This is a live mirror of the Perl 5 development currently hosted at https://github.com/perl/perl5
Upgrade autodie from version 2.28 to 2.29
[perl5.git] / pod / perldelta.pod
CommitLineData
44691e6f
AB
1=encoding utf8
2
3=head1 NAME
4
fc4c3cec
RS
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 v5.23.1
eabfc7bc 9
2cfe9b50 10=head1 DESCRIPTION
eabfc7bc 11
fc4c3cec 12This document describes differences between the 5.23.0 release and the 5.23.1
2cfe9b50 13release.
eabfc7bc 14
fc4c3cec
RS
15If you are upgrading from an earlier release such as 5.22.0, first read
16L<perl5230delta>, which describes differences between 5.22.0 and 5.23.0.
17
18=head1 Notice
19
20XXX Any important notices here
21
2cfe9b50 22=head1 Core Enhancements
eabfc7bc 23
fc4c3cec
RS
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.
ac71d2a0 27
fc4c3cec 28[ List each enhancement as a =head2 entry ]
ac71d2a0 29
deaaea8c
JH
30=head2 Integer shift (C<< << >> and C<< >> >>) now explicitly defined
31
32Negative shifts are reverse shifts: left shift becomes right shift,
33and right shift becomes left shift.
34
35Shifting by the number of bits in a native integer (or more) is zero,
36except when the "overshift" is right shifting a negative value under
37C<use integer>, in which case the result is -1 (arithmetic shift).
38
39Until now negative shifting and overshifting have been undefined
40because they have relied on whatever the C implementation happens
41to do. For example, for the "overshift" a common behavior C is
42"modulo shift":
43
44 1 >> 64 == 1 >> (64 % 64) == 1 >> 0 == 1 # Common C behavior.
45
46 # And the same for <<, while Perl now produces 0 for both.
47
48Now these behaviors are well-defined under Perl, regardless of what
49the underlying C implementation does. Note, however, that you cannot
50escape the native integer width. If you need more bits on the left shift,
51you could use the C<bigint> pragma.
52
7d380357
RS
53=head2 Postfix dereferencing is no longer experimental
54
1c2511e0
AC
55Using the C<postderef> and C<postderef_qq> features no longer emits a
56warning. Existing code that disables the C<experimental::postderef> warning
57category that they previously used will continue to work. The C<postderef>
58feature has no effect; all Perl code can use postfix dereferencing,
59regardless of what feature declarations are in scope. The C<5.24> feature
60bundle now includes the C<postderef_qq> feature.
7d380357 61
fc4c3cec 62=head1 Security
2ad792cd 63
fc4c3cec
RS
64XXX Any security-related notices go here. In particular, any security
65vulnerabilities closed should be noted here rather than in the
66L</Selected Bug Fixes> section.
67
68[ List each security issue as a =head2 entry ]
2ad792cd 69
2cfe9b50 70=head1 Incompatible Changes
eabfc7bc 71
ce4793f1
KW
72=head2 ASCII characters in variable names must now be all visible
73
74It was legal until now on ASCII platforms for variable names to contain
75non-graphical ASCII control characters (ordinals 0 through 31, and 127,
76which are the C0 controls and C<DELETE>). This usage has been
77deprecated since v5.20, and as of now causes a syntax error. The
78variables these names referred to are special, reserved by Perl for
79whatever use it may choose, now, or in the future. Each such variable
80has an alternative way of spelling it. Instead of the single
81non-graphic control character, a two character sequence beginning with a
82caret is used, like C<$^]> and C<${^GLOBAL_PHASE}>. Details are at
83L<perlvar>. It remains legal, though unwise and deprecated (raising a
84deprecation warning), to use certain non-graphic non-ASCII characters in
85variables names when not under S<C<use utf8>>. No code should do this,
86as all such variables are reserved by Perl, and Perl doesn't currently
87define any of them (but could at any time, without notice).
eabfc7bc 88
26230909
AC
89=head2 The C<autoderef> feature has been removed
90
91The experimental C<autoderef> feature (which allowed calling C<push>,
92C<pop>, C<shift>, C<unshift>, C<splice>, C<keys>, C<values>, and C<each> on
93a scalar argument) has been deemed unsuccessful. It has now been removed;
94trying to use the feature (or to disable the C<experimental::autoderef>
95warning it previously triggered) now yields an exception.
96
fc4c3cec 97=head1 Deprecations
eabfc7bc 98
fc4c3cec 99XXX Any deprecated features, syntax, modules etc. should be listed here.
eabfc7bc 100
fc4c3cec
RS
101=head2 Module removals
102
103XXX Remove this section if inapplicable.
