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Increase stylistic consistency in perldelta by adding C<> and F<>.
[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
6XXX needs to be processed before release. ]
c71a852f 7
34dc2ec0 8perldelta - what is new for perl v5.15.0
6e925ecb 9
f5938650 10=for comment
da507230 11This has been completed up to 3ed94dc04.
f5938650 12
34dc2ec0 13=head1 DESCRIPTION
a27ff1be 14
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15This document describes differences between the 5.15.0 release and
16the 5.14.0 release.
a27ff1be 17
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18If you are upgrading from an earlier release such as 5.YYY.YYY, first read
19L<perl5YYYdelta>, which describes differences between 5.ZZZ.ZZZ and
205.YYY.YYY.
a27ff1be 21
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22Some of the changes have been included in Perl 5.14.1. These are
23indicated with a "(5.14.1)" marker.
24
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25XXX compare this perldelta to 5.14.1 and double check the notation
26
34dc2ec0 27=head1 Notice
a27ff1be 28
34dc2ec0 29XXX Any important notices here
a27ff1be 30
34dc2ec0 31=head1 Core Enhancements
a27ff1be 32
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33XXX New core language features go here. Summarise user-visible core language
34enhancements. Particularly prominent performance optimisations could go
35here, but most should go in the L</Performance Enhancements> section.
a27ff1be 36
34dc2ec0 37[ List each enhancement as a =head2 entry ]
a27ff1be 38
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39=head2 C<CORE::> works on all keywords
40
41The C<CORE::> prefix can now be used on keywords enabled by
42L<feature.pm|feature>, even outside the scope of C<use feature>.
43
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44=head2 C<continue> no longer requires the "switch" feature
45
46The C<continue> keyword has two meanings. It can introduce a C<continue>
47block after a loop, or it can exit the current C<when> block. Up till now,
48the latter meaning was only valid with the "switch" feature enabled, and
49was a syntax error otherwise. Since the main purpose of feature.pm is to
50avoid conflicts with user-defined subroutines, there is no reason for
51C<continue> to depend on it.
52
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53=head2 C<$$> can be assigned to
54
55C<$$> was made read-only in Perl 5.8.0. But only sometimes: C<local $$>
56would make it writable again. Some CPAN modules were using C<local $$> or
57XS code to bypass the read-only check, so there is no reason to keep C<$$>
58read-only. (This change also allowed a bug to be fixed while maintaining
59backward compatibility.)
60
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61=head2 Features inside the debugger
62
63The current Perl's feature bundle is now enabled for commands entered in
64the interactive debugger.
65
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66=head2 C<\N{...}> can now have Unicode loose name matching
67
68This is described in the C<charnames> item in
69L</Updated Modules and Pragmata> below.
70
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71=head2 Breakpoints with file names
72
73The debugger's "b" command for setting breakpoints now allows a line number
74to be prefixed with a file name. See
75L<perldebug/"b [file]:[line] [condition]">.
76
34dc2ec0 77=head1 Security
a27ff1be 78
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79XXX Any security-related notices go here. In particular, any security
80vulnerabilities closed should be noted here rather than in the
81L</Selected Bug Fixes> section.
a27ff1be 82
34dc2ec0 83[ List each security issue as a =head2 entry ]
a27ff1be 84
34dc2ec0 85=head1 Incompatible Changes
9a5a48b7 86
34dc2ec0 87[ List each incompatible change as a =head2 entry ]
9a5a48b7 88
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89=head2 Tying scalars that hold typeglobs
90
91Attempting to tie a scalar after a typeglob was assigned to it would
92instead tie the handle in the typeglob's IO slot. This meant that it was
93impossible to tie the scalar itself. Similar problems affected C<tied> and
94C<untie>: C<tied $scalar> would return false on a tied scalar if the last
95thing returned was a typeglob, and C<untie $scalar> on such a tied scalar
96would do nothing.
97
98We fixed this problem before Perl 5.14.0, but it caused problems with some
99CPAN modules, so we put in a deprecation cycle instead.
100
101Now the deprecation has been removed and this bug has been fixed. So
102C<tie $scalar> will always tie the scalar, not the handle it holds. To tie
103the handle, use C<tie *$scalar> (with an explicit asterisk). The same
104applies to C<tied *$scalar> and C<untie *$scalar>.
105
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106=head2 IPC::Open3 no longer provides C<xfork()>, C<xclose_on_exec()>
107and C<xpipe_anon()>
108
109All three functions were private, undocumented and unexported. They do
110not appear to be used by any code on CPAN. Two have been inlined and one
111deleted entirely.
112
113=head2 C<$$> no longer caches PID
114
115Previously, if one embeds Perl or uses XS and calls fork(3) from C, Perls
116notion of C<$$> could go out of sync with what getpid() returns. By always
117fetching the value of C<$$> via getpid(), this potential bug is eliminated.
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118Code that depends on the caching behavior will break. As described in
119L</Core Enhancements>, C<$$> is now writable, but it will be reset during a
120fork.
384e62c0 121
34dc2ec0 122=head1 Deprecations
cdc10f43 123
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124XXX Any deprecated features, syntax, modules etc. should be listed here.
125In particular, deprecated modules should be listed here even if they are
126listed as an updated module in the L</Modules and Pragmata> section.
cdc10f43 127
34dc2ec0 128[ List each deprecation as a =head2 entry ]
9a5a48b7 129
34dc2ec0 130=head1 Performance Enhancements
9a5a48b7 131
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132XXX Changes which enhance performance without changing behaviour go here. There
133may well be none in a stable release.
