=head1 NAME
-[ this is a template for a new perldelta file. Any text flagged as XXX needs
-to be processed before release. ]
-
-perldelta - what is new for perl v5.23.2
+perldelta - what is new for perl v5.23.4
=head1 DESCRIPTION
-This document describes differences between the 5.23.1 release and the 5.23.2
+This document describes differences between the 5.23.3 release and the 5.23.4
release.
-If you are upgrading from an earlier release such as 5.23.0, first read
-L<perl5231delta>, which describes differences between 5.23.0 and 5.23.1.
+If you are upgrading from an earlier release such as 5.23.2, first read
+L<perl5233delta>, which describes differences between 5.23.2 and 5.23.3.
-=head1 Notice
+=head1 Incompatible Changes
-XXX Any important notices here
+=head2 Lexical $_ has been removed
-=head1 Core Enhancements
+C<my $_> was introduced in Perl 5.10, and subsequently caused much confusion
+with no obvious solution. In Perl 5.18.0, it was made experimental on the
+theory that it would either be removed or redesigned in a less confusing (but
+backward-incompatible) way. Over the following years, no alternatives were
+proposed. The feature has now been removed and will fail to compile.
-XXX New core language features go here. Summarize user-visible core language
-enhancements. Particularly prominent performance optimisations could go
-here, but most should go in the L</Performance Enhancements> section.
+=head2 Only blanks and tabs are now allowed within C<[...]> within C<(?[...])>.
-[ List each enhancement as a =head2 entry ]
+The experimental Extended Bracketed Character Classes can contain regular
+bracketed character classes within them. These differ from regular ones in
+that white space is generally ignored, unless escaped by preceding it with a
+backslash. The white space that is ignored is now limited to just tab C<\t>
+and SPACE characters. Previously, it was any white space. See
+L<perlrecharclass/Extended Bracketed Character Classes>.
-=head1 Security
+=head1 Performance Enhancements
-XXX Any security-related notices go here. In particular, any security
-vulnerabilities closed should be noted here rather than in the
-L</Selected Bug Fixes> section.
+=over 4
-[ List each security issue as a =head2 entry ]
+=item *
-=head1 Incompatible Changes
+C</fixed-substr/> has been made much faster.
-XXX For a release on a stable branch, this section aspires to be:
+On platforms with a libc memchr() implementation which makes good use of
+underlying hardware support, patterns which include fixed substrings will now
+often be much faster; for example with glibc on a recent x86_64 CPU, this:
- There are no changes intentionally incompatible with 5.XXX.XXX
- If any exist, they are bugs, and we request that you submit a
- report. See L</Reporting Bugs> below.
+ $s = "a" x 1000 . "wxyz";
+ $s =~ /wxyz/ for 1..30000
-[ List each incompatible change as a =head2 entry ]
+is now about 7 times faster. On systems with slow memchr(), e.g. 32-bit ARM
+Raspberry Pi, there will be a small or little speedup. Conversely, some
+pathological cases, such as C<"ab" x 1000 =~ /aa/> will be slower now; up to 3
+times slower on the rPi, 1.5x slower on x86_64.
-=head1 Deprecations
+=back
-XXX Any deprecated features, syntax, modules etc. should be listed here.
+=head1 Modules and Pragmata
-=head2 Module removals
+=head2 Updated Modules and Pragmata
-XXX Remove this section if inapplicable.
+=over 4
-The following modules will be removed from the core distribution in a
-future release, and will at that time need to be installed from CPAN.
-Distributions on CPAN which require these modules will need to list them as
-prerequisites.
+=item *
-The core versions of these modules will now issue C<"deprecated">-category
-warnings to alert you to this fact. To silence these deprecation warnings,
-install the modules in question from CPAN.
+L<B> has been upgraded from version 1.59 to 1.60.
-Note that these are (with rare exceptions) fine modules that you are encouraged
-to continue to use. Their disinclusion from core primarily hinges on their
-necessity to bootstrapping a fully functional, CPAN-capable Perl installation,
-not usually on concerns over their design.
+=item *
-=over
+L<bignum> has been upgraded from version 0.40 to 0.41.
-=item XXX
+=item *
-XXX Note that deprecated modules should be listed here even if they are listed
-as an updated module in the L</Modules and Pragmata> section.
+L<Compress::Raw::Bzip2> has been upgraded from version 2.068 to 2.069.
