Create new perldelta for 5.25.4

4 files changed, 681 insertions, 270 deletions

diff --git a/pod/.gitignore b/pod/.gitignore
index 286d32d0c6..50266bbeab 100644
--- a/pod/.gitignore
+++ b/pod/.gitignore
@@ -53,7 +53,7 @@
 /roffitall
 
 # generated
-/perl5253delta.pod
+/perl5254delta.pod
 /perlapi.pod
 /perlintern.pod
 *.html
diff --git a/pod/perl.pod b/pod/perl.pod
index 0cbaa8d990..f8bf742daa 100644
--- a/pod/perl.pod
+++ b/pod/perl.pod
@@ -180,6 +180,7 @@ aux c2ph h2ph h2xs perlbug pl2pm pod2html pod2man splain xsubpp
 
     perlhist		Perl history records
     perldelta		Perl changes since previous version
+    perl5253delta	Perl changes in version 5.25.3
     perl5252delta	Perl changes in version 5.25.2
     perl5251delta	Perl changes in version 5.25.1
     perl5250delta	Perl changes in version 5.25.0
diff --git a/pod/perl5253delta.pod b/pod/perl5253delta.pod
new file mode 100644
index 0000000000..bc1b3758b5
--- /dev/null
+++ b/pod/perl5253delta.pod
@@ -0,0 +1,492 @@
+=encoding utf8
+
+=head1 NAME
+
+perl5253delta - what is new for perl v5.25.3
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.25.2 release and the 5.25.3
+release.
+
+If you are upgrading from an earlier release such as 5.25.1, first read
+L<perl5252delta>, which describes differences between 5.25.1 and 5.25.2.
+
+=head1 Core Enhancements
+
+=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>).  As of now, Perl uses this improved
+version when a property is specified as just C<\p{I<script>}>.  The meaning of
+compound forms, like C<\p{sc=I<script>}> are unchanged.  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.  See L<perlunicode/Scripts>.
+
+=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 slightly more detail.
+
+=head1 Incompatible Changes
+
+=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<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 C<Hash::Util::bucket_ratio()>
+which provides the same behavior as C<scalar(%hash)> provided prior to Perl
+5.25.
+
+=head1 Modules and Pragmata
+
+=head2 Updated Modules and Pragmata
+
+=over 4
+
+=item *
+
+L<bignum> has been upgraded from version 0.42 to 0.43.
+
+=item *
+
+L<Data::Dumper> has been upgraded from version 2.160 to 2.161.
+
+=item *
+
+L<Devel::PPPort> has been upgraded from version 3.32 to 3.35.
+
+=item *
+
+L<Encode> has been upgraded from version 2.80 to 2.84.
+
+=item *
+
+L<encoding> has been upgraded from version 2.17 to 2.17_01.
+
+This module's default mode is no longer supported as of Perl 5.25.3.  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 as of Perl 5.25.3.  It emits a warning to
+that effect and then does nothing.
+
+=item *
+
+L<ExtUtils::ParseXS> has been upgraded from version 3.32 to 3.33.
+
+=item *
+
+L<ExtUtils::Typemaps> has been upgraded from version 3.32 to 3.33.
+
+=item *
+
+L<feature> has been upgraded from version 1.44 to 1.45.
+
+=item *
+
+L<Hash::Util> has been upgraded from version 0.19 to 0.20.
+
+=item *
+
+L<Math::BigInt> has been upgraded from version 1.999715 to 1.999726.
+
+=item *
+
+L<Math::BigInt::FastCalc> has been upgraded from version 0.40 to 0.42.
+
+=item *
+
+L<Math::BigRat> has been upgraded from version 0.260802 to 0.260804.
+
+=item *
+
+L<Module::CoreList> has been upgraded from version 5.20160620 to 5.20160720.
+
+=item *
+
+L<Parse::CPAN::Meta> has been upgraded from version 1.4417 to 1.4422.
+
+=item *
+
+L<Perl::OSType> has been upgraded from version 1.009 to 1.010.
+
+=item *
+
+L<Test::Simple> has been upgraded from version 1.302026 to 1.302045.
+
+=item *
+
+L<Time::HiRes> has been upgraded from version 1.9734 to 1.9739.
+
+=item *
+
+L<Unicode::UCD> has been upgraded from version 0.65 to 0.66.
+
+=item *
+
+L<version> has been upgraded from version 0.9916 to 0.9917.
+
+=item *
+
+L<warnings> has been upgraded from version 1.36 to 1.37.
+
+=item *
+
+L<XSLoader> has been upgraded from version 0.21 to 0.22, fixing a security hole
+in which binary files could be loaded from a path outside of
+L<C<@INC>|perlvar/@INC>.
+
+=back
+
+=head1 Documentation
+
+=head2 Changes to Existing Documentation
+
+=head3 L<perldata> and L<perltie>
+
+=over 4
+
+=item *
+
+Updated documentation of C<scalar(%hash)>.  See L</scalar(%hash) return
+signature changed> above.
+
+=back
+
+=head3 L<perlexperiment> and L<perlref>
+
+=over 4
+
+=item *
+
+Documented new feature: See L</Declaring a reference to a variable> above.
+
+=back
+
+=head3 L<perlfunc>
+
+=over 4
+
+=item *
+
+Clarified documentation of L<C<seek()>|perlfunc/seek>,
+L<C<tell()>|perlfunc/tell> and L<C<sysseek()>|perlfunc/sysseek>.
+L<[perl #128607]|https://rt.perl.org/Public/Bug/Display.html?id=128607>
+
+=item *
+
+Removed obsolete documentation of L<C<study()>|perlfunc/study>.
+
+=back
+
+=head3 L<perlunicode>
+
+=over 4
+
+=item *
+
+Documented change to C<\p{I<script>}> to now use the improved Script_Extensions
