Change error wording for \o{}

[perl5.git] / pod / perldelta.pod

diff --git a/pod/perldelta.pod b/pod/perldelta.pod
index 3f70975..7a013af 100644 (file)
--- a/pod/perldelta.pod
+++ b/pod/perldelta.pod
@@ -2,333 +2,507 @@
 
 =head1 NAME
 
 
 =head1 NAME
 

-perldelta - what is new for perl v5.29.6
+[ 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 v5.29.9

 
 =head1 DESCRIPTION
 
 
 =head1 DESCRIPTION
 

-This document describes differences between the 5.29.5 release and the 5.29.6
+This document describes differences between the 5.29.8 release and the 5.29.9

 release.
 
 release.
 

-If you are upgrading from an earlier release such as 5.29.4, first read
-L<perl5295delta>, which describes differences between 5.29.4 and 5.29.5.
+If you are upgrading from an earlier release such as 5.29.7, first read
+L<perl5298delta>, which describes differences between 5.29.7 and 5.29.8.
+
+=head1 Notice
+
+XXX Any important notices here

 
 =head1 Core Enhancements
 
 
 =head1 Core Enhancements
 

-=head2 The upper limit C<"n"> specifiable in a regular expression
-quantifier of the form C<"{m,n}"> has been doubled to 65534
+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.
+
+[ List each enhancement as a =head2 entry ]
+
+=head2 Wildcards in Unicode property value specifications are now
+partially supported
+
+You can now do something like this in a regular expression pattern
+
+ qr! \p{nv= /(?x) \A [0-5] \z / }!
+
+which matches all Unicode code points which have numeric value is
+between 0 and 5 inclusive.
+
+This marks another step in implementing the regular expression features
+the Unicode Consortium suggests.
+
+Most properties are supported, with the remainder planned for 5.32.
+Details are in L<perlunicode/Wildcards in Property Values>.
+
+=head2 qr'\N{name}' is now supported
+
+Previously it was an error to evaluate a named character C<\N{...}>
+within a single quoted regular expression pattern (whose evaluation is
+deferred from the normal place).  This restriction is now removed.
+
+=head2 Unicode 12.0 is supported
+
+For details, see L<https://www.unicode.org/versions/Unicode12.0.0/>.
+
+Because of a change in Unicode release cycles, Perl jumps from Unicode
+10.0 in Perl 5.28 to Unicode 12.0 in Perl 5.30.
+
+=head2 It is now possible to compile perl to always use thread-safe
+locale operations.
+
+Previously, these calls were only used when the perl was compiled to be
+multi-threaded.  To always enable them, add
+
+ -Accflags='-DUSE_THREAD_SAFE_LOCALE'

 
 

-The meaning of an unbounded upper quantifier C<"{m,}"> remains unchanged.
-It matches 2**31 - 1 times on most platforms, and more on ones where a C
-language short variable is more than 4 bytes long.
+to your F<Configure> flags.

 
 

-The text above is what perl5294delta should have said.  Instead it said
-"The maximum number of times a pattern can match has been doubled to 65535"
-That statement was wrong.  Try to forget you ever saw it.

 
 =head1 Security
 
 
 =head1 Security
 

-=head2 [CVE-2018-18312] Heap-buffer-overflow write in S_regatom (regcomp.c)
+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.

 
 

-A crafted regular expression could cause heap-buffer-overflow write during
-compilation, potentially allowing arbitrary code execution. (This was 
-actually fixed in 5.29.4, but not announced as a security fix at the time).
+[ List each security issue as a =head2 entry ]

 
 

-L<[perl #133423]|https://rt.perl.org/Ticket/Display.html?id=133423>
+=head2 Variable length lookbehind in regular expression pattern matching
+is now experimentally supported

 
 

-=head1 Performance Enhancements
+Using a lookbehind assertion (like C<(?<=foo)> or C<(?<!bar)> previously
+would generate an error and refuse to compile.  Now it compiles (if the
+maximum lookbehind is at most 255 characters), but raises a warning in
+the new C<experimental::vlb> warnings category.  This is to caution you
+that the precise behavior is subject to change based on feedback from
+use in the field.

