5 [ this is a template for a new perldelta file. Any text flagged as
6 XXX needs to be processed before release. ]
8 perldelta - what is new for perl v5.17.2
12 This document describes differences between the 5.17.1 release and
15 If you are upgrading from an earlier release such as 5.17.0, first read
16 L<perl5171delta>, which describes differences between 5.17.0 and
21 XXX Any important notices here
23 =head1 Core Enhancements
25 XXX New core language features go here. Summarise user-visible core language
26 enhancements. Particularly prominent performance optimisations could go
27 here, but most should go in the L</Performance Enhancements> section.
29 [ List each enhancement as a =head2 entry ]
33 XXX Any security-related notices go here. In particular, any security
34 vulnerabilities closed should be noted here rather than in the
35 L</Selected Bug Fixes> section.
37 [ List each security issue as a =head2 entry ]
39 =head1 Incompatible Changes
41 XXX For a release on a stable branch, this section aspires to be:
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.
47 [ List each incompatible change as a =head2 entry ]
51 XXX Any deprecated features, syntax, modules etc. should be listed here.
52 In particular, deprecated modules should be listed here even if they are
53 listed as an updated module in the L</Modules and Pragmata> section.
55 [ List each deprecation as a =head2 entry ]
57 =head1 Performance Enhancements
59 XXX Changes which enhance performance without changing behaviour go here. There
60 may well be none in a stable release.
62 [ List each enhancement as a =item entry ]
72 =head1 Modules and Pragmata
74 XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
75 go here. If Module::CoreList is updated, generate an initial draft of the
76 following sections using F<Porting/corelist-perldelta.pl>, which prints stub
77 entries to STDOUT. Results can be pasted in place of the '=head2' entries
78 below. A paragraph summary for important changes should then be added by hand.
79 In an ideal world, dual-life modules would have a F<Changes> file that could be
82 [ Within each section, list entries as a =item entry ]
84 =head2 New Modules and Pragmata
94 =head2 Updated Modules and Pragmata
100 L<File::stat> has been upgraded from version 1.06 to 1.07.
102 Previously C<File::stat>'s overloaded C<-x> and C<-X> operators did not give
103 the correct results for directories or executable files when running as
104 root. They had been treating executable permissions for root just like for
105 any other user, performing group membership tests I<etc> for files not owned
106 by root. They now follow the correct Unix behaviour - for a directory they
107 are always true, and for a file if any of the three execute permission bits
108 are set then they report that root can execute the file. Perl's builtin
109 C<-x> and C<-X> operators have always been correct.
113 L<Tie::StdHandle> has been upgraded from version 4.2 to 4.3.
115 C<READ> now respects the offset argument to C<read> [perl #112826].
119 =head2 Removed Modules and Pragmata
131 XXX Changes to files in F<pod/> go here. Consider grouping entries by
132 file and be sure to link to the appropriate page, e.g. L<perlfunc>.
134 =head2 New Documentation
136 XXX Changes which create B<new> files in F<pod/> go here.
140 XXX Description of the purpose of the new file here
142 =head2 Changes to Existing Documentation
144 XXX Changes which significantly change existing files in F<pod/> go here.
145 However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
154 XXX Description of the change here
160 The following additions or changes have been made to diagnostic output,
161 including warnings and fatal error messages. For the complete list of
162 diagnostic messages, see L<perldiag>.
164 XXX New or changed warnings emitted by the core's C<C> code go here. Also
165 include any changes in L<perldiag> that reconcile it to the C<C> code.
167 [ Within each section, list entries as a =item entry that links to perldiag,
172 L<Invalid version object|perldiag/"Invalid version object">
175 =head2 New Diagnostics
177 XXX Newly added diagnostic messages go here
185 L<Group name must start with a non-digit word character in regex; marked by <-- HERE in m/%s/|perldiag/"Group name must start with a non-digit word character in regex; marked by <-- HERE in m/%s/">
187 This error has been added for C<(?&0)>, which is invalid. It used to
188 produce an incomprehensible error message [perl #101666].
198 C<chr()> now warns when passed a negative value [perl #83048].
202 C<srand()> now warns when passed a value that doesn't fit in a C<UV> (since the
203 value will be truncated rather than overflowing) [perl #40605].
207 =head2 Changes to Existing Diagnostics
209 XXX Changes (i.e. rewording) of diagnostic messages go here
215 XXX Describe change here
219 =head1 Utility Changes
221 XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go
222 here. Most of these are built within the directories F<utils> and F<x2p>.
224 [ List utility changes as a =head3 entry for each utility and =item
225 entries for each change
226 Use L<XXX> with program names to get proper documentation linking. ]
238 =head1 Configuration and Compilation
240 XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
241 go here. Any other changes to the Perl build process should be listed here.
242 However, any platform-specific changes should be listed in the
243 L</Platform Support> section, instead.
245 [ List changes as a =item entry ].
251 Building perl with some Windows compilers used to fail due to a problem
252 with miniperl's C<glob> operator (which uses the C<perlglob> program)
253 deleting the PATH environment variable [perl #113798].
