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 v5.21.3
12 This document describes differences between the 5.21.2 release and the 5.21.3
15 If you are upgrading from an earlier release such as 5.21.1, first read
16 L<perl5212delta>, which describes differences between 5.21.1 and 5.21.2.
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 ]
48 =head2 S<C<use UNIVERSAL '...'>> is now a fatal error
50 Importing functions from C<UNIVERSAL> has been deprecated since v5.12, and
51 is now a fatal error. S<C<"use UNIVERSAL">> without any arguments is still
56 XXX Any deprecated features, syntax, modules etc. should be listed here.
58 =head2 Module removals
60 XXX Remove this section if inapplicable.
62 The following modules will be removed from the core distribution in a
63 future release, and will at that time need to be installed from CPAN.
64 Distributions on CPAN which require these modules will need to list them as
67 The core versions of these modules will now issue C<"deprecated">-category
68 warnings to alert you to this fact. To silence these deprecation warnings,
69 install the modules in question from CPAN.
71 Note that these are (with rare exceptions) fine modules that you are encouraged
72 to continue to use. Their disinclusion from core primarily hinges on their
73 necessity to bootstrapping a fully functional, CPAN-capable Perl installation,
74 not usually on concerns over their design.
80 XXX Note that deprecated modules should be listed here even if they are listed
81 as an updated module in the L</Modules and Pragmata> section.
85 [ List each other deprecation as a =head2 entry ]
87 =head1 Performance Enhancements
89 XXX Changes which enhance performance without changing behaviour go here.
90 There may well be none in a stable release.
92 [ List each enhancement as a =item entry ]
102 =head1 Modules and Pragmata
104 XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
105 go here. If Module::CoreList is updated, generate an initial draft of the
106 following sections using F<Porting/corelist-perldelta.pl>. A paragraph summary
107 for important changes should then be added by hand. In an ideal world,
108 dual-life modules would have a F<Changes> file that could be cribbed.
110 [ Within each section, list entries as a =item entry ]
112 =head2 New Modules and Pragmata
122 =head2 Updated Modules and Pragmata
128 L<XXX> has been upgraded from version A.xx to B.yy.
132 =head2 Removed Modules and Pragmata
144 XXX Changes to files in F<pod/> go here. Consider grouping entries by
145 file and be sure to link to the appropriate page, e.g. L<perlfunc>.
147 =head2 New Documentation
149 XXX Changes which create B<new> files in F<pod/> go here.
153 XXX Description of the purpose of the new file here
155 =head2 Changes to Existing Documentation
157 XXX Changes which significantly change existing files in F<pod/> go here.
158 However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
167 XXX Description of the change here
173 The following additions or changes have been made to diagnostic output,
174 including warnings and fatal error messages. For the complete list of
175 diagnostic messages, see L<perldiag>.
177 XXX New or changed warnings emitted by the core's C<C> code go here. Also
178 include any changes in L<perldiag> that reconcile it to the C<C> code.
180 =head2 New Diagnostics
182 XXX Newly added diagnostic messages go under here, separated into New Errors
191 XXX L<message|perldiag/"message">
201 XXX L<message|perldiag/"message">
205 =head2 Changes to Existing Diagnostics
207 XXX Changes (i.e. rewording) of diagnostic messages go here
213 XXX Describe change here
217 =head1 Utility Changes
219 XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go here.
220 Most of these are built within the directory F<utils>.
222 [ List utility changes as a =head2 entry for each utility and =item
223 entries for each change
224 Use L<XXX> with program names to get proper documentation linking. ]
236 =head1 Configuration and Compilation
238 XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
239 go here. Any other changes to the Perl build process should be listed here.
240 However, any platform-specific changes should be listed in the
241 L</Platform Support> section, instead.
243 [ List changes as a =item entry ].
255 XXX Any significant changes to the testing of a freshly built perl should be
256 listed here. Changes which create B<new> files in F<t/> go here as do any
257 large changes to the testing harness (e.g. when parallel testing was added).
258 Changes to existing files in F<t/> aren't worth summarizing, although the bugs
259 that they represent may be covered elsewhere.
261 [ List each test improvement as a =item entry ]
271 =head1 Platform Support
273 XXX Any changes to platform support should be listed in the sections below.
275 [ Within the sections, list each platform as a =item entry with specific
276 changes as paragraphs below it. ]
280 XXX List any platforms that this version of perl compiles on, that previous
281 versions did not. These will either be enabled by new files in the F<hints/>
282 directories, or new subdirectories and F<README> files at the top level of the
287 =item XXX-some-platform
293 =head2 Discontinued Platforms
295 XXX List any platforms that this version of perl no longer compiles on.
299 =item XXX-some-platform
305 =head2 Platform-Specific Notes
307 XXX List any changes for specific platforms. This could include configuration
308 and compilation changes or changes in portability/compatibility. However,
309 changes within modules for platforms should generally be listed in the
310 L</Modules and Pragmata> section.
314 =item XXX-some-platform
320 =head1 Internal Changes
322 XXX Changes which affect the interface available to C<XS> code go here. Other
323 significant internal changes for future core maintainers should be noted as
326 [ List each change as a =item entry ]
336 =head1 Selected Bug Fixes
338 XXX Important bug fixes in the core language are summarized here. Bug fixes in
339 files in F<ext/> and F<lib/> are best summarized in L</Modules and Pragmata>.
341 [ List each fix as a =item entry ]
347 Failing to compile C<use Foo> in an eval could leave a spurious
348 C<BEGIN> subroutine definition, which would produce a "Subroutine
349 BEGIN redefined" warning on the next use of C<use>, or other C<BEGIN>
350 block. [perl #122107]
354 =head1 Known Problems
356 XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
357 tests that had to be C<TODO>ed for the release would be noted here. Unfixed
358 platform specific bugs also go here.
360 [ List each fix as a =item entry ]
370 =head1 Errata From Previous Releases
376 XXX Add anything here that we forgot to add, or were mistaken about, in
377 the perldelta of a previous release.
383 XXX If any significant core contributor has died, we've added a short obituary
386 =head1 Acknowledgements
388 XXX Generate this with:
390 perl Porting/acknowledgements.pl v5.21.2..HEAD
392 =head1 Reporting Bugs
394 If you find what you think is a bug, you might check the articles recently
395 posted to the comp.lang.perl.misc newsgroup and the perl bug database at
396 https://rt.perl.org/ . There may also be information at
397 http://www.perl.org/ , the Perl Home Page.
399 If you believe you have an unreported bug, please run the L<perlbug> program
400 included with your release. Be sure to trim your bug down to a tiny but
401 sufficient test case. Your bug report, along with the output of C<perl -V>,
402 will be sent off to perlbug@perl.org to be analysed by the Perl porting team.
404 If the bug you are reporting has security implications, which make it
405 inappropriate to send to a publicly archived mailing list, then please send it
406 to perl5-security-report@perl.org. This points to a closed subscription
407 unarchived mailing list, which includes all the core committers, who will be
408 able to help assess the impact of issues, figure out a resolution, and help
409 co-ordinate the release of patches to mitigate or fix the problem across all
410 platforms on which Perl is supported. Please only use this address for
411 security issues in the Perl core, not for modules independently distributed on
416 The F<Changes> file for an explanation of how to view exhaustive details on
419 The F<INSTALL> file for how to build Perl.
421 The F<README> file for general stuff.
423 The F<Artistic> and F<Copying> files for copyright information.