=head1 NAME
-perldelta - what is new for perl v5.25.10
+perldelta - what is new for perl v5.26.0
=head1 DESCRIPTION
-This document describes differences between the 5.25.9 release and the 5.25.10
-release.
+This document describes the differences between the 5.24.0 release and the
+5.26.0 release.
-If you are upgrading from an earlier release such as 5.25.8, first read
-L<perl5259delta>, which describes differences between 5.25.8 and 5.25.9.
+=head1 Notice
+
+This release includes three updates with widespread effects:
+
+=over 4
+
+=item * C<"."> no longer in C<@INC>
+
+For security reasons, the current directory (C<".">) is no longer included
+by default at the end of the module search path (C<@INC>). This may have
+widespread implications for the building, testing and installing of
+modules, and for the execution of scripts. See the section
+L<< Removal of the current directory (C<".">) from C<@INC> >>
+for the full details.
+
+=item * C<do> may now warn
+
+C<do> now gives a deprecation warning when it fails to load a file which
+it would have loaded had C<"."> been in C<@INC>.
+
+=item * In regular expression patterns, a literal left brace C<"{">
+should be escaped
+
+See L</Unescaped literal C<"{"> characters in regular expression patterns are no longer permissible>.
+
+=back
+
+=head1 Core Enhancements
+
+=head2 Lexical subroutines are no longer experimental
+
+Using the C<lexical_subs> feature introduced in v5.18 no longer emits a warning. Existing
+code that disables the C<experimental::lexical_subs> warning category
+that the feature previously used will continue to work. The
+C<lexical_subs> feature has no effect; all Perl code can use lexical
+subroutines, regardless of what feature declarations are in scope.
+
+=head2 Indented Here-documents
+
+This adds a new modifier C<"~"> to here-docs that tells the parser
+that it should look for C</^\s*$DELIM\n/> as the closing delimiter.
+
+These syntaxes are all supported:
+
+ <<~EOF;
+ <<~\EOF;
+ <<~'EOF';
+ <<~"EOF";
+ <<~`EOF`;
+ <<~ 'EOF';
+ <<~ "EOF";
+ <<~ `EOF`;
+
+The C<"~"> modifier will strip, from each line in the here-doc, the
+same whitespace that appears before the delimiter.
+
+Newlines will be copied as-is, and lines that don't include the
+proper beginning whitespace will cause perl to croak.
+
+For example:
+
+ if (1) {
+ print <<~EOF;
+ Hello there
+ EOF
+ }
+
+prints "Hello there\n" with no leading whitespace.
+
+=head2 New regular expression modifier C</xx>
+
+Specifying two C<"x"> characters to modify a regular expression pattern
+does everything that a single one does, but additionally TAB and SPACE
+characters within a bracketed character class are generally ignored and
+can be added to improve readability, like
+S<C</[ ^ A-Z d-f p-x ]/xx>>. Details are at
+L<perlre/E<sol>x and E<sol>xx>.
+
+=head2 C<@{^CAPTURE}>, C<%{^CAPTURE}>, and C<%{^CAPTURE_ALL}>
+
+C<@{^CAPTURE}> exposes the capture buffers of the last match as an
+array. So C<$1> is C<${^CAPTURE}[0]>. This is a more efficient equivalent
+to code like C<substr($matched_string,$-[0],$+[0]-$-[0])>, and you don't
+have to keep track of the C<$matched_string> either. This variable has no
+single character equivalent. Note that, like the other regex magic variables,
+the contents of this variable is dynamic; if you wish to store it beyond
+the lifetime of the match you must copy it to another array.
+
+C<%{^CAPTURE}> is equivalent to C<%+> (I<i.e.>, named captures). Other than
+being more self documenting there is no difference between the two forms.
+
+C<%{^CAPTURE_ALL}> is equivalent to C<%-> (I<i.e.>, all named captures).
+Other than being more self documenting there is no difference between the
+two forms.
+
+=head2 Declaring a reference to a variable
+
+As an experimental feature, Perl now allows the referencing operator to come
+after L<C<my()>|perlfunc/my>, L<C<state()>|perlfunc/state>,
+L<C<our()>|perlfunc/our>, or L<C<local()>|perlfunc/local>. This syntax must
+be enabled with C<use feature 'declared_refs'>. It is experimental, and will
+warn by default unless C<no warnings 'experimental::refaliasing'> is in effect.
+It is intended mainly for use in assignments to references. For example:
+
+ use experimental 'refaliasing', 'declared_refs';
+ my \$a = \$b;
+
+See L<perlref/Assigning to References> for more details.
+
+=head2 Unicode 9.0 is now supported
+
+A list of changes is at L<http://www.unicode.org/versions/Unicode9.0.0/>.
+Modules that are shipped with core Perl but not maintained by p5p do not
+necessarily support Unicode 9.0. L<Unicode::Normalize> does work on 9.0.
+
+=head2 Use of C<\p{I<script>}> uses the improved Script_Extensions property
+
+Unicode 6.0 introduced an improved form of the Script (C<sc>) property, and
+called it Script_Extensions (C<scx>). Perl now uses this improved
+version when a property is specified as just C<\p{I<script>}>. This
+should make programs be more accurate when determining if a character is
+used in a given script, but there is a slight chance of breakage for
+programs that very specifically needed the old behavior. The meaning of
+compound forms, like C<\p{sc=I<script>}> are unchanged. See
+L<perlunicode/Scripts>.
+
+=head2 Perl can now do default collation in UTF-8 locales on platforms
+that support it
+
+Some platforms natively do a reasonable job of collating and sorting in
+UTF-8 locales. Perl now works with those. For portability and full
+control, L<Unicode::Collate> is still recommended, but now you may
+not need to do anything special to get good-enough results, depending on
+your application. See
+L<perllocale/Category C<LC_COLLATE>: Collation: Text Comparisons and Sorting>.
+
+=head2 Better locale collation of strings containing embedded C<NUL>
+characters
+
+In locales that have multi-level character weights, C<NUL>s are now
+ignored at the higher priority ones. There are still some gotchas in
+some strings, though. See
+L<perllocale/Collation of strings containing embedded C<NUL> characters>.
+
+=head2 C<CORE> subroutines for hash and array functions callable via
+reference
+
+The hash and array functions in the C<CORE> namespace (C<keys>, C<each>,
+C<values>, C<push>, C<pop>, C<shift>, C<unshift> and C<splice>) can now
+be called with ampersand syntax (C<&CORE::keys(\%hash>) and via reference
+(C<< my $k = \&CORE::keys; $k-E<gt>(\%hash) >>). Previously they could only be
+used when inlined.
+
+=head2 New Hash Function For 64-bit Builds
+
+We have switched to a hybrid hash function to better balance
+performance for short and long keys.
+
+For short keys, 16 bytes and under, we use an optimised variant of
+One At A Time Hard, and for longer keys we use Siphash 1-3. For very
+long keys this is a big improvement in performance. For shorter keys
+there is a modest improvement.
+
+=head1 Security
+
+=head2 Removal of the current directory (C<".">) from C<@INC>
+
+The perl binary includes a default set of paths in C<@INC>. Historically
+it has also included the current directory (C<".">) as the final entry,
+unless run with taint mode enabled (C<perl -T>). While convenient, this has
+security implications: for example, where a script attempts to load an
+optional module when its current directory is untrusted (such as F</tmp>),
+it could load and execute code from under that directory.
+
+Starting with v5.26, C<"."> is always removed by default, not just under
+tainting. This has major implications for installing modules and executing
+scripts.
+
+The following new features have been added to help ameliorate these
+issues.
+
+=over
+
+=item * C<Configure -Udefault_inc_excludes_dot>
+
+There is a new C<Configure> option, C<default_inc_excludes_dot> (enabled
+by default) which builds a perl executable without C<".">; unsetting this
+option using C<-U> reverts perl to the old behaviour. This may fix your
+path issues but will reintroduce all the security concerns, so don't
+build a perl executable like this unless you're I<really> confident that
+such issues are not a concern in your environment.
+
+=item * C<PERL_USE_UNSAFE_INC>
+
+There is a new environment variable recognised by the perl interpreter.
+If this variable has the value 1 when the perl interpreter starts up,
+then C<"."> will be automatically appended to C<@INC> (except under tainting).
+
+This allows you restore the old perl interpreter behaviour on a
+case-by-case basis. But note that this is intended to be a temporary crutch,
+and this feature will likely be removed in some future perl version.
+It is currently set by the C<cpan> utility and C<Test::Harness> to
+ease installation of CPAN modules which have not been updated to handle the
+lack of dot. Once again, don't use this unless you are sure that this
+will not reintroduce any security concerns.
+
+=item * A new mandatory warning issued by C<do>.
+
+While it is well-known that C<use> and C<require> use C<@INC> to search
+for the file to load, many people don't realise that C<do "file"> also
+searches C<@INC> if the file is a relative path. With the removal of C<".">,
+a simple C<do "file.pl"> will fail to read in and execute C<file.pl> from
+the current directory. Since this is commonly expected behaviour, a new
+mandatory warning is now issued whenever C<do> fails to load a file which
+it otherwise would have found if dot had been in C<@INC>.
+
+=back
+
+Here are some things script and module authors may need to do to make
+their software work in the new regime.
+
+=over
+
+=item * Script authors
+
+If the issue is within your own code (rather than within included
+modules), then you have two main options. Firstly, if you are confident
+that your script will only be run within a trusted directory (under which
+you expect to find trusted files and modules), then add C<"."> back into the
+path; I<e.g.>:
+
+ BEGIN {
+ my $dir = "/some/trusted/directory";
+ chdir $dir or die "Can't chdir to $dir: $!\n";
+ # safe now
+ push @INC, '.';
+ }
+ use "Foo::Bar"; # may load /some/trusted/directory/Foo/Bar.pm
+ do "config.pl"; # may load /some/trusted/directory/config.pl
+
+On the other hand, if your script is intended to be run from within
+untrusted directories (such as F</tmp>), then your script suddenly failing
+to load files may be indicative of a security issue. You most likely want
+to replace any relative paths with full paths; for example,
+
+ do ".foo_config.pl"
+
+might become
+
+ do "$ENV{HOME}/.foo_config.pl"
+
+If you are absolutely certain that you want your script to load and
+execute a file from the current directory, then use a C<./> prefix; for
+example:
+
+ do "./.foo_config.pl"
+
+=item * Installing and using CPAN modules
+
+If you install a CPAN module using an automatic tool like C<cpan>, then
+this tool will itself set the C<PERL_USE_UNSAFE_INC> environment variable
+while building and testing the module, which may be sufficient to install
+a distribution which hasn't been updated to be dot-aware. If you want to
+install such a module manually, then you'll need to replace the
+traditional invocation:
+
+ perl Makefile.PL && make && make test && make install
+
+with something like
+
+ (export PERL_USE_UNSAFE_INC=1; \
+ perl Makefile.PL && make && make test && make install)
+
+Note that this only helps build and install an unfixed module. It's
+possible for the tests to pass (since they were run under
+C<PERL_USE_UNSAFE_INC=1>), but for the module itself to fail to perform
+correctly in production. In this case you may have to temporarily modify
+your script until such time as a fixed version of the module is released.
+For example:
+
+ use Foo::Bar;
+ {
+ local @INC = (@INC, '.');
+ # assuming read_config() needs '.' in @INC
+ $config = Foo::Bar->read_config();
+ }
+
+This is only rarely expected to be necessary. Again, if doing this,
+assess the resultant risks first.
+
+=item * Module Authors
+
+If you maintain a CPAN distribution, it may need updating to run in
+a dotless environment. Although C<cpan> and other such tools will
+currently set the C<PERL_USE_UNSAFE_INC> during module build, this is a
+temporary workaround for the set of modules which rely on C<"."> being in
+C<@INC> for installation and testing, and this may mask deeper issues. It
+could result in a module which passes tests and installs, but which
+fails at run time.
+
+During build, test and install, it will normally be the case that any perl
+processes will be executing directly within the root directory of the
+untarred distribution, or a known subdirectory of that, such as F<t/>. It
+may well be that F<Makefile.PL> or F<t/foo.t> will attempt to include
+local modules and configuration files using their direct relative
+filenames, which will now fail.
+
+However, as described above, automatic tools like F<cpan> will (for now)
+set the C<PERL_USE_UNSAFE_INC> environment variable, which introduces
+dot during build.
+
+This makes it likely that your existing build and test code will work, but
+this may mask issues with your code which only manifest when used after
+install. It is prudent to try and run your build process with that
+variable explicitly disabled:
+
+ (export PERL_USE_UNSAFE_INC=0; \
+ perl Makefile.PL && make && make test && make install)
+
+This is more likely to show up any potential problems with your module's
+build process, or even with the module itself. Fixing such issues will
+ensure both that your module can again be installed manually, and that
+it will still build once the C<PERL_USE_UNSAFE_INC> crutch goes away.