9a5a48b7 134
34dc2ec0 135[ List each enhancement as a =item entry ]
9a5a48b7 136
34dc2ec0 137=over 4
c8c13991 138
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139=item *
140
34dc2ec0 141XXX
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142
143=back
144
34dc2ec0 145=head1 Modules and Pragmata
c8c13991 146
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147XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
148go here. If Module::CoreList is updated, generate an initial draft of the
149following sections using F<Porting/corelist-perldelta.pl>, which prints stub
150entries to STDOUT. Results can be pasted in place of the '=head2' entries
151below. A paragraph summary for important changes should then be added by hand.
152In an ideal world, dual-life modules would have a F<Changes> file that could be
153cribbed.
f00d3350 154
34dc2ec0 155[ Within each section, list entries as a =item entry ]
e9784f55 156
34dc2ec0 157=head2 New Modules and Pragmata
d430b8e7 158
34dc2ec0 159=over 4
d430b8e7 160
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161=item *
162
34dc2ec0 163XXX
31ecc2aa 164
e9784f55 165=back
c34a735e 166
34dc2ec0 167=head2 Updated Modules and Pragmata
24b164a5 168
34dc2ec0 169=over 4
2c389f6c 170
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171=item *
172
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173L<constant> has been updated from version 1.21 to 1.22.
174
175=item *
176
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177L<Archive::Extract> has been upgraded from version 0.48 to version 0.52
178
179Includes a fix for FreeBSD to only use C<unzip> if it is located in
180C</usr/local/bin>, as FreeBSD 9.0 will ship with a limited C<unzip> in
181C</usr/bin>.
182
183=item *
184
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185L<Attribute::Handlers> updated from version 0.88 to 0.91
186
187=item *
188
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189L<B> has been upgraded from version 1.29 to version 1.30.
190
191=item *
192
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193L<B::Deparse> has been upgraded from version 1.03 to 1.05.
194
195It addresses two regressions in Perl 5.14.0:
196
197=over
198
199=item *
200
201Deparsing of the C<glob> operator and its diamond (C<< <> >>) form now
202works again [RT #90898] (5.14.1).
203
204=item *
205
206The presence of subroutines named C<::::> or C<::::::> no longer causes
207B::Deparse to hang (5.14.1).
208
209=back
210
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211Plus a few other bugs:
212
213=over
214
215=item *
216
217Deparsing of handle C<keys>, C<each> and C<value> with a scalar argument
218now works [RT #91008].
219
220=item *
221
222C<readpipe> followed by a complex expression (as opposed to a simple scalar
223variable) now works.
224
225=item *
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226
227It now puts C<CORE::> in front of overridable core keywords if they
228conflict with user-defined subroutines.
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229
230=item *
231
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232Deparsing assignment to an lvalue method specified as a variable
233(C<< $obj->$method = ... >>) used not to work [RT #62498].
234
235=back
236
237=item *
238
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239L<CGI> has been upgraded from version 3.52 to version 3.54
240
241The DELETE HTTP verb is now supported.
242
243=item *
244
245L<Compress::Zlib> has been upgraded from version 2.033 to version 2.035
246
247=item *
248
249L<Compress::Raw::Bzip2> has been upgraded from version 2.033 to version 2.035
250
251=item *
252
253L<Compress::Raw::Zlib> has been upgraded from version 2.033 to version 2.035
254
255=item *
256
257L<CPAN::Meta> has been upgraded from version 2.110440 to version 2.110930
258
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259=item *
260
261L<CPANPLUS> has been upgraded from version 0.9103 to version 0.9105
262
263Now understands specifying modules to install in the format 'Module/Type.pm'
264
265=item *
266
267L<CPANPLUS::Dist::Build> has been upgraded from version 0.54 to version 0.56
268
269=item *
270
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271L<Data::Dumper> has been upgraded from version 2.128 to 2.131.
272
273=item *
274
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275L<DB_File> has been upgraded from version 1.821 to version 1.822
276
277Warnings are now in sync with perl's
278
279=item *
280
281L<Digest::SHA> has been upgraded from version 5.61 to version 5.62
282
283No longer loads L<MIME::Base64> as this was unnecessary.
284
285=item *
286
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287L<Devel::Peek> has been upgraded from version 1.07 to 1.08.
288
289Its C<fill_mstats> function no longer refuses to write to copy-on-write
290scalars.
291
292=item *
293
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294L<Encode> has been upgraded from version 2.42 to version 2.43
295
296Missing aliases added, a deep recursion error fixed and various
297documentation updates.
298
299=item *
300
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301L<ExtUtils::CBuilder> updated from version 0.280203 to 0.280204. The new version
302append CFLAGS and LDFLAGS to their Config.pm counterparts.
303
304=item *
305
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306L<Filter::Util::Call> has been upgraded from version 1.08 to version 1.39
307
308C<decrypt> fixed to work with v5.14.0
309
310=item *
311
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312L<Filter::Simple> updated from version 0.85 to 0.87
313
314=item *
315
316L<FindBin> updated from version 1.50 to 1.51.
317
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318It no longer returns a wrong result if a script of the same name as the
319current one exists in the path and is executable.
320
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321=item *
322
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323L<JSON::PP> has been upgraded from version 2.27105 to version 2.27200
324
325Fixed C<incr_parse> decoding string more correctly.
326
327=item *
328
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329L<I18N::LangTags> has been upgraded from version 0.35_01 to version 0.36.
330
331Fix broken URLs for RFCs.
332
333=item *
334
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335L<IPC::Open3> has been upgraded from version 1.10 to version 1.11.
