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perldelta for PERL_OP_PARENT changes
[perl5.git] / pod / perldelta.pod
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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 v5.21.11
c68523cb 9
238894db 10=head1 DESCRIPTION
c68523cb 11
e5998677 12This document describes differences between the 5.21.10 release and the 5.21.11
238894db 13release.
c68523cb 14
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15If you are upgrading from an earlier release such as 5.21.9, first read
16L<perl52110delta>, which describes differences between 5.21.9 and 5.21.10.
2ec11c70 17
e5998677 18=head1 Notice
ef8784b7 19
e5998677 20XXX Any important notices here
6798c95d 21
e5998677 22=head1 Core Enhancements
6798c95d 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.
cd7bac54 27
e5998677 28[ List each enhancement as a =head2 entry ]
cd7bac54 29
e5998677 30=head1 Security
0939a951 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.
cd7bac54 35
e5998677 36[ List each security issue as a =head2 entry ]
cd7bac54 37
e5998677 38=head1 Incompatible Changes
cd7bac54 39
e5998677 40XXX For a release on a stable branch, this section aspires to be:
83a5d6b6 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.
83a5d6b6 45
e5998677 46[ List each incompatible change as a =head2 entry ]
b9c683b3 47
e5998677 48=head1 Deprecations
b9c683b3 49
e5998677 50XXX Any deprecated features, syntax, modules etc. should be listed here.
b9c683b3 51
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52=head2 Making all warnings fatal is discouraged
53
54The documentation for L<fatal warnings|warnings/Fatal Warnings> notes
55that C<< use warnings FATAL => 'all' >> is discouraged
56and provides stronger language about the risks of fatal warnings
57in general.
58
e5998677 59=head2 Module removals
b05565aa 60
e5998677 61XXX Remove this section if inapplicable.
b05565aa 62
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63The following modules will be removed from the core distribution in a
64future release, and will at that time need to be installed from CPAN.
65Distributions on CPAN which require these modules will need to list them as
66prerequisites.
79116533 67
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68The core versions of these modules will now issue C<"deprecated">-category
69warnings to alert you to this fact. To silence these deprecation warnings,
70install the modules in question from CPAN.
79116533 71
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72Note that these are (with rare exceptions) fine modules that you are encouraged
73to continue to use. Their disinclusion from core primarily hinges on their
74necessity to bootstrapping a fully functional, CPAN-capable Perl installation,
75not usually on concerns over their design.
79116533 76
e5998677 77=over
79116533 78
e5998677 79=item XXX
79116533 80
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81XXX Note that deprecated modules should be listed here even if they are listed
82as an updated module in the L</Modules and Pragmata> section.
79116533 83
e5998677 84=back
79116533 85
e5998677 86[ List each other deprecation as a =head2 entry ]
79116533 87
e5998677 88=head1 Performance Enhancements
79116533 89
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90XXX Changes which enhance performance without changing behaviour go here.
91There may well be none in a stable release.
79116533 92
e5998677 93[ List each enhancement as a =item entry ]
79116533 94
e5998677 95=over 4
79116533
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96
97=item *
98
e5998677 99XXX
79116533
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100
101=back
0939a951 102
e5998677 103=head1 Modules and Pragmata
fea59588 104
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105XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
106go here. If Module::CoreList is updated, generate an initial draft of the
107following sections using F<Porting/corelist-perldelta.pl>. A paragraph summary
108for important changes should then be added by hand. In an ideal world,
109dual-life modules would have a F<Changes> file that could be cribbed.
fea59588 110
e5998677 111[ Within each section, list entries as a =item entry ]
83a5d6b6 112
e5998677 113=head2 New Modules and Pragmata
83a5d6b6 114
e5998677 115=over 4
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116
117=item *
118
e5998677 119XXX
b05565aa 120
e5998677 121=back
83a5d6b6 122
e5998677 123=head2 Updated Modules and Pragmata
83a5d6b6 124
e5998677 125=over 4
e455391f
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126
127=item *
128
79a77127 129L<attributes> has been upgraded from version 0.26 to 0.27.
53902397 130
79a77127
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131=item *
132
133L<Cwd> has been upgraded from version 3.55 to 3.56.
83a5d6b6 134
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135=item *
136
137L<ExtUtils::Miniperl> has been upgraded from version 1.04 to 1.05.
