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 v5.25.9
12 This document describes differences between the 5.25.8 release and the 5.25.9
15 If you are upgrading from an earlier release such as 5.25.7, first read
16 L<perl5258delta>, which describes differences between 5.25.7 and 5.25.8.
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<XXX> has been upgraded from version A.xx to B.yy.
126 L<Module::CoreList> has been upgraded from version 5.20161220 to 5.20170120.
130 =head2 Removed Modules and Pragmata
142 XXX Changes to files in F<pod/> go here. Consider grouping entries by
143 file and be sure to link to the appropriate page, e.g. L<perlfunc>.
145 =head2 New Documentation
147 XXX Changes which create B<new> files in F<pod/> go here.
151 XXX Description of the purpose of the new file here
153 =head2 Changes to Existing Documentation
155 XXX Changes which significantly change existing files in F<pod/> go here.
156 However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
165 XXX Description of the change here
171 The following additions or changes have been made to diagnostic output,
172 including warnings and fatal error messages. For the complete list of
173 diagnostic messages, see L<perldiag>.
175 XXX New or changed warnings emitted by the core's C<C> code go here. Also
176 include any changes in L<perldiag> that reconcile it to the C<C> code.
178 =head2 New Diagnostics
180 XXX Newly added diagnostic messages go under here, separated into New Errors
189 XXX L<message|perldiag/"message">
199 XXX L<message|perldiag/"message">
203 =head2 Changes to Existing Diagnostics
205 XXX Changes (i.e. rewording) of diagnostic messages go here
211 XXX Describe change here
215 =head1 Utility Changes
217 XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go here.
218 Most of these are built within the directory F<utils>.
220 [ List utility changes as a =head2 entry for each utility and =item
221 entries for each change
222 Use L<XXX> with program names to get proper documentation linking. ]
234 =head1 Configuration and Compilation
236 XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
237 go here. Any other changes to the Perl build process should be listed here.
238 However, any platform-specific changes should be listed in the
239 L</Platform Support> section, instead.
241 [ List changes as a =item entry ].
253 XXX Any significant changes to the testing of a freshly built perl should be
254 listed here. Changes which create B<new> files in F<t/> go here as do any
255 large changes to the testing harness (e.g. when parallel testing was added).
256 Changes to existing files in F<t/> aren't worth summarizing, although the bugs
257 that they represent may be covered elsewhere.
259 [ List each test improvement as a =item entry ]
269 =head1 Platform Support
271 XXX Any changes to platform support should be listed in the sections below.
273 [ Within the sections, list each platform as a =item entry with specific
274 changes as paragraphs below it. ]
278 XXX List any platforms that this version of perl compiles on, that previous
279 versions did not. These will either be enabled by new files in the F<hints/>
280 directories, or new subdirectories and F<README> files at the top level of the
285 =item XXX-some-platform
291 =head2 Discontinued Platforms
293 XXX List any platforms that this version of perl no longer compiles on.
297 =item XXX-some-platform
303 =head2 Platform-Specific Notes
305 XXX List any changes for specific platforms. This could include configuration
306 and compilation changes or changes in portability/compatibility. However,
307 changes within modules for platforms should generally be listed in the
308 L</Modules and Pragmata> section.
312 =item XXX-some-platform
318 =head1 Internal Changes
320 XXX Changes which affect the interface available to C<XS> code go here. Other
321 significant internal changes for future core maintainers should be noted as
324 [ List each change as a =item entry ]
330 New versions of macros like C<isALPHA_utf8> have been added, each with the
331 suffix C<_safe>, like C<isSPACE_utf8_safe>. These take an extra
332 parameter, giving an upper limit of how far into the string it is safe
333 to read. Using the old versions could cause attempts to read beyond the
334 end of the input buffer if the UTF-8 is not well-formed, and their use
335 now raises a deprecation warning. Details are at
336 L<perlapi/Character classification>.
340 Calling macros like C<isALPHA_utf8> on malformed UTF-8 have issued a
341 deprecation warning since Perl v5.18. They now die.
342 Similarly, macros like C<toLOWER_utf8> on malformed UTF-8 now die.
346 Calling the functions C<utf8n_to_uvchr> and its derivatives, while
347 passing a string length of 0 is now asserted against in DEBUGGING
348 builds, and otherwise returns the Unicode REPLACEMENT CHARACTER. If
349 you have nothing to decode, you shouldn't call the decode function.
353 The functions C<utf8n_to_uvchr> and its derivatives now return the
354 Unicode REPLACEMENT CHARACTER if called with UTF-8 that has the overlong
355 malformation, and that malformation is allowed by the input parameters.
356 This malformation is where the UTF-8 looks valid syntactically, but
357 there is a shorter sequence that yields the same code point. This has
358 been forbidden since Unicode version 3.1.
362 The functions C<utf8n_to_uvchr> and its derivatives now accept an input
363 flag to allow the overflow malformation. This malformation is when the
364 UTF-8 may be syntactically valid, but the code point it represents is
365 not capable of being represented in the word length on the platform.
366 What "allowed" means in this case is that the function doesn't return an
367 error, and advances the parse pointer to beyond the UTF-8 in question,
368 but it returns the Unicode REPLACEMENT CHARACTER as the value of the
369 code point (since the real value is not representable).
373 =head1 Selected Bug Fixes
375 XXX Important bug fixes in the core language are summarized here. Bug fixes in
376 files in F<ext/> and F<lib/> are best summarized in L</Modules and Pragmata>.
378 [ List each fix as a =item entry ]
384 Under C<use utf8>, the entire Perl program is now checked that the UTF-8
385 is wellformed. This resolves [perl #126310].
389 =head1 Known Problems
391 XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
392 tests that had to be C<TODO>ed for the release would be noted here. Unfixed
393 platform specific bugs also go here.
395 [ List each fix as a =item entry ]
405 =head1 Errata From Previous Releases
411 XXX Add anything here that we forgot to add, or were mistaken about, in
412 the perldelta of a previous release.
418 XXX If any significant core contributor has died, we've added a short obituary
421 =head1 Acknowledgements
423 XXX Generate this with:
425 perl Porting/acknowledgements.pl v5.25.5..HEAD
427 =head1 Reporting Bugs
429 If you find what you think is a bug, you might check the perl bug database
430 at L<https://rt.perl.org/> . There may also be information at
431 L<http://www.perl.org/> , the Perl Home Page.
433 If you believe you have an unreported bug, please run the L<perlbug> program
434 included with your release. Be sure to trim your bug down to a tiny but
435 sufficient test case. Your bug report, along with the output of C<perl -V>,
436 will be sent off to perlbug@perl.org to be analysed by the Perl porting team.
438 If the bug you are reporting has security implications which make it
439 inappropriate to send to a publicly archived mailing list, then see
440 L<perlsec/SECURITY VULNERABILITY CONTACT INFORMATION>
441 for details of how to report the issue.
445 The F<Changes> file for an explanation of how to view exhaustive details on
448 The F<INSTALL> file for how to build Perl.
450 The F<README> file for general stuff.
452 The F<Artistic> and F<Copying> files for copyright information.