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NAME

[ this is a template for a new perldelta file. Any text flagged as XXX needs to be processed before release. ]

perldelta - what is new for perl v5.35.2

DESCRIPTION

This document describes differences between the 5.35.1 release and the 5.35.2 release.

If you are upgrading from an earlier release such as 5.35.0, first read perl5351delta, which describes differences between 5.35.0 and 5.35.1.

Notice

XXX Any important notices here

Core Enhancements

XXX New core language features go here. Summarize user-visible core language enhancements. Particularly prominent performance optimisations could go here, but most should go in the "Performance Enhancements" section.

[ List each enhancement as a =head2 entry ]

Security

XXX Any security-related notices go here. In particular, any security vulnerabilities closed should be noted here rather than in the "Selected Bug Fixes" section.

[ List each security issue as a =head2 entry ]

Incompatible Changes

XXX For a release on a stable branch, this section aspires to be:

There are no changes intentionally incompatible with 5.XXX.XXX
If any exist, they are bugs, and we request that you submit a
report.  See L</Reporting Bugs> below.

[ List each incompatible change as a =head2 entry ]

Deprecations

XXX Any deprecated features, syntax, modules etc. should be listed here.

Module removals

XXX Remove this section if not applicable.

The following modules will be removed from the core distribution in a future release, and will at that time need to be installed from CPAN. Distributions on CPAN which require these modules will need to list them as prerequisites.

The core versions of these modules will now issue "deprecated"-category warnings to alert you to this fact. To silence these deprecation warnings, install the modules in question from CPAN.

Note that these are (with rare exceptions) fine modules that you are encouraged to continue to use. Their disinclusion from core primarily hinges on their necessity to bootstrapping a fully functional, CPAN-capable Perl installation, not usually on concerns over their design.

XXX

XXX Note that deprecated modules should be listed here even if they are listed as an updated module in the "Modules and Pragmata" section.

[ List each other deprecation as a =head2 entry ]

Performance Enhancements

XXX Changes which enhance performance without changing behaviour go here. There may well be none in a stable release.

[ List each enhancement as an =item entry ]

  • XXX

Modules and Pragmata

XXX All changes to installed files in cpan/, dist/, ext/ and lib/ go here. If Module::CoreList is updated, generate an initial draft of the following sections using Porting/corelist-perldelta.pl. A paragraph summary for important changes should then be added by hand. In an ideal world, dual-life modules would have a Changes file that could be cribbed.

The list of new and updated modules is modified automatically as part of preparing a Perl release, so the only reason to manually add entries here is if you're summarising the important changes in the module update. (Also, if the manually-added details don't match the automatically-generated ones, the release manager will have to investigate the situation carefully.)

[ Within each section, list entries as an =item entry ]

New Modules and Pragmata

  • XXX Remove this section if not applicable.

Updated Modules and Pragmata

  • perl5db.pl has been upgraded from version 1.60 to 1.61.

    The v command works again, and now has some tests.

Removed Modules and Pragmata

  • XXX

Documentation

XXX Changes to files in pod/ go here. Consider grouping entries by file and be sure to link to the appropriate page, e.g. perlfunc.

New Documentation

XXX Changes which create new files in pod/ go here.

XXX

XXX Description of the purpose of the new file here

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 https://github.com/Perl/perl5/issues.

XXX Changes which significantly change existing files in pod/ go here. However, any changes to pod/perldiag.pod should go in the "Diagnostics" section.

Additionally, the following selected changes have been made:

XXX

  • XXX Description of the change here

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.

XXX New or changed warnings emitted by the core's C code go here. Also include any changes in perldiag that reconcile it to the C code.

New Diagnostics

XXX Newly added diagnostic messages go under here, separated into New Errors and New Warnings

New Errors

New Warnings

Changes to Existing Diagnostics

XXX Changes (i.e. rewording) of diagnostic messages go here

  • XXX Describe change here

Utility Changes

XXX Changes to installed programs such as perldoc and xsubpp go here. Most of these are built within the directory utils.

[ List utility changes as a =head2 entry for each utility and =item entries for each change Use XXX with program names to get proper documentation linking. ]

XXX

  • XXX

Configuration and Compilation

XXX Changes to Configure, installperl, installman, and analogous tools go here. Any other changes to the Perl build process should be listed here. However, any platform-specific changes should be listed in the "Platform Support" section, instead.

[ List changes as an =item entry ].

  • XXX

Testing

XXX Any significant changes to the testing of a freshly built perl should be listed here. Changes which create new files in t/ go here as do any large changes to the testing harness (e.g. when parallel testing was added). Changes to existing files in t/ aren't worth summarizing, although the bugs that they represent may be covered elsewhere.

XXX If there were no significant test changes, say this:

Tests were added and changed to reflect the other additions and changes in this release.

XXX If instead there were significant changes, say this:

Tests were added and changed to reflect the other additions and changes in this release. Furthermore, these significant changes were made:

[ List each test improvement as an =item entry ]

  • XXX

Platform Support

XXX Any changes to platform support should be listed in the sections below.

[ Within the sections, list each platform as an =item entry with specific changes as paragraphs below it. ]

New Platforms

XXX List any platforms that this version of perl compiles on, that previous versions did not. These will either be enabled by new files in the hints/ directories, or new subdirectories and README files at the top level of the source tree.

XXX-some-platform

XXX

Discontinued Platforms

XXX List any platforms that this version of perl no longer compiles on.

