This is a live mirror of the Perl 5 development currently hosted at https://github.com/perl/perl5
perldelta for 27c6f44
[perl5.git] / pod / perldelta.pod
CommitLineData
44691e6f
AB
1=encoding utf8
2
3=head1 NAME
4
e96e0834
JL
5[ this is a template for a new perldelta file. Any text flagged as
6XXX needs to be processed before release. ]
27f00e3d 7
e96e0834 8perldelta - what is new for perl v5.17.2
417a992d 9
e96e0834 10=head1 DESCRIPTION
028c8719 11
e96e0834
JL
12This document describes differences between the 5.17.1 release and
13the 5.17.2 release.
028c8719 14
e96e0834
JL
15If you are upgrading from an earlier release such as 5.17.0, first read
16L<perl5171delta>, which describes differences between 5.17.0 and
175.17.1.
028c8719 18
e96e0834 19=head1 Notice
30608892 20
e96e0834 21XXX Any important notices here
e128ab2c 22
e96e0834 23=head1 Core Enhancements
e128ab2c 24
e96e0834
JL
25XXX New core language features go here. Summarise user-visible core language
26enhancements. Particularly prominent performance optimisations could go
27here, but most should go in the L</Performance Enhancements> section.
fe3193b5 28
e96e0834 29[ List each enhancement as a =head2 entry ]
05c8f9ed 30
e96e0834 31=head1 Security
0da72d5e 32
e96e0834
JL
33XXX Any security-related notices go here. In particular, any security
34vulnerabilities closed should be noted here rather than in the
35L</Selected Bug Fixes> section.
0da72d5e 36
e96e0834 37[ List each security issue as a =head2 entry ]
0da72d5e 38
e96e0834 39=head1 Incompatible Changes
0da72d5e 40
e96e0834 41XXX For a release on a stable branch, this section aspires to be:
0da72d5e 42
e96e0834
JL
43 There are no changes intentionally incompatible with 5.XXX.XXX
44 If any exist, they are bugs, and we request that you submit a
45 report. See L</Reporting Bugs> below.
0da72d5e 46
e96e0834 47[ List each incompatible change as a =head2 entry ]
e2f0c3bb 48
e96e0834 49=head1 Deprecations
e2f0c3bb 50
e96e0834
JL
51XXX Any deprecated features, syntax, modules etc. should be listed here.
52In particular, deprecated modules should be listed here even if they are
53listed as an updated module in the L</Modules and Pragmata> section.
7d101ed1 54
e96e0834 55[ List each deprecation as a =head2 entry ]
7d101ed1 56
e96e0834 57=head1 Performance Enhancements
7d101ed1 58
e96e0834
JL
59XXX Changes which enhance performance without changing behaviour go here. There
60may well be none in a stable release.
7d101ed1 61
e96e0834 62[ List each enhancement as a =item entry ]
95ce428c 63
f9001595 64=over 4
75ff5956 65
2630d42b 66=item *
c11980ad 67
e96e0834 68XXX
53de3ff0 69
61174fb5 70=back
ef7131e9 71
61174fb5 72=head1 Modules and Pragmata
ef7131e9 73
e96e0834
JL
74XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
75go here. If Module::CoreList is updated, generate an initial draft of the
76following sections using F<Porting/corelist-perldelta.pl>, which prints stub
77entries to STDOUT. Results can be pasted in place of the '=head2' entries
78below. A paragraph summary for important changes should then be added by hand.
79In an ideal world, dual-life modules would have a F<Changes> file that could be
80cribbed.
5cefbec9 81
e96e0834 82[ Within each section, list entries as a =item entry ]
fbdb83f3 83
e96e0834 84=head2 New Modules and Pragmata
95c6c5c5 85
e96e0834 86=over 4
9331f04e
NC
87
88=item *
89
e96e0834 90XXX
95c6c5c5 91
e96e0834 92=back
ff3f295c 93
e96e0834 94=head2 Updated Modules and Pragmata
ff3f295c 95
e96e0834 96=over 4
95c6c5c5 97
95c6c5c5
JL
98=item *
99
4c77591b
NC
100L<File::stat> has been upgraded from version 1.06 to 1.07.
101
102Previously C<File::stat>'s overloaded C<-x> and C<-X> operators did not give
103the correct results for directories or executable files when running as
104root. They had been treating executable permissions for root just like for
105any other user, performing group membership tests I<etc> for files not owned
106by root. They now follow the correct Unix behaviour - for a directory they
107are always true, and for a file if any of the three execute permission bits
108are set then they report that root can execute the file. Perl's builtin
109C<-x> and C<-X> operators have always been correct.
c506fc7e 110
36ab1671
FC
111=item *
112
113L<Tie::StdHandle> has been upgraded from version 4.2 to 4.3.
