=encoding utf8

=head1 NAME

perl52510delta - what is new for perl v5.25.10

=head1 DESCRIPTION

This document describes differences between the 5.25.9 release and the 5.25.10
release.

If you are upgrading from an earlier release such as 5.25.8, first read
L<perl5259delta>, which describes differences between 5.25.8 and 5.25.9.

=head1 Modules and Pragmata

=head2 Updated Modules and Pragmata

=over 4

=item *

L<B> has been upgraded from version 1.65 to 1.68.

=item *

L<CPAN> has been upgraded from version 2.16 to 2.17.

=item *

L<feature> has been upgraded from version 1.46 to 1.47.

=item *

L<Getopt::Std> has been upgraded from version 1.11 to 1.12.

=item *

L<Module::CoreList> has been upgraded from version 5.20170120 to 5.20170220.

=item *

L<open> has been upgraded from version 1.10 to 1.11.

=item *

L<PerlIO> has been upgraded from version 1.09 to 1.10.

=item *

L<Storable> has been upgraded from version 2.61 to 2.62.

=item *

L<Thread::Queue> has been upgraded from version 3.11 to 3.12.

=item *

L<threads> has been upgraded from version 2.12 to 2.13.

=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 *

Use of unassigned code point or non-standalone grapheme for a delimiter will be a fatal error starting in Perl 5.30

This was changed to drop a leading C<v> in C<v5.30>, so it uses the same
style as other deprecation messages.

=item * 

"\c%c" is more clearly written simply as "%s".

It was decided to undeprecate the use of "\c%c", see L<http://www.nntp.perl.org/group/perl.perl5.porters/2017/02/msg242944.html>

=back

=head1 Platform Support

=head2 Platform-Specific Notes

=over 4

=item Windows

=over 4

=item *

Support for compiling perl on Windows using Microsoft Visual Studio 2015
(containing Visual C++ 14.0) has been added.

This version of VC++ includes a completely rewritten C run-time library, some
of the changes in which mean that work done to resolve a socket close() bug in
perl #120091 and perl #118059 is not workable in its current state with this
version of VC++.  Therefore, we have effectively reverted that bug fix for
VS2015 onwards on the basis that being able to build with VS2015 onwards is
more important than keeping the bug fix.  We may revisit this in the future to
attempt to fix the bug again in a way that is compatible with VS2015.

These changes do not affect compilation with GCC or with Visual Studio versions
up to and including VS2013, i.e. the bug fix is retained (unchanged) for those
compilers.

Note that you may experience compatibility problems if you mix a perl built
with GCC or VS E<lt>= VS2013 with XS modules built with VS2015, or if you mix a
perl built with VS2015 with XS modules built with GCC or VS E<lt>= VS2013.
Some incompatibility may arise because of the bug fix that has been reverted
for VS2015 builds of perl, but there may well be incompatibility anyway because
of the rewritten CRT in VS2015 (e.g. see discussion at
http://stackoverflow.com/questions/30412951).

=back

=back

=head1 Internal Changes

=over 4

=item *

The C<op_class()> API function has been added. This is like the existing
C<OP_CLASS()> macro, but can more accurately determine what struct an op
has been allocated as. For example C<OP_CLASS()> might return
C<OA_BASEOP_OR_UNOP> indicating that ops of this type are usually
allocated as an C<OP> or C<UNOP>; while C<op_class()> will return
C<OPclass_BASEOP> or C<OPclass_UNOP> as appropriate.

=item *

The output format of the C<op_dump()> function (as used by C<perl -Dx>)
has changed: it now displays an "ASCII-art" tree structure, and shows more
low-level details about each op, such as its address and class.

=back

=head1 Selected Bug Fixes

=over 4

=item *

Attempting to use the deprecated variable C<$#> as the object in an
indirect object method call could cause a heap use after free or
buffer overflow.  [perl #129274]

=item *

When checking for an indirect object method call in some rare cases
the parser could reallocate the line buffer but then continue to use
pointers to the old buffer.  [perl #129190]

=item *

Supplying a glob as the format argument to L<perlfunc/formline> would
cause an assertion failure.  [perl #130722]

=item *

Code like C< $value1 =~ qr/.../ ~~ $value2 > would have the match
converted into a qr// operator, leaving extra elements on the stack to
confuse any surrounding expression.  [perl #130705]

=item *

Since 5.24.0 in some obscure cases, a regex which included code blocks
from multiple sources (e.g. via embedded via qr// objects) could end up
with the wrong current pad and crash or give weird results. [perl #129881]

=item *

Occasionally C<local()>s in a code block within a patterns weren't being
undone when the pattern matching backtracked over the code block.
[perl #126697]

=item *

Using C<substr()> to modify a magic variable could access freed memory
in some cases.  [perl #129340]

=item *

Perl 5.25.9 was fixed so that under C<use utf8>, the entire Perl program
is checked that the UTF-8 is wellformed.  It turns out that several edge
cases were missed, and are now fixed.  [perl #126310] was the original
ticket.

=back

=head1 Acknowledgements

Perl 5.25.10 represents approximately 4 weeks of development since Perl 5.25.9
and contains approximately 12,000 lines of changes across 200 files from 25
authors.

Excluding auto-generated files, documentation and release tools, there were
approximately 6,700 lines of changes to 130 .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 5.25.10:

Aaron Crane, Abigail, Andreas König, Andy Lester, Chris 'BinGOs' Williams,
Christian Millour, Colin Newell, Dagfinn Ilmari Mannsåker, David Mitchell,
Hugo van der Sanden, James E Keenan, Jarkko Hietaniemi, Jerry D. Hedden, John
Lightsey, Karl Williamson, Neil Bowers, Pali, Renee Baecker, Sawyer X, Sergey
Aleynikov, Steffen Müller, Steve Hay, Tony Cook, Yves Orton, Zefram.

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 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
