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1=encoding utf8
2
8ebb9810 3=for release_engineer
85318b69 4* changelogged up to 95544aa
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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
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167L<warnings> and L<warnings::register> can now register categories other than
168the names of packages using warnings::register. See L<perllexwarn> for more
169information.
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170
171=back
172
173=head2 Updated Modules and Pragmata
174
175=over 4
176
177=item *
178
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179C<blib> has been upgraded from version 1.05 to 1.06.
180
181=item *
182
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183C<bignum>, C<bigint>, and C<bigrat> have been upgraded from version 0.23 to
1840.24.
185
186=item *
187
b80fbfc1 188C<Data::Dumper> has been upgraded from version 2.126 to 2.128.
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189
190This fixes a crash when using custom sort functions that might cause the stack
191to change.
192
193=item *
194
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195C<Errno> has been upgraded from version 1.12 to 1.13.
196
197On some platforms with unusual header files, like Win32/gcc using mingw64
198headers, some constants which weren't actually error numbers have been exposed
199by C<Errno>. This has been fixed (RT#77416).
200
201=item *
202
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203C<ExtUtils::MakeMaker> has been upgraded from version 6.56 to 6.57_01.
204
205=item *
206
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207C<Filter::Simple> has been upgraded from version 0.84 to 0.85.
208
209=item *
210
85318b69 211C<Math::BigInt> has been upgraded from version 1.89_01 to 1.92.
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212C<Math::BigInt::Calc> has been upgraded from version 0.52 to 0.53.
213
214This fixes incorrect results when computing binomial coefficients (RT#77640).
215
216=item *
217
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218C<Math::BigInt::FastCalc> has been upgraded from version 0.19 to 0.21.
219
220=item *
221
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222C<Module::CoreList> has been upgraded from version 2.37 to 2.38.
223
224=item *
225
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226C<Tie::Hash> has been upgraded from version 1.03 to 1.04.
227
48c1efd2 228Calling C<< Tie::Hash->TIEHASH() >> used to loop forever. Now it C<croak>s.
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229
230=item *
231
ccb45ef4 232C<Unicode::Collate> has been upgraded from version 0.56 to 0.59.
4c793fe3 233
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234=item *
235
236C<XSLoader> has been upgraded from version 0.10 to 0.11.
237
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238=back
239
240=head2 Removed Modules and Pragmata
241
242=over 4
243
244=item *
245
246XXX
247
248=back
249
250=head1 Documentation
251
252XXX Changes to files in F<pod/> go here. Consider grouping entries by
253file and be sure to link to the appropriate page, e.g. L<perlfunc>.
254
255=head2 New Documentation
256
257XXX Changes which create B<new> files in F<pod/> go here.
258
259=head3 L<XXX>
260
261XXX Description of the purpose of the new file here
262
263=head2 Changes to Existing Documentation
264
265XXX Changes which significantly change existing files in F<pod/> go here.
266However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
267section.
268
0c692eed 269=head3 L<perlapi>
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270
271=over 4
272
273=item *
274
0c692eed 275Many of the optree construction functions are now documented.
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276
277=back
278
279=head1 Diagnostics
280
281The following additions or changes have been made to diagnostic output,
282including warnings and fatal error messages. For the complete list of
283diagnostic messages, see L<perldiag>.
284
285XXX New or changed warnings emitted by the core's C<C> code go here. Also
286include any changes in L<perldiag> that reconcile it to the C<C> code.
287
288[ Within each section, list entries as a =item entry ]
289
290=head2 New Diagnostics
291
292XXX Newly added diagnostic messages go here
293
294=over 4
295
296=item *
297
85318b69 298Use of qw(...) as parentheses is deprecated
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299
300=back
301
302=head2 Changes to Existing Diagnostics
303
304XXX Changes (i.e. rewording) of diagnostic messages go here
305
306=over 4
307
308=item *
309
310XXX
311
312=back
313
314=head1 Utility Changes
315
316XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go
317here. Most of these are built within the directories F<utils> and F<x2p>.