257 C<delete local> no longer crashes with certain magical arrays and hashes
262 C<local> on elements of certain magical arrays and hashes used not to
263 arrange to have the element deleted on scope exit, even if the element did
264 not exist before C<local>.
270 XXX Any significant changes to the testing of a freshly built perl should be
271 listed here. Changes which create B<new> files in F<t/> go here as do any
272 large changes to the testing harness (e.g. when parallel testing was added).
273 Changes to existing files in F<t/> aren't worth summarising, although the bugs
274 that they represent may be covered elsewhere.
276 [ List each test improvement as a =item entry ]
286 =head1 Platform Support
288 XXX Any changes to platform support should be listed in the sections below.
290 [ Within the sections, list each platform as a =item entry with specific
291 changes as paragraphs below it. ]
295 XXX List any platforms that this version of perl compiles on, that previous
296 versions did not. These will either be enabled by new files in the F<hints/>
297 directories, or new subdirectories and F<README> files at the top level of the
302 =item XXX-some-platform
308 =head2 Discontinued Platforms
310 XXX List any platforms that this version of perl no longer compiles on.
314 =item XXX-some-platform
320 =head2 Platform-Specific Notes
322 XXX List any changes for specific platforms. This could include configuration
323 and compilation changes or changes in portability/compatibility. However,
324 changes within modules for platforms should generally be listed in the
325 L</Modules and Pragmata> section.
329 =item XXX-some-platform
335 =head1 Internal Changes
337 XXX Changes which affect the interface available to C<XS> code go here.
338 Other significant internal changes for future core maintainers should
341 [ List each change as a =item entry ]
351 =head1 Selected Bug Fixes
353 XXX Important bug fixes in the core language are summarised here.
354 Bug fixes in files in F<ext/> and F<lib/> are best summarised in
355 L</Modules and Pragmata>.
357 [ List each fix as a =item entry ]
363 A regression introduced in v5.14.0 has been fixed, in which some calls
364 to the C<re> module would clobber C<$_>.
368 C<do FILE> now always either sets or clears C<$@>, even when the file can't be
369 read. This ensures that testing C<$@> first (as recommended by the
370 documentation) always returns the correct result.
374 The array iterator used for the C<each @array> construct is now correctly
375 reset when C<@array> is cleared (RT #75596). This happens for example when the
376 array is globally assigned to, as in C<@array = (...)>, but not when its
377 B<values> are assigned to. In terms of the XS API, it means that C<av_clear()>
378 will now reset the iterator.
380 This mirrors the behaviour of the hash iterator when the hash is cleared.
384 C<< $class->can >>, C<< $class->isa >>, and C<< $class->DOES >> now return
385 correct results, regardless of whether that package referred to by C<$class>
386 exists [perl #47113].
390 Arriving signals no longer clear C<$@> [perl #45173].
394 Allow C<my ()> declarations with an empty variable list [perl #113554].
398 During parsing, subs declared after errors no longer leave stubs
403 Closures containing no string evals no longer hang on to their containing
404 subroutines, allowing variables closed over by outer subroutines to be
405 freed when the outer sub is freed, even if the inner sub still exists
410 Duplication of in-memory filehandles by opening with a "<&=" or ">&=" mode
411 stopped working properly in 5.16.0. It was causing the new handle to
412 reference a different scalar variable. This has been fixed [perl #113764].
416 C<qr//> expressions no longer crash with custom regular expression engines
417 that do not set C<offs> at regular expression compilation time
422 =head1 Known Problems
424 XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
425 tests that had to be C<TODO>ed for the release would be noted here. Unfixed
426 platform specific bugs also go here.
428 [ List each fix as a =item entry ]
440 XXX If any significant core contributor has died, we've added a short obituary
443 =head1 Acknowledgements
445 XXX Generate this with:
447 perl Porting/acknowledgements.pl v5.17.1..HEAD
449 =head1 Reporting Bugs
451 If you find what you think is a bug, you might check the articles
452 recently posted to the comp.lang.perl.misc newsgroup and the perl
453 bug database at http://rt.perl.org/perlbug/ . There may also be
454 information at http://www.perl.org/ , the Perl Home Page.
456 If you believe you have an unreported bug, please run the L<perlbug>
457 program included with your release. Be sure to trim your bug down
458 to a tiny but sufficient test case. Your bug report, along with the
459 output of C<perl -V>, will be sent off to perlbug@perl.org to be
460 analysed by the Perl porting team.
462 If the bug you are reporting has security implications, which make it
463 inappropriate to send to a publicly archived mailing list, then please send
464 it to perl5-security-report@perl.org. This points to a closed subscription
465 unarchived mailing list, which includes
466 all the core committers, who will be able
467 to help assess the impact of issues, figure out a resolution, and help
468 co-ordinate the release of patches to mitigate or fix the problem across all
469 platforms on which Perl is supported. Please only use this address for
470 security issues in the Perl core, not for modules independently
475 The F<Changes> file for an explanation of how to view exhaustive details
478 The F<INSTALL> file for how to build Perl.
480 The F<README> file for general stuff.
482 The F<Artistic> and F<Copying> files for copyright information.