4 * changelogged up to 45a6a02
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 v5.13.5
15 This document describes differences between the 5.13.4 release and
18 If you are upgrading from an earlier release such as 5.13.3, first read
19 L<perl5134delta>, which describes differences between 5.13.3 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 =head2 Adjacent pairs of nextstate opcodes are now optimized away
34 Previously, in code such as
36 use constant DEBUG => 0;
43 the ops for C<warn if DEBUG;> would be folded to a C<null> op (C<ex-const>), but
44 the C<nextstate> op would remain, resulting in a runtime op dispatch of
45 C<nextstate>, C<nextstate>, ...
47 The execution of a sequence of C<nexstate> ops is indistinguishable from just
48 the last C<nextstate> op, so teach the peephole optimiser to eliminate the first
49 of a pair of C<nextstate> ops. (Except where the first carries a label, as
50 labels mustn't be eliminated by the optimiser, and label usage isn't
51 conclusively known at compile time.)
53 =head2 API function to parse statements
55 The C<parse_fullstmt> function has been added to allow parsing of a single
56 complete Perl statement. See L<perlapi> for details.
58 =head2 API functions for accessing the runtime hinthash
60 A new C API for introspecting the hinthash C<%^H> at runtime has been added. See
61 C<cop_hints_2hv>, C<cop_hints_fetchpvn>, C<cop_hints_fetchpvs>,
62 C<cop_hints_fetchsv>, and C<hv_copy_hints_hv> in L<perlapi> for details.
64 =head2 C interface to C<caller()>
66 The C<caller_cx> function has been added as an XSUB-writer's equivalent of
67 C<caller()>. See L<perlapi> for details.
71 XXX Any security-related notices go here. In particular, any security
72 vulnerabilities closed should be noted here rather than in the
73 L</Selected Bug Fixes> section.
75 [ List each security issue as a =head2 entry ]
77 =head1 Incompatible Changes
79 =head2 Magic Variables Outside the Main Package
81 In previous versions of perl, magic variables like C<$!>, C<%SIG>, etc. would
82 'leak' into other packages. So C<%foo::SIG> could be used to access signals,
83 C<${"foo::!"}> (with strict mode off) to access C's C<errno>, etc.
85 This was a bug, or an 'unintentional' feature, which caused various ill
86 effects, such as signal handlers being wiped when modules were loaded, etc.
88 This has been fixed (or the feature has been removed, depending on how you
91 =head2 Smart-matching against array slices
93 Previously, the following code resulted in a successful match:
99 This odd behaviour has now been fixed [perl #77468].
103 The first argument of the C API function C<Perl_fetch_cop_label> has changed
104 from C<struct refcounted he *> to C<COP *>, to better insulate the user from
105 implementation details.
107 This API function was marked as "may change", and likely isn't in use outside
108 the core. (Neither an unpacked CPAN, nor Google's codesearch, finds any other
113 XXX Any deprecated features, syntax, modules etc. should be listed here.
114 In particular, deprecated modules should be listed here even if they are
115 listed as an updated module in the L</Modules and Pragmata> section.
117 =head2 Use of qw(...) as parentheses
119 Historically the parser fooled itself into thinking that C<qw(...)> literals
120 were always enclosed in parentheses, and as a result you could sometimes omit
121 parentheses around them:
123 for $x qw(a b c) { ... }
125 The parser no longer lies to itself in this way. Wrap the list literal in
128 for $x (qw(a b c)) { ... }
130 =head1 Performance Enhancements
132 XXX Changes which enhance performance without changing behaviour go here. There
133 may well be none in a stable release.
135 [ List each enhancement as a =item entry ]
141 Scalars containing regular expressions now only allocate the part of the C<SV>
142 body they actually use, saving some space.
146 Compiling regular expressions has been made faster for the case where upgrading
147 the regex to utf8 is necessary, but that isn't known when the compilation
152 =head1 Modules and Pragmata
154 XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
155 go here. If Module::CoreList is updated, generate an initial draft of the
156 following sections using F<Porting/corelist-perldelta.pl>, which prints stub
157 entries to STDOUT. Results can be pasted in place of the '=head2' entries
158 below. A paragraph summary for important changes should then be added by hand.
