[perl5.git] / pod / perl5299delta.pod

=encoding utf8

=head1 NAME

perl5299delta - what is new for perl v5.29.9

=head1 DESCRIPTION

This document describes differences between the 5.29.8 release and the 5.29.9
release.

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 Core Enhancements

=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'

to your F<Configure> flags.

=head2 Limited variable length lookbehind in regular expression pattern matching
is now experimentally supported

Using a lookbehind assertion (like C<(?<=foo?)> or C<(?<!ba{1,9}r)> 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.

See L<perlre/(?<=pattern)> and L<perlre/(?<!pattern)>.

=head1 Incompatible Changes

=head2 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.  This
is considered a bug fix as well ([perl #131642]).

=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 Modules and Pragmata

=head2 Updated Modules and Pragmata

=over 4

=item *

L<Devel::PPPort> has been upgraded from version 3.44 to 3.45.

=item *

L<Encode> has been upgraded from version 3.00 to 3.01.

=item *

L<ExtUtils::Manifest> has been upgraded from version 1.71 to 1.72.

=item *

L<JSON::PP> has been upgraded from version 4.00 to 4.02.

=item *

L<Module::CoreList> has been upgraded from version 5.20190220 to 5.20190320.

=item *

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 *

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 *

L<threads::shared> has been upgraded from version 1.59 to 1.60.

Added support for extra tracing of locking, this requires a
C<-DDEBUGGING> and extra compilation flags.

=item *

L<utf8> has been upgraded from version 1.21 to 1.22.

=item *

L<warnings> has been upgraded from version 1.43 to 1.44.

=item *

L<ExtUtils::CBuilder> has been upgraded from version 0.280230 to 0.280231.

=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 Changes to Existing Diagnostics

=over 4

=item *

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{}>.

=item *

Within the scope of the experimental feature C<use re 'strict'>,
specifying C<\x{}> without anything between the braces now yields the
fatal error message "Empty \x{}".  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{}>.  It is legal, though not wise
to have an empty C<\x> outside of C<re 'strict'>; it silently generates
a NUL character.

=back

=head1 Internal Changes

=over 4

=item *

Added C<newSVsv_nomg()> to copy a SV without processing get magic on
the source.  [perl #132964]

=back

=head1 Selected Bug Fixes

=over 4

=item *

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 *

See L</Any set of digits in the Common script are legal in a script run
of another script>.

=back

=head1 Acknowledgements

Perl 5.29.9 represents approximately 4 weeks of development since Perl
5.29.8 and contains approximately 47,000 lines of changes across 210 files
from 11 authors.

Excluding auto-generated files, documentation and release tools, there were
approximately 38,000 lines of changes to 71 .pm, .t, .c and .h files.

Perl continues to flourish into its fourth decade thanks to a vibrant
community of users and developers. The following people are known to have
contributed the improvements that became Perl 5.29.9:

Chris 'BinGOs' Williams, Craig A. Berry, Dagfinn Ilmari Mannsåker, Dan
Kogai, David Mitchell, Karen Etheridge, Karl Williamson, Nicolas R., Pali,
Tony Cook, Unicode Consortium.

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 Give Thanks

If you wish to thank the Perl 5 Porters for the work we had done in Perl 5,
you can do so by running the C<perlthanks> program:

    perlthanks

This will send an email to the Perl 5 Porters list with your show of thanks.

