[ 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 v5.43.8
This document describes differences between the 5.43.7 release and the 5.43.8 release.
If you are upgrading from an earlier release such as 5.43.6, first read perl5437delta, which describes differences between 5.43.6 and 5.43.7.
XXX Any important notices here
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 ]
foreach can now use aliased referencesPerl version 5.22 introduced reference aliases, allowing a foreach loop iteration variable to create new aliases to references. Perl version 5.36 introduced foreach loops with multiple variables, consuming more than one input list item on each iteration. New in this version, the two features may now be used together, allowing multiple iteration variables where any of them are permitted to be reference aliases.
use v5.42;
use feature qw( refaliasing declared_refs );
my %hash = (
one => [1],
two => [2, 2],
);
foreach my ( $key, \@items ) ( %hash ) {
say "The $key array contains: @items";
}Currently both the refaliasing and declared_refs features remain experimental.
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 ]
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 ]
Before Unicode, Perl accepted any \w character in an identifier or other name, except the first character couldn't be a digit. Later, Unicode created two properties that described this. Even later, they found those properties to be insufficient, and created two new similar properties. These are the ones that perl has intended to use since: \p{XID_Start} and \p{XID_Continue}. (The X stands for "eXtended" and indicates these are the more modern versions.)
(And even later, long after Perl identifier rules were formed using the above properties, Unicode added recommendations to further restrict legal identifier names. These were added to counter cases where, for example, programmers snuck code past reviewers using characters that look like other ones. The two properties are Identifier_Status and Identifier_Type. https://www.unicode.org/reports/tr39/. Perl currently doesn't do anything with these, except to furnish you the ability to use them in regular expressions.)
We soon discovered that there were 14 characters that match XID_Start and XID_Continue that don't also match \w. To avoid breaking code that had long relied on \w, we chose to not add those to the list of acceptable identifier characters.
It turns out that there are about 160 characters that match \w but not the Unicode XID properties. Thus they are illegal according to Unicode. Those are now explicitly forbidden in both Perl identifiers and regular expression group names. Previously, it was likely that their use in identifiers wouldn't work anyway; they could be accepted as initially as legal, but other code would later reject them, but with a message that had nothing to do with the underlying problem. However group names in regular expression patterns could contain illegal continuation characters and have a higher probablility of not being caught. That is now changed.
Only programs that do use utf8 can be affected, and then only characters that appear in the 2nd or later positions of the name. The characters that an identifier name can begin with are unchanged.
130 of the now unacceptable characters are 5 sets of 26 Latin letters that are enclosed by some shape, such as CIRCLED LATIN CAPITAL LETTER N. Another 8 are generic modifiers that add shapes around other characters; 5 are modifiers to Cyrillic numbers; and 16 are Arabic ligatures and isolated forms. The other two are GREEK YPOGEGRAMMENI and VERTICAL TILDE.
XXX Any deprecated features, syntax, modules etc. should be listed here.
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 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 ]
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
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 ]
XXX Remove this section if Porting/corelist-perldelta.pl did not add any content here.
XXX has been upgraded from version A.xx to B.yy.
XXX If there was something important to note about this change, include that here.
XXX Remove this section if Porting/corelist-perldelta.pl did not add any content here.
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.
XXX Changes which create new files in pod/ go here.
XXX Description of the purpose of the new file here
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 Description of the change here
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.
XXX Newly added diagnostic messages go under here, separated into "New Errors" and "New Warnings"
\x{%X} is a \w char that isn't valid in a name "%s"
In most cases where this message now appears, an error would have occurred anyway, but the text would not have been helpful in finding the problem.
XXX message
XXX Changes (i.e. rewording) of diagnostic messages go here
XXX Describe change here
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 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 ].
It is now possible to pass to Configure the values dealing with POSIX locale categories, overriding its automatic calculation of these. This enables cross-compilation to work. The easiest way to do this is to extract the C program that does the calculation from Configure and then run it on the target machine, and then pass the values it outputs to Configure on the other machine. Porting/Glossary has examples. [GH #22992]
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
When testing embedding, add a sanity check to ensure the libperl we link against matches the perl we are building. [GH #22125]
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. ]
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
XXX List any platforms that this version of perl no longer compiles on.
XXX
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
When testing embedding, ensure we link against the correct static libperl. [GH #22125]
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 ]
Fixed a bug in the "sv_numeq" in perlapi API where values with numeric ("0+") overloading but not equality or numeric comparison overloading would always be compared as floating point values. This could lead to large integers being reported as equal when they weren't.
Fixed a bug in "sv_numeq" in perlapi where the SV_SKIP_OVERLOAD flag would skip operator overloading, but would still honor numeric ("0+") overloading.
Added "sv_numne" in perlapi, sv_numle, sv_numlt, sv_numge, sv_numgt and "sv_numcmp" in perlapi APIs that perform numeric comparison in the same way perl does, including overloading. Separate APIs for each comparison are needed to invoke their corresponding overload when needed. Inspired by [GH #23918]
This also extends the sv_numeq API to support SV_FORCE_OVERLOAD.
Added the AMGf_force_scalar flag to the "amagic_call" in perlapi API to force scalar context for overload calls.
Added the AMGf_force_overload flag to the "amagic_call" in perlapi API to allow forcing overloading to be honored even in the context of no overloading;.
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".
XXX Include references to GitHub issues and PRs as: [GH #12345] and the release manager will later use a regex to expand these into links.
[ List each fix as an =item entry ]
sort() optimizes common comparisons from calling the OP tree for a comparison block into a call to a C function. The C function used for overloaded numeric comparisons did not handle the case where there was no comparison overload but there was a numeric ("0+") overload correctly, losing precision for large overloaded integer arguments that are not exactly representable as a Perl floating point value (NV). [GH #23956]
When a scalar variable used as the target of a filehandle is undef'ed while being output, garbage bytes would be left in that scalar. [GH #24008]
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
XXX Add anything here that we forgot to add, or were mistaken about, in the perldelta of a previous release.
XXX If any significant core contributor or member of the CPAN community has died, add a short obituary here.
XXX Generate this with:
perl Porting/acknowledgements.pl v5.43.7..HEADIf 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 https://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.
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:
perlthanksThis will send an email to the Perl 5 Porters list with your show of thanks.
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.