138
139=item *
140
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141L<IO::Socket::IP> has been upgraded from version 0.36 to 0.37.
142
143=item *
144
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145L<Module::CoreList> has been upgraded from version 5.20150320 to 5.20150420.
146
147Updated to cover the latest releases of Perl.
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148
149=item *
150
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151L<perl5db.pl> has been upgraded from 1.48 to 1.49.
152
153The debugger would cause an assertion failure. [perl #124127]
154
155=item *
156
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157L<PerlIO::mmap> has been upgraded from version 0.013 to 0.014.
158
159=item *
160
79a77127 161L<utf8> has been upgraded from version 1.15 to 1.16.
abec5bed 162
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163=item *
164
165L<warnings> has been upgraded from version 1.31 to 1.32.
166
81baec77
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167=item *
168
169L<ExtUtils::ParseXS> has been upgraded from version 3.27 (with certain
170components which were at version 3.25) to version 3.28.
171
e5998677 172=back
83a5d6b6 173
e5998677 174=head2 Removed Modules and Pragmata
83a5d6b6 175
e5998677 176=over 4
83a5d6b6
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177
178=item *
179
e5998677 180XXX
83a5d6b6 181
e5998677 182=back
83a5d6b6 183
e5998677 184=head1 Documentation
83a5d6b6 185
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186XXX Changes to files in F<pod/> go here. Consider grouping entries by
187file and be sure to link to the appropriate page, e.g. L<perlfunc>.
83a5d6b6 188
e5998677 189=head2 New Documentation
b367c45d 190
e5998677 191XXX Changes which create B<new> files in F<pod/> go here.
b367c45d 192
e5998677 193=head3 L<XXX>
b367c45d 194
e5998677 195XXX Description of the purpose of the new file here
338906ce 196
e5998677 197=head2 Changes to Existing Documentation
338906ce 198
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199XXX Changes which significantly change existing files in F<pod/> go here.
200However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
201section.
83a5d6b6 202
e5998677 203=head3 L<XXX>
83a5d6b6 204
e5998677 205=over 4
83a5d6b6
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206
207=item *
208
e5998677 209XXX Description of the change here
83a5d6b6 210
e5998677 211=back
338906ce 212
e5998677 213=head1 Diagnostics
338906ce 214
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215The following additions or changes have been made to diagnostic output,
216including warnings and fatal error messages. For the complete list of
217diagnostic messages, see L<perldiag>.
338906ce 218
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219XXX New or changed warnings emitted by the core's C<C> code go here. Also
220include any changes in L<perldiag> that reconcile it to the C<C> code.
338906ce 221
e5998677 222=head2 New Diagnostics
9409f752 223
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224XXX Newly added diagnostic messages go under here, separated into New Errors
225and New Warnings
9409f752 226
e5998677 227=head3 New Errors
03a97c81 228
e5998677 229=over 4
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230
231=item *
232
e5998677 233XXX L<message|perldiag/"message">
a790e348 234
e5998677 235=back
83a5d6b6 236
e5998677 237=head3 New Warnings
83a5d6b6 238
e5998677 239=over 4
126be117
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240
241=item *
242
e5998677 243XXX L<message|perldiag/"message">
83a5d6b6 244
a9c3e753 245=back
0939a951 246
e5998677 247=head2 Changes to Existing Diagnostics
d2fff9f6 248
e5998677 249XXX Changes (i.e. rewording) of diagnostic messages go here
e329daf3 250
cd7bac54 251=over 4
e329daf3 252
cd7bac54 253=item *
e329daf3 254
e5998677 255XXX Describe change here
83a5d6b6
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256
257=back
258
e5998677 259=head1 Utility Changes
83a5d6b6 260
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261XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go here.
262Most of these are built within the directory F<utils>.
83a5d6b6 263
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264[ List utility changes as a =head2 entry for each utility and =item
265entries for each change
266Use L<XXX> with program names to get proper documentation linking. ]
83a5d6b6 267
e5998677 268=head2 L<XXX>
83a5d6b6
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269
270=over 4
271
272=item *
273
e5998677 274XXX
ba31029d 275
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276=back
277
e5998677 278=head1 Configuration and Compilation
cd7bac54 279
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280XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
281go here. Any other changes to the Perl build process should be listed here.
