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 =head2 New regular expression modifier C</xx>
30 Specifying two C<x> characters to modify a regular expression pattern
31 does everything that a single one does, but additionally TAB and SPACE
32 characters within a bracketed character class are generally ignored and
33 can be added to improve readability, like
34 S<C</[ ^ A-Z d-f p-x ]/xx>>. Details are at
35 L<perlre/E<sol>x and E<sol>xx>.
39 XXX Any security-related notices go here. In particular, any security
40 vulnerabilities closed should be noted here rather than in the
41 L</Selected Bug Fixes> section.
43 [ List each security issue as a =head2 entry ]
45 =head1 Incompatible Changes
47 XXX For a release on a stable branch, this section aspires to be:
49 There are no changes intentionally incompatible with 5.XXX.XXX
50 If any exist, they are bugs, and we request that you submit a
51 report. See L</Reporting Bugs> below.
53 [ List each incompatible change as a =head2 entry ]
57 =head2 String delimiters that aren't stand-alone graphemes are now
60 In order for Perl to eventually allow string delimiters to be Unicode
61 grapheme clusters (which look like a single character, but may be
62 a sequence of several ones), we have to stop allowing a single char
63 delimiter that isn't a grapheme by itself. These are unlikely to exist
64 in actual code, as they would typically display as attached to the
65 character in front of them.
67 =head2 Module removals
69 XXX Remove this section if inapplicable.
71 The following modules will be removed from the core distribution in a
72 future release, and will at that time need to be installed from CPAN.
73 Distributions on CPAN which require these modules will need to list them as
76 The core versions of these modules will now issue C<"deprecated">-category
77 warnings to alert you to this fact. To silence these deprecation warnings,
78 install the modules in question from CPAN.
80 Note that these are (with rare exceptions) fine modules that you are encouraged
81 to continue to use. Their disinclusion from core primarily hinges on their
82 necessity to bootstrapping a fully functional, CPAN-capable Perl installation,
83 not usually on concerns over their design.
89 XXX Note that deprecated modules should be listed here even if they are listed
90 as an updated module in the L</Modules and Pragmata> section.
94 [ List each other deprecation as a =head2 entry ]
96 =head1 Performance Enhancements
98 XXX Changes which enhance performance without changing behaviour go here.
99 There may well be none in a stable release.
101 [ List each enhancement as a =item entry ]
111 =head1 Modules and Pragmata
113 XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
114 go here. If Module::CoreList is updated, generate an initial draft of the
115 following sections using F<Porting/corelist-perldelta.pl>. A paragraph summary
116 for important changes should then be added by hand. In an ideal world,
117 dual-life modules would have a F<Changes> file that could be cribbed.
119 [ Within each section, list entries as a =item entry ]
121 =head2 New Modules and Pragmata
131 =head2 Updated Modules and Pragmata
137 L<XXX> has been upgraded from version A.xx to B.yy.
141 L<re> has been upgraded from version 0.33 to 0.34;
143 This adds support for the new L<C</xx>|perlre/E<sol>x and E<sol>xx>
144 regular expression pattern modifier, and a change to the L<S<C<use re
145 'strict'>>|re/'strict' mode> experimental feature. When S<C<re
146 'strict'>> is enabled, a warning now will be generated for all
147 unescaped uses of the two characters C<}> and C<]> in regular
148 expression patterns (outside bracketed character classes) that are taken
149 literally. This brings them more in line with the C<)> character which
150 is always a metacharacter unless escaped. Being a metacharacter only
151 sometimes, depending on action at a distance, can lead to silently
152 having the pattern mean something quite different than was intended,
153 which the S<C<re 'strict'>> mode is intended to minimize.
