perldelta: merge in changes from perl5232delta

1 files changed, 211 insertions, 0 deletions

diff --git a/Porting/perl5240delta.pod b/Porting/perl5240delta.pod
index d9a4427e32..9ecfa5a0db 100644
--- a/Porting/perl5240delta.pod
+++ b/Porting/perl5240delta.pod
@@ -62,6 +62,20 @@ that are used as format fields, widths, and vector separators).
 
 =head1 Incompatible Changes
 
+=head2 Nested declarations are now disallowed
+
+A C<my>, C<our>, or C<state> declaration is no longer allowed inside
+of another C<my>, C<our>, or C<state> declaration.
+
+For example, these are now fatal:
+
+   my ($x, my($y));
+   our (my $x);
+
+L<[perl #125587]|https://rt.perl.org/Ticket/Display.html?id=125587>
+
+L<[perl #121058]|https://rt.perl.org/Ticket/Display.html?id=121058>
+
 =head2 The C</\C/> character class has been removed.
 
 This regular expression character class was deprecated in v5.20.0 and has
@@ -100,6 +114,53 @@ a scalar argument) has been deemed unsuccessful. It has now been removed;
 trying to use the feature (or to disable the C<experimental::autoderef>
 warning it previously triggered) now yields an exception.
 
+=head1 Deprecations
+
+=head2 sysread(), syswrite(), recv() and send() are deprecated on
+:utf8 handles
+
+The sysread(), recv(), syswrite() and send() operators
+are deprecated on handles that have the C<:utf8> layer, either
+explicitly, or implicitly, eg., with the C<:encoding(UTF-16LE)> layer.
+
+Both sysread() and recv() currently use only the C<:utf8> flag for the
+stream, ignoring the actual layers.  Since sysread() and recv() do no
+UTF-8 validation they can end up creating invalidly encoded scalars.
+
+Similarly, syswrite() and send() use only the C<:utf8> flag, otherwise
+ignoring any layers.  If the flag is set, both write the value UTF-8
+encoded, even if the layer is some different encoding, such as the
+example above.
+
+Ideally, all of these operators would completely ignore the C<:utf8>
+state, working only with bytes, but this would result in silently
+breaking existing code.  To avoid this a future version of perl will
+throw an exception when any of sysread(), recv(), syswrite() or send()
+are called on handle with the C<:utf8> layer.
+
+=head1 Performance Enhancements
+
+=over 4
+
+=item *
+
+Creating Perl debugger data structures (see L<perldebguts/"Debugger Internals">)
+for XSUBs and const subs has been removed.  This removed one glob/scalar combo
+for each unique C<.c> file that XSUBs and const subs came from.  On startup
+(C<perl -e"0">) about half a dozen glob/scalar debugger combos were created.
+Loading XS modules created more glob/scalar combos.  These things were created
+regardless if the perl debugger was being used or not, unlike for pure perl
+subs, and ignores that the perl debugger can not debug C code.
+
+=item *
+
+Single arguments in list assign are now slightly faster:
+
+  ($x) = (...);
+  (...) = ($x);
+
+=back
+
 =head1 Modules and Pragmata
 
 =head2 Updated Modules and Pragmata
@@ -243,6 +304,116 @@ exports anything.  [perl #125410]
 
