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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
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12=head1 Notice
13
14This release includes two updates with widespread effects:
15
16=over 4
17
18=item * C<.> no longer in C<@INC>
19
20The current modules, and for the execution of scripts. See the section
07b4a50c 21L<< Removal of the current directory (C<.>) from C<@INC> >> for the full details.
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22
23=item * C<do> may now warn
24
25C<do> now gives a mandatory warning when it fails to load a file which it
26would have loaded had C<.> been in C<@INC>.
27
28=back
29
2c8edc25 30=head1 Core Enhancements
f3ed8cbf 31
2c8edc25 32=head2 New regular expression modifier C</xx>
f4b40f11 33
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34Specifying two C<x> characters to modify a regular expression pattern
35does everything that a single one does, but additionally TAB and SPACE
36characters within a bracketed character class are generally ignored and
37can be added to improve readability, like
38S<C</[ ^ A-Z d-f p-x ]/xx>>. Details are at
39L<perlre/E<sol>x and E<sol>xx>.
5e50eae4 40
2c8edc25 41=head2 New Hash Function For 64-bit Builds
a049258c 42
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43We have switched to a hybrid hash function to better balance
44performance for short and long keys.
45
46For short keys, 16 bytes and under, we use an optimised variant of
47One At A Time Hard, and for longer keys we use Siphash 1-3. For very
48long keys this is a big improvement in performance. For shorter keys
49there is a modest improvement.
50
51=head2 Indented Here-documents
52
53This adds a new modifier '~' to here-docs that tells the parser
54that it should look for /^\s*$DELIM\n/ as the closing delimiter.
55
56These syntaxes are all supported:
57
58 <<~EOF;
59 <<~\EOF;
60 <<~'EOF';
61 <<~"EOF";
62 <<~`EOF`;
63 <<~ 'EOF';
64 <<~ "EOF";
65 <<~ `EOF`;
66
67The '~' modifier will strip, from each line in the here-doc, the
68same whitespace that appears before the delimiter.
69
70Newlines will be copied as is, and lines that don't include the
71proper beginning whitespace will cause perl to croak.
72
73For example:
74
75 if (1) {
76 print <<~EOF;
77 Hello there
78 EOF
79 }
80
81prints "Hello there\n" with no leading whitespace.
82
83=head2 '.' and @INC
84
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85Since time immemorial Perl has, as a last resort, loaded libraries
86from the current directory. For security reasons this is no longer the
87case, the C<@INC> variable no longer contains C<.> as its last element
88by default.
89
90If you want to disable this behavior at compile-time build perl with
91C<-Udefault_inc_excludes_dot> (C<-Ddefault_inc_excludes_dot> being the
92default now).
93
94If you'd like to add C<.> back to C<@INC> at runtime set
95C<PERL_USE_UNSAFE_INC=1> in the environment before starting
96perl. Setting it to 1 restores C<.> in the C<@INC> when perl otherwise
97lacks it.
98
99Various toolchain modules will set C<PERL_USE_UNSAFE_INC=1>
100themselves. E.g. L<Test::Harness> sets it since loading modules from a
101relative path is a common idiom in test code. If you find that you
102have C<.> in C<@INC> on a perl built with default settings it's likely
103that your code is being invoked by a toolchain module of some sort.
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104=head2 @{^CAPTURE}, %{^CAPTURE}, and %{^CAPTURE_ALL}
105
106C<@{^CAPTURE}> exposes the capture buffers of the last match as an
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107array. So C<$1> is C<${^CAPTURE}[0]>. This is a more efficient equivalent
108to code like C<substr($matched_string,$-[0],$+[0]-$-[0])>, and you don't
109have to keep track of the C<$matched_string> either. This variable has no
110single character equivalent. Note like the other regex magic variables
111the contents of this variable is dynamic, if you wish to store it beyond
112the lifetime of the match you must copy it to another array.
2c8edc25 113
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114C<%{^CAPTURE}> is the equivalent to C<%+> (ie named captures). Other than
115being more self documenting there is no difference between the two forms.
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116
117C<%{^CAPTURE_ALL}> is the equivalent to C<%-> (ie all named captures).
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118Other than being more self documenting there is no difference between the
119two forms.
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120
121=head2 Unicode 9.0 is now supported
122
123A list of changes is at L<http://www.unicode.org/versions/Unicode9.0.0/>.
124Modules that are shipped with core Perl but not maintained by p5p do not
125necessarily support Unicode 9.0. L<Unicode::Normalize> does work on 9.0.
126
127=head2 Use of C<\p{I<script>}> uses the improved Script_Extensions property
128
129Unicode 6.0 introduced an improved form of the Script (C<sc>) property, and
130called it Script_Extensions (C<scx>). As of now, Perl uses this improved
131version when a property is specified as just C<\p{I<script>}>. The meaning of
132compound forms, like C<\p{sc=I<script>}> are unchanged. This should make
133programs be more accurate when determining if a character is used in a given
134script, but there is a slight chance of breakage for programs that very
135specifically needed the old behavior. See L<perlunicode/Scripts>.
136
137=head2 Declaring a reference to a variable
138
139As an experimental feature, Perl now allows the referencing operator to come
140after L<C<my()>|perlfunc/my>, L<C<state()>|perlfunc/state>,
141L<C<our()>|perlfunc/our>, or L<C<local()>|perlfunc/local>. This syntax must
142be enabled with C<use feature 'declared_refs'>. It is experimental, and will
143warn by default unless C<no warnings 'experimental::refaliasing'> is in effect.
144It is intended mainly for use in assignments to references. For example:
145
146 use experimental 'refaliasing', 'declared_refs';
147 my \$a = \$b;
148
a9fbda47 149See L<perlref/Assigning to References> for more details.
a049258c 150
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151=head2 Perl can now do default collation in UTF-8 locales on platforms
152that support it
a049258c 153
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154Some platforms natively do a reasonable job of collating and sorting in
155UTF-8 locales. Perl now works with those. For portability and full
156control, L<Unicode::Collate> is still recommended, but now you may
157not need to do anything special to get good-enough results, depending on
158your application. See
159L<perllocale/Category C<LC_COLLATE>: Collation: Text Comparisons and Sorting>.
160
161=head2 Better locale collation of strings containing embedded C<NUL>
162characters
163
164In locales that have multi-level character weights, these are now
165ignored at the higher priority ones. There are still some gotchas in
166some strings, though. See
167L<perllocale/Collation of strings containing embedded C<NUL> characters>.
168
169=head2 Lexical subroutines are no longer experimental
170
2586f92e 171Using the C<lexical_subs> feature introduced in v5.18 no longer emits a warning. Existing
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172code that disables the C<experimental::lexical_subs> warning category
173that the feature previously used will continue to work. The
174C<lexical_subs> feature has no effect; all Perl code can use lexical
175subroutines, regardless of what feature declarations are in scope.
176
177=head2 C<CORE> subroutines for hash and array functions callable via
178reference
179
180The hash and array functions in the C<CORE> namespace--C<keys>, C<each>,
181C<values>, C<push>, C<pop>, C<shift>, C<unshift> and C<splice>--, can now
182be called with ampersand syntax (C<&CORE::keys(\%hash>) and via reference
e6abae1c 183(C<< my $k = \&CORE::keys; $k-E<gt>(\%hash) >>). Previously they could only be
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184used when inlined.
185
186=head2 POSIX::tmpnam() has been removed
187
188The fundamentally unsafe C<tmpnam()> interface was deprecated in
189Perl 5.22.0 and has now been removed. In its place you can use
190for example the L<File::Temp> interfaces.
191
192=head2 require ::Foo::Bar is now illegal.
193
194Formerly, C<require ::Foo::Bar> would try to read F</Foo/Bar.pm>. Now any
195bareword require which starts with a double colon dies instead.
196
197=head2 Unescaped literal C<"{"> characters in regular expression
198patterns are no longer permissible
199
200You have to now say something like C<"\{"> or C<"[{]"> to specify to
201match a LEFT CURLY BRACKET. This will allow future extensions to the
202language. This restriction is not enforced, nor are there current plans
203to enforce it, if the C<"{"> is the first character in the pattern.
204
205These have been deprecated since v5.16, with a deprecation message
206displayed starting in v5.22.
207
208=head2 Literal control character variable names are no longer permissible
209
210A variable name may no longer contain a literal control character under
211any circumstances. These previously were allowed in single-character
212names on ASCII platforms, but have been deprecated there since Perl
213v5.20. This affects things like C<$I<\cT>>, where I<\cT> is a literal
214control (such as a C<NAK> or C<NEGATIVE ACKNOWLEDGE> character) in the
215source code.
216
217=head2 C<NBSP> is no longer permissible in C<\N{...}>
218
219The name of a character may no longer contain non-breaking spaces. It
220has been deprecated to do so since Perl v5.22.
a049258c 221
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222=head2 create a safer utf8_hop() called utf8_hop_safe()
223
224Unlike utf8_hop(), utf8_hop_safe() won't navigate before the beginning or after
225the end of the supplied buffer.