 
 

-=over 4
+See L<perlre/(?<=pattern)> and L<perlre/(?<!pattern)>.

 
 

-=item *
+=head1 Incompatible Changes

 
 

-Optimization of C<IV> to C<UV> conversions.
-L<[perl #133677]|https://rt.perl.org/Ticket/Display.html?id=133677>.
+XXX For a release on a stable branch, this section aspires to be:

 
 

-=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.

 
 

-Speed up of the integer stringification algorithm by processing
-two digits at a time instead of one.
-L<[perl #133691]|https://rt.perl.org/Ticket/Display.html?id=133691>.
+[ List each incompatible change as a =head2 entry ]

 
 

-=item *
+=head2 C<pack()> no longer can return malformed UTF-8

 
 

-Improvements based on LGTM analysis and recommendation.
-(L<https://lgtm.com/projects/g/Perl/perl5/alerts/?mode=tree>). 
-L<[perl #133686]|https://rt.perl.org/Ticket/Display.html?id=133686>.
-L<[perl #133699]|https://rt.perl.org/Ticket/Display.html?id=133699>.
+It croaks if it would otherwise return a UTF-8 string that contains
+malformed UTF-8.  This protects agains potential security threats.  This
+is considered a bug fix as well ([perl #131642]).

 
 

-=item *
+=head2 Any set of digits in the Common script are legal in a script run
+of another script
+
+There are several sets of digits in the Common script.  C<[0-9]> is the
+most familiar.  But there are also C<[\x{FF10}-\x{FF19}]> (FULLWIDTH
+DIGIT ZERO - FULLWIDTH DIGIT NINE), and several sets for use in
+mathematical notation, such as the MATHEMATICAL DOUBLE-STRUCK DIGITs.
+Any of these sets should be able to appear in script runs of, say,
+Greek.  But the design of 5.30 overlooked all but the ASCII digits
+C<[0-9]>, so the design was flawed.  This has been fixed, so is both a
+bug fix and an incompatibility. [perl #133547]
+
+All digits in a run still have to come from the same set of ten digits.
+
+=head1 Deprecations
+
+XXX Any deprecated features, syntax, modules etc. should be listed here.
+
+=head2 Module removals
+
+XXX Remove this section if not applicable.
+
+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.
+
+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.
+
+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.
+
+=over

 
 

-Code optimizations in F<regcomp.c>, F<regcomp.h>, F<regexec.c>.
+=item XXX
+
+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.

 
 =back
 
 
 =back
 

-=head1 Modules and Pragmata
+[ List each other deprecation as a =head2 entry ]

 
 

-=head2 Updated Modules and Pragmata
+=head1 Performance Enhancements
+
+XXX Changes which enhance performance without changing behaviour go here.
+There may well be none in a stable release.
+
+[ List each enhancement as an =item entry ]

 
 =over 4
 
 =item *
 
 
 =over 4
 
 =item *
 

-L<Config::Perl::V>. has been upgraded from version 0.30 to 0.32. This was due
-to a new configuration variable that has influence on binary compatibility:
-C<USE_THREAD_SAFE_LOCALE>.
+XXX

 
 

-=item *
+=back

 
 

-L<ExtUtils::ParseXS> has been upgraded from version 3.39 to 3.40.
-C<OUTLIST> parameters are no longer incorrectly included in the
-automatically generated function prototype.  [perl #133654]
+=head1 Modules and Pragmata
+
+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.
+
+The list of new and updated modules is modified automatically as part of
+preparing a Perl release, so the only reason to manually add entries here is if
+you're summarising the important changes in the module update. (Also, if the
+manually-added details don't match the automatically-generated ones, the
+release manager will have to investigate the situation carefully.)
+
+[ Within each section, list entries as an =item entry ]
+
+=head2 New Modules and Pragmata
+
+=over 4

