=head1 NAME
-perldelta - what is new for perl v5.38.0
+perldelta - what is new for perl v5.39.7
=head1 DESCRIPTION
-This document describes differences between the 5.36.0 release and the 5.38.0
+This document describes differences between the 5.39.6 release and the 5.39.7
release.
-=head1 Core Enhancements
+If you are upgrading from an earlier release such as 5.39.5, first read
+L<perl5396delta>, which describes differences between 5.39.5 and 5.39.6.
-=head2 New C<class> Feature
-
-A new B<experimental> syntax is now available for defining object classes,
-where per-instance data is stored in "field" variables that behave like
-lexicals.
-
- use feature 'class';
-
- class Point
- {
- field $x;
- field $y;
-
- method zero { $x = $y = 0; }
- }
-
-This is described in more detail in L<perlclass>. Notes on the internals of
-its implementation and other related details can be found in L<perlclassguts>.
-
-This remains a new and experimental feature, and is very much still under
-development. It will be the subject of much further addition, refinement and
-alteration in future releases. As it is experimental, it yields warnings in
-the C<experimental::class> category. These can be silenced by a
-C<no warnings> statement.
-
- use feature 'class';
- no warnings 'experimental::class';
-
-=head2 Unicode 15.0 is supported
-
-See L<https://www.unicode.org/versions/Unicode15.0.0/> for details.
-
-=head2 Deprecation warnings now have specific subcategories
-
-All deprecation warnings now have their own specific deprecation category which
-can be disabled individually. You can see a list of all deprecated features in
-L<perldeprecation>, and in L<warnings>. The following list is from L<warnings>:
-
- +- deprecated ----+
- | |
- | +- deprecated::apostrophe_as_package_separator
- | |
- | +- deprecated::delimiter_will_be_paired
- | |
- | +- deprecated::dot_in_inc
- | |
- | +- deprecated::goto_construct
- | |
- | +- deprecated::smartmatch
- | |
- | +- deprecated::unicode_property_name
- | |
- | +- deprecated::version_downgrade
-
-It is still possible to disable all deprecation warnings in a single
-statement with
-
- no warnings 'deprecated';
-
-but now is possible to have a finer grained control. As has historically been
-the case these warnings are automatically enabled with
-
- use warnings;
-
-=head2 %{^HOOK} API introduced
-
-For various reasons it can be difficult to create subroutine wrappers
-for some of perls keywords. Any keyword which has an undefined
-prototype simply cannot be wrapped with a subroutine, and some keywords
-which perl permits to be wrapped are in practice very tricky to wrap.
-For example C<require> is tricky to wrap, it is possible but doing so
-changes the stack depth, and the standard methods of exporting assume
-that they will be exporting to a package at certain stack depth up the
-stack, and the wrapper will thus change where functions are exported to
-unless implemented with a great deal of care. This can be very awkward
-to deal with.
-
-Accordingly we have introduced a new hash called C<%{^HOOK}> which is
-intended to facilitate such cases. When a keyword supports any kind of
-special hook then the hook will live in this new hash. Hooks in this
-hash will be named after the function they are called by, followed by
-two underbars and then the phase they are executed in, currently either
-before or after the keyword is executed.
-
-In this initial release we support two hooks C<require__before> and
-C<require__after>. These are provided to make it easier to perform tasks
-before and after a require statement.
-
-See L<perlvar> for more details.
-
-=head2 PERL_RAND_SEED
-
-Added a new environment variable C<PERL_RAND_SEED> which can be used to
-cause a perl program which uses C<rand> without using C<srand()>
-explicitly or which uses C<srand()> with no arguments to be repeatable.
-See L<perlrun>. This feature can be disabled at compile time by passing
-
- -Accflags=-DNO_PERL_RAND_SEED
-
-to F<Configure> during the build process.
-
-=head2 Defined-or and logical-or assignment default expressions in signatures
-
-The default expression for a subroutine signature parameter can now be
-assigned using the C<//=> or C<||=> operators, to apply the defaults whenever
-the caller provided an undefined or false value (respectively), rather than
-simply when the parameter is missing entirely. For more detail see the
-documentation in L<perlsub>.
-
-=head2 @INC Hook Enhancements and $INC and INCDIR
-
-The internals for C<@INC> hooks have been hardened to handle various
-edge cases and should no longer segfault or throw assert failures when
-hooks modify C<@INC> during a require operation. As part of this we
-now ensure that any given hook is executed at most once during a require
-call, and that any duplicate directories do not trigger additional
-directory probes.
-
-To provide developers more control over dynamic module lookup, a new hook
-method C<INCDIR> is now supported. An object supporting this method may be
-injected into the C<@INC> array, and when it is encountered in the module
-search process it will be executed, just like how INC hooks are executed,
-and its return value used as a list of directories to search for the
-module. Returning an empty list acts as a no-op. Note that since any
-references returned by this hook will be stringified and used as strings,
-you may not return a hook to be executed later via this API.
-
-When an C<@INC> hook (either C<INC> or C<INCDIR>) is called during
-require, the C<$INC> variable will be localized to be the value of the
-index of C<@INC> that the hook came from. If the hook wishes to override
-what the "next" index in C<@INC> should be it may update C<$INC> to be one
-less than the desired index (C<undef> is equivalent to C<-1>). This
-allows an C<@INC> hook to completely rewrite the C<@INC> array and have
-perl restart its directory probes from the beginning of C<@INC>.
-
-Blessed CODE references in C<@INC> that do not support the C<INC> or
-C<INCDIR> methods will no longer trigger an exception, and instead will
-be treated the same as unblessed coderefs are, and executed as though
-they were an C<INC> hook.
-
-=head2 Forbidden control flow out of C<defer> or C<finally> now detected at compile-time
-
-It is forbidden to attempt to leave a C<defer> or C<finally> block by means
-of control flow such as C<return> or C<goto>. Previous versions of perl could
-only detect this when actually attempted at runtime.
-
-This version of perl adds compile-time detection for many cases that can be
-statically determined. This may mean that code which compiled successfully on
-a previous version of perl is now reported as a compile-time error with this
-one. This only happens in cases where it would have been an error to actually
-execute the code anyway; the error simply happens at an earlier time.
-
-=head2 Optimistic Eval in Patterns
-
-The use of C<(?{ ... })> and C<(??{ ... })> in a pattern disables various
-optimisations globally in that pattern. This may or may not be desired by the
-programmer. This release adds the C<(*{ ... })>
-equivalent. The only difference is that it does not and will never disable
-any optimisations in the regex engine. This may make it more unstable in the
-sense that it may be called more or less times in the future, however the
-number of times it executes will truly match how the regex engine functions.
-For example, certain types of optimisation are disabled when C<(?{ ... })> is
-included in a pattern, so that patterns which are O(N) in normal use become
-O(N*N) with a C<(?{ ... })> pattern in them. Switching to C<(*{ ... })> means
-the pattern will stay O(N).
-
-=head2 REG_INF has been raised from 65,536 to 2,147,483,647
-
-Many regex quantifiers used to be limited to U16_MAX in the past, but are
-now limited to I32_MAX, thus it is now possible to write /(?:word){1000000}/
-for example. Note that doing so may cause the regex engine to run longer
-and use more memory.
-
-=head2 New API functions optimize_optree and finalize_optree
-
-There are two new API functions for operating on optree fragments, ensuring
-you can invoke the required parts of the optree-generation process that might
-otherwise not get invoked (e.g. when creating a custom LOGOP). To get access
-to these functions, you first need to set a C<#define> to opt-in to using
-these functions.
-
- #define PERL_USE_VOLATILE_API
-
-These functions are closely tied to the internals of how the interpreter
-works, and could be altered or removed at any time if other internal changes
-make that necessary.
-
-=head2 Some C<goto>s are now permitted in C<defer> and C<finally> blocks
-
-Perl version 5.36.0 added C<defer> blocks and permitted the C<finally> keyword
-to also add similar behaviour to C<try>/C<catch> syntax. These did not permit
-any C<goto> expression within the body, as it could have caused control flow
-to jump out of the block. Now, some C<goto> expressions are allowed, if they
-have a constant target label, and that label is found within the block.
-
- use feature 'defer';
-
- defer {
- goto LABEL;
- print "This does not execute\n";
- LABEL: print "This does\n";
- }
-
-=head2 New regexp variable ${^LAST_SUCCESSFUL_PATTERN}
-
-This allows access to the last succesful pattern that matched in the current
-scope. Many aspects of the regex engine refer to the "last successful
-pattern". The empty pattern reuses it, and all of the magic regex vars relate
-to it. This allows access to its pattern. The following code
-
- if (m/foo/ || m/bar/) {
- s//PQR/;
- }
-
-can be rewritten as follows
-
- if (m/foo/ || m/bar/) {
- s/${^LAST_SUCCESSFUL_PATTERN}/PQR/;
- }
-
-and it will do the exactly same thing.
-
-=head2 Locale category LC_NAME now supported on participating platforms
-
-On platforms that have the GNU extension C<LC_NAME> category, you may now use
-it as the category parameter to L<POSIX/setlocale> to set and query its locale.