336
337=over 4
338
339=item *
340
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341Fixes a bug which prevented use of C<open3> on Windows when C<*STDIN>,
342C<*STDOUT> or C<*STDERR> had been localized.
031f91ce 343
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344=item *
345
346Fixes a bug which prevented duplicating numeric file descriptors on Windows.
347
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348=back
349
350=item *
351
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352L<Math::BigFloat> has been upgraded from version 1.993 to 1.994.
353
354The C<numify> method has been corrected to return a normalised Perl number
355(the result of C<0 + $thing>), instead of a string [rt.cpan.org #66732].
356
357=item *
358
359L<Math::BigInt> has been upgraded from version 1.994 to 1.995.
360
361It provides a new C<bsgn> method that complements the C<babs> method.
362
363It fixes the internal C<objectify> function's handling of "foreign objects"
364so they are converted to the appropriate class (Math::BigInt or
365Math::BigFloat).
366
367=item *
368
f95396b3 369L<Math::Complex> has been upgraded from version 1.56 to version 1.57.
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370
371Correct copy constructor usage.
372Fix polarwise formatting with numeric format specifier.
373More stable C<great_circle_direction> algorithm.
374
375=item *
376
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377L<Module::CoreList> has been upgraded from version 2.49 to 2.50.
378
379Updated for v5.12.4.
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380
381=item *
382
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383L<mro> has been updated to remove two broken URLs in the documentation.
384
385=item *
386
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387L<Object::Accessor> has been upgraded from version 0.38 to version 0.42
388
389Eliminated use of C<exists> on array elements which has been deprecated.
390
391=item *
392
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393L<ODBM_File> has been upgraded from version 1.10 to version 1.11.
394
395The XS code is now compiled with C<PERL_NO_GET_CONTEXT>, which will aid
396performance under ithreads.
397
398=item *
399
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400L<PerlIO::encoding> has been upgraded from version 0.14 to 0.15
401
402=item *
403
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404L<PerlIO::scalar> has been upgraded from version 0.11 to 0.12.
405
406It fixes a problem with C<< open my $fh, ">", \$scalar >> not working if
407C<$scalar> is a copy-on-write scalar.
408
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409It also fixes a hang that occurs with C<readline> or C<< <$fh> >> if a
410typeglob has been assigned to $scalar [RT #92258].
411
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412=item *
413
99bdc4f8 414L<Pod::Perldoc> has been upgraded from version 3.15_03 to 3.15_05.
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415
416It corrects the search paths on VMS [RT #90640].
417
418=item *
419
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420L<Storable> has been upgraded from version 2.27 to version 2.28.
421
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422It no longer turns copy-on-write scalars into read-only scalars when
423freezing and thawing.
424
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425=item *
426
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427L<Sys::Syslog> has been upgraded from version 0.27 to version 0.29
428
429Large number of Request Tickets resolved.
430
431=item *
432
f95396b3 433L<Time::HiRes> has been upgraded from version 1.9721_01 to version 1.9722.
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434
435Portability fix, and avoiding some compiler warnings.
436
437=item *
438
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439L<Unicode::Collate> has been upgraded from version 0.73 to version 0.76
440
441Updated to CLDR 1.9.1
442
443=item *
444
445L<Unicode::Normalize> has been upgraded from version 1.10 to version 1.12
446
e879069a 447Fixes for the removal of F<unicore/CompositionExclusions.txt> from core.
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448
449=item *
450
451L<XSLoader> has been upgraded from version 0.13 to version 0.15
452
453Integrated changes from bleadperl
454
455=item *
456
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457L<charnames> can now be invoked with a new option, C<:loose>,
458which is like the existing C<:full> option, but enables Unicode loose
459name matching. This means that instead of
460having to get the name of the code point or sequence you want exactly right,
461you can fudge things somewhat. This is especially useful when
462you don't remember if the official Unicode name uses hyphens or
463blanks between words. Details are in L<charnames/LOOSE MATCHES>.
464
34dc2ec0 465XXX
9780b8fa 466
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467=back
468
34dc2ec0 469=head2 Removed Modules and Pragmata
bdb0cce8 470
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471As promised in Perl 5.14.0's release notes, the following modules have
472been removed from the core distribution, and if needed should be installed
473from CPAN instead.
474
475=over
44691e6f 476
5076a392 477=item *
44691e6f 478
e879069a 479L<Devel::DProf> has been removed from the Perl core. Prior version was 20110228.00.
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480
481=item *
482
e879069a 483L<Shell> has been removed from the Perl core. Prior version was 0.72_01.
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484
485=back
486
34dc2ec0 487=head1 Documentation
44691e6f 488
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489XXX Changes to files in F<pod/> go here. Consider grouping entries by
490file and be sure to link to the appropriate page, e.g. L<perlfunc>.
6d96b0fe 491
34dc2ec0 492=head2 New Documentation
6d96b0fe 493
34dc2ec0 494XXX Changes which create B<new> files in F<pod/> go here.
6d96b0fe 495
34dc2ec0 496=head3 L<XXX>
e8e35311 497
34dc2ec0 498XXX Description of the purpose of the new file here
6d96b0fe 499
34dc2ec0 500=head2 Changes to Existing Documentation
b7188eb5 501
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502XXX Changes which significantly change existing files in F<pod/> go here.
503However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
504section.
b7188eb5 505
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506=head3 L<perlfork>
507
508=over
509
510=item *
511
33ce5db2 512Added portability caveats related to using C<kill> on forked process.
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513
514=back
515
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516=head3 L<perlfunc>
517
518=over
519
520=item *
521
522C<given>, C<when> and C<default> are now listed in L<perlfunc> (5.14.1).
