5 [ this is a template for a new perldelta file. Any text flagged as XXX needs
6 to be processed before release. ]
8 perldelta - what is new for perl v5.21.1
12 This document describes differences between the 5.21.0 release and the 5.21.1
15 If you are upgrading from an earlier release such as 5.20.0, first read
16 L<perl5210delta>, which describes differences between 5.20.0 and 5.21.0.
20 XXX Any important notices here
22 =head1 Core Enhancements
24 XXX New core language features go here. Summarize user-visible core language
25 enhancements. Particularly prominent performance optimisations could go
26 here, but most should go in the L</Performance Enhancements> section.
28 [ List each enhancement as a =head2 entry ]
32 XXX Any security-related notices go here. In particular, any security
33 vulnerabilities closed should be noted here rather than in the
34 L</Selected Bug Fixes> section.
36 [ List each security issue as a =head2 entry ]
38 =head1 Incompatible Changes
40 XXX For a release on a stable branch, this section aspires to be:
42 There are no changes intentionally incompatible with 5.XXX.XXX
43 If any exist, they are bugs, and we request that you submit a
44 report. See L</Reporting Bugs> below.
46 [ List each incompatible change as a =head2 entry ]
50 XXX Any deprecated features, syntax, modules etc. should be listed here.
52 =head2 Module removals
54 XXX Remove this section if inapplicable.
56 The following modules will be removed from the core distribution in a
57 future release, and will at that time need to be installed from CPAN.
58 Distributions on CPAN which require these modules will need to list them as
61 The core versions of these modules will now issue C<"deprecated">-category
62 warnings to alert you to this fact. To silence these deprecation warnings,
63 install the modules in question from CPAN.
65 Note that these are (with rare exceptions) fine modules that you are encouraged
66 to continue to use. Their disinclusion from core primarily hinges on their
67 necessity to bootstrapping a fully functional, CPAN-capable Perl installation,
68 not usually on concerns over their design.
74 XXX Note that deprecated modules should be listed here even if they are listed
75 as an updated module in the L</Modules and Pragmata> section.
79 [ List each other deprecation as a =head2 entry ]
81 =head1 Performance Enhancements
83 XXX Changes which enhance performance without changing behaviour go here.
84 There may well be none in a stable release.
86 [ List each enhancement as a =item entry ]
96 =head1 Modules and Pragmata
98 XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
99 go here. If Module::CoreList is updated, generate an initial draft of the
100 following sections using F<Porting/corelist-perldelta.pl>. A paragraph summary
101 for important changes should then be added by hand. In an ideal world,
102 dual-life modules would have a F<Changes> file that could be cribbed.
104 [ Within each section, list entries as a =item entry ]
106 =head2 New Modules and Pragmata
116 =head2 Updated Modules and Pragmata
122 L<Carp> has been upgraded from version 1.3301 to 1.34.
124 Carp::Heavy now ignores version mismatches with Carp if Carp is newer
125 than 1.12, since Carp::Heavy's guts were merged into Carp at that
127 L<[perl #121574]|https://rt.perl.org/Ticket/Display.html?id=121574>
131 L<Digest::SHA> has been upgraded from version 5.88 to 5.91.
133 Numerous enhancements, bug fixes and performance improvements have been made.
134 See the F<Changes> file in the CPAN distribution for full details.
138 L<Math::BigRat> has been upgraded from version 0.2606 to 0.2607.
140 Synchronize POD changes from the CPAN release.
144 L<perl5db.pl> has been upgraded from version 1.44 to 1.45.
146 fork() in the debugger under C<tmux> will now create a new window for
147 the forked process. L<[perl
148 #121333]|https://rt.perl.org/Ticket/Display.html?id=121333>
150 The debugger now saves the current working directory on startup and
151 restores it when you restart your program with C<R> or <rerun>. L<[perl
152 #121509]|https://rt.perl.org/Ticket/Display.html?id=121509>
156 L<Term::Cap> has been upgraded from version 1.15 to 1.16.
158 The last resort attempt to fake up a termcap from terminfo now works.
162 L<Unicode::Collate> has been upgraded from version 1.04 to 1.07.
164 Version 0.67's improved discontiguous contractions is invalidated by default
165 and is supported as a parameter 'long_contraction'.
169 L<Unicode::Normalize> has been upgraded from version 1.17 to 1.18.
171 The XSUB implementation has been removed in favour of pure Perl.
175 =head2 Removed Modules and Pragmata
187 XXX Changes to files in F<pod/> go here. Consider grouping entries by
188 file and be sure to link to the appropriate page, e.g. L<perlfunc>.
190 =head2 New Documentation
192 XXX Changes which create B<new> files in F<pod/> go here.
196 XXX Description of the purpose of the new file here
198 =head2 Changes to Existing Documentation
200 XXX Changes which significantly change existing files in F<pod/> go here.
201 However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
210 XXX Description of the change here
216 The following additions or changes have been made to diagnostic output,
217 including warnings and fatal error messages. For the complete list of
218 diagnostic messages, see L<perldiag>.
