5 perldelta - what is new for perl v5.13.2
9 This document describes differences between the 5.13.2 release and
12 If you are upgrading from an earlier release such as 5.10, first read
13 L<perl5120delta>, which describes differences between 5.10 and
18 XXX Any important notices here
20 =head1 Incompatible Changes
22 =head2 localised tied scalars are tied again.
24 The change in behaviour in 5.13.1 of localising tied scalar values has
25 been reverted to the existing 5.12.0 and earlier behaviour (the change for
26 arrays and hashes remains).
28 =head2 Naming fixes in Policy_sh.SH may invalidate Policy.sh
30 Several long-standing typos and naming confusions in Policy_sh.SH have
31 been fixed, standardizing on the variable names used in config.sh.
33 This will change the behavior of Policy.sh if you happen to have been
34 accidentally relying on the Policy.sh incorrect behavior. We'd appreciate
35 feedback from anyone using Policy.sh to be sure nothing is broken by
38 =head1 Core Enhancements
40 XXX New core language features go here. Summarise user-visible core language
41 enhancements. Particularly prominent performance optimisations could go
42 here, but most should go in the L</Performance Enhancements> section.
44 =head2 Non-destructive substitution
46 The substitution operator now supports a C</r> option that
47 copies the input variable, carries out the substitution on
48 the copy and returns the result. The original remains unmodified.
51 my $new = $old =~ s/cat/dog/r;
52 # $old is 'cat' and $new is 'dog'
54 This is particularly useful with C<map>. See L<perlop> for more examples
57 =head2 package block syntax
59 A package declaration can now contain a code block, in which case the
60 declaration is in scope only inside that block. So C<package Foo { ... }>
61 is precisely equivalent to C<{ package Foo; ... }>. It also works with
62 a version number in the declaration, as in C<package Foo 1.2 { ... }>.
63 See L<perlfunc> (434da3..36f77d, 702646).
65 =head2 perl -h no longer recommends -w
67 perl -h used to mark the -w option as recommended; since this option is
68 far less useful than it used to be due to lexical 'use warnings' and since
69 perl -h is primary a list and brief explanation of the command line switches,
70 the recommendation has now been removed (60eaec).
74 XXX List any platforms that this version of perl compiles on, that previous
75 versions did not. These will either be enabled by new files in the F<hints/>
76 directories, or new subdirectories and F<README> files at the top level of the
79 =head1 Modules and Pragmata
81 XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
82 go here. If Module::CoreList is updated, generate an initial draft of the
83 following sections using F<Porting/corelist-perldelta.pl>, which prints stub
84 entries to STDOUT. Results can be pasted in place of the '=head2' entries
85 below. A paragraph summary for important changes should then be added by hand.
86 In an ideal world, dual-life modules would have a F<Changes> file that could be
89 =head2 New Modules and Pragmata
91 =head2 Pragmata Changes
93 =head2 Updated Modules
95 =head2 Locale-Codes 3.13
97 Locale::Country, Locale::Language and Locale::Currency were updated from
98 3.12 to 3.13 of the Locale-Codes distribution to include locale code changes
101 =head2 Thread-Semaphore 2.11
103 Added new methods ->down_nb() and ->down_force() at the suggestion of Rick
106 Refactored methods to skip argument validation when no argument is supplied.
110 =head2 CPAN.pm 1.94_57
114 * bugfix: treat modules correctly that are deprecated in perl 5.12.
116 * bugfix: RT #57482 and #57788 revealed that configure_requires
117 implicitly assumed build_requires instead of normal requires. (Reported
118 by Andrew Whatson and Father Chrysostomos respectively)
120 * testfix: solaris should run the tests without expect because (some?)
121 solaris have a broken expect
123 * testfix: run tests with cache_metadata off to prevent spill over
124 effects from previous test runs
128 =head2 Removed Modules and Pragmata
130 =head1 Utility Changes
132 XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go
133 here. Most of these are built within the directories F<utils> and F<x2p>.
143 =head1 New Documentation
145 XXX Changes which create B<new> files in F<pod/> go here.
155 =head1 Changes to Existing Documentation
157 XXX Changes which significantly change existing files in F<pod/> go here.
158 Any changes to F<pod/perldiag.pod> should go in L</New or Changed Diagnostics>.
160 =head2 Replace wrong tr/// table in perlebcdic.pod
162 perlebcdic.pod contains a helpful table to use in tr/// to convert
163 between EBCDIC and Latin1/ASCII. Unfortunately, the table was the
164 inverse of the one it describes, though the code that used the table
165 worked correctly for the specific example given.
