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perldelta: remove "maybe this won't be in 5.26" note about PERL_USE_UNSAFE_INC
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1=encoding utf8
2
3=head1 NAME
4
2c8edc25 5perldelta - what is new for perl v5.26.0
eabfc7bc 6
2cfe9b50 7=head1 DESCRIPTION
eabfc7bc 8
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9This document describes the differences between the 5.24.0 release and the
105.26.0 release.
11
12=head1 Core Enhancements
f3ed8cbf 13
2c8edc25 14=head2 New regular expression modifier C</xx>
f4b40f11 15
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16Specifying two C<x> characters to modify a regular expression pattern
17does everything that a single one does, but additionally TAB and SPACE
18characters within a bracketed character class are generally ignored and
19can be added to improve readability, like
20S<C</[ ^ A-Z d-f p-x ]/xx>>. Details are at
21L<perlre/E<sol>x and E<sol>xx>.
5e50eae4 22
2c8edc25 23=head2 New Hash Function For 64-bit Builds
a049258c 24
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25We have switched to a hybrid hash function to better balance
26performance for short and long keys.
27
28For short keys, 16 bytes and under, we use an optimised variant of
29One At A Time Hard, and for longer keys we use Siphash 1-3. For very
30long keys this is a big improvement in performance. For shorter keys
31there is a modest improvement.
32
33=head2 Indented Here-documents
34
35This adds a new modifier '~' to here-docs that tells the parser
36that it should look for /^\s*$DELIM\n/ as the closing delimiter.
37
38These syntaxes are all supported:
39
40 <<~EOF;
41 <<~\EOF;
42 <<~'EOF';
43 <<~"EOF";
44 <<~`EOF`;
45 <<~ 'EOF';
46 <<~ "EOF";
47 <<~ `EOF`;
48
49The '~' modifier will strip, from each line in the here-doc, the
50same whitespace that appears before the delimiter.
51
52Newlines will be copied as is, and lines that don't include the
53proper beginning whitespace will cause perl to croak.
54
55For example:
56
57 if (1) {
58 print <<~EOF;
59 Hello there
60 EOF
61 }
62
63prints "Hello there\n" with no leading whitespace.
64
65=head2 '.' and @INC
66
67Perl now provides a way to build perl without C<.> in @INC by default. If you
68want this feature, you can build with -Ddefault_inc_excludes_dot
69
21f25801 70Because the testing / make process for perl modules does not function well with
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71C<.> missing from @INC, Perl now supports the environment variable
72PERL_USE_UNSAFE_INC=1 which makes Perl behave as it previously did, returning
73C<.> to @INC in all child processes.
74
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75=head2 create a safer utf8_hop() called utf8_hop_safe()
76
77Unlike utf8_hop(), utf8_hop_safe() won't navigate before the beginning or after
78the end of the supplied buffer.
79
80=head2 @{^CAPTURE}, %{^CAPTURE}, and %{^CAPTURE_ALL}
81
82C<@{^CAPTURE}> exposes the capture buffers of the last match as an
83array. So C<$1> is C<${^CAPTURE}[0]>.
84
85C<%{^CAPTURE}> is the equivalent to C<%+> (ie named captures)
86
87C<%{^CAPTURE_ALL}> is the equivalent to C<%-> (ie all named captures).
88
89=head2 Unicode 9.0 is now supported
90
91A list of changes is at L<http://www.unicode.org/versions/Unicode9.0.0/>.
92Modules that are shipped with core Perl but not maintained by p5p do not
93necessarily support Unicode 9.0. L<Unicode::Normalize> does work on 9.0.
94
95=head2 Use of C<\p{I<script>}> uses the improved Script_Extensions property
96
97Unicode 6.0 introduced an improved form of the Script (C<sc>) property, and
98called it Script_Extensions (C<scx>). As of now, Perl uses this improved
99version when a property is specified as just C<\p{I<script>}>. The meaning of
100compound forms, like C<\p{sc=I<script>}> are unchanged. This should make
101programs be more accurate when determining if a character is used in a given
102script, but there is a slight chance of breakage for programs that very
103specifically needed the old behavior. See L<perlunicode/Scripts>.
104
105=head2 Declaring a reference to a variable
106
107As an experimental feature, Perl now allows the referencing operator to come
108after L<C<my()>|perlfunc/my>, L<C<state()>|perlfunc/state>,
109L<C<our()>|perlfunc/our>, or L<C<local()>|perlfunc/local>. This syntax must
110be enabled with C<use feature 'declared_refs'>. It is experimental, and will
111warn by default unless C<no warnings 'experimental::refaliasing'> is in effect.
112It is intended mainly for use in assignments to references. For example:
113
114 use experimental 'refaliasing', 'declared_refs';
115 my \$a = \$b;
116
a9fbda47 117See L<perlref/Assigning to References> for more details.
a049258c 118
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119=head2 Perl can now do default collation in UTF-8 locales on platforms
120that support it
a049258c 121
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122Some platforms natively do a reasonable job of collating and sorting in
123UTF-8 locales. Perl now works with those. For portability and full
124control, L<Unicode::Collate> is still recommended, but now you may
125not need to do anything special to get good-enough results, depending on
126your application. See
127L<perllocale/Category C<LC_COLLATE>: Collation: Text Comparisons and Sorting>.
128
129=head2 Better locale collation of strings containing embedded C<NUL>
130characters
131
132In locales that have multi-level character weights, these are now
133ignored at the higher priority ones. There are still some gotchas in
134some strings, though. See
135L<perllocale/Collation of strings containing embedded C<NUL> characters>.
136
137=head2 Lexical subroutines are no longer experimental
138
2586f92e 139Using the C<lexical_subs> feature introduced in v5.18 no longer emits a warning. Existing
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140code that disables the C<experimental::lexical_subs> warning category
141that the feature previously used will continue to work. The
142C<lexical_subs> feature has no effect; all Perl code can use lexical
143subroutines, regardless of what feature declarations are in scope.
144
145=head2 C<CORE> subroutines for hash and array functions callable via
146reference
147
148The hash and array functions in the C<CORE> namespace--C<keys>, C<each>,
149C<values>, C<push>, C<pop>, C<shift>, C<unshift> and C<splice>--, can now
150be called with ampersand syntax (C<&CORE::keys(\%hash>) and via reference
e6abae1c 151(C<< my $k = \&CORE::keys; $k-E<gt>(\%hash) >>). Previously they could only be
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152used when inlined.
153
154=head2 POSIX::tmpnam() has been removed
155
156The fundamentally unsafe C<tmpnam()> interface was deprecated in
157Perl 5.22.0 and has now been removed. In its place you can use
158for example the L<File::Temp> interfaces.
159
160=head2 require ::Foo::Bar is now illegal.
161
162Formerly, C<require ::Foo::Bar> would try to read F</Foo/Bar.pm>. Now any
163bareword require which starts with a double colon dies instead.
164
165=head2 Unescaped literal C<"{"> characters in regular expression
166patterns are no longer permissible
167
168You have to now say something like C<"\{"> or C<"[{]"> to specify to
169match a LEFT CURLY BRACKET. This will allow future extensions to the
170language. This restriction is not enforced, nor are there current plans
171to enforce it, if the C<"{"> is the first character in the pattern.
172
173These have been deprecated since v5.16, with a deprecation message
174displayed starting in v5.22.
175
176=head2 Literal control character variable names are no longer permissible
177
178A variable name may no longer contain a literal control character under
179any circumstances. These previously were allowed in single-character
180names on ASCII platforms, but have been deprecated there since Perl
181v5.20. This affects things like C<$I<\cT>>, where I<\cT> is a literal
182control (such as a C<NAK> or C<NEGATIVE ACKNOWLEDGE> character) in the
183source code.
184
185=head2 C<NBSP> is no longer permissible in C<\N{...}>
186
187The name of a character may no longer contain non-breaking spaces. It
188has been deprecated to do so since Perl v5.22.
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189
190=head1 Security
191
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192=head2 Remove current dir (C<.>) from C<@INC>
193
194For security reasons, C<@INC> no longer contains the default directory
195(C<.>).
196
197=head2 "Escaped" colons and relative paths in PATH
198
199On Unix systems, Perl treats any relative paths in the PATH environment
200variable as tainted when starting a new process. Previously, it was
201allowing a backslash to escape a colon (unlike the OS), consequently
202allowing relative paths to be considered safe if the PATH was set to
203something like C</\:.>. The check has been fixed to treat C<.> as tainted
204in that example.
205
206=head2 C<-Di> switch is now required for PerlIO debugging output
207
208Previously PerlIO debugging output would be sent to the file specified
209by the C<PERLIO_DEBUG> environment variable if perl wasn't running
210setuid and the C<-T> or C<-t> switches hadn't been parsed yet.
211
212If perl performed output at a point where it hadn't yet parsed its
213switches this could result in perl creating or overwriting the file
214named by C<PERLIO_DEBUG> even when the C<-T> switch had been supplied.
215
216Perl now requires the C<-Di> switch to produce PerlIO debugging
217output. By default this is written to C<stderr>, but can optionally
218be redirected to a file by setting the C<PERLIO_DEBUG> environment
219variable.
a049258c 220
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221If perl is running setuid or the C<-T> switch has supplied
222C<PERLIO_DEBUG> is ignored and the debugging output is sent to
223C<stderr> as for any other C<-D> switch.
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224
225=head1 Incompatible Changes
226
2c8edc25 227=head2 C<${^ENCODING}> has been removed
a049258c 228
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229Consequently, the L<encoding> pragma's default mode is no longer supported. If
230you still need to write your source code in encodings other than UTF-8, use a
231source filter such as L<Filter::Encoding> on CPAN or L<encoding>'s C<Filter>
232option.
a049258c 233
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234=head2 C<scalar(%hash)> return signature changed
235
236The value returned for C<scalar(%hash)> will no longer show information about
237the buckets allocated in the hash. It will simply return the count of used
238keys. It is thus equivalent to C<0+keys(%hash)>.
239
240A form of backwards compatibility is provided via C<Hash::Util::bucket_ratio()>
241which provides the same behavior as C<scalar(%hash)> provided prior to Perl
2425.25.
243
244=head2 C<keys> returned from an lvalue subroutine
245
246C<keys> returned from an lvalue subroutine can no longer be assigned
247to in list context.
248
249 sub foo : lvalue { keys(%INC) }
250 (foo) = 3; # death
251 sub bar : lvalue { keys(@_) }
252 (bar) = 3; # also an error
253
254This makes the lvalue sub case consistent with C<(keys %hash) = ...> and
255C<(keys @_) = ...>, which are also errors. [perl #128187]
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256
257=head1 Deprecations
258
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259=head2 String delimiters that aren't stand-alone graphemes are now deprecated
260
261In order for Perl to eventually allow string delimiters to be Unicode
262grapheme clusters (which look like a single character, but may be
263a sequence of several ones), we have to stop allowing a single char
264delimiter that isn't a grapheme by itself. These are unlikely to exist
265in actual code, as they would typically display as attached to the
266character in front of them.
267
268=head1 Performance Enhancements
a049258c 269
2c8edc25 270=over 4
a049258c 271
2c8edc25 272=item *
a049258c 273
2c8edc25 274A hash in boolean context is now sometimes faster, e.g.
a049258c 275
2c8edc25 276 if (!%h) { ... }
a049258c 277
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278This was already special-cased, but some cases were missed, and even the
279ones which weren't have been improved.
a049258c 280
2c8edc25 281=item *
a049258c 282
2c8edc25 283Several other ops may now also be faster in boolean context.
a049258c 284
2c8edc25 285=item * New Faster Hash Function on 64 bit builds
a049258c 286
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287We use a different hash function for short and long keys. This should
288improve performance and security, especially for long keys.
a049258c 289
2c8edc25 290=item * readline is faster
a049258c 291
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292Reading from a file line-by-line with C<readline()> or C<< E<lt>E<gt> >> should
293now typically be faster due to a better implementation of the code that
294searches for the next newline character.
295
296=item *
a049258c 297
2c8edc25 298Reduce cost of SvVALID().
a049258c 299
2c8edc25 300=item *
ad5c8857 301
2c8edc25 302C<$ref1 = $ref2> has been optimized.