226
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227=head1 Security
228
89853d76 229=head2 Removal of the current directory (C<.>) from C<@INC>
2c8edc25 230
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231The perl binary includes a default set of paths in C<@INC>. Historically
232it has also included the current directory (C<.>) as the final entry,
233unless run with taint mode enabled (C<perl -T>). While convenient, this has
234security implications: for example, where a script attempts to load an
235optional module when its current directory is untrusted (such as F</tmp>),
236it could load and execute code from under that directory.
237
238Starting with v5.26.0, C<.> is always removed by default, not just under
239tainting. This has major implications for installing modules and executing
240scripts.
241
242The following new features have been added to help ameliorate these
243issues.
244
245=over
246
247=item * C<Configure -Udefault_inc_excludes_dot>
248
249There is a new C<Configure> option, C<default_inc_excludes_dot> (enabled
250by default) which builds a perl executable without C<.>; unsetting this
251option using C<-U> reverts perl to the old behaviour. This may fix your
252path issues but will reintroduce all the security concerns, so don't
253build a perl executable like this unless you're I<really> confident that
254such issues are not a concern in your environment.
255
256=item * C<$PERL_USE_UNSAFE_INC>
257
258There is a new environment variable recognised by the perl interpreter.
259If this variable has the value C<1> when the perl interpreter starts up,
260then C<.> will be automatically appended to C<@INC> (except under tainting).
261
262This allows you restore the old perl interpreter behaviour on a
263case-by-case basis. But note that this intended to be a temporary crutch,
264and this feature will likely be removed in some future perl version.
265It is currently set by the C<cpan> utility and C<Test::Harness> to
266ease installation of CPAN modules which have not been updated handle the
267lack of dot. Once again, don't use this unless you are sure that this
268will not reintroduce any security concerns.
269
270=item * A new mandatory warning issued by C<do>.
271
272While it is well-known that C<use> and C<require> use C<@INC> to search
273for the file to load, many people don't realise that C<do "file"> also
274searches C<@INC> if the file is a relative path. With the removal of C<.>,
275a simple C<do "file.pl"> will fail to read in and execute C<file.pl> from
276the current directory. Since this is commonly expected behaviour, a new
277mandatory warning is now issued whenever C<do> fails to load a file which
278it otherwise would have found if dot had been in C<@INC>.
279
280=back
281
282Here are some things script and module authors may need to do to make
283their software work in the new regime.
284
285=over
286
287=item * Script authors
288
289If the issue is within your own code (rather than within included
290modules), then you have two main options. Firstly, if you are confident
291that your script will only be run within a trusted directory (under which
292you expect to find trusted files and modules), then add C<.> back into the
293path; e.g.:
294
295 BEGIN {
296 my $dir = "/some/trusted/directory";
297 chdir $dir or die "Can't chdir to $dir: $!\n";
298 # safe now
299 push @INC, '.';
300 }
301 use "Foo::Bar"; # may load /some/trusted/directory/Foo/Bar.pm
302 do "config.pl"; # may load /some/trusted/directory/config.pl
303
304On the other hand, if your script is intended to be run from within
305untrusted directories (such as F</tmp>), then your script suddenly failing
306to load files may be indicative of a security issue. You most likely want
307to replace any relative paths with full paths; for example,
308
309 do ".foo_config.pl"
310
311might become
312
313 do "$ENV{HOME}/.foo_config.pl"
314
315If you are absolutely certain that you want your script to load and
316execute a file from the current directory, then use a C<./> prefix; for
317example:
318
319 do "./.foo_config.pl"
320
321=item * Installing and using CPAN modules
322
323If you install a CPAN module using an automatic tool like C<cpan>, then
324this tool will itself set the C<PERL_USE_UNSAFE_INC> environment variable
325while building and testing the module, which may be sufficient to install
326a distribution which hasn't been updated to be dot-aware. If you want to
327install such a module manually, then you'll need to replace the
328traditional invocation:
329
330 perl Makefile.PL && make && make test && make install
331
332with something like
333
334 (export PERL_USE_UNSAFE_INC=1; \
335 perl Makefile.PL && make && make test && make install)
336
337Note that this only helps build and install an unfixed module. It's
338possible for the tests to pass (since they were run under
339C<PERL_USE_UNSAFE_INC=1>), but for the module itself to fail to perform
340correctly in production. In this case you may have to temporarily modify
341your script until such time as fixed version of the module is released.
342For example:
343
344 use Foo::Bar;
345 {
346 local @INC = (@INC, '.');
347 # assuming read_config() needs '.' in @INC
348 $config = Foo::Bar->read_config();
349 }
350
351This is only rarely expected to be necessary. Again, if doing this,
352assess the resultant risks first.
353
354=item * Module Authors
355
356If you maintain a CPAN distribution, it may need updating to run in
357a dotless environment. Although C<cpan> and other such tools will
358currently set the C<PERL_USE_UNSAFE_INC> during module build, this is
359temporary workaround for the set of modules which rely on C<.> being in
360C<@INC> for installation and testing, and this may mask deeper issues. It
361could result in a module which passes tests and installs, but which
362fails at run time.
363
364During build, test and install, it will normally be the case that any perl
365processes will be executing directly within the root directory of the
366untarred distribution, or a known subdirectory of that, such as F<t/>. It
367may well be that F<Makefile.PL> or F<t/foo.t> will attempt to include
368local modules and configuration files using their direct relative
369filenames, which will now fail.
370
371However, as described above, automatic tools like F<cpan> will (for now)
372set the C<PERL_USE_UNSAFE_INC> environment variable, which introduces
373dot during build.
374
375This makes it likely that your existing build and test code will work, but
376this may mask issues with your code which only manifest when used after
377install. It is prudent to try and run your build process with that
378variable explicitly disabled:
379 (export PERL_USE_UNSAFE_INC=0; \
380 perl Makefile.PL && make && make test && make install)
381
382This is more likely to show up any potential problems with your module's
383build process, or even with the module itself. Fixing such issues will
384ensure both that your module can again be installed manually, and that
385it will still build once the C<PERL_USE_UNSAFE_INC> crutch goes away.
386
387When fixing issues in tests due to the removal of dot from C<@INC>,
388reinsertion of dot into C<@INC> should be performed with caution, for this
389too may suppress real errors in your runtime code. You are encouraged
390wherever possible to apply the aforementioned approaches with explicit
391absolute/relative paths, or relocate your needed files into a subdirectory
392and insert that subdirectory into C<@INC> instead.
393
394If your runtime code has problems under the dotless C<@INC>, then the comments
395above on how to fix for script authors will mostly apply here too. Bear in
396mind though that it is considered bad form for a module to globally add dot to
397C<@INC>, since it introduces both a security risk and hides issues of
398accidentally requiring dot in C<@INC>, as explained above.
399
400=back
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401
402=head2 "Escaped" colons and relative paths in PATH
403
404On Unix systems, Perl treats any relative paths in the PATH environment
405variable as tainted when starting a new process. Previously, it was
406allowing a backslash to escape a colon (unlike the OS), consequently
407allowing relative paths to be considered safe if the PATH was set to
408something like C</\:.>. The check has been fixed to treat C<.> as tainted
409in that example.
410
411=head2 C<-Di> switch is now required for PerlIO debugging output
412
413Previously PerlIO debugging output would be sent to the file specified
414by the C<PERLIO_DEBUG> environment variable if perl wasn't running
415setuid and the C<-T> or C<-t> switches hadn't been parsed yet.
416
417If perl performed output at a point where it hadn't yet parsed its
418switches this could result in perl creating or overwriting the file
419named by C<PERLIO_DEBUG> even when the C<-T> switch had been supplied.
420
421Perl now requires the C<-Di> switch to produce PerlIO debugging
422output. By default this is written to C<stderr>, but can optionally
423be redirected to a file by setting the C<PERLIO_DEBUG> environment
424variable.
a049258c 425
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426If perl is running setuid or the C<-T> switch has supplied
427C<PERLIO_DEBUG> is ignored and the debugging output is sent to
428C<stderr> as for any other C<-D> switch.
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429
430=head1 Incompatible Changes
431
2c8edc25 432=head2 C<${^ENCODING}> has been removed
a049258c 433
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434Consequently, the L<encoding> pragma's default mode is no longer supported. If
435you still need to write your source code in encodings other than UTF-8, use a
436source filter such as L<Filter::Encoding> on CPAN or L<encoding>'s C<Filter>
437option.
a049258c 438
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439=head2 C<scalar(%hash)> return signature changed
440
441The value returned for C<scalar(%hash)> will no longer show information about
442the buckets allocated in the hash. It will simply return the count of used
443keys. It is thus equivalent to C<0+keys(%hash)>.
444
445A form of backwards compatibility is provided via C<Hash::Util::bucket_ratio()>
446which provides the same behavior as C<scalar(%hash)> provided prior to Perl
4475.25.
448
449=head2 C<keys> returned from an lvalue subroutine
450
451C<keys> returned from an lvalue subroutine can no longer be assigned
452to in list context.
