=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 v5.23.5
+perldelta - what is new for perl v5.23.8
=head1 DESCRIPTION
-This document describes differences between the 5.23.4 release and the 5.23.5
+This document describes differences between the 5.23.7 release and the 5.23.8
release.
-If you are upgrading from an earlier release such as 5.23.3, first read
-L<perl5234delta>, which describes differences between 5.23.3 and 5.23.4.
-
-=head1 Notice
-
-XXX Any important notices here
+If you are upgrading from an earlier release such as 5.23.6, first read
+L<perl5237delta>, which describes differences between 5.23.6 and 5.23.7.
=head1 Core Enhancements
-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 More fields provided to C<sigaction> callback with C<SA_SIGINFO>
-[ List each enhancement as a =head2 entry ]
+When passing the C<SA_SIGINFO> flag to L<sigaction|POSIX/sigaction>, the
+C<errno>, C<status>, C<uid>, C<pid>, C<addr> and C<band> fields are now
+included in the hash passed to the handler, if supported by the
+platform.
=head1 Security
-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.
+=head2 Set proper umask before calling C<mkstemp(3)>
+
+In 5.22 perl started setting umask to 0600 before calling C<mkstemp(3)>
+and restoring it afterwards. This wrongfully tells open(2) to strip
+the owner read and write bits from the given mode before applying it,
+rather than the intended negation of leaving only those bits in place.
+
+Systems that use mode 0666 in C<mkstemp(3)> (like old versions of
+glibc) createa a file with permissions 0066, leaving world read and
+write permissions regardless of current umask.
-[ List each security issue as a =head2 entry ]
+This has been fixed by using umask 0177 instead. [perl #127322]
=head1 Incompatible Changes
-XXX For a release on a stable branch, this section aspires to be:
+=head2 C<qr/\N{}/> now disallowed under C<use re "strict">
- 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.
+An empty C<\N{}> makes no sense, but for backwards compatibility is
+silently accepted as doing nothing. But now this is a fatal error under
+the experimental feature L<re/'strict' mode>.
-[ List each incompatible change as a =head2 entry ]
+=head1 Performance Enhancements
-=head1 Deprecations
+=over 4
-XXX Any deprecated features, syntax, modules etc. should be listed here.
+=item *
-=head2 Module removals
+The overhead of scope entry and exit has been considerably reduced, so
+for example subroutine calls, loops and basic blocks are all faster now.
+This empty function call now takes about a third less time to execute:
-XXX Remove this section if inapplicable.
+ sub f{} f();
-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.
+On Win32, C<stat>ing or C<-X>ing a path, if the file or directory does not
+exist, is now 3.5x faster on a SSD (or any drive) than before.
-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.
+=back
-=over
+=head1 Modules and Pragmata
-=item XXX
+=head2 Updated Modules and Pragmata
-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.
+=over 4
-=back
+=item *
-[ List each other deprecation as a =head2 entry ]
+F<cpan/podlators/> has been upgraded from version 4.04 to 4.06.
-=head1 Performance Enhancements
+=item *
+
+The PathTools module collection has been upgraded from version 3.62
+to 3.63.
-XXX Changes which enhance performance without changing behaviour go here.
-There may well be none in a stable release.
+=item *
-[ List each enhancement as a =item entry ]
+L<DynaLoader> has been upgraded from version 1.37 to 1.38.
-=over 4
+DynaLoader now always looks for bootstrap files having the same base name as
+the module for which the bootstrap code is being run. Previously, and only on
+platforms that use C<mod2fname> to produce unique loadable library names,
+L<DynaLoader> would look for the bootstrap file using a base name that matched
+the loadable library and not find it.
=item *
-XXX
+L<Encode> has been upgraded from version 2.78 to 2.80.
-=back
+=item *
-=head1 Modules and Pragmata
+L<ExtUtils::CBuilder> has been upgraded from version 0.280224 to 0.280225.