+
+When fixing issues in tests due to the removal of dot from C<@INC>,
+reinsertion of dot into C<@INC> should be performed with caution, for this
+too may suppress real errors in your runtime code. You are encouraged
+wherever possible to apply the aforementioned approaches with explicit
+absolute/relative paths, or to relocate your needed files into a
+subdirectory and insert that subdirectory into C<@INC> instead.
+
+If your runtime code has problems under the dotless C<@INC>, then the comments
+above on how to fix for script authors will mostly apply here too. Bear in
+mind though that it is considered bad form for a module to globally add dot to
+C<@INC>, since it introduces both a security risk and hides issues of
+accidentally requiring dot in C<@INC>, as explained above.
+
+=back
+
+=head2 Escaped colons and relative paths in PATH
+
+On Unix systems, Perl treats any relative paths in the PATH environment
+variable as tainted when starting a new process. Previously, it was
+allowing a backslash to escape a colon (unlike the OS), consequently
+allowing relative paths to be considered safe if the PATH was set to
+something like C</\:.>. The check has been fixed to treat C<"."> as tainted
+in that example.
+
+=head2 C<-Di> switch is now required for PerlIO debugging output
+
+Previously PerlIO debugging output would be sent to the file specified
+by the C<PERLIO_DEBUG> environment variable if perl wasn't running
+setuid and the C<-T> or C<-t> switches hadn't been parsed yet.
+
+If perl performed output at a point where it hadn't yet parsed its
+switches this could result in perl creating or overwriting the file
+named by C<PERLIO_DEBUG> even when the C<-T> switch had been supplied.
+
+Perl now requires the C<-Di> switch to produce PerlIO debugging
+output. By default this is written to C<stderr>, but can optionally
+be redirected to a file by setting the C<PERLIO_DEBUG> environment
+variable.
+
+If perl is running setuid or the C<-T> switch has supplied
+C<PERLIO_DEBUG> is ignored and the debugging output is sent to
+C<stderr> as for any other C<-D> switch.
+
+=head1 Incompatible Changes
+
+=head2 Unescaped literal C<"{"> characters in regular expression
+patterns are no longer permissible
+
+You have to now say something like C<"\{"> or C<"[{]"> to specify to
+match a LEFT CURLY BRACKET; otherwise it is a fatal pattern compilation
+error. This change will allow future extensions to the language.
+
+These have been deprecated since v5.16, with a deprecation message
+raised for some uses starting in v5.22. Unfortunately, the code added
+to raise the message was buggy, and failed to warn in some cases where
+it should have. Therefore, enforcement of this ban for these cases is
+deferred until Perl 5.30, but the code has been fixed to raise a
+default-on deprecation message for them in the meantime.
+
+Some uses of literal C<"{"> occur in contexts where we do not foresee
+the meaning ever being anything but the literal, such as the very first
+character in the pattern, or after a C<"|"> meaning alternation. Thus
+
+ qr/{fee|{fie/
+
+matches either of the strings C<{fee> or C<{fie>. To avoid forcing
+unnecessary code changes, these uses do not need to be escaped, and no
+warning is raised about them, and there are no current plans to change this.
+
+But it is always correct to escape C<"{">, and the simple rule to
+remember is to always do so.
+
+=head2 C<scalar(%hash)> return signature changed
+
+The value returned for C<scalar(%hash)> will no longer show information about
+the buckets allocated in the hash. It will simply return the count of used
+keys. It is thus equivalent to C<0+keys(%hash)>.
+
+A form of backwards compatibility is provided via
+L<C<Hash::Util::bucket_ratio()>|Hash::Util/bucket_ratio> which provides
+the same behavior as
+C<scalar(%hash)> provided in Perl 5.24 and earlier.
+
+=head2 C<keys> returned from an lvalue subroutine
+
+C<keys> returned from an lvalue subroutine can no longer be assigned
+to in list context.
+
+ sub foo : lvalue { keys(%INC) }
+ (foo) = 3; # death
+ sub bar : lvalue { keys(@_) }
+ (bar) = 3; # also an error
+
+This makes the lvalue sub case consistent with C<(keys %hash) = ...> and
+C<(keys @_) = ...>, which are also errors. [perl #128187]
+
+=head2 C<${^ENCODING}> has been removed
+
+Consequently, the L<encoding> pragma's default mode is no longer supported. If
+you still need to write your source code in encodings other than UTF-8, use a
+source filter such as L<Filter::Encoding> on CPAN or L<encoding>'s C<Filter>
+option.
+
+=head2 C<POSIX::tmpnam()> has been removed
+
+The fundamentally unsafe C<tmpnam()> interface was deprecated in
+Perl 5.22 and has now been removed. In its place you can use,
+for example, the L<File::Temp> interfaces.
+
+=head2 require ::Foo::Bar is now illegal.
+
+Formerly, C<require ::Foo::Bar> would try to read F</Foo/Bar.pm>. Now any
+bareword require which starts with a double colon dies instead.
+
+=head2 Literal control character variable names are no longer permissible
+
+A variable name may no longer contain a literal control character under
+any circumstances. These previously were allowed in single-character
+names on ASCII platforms, but have been deprecated there since Perl
+5.20. This affects things like C<$I<\cT>>, where I<\cT> is a literal
+control (such as a C<NAK> or C<NEGATIVE ACKNOWLEDGE> character) in the
+source code.
+
+=head2 C<NBSP> is no longer permissible in C<\N{...}>
+
+The name of a character may no longer contain non-breaking spaces. It
+has been deprecated to do so since Perl 5.22.
+
+=head1 Deprecations
+
+=head2 String delimiters that aren't stand-alone graphemes are now deprecated
+
+In order for Perl to eventually allow string delimiters to be Unicode
+grapheme clusters (which look like a single character, but may be
+a sequence of several ones), we have to stop allowing a single character
+delimiter that isn't a grapheme by itself. These are unlikely to exist
+in actual code, as they would typically display as attached to the
+character in front of them.
+
+=head2 C<\cI<X>> that maps to a printable is no longer deprecated
+
+This means we have no plans to remove this feature. It still raises a
+warning, but only if syntax warnings are enabled. The feature was
+originally intended to be a way to express non-printable characters that
+don't have a mnemonic (C<\t> and C<\n> are mnemonics for two
+non-printable characters, but most non-printables don't have a
+mnemonic.) But the feature can be used to specify a few printable
+characters, though those are more clearly expressed as the printable
+itself. See
+L<http://www.nntp.perl.org/group/perl.perl5.porters/2017/02/msg242944.html>.
+
+=head1 Performance Enhancements
+
+=over 4
+
+=item *
+
+A hash in boolean context is now sometimes faster, I<e.g.>
+
+ if (!%h) { ... }
+
+This was already special-cased, but some cases were missed (such as
+C<grep %$_, @AoH>, and even the ones which weren't have been improved.
+
+=item * New Faster Hash Function on 64 bit builds
+
+We use a different hash function for short and long keys. This should
+improve performance and security, especially for long keys.
+
+=item * readline is faster
+
+Reading from a file line-by-line with C<readline()> or C<< E<lt>E<gt> >> should
+now typically be faster due to a better implementation of the code that
+searches for the next newline character.
+
+=item *
+
+Reduce cost of C<SvVALID()>.
+
+=item *
+
+C<$ref1 = $ref2> has been optimized.
+
+=item *
+
+Array and hash assignment are now faster, I<e.g.>
+
+ (..., @a) = (...);
+ (..., %h) = (...);
+
+especially when the RHS is empty.
+
+=item *
+
+Reduce the number of odd special cases for the C<SvSCREAM> flag.
+
+=item *
+
+Avoid C<sv_catpvn()> in C<do_vop()> when unneeded.
+
+=item *
+
+Enhancements in Regex concat COW implementation.
+
+=item *
+
+Better optimise array and hash assignment: where an array or hash appears
+in the LHS of a list assignment, such as C<(..., @a) = (...);>, it's
+likely to be considerably faster, especially if it involves emptying the
+array/hash. For example this code runs about 1/3 faster compared to
+Perl 5.24.0:
+
+ my @a;
+ for my $i (1..10_000_000) {
+ @a = (1,2,3);
+ @a = ();
+ }
+
+
+=item *
+
+Converting a single-digit string to a number is now substantially faster.
+
+=item *
+
+The internal op implementing the C<split> builtin has been simplified and
+sped up. Firstly, it no longer requires a subsidiary internal C<pushre> op
+to do its work. Secondly, code of the form C<my @x = split(...)> is now
+optimised in the same way as C<@x = split(...)>, and is therefore a few
+percent faster.
+
+=item *
+
+The rather slow implementation for the experimental subroutine signatures
+feature has been made much faster; it is now comparable in speed with the
+old-style C<my ($a, $b, @c) = @_>.
+
+=item *
+
+Bareword constant strings are now permitted to take part in constant
+folding. They were originally exempted from constant folding in August 1999,
+during the development of Perl 5.6, to ensure that C<use strict "subs">
+would still apply to bareword constants. That has now been accomplished a
+different way, so barewords, like other constants, now gain the performance
+benefits of constant folding.
+
+This also means that void-context warnings on constant expressions of
+barewords now report the folded constant operand, rather than the operation;
+this matches the behaviour for non-bareword constants.
+
+=back
=head1 Modules and Pragmata
-=head2 Updated Modules and Pragmata
+=head2 Updated Modules and Pragmata
+
+=over 4
+
+=item *
+
+L<Archive::Tar> has been upgraded from version 2.04 to 2.24.
+
+=item *
+
+L<arybase> has been upgraded from version 0.11 to 0.12.
+
+=item *
+
+L<attributes> has been upgraded from version 0.27 to 0.29.
+
+The deprecation message for the C<:unique> and C<:locked> attributes
+now mention that they will disappear in Perl 5.28.
+
+=item *
+
+L<B> has been upgraded from version 1.62 to 1.68.
+
+=item *
+
+L<B::Concise> has been upgraded from version 0.996 to 0.999.
+
+Its output is now more descriptive for C<op_private> flags.
+
+=item *
+
+L<B::Debug> has been upgraded from version 1.23 to 1.24.
+
+=item *
+
+L<B::Deparse> has been upgraded from version 1.37 to 1.40.
+
+=item *
+
+L<B::Xref> has been upgraded from version 1.05 to 1.06.
+
+It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
+
+=item *
+
+L<base> has been upgraded from version 2.23 to 2.25.
+
+=item *
+
+L<bignum> has been upgraded from version 0.42 to 0.47.
+
+=item *
+
+L<Carp> has been upgraded from version 1.40 to 1.42.
+
+=item *
+
+L<charnames> has been upgraded from version 1.43 to 1.44.
+
+=item *
+
+L<Compress::Raw::Bzip2> has been upgraded from version 2.069 to 2.074.
+
+=item *
+
+L<Compress::Raw::Zlib> has been upgraded from version 2.069 to 2.074.
+
+=item *
+
+L<Config::Perl::V> has been upgraded from version 0.25 to 0.28.
+
+=item *
+
+L<CPAN> has been upgraded from version 2.11 to 2.18.
+
+=item *
+
+L<CPAN::Meta> has been upgraded from version 2.150005 to 2.150010.
+
+=item *
+
+L<Data::Dumper> has been upgraded from version 2.160 to 2.167.
+
+The XS implementation now supports Deparse.
+
+This fixes a stack management bug. [perl #130487].
+
+=item *
+
+L<DB_File> has been upgraded from version 1.835 to 1.840.
+
+=item *
+
+L<Devel::Peek> has been upgraded from version 1.23 to 1.26.
+
+=item *
+
+L<Devel::PPPort> has been upgraded from version 3.32 to 3.35.
+
+=item *
+
+L<Devel::SelfStubber> has been upgraded from version 1.05 to 1.06.
+
+It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
+
+=item *
+
+L<diagnostics> has been upgraded from version 1.34 to 1.36.
+
+It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
+
+=item *
+
+L<Digest> has been upgraded from version 1.17 to 1.17_01.
+
+=item *
+
+L<Digest::MD5> has been upgraded from version 2.54 to 2.55.
+
+=item *
+
+L<Digest::SHA> has been upgraded from version 5.95 to 5.96.
+
+=item *
+
+L<DynaLoader> has been upgraded from version 1.38 to 1.42.
+
+=item *
+
+L<Encode> has been upgraded from version 2.80 to 2.88.
+
+=item *
+
+L<encoding> has been upgraded from version 2.17 to 2.19.
+
+This module's default mode is no longer supported. It now
+dies when imported, unless the C<Filter> option is being used.
+
+=item *
+
+L<encoding::warnings> has been upgraded from version 0.12 to 0.13.
+
+This module is no longer supported. It emits a warning to
+that effect and then does nothing.
+
+=item *
+
+L<Errno> has been upgraded from version 1.25 to 1.28.