114
115C<READ> now respects the offset argument to C<read> [perl #112826].
116
e96e0834 117=back
c506fc7e 118
e96e0834 119=head2 Removed Modules and Pragmata
c506fc7e 120
e96e0834 121=over 4
95c6c5c5 122
95c6c5c5
JL
123=item *
124
e96e0834 125XXX
95c6c5c5 126
e96e0834 127=back
95c6c5c5 128
e96e0834 129=head1 Documentation
95c6c5c5 130
e96e0834
JL
131XXX Changes to files in F<pod/> go here. Consider grouping entries by
132file and be sure to link to the appropriate page, e.g. L<perlfunc>.
95c6c5c5 133
e96e0834 134=head2 New Documentation
1c633914 135
e96e0834 136XXX Changes which create B<new> files in F<pod/> go here.
f558db2f 137
e96e0834 138=head3 L<XXX>
66aa79e2 139
e96e0834 140XXX Description of the purpose of the new file here
95c6c5c5 141
e96e0834 142=head2 Changes to Existing Documentation
95c6c5c5 143
e96e0834
JL
144XXX Changes which significantly change existing files in F<pod/> go here.
145However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
146section.
95c6c5c5 147
e96e0834 148=head3 L<XXX>
95c6c5c5 149
e96e0834 150=over 4
95c6c5c5
JL
151
152=item *
153
e96e0834 154XXX Description of the change here
95c6c5c5 155
e96e0834 156=back
95c6c5c5 157
e96e0834 158=head1 Diagnostics
95c6c5c5 159
e96e0834
JL
160The following additions or changes have been made to diagnostic output,
161including warnings and fatal error messages. For the complete list of
162diagnostic messages, see L<perldiag>.
95c6c5c5 163
e96e0834
JL
164XXX New or changed warnings emitted by the core's C<C> code go here. Also
165include any changes in L<perldiag> that reconcile it to the C<C> code.
71014848 166
e96e0834
JL
167[ Within each section, list entries as a =item entry that links to perldiag,
168 e.g.
71014848 169
e96e0834 170 =item *
95c6c5c5 171
e96e0834
JL
172 L<Invalid version object|perldiag/"Invalid version object">
173]
95c6c5c5 174
e96e0834 175=head2 New Diagnostics
95c6c5c5 176
e96e0834 177XXX Newly added diagnostic messages go here
95c6c5c5 178
e96e0834 179=head3 New Errors
95c6c5c5 180
e96e0834 181=over 4
95c6c5c5 182
95c6c5c5
JL
183=item *
184
a9be10f4 185L<Group name must start with a non-digit word character in regex; marked by <-- HERE in mE<sol>%sE<sol>|perldiag/"Group name must start with a non-digit word character in regex; marked by <-- HERE in m/%s/">
40e43b78
FC
186
187This error has been added for C<(?&0)>, which is invalid. It used to
188produce an incomprehensible error message [perl #101666].
95c6c5c5 189
e96e0834 190=back
95c6c5c5 191
e96e0834 192=head3 New Warnings
95c6c5c5 193
e96e0834 194=over 4
95c6c5c5 195
95c6c5c5
JL
196=item *
197
72267260
JL
198C<chr()> now warns when passed a negative value [perl #83048].
199
200=item *
201
202C<srand()> now warns when passed a value that doesn't fit in a C<UV> (since the
203value will be truncated rather than overflowing) [perl #40605].
7d101ed1 204
e013ada0
JL
205=item *
206
207Running perl with the C<-i> flag now warns if no input files are provided on
208the command line [perl #113410].
209
e96e0834 210=back
d9661073 211
e96e0834 212=head2 Changes to Existing Diagnostics
95c6c5c5 213
e96e0834 214XXX Changes (i.e. rewording) of diagnostic messages go here
95c6c5c5 215
e96e0834 216=over 4
95c6c5c5
JL
217
218=item *
219
e96e0834 220XXX Describe change here
3630f57e 221
e96e0834 222=back
3630f57e 223
e96e0834 224=head1 Utility Changes
95c6c5c5 225
e96e0834
JL
226XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go
227here. Most of these are built within the directories F<utils> and F<x2p>.
95c6c5c5 228
e96e0834
JL
229[ List utility changes as a =head3 entry for each utility and =item
230entries for each change
231Use L<XXX> with program names to get proper documentation linking. ]
95c6c5c5 232
e96e0834 233=head3 L<XXX>
95c6c5c5 234
e96e0834 235=over 4
95c6c5c5
JL
236
237=item *
238
e96e0834 239XXX
95c6c5c5 240
e96e0834 241=back
95c6c5c5 242
e96e0834 243=head1 Configuration and Compilation
95c6c5c5 244
e96e0834
JL
245XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
246go here. Any other changes to the Perl build process should be listed here.
