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1=encoding utf8
2
3=head1 NAME
4
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5[ this is a template for a new perldelta file. Any text flagged as XXX needs
6to be processed before release. ]
7
8perldelta - what is new for perl v5.21.4
c68523cb 9
238894db 10=head1 DESCRIPTION
c68523cb 11
39c4a6cf 12This document describes differences between the 5.21.3 release and the 5.21.4
238894db 13release.
c68523cb 14
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15If you are upgrading from an earlier release such as 5.21.2, first read
16L<perl5213delta>, which describes differences between 5.21.2 and 5.21.3.
7065301c 17
39c4a6cf 18=head1 Notice
7e957246 19
39c4a6cf 20XXX Any important notices here
7e957246 21
39c4a6cf 22=head1 Core Enhancements
f88f10f5 23
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24XXX New core language features go here. Summarize user-visible core language
25enhancements. Particularly prominent performance optimisations could go
26here, but most should go in the L</Performance Enhancements> section.
21f3b41e 27
39c4a6cf 28[ List each enhancement as a =head2 entry ]
f88f10f5 29
0346c3a9 30=head1 Security
7e957246 31
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32XXX Any security-related notices go here. In particular, any security
33vulnerabilities closed should be noted here rather than in the
34L</Selected Bug Fixes> section.
13900f93 35
39c4a6cf 36[ List each security issue as a =head2 entry ]
8bdb3f93 37
13900f93 38=head1 Incompatible Changes
8bdb3f93 39
39c4a6cf 40XXX For a release on a stable branch, this section aspires to be:
1178d2cf 41
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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.
1178d2cf 45
39c4a6cf 46[ List each incompatible change as a =head2 entry ]
f6f3144e 47
39c4a6cf 48=head1 Deprecations
7065301c 49
39c4a6cf 50XXX Any deprecated features, syntax, modules etc. should be listed here.
7065301c 51
39c4a6cf 52=head2 Module removals
b3e82ed1 53
39c4a6cf 54XXX Remove this section if inapplicable.
ca58223b 55
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56The following modules will be removed from the core distribution in a
57future release, and will at that time need to be installed from CPAN.
58Distributions on CPAN which require these modules will need to list them as
59prerequisites.
ca58223b 60
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61The core versions of these modules will now issue C<"deprecated">-category
62warnings to alert you to this fact. To silence these deprecation warnings,
63install the modules in question from CPAN.
23b03637 64
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65Note that these are (with rare exceptions) fine modules that you are encouraged
66to continue to use. Their disinclusion from core primarily hinges on their
67necessity to bootstrapping a fully functional, CPAN-capable Perl installation,
68not usually on concerns over their design.
23b03637 69
39c4a6cf 70=over
85e8fb10 71
39c4a6cf 72=item XXX
85e8fb10 73
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74XXX Note that deprecated modules should be listed here even if they are listed
75as an updated module in the L</Modules and Pragmata> section.
134f90c2 76
39c4a6cf 77=back
134f90c2 78
39c4a6cf 79[ List each other deprecation as a =head2 entry ]
ff433f2d 80
39c4a6cf 81=head1 Performance Enhancements
ff433f2d 82
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83XXX Changes which enhance performance without changing behaviour go here.
84There may well be none in a stable release.
134f90c2 85
39c4a6cf 86[ List each enhancement as a =item entry ]
134f90c2 87
39c4a6cf 88=over 4
7d19f6a1 89
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90=item *
91
39c4a6cf 92XXX
55e8b286 93
39c4a6cf 94=back
55e8b286 95
39c4a6cf 96=head1 Modules and Pragmata
d99849ae 97
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98XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
99go here. If Module::CoreList is updated, generate an initial draft of the
100following sections using F<Porting/corelist-perldelta.pl>. A paragraph summary
101for important changes should then be added by hand. In an ideal world,
102dual-life modules would have a F<Changes> file that could be cribbed.
d99849ae 103
39c4a6cf 104[ Within each section, list entries as a =item entry ]
ff433f2d 105
39c4a6cf 106=head2 New Modules and Pragmata
ff433f2d 107
39c4a6cf 108=over 4
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109
110=item *
111
39c4a6cf 112XXX
0bb39c26 113
39c4a6cf 114=back
0bb39c26 115
39c4a6cf 116=head2 Updated Modules and Pragmata
9c97a342 117
39c4a6cf 118=over 4
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119
120=item *
121
39c4a6cf 122L<XXX> has been upgraded from version A.xx to B.yy.