-
-=head1 Incompatible Changes
-
-=head2 readline() no longer clears the stream error and eof flags
-
-C<readline()>, also spelled C<< <> >>, would clear the handle's error
-and eof flags after an error occurred on the stream.
-
-In nearly all cases this clear is no longer done, so the error and
-eof flags now properly reflect the status of the stream after
-readline().
-
-Since the error flag is no longer cleared calling close() on the
-stream may fail and if the stream was not explicitly closed, the
-implicit close of the stream may produce a warning.
-
-This has resulted in two main types of problems in downstream CPAN
-modules, and these may also occur in your code:
-
-=over
-
-=item *
-
-If your code reads to end of file, and then rebinds the handle to a
-new file descriptor, previously since the eof flag wasn't set you
-could continue to read from the stream. You now need to clear the eof
-flag yourself with C<< $handle->clearerr() >> to continue reading.
-
-=item *
-
-If your code encounters an error on the stream while reading with
-readline() you will need to call C<< $handle->clearerr >> to continue
-reading. The one case this occurred the underlying file descriptor was
-marked non-blocking, so the read() system call was failing with
-C<EAGAIN>, which resulted in the error flag being set on the stream.
-
-=back
-
-The only case where error and eof flags continue to cleared on
-error is when reading from the child process for glob() in
-F<miniperl>. This allows it to correctly report errors from the child
-process on close(). This is unlikely to be an issue during normal
-perl development.
-
-[L<GH #20060|https://github.com/Perl/perl5/issues/20060>]
-
-=head2 C<INIT> blocks no longer run after an C<exit()> in C<BEGIN>
-
-C<INIT> blocks will no longer run after an C<exit()> performed inside of
-a C<BEGIN>. This means that the combination of the C<-v> option and the
-C<-c> option no longer executes a compile check as well as showing the
-perl version. The C<-v> option executes an exit(0) after printing the
-version information inside of a C<BEGIN> block, and the C<-c> check is
-implemented by using C<INIT> hooks, resulting in the C<-v> option taking
-precedence.
-
-[L<GH #1537|https://github.com/Perl/perl5/issues/1537>]
-[L<GH #20181|https://github.com/Perl/perl5/issues/20181>]
-
-=head2 Syntax errors will no longer produce "phantom error messages".
-
-Generally perl will continue parsing the source code even after
-encountering a compile error. In many cases this is helpful, for
-instance with misspelled variable names it is helpful to show as many
-examples of the error as possible. But in the case of syntax errors
-continuing often produces bizarre error messages, and may even cause
-segmentation faults during the compile process. In this release the
-compiler will halt at the first syntax error encountered. This means
-that any code expecting to see the specific error messages we used to
-produce will be broken. The error that is emitted will be one of the
-diagnostics that used to be produced, but in some cases some messages
-that used to be produced will no longer be displayed.
-
-See L<Changes to Existing Diagnostics> for more details.
-
-=head2 L<C<utf8::upgrade()>|utf8/Utility functions>
-
-Starting in this release, if the input string is C<undef>, it remains
-C<undef>. Previously it would be changed into a defined, zero-length
-string.
-
-=head2 Changes to "thread-safe" locales
-
-Perl 5.28 introduced "thread-safe" locales on systems that supported
-them, namely modern Windows, and systems supporting POSIX 2008 locale
-operations. These systems accomplish this by having per-thread locales,
-while continuing to support the older global locale operations for code
-that doesn't take the steps necessary to use the newer per-thread ones.
-
-It turns out that some POSIX 2008 platforms have or have had buggy
-implementations, which forced perl to not use them. The
-C<${^SAFE_LOCALES}> scalar variable contains 0 or 1 to indicate whether
-or not the current platform is considered by perl to have a working
-thread-safe implementation. Some implementations have been fixed
-already, but FreeBSD and Cygwin have been newly discovered to be
-sufficiently buggy that the thread-safe operations are no longer used by
-perl, starting in this release. Hence, C<${^SAFE_LOCALES}> is now 0 for
-them. Older versions of perl can be configured to avoid these buggy
-implementations by adding the F<Configure> option
-C<-DNO_POSIX_2008_LOCALE>.
-
-And v5.38 fixes a bug in all previous perls that led to locales not
-being fully thread-safe. The first thread that finishes caused
-the main thread (named C<thread0>) to revert to the global locale in
-effect at startup, discarding whatever the thread's locale had been
-previously set to. If any other thread had switched to the global
-locale by calling C<switch_to_global_locale()> in XS code, those threads
-would all share the global locale, and C<thread0> would not be
-thread-safe.
-
-=head1 Deprecations
-
-=head2 Use of C<'> as a package name separator is deprecated
-
-Using C<'> as package separator in a variable named in a double-quoted
-string has warned since 5.28. It is now deprecated in both string
-interpolation and non-interpolated contexts, and will be removed in
-Perl 5.42.
-
-=head1 Performance Enhancements
-
-=over 4
-
-=item *
-
-Additional optree optimizations for common OP patterns. For example, multiple
-simple OPs replaced by a single streamlined OP, so as to be more efficient at
-runtime. L<[GH #19943]|https://github.com/Perl/perl5/pull/19943>,
-L<[GH #20063]|https://github.com/Perl/perl5/pull/20063>,
-L<[GH #20077]|https://github.com/Perl/perl5/pull/20077>.
-
-=item *
-
-Creating an anonymous sub no longer generates an C<srefgen> op, the
-reference generation is now done in the C<anoncode> or C<anonconst>
-op, saving runtime. [github #20290]
-
-=back
-
-=head1 Modules and Pragmata
-
-=head2 Updated Modules and Pragmata
-
-=over 4
-
-=item *
-
-Added the C<is_tainted()> builtin function. [L<github #19854|https://github.com/Perl/perl5/issues/19854>]
-
-=item *
-
-Added the C<export_lexically()> builtin function as per PPC 0020. [L<github #19895|https://github.com/Perl/perl5/issues/19895>]
-
-=item *
-
-Support for PPC 0018, C<use feature "module_true";> has been added to
-the default feature bundle for v5.38 and later. It may also be used
-explicitly. When enabled inside of a module the module does not need
-to return true explicitly, and in fact the return will be forced to
-a simple true value regardless of what it originally was.
-
-=item *
-
-L<Attribute::Handlers> has been upgraded from version 1.02 to 1.03.
-
-=item *
-
-L<attributes> has been upgraded from version 0.34 to 0.35.
-
-=item *
-
-L<autodie> has been upgraded from version 2.34 to 2.36.
-
-=item *
-
-L<B> has been upgraded from version 1.83 to 1.88.
-
-=item *
-
-L<B::Concise> has been upgraded from version 1.006 to 1.007.
-
-=item *
-
-L<B::Deparse> has been upgraded from version 1.64 to 1.74.
-
-=item *
-
-L<Benchmark> has been upgraded from version 1.23 to 1.24.
-
-=item *
-
-L<bignum> has been upgraded from version 0.65 to 0.66.
-
-=item *
-
-L<Carp> has been upgraded from version 1.52 to 1.54.
-
-=item *
-
-L<Class::Struct> has been upgraded from version 0.66 to 0.68.
-
-=item *
-
-L<Compress::Raw::Bzip2> has been upgraded from version 2.103 to 2.204_001.
-
-=item *
-
-L<Compress::Raw::Zlib> has been upgraded from version 2.105 to 2.204_001.
-
-=item *
-
-L<Config::Perl::V> has been upgraded from version 0.33 to 0.36.
-
-=item *
-
-L<CPAN> has been upgraded from version 2.33 to 2.36.
-
-=item *
-
-L<Data::Dumper> has been upgraded from version 2.184 to 2.188.
-
-=item *
-
-L<DB_File> has been upgraded from version 1.857 to 1.858.
-
-=item *
-
-L<Devel::Peek> has been upgraded from version 1.32 to 1.33.
-
-=item *
-
-L<Devel::PPPort> has been upgraded from version 3.68 to 3.71.
-
-=item *
-
-L<Digest::MD5> has been upgraded from version 2.58 to 2.58_01.
-
-=item *
-
-L<Digest::SHA> has been upgraded from version 6.02 to 6.04.
-
-=item *
-
-L<DynaLoader> has been upgraded from version 1.52 to 1.54.
-
-=item *
-
-L<Encode> has been upgraded from version 3.17 to 3.19.
-
-=item *
-
-L<encoding::warnings> has been upgraded from version 0.13 to 0.14.
-
-=item *
-
-L<Env> has been upgraded from version 1.05 to 1.06.
-
-=item *
-
-L<Errno> has been upgraded from version 1.36 to 1.37.
-
-=item *
-
-L<experimental> has been upgraded from version 0.028 to 0.031.
-
-=item *
-
-L<ExtUtils::CBuilder> has been upgraded from version 0.280236 to 0.280238.
-
-=item *
-
-L<ExtUtils::Install> has been upgraded from version 2.20 to 2.22.
-
-=item *
-
-L<ExtUtils::MakeMaker> has been upgraded from version 7.64 to 7.70.
-
-=item *
-
-L<ExtUtils::Miniperl> has been upgraded from version 1.11 to 1.13.
