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perldelta for 254707b
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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 v5.25.9
eabfc7bc 9
2cfe9b50 10=head1 DESCRIPTION
eabfc7bc 11
3ce6a296 12This document describes differences between the 5.25.8 release and the 5.25.9
4b8803f0 13release.
f3ed8cbf 14
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15If you are upgrading from an earlier release such as 5.25.7, first read
16L<perl5258delta>, which describes differences between 5.25.7 and 5.25.8.
17
18=head1 Notice
19
20XXX Any important notices here
8bbdbfcb 21
733dba2b 22=head1 Core Enhancements
ce6646d7 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.
27
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28=head2 New regular expression modifier C</xx>
29
30Specifying two C<x> characters to modify a regular expression pattern
31does everything that a single one does, but additionally TAB and SPACE
32characters within a bracketed character class are generally ignored and
33can be added to improve readability, like
34S<C</[ ^ A-Z d-f p-x ]/xx>>. Details are at
35L<perlre/E<sol>x and E<sol>xx>.
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36
37=head1 Security
38
39XXX Any security-related notices go here. In particular, any security
40vulnerabilities closed should be noted here rather than in the
41L</Selected Bug Fixes> section.
42
43[ List each security issue as a =head2 entry ]
44
45=head1 Incompatible Changes
46
47XXX For a release on a stable branch, this section aspires to be:
48
49 There are no changes intentionally incompatible with 5.XXX.XXX
50 If any exist, they are bugs, and we request that you submit a
51 report. See L</Reporting Bugs> below.
52
53[ List each incompatible change as a =head2 entry ]
54
55=head1 Deprecations
56
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57=head2 String delimiters that aren't stand-alone graphemes are now
58deprecated
59
60In order for Perl to eventually allow string delimiters to be Unicode
61grapheme clusters (which look like a single character, but may be
62a sequence of several ones), we have to stop allowing a single char
63delimiter that isn't a grapheme by itself. These are unlikely to exist
64in actual code, as they would typically display as attached to the
65character in front of them.
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66
67=head2 Module removals
68
69XXX Remove this section if inapplicable.
70
71The following modules will be removed from the core distribution in a
72future release, and will at that time need to be installed from CPAN.
73Distributions on CPAN which require these modules will need to list them as
74prerequisites.
75
76The core versions of these modules will now issue C<"deprecated">-category
77warnings to alert you to this fact. To silence these deprecation warnings,
78install the modules in question from CPAN.
79
80Note that these are (with rare exceptions) fine modules that you are encouraged
81to continue to use. Their disinclusion from core primarily hinges on their
82necessity to bootstrapping a fully functional, CPAN-capable Perl installation,
83not usually on concerns over their design.
eaed4a85 84
3ce6a296 85=over
eaed4a85 86
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87=item XXX
88
89XXX Note that deprecated modules should be listed here even if they are listed
90as an updated module in the L</Modules and Pragmata> section.
91
92=back
93
94[ List each other deprecation as a =head2 entry ]
eaed4a85 95
733dba2b 96=head1 Performance Enhancements
226eba01 97
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98XXX Changes which enhance performance without changing behaviour go here.
99There may well be none in a stable release.
8bbdbfcb 100
3ce6a296 101[ List each enhancement as a =item entry ]
8bbdbfcb 102
3ce6a296 103=over 4
8bbdbfcb 104
3ce6a296 105=item *
dd3d2a3f 106
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107A hash in boolean context is now sometimes faster, e.g.
108
109 if (!%h) { ... }
110
111This was already special-cased, but some cases were missed, and even the
112ones which weren't have been improved.
dd3d2a3f 113
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114=back
115
733dba2b 116=head1 Modules and Pragmata
8bbdbfcb 117
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118XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
119go here. If Module::CoreList is updated, generate an initial draft of the
120following sections using F<Porting/corelist-perldelta.pl>. A paragraph summary
121for important changes should then be added by hand. In an ideal world,
122dual-life modules would have a F<Changes> file that could be cribbed.
123
124[ Within each section, list entries as a =item entry ]
125
126=head2 New Modules and Pragmata
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127
128=over 4
129
130=item *
131
3ce6a296 132XXX
8bbdbfcb 133
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134=back
135
136=head2 Updated Modules and Pragmata
ff10d69b 137
3ce6a296 138=over 4
ff10d69b 139
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140=item *
141
3ce6a296 142L<XXX> has been upgraded from version A.xx to B.yy.