167 The table has been changed to its inverse, and the sample code changed
168 to correspond, as this is easier for the person trying to follow the
169 instructions since deriving the old table is somewhat more complicated.
171 The table has also been changed to hex from octal, as that is more the norm
172 these days, and the recipes in the pod altered to print out leading
173 zeros to make all the values the same length, as the table that they can
174 generate has them (5f26d5).
176 =head2 Document tricks for user-defined casing
178 perlunicode.pod now contains an explanation of how to override, mangle
179 and otherwise tweak the way perl handles upper, lower and other case
180 conversions on unicode data, and how to provide scoped changes to alter
181 one's own code's behaviour without stomping on anybody else (71648f).
183 =head2 Document $# and $* as removed and clarify $#array usage
185 $# and $* were both disabled as of perl5 version 10; this release adds
186 documentation to that effect, a description of the results of continuing
187 to try and use them, and a note explaining that $# can also function as a
188 sigil in the $#array form (7f315d2).
190 =head2 INSTALL explicitly states the requirement for C89
192 This was already true but it's now Officially Stated For The Record (51eec7).
194 =head2 No longer advertise Math::TrulyRandom
196 This module hasn't been updated since 1996 so we can't recommend it any more
199 =head1 Performance Enhancements
201 Only allocate entries for @_ on demand - this not only saves memory per
202 subroutine defined but should hopefully improve COW behaviour (77bac2).
204 =head2 Multiple small improvements to threads
206 The internal structures of threading now make fewer API calls and fewer
207 allocations, resulting in noticeably smaller object code. Additionally,
208 many thread context checks have been deferred so that they're only done
209 when required (although this is only possible for non-debugging builds).
211 =head2 Size optimisations to SV and HV structures
213 xhv_fill has been eliminated from struct xpvhv, saving 1 IV per hash and
214 on some systems will cause struct xpvhv to become cache aligned. To avoid
215 this memory saving causing a slowdown elsewhere, boolean use of HvFILL
216 now calls HvTOTALKEYS instead (which is equivalent) - so while the fill
217 data when actually required is now calculated on demand, the cases when
218 this needs to be done should be few and far between (f4431c .. fcd245).
220 The order of structure elements in SV bodies has changed. Effectively,
221 the NV slot has swapped location with STASH and MAGIC. As all access to
222 SV members is via macros, this should be completely transparent. This
223 change allows the space saving for PVHVs documented above, and may reduce
224 the memory allocation needed for PVIVs on some architectures.
226 =head2 Optimisation of regexp engine string comparison work
228 The foldEQ_utf8 API function for case-insensitive comparison of strings (which
229 is used heavily by the regexp engine) was substantially refactored and
230 optimised - and its documentation much improved as a free bonus gift
233 =head2 Memory consumption improvements to Exporter
235 The @EXPORT_FAIL AV is no longer created unless required, hence neither is
236 the typeglob backing it - this saves about 200 bytes per Exporter using
237 package that doesn't use this functionality.
239 =head1 Installation and Configuration Improvements
241 XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
244 =head2 Configuration improvements
248 =head2 Compilation improvements
250 Fix CCINCDIR and CCLIBDIR for mingw64 cross compiler to correctly be under
251 $(CCHOME)\mingw\include and \lib rather than immediately below $(CCHOME).
253 This means the 'incpath', 'libpth', 'ldflags', 'lddlflags' and
254 'ldflags_nolargefiles' values in Config.pm and Config_heavy.pl are now
255 set correctly (23ae7f).
257 =head2 Platform Specific Changes
261 =item XXX-some-platform
267 =head1 Selected Bug Fixes
269 Timely cleanup of SVs that are cloned into a new thread but then discovered
270 to be orphaned (i.e. their owners are -not- cloned) (e42956)
272 Don't accidentally clone lexicals in scope within active stack frames in
273 the parent when creating a child thread (RT #73086) (05d04d).
275 Avoid loading feature.pm when 'no 5.13.2;' or similar is encountered (faee19).
277 Trap invalid use of SvIVX on SVt_REGEXP when assertions are on (e77da3)
279 Don't stamp on $DB::single, $DB::trace and $DB::signal if they already have
280 values when $^P is assigned to (RT #72422) (4c0f30).
282 chop now correctly handles perl's extended UTF-8 (RT #73246) (65ab92)
284 Defer signal handling when shared SV locks are held to avoid deadlocks
285 (RT #74868) (65c742).
287 glob() no longer crashes when %File::Glob:: is empty and CORE::GLOBAL::glob
288 isn't present (4984aa).