453
454 sub foo : lvalue { keys(%INC) }
455 (foo) = 3; # death
456 sub bar : lvalue { keys(@_) }
457 (bar) = 3; # also an error
458
459This makes the lvalue sub case consistent with C<(keys %hash) = ...> and
460C<(keys @_) = ...>, which are also errors. [perl #128187]
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461
462=head1 Deprecations
463
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464=head2 String delimiters that aren't stand-alone graphemes are now deprecated
465
466In order for Perl to eventually allow string delimiters to be Unicode
467grapheme clusters (which look like a single character, but may be
468a sequence of several ones), we have to stop allowing a single char
469delimiter that isn't a grapheme by itself. These are unlikely to exist
470in actual code, as they would typically display as attached to the
471character in front of them.
472
473=head1 Performance Enhancements
a049258c 474
2c8edc25 475=over 4
a049258c 476
2c8edc25 477=item *
a049258c 478
2c8edc25 479A hash in boolean context is now sometimes faster, e.g.
a049258c 480
2c8edc25 481 if (!%h) { ... }
a049258c 482
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483This was already special-cased, but some cases were missed, and even the
484ones which weren't have been improved.
a049258c 485
2c8edc25 486=item *
a049258c 487
2c8edc25 488Several other ops may now also be faster in boolean context.
a049258c 489
2c8edc25 490=item * New Faster Hash Function on 64 bit builds
a049258c 491
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492We use a different hash function for short and long keys. This should
493improve performance and security, especially for long keys.
a049258c 494
2c8edc25 495=item * readline is faster
a049258c 496
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497Reading from a file line-by-line with C<readline()> or C<< E<lt>E<gt> >> should
498now typically be faster due to a better implementation of the code that
499searches for the next newline character.
500
501=item *
a049258c 502
2c8edc25 503Reduce cost of SvVALID().
a049258c 504
2c8edc25 505=item *
ad5c8857 506
2c8edc25 507C<$ref1 = $ref2> has been optimized.
5e50eae4 508
4b99a68c 509=item *
f4b40f11 510
2c8edc25 511Array and hash assignment are now faster, e.g.
ec34c8a4 512
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513 (..., @a) = (...);
514 (..., %h) = (...);
f4b40f11 515
2c8edc25 516especially when the RHS is empty.
ec34c8a4 517
2c8edc25 518=item *
a049258c 519
2c8edc25 520Reduce the number of odd special cases for the C<SvSCREAM> flag.
e770df11 521
2c8edc25 522=item *
a049258c 523
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524Avoid sv_catpvn() in do_vop() when unneeded.
525
526=item *
527
528Enhancements in Regex concat COW implementation.
529
530=item *
531
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532Clearing hashes and arrays has been made slightly faster. Now code
533like this is around 5% faster:
534
535 my @a;
536 for my $i (1..3_000_000) {
537 @a = (1,2,3);
538 @a = ();
539 }
540
541and this code around 3% faster:
542
543 my %h;
544 for my $i (1..3_000_000) {
545 %h = qw(a 1 b 2);
546 %h = ();
547 }
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548
549=item *
550
551Better optimise array and hash assignment
552
553=item *
554
555Converting a single-digit string to a number is now substantially faster.
556
557=item *
558
559The internal op implementing the C<split> builtin has been simplified and
560sped up. Firstly, it no longer requires a subsidiary internal C<pushre> op
561to do its work. Secondly, code of the form C<my @x = split(...)> is now
562optimised in the same way as C<@x = split(...)>, and is therefore a few
563percent faster.
564
565=item *
566
567The rather slow implementation for the experimental subroutine signatures
568feature has been made much faster; it is now comparable in speed with the
569old-style C<my ($a, $b, @c) = @_>.
7ca0bfc4 570
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571=item *
572
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573Bareword constant strings are now permitted to take part in constant
574folding. They were originally exempted from constant folding in August 1999,
575during the development of Perl 5.6, to ensure that C<use strict "subs">
576would still apply to bareword constants. That has now been accomplished a
577different way, so barewords, like other constants, now gain the performance
578benefits of constant folding.
579
580This also means that void-context warnings on constant expressions of
581barewords now report the folded constant operand, rather than the operation;
582this matches the behaviour for non-bareword constants.
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583
584=back
585
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586=head1 Modules and Pragmata
587
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588=head2 Updated Modules and Pragmata
589
590=over 4
fbe3f407 591
759020c9 592=item *
7ca0bfc4 593
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594L<Archive::Tar> has been upgraded from version 2.04 to 2.24.
595
596=item *
597
598L<arybase> has been upgraded from version 0.11 to 0.12.
599
600=item *
601
602L<attributes> has been upgraded from version 0.27 to 0.29.
a049258c 603
2c8edc25
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604The deprecation message for the C<:unique> and C<:locked> attributes
605now mention they will disappear in Perl 5.28.
a049258c 606
2c8edc25 607=item *
a049258c 608
0cc8c746
S
609L<B> has been upgraded from version 1.62 to 1.68.
610
611=item *
612
613L<B::Concise> has been upgraded from version 0.996 to 0.999.
2c8edc25
S
614
615Its output is now more descriptive for C<op_private> flags.
d5c7a4fc 616
759020c9
S
617=item *
618
0cc8c746
S
619L<B::Debug> has been upgraded from version 1.23 to 1.24.
620
621=item *
622
623L<B::Deparse> has been upgraded from version 1.37 to 1.40.
624
625=item *
626
2c8edc25 627L<B::Xref> has been upgraded from version 1.05 to 1.06.
a049258c 628
2c8edc25 629It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
a049258c 630
2c8edc25 631=item *
a049258c 632
0cc8c746
S
633L<base> has been upgraded from version 2.23 to 2.25.
634
635=item *
636
637L<bignum> has been upgraded from version 0.42 to 0.47.
638
639=item *
640
641L<Carp> has been upgraded from version 1.40 to 1.42.
642
643=item *
644
645L<charnames> has been upgraded from version 1.43 to 1.44.
646
647=item *
648
649L<Compress::Raw::Bzip2> has been upgraded from version 2.069 to 2.074.
650
651=item *
652
653L<Compress::Raw::Zlib> has been upgraded from version 2.069 to 2.074.
654
655=item *
656
657L<Config::Perl::V> has been upgraded from version 0.25 to 0.28.
658
659=item *
660
661L<CPAN> has been upgraded from version 2.11 to 2.18.
662
663=item *
664
665L<CPAN::Meta> has been upgraded from version 2.150005 to 2.150010.
666
667=item *
668
669L<Data::Dumper> has been upgraded from version 2.160 to 2.167.
a049258c 670
2c8edc25 671The XS implementation now supports Deparse.
a049258c 672
2c8edc25 673This fixes a stack management bug. [perl #130487].
a049258c 674
2c8edc25 675=item *
a049258c 676
0cc8c746
S
677L<DB_File> has been upgraded from version 1.835 to 1.840.
678
679=item *
680
681L<Devel::Peek> has been upgraded from version 1.23 to 1.26.
682
683=item *
684
685L<Devel::PPPort> has been upgraded from version 3.32 to 3.35.
686
687=item *
688
2c8edc25 689L<Devel::SelfStubber> has been upgraded from version 1.05 to 1.06.
a049258c 690
2c8edc25 691It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
a049258c 692
2c8edc25 693=item *
a049258c 694
0cc8c746 695L<diagnostics> has been upgraded from version 1.34 to 1.36.
a049258c 696
2c8edc25 697It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
7ca0bfc4 698
ad5c8857 699=item *
7ca0bfc4 700
0cc8c746
S
701L<Digest> has been upgraded from version 1.17 to 1.17_01.
702
703=item *
704
705L<Digest::MD5> has been upgraded from version 2.54 to 2.55.
706
707=item *
708
709L<Digest::SHA> has been upgraded from version 5.95 to 5.96.
710
711=item *
712
713L<DynaLoader> has been upgraded from version 1.38 to 1.42.
714
715=item *
716
717L<Encode> has been upgraded from version 2.80 to 2.88.
718
719=item *
720
721L<encoding> has been upgraded from version 2.17 to 2.19.
8f7edc68 722
2c8edc25
S
723This module's default mode is no longer supported as of Perl 5.25.3. It now
724dies when imported, unless the C<Filter> option is being used.
d5c7a4fc 725
2c8edc25 726=item *
d5c7a4fc 727
2c8edc25 728L<encoding::warnings> has been upgraded from version 0.12 to 0.13.
a049258c 729
2c8edc25
S
730This module is no longer supported as of Perl 5.25.3. It emits a warning to
731that effect and then does nothing.
a049258c 732
2c8edc25 733=item *
d5c7a4fc 734
0cc8c746 735L<Errno> has been upgraded from version 1.25 to 1.28.
a049258c 736
2c8edc25 737Document that using C<%!> loads Errno for you.
d5c7a4fc 738
2c8edc25 739It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
3abe9611 740
c714fb1f 741=item *
3ce6a296 742
2c8edc25 743L<ExtUtils::Embed> has been upgraded from version 1.33 to 1.34.
a049258c 744
2c8edc25 745It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
a049258c 746
2c8edc25 747=item *
a049258c 748
0cc8c746
S
749L<ExtUtils::MakeMaker> has been upgraded from version 7.10_01 to 7.24.
750
751=item *
752
753L<ExtUtils::Miniperl> has been upgraded from version 1.05 to 1.06.
754
755=item *
756
757L<ExtUtils::ParseXS> has been upgraded from version 3.31 to 3.34.