-
-=item *
-
-L<ExtUtils::ParseXS> has been upgraded from version 3.45 to 3.51.
-
-=item *
-
-L<ExtUtils::PL2Bat> has been upgraded from version 0.004 to 0.005.
-
-=item *
-
-L<ExtUtils::Typemaps> has been upgraded from version 3.45 to 3.51.
-
-=item *
-
-L<feature> has been upgraded from version 1.72 to 1.82.
-
-=item *
-
-L<File::Basename> has been upgraded from version 2.85 to 2.86.
-
-=item *
-
-L<File::Copy> has been upgraded from version 2.39 to 2.41.
-
-=item *
-
-L<File::Find> has been upgraded from version 1.40 to 1.43.
-
-=item *
-
-L<File::Glob> has been upgraded from version 1.37 to 1.40.
-
-=item *
-
-L<File::Spec> has been upgraded from version 3.84 to 3.89.
-
-=item *
-
-L<File::stat> has been upgraded from version 1.12 to 1.13.
-
-=item *
-
-L<FileHandle> has been upgraded from version 2.03 to 2.05.
-
-=item *
-
-L<Filter::Util::Call> has been upgraded from version 1.60 to 1.64.
-
-=item *
-
-L<GDBM_File> has been upgraded from version 1.23 to 1.24.
-
-=item *
-
-L<Getopt::Long> has been upgraded from version 2.52 to 2.54.
-
-=item *
-
-L<Hash::Util> has been upgraded from version 0.28 to 0.30.
-
-=item *
-
-L<HTTP::Tiny> has been upgraded from version 0.080 to 0.083.
-
-=item *
-
-L<I18N::Langinfo> has been upgraded from version 0.21 to 0.22.
-
-=item *
-
-L<IO> has been upgraded from version 1.50 to 1.52.
-
-=item *
-
-IO-Compress has been upgraded from version 2.106 to 2.204.
-
-=item *
-
-L<IO::Zlib> has been upgraded from version 1.11 to 1.14.
-
-=item *
-
-L<JSON::PP> has been upgraded from version 4.07 to 4.16.
-
-=item *
-
-libnet has been upgraded from version 3.14 to 3.15.
-
-=item *
-
-L<Locale::Maketext> has been upgraded from version 1.31 to 1.33.
-
-=item *
-
-L<Math::BigInt> has been upgraded from version 1.999830 to 1.999837.
-
-=item *
-
-L<Math::BigInt::FastCalc> has been upgraded from version 0.5012 to 0.5013.
-
-=item *
-
-L<Math::BigRat> has been upgraded from version 0.2621 to 0.2624.
-
-=item *
-
-L<Math::Complex> has been upgraded from version 1.5902 to 1.62.
-
-=item *
-
-L<Memoize> has been upgraded from version 1.03_01 to 1.16.
-
-=item *
-
-L<MIME::Base64> has been upgraded from version 3.16 to 3.16_01.
-
-=item *
-
-L<Module::CoreList> has been upgraded from version 5.20220520 to 5.20230520.
-
-=item *
-
-L<mro> has been upgraded from version 1.26 to 1.28.
-
-=item *
-
-L<NDBM_File> has been upgraded from version 1.15 to 1.16.
-
-=item *
-
-L<Net::Ping> has been upgraded from version 2.74 to 2.76.
-
-=item *
-
-L<ODBM_File> has been upgraded from version 1.17 to 1.18.
-
-=item *
-
-L<Opcode> has been upgraded from version 1.57 to 1.64.
-
-=item *
-
-L<overload> has been upgraded from version 1.35 to 1.37.
-
-=item *
-
-L<parent> has been upgraded from version 0.238 to 0.241.
-
-=item *
-
-L<PerlIO::via::QuotedPrint> has been upgraded from version 0.09 to 0.10.
-
-=item *
-
-L<Pod::Checker> has been upgraded from version 1.74 to 1.75.
-
-=item *
-
-L<Pod::Html> has been upgraded from version 1.33 to 1.34.
-
-=item *
-
-L<Pod::Usage> has been upgraded from version 2.01 to 2.03.
-
-=item *
-
-L<podlators> has been upgraded from version 4.14 to 5.01.
-
-=item *
-
-L<POSIX> has been upgraded from version 2.03 to 2.13.
-
-=item *
-
-L<re> has been upgraded from version 0.43 to 0.44.
-
-=item *
-
-L<Safe> has been upgraded from version 2.43 to 2.44.
-
-=item *
-
-L<Scalar::Util> has been upgraded from version 1.62 to 1.63.
-
-=item *
-
-L<SDBM_File> has been upgraded from version 1.15 to 1.17.
-
-=item *
-
-L<Socket> has been upgraded from version 2.033 to 2.036.
-
-=item *
-
-L<Storable> has been upgraded from version 3.26 to 3.32.
-
-=item *
-
-L<Sys::Hostname> has been upgraded from version 1.24 to 1.25.
-
-=item *
-
-L<Term::Cap> has been upgraded from version 1.17 to 1.18.
-
-=item *
-
-L<Test::Simple> has been upgraded from version 1.302190 to 1.302194.
-
-=item *
-
-L<Text::Balanced> has been upgraded from version 2.04 to 2.06.
-
-=item *
-
-L<threads> has been upgraded from version 2.27 to 2.36.
-
-=item *
-
-L<threads::shared> has been upgraded from version 1.64 to 1.68.
-
-=item *
-
-L<Tie::File> has been upgraded from version 1.06 to 1.07.
-
-=item *
-
-L<Time::HiRes> has been upgraded from version 1.9770 to 1.9775.
-
-=item *
-
-L<Time::Piece> has been upgraded from version 1.3401 to 1.3401_01.
-
-=item *
-
-L<Unicode::Normalize> has been upgraded from version 1.31 to 1.32.
-
-=item *
-
-L<UNIVERSAL> has been upgraded from version 1.14 to 1.15.
-
-=item *
-
-L<User::grent> has been upgraded from version 1.03 to 1.04.
-
-=item *
-
-L<User::pwent> has been upgraded from version 1.01 to 1.02.
-
-=item *
-
-L<utf8> has been upgraded from version 1.24 to 1.25.
-
-=item *
-
-L<warnings> has been upgraded from version 1.58 to 1.65.
-
-=item *
-
-L<XS::APItest> has been upgraded from version 1.22 to 1.32.
-
-=item *
-
-L<XSLoader> has been upgraded from version 0.31 to 0.32.
-
-=back
-
-=head1 Documentation
-
-=head2 New Documentation
-
-=head3 L<perlclass>
-
-Describes the new C<class> feature.
-
-=head3 L<perlclassguts>
-
-Describes the internals of the new C<class> feature.
-
-=head2 Changes to Existing Documentation
-
-We have attempted to update the documentation to reflect the changes
-listed in this document. If you find any we have missed, open an issue
-at L<https://github.com/Perl/perl5/issues>.
-
-Additionally, the following selected changes have been made:
-
-=head3 L<perlapi>
-
-=over 4
-
-=item *
-
-Documented L<C<hv_ksplit>|perlapi/hv_ksplit>
-
-=item *
-
-Documented L<C<hv_name_set>|perlapi/hv_name_set>
-
-=item *
-
-L<C<hv_store>|perlapi/hv_store> and L<C<hv_stores>|perlapi/hv_stores>
-documentation have been greatly improved.
-
-=item *
-
-Documented L<C<gv_autoload_pv>|perlapi/gv_autoload_pv>
-
-=item *
-
-Documented L<C<gv_autoload_pvn>|perlapi/gv_autoload_pvn>
-
-=item *
-
-Documented L<C<gv_autoload_sv>|perlapi/gv_autoload_sv>
-
-=item *
-
-Documented L<C<gv_name_set>|perlapi/gv_name_set>
-
-=item *
-
-Documented L<C<start_subparse>|perlapi/start_subparse>
-
-=item *
-
-Documented L<C<SV_CHECK_THINKFIRST_COW_DROP>|perlapi/SV_CHECK_THINKFIRST_COW_DROP>
-
-=item *
-
-Documented L<C<SV_CHECK_THINKFIRST>|perlapi/SV_CHECK_THINKFIRST>
-
-=item *
-
-Documented L<C<SvPV_shrink_to_cur>|perlapi/SvPV_shrink_to_cur>
-
-=item *
-
-Documented L<C<save_aelem>|perlapi/save_aelem>
-
-=item *
-
-Documented L<C<save_aelem_flags>|perlapi/save_aelem_flags>
-
-=item *
-
-Documented L<C<save_helem>|perlapi/save_helem>
-
-=item *
-
-Documented L<C<save_helem_flags>|perlapi/save_helem_flags>
-
-=back
-
-=head3 L<perldeprecation>
-
-=over 4
-
-=item *
-
-Added information about unscheduled deprecations and their categories.
-
-=item *
-
-Added category information for existing scheduled deprecations.
-
-=item *
-
-Added smartmatch and apostrophe as a package separator deprecation data.