290 perlbug now always permits the sender address to be changed before sending
291 - if you were having trouble sending bug reports before now, this should
292 fix it, we hope (e6eb90).
298 Overloading now works properly in conjunction with tied variables. What
299 formerly happened was that most ops checked their arguments for overloading
300 I<before> checking for magic, so for example an overloaded object returned
301 by a tied array access would usually be treated as not overloaded
302 (RT #57012) (6f1401, ed3b9b, 6a5f8c .. 24328f).
306 Independently, a bug was fixed that prevented $tied->() from always calling
307 FETCH correctly (RT #8438) (7c7501)
309 =head1 New or Changed Diagnostics
311 XXX New or changed warnings emitted by the core's C<C> code go here.
321 =head1 Changed Internals
323 XXX Changes which affect the interface available to C<XS> code go here.
329 The C<find_rundefsvoffset> function has been deprecated. It appeared that
330 its design was insufficient to reliably get the lexical C<$_> at run-time.
332 Use the new C<find_rundefsv> function or the C<UNDERBAR> macro instead.
333 They directly return the right SV representing C<$_>, whether it's lexical
334 or dynamic (789bd8 .. 03d5bc).
338 The following new functions or macros have been added to the public API:
339 C<SvNV_nomg>, C<sv_2nv_flags>, C<find_rundefsv>.
343 The C<UNDERBAR> macro now calls C<find_rundefsv>. C<dUNDERBAR> is now a
344 noop but should still be used to ensure past and future compatibility.
348 The ibcmp_* functions have been renamed and are now called foldEQ,
349 foldEQ_locale and foldEQ_utf8 (e6226b).
353 The ibcmp_* functions have been renamed and are now called foldEQ,
354 foldEQ_locale and foldEQ_utf8 (e6226b).
360 XXX Changes which create B<new> files in F<t/> go here. Changes to
361 existing files in F<t/> aren't worth summarising, although the bugs that
362 they represent may be.
372 =head1 Known Problems
374 XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
375 tests that had to be C<TODO>ed for the release would be noted here, unless
376 they were specific to a particular platform (see below).
378 This is a list of some significant unfixed bugs, which are regressions
379 from either 5.XXX.XXX or 5.XXX.XXX.
391 XXX Add any new known deprecations here.
393 The following items are now deprecated.
399 Omitting a space between a regex pattern or pattern modifiers and the following
400 word is deprecated. For example, C<< m/foo/sand $bar >> will still be parsed
401 as C<< m/foo/s and $bar >> but will issue a warning.
405 =head1 Platform Specific Notes
407 =head2 Recent OpenBSDs now use perl's malloc
409 OpenBSD > 3.7 has a new malloc implementation which is mmap based and as such
410 can release memory back to the OS; however for perl using this malloc causes
411 a substantial slowdown so we now default to using perl's malloc instead
412 (RT #75742) (9b58b5).
416 XXX If any significant core contributor has died, we've added a short obituary
419 =head1 Acknowledgements
421 XXX The list of people to thank goes here.
423 Your humble release manager would like to specifically call out
424 Karl Williamson for making the tests a better place to be, and Shlomi
425 Fish for a passel of tiny incremental docfixes of the sort that don't get
428 =head1 Reporting Bugs
430 If you find what you think is a bug, you might check the articles
431 recently posted to the comp.lang.perl.misc newsgroup and the perl
432 bug database at http://rt.perl.org/perlbug/ . There may also be
433 information at http://www.perl.org/ , the Perl Home Page.
435 If you believe you have an unreported bug, please run the B<perlbug>
436 program included with your release. Be sure to trim your bug down
437 to a tiny but sufficient test case. Your bug report, along with the
438 output of C<perl -V>, will be sent off to perlbug@perl.org to be
439 analysed by the Perl porting team.
441 If the bug you are reporting has security implications, which make it
442 inappropriate to send to a publicly archived mailing list, then please send
443 it to perl5-security-report@perl.org. This points to a closed subscription
444 unarchived mailing list, which includes all the core committers, who be able
445 to help assess the impact of issues, figure out a resolution, and help
446 co-ordinate the release of patches to mitigate or fix the problem across all
447 platforms on which Perl is supported. Please only use this address for
448 security issues in the Perl core, not for modules independently
453 The F<Changes> file for an explanation of how to view exhaustive details
456 The F<INSTALL> file for how to build Perl.
458 The F<README> file for general stuff.
460 The F<Artistic> and F<Copying> files for copyright information.