 =back
 
+=head1 Documentation
+
+=head2 Changes to Existing Documentation
+
+=head3 L<perlpolicy>
+
+=over 4
+
+=item *
+
+This note has been added to perlpolicy:
+
+  While civility is required, kindness is encouraged; if you have any doubt
+  about whether you are being civil, simply ask yourself, "Am I being kind?"
+  and aspire to that.
+
+=back
+
+=head3 L<perlvar>
+
+=over 4
+
+=item *
+
+Use of C<$OLD_PERL_VERSION> is now discouraged.
+
+=back
+
+=head1 Diagnostics
+
+The following additions or changes have been made to diagnostic output,
+including warnings and fatal error messages.  For the complete list of
+diagnostic messages, see L<perldiag>.
+
+=head2 New Diagnostics
+
+=head3 New Errors
+
+=over 4
+
+=item *
+
+L<Can't redeclare "%s" in "%s"|perldiag/"Can't redeclare "%s" in "%s"">
+
+(F) A "my", "our" or "state" declaration was found within another declaration,
+such as C<my ($x, my($y), $z)> or C<our (my $x)>.
+
+=back
+
+=head3 New Warnings
+
+=over 4
+
+=item *
+
+L<%s() is deprecated on :utf8 handles|perldiag/"%s() is deprecated on :utf8 handles">
+
+(W deprecated) The sysread(), recv(), syswrite() and send() operators
+are deprecated on handles that have the C<:utf8> layer, either
+explicitly, or implicitly, eg., with the C<:encoding(UTF-16LE)> layer.
+
+Both sysread() and recv() currently use only the C<:utf8> flag for the
+stream, ignoring the actual layers.  Since sysread() and recv() do no
+UTF-8 validation they can end up creating invalidly encoded scalars.
+
+Similarly, syswrite() and send() use only the C<:utf8> flag, otherwise
+ignoring any layers.  If the flag is set, both write the value UTF-8
+encoded, even if the layer is some different encoding, such as the
+example above.
+
+Ideally, all of these operators would completely ignore the C<:utf8>
+state, working only with bytes, but this would result in silently
+breaking existing code.  To avoid this a future version of perl will
+throw an exception when any of sysread(), recv(), syswrite() or send()
+are called on handle with the C<:utf8> layer.
+
+=back
+
+=head2 Changes to Existing Diagnostics
+
+=over 4
+
+=item *
+
+The diagnostic C<< Hexadecimal float: internal error >> has been changed to
+C<< Hexadecimal float: internal error (%s) >> to include more information.
+
+=back
+
+=head1 Configuration and Compilation
+
+=over 4
+
+=item *
+
+F<Configure> should handle spaces in paths a little better.
+
+=back
+
+=head1 Testing
+
+=over 4
+
+=item *
+
+A new test (F<t/op/aassign.t>) has been added to test the list assignment operator
+C<OP_AASSIGN>.
+
+=back
+
 =head1 Platform Support
 
 =head2 Platform-Specific Notes
@@ -283,6 +454,20 @@ C<truncate($filename, $size)> now works for files over 4GB in size.
 
 =back
 
+=head1 Internal Changes
+
+=over 4
+
+=item *
+
+C<PL_sawalias> and C<GPf_ALIASED_SV> have been removed.
+
+=item *
+
+C<GvASSIGN_GENERATION> and C<GvASSIGN_GENERATION_set> have been removed.
+
+=back
+
 =head1 Selected Bug Fixes
 
 =over 4
@@ -330,6 +515,32 @@ C<alarm()> and C<sleep()> will now warn if the argument is a negative number
 and return undef. Previously they would pass the negative value to the
 underlying C function which may have set up a timer with a surprising value.
 
+=item *
+
+Perl can again be compiled with any Unicode version.  This used to
+(mostly) work, but was lost in v5.18 through v5.20.  The property
+C<Name_Alias> did not exist prior to Unicode 5.0.  L<Unicode::UCD>
+incorrectly said it did.  This has been fixed.
+
+=item *
+
+Very large code-points (beyond Unicode) in regular expressions no
+longer cause a buffer overflow in some cases when converted to UTF-8.
+L<[perl #125826]|https://rt.perl.org/Ticket/Display.html?id=125826>
+
+=item *
+
+The integer overflow check for the range operator (...) in list
+context now correctly handles the case where the size of the range is
+larger than the address space.  This could happen on 32-bits with
+-Duse64bitint.
+L<[perl #125781]|https://rt.perl.org/Ticket/Display.html?id=125781>
+
+=item *
+
+A crash with C<< %::=(); J->${\"::"} >> has been fixed.
+L<[perl #125541]|https://rt.perl.org/Ticket/Display.html?id=125541>
+
 =back
 
 =head1 Acknowledgements