+
+Document that using C<%!> loads Errno for you.
+
+It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
+
+=item *
+
+L<ExtUtils::Embed> has been upgraded from version 1.33 to 1.34.
+
+It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
+
+=item *
+
+L<ExtUtils::MakeMaker> has been upgraded from version 7.10_01 to 7.24.
+
+=item *
+
+L<ExtUtils::Miniperl> has been upgraded from version 1.05 to 1.06.
+
+=item *
+
+L<ExtUtils::ParseXS> has been upgraded from version 3.31 to 3.34.
+
+=item *
+
+L<ExtUtils::Typemaps> has been upgraded from version 3.31 to 3.34.
+
+=item *
+
+L<feature> has been upgraded from version 1.42 to 1.47.
+
+Fixes the Unicode Bug in the range operator.
+
+=item *
+
+L<File::Copy> has been upgraded from version 2.31 to 2.32.
+
+=item *
+
+L<File::Fetch> has been upgraded from version 0.48 to 0.52.
+
+=item *
+
+L<File::Glob> has been upgraded from version 1.26 to 1.28.
+
+Issue a deprecation message for C<File::Glob::glob()>.
+
+=item *
+
+L<File::Spec> has been upgraded from version 3.63 to 3.67.
+
+=item *
+
+L<FileHandle> has been upgraded from version 2.02 to 2.03.
+
+=item *
+
+L<Filter::Simple> has been upgraded from version 0.92 to 0.93.
+
+It no longer treats C<no MyFilter> immediately following C<use MyFilter> as
+end-of-file. [perl #107726]
+
+=item *
+
+L<Getopt::Long> has been upgraded from version 2.48 to 2.49.
+
+=item *
+
+L<Getopt::Std> has been upgraded from version 1.11 to 1.12.
+
+=item *
+
+L<Hash::Util> has been upgraded from version 0.19 to 0.22.
+
+=item *
+
+L<HTTP::Tiny> has been upgraded from version 0.056 to 0.070.
+
+Internal 599-series errors now include the redirect history.
+
+=item *
+
+L<I18N::LangTags> has been upgraded from version 0.40 to 0.42.
+
+It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
+
+=item *
+
+L<IO> has been upgraded from version 1.36 to 1.38.
+
+=item *
+
+IO-Compress has been upgraded from version 2.069 to 2.074.
+
+=item *
+
+L<IO::Socket::IP> has been upgraded from version 0.37 to 0.38.
+
+=item *
+
+L<IPC::Cmd> has been upgraded from version 0.92 to 0.96.
+
+=item *
+
+L<IPC::SysV> has been upgraded from version 2.06_01 to 2.07.
+
+=item *
+
+L<JSON::PP> has been upgraded from version 2.27300 to 2.27400_02.
+
+=item *
+
+L<lib> has been upgraded from version 0.63 to 0.64.
+
+It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
+
+=item *
+
+L<List::Util> has been upgraded from version 1.42_02 to 1.46_02.
+
+=item *
+
+L<Locale::Codes> has been upgraded from version 3.37 to 3.42.
+
+=item *
+
+L<Locale::Maketext> has been upgraded from version 1.26 to 1.28.
+
+=item *
+
+L<Locale::Maketext::Simple> has been upgraded from version 0.21 to 0.21_01.
+
+=item *
+
+L<Math::BigInt> has been upgraded from version 1.999715 to 1.999806.
+
+There have also been some core customizations.
+
+=item *
+
+L<Math::BigInt::FastCalc> has been upgraded from version 0.40 to 0.5005.
+
+=item *
+
+L<Math::BigRat> has been upgraded from version 0.260802 to 0.2611.
+
+=item *
+
+L<Math::Complex> has been upgraded from version 1.59 to 1.5901.
+
+=item *
+
+L<Memoize> has been upgraded from version 1.03 to 1.03_01.
+
+=item *
+
+L<Module::CoreList> has been upgraded from version 5.20170420 to 5.20170520.
+
+=item *
+
+L<Module::Load::Conditional> has been upgraded from version 0.64 to 0.68.
+
+=item *
+
+L<Module::Metadata> has been upgraded from version 1.000031 to 1.000033.
+
+=item *
+
+L<mro> has been upgraded from version 1.18 to 1.20.
+
+=item *
+
+L<Net::Ping> has been upgraded from version 2.43 to 2.55.
+
+IPv6 addresses and C<AF_INET6> sockets are now supported, along with several
+other enhancements.
+
+Remove sudo from 500_ping_icmp.t.
+
+Avoid stderr noise in tests
+
+Check for echo in new L<Net::Ping> tests.
+
+=item *
+
+L<NEXT> has been upgraded from version 0.65 to 0.67.
+
+=item *
+
+L<Opcode> has been upgraded from version 1.34 to 1.39.
+
+=item *
+
+L<open> has been upgraded from version 1.10 to 1.11.
+
+=item *
+
+L<OS2::Process> has been upgraded from version 1.11 to 1.12.
+
+It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
+
+=item *
+
+L<overload> has been upgraded from version 1.26 to 1.28.
+
+Its compilation speed has been improved slightly.
+
+=item *
+
+L<parent> has been upgraded from version 0.234 to 0.236.
+
+=item *
+
+L<perl5db.pl> has been upgraded from version 1.50 to 1.51.
+
+Ignore F</dev/tty> on non-Unix systems. [perl #113960]
+
+=item *
+
+L<Perl::OSType> has been upgraded from version 1.009 to 1.010.
+
+=item *
+
+L<perlfaq> has been upgraded from version 5.021010 to 5.021011.
+
+=item *
+
+L<PerlIO> has been upgraded from version 1.09 to 1.10.
+
+=item *
+
+L<PerlIO::encoding> has been upgraded from version 0.24 to 0.25.
+
+=item *
+
+L<PerlIO::scalar> has been upgraded from version 0.24 to 0.26.
+
+=item *
+
+L<Pod::Checker> has been upgraded from version 1.60 to 1.73.
+
+=item *
+
+L<Pod::Functions> has been upgraded from version 1.10 to 1.11.
+
+=item *
+
+L<Pod::Html> has been upgraded from version 1.22 to 1.2202.
+
+=item *
+
+L<Pod::Perldoc> has been upgraded from version 3.25_02 to 3.28.
+
+=item *
+
+L<Pod::Simple> has been upgraded from version 3.32 to 3.35.
+
+=item *
+
+L<Pod::Usage> has been upgraded from version 1.68 to 1.69.
+
+=item *
+
+L<POSIX> has been upgraded from version 1.65 to 1.76. This remedies several
+defects in making its symbols exportable. [perl #127821]
+The C<POSIX::tmpnam()> interface has been removed,
+see L</"POSIX::tmpnam() has been removed">.
+Trying to import POSIX subs that have no real implementations
+(like C<POSIX::atend()>) now fails at import time, instead of
+waiting until runtime.
+
+=item *
+
+L<re> has been upgraded from version 0.32 to 0.34
+
+This adds support for the new L<C<E<47>xx>|perlre/E<sol>x and E<sol>xx>
+regular expression pattern modifier, and a change to the L<S<C<use re
+'strict'>>|re/'strict' mode> experimental feature. When S<C<re
+'strict'>> is enabled, a warning now will be generated for all
+unescaped uses of the two characters C<"}"> and C<"]"> in regular
+expression patterns (outside bracketed character classes) that are taken
+literally. This brings them more in line with the C<")"> character which
+is always a metacharacter unless escaped. Being a metacharacter only
+sometimes, depending on action at a distance, can lead to silently
+having the pattern mean something quite different than was intended,
+which the S<C<re 'strict'>> mode is intended to minimize.
+
+=item *
+
+L<Safe> has been upgraded from version 2.39 to 2.40.
+
+=item *
+
+L<Scalar::Util> has been upgraded from version 1.42_02 to 1.46_02.
+
+=item *
+
+L<Storable> has been upgraded from version 2.56 to 2.62.
+
+Fixes [perl #130098].
+
+=item *
+
+L<Symbol> has been upgraded from version 1.07 to 1.08.
+
+=item *
+
+L<Sys::Syslog> has been upgraded from version 0.33 to 0.35.
+
+=item *
+
+L<Term::ANSIColor> has been upgraded from version 4.04 to 4.06.
+
+=item *
+
+L<Term::ReadLine> has been upgraded from version 1.15 to 1.16.
+
+It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
+
+=item *
+
+L<Test> has been upgraded from version 1.28 to 1.30.
+
+It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
+
+=item *
+
+L<Test::Harness> has been upgraded from version 3.36 to 3.38.
+
+=item *
+
+L<Test::Simple> has been upgraded from version 1.001014 to 1.302073.
+
+=item *
+
+L<Thread::Queue> has been upgraded from version 3.09 to 3.12.
+
+=item *
+
+L<Thread::Semaphore> has been upgraded from 2.12 to 2.13.
+
+Added the C<down_timed> method.
+
+=item *
+
+L<threads> has been upgraded from version 2.07 to 2.15.
+
+Compatibility with 5.8 has been restored.
+
+Fixes [perl #130469].
+
+=item *
+
+L<threads::shared> has been upgraded from version 1.51 to 1.56.
+
+This fixes [cpan #119529], [perl #130457]
+
+=item *
+
+L<Tie::Hash::NamedCapture> has been upgraded from version 0.09 to 0.10.
+
+=item *
+
+L<Time::HiRes> has been upgraded from version 1.9733 to 1.9741.
+
+It now builds on systems with C++11 compilers (such as G++ 6 and Clang++
+3.9).
+
+Now uses C<clockid_t>.
+
+=item *
+
+L<Time::Local> has been upgraded from version 1.2300 to 1.25.
+
+=item *
+
+L<Unicode::Collate> has been upgraded from version 1.14 to 1.19.
+
+=item *
+
+L<Unicode::UCD> has been upgraded from version 0.64 to 0.68.
+
+It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
+
+=item *
+
+L<version> has been upgraded from version 0.9916 to 0.9917.
+
+=item *
+
+L<VMS::DCLsym> has been upgraded from version 1.06 to 1.08.
+
+It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
+
+=item *
+
+L<warnings> has been upgraded from version 1.36 to 1.37.
+
+=item *
+
+L<XS::Typemap> has been upgraded from version 0.14 to 0.15.
+
+=item *
+
+L<XSLoader> has been upgraded from version 0.21 to 0.27.
+
+Fixed a security hole in which binary files could be loaded from a path
+outside of L<C<@INC>|perlvar/@INC>.
+
+It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
+
+=back
+
+=head1 Documentation
+
+=head2 New Documentation
+
+=head3 L<perldeprecation>
+
+This file documents all upcoming deprecations, and some of the deprecations
+which already have been removed. The purpose of this documentation is
+two-fold: document what will disappear, and by which version, and serve
+as a guide for people dealing with code which has features that no longer
+work after an upgrade of their perl.
+
+=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, send email to
+L<perlbug@perl.org|mailto:perlbug@perl.org>.
+
+Additionally all references to Usenet have been removed, and the
+following selected changes have been made:
+
+=head3 L<perlfunc>
+
+=over 4
+
+=item *
+
+Removed obsolete text about L<C<defined()>|perlfunc/defined>
+on aggregates that should have been deleted earlier, when the feature
+was removed.
+
+=item *
+
+Corrected documentation of L<C<eval()>|perlfunc/eval>,
+and L<C<evalbytes()>|perlfunc/evalbytes>.
+
+=item *
+
+Clarified documentation of L<C<seek()>|perlfunc/seek>,
+L<C<tell()>|perlfunc/tell> and L<C<sysseek()>|perlfunc/sysseek>
+emphasizing that positions are in bytes and not characters.
+L<[perl #128607]|https://rt.perl.org/Public/Bug/Display.html?id=128607>
+
+=item *
+
+Clarified documentation of L<C<sort()>|perlfunc/sort LIST> concerning
+the variables C<$a> and C<$b>.
+
+=item *
+
+In L<C<split()>|perlfunc/split> noted that certain pattern modifiers are
+legal, and added a caution about its use in Perls before v5.11,
+
+=item *
+
+Removed obsolete documentation of L<C<study()>|perlfunc/study>, noting
+that it is now a no-op.
+
+=item *
+
+Noted that L<C<vec()>|perlfunc/vec> doesn't work well when the string
+contains characters whose code points are above 255.
+
+=back
+
+=head3 L<perlguts>
+
+=over 4
+
+=item *
+
+Added advice on
+L<formatted printing of operands of C<Size_t> and C<SSize_t>|perlguts/Formatted Printing of Size_t and SSize_t>
+
+=back
+
+=head3 L<perlhack>
+
+=over 4
+
+=item *
+
+Clarify what editor tab stop rules to use, and note that we are
+migrating away from using tabs, replacing them with sequences of SPACE
+characters.
+
+=back
+
+=head3 L<perlhacktips>
+
+=over 4
+
+=item *
+
+Give another reason to use C<cBOOL> to cast an expression to boolean.
