5 perl5138delta - what is new for perl v5.13.8
9 This document describes differences between the 5.13.7 release and
12 If you are upgrading from an earlier release such as 5.13.6, first read
13 L<perl5137delta>, which describes differences between 5.13.6 and
16 =head1 Core Enhancements
18 =head2 C<-d:-foo> calls C<Devel::foo::unimport>
20 The syntax C<-dI<B<:>foo>> was extended in 5.6.1 to make C<-dI<:fooB<=bar>>>
21 equivalent to C<-MDevel::foo=bar>, which expands
22 internally to C<use Devel::foo 'bar';>.
23 F<perl> now allows prefixing the module name with C<->, with the same
24 semantics as C<-M>, I<i.e.>
30 Equivalent to C<-M-Devel::foo>, expands to
31 C<no Devel::foo;>, calls C<< Devel::foo->unimport() >>
36 Equivalent to C<-M-Devel::foo=bar>, expands to C<no Devel::foo 'bar';>,
37 calls C<< Devel::foo->unimport('bar') >> if the method exists.
41 This is particularly useful to suppresses the default actions of a
42 C<Devel::*> module's C<import> method whilst still loading it for debugging.
44 =head2 Filehandle method calls load L<IO::File> on demand
46 When a method call on a filehandle would die because the method cannot
47 be resolved, and L<IO::File> has not been loaded, Perl now loads L<IO::File>
48 via C<require> and attempts method resolution again:
50 open my $fh, ">", $file;
51 $fh->binmode(":raw"); # loads IO::File and succeeds
53 This also works for globs like STDOUT, STDERR and STDIN:
57 Because this on-demand load only happens if method resolution fails, the
58 legacy approach of manually loading an L<IO::File> parent class for partial
59 method support still works as expected:
62 open my $fh, ">", $file;
63 $fh->autoflush(1); # IO::File not loaded
65 =head2 Full functionality for C<use feature 'unicode_strings'>
67 This release provides full functionality for C<use feature
68 'unicode_strings'>. Under its scope, all string operations executed and
69 regular expressions compiled (even if executed outside its scope) have
70 Unicode semantics. See L<feature>.
72 This feature avoids most forms of the "Unicode Bug" (See
73 L<perlunicode/The "Unicode Bug"> for details.) If there is a
74 possibility that your code will process Unicode strings, you are
75 B<strongly> encouraged to use this subpragma to avoid nasty surprises.
77 The availability of this should strongly affect the whole tone of
78 various documents, such as L<perlunicode> and L<perluniintro>, but this
79 work has not been done yet.
81 =head2 Exception Handling Backcompat Hack
83 When an exception is thrown in an C<eval BLOCK>, C<$@> is now set before
84 unwinding, as well as being set after unwinding as the eval block exits. This
85 early setting supports code that has historically treated C<$@> during unwinding
86 as an indicator of whether the unwinding was due to an exception. These modules
87 had been broken by 5.13.1's change from setting C<$@> early to setting it late.
88 This double setting arrangement is a stopgap until the reason for unwinding can
89 be made properly introspectable. C<$@> has never been a reliable indicator of
90 the reason for unwinding.
92 =head2 printf-like functions understand post-1980 size modifiers
94 Perl's printf and sprintf operators, and Perl's internal printf replacement
95 function, now understand the C90 size modifiers "hh" (C<char>), "z"
96 (C<size_t>), and "t" (C<ptrdiff_t>). Also, when compiled with a C99
97 compiler, Perl now understands the size modifier "j" (C<intmax_t>).
99 So, for example, on any modern machine, C<sprintf('%hhd', 257)> returns '1'.
101 =head2 DTrace probes now include package name
103 The DTrace probes now include an additional argument (C<arg3>) which contains
104 the package the subroutine being entered or left was compiled in.
106 For example using the following DTrace script:
108 perl$target:::sub-entry
110 printf("%s::%s\n", copyinstr(arg0), copyinstr(arg3));
115 perl -e'sub test { }; test'
121 =head2 Stacked labels
123 Multiple statement labels can now appear before a single statement.
125 =head1 Incompatible Changes
127 =head2 C<:=> is now a syntax error
129 Previously C<my $pi := 4;> was exactly equivalent to C<my $pi : = 4;>,
130 with the C<:> being treated as the start of an attribute list, ending before
131 the C<=>. The use of C<:=> to mean C<: => was deprecated in 5.12.0, and is now
132 a syntax error. This will allow the future use of C<:=> as a new token.
134 We find no Perl 5 code on CPAN using this construction, outside the core's
135 tests for it, so we believe that this change will have very little impact on
136 real-world codebases.
