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1=encoding utf8
2
8ebb9810 3=for release_engineer
df91fef1 4* changelogged up to 38ef960
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5* the mauve module will not be part of the release, so it's not changelogged
6yet. it also added some new api functions. those aren't covered either, as they
7might go away again in case mauve gets rolled back for 5.13.5.
8
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9=head1 NAME
10
11[ this is a template for a new perldelta file. Any text flagged as
12XXX needs to be processed before release. ]
13
14perldelta - what is new for perl v5.13.5
15
16=head1 DESCRIPTION
17
18This document describes differences between the 5.13.4 release and
19the 5.13.5 release.
20
21If you are upgrading from an earlier release such as 5.13.3, first read
22L<perl5134delta>, which describes differences between 5.13.3 and
235.13.4.
24
25=head1 Notice
26
27XXX Any important notices here
28
29=head1 Core Enhancements
30
31XXX New core language features go here. Summarise user-visible core language
32enhancements. Particularly prominent performance optimisations could go
33here, but most should go in the L</Performance Enhancements> section.
34
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35=head2 Adjacent pairs of nextstate opcodes are now optimized away
36
37Previously, in code such as
38
39 use constant DEBUG => 0;
40
41 sub GAK {
42 warn if DEBUG;
43 print "stuff\n";
44 }
45
46the ops for C<warn if DEBUG;> would be folded to a C<null> op (C<ex-const>), but
47the C<nextstate> op would remain, resulting in a runtime op dispatch of
48C<nextstate>, C<nextstate>, ...
49
50The execution of a sequence of C<nexstate> ops is indistinguishable from just
51the last C<nextstate> op, so teach the peephole optimiser to eliminate the first
52of a pair of C<nextstate> ops. (Except where the first carries a label, as
53labels mustn't be eliminated by the optimiser, and label usage isn't
54conclusively known at compile time.)
4c793fe3 55
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56=head2 API function to parse statements
57
58The C<parse_fullstmt> function has been added to allow parsing of a single
59complete Perl statement. See L<perlapi> for details.
60
61=head2 API functions for accessing the runtime hinthash
62
63A new C API for introspecting the hinthash C<%^H> at runtime has been added. See
64C<cop_hints_2hv>, C<cop_hints_fetchpvn>, C<cop_hints_fetchpvs>, and
65C<cop_hints_fetchsv> in L<perlapi> for details.
66
67=head2 C interface to C<caller()>
68
69The C<caller_cx> function has been added as an XSUB-writer's equivalent of
70C<caller()>. See L<perlapi> for details.
71
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72=head1 Security
73
74XXX Any security-related notices go here. In particular, any security
75vulnerabilities closed should be noted here rather than in the
76L</Selected Bug Fixes> section.
77
78[ List each security issue as a =head2 entry ]
79
80=head1 Incompatible Changes
81
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82=head2 Magic Variables Outside the Main Package
83
84In previous versions of perl, magic variables like C<$!>, C<%SIG>, etc. would
85'leak' into other packages. So C<%foo::SIG> could be used to access signals,
86C<${"foo::!"}> (with strict mode off) to access C's C<errno>, etc.
87
88This was a bug, or an 'unintentional' feature, which caused various ill
89effects, such as signal handlers being wiped when modules were loaded, etc.
90
91This has been fixed (or the feature has been removed, depending on how you
92see it).
93
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94=head2 Smart-matching against array slices
95
96Previously, the following code resulted in a successful match:
97
98 my @a = qw(a y0 z);
99 my @b = qw(a x0 z);
100 $a[0 .. $#b] ~~ @b;
101
102This odd behaviour has now been fixed [perl #77468].
103
d6747b7a 104=head2 C API changes
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106The first argument of the C API function C<Perl_fetch_cop_label> has changed
107from C<struct refcounted he *> to C<COP *>, to better insulate the user from
108implementation details.
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110This API function was marked as "may change", and likely isn't in use outside
111the core. (Neither an unpacked CPAN, nor Google's codesearch, finds any other
112references to it.)
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113
114=head1 Deprecations
115
116XXX Any deprecated features, syntax, modules etc. should be listed here.
117In particular, deprecated modules should be listed here even if they are
118listed as an updated module in the L</Modules and Pragmata> section.
119
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120=head2 Use of qw(...) as parentheses
121
122Historically the parser fooled itself into thinking that C<qw(...)> literals
123were always enclosed in parentheses, and as a result you could sometimes omit
124parentheses around them:
125
126 for $x qw(a b c) { ... }
127
128The parser no longer lies to itself in this way. Wrap the list literal in
129parentheses, like:
130
131 for $x (qw(a b c)) { ... }
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132
133=head1 Performance Enhancements
134
135XXX Changes which enhance performance without changing behaviour go here. There
136may well be none in a stable release.