104
105The following modules will be removed from the core distribution in a
106future release, and will at that time need to be installed from CPAN.
107Distributions on CPAN which require these modules will need to list them as
108prerequisites.
109
110The core versions of these modules will now issue C<"deprecated">-category
111warnings to alert you to this fact. To silence these deprecation warnings,
112install the modules in question from CPAN.
113
114Note that these are (with rare exceptions) fine modules that you are encouraged
115to continue to use. Their disinclusion from core primarily hinges on their
116necessity to bootstrapping a fully functional, CPAN-capable Perl installation,
117not usually on concerns over their design.
118
119=over
120
121=item XXX
122
123XXX Note that deprecated modules should be listed here even if they are listed
124as an updated module in the L</Modules and Pragmata> section.
125
126=back
127
128[ List each other deprecation as a =head2 entry ]
129
130=head1 Performance Enhancements
131
132XXX Changes which enhance performance without changing behaviour go here.
133There may well be none in a stable release.
134
135[ List each enhancement as a =item entry ]
eabfc7bc 136
73d6481e 137=over 4
eabfc7bc 138
73d6481e 139=item *
eabfc7bc 140
fc4c3cec 141XXX
eabfc7bc 142
fc4c3cec 143=back
eabfc7bc 144
fc4c3cec 145=head1 Modules and Pragmata
eabfc7bc 146
fc4c3cec
RS
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>. A paragraph summary
150for important changes should then be added by hand. In an ideal world,
151dual-life modules would have a F<Changes> file that could be cribbed.
eabfc7bc 152
fc4c3cec 153[ Within each section, list entries as a =item entry ]
eabfc7bc 154
fc4c3cec 155=head2 New Modules and Pragmata
eabfc7bc 156
fc4c3cec 157=over 4
eabfc7bc 158
73d6481e 159=item *
eabfc7bc 160
fc4c3cec 161XXX
eabfc7bc 162
fc4c3cec 163=back
eabfc7bc 164
fc4c3cec
RS
165=head2 Updated Modules and Pragmata
166
167=over 4
eabfc7bc
RS
168
169=item *
170
dc013420
SH
171L<autodie> has been upgraded from version 2.28 to 2.29.
172
173=item *
174
c85f23b2
DD
175L<IPC::Open3> has been upgraded from version 1.18 to 1.19.
176
177If a Perl exception was thrown from inside this module, the exception
779c45ce 178C<IPC::Open3> threw to the callers of C<open3> would have an irrelevant
c85f23b2
DD
179message derived from C<$!> which was in an undefined state, instead of the
180C<$@> message which triggers the failure path inside C<open3>.
eabfc7bc 181
fc4c3cec
RS
182=back
183
184=head2 Removed Modules and Pragmata
eabfc7bc 185
fc4c3cec 186=over 4
374c951f
SH
187
188=item *
189
fc4c3cec 190XXX
e586de20 191
fc4c3cec 192=back
e586de20 193
fc4c3cec 194=head1 Documentation
fd0a842f 195
fc4c3cec
RS
196XXX Changes to files in F<pod/> go here. Consider grouping entries by
197file and be sure to link to the appropriate page, e.g. L<perlfunc>.
fd0a842f 198
fc4c3cec 199=head2 New Documentation
99527ef1 200
fc4c3cec 201XXX Changes which create B<new> files in F<pod/> go here.
99527ef1 202
fc4c3cec 203=head3 L<XXX>
a4f8ff46 204
fc4c3cec 205XXX Description of the purpose of the new file here
a4f8ff46 206
fc4c3cec 207=head2 Changes to Existing Documentation
73d6481e 208
fc4c3cec
RS
209XXX Changes which significantly change existing files in F<pod/> go here.
210However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
211section.
212
213=head3 L<XXX>
73d6481e 214
fc4c3cec 215=over 4
eabfc7bc
RS
216
217=item *
218
fc4c3cec 219XXX Description of the change here
b7b593d8 220
fc4c3cec 221=back
b7b593d8 222
fc4c3cec 223=head1 Diagnostics
b7b593d8 224
fc4c3cec
RS
225The following additions or changes have been made to diagnostic output,
226including warnings and fatal error messages. For the complete list of
227diagnostic messages, see L<perldiag>.
b7b593d8 228
fc4c3cec
RS
229XXX New or changed warnings emitted by the core's C<C> code go here. Also
230include any changes in L<perldiag> that reconcile it to the C<C> code.