+
+=item *
+
+Note that there are macros C<TRUE> and C<FALSE> available to express
+boolean values.
+
+=back
+
+=head3 L<perlinterp>
+
+=over 4
+
+=item *
+
+L<perlinterp> has been expanded to give a more detailed example of how to
+hunt around in the parser for how a given operator is handled.
+
+=back
+
+=head3 L<perllocale>
+
+=over 4
+
+=item *
+
+Some locales aren't compatible with Perl. Note that these can cause
+core dumps.
+
+=back
+
+=head3 L<perlmodinstall>
+
+=over 4
+
+=item *
+
+Various clarifications have been added.
+
+=back
+
+=head3 L<perlmodlib>
+
+=over 4
+
+=item *
+
+Updated the site mirror list.
+
+=back
+
+=head3 L<perlobj>
+
+=over 4
+
+=item *
+
+Added a section on calling methods using their fully qualified names.
+
+=item *
+
+Do not discourage manual C<@ISA>.
+
+=back
+
+=head3 L<perlootut>
+
+=over 4
+
+=item *
+
+Mention C<Moo> more.
+
+=back
+
+=head3 L<perlop>
+
+=over 4
+
+=item *
+
+Clarify behavior of single quote regexps.
+
+=back
+
+=head3 L<perlre>
+
+=over 4
+
+=item *
+
+The first part was extensively rewritten to incorporate various basic
+points, that in earlier versions were mentioned in sort of an appendix
+on Version 8 regular expressions.
+
+=item *
+
+Note that it is common to have the C</x> modifier and forget that this
+means that C<"#"> has to be escaped.
+
+=back
+
+=head3 L<perlretut>
+
+=over 4
+
+=item *
+
+Add introductory material
+
+=item *
+
+Note that a metacharacter occurring in a context where it can't mean
+that, silently loses its meta-ness and matches literally.
+L<C<use re 'strict'>|re/'strict' mode> can catch some of these.
+
+=back
+
+=head3 L<perlunicode>
+
+=over 4
+
+=item *
+
+Corrected the text about Unicode BYTE ORDER MARK handling.
+
+=item *
+
+Updated the text to correspond with changes in Unicode UTS#18, concerning
+regular expressions, and Perl compatibility with what it says.
+
+=back
+
+=head3 L<perlvar>
+
+=over 4
+
+=item *
+
+Document C<@ISA>. Was documented other places, not not in L<perlvar>.
+
+=back
+
+=head1 Diagnostics
+
+=head2 New Diagnostics
+
+=head3 New Errors
+
+=over 4
+
+=item *
+
+Since C<"."> is now removed from C<@INC> by default, C<do> will now trigger
+a warning recommending to fix the C<do> statement:
+
+L<do "%s" failed, '.' is no longer in @INC|perldiag/do "%s" failed, '.' is no longer in @INC; did you mean do ".E<sol>%s"?>
+
+=item *
+
+Using the empty pattern (which re-executes the last successfully-matched
+pattern) inside a code block in another regex, as in C</(?{ s!!new! })/>, has
+always previously yielded a segfault. It now produces an error:
+L<Infinite recursion in regex|perldiag/"Infinite recursion in regex">.
+
+=item *
+
+L<The experimental declared_refs feature is not enabled|perldiag/"The experimental declared_refs feature is not enabled">
+
+(F) To declare references to variables, as in C<my \%x>, you must first enable
+the feature:
+
+ no warnings "experimental::declared_refs";
+ use feature "declared_refs";
+
+=item *
+
+L<Version control conflict marker|perldiag/"Version control conflict marker">
+
+(F) The parser found a line starting with C<E<lt>E<lt>E<lt>E<lt>E<lt>E<lt>E<lt>>,
+C<E<gt>E<gt>E<gt>E<gt>E<gt>E<gt>E<gt>>, or C<=======>. These may be left by a
+version control system to mark conflicts after a failed merge operation.
+
+=item *
+
+L<%s: command not found|perldiag/"%s: command not found">
+
+(A) You've accidentally run your script through B<bash> or another shell
+instead of Perl. Check the #! line, or manually feed your script into
+Perl yourself. The #! line at the top of your file could look like:
+
+ #!/usr/bin/perl
+
+=item *
+
+L<%s: command not found: %s|perldiag/"%s: command not found: %s">
+
+(A) You've accidentally run your script through B<zsh> or another shell
+instead of Perl. Check the #! line, or manually feed your script into
+Perl yourself. The #! line at the top of your file could look like:
+
+ #!/usr/bin/perl
+
+=item *
+
+L<Unescaped left brace in regex is illegal here|perldiag/Unescaped left brace in regex is illegal here in regex; marked by S<E<lt>-- HERE> in mE<sol>%sE<sol>>
+
+Unescaped left braces are now illegal in some contexts in regular expression
+patterns. In other contexts, they are still just deprecated; they will
+be illegal in Perl 5.30.
+
+=item *
+
+L<Bareword in require contains "%s"|perldiag/"Bareword in require contains "%s"">
+
+=item *
+
+L<Bareword in require maps to empty filename|perldiag/"Bareword in require maps to empty filename">
+
+=item *
+
+L<Bareword in require maps to disallowed filename "%s"|perldiag/"Bareword in require maps to disallowed filename "%s"">
+
+=item *
+
+L<Bareword in require must not start with a double-colon: "%s"|perldiag/"Bareword in require must not start with a double-colon: "%s"">
+
+=back
+
+=head3 New Warnings
+
+=over 4
+
+=item *
+
+L<Use of unassigned code point or non-standalone grapheme for a delimiter will be a fatal error starting in Perl 5.30|perldiag/"Use of unassigned code point or non-standalone grapheme for a delimiter will be a fatal error starting in Perl 5.30">
+
+See L</Deprecations>
+
+=item *
+
+L<Declaring references is experimental|perldiag/"Declaring references is experimental">
+
+(S experimental::declared_refs) This warning is emitted if you use a reference
+constructor on the right-hand side of C<my()>, C<state()>, C<our()>, or
+C<local()>. Simply suppress the warning if you want to use the feature, but
+know that in doing so you are taking the risk of using an experimental feature
+which may change or be removed in a future Perl version:
+
+ no warnings "experimental::declared_refs";
+ use feature "declared_refs";
+ $fooref = my \$foo;
+
+=item *
+
+L<C<${^ENCODING}> is no longer supported. Its use will be fatal in Perl 5.28|perldiag/"${^ENCODING} is no longer supported. Its use will be fatal in Perl 5.28">
+
+The special variable C<${^ENCODING}>, formerly used to implement
+the C<encoding> pragma, is no longer supported as of Perl 5.26.
+
+=item *
+
+Since C<"."> is now removed from C<@INC> by default, C<do> will now trigger
+a warning recommending to fix the C<do> statement:
+
+L<do "%s" failed, '.' is no longer in @INC|perldiag/do "%s" failed, '.' is no longer in @INC; did you mean do ".E<sol>%s"?>
+
+=back
+
+=head2 Changes to Existing Diagnostics
+
+=over 4
+
+=item *
+
+When a C<require> fails, we now do not provide C<@INC> when the C<require>
+is for a file instead of a module.
+
+=item *
+
+When C<@INC> is not scanned for a C<require> call, we no longer display
+C<@INC> to avoid confusion.
+
+=item *
+
+Attribute "locked" is deprecated, and will disappear in Perl 5.28
+
+=item *
+
+Attribute "unique" is deprecated, and will disappear in Perl 5.28
+
+=item *
+
+Constants from lexical variables potentially modified elsewhere are
+deprecated. This will not be allowed in Perl 5.32
+
+=item *
+
+Deprecated use of C<my()> in false conditional. This will be a fatal error
+in Perl 5.30
+
+=item *
+
+C<dump()> better written as C<CORE::dump()>. C<dump()> will no longer be available
+in Perl 5.30
+
+=item *
+
+${^ENCODING} is no longer supported. Its use will be fatal in Perl 5.28
+
+=item *
+
+File::Glob::glob() will disappear in perl 5.30. Use File::Glob::bsd_glob()
+instead.
+
+=item *
+
+%s() is deprecated on :utf8 handles. This will be a fatal error in Perl 5.30
+
+=item *
+
+$* is no longer supported. Its use will be fatal in Perl 5.30
+
+=item *
+
+$* is no longer supported. Its use will be fatal in Perl 5.30
+
+=item *
+
+Opening dirhandle %s also as a file. This will be a fatal error in Perl 5.28
+
+=item *
+
+Opening filehandle %s also as a directory. This will be a fatal
+error in Perl 5.28
+
+=item *
+
+Setting C<$/> to a reference to %s as a form of slurp is deprecated,
+treating as undef. This will be fatal in Perl 5.28
+
+=item *
+
+Unescaped left brace in regex is deprecated here (and will be fatal
+in Perl 5.30), passed through in regex; marked by S<< E<lt>-- HERE >> in m/%s/
+
+=item *
+
+Unknown charname '' is deprecated. Its use will be fatal in Perl 5.28
+
+=item *
+
+Use of bare E<lt>E<lt> to mean E<lt>E<lt>"" is deprecated. Its use will be fatal in Perl 5.28
+
+=item *
+
+Use of code point 0x%s is deprecated; the permissible max is 0x%s.
+This will be fatal in Perl 5.28
+
+=item *
+
+Use of comma-less variable list is deprecated. Its use will be fatal
+in Perl 5.28
+
+=item *
+
+Use of inherited AUTOLOAD for non-method %s() is deprecated. This
+will be fatal in Perl 5.28
+
+=item *
+
+Use of strings with code points over 0xFF as arguments to %s operator
+is deprecated. This will be a fatal error in Perl 5.28
+
+=item *
+
+Improve error for missing C<tie()> package/method. This brings the error messages
+in line with the ones used for normal method calls, despite not using
+call_method().
+
+=item *
+
+Make the C<sysread()>/C<syswrite()> I<etc.>, C<:utf8> handle warnings
+XXX default. These warnings were under 'deprecated' previously.
+
+=item *
+
+C<do> errors now refer to C<do> (not C<require>).
+
+=item *
+
+Details as to the exact problem have been added to the diagnostics that
+occur when malformed UTF-8 is encountered when trying to convert to a
+code point.
+
+=item *
+
+Executing C<undef $x> where C<$x> is tied or magical no longer incorrectly
+blames the variable for an uninitialized-value warning encountered by the
+tied/magical code.
+
+=item *
+
+Code like C<$x = $x . "a"> was incorrectly failing to yield a
+L<use of uninitialized value|perldiag/"Use of uninitialized value%s">
+warning when C<$x> was a lexical variable with an undefined value. That has
+now been fixed. [perl #127877]
+
+=item *
+
+When the error "Experimental push on scalar is now forbidden" is raised for
+the hash functions C<keys>, C<each>, and C<values>, it is now followed by
+the more helpful message, "Type of arg 1 to whatever must be hash or
+array". [perl #127976]
+
+=item *
+
+C<undef *_; shift> or C<undef *_; pop> inside a subroutine, with no
+argument to C<shift> or C<pop>, began crashing in Perl 5.14, but has now
+been fixed.
+
+=item *
+
+C<< "string$scalar-E<gt>$*" >> now correctly prefers concat overloading to
+string overloading if C<< $scalar-E<gt>$* >> returns an overloaded object,
+bringing it into consistency with C<$$scalar>.
+
+=item *
+
+C<< /@0{0*-E<gt>@*/*0 >> and similar contortions used to crash, but no longer
+do, but merely produce a syntax error. [perl #128171]
+
+=item *
+
+C<do> or C<require> with a reference or typeglob which, when stringified,
+contains a null character started crashing in Perl 5.20, but has now been
+fixed. [perl #128182]
+
+=back
+
+=head1 Utility Changes
+
+=head2 F<c2ph> and F<pstruct>
+
+=over 4
+
+=item *
+
+These old utilities have long since superceded by L<h2xs>, and are
+now gone from the distribution.
+
+=back
+
+=head2 F<Porting/pod_lib.pl>
+
+=over 4
+
+=item *
+
+Removed spurious executable bit.
+
+=item *
+
+Account for the possibility of DOS file endings.
+
+=back
+
+=head2 F<Porting/sync-with-cpan>
+
+=over 4
+
+=item *
+
+Many improvements
+
+=back
+
+=head2 F<perf/benchmarks>
+
+=over 4
+
+=item *
+
+Tidy file, rename some symbols.
+
+=back
+
+=head2 F<Porting/checkAUTHORS.pl>
+
+=over 4
+
+=item *
+
+Replace obscure character range with C<\w>.
+
+=back
+
+=head2 F<t/porting/regen.t>
+
+=over 4
+
+=item *
+
+try to be more helpful when tests fail.
+
+=back
+
+=head2 F<utils/h2xs.PL>
+
+=over 4
+
+=item *
+
+Avoid infinite loop for enums.