523
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524=item *
525
526The examples for the C<select> function no longer use strings for file
527handles.
528
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529=back
530
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531=head3 L<perlguts>
532
533=over
534
535=item *
536
537Some of the function descriptions in L<perlguts> were confusing, as it was
538not clear whether they referred to the function above or below the
539description. This has been clarified [RT #91790].
540
541=back
542
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543=head3 L<perllol>
544
545=over
546
547=item *
548
549L<perllol> has been expanded with examples using the new C<push $scalar>
550syntax introduced in Perl 5.14.0 (5.14.1).
551
552=back
553
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554=head3 L<perlmod>
555
556=over
557
558=item *
559
560L<perlmod> now states explicitly that some types of explicit symbol table
561manipulation are not supported. This codifies what was effectively already
562the case [RT #78074].
563
564=back
565
760696b8 566=head3 L<perlop>
b7188eb5 567
34dc2ec0 568=over 4
e8e35311 569
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570=item *
571
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572The explanation of bitwise operators has been expanded to explain how they
573work on Unicode strings (5.14.1).
574
575=item *
576
577The section on the triple-dot or yada-yada operator has been moved up, as
578it used to separate two closely related sections about the comma operator
579(5.14.1).
580
581=item *
582
583More examples for C<m//g> have been added (5.14.1).
584
585=item *
586
587The C<<< <<\FOO >>> here-doc syntax has been documented (5.14.1).
588
589=back
590
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591=head3 L<perlpodstyle>
592
593=over 4
594
595=item *
596
597The tips on which formatting codes to use have been corrected and greatly
598expanded.
599
600=item *
601
602There are now a couple of example one-liners for previewing POD files after
603they have been edited.
604
605=back
606
607=head3 L<perlre>
608
609=over
610
611=item *
612
613The C<(*COMMIT)> directive is now listed in the right section
614(L<Verbs without an argument|perlre/Verbs without an argument>).
615
616=back
617
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618=head3 L<perlrun>
619
620=over
621
622=item *
623
624L<perlrun> has undergone a significant clean-up. Most notably, the
625B<-0x...> form of the B<-0> flag has been clarified, and the final section
626on environment variables has been corrected and expanded (5.14.1).
2c389f6c 627
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628=back
629
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630=head3 L<perlvar>
631
632=over
633
634=item *
635
636The documentation for L<$!|perlvar/$!> has been corrected and clarified.
637It used to state that $! could be C<undef>, which is not the case. It was
638also unclear as to whether system calls set C's C<errno> or Perl's C<$!>
639[RT #91614].
640
641=back
642
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643=head3 L<POSIX>
644
645=over
646
647=item *
648
649The invocation documentation for C<WIFEXITED>, C<WEXITSTATUS>,
650C<WIFSIGNALED>, C<WTERMSIG>, C<WIFSTOPPED>, and C<WSTOPSIG> has been
651corrected (5.14.1).
652
653=back
654
34dc2ec0 655=head1 Diagnostics
b7188eb5 656
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657The following additions or changes have been made to diagnostic output,
658including warnings and fatal error messages. For the complete list of
659diagnostic messages, see L<perldiag>.
44691e6f 660
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661XXX New or changed warnings emitted by the core's C<C> code go here. Also
662include any changes in L<perldiag> that reconcile it to the C<C> code.
6c9cd4a1 663
34dc2ec0 664[ Within each section, list entries as a =item entry ]
6c9cd4a1 665
34dc2ec0 666=head2 New Diagnostics
44691e6f 667
34dc2ec0 668XXX Newly added diagnostic messages go here
44691e6f 669
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670=head3 New Warnings
671
34dc2ec0 672=over 4
44691e6f 673
bdab33d1 674=item L<Useless assignment to a temporary|perldiag/"Useless assignment to a temporary">
44691e6f 675
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676Assigning to a temporary returned from an XS lvalue subroutine now produces a
677warning [RT #31946].
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678
679=back
680
34dc2ec0 681=head2 Changes to Existing Diagnostics
b7188eb5 682
34dc2ec0 683XXX Changes (i.e. rewording) of diagnostic messages go here
b7188eb5 684
34dc2ec0 685=over 4
b7188eb5 686
5076a392 687=item *
b7188eb5 688
34dc2ec0 689XXX
b7188eb5 690
e8e35311 691=back
5076a392 692
34dc2ec0 693=head1 Utility Changes
5076a392 694
34dc2ec0
DM
695XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go
696here. Most of these are built within the directories F<utils> and F<x2p>.
5076a392 697
34dc2ec0
DM
698[ List utility changes as a =head3 entry for each utility and =item
699entries for each change
700Use L<XXX> with program names to get proper documentation linking. ]
5076a392 701
34dc2ec0 702=head3 L<XXX>
5076a392 703
34dc2ec0 704=over 4
5076a392
FC
705
706=item *
707
34dc2ec0 708XXX
5076a392 709
2c389f6c 710=back
e8e35311 711
34dc2ec0 712=head1 Configuration and Compilation
5076a392 713
34dc2ec0
DM
714XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
715go here. Any other changes to the Perl build process should be listed here.
716However, any platform-specific changes should be listed in the
717L</Platform Support> section, instead.
2c389f6c 718
34dc2ec0 719[ List changes as a =item entry ].
2c389f6c 720
34dc2ec0 721=over 4
5076a392 722
e8e35311 723=item *
5076a392 724
760696b8
FC
725F<regexp.h> has been modified for compatibility with GCC's B<-Werror>
726option, as used by some projects that include perl's header files (5.14.1).