+property.  See L</Use of \p{script} uses the improved Script_Extensions
+property> above.
+
+=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 *
+
+Removed obsolete documentation of C<${^ENCODING}>.  See L</${^ENCODING} has
+been removed> above.
+
+=back
+
+=head1 Diagnostics
+
+The following additions or changes have been made to diagnostic output,
+including warnings and fatal error messages.  For the complete list of
+diagnostic messages, see L<perldiag>.
+
+=head2 New Diagnostics
+
+=head3 New Errors
+
+=over 4
+
+=item *
+
+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";
+
+=back
+
+=head3 New Warnings
+
+=over 4
+
+=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|perldiag/"${^ENCODING} is no longer supported">
+
+(D deprecated) The special variable C<${^ENCODING}>, formerly used to implement
+the C<encoding> pragma, is no longer supported as of Perl 5.26.0.
+
+=back
+
+=head1 Configuration and Compilation
+
+=over 4
+
+=item *
+
+F<Configure> now aborts if both "-Duselongdouble" and "-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 "-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 "-DPERL_GLOBAL_STRUCT" or "-DPERL_GLOBAL_STRUCT_PRIVATE" have
+been fixed (by disabling Thread Safety Analysis for these configurations).
+
+=back
+
+=head1 Testing
+
+=over 4
+
+=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/anyof.t>, has been added to test that the ANYOF nodes
+generated by bracketed character classes are as expected.
+
+=back
+
+=head1 Platform Support
+
+=head2 Platform-Specific Notes
+
+=over 4
+
+=item VAX
+
+VAX floating point formats are now supported.
+
+=back
+
+=head1 Selected Bug Fixes
+
+=over 4
+
+=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 (e.g., C<delete $My::{"Foo::"};
+\&My::Foo::foo>) no longer crashes.  It had begun crashing in Perl 5.18.
+L<[perl #128532]|https://rt.perl.org/Public/Bug/Display.html?id=128532>
+
+=item *
+
+Some obscure cases of subroutines and file handles being freed at the same time
+could result in crashes, but have been fixed.  The crash was introduced in Perl
+5.22.
+L<[perl #128597]|https://rt.perl.org/Public/Bug/Display.html?id=128597>
+
+=item *
+
+Code that looks for a variable name associated with an uninitialized value
+could cause an assertion in cases where magic is involved, such as
+C<$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, 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</(?<=/> and C</(?<!/>.  This has now been fixed.
+L<[perl #128170]|https://rt.perl.org/Public/Bug/Display.html?id=128170>
+
+=back
+
+=head1 Errata From Previous Releases
+
+=over 4
+
+=item *
+
+Parsing bad POSIX charclasses no longer leaks memory.  This was fixed in Perl
+5.25.2
+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 5.24.0.
+L<[perl #126182]|https://rt.perl.org/Public/Bug/Display.html?id=126182>
+
+=back
+
+=head1 Acknowledgements
+
+Perl 5.25.3 represents approximately 4 weeks of development since Perl 5.25.2
+and contains approximately 67,000 lines of changes across 510 files from 25
+authors.
+
+Excluding auto-generated files, documentation and release tools, there were
+approximately 40,000 lines of changes to 290 .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 5.25.3:
+
+Aaron Crane, Ævar Arnfjörð Bjarmason, Alex Vandiver, Aristotle Pagaltzis,
+Chad Granum, Chris 'BinGOs' Williams, Chris Lamb, Craig A. Berry, Dan Collins,
+David Mitchell, Father Chrysostomos, H.Merijn Brand, Jarkko Hietaniemi, Karl
+Williamson, Lukas Mai, Matthew Horsfall, Salvador Fandiño, Sawyer X,
+Sébastien Aperghis-Tramoni, Steffen Müller, Steve Hay, Todd Rinaldo, Tony
+Cook, Unicode Consortium, Yves Orton.
+
+The list above is almost certainly incomplete as it is automatically generated
+from version control history.  In particular, it does not include the names of
+the (very much appreciated) contributors who reported issues to the Perl bug
+tracker.
+
+Many of the changes included in this version originated in the CPAN modules
+included in Perl's core.  We're grateful to the entire CPAN community for
+helping Perl to flourish.
+
+For a more complete list of all of Perl's historical contributors, please see
+the F<AUTHORS> file in the Perl source distribution.
+
+=head1 Reporting Bugs
+
+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
+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.
+
+If the bug you are reporting has security implications which make it
+inappropriate to send to a publicly archived mailing list, then see
+L<perlsec/SECURITY VULNERABILITY CONTACT INFORMATION> for details of how to
+report the issue.
+
+=head1 SEE ALSO
+
+The F<Changes> file for an explanation of how to view exhaustive details on
+what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/pod/perldelta.pod b/pod/perldelta.pod
index 2607446c7d..1fd242a02d 100644
--- a/pod/perldelta.pod
+++ b/pod/perldelta.pod
@@ -2,414 +2,359 @@
 