+
+=back
+
+=head2 L<perlbug>
+
+=over 4
+
+=item *
+
+Long lines in the message body are now wrapped at 900 characters, to stay
+well within the 1000-character limit imposed by SMTP mail transfer agents.
+This is particularly likely to be important for the list of arguments to
+C<Configure>, which can readily exceed the limit if, for example, it names
+several non-default installation paths. This change also adds the first unit
+tests for perlbug. [perl #128020]
+
+=back
+
+=head1 Configuration and Compilation
+
+=over 4
+
+=item *
+
+C<-Ddefault_inc_excludes_dot> has been turned on by default.
+
+=item *
+
+The C<dtrace> build process has further changes [perl #130108]:
+
+=over
+
+=item *
+
+If the C<-xnolibs> is available, use that so a F<dtrace> perl can be
+built within a FreeBSD jail.
+
+=item *
+
+On systems that build a dtrace object file (FreeBSD, Solaris and
+SystemTap's dtrace emulation), copy the input objects to a separate
+directory and process them there, and use those objects in the link,
+since C<dtrace -G> also modifies these objects.
+
+=item *
+
+Add libelf to the build on FreeBSD 10.x, since dtrace adds references
+to libelf symbols.
+
+=item *
+
+Generate a dummy dtrace_main.o if C<dtrace -G> fails to build it. A
+default build on Solaris generates probes from the unused inline
+functions, while they don't on FreeBSD, which causes C<dtrace -G> to
+fail.
+
+=back
+
+=item *
+
+You can now disable perl's use of the C<PERL_HASH_SEED> and
+C<PERL_PERTURB_KEYS> environment variables by configuring perl with
+C<-Accflags=NO_PERL_HASH_ENV>.
+
+=item *
+
+You can now disable perl's use of the C<PERL_HASH_SEED_DEBUG> environment
+variable by configuring perl with
+C<-Accflags=-DNO_PERL_HASH_SEED_DEBUG>.
+
+=item *
+
+Zero out the alignment bytes when calculating the bytes for 80-bit C<NaN>
+and C<Inf> to make builds more reproducible. [perl #130133]
+
+=item *
+
+Since v5.18 for testing purposes, we have included support for
+building perl with a variety of non-standard, and non-recommended
+hash functions. Since we do not recommend the use of these functions
+we have removed them and their corresponding build options. Specifically
+this includes the following build options:
+
+ PERL_HASH_FUNC_SDBM
+ PERL_HASH_FUNC_DJB2
+ PERL_HASH_FUNC_SUPERFAST
+ PERL_HASH_FUNC_MURMUR3
+ PERL_HASH_FUNC_ONE_AT_A_TIME
+ PERL_HASH_FUNC_ONE_AT_A_TIME_OLD
+ PERL_HASH_FUNC_MURMUR_HASH_64A
+ PERL_HASH_FUNC_MURMUR_HASH_64B
+
+=item *
+
+Remove "Warning: perl appears in your path"
+
+This install warning is more or less obsolete, since most platforms already
+B<will> have a F</usr/bin/perl> or similar provided by the OS.
+
+=item *
+
+Reduce verbosity of C<make install.man>
+
+Previously, two progress messages were emitted for each manpage: one by
+installman itself, and one by the function in install_lib.pl that it calls to
+actually install the file. Disabling the second of those in each case saves
+over 750 lines of unhelpful output.
+
+=item *
+
+Cleanup for C<clang -Weverything> support. [perl 129961]
+
+=item *
+
+Configure: signbit scan was assuming too much, stop assuming negative 0.
+
+=item *
+
+Various compiler warnings have been silenced.
+
+=item *
+
+Several smaller changes have been made to remove impediments to compiling under
+C++11.
+
+=item *
+
+Builds using C<USE_PAD_RESET> now work again; this configuration had
+bit-rotted.
+
+=item *
+
+A probe for C<gai_strerror> was added to F<Configure> that checks if the
+the C<gai_strerror()> routine is available and can be used to
+translate error codes returned by C<getaddrinfo()> into human
+readable strings.
+
+=item *
+
+F<Configure> now aborts if both C<-Duselongdouble> and C<-Dusequadmath> are
+requested.
+L<[perl #126203]|https://rt.perl.org/Public/Bug/Display.html?id=126203>
+
+=item *
+
+Fixed a bug in which F<Configure> could append C<-quadmath> to the archname even
+if it was already present.
+L<[perl #128538]|https://rt.perl.org/Public/Bug/Display.html?id=128538>
+
+=item *
+
+Clang builds with C<-DPERL_GLOBAL_STRUCT> or
+C<-DPERL_GLOBAL_STRUCT_PRIVATE> have
+been fixed (by disabling Thread Safety Analysis for these configurations).
+
+=item *
+
+F<make_ext.pl> no longer updates a module's F<pm_to_blib> file when no
+files require updates. This could cause dependencies, F<perlmain.c>
+in particular, to be rebuilt unnecessarily. [perl #126710]
+
+=item *
+
+The output of C<perl -V> has been reformatted so that each configuration
+and compile-time option is now listed one per line, to improve
+readability.
+
+=item *
+
+C<Configure> now builds C<miniperl> and C<generate_uudmap> if you
+invoke it with C<-Dusecrosscompiler> but not C<-Dtargethost=somehost>.
+This means you can supply your target platform C<config.sh>, generate
+the headers and proceed to build your cross-target perl. [perl #127234]
+
+=item *
+
+Builds with C<-Accflags=-DPERL_TRACE_OPS> now only dump the operator
+counts when the environment variable C<PERL_TRACE_OPS> to be set to a
+non-zero integer. This allows C<make test> to pass on such a build.
+
+=item *
+
+When building with GCC 6 and link-time optimization (the C<-flto> option to
+C<gcc>), C<Configure> was treating all probed symbols as present on the
+system, regardless of whether they actually exist. This has been fixed.
+[perl #128131]
+
+=item *
+
+The F<t/test.pl> library is used for internal testing of Perl itself, and
+also copied by several CPAN modules. Some of those modules must work on
+older versions of Perl, so F<t/test.pl> must in turn avoid newer Perl
+features. Compatibility with Perl 5.8 was inadvertently removed some time
+ago; it has now been restored. [perl #128052]
+
+=item *
+
+The build process no longer emits an extra blank line before building each
+"simple" extension (those with only F<*.pm> and F<*.pod> files).
+
+=back
+
+=head1 Testing
+
+Tests were added and changed to reflect the other additions and changes
+in this release. In addition, these substantive changes were made:
+
+=over 4
+
+=item *
+
+A new test script, F<comp/parser_run.t>, has been added to test
+reads through invalid pointers.
+
+=item *
+
+Tests for locales were erroneously using locales incompatible with Perl.
+
+=item *
+
+Some parts of the test suite that try to exhaustively test edge cases in the
+regex implementation have been restricted to running for a maximum of five
+minutes. On slow systems they could otherwise take several hours, without
+significantly improving our understanding of the correctness of the code
+under test.
+
+In addition, some of those test cases have been split into more files, to
+allow them to be run in parallel on suitable systems.
+
+=item *
+
+A new internal facility allows analysing the time taken by the individual
+tests in Perl's own test suite; see F<Porting/harness-timer-report.pl>.
+
+=item *
+
+F<t/re/regexp_nonull.t> has been added to test that the regular expression
+engine can handle scalars that do not have a null byte just past the end of
+the string.
+
+=item *
+
+A new test script, F<t/op/decl-refs.t>, has been added to test the new feature,
+"Declaring a reference to a variable".
+
+=item *
+
+A new test script, F<t/re/keep_tabs.t> has been added to contain tests
+where C<\t> characters should not be expanded into spaces.
+
+=item *
+
+A new test script, F<t/re/anyof.t>, has been added to test that the ANYOF nodes
+generated by bracketed character classes are as expected.
+
+=item *
+
+There is now more extensive testing of the Unicode-related API macros
+and functions.
+
+=item *
+
+Several of the longer running API test files have been split into
+multiple test files so that they can be run in parallel.
+
+=item *
+
+F<t/harness> now tries really hard not to run tests outside of the Perl
+source tree. [perl #124050]
+
+=back
+
+=head1 Platform Support
+
+=head2 New Platforms
+
+=over 4
+
+=item NetBSD/VAX
+
+Perl now compiles under NetBSD on VAX machines. However, it's not
+possible for that platform to implement floating-point infinities and
+NaNs compatibly with most modern systems, which implement the IEEE-754
+floating point standard. The hexadecimal floating point (C<0x...p[+-]n>
+literals, C<printf %a>) is not implemented, either.
+The C<make test> passes 98% of tests.
+
+=over 4
+
+=item *
+
+Test fixes and minor updates.
+
+=item *
+
+Account for lack of C<inf>, C<nan>, and C<-0.0> support.
+
+=back
+
+=back
+
+=head2 Platform-Specific Notes
+
+=over 4
+
+=item Darwin
+
+don't treat C<-Dprefix=/usr> as special, instead require an extra option
+C<-Ddarwin_distribution> to produce the same results.
+
+=item POSIX
+
+Finish removing POSIX deprecated functions.
+
+=item OS X
+
+OS X El Capitan doesn't implement the C<clock_gettime()> or
+C<clock_getres()> APIs; emulate them as necessary.
+
+=item macOS
+
+Deprecated C<syscall(2)> on macOS 10.12.
+
+=item EBCDIC
+
+Several tests have been updated to work (or be skipped) on EBCDIC platforms.
+
+=item HP-UX
+
+L<Net::Ping> UDP test is skipped on HP-UX.
+
+=item Hurd
+
+The hints for Hurd have been improved enabling malloc wrap and reporting the
+GNU libc used (previously it was an empty string when reported).
+
+=item VAX
+
+VAX floating point formats are now supported on NetBSD.
+
+=item VMS
+
+=over 4
+
+=item *
+
+The path separator for the C<PERL5LIB> and C<PERLLIB> environment entries is
+now a colon (C<":">) when running under a Unix shell. There is no change when
+running under DCL (it's still C<"|">).
+
+=item *
+
+C<configure.com> now recognizes the VSI-branded C compiler and no longer
+recognizes the "DEC"-branded C compiler (as there hasn't been such a thing for
+15 or more years).
+
+=back
+
+=item Windows
+
+=over 4
+
+=item *
+
+Support for compiling perl on Windows using Microsoft Visual Studio 2015
+(containing Visual C++ 14.0) has been added.
+
+This version of VC++ includes a completely rewritten C run-time library, some
+of the changes in which mean that work done to resolve a socket
+C<close()> bug in
+perl #120091 and perl #118059 is not workable in its current state with this
+version of VC++. Therefore, we have effectively reverted that bug fix for
+VS2015 onwards on the basis that being able to build with VS2015 onwards is
+more important than keeping the bug fix. We may revisit this in the future to
+attempt to fix the bug again in a way that is compatible with VS2015.
+
+These changes do not affect compilation with GCC or with Visual Studio versions
+up to and including VS2013, I<i.e.>, the bug fix is retained (unchanged) for those
+compilers.
+
+Note that you may experience compatibility problems if you mix a perl built
+with GCC or VS E<lt>= VS2013 with XS modules built with VS2015, or if you mix a
+perl built with VS2015 with XS modules built with GCC or VS E<lt>= VS2013.
+Some incompatibility may arise because of the bug fix that has been reverted
+for VS2015 builds of perl, but there may well be incompatibility anyway because
+of the rewritten CRT in VS2015 (I<e.g.>, see discussion at
+http://stackoverflow.com/questions/30412951).
+
+=back
+
+=item Win32
+
+=over 4
+
+=item *
+
+Tweaks for Win32 VC vs GCC detection makefile code. This fixes issue that CCHOME
+depends on CCTYPE, which in auto detect mode is set after CCHOME, so CCHOME uses
+the uninit CCTYPE var. Also fix else vs .ELSE in makefile.mk
+
+=item *
+
+fp definitions have been updated.
+
+=back
+
+=item Linux
+
+Drop support for Linux a.out Linux has used ELF for over twenty years.
+
+=item OpenBSD 6
+
+OpenBSD 6 still does not support returning pid, gid or uid with SA_SIGINFO.
+Make sure this is accounted for.
+
+=item FreeBSD
+
+F<t/uni/overload.t>: Skip hanging test on FreeBSD.
+
+=back
+
+=head1 Internal Changes
+
+=over 4
+
+=item *
+
+A new API function C<sv_setvpv_bufsize()> allows simultaneously setting the
+length and allocated size of the buffer in an C<SV>, growing the buffer if
+necessary.
+
+=item *
+
+A new API macro C<SvPVCLEAR()> sets its C<SV> argument to an empty string,
+like Perl-space C<$x = ''>, but with several optimisations.