5076a392 727
bdab33d1
DG
728=item *
729
730USE_LOCALE{,_COLLATE,_CTYPE,_NUMERIC} have been added the output of perl -V
731as they have affect the behaviour of the interpreter binary (albeit only
732in a small area).
733
1f8e9456
NC
734=item *
735
736The code and tests for L<IPC::Open2> have been moved from F<ext/IPC-Open2>
737into F<ext/IPC-Open3>, as C<IPC::Open2::open2()> is implemented as a thin
738wrapper around C<IPC::Open3::_open3()>, and hence is very tightly coupled to
739it.
740
34dc2ec0 741=back
5076a392 742
34dc2ec0 743=head1 Testing
5076a392 744
34dc2ec0
DM
745XXX Any significant changes to the testing of a freshly built perl should be
746listed here. Changes which create B<new> files in F<t/> go here as do any
747large changes to the testing harness (e.g. when parallel testing was added).
748Changes to existing files in F<t/> aren't worth summarising, although the bugs
749that they represent may be covered elsewhere.
5076a392 750
34dc2ec0 751[ List each test improvement as a =item entry ]
5076a392 752
34dc2ec0 753=over 4
5076a392
FC
754
755=item *
756
34dc2ec0 757XXX
e8e35311 758
34dc2ec0 759=back
5076a392 760
34dc2ec0 761=head1 Platform Support
5076a392 762
34dc2ec0 763XXX Any changes to platform support should be listed in the sections below.
5076a392 764
34dc2ec0
DM
765[ Within the sections, list each platform as a =item entry with specific
766changes as paragraphs below it. ]
5076a392 767
34dc2ec0 768=head2 New Platforms
5076a392 769
34dc2ec0
DM
770XXX List any platforms that this version of perl compiles on, that previous
771versions did not. These will either be enabled by new files in the F<hints/>
772directories, or new subdirectories and F<README> files at the top level of the
773source tree.
cdc10f43 774
34dc2ec0 775=over 4
cdc10f43 776
bdab33d1 777=item GNU/Hurd
d430b8e7 778
bdab33d1
DG
779=over
780
781=item *
782
783No longer overrides possible extra $ccflags values given to Configure
784on GNU/Hurd. C.f. Bug-Debian: http://bugs.debian.org/587901
785
786=back
787
788=item Mac OS X
789
33ce5db2 790Clarified apple developer tools requirements in F<README.macosx>
bdab33d1
DG
791
792=item MSWin32
793
794Supplied F<makefile.mk> patched to support gcc-4.x.x and README.win32
795updated accordingly. [RT #91354]
796
797=item Solaris
798
799Updated the list of required packages for building perl to reflect Solaris 9
800and 10 in README.solaris [RT #90850]
d430b8e7 801
2c389f6c 802=back
5076a392 803
34dc2ec0 804=head2 Discontinued Platforms
5076a392 805
34dc2ec0 806XXX List any platforms that this version of perl no longer compiles on.
5076a392 807
34dc2ec0 808=over 4
e8e35311 809
34dc2ec0 810=item XXX-some-platform
e8e35311 811
34dc2ec0 812XXX
1e463951 813
c71a852f 814=back
b7188eb5 815
34dc2ec0 816=head2 Platform-Specific Notes
42a91c97 817
34dc2ec0
DM
818XXX List any changes for specific platforms. This could include configuration
819and compilation changes or changes in portability/compatibility. However,
820changes within modules for platforms should generally be listed in the
821L</Modules and Pragmata> section.
42a91c97 822
6693394d
FC
823=head3 Ubuntu Linux
824
34dc2ec0 825=over 4
42a91c97 826
6693394d 827=item *
42a91c97 828
6693394d
FC
829The L<ODBM_File> installation process has been updated with the new library
830paths on Ubuntu natty [RT #90106].
831
832=item *
833
834I<h2ph> now gets the include paths from gcc correctly. This stopped
835working when Ubuntu switched to a "multiarch" setup [RT #90122].
42a91c97 836
34dc2ec0 837=back
42a91c97 838
34dc2ec0 839=head1 Internal Changes
42a91c97 840
34dc2ec0
DM
841XXX Changes which affect the interface available to C<XS> code go here.
842Other significant internal changes for future core maintainers should
843be noted as well.
42a91c97 844
34dc2ec0 845=over 4
42a91c97 846
2c389f6c
FC
847=item *
848
c13a5c80
NC
849When empting a hash of its elements (e.g. via undef(%h), or %h=()), HvARRAY
850field is no longer temporarily zeroed. Any destructors called on the freed
851elements see the remaining elements. Thus, %h=() becomes more like C<delete
852$h{$_} for keys %h>.
853
854=item *
855
33ce5db2
NC
856The compiled representation of formats is now stored via the C<mg_ptr> of
857their C<PERL_MAGIC_fm>. Previously it was stored in the string buffer,
858beyond C<SvLEN()>, the regular end of the string. C<SvCOMPILED()> and
859C<SvCOMPILED_{on,off}()> now exist solely for compatibility for XS code.
74e0ddf7 860The first is always 0, the other two now no-ops.
cdc10f43 861
bdab33d1
DG
862=item *
863
c13a5c80 864Boyer-Moore compiled scalars are now PVMGs, and the Boyer-Moore tables are now
33ce5db2
NC
865stored via the mg_ptr of their C<PERL_MAGIC_bm>. Previously they were PVGVs,
866with the tables stored in the string buffer, beyond C<SvLEN()>. This eliminates
867the last place where the core stores data beyond C<SvLEN()>.
bdab33d1 868
571f0e86
NC
869=item *
870
384e62c0
DG
871Simplified logic in C<Perl_sv_magic()> introduces a small change of
872behaviour for error cases involving unknown magic types. Previously, if
873C<Perl_sv_magic()> was passed a magic type unknown to it, it would
874
875=over
876
877=item 1.
