4 This has been completed up to 527d644b124fe.
8 [ this is a template for a new perldelta file. Any text flagged as
9 XXX needs to be processed before release. ]
11 perldelta - what is new for perl v5.15.3
15 This document describes differences between the 5.15.2 release and
18 If you are upgrading from an earlier release such as 5.15.1, first read
19 L<perl5152delta>, which describes differences between 5.15.1 and
24 XXX Any important notices here
26 =head1 Core Enhancements
28 XXX New core language features go here. Summarise user-visible core language
29 enhancements. Particularly prominent performance optimisations could go
30 here, but most should go in the L</Performance Enhancements> section.
32 [ List each enhancement as a =head2 entry ]
34 =head2 More CORE subs are callable through references
36 Perl 5.15., introduced subroutines in the CORE namespace. Most of them
37 could only be called as barewords; i.e., they could be aliased at compile
38 time and then inlined under new names.
40 Many more of these functions can now be called through references and via
41 C<&foo()> syntax, bypassing the prototype.
43 XXX This is too vague, but the exact list of them will likely change before
44 5.15.3. It's currently functions whose prototypes match /^[\$_]+;?\z/.
48 XXX Any security-related notices go here. In particular, any security
49 vulnerabilities closed should be noted here rather than in the
50 L</Selected Bug Fixes> section.
52 [ List each security issue as a =head2 entry ]
54 =head1 Incompatible Changes
56 =head2 User-defined case changing operations.
58 This feature was deprecated in Perl 5.14, and has now been removed.
59 The CPAN module L<Unicode::Casing> provides better functionality without
60 the drawbacks that this feature had, as are detailed in the 5.14
62 L<http://perldoc.perl.org/5.14.0/perlunicode.html#User-Defined-Case-Mappings-%28for-serious-hackers-only%29>
64 =head2 XSUBs are now 'static'
66 XSUB C functions are now 'static', that is, they are not visible from
67 outside the compilation unit. For the exceedingly rare case where
68 this is not desired, a new public macro C<XS_EXTERNAL(name)> can be
69 used in place of C<XS(name)>. C<ExtUtils::ParseXS> (C<xsubpp>)
70 can be made to declare XSUBs with C<XS_EXTERNAL> using the
71 C<EXPORT_XSUB_SYMBOLS> keyword, see L<perlxs> for details.
75 XXX Any deprecated features, syntax, modules etc. should be listed here.
76 In particular, deprecated modules should be listed here even if they are
77 listed as an updated module in the L</Modules and Pragmata> section.
79 [ List each deprecation as a =head2 entry ]
81 =head1 Performance Enhancements
83 XXX Changes which enhance performance without changing behaviour go here. There
84 may well be none in a stable release.
86 [ List each enhancement as a =item entry ]
96 =head1 Modules and Pragmata
98 XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
99 go here. If Module::CoreList is updated, generate an initial draft of the
100 following sections using F<Porting/corelist-perldelta.pl>, which prints stub
101 entries to STDOUT. Results can be pasted in place of the '=head2' entries
102 below. A paragraph summary for important changes should then be added by hand.
103 In an ideal world, dual-life modules would have a F<Changes> file that could be
106 [ Within each section, list entries as a =item entry ]
108 =head2 New Modules and Pragmata
118 =head2 Updated Modules and Pragmata
124 L<Archive::Extract> has been upgraded from version 0.52 to version 0.56
126 Resolved an issue where C<unzip> executable was present in C<PATH> on MSWin32
130 L<diagnostics> has been upgraded from version 1.24 to 1.25.
132 It now strips out C<SZ<><...>> formatting codes before displaying
133 descriptions [perl #94488].
137 L<Math::BigRat> has been upgraded from version 0.2602 to 0.2603.
139 C<int()> on a Math::BigRat object containing -1/2 now creates a
140 Math::BigInt containing 0, rather than -0. L<Math::BigInt> does not even
141 support negative zero, so the resulting object was actually malformed
146 L<Pod::Simple> has been upgraded from version 3.18 to 3.19.
150 =head2 Removed Modules and Pragmata
162 XXX Changes to files in F<pod/> go here. Consider grouping entries by
163 file and be sure to link to the appropriate page, e.g. L<perlfunc>.