138 If it is absolutely necessary to have empty attribute lists (for example,
139 because of a code generator) then avoid the error by adding a space before
142 =head2 Run-time code block in regular expressions
144 Code blocks in regular expressions (C<(?{...})> and C<(??{...})>) used not
145 to inherit any pragmata (strict, warnings, etc.) if the regular expression
146 was compiled at run time as happens in cases like these two:
149 $foo =~ $bar; # when $bar contains (?{...})
150 $foo =~ /$bar(?{ $finished = 1 })/;
152 This was a bug, which has now been fixed. But it has the potential to break
153 any code that was relying on this bug.
157 =head2 C<?PATTERN?> is deprecated
159 C<?PATTERN?> (without the initial m) has been deprecated and now produces
160 a warning. This is to allow future use of C<?> in new operators.
161 The match-once functionality is still available in the form of C<m?PATTERN?>.
163 =head2 C<sv_compile_2op()> is now deprecated
165 The C<sv_compile_2op()> API function is now deprecated. Searches suggest
166 that nothing on CPAN is using it, so this should have zero impact.
168 It attempted to provide an API to compile code down to an optree, but failed
169 to bind correctly to lexicals in the enclosing scope. It's not possible to
170 fix this problem within the constraints of its parameters and return value.
172 =head2 Tie functions on scalars holding typeglobs
174 Calling a tie function (C<tie>, C<tied>, C<untie>) with a scalar argument
175 acts on a file handle if the scalar happens to hold a typeglob.
177 This is a long-standing bug that will be removed in Perl 5.16, as
178 there is currently no way to tie the scalar itself when it holds
179 a typeglob, and no way to untie a scalar that has had a typeglob
182 This bug was fixed in 5.13.7 but, because of the breakage it caused, the
183 fix has been reverted. Now there is a deprecation warning whenever a tie
184 function is used on a handle without an explicit C<*>.