+
+=item *
+
+Several new macros and functions for dealing with Unicode and
+UTF-8-encoded strings have been added to the API, as well as some
+changes in
+functionality of existing functions (see L<perlapi/Unicode Support> for
+more details):
+
+=over
+
+=item *
+
+New versions of macros like C<isALPHA_utf8> and C<toLOWER_utf8> have
+been added, each with the
+suffix C<_safe>, like C<isSPACE_utf8_safe>. These take an extra
+parameter, giving an upper limit of how far into the string it is safe
+to read. Using the old versions could cause attempts to read beyond the
+end of the input buffer if the UTF-8 is not well-formed, and their use
+now raises a deprecation warning. Details are at
+L<perlapi/Character classification>.
+
+=item *
+
+Calling macros like C<isALPHA_utf8> on malformed UTF-8 have issued a
+deprecation warning since Perl 5.18. They now die.
+Similarly, macros like C<toLOWER_utf8> on malformed UTF-8 now die.
+
+=item *
+
+Several new macros for analysing the validity of utf8 sequences. These
+are:
+
+L<C<UTF8_GOT_ABOVE_31_BIT>|perlapi/UTF8_GOT_ABOVE_31_BIT>
+L<C<UTF8_GOT_CONTINUATION>|perlapi/UTF8_GOT_CONTINUATION>
+L<C<UTF8_GOT_EMPTY>|perlapi/UTF8_GOT_EMPTY>
+L<C<UTF8_GOT_LONG>|perlapi/UTF8_GOT_LONG>
+L<C<UTF8_GOT_NONCHAR>|perlapi/UTF8_GOT_NONCHAR>
+L<C<UTF8_GOT_NON_CONTINUATION>|perlapi/UTF8_GOT_NON_CONTINUATION>
+L<C<UTF8_GOT_OVERFLOW>|perlapi/UTF8_GOT_OVERFLOW>
+L<C<UTF8_GOT_SHORT>|perlapi/UTF8_GOT_SHORT>
+L<C<UTF8_GOT_SUPER>|perlapi/UTF8_GOT_SUPER>
+L<C<UTF8_GOT_SURROGATE>|perlapi/UTF8_GOT_SURROGATE>
+L<C<UTF8_IS_INVARIANT>|perlapi/UTF8_IS_INVARIANT>
+L<C<UTF8_IS_NONCHAR>|perlapi/UTF8_IS_NONCHAR>
+L<C<UTF8_IS_SUPER>|perlapi/UTF8_IS_SUPER>
+L<C<UTF8_IS_SURROGATE>|perlapi/UTF8_IS_SURROGATE>
+L<C<UVCHR_IS_INVARIANT>|perlapi/UVCHR_IS_INVARIANT>
+L<C<isUTF8_CHAR_flags>|perlapi/isUTF8_CHAR_flags>
+L<C<isSTRICT_UTF8_CHAR>|perlapi/isSTRICT_UTF8_CHAR>
+L<C<isC9_STRICT_UTF8_CHAR>|perlapi/isC9_STRICT_UTF8_CHAR>
+
+=item *
+
+Functions that are all extensions of the C<is_utf8_string_I<*>()> functions,
+that apply various restrictions to the UTF-8 recognized as valid:
+
+L<C<is_strict_utf8_string>|perlapi/is_strict_utf8_string>,
+L<C<is_strict_utf8_string_loc>|perlapi/is_strict_utf8_string_loc>,
+L<C<is_strict_utf8_string_loclen>|perlapi/is_strict_utf8_string_loclen>,
+
+L<C<is_c9strict_utf8_string>|perlapi/is_c9strict_utf8_string>,
+L<C<is_c9strict_utf8_string_loc>|perlapi/is_c9strict_utf8_string_loc>,
+L<C<is_c9strict_utf8_string_loclen>|perlapi/is_c9strict_utf8_string_loclen>,
+
+L<C<is_utf8_string_flags>|perlapi/is_utf8_string_flags>,
+L<C<is_utf8_string_loc_flags>|perlapi/is_utf8_string_loc_flags>,
+L<C<is_utf8_string_loclen_flags>|perlapi/is_utf8_string_loclen_flags>,
+
+L<C<is_utf8_fixed_width_buf_flags>|perlapi/is_utf8_fixed_width_buf_flags>,
+L<C<is_utf8_fixed_width_buf_loc_flags>|perlapi/is_utf8_fixed_width_buf_loc_flags>,
+L<C<is_utf8_fixed_width_buf_loclen_flags>|perlapi/is_utf8_fixed_width_buf_loclen_flags>.
+
+L<C<is_utf8_invariant_string>|perlapi/is_utf8_invariant_string>.
+L<C<is_utf8_valid_partial_char>|perlapi/is_utf8_valid_partial_char>.
+L<C<is_utf8_valid_partial_char_flags>|perlapi/is_utf8_valid_partial_char_flags>.
+
+=item *
+
+The functions L<C<utf8n_to_uvchr>|perlapi/utf8n_to_uvchr> and its
+derivatives have had several changes of behaviour.
+
+Calling them, while passing a string length of 0 is now asserted against
+in DEBUGGING builds, and otherwise returns the Unicode REPLACEMENT
+CHARACTER. If you have nothing to decode, you shouldn't call the decode
+function.
+
+They now return the Unicode REPLACEMENT CHARACTER if called with UTF-8
+that has the overlong malformation, and that malformation is allowed by
+the input parameters. This malformation is where the UTF-8 looks valid
+syntactically, but there is a shorter sequence that yields the same code
+point. This has been forbidden since Unicode version 3.1.
+
+They now accept an input
+flag to allow the overflow malformation. This malformation is when the
+UTF-8 may be syntactically valid, but the code point it represents is
+not capable of being represented in the word length on the platform.
+What "allowed" means in this case is that the function doesn't return an
+error, and it advances the parse pointer to beyond the UTF-8 in
+question, but it returns the Unicode REPLACEMENT CHARACTER as the value
+of the code point (since the real value is not representable).
+
+C<utf8n_to_uvchr> has been changed to not
+abandon searching for other malformations when the first one is
+encountered. A call to it thus can generate multiple diagnostics,
+instead of just one.
+
+=item *
+
+C<valid_utf8_to_uvchr()> has been added to the API (although it was
+present in core earlier). Like C<utf8_to_uvchr_buf()>, but assumes that
+the next character is well-formed. Use with caution.
+
+=item *
+
+A new function, L<C<utf8n_to_uvchr_error>|perlapi/utf8n_to_uvchr_error>,
+has been added for
+use by modules that need to know the details of UTF-8 malformations
+beyond pass/fail. Previously, the only ways to know why a sequence was
+ill-formed was to capture and parse the generated diagnostics, or to do
+your own analysis.
+
+=item *
+
+There is now a safer version of utf8_hop(), called utf8_hop_safe().
+Unlike utf8_hop(), utf8_hop_safe() won't navigate before the beginning or
+after the end of the supplied buffer.
+
+=item *
+
+Two new functions, C<utf8_hop_forward()> and C<utf8_hop_back()> are
+similar to C<utf8_hop_safe()> but are for when you know which direction
+you wish to travel.
+
+=item *
+
+Two new macros which return useful utf8 byte sequences:
+
+L<C<BOM_UTF8>|perlapi/BOM_UTF8>
+L<C<REPLACEMENT_CHARACTER_UTF8>|perlapi/REPLACEMENT_CHARACTER_UTF8>
+
+=back
+
+=item *
+
+Perl is now built with the C<PERL_OP_PARENT> compiler define enabled by
+default. To disable it, use the C<PERL_NO_OP_PARENT> compiler define.
+This flag alters how the C<op_sibling> field is used in C<OP> structures,
+and has been available optionally since perl 5.22.
+
+See L<perl5220delta/"Internal Changes"> for more details of what this
+build option does.
+
+=item *
+
+Three new ops, C<OP_ARGELEM>, C<OP_ARGDEFELEM> and C<OP_ARGCHECK> have
+been added. These are intended principally to implement the individual
+elements of a subroutine signature, plus any overall checking required.
+
+=item *
+
+The C<op_class()> API function has been added. This is like the existing
+C<OP_CLASS()> macro, but can more accurately determine what struct an op
+has been allocated as. For example C<OP_CLASS()> might return
+C<OA_BASEOP_OR_UNOP> indicating that ops of this type are usually
+allocated as an C<OP> or C<UNOP>; while C<op_class()> will return
+C<OPclass_BASEOP> or C<OPclass_UNOP> as appropriate.
+
+=item *
+
+All parts of the internals now agree that the C<sassign> op is a C<BINOP>;
+previously it was listed as a C<BASEOP> in F<regen/opcodes>, which meant
+that several parts of the internals had to be special-cased to accommodate
+it. This oddity's original motivation was to handle code like C<$x ||= 1>;
+that is now handled in a simpler way.
+
+=item *
+
+The output format of the C<op_dump()> function (as used by C<perl -Dx>)
+has changed: it now displays an "ASCII-art" tree structure, and shows more
+low-level details about each op, such as its address and class.
+
+=item *
+
+The C<PADOFFSET> type has changed from being unsigned to signed, and
+several pad-related variables such as C<PL_padix> have changed from being
+of type C<I32> to type C<PADOFFSET>.
+
+=item *
+
+The C<DEBUGGING>-mode output for regex compilation and execution has been
+enhanced.
+
+=item *
+
+Several obscure SV flags have been eliminated, sometimes along with the
+macros which manipulate them: C<SVpbm_VALID>, C<SVpbm_TAIL>, C<SvTAIL_on>,
+C<SvTAIL_off>, C<SVrepl_EVAL>, C<SvEVALED>
+
+=item *
+
+An OP op_private flag has been eliminated: C<OPpRUNTIME>. This used to
+often get set on C<PMOP>s, but had become meaningless over time.
+
+=back
+
+=head1 Selected Bug Fixes
+
+=over 4
+
+=item *
+
+Perl no longer panics when switching into some locales on machines with
+buggy C<strxfrm()> implementations in their libc. [perl #121734]
+
+=item *
+
+C< $-{$name} > would leak an C<AV> on each access if the regular
+expression had no named captures. The same applies to access to any
+hash tied with L<Tie::Hash::NamedCapture> and C<< all =E<gt> 1 >>. [perl
+#130822]
+
+=item *
+
+Attempting to use the deprecated variable C<$#> as the object in an
+indirect object method call could cause a heap use after free or
+buffer overflow. [perl #129274]
+
+=item *
+
+When checking for an indirect object method call in some rare cases
+the parser could reallocate the line buffer but then continue to use
+pointers to the old buffer. [perl #129190]
+
+=item *
+
+Supplying a glob as the format argument to
+L<C<formline>|perlfunc/formline> would
+cause an assertion failure. [perl #130722]
+
+=item *
+
+Code like C< $value1 =~ qr/.../ ~~ $value2 > would have the match
+converted into a C<qr//> operator, leaving extra elements on the stack to
+confuse any surrounding expression. [perl #130705]
+
+=item *
+
+Since v5.24 in some obscure cases, a regex which included code blocks
+from multiple sources (I<e.g.>, via embedded via C<qr//> objects) could end up
+with the wrong current pad and crash or give weird results. [perl #129881]
+
+=item *
+
+Occasionally C<local()>s in a code block within a patterns weren't being
+undone when the pattern matching backtracked over the code block.
+[perl #126697]
+
+=item *
+
+Using C<substr()> to modify a magic variable could access freed memory
+in some cases. [perl #129340]
+
+=item *
-=over 4
+Under C<use utf8>, the entire Perl program is now checked that the UTF-8
+is wellformed. [perl #126310].
=item *
-L<B> has been upgraded from version 1.65 to 1.68.
+The range operator C<".."> on strings now handles its arguments correctly when in
+the scope of the L<< C<unicode_strings>|feature/"The 'unicode_strings' feature" >>
+feature. The previous behaviour was sufficiently unexpected that we believe no
+correct program could have made use of it.
=item *
-L<CPAN> has been upgraded from version 2.16 to 2.17.
+The C<split> operator did not ensure enough space was allocated for
+its return value in scalar context. It could then write a single
+pointer immediately beyond the end of the memory block allocated for
+the stack. [perl #130262]
=item *
-L<feature> has been upgraded from version 1.46 to 1.47.
+Using a large code point with the C<"W"> pack template character with
+the current output position aligned at just the right point could
+cause a write a single zero byte immediately beyond the end of an
+allocated buffer. [perl #129149]
=item *
-L<Getopt::Std> has been upgraded from version 1.11 to 1.12.
+Supplying the form picture argument as part of the form argument list
+where the picture specifies modifying the argument could cause an
+access to the new freed compiled form. [perl #129125]
=item *
-L<Module::CoreList> has been upgraded from version 5.20170120 to 5.20170220.
+Fix a problem with sort's build-in compare, where it would not sort
+correctly with 64-bit integers, and non-long doubles. [perl #130335]
=item *
-L<open> has been upgraded from version 1.10 to 1.11.