-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::MakeMaker> has been upgraded from version 7.10 to 7.10_01.
-=head2 New Modules and Pragmata
+=item *
-=over 4
+L<File::Spec> has been upgraded from version 3.62 to 3.63.
=item *
-XXX
+L<IPC::SysV> has been upgraded from version 2.04 to 2.05.
-=back
+=item *
-=head2 Updated Modules and Pragmata
+L<Module::CoreList> has been upgraded from version 5.20160120 to 5.20160121.
-=over 4
+=item *
+
+L<ODBM_File> has been upgraded from version 1.12 to 1.13.
=item *
-L<XXX> has been upgraded from version A.xx to B.yy.
+L<PerlIO::encoding> has been upgraded from version 0.23 to 0.24.
-=back
+=item *
-=head2 Removed Modules and Pragmata
+L<POSIX> has been upgraded from version 1.59 to 1.63.
-=over 4
+It can now export constants for the C<code> value in the hash passed to the
+L<sigaction|POSIX/sigaction> handler when using the C<SA_SIGINFO> flag.
+
+These previously deprecated functions are now removed: C<isalnum>,
+C<isalpha>, C<iscntrl>, C<isdigit>, C<isgraph>, C<islower>, C<isprint>,
+C<ispunct>, C<isspace>, C<isupper>, and C<isxdigit>.
=item *
-XXX
+L<Storable> has been upgraded from version 2.54 to 2.55.
+
+=item *
+
+L<Time::HiRes> has been upgraded from version 1.9728 to 1.9730.
+
+It can now export Linux-specific and FreeBSD-specific C<clock_gettime()>
+constants. It also now has emulation for OS X C<clock_nanosleep()>,
+C<clock_gettime()>, and C<clock_getres()>.
=back
=head1 Documentation
-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>.
-
-=head2 New Documentation
+=head2 Changes to Existing Documentation
-XXX Changes which create B<new> files in F<pod/> go here.
+=head3 L<perlguts>
-=head3 L<XXX>
+=over 4
-XXX Description of the purpose of the new file here
+=item *
-=head2 Changes to Existing Documentation
+A new section has been added, L<perlguts/"Dynamic Scope and the Context
+Stack">, which explains how the perl context stack works.
-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.
+=back
-=head3 L<XXX>
+=head3 L<perlmodlib>
=over 4
=item *
-XXX Description of the change here
+We now recommend contacting the module-authors list or PAUSE in seeking
+guidance on the naming of modules.
=back
including warnings and fatal error messages. For the complete list of
diagnostic messages, see L<perldiag>.
-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.
-
=head2 New Diagnostics
-XXX Newly added diagnostic messages go under here, separated into New Errors
-and New Warnings
-
=head3 New Errors
=over 4
=item *
-XXX L<message|perldiag/"message">
+L<Sequence (?PE<lt>... not terminated in regex; marked by S<<-- HERE> in mE<sol>%sE<sol>
+|perldiag/"Sequence (?PE<lt>... not terminated in regex; marked by <-- HERE in mE<sol>%sE<sol>">
+
+=item *
+
+L<Sequence (?PE<gt>... not terminated in regex; marked by S<<-- HERE> in mE<sol>%sE<sol>
+|perldiag/Sequence (?PE<gt>... not terminated in regex; marked by <-- HERE in mE<sol>%sE<sol>>
+
+=item *
+
+L<Empty \%c in regex; marked by S<<-- HERE> in mE<sol>%sE<sol>
+|perldiag/Empty \%c in regex; marked by <-- HERE in mE<sol>%sE<sol>>
=back
=item *
-XXX L<message|perldiag/"message">
+L<Assuming NOT a POSIX class since %s in regex; marked by E<lt>-- HERE in mE<sol>%sE<sol>|
+perldiag/Assuming NOT a POSIX class since %s in regex; marked by <-- HERE in mE<sol>%sE<sol>>
=back
-=head2 Changes to Existing Diagnostics
-
-XXX Changes (i.e. rewording) of diagnostic messages go here
+=head1 Configuration and Compilation
=over 4
=item *
-XXX Describe change here
+The GNU Make makefile for Win32 now supports parallel builds. [perl #126632]
-=back
+=item *
+
+You can now build perl with MSVC++ on Win32 using GNU Make. [perl #126632]
+
+=item *
-=head1 Utility Changes
+Bison 3.0 is now supported.
-XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go here.
-Most of these are built within the directory F<utils>.
+=back
-[ 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. ]
+=head1 Platform Support
-=head2 L<XXX>
+=head2 Platform-Specific Notes
=over 4
+=item VMS
+
+=over
+
=item *
-XXX
+For those C<%ENV> elements based on the CRTL environ array, we've always
+preserved case when setting them but did look-ups only after upcasing the
+key first, which made lower- or mixed-case entries go missing. This problem
+has been corrected by making C<%ENV> elements derived from the environ array
+case-sensitive on look-up as well as case-preserving on store.
-=back
+=item *
-=head1 Configuration and Compilation
+Environment look-ups for C<PERL5LIB> and C<PERLLIB> previously only
+considered logical names, but now consider all sources of C<%ENV> as
+determined by C<PERL_ENV_TABLES> and as documented in L<perlvms/%ENV>.
+
+=back
-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.
+=back
-[ List changes as a =item entry ].
+=head2 Platform-Specific Notes
=over 4
-=item *
+=item Win32
-C<Configure> now acts as if the C<-O> option is always passed, allowing command
-line options to override saved configuration. This should eliminate confusion
-when command line options are ignored for no obvious reason. C<-O> is now
-permitted, but ignored.
+Builds using Microsoft Visual C++ 2003 and earlier no longer produce
+an "INTERNAL COMPILER ERROR" message. [perl #126045]
=back
-=head1 Testing
+=head1 Internal Changes
+
+=over 4
-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.
+=item *
-[ List each test improvement as a =item entry ]
+The implementation of perl's context stack system, and its internal API,
+have been heavily reworked. Note that no significant changes have been
+made to any external APIs, but XS code which relies on such internal
+details may need to be fixed. The main changes are:
=over 4
=item *
-XXX
-
-=back
+The C<PUSHBLOCK()>, C<POPSUB()> etc. macros have been replaced with static
+inline functions such as C<cx_pushblock()>, C<cx_popsub()> etc. These use
+function args rather than implicitly relying on local vars such as
+C<gimme> and C<newsp> being available. Also their functionality has
+changed: in particular, C<cx_popblock()> no longer decrements
+C<cxstack_ix>. The ordering of the steps in the C<pp_leave*> functions
+involving C<cx_popblock()>, C<cx_popsub()> etc. has changed. See the new
+documentation, L<perlguts/"Dynamic Scope and the Context Stack">, for
+details on how to use them.
-=head1 Platform Support
+=item *
-XXX Any changes to platform support should be listed in the sections below.
+Various macros, which now consistently have a CX_ prefix, have been added:
-[ Within the sections, list each platform as a =item entry with specific
-changes as paragraphs below it. ]
+ CX_CUR(), CX_LEAVE_SCOPE(), CX_POP()
-=head2 New Platforms
+or renamed:
-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.
+ CX_POP_SAVEARRAY(), CX_DEBUG(), CX_PUSHSUBST(), CX_POPSUBST()
-=over 4
+=item *
-=item XXX-some-platform
+C<cx_pushblock()> now saves C<PL_savestack_ix> and C<PL_tmps_floor>, so
+CMpp_enter*> and C<pp_leave*> no longer do
-XXX
+ ENTER; SAVETMPS; ....; LEAVE
-=back
+=item *
-=head2 Discontinued Platforms
+C<cx_popblock()> now also restores C<PL_curpm>.
-XXX List any platforms that this version of perl no longer compiles on.
