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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. ]
eabfc7bc 7
1b510166 8perldelta - what is new for perl v5.27.1
89853d76 9
b5cbfe35 10=head1 DESCRIPTION
89853d76 11
1b510166 12This document describes differences between the 5.27.0 release and the 5.27.1
b5cbfe35 13release.
89853d76 14
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15If you are upgrading from an earlier release such as 5.26.0, first read
16L<perl5270delta>, which describes differences between 5.26.0 and 5.27.0.
17
18=head1 Notice
19
20XXX Any important notices here
21
22=head1 Core Enhancements
23
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
28[ List each enhancement as a =head2 entry ]
29
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30=head2 L<C<delete>|perlfunc/delete EXPR> on key/value slices
31
32L<C<delete>|perlfunc/delete EXPR> can now be used on key/value slices,
33returning the keys along with the deleted values.
34L<[perl #131328]|https://rt.perl.org/Ticket/Display.html?id=131328>
35
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36=head1 Security
37
38XXX Any security-related notices go here. In particular, any security
39vulnerabilities closed should be noted here rather than in the
40L</Selected Bug Fixes> section.
41
42[ List each security issue as a =head2 entry ]
43
44=head1 Incompatible Changes
45
46XXX For a release on a stable branch, this section aspires to be:
47
48 There are no changes intentionally incompatible with 5.XXX.XXX
49 If any exist, they are bugs, and we request that you submit a
50 report. See L</Reporting Bugs> below.
51
52[ List each incompatible change as a =head2 entry ]
53
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54=head2 Comma-less variable lists in formats are no longer allowed
55
56Omitting the commas between variables passed to formats is no longer
1cf41740 57allowed. This has been deprecated since Perl 5.000.
c7321345 58
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59=head2 The C<:locked> and C<:unique> attributes have been removed
60
1cf41740 61These have been no-ops and deprecated since Perl 5.12 and 5.10,
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62respectively.
63
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64=head2 C<\N{}> with nothing between the braces is now illegal.
65
66This has been deprecated since Perl 5.24.
67
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68=head2 Opening the same symbol as both a file and directory handle is no longer allowed
69
70Using open() and opendir() to associate both a filehandle and a dirhandle
71to the same symbol (glob or scalar) has been deprecated since Perl 5.10.
72
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73=head2 Use of bare C<< << >> to mean C<< <<"" >> is no longer allowed
74
75Use of a bare terminator has been deprecated since Perl 5.000.
76
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77=head1 Deprecations
78
79XXX Any deprecated features, syntax, modules etc. should be listed here.
80
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81=head2 Use of L<C<vec>|perlfunc/vec EXPR,OFFSET,BITS> on strings with code
82points above 0xFF is deprecated.
83
84Use of these is nonsensical, as C<vec> is a bit-oriented operation,
85which operates on the underlying UTF-8 representation these strings must
86be in, and will likely give unexpected results.
87
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88=head2 Some uses of unescaped C<"{"> are no longer fatal
89
90Perl 5.26.0 fatalized some uses of an unescaped left brace, but an
91exception was made at the last minute, specifically crafted to be a
92minimal change to allow GNU Autoconf to work. This code is heavily
93depended upon, and continues to use the deprecated usage. Its use of an
94unescaped left brace is one where we have no intention of repurposing
95C<"{"> to be something other than itself.
96
97That exception is now generalized to include various other such cases
98where the C<"{"> will not be repurposed. This is to get real experience
99with this more complicated change now, in case we need to issue a dot
100release if we find other things like Autoconf that are important to work
101around.
102
103Note that these uses continue to raise a deprecation message.
104
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105=head2 Module removals
106
107XXX Remove this section if inapplicable.
108
109The following modules will be removed from the core distribution in a
110future release, and will at that time need to be installed from CPAN.
111Distributions on CPAN which require these modules will need to list them as
112prerequisites.
113
114The core versions of these modules will now issue C<"deprecated">-category
115warnings to alert you to this fact. To silence these deprecation warnings,
116install the modules in question from CPAN.
117
118Note that these are (with rare exceptions) fine modules that you are encouraged
119to continue to use. Their disinclusion from core primarily hinges on their
120necessity to bootstrapping a fully functional, CPAN-capable Perl installation,
121not usually on concerns over their design.