8bbdbfcb 143
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144=item *
145
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146L<re> has been upgraded from version 0.33 to 0.34;
147
148This adds support for the new L<C</xx>|perlre/E<sol>x and E<sol>xx>
149regular expression pattern modifier, and a change to the L<S<C<use re
150'strict'>>|re/'strict' mode> experimental feature. When S<C<re
151'strict'>> is enabled, a warning now will be generated for all
152unescaped uses of the two characters C<}> and C<]> in regular
153expression patterns (outside bracketed character classes) that are taken
154literally. This brings them more in line with the C<)> character which
155is always a metacharacter unless escaped. Being a metacharacter only
156sometimes, depending on action at a distance, can lead to silently
157having the pattern mean something quite different than was intended,
158which the S<C<re 'strict'>> mode is intended to minimize.
159
160=item *
161
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162L<B::Xref> has been upgraded from version 1.05 to 1.06.
163
164=item *
165
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166L<Compress::Raw::Bzip2> has been upgraded from version 2.069 to 2.070.
167
168=item *
169
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170L<Compress::Raw::Zlib> has been upgraded from version 2.069 to 2.070.
171
172=item *
173
1146f1f7 174L<DB_File> has been upgraded from version 1.838 to 1.840.
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175
176=item *
177
1146f1f7 178L<Devel::SelfStubber> has been upgraded from version 1.05 to 1.06.
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179
180=item *
181
1146f1f7 182L<diagnostics> has been upgraded from version 1.35 to 1.36.
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183
184=item *
185
186L<DynaLoader> has been upgraded from version 1.40 to 1.41.
187
188=item *
189
190L<Errno> has been upgraded from version 1.27 to 1.28.
191
192=item *
193
194L<ExtUtils::Embed> has been upgraded from version 1.33 to 1.34.
195
196=item *
197
198L<I18N::LangTags> has been upgraded from version 0.41 to 0.42.
199
200=item *
201
202L<lib> has been upgraded from version 0.63 to 0.64.
203
204=item *
205
59aeb939 206L<Module::CoreList> has been upgraded from version 5.20161220 to 5.20170120.
d4151a23 207
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208=item *
209
4ee2b8db 210L<OS2::Process> has been upgraded from version 1.11 to 1.12.
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211
212=item *
213
214L<perl5db.pl> has been upgraded from version 1.50 to 1.51.
215
216=item *
217
74ef8fd9 218L<Storable> has been upgraded from version 2.59 to 2.61.
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219
220=item *
221
222L<Symbol> has been upgraded from version 1.07 to 1.08.
223
224=item *
225
226L<Term::ReadLine> has been upgraded from version 1.15 to 1.16.
227
228=item *
229
230L<Test> has been upgraded from version 1.29 to 1.30.
231
232=item *
233
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234L<threads::shared> has been upgraded from version 1.52 to 1.53.
235
236=item *
237
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238L<Unicode::UCD> has been upgraded from version 0.67 to 0.68.
239
240=item *
241
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242L<VMS::DCLsym> has been upgraded from version 1.07 to 1.08.
243
244=item *
245
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246L<XSLoader> has been upgraded from version 0.24 to 0.26.
247
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248=item *
249
250L<CPAN> has been upgraded from version 2.14_01 to 2.16.
251
3ce6a296 252=back
8bbdbfcb 253
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254=head2 Removed Modules and Pragmata
255
256=over 4
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257
258=item *
259
3ce6a296 260XXX
8bbdbfcb 261
3ce6a296 262=back
8bbdbfcb 263
3ce6a296 264=head1 Documentation
8bbdbfcb 265
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266XXX Changes to files in F<pod/> go here. Consider grouping entries by
267file and be sure to link to the appropriate page, e.g. L<perlfunc>.
8bbdbfcb 268
3ce6a296 269=head2 New Documentation
8bbdbfcb 270
3ce6a296 271XXX Changes which create B<new> files in F<pod/> go here.
8bbdbfcb 272
3ce6a296 273=head3 L<XXX>
8bbdbfcb 274
3ce6a296 275XXX Description of the purpose of the new file here
8bbdbfcb 276
3ce6a296 277=head2 Changes to Existing Documentation
8bbdbfcb 278
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279XXX Changes which significantly change existing files in F<pod/> go here.
280However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
281section.