 
 =item *
 
 
 =item *
 

-L<File::Find> has been upgraded from version 1.34 to 1.35.
-C<$File::Find::dont_use_nlink> now defaults to 1 on all
-platforms. [perl #133673]
+XXX Remove this section if not applicable.
+
+=back
+
+=head2 Updated Modules and Pragmata
+
+=over 4

 
 =item *
 
 
 =item *
 

-L<Module::CoreList> has been upgraded from version 5.20181120 to 5.20181218.
+L<perl5db.pl> has been upgraded from version 1.54 to 1.55.
+
+Debugging threaded code no longer deadlocks in C<DB::sub> nor
+C<DB::lsub>.

 
 =item *
 
 
 =item *
 

-L<POSIX> has been upgraded from version 1.85 to 1.86.
+L<PerlIO::encoding> has been upgraded from version 0.26 to 0.27.
+
+Warnings enabled by setting the C<WARN_ON_ERR> flag in
+C<$PerlIO::encoding::fallback> are now only produced if warnings are
+enabled with C<use warnings "utf8";> or setting C<$^W>.

 
 =item *
 
 
 =item *
 

-L<Storable> has been upgraded from version 3.13 to 3.14.
+L<threads::shared> has been upgraded from version 1.59 to 1.60.

 
 

-Storable no longer probes for recursion limits at build time.  [perl
-#133708] and others.
+Added support for extra tracing of locking, this requires a
+C<-DDEBUGGING> and extra compilation flags.

 
 

-Metasploit exploit code was included to test for CVE-2015-1992
-detection, this caused anti-virus detections on at least one AV suite.
-The exploit code has been removed and replaced with a simple
-functional test.  [perl #133706]
+=back

 
 

-=item *
+=head2 Removed Modules and Pragmata

 
 

-L<Test::Simple> has been upgraded from version 1.302140 to 1.302141.
+=over 4

 
 =item *
 
 
 =item *
 

-L<threads::shared> has been upgraded from version 1.58 to 1.59.
+XXX

 
 =back
 
 =head1 Documentation
 
 
 =back
 
 =head1 Documentation
 

+XXX Changes to files in F<pod/> go here.  Consider grouping entries by
+file and be sure to link to the appropriate page, e.g. L<perlfunc>.
+
+=head2 New Documentation
+
+XXX Changes which create B<new> files in F<pod/> go here.
+
+=head3 L<XXX>
+
+XXX Description of the purpose of the new file here
+

 =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>.
 
 =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>.
 

+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.
+

 Additionally, the following selected changes have been made:
 
 Additionally, the following selected changes have been made:
 

-=head3 L<perlfunc>
+=head3 L<XXX>
+
+=over 4
+
+=item *
+
+XXX Description of the change here
+
+=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>.
+
+XXX New or changed warnings emitted by the core's C<C> code go here.  Also
+include any changes in L<perldiag> that reconcile it to the C<C> code.
+
+=head2 New Diagnostics
+
+XXX Newly added diagnostic messages go under here, separated into New Errors
+and New Warnings
+
+=head3 New Errors

 
 =over 4
 
 =item *
 
 
 =over 4
 
 =item *
 

-Clarification of behaviour of C<reset EXPR>.
+XXX L<message|perldiag/"message">

 
 =back
 
 
 =back
 

-=head3 L<perlreref>
+=head3 New Warnings

 
 =over 4
 
 =item *
 
 
 =over 4
 
 =item *
 

-Clarification of the syntax of /(?(cond)yes)/.
+XXX L<message|perldiag/"message">

 
 =back
 
 
 =back
 

-=head3 L<perlop>
+=head2 Changes to Existing Diagnostics

 
 

-=over
+XXX Changes (i.e. rewording) of diagnostic messages go here
+
+=over 4

 
 =item *
 
 
 =item *
 

-We no longer have null (empty line) here doc terminators, so 
-L<perlop> should not refer to them.
+Specifying C<\o{}> without anything between the braces now yields the
+fatal error message "Empty \o{}".  Previously it was  "Number with no
+digits".  This means the same wording is used for this kind of error as
+with similar constructs such as C<\p{}>.