5e50eae4 303
4b99a68c 304=item *
f4b40f11 305
2c8edc25 306Array and hash assignment are now faster, e.g.
ec34c8a4 307
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308 (..., @a) = (...);
309 (..., %h) = (...);
f4b40f11 310
2c8edc25 311especially when the RHS is empty.
ec34c8a4 312
2c8edc25 313=item *
a049258c 314
2c8edc25 315Reduce the number of odd special cases for the C<SvSCREAM> flag.
e770df11 316
2c8edc25 317=item *
a049258c 318
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319Avoid sv_catpvn() in do_vop() when unneeded.
320
321=item *
322
323Enhancements in Regex concat COW implementation.
324
325=item *
326
327Speed up C<AV> and C<HV> clearing/undeffing.
328
329=item *
330
331Better optimise array and hash assignment
332
333=item *
334
335Converting a single-digit string to a number is now substantially faster.
336
337=item *
338
339The internal op implementing the C<split> builtin has been simplified and
340sped up. Firstly, it no longer requires a subsidiary internal C<pushre> op
341to do its work. Secondly, code of the form C<my @x = split(...)> is now
342optimised in the same way as C<@x = split(...)>, and is therefore a few
343percent faster.
344
345=item *
346
347The rather slow implementation for the experimental subroutine signatures
348feature has been made much faster; it is now comparable in speed with the
349old-style C<my ($a, $b, @c) = @_>.
7ca0bfc4 350
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351=item *
352
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353Bareword constant strings are now permitted to take part in constant
354folding. They were originally exempted from constant folding in August 1999,
355during the development of Perl 5.6, to ensure that C<use strict "subs">
356would still apply to bareword constants. That has now been accomplished a
357different way, so barewords, like other constants, now gain the performance
358benefits of constant folding.
359
360This also means that void-context warnings on constant expressions of
361barewords now report the folded constant operand, rather than the operation;
362this matches the behaviour for non-bareword constants.
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363
364=back
365
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366=head1 Modules and Pragmata
367
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368=head2 Updated Modules and Pragmata
369
370=over 4
fbe3f407 371
759020c9 372=item *
7ca0bfc4 373
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374L<Archive::Tar> has been upgraded from version 2.04 to 2.24.
375
376=item *
377
378L<arybase> has been upgraded from version 0.11 to 0.12.
379
380=item *
381
382L<attributes> has been upgraded from version 0.27 to 0.29.
a049258c 383
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384The deprecation message for the C<:unique> and C<:locked> attributes
385now mention they will disappear in Perl 5.28.
a049258c 386
2c8edc25 387=item *
a049258c 388
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389L<B> has been upgraded from version 1.62 to 1.68.
390
391=item *
392
393L<B::Concise> has been upgraded from version 0.996 to 0.999.
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394
395Its output is now more descriptive for C<op_private> flags.
d5c7a4fc 396
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397=item *
398
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399L<B::Debug> has been upgraded from version 1.23 to 1.24.
400
401=item *
402
403L<B::Deparse> has been upgraded from version 1.37 to 1.40.
404
405=item *
406
2c8edc25 407L<B::Xref> has been upgraded from version 1.05 to 1.06.
a049258c 408
2c8edc25 409It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
a049258c 410
2c8edc25 411=item *
a049258c 412
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413L<base> has been upgraded from version 2.23 to 2.25.
414
415=item *
416
417L<bignum> has been upgraded from version 0.42 to 0.47.
418
419=item *
420
421L<Carp> has been upgraded from version 1.40 to 1.42.
422
423=item *
424
425L<charnames> has been upgraded from version 1.43 to 1.44.
426
427=item *
428
429L<Compress::Raw::Bzip2> has been upgraded from version 2.069 to 2.074.
430
431=item *
432
433L<Compress::Raw::Zlib> has been upgraded from version 2.069 to 2.074.
434
435=item *
436
437L<Config::Perl::V> has been upgraded from version 0.25 to 0.28.
438
439=item *
440
441L<CPAN> has been upgraded from version 2.11 to 2.18.
442
443=item *
444
445L<CPAN::Meta> has been upgraded from version 2.150005 to 2.150010.
446
447=item *
448
449L<Data::Dumper> has been upgraded from version 2.160 to 2.167.
a049258c 450
2c8edc25 451The XS implementation now supports Deparse.
a049258c 452
2c8edc25 453This fixes a stack management bug. [perl #130487].
a049258c 454
2c8edc25 455=item *
a049258c 456
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457L<DB_File> has been upgraded from version 1.835 to 1.840.
458
459=item *
460
461L<Devel::Peek> has been upgraded from version 1.23 to 1.26.
462
463=item *
464
465L<Devel::PPPort> has been upgraded from version 3.32 to 3.35.
466
467=item *
468
2c8edc25 469L<Devel::SelfStubber> has been upgraded from version 1.05 to 1.06.
a049258c 470
2c8edc25 471It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
a049258c 472
2c8edc25 473=item *
a049258c 474
0cc8c746 475L<diagnostics> has been upgraded from version 1.34 to 1.36.
a049258c 476
2c8edc25 477It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
7ca0bfc4 478
ad5c8857 479=item *
7ca0bfc4 480
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481L<Digest> has been upgraded from version 1.17 to 1.17_01.
482
483=item *
484
485L<Digest::MD5> has been upgraded from version 2.54 to 2.55.
486
487=item *
488
489L<Digest::SHA> has been upgraded from version 5.95 to 5.96.
490
491=item *
492
493L<DynaLoader> has been upgraded from version 1.38 to 1.42.
494
495=item *
496
497L<Encode> has been upgraded from version 2.80 to 2.88.
498
499=item *
500
501L<encoding> has been upgraded from version 2.17 to 2.19.
8f7edc68 502
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503This module's default mode is no longer supported as of Perl 5.25.3. It now
504dies when imported, unless the C<Filter> option is being used.
d5c7a4fc 505
2c8edc25 506=item *
d5c7a4fc 507
2c8edc25 508L<encoding::warnings> has been upgraded from version 0.12 to 0.13.
a049258c 509
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510This module is no longer supported as of Perl 5.25.3. It emits a warning to
511that effect and then does nothing.
a049258c 512
2c8edc25 513=item *
d5c7a4fc 514
0cc8c746 515L<Errno> has been upgraded from version 1.25 to 1.28.
a049258c 516
2c8edc25 517Document that using C<%!> loads Errno for you.
d5c7a4fc 518
2c8edc25 519It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
3abe9611 520
c714fb1f 521=item *
3ce6a296 522
2c8edc25 523L<ExtUtils::Embed> has been upgraded from version 1.33 to 1.34.
a049258c 524
2c8edc25 525It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
a049258c 526
2c8edc25 527=item *
a049258c 528
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529L<ExtUtils::MakeMaker> has been upgraded from version 7.10_01 to 7.24.
530
531=item *
532
533L<ExtUtils::Miniperl> has been upgraded from version 1.05 to 1.06.
534
535=item *
536
537L<ExtUtils::ParseXS> has been upgraded from version 3.31 to 3.34.
538
539=item *
540
541L<ExtUtils::Typemaps> has been upgraded from version 3.31 to 3.34.
542
543=item *
544
545L<feature> has been upgraded from version 1.42 to 1.47.
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546
547Fixes the Unicode Bug in the range operator.
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548
549=item *
5c92a635 550
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551L<File::Copy> has been upgraded from version 2.31 to 2.32.
552
553=item *
554
555L<File::Fetch> has been upgraded from version 0.48 to 0.52.
556
557=item *
558
559L<File::Glob> has been upgraded from version 1.26 to 1.28.
d5c7a4fc 560
2c8edc25 561Issue a deprecation message for C<File::Glob::glob()>.
d5c7a4fc 562
2c8edc25 563=item *
d5c7a4fc 564
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565L<File::Spec> has been upgraded from version 3.63 to 3.67.
566
567=item *
568
569L<FileHandle> has been upgraded from version 2.02 to 2.03.
570
571=item *
572
2c8edc25 573L<Filter::Simple> has been upgraded from version 0.92 to 0.93.
a049258c 574
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575It no longer treats C<no MyFilter> immediately following C<use MyFilter> as
576end-of-file. [perl #107726]
64afbd29
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577
578=item *
579
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580L<Getopt::Long> has been upgraded from version 2.48 to 2.49.
581
582=item *
583
584L<Getopt::Std> has been upgraded from version 1.11 to 1.12.
585
586=item *
587
588L<Hash::Util> has been upgraded from version 0.19 to 0.22.
589
590=item *
591
592L<HTTP::Tiny> has been upgraded from version 0.056 to 0.070.
a049258c 593
2c8edc25 594Internal 599-series errors now include the redirect history.
a049258c 595
2c8edc25 596=item *
a049258c 597
0cc8c746 598L<I18N::LangTags> has been upgraded from version 0.40 to 0.42.
a049258c 599
2c8edc25 600It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
a049258c 601
2c8edc25 602=item *
a049258c 603
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604L<IO> has been upgraded from version 1.36 to 1.38.
605
606=item *
607
601d9a87 608IO-Compress has been upgraded from version 2.069 to 2.074.
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609
610=item *
611
612L<IO::Socket::IP> has been upgraded from version 0.37 to 0.38.
613
614=item *
615
616L<IPC::Cmd> has been upgraded from version 0.92 to 0.96.
617
618=item *
619
620L<IPC::SysV> has been upgraded from version 2.06_01 to 2.07.
621
622=item *
623
624L<JSON::PP> has been upgraded from version 2.27300 to 2.27400_02.
625
626=item *
627
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628L<lib> has been upgraded from version 0.63 to 0.64.
629
630It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
faab9793 631
c714fb1f 632=item *
ad5c8857 633
0cc8c746
S
634L<List::Util> has been upgraded from version 1.42_02 to 1.46_02.
635
636=item *
637
638L<Locale::Codes> has been upgraded from version 3.37 to 3.42.
639
640=item *
641
642L<Locale::Maketext> has been upgraded from version 1.26 to 1.28.
643
644=item *
645
646L<Locale::Maketext::Simple> has been upgraded from version 0.21 to 0.21_01.
647
648=item *
649
650L<Math::BigInt> has been upgraded from version 1.999715 to 1.999806.
ad5c8857 651
2c8edc25 652There have also been some core customizations.
ad5c8857 653
2c8edc25 654=item *
2e0dcc12 655
0cc8c746
S
656L<Math::BigInt::FastCalc> has been upgraded from version 0.40 to 0.5005.
657
658=item *
659
660L<Math::BigRat> has been upgraded from version 0.260802 to 0.2611.
661
662=item *
663
664L<Math::Complex> has been upgraded from version 1.59 to 1.5901.
665
666=item *
667
668L<Memoize> has been upgraded from version 1.03 to 1.03_01.
669
670=item *
671
672L<Module::CoreList> has been upgraded from version 5.20170420 to 5.20170520.
673
674=item *
675
676L<Module::Load::Conditional> has been upgraded from version 0.64 to 0.68.
677
678=item *
679
680L<Module::Metadata> has been upgraded from version 1.000031 to 1.000033.
681
682=item *
683
684L<mro> has been upgraded from version 1.18 to 1.20.
685
686=item *
687
688L<Net::Ping> has been upgraded from version 2.43 to 2.55.
d5c7a4fc 689
2c8edc25
S
690IPv6 addresses and C<AF_INET6> sockets are now supported, along with several
691other enhancements.
d5c7a4fc 692
2c8edc25
S
693Remove sudo from 500_ping_icmp.t.
694
695Avoid stderr noise in tests
696
697Check for echo in new Net::Ping tests.
d5c7a4fc 698
a049258c 699=item *
d5c7a4fc 700
0cc8c746
S
701L<NEXT> has been upgraded from version 0.65 to 0.67.
702
703=item *
704
705L<Opcode> has been upgraded from version 1.34 to 1.39.
706
707=item *
708
709L<open> has been upgraded from version 1.10 to 1.11.
710
711=item *
712
2c8edc25 713L<OS2::Process> has been upgraded from version 1.11 to 1.12.
a049258c 714
2c8edc25 715It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
a049258c 716
2c8edc25 717=item *
a049258c 718
2c8edc25 719L<overload> has been upgraded from version 1.26 to 1.28.
a049258c 720
2c8edc25 721Its compilation speed has been improved slightly.
a049258c 722
2c8edc25
S
723=item *
724
0cc8c746
S
725L<parent> has been upgraded from version 0.234 to 0.236.