282
283=head3 L<XXX>
8bbdbfcb 284
3ce6a296 285=over 4
8bbdbfcb 286
107db227 287=item *
8bbdbfcb 288
3ce6a296 289XXX Description of the change here
8bbdbfcb 290
3ce6a296 291=back
8bbdbfcb 292
3ce6a296 293=head1 Diagnostics
8bbdbfcb 294
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295The following additions or changes have been made to diagnostic output,
296including warnings and fatal error messages. For the complete list of
297diagnostic messages, see L<perldiag>.
298
299XXX New or changed warnings emitted by the core's C<C> code go here. Also
300include any changes in L<perldiag> that reconcile it to the C<C> code.
8c3f6b0b 301
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302=head2 New Diagnostics
303
304XXX Newly added diagnostic messages go under here, separated into New Errors
305and New Warnings
306
307=head3 New Errors
308
309=over 4
a09f502b 310
107db227 311=item *
2c4879e2 312
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313XXX L<message|perldiag/"message">
314
315=back
316
317=head3 New Warnings
318
319=over 4
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320
321=item *
322
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323XXX L<message|perldiag/"message">
324
325=back
326
327=head2 Changes to Existing Diagnostics
328
57b3a6b6 329As of Perl 5.25.9, all new deprecations will come with a version in
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330which the feature will disappear. And with a few exceptions, most
331existing deprecations will state when they'll disappear. As such, most
332deprecation messages have changed.
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333
334=over 4
bd5630ab 335
107db227 336=item *
2c4879e2 337
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338Attribute "locked" is deprecated, and will disappear in Perl 5.28
339
340=item *
341
342Attribute "unique" is deprecated, and will disappear in Perl 5.28
343
344=item *
345
346"\c%c" is more clearly written simply as "%s". This will be a fatal error
347in Perl 5.28
348
349=item *
350
351Constants from lexical variables potentially modified elsewhere are
352deprecated. This will not be allowed in Perl 5.32
353
354=item *
355
356Deprecated use of my() in false conditional. This will be a fatal error
357in Perl 5.30
358
359=item *
360
361dump() better written as CORE::dump(). dump() will no longer be available
362in Perl 5.30
363
364=item *
365
366${^ENCODING} is no longer supported. Its use will be fatal in Perl 5.28
367
368=item *
369
370File::Glob::glob() will disappear in perl 5.30. Use File::Glob::bsd_glob()
371instead.
372
373=item *
374
375%s() is deprecated on :utf8 handles. This will be a fatal error in Perl 5.30
376
377=item *
378
379$* is no longer supported. Its use will be fatal in Perl 5.30
380
381=item *
382
383$* is no longer supported. Its use will be fatal in Perl 5.30
384
385=item *
386
387Opening dirhandle %s also as a file. This will be a fatal error in Perl 5.28
388
389=item *
390
391Opening filehandle %s also as a directory. This will be a fatal
392error in Perl 5.28
393
394=item *
395
396Setting $/ to a reference to %s as a form of slurp is deprecated,
397treating as undef. This will be fatal in Perl 5.28
398
399=item *
400
401Unescaped left brace in regex is deprecated here (and will be fatal
402in Perl 5.30), passed through in regex; marked by S<<-- HERE> in m/%s/
403
404=item *
405
406Unknown charname '' is deprecated. Its use will be fatal in Perl 5.28
407
408=item *
409
410Use of bare << to mean <<"" is deprecated. Its use will be fatal in Perl 5.28
411
412=item *
413
414Use of code point 0x%s is deprecated; the permissible max is 0x%s.
415This will be fatal in Perl 5.28
416
417=item *
418
419Use of comma-less variable list is deprecated. Its use will be fatal
420in Perl 5.28
421
422=item *
423
424Use of inherited AUTOLOAD for non-method %s() is deprecated. This
425will be fatal in Perl 5.28
426
427=item *
428
429Use of strings with code points over 0xFF as arguments to %s operator
430is deprecated. This will be a fatal error in Perl 5.28
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431
432=back
433
434=head1 Utility Changes
435
436XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go here.
437Most of these are built within the directory F<utils>.
438
439[ List utility changes as a =head2 entry for each utility and =item
440entries for each change
441Use L<XXX> with program names to get proper documentation linking. ]
442
443=head2 L<XXX>
444
445=over 4
a09f502b 446
107db227 447=item *
8bbdbfcb 448
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449XXX
450
451=back
452
453=head1 Configuration and Compilation
454
455XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
456go here. Any other changes to the Perl build process should be listed here.