137
138[ List each enhancement as a =item entry ]
139
140=over 4
141
142=item *
143
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144Scalars containing regular expressions now only allocate the part of the C<SV>
145body they actually use, saving some space.
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146
147=back
148
149=head1 Modules and Pragmata
150
151XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
152go here. If Module::CoreList is updated, generate an initial draft of the
153following sections using F<Porting/corelist-perldelta.pl>, which prints stub
154entries to STDOUT. Results can be pasted in place of the '=head2' entries
155below. A paragraph summary for important changes should then be added by hand.
156In an ideal world, dual-life modules would have a F<Changes> file that could be
157cribbed.
158
159[ Within each section, list entries as a =item entry ]
160
161=head2 New Modules and Pragmata
162
163=over 4
164
165=item *
166
4997ece7 167XXX
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168
169=back
170
171=head2 Updated Modules and Pragmata
172
173=over 4
174
175=item *
176
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177C<blib> has been upgraded from version 1.05 to 1.06.
178
179=item *
180
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181C<bignum>, C<bigint>, and C<bigrat> have been upgraded from version 0.23 to
1820.24.
183
184=item *
185
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186C<warnings> has been upgraded from version 1.10 to 1.11.
187
188C<warnings::register> has been upgraded from version 1.01 to 1.02.
189
190It is now possible to register warning categories other than the names of
191packages using warnings::register. See L<perllexwarn> for more information.
192
193=item *
194
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195C<B::Debug> has been upgraded from version 1.12 to 1.14.
196
197=item *
198
b80fbfc1 199C<Data::Dumper> has been upgraded from version 2.126 to 2.128.
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200
201This fixes a crash when using custom sort functions that might cause the stack
202to change.
203
204=item *
205
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206C<Errno> has been upgraded from version 1.12 to 1.13.
207
208On some platforms with unusual header files, like Win32/gcc using mingw64
209headers, some constants which weren't actually error numbers have been exposed
210by C<Errno>. This has been fixed (RT#77416).
211
212=item *
213
37f6eaa4 214C<ExtUtils::MakeMaker> has been upgraded from version 6.56 to 6.57_05.
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215
216=item *
217
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218C<Filter::Simple> has been upgraded from version 0.84 to 0.85.
219
220=item *
221
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222C<Math::BigInt> has been upgraded from version 1.89_01 to 1.95.
223C<Math::BigInt::Calc> has been upgraded from version 0.52 to 0.54.
48c1efd2 224
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225This fixes, among other things, incorrect results when computing binomial
226coefficients (RT#77640).
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227
228=item *
229
68223daa 230C<Math::BigInt::FastCalc> has been upgraded from version 0.19 to 0.22.
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231
232=item *
233
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234C<Module::CoreList> has been upgraded from version 2.37 to 2.38.
235
236=item *
237
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238C<POSIX> has been upgraded from version 1.19 to 1.20.
239
240It now includes constants for POSIX signal constants.
241
242=item *
243
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244C<Tie::Hash> has been upgraded from version 1.03 to 1.04.
245
48c1efd2 246Calling C<< Tie::Hash->TIEHASH() >> used to loop forever. Now it C<croak>s.
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247
248=item *
249
ccb45ef4 250C<Unicode::Collate> has been upgraded from version 0.56 to 0.59.
4c793fe3 251
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252=item *
253
254C<XSLoader> has been upgraded from version 0.10 to 0.11.
255
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256=back
257
258=head2 Removed Modules and Pragmata
259
260=over 4
261
262=item *
263
264XXX
265
266=back
267
268=head1 Documentation
269
270XXX Changes to files in F<pod/> go here. Consider grouping entries by
271file and be sure to link to the appropriate page, e.g. L<perlfunc>.
272
273=head2 New Documentation
274
275XXX Changes which create B<new> files in F<pod/> go here.
276
277=head3 L<XXX>
278
279XXX Description of the purpose of the new file here
280
281=head2 Changes to Existing Documentation
282
283XXX Changes which significantly change existing files in F<pod/> go here.
284However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
285section.
286
0c692eed 287=head3 L<perlapi>
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288
289=over 4
290
291=item *
292
0c692eed 293Many of the optree construction functions are now documented.
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294
295=back
296
297=head1 Diagnostics
298
299The following additions or changes have been made to diagnostic output,
300including warnings and fatal error messages. For the complete list of
301diagnostic messages, see L<perldiag>.