318
319[ List utility changes as a =head3 entry for each utility and =item
320entries for each change
321Use L<XXX> with program names to get proper documentation linking. ]
322
48c1efd2 323=head3 L<h2ph>
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324
325=over 4
326
327=item *
328
48c1efd2 329The use of a deprecated C<goto> construct has been removed (RT#74404).
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330
331=back
332
333=head1 Configuration and Compilation
334
335XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
336go here. Any other changes to the Perl build process should be listed here.
337However, any platform-specific changes should be listed in the
338L</Platform Support> section, instead.
339
340[ List changes as a =item entry ].
341
342=over 4
343
344=item *
345
346XXX
347
348=back
349
350=head1 Testing
351
352XXX Any significant changes to the testing of a freshly built perl should be
353listed here. Changes which create B<new> files in F<t/> go here as do any
354large changes to the testing harness (e.g. when parallel testing was added).
355Changes to existing files in F<t/> aren't worth summarising, although the bugs
356that they represent may be covered elsewhere.
357
358[ List each test improvement as a =item entry ]
359
360=over 4
361
362=item *
363
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364A rare race condition in F<t/op/while_readdir.t> has been fixed, stopping it
365from failing randomly when running tests in parallel.
4c793fe3 366
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367=item *
368
369The new F<t/op/leaky-magic.t> script tests that magic applied to variables in
370the main packages does not affect other packages.
371
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372=back
373
374=head1 Platform Support
375
376XXX Any changes to platform support should be listed in the sections below.
377
378[ Within the sections, list each platform as a =item entry with specific
379changes as paragraphs below it. ]
380
381=head2 New Platforms
382
383XXX List any platforms that this version of perl compiles on, that previous
384versions did not. These will either be enabled by new files in the F<hints/>
385directories, or new subdirectories and F<README> files at the top level of the
386source tree.
387
388=over 4
389
390=item XXX-some-platform
391
392XXX
393
394=back
395
396=head2 Discontinued Platforms
397
398XXX List any platforms that this version of perl no longer compiles on.
399
400=over 4
401
402=item XXX-some-platform
403
404XXX
405
406=back
407
408=head2 Platform-Specific Notes
409
410XXX List any changes for specific platforms. This could include configuration
411and compilation changes or changes in portability/compatibility. However,
412changes within modules for platforms should generally be listed in the
413L</Modules and Pragmata> section.
414
415=over 4
416
0c692eed 417=item VMS
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419=over 4
420
421=item *
422
423Make PerlIOUnix_open honor default permissions on VMS.
424
425When perlio became the default and unixio became the default bottom layer, the
426most common path for creating files from Perl became C<PerlIOUnix_open>, which
427has always explicitly used C<0666> as the permission mask.
428
429To avoid this, C<0777> is now passed as the permissions to C<open()>. In the VMS
430CRTL, C<0777> has a special meaning over and above intersecting with the current
431umask; specifically, it allows Unix syscalls to preserve native default
432permissions.
433
434=back
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435
436=back
437
438=head1 Internal Changes
439
440XXX Changes which affect the interface available to C<XS> code go here.
441Other significant internal changes for future core maintainers should
442be noted as well.
443
444[ List each test improvement as a =item entry ]
445
446=over 4
447
448=item *
449
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450C<CALL_FPTR> and C<CPERLscope> have been removed deprecated.
451
452Those are left from an old implementation of C<MULTIPLICITY> using C++ objects,
453which has been removed in 5.8. Nowadays these macros do exactly nothing, so they
454shouldn't be used anymore.
455
456For compatibility, they are still defined for external C<XS> code. Only
457extensions defining C<PERL_CORE> must be updated now.
458
459=item *
460
461C<lex_stuff_pvs()> has been added as a convenience macro wrapping
462C<lex_stuff_pvn()> for literal strings.
463
464=item *
465
466The recursive part of the peephole optimizer is how hookable.