=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
Commit	Line	Data
ab6f2e91 ZE	1	=encoding utf8
	2
	3	=head1 NAME
	4
	5	perl5299delta - what is new for perl v5.29.9
	6
	7	=head1 DESCRIPTION
	8
	9	This document describes differences between the 5.29.8 release and the 5.29.9
	10	release.
	11
	12	If you are upgrading from an earlier release such as 5.29.7, first read
	13	L<perl5298delta>, which describes differences between 5.29.7 and 5.29.8.
	14
	15	=head1 Core Enhancements
	16
	17	=head2 Wildcards in Unicode property value specifications are now
	18	partially supported
	19
	20	You can now do something like this in a regular expression pattern
	21
	22	qr! \p{nv= /(?x) \A [0-5] \z / }!
	23
	24	which matches all Unicode code points which have numeric value is
	25	between 0 and 5 inclusive.
	26
	27	This marks another step in implementing the regular expression features
	28	the Unicode Consortium suggests.
	29
	30	Most properties are supported, with the remainder planned for 5.32.
	31	Details are in L<perlunicode/Wildcards in Property Values>.
	32
	33	=head2 qr'\N{name}' is now supported
	34
	35	Previously it was an error to evaluate a named character C<\N{...}>
	36	within a single quoted regular expression pattern (whose evaluation is
	37	deferred from the normal place). This restriction is now removed.
	38
	39	=head2 Unicode 12.0 is supported
	40
	41	For details, see L<https://www.unicode.org/versions/Unicode12.0.0/>.
	42
	43	Because of a change in Unicode release cycles, Perl jumps from Unicode
	44	10.0 in Perl 5.28 to Unicode 12.0 in Perl 5.30.
	45
	46	=head2 It is now possible to compile perl to always use thread-safe
	47	locale operations.
	48
	49	Previously, these calls were only used when the perl was compiled to be
	50	multi-threaded. To always enable them, add
	51
	52	-Accflags='-DUSE_THREAD_SAFE_LOCALE'
	53
	54	to your F<Configure> flags.
	55
5e6a22d7	56	=head2 Limited variable length lookbehind in regular expression pattern matching
ab6f2e91 ZE	57	is now experimentally supported
ab6f2e91 ZE	58
f6f85064	59	Using a lookbehind assertion (like C<(?<=foo?)> or C<(?<!ba{1,9}r)> previously
ab6f2e91 ZE	60	would generate an error and refuse to compile. Now it compiles (if the
	61	maximum lookbehind is at most 255 characters), but raises a warning in
	62	the new C<experimental::vlb> warnings category. This is to caution you
	63	that the precise behavior is subject to change based on feedback from
	64	use in the field.
	65
	66	See L<perlre/(?<=pattern)> and L<perlre/(?<!pattern)>.
	67
	68	=head1 Incompatible Changes
	69
	70	=head2 C<pack()> no longer can return malformed UTF-8
	71
	72	It croaks if it would otherwise return a UTF-8 string that contains
	73	malformed UTF-8. This protects agains potential security threats. This
	74	is considered a bug fix as well ([perl #131642]).
	75
	76	=head2 Any set of digits in the Common script are legal in a script run
	77	of another script
	78
	79	There are several sets of digits in the Common script. C<[0-9]> is the
	80	most familiar. But there are also C<[\x{FF10}-\x{FF19}]> (FULLWIDTH
	81	DIGIT ZERO - FULLWIDTH DIGIT NINE), and several sets for use in
	82	mathematical notation, such as the MATHEMATICAL DOUBLE-STRUCK DIGITs.
	83	Any of these sets should be able to appear in script runs of, say,
	84	Greek. But the design of 5.30 overlooked all but the ASCII digits
	85	C<[0-9]>, so the design was flawed. This has been fixed, so is both a
	86	bug fix and an incompatibility. [perl #133547]
	87
	88	All digits in a run still have to come from the same set of ten digits.
	89
	90	=head1 Modules and Pragmata
	91
	92	=head2 Updated Modules and Pragmata
	93
	94	=over 4
	95
	96	=item *
	97
	98	L<Devel::PPPort> has been upgraded from version 3.44 to 3.45.
	99
	100	=item *
	101
	102	L<Encode> has been upgraded from version 3.00 to 3.01.
	103
	104	=item *
	105
	106	L<ExtUtils::Manifest> has been upgraded from version 1.71 to 1.72.
	107
	108	=item *
	109
	110	L<JSON::PP> has been upgraded from version 4.00 to 4.02.
	111
	112	=item *
	113
	114	L<Module::CoreList> has been upgraded from version 5.20190220 to 5.20190320.
	115
	116	=item *
	117
	118	L<perl5db.pl> has been upgraded from version 1.54 to 1.55.
	119
	120	Debugging threaded code no longer deadlocks in C<DB::sub> nor
	121	C<DB::lsub>.
	122
	123	=item *
124
125	L<PerlIO::encoding> has been upgraded from version 0.26 to 0.27.
126
127	Warnings enabled by setting the C<WARN_ON_ERR> flag in
128	C<$PerlIO::encoding::fallback> are now only produced if warnings are
129	enabled with C<use warnings "utf8";> or setting C<$^W>.
130
131	=item *
132
133	L<threads::shared> has been upgraded from version 1.59 to 1.60.
134
135	Added support for extra tracing of locking, this requires a
136	C<-DDEBUGGING> and extra compilation flags.