 
 =back
 
 
 =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 Changes to Existing 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. ]
+
+=head2 L<XXX>

 
 =over 4
 
 =item *
 
 
 =over 4
 
 =item *
 

-Under C<< -Dr >> (or C<< use re 'Debug' >>) the compiled regex engine
-program is displayed. It used two different spellings for I<< infinity >>,
-C<< INFINITY >>, and C<< INFTY >>. It now uses the latter exclusively,
-as that spelling has been around the longest.
+XXX

 
 =back
 
 
 =back
 

-=head1 Utility Changes
+=head1 Configuration and Compilation

 
 

-=head2 L<xsubpp>
+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.
+
+[ List changes as an =item entry ].

 
 =over 4
 
 =item *
 
 
 =over 4
 
 =item *
 

-The generated prototype (with C<< PROTOTYPES: ENABLE >>) would include
-C<< OUTLIST >> parameters, but these aren't arguments to the perl function.
-This has been rectified.
-L<[perl #133654]|https://rt.perl.org/Ticket/Display.html?id=133654>.
+XXX

 
 =back
 
 =head1 Testing
 
 
 =back
 
 =head1 Testing
 

+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.
+
+XXX If there were no significant test changes, say this:
+
+Tests were added and changed to reflect the other additions and changes
+in this release.
+
+XXX If instead there were significant changes, say this:
+

 Tests were added and changed to reflect the other additions and
 changes in this release.  Furthermore, these significant changes were
 made:
 
 Tests were added and changed to reflect the other additions and
 changes in this release.  Furthermore, these significant changes were
 made:
 

+[ List each test improvement as an =item entry ]
+

 =over 4
 
 =item *
 
 =over 4
 
 =item *
 

-Some tests in F<< t/io/eintr.t >> caused the process to hang on
-pre-16 Darwin. These tests are skipped for those version of Darwin.
+XXX

 
 =back
 
 =head1 Platform Support
 
 
 =back
 
 =head1 Platform Support
 

-=head2 Platform-Specific Notes
+XXX Any changes to platform support should be listed in the sections below.

 
 

-=over 4
+[ Within the sections, list each platform as an =item entry with specific
+changes as paragraphs below it. ]

 
 

-=item Cygwin
+=head2 New Platforms

 
 

-Cygwin doesn't make C<< cuserid >> visible.
+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.

 
 

-=item Win32 Mingw
+=over 4
+
+=item XXX-some-platform

 
 

-C99 math functions are now available.
+XXX

 
 =back
 
 
 =back
 

-=head1 Internal Changes
+=head2 Discontinued Platforms

 
 

-=over 4
+XXX List any platforms that this version of perl no longer compiles on.

 
 

-=item *
-
-Two new regnodes have been introduced C<< EXACT_ONLY8 >>, and
-C<< EXACTFU_ONLY8 >>. They're equivalent to C<< EXACT >> and C<< EXACTFU >>,
-except that they contain a code point which requires UTF-8 to
-represent/match. Hence, if the target string isn't UTF-8, we know
-it can't possibly match, without needing to try.
+=over 4

 
 

-=item *
+=item XXX-some-platform

 
 

-C<< print_bytes_for_locale() >> is now defined if C<< DEBUGGING >>,
-Prior, it didn't get defined unless C<< LC_COLLATE >> was defined
-on the platform.
+XXX

 
 =back
 
 
 =back
 

-=head1 Selected Bug Fixes
+=head2 Platform-Specific Notes
+
+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.