 =head1 NAME
 
-perldelta - what is new for perl v5.25.3
+[ this is a template for a new perldelta file.  Any text flagged as XXX needs
+to be processed before release. ]
+
+perldelta - what is new for perl v5.25.4
 
 =head1 DESCRIPTION
 
-This document describes differences between the 5.25.2 release and the 5.25.3
+This document describes differences between the 5.25.3 release and the 5.25.4
 release.
 
-If you are upgrading from an earlier release such as 5.25.1, first read
-L<perl5252delta>, which describes differences between 5.25.1 and 5.25.2.
-
-=head1 Core Enhancements
+If you are upgrading from an earlier release such as 5.25.2, first read
+L<perl5253delta>, which describes differences between 5.25.2 and 5.25.3.
 
-=head2 Unicode 9.0 is now supported
+=head1 Notice
 
-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.
+XXX Any important notices here
 
-=head2 Use of C<\p{I<script>}> uses the improved Script_Extensions property
+=head1 Core Enhancements
 
-Unicode 6.0 introduced an improved form of the Script (C<sc>) property, and
-called it Script_Extensions (C<scx>).  As of now, Perl uses this improved
-version when a property is specified as just C<\p{I<script>}>.  The meaning of
-compound forms, like C<\p{sc=I<script>}> are unchanged.  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.  See L<perlunicode/Scripts>.
+XXX New core language features go here.  Summarize user-visible core language
+enhancements.  Particularly prominent performance optimisations could go
+here, but most should go in the L</Performance Enhancements> section.
 