302
303XXX New or changed warnings emitted by the core's C<C> code go here. Also
304include any changes in L<perldiag> that reconcile it to the C<C> code.
305
306[ Within each section, list entries as a =item entry ]
307
308=head2 New Diagnostics
309
310XXX Newly added diagnostic messages go here
311
312=over 4
313
314=item *
315
85318b69 316Use of qw(...) as parentheses is deprecated
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317
318=back
319
320=head2 Changes to Existing Diagnostics
321
322XXX Changes (i.e. rewording) of diagnostic messages go here
323
324=over 4
325
326=item *
327
328XXX
329
330=back
331
332=head1 Utility Changes
333
334XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go
335here. Most of these are built within the directories F<utils> and F<x2p>.
336
337[ List utility changes as a =head3 entry for each utility and =item
338entries for each change
339Use L<XXX> with program names to get proper documentation linking. ]
340
48c1efd2 341=head3 L<h2ph>
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342
343=over 4
344
345=item *
346
48c1efd2 347The use of a deprecated C<goto> construct has been removed (RT#74404).
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348
349=back
350
351=head1 Configuration and Compilation
352
353XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
354go here. Any other changes to the Perl build process should be listed here.
355However, any platform-specific changes should be listed in the
356L</Platform Support> section, instead.
357
358[ List changes as a =item entry ].
359
360=over 4
361
362=item *
363
364XXX
365
366=back
367
368=head1 Testing
369
370XXX Any significant changes to the testing of a freshly built perl should be
371listed here. Changes which create B<new> files in F<t/> go here as do any
372large changes to the testing harness (e.g. when parallel testing was added).
373Changes to existing files in F<t/> aren't worth summarising, although the bugs
374that they represent may be covered elsewhere.
375
376[ List each test improvement as a =item entry ]
377
378=over 4
379
380=item *
381
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382A rare race condition in F<t/op/while_readdir.t> has been fixed, stopping it
383from failing randomly when running tests in parallel.
4c793fe3 384
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385=item *
386
387The new F<t/op/leaky-magic.t> script tests that magic applied to variables in
388the main packages does not affect other packages.
389
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390=back
391
392=head1 Platform Support
393
394XXX Any changes to platform support should be listed in the sections below.
395
396[ Within the sections, list each platform as a =item entry with specific
397changes as paragraphs below it. ]
398
399=head2 New Platforms
400
401XXX List any platforms that this version of perl compiles on, that previous
402versions did not. These will either be enabled by new files in the F<hints/>
403directories, or new subdirectories and F<README> files at the top level of the
404source tree.
405
406=over 4
407
408=item XXX-some-platform
409
410XXX
411
412=back
413
414=head2 Discontinued Platforms
415
416XXX List any platforms that this version of perl no longer compiles on.
417
418=over 4
419
420=item XXX-some-platform
421
422XXX
423
424=back
425
426=head2 Platform-Specific Notes
427
428XXX List any changes for specific platforms. This could include configuration
429and compilation changes or changes in portability/compatibility. However,
430changes within modules for platforms should generally be listed in the
431L</Modules and Pragmata> section.
432
433=over 4
434
0c692eed 435=item VMS
4c793fe3 436
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437=over 4
438
439=item *
440
441Make PerlIOUnix_open honor default permissions on VMS.
442
443When perlio became the default and unixio became the default bottom layer, the
444most common path for creating files from Perl became C<PerlIOUnix_open>, which
445has always explicitly used C<0666> as the permission mask.
446
447To avoid this, C<0777> is now passed as the permissions to C<open()>. In the VMS
448CRTL, C<0777> has a special meaning over and above intersecting with the current
449umask; specifically, it allows Unix syscalls to preserve native default
450permissions.
451
452=back
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453
454=back
455
456=head1 Internal Changes
457
458XXX Changes which affect the interface available to C<XS> code go here.
459Other significant internal changes for future core maintainers should
460be noted as well.
461
462[ List each test improvement as a =item entry ]
463
464=over 4
465
466=item *
467
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468C<CALL_FPTR> and C<CPERLscope> have been removed deprecated.
469
470Those are left from an old implementation of C<MULTIPLICITY> using C++ objects,
471which has been removed in 5.8. Nowadays these macros do exactly nothing, so they
472shouldn't be used anymore.
473
474For compatibility, they are still defined for external C<XS> code. Only
475extensions defining C<PERL_CORE> must be updated now.
476
477=item *
478
479C<lex_stuff_pvs()> has been added as a convenience macro wrapping
480C<lex_stuff_pvn()> for literal strings.