758
759=item *
760
761L<ExtUtils::Typemaps> has been upgraded from version 3.31 to 3.34.
762
763=item *
764
765L<feature> has been upgraded from version 1.42 to 1.47.
2c8edc25
S
766
767Fixes the Unicode Bug in the range operator.
a049258c
S
768
769=item *
5c92a635 770
0cc8c746
S
771L<File::Copy> has been upgraded from version 2.31 to 2.32.
772
773=item *
774
775L<File::Fetch> has been upgraded from version 0.48 to 0.52.
776
777=item *
778
779L<File::Glob> has been upgraded from version 1.26 to 1.28.
d5c7a4fc 780
2c8edc25 781Issue a deprecation message for C<File::Glob::glob()>.
d5c7a4fc 782
2c8edc25 783=item *
d5c7a4fc 784
0cc8c746
S
785L<File::Spec> has been upgraded from version 3.63 to 3.67.
786
787=item *
788
789L<FileHandle> has been upgraded from version 2.02 to 2.03.
790
791=item *
792
2c8edc25 793L<Filter::Simple> has been upgraded from version 0.92 to 0.93.
a049258c 794
2c8edc25
S
795It no longer treats C<no MyFilter> immediately following C<use MyFilter> as
796end-of-file. [perl #107726]
64afbd29
DM
797
798=item *
799
0cc8c746
S
800L<Getopt::Long> has been upgraded from version 2.48 to 2.49.
801
802=item *
803
804L<Getopt::Std> has been upgraded from version 1.11 to 1.12.
805
806=item *
807
808L<Hash::Util> has been upgraded from version 0.19 to 0.22.
809
810=item *
811
812L<HTTP::Tiny> has been upgraded from version 0.056 to 0.070.
a049258c 813
2c8edc25 814Internal 599-series errors now include the redirect history.
a049258c 815
2c8edc25 816=item *
a049258c 817
0cc8c746 818L<I18N::LangTags> has been upgraded from version 0.40 to 0.42.
a049258c 819
2c8edc25 820It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
a049258c 821
2c8edc25 822=item *
a049258c 823
0cc8c746
S
824L<IO> has been upgraded from version 1.36 to 1.38.
825
826=item *
827
601d9a87 828IO-Compress has been upgraded from version 2.069 to 2.074.
0cc8c746
S
829
830=item *
831
832L<IO::Socket::IP> has been upgraded from version 0.37 to 0.38.
833
834=item *
835
836L<IPC::Cmd> has been upgraded from version 0.92 to 0.96.
837
838=item *
839
840L<IPC::SysV> has been upgraded from version 2.06_01 to 2.07.
841
842=item *
843
844L<JSON::PP> has been upgraded from version 2.27300 to 2.27400_02.
845
846=item *
847
2c8edc25
S
848L<lib> has been upgraded from version 0.63 to 0.64.
849
850It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
faab9793 851
c714fb1f 852=item *
ad5c8857 853
0cc8c746
S
854L<List::Util> has been upgraded from version 1.42_02 to 1.46_02.
855
856=item *
857
858L<Locale::Codes> has been upgraded from version 3.37 to 3.42.
859
860=item *
861
862L<Locale::Maketext> has been upgraded from version 1.26 to 1.28.
863
864=item *
865
866L<Locale::Maketext::Simple> has been upgraded from version 0.21 to 0.21_01.
867
868=item *
869
870L<Math::BigInt> has been upgraded from version 1.999715 to 1.999806.
ad5c8857 871
2c8edc25 872There have also been some core customizations.
ad5c8857 873
2c8edc25 874=item *
2e0dcc12 875
0cc8c746
S
876L<Math::BigInt::FastCalc> has been upgraded from version 0.40 to 0.5005.
877
878=item *
879
880L<Math::BigRat> has been upgraded from version 0.260802 to 0.2611.
881
882=item *
883
884L<Math::Complex> has been upgraded from version 1.59 to 1.5901.
885
886=item *
887
888L<Memoize> has been upgraded from version 1.03 to 1.03_01.
889
890=item *
891
892L<Module::CoreList> has been upgraded from version 5.20170420 to 5.20170520.
893
894=item *
895
896L<Module::Load::Conditional> has been upgraded from version 0.64 to 0.68.
897
898=item *
899
900L<Module::Metadata> has been upgraded from version 1.000031 to 1.000033.
901
902=item *
903
904L<mro> has been upgraded from version 1.18 to 1.20.
905
906=item *
907
908L<Net::Ping> has been upgraded from version 2.43 to 2.55.
d5c7a4fc 909
2c8edc25
S
910IPv6 addresses and C<AF_INET6> sockets are now supported, along with several
911other enhancements.
d5c7a4fc 912
2c8edc25
S
913Remove sudo from 500_ping_icmp.t.
914
915Avoid stderr noise in tests
916
917Check for echo in new Net::Ping tests.
d5c7a4fc 918
a049258c 919=item *
d5c7a4fc 920
0cc8c746
S
921L<NEXT> has been upgraded from version 0.65 to 0.67.
922
923=item *
924
925L<Opcode> has been upgraded from version 1.34 to 1.39.
926
927=item *
928
929L<open> has been upgraded from version 1.10 to 1.11.
930
931=item *
932
2c8edc25 933L<OS2::Process> has been upgraded from version 1.11 to 1.12.
a049258c 934
2c8edc25 935It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
a049258c 936
2c8edc25 937=item *
a049258c 938
2c8edc25 939L<overload> has been upgraded from version 1.26 to 1.28.
a049258c 940
2c8edc25 941Its compilation speed has been improved slightly.
a049258c 942
2c8edc25
S
943=item *
944
0cc8c746
S
945L<parent> has been upgraded from version 0.234 to 0.236.
946
947=item *
948
2c8edc25
S
949L<perl5db.pl> has been upgraded from version 1.50 to 1.51.
950
951Ignore F</dev/tty> on non-Unix systems. [perl #113960]
952
953=item *
954
0cc8c746
S
955L<Perl::OSType> has been upgraded from version 1.009 to 1.010.
956
957=item *
958
959L<perlfaq> has been upgraded from version 5.021010 to 5.021011.
960
961=item *
962
963L<PerlIO> has been upgraded from version 1.09 to 1.10.
964
965=item *
966
967L<PerlIO::encoding> has been upgraded from version 0.24 to 0.25.
968
969=item *
970
971L<PerlIO::scalar> has been upgraded from version 0.24 to 0.26.
972
973=item *
974
975L<Pod::Checker> has been upgraded from version 1.60 to 1.73.
976
977=item *
978
979L<Pod::Functions> has been upgraded from version 1.10 to 1.11.
980
981=item *
982
983L<Pod::Html> has been upgraded from version 1.22 to 1.2202.
984
985=item *
986
987L<Pod::Perldoc> has been upgraded from version 3.25_02 to 3.28.
988
989=item *
990
991L<Pod::Simple> has been upgraded from version 3.32 to 3.35.
992
993=item *
994
995L<Pod::Usage> has been upgraded from version 1.68 to 1.69.
996
997=item *
998
999L<POSIX> has been upgraded from version 1.65 to 1.76. This remedies several
2c8edc25
S
1000defects in making its symbols exportable. [perl #127821]
1001The C<POSIX::tmpnam()> interface has been removed,
1002see L</"POSIX::tmpnam() has been removed">.
1003Trying to import POSIX subs that have no real implementations
1004(like C<POSIX::atend()>) now fails at import time, instead of
1005waiting until runtime.
1006
1007=item *
1008
0cc8c746 1009L<re> has been upgraded from version 0.32 to 0.34
2c8edc25
S
1010
1011This adds support for the new L<C<E<47>xx>|perlre/E<sol>x and E<sol>xx>
1012regular expression pattern modifier, and a change to the L<S<C<use re
1013'strict'>>|re/'strict' mode> experimental feature. When S<C<re
1014'strict'>> is enabled, a warning now will be generated for all
1015unescaped uses of the two characters C<}> and C<]> in regular
1016expression patterns (outside bracketed character classes) that are taken
1017literally. This brings them more in line with the C<)> character which
1018is always a metacharacter unless escaped. Being a metacharacter only
1019sometimes, depending on action at a distance, can lead to silently
1020having the pattern mean something quite different than was intended,
1021which the S<C<re 'strict'>> mode is intended to minimize.
1022
1023=item *
1024
0cc8c746
S
1025L<Safe> has been upgraded from version 2.39 to 2.40.
1026
1027=item *
1028
1029L<Scalar::Util> has been upgraded from version 1.42_02 to 1.46_02.
1030
1031=item *
1032
1033L<Storable> has been upgraded from version 2.56 to 2.62.
2c8edc25
S
1034
1035Fixes [perl #130098].
1036
1037=item *
1038
0cc8c746
S
1039L<Symbol> has been upgraded from version 1.07 to 1.08.
1040
1041=item *
1042
1043L<Sys::Syslog> has been upgraded from version 0.33 to 0.35.
1044
1045=item *
1046
1047L<Term::ANSIColor> has been upgraded from version 4.04 to 4.06.
1048
1049=item *
1050
2c8edc25
S
1051L<Term::ReadLine> has been upgraded from version 1.15 to 1.16.