726
727=item *
728
2c8edc25
S
729L<perl5db.pl> has been upgraded from version 1.50 to 1.51.
730
731Ignore F</dev/tty> on non-Unix systems. [perl #113960]
732
733=item *
734
0cc8c746
S
735L<Perl::OSType> has been upgraded from version 1.009 to 1.010.
736
737=item *
738
739L<perlfaq> has been upgraded from version 5.021010 to 5.021011.
740
741=item *
742
743L<PerlIO> has been upgraded from version 1.09 to 1.10.
744
745=item *
746
747L<PerlIO::encoding> has been upgraded from version 0.24 to 0.25.
748
749=item *
750
751L<PerlIO::scalar> has been upgraded from version 0.24 to 0.26.
752
753=item *
754
755L<Pod::Checker> has been upgraded from version 1.60 to 1.73.
756
757=item *
758
759L<Pod::Functions> has been upgraded from version 1.10 to 1.11.
760
761=item *
762
763L<Pod::Html> has been upgraded from version 1.22 to 1.2202.
764
765=item *
766
767L<Pod::Perldoc> has been upgraded from version 3.25_02 to 3.28.
768
769=item *
770
771L<Pod::Simple> has been upgraded from version 3.32 to 3.35.
772
773=item *
774
775L<Pod::Usage> has been upgraded from version 1.68 to 1.69.
776
777=item *
778
779L<POSIX> has been upgraded from version 1.65 to 1.76. This remedies several
2c8edc25
S
780defects in making its symbols exportable. [perl #127821]
781The C<POSIX::tmpnam()> interface has been removed,
782see L</"POSIX::tmpnam() has been removed">.
783Trying to import POSIX subs that have no real implementations
784(like C<POSIX::atend()>) now fails at import time, instead of
785waiting until runtime.
786
787=item *
788
0cc8c746 789L<re> has been upgraded from version 0.32 to 0.34
2c8edc25
S
790
791This adds support for the new L<C<E<47>xx>|perlre/E<sol>x and E<sol>xx>
792regular expression pattern modifier, and a change to the L<S<C<use re
793'strict'>>|re/'strict' mode> experimental feature. When S<C<re
794'strict'>> is enabled, a warning now will be generated for all
795unescaped uses of the two characters C<}> and C<]> in regular
796expression patterns (outside bracketed character classes) that are taken
797literally. This brings them more in line with the C<)> character which
798is always a metacharacter unless escaped. Being a metacharacter only
799sometimes, depending on action at a distance, can lead to silently
800having the pattern mean something quite different than was intended,
801which the S<C<re 'strict'>> mode is intended to minimize.
802
803=item *
804
0cc8c746
S
805L<Safe> has been upgraded from version 2.39 to 2.40.
806
807=item *
808
809L<Scalar::Util> has been upgraded from version 1.42_02 to 1.46_02.
810
811=item *
812
813L<Storable> has been upgraded from version 2.56 to 2.62.
2c8edc25
S
814
815Fixes [perl #130098].
816
817=item *
818
0cc8c746
S
819L<Symbol> has been upgraded from version 1.07 to 1.08.
820
821=item *
822
823L<Sys::Syslog> has been upgraded from version 0.33 to 0.35.
824
825=item *
826
827L<Term::ANSIColor> has been upgraded from version 4.04 to 4.06.
828
829=item *
830
2c8edc25
S
831L<Term::ReadLine> has been upgraded from version 1.15 to 1.16.
832
833It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
834
835=item *
836
0cc8c746 837L<Test> has been upgraded from version 1.28 to 1.30.
2c8edc25
S
838
839It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
840
841=item *
842
0cc8c746
S
843L<Test::Harness> has been upgraded from version 3.36 to 3.38.
844
845=item *
846
847L<Test::Simple> has been upgraded from version 1.001014 to 1.302073.
848
849=item *
850
851L<Thread::Queue> has been upgraded from version 3.09 to 3.12.
852
853=item *
854
2c8edc25
S
855L<Thread::Semaphore> has been upgraded from 2.12 to 2.13.
856
857Added the C<down_timed> method.
858
859=item *
860
0cc8c746 861L<threads> has been upgraded from version 2.07 to 2.15.
2c8edc25
S
862
863Compatibility with 5.8 has been restored.
864
865Fixes [perl #130469].
866
867=item *
868
0cc8c746 869L<threads::shared> has been upgraded from version 1.51 to 1.56.
2c8edc25
S
870
871This fixes [cpan #119529], [perl #130457]
872
873=item *
874
0cc8c746
S
875L<Tie::Hash::NamedCapture> has been upgraded from version 0.09 to 0.10.
876
877=item *
878
879L<Time::HiRes> has been upgraded from version 1.9733 to 1.9741.
2c8edc25
S
880
881It now builds on systems with C++11 compilers (such as G++ 6 and Clang++
8823.9).
883
884Now uses C<clockid_t>.
885
886=item *
887
0cc8c746
S
888L<Time::Local> has been upgraded from version 1.2300 to 1.25.
889
890=item *
891
892L<Unicode::Collate> has been upgraded from version 1.14 to 1.19.
893
894=item *
895
896L<Unicode::UCD> has been upgraded from version 0.64 to 0.68.
2c8edc25
S
897
898It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
899
900=item *
901
0cc8c746
S
902L<version> has been upgraded from version 0.9916 to 0.9917.
903
904=item *
905
906L<VMS::DCLsym> has been upgraded from version 1.06 to 1.08.
2c8edc25
S
907
908It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
a049258c
S
909
910=item *
911
0cc8c746
S
912L<warnings> has been upgraded from version 1.36 to 1.37.
913
914=item *
915
916L<XS::Typemap> has been upgraded from version 0.14 to 0.15.
917
918=item *
919
920L<XSLoader> has been upgraded from version 0.21 to 0.27.
2c8edc25
S
921
922Fixed a security hole in which binary files could be loaded from a path
923outside of L<C<@INC>|perlvar/@INC>.
924
925It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
a049258c
S
926
927=back
928
2c8edc25
S
929=head1 Documentation
930
931=head2 New Documentation
a049258c 932
2c8edc25 933=head3 L<perldeprecation>
a049258c 934
2c8edc25
S
935This file documents all upcoming deprecations, and some of the deprecations
936which already have been removed. The purpose of this documentation is
937two-fold: document what will disappear, and by which version, and serve
938as a guide for people dealing with code which has features that no longer
939work after an upgrade of their perl.
a049258c 940
2c8edc25 941=head2 Changes to Existing Documentation
a049258c 942
2c8edc25 943=head3 L<perlcall>
a049258c
S
944
945=over 4
946
2c8edc25
S
947=item *
948
949Use of unassigned code point or non-standalone grapheme for a delimiter will be a fatal error starting in Perl 5.30
a049258c 950
2c8edc25
S
951This was changed to drop a leading C<v> in C<v5.30>, so it uses the same
952style as other deprecation messages.
a049258c 953
2c8edc25
S
954=item *
955
956"\c%c" is more clearly written simply as "%s".
957
958It was decided to undeprecate the use of C<\c%c>, see L<http://www.nntp.perl.org/group/perl.perl5.porters/2017/02/msg242944.html>
959
960=item *
961
962Removed redundant C<dSP> from an example.
a049258c 963
2c8edc25 964=back
a049258c 965
2c8edc25 966=head3 L<perlcommunity>
a049258c
S
967
968=over 4
969
2c8edc25 970=item *
a049258c 971
2c8edc25 972All references to Usenet have been removed.
a049258c
S
973
974=back
975
2c8edc25
S
976=head3 L<perldata>
977
978=over 4
979
980=item *
981
982Updated documentation of C<scalar(%hash)>. See L</scalar(%hash) return
983signature changed> above.
984
985=item *
a049258c 986
2c8edc25
S
987Use of single character variables, with the variable name a non printable
988character in the range C<\x80>-C<\xFF> is no longer allowed. Update the docs to
989reflect this.
990
991=back
992
993=head3 L<perldelta>
a049258c
S
994
995=over 4
996
2c8edc25 997=item *
a049258c 998
2c8edc25 999All references to Usenet have been removed.
a049258c
S
1000
1001=back
1002
2c8edc25
S
1003=head3 L<perldiag>
1004
1005=over 4
1006
1007=item *
1008
1009Deprecations are to be marked with a D.
1010C<"%s() is deprecated on :utf8 handles"> use a deprecation message, and as
1011such, such be marked C<"(D deprecated)"> and not C<"(W deprecated)">.
a049258c 1012
2c8edc25 1013=back
a049258c 1014
2c8edc25 1015=head3 L<perlexperiment>
a049258c
S
1016
1017=over 4
1018
1019=item *
1020
2c8edc25 1021Documented new feature: See L</Declaring a reference to a variable> above.
a049258c
S
1022
1023=back
1024
2c8edc25
S
1025=head3 L<perlfunc>
1026
1027=over 4
1028
1029=item *
1030
1031Defined on aggregates is no longer allowed. Perlfunc was still reporting it as
1032deprecated, and that it will be deleted in the future.
1033
1034=item *
1035
1036Clarified documentation of L<C<seek()>|perlfunc/seek>,
1037L<C<tell()>|perlfunc/tell> and L<C<sysseek()>|perlfunc/sysseek>.
1038L<[perl #128607]|https://rt.perl.org/Public/Bug/Display.html?id=128607>
a049258c 1039
2c8edc25
S
1040=item *
1041
1042Removed obsolete documentation of L<C<study()>|perlfunc/study>.
1043
1044=back
a049258c 1045
2c8edc25 1046=head3 L<perlguts>
a049258c
S
1047
1048=over 4
1049
1050=item *
1051
2c8edc25 1052Add C<pTHX_> to magic method examples.
a049258c
S
1053
1054=back
1055
2c8edc25
S
1056=head3 L<perlhack>
1057
1058=over 4
1059
1060=item *
1061
1062Document Tab VS Space.
a049258c 1063
2c8edc25 1064=back
a049258c 1065
2c8edc25 1066=head3 L<perlinterp>
a049258c
S
1067
1068=over 4
1069
1070=item *
1071
2c8edc25
S
1072L<perlinterp> has been expanded to give a more detailed example of how to
1073hunt around in the parser for how a given operator is handled.
a049258c
S
1074
1075=back
1076
2c8edc25 1077=head3 L<perllocale>
a049258c
S
1078
1079=over 4
1080
1081=item *
1082
2c8edc25
S
1083Document C<NUL> collation handling.
1084
1085=item *
1086
1087Some locales aren't compatible with Perl. Note the potential bad
1088consequences of using them.
a049258c
S
1089
1090=back
1091
2c8edc25
S
1092=head3 L<perlmodinstall>
1093
1094=over 4
1095
1096=item *
1097
1098All references to Usenet have been removed.
1099
1100=back
1101
1102=head3 L<perlmodlib>
1103
1104=over 4
1105
1106=item *
1107
1108Updated the mirror list.
1109
1110=item *
1111
1112All references to Usenet have been removed.
1113
1114=back
1115
1116=head3 L<perlnewmod>
1117
1118=over 4
1119
1120=item *
1121
1122All references to Usenet have been removed.
1123
1124=back
1125
1126=head3 L<perlobj>
1127
1128=over 4
1129
1130=item *
1131
1132Added a section on calling methods using their fully qualified names.
1133
1134=item *
1135
1136Do not discourage manual @ISA.
1137
1138=back
1139
1140=head3 L<perlootut>
1141
1142=over 4
1143
1144=item *
1145
1146Tidy the document.
1147
1148=item *
1149
1150Mention C<Moo> more.
1151
1152=back
1153
1154=head3 L<perlop>
1155
1156=over 4
1157
1158=item *
1159
1160Clarify behavior single quote regexps.
1161
1162=back
1163
1164=head3 L<perlre>
1165
1166=over 4
1167
1168=item *
1169
1170Several minor enhancements to the documentation.
1171
1172=back
1173
1174=head3 L<perlsec>
1175
1176=over 4
1177
1178=item *
1179
1180Fixed link to Crosby paper on hash complexity attack.