XXX-some-platform

XXX

Platform-Specific Notes

XXX List any changes for specific platforms. This could include configuration and compilation changes or changes in portability/compatibility. However, changes within modules for platforms should generally be listed in the "Modules and Pragmata" section.

XXX-some-platform

XXX

Internal Changes

XXX Changes which affect the interface available to XS code go here. Other significant internal changes for future core maintainers should be noted as well.

[ List each change as an =item entry ]

  • Reading the string form of an integer value no longer sets the flag SVf_POK. The string form is still cached internally, and still re-read directly by the macros SvPV(sv) etc (inline, without calling a C function). XS code that already the APIs to get values will not be affected by this change. XS code that accesses flags directly instead of using API calls to express its intent might break, but such code likely is already buggy if passed some other values, such as floating point values or objects with string overloading.

    This small change permits code (such as JSON serealisers) to reliably determine between

    • a value that was initially written as an integer, but then read as a string

      my $answer = 42;
print "The answer is $answer\n";

    • that same value that was initially written as a string, but then read as an integer

      my $answer = "42";
print "That doesn't look right\n"
    unless $answer == 6 * 9;

    For the first case (originally written as an integer), we now have:

    use Devel::Peek;
my $answer = 42;
Dump ($answer);
my $void = "$answer";
print STDERR "\n";
Dump($answer)


SV = IV(0x562538925778) at 0x562538925788
  REFCNT = 1
  FLAGS = (IOK,pIOK)
  IV = 42

SV = PVIV(0x5625389263c0) at 0x562538925788
  REFCNT = 1
  FLAGS = (IOK,pIOK,pPOK)
  IV = 42
  PV = 0x562538919b50 "42"\0
  CUR = 2
  LEN = 10

    For the second (originally written as a string), we now have:

    use Devel::Peek;
my $answer = "42";
Dump ($answer);
my $void = $answer == 6 * 9;
print STDERR "\n";
Dump($answer)'


SV = PV(0x5586ffe9bfb0) at 0x5586ffec0788
  REFCNT = 1
  FLAGS = (POK,IsCOW,pPOK)
  PV = 0x5586ffee7fd0 "42"\0
  CUR = 2
  LEN = 10
  COW_REFCNT = 1

SV = PVIV(0x5586ffec13c0) at 0x5586ffec0788
  REFCNT = 1
  FLAGS = (IOK,POK,IsCOW,pIOK,pPOK)
  IV = 42
  PV = 0x5586ffee7fd0 "42"\0
  CUR = 2
  LEN = 10
  COW_REFCNT = 1

    (One can't rely on the presence or absence of the flag SVf_IsCOW to determine the history of operations on a scalar.)

    Previously both cases would be indistinguishable, with all 4 flags set:

    SV = PVIV(0x55d4d62edaf0) at 0x55d4d62f0930
  REFCNT = 1
  FLAGS = (IOK,POK,pIOK,pPOK)
  IV = 42
  PV = 0x55d4d62e1740 "42"\0
  CUR = 2
  LEN = 10

    (and possibly SVf_IsCOW, but not always)

    This now means that if XS code really needs to determine which form a value was first written as, it should implement logic roughly

    if (flags & SVf_IOK|SVf_NOK) && !(flags & SVf_POK)
    serealise as number
else if (flags & SVf_POK)
    serealise as string
else
    the existing guesswork ...

    Note that this doesn't cover "dualvars" - scalars that report different values when asked for their string form or number form (such as $!). Most serialisation formats cannot represent such duplicity.

    the existing guesswork remains because as well as dualvars, values might be undef, references, overloaded references, typeglobs and other things that Perl itself can represent but do not map one-to-one into external formats, so need some amount of approximation or encapsulation.

Selected Bug Fixes

XXX Important bug fixes in the core language are summarized here. Bug fixes in files in ext/ and lib/ are best summarized in "Modules and Pragmata".

[ List each fix as an =item entry ]

  • The flags on the OPTVAL parameter to setsockopt() were previously checked before magic was called, possibly treating a numeric value as a packed buffer or vice versa. It also ignored the UTF-8 flag, potentially treating the internal representation of an upgraded SV as the bytes to supply to the setsockopt() system call. (github #18660)

Known Problems

XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any tests that had to be TODOed for the release would be noted here. Unfixed platform specific bugs also go here.

[ List each fix as an =item entry ]

  • XXX

Errata From Previous Releases

  • XXX Add anything here that we forgot to add, or were mistaken about, in the perldelta of a previous release.

  • The Unicode::Unihan CPAN module doesn't work on recent Unicode versions, so references to it have been removed in 5.35.1.

  • The definition for the ASSUME() macro, broken on Windows in 5.34, has been fixed in 5.35.1.

Obituary

XXX If any significant core contributor or member of the CPAN community has died, add a short obituary here.

Acknowledgements

XXX Generate this with:

perl Porting/acknowledgements.pl v5.35.1..HEAD

Reporting Bugs

If you find what you think is a bug, you might check the perl bug database at https://github.com/Perl/perl5/issues. There may also be information at http://www.perl.org/, the Perl Home Page.

If you believe you have an unreported bug, please open an issue at 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 "SECURITY VULNERABILITY CONTACT INFORMATION" in perlsec for details of how to report the issue.

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 perlthanks program:

perlthanks

This will send an email to the Perl 5 Porters list with your show of thanks.

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.