1052
1053It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
1054
1055=item *
1056
0cc8c746 1057L<Test> has been upgraded from version 1.28 to 1.30.
2c8edc25
S
1058
1059It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
1060
1061=item *
1062
0cc8c746
S
1063L<Test::Harness> has been upgraded from version 3.36 to 3.38.
1064
1065=item *
1066
1067L<Test::Simple> has been upgraded from version 1.001014 to 1.302073.
1068
1069=item *
1070
1071L<Thread::Queue> has been upgraded from version 3.09 to 3.12.
1072
1073=item *
1074
2c8edc25
S
1075L<Thread::Semaphore> has been upgraded from 2.12 to 2.13.
1076
1077Added the C<down_timed> method.
1078
1079=item *
1080
0cc8c746 1081L<threads> has been upgraded from version 2.07 to 2.15.
2c8edc25
S
1082
1083Compatibility with 5.8 has been restored.
1084
1085Fixes [perl #130469].
1086
1087=item *
1088
0cc8c746 1089L<threads::shared> has been upgraded from version 1.51 to 1.56.
2c8edc25
S
1090
1091This fixes [cpan #119529], [perl #130457]
1092
1093=item *
1094
0cc8c746
S
1095L<Tie::Hash::NamedCapture> has been upgraded from version 0.09 to 0.10.
1096
1097=item *
1098
1099L<Time::HiRes> has been upgraded from version 1.9733 to 1.9741.
2c8edc25
S
1100
1101It now builds on systems with C++11 compilers (such as G++ 6 and Clang++
11023.9).
1103
1104Now uses C<clockid_t>.
1105
1106=item *
1107
0cc8c746
S
1108L<Time::Local> has been upgraded from version 1.2300 to 1.25.
1109
1110=item *
1111
1112L<Unicode::Collate> has been upgraded from version 1.14 to 1.19.
1113
1114=item *
1115
1116L<Unicode::UCD> has been upgraded from version 0.64 to 0.68.
2c8edc25
S
1117
1118It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
1119
1120=item *
1121
0cc8c746
S
1122L<version> has been upgraded from version 0.9916 to 0.9917.
1123
1124=item *
1125
1126L<VMS::DCLsym> has been upgraded from version 1.06 to 1.08.
2c8edc25
S
1127
1128It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
a049258c
S
1129
1130=item *
1131
0cc8c746
S
1132L<warnings> has been upgraded from version 1.36 to 1.37.
1133
1134=item *
1135
1136L<XS::Typemap> has been upgraded from version 0.14 to 0.15.
1137
1138=item *
1139
1140L<XSLoader> has been upgraded from version 0.21 to 0.27.
2c8edc25
S
1141
1142Fixed a security hole in which binary files could be loaded from a path
1143outside of L<C<@INC>|perlvar/@INC>.
1144
1145It now uses 3-arg C<open()> instead of 2-arg C<open()>. [perl #130122]
a049258c
S
1146
1147=back
1148
2c8edc25
S
1149=head1 Documentation
1150
1151=head2 New Documentation
a049258c 1152
2c8edc25 1153=head3 L<perldeprecation>
a049258c 1154
2c8edc25
S
1155This file documents all upcoming deprecations, and some of the deprecations
1156which already have been removed. The purpose of this documentation is
1157two-fold: document what will disappear, and by which version, and serve
1158as a guide for people dealing with code which has features that no longer
1159work after an upgrade of their perl.
a049258c 1160
2c8edc25 1161=head2 Changes to Existing Documentation
a049258c 1162
2c8edc25 1163=head3 L<perlcall>
a049258c
S
1164
1165=over 4
1166
2c8edc25
S
1167=item *
1168
1169Use of unassigned code point or non-standalone grapheme for a delimiter will be a fatal error starting in Perl 5.30
a049258c 1170
2c8edc25
S
1171This was changed to drop a leading C<v> in C<v5.30>, so it uses the same
1172style as other deprecation messages.
a049258c 1173
2c8edc25
S
1174=item *
1175
1176"\c%c" is more clearly written simply as "%s".
1177
1178It 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>
1179
1180=item *
1181
1182Removed redundant C<dSP> from an example.
a049258c 1183
2c8edc25 1184=back
a049258c 1185
2c8edc25 1186=head3 L<perlcommunity>
a049258c
S
1187
1188=over 4
1189
2c8edc25 1190=item *
a049258c 1191
2c8edc25 1192All references to Usenet have been removed.
a049258c
S
1193
1194=back
1195
2c8edc25
S
1196=head3 L<perldata>
1197
1198=over 4
1199
1200=item *
1201
1202Updated documentation of C<scalar(%hash)>. See L</scalar(%hash) return
1203signature changed> above.
1204
1205=item *
a049258c 1206
2c8edc25
S
1207Use of single character variables, with the variable name a non printable
1208character in the range C<\x80>-C<\xFF> is no longer allowed. Update the docs to
1209reflect this.
1210
1211=back
1212
1213=head3 L<perldelta>
a049258c
S
1214
1215=over 4
1216
2c8edc25 1217=item *
a049258c 1218
2c8edc25 1219All references to Usenet have been removed.
a049258c
S
1220
1221=back
1222
2c8edc25
S
1223=head3 L<perldiag>
1224
1225=over 4
1226
1227=item *
1228
1229Deprecations are to be marked with a D.
1230C<"%s() is deprecated on :utf8 handles"> use a deprecation message, and as
1231such, such be marked C<"(D deprecated)"> and not C<"(W deprecated)">.
a049258c 1232
2c8edc25 1233=back
a049258c 1234
2c8edc25 1235=head3 L<perlexperiment>
a049258c
S
1236
1237=over 4
1238
1239=item *
1240
2c8edc25 1241Documented new feature: See L</Declaring a reference to a variable> above.
a049258c
S
1242
1243=back
1244
2c8edc25
S
1245=head3 L<perlfunc>
1246
1247=over 4
1248
1249=item *
1250
1251Defined on aggregates is no longer allowed. Perlfunc was still reporting it as
1252deprecated, and that it will be deleted in the future.
1253
1254=item *
1255
1256Clarified documentation of L<C<seek()>|perlfunc/seek>,
1257L<C<tell()>|perlfunc/tell> and L<C<sysseek()>|perlfunc/sysseek>.
1258L<[perl #128607]|https://rt.perl.org/Public/Bug/Display.html?id=128607>
a049258c 1259
2c8edc25
S
1260=item *
1261
1262Removed obsolete documentation of L<C<study()>|perlfunc/study>.
1263
1264=back
a049258c 1265
2c8edc25 1266=head3 L<perlguts>
a049258c
S
1267
1268=over 4
1269
1270=item *
1271
2c8edc25 1272Add C<pTHX_> to magic method examples.
a049258c
S
1273
1274=back
1275
2c8edc25
S
1276=head3 L<perlhack>
1277
1278=over 4
1279
1280=item *
1281
1282Document Tab VS Space.
a049258c 1283
2c8edc25 1284=back
a049258c 1285
2c8edc25 1286=head3 L<perlinterp>
a049258c
S
1287
1288=over 4
1289
1290=item *
1291
2c8edc25
S
1292L<perlinterp> has been expanded to give a more detailed example of how to
1293hunt around in the parser for how a given operator is handled.
a049258c
S
1294
1295=back
1296
2c8edc25 1297=head3 L<perllocale>
a049258c
S
1298
1299=over 4
1300
1301=item *
1302
2c8edc25
S
1303Document C<NUL> collation handling.
1304
1305=item *
1306
1307Some locales aren't compatible with Perl. Note the potential bad
1308consequences of using them.
a049258c
S
1309
1310=back
1311
2c8edc25
S
1312=head3 L<perlmodinstall>
1313
1314=over 4
1315
1316=item *
1317
1318All references to Usenet have been removed.
1319
1320=back
1321
1322=head3 L<perlmodlib>
1323
1324=over 4
1325
1326=item *
1327
1328Updated the mirror list.
1329
1330=item *
1331
1332All references to Usenet have been removed.
1333
1334=back
1335
1336=head3 L<perlnewmod>
1337
1338=over 4
1339
1340=item *
1341
1342All references to Usenet have been removed.
1343
1344=back
1345
1346=head3 L<perlobj>
1347
1348=over 4
1349
1350=item *
1351
1352Added a section on calling methods using their fully qualified names.
1353
1354=item *
1355
1356Do not discourage manual @ISA.
1357
1358=back
1359
1360=head3 L<perlootut>
1361
1362=over 4
1363
1364=item *
1365
1366Tidy the document.
1367
1368=item *
1369
1370Mention C<Moo> more.
1371
1372=back
1373
1374=head3 L<perlop>
1375
1376=over 4
1377
1378=item *
1379
1380Clarify behavior single quote regexps.
1381
1382=back
1383
1384=head3 L<perlre>
1385
1386=over 4
1387
1388=item *
1389
1390Several minor enhancements to the documentation.
1391
1392=back
1393
1394=head3 L<perlsec>
1395
1396=over 4
1397
1398=item *
1399
1400Fixed link to Crosby paper on hash complexity attack.