+=item *
-=over 4
+In C<dounwind()> for every context type, the current savestack frame is
+now processed before each context is popped; formerly this was only done
+for sub-like context frames. This action has been removed from
+C<cx_popsub()> and placed into its own macro, C<CX_LEAVE_SCOPE(cx)>, which
+must be called before C<cx_popsub()> etc.
-=item XXX-some-platform
+C<dounwind()> now also does a C<cx_popblock()> on the last popped frame
+(formerly it only did the C<cx_popsub()> etc. actions on each frame).
-XXX
+=item *
-=back
+The temps stack is now freed on scope exit; previously, temps created
+during the last statement of a block wouldn't be freed until the next
+C<nextstate> following the block (apart from an existing hack that did
+this for recursive subs in scalar context); and in something like
+C<f(g())>, the temps created by the last statement in C<g()> would
+formerly not be freed until the statement following the return from
+C<f()>.
-=head2 Platform-Specific Notes
+=item *
-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.
+Most values that were saved on the savestack on scope entry are now
+saved in suitable new fields in the context struct, and saved and
+restored directly by C<cx_pushfoo()> and C<cx_popfoo()>, which is much
+faster.
-=over 4
+=item *
-=item XXX-some-platform
+Various context struct fields have been added, removed or modified.
-XXX
+=item *
-=back
+The handling of C<@_> in C<cx_pushsub()> and C<cx_popsub()> has been
+considerably tidied up, including removing the C<argarray> field from the
+context struct, and extracting out some common (but rarely used) code into
+a separate function, C<clear_defarray()>. Also, useful subsets of
+C<cx_popsub()> which had been unrolled in places like C<pp_goto> have been
+gathered into the new functions C<cx_popsub_args()> and
+C<cx_popsub_common()>.
-=head1 Internal Changes
+=item *
-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.
+C<pp_leavesub> and C<pp_leavesublv> now use the same function as the rest
+of the C<pp_leave*>'s to process return args.
-[ List each change as a =item entry ]
+=item *
-=over 4
+C<CXp_FOR_PAD> and C<CXp_FOR_GV> flags have been added, and
+C<CXt_LOOP_FOR> has been split into C<CXt_LOOP_LIST>, C<CXt_LOOP_ARY>.
=item *
-XXX
+Some variables formerly declared by C<dMULTICALL> (but not documented) have
+been removed.
+
+=back
=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
+Line numbers larger than 2**31-1 but less than 2**32 are no longer
+returned by caller() as negative numbers. [perl #126991]
=item *
-C<\b{sb}> works much better. In Perl v5.22.0, this new construct didn't
-seem to give the expected results, yet passed all the tests in the
-extensive suite furnished by Unicode. It turns out that it was because
-these were short input strings, and the failures had to do with longer
-inputs. This was fixed in Perl 5.23.4, but the improvement was not
-noticed until after that was released, so is included here now.
+C<< unless ( I<assignment> ) >> now properly warns when syntax
+warnings are enabled. [perl #127122]
=item *
-Certain syntax errors in
-L<perlrecharclass/Extended Bracketed Character Classes> caused panics
-instead of the proper error message. This has now been fixed. [perl
-#126481]
+Setting an C<ISA> glob to an array reference now properly adds
+C<isaelem> magic to any existing elements. Previously modifying such
+an element would not update the ISA cache, so method calls would call
+the wrong function. Perl would also crash if the C<ISA> glob was
+destroyed, since new code added in 5.23.7 would try to release the
+C<isaelem> magic from the elements. [perl #127351]
-=back
+=item *
-=head1 Known Problems
+If a here-doc was found while parsing another operator, the parser had
+already read end of file, and the here-doc was not terminated, perl
+could produce an assertion or a segmentation fault. This now reliably
+complains about the unterminated here-doc. [perl #125540]
-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.