b7b593d8 231
fc4c3cec 232=head2 New Diagnostics
b7b593d8 233
fc4c3cec
RS
234XXX Newly added diagnostic messages go under here, separated into New Errors
235and New Warnings
b7b593d8 236
fc4c3cec
RS
237=head3 New Errors
238
239=over 4
eabfc7bc 240
ef5cf9f5
TC
241=item *
242
fc4c3cec 243XXX L<message|perldiag/"message">
72b8c7a2 244
fc4c3cec 245=back
72b8c7a2 246
fc4c3cec
RS
247=head3 New Warnings
248
249=over 4
bdb6acef
SH
250
251=item *
252
fc4c3cec 253XXX L<message|perldiag/"message">
ef5cf9f5 254
fc4c3cec 255=back
3d58dd24 256
fc4c3cec
RS
257=head2 Changes to Existing Diagnostics
258
259XXX Changes (i.e. rewording) of diagnostic messages go here
260
261=over 4
4b951711
TC
262
263=item *
264
fc4c3cec 265XXX Describe change here
eabfc7bc 266
fc4c3cec 267=back
eabfc7bc 268
fc4c3cec 269=head1 Utility Changes
eabfc7bc 270
fc4c3cec
RS
271XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go here.
272Most of these are built within the directory F<utils>.
eabfc7bc 273
fc4c3cec
RS
274[ List utility changes as a =head2 entry for each utility and =item
275entries for each change
276Use L<XXX> with program names to get proper documentation linking. ]
eabfc7bc 277
fc4c3cec
RS
278=head2 L<XXX>
279
280=over 4
eabfc7bc
RS
281
282=item *
283
fc4c3cec 284XXX
eabfc7bc 285
fc4c3cec 286=back
eabfc7bc 287
fc4c3cec 288=head1 Configuration and Compilation
eabfc7bc 289
fc4c3cec
RS
290XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
291go here. Any other changes to the Perl build process should be listed here.
292However, any platform-specific changes should be listed in the
293L</Platform Support> section, instead.
eabfc7bc 294
fc4c3cec 295[ List changes as a =item entry ].
eabfc7bc 296
fc4c3cec 297=over 4
eabfc7bc
RS
298
299=item *
300
fc4c3cec 301XXX
eabfc7bc 302
fc4c3cec 303=back
eabfc7bc 304
fc4c3cec 305=head1 Testing
eabfc7bc 306
fc4c3cec
RS
307XXX Any significant changes to the testing of a freshly built perl should be
308listed here. Changes which create B<new> files in F<t/> go here as do any
309large changes to the testing harness (e.g. when parallel testing was added).
310Changes to existing files in F<t/> aren't worth summarizing, although the bugs
311that they represent may be covered elsewhere.
312
313[ List each test improvement as a =item entry ]
314
315=over 4
eabfc7bc 316
fc4c3cec 317=item *
eabfc7bc 318
fc4c3cec 319XXX
eabfc7bc 320
2cfe9b50 321=back
33ca8d3c 322
73d6481e 323=head1 Platform Support
eabfc7bc 324
fc4c3cec 325XXX Any changes to platform support should be listed in the sections below.
eabfc7bc 326
fc4c3cec
RS
327[ Within the sections, list each platform as a =item entry with specific
328changes as paragraphs below it. ]
eabfc7bc 329
fc4c3cec 330=head2 New Platforms
42fe7840 331
fc4c3cec
RS
332XXX List any platforms that this version of perl compiles on, that previous
333versions did not. These will either be enabled by new files in the F<hints/>
334directories, or new subdirectories and F<README> files at the top level of the
335source tree.
336
337=over 4
42fe7840 338
fc4c3cec
RS
339=item XXX-some-platform
340
341XXX
42fe7840
CB
342
343=back
344
fc4c3cec 345=head2 Discontinued Platforms
eabfc7bc 346
fc4c3cec 347XXX List any platforms that this version of perl no longer compiles on.
269713a1 348
fc4c3cec 349=over 4
269713a1 350
fc4c3cec 351=item XXX-some-platform
269713a1 352
fc4c3cec 353XXX
463e63a4 354
fc4c3cec 355=back
463e63a4 356
fc4c3cec 357=head2 Platform-Specific Notes
9c0328ac 358
fc4c3cec
RS
359XXX List any changes for specific platforms. This could include configuration
360and compilation changes or changes in portability/compatibility. However,
361changes within modules for platforms should generally be listed in the
362L</Modules and Pragmata> section.