878
879Croak "Modification of a read-only value attempted" if read only
880
881=item 2.
882
883Return without error if the SV happened to already have this magic
884
885=item 3.
886
887otherwise croak "Don't know how to handle magic of type \\%o"
888
889=back
890
891Now it will always croak "Don't know how to handle magic of type \\%o", even
892on read only values, or SVs which already have the unknown magic type.
893
34dc2ec0 894=back
cdc10f43 895
34dc2ec0 896=head1 Selected Bug Fixes
cdc10f43 897
34dc2ec0
DM
898XXX Important bug fixes in the core language are summarised here.
899Bug fixes in files in F<ext/> and F<lib/> are best summarised in
900L</Modules and Pragmata>.
cdc10f43 901
34dc2ec0 902[ List each fix as a =item entry ]
d430b8e7 903
bdab33d1
DG
904=head2 Regular expressions and character classes
905
34dc2ec0 906=over 4
d430b8e7
FC
907
908=item *
909
f7a45dff
KW
910The new (in 5.14.0) regular expression modifier C</a> when repeated like
911C</aa> forbids the characters outside the ASCII range that match
912characters inside that range from matching under C</i>. This did not
913work under some circumstances, all involving alternation, such as:
914
915 "\N{KELVIN SIGN}" =~ /k|foo/iaa;
916
6693394d 917succeeded inappropriately. This is now fixed.
f7a45dff
KW
918
919=item *
920
9215.14.0 introduced some memory leaks in regular expression character
bdab33d1 922classes such as C<[\w\s]>, which have now been fixed
f7a45dff
KW
923
924=item *
925
926An edge case in regular expression matching could potentially loop.
927This happened only under C</i> in bracketed character classes that have
928characters with multi-character folds, and the target string to match
929against includes the first portion of the fold, followed by another
930character that has a multi-character fold that begins with the remaining
931portion of the fold, plus some more.
932
933 "s\N{U+DF}" =~ /[\x{DF}foo]/i
934
bdab33d1 935is one such case. C<\xDF> folds to C<"ss">
f7a45dff
KW
936
937=item *
938
939A few characters in regular expression pattern matches did not
940match correctly in some circumstances, all involving C</i>. The
941affected characters are:
942COMBINING GREEK YPOGEGRAMMENI,
943GREEK CAPITAL LETTER IOTA,
944GREEK CAPITAL LETTER UPSILON,
945GREEK PROSGEGRAMMENI,
946GREEK SMALL LETTER IOTA WITH DIALYTIKA AND OXIA,
947GREEK SMALL LETTER IOTA WITH DIALYTIKA AND TONOS,
948GREEK SMALL LETTER UPSILON WITH DIALYTIKA AND OXIA,
949GREEK SMALL LETTER UPSILON WITH DIALYTIKA AND TONOS,
950LATIN SMALL LETTER LONG S,
951LATIN SMALL LIGATURE LONG S T,
952and
953LATIN SMALL LIGATURE ST.
d430b8e7 954
2fbb14a0
DG
955=item *
956
bdab33d1
DG
957Fixed memory leak regression in regular expression compilation
958under threading
959
960=back
961
962=head2 Formats
963
f5938650
FC
964=over
965
966=item *
967
968A number of edge cases have been fixed with formats and C<formline>;
2fbb14a0
DG
969in particular, where the format itself is potentially variable (such as
970with ties and overloading), and where the format and data differ in their
971encoding. In both these cases, it used to possible for the output to be
f5938650
FC
972corrupted [RT #91032].
973
974=item *
975
976C<formline> no longer converts its argument into a string in-place. So
977passing a reference to C<formline> no longer destroys the reference
978[RT #79532].
979
980=back
2fbb14a0 981
bdab33d1 982=head2 Copy-on-write scalars
975dff8c 983
33ce5db2 984Copy-on-write scalars were introduced in 5.8.0, but most Perl code
6693394d
FC
985did not encounter them (they were used mostly internally). Perl
9865.10.0 extended them, such that assigning C<__PACKAGE__> or a
987hash key to a scalar would make it copy-on-write. Several parts
bdab33d1 988of Perl were not updated to account for them, but have now been fixed.
975dff8c
FC
989
990=over
991
992=item *
993
994C<utf8::decode> had a nasty bug that would modify copy-on-write scalars'
995string buffers in place (i.e., skipping the copy). This could result in
996hashes having two elements with the same key [RT #91834].
997
998=item *
999
1000Lvalue subroutines were not allowing COW scalars to be returned. This was
1001fixed for lvalue scalar context in Perl 5.12.3 and 5.14.0, but list context
1002was not fixed until this release.
1003
1004=item *
1005
1006Elements of restricted hashes (see the L<fields> pragma) containing
1007copy-on-write values couldn't be deleted, nor could such hashes be cleared
1008(C<%hash = ()>).
1009
1010=item *
1011
1012Localising a tied variable used to make it read-only if it contained a
1013copy-on-write string.
1014
1015=item *
1016
1017L<Storable>, L<Devel::Peek> and L<PerlIO::scalar> had similar problems.
1018See L</Updated Modules and Pragmata>, above.
1019
1020=back
1021
bdab33d1 1022=head2 lvalue subroutines
975dff8c 1023
bdab33d1 1024There have been various fixes to lvalue subroutines.