1181
1182=back
1183
1184=head3 L<perlref>
1185
1186=over 4
1187
1188=item *
1189
1190Documented new feature: See L</Declaring a reference to a variable> above.
1191
1192=back
1193
1194=head3 L<perltie>
1195
1196=over 4
1197
1198=item *
1199
1200Updated documentation of C<scalar(%hash)>. See L</scalar(%hash) return
1201signature changed> above.
1202
1203=back
1204
1205=head3 L<perlunicode>
1206
1207=over 4
1208
1209=item *
1210
1211Documented change to C<\p{I<script>}> to now use the improved Script_Extensions
1212property. See L</Use of \p{script} uses the improved Script_Extensions
1213property> above.
1214
1215=item *
1216
1217Updated the text to correspond with changes in Unicode UTS#18, concerning
1218regular expressions, and Perl compatibility with what it says.
1219
1220=back
1221
1222=head3 L<perlvar>
1223
1224=over 4
1225
1226=item *
1227
1228Removed obsolete documentation of C<${^ENCODING}>. See L</${^ENCODING} has
1229been removed> above.
1230
1231=item *
1232
1233Document C<@ISA>. Was documented other places, not not in L<perlvar>.
1234
1235=back
1236
1237=head1 Diagnostics
1238
1239=head2 New Diagnostics
1240
1241=head3 New Errors
1242
1243=over 4
1244
1245=item *
1246
1247Since C<.> is now removed from C<@INC> by default, C<do> will now trigger
1248a warning recommending to fix the C<do> statement:
1249
1250L<do "%s" failed, '.' is no longer in @INC|perldiag/do "%s" failed, '.' is no longer in @INC; did you mean do ".E<sol>%s"?>
1251
1252=item *
1253
1254Using the empty pattern (which re-executes the last successfully-matched
1255pattern) inside a code block in another regex, as in C</(?{ s!!new! })/>, has
4f73c567
S
1256always previously yielded a segfault. It now produces an error:
1257L<Infinite recursion in regex|perldiag/"Infinite recursion in regex">.
2c8edc25
S
1258
1259=item *
1260
1261L<The experimental declared_refs feature is not enabled|perldiag/"The experimental declared_refs feature is not enabled">
1262
1263(F) To declare references to variables, as in C<my \%x>, you must first enable
1264the feature:
1265
1266 no warnings "experimental::declared_refs";
1267 use feature "declared_refs";
1268
1269=item *
1270
1271L<Version control conflict marker|perldiag/"Version control conflict marker">
1272
e6abae1c 1273(F) The parser found a line starting with C<E<lt>E<lt>E<lt>E<lt>E<lt>E<lt>E<lt>>,
2c8edc25
S
1274C<E<gt>E<gt>E<gt>E<gt>E<gt>E<gt>E<gt>>, or C<=======>. These may be left by a
1275version control system to mark conflicts after a failed merge operation.
1276
1277=item *
1278
1279L<%s: command not found|perldiag/"%s: command not found">
1280
1281(A) You've accidentally run your script through B<bash> or another shell
1282instead of Perl. Check the #! line, or manually feed your script into
1283Perl yourself. The #! line at the top of your file could look like:
1284
1285 #!/usr/bin/perl
1286
1287=item *
1288
1289L<%s: command not found: %s|perldiag/"%s: command not found: %s">
1290
1291(A) You've accidentally run your script through B<zsh> or another shell
1292instead of Perl. Check the #! line, or manually feed your script into
1293Perl yourself. The #! line at the top of your file could look like:
1294
1295 #!/usr/bin/perl
1296
1297=item *
1298
e6abae1c 1299L<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 mE<sol>%sE<sol>|perldiag/"Unescaped left brace in regex is deprecated here (and will be fatal in Perl 5.30), passed through in regex; marked by S<<-- HERE> in m/%s/">
2c8edc25
S
1300
1301Unescaped left braces are already illegal in some contexts in regular
1302expression patterns, but, due to an oversight, no deprecation warning
1303was raised in other contexts where they are intended to become illegal.
1304This warning is now raised in these contexts.
1305
1306=item *
1307
1308L<Bareword in require contains "%s"|perldiag/"Bareword in require contains "%s"">
1309
1310=item *
1311
1312L<Bareword in require maps to empty filename|perldiag/"Bareword in require maps to empty filename">
1313
1314=item *
1315
1316L<Bareword in require maps to disallowed filename "%s"|perldiag/"Bareword in require maps to disallowed filename "%s"">
1317
1318=item *
1319
1320L<Bareword in require must not start with a double-colon: "%s"|perldiag/"Bareword in require must not start with a double-colon: "%s"">
1321
1322=back
1323
1324=head3 New Warnings
1325
1326=over 4
1327
1328=item *
1329
4f73c567 1330L<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">
2c8edc25
S
1331
1332See L</Deprecations>
1333
1334=item *
1335
1336L<Declaring references is experimental|perldiag/"Declaring references is experimental">
1337
1338(S experimental::declared_refs) This warning is emitted if you use a reference
1339constructor on the right-hand side of C<my()>, C<state()>, C<our()>, or
1340C<local()>. Simply suppress the warning if you want to use the feature, but
1341know that in doing so you are taking the risk of using an experimental feature
1342which may change or be removed in a future Perl version:
1343
1344 no warnings "experimental::declared_refs";
1345 use feature "declared_refs";
1346 $fooref = my \$foo;
1347
1348=item *
1349
4f73c567 1350L<C<${^ENCODING}> is no longer supported. Its use will be fatal in Perl 5.28|perldiag/"${^ENCODING} is no longer supported. Its use will be fatal in Perl 5.28">
2c8edc25
S
1351
1352(D deprecated) The special variable C<${^ENCODING}>, formerly used to implement
1353the C<encoding> pragma, is no longer supported as of Perl 5.26.0.
1354
1355=back
1356
1357=head2 Changes to Existing Diagnostics
1358
1359=over 4
1360
1361=item *
1362
1363When a C<require> fails, we now do not provide C<@INC> when the C<require>
1364is for a file instead of a module.
1365
1366=item *
1367
1368When C<@INC> is not scanned for a C<require> call, we no longer display
1369C<@INC> to avoid confusion.
1370
1371=item *
1372
1373Attribute "locked" is deprecated, and will disappear in Perl 5.28
1374
1375=item *
1376
1377Attribute "unique" is deprecated, and will disappear in Perl 5.28
1378
1379=item *
1380
1381Constants from lexical variables potentially modified elsewhere are
1382deprecated. This will not be allowed in Perl 5.32
1383
1384=item *
1385
1386Deprecated use of my() in false conditional. This will be a fatal error
1387in Perl 5.30
1388
1389=item *
1390
1391dump() better written as CORE::dump(). dump() will no longer be available
1392in Perl 5.30
1393
1394=item *
1395
1396${^ENCODING} is no longer supported. Its use will be fatal in Perl 5.28
1397
1398=item *
1399
1400File::Glob::glob() will disappear in perl 5.30. Use File::Glob::bsd_glob()
1401instead.
1402
1403=item *
1404
1405%s() is deprecated on :utf8 handles. This will be a fatal error in Perl 5.30
1406
1407=item *
1408
1409$* is no longer supported. Its use will be fatal in Perl 5.30
1410
1411=item *
1412
1413$* is no longer supported. Its use will be fatal in Perl 5.30
1414
1415=item *
1416
1417Opening dirhandle %s also as a file. This will be a fatal error in Perl 5.28
1418
1419=item *
1420
1421Opening filehandle %s also as a directory. This will be a fatal
1422error in Perl 5.28
1423
1424=item *
1425
1426Setting $/ to a reference to %s as a form of slurp is deprecated,
1427treating as undef. This will be fatal in Perl 5.28
1428
1429=item *
1430
1431Unescaped left brace in regex is deprecated here (and will be fatal
1432in Perl 5.30), passed through in regex; marked by S<< E<lt>-- HERE >> in m/%s/
1433
1434=item *
1435
1436Unknown charname '' is deprecated. Its use will be fatal in Perl 5.28
1437
1438=item *
1439
1440Use of bare E<lt>E<lt> to mean E<lt>E<lt>"" is deprecated. Its use will be fatal in Perl 5.28
1441
1442=item *
1443
1444Use of code point 0x%s is deprecated; the permissible max is 0x%s.
1445This will be fatal in Perl 5.28
1446
1447=item *
1448
1449Use of comma-less variable list is deprecated. Its use will be fatal
1450in Perl 5.28
1451
1452=item *
1453
1454Use of inherited AUTOLOAD for non-method %s() is deprecated. This
1455will be fatal in Perl 5.28
1456
1457=item *
1458
1459Use of strings with code points over 0xFF as arguments to %s operator
1460is deprecated. This will be a fatal error in Perl 5.28
1461
1462=item *
1463
1464Improve error for missing tie() package/method. This brings the error messages
1465in line with the ones used for normal method calls, despite not using
1466call_method().
1467
1468=item *
1469
1470Make the sysread()/syswrite/() etc :utf8 handle warnings default. These
1471warnings were under 'deprecated' previously.
1472
1473=item *
1474
1475'do' errors now refer to 'do' (not 'require').
1476
1477=item *
1478
1479Details as to the exact problem have been added to the diagnostics that
1480occur when malformed UTF-8 is encountered when trying to convert to a
1481code point.
1482
1483=item *
1484
1485Executing C<undef $x> where C<$x> is tied or magical no longer incorrectly
1486blames the variable for an uninitialized-value warning encountered by the
1487tied/magical code.
1488
1489=item *
1490
e6abae1c 1491L<Unescaped left brace in regex is illegal here in regex; marked by S<E<lt>-- HERE> in mE<sol>%sE<sol>|perldiag/"Unescaped left brace in regex is illegal here in regex; marked by S<<-- HERE> in m/%s/">
2c8edc25
S
1492
1493The word "here" has been added to the message that was raised in
1494v5.25.1. This is to indicate that there are contexts in which unescaped
1495left braces are not (yet) illegal.
1496
1497=item *
1498
1499Code like C<$x = $x . "a"> was incorrectly failing to yield a
1500L<use of uninitialized value|perldiag/"Use of uninitialized value%s">
1501warning when C<$x> was a lexical variable with an undefined value. That has
1502now been fixed. [perl #127877]
1503
1504=item *
1505
1506When the error "Experimental push on scalar is now forbidden" is raised for
1507the hash functions C<keys>, C<each>, and C<values>, it is now followed by
1508the more helpful message, "Type of arg 1 to whatever must be hash or
1509array". [perl #127976]
1510
1511=item *
1512
1513C<undef *_; shift> or C<undef *_; pop> inside a subroutine, with no
1514argument to C<shift> or C<pop>, began crashing in Perl 5.14.0, but has now
1515been fixed.
1516
1517=item *
1518
1519C<< "string$scalar-E<gt>$*" >> now correctly prefers concat overloading to
1520string overloading if C<< $scalar-E<gt>$* >> returns an overloaded object,
1521bringing it into consistency with C<$$scalar>.
1522
1523=item *
1524
1525C<< /@0{0*-E<gt>@*/*0 >> and similar contortions used to crash, but no longer
1526do, but merely produce a syntax error. [perl #128171]
1527
1528=item *
1529
1530C<do> or C<require> with a reference or typeglob which, when stringified,
1531contains a null character started crashing in Perl 5.20.0, but has now been
1532fixed. [perl #128182]
1533
1534=back
1535
1536=head1 Utility Changes
1537
1538=head2 F<c2ph> and F<pstruct>
1539
1540=over 4
1541
1542=item *
1543
1544These old utilities have long since superceded by L<h2xs>, and are
1545now gone from the distribution.
1546
1547=back
1548
1549=head2 F<Porting/pod_lib.pl>
1550
1551=over 4
1552
1553=item *
1554
1555Removed spurious executable bit.
1556
1557=item *
1558
1559Account for possibility of DOS file endings.
1560
1561=back
1562
1563=head2 F<Porting/sync-with-cpan>
1564
1565=over 4
1566
1567=item *
1568
1569Many improvements
1570
1571=back
1572
1573=head2 F<perf/benchmarks>
1574
1575=over 4
1576
1577=item *
1578
1579Tidy file, rename some symbols.