220 XXX New or changed warnings emitted by the core's C<C> code go here. Also
221 include any changes in L<perldiag> that reconcile it to the C<C> code.
223 =head2 New Diagnostics
225 XXX Newly added diagnostic messages go under here, separated into New Errors
234 XXX L<message|perldiag/"message">
244 XXX L<message|perldiag/"message">
248 =head2 Changes to Existing Diagnostics
250 XXX Changes (i.e. rewording) of diagnostic messages go here
256 L<Unsuccessful %s on filename containing newline|perldiag/"Unsuccessful %s on filename containing newline">
258 This warning is now only produced when the newline is at the end of
263 =head1 Utility Changes
265 XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go here.
266 Most of these are built within the directories F<utils> and F<x2p>.
268 [ List utility changes as a =head2 entry for each utility and =item
269 entries for each change
270 Use L<XXX> with program names to get proper documentation linking. ]
282 =head1 Configuration and Compilation
284 XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
285 go here. Any other changes to the Perl build process should be listed here.
286 However, any platform-specific changes should be listed in the
287 L</Platform Support> section, instead.
289 [ List changes as a =item entry ].
301 XXX Any significant changes to the testing of a freshly built perl should be
302 listed here. Changes which create B<new> files in F<t/> go here as do any
303 large changes to the testing harness (e.g. when parallel testing was added).
304 Changes to existing files in F<t/> aren't worth summarizing, although the bugs
305 that they represent may be covered elsewhere.
307 [ List each test improvement as a =item entry ]
317 =head1 Platform Support
319 XXX Any changes to platform support should be listed in the sections below.
321 [ Within the sections, list each platform as a =item entry with specific
322 changes as paragraphs below it. ]
326 XXX List any platforms that this version of perl compiles on, that previous
327 versions did not. These will either be enabled by new files in the F<hints/>
328 directories, or new subdirectories and F<README> files at the top level of the
333 =item XXX-some-platform
339 =head2 Discontinued Platforms
341 XXX List any platforms that this version of perl no longer compiles on.
345 =item XXX-some-platform
351 =head2 Platform-Specific Notes
353 XXX List any changes for specific platforms. This could include configuration
354 and compilation changes or changes in portability/compatibility. However,
355 changes within modules for platforms should generally be listed in the
356 L</Modules and Pragmata> section.
360 =item XXX-some-platform
366 =head1 Internal Changes
368 XXX Changes which affect the interface available to C<XS> code go here. Other
369 significant internal changes for future core maintainers should be noted as
372 [ List each change as a =item entry ]
382 =head1 Selected Bug Fixes
384 XXX Important bug fixes in the core language are summarized here. Bug fixes in
385 files in F<ext/> and F<lib/> are best summarized in L</Modules and Pragmata>.
387 [ List each fix as a =item entry ]
393 index() and rindex() no longer crash when used on strings over 2GB in
395 L<[perl #121562]|https://rt.perl.org/Ticket/Display.html?id=121562>.
399 =head1 Known Problems
401 XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
402 tests that had to be C<TODO>ed for the release would be noted here. Unfixed
403 platform specific bugs also go here.
405 [ List each fix as a =item entry ]
415 =head1 Errata From Previous Releases
421 XXX Add anything here that we forgot to add, or were mistaken about, in
422 the perldelta of a previous release.
428 XXX If any significant core contributor has died, we've added a short obituary
431 =head1 Acknowledgements
433 XXX Generate this with:
435 perl Porting/acknowledgements.pl v5.21.1..HEAD
437 =head1 Reporting Bugs
439 If you find what you think is a bug, you might check the articles recently
440 posted to the comp.lang.perl.misc newsgroup and the perl bug database at
441 https://rt.perl.org/ . There may also be information at
442 http://www.perl.org/ , the Perl Home Page.
444 If you believe you have an unreported bug, please run the L<perlbug> program
445 included with your release. Be sure to trim your bug down to a tiny but
446 sufficient test case. Your bug report, along with the output of C<perl -V>,
447 will be sent off to perlbug@perl.org to be analysed by the Perl porting team.
449 If the bug you are reporting has security implications, which make it
450 inappropriate to send to a publicly archived mailing list, then please send it
451 to perl5-security-report@perl.org. This points to a closed subscription
452 unarchived mailing list, which includes all the core committers, who will be
453 able to help assess the impact of issues, figure out a resolution, and help
454 co-ordinate the release of patches to mitigate or fix the problem across all
455 platforms on which Perl is supported. Please only use this address for
456 security issues in the Perl core, not for modules independently distributed on
461 The F<Changes> file for an explanation of how to view exhaustive details on
464 The F<INSTALL> file for how to build Perl.
466 The F<README> file for general stuff.
468 The F<Artistic> and F<Copying> files for copyright information.