1401
1402=back
1403
1404=head3 L<perlref>
1405
1406=over 4
1407
1408=item *
1409
1410Documented new feature: See L</Declaring a reference to a variable> above.
1411
1412=back
1413
1414=head3 L<perltie>
1415
1416=over 4
1417
1418=item *
1419
1420Updated documentation of C<scalar(%hash)>. See L</scalar(%hash) return
1421signature changed> above.
1422
1423=back
1424
1425=head3 L<perlunicode>
1426
1427=over 4
1428
1429=item *
1430
1431Documented change to C<\p{I<script>}> to now use the improved Script_Extensions
1432property. See L</Use of \p{script} uses the improved Script_Extensions
1433property> above.
1434
1435=item *
1436
1437Updated the text to correspond with changes in Unicode UTS#18, concerning
1438regular expressions, and Perl compatibility with what it says.
1439
1440=back
1441
1442=head3 L<perlvar>
1443
1444=over 4
1445
1446=item *
1447
1448Removed obsolete documentation of C<${^ENCODING}>. See L</${^ENCODING} has
1449been removed> above.
1450
1451=item *
1452
1453Document C<@ISA>. Was documented other places, not not in L<perlvar>.
1454
1455=back
1456
1457=head1 Diagnostics
1458
1459=head2 New Diagnostics
1460
1461=head3 New Errors
1462
1463=over 4
1464
1465=item *
1466
1467Since C<.> is now removed from C<@INC> by default, C<do> will now trigger
1468a warning recommending to fix the C<do> statement:
1469
1470L<do "%s" failed, '.' is no longer in @INC|perldiag/do "%s" failed, '.' is no longer in @INC; did you mean do ".E<sol>%s"?>
1471
1472=item *
1473
1474Using the empty pattern (which re-executes the last successfully-matched
1475pattern) inside a code block in another regex, as in C</(?{ s!!new! })/>, has
4f73c567
S
1476always previously yielded a segfault. It now produces an error:
1477L<Infinite recursion in regex|perldiag/"Infinite recursion in regex">.
2c8edc25
S
1478
1479=item *
1480
1481L<The experimental declared_refs feature is not enabled|perldiag/"The experimental declared_refs feature is not enabled">
1482
1483(F) To declare references to variables, as in C<my \%x>, you must first enable
1484the feature:
1485
1486 no warnings "experimental::declared_refs";
1487 use feature "declared_refs";
1488
1489=item *
1490
1491L<Version control conflict marker|perldiag/"Version control conflict marker">
1492
e6abae1c 1493(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
1494C<E<gt>E<gt>E<gt>E<gt>E<gt>E<gt>E<gt>>, or C<=======>. These may be left by a
1495version control system to mark conflicts after a failed merge operation.
1496
1497=item *
1498
1499L<%s: command not found|perldiag/"%s: command not found">
1500
1501(A) You've accidentally run your script through B<bash> or another shell
1502instead of Perl. Check the #! line, or manually feed your script into
1503Perl yourself. The #! line at the top of your file could look like:
1504
1505 #!/usr/bin/perl
1506
1507=item *
1508
1509L<%s: command not found: %s|perldiag/"%s: command not found: %s">
1510
1511(A) You've accidentally run your script through B<zsh> or another shell
1512instead of Perl. Check the #! line, or manually feed your script into
1513Perl yourself. The #! line at the top of your file could look like:
1514
1515 #!/usr/bin/perl
1516
1517=item *
1518
e6abae1c 1519L<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
1520
1521Unescaped left braces are already illegal in some contexts in regular
1522expression patterns, but, due to an oversight, no deprecation warning
1523was raised in other contexts where they are intended to become illegal.
1524This warning is now raised in these contexts.
1525
1526=item *
1527
1528L<Bareword in require contains "%s"|perldiag/"Bareword in require contains "%s"">
1529
1530=item *
1531
1532L<Bareword in require maps to empty filename|perldiag/"Bareword in require maps to empty filename">
1533
1534=item *
1535
1536L<Bareword in require maps to disallowed filename "%s"|perldiag/"Bareword in require maps to disallowed filename "%s"">
1537
1538=item *
1539
1540L<Bareword in require must not start with a double-colon: "%s"|perldiag/"Bareword in require must not start with a double-colon: "%s"">
1541
1542=back
1543
1544=head3 New Warnings
1545
1546=over 4
1547
1548=item *
1549
4f73c567 1550L<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
1551
1552See L</Deprecations>
1553
1554=item *
1555
1556L<Declaring references is experimental|perldiag/"Declaring references is experimental">
1557
1558(S experimental::declared_refs) This warning is emitted if you use a reference
1559constructor on the right-hand side of C<my()>, C<state()>, C<our()>, or
1560C<local()>. Simply suppress the warning if you want to use the feature, but
1561know that in doing so you are taking the risk of using an experimental feature
1562which may change or be removed in a future Perl version:
1563
1564 no warnings "experimental::declared_refs";
1565 use feature "declared_refs";
1566 $fooref = my \$foo;
1567
1568=item *
1569
4f73c567 1570L<C<${^ENCODING}> is no longer supported. Its use will be fatal in Perl 5.28|perldiag/"${^ENCODING} is no longer supported. Its use will be fatal in Perl 5.28">
2c8edc25
S
1571
1572(D deprecated) The special variable C<${^ENCODING}>, formerly used to implement
1573the C<encoding> pragma, is no longer supported as of Perl 5.26.0.
1574
89853d76
DH
1575=item *
1576
1577Since C<.> is now removed from C<@INC> by default, C<do> will now trigger
1578a warning recommending to fix the C<do> statement:
1579
fc902710 1580L<do "%s" failed, '.' is no longer in @INC|perldiag/do "%s" failed, '.' is no longer in @INC; did you mean do ".E<sol>%s"?>
89853d76 1581
2c8edc25
S
1582=back
1583
1584=head2 Changes to Existing Diagnostics
1585
1586=over 4
1587
1588=item *
1589
1590When a C<require> fails, we now do not provide C<@INC> when the C<require>
1591is for a file instead of a module.
1592
1593=item *
1594
1595When C<@INC> is not scanned for a C<require> call, we no longer display
1596C<@INC> to avoid confusion.
1597
1598=item *
1599
1600Attribute "locked" is deprecated, and will disappear in Perl 5.28
1601
1602=item *
1603
1604Attribute "unique" is deprecated, and will disappear in Perl 5.28
1605
1606=item *
1607
1608Constants from lexical variables potentially modified elsewhere are
1609deprecated. This will not be allowed in Perl 5.32
1610
1611=item *
1612
1613Deprecated use of my() in false conditional. This will be a fatal error
1614in Perl 5.30
1615
1616=item *
1617
1618dump() better written as CORE::dump(). dump() will no longer be available
1619in Perl 5.30
1620
1621=item *
1622
1623${^ENCODING} is no longer supported. Its use will be fatal in Perl 5.28
1624
1625=item *
1626
1627File::Glob::glob() will disappear in perl 5.30. Use File::Glob::bsd_glob()
1628instead.
1629
1630=item *
1631
1632%s() is deprecated on :utf8 handles. This will be a fatal error in Perl 5.30
1633
1634=item *
1635
1636$* is no longer supported. Its use will be fatal in Perl 5.30
1637
1638=item *
1639
1640$* is no longer supported. Its use will be fatal in Perl 5.30
1641
1642=item *
1643
1644Opening dirhandle %s also as a file. This will be a fatal error in Perl 5.28
1645
1646=item *
1647
1648Opening filehandle %s also as a directory. This will be a fatal
1649error in Perl 5.28
1650
1651=item *
1652
1653Setting $/ to a reference to %s as a form of slurp is deprecated,
1654treating as undef. This will be fatal in Perl 5.28
1655
1656=item *
1657
1658Unescaped left brace in regex is deprecated here (and will be fatal
1659in Perl 5.30), passed through in regex; marked by S<< E<lt>-- HERE >> in m/%s/
1660
1661=item *
1662
1663Unknown charname '' is deprecated. Its use will be fatal in Perl 5.28
1664
1665=item *
1666
1667Use of bare E<lt>E<lt> to mean E<lt>E<lt>"" is deprecated. Its use will be fatal in Perl 5.28
1668
1669=item *
1670
1671Use of code point 0x%s is deprecated; the permissible max is 0x%s.
1672This will be fatal in Perl 5.28
1673
1674=item *
1675
1676Use of comma-less variable list is deprecated. Its use will be fatal
1677in Perl 5.28
1678
1679=item *
1680
1681Use of inherited AUTOLOAD for non-method %s() is deprecated. This
1682will be fatal in Perl 5.28
1683
1684=item *
1685
1686Use of strings with code points over 0xFF as arguments to %s operator
1687is deprecated. This will be a fatal error in Perl 5.28
1688
1689=item *
1690
1691Improve error for missing tie() package/method. This brings the error messages
1692in line with the ones used for normal method calls, despite not using
1693call_method().
1694
1695=item *
1696
1697Make the sysread()/syswrite/() etc :utf8 handle warnings default. These
1698warnings were under 'deprecated' previously.
1699
1700=item *
1701
1702'do' errors now refer to 'do' (not 'require').