-=back
+=item *
-[ List each other deprecation as a =head2 entry ]
+L<Compress::Raw::Zlib> has been upgraded from version 2.068_01 to 2.069.
-=head1 Performance Enhancements
+=item *
-XXX Changes which enhance performance without changing behaviour go here.
-There may well be none in a stable release.
+L<Devel::PPPort> has been upgraded from version 3.31 to 3.32.
-[ List each enhancement as a =item entry ]
+=item *
-=over 4
+L<DynaLoader> has been upgraded from version 1.34 to 1.35.
=item *
-XXX
+L<Encode> has been upgraded from version 2.77 to 2.78.
-=back
+=item *
-=head1 Modules and Pragmata
+L<experimental> has been upgraded from version 0.014 to 0.016.
-XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
-go here. If Module::CoreList is updated, generate an initial draft of the
-following sections using F<Porting/corelist-perldelta.pl>. A paragraph summary
-for important changes should then be added by hand. In an ideal world,
-dual-life modules would have a F<Changes> file that could be cribbed.
+=item *
-[ Within each section, list entries as a =item entry ]
+L<ExtUtils::CBuilder> has been upgraded from version 0.280223 to 0.280224.
-=head2 New Modules and Pragmata
+=item *
-=over 4
+L<File::Path> has been upgraded from version 2.11 to 2.12.
=item *
-XXX
+L<if> has been upgraded from version 0.0605 to 0.0606.
-=back
+=item *
-=head2 Updated Modules and Pragmata
+L<IO> has been upgraded from version 1.35 to 1.36.
-=over 4
+For an IO::Poll object C<$poll> with no file handles yet in it,
+C<$poll-E<gt>poll(10)> now sleeps for up to 10 seconds anyway instead of
+returning 0 immediately.
+L<[cpan #25049]|https://rt.cpan.org/Ticket/Display.html?id=25049>
=item *
-L<XXX> has been upgraded from version A.xx to B.yy.
+The IO-Compress modules have been upgraded from version 2.068 to 2.069.
-=back
+=item *
-=head2 Removed Modules and Pragmata
+L<Math::BigInt> has been upgraded from version 1.999701 to 1.999704.
-=over 4
+=item *
+
+L<Math::BigInt::FastCalc> has been upgraded from version 0.31 to 0.34.
=item *
-XXX
+L<Module::CoreList> has been upgraded from version 5.20150920 to 5.20151020.
-=back
+=item *
-=head1 Documentation
+L<Module::Metadata> has been upgraded from version 1.000027 to 1.000029.
-XXX Changes to files in F<pod/> go here. Consider grouping entries by
-file and be sure to link to the appropriate page, e.g. L<perlfunc>.
+=item *
-=head2 New Documentation
+L<Perl::OSType> has been upgraded from version 1.008 to 1.009.
-XXX Changes which create B<new> files in F<pod/> go here.
+=item *
-=head3 L<XXX>
+L<PerlIO::encoding> has been upgraded from version 0.21 to 0.22.
-XXX Description of the purpose of the new file here
+PerlIO::encoding objects are now properly duplicated.
+L<[perl #31923]|https://rt.perl.org/Ticket/Display.html?id=31923>
-=head2 Changes to Existing Documentation
+=item *
-XXX Changes which significantly change existing files in F<pod/> go here.
-However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
-section.
+L<POSIX> has been upgraded from version 1.57 to 1.58.
-=head3 L<XXX>
+If C<POSIX::strerror> was passed C<$!> as its argument then it accidentally
+cleared C<$!>. This has been fixed.
+L<[perl #126229]|https://rt.perl.org/Ticket/Display.html?id=126229>
-=over 4
+=item *
+
+L<Socket> has been upgraded from version 2.020_01 to 2.020_02.
+
+Various fixes have been applied to inet_pton for the benefit of MS VC++ builds
+on Windows. In particular, this restores the build with MS VC++ 6.0.
=item *
-XXX Description of the change here
+L<Unicode::Normalize> has been upgraded from version 1.19 to 1.21.
-=back
+=item *
-=head1 Diagnostics
+L<warnings> has been upgraded from version 1.33 to 1.35.
-The following additions or changes have been made to diagnostic output,
-including warnings and fatal error messages. For the complete list of
-diagnostic messages, see L<perldiag>.
+The C<warnings::enabled> example now actually uses C<warnings::enabled>.
+L<[perl #126051]|https://rt.perl.org/Ticket/Display.html?id=126051>
-XXX New or changed warnings emitted by the core's C<C> code go here. Also
-include any changes in L<perldiag> that reconcile it to the C<C> code.