 
 =over 4
 
 
 =over 4
 

-=item *
+=item XXX-some-platform

 
 

-If an in-place edit is still in progress during global destruction and
-the process exit code (as stored in C<$?>) is zero, perl will now
-treat the in-place edit as successful, replacing the input file with
-any output produced.
+XXX

 
 

-This allows code like:
+=back

 
 

-  perl -i -ne 'print "Foo"; last'
+=head1 Internal Changes

 
 

-to replace the input file, while code like:
+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.

 
 

-  perl -i -ne 'print "Foo"; die'
+[ List each change as an =item entry ]

 
 

-will not.  Partly resolves
-L<[perl #133659]|https://rt.perl.org/Ticket/Display.html?id=133659>.
+=over 4

 
 =item *
 
 
 =item *
 

-A regression in 5.28 caused the following code to fail
+Added C<newSVsv_nomg()> to copy a SV without processing get magic on
+the source.  [perl #132964]
+
+=back
+
+=head1 Selected Bug Fixes

 
 

- close(STDIN); open(CHILD, "|wc -l")'
+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>.

 
 

-because the child's stdin would be closed on exec. This has now been fixed.
+[ List each fix as an =item entry ]
+
+=over 4

 
 =item *
 
 
 =item *
 

-Fixed an issue where compiling a regexp containing both compile-time
-and run-time code blocks could lead to trying to compile something
-which is invalid syntax.
+C<pack()> no longer can return malformed UTF-8.  It croaks if it would
+otherwise return a UTF-8 string that contains malformed UTF-8.  This
+protects agains potential security threats.  [perl #131642]

 
 =item *
 
 
 =item *
 

-Fixed build failures with C<< -DNO_LOCALE_NUMERIC >> and
-C<< -DNO_LOCALE_COLLATE >>.
-L<[perl #133696]|https://rt.perl.org/Ticket/Display.html?id=133696>.
+See L</Any set of digits in the Common script are legal in a script run
+of another script>.

 
 

-=item *
+=back
+
+=head1 Known Problems

 
 

-Prevent the tests in F<< ext/B/t/strict.t >> from being skipped.
-L<[perl #133713]|https://rt.perl.org/Ticket/Display.html?id=133713>.
+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.
+
+[ List each fix as an =item entry ]
+
+=over 4

 
 =item *
 
 
 =item *
 

-C<< /di >> nodes ending or beginning in I<s> are now C<< EXACTF >>. We do not
-want two C<< EXACTFU >> to be joined together during optimization,
-and to form a C<< ss >>, C<< sS >>, C<< Ss >> or C<< SS >> sequence;
-they are the only multi-character sequences which may match differently
-under C<< /ui >> and C<< /di >>. 
+XXX

 
 =back
 
 
 =back
 

-=head1 Acknowledgements
+=head1 Errata From Previous Releases
+
+=over 4

 
 

-Perl 5.29.6 represents approximately 4 weeks of development since Perl
-5.29.5 and contains approximately 5,000 lines of changes across 230 files
-from 19 authors.
+=item *
+
+XXX Add anything here that we forgot to add, or were mistaken about, in
+the perldelta of a previous release.

 
 

-Excluding auto-generated files, documentation and release tools, there were
-approximately 2,600 lines of changes to 150 .pm, .t, .c and .h files.
+=back

 
 

-Perl continues to flourish into its fourth decade thanks to a vibrant
-community of users and developers. The following people are known to have
-contributed the improvements that became Perl 5.29.6:
+=head1 Obituary

 
 

-Aaron Crane, Abigail, Dagfinn Ilmari Mannsåker, David Mitchell, Dominic
-Hargreaves, E. Choroba, Eugen Konkov, H.Merijn Brand, James E Keenan, Jerry
-D. Hedden, Karen Etheridge, Karl Williamson, Leon Timmermans, Niko Tyni,
-Petr Písař, Sisyphus, Steve Hay, Tomasz Konojacki, Tony Cook.
+XXX If any significant core contributor or member of the CPAN community has
+died, add a short obituary here.

 
 

-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 v5.29.8..HEAD

 
 =head1 Reporting Bugs
 
 
 =head1 Reporting Bugs