159 In an ideal world, dual-life modules would have a F<Changes> file that could be
162 [ Within each section, list entries as a =item entry ]
164 =head2 New Modules and Pragmata
174 =head2 Updated Modules and Pragmata
180 C<blib> has been upgraded from version 1.05 to 1.06.
184 C<bignum>, C<bigint>, and C<bigrat> have been upgraded from version 0.23 to
189 C<open> has been upgraded from version 1.07 to 1.08.
193 C<warnings> has been upgraded from version 1.10 to 1.11.
195 C<warnings::register> has been upgraded from version 1.01 to 1.02.
197 It is now possible to register warning categories other than the names of
198 packages using warnings::register. See L<perllexwarn> for more information.
202 C<B::Debug> has been upgraded from version 1.12 to 1.16.
206 C<Data::Dumper> has been upgraded from version 2.126 to 2.128.
208 This fixes a crash when using custom sort functions that might cause the stack
213 C<Encode> has been upgraded from version 2.39 to 2.40.
217 C<Errno> has been upgraded from version 1.12 to 1.13.
219 On some platforms with unusual header files, like Win32/gcc using mingw64
220 headers, some constants which weren't actually error numbers have been exposed
221 by C<Errno>. This has been fixed (RT#77416).
225 C<ExtUtils::MakeMaker> has been upgraded from version 6.56 to 6.57_05.
229 C<Filter::Simple> has been upgraded from version 0.84 to 0.85.
233 C<Hash::Util> has been upgraded from version 0.08 to 0.09.
237 C<Math::BigInt> has been upgraded from version 1.89_01 to 1.95.
238 C<Math::BigInt::Calc> has been upgraded from version 0.52 to 0.54.
240 This fixes, among other things, incorrect results when computing binomial
241 coefficients (RT#77640).
245 C<Math::BigInt::FastCalc> has been upgraded from version 0.19 to 0.22.
249 C<Math::BigRat> has been upgraded from version 0.24 to 0.26.
253 C<Module::CoreList> has been upgraded from version 2.37 to 2.38.
257 C<POSIX> has been upgraded from version 1.19 to 1.20.
259 It now includes constants for POSIX signal constants.
263 C<Safe> has been upgraded from version 2.27 to 2.28.
265 This fixes a possible infinite loop when looking for coderefs.
269 C<Tie::Hash> has been upgraded from version 1.03 to 1.04.
271 Calling C<< Tie::Hash->TIEHASH() >> used to loop forever. Now it C<croak>s.
275 C<Unicode::Collate> has been upgraded from version 0.56 to 0.59.
279 C<XSLoader> has been upgraded from version 0.10 to 0.11.
283 =head2 Removed Modules and Pragmata
295 XXX Changes to files in F<pod/> go here. Consider grouping entries by
296 file and be sure to link to the appropriate page, e.g. L<perlfunc>.
298 =head2 New Documentation
300 XXX Changes which create B<new> files in F<pod/> go here.
304 XXX Description of the purpose of the new file here
306 =head2 Changes to Existing Documentation
308 XXX Changes which significantly change existing files in F<pod/> go here.
309 However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
318 Many of the optree construction functions are now documented.
324 L<perlfaq>, L<perlfaq2>, L<perlfaq4>, L<perlfaq5>, L<perlfaq6>, L<perlfaq8>, and
325 L<perlfaq9> have seen various updates and modernisations.
329 The following additions or changes have been made to diagnostic output,
330 including warnings and fatal error messages. For the complete list of
331 diagnostic messages, see L<perldiag>.
333 XXX New or changed warnings emitted by the core's C<C> code go here. Also
334 include any changes in L<perldiag> that reconcile it to the C<C> code.
336 [ Within each section, list entries as a =item entry ]
338 =head2 New Diagnostics
340 XXX Newly added diagnostic messages go here
346 Use of qw(...) as parentheses is deprecated
350 =head2 Changes to Existing Diagnostics
352 XXX Changes (i.e. rewording) of diagnostic messages go here
362 =head1 Utility Changes
364 XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go
365 here. Most of these are built within the directories F<utils> and F<x2p>.