+=back
-=head2 New Diagnostics
+=head1 Documentation
-XXX Newly added diagnostic messages go under here, separated into New Errors
-and New Warnings
+=head2 Changes to Existing Documentation
-=head3 New Errors
+=head3 L<perlapi>
=over 4
=item *
-XXX L<message|perldiag/"message">
+The process of using undocumented globals has been documented, namely, that one
+should send email to L<perl5-porters@perl.org|mailto:perl5-porters@perl.org>
+first to get the go-ahead for documenting and using an undocumented function or
+global variable.
=back
-=head3 New Warnings
+=head3 L<perlsub>
=over 4
=item *
-XXX L<message|perldiag/"message">
+Updated to note that anonymous subroutines can have signatures.
=back
-=head2 Changes to Existing Diagnostics
+=head3 L<perltie>
+
+=over 4
+
+=item *
+
+The usage of C<FIRSTKEY> and C<NEXTKEY> has been clarified.
-XXX Changes (i.e. rewording) of diagnostic messages go here
+=back
+
+=head3 L<perlvar>
=over 4
=item *
-XXX Describe change here
+The specific true value of C<$!{E...}> is now documented, noting that it is
+subject to change and not guaranteed.
=back
-=head1 Utility Changes
+=head1 Diagnostics
-XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go here.
-Most of these are built within the directory F<utils>.
+The following additions or changes have been made to diagnostic output,
+including warnings and fatal error messages. For the complete list of
+diagnostic messages, see L<perldiag>.
-[ List utility changes as a =head2 entry for each utility and =item
-entries for each change
-Use L<XXX> with program names to get proper documentation linking. ]
+=head2 New Diagnostics
-=head2 L<XXX>
+=head3 New Errors
=over 4
=item *
-XXX
+L<Can't find Unicode property definition "%s" in regex;|perldiag/"Can't find Unicode property definition "%s" in regex; marked by <-- HERE in m/%s/">
-=back
+=item *
-=head1 Configuration and Compilation
+L<Character following \p must be '{' or a single-character Unicode property name in regex;|perldiag/"Character following \%c must be '{' or a single-character Unicode property name in regex; marked by <-- HERE in m/%s/">
-XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
-go here. Any other changes to the Perl build process should be listed here.
-However, any platform-specific changes should be listed in the
-L</Platform Support> section, instead.
+=item *
-[ List changes as a =item entry ].
+L<Illegal user-defined property name|perldiag/"Illegal user-defined property name">
+
+=back
+
+=head2 Changes to Existing Diagnostics
=over 4
=item *
-XXX
+L<Can't modify non-lvalue subroutine call of &%s|perldiag/"Can't modify non-lvalue subroutine call of &%s">
+
+This error now reports the name of the non-lvalue subroutine you attempted to
+use as an lvalue.
=back
-=head1 Testing
+=head1 Configuration and Compilation
-XXX Any significant changes to the testing of a freshly built perl should be
-listed here. Changes which create B<new> files in F<t/> go here as do any
-large changes to the testing harness (e.g. when parallel testing was added).
-Changes to existing files in F<t/> aren't worth summarizing, although the bugs
-that they represent may be covered elsewhere.
+=over 4
-[ List each test improvement as a =item entry ]
+=item *
-=over 4
+Using the C<NO_HASH_SEED> define in combination with the default hash algorithm
+C<PERL_HASH_FUNC_ONE_AT_A_TIME_HARD> resulted in a fatal error while compiling
+the interpreter, since Perl 5.17.10. This has been fixed.
=item *
-XXX
+If you had F<Configure> hints for C<d_procselfexe> or C<procselfexe>, they were
+probably broken by the AmigaOS changes in Perl 5.23.3. This has been now
+fixed.
+L<[perl #126152]|https://rt.perl.org/Ticket/Display.html?id=126152>
=back
=head1 Platform Support
-XXX Any changes to platform support should be listed in the sections below.
+=head2 Platform-Specific Notes
-[ Within the sections, list each platform as a =item entry with specific
-changes as paragraphs below it. ]
+=over 4
-=head2 New Platforms
+=item IRIX
-XXX List any platforms that this version of perl compiles on, that previous
-versions did not. These will either be enabled by new files in the F<hints/>
-directories, or new subdirectories and F<README> files at the top level of the
-source tree.