165 =head2 New Documentation
167 XXX Changes which create B<new> files in F<pod/> go here.
171 XXX Description of the purpose of the new file here
173 =head2 Changes to Existing Documentation
175 XXX Changes which significantly change existing files in F<pod/> go here.
176 However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
185 XXX Description of the change here
191 The following additions or changes have been made to diagnostic output,
192 including warnings and fatal error messages. For the complete list of
193 diagnostic messages, see L<perldiag>.
195 XXX New or changed warnings emitted by the core's C<C> code go here. Also
196 include any changes in L<perldiag> that reconcile it to the C<C> code.
198 [ Within each section, list entries as a =item entry that links to perldiag,
203 L<Invalid version object|perldiag/"Invalid version object">
206 =head2 New Diagnostics
208 XXX Newly added diagnostic messages go here
216 XXX L<message|perldiag/"message">
226 XXX L<message|perldiag/"message">
230 =head2 Changes to Existing Diagnostics
232 XXX Changes (i.e. rewording) of diagnostic messages go here
238 XXX Describe change here
242 =head1 Utility Changes
244 XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go
245 here. Most of these are built within the directories F<utils> and F<x2p>.
247 [ List utility changes as a =head3 entry for each utility and =item
248 entries for each change
249 Use L<XXX> with program names to get proper documentation linking. ]
261 =head1 Configuration and Compilation
263 XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
264 go here. Any other changes to the Perl build process should be listed here.
265 However, any platform-specific changes should be listed in the
266 L</Platform Support> section, instead.
268 [ List changes as a =item entry ].
274 The file F<global.sym> is no longer needed, and has been removed. It
275 contained a list of all exported functions, one of the files generated by
276 F<regen/embed.pl> from data in F<embed.fnc> and F<regen/opcodes>. The code
277 has been refactored so that the only user of F<global.sym>, F<makedef.pl>,
278 now reads F<embed.fnc> and F<regen/opcodes> directly, removing the need to
279 store the list of exported functions in an intermediate file.
281 As F<global.sym> was never installed, this change will not be visible
282 outside the build process.
288 XXX Any significant changes to the testing of a freshly built perl should be
289 listed here. Changes which create B<new> files in F<t/> go here as do any
290 large changes to the testing harness (e.g. when parallel testing was added).
291 Changes to existing files in F<t/> aren't worth summarising, although the bugs
292 that they represent may be covered elsewhere.
294 [ List each test improvement as a =item entry ]
300 F<t/porting/globvar.t> has been added, to run a sanity check on F<globar.sym>.
301 F<globar.sym> is not needed on most *nix platforms, but is for Win32, hence
302 previously was it was possible to inadvertently commit changes that worked
303 perfectly locally, but broke the build on Win32.
307 F<t/op/unlink.t> has been added to test the C<unlink> function.
311 =head1 Platform Support
313 XXX Any changes to platform support should be listed in the sections below.
315 [ Within the sections, list each platform as a =item entry with specific
316 changes as paragraphs below it. ]
320 XXX List any platforms that this version of perl compiles on, that previous
321 versions did not. These will either be enabled by new files in the F<hints/>
322 directories, or new subdirectories and F<README> files at the top level of the
327 =item XXX-some-platform
333 =head2 Discontinued Platforms
335 XXX List any platforms that this version of perl no longer compiles on.
339 =item XXX-some-platform
345 =head2 Platform-Specific Notes
347 XXX List any changes for specific platforms. This could include configuration
348 and compilation changes or changes in portability/compatibility. However,
349 changes within modules for platforms should generally be listed in the
350 L</Modules and Pragmata> section.
354 =item XXX-some-platform
360 =head1 Internal Changes
362 XXX Changes which affect the interface available to C<XS> code go here.
363 Other significant internal changes for future core maintainers should
366 [ List each change as a =item entry ]
376 =head1 Selected Bug Fixes
378 XXX Important bug fixes in the core language are summarised here.
379 Bug fixes in files in F<ext/> and F<lib/> are best summarised in
380 L</Modules and Pragmata>.
382 [ List each fix as a =item entry ]
388 In Perl 5.15.0 C<defined(${'$'})> stopped returning true if the C<$$>
389 variable had not been used yet. This has been fixed.