-=head2 Declaring a reference to a variable
+[ List each enhancement as a =head2 entry ]
 
-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:
+=head1 Security
 
-    use experimental 'refaliasing', 'declared_refs';
-    my \$a = \$b;
+XXX Any security-related notices go here.  In particular, any security
+vulnerabilities closed should be noted here rather than in the
+L</Selected Bug Fixes> section.
 
-See L<perlref/Assigning to References> for slightly more detail.
+[ List each security issue as a =head2 entry ]
 
 =head1 Incompatible Changes
 
-=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<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 C<Hash::Util::bucket_ratio()>
-which provides the same behavior as C<scalar(%hash)> provided prior to Perl
-5.25.
+XXX For a release on a stable branch, this section aspires to be:
 
-=head1 Modules and Pragmata
-
-=head2 Updated Modules and Pragmata
-
-=over 4
-
-=item *
+    There are no changes intentionally incompatible with 5.XXX.XXX
+    If any exist, they are bugs, and we request that you submit a
+    report.  See L</Reporting Bugs> below.
 
-L<bignum> has been upgraded from version 0.42 to 0.43.
+[ List each incompatible change as a =head2 entry ]
 
-=item *
+=head1 Deprecations
 
-L<Data::Dumper> has been upgraded from version 2.160 to 2.161.
+XXX Any deprecated features, syntax, modules etc. should be listed here.
 
-=item *
+=head2 Module removals
 
-L<Devel::PPPort> has been upgraded from version 3.32 to 3.35.
+XXX Remove this section if inapplicable.
 
-=item *
+The following modules will be removed from the core distribution in a
+future release, and will at that time need to be installed from CPAN.
+Distributions on CPAN which require these modules will need to list them as
+prerequisites.
 
-L<Encode> has been upgraded from version 2.80 to 2.84.
+The core versions of these modules will now issue C<"deprecated">-category
+warnings to alert you to this fact.  To silence these deprecation warnings,
+install the modules in question from CPAN.
 
-=item *
+Note that these are (with rare exceptions) fine modules that you are encouraged
+to continue to use.  Their disinclusion from core primarily hinges on their
+necessity to bootstrapping a fully functional, CPAN-capable Perl installation,
+not usually on concerns over their design.
 
-L<encoding> has been upgraded from version 2.17 to 2.17_01.
+=over
 
-This module's default mode is no longer supported as of Perl 5.25.3.  It now
-dies when imported, unless the C<Filter> option is being used.
+=item XXX
 
-=item *
+XXX Note that deprecated modules should be listed here even if they are listed
+as an updated module in the L</Modules and Pragmata> section.
 
-L<encoding::warnings> has been upgraded from version 0.12 to 0.13.
+=back
 
-This module is no longer supported as of Perl 5.25.3.  It emits a warning to
-that effect and then does nothing.
+[ List each other deprecation as a =head2 entry ]
 
-=item *
+=head1 Performance Enhancements
 
-L<ExtUtils::ParseXS> has been upgraded from version 3.32 to 3.33.
+XXX Changes which enhance performance without changing behaviour go here.
+There may well be none in a stable release.
 
-=item *
+[ List each enhancement as a =item entry ]
 
-L<ExtUtils::Typemaps> has been upgraded from version 3.32 to 3.33.
+=over 4
 
 =item *
 
-L<feature> has been upgraded from version 1.44 to 1.45.
+XXX
 
-=item *
+=back
 
-L<Hash::Util> has been upgraded from version 0.19 to 0.20.
+=head1 Modules and Pragmata
 
-=item *
+XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
+go here.  If Module::CoreList is updated, generate an initial draft of the
+following sections using F<Porting/corelist-perldelta.pl>.  A paragraph summary
+for important changes should then be added by hand.  In an ideal world,
+dual-life modules would have a F<Changes> file that could be cribbed.
 
