path: root/pod/perldelta.pod

=encoding utf8

=head1 NAME

perldelta - what is new for perl v5.23.7

=head1 DESCRIPTION

This document describes differences between the 5.23.6 release and the 5.23.7
release.

If you are upgrading from an earlier release such as 5.23.5, first read
L<perl5236delta>, which describes differences between 5.23.5 and 5.23.6.

=head1 Core Enhancements

=head2 New C<\b{lb}> boundary in regular expressions

C<lb> stands for Line Break.  It is a Unicode property
that determines where a line of text is suitable to break (typically so
that it can be output without overflowing the available horizontal
space).  This capability has long been furnished by the
L<Unicode::LineBreak> module, but now a light-weight, non-customizable
version that is suitable for many purposes is in core Perl.

=head1 Security

=head2 fix out of boundary access in Win32 path handling

This is CVE-2015-8608.  For more information see
L<[perl #126755]|https://rt.perl.org/Ticket/Display.html?id=126755>

=head2 fix loss of taint in canonpath

This is CVE-2015-8607.  For more information see
L<[perl #126862]|https://rt.perl.org/Ticket/Display.html?id=126862>

=head2 Avoid accessing uninitialized memory in win32 C<crypt()>

Added validation that will detect both a short salt and invalid characters
in the salt.  L<[perl #126922]|https://rt.perl.org/Ticket/Display.html?id=126922>

=head1 Incompatible Changes

=head2 C<qr/\b{wb}/> is now tailored to Perl expectations

This is now more suited to be a drop-in replacement for plain C<\b>, but
giving better results for parsing natural language.  Previously it
strictly followed the current Unicode rules which calls for it to match
between each white space character.  Now it doesn't generally match
within spans of white space, behaving like C<\b> does.  See
L<perlrebackslash/\b{wb}>

=head1 Modules and Pragmata

=head2 Updated Modules and Pragmata

=over 4

=item *

The F<cpan/podlators/> bundle has been upgraded from version 2.28 to 4.04.

=item *

L<B> has been upgraded from version 1.61 to 1.62.

=item *

L<B::Deparse> has been upgraded from version 1.36 to 1.37.

=item *

L<Benchmark> has been upgraded from version 1.21 to 1.22.

=item *

L<bignum> has been upgraded from version 0.41 to 0.42.

=item *

L<Data::Dumper> has been upgraded from version 2.159 to 2.160.

=item *

L<ExtUtils::ParseXS> has been upgraded from version 3.30 to 3.31.

=item *

L<ExtUtils::Typemaps> has been upgraded from version 3.30 to 3.31.

=item *

L<File::Find> has been upgraded from version 1.32 to 1.33.

=item *

L<File::Spec> has been upgraded from version 3.60 to 3.62.

=item *

L<Math::BigInt> has been upgraded from version 1.999710 to 1.999715.

=item *

L<Math::BigInt::FastCalc> has been upgraded from version 0.38 to 0.40.

=item *

L<Math::BigRat> has been upgraded from version 0.260801 to 0.260802.

=item *

L<Module::CoreList> has been upgraded from version 5.20151220 to 5.20160120.

=item *

L<Pod::Usage> has been upgraded from version 1.67 to 1.68.

=item *

L<Test::Harness> has been upgraded from version 3.35 to 3.36.

=item *

L<Unicode::Normalize> has been upgraded from version 1.24 to 1.25.

=item *

L<Unicode::UCD> has been upgraded from version 0.63 to 0.64.

=item *

L<utf8> has been upgraded from version 1.18 to 1.19.

=back

=head1 Documentation

=head2 Changes to Existing Documentation

=head3 L<perlsyn>

=over 4

=item *

Fixed a broken example where C<=> was used instead of
C<==> in conditional in do/while example.

=back

=head3 L<perlfunc>

=over 4

=item *

Better explain meaning of negative PIDs in C<waitpid>.
L<[perl #127080]|https://rt.perl.org/Ticket/Display.html?id=127080>

=back

=head3 L<perlgit>

=over 4

=item *

Move sample commands into verbatim paragraphs.

=item *

Improve hyperlinks for all email addresses, RT tickets
and commit hashes.

=item *

Consistently refer to bisect.pl as F<Porting/bisect.pl>

=item *

Miscellaneous grammar and POD fixes.

=back

=head3 L<perlreftut>

=over 4

=item *

Fix some examples to be L<strict> clean.

=back

=head3 L<perlrebackslash>

=over 4

=item *

Clarify that in languages like Japanese and Thai, dictionary lookup
is required to determine word boundaries.

=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 Changes to Existing Diagnostics

=over 4

=item *

Accessing the C<IO> part of a glob as C<FILEHANDLE> instead of C<IO> is no
longer deprecated.  It is discouraged to encourage uniformity (so that, for
example, one can grep more easily) but it will not be removed.
L<[perl #127060]|https://rt.perl.org/Ticket/Display.html?id=127060>

=back

=head1 Configuration and Compilation

=over 4

=item *

F<Configure> no longer probes for F<libnm> by default.  Originally
this was the "New Math" library, but the name has been re-used by the
GNOME NetworkManager.
L<[perl #127131]|https://rt.perl.org/Ticket/Display.html?id=127131>

=item *

No longer generate EBCDIC POSIX-BC tables.  We don't believe anyone is
using Perl and POSIX-BC at this time, and by not generating these tables
it saves time during development, and makes the resulting tar ball smaller.