6ab3666b 123
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124=item *
125
126L<File::Find> has been upgraded from version 1.27 to 1.28.
39091b75 127
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128C<find()> and C<finddepth()> will now warn if passed inappropriate or
129misspelled options.
130
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131=item *
132
133L<B::Concise> has been upgraded from version 0.992 to 0.993.
134
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135
136=item *
137
138L<ExtUtils::CBuilder> has been upgraded from version 0.280216 to 0.280219.
139[perl #122675].
140
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141=item *
142
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143L<ExtUtils::Manifest> has been upgraded from version 1.65 to 1.66.
144[perl #122415].
145
146=item *
147
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148L<HTTP::Tiny> has been upgraded from version 0.047 to 0.048.
149
150=item *
151
152L<Module::CoreList> has been upgraded from version 5.021003 to 5.021004.
153
154=item *
155
156L<POSIX> has been upgraded from version 1.42 to 1.43.
157
158=item *
159
160L<Pod::Perldoc> has been upgraded from version 3.23 to 3.24.
161
162=item *
163
164L<constant> has been upgraded from version 1.31 to 1.32.
165
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166It now accepts fully-qualified constant names, allowing constants to be
167defined in packages other than the caller.
168
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169=item *
170
171L<threads> has been upgraded from version 1.95 to 1.96.
172
39c4a6cf 173=back
9c97a342 174
39c4a6cf 175=head2 Removed Modules and Pragmata
d99849ae 176
39c4a6cf 177=over 4
d99849ae 178
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179=item *
180
39c4a6cf 181XXX
ff433f2d 182
13900f93 183=back
aac7f82f 184
13900f93 185=head1 Documentation
aac7f82f 186
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187XXX Changes to files in F<pod/> go here. Consider grouping entries by
188file and be sure to link to the appropriate page, e.g. L<perlfunc>.
6d9b7c7c 189
39c4a6cf 190=head2 New Documentation
2a395b86 191
39c4a6cf 192XXX Changes which create B<new> files in F<pod/> go here.
2a395b86 193
39c4a6cf 194=head3 L<XXX>
2a395b86 195
39c4a6cf 196XXX Description of the purpose of the new file here
2a395b86 197
39c4a6cf 198=head2 Changes to Existing Documentation
2a395b86 199
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200XXX Changes which significantly change existing files in F<pod/> go here.
201However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
202section.
203
204=head3 L<XXX>
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205
206=over 4
207
208=item *
209
39c4a6cf 210XXX Description of the change here
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211
212=back
213
39c4a6cf 214=head1 Diagnostics
2a395b86 215
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216The following additions or changes have been made to diagnostic output,
217including warnings and fatal error messages. For the complete list of
218diagnostic messages, see L<perldiag>.
2a395b86 219
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220XXX New or changed warnings emitted by the core's C<C> code go here. Also
221include any changes in L<perldiag> that reconcile it to the C<C> code.
2a395b86 222
39c4a6cf 223=head2 New Diagnostics
0f4a583b 224
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225XXX Newly added diagnostic messages go under here, separated into New Errors
226and New Warnings
2a395b86 227
39c4a6cf 228=head3 New Errors
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229
230=over 4
231
232=item *
233
39c4a6cf 234XXX L<message|perldiag/"message">
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235
236=back
237
39c4a6cf 238=head3 New Warnings
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239
240=over 4
241
242=item *
243
39c4a6cf 244XXX L<message|perldiag/"message">
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245
246=back
6d9b7c7c 247
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248=head2 Changes to Existing Diagnostics
249
250XXX Changes (i.e. rewording) of diagnostic messages go here
7f55cec0 251
13900f93 252=over 4
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253
254=item *
255
39c4a6cf 256XXX Describe change here
aac7f82f 257
13900f93 258=back
aac7f82f 259
39c4a6cf 260=head1 Utility Changes
091fed7c 261
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262XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go here.
263Most of these are built within the directory F<utils>.