137
138	=item *
139
140	L<utf8> has been upgraded from version 1.21 to 1.22.
141
142	=item *
143
144	L<warnings> has been upgraded from version 1.43 to 1.44.
145
455565b9 JK	146	=item *
	147
	148	L<ExtUtils::CBuilder> has been upgraded from version 0.280230 to 0.280231.
	149
ab6f2e91 ZE	150	=back
	151
	152	=head1 Diagnostics
	153
	154	The following additions or changes have been made to diagnostic output,
	155	including warnings and fatal error messages. For the complete list of
	156	diagnostic messages, see L<perldiag>.
	157
	158	=head2 Changes to Existing Diagnostics
	159
	160	=over 4
	161
	162	=item *
	163
	164	Specifying C<\o{}> without anything between the braces now yields the
	165	fatal error message "Empty \o{}". Previously it was "Number with no
	166	digits". This means the same wording is used for this kind of error as
	167	with similar constructs such as C<\p{}>.
	168
	169	=item *
	170
	171	Within the scope of the experimental feature C<use re 'strict'>,
	172	specifying C<\x{}> without anything between the braces now yields the
	173	fatal error message "Empty \x{}". Previously it was "Number with no
	174	digits". This means the same wording is used for this kind of error as
	175	with similar constructs such as C<\p{}>. It is legal, though not wise
	176	to have an empty C<\x> outside of C<re 'strict'>; it silently generates
	177	a NUL character.
	178
	179	=back
	180
	181	=head1 Internal Changes
	182
	183	=over 4
	184
	185	=item *
	186
	187	Added C<newSVsv_nomg()> to copy a SV without processing get magic on
	188	the source. [perl #132964]
	189
	190	=back
	191
	192	=head1 Selected Bug Fixes
	193
	194	=over 4
	195
	196	=item *
	197
	198	C<pack()> no longer can return malformed UTF-8. It croaks if it would
	199	otherwise return a UTF-8 string that contains malformed UTF-8. This
	200	protects agains potential security threats. [perl #131642]
	201
	202	=item *
	203
	204	See L</Any set of digits in the Common script are legal in a script run
	205	of another script>.
	206
	207	=back
	208
	209	=head1 Acknowledgements
	210
	211	Perl 5.29.9 represents approximately 4 weeks of development since Perl
	212	5.29.8 and contains approximately 47,000 lines of changes across 210 files
	213	from 11 authors.
214
215	Excluding auto-generated files, documentation and release tools, there were
216	approximately 38,000 lines of changes to 71 .pm, .t, .c and .h files.
217
218	Perl continues to flourish into its fourth decade thanks to a vibrant
219	community of users and developers. The following people are known to have
220	contributed the improvements that became Perl 5.29.9:
221
222	Chris 'BinGOs' Williams, Craig A. Berry, Dagfinn Ilmari Mannsåker, Dan
223	Kogai, David Mitchell, Karen Etheridge, Karl Williamson, Nicolas R., Pali,
224	Tony Cook, Unicode Consortium.
225
226	The list above is almost certainly incomplete as it is automatically
227	generated from version control history. In particular, it does not include
228	the names of the (very much appreciated) contributors who reported issues to
229	the Perl bug tracker.
230
231	Many of the changes included in this version originated in the CPAN modules
232	included in Perl's core. We're grateful to the entire CPAN community for
233	helping Perl to flourish.
234
235	For a more complete list of all of Perl's historical contributors, please
236	see the F<AUTHORS> file in the Perl source distribution.
237
238	=head1 Reporting Bugs
239
240	If you find what you think is a bug, you might check the perl bug database
241	at L<https://rt.perl.org/>. There may also be information at
242	L<http://www.perl.org/>, the Perl Home Page.
243
244	If you believe you have an unreported bug, please run the L<perlbug> program
245	included with your release. Be sure to trim your bug down to a tiny but
246	sufficient test case. Your bug report, along with the output of C<perl -V>,
247	will be sent off to perlbug@perl.org to be analysed by the Perl porting team.
248
249	If the bug you are reporting has security implications which make it
250	inappropriate to send to a publicly archived mailing list, then see
251	L<perlsec/SECURITY VULNERABILITY CONTACT INFORMATION>
252	for details of how to report the issue.
253
254	=head1 Give Thanks
255
256	If you wish to thank the Perl 5 Porters for the work we had done in Perl 5,
257	you can do so by running the C<perlthanks> program:
258
259	perlthanks
260
261	This will send an email to the Perl 5 Porters list with your show of thanks.
262
263	=head1 SEE ALSO
264
265	The F<Changes> file for an explanation of how to view exhaustive details on
266	what changed.
267
268	The F<INSTALL> file for how to build Perl.
269
270	The F<README> file for general stuff.
271
272	The F<Artistic> and F<Copying> files for copyright information.
273
274	=cut