-
-=back
-
-=head3 L<perlintern>
-
-=over 4
-
-=item *
-
-Documented L<C<save_pushptr>|perlintern/save_pushptr>
-
-=item *
-
-Documented L<C<save_scalar_at>|perlintern/save_scalar_at>
-
-=item *
-
-Entries have been added to L<perlguts> for the new C<newAV_alloc_x>, C<newAV_alloc_xz> and
-C<*_simple> functions.
-
-=item *
-
-References to the now-defunct PrePAN service have been removed from
-L<perlcommunity> and L<perlmodstyle>.
-
-=item *
-
-A section on symbol naming has been added to L<perlhacktips>.
-
-=item *
-
-L<perlexperiment> has been edited to properly reference the warning categories
-for the defer block modifier and extra paired delimiters for quote-like
-operators.
-
-=back
-
-=head3 L<perlexperiment>
-
-=over 4
-
-=item *
-
-Smartmatch has been moved from experimental status to deprecated status.
-Unfortunately the experiment did not work out.
-
-=back
-
-=head3 L<perlfunc>
-
-=over 4
-
-=item *
-
-Some wording improvements have been made for the C<ucfirst>, C<push>,
-C<unshift> and C<bless> functions, as well as additional examples added.
-
-=back
-
-=head3 perlhacktips
-
-=over 4
-
-=item *
-
-A new section, L<perlhacktips/Writing safer macros> has been added to discuss
-pitfalls and solutions to using C macros in C and XS code.
-
-=item *
-
-A new section, L<perlhacktips/Choosing good symbol names>, has been added to
-discuss unexpected gotchas with names.
-
-=back
-
-=head3 L<perlop>
-
-=over 4
-
-=item *
-
-Document the behavior of matching the empty pattern better and specify
-its relationship to the new C<${^LAST_SUCCESSFUL_PATTERN}> properly.
-
-=back
-
-=cut
-
-=head3 L<perlvar>
-
-=over 4
-
-=item *
-
-Added a section on "Scoping Rules of Regex Variables", and other wording
-improvements made throughout.
-
-=item *
-
-Added information on the new C<%{^HOOK}> interface, and the new
-C<require__before> and C<require__after> hooks which it exposes.
-
-=item *
-
-Correct information on the regex variables C<${^PREMATCH}>, C<${^MATCH}>
-and C<${^POSTMATCH}>, all of which were incorrectly documented due to an
-oversight. Specifically they only work properly after a regex operation
-that used the /p modifier to enable them.
-
-=item *
-
-Added information on the new regex variable C<${^LAST_SUCCESSFUL_PATTERN}>,
-which represents the pattern of the last successful regex match in scope.
-
-=back
-
-=head1 Diagnostics
-
-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>.
-
-=head2 New Diagnostics
-
-=head3 New Errors
-
-=over 4
-
-=item *
-
-A new syntax error has been added for the error that a C<catch> block does
-not have its required variable declaration. See
-L<catch block requires a (VAR)|perldiag/"catch block requires a (VAR)">
-
-=item *
-
-L<Too many nested BEGIN blocks, maximum of %d allowed|perldiag/"Too many nested BEGIN blocks, maximum of %d allowed">
-
-=item *
-
-L<Execution of %s aborted due to compilation errors.|perldiag/"Execution of %s aborted due to compilation errors.">
-
-=item *
-
-L<Attempt to bless into a class|perldiag/"Attempt to bless into a class">
-
-(F) You are attempting to call C<bless> with a package name that is a
-new-style C<class>. This is not necessary, as instances created by the
-constructor are already in the correct class. Instances cannot be created
-by other means, such as C<bless>.
-
-=item *
-
-L<Cannot assign :param(%s) to field %s because that name is already in use|perldiag/"Cannot assign :param(%s) to field %s because that name is already in use">
-
-(F) An attempt was made to apply a parameter name to a field, when the name
-is already being used by another field in the same class, or one of its
-parent classes. This would cause a name clash so is not allowed.
-
-=item *
-
-L<Cannot create class %s as it already has a non-empty @ISA|perldiag/"Cannot create class %s as it already has a non-empty @ISA">
-
-(F) An attempt was made to create a class out of a package that already has
-an C<@ISA> array, and the array is not empty. This is not permitted, as it
-would lead to a class with inconsistent inheritance.
-
-=item *
-
-L<Cannot invoke a method of "%s" on an instance of "%s"|perldiag/"Cannot invoke a method of "%s" on
-an instance of "%s"">
-
-(F) You tried to directly call a C<method> subroutine of one class by passing
-in a value that is an instance of a different class. This is not permitted,
-as the method would not have access to the correct instance fields.
-
-=item *
-
-L<Cannot invoke method on a non-instance|perldiag/"Cannot invoke method on a non-instance">
-
-(F) You tried to directly call a C<method> subroutine of a class by passing
-in a value that is not an instance of that class. This is not permitted, as
-the method would not then have access to its instance fields.
-
-=item *
-
-L<Cannot '%s' outside of a 'class'|perldiag/"Cannot '%s' outside of a 'class'">
-
-(F) You attempted to use one of the keywords that only makes sense inside
-a C<class> definition, at a location that is not inside such a class.
-
-=item *
-
-L<Cannot reopen existing class "%s"|perldiag/"Cannot reopen existing class "%s"">
-
-(F) You tried to begin a C<class> definition for a class that already exists.
-A class may only have one definition block.
-
-=item *
-
-L<Can't bless an object reference|perldiag/"Can't bless an object reference">
-
-(F) You attempted to call C<bless> on a value that already refers to a real
-object instance.
-
-=item *
-
-L<can't convert empty path|perldiag/"can't convert empty path">
-
-(F) On Cygwin, you called a path conversion function with an empty path.
-Only non-empty paths are legal.
-
-=item *
-
-L<Class already has a superclass, cannot add another|perldiag/"Class already has a superclass, cannot add another">
-
-(F) You attempted to specify a second superclass for a C<class> by using
-the C<:isa> attribute, when one is already specified. Unlike classes
-whose instances are created with C<bless>, classes created via the
-C<class> keyword cannot have more than one superclass.
-
-=item *
-
-L<Class attribute %s requires a value|perldiag/"Class attribute %s requires a value">
-
-(F) You specified an attribute for a class that would require a value to
-be passed in parentheses, but did not provide one. Remember that
-whitespace is B<not> permitted between the attribute name and its value;
-you must write this as
-
- class Example::Class :attr(VALUE) ...
-
-=item *
-
-L<Class :isa attribute requires a class but "%s" is not one|perldiag/"Class :isa attribute requires a class but "%s" is not one">
-
-(F) When creating a subclass using the C<class> C<:isa> attribute, the
-named superclass must also be a real class created using the C<class>
-keyword.
-
-=item *
-
-L<Field already has a parameter name, cannot add another|perldiag/"Field already has a parameter name, cannot add another">
-
-(F) A field may have at most one application of the C<:param> attribute to
-assign a parameter name to it; once applied a second one is not allowed.
-
-=item *
-
-L<Field attribute %s requires a value|perldiag/"Field attribute %s requires a value">
-
-(F) You specified an attribute for a field that would require a value to
-be passed in parentheses, but did not provide one. Remember that
-whitespace is B<not> permitted between the attribute name and its value;
-you must write this as
-
- field $var :attr(VALUE) ...
-
-=item *
-
-L<Field %s is not accessible outside a method|perldiag/"Field %s is not accessible outside a method">
-
-(F) An attempt was made to access a field variable of a class from code
-that does not appear inside the body of a C<method> subroutine. This is not
-permitted, as only methods will have access to the fields of an instance.
-
-=item *
-
-L<Field %s of "%s" is not accessible in a method of "%s"|perldiag/"Field %s of "%s" is not accessible in a method of "%s"">
-
-(F) An attempt was made to access a field variable of a class, from a
-method of another class nested inside the one that actually defined it.
-This is not permitted, as only methods defined by a given class are
-permitted to access fields of that class.
-
-=item *
-
-L<Only scalar fields can take a :param attribute|perldiag/"Only scalar fields can take a :param attribute">
-
-(F) You tried to apply the C<:param> attribute to an array or hash field.
-Currently this is not permitted.
-
-=item *
-
-L<Required parameter '%s' is missing for %s constructor|perldiag/"Required parameter '%s' is missing for %s constructor">
-
-(F) You called the constructor for a class that has a required named
-parameter, but did not pass that parameter at all.
-
-=item *
-
-L<Unexpected characters while parsing class :isa attribute: %s|perldiag/"Unexpected characters while parsing class :isa attribute: %s">
-
-(F) You tried to specify something other than a single class name with an
-optional trailing version number as the value for a C<class> C<:isa>
-attribute. This confused the parser.
-
-=item *
-
-L<Unrecognized class attribute %s|perldiag/"Unrecognized class attribute %s">
-
-(F) You attempted to add a named attribute to a C<class> definition, but
-perl does not recognise the name of the requested attribute.
-
-=item *
-
-L<Unrecognized field attribute %s|perldiag/"Unrecognized field attribute %s">
-
-(F) You attempted to add a named attribute to a C<field> definition, but
-perl does not recognise the name of the requested attribute.