393 Perl 5.10.0 introduced a similar bug: C<defined(*{"foo"})> where "foo"
394 represents the name of a built-in global variable used to return false if
395 the variable had never been used before, but only on the I<first> call.
396 This, too, has been fixed.
400 Various functions that take a filehandle argument in rvalue context
401 (C<close>, C<readline>, etc.) used to call C<FETCH> multiple times, if it
402 was a tied variable, and warn twice, if it was C<undef> [perl #97482].
406 C<close> and similar filehandle functions, when called on built-in global
407 variables (like C<$+>), used to die if the variable happened to hold the
408 undefined value, instead of producing the usual "Use of uninitialized
413 When autovivified file handles were introduced in Perl 5.6.0, C<readline>
414 was inadvertently made to autovivify when called as C<readline($foo)> (but
415 not as C<< <$foo> >>). It has now been fixed never to autovivify.
419 C<defined ${ $tied_variable }> used to call C<FETCH> multiple times, but
420 now calls it just once.
424 Some cases of dereferencing a complex expression, such as
425 C<${ (), $tied } = 1>, used to call C<FETCH> multiple times, but now call
430 For a tied variable returning a package name, C<< $tied->method >> used to
431 call C<FETCH> multiple times (even up to six!), and sometimes would
432 fail to call the method, due to memory corruption.
436 Calling an undefined anonymous subroutine (e.g., what $x holds after
437 C<undef &{$x = sub{}}>) used to cause a "Not a CODE reference" error, which
438 has been corrected to "Undefined subroutine called" [perl #71154].
442 Causing C<@DB::args> to be freed between uses of C<caller> no longer
443 results in a crash [perl #93320].
447 Since 5.6.0, C<*{ ... }> has been inconsistent in how it treats undefined
448 values. It would die in strict mode or lvalue context for most undefined
449 values, but would be treated as the empty string (with a warning) for the
450 specific scalar return by C<undef()> (C<&PL_sv_undef> internally). This
451 has been corrected. C<undef()> is now treated like other undefined
452 scalars, as in Perl 5.005.
456 It used to be possible to free the typeglob of a localised array or hash
457 (e.g., C<local @{"x"}; delete $::{x}>), resulting in a crash on scope exit.
461 C<setpgrp($foo)> used to be equivalent to C<($foo, setpgrp)>, because
462 C<setpgrp> was ignoring its argument if there was just one. Now it is
463 equivalent to C<setpgrp($foo,0)>.
467 =head1 Known Problems
469 XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
470 tests that had to be C<TODO>ed for the release would be noted here, unless
471 they were specific to a particular platform (see below).
473 This is a list of some significant unfixed bugs, which are regressions
474 from either 5.XXX.XXX or 5.XXX.XXX.
476 [ List each fix as a =item entry ]
488 XXX If any significant core contributor has died, we've added a short obituary
491 =head1 Acknowledgements
493 XXX Generate this with:
495 perl Porting/acknowledgements.pl v5.15.2..HEAD
497 =head1 Reporting Bugs
499 If you find what you think is a bug, you might check the articles
500 recently posted to the comp.lang.perl.misc newsgroup and the perl
501 bug database at http://rt.perl.org/perlbug/ . There may also be
502 information at http://www.perl.org/ , the Perl Home Page.
504 If you believe you have an unreported bug, please run the L<perlbug>
505 program included with your release. Be sure to trim your bug down
506 to a tiny but sufficient test case. Your bug report, along with the
507 output of C<perl -V>, will be sent off to perlbug@perl.org to be
508 analysed by the Perl porting team.
510 If the bug you are reporting has security implications, which make it
511 inappropriate to send to a publicly archived mailing list, then please send
512 it to perl5-security-report@perl.org. This points to a closed subscription
513 unarchived mailing list, which includes
514 all the core committers, who will be able
515 to help assess the impact of issues, figure out a resolution, and help
516 co-ordinate the release of patches to mitigate or fix the problem across all
517 platforms on which Perl is supported. Please only use this address for
518 security issues in the Perl core, not for modules independently
523 The F<Changes> file for an explanation of how to view exhaustive details
526 The F<INSTALL> file for how to build Perl.
528 The F<README> file for general stuff.
530 The F<Artistic> and F<Copying> files for copyright information.