975dff8c
FC
1025
1026=over
1027
1028=item *
1029
1030Explicit return now returns the actual argument passed to return, instead
f5938650
FC
1031of copying it [RT #72724] [RT #72706].
1032
1033B<Note:> There are still some discrepancies between explicit and implicit
1034return, which will hopefully be resolved soon. So the exact behaviour is
1035not set in stone yet.
975dff8c
FC
1036
1037=item *
1038
1039Lvalue subroutines used to enforce lvalue syntax (i.e., whatever can go on
1040the left-hand side of C<=>) for the last statement and the arguments to
1041return. Since lvalue subroutines are not always called in lvalue context,
1042this restriction has been lifted.
1043
1044=item *
1045
1046Lvalue subroutines are less restrictive as to what values can be returned.
1047It used to croak on values returned by C<shift> and C<delete> and from
f5938650 1048other subroutines, but no longer does so [RT #71172].
975dff8c
FC
1049
1050=item *
1051
1052Empty lvalue subroutines (C<sub :lvalue {}>) used to return C<@_> in list
1053context. In fact, all subroutines used to, but regular subs were fixed in
1054Perl 5.8.2. Now lvalue subroutines have been likewise fixed.
1055
1056=item *
1057
1058Lvalue subroutines used to copy their return values in rvalue context. Not
1059only was this a waste of CPU cycles, but it also caused bugs. A C<($)>
f5938650 1060prototype would cause an lvalue sub to copy its return value [RT #51408],
975dff8c
FC
1061and C<while(lvalue_sub() =~ m/.../g) { ... }> would loop endlessly
1062[RT #78680].
1063
1064=item *
1065
1066Autovivification now works on values returned from lvalue subroutines
1067[RT #7946].
1068
1069=item *
1070
bdab33d1
DG
1071When called in pass-by-reference context (e.g., subroutine arguments or a list
1072passed to C<for>), an lvalue subroutine returning arrays or hashes used to bind
1073the arrays (or hashes) to scalar variables--something that is not supposed to
87d00a71
FC
1074happen. This could result in "Bizarre copy of ARRAY" errors or C<print>
1075ignoring its arguments. It also made nonsensical code like C<@{\$_}> "work".
bdab33d1
DG
1076This was fixed in 5.14.0 if an array were the first thing returned from the
1077subroutine (but not for C<$scalar, @array> or hashes being returned). Now a
1078more general fix has been applied [RT #23790].
975dff8c 1079
fad4a2e4
FC
1080=item *
1081
da507230
FC
1082When called in pass-by-reference context, lvalue subroutines used to copy
1083any read-only value that were returned. E.g., C< sub :lvalue { $] } >
1084would not return C<$]>, but a copy of it.
1085
1086=item *
1087
fad4a2e4
FC
1088Assignment to C<keys> returned from an lvalue sub used not to work, but now
1089it does.
1090
4dbb339a
FC
1091=item *
1092
1093Applying the C<:lvalue> attribute to an XSUB or to an aliased subroutine
1094stub with C<< sub foo :lvalue; >> syntax stopped working in Perl 5.12.
1095This has been fixed.
1096
975dff8c
FC
1097=back
1098
6693394d 1099=head2 Fixes related to hashes
bdab33d1
DG
1100
1101=over
1102
1103=item *
1104
1105A bug has been fixed that would cause a "Use of freed value in iteration"
1106error if the next two hash elements that would be iterated over are
6693394d
FC
1107deleted [RT #85026].
1108
1109=item *
1110
1111Freeing deeply nested hashes no longer crashes [RT #44225].
1112
1113=item *
1114
1115Deleting the current hash iterator (the hash element that would be returend
1116by the next call to C<each>) in void context used not to free it. The hash
1117would continue to reference it until the next iteration. This has been
1118fixed [RT #85026].
1119
1120=back
1121
1122=head2 Other notable fixes
1123
1124=over
bdab33d1
DG
1125
1126=item *
1127
1128Passing the same constant subroutine to both C<index> and C<formline> no
1129longer causes one or the other to fail [RT #89218].
1130
f5d1ed10
FC
1131=item *
1132
1133List assignment to lexical variables declared with attributes in the same
1134statement (C<my ($x,@y) : blimp = (72,94)>) stopped working in Perl 5.8.0.
1135It has now been fixed.
1136
bdab33d1
DG
1137=item *
1138
6693394d
FC
1139Perl 5.10.0 introduced some faulty logic that made "U*" in the middle of
1140a pack template equivalent to "U0" if the input string was empty. This has
1141been fixed [RT #90160].
1142
1143=item *
1144
1145Destructors on objects were not called during global destruction on objects
1146that were not referenced by any scalars. This could happen if an array
1147element were blessed (e.g., C<bless \$a[0]>) or if a closure referenced a
1148blessed variable (C<bless \my @a; sub foo { @a }>).
1149
1150Now there is an extra pass during global destruction to fire destructors on
1151any objects that might be left after the usual passes that check for
1152objects referenced by scalars [RT #36347].
1153
1154This bug fix was added in Perl 5.13.9, but caused problems with some CPAN
1155modules that were relying on the bug. Since it was so close to Perl
11565.14.0, the fix was reverted in 5.13.10, to allow more time for the modules
1157to adapt. Hopefully they will be fixed soon (see L</Known Problems>,
1158below).
1159
1160=item *
1161
1162C<given> was not calling set-magic on the implicit lexical C<$_> that it
1163uses. This meant, for example, that C<pos> would be remembered from one
1164execution of the same C<given> block to the next, even if the input were a
1165different variable [RT #84526].