-
-=item *
-
-L<${^HOOK}{%s} may only be a CODE reference or undef|perldiag/"${^HOOK}{%s} may only be a CODE reference or undef">
-
-=item *
-
-L<Attempt to set unknown hook '%s' in %{^HOOK}|perldiag/"Attempt to set unknown hook '%s' in %{^HOOK}">
-
-=item *
-
-L<Missing or undefined argument to %s via %{^HOOK}{require__before}|perldiag/"Missing or undefined argument to %s via %{^HOOK}{require__before}">
-
-=item *
-
-L<Too many capture groups (limit is %d) in regex mE<sol>%sE<sol>|perldiag/"Too many capture groups (limit is %d) in regex m/%s/">
-
-=back
-
-=head3 New Warnings
-
-=over 4
-
-=item *
-
-L<Unknown locale category %d|perldiag/"Unknown locale category %d">
-
-This is a shortened form of an already existing diagnostic, for use when
-there is no new locale being switched to. The previous diagnostic was
-misleading in such circumstances.
-
-=item *
-
-L<Locale '%s' is unsupported, and may crash the interpreter.|perldiag/"Locale '%s' is unsupported, and may crash the interpreter.">
-
-=item *
-
-L<Treating %s::INIT block as BEGIN block as workaround|perldiag/"Treating %s::INIT block as BEGIN block as workaround">
-
-=item *
-
-L<Filehandle STD%s reopened as %s only for input|perldiag/"Filehandle STD%s reopened as %s only for input">
-
-=item *
-
-L<%s on BEGIN block ignored|perldiag/"%s on BEGIN block ignored">
-
-=item *
-
-L<ADJUST is experimental|perldiag/"ADJUST is experimental">
-
-(S experimental::class) This warning is emitted if you use the C<ADJUST>
-keyword of C<use feature 'class'>. This keyword is currently
-experimental and its behaviour may change in future releases of Perl.
-
-=item *
-
-L<class is experimental|perldiag/"class is experimental">
-
-(S experimental::class) This warning is emitted if you use the C<class>
-keyword of C<use feature 'class'>. This keyword is currently
-experimental and its behaviour may change in future releases of Perl.
-
-=item *
-
-L<Method %s redefined|perldiag/"Method %s redefined">
-
-(W redefine) You redefined a method. To suppress this warning, say
-
- {
- no warnings 'redefine';
- *name = method { ... };
- }
-
-=item *
-
-L<Odd number of elements in hash field initialization|perldiag/"Odd number of elements in hash field initialization">
-
-(W misc) You specified an odd number of elements to initialise a hash
-field of an object. Hashes are initialised from a list of key/value
-pairs so there must be a corresponding value to every key. The final
-missing value will be filled in with undef instead.
-
-=item *
-
-L<Old package separator "'" deprecated|perldiag/"Old package separator "'" deprecated">
-
-(W deprecated, syntax) You used the old package separator "'" in a
-variable, subroutine or package name. Support for the old package
-separator will be removed in Perl 5.40.
-
-=item *
-
-L<field is experimental|perldiag/"field is experimental">
-
-(S experimental::class) This warning is emitted if you use the C<field>
-keyword of C<use feature 'class'>. This keyword is currently
-experimental and its behaviour may change in future releases of Perl.
-
-=item *
-
-L<method is experimental|perldiag/"method is experimental">
-
-(S experimental::class) This warning is emitted if you use the C<method>
-keyword of C<use feature 'class'>. This keyword is currently
-experimental and its behaviour may change in future releases of Perl.
-
-=item *
-
-L<Can't call destructor for 0x%p in global destruction|perldiag/"Can't call destructor for 0x%p in global destruction">
-
-
-=back
-
-=head2 Changes to Existing Diagnostics
-
-=over 4
-
-=item *
-
-The compiler will now stop parsing on the first syntax error it
-encounters. Historically the compiler would attempt to "skip past" the
-error and continue parsing so that it could list multiple errors. For
-things like undeclared variables under strict this makes sense. For
-syntax errors however it has been found that continuing tends to result
-in a storm of unrelated or bizarre errors that mostly just obscure the
-true error. In extreme cases it can even lead to segfaults and other
-incorrect behavior.
-
-Therefore we have reformed the continuation logic so that the parse will
-stop after the first seen syntax error. Semantic errors like undeclared
-variables will not stop the parse, so you may still see multiple errors
-when compiling code. However if there is a syntax error it will be the
-last error message reported by perl and all of the errors that you see
-will be something that actually needs to be fixed.
-
-=item *
-
-Error messages that output class or package names have been modified to
-output double quoted strings with various characters escaped so as to
-make the exact value clear to a reader. The exact rules on which
-characters are escaped may change over time but currently are that
-printable ASCII codepoints, with the exception of C<"> and C<\>, and
-unicode word characters whose codepoint is over 255 are output raw, and
-any other symbols are escaped much as Data::Dumper might escape them,
-using C<\n> for newline and C<\"> for double quotes, etc. Codepoints in
-the range 128-255 are always escaped as they can cause trouble on
-unicode terminals when output raw.
-
-In older versions of perl the one liner
-
- $ perl -le'"thing\n"->foo()'
-
-would output the following error message exactly as shown here, with
-text spread over multiple lines because the "\n" would be emitted as
-a raw newline character:
-
- Can't locate object method "foo" via package "thing
- " (perhaps you forgot to load "thing
- "?) at -e line 1.
-
-As of this release we would output this instead (as one line):
-
- Can't locate object method "foo" via package "thing\n"
- (perhaps you forgot to load "thing\n"?) at -e line 1.
-
-Notice the newline in the package name has been quoted and escaped, and
-thus the error message is a single line. The text is shown here wrapped
-to two lines only for readability.
-
-=item *
-
-When package or class names in errors are very large the middle excess
-portion will be elided from the message. As of this release error messages
-will show only up to the first 128 characters and the last 128 characters
-in a package or class name in error messages. For example
-
- $ perl -le'("Foo" x 1000)->new()'
-
-will output the following as one line:
-
- Can't locate object method "new" via package "FooFooFooFooFooFooFoo
- FooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFoo
- FooFooFooFooFooFooFooFooFooFooFooFooFooFo"..."oFooFooFooFooFooFooFoo
- FooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFoo
- FooFooFooFooFooFooFooFooFooFooFooFooFoo" (perhaps you forgot to load
- "FooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFoo
- FooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFo"...
- "oFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFoo
- FooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFoo"?)
- at -e line 1.
-
-Notice the C< "prefix"..."suffix" > form of the package name in this case.
-In previous versions of perl the complete string would have been shown
-making the error message over 6k long and there was no upper limit on the
-length of the error message at all. If you accidentally used a 1MB string
-as a class name then the error message would be over 2MB long. In this perl
-the upper limit should be around 2k when eliding and escaping are taken into
-account.
-
-=item *
-
-Removed C<< Complex regular subexpression recursion limit (%d) exceeded >>
-
-The regular expresion engine has not used recursion in some time. This
-warning no longer makes sense.
-
-See [L<GH #19636|https://github.com/Perl/perl5/pull/19636>].
-
-=item *
-
-Various warnings that used to produce parenthesized hints underneath the
-main warning message and after its "location data" were chanaged to put
-the hint inline with the main message. For instance:
-
- Bareword found where operator expected at -e line 1, near "foo bar"
- (Do you need to predeclare foo?)
-
-will now look like this but as one line:
-
- Bareword found where operator expected (Do you need to predeclare
- foo?) at -e line 1, near "foo bar"
-
-as a result such warnings will no longer trigger C<$SIG{__WARN__}>
-twice, and the hint will be visible when fatal warnings is in effect.
-
-=item *
-
-The error message that is produced when a C<require> or C<use> statement
-fails has been changed. It used to contain the words C<@INC contains:>,
-and it used to show the state of C<@INC> *after* the require had
-completed and failed. The error message has been changed to say C<@INC
-entries checked:> and to reflect the actual directories or hooks that
-were executed during the require statement. For example:
-
- perl -e'push @INC, sub {@INC=()}; eval "require Frobnitz"
- or die $@'
- Can't locate Frobnitz.pm in @INC (you may need to install the
- Frobnitz module) (@INC contains:) at (eval 1) line 1.
-
-Will change to (with some output elided for clarity):
-
- perl -e'push @INC, sub {@INC=()}; eval "require Frobnitz"
- or die $@'
- Can't locate Frobnitz.pm in @INC (you may need to install the
- Frobnitz module) (@INC entries checked:
- .../site_perl/5.38.0/x86_64-linux .../site_perl/5.38.0
- .../5.38.0/x86_64-linux .../5.38.0 CODE(0x562745e684b8))
- at (eval 1) line 1.
-
-thus showing the actual directories checked. Code that checks for
-C<@INC contains:> in error messages should be hardened against any future
-wording changes between the C<@INC> and C<:>, for instance use
-C<qr/\@INC[ \w]+:/> instead of using C<qr/\@INC contains:/> or
-C<qr/\@INC entries checked:/> in tests as this will ensure both forward
-and backward compatibility.
-
-=item *
-
-L<Old package separator used in string|perldiag/"Old package separator used in string">
-
-This diagnostic is now also part of the C<deprecated> category.
-
-=item *
-
-L<given is deprecated|perldiag/"given is deprecated"> replaces C<given is experimental>.