122
123=over
124
125=item XXX
126
127XXX Note that deprecated modules should be listed here even if they are listed
128as an updated module in the L</Modules and Pragmata> section.
129
130=back
131
132[ List each other deprecation as a =head2 entry ]
133
134=head1 Performance Enhancements
135
136XXX Changes which enhance performance without changing behaviour go here.
137There may well be none in a stable release.
138
139[ List each enhancement as a =item entry ]
140
141=over 4
142
143=item *
144
145XXX
146
147=back
16beba24 148
b5cbfe35 149=head1 Modules and Pragmata
2c8edc25 150
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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>. A paragraph summary
154for important changes should then be added by hand. In an ideal world,
155dual-life modules would have a F<Changes> file that could be cribbed.
156
157[ Within each section, list entries as a =item entry ]
158
159=head2 New Modules and Pragmata
160
161=over 4
162
163=item *
164
165XXX
166
167=back
168
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169=head2 Updated Modules and Pragmata
170
171=over 4
fbe3f407 172
759020c9 173=item *
7ca0bfc4 174
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175L<XXX> has been upgraded from version A.xx to B.yy.
176
177=back
178
179=head2 Removed Modules and Pragmata
180
181=over 4
182
183=item *
184
185XXX
186
187=back
188
189=head1 Documentation
190
191XXX Changes to files in F<pod/> go here. Consider grouping entries by
192file and be sure to link to the appropriate page, e.g. L<perlfunc>.
193
194=head2 New Documentation
195
196XXX Changes which create B<new> files in F<pod/> go here.
197
198=head3 L<XXX>
199
200XXX Description of the purpose of the new file here
201
202=head2 Changes to Existing Documentation
203
204XXX Changes which significantly change existing files in F<pod/> go here.
205However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
206section.
207
208=head3 L<XXX>
209
210=over 4
a049258c 211
2c8edc25 212=item *
d5c7a4fc 213
1b510166 214XXX Description of the change here
a049258c 215
b5cbfe35 216=back
3abe9611 217
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218=head1 Diagnostics
219
220The following additions or changes have been made to diagnostic output,
221including warnings and fatal error messages. For the complete list of
222diagnostic messages, see L<perldiag>.
223
224XXX New or changed warnings emitted by the core's C<C> code go here. Also
225include any changes in L<perldiag> that reconcile it to the C<C> code.
226
227=head2 New Diagnostics
228
229XXX Newly added diagnostic messages go under here, separated into New Errors
230and New Warnings
231
232=head3 New Errors
233
234=over 4
235
236=item *
237
238XXX L<message|perldiag/"message">
239
240=back
241
242=head3 New Warnings
243
244=over 4
245
246=item *
247
248XXX L<message|perldiag/"message">
249
250=back
251
252=head2 Changes to Existing Diagnostics
253
254XXX Changes (i.e. rewording) of diagnostic messages go here
255
256=over 4
257
258=item *
259
260XXX Describe change here
261
262=back
0cc8c746 263
1b510166 264=head1 Utility Changes
0cc8c746 265
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266XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go here.
267Most of these are built within the directory F<utils>.
0cc8c746 268
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269[ List utility changes as a =head2 entry for each utility and =item
270entries for each change
271Use L<XXX> with program names to get proper documentation linking. ]
0cc8c746 272
1b510166 273=head2 L<XXX>
0cc8c746 274
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275=over 4
276
277=item *
278
279XXX
280
281=back
282
283=head1 Configuration and Compilation
284
285XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
286go here. Any other changes to the Perl build process should be listed here.
287However, any platform-specific changes should be listed in the
288L</Platform Support> section, instead.
289
290[ List changes as a =item entry ].
291
292=over 4
293
294=item *
295
296XXX
297
298=back
299
300=head1 Testing
301
302XXX Any significant changes to the testing of a freshly built perl should be
303listed here. Changes which create B<new> files in F<t/> go here as do any
304large changes to the testing harness (e.g. when parallel testing was added).
305Changes to existing files in F<t/> aren't worth summarizing, although the bugs
306that they represent may be covered elsewhere.
