[ 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 v5.45.4
This document describes differences between the 5.45.3 release and the 5.45.4 release.
If you are upgrading from an earlier release such as 5.45.2, first read perl5453delta, which describes differences between 5.45.2 and 5.45.3.
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 ]
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 ]
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 ]
Changes have been made to the "super-linear cache", which is used to avoid excessive backtracking in some regexes which include quantifiers on variable-length sub-patterns, such as (a|bc)* and (ab+){2,}. This change may reduce the amount of backtracking that takes place, and may reduce the amount of temporary memory used for the cache.
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"
XXX message
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 ].
XXX
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
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
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 ]
During regex compilation, S_reg will attempt to flatten nested BRANCH structures, in an attempt to give the TRIE optimizer more alternations to consider. The intent is that patterns that were previously compiled into two or more adjacent TRIE nodes might now get compiled into a single (or at least, fewer) TRIE node(s).
Locale thread-safety is now enabled by default for the next few v5.45 development releases.
This feature, introduced with default-off in v5.45.3, is never turned on for builds that don't have threads, and on platforms where perl believes that the locale handling is natively thread-safe.
Otherwise, the feature is on by default during a portion of the remaining 5.45 development cycle, so as to test it in the field, but the intention is to make it opt-in for the official 5.46 release. To turn it off, pass this to Configure:
-Accflags=-DNO_EMULATE_THREAD_SAFE_LOCALESThe inline function Perl_newSV_type now only handles the SV types most commonly seen at runtime. Perl_newSV_type_generic has been added as a non-inline function that can handle all SV types. This change reduces binary bloating and increases the chances of Perl_newSV_type being succesfully inlined.
When a shifted array is unshifted, Perl_av_extend_guts used to perform a (key *maxp - 10)> check and always reallocate. That check dates from Perl 3.0 and the rationale for it seems to have been lost to time. (It may have been to encourage array growth, but the general levers for doing so have changed significantly over time.)
Always reallocating when it is not strictly necessary could cause Perl applications that repeatedly perform a mixture of shift/push operations (or similar) to suffer from unnecessary allocator thrashing. Perl_av_extend_guts will now only reallocate if the array really is out of space and must be extended.
XXX
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 ]
Line number information is stored rather than discarded when an anonymous subroutine is encountered during compilation. This should improve the accuracy of line numbers emitted by diagnostic messages and `caller()` for code following an anonymous subroutine declaration.
Note that (i) this change could break any tests that hardcode the less-accurate line numbers (ii) further improvements to line number accuracy may follow within this development cycle.
[GH #24396]
A regular expression performing a greedy match of a UTF8 character may have incorrectly failed if the first attempt at a match was unsuccessful. Instead of skipping over all consecutive instances of that character, all consecutive characters that had the same first byte were skipped.
[GH #24916]
In some cases warnings that occurred while using unpack on an invalid UTF-8 marked string would result in an invalid free. [GH #24913]
Builds with PERL_NO_COW could crash when modifying or freeing boolean values. This has been fixed. [GH #19987]
goto within a defer block should now work more consistently. [GH #19240]
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 v5.45.3..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.