-
-=item *
-
-L<when is deprecated|perldiag/"when is deprecated"> replaces C<when is experimental>.
-
-=item *
-
-L<Smartmatch is deprecated|perldiag/"Smartmatch is deprecated"> replaces C<Smartmatch is experimental>.
-
-=back
-
-=head1 Configuration and Compilation
-
-=over 4
-
-=item *
-
-C<make -j6 minitest> could fail due to a build conflict in building
-C<$(MINIPERL_EXE)> between the main make process and a child process.
-[github #19829]
-
-=item *
-
-Properly populate osvers on Dragonfly BSD when the hostname isn't set.
-
-=item *
-
-Fix typos for C99 macro name PRIX64.
-
-=item *
-
-Remove ancient and broken GCC for VMS support
-
-=item *
-
-Remove vestigial reference to /VAXC qualifier
-
-=item *
-
-Remove sharedperl option on VMS
-
-=item *
-
-VMS now has mkostemp
-
-=item *
-
-C<Configure> now properly handles quoted elements outputted by gcc.
-[L<GH #20606|https://github.com/Perl/perl5/issues/20606>]
-
-=item *
-
-C<Configure> probed for the return type of malloc() and free() by
-testing whether declarations for those functions produced a function
-type mismatch with the implementation. On Solaris, with a C++
-compiler, this check always failed, since Solaris instead imports
-malloc() and free() from C<std::> with C<using> for C++ builds. Since
-the return types of malloc() and free() are well defined by the C
-standard, skip probing for them. C<Configure> command-line arguments
-and hints can still override these type in the unlikely case that is
-needed. [L<GH #20806|https://github.com/Perl/perl5/issues/20806>]
-
-=back
-
-=head1 Testing
-
-Tests were added and changed to reflect the other additions and
-changes in this release. Furthermore, these significant changes were
-made:
-
-=over 4
-
-=item *
-
-Unicode normalization tests have been added.
-
-=item *
-
-t/test.pl: Add ability to cancel an watchdog timer
-
-=back
-
-=head1 Platform Support
-
-=head2 Discontinued Platforms
-
-=over 4
-
-=item Ultrix
-
-Support code for DEC Ultrix has been removed. Ultrix was the native
-Unix-like operating system for various Digital Equipment Corporation
-machines. Its final release was in 1995.
-
-=back
-
-=head2 Platform-Specific Notes
-
-=over 4
-
-=item DragonflyBSD
-
-Skip tests to workaround an apparent bug in setproctitle(). [L<github #19894|https://github.com/Perl/perl5/issues/19894>]
-
-=item FreeBSD
-
-FreeBSD no longer uses thread-safe locale operations, to avoid L<a bug in
-FreeBSD|https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=265950>
-
-Replace the first part of archname with `uname -p` [L<github #19791|https://github.com/Perl/perl5/issues/19791>]
-
-=item Solaris
-
-Avoid some compiler and compilation issues on NetBSD/Solaris from regexec.c and regcomp.c.
-
-=item Synology
-
-Update Synology Readme for DSM 7.
-
-=item Windows
-
-Fix win32 memory alignment needed for gcc-12 from vmem.h.
-
-utimes() on Win32 would print a message to stderr if it failed to
-convert a supplied C<time_t> to to a C<FILETIME>. [github #19668]
-
-In some cases, timestamps returned by L<stat()|perlfunc/stat> and
-L<lstat()|perlfunc/lstat> failed to take daylight saving time into account.
-[L<GH #20018|https://github.com/Perl/perl5/issues/20018>]
-[L<GH #20061|https://github.com/Perl/perl5/issues/20061>]
-
-stat() now works on AF_UNIX socket files. [github #20204]
-
-readlink() now returns the C<PrintName> from a symbolic link reparse
-point instead of the C<SubstituteName>, which should make it better
-match the name the link was created with. [github #20271]
-
-lstat() on Windows now returns the length of the link target as the
-size of the file, as it does on POSIX systems. [github #20476]
-
-symlink() on Windows now replaces any C</> in the target with C<\>,
-since Windows does not recognise C</> in symbolic links. The reverse
-translation is B<not> done by readlink(). [github #20506]
-
-symlink() where the target was an absolute path to a directory was
-incorrectly created as a file symbolic link. [github #20533]
-
-C<POSIX::dup2> no longer creates broken sockets. [L<GH
-#20920|https://github.com/Perl/perl5/issues/20920>]
-
-Closing a busy pipe could cause Perl to hang. [L<GH
-#19963|https://github.com/Perl/perl5/issues/19963>]
+=head1 Modules and Pragmata
-=back
+The list of new and updated modules is modified automatically as part of
+preparing a Perl release, so the only reason to manually add entries here is if
+you're summarising the important changes in the module update. (Also, if the
+manually-added details don't match the automatically-generated ones, the
+release manager will have to investigate the situation carefully.)
-=head1 Internal Changes
+=head2 Updated Modules and Pragmata
=over 4
=item *
-Removed many deprecated C functions.
-
-These have been deprecated for a long time. See
-L<https://github.com/perl/perl5/commit/7008caa915ad99e650acf2aea40612b5e48b7ba2>
-for a full list.
+L<Exporter> has been upgraded from version 5.77 to 5.78.
=item *
-C<get_op_descs>, C<get_op_names>, C<get_opargs>, C<get_no_modify> and
-C<get_ppaddr> have been marked deprecated.
+L<Hash::Util> has been upgraded from version 0.30 to 0.31.
=item *
-C<hv_free_ent> has been marked as internal API.
-
-=item *
+L<I18N::Langinfo> has been upgraded from version 0.22 to 0.23.
-C<save_pushptr>, C<save_pushptrptr>, and C<save_pushi32ptr> have been marked
-as internal API.
+It now handles the additional locale categories that Linux defines
+beyond those in the POSIX Standard.
=item *
-New bool related functions and macros have been added to complement the new
-bool type introduced in 5.36:
-
-The functions are:
-
-=over 4
-
-=item L<C<newSVbool(const bool bool_val)>|perlapi/newSVbool>
-
-=item L<C<newSV_true()>|perlapi/newSV_true>
-
-=item L<C<newSV_false()>|perlapi/newSV_false>
-
-=item L<C<sv_set_true(SV *sv)>|perlapi/sv_set_true>
-
-=item L<C<sv_set_false(SV *sv)>|perlapi/sv_set_false>
-
-=item L<C<sv_set_bool(SV *sv, const bool bool_val)>|perlapi/sv_set_bool>
-
-=back
-
-The macros are:
-
-=over 4
-
-=item L<C<SvIandPOK(sv)>|perlapi/SvIandPOK>
-
-=item L<C<SvIandPOK_off(sv)>|perlapi/SvIandPOK_off>
-
-=item L<C<SvIandPOK_on>|perlapi/SvIandPOK_on>
-
-=back
+L<Math::BigInt> has been upgraded from version 2.003001 to 2.003002.
=item *
-Perl is no longer manipulating the C<environ> array directly. The variable
-C<PL_use_safe_putenv> has been removed and C<PERL_USE_SAFE_PUTENV> is always
-defined. This means XS modules can now call C<setenv> and C<putenv> without
-causing segfaults. [L<perl #19399|https://github.com/Perl/perl5/issues/19399>]
+L<Math::BigInt::FastCalc> has been upgraded from version 0.5016 to 0.5018.
=item *
-Internal C API functions are now hidden with C<__attribute__((hidden))> on the
-platforms that support it. This means they are no longer callable from XS
-modules on those platforms.
-
-It should be noted that those functions have always been hidden on Windows. This
-change merely brings that to the other platforms.
-[L<perl #19655|https://github.com/Perl/perl5/pull/19655>]
+L<Pod::Checker> has been upgraded from version 1.75 to 1.76.
=item *
-New formatting symbols were added for printing values declared as U32 or
-I32:
-
-=over
-
-=item I32df -- Like %d
-
-=item U32of -- Like %o
-
-=item U32uf -- Like %u
-
-=item U32xf -- Like %x
-
-=item U32Xf -- Like %X
+L<SelfLoader> has been upgraded from version 1.26 to 1.27.
=back
-These are used in the same way already existing similar symbols, such as
-C<IVdf>, are used. See L<perlapi/I/O Formats>.
-
-=item *
-
-new 'HvHasAUX' macro
-
-=item *
-
-regexec.c: Add some branch predictions reorder conds
-
-=item *
-
-locale: Change macro name to be C conformant
-
-=item *
-
-Rename the C<PADNAMEt_*> constants to C<PADNAMEf_*>
-
-=item *
-
-Changes all the API macros that retrieve a PV into a call to an
-inline function so as to evaluate the parameter just once.
-
-=item *
-
-regexec.c: multiple code refactor to make the code more readable
-
-=item *
-
-perl.h: Change macro name to be C conformant
-(remove leading _ from NOT_IN_NUMERIC macros)
-
-=item *
-
-regcomp.h: add new C<BITMAP_BIT> macro in addition to the existing C<BITMAP_BYTE>
-and C<BITMAP_TEST> ones.
-
-=item *
-
-Create new regnode type ANYOFH.
