=encoding utf8

=head1 NAME

perl5421delta - what is new for perl v5.42.1

=head1 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
L<perl5420delta>, which describes differences between 5.40.0 and 5.42.0.

=head1 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
L</Reporting Bugs> below.

=head1 Modules and Pragmata

=head2 Updated Modules and Pragmata

=over 4

=item *

L<Module::CoreList> has been upgraded from version 5.20250702 to 5.20260308.

=item *

L<POSIX> has been upgraded from version 2.23 to 2.23_01.

=back

=head1 Documentation

=head2 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
L<https://github.com/Perl/perl5/issues>.

=head1 Configuration and Compilation

=over 4

=item *

It is now possible to pass to F<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 F<Configure> and then run it on the
target machine, and then pass the values it outputs to F<Configure> on the
other machine.  F<Porting/Glossary> has examples.
[L<GH #22992|https://github.com/Perl/perl5/issues/22992>]

=back

=head1 Testing

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

=head1 Platform Support

=head2 Platform-Specific Notes

=over 4

=item AIX

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

=item Win32

Fix builds with C<USE_IMP_SYS> defined but C<USE_ITHREADS> not defined.

=back

=head1 Selected Bug Fixes

=over 4

=item *

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

=item *

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 L<POSIX/strftime>
function, and in XS code with any of L<perlapi/my_strftime>,
L<perlapi/sv_strftime_ints>, or L<perlapi/sv_strftime_tm>.
[L<GH #23878|https://github.com/Perl/perl5/issues/23878>]

=item *

Certain constructs involving a two-variable C<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.
[L<GH #23405|https://github.com/Perl/perl5/issues/23405>]

=item *

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

=back

=head1 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 F<AUTHORS> file in the Perl source distribution.

=head1 Reporting Bugs

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

If you believe you have an unreported bug, please open an issue at
L<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
L<perlsec/SECURITY VULNERABILITY CONTACT INFORMATION> for details of how to
report the issue.

=head1 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 C<perlthanks> program:

    perlthanks

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

=head1 SEE ALSO

The F<Changes> file for an explanation of how to view exhaustive details on
what changed.

The F<INSTALL> file for how to build Perl.

The F<README> file for general stuff.

The F<Artistic> and F<Copying> files for copyright information.

=cut