282However, any platform-specific changes should be listed in the
283L</Platform Support> section, instead.
cd7bac54 284
e5998677 285[ List changes as a =item entry ].
cd7bac54
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286
287=over 4
288
289=item *
290
e5998677 291XXX
cd7bac54
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292
293=back
541e1e0d 294
a9c3e753 295=head1 Testing
cd7bac54 296
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297XXX Any significant changes to the testing of a freshly built perl should be
298listed here. Changes which create B<new> files in F<t/> go here as do any
299large changes to the testing harness (e.g. when parallel testing was added).
300Changes to existing files in F<t/> aren't worth summarizing, although the bugs
301that they represent may be covered elsewhere.
302
303[ List each test improvement as a =item entry ]
304
b5d4d3b9 305=over 4
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306
307=item *
308
e5998677 309XXX
13adb056 310
b5d4d3b9 311=back
391823f2 312
a9c3e753 313=head1 Platform Support
6c8457e9 314
e5998677 315XXX Any changes to platform support should be listed in the sections below.
fdcaecb7 316
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317[ Within the sections, list each platform as a =item entry with specific
318changes as paragraphs below it. ]
ce1e892e 319
e5998677 320=head2 New Platforms
2af7c6b6 321
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322XXX List any platforms that this version of perl compiles on, that previous
323versions did not. These will either be enabled by new files in the F<hints/>
324directories, or new subdirectories and F<README> files at the top level of the
325source tree.
8c847e66 326
2ff1ebfe 327=over 4
d345f487 328
e5998677 329=item XXX-some-platform
d345f487 330
e5998677 331XXX
cd7bac54 332
4dc623f0 333=back
353075a0 334
e5998677 335=head2 Discontinued Platforms
9f122eef 336
e5998677 337XXX List any platforms that this version of perl no longer compiles on.
2ec11c70 338
e5998677 339=over 4
2ec11c70 340
e5998677 341=item XXX-some-platform
2683609f 342
e5998677 343XXX
338906ce 344
4dc623f0 345=back
c7f058f0 346
e5998677 347=head2 Platform-Specific Notes
2bf83140 348
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349XXX List any changes for specific platforms. This could include configuration
350and compilation changes or changes in portability/compatibility. However,
351changes within modules for platforms should generally be listed in the
352L</Modules and Pragmata> section.
041a5927 353
e5998677 354=over 4
041a5927 355
86e0176a 356=item Win32
69e954a5 357
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358F<miniperl.exe> is now built with C<-fno-strict-aliasing>, allowing
35964-bit builds to complete on GCC 4.8. [perl #123976]
360
361C<test-prep> again depends on C<test-prep-gcc> for GCC builds. [perl
362#124221]
69e954a5 363
e5998677 364=back
20b5e916 365
e5998677 366=head1 Internal Changes
d76c14eb 367
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368=over 4
369
370=item *
d76c14eb 371
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3725.21.2 introduced a new build option, C<-DPERL_OP_PARENT>, which causes
373the last C<op_sibling> pointer to refer back to the parent rather than
374being C<NULL>, and where instead a new flag indicates the end of the
375chain. In this release, the new implementation has been revised; in
376particular:
d547bad0 377
e5998677 378=over 4
d547bad0 379
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380=item *
381
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382On C<PERL_OP_PARENT> builds, the C<op_sibling> field has been renamed
383C<op_sibparent> to reflect its new dual purpose. Since the intention is that
384this field should primarily be accessed via macros, this change should be
385transparent for code written to work under C<PERL_OP_PARENT>.
386
387=item *
388
389The newly-introduced C<op_lastsib> flag bit has been renamed C<op_moresib>
390and its logic inverted; i.e. it is initialised to zero in a new op, and is
391changed to 1 when an op gains a sibling.
392
393=item *
394
395The function C<Perl_op_parent> is now only available on C<PERL_OP_PARENT>
396builds. Using it on a plain build will be a compile-timer error.
397
398=item *
399
400Three new macros, C<OpMORESIB_set>, C<OpLASTSIB_set>, C<OpMAYBESIB_set>
401have been added, which are intended to be be a low-level portable way to
402set C<op_sibling> / C<op_sibparent> while also updating C<op_moresib>.