+=over
-=over 4
+=item *
+
+Under some circumstances IRIX stdio fgetc() and fread() set the errno to
+C<ENOENT>, which made no sense according to either IRIX or POSIX docs. Errno
+is now cleared in such cases.
+L<[perl #123977]|https://rt.perl.org/Ticket/Display.html?id=123977>
-=item XXX-some-platform
+=item *
-XXX
+Problems when multiplying long doubles by infinity have been fixed.
+L<[perl #126396]|https://rt.perl.org/Ticket/Display.html?id=126396>
=back
-=head2 Discontinued Platforms
+=item MacOS X
+
+=over
+
+=item *
-XXX List any platforms that this version of perl no longer compiles on.
+Until now OS X builds of perl have specified a link target of 10.3 (Panther,
+2003) but have not specified a compiler target. From now on, builds of perl on
+OS X 10.6 or later (Snow Leopard, 2008) by default capture the current OS X
+version and specify that as the explicit build target in both compiler and
+linker flags, thus preserving binary compatibility for extensions built later
+regardless of changes in OS X, SDK, or compiler and linker versions. To
+override the default value used in the build and preserved in the flags,
+specify C<export MACOSX_DEPLOYMENT_TARGET=10.N> before configuring and building
+perl, where 10.N is the version of OS X you wish to target. In OS X 10.5 or
+earlier there is no change to the behavior present when those systems were
+current; the link target is still OS X 10.3 and there is no explicit compiler
+target.
-=over 4
+=back
+
+=item VMS
+
+=over
-=item XXX-some-platform
+=item *
+
+Perl now implements its own C<killpg> by scanning for processes in the
+specified process group, which may not mean exactly the same thing as a Unix
+process group, but allows us to send a signal to a parent (or master) process
+and all of its sub-processes. At the perl level, this means we can now send a
+negative pid like so:
+
+ kill SIGKILL, -$pid;
-XXX
+to signal all processes in the same group as C<$pid>.
=back
-=head2 Platform-Specific Notes
+=item Win32
-XXX List any changes for specific platforms. This could include configuration
-and compilation changes or changes in portability/compatibility. However,
-changes within modules for platforms should generally be listed in the
-L</Modules and Pragmata> section.
+=over
-=over 4
+=item *
-=item XXX-some-platform
+A new build option C<USE_NO_REGISTRY> has been added to the makefiles. This
+option is off by default, meaning the default is to do Windows registry
+lookups. This option stops Perl from looking inside the registry for anything.
+For what values are looked up in the registry see L<perlwin32>. Internally, in
+C, the name of this option is C<WIN32_NO_REGISTRY>.
+
+=item *
-XXX
+The behavior of Perl using C<HKEY_CURRENT_USER\Software\Perl> and
+C<HKEY_LOCAL_MACHINE\Software\Perl> to lookup certain values, including C<%ENV>
+vars starting with C<PERL> has changed. Previously, the 2 keys were checked
+for entries at all times through Perl processes life time even if they did not
+exist. For performance reasons, now, if the root key (i.e.
+C<HKEY_CURRENT_USER\Software\Perl> or C<HKEY_LOCAL_MACHINE\Software\Perl>) does
+not exist at process start time, it will not be checked again for C<%ENV>
+override entries for the remainder of the Perl processes life. This more
+closely matches Unix behaviour in that the environment is copied or inherited
+on startup and changing the variable in the parent process or another process
+or editing F<.bashrc> will not change the environmental variable in other
+existing, running, processes.
+
+=item *
+
+One glob fetch was removed for each C<-X> or C<stat> call whether done from
+Perl code or internally from Perl's C code. The glob being looked up was
+C<${^WIN32_SLOPPY_STAT}> which is a special variable. This makes C<-X> and
+C<stat> slightly faster.
+
+=item *
+
+During miniperl's process startup, during the build process, 4 to 8 IO calls
+related to the process starting F<.pl> and the F<buildcustomize.pl> file were
+removed from the code opening and executing the first 1 or 2 F<.pl> files.
+
+=back
=back
=head1 Internal Changes
-XXX Changes which affect the interface available to C<XS> code go here. Other
-significant internal changes for future core maintainers should be noted as
-well.