1703
1704=item *
1705
1706Details as to the exact problem have been added to the diagnostics that
1707occur when malformed UTF-8 is encountered when trying to convert to a
1708code point.
1709
1710=item *
1711
1712Executing C<undef $x> where C<$x> is tied or magical no longer incorrectly
1713blames the variable for an uninitialized-value warning encountered by the
1714tied/magical code.
1715
1716=item *
1717
e6abae1c 1718L<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
1719
1720The word "here" has been added to the message that was raised in
1721v5.25.1. This is to indicate that there are contexts in which unescaped
1722left braces are not (yet) illegal.
1723
1724=item *
1725
1726Code like C<$x = $x . "a"> was incorrectly failing to yield a
1727L<use of uninitialized value|perldiag/"Use of uninitialized value%s">
1728warning when C<$x> was a lexical variable with an undefined value. That has
1729now been fixed. [perl #127877]
1730
1731=item *
1732
1733When the error "Experimental push on scalar is now forbidden" is raised for
1734the hash functions C<keys>, C<each>, and C<values>, it is now followed by
1735the more helpful message, "Type of arg 1 to whatever must be hash or
1736array". [perl #127976]
1737
1738=item *
1739
1740C<undef *_; shift> or C<undef *_; pop> inside a subroutine, with no
1741argument to C<shift> or C<pop>, began crashing in Perl 5.14.0, but has now
1742been fixed.
1743
1744=item *
1745
1746C<< "string$scalar-E<gt>$*" >> now correctly prefers concat overloading to
1747string overloading if C<< $scalar-E<gt>$* >> returns an overloaded object,
1748bringing it into consistency with C<$$scalar>.
1749
1750=item *
1751
1752C<< /@0{0*-E<gt>@*/*0 >> and similar contortions used to crash, but no longer
1753do, but merely produce a syntax error. [perl #128171]
1754
1755=item *
1756
1757C<do> or C<require> with a reference or typeglob which, when stringified,
1758contains a null character started crashing in Perl 5.20.0, but has now been
1759fixed. [perl #128182]
1760
1761=back
1762
1763=head1 Utility Changes
1764
1765=head2 F<c2ph> and F<pstruct>
1766
1767=over 4
1768
1769=item *
1770
1771These old utilities have long since superceded by L<h2xs>, and are
1772now gone from the distribution.
1773
1774=back
1775
1776=head2 F<Porting/pod_lib.pl>
1777
1778=over 4
1779
1780=item *
1781
1782Removed spurious executable bit.
1783
1784=item *
1785
1786Account for possibility of DOS file endings.
1787
1788=back
1789
1790=head2 F<Porting/sync-with-cpan>
1791
1792=over 4
1793
1794=item *
1795
1796Many improvements
1797
1798=back
1799
1800=head2 F<perf/benchmarks>
1801
1802=over 4
1803
1804=item *
1805
1806Tidy file, rename some symbols.
1807
1808=back
1809
1810=head2 F<Porting/checkAUTHORS.pl>
1811
1812=over 4
1813
1814=item *
1815
1816Replace obscure character range with \w.
1817
1818=back
1819
1820=head2 F<t/porting/regen.t>
1821
1822=over 4
1823
1824=item *
1825
1826try to be more helpful when tests fail.
1827
1828=back
1829
1830=head2 F<utils/h2xs.PL>
1831
1832=over 4
1833
1834=item *
1835
1836Avoid infinite loop for enums.
1837
1838=back
1839
1840=head2 L<perlbug>
1841
1842=over 4
1843
1844=item *
1845
1846Long lines in the message body are now wrapped at 900 characters, to stay
1847well within the 1000-character limit imposed by SMTP mail transfer agents.
1848This is particularly likely to be important for the list of arguments to
1849C<Configure>, which can readily exceed the limit if, for example, it names
1850several non-default installation paths. This change also adds the first unit
1851tests for perlbug. [perl #128020]
1852
1853=back
1854
1855=head1 Configuration and Compilation
1856
1857=over 4
1858
1859=item *
1860
89853d76 1861C<-Ddefault_inc_excludes_dot> has been turned on by default.
2c8edc25
S
1862
1863=item *
1864
1865The C<dtrace> build process has further changes:
1866
1867=over
1868
1869=item *
1870
1871If the C<-xnolibs> is available, use that so a F<dtrace> perl can be
1872built within a FreeBSD jail.
1873
1874=item *
1875
1876On systems that build a dtrace object file (FreeBSD, Solaris and
1877SystemTap's dtrace emulation), copy the input objects to a separate
1878directory and process them there, and use those objects in the link,
1879since C<dtrace -G> also modifies these objects.
1880
1881=item *
1882
1883Add libelf to the build on FreeBSD 10.x, since dtrace adds references
1884to libelf symbols.
1885
1886=item *
1887
1888Generate a dummy dtrace_main.o if C<dtrace -G> fails to build it. A
1889default build on Solaris generates probes from the unused inline
1890functions, while they don't on FreeBSD, which causes C<dtrace -G> to
1891fail.
1892
1893=back
1894
1895[perl #130108]
1896
1897=item *
1898
1899You can now disable perl's use of the PERL_HASH_SEED and
1900PERL_PERTURB_KEYS environment variables by configuring perl with
1901C<-Accflags=NO_PERL_HASH_ENV>.
1902
1903=item *
1904
1905You can now disable perl's use of the PERL_HASH_SEED_DEBUG environment
1906variable by configuring perl with
1907C<-Accflags=-DNO_PERL_HASH_SEED_DEBUG>.
1908
1909=item *
1910
1911Zero out the alignment bytes when calculating the bytes for 80-bit C<NaN>
1912and C<Inf> to make builds more reproducible. [perl #130133]
1913
1914=item *
1915
1916Since 5.18 for testing purposes we have included support for
1917building perl with a variety of non-standard, and non-recommended
1918hash functions. Since we do not recommend the use of these functions
1919we have removed them and their corresponding build options. Specifically
1920this includes the following build options:
1921
1922 PERL_HASH_FUNC_SDBM
1923 PERL_HASH_FUNC_DJB2
1924 PERL_HASH_FUNC_SUPERFAST
1925 PERL_HASH_FUNC_MURMUR3
1926 PERL_HASH_FUNC_ONE_AT_A_TIME
1927 PERL_HASH_FUNC_ONE_AT_A_TIME_OLD
1928 PERL_HASH_FUNC_MURMUR_HASH_64A
1929 PERL_HASH_FUNC_MURMUR_HASH_64B
1930
1931=item *
1932
1933Remove "Warning: perl appears in your path"
1934
1935This install warning is more or less obsolete, since most platforms already
1936*will* have a /usr/bin/perl or similar provided by the OS.
1937
1938=item *
1939
1940Reduce verbosity of "make install.man"
1941
1942Previously, two progress messages were emitted for each manpage: one by
1943installman itself, and one by the function in install_lib.pl that it calls to
1944actually install the file. Disabling the second of those in each case saves
1945over 750 lines of unhelpful output.
1946
1947=item *
1948
1949Cleanup for clang -Weverything support. [perl 129961]
1950
1951=item *
1952
1953Configure: signbit scan was assuming too much, stop assuming negative 0.
1954
1955=item *
1956
1957Various compiler warnings have been silenced.
1958
1959=item *
1960
1961Several smaller changes have been made to remove impediments to compiling under
1962C++11.
1963
1964=item *
1965
1966Builds using C<USE_PAD_RESET> now work again; this configuration had
1967bit-rotted.
1968
1969=item *
1970
1971A probe for C<gai_strerror> was added to F<Configure> that checks if the
1972the gai_strerror() routine is available and can be used to
1973translate error codes returned by getaddrinfo() into human
1974readable strings.
1975
1976=item *
1977
1978F<Configure> now aborts if both "-Duselongdouble" and "-Dusequadmath" are
1979requested.
1980L<[perl #126203]|https://rt.perl.org/Public/Bug/Display.html?id=126203>
1981
1982=item *
1983
1984Fixed a bug in which F<Configure> could append "-quadmath" to the archname even
1985if it was already present.
1986L<[perl #128538]|https://rt.perl.org/Public/Bug/Display.html?id=128538>
1987
1988=item *
1989
1990Clang builds with "-DPERL_GLOBAL_STRUCT" or "-DPERL_GLOBAL_STRUCT_PRIVATE" have
1991been fixed (by disabling Thread Safety Analysis for these configurations).
1992
1993=item *
1994
1995F<make_ext.pl> no longer updates a module's F<pm_to_blib> file when no
1996files require updates. This could cause dependencies, F<perlmain.c>
1997in particular, to be rebuilt unnecessarily. [perl #126710]
1998
1999=item *
2000
2001The output of C<perl -V> has been reformatted so that each configuration
2002and compile-time option is now listed one per line, to improve
2003readability.
2004
2005=item *
2006
2007C<Configure> now builds C<miniperl> and C<generate_uudmap> if you
2008invoke it with C<-Dusecrosscompiler> but not C<-Dtargethost=somehost>.
