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perl5301delta - what is new for perl v5.30.1


This document describes differences between the 5.30.0 release and the 5.30.1 release.

If you are upgrading from an earlier release such as 5.28.0, first read perl5300delta, which describes differences between 5.28.0 and 5.30.0.

Incompatible Changes

There are no changes intentionally incompatible with 5.30.1. If any exist, they are bugs, and we request that you submit a report. See "Reporting Bugs" below.

Modules and Pragmata

Updated Modules and Pragmata


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, send email to

Additionally, documentation has been updated to reference GitHub as the new canonical repository and to describe the new GitHub pull request workflow.

Configuration and Compilation

  • The ECHO macro is now defined. This is used in a dtrace rule that was originally changed for FreeBSD, and the FreeBSD make apparently predefines it. The Solaris make does not predefine ECHO which broke this rule on Solaris. [perl #17057]


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

Platform Support

Platform-Specific Notes


The locale tests could crash on Win32 due to a Windows bug, and separately due to the CRT throwing an exception if the locale name wasn't validly encoded in the current code page.

For the second we now decode the locale name ourselves, and always decode it as UTF-8.

[perl #16922]

Selected Bug Fixes

  • Setting $) now properly sets supplementary group ids, if you have the necessary privileges. [perl #17031]

  • readline @foo now evaluates @foo in scalar context. Previously, it would be evaluated in list context, and since readline() pops only one argument from the stack, the stack could underflow, or be left with unexpected values on it. [perl #16929]

  • sv_gets() now recovers better if the target SV is modified by a signal handler. [perl #16960]

  • Matching a non-SVf_UTF8 string against a regular expression containing Unicode literals could leak an SV on each match attempt. [perl #17140]

  • sprintf("%.*a", -10000, $x) would cause a buffer overflow due to mishandling of the negative precision value. [perl #16942]

  • scalar() on a reference could cause an erroneous assertion failure during compilation. [perl #16969]


Perl 5.30.1 represents approximately 6 months of development since Perl 5.30.0 and contains approximately 4,700 lines of changes across 67 files from 14 authors.

Excluding auto-generated files, documentation and release tools, there were approximately 910 lines of changes to 20 .pm, .t, .c and .h files.

Perl continues to flourish into its fourth decade thanks to a vibrant community of users and developers. The following people are known to have contributed the improvements that became Perl 5.30.1:

Chris 'BinGOs' Williams, Dan Book, David Mitchell, Hugo van der Sanden, James E Keenan, Karen Etheridge, Karl Williamson, Manuel Mausz, Max Maischein, Nicolas R., Sawyer X, Steve Hay, Tom Hukins, 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 perl bug database at There may also be information at, 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 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 "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:


This 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.