-populate_ANYOF_from_invlist was renamed to populate_bitmap_from_invlist
-
-=item *
-
-regex: Refactor bitmap vs non-bitmap of qr/[]/
-
-=item *
-
-regcomp.c: add new functions to convert from an inversion list to a bitmap (and vice versa)
-C<populate_bitmap_from_invlist> and C<populate_invlist_from_bitmap>.
-
-=item *
-
-Add C<newAVav()> to create an AV from an existing AV.
-Add C<newAVhv()> to create an AV using keys and values from an existing HV.
-
-=item *
-
-Fix definition of C<Perl_atof>.
-
-=item *
-
-Fix undefined behavior with overflow related OPTIMIZE_INFTY and delta
-in F<regcomp.c>.
-
-=item *
-
-Fix regnode pointer alignment issue in F<regcomp.h>.
-
-=item *
-
-The C<CVf_METHOD> CV flag and associated C<CvMETHOD> macro has been renamed to
-C<CVf_NOWARN_AMBIGUOUS> and C<CvNOWARN_AMBIGUOUS>. This closer reflects its
-actual behaviour (it suppresses a warning that would otherwise be generated
-about ambiguous names), in order to be less confusing with a possible upcoming
-feature.
-
-=item *
-
-The C<OPf_SPECIAL> flag is no longer set on the C<OP_ENTERSUB> op
-constructed to call the C<VERSION>, C<import> and C<unimport> methods
-as part of a C<use> statement and attribute application, nor when
-assigning to an C<:lvalue> subroutine.
-
-=item *
-
-A new CV flag C<CVf_REFCOUNTED_ANYSV> has been added, which indicates that the
-CV is an XSUB and stores an SV pointer in the C<CvXSUBANY.any_sv> union field.
-Perl core operations such as cloning or destroying the CV will maintain the
-reference count of the pointed-to SV, destroying it when required.
-
-=item *
-
-A new API function L<perlapi/C<Perl_localeconv>> is added. This is the
-same as L<C<POSIX::localeconv>|POSIX/localeconv> (returning a hash of
-the C<localeconv()> fields), but directly callable from XS code.
-
-=item *
-
-A new API function, L<perlapi/C<Perl_langinfo8>> is added. This is the
-same as plain L<perlapi/C<Perl_langinfo>>, but with an extra parameter
-that allows the caller to simply and reliably know if the returned
-string is UTF-8.
-
-=item *
-
-We have introduced a limit on the number of nested C<eval EXPR>/C<BEGIN>
-blocks and C<require>/C<BEGIN> (and thus C<use> statements as well) to
-prevent C stack overflows. This variable can also be used to forbid
-C<BEGIN> blocks from executing during C<eval EXPR> compilation. The
-limit defaults to C<1000> but can be overridden by setting the
-C<${^MAX_NESTED_EVAL_BEGIN_BLOCKS}> variable. The default itself can be
-changed at compile time with
-
- -Accflags='-DPERL_MAX_NESTED_EVAL_BEGIN_BLOCKS_DEFAULT=12345'
-
-Note that this value relates to the size of your C stack and if you
-choose an inappropriately large value Perl may segfault, be conservative
-about what you choose.
-
-=item *
-
-A new magic type C<PERL_MAGIC_extvalue> has been added. This is available for
-use like C<PERL_MAGIC_ext>, but is a value magic: upon localization the new
-value will not be magical.
-
-=item *
-
-The C<SSNEW()>, C<SSNEWt()>, C<SSNEWa()> and C<SSNEWat()> APIs now
-return a C<SSize_t> value. The C<SSPTR()> and C<SSPTRt()> macros now
-expect a C<SSize_t> parameter, and enforce that on debugging builds.
-[github #20411]
-
-=item *
-
-Filenames in cops are now refcounted under threads.
-Under threads we were copying the filenames into each opcode. This is because in
-theory opcodes created in one thread can be destroyed in another.
-The change adds a new struct/type RCPV, which is a refcounted
-string using shared memory. This is implemented in such a way that code
-that previously used a char * can continue to do so, as the refcounting
-data is located a specific offset before the char * pointer itself.
-
-=item *
-
-Added HvNAMEf and HvNAMEf_QUOTEDPREFIX special formats. They take an HV *
-as an argument and use C<HvNAME()> and related macros to determine the string,
-its length, and whether it is utf8.
-
-=item *
-
-The underlying C<Perl_dowantarray> function implementing the
-long-deprecated L<C<GIMME>|perlapi/GIMME> macro has been marked as
-deprecated, so that use of the macro emits a compile-time warning.
-C<GIMME> has been documented as deprecated in favour of
-L<C<GIMME_V>|perlapi/GIMME_V> since Perl v5.6.0, but had not
-previously issued a warning.
-
-=item *
-
-The API function L<perlapi/utf8_length> is now more efficient.
-
-=item *
-
-Added C<SAVERCPV()> and C<SAVEFREERCPV()> for better support for working
-with C<RCPV> (reference counted string/pointer value) structures which
-currently are used in opcodes to share filename and warning bit data in
-a memory efficient manner.
-
-=item *
-
-Added C<MORTALSVFUNC_SV()> and C<MORTALDESTRUCTOR_SV()> macros, which
-make it possible to create a destructor which is fired at the end of
-the current statement. This uses the C<PERL_MAGIC_destruct> magic to
-use "free" magic to trigger an action when a variable is freed. The
-action can be specified as a C function or as a Perl code reference.
-
-=item *
-
-Added the C<%{^HOOK}> api and related C<PERL_MAGIC_hook> and
-C<PERL_MAGIC_hookelem> for providing ways to hook selected perl functions
-which for one reason or another are problematic to wrap with a customized
-subroutine.
-
-=item *
-
-Added support for C<${^HOOK}{require__before}> which can be used to
-rewrite the filename that C<require> will try to load, and also to block
-C<require> from loading a specific module, even via fully qualified
-filename. The hook can also be used to perform "pre-require" and
-"post-require" actions.
-
-=item *
-
-Added support for C<${^HOOK}{require__after}> which can be used to
-track what modules have been required after the fact.
-
-=item *
+=head1 Documentation
-Regular expression opcodes (regops) now use a standardized structure
-layout that uses unions to expose data in different format. This means
-it should be much easier to extend or modify regops to use more memory.
-This has been used to make a number of regops track how many parens
-they contain.
+=head2 Changes to Existing Documentation
-=back
+We have attempted to update the documentation to reflect the changes
+listed in this document. If you find any we have missed, open an issue
+at L<https://github.com/Perl/perl5/issues>.
-=head1 Selected Bug Fixes
+=head1 Internal Changes
=over 4
=item *
-Avoid recursion and stack overflow parsing 'pack' template
-
-[L<GH #16319|https://github.com/Perl/perl5/issues/16319>]
-
-=item *
-
-An eval() as the last statement in a regex code block could trigger an
-interpreter panic; e.g.
-
- /(?{ ...; eval {....}; })/
-
-[L<GH #19680|https://github.com/Perl/perl5/issues/19680>]
-
-=item *
-
-Disabling the C<bareword_filehandles> feature no longer treats C<< print
-Class->method >> as an error. [L<github #19704|https://github.com/Perl/perl5/issues/19704>]
-
-=item *
-
-When a Perl subroutine tail-calls an XS subroutine using C<goto &xs_sub>,
-the XS subroutine can now correctly determine its calling context.
-Previously it was always reported as scalar.
-
-In addition, where the Perl subroutine is freed at the same time:
-
- sub foo { *foo = sub {}; goto &xs_sub }
-
-this formerly could lead to crashes if the XS subroutine tried to use the
-value of C<PL_op>, since this was being set to NULL. This is now fixed.
-
-[L<github #19936|https://github.com/Perl/perl5/issues/19936>]
-
-=item *
-
-setsockopt() now uses the mechanism added in 5.36 to better
-distinguish between numeric and string values supplied as the
-C<OPTVAL> parameter. [L<github #18761|https://github.com/Perl/perl5/issues/18761>]
-
-=item *
-
-4-argument C<select()> now rejects strings with code points above
-255. Additionally, for code points 128-255, this operator will now always
-give the corresponding octet to the OS, regardless of how Perl stores
-such code points in memory. (Previously Perl leaked its internal string
-storage to the OS.) [L<github #19882|https://github.com/Perl/perl5/issues/19882>]
-
-=item *
-
-Fix panic issue from C<val {} inside /(?{...})/> [L<github #19390|https://github.com/Perl/perl5/issues/19390>]
-
-=item *
-
-Fix multiple compiler warnings from regexp.c., locale.c [L<github #19915|https://github.com/Perl/perl5/issues/19915>]
-
-=item *
-
-Fix a bug with querying locales on platforms that don't have LC_NUMERIC
-[L<github #19890|https://github.com/Perl/perl5/issues/19890>]
+C<dAX>, C<dITEMS> and hence C<dXSARGS> now declare C<AX> and C<items>
+as C<Stack_off_t> rather than C<SSize_t>. This reverts back to
+compatibility with pre-64-bit stack support for default builds of perl
+where C<Stack_off_t> is C<I32>. [GH #21782]
=item *
-Prevent undefined behaviour in C<S_maybe_multideref()>.