247However, any platform-specific changes should be listed in the
248L</Platform Support> section, instead.
95c6c5c5 249
e96e0834 250[ List changes as a =item entry ].
95c6c5c5 251
e96e0834 252=over 4
95c6c5c5
JL
253
254=item *
255
c5057b0f
FC
256Building perl with some Windows compilers used to fail due to a problem
257with miniperl's C<glob> operator (which uses the C<perlglob> program)
258deleting the PATH environment variable [perl #113798].
95c6c5c5 259
81b820f9
FC
260=item *
261
262C<delete local> no longer crashes with certain magical arrays and hashes
263[perl #112966].
264
265=item *
266
267C<local> on elements of certain magical arrays and hashes used not to
268arrange to have the element deleted on scope exit, even if the element did
269not exist before C<local>.
270
1db1b2e4
FC
271=item *
272
273C<scalar(write)> no longer returns multiple items [perl #73690].
274
e013ada0
JL
275=item *
276
277String to floating point conversions no longer misparse certain strings under
278C<use locale> [perl #109318].
279
280=item *
281
282C<@INC> filters that die no longer leak memory [perl #92252].
283
284=item *
285
286The implementations of overloaded operations are now called in the correct
287context. This allows, among other things, being able to properly override
288C<< <> >> [perl #47119].
289
56185adc
JL
290=item *
291
292Specifying only the C<fallback> key when calling C<use overload> now behaves
293properly [perl #113010].
294
e96e0834 295=back
95c6c5c5 296
e96e0834 297=head1 Testing
95c6c5c5 298
e96e0834
JL
299XXX Any significant changes to the testing of a freshly built perl should be
300listed here. Changes which create B<new> files in F<t/> go here as do any
301large changes to the testing harness (e.g. when parallel testing was added).
302Changes to existing files in F<t/> aren't worth summarising, although the bugs
303that they represent may be covered elsewhere.
95c6c5c5 304
e96e0834 305[ List each test improvement as a =item entry ]
95c6c5c5 306
e96e0834 307=over 4
95c6c5c5
JL
308
309=item *
310
e96e0834 311XXX
95c6c5c5 312
61174fb5 313=back
f558db2f 314
e96e0834 315=head1 Platform Support
05c8f9ed 316
e96e0834 317XXX Any changes to platform support should be listed in the sections below.
05c8f9ed 318
e96e0834
JL
319[ Within the sections, list each platform as a =item entry with specific
320changes as paragraphs below it. ]
9dea6244 321
e96e0834 322=head2 New Platforms
9dea6244 323
e96e0834
JL
324XXX List any platforms that this version of perl compiles on, that previous
325versions did not. These will either be enabled by new files in the F<hints/>
326directories, or new subdirectories and F<README> files at the top level of the
327source tree.
7d101ed1
JL
328
329=over 4
330
e96e0834 331=item XXX-some-platform
7d101ed1 332
e96e0834 333XXX
7d101ed1
JL
334
335=back
336
e96e0834 337=head2 Discontinued Platforms
ef7131e9 338
e96e0834 339XXX List any platforms that this version of perl no longer compiles on.
4a301309
FC
340
341=over 4
342
e96e0834 343=item XXX-some-platform
8dffc0ab 344
e96e0834 345XXX
dbc84d79 346
4a301309
FC
347=back
348
61174fb5 349=head2 Platform-Specific Notes
ceb0881c 350
e96e0834
JL
351XXX List any changes for specific platforms. This could include configuration
352and compilation changes or changes in portability/compatibility. However,
353changes within modules for platforms should generally be listed in the
354L</Modules and Pragmata> section.
89cbc6b8 355
e96e0834 356=over 4
0998713f 357
e96e0834 358=item XXX-some-platform
112b6866 359
e96e0834 360XXX
112b6866 361
61174fb5 362=back
8e125188 363
61174fb5 364=head1 Internal Changes
8e125188 365
e96e0834
JL
366XXX Changes which affect the interface available to C<XS> code go here.
367Other significant internal changes for future core maintainers should
368be noted as well.
c4643160 369
e96e0834 370[ List each change as a =item entry ]
f8ef51fd 371
e96e0834 372=over 4
e128ab2c 373
e2f0c3bb
FC
374=item *
375
e96e0834 376XXX
e2f0c3bb 377
61174fb5 378=back
422287bf 379
61174fb5 380=head1 Selected Bug Fixes
2de6ba8d 381
e96e0834
JL
382XXX Important bug fixes in the core language are summarised here.
383Bug fixes in files in F<ext/> and F<lib/> are best summarised in
384L</Modules and Pragmata>.