1580
1581=back
1582
1583=head2 F<Porting/checkAUTHORS.pl>
1584
1585=over 4
1586
1587=item *
1588
1589Replace obscure character range with \w.
1590
1591=back
1592
1593=head2 F<t/porting/regen.t>
1594
1595=over 4
1596
1597=item *
1598
1599try to be more helpful when tests fail.
1600
1601=back
1602
1603=head2 F<utils/h2xs.PL>
1604
1605=over 4
1606
1607=item *
1608
1609Avoid infinite loop for enums.
1610
1611=back
1612
1613=head2 L<perlbug>
1614
1615=over 4
1616
1617=item *
1618
1619Long lines in the message body are now wrapped at 900 characters, to stay
1620well within the 1000-character limit imposed by SMTP mail transfer agents.
1621This is particularly likely to be important for the list of arguments to
1622C<Configure>, which can readily exceed the limit if, for example, it names
1623several non-default installation paths. This change also adds the first unit
1624tests for perlbug. [perl #128020]
1625
1626=back
1627
1628=head1 Configuration and Compilation
1629
1630=over 4
1631
1632=item *
1633
1634C<DEFAULT_INC_EXCLUDES_DOT> has been turned on as default.
1635
1636=item *
1637
1638The C<dtrace> build process has further changes:
1639
1640=over
1641
1642=item *
1643
1644If the C<-xnolibs> is available, use that so a F<dtrace> perl can be
1645built within a FreeBSD jail.
1646
1647=item *
1648
1649On systems that build a dtrace object file (FreeBSD, Solaris and
1650SystemTap's dtrace emulation), copy the input objects to a separate
1651directory and process them there, and use those objects in the link,
1652since C<dtrace -G> also modifies these objects.
1653
1654=item *
1655
1656Add libelf to the build on FreeBSD 10.x, since dtrace adds references
1657to libelf symbols.
1658
1659=item *
1660
1661Generate a dummy dtrace_main.o if C<dtrace -G> fails to build it. A
1662default build on Solaris generates probes from the unused inline
1663functions, while they don't on FreeBSD, which causes C<dtrace -G> to
1664fail.
1665
1666=back
1667
1668[perl #130108]
1669
1670=item *
1671
1672You can now disable perl's use of the PERL_HASH_SEED and
1673PERL_PERTURB_KEYS environment variables by configuring perl with
1674C<-Accflags=NO_PERL_HASH_ENV>.
1675
1676=item *
1677
1678You can now disable perl's use of the PERL_HASH_SEED_DEBUG environment
1679variable by configuring perl with
1680C<-Accflags=-DNO_PERL_HASH_SEED_DEBUG>.
1681
1682=item *
1683
1684Zero out the alignment bytes when calculating the bytes for 80-bit C<NaN>
1685and C<Inf> to make builds more reproducible. [perl #130133]
1686
1687=item *
1688
1689Since 5.18 for testing purposes we have included support for
1690building perl with a variety of non-standard, and non-recommended
1691hash functions. Since we do not recommend the use of these functions
1692we have removed them and their corresponding build options. Specifically
1693this includes the following build options:
1694
1695 PERL_HASH_FUNC_SDBM
1696 PERL_HASH_FUNC_DJB2
1697 PERL_HASH_FUNC_SUPERFAST
1698 PERL_HASH_FUNC_MURMUR3
1699 PERL_HASH_FUNC_ONE_AT_A_TIME
1700 PERL_HASH_FUNC_ONE_AT_A_TIME_OLD
1701 PERL_HASH_FUNC_MURMUR_HASH_64A
1702 PERL_HASH_FUNC_MURMUR_HASH_64B
1703
1704=item *
1705
1706Remove "Warning: perl appears in your path"
1707
1708This install warning is more or less obsolete, since most platforms already
1709*will* have a /usr/bin/perl or similar provided by the OS.
1710
1711=item *
1712
1713Reduce verbosity of "make install.man"
1714
1715Previously, two progress messages were emitted for each manpage: one by
1716installman itself, and one by the function in install_lib.pl that it calls to
1717actually install the file. Disabling the second of those in each case saves
1718over 750 lines of unhelpful output.
1719
1720=item *
1721
1722Cleanup for clang -Weverything support. [perl 129961]
1723
1724=item *
1725
1726Configure: signbit scan was assuming too much, stop assuming negative 0.
1727
1728=item *
1729
1730Various compiler warnings have been silenced.
1731
1732=item *
1733
1734Several smaller changes have been made to remove impediments to compiling under
1735C++11.
1736
1737=item *
1738
1739Builds using C<USE_PAD_RESET> now work again; this configuration had
1740bit-rotted.
1741
1742=item *
1743
1744A probe for C<gai_strerror> was added to F<Configure> that checks if the
1745the gai_strerror() routine is available and can be used to
1746translate error codes returned by getaddrinfo() into human
1747readable strings.
1748
1749=item *
1750
1751F<Configure> now aborts if both "-Duselongdouble" and "-Dusequadmath" are
1752requested.
1753L<[perl #126203]|https://rt.perl.org/Public/Bug/Display.html?id=126203>
1754
1755=item *
1756
1757Fixed a bug in which F<Configure> could append "-quadmath" to the archname even
1758if it was already present.
1759L<[perl #128538]|https://rt.perl.org/Public/Bug/Display.html?id=128538>
1760
1761=item *
1762
1763Clang builds with "-DPERL_GLOBAL_STRUCT" or "-DPERL_GLOBAL_STRUCT_PRIVATE" have
1764been fixed (by disabling Thread Safety Analysis for these configurations).
1765
1766=item *
1767
1768F<make_ext.pl> no longer updates a module's F<pm_to_blib> file when no
1769files require updates. This could cause dependencies, F<perlmain.c>
1770in particular, to be rebuilt unnecessarily. [perl #126710]
1771
1772=item *
1773
1774The output of C<perl -V> has been reformatted so that each configuration
1775and compile-time option is now listed one per line, to improve
1776readability.
1777
1778=item *
1779
1780C<Configure> now builds C<miniperl> and C<generate_uudmap> if you
1781invoke it with C<-Dusecrosscompiler> but not C<-Dtargethost=somehost>.
1782This means you can supply your target platform C<config.sh>, generate
1783the headers and proceed to build your cross-target perl. [perl #127234]
1784
1785=item *
1786
1787Builds with C<-Accflags=-DPERL_TRACE_OPS> now only dump the operator
1788counts when the environment variable C<PERL_TRACE_OPS> to be set to a
1789non-zero integer. This allows C<make test> to pass on such a build.
1790
1791=item *
1792
1793When building with GCC 6 and link-time optimization (the C<-flto> option to
1794C<gcc>), C<Configure> was treating all probed symbols as present on the
1795system, regardless of whether they actually exist. This has been fixed.
1796[perl #128131]
1797
1798=item *
1799
1800The F<t/test.pl> library is used for internal testing of Perl itself, and
1801also copied by several CPAN modules. Some of those modules must work on
1802older versions of Perl, so F<t/test.pl> must in turn avoid newer Perl
1803features. Compatibility with Perl 5.8 was inadvertently removed some time
1804ago; it has now been restored. [perl #128052]
1805
1806=item *
1807
1808The build process no longer emits an extra blank line before building each
1809"simple" extension (those with only F<*.pm> and F<*.pod> files).
1810
1811=back
1812
1813=head1 Testing
1814
1815=over 4
1816
1817=item *
1818
1819F<XS-APItest/t/utf8.t>: Several small fixes and enhancements.
1820
1821=item *
1822
1823Tests for locales were erroneously using locales incompatible with Perl.
1824
1825=item *
1826
1827Some parts of the test suite that try to exhaustively test edge cases in the
1828regex implementation have been restricted to running for a maximum of five
1829minutes. On slow systems they could otherwise take several hours, without
1830significantly improving our understanding of the correctness of the code
1831under test.
1832
1833In addition, some of those test cases have been split into more files, to
1834allow them to be run in parallel on suitable systems.
1835
1836=item *
1837
1838A new internal facility allows analysing the time taken by the individual
1839tests in Perl's own test suite; see F<Porting/harness-timer-report.pl>.
1840
1841=item *
1842
1843F<t/re/regexp_nonull.t> has been added to test that the regular expression
1844engine can handle scalars that do not have a null byte just past the end of
1845the string.
1846
1847=item *
1848
1849A new test script, F<t/op/decl-refs.t>, has been added to test the new feature,
1850"Declaring a reference to a variable".
1851
1852=item *
1853
1854A new test script, F<t/re/anyof.t>, has been added to test that the ANYOF nodes
1855generated by bracketed character classes are as expected.
1856
1857=item *
1858
1859F<t/harness> now tries really hard not to run tests outside of the Perl
1860source tree. [perl #124050]
1861
1862=back
1863
1864=head1 Platform Support
1865
1866=head2 New Platforms
1867
1868=over 4
1869
1870=item NetBSD/VAX
1871
1872Perl now compiles under NetBSD on VAX machines. However, it's not
1873possible for that platform to implement floating-point infinities and
1874NaNs compatibly with most modern systems, which implement the IEEE-754
1875floating point standard. The hexadecimal floating point (C<0x...p[+-]n>
1876literals, C<printf %a>) is not implemented, either.
1877The C<make test> passes 98% of tests.
1878
1879=over 4
1880
1881=item *
1882
1883Test fixes and minor updates.
1884
1885=item *
1886
1887Account for lack of C<inf>, C<nan>, and C<-0.0> support.
1888
1889=back
1890
1891=back
1892
1893=head2 Platform-Specific Notes
1894
1895=over 4
1896
1897=item Darwin
1898
1899don't treat -Dprefix=/usr as special, instead require an extra option
1900-Ddarwin_distribution to produce the same results.
1901
1902=item POSIX
1903
1904Finish removing POSIX deprecated functions.
1905
1906=item OS X
1907
1908OS X El Capitan doesn't implement the clock_gettime() or clock_getres() APIs,
1909emulate them as necessary.
1910
1911=item macOS
1912
1913Deprecated syscall(2) on macOS 10.12.
1914
1915=item EBCDIC
1916
1917Several tests have been updated to work (or be skipped) on EBCDIC platforms.
1918
1919=item HP-UX
1920
1921L<Net::Ping> UDP test is skipped on HP-UX.
1922
1923=item Hurd
1924
1925The hints for Hurd have been improved enabling malloc wrap and reporting the
1926GNU libc used (previously it was an empty string when reported).
1927
1928=item VAX
1929
1930VAX floating point formats are now supported.
1931
1932=item VMS
1933
1934=over 4
1935
1936=item *
1937
1938The path separator for the C<PERL5LIB> and C<PERLLIB> environment entries is
1939now a colon (C<:>) when running under a Unix shell. There is no change when
1940running under DCL (it's still C<|>).
1941
1942=item *
1943
1944Remove some VMS-specific hacks from C<showlex.t>. These were added 15 years
1945ago, and are no longer necessary for any VMS version now supported.
1946
1947=item *
1948
1949Move C<_pDEPTH> and C<_aDEPTH> after F<config.h> otherwise DEBUGGING
1950may not be defined yet.
1951
1952=item *
1953
1954VAXC has not been a possibility for a good long while, and the versions of the
1955DEC/Compaq/HP/VSI C compiler that report themselves as "DEC" in a listing file
1956are 15 years or more out-of-date and can be safely desupported.
1957
1958=back
1959
1960=item Windows
1961
1962=over 4
1963
1964=item *
1965
1966Support for compiling perl on Windows using Microsoft Visual Studio 2015
1967(containing Visual C++ 14.0) has been added.
1968
1969This version of VC++ includes a completely rewritten C run-time library, some
1970of the changes in which mean that work done to resolve a socket close() bug in
1971perl #120091 and perl #118059 is not workable in its current state with this
1972version of VC++. Therefore, we have effectively reverted that bug fix for
1973VS2015 onwards on the basis that being able to build with VS2015 onwards is
1974more important than keeping the bug fix. We may revisit this in the future to
1975attempt to fix the bug again in a way that is compatible with VS2015.
1976
1977These changes do not affect compilation with GCC or with Visual Studio versions
1978up to and including VS2013, i.e. the bug fix is retained (unchanged) for those
1979compilers.
