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 v5.21.10
12 This document describes differences between the 5.21.9 release and the 5.21.10
15 If you are upgrading from an earlier release such as 5.21.8, first read
16 L<perl5219delta>, which describes differences between 5.21.8 and 5.21.9.
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 ]
93 C<utf8::native_to_unicode()> and
94 C<utf8::unicode_to_native()> (see L<utf8>)
95 are now optimized out on ASCII platforms.
96 There is now not even a minimal performance hit in writing code portable
97 between ASCII and EBCDIC platforms.
101 =head1 Modules and Pragmata
103 XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
104 go here. If Module::CoreList is updated, generate an initial draft of the
105 following sections using F<Porting/corelist-perldelta.pl>. A paragraph summary
106 for important changes should then be added by hand. In an ideal world,
107 dual-life modules would have a F<Changes> file that could be cribbed.
109 [ Within each section, list entries as a =item entry ]
111 =head2 New Modules and Pragmata
121 =head2 Updated Modules and Pragmata
127 L<B> has been upgraded from version 1.56 to 1.57.
131 L<B::Deparse> has been upgraded from version 1.33 to 1.34.
133 Deparse C<$#_> as that instead of as C<$#{_}>. [perl #123947]
137 L<CPAN> has been upgraded from version 2.05 to 2.10.
143 Add support for C<Cwd::getdcwd()> and introduce workaround for a misbehaviour
144 seen on Strawberry Perl 5.20.1.
148 Fix C<chdir()> after building dependencies bug.
152 Introduce experimental support for plugins/hooks.
156 Integrate the App::Cpan sources.
160 Do not check recursion on optional dependencies.
164 Sanity check META.yml to contain a hash.
165 L<[cpan #95271]|https://rt.cpan.org/Ticket/Display.html?id=95271>
171 L<CPAN::Meta> has been upgraded from version 2.143240 to 2.150001.
175 L<Data::Dumper> has been upgraded from version 2.157 to 2.158.
179 L<DynaLoader> has been upgraded from version 1.31 to 1.32.
183 L<Encode> has been upgraded from version 2.70 to 2.72.
187 L<encoding> has been upgraded from version 2.13 to 2.14.
191 L<Getopt::Long> has been upgraded from version 2.43 to 2.45.
195 L<locale> has been upgraded from version 1.05 to 1.06.
199 L<Locale::Codes> has been upgraded from version 3.33 to 3.34.
203 L<Module::CoreList> has been reverted from version 5.20150220 to 5.20150320.
207 L<Pod::Functions> has been upgraded from version 1.08 to 1.09.
211 L<POSIX> has been upgraded from version 1.51 to 1.52.
215 L<re> has been upgraded from version 0.31 to 0.32.
219 L<Test::Simple> has been reverted from version 1.301001_098 to 1.001014.
223 L<Text::Balanced> has been upgraded from version 2.02 to 2.03.
225 No changes to installed files other than the version bump.
229 L<Text::ParseWords> has been upgraded from version 3.29 to 3.30.
233 L<threads> has been upgraded from version 1.96_001 to 2.01.
237 L<utf8> has been upgraded from version 1.14 to 1.15.
241 L<XS::APItest> has been upgraded from version 0.70 to 0.71.
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 Documentation has been added regarding the special floating point values C<Inf>
285 =head3 L<perlexperiment>
291 Removed note about C<\s> matching C<VT> now that it is no longer experimental.
295 Added note that C<use re 'strict'> has been introduced experimentally.
305 The documentation of what to expect to see in future maintenance releases has
306 been updated. Essentially the same types of changes will be included as before
307 but with fewer changes that don't affect the installation or execution of perl.
313 The following additions or changes have been made to diagnostic output,
314 including warnings and fatal error messages. For the complete list of
315 diagnostic messages, see L<perldiag>.
317 XXX New or changed warnings emitted by the core's C<C> code go here. Also
318 include any changes in L<perldiag> that reconcile it to the C<C> code.
320 =head2 New Diagnostics
322 XXX Newly added diagnostic messages go under here, separated into New Errors
331 L<Invalid quantifier in {,} in regex; marked by <-- HERE in mE<sol>%sE<sol>|perldiag/"Invalid quantifier in {,} in regex; marked by <-- HERE in m/%s/">
333 (F) The pattern looks like a {min,max} quantifier, but the min or max could not
334 be parsed as a valid number - either it has leading zeroes, or it represents
335 too big a number to cope with. The S<<-- HERE> shows where in the regular
336 expression the problem was discovered. See L<perlre>.