9c0328ac 363
fc4c3cec
RS
364=over 4
365
7d380357 366=item VMS
fc4c3cec 367
7d380357
RS
368=over
369
370=item *
371
372The minimum supported version of VMS is now v7.3-2, released in 2003. As a
373side effect of this change, VAX is no longer supported as the terminal
374release of OpenVMS VAX was v7.3 in 2001.
375
376=back
eabfc7bc 377
2cfe9b50 378=back
eabfc7bc 379
fc4c3cec
RS
380=head1 Internal Changes
381
382XXX Changes which affect the interface available to C<XS> code go here. Other
383significant internal changes for future core maintainers should be noted as
384well.
385
386[ List each change as a =item entry ]
eabfc7bc 387
2cfe9b50 388=over 4
eabfc7bc
RS
389
390=item *
391
fc4c3cec 392XXX
eabfc7bc 393
fc4c3cec 394=back
302ef3d4 395
fc4c3cec 396=head1 Selected Bug Fixes
302ef3d4 397
fc4c3cec
RS
398XXX Important bug fixes in the core language are summarized here. Bug fixes in
399files in F<ext/> and F<lib/> are best summarized in L</Modules and Pragmata>.
eabfc7bc 400
fc4c3cec
RS
401[ List each fix as a =item entry ]
402
403=over 4
eabfc7bc 404
73d6481e 405=item *
eabfc7bc 406
7ed1d857
DD
407A leak in the XS typemap caused one scalar to be leaked each time a C<FILE *>
408or a C<PerlIO *> was C<OUTPUT:>ed or imported to Perl, since perl 5.000. These
409particular typemap entries are thought to be extremely rarely used by XS
410modules. [perl #124181]
eabfc7bc 411
fc4c3cec
RS
412=back
413
414=head1 Known Problems
415
416XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
417tests that had to be C<TODO>ed for the release would be noted here. Unfixed
418platform specific bugs also go here.
419
420[ List each fix as a =item entry ]
eabfc7bc 421
fc4c3cec
RS
422=over 4
423
424=item *
eabfc7bc 425
fc4c3cec 426XXX
eabfc7bc 427
73d6481e 428=back
eabfc7bc 429
fc4c3cec 430=head1 Errata From Previous Releases
eabfc7bc 431
fc4c3cec 432=over 4
eabfc7bc 433
fc4c3cec 434=item *
2a7a05b4 435
fc4c3cec
RS
436XXX Add anything here that we forgot to add, or were mistaken about, in
437the perldelta of a previous release.
30aa8e3f 438
fc4c3cec 439=back
30aa8e3f 440
fc4c3cec
RS
441=head1 Obituary
442
443XXX If any significant core contributor has died, we've added a short obituary
444here.
445
446=head1 Acknowledgements
2a7a05b4 447
fc4c3cec 448XXX Generate this with:
2cfe9b50 449
fc4c3cec 450 perl Porting/acknowledgements.pl v5.23.1..HEAD
f5b73711 451
44691e6f
AB
452=head1 Reporting Bugs
453
e08634c5
SH
454If you find what you think is a bug, you might check the articles recently
455posted to the comp.lang.perl.misc newsgroup and the perl bug database at
fc4c3cec
RS
456L<https://rt.perl.org/> . There may also be information at
457L<http://www.perl.org/> , the Perl Home Page.
44691e6f 458
e08634c5
SH
459If you believe you have an unreported bug, please run the L<perlbug> program
460included with your release. Be sure to trim your bug down to a tiny but
461sufficient test case. Your bug report, along with the output of C<perl -V>,
462will be sent off to perlbug@perl.org to be analysed by the Perl porting team.
44691e6f
AB
463
464If the bug you are reporting has security implications, which make it
e08634c5
SH
465inappropriate to send to a publicly archived mailing list, then please send it
466to perl5-security-report@perl.org. This points to a closed subscription
467unarchived mailing list, which includes all the core committers, who will be
468able to help assess the impact of issues, figure out a resolution, and help
f9001595 469co-ordinate the release of patches to mitigate or fix the problem across all
e08634c5
SH
470platforms on which Perl is supported. Please only use this address for
471security issues in the Perl core, not for modules independently distributed on
472CPAN.
44691e6f
AB
473
474=head1 SEE ALSO
475
e08634c5
SH
476The F<Changes> file for an explanation of how to view exhaustive details on
477what changed.
44691e6f
AB
478
479The F<INSTALL> file for how to build Perl.
480
481The F<README> file for general stuff.
482
483The F<Artistic> and F<Copying> files for copyright information.
484
485=cut