1980
1981Note that you may experience compatibility problems if you mix a perl built
1982with GCC or VS E<lt>= VS2013 with XS modules built with VS2015, or if you mix a
1983perl built with VS2015 with XS modules built with GCC or VS E<lt>= VS2013.
1984Some incompatibility may arise because of the bug fix that has been reverted
1985for VS2015 builds of perl, but there may well be incompatibility anyway because
1986of the rewritten CRT in VS2015 (e.g. see discussion at
1987http://stackoverflow.com/questions/30412951).
1988
1989=back
1990
1991=item Win32
1992
1993=over 4
1994
1995=item *
1996
1997Tweaks for Win32 VC vs GCC detection makefile code. This fixes issue that CCHOME
1998depends on CCTYPE, which in auto detect mode is set after CCHOME, so CCHOME uses
1999the uninit CCTYPE var. Also fix else vs .ELSE in makefile.mk
2000
2001=item *
2002
2003fp definitions have been updated.
2004
2005=back
2006
2007=item VMS And Win32
2008
2009Fix some breakage, add 'undef' value for default_inc_excludes_dot in build
2010scripts.
2011
2012=item Linux
2013
2014Drop support for Linux a.out Linux has used ELF for over twenty years.
2015
2016=item OpenBSD 6
2017
2018OpenBSD 6 still does not support returning pid, gid or uid with SA_SIGINFO.
2019Make sure this is accounted for.
2020
2021=item FreeBSD
2022
2023t/uni/overload.t: Skip hanging test on FreeBSD.
2024
2025=back
2026
2027=head1 Internal Changes
2028
2029=over 4
2030
2031=item *
2032
2033The C<op_class()> API function has been added. This is like the existing
2034C<OP_CLASS()> macro, but can more accurately determine what struct an op
2035has been allocated as. For example C<OP_CLASS()> might return
2036C<OA_BASEOP_OR_UNOP> indicating that ops of this type are usually
2037allocated as an C<OP> or C<UNOP>; while C<op_class()> will return
2038C<OPclass_BASEOP> or C<OPclass_UNOP> as appropriate.
2039
2040=item *
2041
2042The output format of the C<op_dump()> function (as used by C<perl -Dx>)
2043has changed: it now displays an "ASCII-art" tree structure, and shows more
2044low-level details about each op, such as its address and class.
2045
2046=item *
2047
2048New versions of macros like C<isALPHA_utf8> and C<toLOWER_utf8> have
2049been added, each with the
2050suffix C<_safe>, like C<isSPACE_utf8_safe>. These take an extra
2051parameter, giving an upper limit of how far into the string it is safe
2052to read. Using the old versions could cause attempts to read beyond the
2053end of the input buffer if the UTF-8 is not well-formed, and their use
2054now raises a deprecation warning. Details are at
2055L<perlapi/Character classification>.
2056
2057=item *
2058
2059Calling macros like C<isALPHA_utf8> on malformed UTF-8 have issued a
2060deprecation warning since Perl v5.18. They now die.
2061Similarly, macros like C<toLOWER_utf8> on malformed UTF-8 now die.
2062
2063=item *
2064
2065Calling the functions C<utf8n_to_uvchr> and its derivatives, while
2066passing a string length of 0 is now asserted against in DEBUGGING
2067builds, and otherwise returns the Unicode REPLACEMENT CHARACTER. If
2068you have nothing to decode, you shouldn't call the decode function.
2069
2070=item *
2071
2072The functions C<utf8n_to_uvchr> and its derivatives now return the
2073Unicode REPLACEMENT CHARACTER if called with UTF-8 that has the overlong
2074malformation, and that malformation is allowed by the input parameters.
2075This malformation is where the UTF-8 looks valid syntactically, but
2076there is a shorter sequence that yields the same code point. This has
2077been forbidden since Unicode version 3.1.
2078
2079=item *
2080
2081The functions C<utf8n_to_uvchr> and its derivatives now accept an input
2082flag to allow the overflow malformation. This malformation is when the
2083UTF-8 may be syntactically valid, but the code point it represents is
2084not capable of being represented in the word length on the platform.
2085What "allowed" means in this case is that the function doesn't return an
2086error, and advances the parse pointer to beyond the UTF-8 in question,
2087but it returns the Unicode REPLACEMENT CHARACTER as the value of the
2088code point (since the real value is not representable).
2089
2090=item *
2091
2092The C<PADOFFSET> type has changed from being unsigned to signed, and
2093several pad-related variables such as C<PL_padix> have changed from being
2094of type C<I32> to type C<PADOFFSET>.
2095
2096=item *
2097
2098The function C<L<perlapi/utf8n_to_uvchr>> has been changed to not
2099abandon searching for other malformations when the first one is
2100encountered. A call to it thus can generate multiple diagnostics,
2101instead of just one.
2102
2103=item *
2104
2105A new function, C<L<perlapi/utf8n_to_uvchr_error>>, has been added for
2106use by modules that need to know the details of UTF-8 malformations
2107beyond pass/fail. Previously, the only ways to know why a sequence was
2108ill-formed was to capture and parse the generated diagnostics, or to do
2109your own analysis.
2110
2111=item *
2112
2113Several new functions for handling Unicode have been added to the API:
2114C<L<perlapi/is_strict_utf8_string>>,
2115C<L<perlapi/is_c9strict_utf8_string>>,
2116C<L<perlapi/is_utf8_string_flags>>,
2117C<L<perlapi/is_strict_utf8_string_loc>>,
2118C<L<perlapi/is_strict_utf8_string_loclen>>,
2119C<L<perlapi/is_c9strict_utf8_string_loc>>,
2120C<L<perlapi/is_c9strict_utf8_string_loclen>>,
2121C<L<perlapi/is_utf8_string_loc_flags>>,
2122C<L<perlapi/is_utf8_string_loclen_flags>>,
2123C<L<perlapi/is_utf8_fixed_width_buf_flags>>,
2124C<L<perlapi/is_utf8_fixed_width_buf_loc_flags>>,
2125C<L<perlapi/is_utf8_fixed_width_buf_loclen_flags>>.
2126
2127These functions are all extensions of the C<is_utf8_string_*()> functions,
2128that apply various restrictions to the UTF-8 recognized as valid.
2129
2130=item *
2131
2132A new API function C<sv_setvpv_bufsize()> allows simultaneously setting the
2133length and allocated size of the buffer in an C<SV>, growing the buffer if
2134necessary.
2135
2136=item *
2137
2138A new API macro C<SvPVCLEAR()> sets its C<SV> argument to an empty string,
2139like Perl-space C<$x = ''>, but with several optimisations.
2140
2141=item *
2142
2143All parts of the internals now agree that the C<sassign> op is a C<BINOP>;
2144previously it was listed as a C<BASEOP> in F<regen/opcodes>, which meant
2145that several parts of the internals had to be special-cased to accommodate
2146it. This oddity's original motivation was to handle code like C<$x ||= 1>;
2147that is now handled in a simpler way.
2148
2149=item *
2150
2151Several new internal C macros have been added that take a string literal as
2152arguments, alongside existing routines that take the equivalent value as two
2153arguments, a character pointer and a length. The advantage of this is that
2154the length of the string is calculated automatically, rather than having to
2155be done manually. These routines are now used where appropriate across the
2156entire codebase.
2157
2158=item *
2159
2160The code in F<gv.c> that determines whether a variable has a special meaning
2161to Perl has been simplified.
2162
2163=item *
2164
2165The C<DEBUGGING>-mode output for regex compilation and execution has been
2166enhanced.
2167
2168=item *
2169
2170Several macros and functions have been added to the public API for
2171dealing with Unicode and UTF-8-encoded strings. See
2172L<perlapi/Unicode Support>.
2173
2174=item *
2175
2176Use C<my_strlcat()> in C<locale.c>. While C<strcat()> is safe in this context,
2177some compilers were optimizing this to C<strcpy()> causing a porting test to
2178fail that looks for unsafe code. Rather than fighting this, we just use
2179C<my_strlcat()> instead.
2180
2181=item *
2182
2183Three new ops, C<OP_ARGELEM>, C<OP_ARGDEFELEM> and C<OP_ARGCHECK> have
2184been added. These are intended principally to implement the individual
2185elements of a subroutine signature, plus any overall checking required.
2186
2187=item *
2188
2189Perl no longer panics when switching into some locales on machines with
2190buggy C<strxfrm()> implementations in their libc. [perl #121734]
2191
2192=item *
2193
2194Perl is now built with the C<PERL_OP_PARENT> compiler define enabled by
2195default. To disable it, use the C<PERL_NO_OP_PARENT> compiler define.
2196This flag alters how the C<op_sibling> field is used in C<OP> structures,
2197and has been available optionally since perl 5.22.0.
2198
2199See L<perl5220delta/"Internal Changes"> for more details of what this
2200build option does.
2201
2202=item *
2203
2204The meanings of some internal SV flags have been changed
2205
2206OPpRUNTIME, SVpbm_VALID, SVpbm_TAIL, SvTAIL_on, SvTAIL_off, SVrepl_EVAL,
2207SvEVALED
2208
2209=item *
2210
2211Change C<hv_fetch(…, "…", …, …)> to C<hv_fetchs(…, "…", …)>
2212
2213The dual-life dists all use Devel::PPPort, so they can use this function even
2214though it was only added in 5.10.
2215
2216=back
2217
2218=head1 Selected Bug Fixes
2219
2220=over 4
2221
2222=item *
2223
2224C< $-{$name} > would leak an C<AV> on each access if the regular
2225expression had no named captures. The same applies to access to any
2226hash tied with L<Tie::Hash::NamedCapture> and C<< all =E<gt> 1 >>. [perl
2227#130822]
2228
2229=item *
2230
2231Attempting to use the deprecated variable C<$#> as the object in an
2232indirect object method call could cause a heap use after free or
2233buffer overflow. [perl #129274]
2234
2235=item *
2236
2237When checking for an indirect object method call in some rare cases
2238the parser could reallocate the line buffer but then continue to use
2239pointers to the old buffer. [perl #129190]
2240
2241=item *
2242
2243Supplying a glob as the format argument to L<perlfunc/formline> would
2244cause an assertion failure. [perl #130722]
2245
2246=item *
2247
2248Code like C< $value1 =~ qr/.../ ~~ $value2 > would have the match
2249converted into a qr// operator, leaving extra elements on the stack to
2250confuse any surrounding expression. [perl #130705]
2251
2252=item *
2253
2254Since 5.24.0 in some obscure cases, a regex which included code blocks
2255from multiple sources (e.g. via embedded via qr// objects) could end up
2256with the wrong current pad and crash or give weird results. [perl #129881]
2257
2258=item *
2259
2260Occasionally C<local()>s in a code block within a patterns weren't being
2261undone when the pattern matching backtracked over the code block.
2262[perl #126697]
2263
2264=item *
2265
2266Using C<substr()> to modify a magic variable could access freed memory
2267in some cases. [perl #129340]
2268
2269=item *
2270
2271Perl 5.25.9 was fixed so that under C<use utf8>, the entire Perl program
2272is checked that the UTF-8 is wellformed. It turns out that several edge
2273cases were missed, and are now fixed. [perl #126310] was the original
2274ticket.
2275
2276=item *
2277
2278Under C<use utf8>, the entire Perl program is now checked that the UTF-8
2279is wellformed. This resolves [perl #126310].
2280
2281=item *
2282
2283The range operator C<..> on strings now handles its arguments correctly when in
2284the scope of the L<< C<unicode_strings>|feature/"The 'unicode_strings' feature" >>
2285feature. The previous behaviour was sufficiently unexpected that we believe no
2286correct program could have made use of it.
2287
2288=item *
2289
2290The S<split> operator did not ensure enough space was allocated for
2291its return value in scalar context. It could then write a single
2292pointer immediately beyond the end of the memory block allocated for
2293the stack. [perl #130262]
2294
2295=item *
2296
2297Using a large code point with the C<W> pack template character with
2298the current output position aligned at just the right point could
2299cause a write a single zero byte immediately beyond the end of an
2300allocated buffer. [perl #129149]
2301
2302=item *
2303
2304Supplying the form picture argument as part of the form argument list
2305where the picture specifies modifying the argument could cause an
2306access to the new freed compiled form. [perl #129125]
2307
2308=item *
2309
2310Fix a problem with sort's build-in compare, where it would not sort
2311correctly with 64-bit integers, and non-long doubles. [perl #130335]
2312
2313=item *
2314
2315Fix issues with /(?{ ... E<lt>E<lt>EOF })/ that broke Method-Signatures. [perl #130398]
2316
2317=item *
2318
2319Fix a macro which caused syntax error on an EBCDIC build.