157 L<B::Xref> has been upgraded from version 1.05 to 1.06.
161 L<Compress::Raw::Bzip2> has been upgraded from version 2.069 to 2.070.
165 L<Compress::Raw::Zlib> has been upgraded from version 2.069 to 2.070.
169 L<DB_File> has been upgraded from version 1.838 to 1.840.
173 L<Devel::SelfStubber> has been upgraded from version 1.05 to 1.06.
177 L<diagnostics> has been upgraded from version 1.35 to 1.36.
181 L<DynaLoader> has been upgraded from version 1.40 to 1.41.
185 L<Errno> has been upgraded from version 1.27 to 1.28.
189 L<ExtUtils::Embed> has been upgraded from version 1.33 to 1.34.
193 L<I18N::LangTags> has been upgraded from version 0.41 to 0.42.
197 L<lib> has been upgraded from version 0.63 to 0.64.
201 L<Module::CoreList> has been upgraded from version 5.20161220 to 5.20170120.
205 L<OS2::Process> has been upgraded from version 1.11 to 1.12.
209 L<perl5db.pl> has been upgraded from version 1.50 to 1.51.
213 L<Storable> has been upgraded from version 2.59 to 2.61.
217 L<Symbol> has been upgraded from version 1.07 to 1.08.
221 L<Term::ReadLine> has been upgraded from version 1.15 to 1.16.
225 L<Test> has been upgraded from version 1.29 to 1.30.
229 L<threads::shared> has been upgraded from version 1.52 to 1.53.
233 L<Unicode::UCD> has been upgraded from version 0.67 to 0.68.
237 L<VMS::DCLsym> has been upgraded from version 1.07 to 1.08.
241 L<XSLoader> has been upgraded from version 0.24 to 0.26.
245 =head2 Removed Modules and Pragmata
257 XXX Changes to files in F<pod/> go here. Consider grouping entries by
258 file and be sure to link to the appropriate page, e.g. L<perlfunc>.
260 =head2 New Documentation
262 XXX Changes which create B<new> files in F<pod/> go here.
266 XXX Description of the purpose of the new file here
268 =head2 Changes to Existing Documentation
270 XXX Changes which significantly change existing files in F<pod/> go here.
271 However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
280 XXX Description of the change here
286 The following additions or changes have been made to diagnostic output,
287 including warnings and fatal error messages. For the complete list of
288 diagnostic messages, see L<perldiag>.
290 XXX New or changed warnings emitted by the core's C<C> code go here. Also
291 include any changes in L<perldiag> that reconcile it to the C<C> code.
293 =head2 New Diagnostics
295 XXX Newly added diagnostic messages go under here, separated into New Errors
304 XXX L<message|perldiag/"message">
314 XXX L<message|perldiag/"message">
318 =head2 Changes to Existing Diagnostics
320 XXX Changes (i.e. rewording) of diagnostic messages go here
326 XXX Describe change here
330 =head1 Utility Changes
332 XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go here.
333 Most of these are built within the directory F<utils>.
335 [ List utility changes as a =head2 entry for each utility and =item
336 entries for each change
337 Use L<XXX> with program names to get proper documentation linking. ]
349 =head1 Configuration and Compilation
351 XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
352 go here. Any other changes to the Perl build process should be listed here.
353 However, any platform-specific changes should be listed in the
354 L</Platform Support> section, instead.
356 [ List changes as a =item entry ].
362 The C<dtrace> build process has further changes:
368 If the C<-xnolibs> is available, use that so a F<dtrace> perl can be
369 built within a FreeBSD jail.
373 On systems that build a dtrace object file (FreeBSD, Solaris and
374 SystemTap's dtrace emulation), copy the input objects to a separate
375 directory and process them there, and use those objects in the link,
376 since C<dtrace -G> also modifies these objects.
380 Add libelf to the build on FreeBSD 10.x, since dtrace adds references
385 Generate a dummy dtrace_main.o if C<dtrace -G> fails to build it. A
386 default build on Solaris generates probes from the unused inline
387 functions, while they don't on FreeBSD, which causes C<dtrace -G> to
396 You can now disable perl's use of the PERL_HASH_SEED and
397 PERL_PERTURB_KEYS environment variables by configureing perl with
398 C<-Accflags=NO_PERL_HASH_ENV>.
402 You can now disable perl's use of the PERL_HASH_SEED_DEBUG environment
403 variable by configuring perl with
404 C<-Accflags=-DNO_PERL_HASH_SEED_DEBUG>.
410 XXX Any significant changes to the testing of a freshly built perl should be
411 listed here. Changes which create B<new> files in F<t/> go here as do any
412 large changes to the testing harness (e.g. when parallel testing was added).
413 Changes to existing files in F<t/> aren't worth summarizing, although the bugs
414 that they represent may be covered elsewhere.