367 [ List utility changes as a =head3 entry for each utility and =item
368 entries for each change
369 Use L<XXX> with program names to get proper documentation linking. ]
377 The use of a deprecated C<goto> construct has been removed (RT#74404).
381 =head1 Configuration and Compilation
383 XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
384 go here. Any other changes to the Perl build process should be listed here.
385 However, any platform-specific changes should be listed in the
386 L</Platform Support> section, instead.
388 [ List changes as a =item entry ].
400 XXX Any significant changes to the testing of a freshly built perl should be
401 listed here. Changes which create B<new> files in F<t/> go here as do any
402 large changes to the testing harness (e.g. when parallel testing was added).
403 Changes to existing files in F<t/> aren't worth summarising, although the bugs
404 that they represent may be covered elsewhere.
406 [ List each test improvement as a =item entry ]
412 A rare race condition in F<t/op/while_readdir.t> has been fixed, stopping it
413 from failing randomly when running tests in parallel.
417 The new F<t/op/leaky-magic.t> script tests that magic applied to variables in
418 the main packages does not affect other packages.
422 =head1 Platform Support
424 XXX Any changes to platform support should be listed in the sections below.
426 [ Within the sections, list each platform as a =item entry with specific
427 changes as paragraphs below it. ]
431 XXX List any platforms that this version of perl compiles on, that previous
432 versions did not. These will either be enabled by new files in the F<hints/>
433 directories, or new subdirectories and F<README> files at the top level of the
438 =item XXX-some-platform
444 =head2 Discontinued Platforms
446 XXX List any platforms that this version of perl no longer compiles on.
450 =item XXX-some-platform
456 =head2 Platform-Specific Notes
458 XXX List any changes for specific platforms. This could include configuration
459 and compilation changes or changes in portability/compatibility. However,
460 changes within modules for platforms should generally be listed in the
461 L</Modules and Pragmata> section.
471 Make PerlIOUnix_open honor default permissions on VMS.
473 When perlio became the default and unixio became the default bottom layer, the
474 most common path for creating files from Perl became C<PerlIOUnix_open>, which
475 has always explicitly used C<0666> as the permission mask.
477 To avoid this, C<0777> is now passed as the permissions to C<open()>. In the VMS
478 CRTL, C<0777> has a special meaning over and above intersecting with the current
479 umask; specifically, it allows Unix syscalls to preserve native default
486 =head1 Internal Changes
488 XXX Changes which affect the interface available to C<XS> code go here.
489 Other significant internal changes for future core maintainers should
492 [ List each test improvement as a =item entry ]
498 C<CALL_FPTR> and C<CPERLscope> have been removed deprecated.
500 Those are left from an old implementation of C<MULTIPLICITY> using C++ objects,
501 which has been removed in 5.8. Nowadays these macros do exactly nothing, so they
502 shouldn't be used anymore.
504 For compatibility, they are still defined for external C<XS> code. Only
505 extensions defining C<PERL_CORE> must be updated now.
509 C<lex_stuff_pvs()> has been added as a convenience macro wrapping
510 C<lex_stuff_pvn()> for literal strings.
514 The recursive part of the peephole optimizer is how hookable.
516 In addition to C<PL_peepp>, for hooking into the toplevel peephole optimizer, a
517 C<PL_rpeepp> is now available to hook into the optimizer recursing into
518 side-chains of the optree.
522 =head1 Selected Bug Fixes
524 XXX Important bug fixes in the core language are summarised here.
525 Bug fixes in files in F<ext/> and F<lib/> are best summarised in
526 L</Modules and Pragmata>.
528 [ List each fix as a =item entry ]
534 A regression introduced in perl 5.12.0, making
535 C<< my $x = 3; $x = length(undef) >> result in C<$x> set to C<3> has been
536 fixed. C<$x> will now be C<undef>.