52c4b146 385
e96e0834 386[ List each fix as a =item entry ]
e128ab2c
DM
387
388=over 4
389
390=item *
391
48895a0d
KW
392A regression introduced in v5.14.0 has been fixed, in which some calls
393to the C<re> module would clobber C<$_>.
e128ab2c 394
8b1adbab
JL
395=item *
396
397C<do FILE> now always either sets or clears C<$@>, even when the file can't be
398read. This ensures that testing C<$@> first (as recommended by the
399documentation) always returns the correct result.
400
83f29afa
VP
401=item *
402
403The array iterator used for the C<each @array> construct is now correctly
404reset when C<@array> is cleared (RT #75596). This happens for example when the
405array is globally assigned to, as in C<@array = (...)>, but not when its
406B<values> are assigned to. In terms of the XS API, it means that C<av_clear()>
407will now reset the iterator.
408
409This mirrors the behaviour of the hash iterator when the hash is cleared.
410
0938f143
JL
411=item *
412
413C<< $class->can >>, C<< $class->isa >>, and C<< $class->DOES >> now return
414correct results, regardless of whether that package referred to by C<$class>
415exists [perl #47113].
416
72267260
JL
417=item *
418
419Arriving signals no longer clear C<$@> [perl #45173].
420
7a251f7a
JL
421=item *
422
423Allow C<my ()> declarations with an empty variable list [perl #113554].
424
21247d85
FC
425=item *
426
427During parsing, subs declared after errors no longer leave stubs
428[perl #113712].
429
2e4f8b82
FC
430=item *
431
c95d4104
FC
432Closures containing no string evals no longer hang on to their containing
433subroutines, allowing variables closed over by outer subroutines to be
434freed when the outer sub is freed, even if the inner sub still exists
435[perl #89544].
436
788505db
FC
437=item *
438
439Duplication of in-memory filehandles by opening with a "<&=" or ">&=" mode
440stopped working properly in 5.16.0. It was causing the new handle to
441reference a different scalar variable. This has been fixed [perl #113764].
442
2c2b9cf4
FC
443=item *
444
445C<qr//> expressions no longer crash with custom regular expression engines
446that do not set C<offs> at regular expression compilation time
447[perl #112962].
448
e128ab2c
DM
449=back
450
e96e0834 451=head1 Known Problems
dbc84d79 452
e96e0834
JL
453XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
454tests that had to be C<TODO>ed for the release would be noted here. Unfixed
455platform specific bugs also go here.
53de3ff0 456
e96e0834 457[ List each fix as a =item entry ]
233bba44
JL
458
459=over 4
460
461=item *
462
e96e0834 463XXX
233bba44 464
e96e0834 465=back
233bba44 466
e96e0834 467=head1 Obituary
233bba44 468
e96e0834
JL
469XXX If any significant core contributor has died, we've added a short obituary
470here.
233bba44 471
61174fb5 472=head1 Acknowledgements
d5dc7001 473
e96e0834
JL
474XXX Generate this with:
475
476 perl Porting/acknowledgements.pl v5.17.1..HEAD
29cf780c 477
44691e6f
AB
478=head1 Reporting Bugs
479
480If you find what you think is a bug, you might check the articles
52deee2e 481recently posted to the comp.lang.perl.misc newsgroup and the perl
f9001595
RS
482bug database at http://rt.perl.org/perlbug/ . There may also be
483information at http://www.perl.org/ , the Perl Home Page.
44691e6f
AB
484
485If you believe you have an unreported bug, please run the L<perlbug>
52deee2e
DR
486program included with your release. Be sure to trim your bug down
487to a tiny but sufficient test case. Your bug report, along with the
488output of C<perl -V>, will be sent off to perlbug@perl.org to be
489analysed by the Perl porting team.
44691e6f
AB
490
491If the bug you are reporting has security implications, which make it
f9001595
RS
492inappropriate to send to a publicly archived mailing list, then please send
493it to perl5-security-report@perl.org. This points to a closed subscription
494unarchived mailing list, which includes
495all the core committers, who will be able
496to help assess the impact of issues, figure out a resolution, and help
497co-ordinate the release of patches to mitigate or fix the problem across all
498platforms on which Perl is supported. Please only use this address for
499security issues in the Perl core, not for modules independently
500distributed on CPAN.
44691e6f
AB
501
502=head1 SEE ALSO
503
52deee2e
DR
504The F<Changes> file for an explanation of how to view exhaustive details
505on what changed.
44691e6f
AB
506
507The F<INSTALL> file for how to build Perl.
508
509The F<README> file for general stuff.
510
511The F<Artistic> and F<Copying> files for copyright information.
512
513=cut