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 v5.27.6
12 This document describes differences between the 5.27.5 release and the 5.27.6
15 If you are upgrading from an earlier release such as 5.27.4, first read
16 L<perl5275delta>, which describes differences between 5.27.4 and 5.27.5.
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 an =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 The list of new and updated modules is modified automatically as part of
105 preparing a Perl release, so the only reason to manually add entries here is if
106 you're summarising the important changes in the module update. (Also, if the
107 manually-added details don't match the automatically-generated ones, the
108 release manager will have to investigate the situation carefully.)
110 [ Within each section, list entries as an =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 We have attempted to update the documentation to reflect the changes
158 listed in this document. If you find any we have missed, send email
159 to L<perlbug@perl.org|mailto:perlbug@perl.org>.
161 XXX Changes which significantly change existing files in F<pod/> go here.
162 However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
165 Additionally, the following selected changes have been made:
167 =head3 L<perldiag/Variable length lookbehind not implemented in regex m/%s/>
169 This now gives more ideas as to workarounds to the issue that was
170 introduced in Perl 5.18 (but not documented explicitly in its perldelta)
171 for the fact that some Unicode C</i> rules cause a few sequences such as
175 to be considered variable length, and hence disallowed.
181 XXX Description of the change here
187 The following additions or changes have been made to diagnostic output,
188 including warnings and fatal error messages. For the complete list of
189 diagnostic messages, see L<perldiag>.
191 XXX New or changed warnings emitted by the core's C<C> code go here. Also
192 include any changes in L<perldiag> that reconcile it to the C<C> code.
194 =head2 New Diagnostics
196 XXX Newly added diagnostic messages go under here, separated into New Errors
205 XXX L<message|perldiag/"message">
215 XXX L<message|perldiag/"message">
219 =head2 Changes to Existing Diagnostics
221 XXX Changes (i.e. rewording) of diagnostic messages go here
227 XXX Describe change here
231 =head1 Utility Changes
233 XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go here.
234 Most of these are built within the directory F<utils>.
236 [ List utility changes as a =head2 entry for each utility and =item
237 entries for each change
238 Use L<XXX> with program names to get proper documentation linking. ]
250 =head1 Configuration and Compilation
252 XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
253 go here. Any other changes to the Perl build process should be listed here.
254 However, any platform-specific changes should be listed in the
255 L</Platform Support> section, instead.
257 [ List changes as an =item entry ].
265 =item HAS_BUILTIN_ADD_OVERFLOW
267 =item HAS_BUILTIN_MUL_OVERFLOW
269 =item HAS_BUILTIN_SUB_OVERFLOW
271 =item HAS_THREAD_SAFE_NL_LANGINFO_L
273 =item HAS_LOCALECONV_L
295 XXX Any significant changes to the testing of a freshly built perl should be
296 listed here. Changes which create B<new> files in F<t/> go here as do any
297 large changes to the testing harness (e.g. when parallel testing was added).
298 Changes to existing files in F<t/> aren't worth summarizing, although the bugs
299 that they represent may be covered elsewhere.
301 XXX If there were no significant test changes, say this:
303 Tests were added and changed to reflect the other additions and changes
306 XXX If instead there were significant changes, say this:
308 Tests were added and changed to reflect the other additions and
309 changes in this release. Furthermore, these significant changes were
312 [ List each test improvement as an =item entry ]
322 =head1 Platform Support
324 XXX Any changes to platform support should be listed in the sections below.
326 [ Within the sections, list each platform as an =item entry with specific
327 changes as paragraphs below it. ]
331 XXX List any platforms that this version of perl compiles on, that previous
332 versions did not. These will either be enabled by new files in the F<hints/>
333 directories, or new subdirectories and F<README> files at the top level of the
338 =item XXX-some-platform
344 =head2 Discontinued Platforms
346 XXX List any platforms that this version of perl no longer compiles on.
350 =item XXX-some-platform
356 =head2 Platform-Specific Notes
358 XXX List any changes for specific platforms. This could include configuration
359 and compilation changes or changes in portability/compatibility. However,
360 changes within modules for platforms should generally be listed in the
361 L</Modules and Pragmata> section.
365 =item XXX-some-platform
371 =head1 Internal Changes
373 XXX Changes which affect the interface available to C<XS> code go here. Other
374 significant internal changes for future core maintainers should be noted as
377 [ List each change as an =item entry ]
387 =head1 Selected Bug Fixes
389 XXX Important bug fixes in the core language are summarized here. Bug fixes in
390 files in F<ext/> and F<lib/> are best summarized in L</Modules and Pragmata>.
392 [ List each fix as an =item entry ]
398 The in-place reverse optimisation now correctly strengthens weak
399 references using the L<C<sv_rvunweaken()>|perlapi/sv_rvunweaken>
404 =head1 Known Problems
406 XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
407 tests that had to be C<TODO>ed for the release would be noted here. Unfixed
408 platform specific bugs also go here.
410 [ List each fix as an =item entry ]
420 =head1 Errata From Previous Releases
426 XXX Add anything here that we forgot to add, or were mistaken about, in
427 the perldelta of a previous release.
433 XXX If any significant core contributor has died, we've added a short obituary
436 =head1 Acknowledgements
438 XXX Generate this with:
440 perl Porting/acknowledgements.pl v5.27.5..HEAD
442 =head1 Reporting Bugs
444 If you find what you think is a bug, you might check the perl bug database
445 at L<https://rt.perl.org/> . There may also be information at
446 L<http://www.perl.org/> , the Perl Home Page.
448 If you believe you have an unreported bug, please run the L<perlbug> program
449 included with your release. Be sure to trim your bug down to a tiny but
450 sufficient test case. Your bug report, along with the output of C<perl -V>,
451 will be sent off to perlbug@perl.org to be analysed by the Perl porting team.
453 If the bug you are reporting has security implications which make it
454 inappropriate to send to a publicly archived mailing list, then see
455 L<perlsec/SECURITY VULNERABILITY CONTACT INFORMATION>
456 for details of how to report the issue.
460 If you wish to thank the Perl 5 Porters for the work we had done in Perl 5,
461 you can do so by running the C<perlthanks> program:
465 This will send an email to the Perl 5 Porters list with your show of thanks.
469 The F<Changes> file for an explanation of how to view exhaustive details on
472 The F<INSTALL> file for how to build Perl.
474 The F<README> file for general stuff.
476 The F<Artistic> and F<Copying> files for copyright information.