403The first sets the sibling pointer to a new sibling, the second makes the
404op the last sibling, and the third conditionally does the first or second
405action. The C<op_sibling_splice()> function is retained as a higher-level
406interface that can also maintain consistency in the parent at the same time
407(e.g. by updating C<op_first> and C<op_last> where appropriate).
408
409=item *
410
411The macro C<OpSIBLING_set>, added in 5.21.2, has been removed. It didn't
412manipulate C<op_moresib> and has been superseded by C<OpMORESIB_set> et
413al.
414
415=item *
416
417The C<op_sibling_splice> function now accepts a null C<parent> argument
418where the splicing doesn't affect the first or last ops in the sibling
419chain, and thus where the parent doesn't need to be updated accordingly.
420
421=back
422
8a95d307 423
e5998677 424=back
338906ce 425
e5998677 426=head1 Selected Bug Fixes
338906ce 427
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428XXX Important bug fixes in the core language are summarized here. Bug fixes in
429files in F<ext/> and F<lib/> are best summarized in L</Modules and Pragmata>.
338906ce 430
e5998677 431[ List each fix as a =item entry ]
338906ce 432
e5998677 433=over 4
338906ce
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434
435=item *
436
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437C<pack("D", $x)> and C<pack("F", $x)> now zero the padding on x86 long
438double builds. GCC 4.8 and later, under some build options, would
439either overwrite the zero-initialized padding, or bypass the
440initialized buffer entirely. This caused F<op/pack.t> to fail. [perl
441#123971]
2f304be9 442
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443=item *
444
445Extending an array cloned from a parent thread could result in
446"Modification of a read-only value attempted" errors when attempting
447to modify the new elements. [perl #124127]
448
a9c3e753 449=back
ea13b07e 450
a9c3e753 451=head1 Known Problems
b65adbec 452
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453XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
454tests that had to be C<TODO>ed for the release would be noted here. Unfixed
455platform specific bugs also go here.
b94c7836 456
e5998677 457[ List each fix as a =item entry ]
ce1e892e
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458
459=over 4
460
461=item *
462
e5998677 463XXX
ce1e892e 464
e5998677 465=back
ce1e892e 466
e5998677 467=head1 Errata From Previous Releases
ce1e892e 468
e5998677 469=over 4
ce1e892e 470
e5998677 471=item *
ce1e892e 472
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473XXX Add anything here that we forgot to add, or were mistaken about, in
474the perldelta of a previous release.
ce1e892e 475
a9c3e753 476=back
e3e8f263 477
e5998677 478=head1 Obituary
0d42058e 479
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480XXX If any significant core contributor has died, we've added a short obituary
481here.
0d42058e 482
e5998677 483=head1 Acknowledgements
0d42058e 484
e5998677 485XXX Generate this with:
0d42058e 486
e5998677 487 perl Porting/acknowledgements.pl v5.21.10..HEAD
f5b73711 488
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489=head1 Reporting Bugs
490
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491If you find what you think is a bug, you might check the articles recently
492posted to the comp.lang.perl.misc newsgroup and the perl bug database at
e5998677
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493https://rt.perl.org/ . There may also be information at
494http://www.perl.org/ , the Perl Home Page.
44691e6f 495
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496If you believe you have an unreported bug, please run the L<perlbug> program
497included with your release. Be sure to trim your bug down to a tiny but
498sufficient test case. Your bug report, along with the output of C<perl -V>,
499will be sent off to perlbug@perl.org to be analysed by the Perl porting team.
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500
501If the bug you are reporting has security implications, which make it
e08634c5
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502inappropriate to send to a publicly archived mailing list, then please send it
503to perl5-security-report@perl.org. This points to a closed subscription
504unarchived mailing list, which includes all the core committers, who will be
505able to help assess the impact of issues, figure out a resolution, and help
f9001595 506co-ordinate the release of patches to mitigate or fix the problem across all
e08634c5
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507platforms on which Perl is supported. Please only use this address for
508security issues in the Perl core, not for modules independently distributed on
509CPAN.
44691e6f
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510
511=head1 SEE ALSO
512
e08634c5
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513The F<Changes> file for an explanation of how to view exhaustive details on
514what changed.
44691e6f
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515
516The F<INSTALL> file for how to build Perl.
517
518The F<README> file for general stuff.
519
520The F<Artistic> and F<Copying> files for copyright information.
521
522=cut