=encoding utf8

=head1 NAME

perl5439delta - what is new for perl v5.43.9

=head1 DESCRIPTION

This document describes differences between the 5.43.8 release and the 5.43.9
release.

If you are upgrading from an earlier release such as 5.43.7, first read
L<perl5438delta>, which describes differences between 5.43.7 and 5.43.8.

=head1 Core Enhancements

=head2 Enhanced operation of regular expression patterns under /xx

Experimentally, the C</xx> pattern modifier can allow bracketed
character classes (I<e.g.>, C<[a-zA-Z]> to extend across multiple lines
and to contain comments, and to warn you of potential cases where a
portion of a pattern inadvertently has been treated as a comment instead
of what you intended.  This behavior is enabled by S<C<use feature
"enhanced_xx">>.  See L<perlre/E<sol>x and  E<sol>xx>.

=head1 Performance Enhancements

=over 4

=item *

Populating a hash from a list of key/value pairs, when the keys are constant
string operands known at compile time, is commonly now faster. [L<GH #24228|https://github.com/Perl/perl5/issues/24228>]

=back

=head1 Modules and Pragmata

=head2 Updated Modules and Pragmata

=over 4

=item *

L<B> has been upgraded from version 1.91 to 1.92.

=item *

L<Compress::Raw::Bzip2> has been upgraded from version 2.217 to 2.218.

=item *

L<Compress::Raw::Zlib> has been upgraded from version 2.218 to 2.222.

=item *

L<CPAN::Meta> has been upgraded from version 2.150012 to 2.150013.

=item *

L<CPAN::Meta::Requirements> has been upgraded from version 2.143 to 2.145.

=item *

L<ExtUtils::CBuilder> has been upgraded from version 0.280242 to 0.280243.

=item *

L<ExtUtils::MakeMaker> has been upgraded from version 7.76 to 7.78.

=item *

L<feature> has been upgraded from version 2.01 to 2.02.

=item *

L<File::Glob> has been upgraded from version 1.42 to 1.43.

=item *

L<File::Spec> has been upgraded from version 3.94 to 3.95.

=item *

L<IO> has been upgraded from version 1.55 to 1.56.

=item *

L<IO::Compress> has been upgraded from version 2.217 to 2.219.

=item *

L<Module::CoreList> has been upgraded from version 5.20260220 to 5.20260320.

=item *

L<Opcode> has been upgraded from version 1.70 to 1.71.

=item *

L<POSIX> has been upgraded from version 2.25 to 2.26.

=item *

L<Storable> has been upgraded from version 3.39 to 3.40.

=item *

L<threads> has been upgraded from version 2.44 to 2.45.

=item *

L<threads::shared> has been upgraded from version 1.72 to 1.73.

=item *

L<warnings> has been upgraded from version 1.77 to 1.78.

=item *

L<XS::APItest> has been upgraded from version 1.49 to 1.50.

=back

=head1 Internal Changes

=over 4

=item *

Dedicated check functions C<Perl_ck_anonhash> and C<Perl_ck_aassign> have been
added and are used to hekify some C<OP_CONST> hash keys at compile time.
[L<GH #24228|https://github.com/Perl/perl5/issues/24228>]

=item *

C<Perl_check_hash_fields_and_hekify>, partly called as a compile-time
optimization, no longer preemptively converts an NV to a HEK if the
compile time and run time locales could differ.
[L<GH #24252|https://github.com/Perl/perl5/issues/24252>]

=item *

C<Perl_check_hash_fields_and_hekify>, partly called as a compile-time
optimization, no longer preemptively converts a UTF-8 string to a HEK
when this will downgrade the string to a single byte representation.

At present, multiple functions inadequately handle the flag used to
denote when a key originally had UTF-8 encoding, making it impossible to
restore the encoding when keys are extracted from a hash (using C<keys>
for example).

Tracking of UTF-8 origins can hopefully be improved in the next development
cycle, allowing for preemptive conversion of all UTF-8 strings once again.
[L<GH #24266|https://github.com/Perl/perl5/issues/24266>]
[L<GH #24287|https://github.com/Perl/perl5/issues/24287>]

=item *

The macro L<perlapi/C<fromCTRL>> has been added to be the inverse of the
existing L<perlapi/C<toCTRL>>.  C<toCTRL('A')> yields 1 (the control
character C<SOH> on all platforms Perl works on); C<fromCTRL(1)>
yields 'A'.

=back

=head1 Selected Bug Fixes

=over 4

=item *

On debugging perls, instantiating a class with an array field with an empty
initializer list would abort with an error:

    class Foo {
        field @bar = ();
    }
    Foo->new();

Error message: C<< perl: inline.h:194: Perl_av_new_alloc: Assertion `size > 0'
failed. >>

This has been fixed. [L<GH #24246|https://github.com/Perl/perl5/issues/24246>]

=item *

Refassigning to a class field in a method could result in the SV for
that field being released when the method exited.  The next access to
that field could result in a crash or an assertion, or if the freed SV
had been re-used, random data.  Discussed in [L<GH #24187|https://github.com/Perl/perl5/issues/24187>]

=back

=head1 Acknowledgements

Perl 5.43.9 represents approximately 4 weeks of development since Perl
5.43.8 and contains approximately 14,000 lines of changes across 310 files
from 22 authors.

Excluding auto-generated files, documentation and release tools, there were
approximately 9,500 lines of changes to 230 .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 5.43.9:

Chris 'BinGOs' Williams, Craig A. Berry, Dagfinn Ilmari Mannsåker, David
Mitchell, Ed J, Eric Herman, Graham Knop, Harald Jörg, James E Keenan, Karl
Williamson, Leon Timmermans, Lukas Mai, Olaf Alders, Paul Evans, Paul
Marquess, Ricardo Signes, Richard Leach, Scott Baker, Sevan Janiyan, Steve
Hay, Toby Inkster, Tony Cook.

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