902c1f75 264
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265[ List utility changes as a =head2 entry for each utility and =item
266entries for each change
267Use L<XXX> with program names to get proper documentation linking. ]
2901561d 268
39c4a6cf 269=head2 L<XXX>
4594cf53 270
13900f93 271=over 4
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272
273=item *
274
39c4a6cf 275XXX
a1d26ccd 276
39c4a6cf 277=back
a1d26ccd 278
39c4a6cf 279=head1 Configuration and Compilation
7065301c 280
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281XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
282go here. Any other changes to the Perl build process should be listed here.
283However, any platform-specific changes should be listed in the
284L</Platform Support> section, instead.
58f25ac1 285
39c4a6cf 286[ List changes as a =item entry ].
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287
288=over 4
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289
290=item *
291
39c4a6cf 292XXX
a5873648 293
39c4a6cf 294=back
a5873648 295
39c4a6cf 296=head1 Testing
a5873648 297
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298XXX Any significant changes to the testing of a freshly built perl should be
299listed here. Changes which create B<new> files in F<t/> go here as do any
300large changes to the testing harness (e.g. when parallel testing was added).
301Changes to existing files in F<t/> aren't worth summarizing, although the bugs
302that they represent may be covered elsewhere.
a5873648 303
39c4a6cf 304[ List each test improvement as a =item entry ]
a5873648 305
39c4a6cf 306=over 4
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307
308=item *
309
39c4a6cf 310XXX
a5873648 311
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312=back
313
39c4a6cf 314=head1 Platform Support
b10906fb 315
39c4a6cf 316XXX Any changes to platform support should be listed in the sections below.
b10906fb 317
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318[ Within the sections, list each platform as a =item entry with specific
319changes as paragraphs below it. ]
b10906fb 320
39c4a6cf 321=head2 New Platforms
b10906fb 322
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323XXX List any platforms that this version of perl compiles on, that previous
324versions did not. These will either be enabled by new files in the F<hints/>
325directories, or new subdirectories and F<README> files at the top level of the
326source tree.
13900f93 327
7065301c 328=over 4
24a38d90 329
39c4a6cf 330=item XXX-some-platform
24a38d90 331
39c4a6cf 332XXX
bb076206 333
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334=back
335
39c4a6cf 336=head2 Discontinued Platforms
097675bf 337
39c4a6cf 338XXX List any platforms that this version of perl no longer compiles on.
b3211734 339
6e97d65d 340=over 4
b3211734 341
39c4a6cf 342=item XXX-some-platform
7065301c 343
39c4a6cf 344XXX
13900f93 345
39c4a6cf 346=back
7d0ccdba 347
39c4a6cf 348=head2 Platform-Specific Notes
7d0ccdba 349
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350XXX List any changes for specific platforms. This could include configuration
351and compilation changes or changes in portability/compatibility. However,
352changes within modules for platforms should generally be listed in the
353L</Modules and Pragmata> section.
6e97d65d 354
39c4a6cf 355=over 4
6e97d65d 356
39c4a6cf 357=item XXX-some-platform
6e97d65d 358
39c4a6cf 359XXX
7d0ccdba 360
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361=back
362
363=head1 Internal Changes
364
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365XXX Changes which affect the interface available to C<XS> code go here. Other
366significant internal changes for future core maintainers should be noted as
367well.
c9fcb674 368
39c4a6cf 369[ List each change as a =item entry ]
a835cd47 370
39c4a6cf 371=over 4
c1284011 372
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373=item *
374
07ec6dc6 375The parser no longer gets confused by C<\U=> within a double-quoted string.
2c9f1bc6 376It used to roduce a syntax error, but now compiles it correctly.
07ec6dc6 377[perl #80368]
1c43698b 378
6d9b7c7c 379=back
c1284011 380
6d9b7c7c 381=head1 Selected Bug Fixes
375f5f06 382
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383XXX Important bug fixes in the core language are summarized here. Bug fixes in
384files in F<ext/> and F<lib/> are best summarized in L</Modules and Pragmata>.