+=item *
-[ List each fix as a =item entry ]
+untie() would sometimes return the last value returned by the UNTIE()
+handler as well as it's normal value, messing up the stack. [perl
+#126621]
-=over 4
+=item *
+
+Fixed an operator precedence problem when C< castflags & 2> is true.
+[perl #127474]
=item *
-XXX
+Caching of DESTROY methods could result in a non-pointer or a
+non-STASH stored in the SvSTASH() slot of a stash, breaking the B
+STASH() method. The DESTROY method is now cached in the MRO metadata
+for the stash. [perl #126410]
-=back
+=item *
-=head1 Errata From Previous Releases
+The AUTOLOAD method is now called when searching for a DESTROY method,
+and correctly sets C<$AUTOLOAD> too. [perl #124387] [perl #127494]
-=over 4
+=item *
+
+Avoid parsing beyond the end of the buffer when processing a C<#line>
+directive with no filename. [perl #127334]
=item *
-XXX Add anything here that we forgot to add, or were mistaken about, in
-the perldelta of a previous release.
+Perl now raises a warning when a regular expression pattern looks like
+it was supposed to contain a POSIX class, like C<qr/[[:alpha:]]/>, but
+there was some slight defect in its specification which causes it to
+instead be treated as a regular bracketed character class. An example
+would be missing the second colon in the above like this:
+C<qr/[[:alpha]]/>. This compiles to match a sequence of two characters.
+The second is C<"]">, and the first is any of: C<"[">, C<":">, C<"a">,
+C<"h">, C<"l">, or C<"p">. This is unlikely to be the intended
+meaning, and now a warning is raised. No warning is raised unless the
+specification is very close to one of the 14 legal POSIX classes. (See
+L<perlrecharclass/POSIX Character Classes>.)
+[perl #8904]
-=back
+=item *
+
+Certain regex patterns involving a complemented POSIX class in an
+inverted bracketed character class, and matching something else
+optionally would improperly fail to match. An example of one that could
+fail is C</qr/_?[^\Wbar]\x{100}/>. This has been fixed.
+[perl #127537]
-=head1 Obituary
+=item *
+
+Perl 5.22 added support to the C99 hexadecimal floating point notation,
+but sometimes misparses hex floats. This had been fixed.
+[perl #127183]
-XXX If any significant core contributor has died, we've added a short obituary
-here.
+=back
=head1 Acknowledgements
-XXX Generate this with:
+Perl 5.23.8 represents approximately 4 weeks of development since Perl 5.23.7
+and contains approximately 30,000 lines of changes across 350 files from 23
+authors.
+
+Excluding auto-generated files, documentation and release tools, there were
+approximately 14,000 lines of changes to 210 .pm, .t, .c and .h files.
+
+Perl continues to flourish into its third decade thanks to a vibrant community
+of users and developers. The following people are known to have contributed the
+improvements that became Perl 5.23.8:
+
+Aaron Crane, Chris 'BinGOs' Williams, Craig A. Berry, Dagfinn Ilmari
+Mannsåker, Daniel Dragan, David Mitchell, Ed J, Herbert Breunung, H.Merijn
+Brand, James E Keenan, Jarkko Hietaniemi, Karl Williamson, Lukas Mai, Niko
+Tyni, Pip Cet, Ricardo Signes, Sawyer X, Sisyphus, Stevan Little, Steve Hay,
+Todd Rinaldo, Tom Hukins, Tony Cook.
+
+The list above is almost certainly incomplete as it is automatically generated
+from version control history. In particular, it does not include the names of
+the (very much appreciated) contributors who reported issues to the Perl bug
+tracker.
+
+Many of the changes included in this version originated in the CPAN modules
+included in Perl's core. We're grateful to the entire CPAN community for
+helping Perl to flourish.
- perl Porting/acknowledgements.pl v5.23.4..HEAD
+For a more complete list of all of Perl's historical contributors, please see
+the F<AUTHORS> file in the Perl source distribution.
=head1 Reporting Bugs