2320
2321=item *
2322
2323Prevent tests from getting hung up on 'NonStop' option. [perl #130445]
2324
2325=item *
2326
2327Fixed an assertion failure with C<chop> and C<chomp>, which
2328could be triggered by C<chop(@x =~ tr/1/1/)>. [perl #130198].
2329
2330=item *
2331
2332Fixed a comment skipping error under C</x>; it could stop skipping a
2333byte early, which could be in the middle of a UTF-8 character.
2334[perl #130495].
2335
2336=item *
2337
2338F<perldb> now ignores F</dev/tty> on non-Unix systems. [perl #113960];
2339
2340=item *
2341
2342Fix assertion failure for C<{}-E<gt>$x> when C<$x> isn't defined. [perl #130496].
2343
2344=item *
2345
2346DragonFly BSD now has support for setproctitle(). [perl #130068].
2347
2348=item *
2349
2350Fix an assertion error which could be triggered when lookahead string
2351in patterns exceeded a minimum length. [perl #130522].
2352
2353=item *
2354
2355Only warn once per literal about a misplaced C<_>. [perl #70878].
2356
2357=item *
2358
2359Ensure range-start is set after error in C<tr///>. [perl #129342].
2360
2361=item *
2362
2363Don't read past start of string for unmatched backref; otherwise,
2364we may have heap buffer overflow. [perl #129377].
2365
2366=item *
2367
2368Properly recognize mathematical digit ranges starting at U+1D7E.
2369C<use re 'strict'> is supposed to warn if you use a range whose start
2370and end digit aren't from the same group of 10. It didn't do that
2371for five groups of mathematical digits starting at U+1D7E.
2372
2373=item *
2374
2375A sub containing a "forward" declaration with the same name (e.g.,
2376C<sub c { sub c; }>) could sometimes crash or loop infinitely. [perl
2377#129090]
2378
2379=item *
2380
2381A crash in executing a regex with a floating UTF-8 substring against a
2382target string that also used UTF-8 has been fixed. [perl #129350]
2383
2384=item *
2385
2386Previously, a shebang line like C<#!perl -i u> could be erroneously
2387interpreted as requesting the C<-u> option. This has been fixed. [perl
2388#129336]
2389
2390=item *
2391
2392The regex engine was previously producing incorrect results in some rare
2393situations when backtracking past a trie that matches only one thing; this
2394showed up as capture buffers (C<$1>, C<$2>, etc) erroneously containing data
2395from regex execution paths that weren't actually executed for the final
2396match. [perl #129897]
2397
2398=item *
2399
2400Certain regexes making use of the experimental C<regex_sets> feature could
2401trigger an assertion failure. This has been fixed. [perl #129322]
2402
2403=item *
2404
2405Invalid assignments to a reference constructor (e.g., C<\eval=time>) could
2406sometimes crash in addition to giving a syntax error. [perl #125679]
2407
2408=item *
2409
2410The parser could sometimes crash if a bareword came after C<evalbytes>.
2411[perl #129196]
2412
2413=item *
2414
2415Autoloading via a method call would warn erroneously ("Use of inherited
2416AUTOLOAD for non-method") if there was a stub present in the package into
2417which the invocant had been blessed. The warning is no longer emitted in
2418such circumstances. [perl #47047]
2419
2420=item *
2421
2422A sub containing with a "forward" declaration with the same name (e.g.,
2423C<sub c { sub c; }>) could sometimes crash or loop infinitely. [perl
2424#129090]
2425
2426=item *
2427
2428The use of C<splice> on arrays with nonexistent elements could cause other
2429operators to crash. [perl #129164]
2430
2431=item *
2432
2433Fixed case where C<re_untuit_start> will overshoot the length of a utf8
2434string. [perl #129012]
2435
2436=item *
2437
2438Handle C<CXt_SUBST> better in C<Perl_deb_stack_all>, previously it wasn't
2439checking that the I<current> C<cx> is the right type, and instead was always
2440checking the base C<cx> (effectively a noop). [perl #129029]
2441
2442=item *
2443
2444Fixed two possible use-after-free bugs in C<Perl_yylex>. C<Perl_yylex>
2445maintains up to two pointers into the parser buffer, one of which can
2446become stale under the right conditions. [perl #129069]
2447
2448=item *
2449
2450Fixed a crash with C<s///l> where it thought it was dealing with UTF-8
2451when it wasn't. [perl #129038]
2452
2453=item *
2454
2455Fixed place where regex was not setting the syntax error correctly.
2456[perl #129122]
2457
2458=item *
2459
2460The C<&.> operator (and the C<&> operator, when it treats its arguments as
2461strings) were failing to append a trailing null byte if at least one string
2462was marked as utf8 internally. Many code paths (system calls, regexp
2463compilation) still expect there to be a null byte in the string buffer
2464just past the end of the logical string. An assertion failure was the
2465result. [perl #129287]
2466
2467=item *
2468
2469Check C<pack_sockaddr_un()>'s return value because C<pack_sockaddr_un()>
2470silently truncates the supplied path if it won't fit into the C<sun_path>
2471member of C<sockaddr_un>. This may change in the future, but for now
2472check the path in theC<sockaddr> matches the desired path, and skip if
2473it doesn't. [perl #128095]
2474
2475=item *
2476
2477Make sure C<PL_oldoldbufptr> is preserved in C<scan_heredoc()>. In some
2478cases this is used in building error messages. [perl #128988]
2479
2480=item *
2481
2482Check for null PL_curcop in IN_LC() [perl #129106]
2483
2484=item *
2485
2486Fixed the parser error handling for an 'C<:attr(foo>' that does not have
2487an ending 'C<)>'.
2488
2489=item *
2490
2491Fix C<Perl_delimcpy()> to handle a backslash as last char, this
2492actually fixed two bugs, [perl #129064] and [perl #129176].
2493
2494=item *
2495
2496[perl #129267] rework gv_fetchmethod_pvn_flags separator parsing to
2497prevent possible string overrun with invalid len in gv.c
2498
2499=item *
2500
2501Problems with in-place array sorts: code like C<@a = sort { ... } @a>,
2502where the source and destination of the sort are the same plain array, are
2503optimised to do less copying around. Two side-effects of this optimisation
2504were that the contents of C<@a> as visible to to sort routine were
2505partially sorted, and under some circumstances accessing C<@a> during the
2506sort could crash the interpreter. Both these issues have been fixed, and
2507Sort functions see the original value of C<@a>.
2508
2509=item *
2510
2511Non-ASCII string delimiters are now reported correctly in error messages
2512for unterminated strings. [perl #128701]
2513
2514=item *
2515
2516C<pack("p", ...)> used to emit its warning ("Attempt to pack pointer to
2517temporary value") erroneously in some cases, but has been fixed.
2518
2519=item *
2520
2521C<@DB::args> is now exempt from "used once" warnings. The warnings only
2522occurred under B<-w>, because F<warnings.pm> itself uses C<@DB::args>
2523multiple times.
2524
2525=item *
2526
2527The use of built-in arrays or hash slices in a double-quoted string no
2528longer issues a warning ("Possible unintended interpolation...") if the
2529variable has not been mentioned before. This affected code like
2530C<qq|@DB::args|> and C<qq|@SIG{'CHLD', 'HUP'}|>. (The special variables
2531C<@-> and C<@+> were already exempt from the warning.)
2532
2533=item *
2534
2535C<gethostent> and similar functions now perform a null check internally, to
2536avoid crashing with torsocks. This was a regression from 5.22. [perl
2537#128740]
2538
2539=item *
2540
2541C<defined *{'!'}>, C<defined *{'['}>, and C<defined *{'-'}> no longer leak
2542memory if the typeglob in question has never been accessed before.
2543
2544=item *
2545
2546In 5.25.4 fchown() was changed not to accept negative one as an argument
2547because in some platforms that is an error. However, in some other platforms
2548that is an acceptable argument. This change has been reverted [perl #128967].
2549
2550=item *
2551
2552Mentioning the same constant twice in a row (which is a syntax error) no
2553longer fails an assertion under debugging builds. This was a regression
2554from 5.20. [perl #126482]
2555
2556=item *
2557
2558Many issues relating to C<printf "%a"> of hexadecimal floating point
2559were fixed. In addition, the "subnormals" (formerly known as "denormals")
2560floating point anumbers are now supported both with the plain IEEE 754
2561floating point numbers (64-bit or 128-bit) and the x86 80-bit
2562"extended precision". Note that subnormal hexadecimal floating
2563point literals will give a warning about "exponent underflow".
2564[perl #128843, #128889, #128890, #128893, #128909, #128919]
2565
2566=item *
2567
2568A regression in 5.24 with C<tr/\N{U+...}/foo/> when the code point was between
2569128 and 255 has been fixed. [perl #128734].
2570
2571=item *
2572
2573A regression from the previous development release, 5.23.3, where
2574compiling a regular expression could crash the interpreter has been
2575fixed. [perl #128686].
2576
2577=item *
2578
2579Use of a string delimiter whose code point is above 2**31 now works
2580correctly on platforms that allow this. Previously, certain characters,
2581due to truncation, would be confused with other delimiter characters
2582with special meaning (such as C<?> in C<m?...?>), resulting
2583in inconsistent behaviour. Note that this is non-portable,
2584and is based on Perl's extension to UTF-8, and is probably not
2585displayable nor enterable by any editor. [perl #128738]
2586
2587=item *
2588
2589C<@{x> followed by a newline where C<x> represents a control or non-ASCII
2590character no longer produces a garbled syntax error message or a crash.
2591[perl #128951]
2592
2593=item *
2594
2595An assertion failure with C<%: = 0> has been fixed.
2596L<[perl #128238]|https://rt.perl.org/Public/Bug/Display.html?id=128238>
2597
2598=item *
2599
2600In Perl 5.18, the parsing of C<"$foo::$bar"> was accidentally changed, such
2601that it would be treated as C<$foo."::".$bar>. The previous behavior, which
2602was to parse it as C<$foo:: . $bar>, has been restored.
2603L<[perl #128478]|https://rt.perl.org/Public/Bug/Display.html?id=128478>
2604
2605=item *
2606
2607Since Perl 5.20, line numbers have been off by one when perl is invoked with
2608the B<-x> switch. This has been fixed.
2609L<[perl #128508]|https://rt.perl.org/Public/Bug/Display.html?id=128508>
2610
2611=item *
2612
2613Vivifying a subroutine stub in a deleted stash (e.g., C<delete $My::{"Foo::"};
2614\&My::Foo::foo>) no longer crashes. It had begun crashing in Perl 5.18.
2615L<[perl #128532]|https://rt.perl.org/Public/Bug/Display.html?id=128532>
2616
2617=item *
2618
2619Some obscure cases of subroutines and file handles being freed at the same time
2620could result in crashes, but have been fixed. The crash was introduced in Perl
26215.22.
2622L<[perl #128597]|https://rt.perl.org/Public/Bug/Display.html?id=128597>
2623
2624=item *
2625
2626Code that looks for a variable name associated with an uninitialized value
2627could cause an assertion in cases where magic is involved, such as
2628C<$ISA[0][0]>. This has now been fixed.
2629L<[perl #128253]|https://rt.perl.org/Public/Bug/Display.html?id=128253>
2630
2631=item *
2632
2633A crash caused by code generating the warning "Subroutine STASH::NAME
2634redefined" in cases such as C<sub P::f{} undef *P::; *P::f =sub{};> has been
2635fixed. In these cases, where the STASH is missing, the warning will now appear
2636as "Subroutine NAME redefined".