457However, any platform-specific changes should be listed in the
458L</Platform Support> section, instead.
459
460[ List changes as a =item entry ].
461
462=over 4
8bbdbfcb 463
107db227 464=item *
8bbdbfcb 465
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466The C<dtrace> build process has further changes:
467
468=over
469
470=item *
471
472If the C<-xnolibs> is available, use that so a F<dtrace> perl can be
473built within a FreeBSD jail.
474
475=item *
476
477On systems that build a dtrace object file (FreeBSD, Solaris and
478SystemTap's dtrace emulation), copy the input objects to a separate
479directory and process them there, and use those objects in the link,
480since C<dtrace -G> also modifies these objects.
481
482=item *
483
484Add libelf to the build on FreeBSD 10.x, since dtrace adds references
485to libelf symbols.
486
487=item *
488
489Generate a dummy dtrace_main.o if C<dtrace -G> fails to build it. A
490default build on Solaris generates probes from the unused inline
491functions, while they don't on FreeBSD, which causes C<dtrace -G> to
492fail.
493
494=back
495
496[perl #130108]
3ce6a296 497
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498=item *
499
500You can now disable perl's use of the PERL_HASH_SEED and
501PERL_PERTURB_KEYS environment variables by configureing perl with
502C<-Accflags=NO_PERL_HASH_ENV>.
503
504=item *
505
506You can now disable perl's use of the PERL_HASH_SEED_DEBUG environment
507variable by configuring perl with
508C<-Accflags=-DNO_PERL_HASH_SEED_DEBUG>.
509
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510=back
511
512=head1 Testing
513
514XXX Any significant changes to the testing of a freshly built perl should be
515listed here. Changes which create B<new> files in F<t/> go here as do any
516large changes to the testing harness (e.g. when parallel testing was added).
517Changes to existing files in F<t/> aren't worth summarizing, although the bugs
518that they represent may be covered elsewhere.
519
520[ List each test improvement as a =item entry ]
521
522=over 4
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523
524=item *
525
3ce6a296 526XXX
07cfdfcc 527
262514fd 528=back
2c4879e2 529
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530=head1 Platform Support
531
532XXX Any changes to platform support should be listed in the sections below.
533
534[ Within the sections, list each platform as a =item entry with specific
535changes as paragraphs below it. ]
536
537=head2 New Platforms
538
539XXX List any platforms that this version of perl compiles on, that previous
540versions did not. These will either be enabled by new files in the F<hints/>
541directories, or new subdirectories and F<README> files at the top level of the
542source tree.
543
544=over 4
545
546=item XXX-some-platform
547
548XXX
549
550=back
551
552=head2 Discontinued Platforms
553
554XXX List any platforms that this version of perl no longer compiles on.
555
556=over 4
557
558=item XXX-some-platform
559
560XXX
561
562=back
563
564=head2 Platform-Specific Notes
565
566XXX List any changes for specific platforms. This could include configuration
567and compilation changes or changes in portability/compatibility. However,
568changes within modules for platforms should generally be listed in the
569L</Modules and Pragmata> section.
570
571=over 4
572
573=item XXX-some-platform
574
575XXX
576
577=back
578
579=head1 Internal Changes
580
581XXX Changes which affect the interface available to C<XS> code go here. Other
582significant internal changes for future core maintainers should be noted as
583well.
584
585[ List each change as a =item entry ]
a09f502b 586
733dba2b 587=over 4
a09f502b 588
a07f6112 589=item *
a09f502b 590
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591New versions of macros like C<isALPHA_utf8> and C<toLOWER_utf8> have
592been added, each with the
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593suffix C<_safe>, like C<isSPACE_utf8_safe>. These take an extra
594parameter, giving an upper limit of how far into the string it is safe
595to read. Using the old versions could cause attempts to read beyond the
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596end of the input buffer if the UTF-8 is not well-formed, and ther use
597now raises a deprecation warning. Details are at
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598L<perlapi/Character classification>.
599
600=item *
601
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602Calling macros like C<isALPHA_utf8> on malformed UTF-8 have issued a
603deprecation warning since Perl v5.18. They now die.
fa8ab374 604Similarly, macros like C<toLOWER_utf8> on malformed UTF-8 now die.
