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 v5.15.1
12 This document describes differences between the 5.15.1 release and
15 If you are upgrading from an earlier release such as 5.14.0, first read
16 L<perl5150delta>, which describes differences between 5.14.0 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 ]
31 =head2 C<splice()> doesn't warn when truncating
33 You can now limit the size of an array using C<splice(@a,MAX_LEN)> without
34 worrying about warnings.
36 =head2 The C<\$> prototype accepts any scalar lvalue
38 The C<\$> and C<\[$]> subroutine prototypes now accept any scalar lvalue
39 argument. Previously they only accepted scalars beginning with C<$> and
40 hash and array elements. This change makes them consistent with the way
41 the built-in C<read> and C<recv> functions (among others) parse their
42 arguments. This means that one can override the built-in functions with
43 custom subroutines that parse their arguments the same way.
47 XXX Any security-related notices go here. In particular, any security
48 vulnerabilities closed should be noted here rather than in the
49 L</Selected Bug Fixes> section.
51 [ List each security issue as a =head2 entry ]
53 =head1 Incompatible Changes
55 XXX For a release on a stable branch, this section aspires to be:
57 There are no changes intentionally incompatible with 5.XXX.XXX
58 If any exist, they are bugs and reports are welcome.
60 [ List each incompatible change as a =head2 entry ]
64 XXX Any deprecated features, syntax, modules etc. should be listed here.
65 In particular, deprecated modules should be listed here even if they are
66 listed as an updated module in the L</Modules and Pragmata> section.
68 [ List each deprecation as a =head2 entry ]
70 =head1 Performance Enhancements
72 XXX Changes which enhance performance without changing behaviour go here. There
73 may well be none in a stable release.
75 [ List each enhancement as a =item entry ]
81 The implementation of C<s///r> makes one fewer copy of the scalar's value.
85 If a studied scalar is C<split> with a regex, the engine will now take
86 advantage of the C<study> data.
90 =head1 Modules and Pragmata
92 XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
93 go here. If Module::CoreList is updated, generate an initial draft of the
94 following sections using F<Porting/corelist-perldelta.pl>, which prints stub
95 entries to STDOUT. Results can be pasted in place of the '=head2' entries
96 below. A paragraph summary for important changes should then be added by hand.
97 In an ideal world, dual-life modules would have a F<Changes> file that could be
100 [ Within each section, list entries as a =item entry ]
102 =head2 New Modules and Pragmata
112 =head2 Updated Modules and Pragmata
118 L<Compress::Raw::Bzip2> has been upgraded from version 2.035 to version 2.037
122 L<Compress::Raw::Zlib> has been upgraded from version 2.035 to version 2.037
124 Added offset parameter to CRC32
128 L<Compress::Zlib> has been upgraded from version 2.035 to version 2.037
130 IO::Compress::Zip and IO::Uncompress::Unzip now have support for LZMA (method 14).
131 There is a fix for a CRC issue in IO::Compress::Unzip and it supports Streamed
132 Stored context now. And fixed a Zip64 issue in
133 IO::Compress::Zip when the content size was exactly 0xFFFFFFFF.
137 L<IPC::Cmd> has been upgraded from version 0.70 to version 0.72
139 Capturing of command output (both C<STDOUT> and C<STDERR>) is now supported
140 using L<IPC::Open3> on MSWin32 without requiring L<IPC::Run>.
144 L<attributes> has been upgraded from version 0.14 to 0.15, as part of the
145 lvalue attribute warnings fix. See L</Selected Bug Fixes>, below.
149 L<Math::BigInt::FastCalc> has been upgraded from version 0.28 to version 0.29.
151 The XS code is now compiled with C<PERL_NO_GET_CONTEXT>, which will aid
152 performance under ithreads.
156 =head2 Removed Modules and Pragmata
168 XXX Changes to files in F<pod/> go here. Consider grouping entries by
169 file and be sure to link to the appropriate page, e.g. L<perlfunc>.
171 =head2 New Documentation
173 XXX Changes which create B<new> files in F<pod/> go here.
177 XXX Description of the purpose of the new file here
179 =head2 Changes to Existing Documentation
181 XXX Changes which significantly change existing files in F<pod/> go here.
182 However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
191 XXX Description of the change here
197 The following additions or changes have been made to diagnostic output,
198 including warnings and fatal error messages. For the complete list of
199 diagnostic messages, see L<perldiag>.
201 XXX New or changed warnings emitted by the core's C<C> code go here. Also
202 include any changes in L<perldiag> that reconcile it to the C<C> code.
204 [ Within each section, list entries as a =item entry that links to perldiag,
209 L<Invalid version object|perldiag/"Invalid version object">
212 =head2 New Diagnostics
214 XXX Newly added diagnostic messages go here
222 XXX L<message|perldiag/"message">
232 XXX L<message|perldiag/"message">
236 =head2 Changes to Existing Diagnostics
238 XXX Changes (i.e. rewording) of diagnostic messages go here
244 XXX Describe change here
248 =head1 Utility Changes
250 XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go
251 here. Most of these are built within the directories F<utils> and F<x2p>.