307
308[ List each test improvement as a =item entry ]
309
310=over 4
311
312=item *
313
314XXX
315
316=back
317
318=head1 Platform Support
319
320XXX Any changes to platform support should be listed in the sections below.
321
322[ Within the sections, list each platform as a =item entry with specific
323changes as paragraphs below it. ]
324
325=head2 New Platforms
326
327XXX List any platforms that this version of perl compiles on, that previous
328versions did not. These will either be enabled by new files in the F<hints/>
329directories, or new subdirectories and F<README> files at the top level of the
330source tree.
331
332=over 4
333
334=item XXX-some-platform
335
336XXX
337
338=back
339
340=head2 Discontinued Platforms
341
342XXX List any platforms that this version of perl no longer compiles on.
343
344=over 4
345
346=item XXX-some-platform
347
348XXX
349
350=back
351
352=head2 Platform-Specific Notes
353
354XXX List any changes for specific platforms. This could include configuration
355and compilation changes or changes in portability/compatibility. However,
356changes within modules for platforms should generally be listed in the
357L</Modules and Pragmata> section.
358
359=over 4
360
361=item XXX-some-platform
362
363XXX
364
365=back
366
367=head1 Internal Changes
368
369XXX Changes which affect the interface available to C<XS> code go here. Other
370significant internal changes for future core maintainers should be noted as
371well.
372
373[ List each change as a =item entry ]
374
375=over 4
376
377=item *
378
7e30e49f 379The C<PL_statbuf> interpreter variable has been removed.
1b510166 380
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381=item *
382
383The deprecated function C<to_utf8_case()>, accessible from XS code, has
384been removed.
385
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386=back
387
388=head1 Selected Bug Fixes
389
390XXX Important bug fixes in the core language are summarized here. Bug fixes in
391files in F<ext/> and F<lib/> are best summarized in L</Modules and Pragmata>.
392
393[ List each fix as a =item entry ]
394
395=over 4
396
397=item *
398
399XXX
400
401=back
402
403=head1 Known Problems
404
405XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
406tests that had to be C<TODO>ed for the release would be noted here. Unfixed
407platform specific bugs also go here.
408
409[ List each fix as a =item entry ]
410
411=over 4
412
413=item *
414
415XXX
416
417=back
418
419=head1 Errata From Previous Releases
420
421=over 4
422
423=item *
424
425XXX Add anything here that we forgot to add, or were mistaken about, in
426the perldelta of a previous release.
427
428=back
429
430=head1 Obituary
431
432XXX If any significant core contributor has died, we've added a short obituary
433here.
434
435=head1 Acknowledgements
0cc8c746 436
1b510166 437XXX Generate this with:
2e0dcc12 438
1b510166 439 perl Porting/acknowledgements.pl v5.25.5..HEAD
f5b73711 440
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441=head1 Reporting Bugs
442
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443If you find what you think is a bug, you might check the perl bug database
444at L<https://rt.perl.org/> . There may also be information at
445L<http://www.perl.org/> , the Perl Home Page.
44691e6f 446
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447If you believe you have an unreported bug, please run the L<perlbug> program
448included with your release. Be sure to trim your bug down to a tiny but
449sufficient test case. Your bug report, along with the output of C<perl -V>,
b5cbfe35 450will be sent off to perlbug@perl.org to be analysed by the Perl porting team.
44691e6f 451
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452If the bug you are reporting has security implications which make it
453inappropriate to send to a publicly archived mailing list, then see
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454L<perlsec/SECURITY VULNERABILITY CONTACT INFORMATION>
455for details of how to report the issue.
44691e6f 456
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457=head1 Give Thanks
458
459If you wish to thank the Perl 5 Porters for the work we had done in Perl 5,
460you can do so by running the C<perlthanks> program:
461
462 perlthanks
463
464This will send an email to the Perl 5 Porters list with your show of thanks.
465
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466=head1 SEE ALSO
467
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468The F<Changes> file for an explanation of how to view exhaustive details on
469what changed.
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470
471The F<INSTALL> file for how to build Perl.
472
473The F<README> file for general stuff.
474
475The F<Artistic> and F<Copying> files for copyright information.
476
477=cut