=encoding utf8

=head1 NAME

perldelta - what is new for perl v5.39.10

=head1 DESCRIPTION

This document describes differences between the 5.39.9 release and the 5.39.10
release.

If you are upgrading from an earlier release such as 5.39.8, first read
L<perl5399delta>, which describes differences between 5.39.8 and 5.39.9.

=head1 Core Enhancements

=head2 The C<:5.40> feature bundle adds C<try> and C<extra_paired_delimiters>

The latest version feature bundle now contains the recently-stablized features
C<try> and C<extra_paired_delimiters>. As this feature bundle is used by the
C<-E> commandline switch, these are immediately available in C<-E> scripts.

=head1 Modules and Pragmata

=head2 Updated Modules and Pragmata

=over 4

=item *

L<B::Deparse> has been upgraded from version 1.75 to 1.76.

=item *

L<Compress::Raw::Bzip2> has been upgraded from version 2.210 to 2.212.

=item *

L<Compress::Raw::Zlib> has been upgraded from version 2.209 to 2.212.

=item *

L<experimental> has been upgraded from version 0.031 to 0.032.

=item *

L<feature> has been upgraded from version 1.86 to 1.88.

=item *

L<IO::Compress> has been upgraded from version 2.207 to 2.212.

=item *

L<locale> has been upgraded from version 1.11 to 1.12.

=item *

L<Module::CoreList> has been upgraded from version 5.20240320 to 5.20240420.

=item *

L<podlators> has been upgraded from version 5.01 to 5.01_01.

=item *

L<POSIX> has been upgraded from version 2.18 to 2.19.

=item *

L<Socket> has been upgraded from version 2.037 to 2.038.

=item *

L<Test2::Suite> has been upgraded from version 0.000159 to 0.000162.

=item *

L<Test::Simple> has been upgraded from version 1.302198 to 1.302199.

=item *

L<warnings> has been upgraded from version 1.68 to 1.69.

=item *

L<XS::APItest> has been upgraded from version 1.35 to 1.36.

=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>.

Additionally, the following selected changes have been made:

=head3 L<perlhacktips>

=over 4

=item *

Added brief documentation for some tools useful when developing perl
itself on Windows or Cygwin.

=back

=head1 Diagnostics

The following additions or changes have been made to diagnostic output,
including warnings and fatal error messages.  For the complete list of
diagnostic messages, see L<perldiag>.

=head2 New Diagnostics

=head3 New Errors

=over 4

=item *

L<Cannot create an object of incomplete class "%s"|perldiag/"Cannot create an object of incomplete class "%s"">

(F) An attempt was made to create an object of a class where the start
of the class definition has been seen, but the class has not been
completed.

This can happen for a failed eval, or if you attempt to create an
object at compile time before the class is complete:

  eval "class Foo {"; Foo->new; # error
  class Bar { BEGIN { Bar->new } }; # error

Previously perl would assert or crash. [L<github #22159|https://github.com/Perl/perl5/issues/22159>]

=back

=head2 Changes to Existing Diagnostics

=over 4

=item *

L<Old package separator "'" deprecated|perldiag/"Old package separator "'" deprecated">

Prevent this warning appearing spuriously when checking the heuristic for the
L<You need to quote "%s"|perldiag/"You need to quote "%s""> warning.

[L<github #22145|https://github.com/Perl/perl5/issues/22145>]

=back

=head1 Configuration and Compilation

=over 4

=item *

You can now separately enable high water mark checks for non-DEBUGGING
or disable them for DEBUGGING builds with C<-Accflags=-DPERL_USE_HWM>
or C<-Accflags=-DPERL_NO_HWM> respectively.  The default remains the
same.  [L<github #16607|https://github.com/Perl/perl5/issues/16607>]

=back

=head1 Selected Bug Fixes

=over 4

=item *

prepare_export_lexical() was separately saving C<PL_comppad> and
C<PL_curpad>, this could result in C<PL_curpad> being restored to a no
longer valid value, resulting in a panic when importing lexicals in
some cases.  [L<github #21981|https://github.com/Perl/perl5/issues/21981>]

=item *

A string eval() operation in the scope of a C<use VERSION> declaration would
sometimes emit spurious "Changing use VERSION" warnings due to an
inconsistency in the way the version number was stored.  This is now fixed.
[L<github #22121|https://github.com/Perl/perl5/issues/22121>]

=back

=head1 Known Problems

=over 4

=item *

fork() failures on cygwin with C<-DDEBUGGING> builds.

Perl uses the C<--enable-auto-image-base> option to set the base
images for DLLs for C<cygperl5_39_10.dll> and the DLLs needed for
dynamically loaded modules on cygwin.

With 5.39.10 if perl is built with C<-DDEBUGGING> or possibly other
options that increase the address space used by F<cygperl5_39_10.dll>,
the address space for F<cygperl5_39_10.dll> overlaps with the address
space allocated for F<mro.dll>.

The C<mro> module will still load, but if perl attempts to fork you
will likely see an error like:

 0 [main] perl 34054 child_info_fork::abort: address space needed by \
    'mro.dll' (0x400000) is already occupied

You can workaround this by building without the C<-DDEBUGGING> option,
or by making C<mro> a static extension:

  ./Configure ... -Astatic_ext=mro

We expect the name change of the F<cygperl5_39_10.dll> to
F<cygperl5_39_11.dll> in 5.39.11 will fix this problem for the next
release.  [L<github #22104|https://github.com/Perl/perl5/issues/22104>]

=back

=head1 Acknowledgements

Perl 5.39.10 represents approximately 5 weeks of development since Perl
5.39.9 and contains approximately 7,000 lines of changes across 380 files
from 15 authors.

Excluding auto-generated files, documentation and release tools, there were
approximately 4,300 lines of changes to 320 .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 5.39.10:

Bernard Quatermass, Craig A. Berry, Dagfinn Ilmari Mannsåker, David
Mitchell, Elvin Aslanov, Graham Knop, H.Merijn Brand, James E Keenan, Karl
Williamson, Lukas Mai, Paul Evans, TAKAI Kousuke, Tomasz Konojacki, Tony
Cook, Yves Orton.

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