253 [ List utility changes as a =head3 entry for each utility and =item
254 entries for each change
255 Use L<XXX> with program names to get proper documentation linking. ]
267 =head1 Configuration and Compilation
269 XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
270 go here. Any other changes to the Perl build process should be listed here.
271 However, any platform-specific changes should be listed in the
272 L</Platform Support> section, instead.
274 [ List changes as a =item entry ].
286 XXX Any significant changes to the testing of a freshly built perl should be
287 listed here. Changes which create B<new> files in F<t/> go here as do any
288 large changes to the testing harness (e.g. when parallel testing was added).
289 Changes to existing files in F<t/> aren't worth summarising, although the bugs
290 that they represent may be covered elsewhere.
292 [ List each test improvement as a =item entry ]
302 =head1 Platform Support
304 XXX Any changes to platform support should be listed in the sections below.
306 [ Within the sections, list each platform as a =item entry with specific
307 changes as paragraphs below it. ]
311 XXX List any platforms that this version of perl compiles on, that previous
312 versions did not. These will either be enabled by new files in the F<hints/>
313 directories, or new subdirectories and F<README> files at the top level of the
318 =item XXX-some-platform
324 =head2 Discontinued Platforms
326 XXX List any platforms that this version of perl no longer compiles on.
330 =item XXX-some-platform
336 =head2 Platform-Specific Notes
338 XXX List any changes for specific platforms. This could include configuration
339 and compilation changes or changes in portability/compatibility. However,
340 changes within modules for platforms should generally be listed in the
341 L</Modules and Pragmata> section.
345 =item XXX-some-platform
351 =head1 Internal Changes
353 XXX Changes which affect the interface available to C<XS> code go here.
354 Other significant internal changes for future core maintainers should
357 [ List each change as a =item entry ]
367 =head1 Selected Bug Fixes
369 XXX Important bug fixes in the core language are summarised here.
370 Bug fixes in files in F<ext/> and F<lib/> are best summarised in
371 L</Modules and Pragmata>.
373 [ List each fix as a =item entry ]
379 Applying the :lvalue attribute to subroutine that is already defined does
380 not work properly, as the attribute changes the way the sub is compiled.
381 Hence, Perl 5.12 began warning when an attempt is made to apply the
382 attribute to an already defined sub. In such cases, the attribute is
385 But the change in 5.12 missed the case where custom attributes are also
386 present: that case still silently and ineffectively applied the attribute.
387 That omission has now been corrected. C<sub foo :lvalue :Whatever> (when
388 C<foo> is already defined) now warns about the :lvalue attribute, and does
391 L<attributes.pm|attributes> has likewise been updated to warn and not apply
397 Not necessary for perl5160delta
399 The remaining discrepancies between explicit and implicit return from
400 lvalue subroutines have been resolved. They mainly involved which error
401 message to display when a read-only value is returned in lvalue context.
402 Also, returning a PADTMP (the result of most built-ins, like C<index>) in
403 lvalue context is now forbidden for explicit return, as it always has been
404 for implicit return. This is not a regression from 5.14, as all the cases
405 in which it could happen where previously syntax errors.
410 Not necessary for perl5160delta
412 Explicitly returning a tied C<my> variable from an lvalue subroutine in
413 list lvalue context used to clear the variable before the assignment could
414 happen. This is something that was missed when explicit return was made to
420 Not necessary for perl5160delta
422 A minor memory leak, introduced in 5.15.0, has been fixed. It would occur
423 when a hash is freed that has had its current iterator deleted
428 =head1 Known Problems
430 XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
431 tests that had to be C<TODO>ed for the release would be noted here, unless
432 they were specific to a particular platform (see below).
434 This is a list of some significant unfixed bugs, which are regressions
435 from either 5.XXX.XXX or 5.XXX.XXX.
437 [ List each fix as a =item entry ]
449 XXX If any significant core contributor has died, we've added a short obituary
452 =head1 Acknowledgements
454 XXX The list of people to thank goes here.
456 =head1 Reporting Bugs
458 If you find what you think is a bug, you might check the articles
459 recently posted to the comp.lang.perl.misc newsgroup and the perl
460 bug database at http://rt.perl.org/perlbug/ . There may also be
461 information at http://www.perl.org/ , the Perl Home Page.
463 If you believe you have an unreported bug, please run the L<perlbug>
464 program included with your release. Be sure to trim your bug down
465 to a tiny but sufficient test case. Your bug report, along with the
466 output of C<perl -V>, will be sent off to perlbug@perl.org to be
467 analysed by the Perl porting team.
469 If the bug you are reporting has security implications, which make it
470 inappropriate to send to a publicly archived mailing list, then please send
471 it to perl5-security-report@perl.org. This points to a closed subscription
472 unarchived mailing list, which includes
473 all the core committers, who will be able
474 to help assess the impact of issues, figure out a resolution, and help
475 co-ordinate the release of patches to mitigate or fix the problem across all
476 platforms on which Perl is supported. Please only use this address for
477 security issues in the Perl core, not for modules independently
482 The F<Changes> file for an explanation of how to view exhaustive details
485 The F<INSTALL> file for how to build Perl.
487 The F<README> file for general stuff.
489 The F<Artistic> and F<Copying> files for copyright information.