385
386[ List each fix as a =item entry ]
387
0346c3a9 388=over 4
375f5f06 389
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390=item *
391
39c4a6cf 392XXX
2884baee 393
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394=item *
395
396Compile-time checking of constant dereferencing (e.g.,
397C<< my_constant->() >>) has been removed, since it was not taking
398overloading into account. [perl #69456] [perl #122607]
399
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400=item *
401
402Constant dereferencing now works correctly for typeglob constants.
403Previously the glob was stringified and its name looked up. Now the glob
404itself is used. [perl #69456]
405
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406=item *
407
408When parsing a funny character ($ @ % &) followed by braces, the parser no
409longer tries to guess whether it is a block or a hash constructor (causing
410a syntax error when it guesses the latter), since it can only be a block.
411
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412=item *
413
414C<undef $reference> now frees the referent immediately, instead of hanging
415on to it until the next statement. [perl #122556]
416
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417=item *
418
419Various cases where the name of a sub is used (autoload, overloading, error
420messages) used to crash for lexical subs, but have been fixed.
421
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422=item *
423
424Bareword lookup now tries to avoid vivifying packages if it turns out the
425bareword is not going to be a subroutine name.
426
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427=item *
428
429Compilation of anonymous constants (e.g., C<sub () { 3 }>) no longer
430deletes any subroutine named C<__ANON__> in the current package. Not only
431was C<*__ANON__{CODE}> cleared, but there was a memory leak, too. This bug
432goes back to perl 5.8.0.
433
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434=item *
435
436Stub declarations like C<sub f;> and C<sub f ();> no longer wipe out
437constants of the same name declared by C<use constant>. This bug was
438introduced in perl 5.10.0.
439
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440=item *
441
442Under some conditions a warning raised in compilation of regular
443expression patterns could be displayed multiple times. This is now
444fixed.
445
39c4a6cf 446=back
b756670b 447
39c4a6cf 448=head1 Known Problems
b756670b 449
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450XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
451tests that had to be C<TODO>ed for the release would be noted here. Unfixed
452platform specific bugs also go here.
e917e94e 453
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454[ List each fix as a =item entry ]
455
456=over 4
e917e94e 457
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458=item *
459
39c4a6cf 460XXX
26dd5fd6 461
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462=back
463
39c4a6cf 464=head1 Errata From Previous Releases
e831f11a 465
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466=over 4
467
468=item *
ff433f2d 469
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470XXX Add anything here that we forgot to add, or were mistaken about, in
471the perldelta of a previous release.
ff433f2d 472
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473=back
474
475=head1 Obituary
ff433f2d 476
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477XXX If any significant core contributor has died, we've added a short obituary
478here.
ff433f2d 479
39c4a6cf 480=head1 Acknowledgements
ff433f2d 481
39c4a6cf 482XXX Generate this with:
e831f11a 483
39c4a6cf 484 perl Porting/acknowledgements.pl v5.21.3..HEAD
f5b73711 485
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486=head1 Reporting Bugs
487
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488If you find what you think is a bug, you might check the articles recently
489posted to the comp.lang.perl.misc newsgroup and the perl bug database at
238894db 490https://rt.perl.org/ . There may also be information at
7ef8b31d 491http://www.perl.org/ , the Perl Home Page.
44691e6f 492
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493If you believe you have an unreported bug, please run the L<perlbug> program
494included with your release. Be sure to trim your bug down to a tiny but
495sufficient test case. Your bug report, along with the output of C<perl -V>,
496will be sent off to perlbug@perl.org to be analysed by the Perl porting team.
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497
498If the bug you are reporting has security implications, which make it
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499inappropriate to send to a publicly archived mailing list, then please send it
500to perl5-security-report@perl.org. This points to a closed subscription
501unarchived mailing list, which includes all the core committers, who will be
502able to help assess the impact of issues, figure out a resolution, and help
f9001595 503co-ordinate the release of patches to mitigate or fix the problem across all
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504platforms on which Perl is supported. Please only use this address for
505security issues in the Perl core, not for modules independently distributed on
506CPAN.
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507
508=head1 SEE ALSO
509
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510The F<Changes> file for an explanation of how to view exhaustive details on
511what changed.
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512
513The F<INSTALL> file for how to build Perl.
514
515The F<README> file for general stuff.
516
517The F<Artistic> and F<Copying> files for copyright information.
518
519=cut