186 =head1 Modules and Pragmata
188 =head2 Updated Modules and Pragmata
194 C<Archive::Tar> has been upgraded from version 1.72 to 1.74.
196 Skip extracting pax extended headers.
200 C<autodie> has been upgraded from version 2.10 to 2.1001.
202 Test fix in blead for VMS.
206 C<B> has been upgraded from version 1.26 to 1.27.
208 Avoid compiler warnings.
212 C<B::Concise> has been upgraded from version 0.81 to 0.82.
214 It no longer produces mangled output with the C<-tree> option
215 L<[perl #80632]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=80632>.
219 C<B::Deparse> has been upgraded from version 1.01 to 1.02.
225 C<Cwd> has been upgraded from version 3.34 to 3.35.
227 Avoid compiler warnings.
231 C<Data::Dumper> has been upgraded from version 2.130_01 to 2.130_02.
233 Avoid compiler warnings.
237 C<Devel::Peek> has been upgraded from version 1.05 to 1.06.
239 Avoid compiler warnings.
245 C<Devel::SelfStubber> has been upgraded from version 1.03 to 1.05.
251 C<Digest::SHA> has been upgraded from 5.48 to 5.50.
253 C<shasum> now more closely mimics C<sha1sum>/C<md5sum>.
255 C<Addfile> accepts all POSIX filenames.
259 C<Dumpvalue> has been upgraded from version 1.14 to 1.15.
265 C<DynaLoader> has been upgraded from version 1.11 to 1.12.
267 Remove obsolete RCS keywords.
271 C<Env> has been upgraded from version 1.01 to 1.02.
277 C<ExtUtils::CBuilder> has been upgraded from 0.2703 to 0.280201.
279 Handle C and C++ compilers separately.
281 Preserves exit status on VMS.
287 C<ExtUtils::Constant::Utils> has been upgraded from 0.02 to 0.03.
289 Refactoring and fixing of backcompat code, preparing for resynchronisation
294 C<ExtUtils::Embed> has been upgraded from 1.29 to 1.30.
296 Remove obsolete RCS keywords.
300 C<ExtUtils::ParseXS> has been upgraded from 2.2207 to 2.2208.
302 Avoid compiler warnings.
306 C<Fcntl> has been upgraded from 1.10 to 1.11.
308 Avoid compiler warnings.
314 C<feature> has been upgraded from 1.18 to 1.19.
316 Documentation and test updates for the C<unicode_strings> feature.
317 See L</Full functionality for C<use feature 'unicode_strings'>>.
321 C<File::CheckTree> has been upgraded from 4.4 to 4.41.
327 C<File::Glob> has been upgraded from 1.10 to 1.11.
329 Avoid compiler warnings.
335 C<GDBM_File> has been upgraded from 1.12 to 1.13.
339 Remove obsolete RCS keywords.
343 C<Hash::Util::FieldHash> has been upgraded from 1.06 to 1.07.
345 Avoid compiler warnings.
349 C<I18N::Collate> has been upgraded from 1.01 to 1.02.
357 C<if> has been upgraded from 0.06 to 0.0601.
363 C<IO> has been upgraded from 1.25_02 to 1.25_03.
365 Avoid compiler warnings.
369 C<IPC::Cmd> has been upgraded from 0.64 to 0.66.
371 Resolves an issue with splitting Win32 command lines.
373 Documentation enhancements.
377 C<IPC::Open3> has been upgraded from 1.07 to 1.08.
379 Remove obsolete RCS keywords.
385 C<Locale::Codes> has been upgraded from version 3.14 to 3.15.
391 C<Math::BigInt> has been upgraded from 1.99_01 to 1.99_02.
393 Documentation and comment spelling fixes.
397 C<Memoize> has been upgraded from version 1.01_03 to 1.02.
399 Remove obsolete RCS keywords.
405 C<MIME::Base64> has been upgraded from 3.10 to 3.13.
407 Now provides C<encode_base64url> and C<decode_base64url> functions to process
408 the base64 scheme for "URL applications".
412 C<mro> has been upgraded from version 1.05 to 1.06.
414 C<next::method> I<et al.> now take into account that every class inherits
416 L<[perl #68654]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=68654>.
420 C<NDBM_File> has been upgraded from 1.10 to 1.11.
422 Remove obsolete RCS keywords.
428 C<Net::Ping> has been upgraded from 2.36 to 2.37.
430 Remove obsolete RCS keywords.
434 C<ODBM_File> has been upgraded from 1.09 to 1.10.
436 Remove obsolete RCS keywords.
442 C<Opcode> has been upgraded from 1.17 to 1.18.
444 Avoid compiler warnings.
450 C<overload> has been upgraded from 1.11 to 1.12.
452 Avoid a taint problem in use of sprintf.
454 Test asymmetric fallback cases
455 L<[perl #71286]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=71286>.
459 C<PerlIO::encoding> has been upgraded from 0.13 to 0.14.
461 Avoid compiler warnings.
463 Remove obsolete RCS keywords.
469 C<PerlIO::scalar> has been upgraded from 0.10 to 0.11.
471 A C<read> after a C<seek> beyond the end of the string no longer thinks it
473 L<[perl #78716]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=78716>.
475 Avoid compiler warnings.
479 C<PerlIO::via> has been upgraded from 0.10 to 0.11.
481 Avoid compiler warnings.
485 C<POSIX> has been upgraded from 1.22 to 1.23.
487 Avoid compiler warnings.
491 C<re> has been upgraded from 0.14 to 0.15.
493 Enforce that C</d>, C</u>, and C</l> are mutually exclusive.
497 C<SDBM_File> has been upgraded from 1.08 to 1.09.
499 Avoid compiler warnings.
501 Remove obsolete RCS keywords.
507 C<Socket> has been upgraded from 1.91 to 1.92.
509 It has several new functions for handling IPv6 addresses.
513 C<Storable> has been upgraded from 2.24 to 2.25.
515 This adds support for serialising code references that contain UTF-8 strings
516 correctly. The Storable minor version number changed as a result, meaning that
517 Storable users who set C<$Storable::accept_future_minor> to a C<FALSE> value
518 will see errors (see L<Storable/FORWARD COMPATIBILITY> for more details).