-L<Math::BigInt> has been upgraded from version 1.999715 to 1.999726.
+[ Within each section, list entries as a =item entry ]
 
-=item *
+=head2 New Modules and Pragmata
 
-L<Math::BigInt::FastCalc> has been upgraded from version 0.40 to 0.42.
+=over 4
 
 =item *
 
-L<Math::BigRat> has been upgraded from version 0.260802 to 0.260804.
-
-=item *
+XXX
 
-L<Module::CoreList> has been upgraded from version 5.20160620 to 5.20160720.
+=back
 
-=item *
+=head2 Updated Modules and Pragmata
 
-L<Parse::CPAN::Meta> has been upgraded from version 1.4417 to 1.4422.
+=over 4
 
 =item *
 
-L<Perl::OSType> has been upgraded from version 1.009 to 1.010.
+L<XXX> has been upgraded from version A.xx to B.yy.
 
-=item *
-
-L<Test::Simple> has been upgraded from version 1.302026 to 1.302045.
+=back
 
-=item *
+=head2 Removed Modules and Pragmata
 
-L<Time::HiRes> has been upgraded from version 1.9734 to 1.9739.
+=over 4
 
 =item *
 
-L<Unicode::UCD> has been upgraded from version 0.65 to 0.66.
+XXX
 
-=item *
+=back
 
-L<version> has been upgraded from version 0.9916 to 0.9917.
+=head1 Documentation
 
-=item *
+XXX Changes to files in F<pod/> go here.  Consider grouping entries by
+file and be sure to link to the appropriate page, e.g. L<perlfunc>.
 
-L<warnings> has been upgraded from version 1.36 to 1.37.
+=head2 New Documentation
 
-=item *
+XXX Changes which create B<new> files in F<pod/> go here.
 
-L<XSLoader> has been upgraded from version 0.21 to 0.22, fixing a security hole
-in which binary files could be loaded from a path outside of
-L<C<@INC>|perlvar/@INC>.
+=head3 L<XXX>
 
-=back
-
-=head1 Documentation
+XXX Description of the purpose of the new file here
 
 =head2 Changes to Existing Documentation
 
-=head3 L<perldata> and L<perltie>
+XXX Changes which significantly change existing files in F<pod/> go here.
+However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
+section.
+
+=head3 L<XXX>
 
 =over 4
 
 =item *
 
-Updated documentation of C<scalar(%hash)>.  See L</scalar(%hash) return
-signature changed> above.
+XXX Description of the change here
 
 =back
 
-=head3 L<perlexperiment> and L<perlref>
+=head1 Diagnostics
 
-=over 4
+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 *
+XXX New or changed warnings emitted by the core's C<C> code go here.  Also
+include any changes in L<perldiag> that reconcile it to the C<C> code.
 
-Documented new feature: See L</Declaring a reference to a variable> above.
+=head2 New Diagnostics
 
-=back
+XXX Newly added diagnostic messages go under here, separated into New Errors
+and New Warnings
 
-=head3 L<perlfunc>
+=head3 New Errors
 
 =over 4
 
 =item *
 
-Clarified documentation of L<C<seek()>|perlfunc/seek>,
-L<C<tell()>|perlfunc/tell> and L<C<sysseek()>|perlfunc/sysseek>.
-L<[perl #128607]|https://rt.perl.org/Public/Bug/Display.html?id=128607>
-
-=item *
-
-Removed obsolete documentation of L<C<study()>|perlfunc/study>.
+XXX L<message|perldiag/"message">
 
 =back
 
-=head3 L<perlunicode>
+=head3 New Warnings
 
 =over 4
 
 =item *
 
-Documented change to C<\p{I<script>}> to now use the improved Script_Extensions
-property.  See L</Use of \p{script} uses the improved Script_Extensions
-property> above.
-
-=item *
-
-Updated the text to correspond with changes in Unicode UTS#18, concerning
-regular expressions, and Perl compatibility with what it says.
+XXX L<message|perldiag/"message">
 
 =back
 
-=head3 L<perlvar>
+=head2 Changes to Existing Diagnostics
+
+XXX Changes (i.e. rewording) of diagnostic messages go here
 
 =over 4
 
 =item *
 
-Removed obsolete documentation of C<${^ENCODING}>.  See L</${^ENCODING} has
-been removed> above.
+XXX Describe change here
 
 =back
 
-=head1 Diagnostics
+=head1 Utility Changes
 
-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>.
+XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go here.
+Most of these are built within the directory F<utils>.
 