481
482=item *
483
484The recursive part of the peephole optimizer is how hookable.
485
486In addition to C<PL_peepp>, for hooking into the toplevel peephole optimizer, a
487C<PL_rpeepp> is now available to hook into the optimizer recursing into
488side-chains of the optree.
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489
490=back
491
492=head1 Selected Bug Fixes
493
494XXX Important bug fixes in the core language are summarised here.
495Bug fixes in files in F<ext/> and F<lib/> are best summarised in
496L</Modules and Pragmata>.
497
498[ List each fix as a =item entry ]
499
500=over 4
501
502=item *
503
f4beb78f 504A regression introduced in perl 5.12.0, making
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505C<< my $x = 3; $x = length(undef) >> result in C<$x> set to C<3> has been
506fixed. C<$x> will now be C<undef>.
507
508=item *
509
510A fatal error in regular expressions when processing UTF-8 data has been fixed
511(RT#75680).
512
513=item *
514
515An erroneous regular expression engine optimization, that caused regex verbs
516like C<*COMMIT> to sometimes be ignored, has been removed.
517
518=item *
519
520The perl debugger now also works in taint mode (RT#76872).
4c793fe3 521
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522=item *
523
524Several memory leaks in cloning and freeing threaded perl interpreters have been
525fixed (RT#77352).
526
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527=item *
528
529A possible string corruption when doing regular expression matches on overloaded
530objects has been fixed (RT#77084).
531
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532=item *
533
534Magic applied to variables in the main package no longer affects other
535packages. See L</Magic Variables Outside the Main Package>, above [perl #76138].
536
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537=item *
538
539Opening a glob reference via C<< open $fh, ">", \*glob >> will no longer cause
540the glob to be corrupted when the file handle is printed to. This would cause
541perl to crash whenever the glob's contents were accessed [perl #77492].
542
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543=item *
544
d827d4bf 545The postincrement and postdecrement operators, C<++> and C<--> used to cause
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546leaks when being used on references. This has now been fixed.
547
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548=item *
549
550A bug when replacing the glob of a loop variable within the loop has been
551fixed [perl #21469]. This means the following code will no longer crash:
552
553 for $x (...) {
554 *x = *y;
555 }
556
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557=item *
558
559Perl would segfault if the undocumented C<Internals> functions that
560used reference prototypes were called with the C<&foo()> syntax,
561e.g. C<&Internals::SvREADONLY(undef)> [perl #77776].
562
563These functions now call C<SvROK> on their arguments before
564dereferencing them with C<SvRV>, and we test for this case in
565F<t/lib/universal.t>.
566
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567=back
568
569=head1 Known Problems
570
571XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
572tests that had to be C<TODO>ed for the release would be noted here, unless
573they were specific to a particular platform (see below).
574
575This is a list of some significant unfixed bugs, which are regressions
576from either 5.XXX.XXX or 5.XXX.XXX.
577
578[ List each fix as a =item entry ]
579
580=over 4
581
582=item *
583
584XXX
585
586=back
587
588=head1 Obituary
589
590XXX If any significant core contributor has died, we've added a short obituary
591here.
592
593=head1 Acknowledgements
594
595XXX The list of people to thank goes here.
596
597=head1 Reporting Bugs
598
599If you find what you think is a bug, you might check the articles
600recently posted to the comp.lang.perl.misc newsgroup and the perl
601bug database at http://rt.perl.org/perlbug/ . There may also be
602information at http://www.perl.org/ , the Perl Home Page.
603
604If you believe you have an unreported bug, please run the B<perlbug>
605program included with your release. Be sure to trim your bug down
606to a tiny but sufficient test case. Your bug report, along with the
607output of C<perl -V>, will be sent off to perlbug@perl.org to be
608analysed by the Perl porting team.
609
610If the bug you are reporting has security implications, which make it
611inappropriate to send to a publicly archived mailing list, then please send
612it to perl5-security-report@perl.org. This points to a closed subscription
613unarchived mailing list, which includes all the core committers, who be able
614to help assess the impact of issues, figure out a resolution, and help
615co-ordinate the release of patches to mitigate or fix the problem across all
616platforms on which Perl is supported. Please only use this address for
617security issues in the Perl core, not for modules independently
618distributed on CPAN.
619
620=head1 SEE ALSO
621
622The F<Changes> file for an explanation of how to view exhaustive details
623on what changed.
624
625The F<INSTALL> file for how to build Perl.
626
627The F<README> file for general stuff.
628
629The F<Artistic> and F<Copying> files for copyright information.
630
631=cut