1166
1167=item *
1168
1169The "R" command for restarting a debugger session has been fixed to work on
1170Windows, or any other system lacking a C<POSIX::_SC_OPEN_MAX> constant
1171[RT #87740].
1172
1173=item *
1174
1175Fixed a case where it was possible that a freed buffer may have been read
1176from when parsing a here document [RT #90128].
1177
1178=item *
1179
1180The C<study> function could become confused if fed a string longer than
11812**31 characters. Now it simply skips such strings.
1182
1183=item *
1184
1185C<each(I<ARRAY>)> is now wrapped in C<defined(...)>, like C<each(I<HASH>)>,
1186inside a C<when> condition [RT #90888].
bdab33d1 1187
f5938650
FC
1188=item *
1189
1190In @INC filters (subroutines returned by subroutines in @INC), $_ used to
1191misbehave: If returned from a subroutine, it would not be copied, but the
1192variable itself would be returned; and freeing $_ (e.g., with C<undef *_>)
1193would cause perl to crash. This has been fixed [RT #91880].
1194
1195=item *
1196
1197An ASCII single quote (') in a symbol name is meant to be equivalent to a
1198double colon (::) except at the end of the name. It was not equivalent if
1199followed by a null character, but now it is [RT #88138].
1200
25aa614d
KW
1201=item *
1202
1203The abbreviations for four C1 control characters
1204C<MW>
1205C<PM>,
1206C<RI>,
1207and
1208C<ST>
1209were previously unrecognized by C<\N{}>,
1210vianame(), and string_vianame().
1211
87d00a71
FC
1212=item *
1213
1214Some cases of threads crashing due to memory allocation during cloning have
1215been fixed [RT #90006].
1216
1217=item *
1218
1219Attempting to C<goto> out of a tied handle method used to cause memory
1220corruption or crashes. Now it produces an error message instead
1221[RT #8611].
1222
da507230
FC
1223=item *
1224
1225Perl skips copying values returned from a subroutine if it thinks the value
1226is not in use elsewhere. Due to faulty logic, this would happen with the
1227result of C<delete>, C<shift> or C<splice>, even if the result was
1228referenced elsewhere. So C<< \sub { delete $_[0] }->($x) >> would return a
e03ef783 1229reference to C<$x>. This has been fixed [RT #91844].
da507230 1230
42a91c97
FC
1231=back
1232
bdab33d1
DG
1233=head2 Additional fixes by ticket number
1234
1235XXX Prefix these with "\n=item *\n" once the list is final
1236
bdab33d1
DG
1237Fixed RT #88822: Test failure t/re_fold_grind.t with bleadperl
1238Fixed RT #89896: Locale::Maketext test failure
6693394d 1239
f5938650 1240XXX Comments from FC: I do not think these two are necessary.
bdab33d1 1241
c71a852f 1242=head1 Known Problems
44691e6f 1243
34dc2ec0
DM
1244XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
1245tests that had to be C<TODO>ed for the release would be noted here, unless
1246they were specific to a particular platform (see below).
cdc10f43 1247
34dc2ec0
DM
1248This is a list of some significant unfixed bugs, which are regressions
1249from either 5.XXX.XXX or 5.XXX.XXX.
cdc10f43 1250
34dc2ec0 1251[ List each fix as a =item entry ]
ca767864 1252
34dc2ec0 1253=over 4
cf5da40b
CB
1254
1255=item *
1256
6693394d
FC
1257The fix for RT #36347 causes test failures for C<Gtk2> and C<Tk> on some
1258systems [RT #82542].
cf5da40b 1259
bda24d5c
FC
1260=item *
1261
1262The changes to C<tie> cause test failures for the C<JS> module.
1263
c71a852f 1264=back
014fb485 1265
c71a852f 1266=head1 Obituary
014fb485 1267
34dc2ec0
DM
1268XXX If any significant core contributor has died, we've added a short obituary
1269here.
44691e6f 1270
44691e6f
AB
1271=head1 Acknowledgements
1272
34dc2ec0 1273XXX The list of people to thank goes here.
29cf780c 1274
44691e6f
AB
1275=head1 Reporting Bugs
1276
1277If you find what you think is a bug, you might check the articles
34dc2ec0 1278recently posted to the comp.lang.perl.misc newsgroup and the perl
44691e6f
AB
1279bug database at http://rt.perl.org/perlbug/ . There may also be
1280information at http://www.perl.org/ , the Perl Home Page.
1281
1282If you believe you have an unreported bug, please run the L<perlbug>
1283program included with your release. Be sure to trim your bug down
1284to a tiny but sufficient test case. Your bug report, along with the
1285output of C<perl -V>, will be sent off to perlbug@perl.org to be
1286analysed by the Perl porting team.
1287
1288If the bug you are reporting has security implications, which make it
1289inappropriate to send to a publicly archived mailing list, then please send
34dc2ec0 1290it to perl5-security-report@perl.org. This points to a closed subscription
461d5f13 1291unarchived mailing list, which includes all the core committers, who are able
44691e6f
AB
1292to help assess the impact of issues, figure out a resolution, and help
1293co-ordinate the release of patches to mitigate or fix the problem across all
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DM
1294platforms on which Perl is supported. Please only use this address for
1295security issues in the Perl core, not for modules independently
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1296distributed on CPAN.
1297
1298=head1 SEE ALSO
1299
1300The F<Changes> file for an explanation of how to view exhaustive details
1301on what changed.
1302
1303The F<INSTALL> file for how to build Perl.
1304
1305The F<README> file for general stuff.
1306
1307The F<Artistic> and F<Copying> files for copyright information.
1308
1309=cut