+Fix issues with C</(?{ ... E<lt>E<lt>EOF })/> that broke Method-Signatures. [perl #130398]
=item *
-L<PerlIO> has been upgraded from version 1.09 to 1.10.
+Fix a macro which caused syntax error on an EBCDIC build.
=item *
-L<Storable> has been upgraded from version 2.61 to 2.62.
+Prevent tests from getting hung up on 'NonStop' option. [perl #130445]
=item *
-L<Thread::Queue> has been upgraded from version 3.11 to 3.12.
+Fixed an assertion failure with C<chop> and C<chomp>, which
+could be triggered by C<chop(@x =~ tr/1/1/)>. [perl #130198].
=item *
-L<threads> has been upgraded from version 2.12 to 2.13.
+Fixed a comment skipping error in patterns under C</x>; it could stop
+skipping a byte early, which could be in the middle of a UTF-8
+character. [perl #130495].
-=back
+=item *
-=head1 Diagnostics
+F<perldb> now ignores F</dev/tty> on non-Unix systems. [perl #113960];
-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>.
+=item *
-=head2 Changes to Existing Diagnostics
+Fix assertion failure for C<{}-E<gt>$x> when C<$x> isn't defined. [perl #130496].
-=over 4
+=item *
+
+DragonFly BSD now has support for C<setproctitle()>. [perl #130068].
=item *
-Use of unassigned code point or non-standalone grapheme for a delimiter will be a fatal error starting in Perl 5.30
+Fix an assertion error which could be triggered when a lookahead string
+in patterns exceeded a minimum length. [perl #130522].
-This was changed to drop a leading C<v> in C<v5.30>, so it uses the same
-style as other deprecation messages.
+=item *
-=item *
+Only warn once per literal about a misplaced C<"_">. [perl #70878].
-"\c%c" is more clearly written simply as "%s".
+=item *
-It was decided to undeprecate the use of "\c%c", see L<http://www.nntp.perl.org/group/perl.perl5.porters/2017/02/msg242944.html>
+Ensure range-start is set after error in C<tr///>. [perl #129342].
-=back
+=item *
-=head1 Platform Support
+Don't read past start of string for unmatched backref; otherwise,
+we may have heap buffer overflow. [perl #129377].
-=head2 Platform-Specific Notes
+=item *
-=over 4
+C<use re 'strict'> is supposed to warn if you use a range whose start
+and end digit aren't from the same group of 10. It didn't do that
+for five groups of mathematical digits starting at U+1D7E.
-=item Windows
+=item *
-=over 4
+A sub containing a "forward" declaration with the same name (I<e.g.>,
+C<sub c { sub c; }>) could sometimes crash or loop infinitely. [perl
+#129090]
=item *
-Support for compiling perl on Windows using Microsoft Visual Studio 2015
-(containing Visual C++ 14.0) has been added.
+A crash in executing a regex with a non-anchored UTF-8 substring against a
+target string that also used UTF-8 has been fixed. [perl #129350]
-This version of VC++ includes a completely rewritten C run-time library, some
-of the changes in which mean that work done to resolve a socket close() bug in
-perl #120091 and perl #118059 is not workable in its current state with this
-version of VC++. Therefore, we have effectively reverted that bug fix for
-VS2015 onwards on the basis that being able to build with VS2015 onwards is
-more important than keeping the bug fix. We may revisit this in the future to
-attempt to fix the bug again in a way that is compatible with VS2015.
+=item *
-These changes do not affect compilation with GCC or with Visual Studio versions
-up to and including VS2013, i.e. the bug fix is retained (unchanged) for those
-compilers.
+Previously, a shebang line like C<#!perl -i u> could be erroneously
+interpreted as requesting the C<-u> option. This has been fixed. [perl
+#129336]
-Note that you may experience compatibility problems if you mix a perl built
-with GCC or VS E<lt>= VS2013 with XS modules built with VS2015, or if you mix a
-perl built with VS2015 with XS modules built with GCC or VS E<lt>= VS2013.
-Some incompatibility may arise because of the bug fix that has been reverted
-for VS2015 builds of perl, but there may well be incompatibility anyway because
-of the rewritten CRT in VS2015 (e.g. see discussion at
-http://stackoverflow.com/questions/30412951).
+=item *
-=back
+The regex engine was previously producing incorrect results in some rare
+situations when backtracking past a trie that matches only one thing; this
+showed up as capture buffers (C<$1>, C<$2>, I<etc.>) erroneously containing data
+from regex execution paths that weren't actually executed for the final
+match. [perl #129897]
-=back
+=item *
-=head1 Internal Changes
+Certain regexes making use of the experimental C<regex_sets> feature could
+trigger an assertion failure. This has been fixed. [perl #129322]
-=over 4
+=item *
+
+Invalid assignments to a reference constructor (I<e.g.>, C<\eval=time>) could
+sometimes crash in addition to giving a syntax error. [perl #125679]
=item *
-The C<op_class()> API function has been added. This is like the existing
-C<OP_CLASS()> macro, but can more accurately determine what struct an op
-has been allocated as. For example C<OP_CLASS()> might return
-C<OA_BASEOP_OR_UNOP> indicating that ops of this type are usually
-allocated as an C<OP> or C<UNOP>; while C<op_class()> will return
-C<OPclass_BASEOP> or C<OPclass_UNOP> as appropriate.
+The parser could sometimes crash if a bareword came after C<evalbytes>.
+[perl #129196]
=item *
-The output format of the C<op_dump()> function (as used by C<perl -Dx>)
-has changed: it now displays an "ASCII-art" tree structure, and shows more
-low-level details about each op, such as its address and class.
+Autoloading via a method call would warn erroneously ("Use of inherited
+AUTOLOAD for non-method") if there was a stub present in the package into
+which the invocant had been blessed. The warning is no longer emitted in
+such circumstances. [perl #47047]
-=back
+=item *
-=head1 Selected Bug Fixes
+The use of C<splice> on arrays with nonexistent elements could cause other
+operators to crash. [perl #129164]
-=over 4
+=item *
+
+Fixed case where C<re_untuit_start> will overshoot the length of a utf8
+string. [perl #129012]
=item *
-Attempting to use the deprecated variable C<$#> as the object in an
-indirect object method call could cause a heap use after free or
-buffer overflow. [perl #129274]
+Handle C<CXt_SUBST> better in C<Perl_deb_stack_all>, previously it wasn't
+checking that the I<current> C<cx> is the right type, and instead was always
+checking the base C<cx> (effectively a noop). [perl #129029]
=item *
-When checking for an indirect object method call in some rare cases
-the parser could reallocate the line buffer but then continue to use
-pointers to the old buffer. [perl #129190]
+Fixed two possible use-after-free bugs in C<Perl_yylex>. C<Perl_yylex>
+maintains up to two pointers into the parser buffer, one of which can
+become stale under the right conditions. [perl #129069]
=item *
-Supplying a glob as the format argument to L<perlfunc/formline> would
-cause an assertion failure. [perl #130722]
+Fixed a crash with C<s///l> where it thought it was dealing with UTF-8
+when it wasn't. [perl #129038]
=item *
-Code like C< $value1 =~ qr/.../ ~~ $value2 > would have the match
-converted into a qr// operator, leaving extra elements on the stack to
-confuse any surrounding expression. [perl #130705]
+Fixed place where regex was not setting the syntax error correctly.
+[perl #129122]
=item *
-Since 5.24.0 in some obscure cases, a regex which included code blocks
-from multiple sources (e.g. via embedded via qr// objects) could end up
-with the wrong current pad and crash or give weird results. [perl #129881]
+The C<&.> operator (and the C<"&"> operator, when it treats its arguments as
+strings) were failing to append a trailing null byte if at least one string
+was marked as utf8 internally. Many code paths (system calls, regexp
+compilation) still expect there to be a null byte in the string buffer
+just past the end of the logical string. An assertion failure was the
+result. [perl #129287]
=item *
-Occasionally C<local()>s in a code block within a patterns weren't being
-undone when the pattern matching backtracked over the code block.
-[perl #126697]
+Check C<pack_sockaddr_un()>'s return value because C<pack_sockaddr_un()>
+silently truncates the supplied path if it won't fit into the C<sun_path>
+member of C<sockaddr_un>. This may change in the future, but for now
+check the path in theC<sockaddr> matches the desired path, and skip if
+it doesn't. [perl #128095]
=item *
-Using C<substr()> to modify a magic variable could access freed memory
-in some cases. [perl #129340]
+Make sure C<PL_oldoldbufptr> is preserved in C<scan_heredoc()>. In some
+cases this is used in building error messages. [perl #128988]
+
+=item *
+
+Check for null PL_curcop in IN_LC() [perl #129106]
+
+=item *
+
+Fixed the parser error handling for an 'C<:attr(foo>' that does not have
+an ending 'C<")">'.
+
+=item *
+
+Fix C<Perl_delimcpy()> to handle a backslash as last char, this
+actually fixed two bugs, [perl #129064] and [perl #129176].
+
+=item *
+
+[perl #129267] rework C<gv_fetchmethod_pvn_flags> separator parsing to
+prevent possible string overrun with invalid len in F<gv.c>
+
+=item *
+
+Problems with in-place array sorts: code like C<@a = sort { ... } @a>,
+where the source and destination of the sort are the same plain array, are
+optimised to do less copying around. Two side-effects of this optimisation
+were that the contents of C<@a> as visible to to sort routine were
+partially sorted, and under some circumstances accessing C<@a> during the
+sort could crash the interpreter. Both these issues have been fixed, and
+Sort functions see the original value of C<@a>.
+
+=item *
+
+Non-ASCII string delimiters are now reported correctly in error messages
+for unterminated strings. [perl #128701]
+
+=item *
+
+C<pack("p", ...)> used to emit its warning ("Attempt to pack pointer to
+temporary value") erroneously in some cases, but has been fixed.
+
+=item *
+
+C<@DB::args> is now exempt from "used once" warnings. The warnings only
+occurred under B<-w>, because F<warnings.pm> itself uses C<@DB::args>
+multiple times.
+
+=item *
+
+The use of built-in arrays or hash slices in a double-quoted string no
+longer issues a warning ("Possible unintended interpolation...") if the
+variable has not been mentioned before. This affected code like
+C<qq|@DB::args|> and C<qq|@SIG{'CHLD', 'HUP'}|>. (The special variables
+C<@-> and C<@+> were already exempt from the warning.)
+
+=item *
+
+C<gethostent> and similar functions now perform a null check internally, to
+avoid crashing with torsocks. This was a regression from v5.22. [perl
+#128740]
+
+=item *
+
+C<defined *{'!'}>, C<defined *{'['}>, and C<defined *{'-'}> no longer leak
+memory if the typeglob in question has never been accessed before.
+
+=item *
+
+Mentioning the same constant twice in a row (which is a syntax error) no
+longer fails an assertion under debugging builds. This was a regression
+from v5.20. [perl #126482]
+
+=item *
+
+Many issues relating to C<printf "%a"> of hexadecimal floating point
+were fixed. In addition, the "subnormals" (formerly known as "denormals")
+floating point numbers are now supported both with the plain IEEE 754
+floating point numbers (64-bit or 128-bit) and the x86 80-bit
+"extended precision". Note that subnormal hexadecimal floating
+point literals will give a warning about "exponent underflow".
+[perl #128843, #128889, #128890, #128893, #128909, #128919]
+
+=item *
+
+A regression in v5.24 with C<tr/\N{U+...}/foo/> when the code point was between
+128 and 255 has been fixed. [perl #128734].
+
+=item *
+
+Use of a string delimiter whose code point is above 2**31 now works
+correctly on platforms that allow this. Previously, certain characters,
+due to truncation, would be confused with other delimiter characters
+with special meaning (such as C<"?"> in C<m?...?>), resulting
+in inconsistent behaviour. Note that this is non-portable,
+and is based on Perl's extension to UTF-8, and is probably not
+displayable nor enterable by any editor. [perl #128738]
+
+=item *
+
+C<@{x> followed by a newline where C<"x"> represents a control or non-ASCII
+character no longer produces a garbled syntax error message or a crash.
+[perl #128951]
+
+=item *
+
+An assertion failure with C<%: = 0> has been fixed.
+L<[perl #128238]|https://rt.perl.org/Public/Bug/Display.html?id=128238>
+
+=item *
+
+In Perl 5.18, the parsing of C<"$foo::$bar"> was accidentally changed, such
+that it would be treated as C<$foo."::".$bar>. The previous behavior, which
+was to parse it as C<$foo:: . $bar>, has been restored.
+L<[perl #128478]|https://rt.perl.org/Public/Bug/Display.html?id=128478>
+
+=item *
+
+Since Perl 5.20, line numbers have been off by one when perl is invoked with
+the B<-x> switch. This has been fixed.
