = ...;

    the first branch would correctly autovivify $h{foo} to an array ref, but the second branch might incorrectly autovivify $h{bar} to a hash ref. [GH #18669 <https://github.com/Perl/perl5/issues/18669>].

Acknowledgements
Perl 5.42.1 represents approximately 8 months of development since Perl 5.42.0 and contains approximately 7,200 lines of changes across 55 files from 12 authors.

Excluding auto-generated files, documentation and release tools, there were approximately 1,700 lines of changes to 16 .pm, .t, .c and .h files.

Perl continues to flourish into its fourth decade thanks to a vibrant community of users and developers. The following people are known to have contributed the improvements that became Perl 5.42.1:

David Mitchell, Eric Herman, Karen Etheridge, Karl Williamson, Lukas Mai, Max Maischein, Philippe Bruhat (BooK), Richard Leach, Steve Hay, Thibault Duponchelle, Tony Cook, Yitzchak Scott-Thoennes.

The list above is almost certainly incomplete as it is automatically generated from version control history. In particular, it does not include the names of the (very much appreciated) contributors who reported issues to the Perl bug tracker.

Many of the changes included in this version originated in the CPAN modules included in Perl's core. We're grateful to the entire CPAN community for helping Perl to flourish.

For a more complete list of all of Perl's historical contributors, please see the AUTHORS file in the Perl source distribution.

Reporting Bugs
If you find what you think is a bug, you might check the perl bug database at <https://github.com/Perl/perl5/issues>. There may also be information at <https://www.perl.org/>, the Perl Home Page.

If you believe you have an unreported bug, please open an issue at <https://github.com/Perl/perl5/issues>. Be sure to trim your bug down to a tiny but sufficient test case.

If the bug you are reporting has security implications which make it inappropriate to send to a public issue tracker, then see "SECURITY VULNERABILITY CONTACT INFORMATION" in perlsec for details of how to report the issue.

Give Thanks
If you wish to thank the Perl 5 Porters for the work we had done in Perl 5, you can do so by running the "perlthanks" program:

    perlthanks

This will send an email to the Perl 5 Porters list with your show of thanks.

SEE ALSO
The Changes file for an explanation of how to view exhaustive details on what changed.

The INSTALL file for how to build Perl.

The README file for general stuff.

The Artistic and Copying files for copyright information.