540 A fatal error in regular expressions when processing UTF-8 data has been fixed
545 An erroneous regular expression engine optimization, that caused regex verbs
546 like C<*COMMIT> to sometimes be ignored, has been removed.
550 The perl debugger now also works in taint mode (RT#76872).
554 Several memory leaks in cloning and freeing threaded perl interpreters have been
559 A possible string corruption when doing regular expression matches on overloaded
560 objects has been fixed (RT#77084).
564 Magic applied to variables in the main package no longer affects other
565 packages. See L</Magic Variables Outside the Main Package>, above [perl #76138].
569 Opening a glob reference via C<< open $fh, ">", \*glob >> will no longer cause
570 the glob to be corrupted when the file handle is printed to. This would cause
571 perl to crash whenever the glob's contents were accessed [perl #77492].
575 The postincrement and postdecrement operators, C<++> and C<--> used to cause
576 leaks when being used on references. This has now been fixed.
580 A bug when replacing the glob of a loop variable within the loop has been
581 fixed [perl #21469]. This means the following code will no longer crash:
589 Perl would segfault if the undocumented C<Internals> functions that
590 used reference prototypes were called with the C<&foo()> syntax,
591 e.g. C<&Internals::SvREADONLY(undef)> [perl #77776].
593 These functions now call C<SvROK> on their arguments before
594 dereferencing them with C<SvRV>, and we test for this case in
595 F<t/lib/universal.t>.
599 When assigning a list with duplicated keys to a hash, the assignment used to
600 return garbage and/or freed values:
602 @a = %h = (list with some duplicate keys);
604 This has now been fixed [perl #31865].
608 An earlier release of the 5.13 series of perl changed the semantics of opening a
609 reference to a copy of a glob:
612 open my $fh, '>', \$var;
614 This was a mistake, and the previous behaviour from perl 5.10 and 5.12, which is
615 to treat \$var as a scalar reference, has now been restored.
619 The regular expression bracketed character class C<[\8\9]> was
620 effectively the same as C<[89\000]>, incorrectly matching a NULL character.
621 It also gave incorrect warnings that the C<8> and C<9> were ignored.
622 Now C<[\8\9]> is the same as C<[89]> and gives legitimate warnings that
623 C<\8> and C<\9> are unrecognized escape sequences, passed-through.
627 C<warn()> now respects utf8-encoded scalars [perl #45549].
631 =head1 Known Problems
633 XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
634 tests that had to be C<TODO>ed for the release would be noted here, unless
635 they were specific to a particular platform (see below).
637 This is a list of some significant unfixed bugs, which are regressions
638 from either 5.XXX.XXX or 5.XXX.XXX.
640 [ List each fix as a =item entry ]
652 XXX If any significant core contributor has died, we've added a short obituary
655 =head1 Acknowledgements
657 XXX The list of people to thank goes here.
659 =head1 Reporting Bugs
661 If you find what you think is a bug, you might check the articles
662 recently posted to the comp.lang.perl.misc newsgroup and the perl
663 bug database at http://rt.perl.org/perlbug/ . There may also be
664 information at http://www.perl.org/ , the Perl Home Page.
666 If you believe you have an unreported bug, please run the B<perlbug>
667 program included with your release. Be sure to trim your bug down
668 to a tiny but sufficient test case. Your bug report, along with the
669 output of C<perl -V>, will be sent off to perlbug@perl.org to be
670 analysed by the Perl porting team.
672 If the bug you are reporting has security implications, which make it
673 inappropriate to send to a publicly archived mailing list, then please send
674 it to perl5-security-report@perl.org. This points to a closed subscription
675 unarchived mailing list, which includes all the core committers, who be able
676 to help assess the impact of issues, figure out a resolution, and help
677 co-ordinate the release of patches to mitigate or fix the problem across all
678 platforms on which Perl is supported. Please only use this address for
679 security issues in the Perl core, not for modules independently
684 The F<Changes> file for an explanation of how to view exhaustive details
687 The F<INSTALL> file for how to build Perl.
689 The F<README> file for general stuff.
691 The F<Artistic> and F<Copying> files for copyright information.