+L<[perl #128508]|https://rt.perl.org/Public/Bug/Display.html?id=128508>
+
+=item *
+
+Vivifying a subroutine stub in a deleted stash (I<e.g.>, C<delete $My::{"Foo::"};
+\&My::Foo::foo>) no longer crashes. It had begun crashing in Perl 5.18.
+L<[perl #128532]|https://rt.perl.org/Public/Bug/Display.html?id=128532>
+
+=item *
+
+Some obscure cases of subroutines and file handles being freed at the same time
+could result in crashes, but have been fixed. The crash was introduced in Perl
+5.22.
+L<[perl #128597]|https://rt.perl.org/Public/Bug/Display.html?id=128597>
+
+=item *
+
+Code that looks for a variable name associated with an uninitialized value
+could cause an assertion failure in cases where magic is involved, such as
+C<$ISA[0][0]>. This has now been fixed.
+L<[perl #128253]|https://rt.perl.org/Public/Bug/Display.html?id=128253>
+
+=item *
+
+A crash caused by code generating the warning "Subroutine STASH::NAME
+redefined" in cases such as C<sub P::f{} undef *P::; *P::f =sub{};> has been
+fixed. In these cases, where the STASH is missing, the warning will now appear
+as "Subroutine NAME redefined".
+L<[perl #128257]|https://rt.perl.org/Public/Bug/Display.html?id=128257>
+
+=item *
+
+Fixed an assertion triggered by some code that handles deprecated behavior in
+formats, I<e.g.>, in cases like this:
+
+ format STDOUT =
+ @
+ 0"$x"
+
+L<[perl #128255]|https://rt.perl.org/Public/Bug/Display.html?id=128255>
+
+=item *
+
+A possible divide by zero in string transformation code on Windows has been
+avoided, fixing a crash when collating an empty string.
+L<[perl #128618]|https://rt.perl.org/Public/Bug/Display.html?id=128618>
+
+=item *
+
+Some regular expression parsing glitches could lead to assertion failures with
+regular expressions such as C</(?E<lt>=/> and C</(?E<lt>!/>. This has now been fixed.
+L<[perl #128170]|https://rt.perl.org/Public/Bug/Display.html?id=128170>
+
+=item *
+
+C< until ($x = 1) { ... } > and C< ... until $x = 1 > now properly
+warn when syntax warnings are enabled. [perl #127333]
+
+=item *
+
+socket() now leaves the error code returned by the system in C<$!> on
+failure. [perl #128316]
+
+=item *
+
+Assignment variants of any bitwise ops under the C<bitwise> feature would
+crash if the left-hand side was an array or hash. [perl #128204]
+
+=item *
+
+C<require> followed by a single colon (as in C<foo() ? require : ...> is
+now parsed correctly as C<require> with implicit C<$_>, rather than
+C<require "">. [perl #128307]
+
+=item *
+
+Scalar C<keys %hash> can now be assigned to consistently in all scalar
+lvalue contexts. Previously it worked for some contexts but not others.
+
+=item *
+
+List assignment to C<vec> or C<substr> with an array or hash for its first
+argument used to result in crashes or "Can't coerce" error messages at run
+time, unlike scalar assignment, which would give an error at compile time.
+List assignment now gives a compile-time error, too. [perl #128260]
+
+=item *
+
+Expressions containing an C<&&> or C<||> operator (or their synonyms C<and>
+and C<or>) were being compiled incorrectly in some cases. If the left-hand
+side consisted of either a negated bareword constant or a negated C<do {}>
+block containing a constant expression, and the right-hand side consisted of
+a negated non-foldable expression, one of the negations was effectively
+ignored. The same was true of C<if> and C<unless> statement modifiers,
+though with the left-hand and right-hand sides swapped. This long-standing
+bug has now been fixed. [perl #127952]
+
+=item *
+
+C<reset> with an argument no longer crashes when encountering stash entries
+other than globs. [perl #128106]
+
+=item *
+
+Assignment of hashes to, and deletion of, typeglobs named C<*::::::> no
+longer causes crashes. [perl #128086]
+
+=item *
+
+Handle C<SvIMMORTALs> in LHS of list assign. [perl #129991]
+
+=item *
+
+Assertion failure with user-defined Unicode-like properties. [perl #130010]
+
+=item *
+
+Fix error message for unclosed C<\N{> in regcomp.
+
+An unclosed C<\N{> could give the wrong error message
+C<"\N{NAME} must be resolved by the lexer">.
+
+=item *
+
+List assignment in list context where the LHS contained aggregates and
+where there were not enough RHS elements, used to skip scalar lvalues.
+Previously, C<(($a,$b,@c,$d) = (1))> in list context returned C<($a)>; now
+it returns C<($a,$b,$d)>. C<(($a,$b,$c) = (1))> is unchanged: it still
+returns C<($a,$b,$c)>. This can be seen in the following:
+
+ sub inc { $_++ for @_ }
+ inc(($a,$b,@c,$d) = (10))
+
+Formerly, the values of C<($a,$b,$d)> would be left as C<(11,undef,undef)>;
+now they are C<(11,1,1)>.
+
+=item *
+
+Code like this: C</(?{ s!!! })/> can trigger infinite recursion on the C
+stack (not the normal perl stack) when the last successful pattern in
+scope is itself. We avoid the segfault by simply forbidding the use of
+the empty pattern when it would resolve to the currently executing
+pattern. [perl 129903]
+
+=item *
+
+Avoid reading beyond the end of the line buffer when there's a
+short UTF-8 character at the end. [perl 128997]
+
+=item *
+
+Fix firstchar bitmap under utf8 with prefix optimisation. [perl 129950]
+
+=item *
+
+Make F<Carp/t/arg_string.t>: be liberal in C<f>/C<p> formats. [perl 129954]
+
+=item *
+
+Make C<do "a\0b"> fail silently instead of throwing an error. [perl 129928]
+
+=item *
+
+Make C<chdir> allocate the stack it needs. [perl 129130]
+
+=back
+
+=head1 Known Problems
+
+=over 4
+
+=item *
+
+Some modules have been broken by the L<context stack rework|/Internal Changes>.
+These modules were relying on non-guaranteed implementation details in
+the perl interpreter.
+Their maintainers have been informed, and should contact perl5-porters for
+advice if needed. Below is a subset of these modules:
+
+=over 4
+
+=item * L<Algorithm::Permute>
+
+=item * L<Coro>
+
+L<Coro> and Perl 5.22 were already incompatible due to a change in the perl
+interpreter,
+and the reworking on the perl context stack creates a further incompatibility.
+perl5-porters has L<discussed the issue on the mailing
+list|http://www.nntp.perl.org/group/perl.perl5.porters/2016/05/msg236174.html>.
+
+=item * L<Data::Alias>
+
+=item * L<RPerl>
+
+=item * L<Scope::Upper>
+
+=item * L<TryCatch>
+
+=back
+
+=item *
+
+The module L<lexical::underscore> no longer works on Perl 5.24, because perl
+no longer has a lexical C<$_>!
=item *
-Perl 5.25.9 was fixed so that under C<use utf8>, the entire Perl program
-is checked that the UTF-8 is wellformed. It turns out that several edge
-cases were missed, and are now fixed. [perl #126310] was the original
-ticket.
+C<mod_perl> has been patched for compatibility for v5.22 and later but no
+release has been made. The relevant patch (and other changes) can be found in
+their source code repository, L<mirrored at
+GitHub|https://github.com/apache/mod_perl/commit/82827132efd3c2e25cc413c85af61bb63375da6e>.
=back
+=head1 Errata From Previous Releases
+
+=over 4
+
+=item *
+
+Parsing bad POSIX charclasses no longer leaks memory.
+L<[perl #128313]|https://rt.perl.org/Public/Bug/Display.html?id=128313>
+
+=item *
+
+Fixed issues with recursive regexes. The behavior was fixed in Perl 5.24.
+L<[perl #126182]|https://rt.perl.org/Public/Bug/Display.html?id=126182>
+
+=back
+
+=head1 Obituary
+
+Jon Portnoy (AVENJ), a prolific Perl author and admired Gentoo community
+member, has passed away on August 10, 2016. He will be remembered and
+missed by all those who he came in contact with, and enriched with his
+intellect, wit, and spirit.
+
+It is with great sadness that we also note Kip Hampton's passing. Probably
+best known as the author of the Perl & XML column on XML.com, he was a
+core contributor to AxKit, an XML server platform that became an Apache
+Foundation project. He was a frequent speaker in the early days at
+OSCON, and most recently at YAPC::NA in Madison. He was frequently on
+irc.perl.org as `ubu`, generally in the #axkit-dahut community, the
+group responsible for YAPC::NA Asheville in 2011.
+
+Kip and his constant contributions to the community will be greatly
+missed.
+
=head1 Acknowledgements
-Perl 5.25.10 represents approximately 4 weeks of development since Perl 5.25.9
-and contains approximately 12,000 lines of changes across 200 files from 25
+Perl 5.26.0 represents approximately 12 months of development since Perl 5.24.0
+and contains approximately 370,000 lines of changes across 2,600 files from 86
authors.
Excluding auto-generated files, documentation and release tools, there were
-approximately 6,700 lines of changes to 130 .pm, .t, .c and .h files.
+approximately 230,000 lines of changes to 1,800 .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 5.25.10:
-
-Aaron Crane, Abigail, Andreas König, Andy Lester, Chris 'BinGOs' Williams,
-Christian Millour, Colin Newell, Dagfinn Ilmari Mannsåker, David Mitchell,
-Hugo van der Sanden, James E Keenan, Jarkko Hietaniemi, Jerry D. Hedden, John
-Lightsey, Karl Williamson, Neil Bowers, Pali, Renee Baecker, Sawyer X, Sergey
-Aleynikov, Steffen Müller, Steve Hay, Tony Cook, Yves Orton, Zefram.
+of users and developers. The following people are known to have contributed the
+improvements that became Perl 5.26.0:
+
+Aaron Crane, Abigail, Ævar Arnfjörð Bjarmason, Alex Vandiver, Andreas
+König, Andreas Voegele, Andrew Fresh, Andy Lester, Aristotle Pagaltzis, Chad
+Granum, Chase Whitener, Chris 'BinGOs' Williams, Chris Lamb, Christian Hansen,
+Christian Millour, Colin Newell, Craig A. Berry, Dagfinn Ilmari Mannsåker, Dan
+Collins, Daniel Dragan, Dave Cross, Dave Rolsky, David Golden, David H.
+Gutteridge, David Mitchell, Dominic Hargreaves, Doug Bell, E. Choroba, Ed Avis,
+Father Chrysostomos, François Perrad, Hauke D, H.Merijn Brand, Hugo van der
+Sanden, Ivan Pozdeev, James E Keenan, James Raspass, Jarkko Hietaniemi, Jerry
+D. Hedden, Jim Cromie, J. Nick Koston, John Lightsey, Karen Etheridge, Karl
+Williamson, Leon Timmermans, Lukas Mai, Matthew Horsfall, Maxwell Carey, Misty
+De Meo, Neil Bowers, Nicholas Clark, Nicolas R., Niko Tyni, Pali, Paul
+Marquess, Peter Avalos, Petr Písař, Pino Toscano, Rafael Garcia-Suarez, Reini
+Urban, Renee Baecker, Ricardo Signes, Richard Levitte, Rick Delaney, Salvador
+Fandiño, Samuel Thibault, Sawyer X, Sébastien Aperghis-Tramoni, Sergey
+Aleynikov, Shlomi Fish, Smylers, Stefan Seifert, Steffen Müller, Stevan
+Little, Steve Hay, Steven Humphrey, Sullivan Beck, Theo Buehler, Thomas Sibley,
+Todd Rinaldo, Tomasz Konojacki, Tony Cook, Unicode Consortium, Yaroslav Kuzmin,
+Yves Orton, Zefram.
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
+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
+included in Perl's core. We're grateful to the entire CPAN community for
helping Perl to flourish.
For a more complete list of all of Perl's historical contributors, please see
=head1 Reporting Bugs
-If you find what you think is a bug, you might check the perl bug database
-at L<https://rt.perl.org/> . There may also be information at
+If you find what you think is a bug, you might check the articles recently
+posted to the comp.lang.perl.misc newsgroup and the perl bug database at
+L<https://rt.perl.org/> . There may also be information at
L<http://www.perl.org/> , the Perl Home Page.
If you believe you have an unreported bug, please run the L<perlbug> program
included with your release. Be sure to trim your bug down to a tiny but
sufficient test case. Your bug report, along with the output of C<perl -V>,
-will be sent off to perlbug@perl.org to be analysed by the Perl porting team.
+will be sent off to C<perlbug@perl.org> to be analysed by the Perl porting team.
If the bug you are reporting has security implications which make it
inappropriate to send to a publicly archived mailing list, then see
https://perl5.git.perl.org / perl5.git / blobdiff