520 Freezing no longer gets confused if the Perl stack gets reallocated
522 L<[perl #80074]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=80074>.
524 Avoid compiler warnings.
528 C<threads> has been upgraded from 1.81_02 to 1.81_03.
530 Avoid compiler warnings.
534 C<threads::shared> has been upgraded from 1.34 to 1.35.
536 Avoid compiler warnings.
540 C<Time::HiRes> has been upgraded from 1.9721 to 1.9721_01.
542 Build fix in blead for VMS.
546 C<Unicode::Collate> has been upgraded from 0.67 to 0.6801.
548 Documentation clarification.
554 C<Unicode::Normalize> has been upgraded from 1.07 to 1.08.
556 Avoid compiler warnings.
560 C<Unicode::UCD> has been upgraded from 0.29 to 0.30.
562 Add info about named sequence alternatives.
564 Don't use C<CompositionExclusions.txt>.
568 C<version> has been upgraded from 0.82 to 0.86.
570 Modify export logic for C<is_strict> and C<is_lax>.
572 Various backcompat fixes.
576 C<Win32> has been upgraded from 0.39 to 0.41.
578 Add several functions.
580 Corrections to names returned by C<Win32::GetOSName> and
581 C<Win32::GetOSDisplayName>.
585 C<XS::APItest> has been upgraded from 0.26 to 0.27.
587 Test new API functions.
589 Avoid compiler warnings.
593 =head2 Dual-life Modules and Pragmata
595 These modules were formerly distributed only in the Perl core
596 distribution, and are now dual-lifed (meaning they are now also available
607 C<Devel::SelfStubber>
629 The following additions or changes have been made to diagnostic output,
630 including warnings and fatal error messages. For the complete list of
631 diagnostic messages, see L<perldiag>.
633 =head2 New Diagnostics
639 There is a new "Closure prototype called" error
640 L<[perl #68560]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=68560>.
644 =head2 Changes to Existing Diagnostics
650 The "Found = in conditional" warning that is emitted when a constant is
651 assigned to a variable in a condition is now withheld if the constant is
652 actually a subroutine or one generated by C<use constant>, since the value
653 of the constant may not be known at the time the program is written
654 L<[perl #77762]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=77762>.
658 =head1 Configuration and Compilation
664 The C<Encode> module can now (once again) be included in a static Perl
665 build. The special-case handling for this situation got broken in Perl
666 5.11.0, and has now been repaired.
676 Tests for C<Fcntl>, C<File::Glob>, C<GDBM_File>, C<IPC::Open3>,
677 C<NDBM_File>, C<ODBM_File>, C<Opcode>, C<PerlIO::encoding>, C<SDBM_File>,
678 and C<Storable> now use the L<Test::More> framework.
682 =head1 Platform Support
684 =head2 Platform-Specific Notes
690 The NetBSD hints file has been changed to make the system's malloc the
695 The option to use an externally-supplied C<crypt()>, or to build with no
696 C<crypt()> at all, has been removed. Perl supplies its own C<crypt()>
697 implementation for Windows, and the political situation that required
698 this part of the distribution to sometimes be omitted is long gone.
702 =head1 Internal Changes
708 The L<C<mg_findext()>|perlapi/mg_findext> and
709 L<C<sv_unmagicext()>|perlapi/sv_unmagicext>
710 functions have been added to the API.
711 They allow extension authors to find and remove magic attached to
712 scalars based on both the magic type and the magic virtual table, similar to how
713 C<sv_magicext()> attaches magic of a certain type and with a given virtual table
714 to a scalar. This eliminates the need for extensions to walk the list of
715 C<MAGIC> pointers of an C<SV> to find the magic that belongs to them.
720 L<C<parse_fullexpr()>|perlapi/parse_fullexpr>,
721 L<C<parse_listexpr()>|perlapi/parse_listexpr>,
722 L<C<parse_termexpr()>|perlapi/parse_termexpr>, and
723 L<C<parse_arithexpr()>|perlapi/parse_arithexpr>
724 functions have been added to the API. They perform
725 recursive-descent parsing of expressions at various precedence levels.
726 They are expected to be used by syntax plugins.
730 =head1 Selected Bug Fixes
736 C<BEGIN {require 5.12.0}> now behaves as documented, rather than behaving
737 identically to C<use 5.12.0;>. Previously, C<require> in a C<BEGIN> block
738 was erroneously executing the C<use feature ':5.12.0'> and
739 C<use strict; use warnings;> behaviour, which only C<use> was documented to
741 L<[perl #69050]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=69050>.
746 L<[perl #69050]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=69050>,
747 C<use 6> and C<no 5> no longer leak memory.
751 C<eval "BEGIN{die}"> no longer leaks memory on non-threaded builds.
755 PerlIO no longer crashes when called recursively, e.g., from a signal
756 handler. Now it just leaks memory
757 L<[perl #75556]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=75556>.
761 Defining a constant with the same name as one of perl's special blocks
762 (e.g., INIT) stopped working in 5.12.0, but has now been fixed
763 L<[perl #78634]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=78634>.
767 A reference to a literal value used as a hash key (C<$hash{\"foo"}>) used
768 to be stringified, even if the hash was tied
769 L<[perl #79178]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=79178>.
773 A closure containing an C<if> statement followed by a constant or variable
774 is no longer treated as a constant
775 L<[perl #63540]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=63540>.
779 Calling a closure prototype (what is passed to an attribute handler for a
780 closure) now results in a "Closure prototype called" error message instead
782 L<[perl #68560]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=68560>.
786 A regular expression optimisation would sometimes cause a match with a
787 C<{n,m}> quantifier to fail when it should match
788 L<[perl #79152]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=79152>.
792 What has become known as the "Unicode Bug" is mostly resolved in this release.
793 Under C<use feature 'unicode_strings'>, the internal storage format of a
794 string no longer affects the external semantics. There are two known
795 exceptions. User-defined case changing functions, which are planned to
796 be deprecated in 5.14, require utf8-encoded strings to function; and the
797 character C<LATIN SMALL LETTER SHARP S> in regular expression
798 case-insensitive matching has a somewhat different set of bugs depending
799 on the internal storage format. Case-insensitive matching of all
800 characters that have multi-character matches, as this one does, is
801 problematical in Perl.