416 [ List each test improvement as a =item entry ]
426 =head1 Platform Support
428 XXX Any changes to platform support should be listed in the sections below.
430 [ Within the sections, list each platform as a =item entry with specific
431 changes as paragraphs below it. ]
435 XXX List any platforms that this version of perl compiles on, that previous
436 versions did not. These will either be enabled by new files in the F<hints/>
437 directories, or new subdirectories and F<README> files at the top level of the
442 =item XXX-some-platform
448 =head2 Discontinued Platforms
450 XXX List any platforms that this version of perl no longer compiles on.
454 =item XXX-some-platform
460 =head2 Platform-Specific Notes
462 XXX List any changes for specific platforms. This could include configuration
463 and compilation changes or changes in portability/compatibility. However,
464 changes within modules for platforms should generally be listed in the
465 L</Modules and Pragmata> section.
469 =item XXX-some-platform
475 =head1 Internal Changes
477 XXX Changes which affect the interface available to C<XS> code go here. Other
478 significant internal changes for future core maintainers should be noted as
481 [ List each change as a =item entry ]
487 New versions of macros like C<isALPHA_utf8> and C<toLOWER_utf8> have
488 been added, each with the
489 suffix C<_safe>, like C<isSPACE_utf8_safe>. These take an extra
490 parameter, giving an upper limit of how far into the string it is safe
491 to read. Using the old versions could cause attempts to read beyond the
492 end of the input buffer if the UTF-8 is not well-formed, and ther use
493 now raises a deprecation warning. Details are at
494 L<perlapi/Character classification>.
498 Calling macros like C<isALPHA_utf8> on malformed UTF-8 have issued a
499 deprecation warning since Perl v5.18. They now die.
500 Similarly, macros like C<toLOWER_utf8> on malformed UTF-8 now die.
504 Calling the functions C<utf8n_to_uvchr> and its derivatives, while
505 passing a string length of 0 is now asserted against in DEBUGGING
506 builds, and otherwise returns the Unicode REPLACEMENT CHARACTER. If
507 you have nothing to decode, you shouldn't call the decode function.
511 The functions C<utf8n_to_uvchr> and its derivatives now return the
512 Unicode REPLACEMENT CHARACTER if called with UTF-8 that has the overlong
513 malformation, and that malformation is allowed by the input parameters.
514 This malformation is where the UTF-8 looks valid syntactically, but
515 there is a shorter sequence that yields the same code point. This has
516 been forbidden since Unicode version 3.1.
520 The functions C<utf8n_to_uvchr> and its derivatives now accept an input
521 flag to allow the overflow malformation. This malformation is when the
522 UTF-8 may be syntactically valid, but the code point it represents is
523 not capable of being represented in the word length on the platform.
524 What "allowed" means in this case is that the function doesn't return an
525 error, and advances the parse pointer to beyond the UTF-8 in question,
526 but it returns the Unicode REPLACEMENT CHARACTER as the value of the
527 code point (since the real value is not representable).
531 =head1 Selected Bug Fixes
533 XXX Important bug fixes in the core language are summarized here. Bug fixes in
534 files in F<ext/> and F<lib/> are best summarized in L</Modules and Pragmata>.
536 [ List each fix as a =item entry ]
542 Under C<use utf8>, the entire Perl program is now checked that the UTF-8
543 is wellformed. This resolves [perl #126310].
547 The range operator C<..> on strings now handles its arguments correctly when in
548 the scope of the L<< C<unicode_strings>|feature/"The 'unicode_strings' feature" >>
549 feature. The previous behaviour was sufficiently unexpected that we believe no
550 correct program could have made use of it.
554 =head1 Known Problems
556 XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
557 tests that had to be C<TODO>ed for the release would be noted here. Unfixed
558 platform specific bugs also go here.
560 [ List each fix as a =item entry ]
570 =head1 Errata From Previous Releases
576 XXX Add anything here that we forgot to add, or were mistaken about, in
577 the perldelta of a previous release.
583 XXX If any significant core contributor has died, we've added a short obituary
586 =head1 Acknowledgements
588 XXX Generate this with:
590 perl Porting/acknowledgements.pl v5.25.5..HEAD
592 =head1 Reporting Bugs
594 If you find what you think is a bug, you might check the perl bug database
595 at L<https://rt.perl.org/> . There may also be information at
596 L<http://www.perl.org/> , the Perl Home Page.
598 If you believe you have an unreported bug, please run the L<perlbug> program
599 included with your release. Be sure to trim your bug down to a tiny but
600 sufficient test case. Your bug report, along with the output of C<perl -V>,
601 will be sent off to perlbug@perl.org to be analysed by the Perl porting team.
603 If the bug you are reporting has security implications which make it
604 inappropriate to send to a publicly archived mailing list, then see
605 L<perlsec/SECURITY VULNERABILITY CONTACT INFORMATION>
606 for details of how to report the issue.
610 The F<Changes> file for an explanation of how to view exhaustive details on
613 The F<INSTALL> file for how to build Perl.
615 The F<README> file for general stuff.
617 The F<Artistic> and F<Copying> files for copyright information.