2637L<[perl #128257]|https://rt.perl.org/Public/Bug/Display.html?id=128257>
2638
2639=item *
2640
2641Fixed an assertion triggered by some code that handles deprecated behavior in
2642formats, e.g. in cases like this:
2643
2644 format STDOUT =
2645 @
2646 0"$x"
2647
2648L<[perl #128255]|https://rt.perl.org/Public/Bug/Display.html?id=128255>
2649
2650=item *
2651
2652A possible divide by zero in string transformation code on Windows has been
2653avoided, fixing a crash when collating an empty string.
2654L<[perl #128618]|https://rt.perl.org/Public/Bug/Display.html?id=128618>
2655
2656=item *
2657
2658Some regular expression parsing glitches could lead to assertion failures with
e6abae1c 2659regular expressions such as C</(?E<lt>=/> and C</(?E<lt>!/>. This has now been fixed.
2c8edc25
S
2660L<[perl #128170]|https://rt.perl.org/Public/Bug/Display.html?id=128170>
2661
2662=item *
2663
2664C< until ($x = 1) { ... } > and C< ... until $x = 1 > now properly
2665warn when syntax warnings are enabled. [perl #127333]
2666
2667=item *
2668
2669socket() now leaves the error code returned by the system in C<$!> on
2670failure. [perl #128316]
2671
2672=item *
2673
2674Assignment variants of any bitwise ops under the C<bitwise> feature would
2675crash if the left-hand side was an array or hash. [perl #128204]
2676
2677=item *
2678
2679C<require> followed by a single colon (as in C<foo() ? require : ...> is
2680now parsed correctly as C<require> with implicit $_, rather than
2681C<require "">. [perl #128307]
2682
2683=item *
2684
2685Scalar C<keys %hash> can now be assigned to consistently in all scalar
2686lvalue contexts. Previously it worked for some contexts but not others.
2687
2688=item *
2689
2690List assignment to C<vec> or C<substr> with an array or hash for its first
2691argument used to result in crashes or "Can't coerce" error messages at run
2692time, unlike scalar assignment, which would give an error at compile time.
2693List assignment now gives a compile-time error, too. [perl #128260]
2694
2695=item *
2696
2697Expressions containing an C<&&> or C<||> operator (or their synonyms C<and>
2698and C<or>) were being compiled incorrectly in some cases. If the left-hand
2699side consisted of either a negated bareword constant or a negated C<do {}>
2700block containing a constant expression, and the right-hand side consisted of
2701a negated non-foldable expression, one of the negations was effectively
2702ignored. The same was true of C<if> and C<unless> statement modifiers,
2703though with the left-hand and right-hand sides swapped. This long-standing
2704bug has now been fixed. [perl #127952]
2705
2706=item *
2707
2708C<reset> with an argument no longer crashes when encountering stash entries
2709other than globs. [perl #128106]
2710
2711=item *
2712
2713Assignment of hashes to, and deletion of, typeglobs named C<*::::::> no
2714longer causes crashes. [perl #128086]
2715
2716=item *
2717
2718Handle SvIMMORTALs in LHS of list assign. [perl #129991]
2719
2720=item *
2721
2722[perl #130010] a5540cf breaks texinfo
2723
2724This involved user-defined Unicode properties.
2725
2726=item *
2727
2728Fix error message for unclosed C<\N{> in regcomp.
2729
2730An unclosed C<\N{> could give the wrong error message
2731C<"\N{NAME} must be resolved by the lexer">.
2732
2733=item *
2734
2735List assignment in list context where the LHS contained aggregates and
2736where there were not enough RHS elements, used to skip scalar lvalues.
2737Previously, C<(($a,$b,@c,$d) = (1))> in list context returned C<($a)>; now
2738it returns C<($a,$b,$d)>. C<(($a,$b,$c) = (1))> is unchanged: it still
2739returns C<($a,$b,$c)>. This can be seen in the following:
2740
2741 sub inc { $_++ for @_ }
2742 inc(($a,$b,@c,$d) = (10))
2743
2744Formerly, the values of C<($a,$b,$d)> would be left as C<(11,undef,undef)>;
2745now they are C<(11,1,1)>.
2746
2747=item *
2748
2749[perl 129903]
2750
2751The basic problem is that code like this: /(?{ s!!! })/ can trigger infinite
2752recursion on the C stack (not the normal perl stack) when the last successful
2753pattern in scope is itself. Since the C stack overflows this manifests as an
2754untrappable error/segfault, which then kills perl.
2755
2756We avoid the segfault by simply forbidding the use of the empty pattern when it
2757would resolve to the currently executing pattern.
2758
2759=item *
2760
2761[perl 128997] Avoid reading beyond the end of the line buffer when there's a
2762short UTF-8 character at the end.
2763
2764=item *
2765
2766[perl 129950] fix firstchar bitmap under utf8 with prefix optimisation.
2767
2768=item *
2769
2770[perl 129954] Carp/t/arg_string.t: be liberal in f/p formats.
2771
2772=item *
2773
2774[perl 129928] make do "a\0b" fail silently instead of throwing.
2775
2776=item *
2777
2778[perl 129130] make chdir allocate the stack it needs.
2779
2780=back
2781
2782=head1 Known Problems
2783
2784=over 4
2785
2786=item *
2787
2788Some modules have been broken by the L<context stack rework|/Internal Changes>.
2789These modules were relying on non-guaranteed implementation details in perl.
2790Their maintainers have been informed, and should contact perl5-porters for
2791advice if needed. Below is a subset of these modules:
2792
2793=over 4
2794
2795=item * L<Algorithm::Permute>
2796
2797=item * L<Coro>
2798
2799L<Coro> and perl v5.22.0 were already incompatible due to a change in the perl,
2800and the reworking on the perl context stack creates a further incompatibility.
2801perl5-porters has L<discussed the issue on the mailing
2802list|http://www.nntp.perl.org/group/perl.perl5.porters/2016/05/msg236174.html>.
2803
2804=item * L<Data::Alias>
2805
2806=item * L<RPerl>
2807
2808=item * L<Scope::Upper>
2809
2810=item * L<TryCatch>
2811
2812=back
2813
2814=item *
2815
2816The module L<lexical::underscore> no longer works on perl v5.24.0, because perl
2817no longer has a lexical C<$_>!
2818
2819=item *
2820
2821C<mod_perl> has been patched for compatibility for v5.22.0 and later but no
2822release has been made. The relevant patch (and other changes) can be found in
2823their source code repository, L<mirrored at
2824GitHub|https://github.com/apache/mod_perl/commit/82827132efd3c2e25cc413c85af61bb63375da6e>.
2825
2826=back
2827
2828=head1 Errata From Previous Releases
2829
2830=over 4
2831
2832=item *
2833
2834Parsing bad POSIX charclasses no longer leaks memory. This was fixed in Perl
28355.25.2
2836L<[perl #128313]|https://rt.perl.org/Public/Bug/Display.html?id=128313>
2837
2838=item *
2839
2840Fixed issues with recursive regexes. The behavior was fixed in Perl 5.24.0.
2841L<[perl #126182]|https://rt.perl.org/Public/Bug/Display.html?id=126182>
2842
2843=back
2844
2845=head1 Obituary
2846
2847Jon Portnoy (AVENJ), a prolific Perl author and admired Gentoo community
2848member, has passed away on August 10, 2016. He will be remembered and
2849missed by all those with which he came in contact and enriched with his
2850intellect, wit, and spirit.
2851
2852It is with great sadness we also note Kip Hampton's passing.. Probably
2853best known as the author of the Perl & XML column on XML.com, he was a
2854core contributor to AxKit, an XML server platform that became an Apache
2855Foundation project. He was a frequent speaker in the early days at
2856OSCON, and most recently at YAPC::NA in Madison. He was frequently on
2857irc.perl.org as `ubu`, generally in the #axkit-dahut community, the
2858group responsible for YAPC::NA Asheville in 2011.
a049258c 2859
2c8edc25
S
2860Kip and his constant contributions to the community will be greatly
2861missed.
a049258c
S
2862
2863=head1 Acknowledgements
2e0dcc12 2864
0cc8c746 2865Perl 5.26.0 represents approximately 12 months of development since Perl 5.24.0
c2948ced 2866and contains approximately 370,000 lines of changes across 2,600 files from 86
0cc8c746
S
2867authors.
2868
2869Excluding auto-generated files, documentation and release tools, there were
2870approximately 230,000 lines of changes to 1,800 .pm, .t, .c and .h files.
2871
2872Perl continues to flourish into its third decade thanks to a vibrant community
2873of users and developers. The following people are known to have contributed the
2874improvements that became Perl 5.24.1:
2875
2876Aaron Crane, Abigail, Ævar Arnfjörð Bjarmason, Alex Vandiver, Andreas
2877König, Andreas Voegele, Andrew Fresh, Andy Lester, Aristotle Pagaltzis, Chad
2878Granum, Chase Whitener, Chris 'BinGOs' Williams, Chris Lamb, Christian Hansen,
2879Christian Millour, Colin Newell, Craig A. Berry, Dagfinn Ilmari Mannsåker, Dan
c2948ced
S
2880Collins, Daniel Dragan, Dave Cross, Dave Rolsky, David Golden, David H.
2881Gutteridge, David Mitchell, Dominic Hargreaves, Doug Bell, E. Choroba, Ed Avis,
2882Father Chrysostomos, François Perrad, Hauke D, H.Merijn Brand, Hugo van der
2883Sanden, Ivan Pozdeev, James E Keenan, James Raspass, Jarkko Hietaniemi, Jerry
2884D. Hedden, Jim Cromie, J. Nick Koston, John Lightsey, Karen Etheridge, Karl
2885Williamson, Leon Timmermans, Lukas Mai, Matthew Horsfall, Maxwell Carey, Misty
2886De Meo, Neil Bowers, Nicholas Clark, Nicolas R., Niko Tyni, Pali, Paul
2887Marquess, Peter Avalos, Petr Písař, Pino Toscano, Rafael Garcia-Suarez, Reini
2888Urban, Renee Baecker, Ricardo Signes, Richard Levitte, Rick Delaney, Salvador
2889Fandiño, Samuel Thibault, Sawyer X, Sébastien Aperghis-Tramoni, Sergey
2890Aleynikov, Shlomi Fish, Smylers, Stefan Seifert, Steffen Müller, Stevan
2891Little, Steve Hay, Steven Humphrey, Sullivan Beck, Theo Buehler, Thomas Sibley,
2892Todd Rinaldo, Tomasz Konojacki, Tony Cook, Unicode Consortium, Yaroslav Kuzmin,
2893Yves Orton, Zefram.
0cc8c746
S
2894
2895The list above is almost certainly incomplete as it is automatically generated
2896from version control history. In particular, it does not include the names of
2897the (very much appreciated) contributors who reported issues to the Perl bug
2898tracker.
2899
2900Many of the changes included in this version originated in the CPAN modules
2901included in Perl's core. We're grateful to the entire CPAN community for
2902helping Perl to flourish.
2903
2904For a more complete list of all of Perl's historical contributors, please see
2905the F<AUTHORS> file in the Perl source distribution.
f5b73711 2906
44691e6f
AB
2907=head1 Reporting Bugs
2908
2c8edc25
S
2909If you find what you think is a bug, you might check the articles recently
2910posted to the comp.lang.perl.misc newsgroup and the perl bug database at
2911L<https://rt.perl.org/> . There may also be information at
4b8803f0 2912L<http://www.perl.org/> , the Perl Home Page.
44691e6f 2913
e08634c5
SH
2914If you believe you have an unreported bug, please run the L<perlbug> program
2915included with your release. Be sure to trim your bug down to a tiny but
2916sufficient test case. Your bug report, along with the output of C<perl -V>,
2917will be sent off to perlbug@perl.org to be analysed by the Perl porting team.
44691e6f 2918
87c118b9
DM
2919If the bug you are reporting has security implications which make it
2920inappropriate to send to a publicly archived mailing list, then see
c0ea3294
SH
2921L<perlsec/SECURITY VULNERABILITY CONTACT INFORMATION>
2922for details of how to report the issue.
44691e6f
AB
2923
2924=head1 SEE ALSO
2925
e08634c5
SH
2926The F<Changes> file for an explanation of how to view exhaustive details on
2927what changed.
44691e6f
AB
2928
2929The F<INSTALL> file for how to build Perl.
2930
2931The F<README> file for general stuff.
2932
2933The F<Artistic> and F<Copying> files for copyright information.
2934
2935=cut