-=head2 New Diagnostics
+[ List utility changes as a =head2 entry for each utility and =item
+entries for each change
+Use L<XXX> with program names to get proper documentation linking. ]
 
-=head3 New Errors
+=head2 L<XXX>
 
 =over 4
 
 =item *
 
-L<The experimental declared_refs feature is not enabled|perldiag/"The experimental declared_refs feature is not enabled">
+XXX
 
-(F) To declare references to variables, as in C<my \%x>, you must first enable
-the feature:
+=back
 
-    no warnings "experimental::declared_refs";
-    use feature "declared_refs";
+=head1 Configuration and Compilation
 
-=back
+XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
+go here.  Any other changes to the Perl build process should be listed here.
+However, any platform-specific changes should be listed in the
+L</Platform Support> section, instead.
 
-=head3 New Warnings
+[ List changes as a =item entry ].
 
 =over 4
 
 =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;
+XXX
 
-=item *
-
-L<C<${^ENCODING}> is no longer supported|perldiag/"${^ENCODING} is no longer supported">
+=back
 
-(D deprecated) The special variable C<${^ENCODING}>, formerly used to implement
-the C<encoding> pragma, is no longer supported as of Perl 5.26.0.
+=head1 Testing
 
-=back
+XXX Any significant changes to the testing of a freshly built perl should be
+listed here.  Changes which create B<new> files in F<t/> go here as do any
+large changes to the testing harness (e.g. when parallel testing was added).
+Changes to existing files in F<t/> aren't worth summarizing, although the bugs
+that they represent may be covered elsewhere.
 
-=head1 Configuration and Compilation
+[ List each test improvement as a =item entry ]
 
 =over 4
 
 =item *
 
-F<Configure> now aborts if both "-Duselongdouble" and "-Dusequadmath" are
-requested.
-L<[perl #126203]|https://rt.perl.org/Public/Bug/Display.html?id=126203>
+XXX
 
-=item *
+=back
 
-Fixed a bug in which F<Configure> could append "-quadmath" to the archname even
-if it was already present.
-L<[perl #128538]|https://rt.perl.org/Public/Bug/Display.html?id=128538>
+=head1 Platform Support
 
-=item *
+XXX Any changes to platform support should be listed in the sections below.
 
-Clang builds with "-DPERL_GLOBAL_STRUCT" or "-DPERL_GLOBAL_STRUCT_PRIVATE" have
-been fixed (by disabling Thread Safety Analysis for these configurations).
+[ Within the sections, list each platform as a =item entry with specific
+changes as paragraphs below it. ]
 
-=back
+=head2 New Platforms
 
-=head1 Testing
+XXX List any platforms that this version of perl compiles on, that previous
+versions did not.  These will either be enabled by new files in the F<hints/>
+directories, or new subdirectories and F<README> files at the top level of the
+source tree.
 
 =over 4
 
-=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 *
+=item XXX-some-platform
 
-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.
+XXX
 
 =back
 
-=head1 Platform Support
+=head2 Discontinued Platforms
 
-=head2 Platform-Specific Notes
+XXX List any platforms that this version of perl no longer compiles on.
 
 =over 4
 
-=item VAX
+=item XXX-some-platform
 
-VAX floating point formats are now supported.
+XXX
 
 =back
 
-=head1 Selected Bug Fixes
+=head2 Platform-Specific Notes
 
-=over 4
+XXX List any changes for specific platforms.  This could include configuration
+and compilation changes or changes in portability/compatibility.  However,
+changes within modules for platforms should generally be listed in the
+L</Modules and Pragmata> section.
 
-=item *
+=over 4
 
-An assertion failure with C<%: = 0> has been fixed.
-L<[perl #128238]|https://rt.perl.org/Public/Bug/Display.html?id=128238>
+=item XXX-some-platform
 
-=item *
+XXX
 
-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>
+=back
 
-=item *
+=head1 Internal Changes
 
-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>
+XXX Changes which affect the interface available to C<XS> code go here.  Other
+significant internal changes for future core maintainers should be noted as
+well.
 