467
468In addition to C<PL_peepp>, for hooking into the toplevel peephole optimizer, a
469C<PL_rpeepp> is now available to hook into the optimizer recursing into
470side-chains of the optree.
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471
472=back
473
474=head1 Selected Bug Fixes
475
476XXX Important bug fixes in the core language are summarised here.
477Bug fixes in files in F<ext/> and F<lib/> are best summarised in
478L</Modules and Pragmata>.
479
480[ List each fix as a =item entry ]
481
482=over 4
483
484=item *
485
f4beb78f 486A regression introduced in perl 5.12.0, making
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487C<< my $x = 3; $x = length(undef) >> result in C<$x> set to C<3> has been
488fixed. C<$x> will now be C<undef>.
489
490=item *
491
492A fatal error in regular expressions when processing UTF-8 data has been fixed
493(RT#75680).
494
495=item *
496
497An erroneous regular expression engine optimization, that caused regex verbs
498like C<*COMMIT> to sometimes be ignored, has been removed.
499
500=item *
501
502The perl debugger now also works in taint mode (RT#76872).
4c793fe3 503
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504=item *
505
506Several memory leaks in cloning and freeing threaded perl interpreters have been
507fixed (RT#77352).
508
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509=item *
510
511A possible string corruption when doing regular expression matches on overloaded
512objects has been fixed (RT#77084).
513
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514=item *
515
516Magic applied to variables in the main package no longer affects other
517packages. See L</Magic Variables Outside the Main Package>, above [perl #76138].
518
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519=item *
520
521Opening a glob reference via C<< open $fh, ">", \*glob >> will no longer cause
522the glob to be corrupted when the file handle is printed to. This would cause
523perl to crash whenever the glob's contents were accessed [perl #77492].
524
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525=item *
526
d827d4bf 527The postincrement and postdecrement operators, C<++> and C<--> used to cause
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528leaks when being used on references. This has now been fixed.
529
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530=item *
531
532A bug when replacing the glob of a loop variable within the loop has been
533fixed [perl #21469]. This means the following code will no longer crash:
534
535 for $x (...) {
536 *x = *y;
537 }
538
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539=back
540
541=head1 Known Problems
542
543XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
544tests that had to be C<TODO>ed for the release would be noted here, unless
545they were specific to a particular platform (see below).
546
547This is a list of some significant unfixed bugs, which are regressions
548from either 5.XXX.XXX or 5.XXX.XXX.
549
550[ List each fix as a =item entry ]
551
552=over 4
553
554=item *
555
556XXX
557
558=back
559
560=head1 Obituary
561
562XXX If any significant core contributor has died, we've added a short obituary
563here.
564
565=head1 Acknowledgements
566
567XXX The list of people to thank goes here.
568
569=head1 Reporting Bugs
570
571If you find what you think is a bug, you might check the articles
572recently posted to the comp.lang.perl.misc newsgroup and the perl
573bug database at http://rt.perl.org/perlbug/ . There may also be
574information at http://www.perl.org/ , the Perl Home Page.
575
576If you believe you have an unreported bug, please run the B<perlbug>
577program included with your release. Be sure to trim your bug down
578to a tiny but sufficient test case. Your bug report, along with the
579output of C<perl -V>, will be sent off to perlbug@perl.org to be
580analysed by the Perl porting team.
581
582If the bug you are reporting has security implications, which make it
583inappropriate to send to a publicly archived mailing list, then please send
584it to perl5-security-report@perl.org. This points to a closed subscription
585unarchived mailing list, which includes all the core committers, who be able
586to help assess the impact of issues, figure out a resolution, and help
587co-ordinate the release of patches to mitigate or fix the problem across all
588platforms on which Perl is supported. Please only use this address for
589security issues in the Perl core, not for modules independently
590distributed on CPAN.
591
592=head1 SEE ALSO
593
594The F<Changes> file for an explanation of how to view exhaustive details
595on what changed.
596
597The F<INSTALL> file for how to build Perl.
598
599The F<README> file for general stuff.
600
601The F<Artistic> and F<Copying> files for copyright information.
602
603=cut