+=over 4
-[ List each change as a =item entry ]
+=item *
-=over 4
+L<perlapi/sv_backoff> had its return type changed from C<int> to C<void>. It
+previously has always returned C<0> since Perl 5.000 stable but that was
+undocumented. Although C<sv_backoff> is marked as public API, XS code is not
+expected to be impacted since the proper API call would be through public API
+C<sv_setsv(sv, &PL_sv_undef)>, or quasi-public C<SvOOK_off>, or non-public
+C<SvOK_off> calls, and the return value of C<sv_backoff> was previously a
+meaningless constant that can be rewritten as C<(sv_backoff(sv),0)>.
=item *
-XXX
+The C<EXTEND> and C<MEXTEND> macros have been improved to avoid various issues
+with integer truncation and wrapping. In particular, some casts formerly used
+within the macros have been removed. This means for example that passing an
+unsigned nitems argument is likely to raise a compiler warning now (it's always
+been documented to require a signed value; formerly int, lately SSize_t).
=back
=head1 Selected Bug Fixes
-XXX Important bug fixes in the core language are summarized here. Bug fixes in
-files in F<ext/> and F<lib/> are best summarized in L</Modules and Pragmata>.
+=over 4
-[ List each fix as a =item entry ]
+=item *
-=over 4
+There were places in regular expression patterns where comments (C<(?#...)>)
+weren't allowed, but should have been. This is now fixed.
+L<[perl #116639]|https://rt.perl.org/Ticket/Display.html?id=116639>
=item *
-XXX
+A regression from Perl 5.20 has been fixed, in which some syntax errors in
+L<C<(?[...])>|perlrecharclass/Extended Bracketed Character Classes> constructs
+within regular expression patterns could cause a segfault instead of a proper
+error message.
+L<[perl #126180]|https://rt.perl.org/Ticket/Display.html?id=126180>
-=back
+=item *
-=head1 Known Problems
+Some problems with attempting to extend the perl stack to around 2G or 4G
+entries have been fixed. This was particularly an issue on 32-bit perls built
+to use 64-bit integers, and was easily noticeable with the list repetition
+operator, e.g.
-XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
-tests that had to be C<TODO>ed for the release would be noted here. Unfixed
-platform specific bugs also go here.
+ @a = (1) x $big_number
-[ List each fix as a =item entry ]
+Formerly perl may have crashed, depending on the exact value of C<$big_number>;
+now it will typically raise an exception.
+L<[perl #125937]|https://rt.perl.org/Ticket/Display.html?id=125937>
-=over 4
+=item *
+
+In a regex conditional expression C<(?(condition)yes-pattern|no-pattern)>, if
+the condition is C<(?!)> then perl failed the match outright instead of
+matching the no-pattern. This has been fixed.
+L<[perl #126222]|https://rt.perl.org/Ticket/Display.html?id=126222>
+
+=item *
+
+The special backtracking control verbs C<(*VERB:ARG)> now all allow an optional
+argument and set C<REGERROR>/C<REGMARK> appropriately as well.
+L<[perl #126186]|https://rt.perl.org/Ticket/Display.html?id=126186>
=item *
-XXX
+Several bugs, including a segmentation fault, have been fixed with the bounds
+checking constructs (introduced in Perl 5.22) C<\b{gcb}>, C<\b{sb}>, C<\b{wb}>,
+C<\B{gcb}>, C<\B{sb}>, and C<\B{wb}>. All the C<\B{}> ones now match an empty
+string; none of the C<\b{}> ones do.
+L<[perl #126319]|https://rt.perl.org/Ticket/Display.html?id=126319>
=back
=item *
-XXX Add anything here that we forgot to add, or were mistaken about, in
-the perldelta of a previous release.
+(This was actually done in Perl 5.23.2, but the perldelta entry got missed.)
+The way that C<OP_AASSIGN> handles assignment with potentially common values
+(e.g. C<($a,$b) = ($b, $a)> has changed. In particular the C<OPpASSIGN_COMMON>
+flag has been replaced with three more specific flags:
-=back
+ OPpASSIGN_COMMON_AGG
+ OPpASSIGN_COMMON_RC1
+ OPpASSIGN_COMMON_SCALAR
-=head1 Obituary
+and the runtime now sometimes does a mark and sweep using the C<SVf_BREAK> to
+detect common elements.
-XXX If any significant core contributor has died, we've added a short obituary
-here.
+=back
=head1 Acknowledgements
XXX Generate this with:
- perl Porting/acknowledgements.pl v5.23.1..HEAD
+ perl Porting/acknowledgements.pl v5.23.3..HEAD
=head1 Reporting Bugs
https://perl5.git.perl.org / perl5.git / blobdiff