++ed by:
CXW IOANR YKO PERLER BINJOY

177 PAUSE users
171 non-PAUSE users.

Matthew Horsfall (alh)
and 1 contributors

NAME

perldelta - what is new for perl v5.23.2

DESCRIPTION

This document describes differences between the 5.23.1 release and the 5.23.2 release.

If you are upgrading from an earlier release such as 5.23.0, first read perl5231delta, which describes differences between 5.23.0 and 5.23.1.

Incompatible Changes

Nested declarations are now disallowed

A my, our, or state declaration is no longer allowed inside of another my, our, or state declaration.

For example, these are now fatal:

   my ($x, my($y));
   our (my $x);

[perl #125587]

[perl #121058]

Deprecations

sysread(), syswrite(), recv() and send() are deprecated on :utf8 handles

The sysread(), recv(), syswrite() and send() operators are deprecated on handles that have the :utf8 layer, either explicitly, or implicitly, eg., with the :encoding(UTF-16LE) layer.

Both sysread() and recv() currently use only the :utf8 flag for the stream, ignoring the actual layers. Since sysread() and recv() do no UTF-8 validation they can end up creating invalidly encoded scalars.

Similarly, syswrite() and send() use only the :utf8 flag, otherwise ignoring any layers. If the flag is set, both write the value UTF-8 encoded, even if the layer is some different encoding, such as the example above.

Ideally, all of these operators would completely ignore the :utf8 state, working only with bytes, but this would result in silently breaking existing code. To avoid this a future version of perl will throw an exception when any of sysread(), recv(), syswrite() or send() are called on handle with the :utf8 layer.

Performance Enhancements

  • Creating Perl debugger data structures (see "Debugger Internals" in perldebguts) for XSUBs and const subs has been removed. This removed one glob/scalar combo for each unique .c file that XSUBs and const subs came from. On startup (perl -e"0") about half a dozen glob/scalar debugger combos were created. Loading XS modules created more glob/scalar combos. These things were created regardless if the perl debugger was being used or not, unlike for pure perl subs, and ignores that the perl debugger can not debug C code.

  • Single arguments in list assign are now slightly faster:

      ($x) = (...);
      (...) = ($x);

Modules and Pragmata

Updated Modules and Pragmata

  • The PathTools module collection has been upgraded from version 3.55 to 3.56.

    Minor optimizations. [perl #125712]

  • Attribute::Handlers has been upgraded from version 0.97 to 0.99.

  • CPAN::Meta::YAML has been upgraded from version 0.016 to 0.017.

  • Encode has been upgraded from version 2.75 to 2.76.

  • ExtUtils::ParseXS has been upgraded from version 3.28 to 3.29.

  • ExtUtils::Typemaps has been upgraded from version 3.28 to 3.29.

  • File::Find has been upgraded from version 1.29 to 1.30.

  • File::Spec has been upgraded from version 3.56 to 3.57.

  • Filter::Util::Call has been upgraded from version 1.54 to 1.55.

  • Hash::Util has been upgraded from version 0.18 to 0.19.

    unlock_hashref_recurse and unlock_hash_recurse didn't actually unlock parts of the data structures...

    ...now they do.

  • Module::CoreList has been upgraded from version 5.20150720 to 5.20150820.

  • perlfaq has been upgraded from version 5.021009 to 5.021010.

  • POSIX has been upgraded from version 1.55 to 1.56.

  • Term::Cap has been upgraded from version 1.15 to 1.17.

  • Unicode::UCD has been upgraded from version 0.61 to 0.62.

Documentation

Changes to Existing Documentation

perlpolicy

  • This note has been added to perlpolicy:

      While civility is required, kindness is encouraged; if you have any doubt
      about whether you are being civil, simply ask yourself, "Am I being kind?"
      and aspire to that.

perlvar

  • Use of $OLD_PERL_VERSION is now discouraged.

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 perldiag.

New Diagnostics

New Errors

  • Can't redeclare "%s" in "%s"

    (F) A "my", "our" or "state" declaration was found within another declaration, such as my ($x, my($y), $z) or our (my $x).

New Warnings

  • %s() is deprecated on :utf8 handles

    (W deprecated) The sysread(), recv(), syswrite() and send() operators are deprecated on handles that have the :utf8 layer, either explicitly, or implicitly, eg., with the :encoding(UTF-16LE) layer.

    Both sysread() and recv() currently use only the :utf8 flag for the stream, ignoring the actual layers. Since sysread() and recv() do no UTF-8 validation they can end up creating invalidly encoded scalars.

    Similarly, syswrite() and send() use only the :utf8 flag, otherwise ignoring any layers. If the flag is set, both write the value UTF-8 encoded, even if the layer is some different encoding, such as the example above.

    Ideally, all of these operators would completely ignore the :utf8 state, working only with bytes, but this would result in silently breaking existing code. To avoid this a future version of perl will throw an exception when any of sysread(), recv(), syswrite() or send() are called on handle with the :utf8 layer.

Changes to Existing Diagnostics

  • The diagnostic Hexadecimal float: internal error has been changed to Hexadecimal float: internal error (%s) to include more information.

Configuration and Compilation

  • Configure should handle spaces in paths a little better.

Testing

  • A new test (t/op/aassign.t) has been added to test the list assignment operator OP_AASSIGN.

Internal Changes

  • PL_sawalias and GPf_ALIASED_SV have been removed.

  • GvASSIGN_GENERATION and GvASSIGN_GENERATION_set have been removed.

Selected Bug Fixes

  • Perl can again be compiled with any Unicode version. This used to (mostly) work, but was lost in v5.18 through v5.20. The property Name_Alias did not exist prior to Unicode 5.0. Unicode::UCD incorrectly said it did. This has been fixed.

  • Very large code-points (beyond Unicode) in regular expressions no longer cause a buffer overflow in some cases when converted to UTF-8. [perl #125826]

  • The integer overflow check for the range operator (...) in list context now correctly handles the case where the size of the range is larger than the address space. This could happen on 32-bits with -Duse64bitint. [perl #125781]

  • A crash with %::=(); J->${\"::"} has been fixed. [perl #125541]

Acknowledgements

Perl 5.23.2 represents approximately 4 weeks of development since Perl 5.23.1 and contains approximately 22,000 lines of changes across 240 files from 23 authors.

Excluding auto-generated files, documentation and release tools, there were approximately 17,000 lines of changes to 140 .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 5.23.2:

Aaron Priven, Aristotle Pagaltzis, Chris 'BinGOs' Williams, Craig A. Berry, Dagfinn Ilmari Mannsåker, Daniel Dragan, David Mitchell, Ed J, Father Chrysostomos, H.Merijn Brand, Ivan Pozdeev, James E Keenan, Jarkko Hietaniemi, Karen Etheridge, Karl Williamson, Ludovic E. R. Tolhurst-Cleaver, Lukas Mai, Matthew Horsfall, Reini Urban, Ricardo Signes, Sisyphus, Steve Hay, 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 AUTHORS file in the Perl source distribution.

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 https://rt.perl.org/ . There may also be information at http://www.perl.org/ , the Perl Home Page.

If you believe you have an unreported bug, please run the 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 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.

SEE ALSO

The Changes file for an explanation of how to view exhaustive details on what changed.

The INSTALL file for how to build Perl.

The README file for general stuff.

The Artistic and Copying files for copyright information.