346 XXX L<message|perldiag/"message">
350 =head2 Changes to Existing Diagnostics
352 XXX Changes (i.e. rewording) of diagnostic messages go here
358 XXX Describe change here
362 =head1 Utility Changes
364 XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go here.
365 Most of these are built within the directory F<utils>.
367 [ List utility changes as a =head2 entry for each utility and =item
368 entries for each change
369 Use L<XXX> with program names to get proper documentation linking. ]
381 =head1 Configuration and Compilation
383 XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
384 go here. Any other changes to the Perl build process should be listed here.
385 However, any platform-specific changes should be listed in the
386 L</Platform Support> section, instead.
388 [ List changes as a =item entry ].
400 XXX Any significant changes to the testing of a freshly built perl should be
401 listed here. Changes which create B<new> files in F<t/> go here as do any
402 large changes to the testing harness (e.g. when parallel testing was added).
403 Changes to existing files in F<t/> aren't worth summarizing, although the bugs
404 that they represent may be covered elsewhere.
406 [ List each test improvement as a =item entry ]
412 Tests for performance issues have been added in the file F<t/perf/taint.t>.
416 =head1 Platform Support
418 XXX Any changes to platform support should be listed in the sections below.
420 [ Within the sections, list each platform as a =item entry with specific
421 changes as paragraphs below it. ]
425 XXX List any platforms that this version of perl compiles on, that previous
426 versions did not. These will either be enabled by new files in the F<hints/>
427 directories, or new subdirectories and F<README> files at the top level of the
432 =item XXX-some-platform
438 =head2 Discontinued Platforms
440 XXX List any platforms that this version of perl no longer compiles on.
444 =item XXX-some-platform
450 =head2 Platform-Specific Notes
452 XXX List any changes for specific platforms. This could include configuration
453 and compilation changes or changes in portability/compatibility. However,
454 changes within modules for platforms should generally be listed in the
455 L</Modules and Pragmata> section.
459 =item XXX-some-platform
465 =head1 Internal Changes
467 XXX Changes which affect the interface available to C<XS> code go here. Other
468 significant internal changes for future core maintainers should be noted as
471 [ List each change as a =item entry ]
481 =head1 Selected Bug Fixes
483 XXX Important bug fixes in the core language are summarized here. Bug fixes in
484 files in F<ext/> and F<lib/> are best summarized in L</Modules and Pragmata>.
486 [ List each fix as a =item entry ]
492 Repeated global pattern matches in scalar context on large tainted
493 strings were exponentially slow depending on the current match
494 position in the string. [perl #123202]
498 =head1 Known Problems
500 XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
501 tests that had to be C<TODO>ed for the release would be noted here. Unfixed
502 platform specific bugs also go here.
504 [ List each fix as a =item entry ]
514 =head1 Errata From Previous Releases
520 XXX Add anything here that we forgot to add, or were mistaken about, in
521 the perldelta of a previous release.
527 XXX If any significant core contributor has died, we've added a short obituary
530 =head1 Acknowledgements
532 XXX Generate this with:
534 perl Porting/acknowledgements.pl v5.21.9..HEAD
536 =head1 Reporting Bugs
538 If you find what you think is a bug, you might check the articles recently
539 posted to the comp.lang.perl.misc newsgroup and the perl bug database at
540 https://rt.perl.org/ . There may also be information at
541 http://www.perl.org/ , the Perl Home Page.
543 If you believe you have an unreported bug, please run the L<perlbug> program
544 included with your release. Be sure to trim your bug down to a tiny but
545 sufficient test case. Your bug report, along with the output of C<perl -V>,
546 will be sent off to perlbug@perl.org to be analysed by the Perl porting team.
548 If the bug you are reporting has security implications, which make it
549 inappropriate to send to a publicly archived mailing list, then please send it
550 to perl5-security-report@perl.org. This points to a closed subscription
551 unarchived mailing list, which includes all the core committers, who will be
552 able to help assess the impact of issues, figure out a resolution, and help
553 co-ordinate the release of patches to mitigate or fix the problem across all
554 platforms on which Perl is supported. Please only use this address for
555 security issues in the Perl core, not for modules independently distributed on
560 The F<Changes> file for an explanation of how to view exhaustive details on
563 The F<INSTALL> file for how to build Perl.
565 The F<README> file for general stuff.
567 The F<Artistic> and F<Copying> files for copyright information.