=item *

The Win32 miniperl now has a real C<getcwd> which increases build performance
resulting in C<getcwd()> being 605x faster in Win32 miniperl.

=back

=head1 Platform Support

=head2 Platform-Specific Notes

=over 4

=item *

On VMS, the math function prototypes in C<math.h> are now visible under C++.
Now building the POSIX extension with C++ will no longer crash.

=item *

VMS has had C<setenv/unsetenv> since v7.0 (released in 1996), C<Perl_vmssetenv>
now always uses C<setenv/unsetenv>.

=item *

Try more crypt algorithms in the tests, for OpenBSD. OpenBSD implements the
Blowfish algorithm, but not the MD5 one used by C<glibc>. Enhance the crypt and
taint tests to try both algorithms. If neither works, fall back to no algorithm.
The Blowfish salt is taken from the OpenBSD C<crypt(3)> page.

=item *

Use the C<fdclose()> function from FreeBSD if it is available.
L<[perl #126847]|https://rt.perl.org/Ticket/Display.html?id=126847>

=back

=head1 Internal Changes

=over 4

=item *

The obscure C<PL_timesbuf> variable, effectively a vestige of Perl 1, has
been removed. It was documented as deprecated in Perl 5.20, with a statement
that it would be removed early in the 5.21.x series; that has now finally
happened.
L<[perl #121351]|https://rt.perl.org/Ticket/Display.html?id=121351>

=item *

Remove unwarranted assertion in C<Perl_newATTRSUB_x()>. If a stub subroutine
definition with a prototype has been seen, then any subsequent stub (or
definition) of the same subroutine with an attribute was causing an assertion
failure because of a null pointer.
L<[perl #126845]|https://rt.perl.org/Ticket/Display.html?id=126845>

=item *

Replace C<::> with C<__> in C<ExtUtils::ParseXS> like it's done for
parameters/return values. This is more consistent, and simplifies writing XS
code wrapping C++ classes into a nested Perl namespace (it requires only
a typedef for C<Foo__Bar> rather than two, one for C<Foo_Bar> and the other
for C<Foo::Bar>).

=item *

Deprecate the C<to_utf8_case()> function, see
L<http://nntp.perl.org/group/perl.perl5.porters/233287>.

=back

=head1 Selected Bug Fixes

=over 4

=item *

A regression that allowed undeclared barewords in hash keys to work despite
strictures has been fixed.
L<[perl #126981]|https://rt.perl.org/Ticket/Display.html?id=126981>

=item *

Calls to the placeholder C<&PL_sv_yes> used internally when an C<import()>
or C<unimport()> method isn't found now correctly handle scalar context.
L<[perl #126042]|https://rt.perl.org/Ticket/Display.html?id=126042>

=item *

Fixed some problems introduced in 5.23.2 with list assignment dealing
with magic and XS functions returning their arguments.
L<[perl #126633]|https://rt.perl.org/Ticket/Display.html?id=126633>

=item *

Report more context when we see an array where we expect to see an
operator and avoid an assertion failure.
L<[perl #123737]|https://rt.perl.org/Ticket/Display.html?id=123737>

=item *

Modifying an array that was previously a package C<@ISA> no longer
causes assertion failures or crashes.
L<[perl #123788]|https://rt.perl.org/Ticket/Display.html?id=123788>

=item *

Retain binary compatibility across plain and DEBUGGING perl builds.
L<[perl #127212]|https://rt.perl.org/Ticket/Display.html?id=127212>

=item *

Avoid leaking memory when setting C<$ENV{foo}> on darwin.
L<[perl #126240]|https://rt.perl.org/Ticket/Display.html?id=126240>

=back

=head1 Known Problems

=over 4

=item *

Statically building perl is not currently working due to a problem
related to multiple definitions of the C<cp1252_encoding> in the
C<Encode> module.

=back

=head1 Acknowledgements

Perl 5.23.7 represents approximately 4 weeks of development since Perl 5.23.6
and contains approximately 87,000 lines of changes across 450 files from 21
authors.

Excluding auto-generated files, documentation and release tools, there were
approximately 67,000 lines of changes to 320 .pm, .t, .c and .h files.

Perl continues to flourish into its third decade thanks to a vibrant community
of users and developers. The following people are known to have contributed the
improvements that became Perl 5.23.7:

Aaron Crane, Andreas König, Andy Dougherty, Chris 'BinGOs' Williams, Craig A.
Berry, Dagfinn Ilmari Mannsåker, Daniel Dragan, David Golden, David Mitchell,
James E Keenan, Jarkko Hietaniemi, Karen Etheridge, Karl Williamson, Lukas Mai,
Mattia Barbon, Ricardo Signes, Stevan Little, Steve Hay, Todd Rinaldo, 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 articles recently
posted to the comp.lang.perl.misc newsgroup and 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 please send it
to perl5-security-report@perl.org.  This points to a closed subscription
unarchived mailing list, which includes all the core committers, who will be
able to help assess the impact of issues, figure out a resolution, and help
co-ordinate the release of patches to mitigate or fix the problem across all
platforms on which Perl is supported.  Please only use this address for
security issues in the Perl core, not for modules independently distributed on
CPAN.

=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