-=item *
+[ List each change as a =item entry ]
 
-Vivifying a subroutine stub in a deleted stash (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>
+=over 4
 
 =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>
+XXX
 
-=item *
+=back
 
-Code that looks for a variable name associated with an uninitialized value
-could cause an assertion 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>
+=head1 Selected Bug Fixes
 
-=item *
+XXX Important bug fixes in the core language are summarized here.  Bug fixes in
+files in F<ext/> and F<lib/> are best summarized in L</Modules and Pragmata>.
+
+[ List each fix as a =item entry ]
 
-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>
+=over 4
 
 =item *
 
-Fixed an assertion triggered by some code that handles deprecated behavior in
-formats, e.g. in cases like this:
+XXX
+
+=back
 
-    format STDOUT =
-    @
-    0"$x"
+=head1 Known Problems
 
-L<[perl #128255]|https://rt.perl.org/Public/Bug/Display.html?id=128255>
+XXX Descriptions of platform agnostic bugs we know we can't fix go here.  Any
+tests that had to be C<TODO>ed for the release would be noted here.  Unfixed
+platform specific bugs also go here.
 
-=item *
+[ List each fix as a =item entry ]
 
-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>
+=over 4
 
 =item *
 
-Some regular expression parsing glitches could lead to assertion failures with
-regular expressions such as C</(?<=/> and C</(?<!/>.  This has now been fixed.
-L<[perl #128170]|https://rt.perl.org/Public/Bug/Display.html?id=128170>
+XXX
 
 =back
 
@@ -419,53 +364,26 @@ L<[perl #128170]|https://rt.perl.org/Public/Bug/Display.html?id=128170>
 
 =item *
 
-Parsing bad POSIX charclasses no longer leaks memory.  This was fixed in Perl
-5.25.2
-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 5.24.0.
-L<[perl #126182]|https://rt.perl.org/Public/Bug/Display.html?id=126182>
+XXX Add anything here that we forgot to add, or were mistaken about, in
+the perldelta of a previous release.
 
 =back
 
-=head1 Acknowledgements
-
-Perl 5.25.3 represents approximately 4 weeks of development since Perl 5.25.2
-and contains approximately 67,000 lines of changes across 510 files from 25
-authors.
+=head1 Obituary
 
-Excluding auto-generated files, documentation and release tools, there were
-approximately 40,000 lines of changes to 290 .pm, .t, .c and .h files.
+XXX If any significant core contributor has died, we've added a short obituary
+here.
 
-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 5.25.3:
-
-Aaron Crane, Ævar Arnfjörð Bjarmason, Alex Vandiver, Aristotle Pagaltzis,
-Chad Granum, Chris 'BinGOs' Williams, Chris Lamb, Craig A. Berry, Dan Collins,
-David Mitchell, Father Chrysostomos, H.Merijn Brand, Jarkko Hietaniemi, Karl
-Williamson, Lukas Mai, Matthew Horsfall, Salvador Fandiño, Sawyer X,
-Sébastien Aperghis-Tramoni, Steffen Müller, Steve Hay, Todd Rinaldo, Tony
-Cook, Unicode Consortium, Yves Orton.
-
-The list above is almost certainly incomplete as it is automatically generated
-from version control history.  In particular, it does not include the names of
-the (very much appreciated) contributors who reported issues to the Perl bug
-tracker.
+=head1 Acknowledgements
 
-Many of the changes included in this version originated in the CPAN modules
-included in Perl's core.  We're grateful to the entire CPAN community for
-helping Perl to flourish.
+XXX Generate this with:
 
-For a more complete list of all of Perl's historical contributors, please see
-the F<AUTHORS> file in the Perl source distribution.
+  perl Porting/acknowledgements.pl v5.25.3..HEAD
 
 =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 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
@@ -475,8 +393,8 @@ will be sent off to 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
-L<perlsec/SECURITY VULNERABILITY CONTACT INFORMATION> for details of how to
-report the issue.
+L<perlsec/SECURITY VULNERABILITY CONTACT INFORMATION>
+for details of how to report the issue.
 
 =head1 SEE ALSO