=encoding utf8

=head1 NAME

perl5313delta - what is new for perl v5.31.3

=head1 DESCRIPTION

This document describes differences between the 5.31.2 release and the 5.31.3
release.

If you are upgrading from an earlier release such as 5.31.1, first read
L<perl5312delta>, which describes differences between 5.31.1 and 5.31.2.

=head1 Incompatible Changes

=head2 Plain "0" string now treated as a number for range operator

Previously a range C< "0" .. "-1" > would produce a range of numeric
strings from "0" through "99", this now produces an empty list, just
as C< 0 .. -1 > does.

This was due to a special case that treated strings starting with "0"
as strings so ranges like C< "00" .. "03" > produced C< "00", "01",
"02", "03" >, but didn't specially handle the string C<"0">.

[perl #133695]

=head2 C<\K> now disallowed in look-ahead and look-behind assertions

This was disallowed because it causes unexpected behaviour, and no-one
could define what the desired behaviour was.

[perl #124256]

=head1 Modules and Pragmata

=head2 Updated Modules and Pragmata

=over 4

=item *

L<Compress::Raw::Bzip2> has been upgraded from version 2.086 to 2.087.

=item *

L<Compress::Raw::Zlib> has been upgraded from version 2.086 to 2.087.

=item *

L<Devel::PPPort> has been upgraded from version 3.54 to 3.55.

The test files generated on Win32 are now identical to when they are
generated on POSIX-like systems.

=item *

L<File::Find> has been upgraded from version 1.36 to 1.37.

On Win32, the tests no longer require either a file in the drive root
directory, or a writable root directory.

=item *

L<Getopt::Long> has been upgraded from version 2.50 to 2.51.

=item *

L<I18N::LangTags> has been upgraded from version 1.07 to 1.08.

Document the C<IGNORE_WIN32_LOCALE> environment variable.

=item *

L<IO::Compress> has been upgraded from version 2.086 to 2.087.

=item *

L<Module::CoreList> has been upgraded from version 5.20190720 to 5.20190820.

=item *

L<PerlIO::via> has been upgraded from version 0.17 to 0.18.

=item *

L<Storable> has been upgraded from version 3.16 to 3.17.

=item *

L<Test::Simple> has been upgraded from version 1.302164 to 1.302166.

=item *

L<Thread> has been upgraded from version 3.04 to 3.05.

=item *

L<Time::HiRes> has been upgraded from version 1.9761 to 1.9762.

Removed obsolete code such as support for pre-5.6 perl and classic
MacOS.  [perl #134288]

=item *

L<Win32> has been upgraded from version 0.52 to 0.53.

=item *

L<XS::APItest> has been upgraded from version 1.01 to 1.02.

=back

=head1 Platform Support

=head2 Platform-Specific Notes

=over 4

=item Windows

F<t/op/magic.t> could fail if environment varables starting with
C<FOO> already existed.

=back

=head1 Internal Changes

=over 4

=item *

A new parser function L<parse_subsignature()|perlapi/parse_subsignature>
allows a keyword plugin to parse a subroutine signature while C<use feature
'signatures'> is in effect.  This allows custom keywords to implement
semantics similar to regular C<sub> declarations that include signatures.
[perl #132474]

=item *

Since on some platforms we need to hold a mutex when temporarily
switching locales, new macros (C<STORE_LC_NUMERIC_SET_TO_NEEDED_IN>,
C<WITH_LC_NUMERIC_SET_TO_NEEDED> and C<WITH_LC_NUMERIC_SET_TO_NEEDED_IN>)
have been added to make it easier to do this safely and efficiently
as part of [perl #134172].

=item *

The memory bookkeeping overhead for allocating an OP structure has been
reduced by 8 bytes per OP on 64-bit systems.

=back

=head1 Selected Bug Fixes

=over 4

=item *

C<< $@ = 100; die; >> now correctly propagates the 100 as an exception
instead of ignoring it.  [perl #134291]

=item *

C<< 0 0x@ >> no longer asserts in S_no_op().  [perl #134310]

=item *

Exceptions thrown while C<$@> is read-only could result in infinite
recursion as perl tried to update C<$@>, which throws another
exception, resulting in a stack overflow.  Perl now replaces C<$@>
with a copy if it's not a simple writable SV.  [perl #134266]

=back

=head1 Acknowledgements

Perl 5.31.3 represents approximately 4 weeks of development since Perl
5.31.2 and contains approximately 9,900 lines of changes across 230 files
from 23 authors.

Excluding auto-generated files, documentation and release tools, there were
approximately 2,800 lines of changes to 160 .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 5.31.3:

Alexandr Savca, Andrew Fresh, Chad Granum, Chris 'BinGOs' Williams, Dagfinn
Ilmari Mannsåker, Dan Book, David Cantrell, David Mitchell, E. Choroba,
Graham Knop, Hauke D, H.Merijn Brand, Hugo van der Sanden, James E Keenan,
Johan Vromans, Karen Etheridge, Karl Williamson, Paul Evans, Sawyer X, Steve
Hay, Tomasz Konojacki, Tom Hukins, 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://rt.perl.org/>.  There may also be information at
L<http://www.perl.org/>, the Perl Home Page.

If you believe you have an unreported bug, please run the L<perlbug> program
included with your release.  Be sure to trim your bug down to a tiny but
sufficient test case.  Your bug report, along with the output of C<perl -V>,
will be sent off to perlbug@perl.org to be analysed by the Perl porting team.

If the bug you are reporting has security implications which make it
inappropriate to send to a publicly archived mailing list, 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