3ce6a296 605
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606=item *
607
608Calling the functions C<utf8n_to_uvchr> and its derivatives, while
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609passing a string length of 0 is now asserted against in DEBUGGING
610builds, and otherwise returns the Unicode REPLACEMENT CHARACTER. If
611you have nothing to decode, you shouldn't call the decode function.
d1f8d421 612
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613=item *
614
615The functions C<utf8n_to_uvchr> and its derivatives now return the
616Unicode REPLACEMENT CHARACTER if called with UTF-8 that has the overlong
617malformation, and that malformation is allowed by the input parameters.
618This malformation is where the UTF-8 looks valid syntactically, but
619there is a shorter sequence that yields the same code point. This has
620been forbidden since Unicode version 3.1.
621
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622=item *
623
624The functions C<utf8n_to_uvchr> and its derivatives now accept an input
625flag to allow the overflow malformation. This malformation is when the
626UTF-8 may be syntactically valid, but the code point it represents is
627not capable of being represented in the word length on the platform.
628What "allowed" means in this case is that the function doesn't return an
629error, and advances the parse pointer to beyond the UTF-8 in question,
630but it returns the Unicode REPLACEMENT CHARACTER as the value of the
631code point (since the real value is not representable).
632
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633=back
634
635=head1 Selected Bug Fixes
636
637XXX Important bug fixes in the core language are summarized here. Bug fixes in
638files in F<ext/> and F<lib/> are best summarized in L</Modules and Pragmata>.
639
640[ List each fix as a =item entry ]
641
642=over 4
a09f502b 643
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644=item *
645
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646Under C<use utf8>, the entire Perl program is now checked that the UTF-8
647is wellformed. This resolves [perl #126310].
3ce6a296 648
d6c970c7
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649=item *
650
651The range operator C<..> on strings now handles its arguments correctly when in
652the scope of the L<< C<unicode_strings>|feature/"The 'unicode_strings' feature" >>
653feature. The previous behaviour was sufficiently unexpected that we believe no
654correct program could have made use of it.
655
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656=item *
657
658The S<split> operator did not ensure enough space was allocated for
659its return value in scalar context. It could then write a single
660pointer immediately beyond the end of the memory block allocated for
661the stack. [perl #130262]
662
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663=item *
664
665Using a large code point with the C<W> pack template character with
666the current output position aligned at just the right point could
667cause a write a single zero byte immediately beyond the end of an
668allocated buffer. [perl #129149]
669
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670=back
671
672=head1 Known Problems
673
674XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
675tests that had to be C<TODO>ed for the release would be noted here. Unfixed
676platform specific bugs also go here.
36cabe94 677
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678[ List each fix as a =item entry ]
679
680=over 4
681
682=item *
683
684XXX
36cabe94 685
a07f6112 686=back
7d897bd0 687
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688=head1 Errata From Previous Releases
689
690=over 4
8bbdbfcb 691
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692=item *
693
694XXX Add anything here that we forgot to add, or were mistaken about, in
695the perldelta of a previous release.
8bbdbfcb 696
3ce6a296 697=back
262514fd 698
3ce6a296 699=head1 Obituary
a6a32e96 700
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701XXX If any significant core contributor has died, we've added a short obituary
702here.
262514fd 703
3ce6a296 704=head1 Acknowledgements
226eba01 705
3ce6a296 706XXX Generate this with:
24528e8e 707
3ce6a296 708 perl Porting/acknowledgements.pl v5.25.5..HEAD
f5b73711 709
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710=head1 Reporting Bugs
711
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712If you find what you think is a bug, you might check the perl bug database
713at L<https://rt.perl.org/> . There may also be information at
4b8803f0 714L<http://www.perl.org/> , the Perl Home Page.
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716If you believe you have an unreported bug, please run the L<perlbug> program
717included with your release. Be sure to trim your bug down to a tiny but
718sufficient test case. Your bug report, along with the output of C<perl -V>,
719will be sent off to perlbug@perl.org to be analysed by the Perl porting team.
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721If the bug you are reporting has security implications which make it
722inappropriate to send to a publicly archived mailing list, then see
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723L<perlsec/SECURITY VULNERABILITY CONTACT INFORMATION>
724for details of how to report the issue.
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725
726=head1 SEE ALSO
727
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728The F<Changes> file for an explanation of how to view exhaustive details on
729what changed.
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730
731The F<INSTALL> file for how to build Perl.
732
733The F<README> file for general stuff.
734
735The F<Artistic> and F<Copying> files for copyright information.
736
737=cut