802 L<[perl #58182]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=58182>.
806 Mentioning a read-only lexical variable from the enclosing scope in a
807 string C<eval> no longer causes the variable to become writable
808 L<[perl #19135]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=19135>.
812 C<state> can now be used with attributes. It used to mean the same thing as
813 C<my> if attributes were present
814 L<[perl #68658]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=68658>.
818 Expressions like C<< @$a > 3 >> no longer cause C<$a> to be mentioned in
819 the "Use of uninitialized value in numeric gt" warning when C<$a> is
820 undefined (since it is not part of the C<E<gt>> expression, but the operand
822 L<[perl #72090]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=72090>.
826 C<require> no longer causes C<caller> to return the wrong file name for
827 the scope that called C<require> and other scopes higher up that had the
829 L<[perl #68712]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=68712>.
833 The ref types in the typemap for XS bindings now support magical variables
834 L<[perl #72684]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=72684>.
838 Match variables (e.g., C<$1>) no longer persist between calls to a sort
840 L<[perl #76026]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=76026>.
844 The C<B> module was returning C<B::OP>s instead of C<B::LOGOP>s for C<entertry>
845 L<[perl #80622]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=80622>.
846 This was due to a bug in the perl core, not in C<B> itself.
850 Some numeric operators were converting integers to floating point,
851 resulting in loss of precision on 64-bit platforms
852 L<[perl #77456]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=77456>.
856 The fallback behaviour of overloading on binary operators was asymmetric
857 L<[perl #71286]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=71286>.
861 =head1 Acknowledgements
863 Perl 5.13.8 represents approximately one month of development since
864 Perl 5.13.7 and contains 38715 lines of changes across 546 files from
865 38 authors and committers.
867 Thank you to the following for contributing to this release:
869 Abhijit Menon-Sen, Abigail, Andreas KE<0xf6>nig, Ben Morrow, Brad Gilbert,
870 brian d foy, Chip Salzenberg, Chris 'BinGOs' Williams, Craig A. Berry,
871 David Golden, David Leadbeater, David Mitchell, Father Chrysostomos,
872 Florian Ragwitz, Goro Fuji, H.Merijn Brand, Jan Dubois, Jerry D. Hedden,
873 Jesse Vincent, John Peacock, Karl Williamson, Lukas Mai, Marvin Humphrey,
874 Max Maischein, Michael Breen, Michael Fig, Nicholas Clark, Nick Cleaton,
875 Paul Evans, Peter J. Holzer, Peter John Acklam, Rafael Garcia-Suarez,
876 Reini Urban, Renee Baecker, Ricardo Signes, Tony Cook, Yves Orton, Zefram
878 =head1 Reporting Bugs
880 If you find what you think is a bug, you might check the articles
881 recently posted to the comp.lang.perl.misc newsgroup and the perl
882 bug database at http://rt.perl.org/perlbug/ . There may also be
883 information at http://www.perl.org/ , the Perl Home Page.
885 If you believe you have an unreported bug, please run the L<perlbug>
886 program included with your release. Be sure to trim your bug down
887 to a tiny but sufficient test case. Your bug report, along with the
888 output of C<perl -V>, will be sent off to perlbug@perl.org to be
889 analysed by the Perl porting team.
891 If the bug you are reporting has security implications, which make it
892 inappropriate to send to a publicly archived mailing list, then please send
893 it to perl5-security-report@perl.org. This points to a closed subscription
894 unarchived mailing list, which includes all the core committers, who be able
895 to help assess the impact of issues, figure out a resolution, and help
896 co-ordinate the release of patches to mitigate or fix the problem across all
897 platforms on which Perl is supported. Please only use this address for
898 security issues in the Perl core, not for modules independently
903 The F<Changes> file for an explanation of how to view exhaustive details
906 The F<INSTALL> file for how to build Perl.
908 The F<README> file for general stuff.
910 The F<Artistic> and F<Copying> files for copyright information.