-
-=item *
-
-Avoid signed integer overflow in C<use integer> ops.
-
-=item *
-
-Avoid adding an offset to a NULL pointer in C<hv_delete_common>.
-
-=item *
-
-PerlIO::get_layers will now accept IO references too
-
-Previously it would only take glob references or names of globs. Now it will
-also accept IO references.
-
-=item *
-
-Fixes to memory handling for C<PL_splitstr>:
-
-=over
-
-=item *
-
-If a thread was created the allocated string would be freed twice.
-
-=item *
-
-If two C<-F> switches were supplied the memory allocated for the first
-switch wouldn't be freed.
+A new function is now available to C<XS> code, L<perlapi/sv_langinfo>.
+This provides the same information as the existing
+L<perlapi/Perl_langinfo8>, but returns an SV instead of a S<C<char *>>,
+so that programmers don't have to concern themselves with the UTF-8ness
+of the result. This new function is now the preferred interface for
+C<XS> code to the L<nl_langinfo(3)> C<libc> function. From Perl space,
+this information continues to be provided by the L<I18N::Langinfo>
+module.
=back
-=item *
-
-Correctly handle C<OP_ANONCODE> ops generated by CPAN modules that
-don't include the OPf_REF flag when propagating lvalue context.
-L<[GH #20532]|https://github.com/Perl/perl5/pull/20532>
-
-=item *
-
-L<POSIX::strxfrm|POSIX/strxfrm> now uses the C<LC_CTYPE> locale category
-to specify its collation, ignoring any differing C<LC_COLLATE>. It
-doesn't make sense for a string to be encoded in one locale (say,
-ISO-8859-6, Arabic) and to collate it based on another (like ISO-8859-7,
-Greek). Perl assumes that the current C<LC_CTYPE> locale correctly
-represents the encoding, and collates accordingly.
-
-Also, embedded C<NUL> characters are now allowed in the input.
-
-If locale collation is not enabled on the platform (C<LC_COLLATE>), the
-input is returned unchanged.
-
-=item *
-
-Double FETCH during stringification of tied scalars returning an
-overloaded object have been fixed. The FETCH method should only be
-called once, but prior to this release was actually called twice.
-L<[GH #20574]|https://github.com/Perl/perl5/pull/20574>
-
-=item *
-
-Writing to a magic variables associated with the selected output
-handle, C<$^>, C<$~>, C<$=>, C<$-> and C<$%>, no longer crashes perl
-if the IO object has been cleared from the selected output
-handle. [L<GH #20733|https://github.com/Perl/perl5/issues/20733>]
-
-=item *
-
-Redefining a C<use constant> list constant with C<use constant> now
-properly warns. This changes the behaviour of C<use constant> but is
-a core change, not a change to F<constant.pm>. [L<GH #20742|https://github.com/Perl/perl5/issues/20742>]
-
-=item *
-
-Redefining a C<use constant> list constant with an empty prototype
-constant sub would result in an assertion failure. [L<GH #20742|https://github.com/Perl/perl5/issues/20742>]
-
-=item *
-
-Fixed a regression where the C<INC> method for objects in C<@INC>
-would not be resolved by C<AUTOLOAD>, while it was in 5.36. The
-C<INCDIR> method for objects in C<@INC> cannot be resolved by
-C<AUTOLOAD> as C<INC> would have been resolved first. [L<GH #20665|https://github.com/Perl/perl5/issues/20665>]
-
-=item *
-
-C<$SIG{__DIE__}> will now be called from eval when the code dies during
-compilation regardless of how it dies. This means that code expecting to
-be able to upgrade C<$@> into an object will be called consistently. In
-earlier versions of perl C<$SIG{__DIE__}> would not be called for
-certain compilation errors, for instance undeclared variables. For other
-errors it might be called if there were more than a certain number of
-errors, but not if there were less. Now you can expect that it will be
-called in every case.
-
-=item *
-
-Compilation of code with errors used to inconsistently stop depending on
-the count and type of errors encountered. The intent was that after 10
-errors compilation would halt, but bugs in this logic meant that certain
-types of error would be counted, but would not trigger the threshold
-check to stop compilation. Other errors would. With this release after
-at most 10 errors compilation will terminate, regardless of what type of
-error they were.
+=head1 Known Problems
-Note that you can change the maximum count by defining
-C<PERL_STOP_PARSING_AFTER_N_ERRORS> to be something else during the
-configuration process. For instance
-
- ./Configure ... -Accflags='-DPERL_STOP_PARSING_AFTER_N_ERRORS=100'
-
-would allow up to 100 errors.
-
-=item *
-
-The API function L<perlapi/my_snprintf> now prints a non-dot decimal
-point if the perl code it ultimately is called from is in the scope of
-C<use locale> and the locale in effect calls for that.
-
-=item *
-
-A number of bugs related to capture groups in quantified groups in regular
-expression have been fixed, especially in alternations. For example in
-a pattern like:
-
- "foobazfoobar" =~ /((foo)baz|foo(bar))+/
-
-the regex variable C<$2> will not be "foo" as it once was, it will be undef.
-
-=item *
-
-Bugs with regex backreference operators that are inside of a capture
-group have been fixed. For instance:
-
- "xa=xaaa" =~ /^(xa|=?\1a){2}\z/
-
-will now correctly not match. [L<GH #10073|https://github.com/Perl/perl5/issues/10073>]
+=over 4
=item *
-C<SSGROW()> and C<SSCHECK()> have been reworked to ensure that the requested
-space is actually allocated. C<SSCHECK()> is now an alias for C<SSGROW()>.
+none
=back
=head1 Acknowledgements
-Perl 5.38.0 represents approximately 12 months of development since Perl
-5.36.0 and contains approximately 290,000 lines of changes across 1,500
-files from 100 authors.
+Perl 5.39.7 represents approximately 3 weeks of development since Perl
+5.39.6 and contains approximately 7,300 lines of changes across 160 files
+from 16 authors.
Excluding auto-generated files, documentation and release tools, there were
-approximately 190,000 lines of changes to 970 .pm, .t, .c and .h files.
+approximately 5,600 lines of changes to 79 .pm, .t, .c and .h files.
Perl continues to flourish into its fourth decade thanks to a vibrant
community of users and developers. The following people are known to have
-contributed the improvements that became Perl 5.38.0:
+contributed the improvements that became Perl 5.39.7:
-Alex, Alexander Nikolov, Alex Davies, Andreas König, Andrew Fresh, Andrew
-Ruthven, Andy Lester, Aristotle Pagaltzis, Arne Johannessen, A. Sinan Unur,
-Bartosz Jarzyna, Bart Van Assche, Benjamin Smith, Bram, Branislav
-Zahradník, Brian Greenfield, Bruce Gray, Chad Granum, Chris 'BinGOs'
-Williams, chromatic, Clemens Wasser, Craig A. Berry, Dagfinn Ilmari
-Mannsåker, Dan Book, danielnachun, Dan Jacobson, Dan Kogai, David Cantrell,
-David Golden, David Mitchell, E. Choroba, Ed J, Ed Sabol, Elvin Aslanov,
-Eric Herman, Felipe Gasper, Ferenc Erki, Firas Khalil Khana, Florian Weimer,
-Graham Knop, Håkon Hægland, Harald Jörg, H.Merijn Brand, Hugo van der
-Sanden, James E Keenan, James Raspass, jkahrman, Joe McMahon, Johan Vromans,
-Jonathan Stowe, Jon Gentle, Karen Etheridge, Karl Williamson, Kenichi
-Ishigaki, Kenneth Ölwing, Kurt Fitzner, Leon Timmermans, Li Linjie, Loren
-Merritt, Lukas Mai, Marcel Telka, Mark Jason Dominus, Mark Shelor, Matthew
-Horsfall, Matthew O. Persico, Mattia Barbon, Max Maischein, Mohammad S
-Anwar, Nathan Mills, Neil Bowers, Nicholas Clark, Nicolas Mendoza, Nicolas
-R, Paul Evans, Paul Marquess, Peter John Acklam, Peter Levine, Philippe
-Bruhat (BooK), Reini Urban, Renee Baecker, Ricardo Signes, Richard Leach,
-Russ Allbery, Scott Baker, Sevan Janiyan, Sidney Markowitz, Sisyphus, Steve
-Hay, TAKAI Kousuke, Todd Rinaldo, Tomasz Konojacki, Tom Stellard, Tony Cook,
-Tsuyoshi Watanabe, Unicode Consortium, vsfos, Yves Orton, Zakariyya Mughal,
-Zefram, 小鸡.
+Craig A. Berry, Dagfinn Ilmari Mannsåker, David Mitchell, Elvin Aslanov,
+H.Merijn Brand, James E Keenan, Karen Etheridge, Karl Williamson, Mathias
+Kende, Max Maischein, Peter John Acklam, Philippe Bruhat (BooK), Todd
+Rinaldo, Tony Cook, Yves Orton, Дилян Палаузов.
The list above is almost certainly incomplete as it is automatically
generated from version control history. In particular, it does not include
https://perl5.git.perl.org / perl5.git / blobdiff