2009This means you can supply your target platform C<config.sh>, generate
2010the headers and proceed to build your cross-target perl. [perl #127234]
2011
2012=item *
2013
2014Builds with C<-Accflags=-DPERL_TRACE_OPS> now only dump the operator
2015counts when the environment variable C<PERL_TRACE_OPS> to be set to a
2016non-zero integer. This allows C<make test> to pass on such a build.
2017
2018=item *
2019
2020When building with GCC 6 and link-time optimization (the C<-flto> option to
2021C<gcc>), C<Configure> was treating all probed symbols as present on the
2022system, regardless of whether they actually exist. This has been fixed.
2023[perl #128131]
2024
2025=item *
2026
2027The F<t/test.pl> library is used for internal testing of Perl itself, and
2028also copied by several CPAN modules. Some of those modules must work on
2029older versions of Perl, so F<t/test.pl> must in turn avoid newer Perl
2030features. Compatibility with Perl 5.8 was inadvertently removed some time
2031ago; it has now been restored. [perl #128052]
2032
2033=item *
2034
2035The build process no longer emits an extra blank line before building each
2036"simple" extension (those with only F<*.pm> and F<*.pod> files).
2037
2038=back
2039
2040=head1 Testing
2041
2042=over 4
2043
2044=item *
2045
2046F<XS-APItest/t/utf8.t>: Several small fixes and enhancements.
2047
2048=item *
2049
2050Tests for locales were erroneously using locales incompatible with Perl.
2051
2052=item *
2053
2054Some parts of the test suite that try to exhaustively test edge cases in the
2055regex implementation have been restricted to running for a maximum of five
2056minutes. On slow systems they could otherwise take several hours, without
2057significantly improving our understanding of the correctness of the code
2058under test.
2059
2060In addition, some of those test cases have been split into more files, to
2061allow them to be run in parallel on suitable systems.
2062
2063=item *
2064
2065A new internal facility allows analysing the time taken by the individual
2066tests in Perl's own test suite; see F<Porting/harness-timer-report.pl>.
2067
2068=item *
2069
2070F<t/re/regexp_nonull.t> has been added to test that the regular expression
2071engine can handle scalars that do not have a null byte just past the end of
2072the string.
2073
2074=item *
2075
2076A new test script, F<t/op/decl-refs.t>, has been added to test the new feature,
2077"Declaring a reference to a variable".
2078
2079=item *
2080
2081A new test script, F<t/re/anyof.t>, has been added to test that the ANYOF nodes
2082generated by bracketed character classes are as expected.
2083
2084=item *
2085
2086F<t/harness> now tries really hard not to run tests outside of the Perl
2087source tree. [perl #124050]
2088
2089=back
2090
2091=head1 Platform Support
2092
2093=head2 New Platforms
2094
2095=over 4
2096
2097=item NetBSD/VAX
2098
2099Perl now compiles under NetBSD on VAX machines. However, it's not
2100possible for that platform to implement floating-point infinities and
2101NaNs compatibly with most modern systems, which implement the IEEE-754
2102floating point standard. The hexadecimal floating point (C<0x...p[+-]n>
2103literals, C<printf %a>) is not implemented, either.
2104The C<make test> passes 98% of tests.
2105
2106=over 4
2107
2108=item *
2109
2110Test fixes and minor updates.
2111
2112=item *
2113
2114Account for lack of C<inf>, C<nan>, and C<-0.0> support.
2115
2116=back
2117
2118=back
2119
2120=head2 Platform-Specific Notes
2121
2122=over 4
2123
2124=item Darwin
2125
2126don't treat -Dprefix=/usr as special, instead require an extra option
2127-Ddarwin_distribution to produce the same results.
2128
2129=item POSIX
2130
2131Finish removing POSIX deprecated functions.
2132
2133=item OS X
2134
2135OS X El Capitan doesn't implement the clock_gettime() or clock_getres() APIs,
2136emulate them as necessary.
2137
2138=item macOS
2139
2140Deprecated syscall(2) on macOS 10.12.
2141
2142=item EBCDIC
2143
2144Several tests have been updated to work (or be skipped) on EBCDIC platforms.
2145
2146=item HP-UX
2147
2148L<Net::Ping> UDP test is skipped on HP-UX.
2149
2150=item Hurd
2151
2152The hints for Hurd have been improved enabling malloc wrap and reporting the
2153GNU libc used (previously it was an empty string when reported).
2154
2155=item VAX
2156
2157VAX floating point formats are now supported.
2158
2159=item VMS
2160
2161=over 4
2162
2163=item *
2164
2165The path separator for the C<PERL5LIB> and C<PERLLIB> environment entries is
2166now a colon (C<:>) when running under a Unix shell. There is no change when
2167running under DCL (it's still C<|>).
2168
2169=item *
2170
2171Remove some VMS-specific hacks from C<showlex.t>. These were added 15 years
2172ago, and are no longer necessary for any VMS version now supported.
2173
2174=item *
2175
2176Move C<_pDEPTH> and C<_aDEPTH> after F<config.h> otherwise DEBUGGING
2177may not be defined yet.
2178
2179=item *
2180
2181VAXC has not been a possibility for a good long while, and the versions of the
2182DEC/Compaq/HP/VSI C compiler that report themselves as "DEC" in a listing file
2183are 15 years or more out-of-date and can be safely desupported.
2184
2185=back
2186
2187=item Windows
2188
2189=over 4
2190
2191=item *
2192
2193Support for compiling perl on Windows using Microsoft Visual Studio 2015
2194(containing Visual C++ 14.0) has been added.
2195
2196This version of VC++ includes a completely rewritten C run-time library, some
2197of the changes in which mean that work done to resolve a socket close() bug in
2198perl #120091 and perl #118059 is not workable in its current state with this
2199version of VC++. Therefore, we have effectively reverted that bug fix for
2200VS2015 onwards on the basis that being able to build with VS2015 onwards is
2201more important than keeping the bug fix. We may revisit this in the future to
2202attempt to fix the bug again in a way that is compatible with VS2015.
2203
2204These changes do not affect compilation with GCC or with Visual Studio versions
2205up to and including VS2013, i.e. the bug fix is retained (unchanged) for those
2206compilers.
2207
2208Note that you may experience compatibility problems if you mix a perl built
2209with GCC or VS E<lt>= VS2013 with XS modules built with VS2015, or if you mix a
2210perl built with VS2015 with XS modules built with GCC or VS E<lt>= VS2013.
2211Some incompatibility may arise because of the bug fix that has been reverted
2212for VS2015 builds of perl, but there may well be incompatibility anyway because
2213of the rewritten CRT in VS2015 (e.g. see discussion at
2214http://stackoverflow.com/questions/30412951).
2215
2216=back
2217
2218=item Win32
2219
2220=over 4
2221
2222=item *
2223
2224Tweaks for Win32 VC vs GCC detection makefile code. This fixes issue that CCHOME
2225depends on CCTYPE, which in auto detect mode is set after CCHOME, so CCHOME uses
2226the uninit CCTYPE var. Also fix else vs .ELSE in makefile.mk
2227
2228=item *
2229
2230fp definitions have been updated.
2231
2232=back
2233
2234=item VMS And Win32
2235
2236Fix some breakage, add 'undef' value for default_inc_excludes_dot in build
2237scripts.
2238
2239=item Linux
2240
2241Drop support for Linux a.out Linux has used ELF for over twenty years.
2242
2243=item OpenBSD 6
2244
2245OpenBSD 6 still does not support returning pid, gid or uid with SA_SIGINFO.
2246Make sure this is accounted for.
2247
2248=item FreeBSD
2249
2250t/uni/overload.t: Skip hanging test on FreeBSD.
2251
2252=back
2253
2254=head1 Internal Changes
2255
2256=over 4
2257
2258=item *
2259
2260The C<op_class()> API function has been added. This is like the existing
2261C<OP_CLASS()> macro, but can more accurately determine what struct an op
2262has been allocated as. For example C<OP_CLASS()> might return
2263C<OA_BASEOP_OR_UNOP> indicating that ops of this type are usually
2264allocated as an C<OP> or C<UNOP>; while C<op_class()> will return
2265C<OPclass_BASEOP> or C<OPclass_UNOP> as appropriate.
2266
2267=item *
2268
2269The output format of the C<op_dump()> function (as used by C<perl -Dx>)
2270has changed: it now displays an "ASCII-art" tree structure, and shows more
2271low-level details about each op, such as its address and class.
2272
2273=item *
2274
2275New versions of macros like C<isALPHA_utf8> and C<toLOWER_utf8> have
2276been added, each with the
2277suffix C<_safe>, like C<isSPACE_utf8_safe>. These take an extra
2278parameter, giving an upper limit of how far into the string it is safe
2279to read. Using the old versions could cause attempts to read beyond the
2280end of the input buffer if the UTF-8 is not well-formed, and their use
2281now raises a deprecation warning. Details are at
2282L<perlapi/Character classification>.
2283
2284=item *
2285
2286Calling macros like C<isALPHA_utf8> on malformed UTF-8 have issued a
2287deprecation warning since Perl v5.18. They now die.
2288Similarly, macros like C<toLOWER_utf8> on malformed UTF-8 now die.
2289
2290=item *
2291
2292Calling the functions C<utf8n_to_uvchr> and its derivatives, while
2293passing a string length of 0 is now asserted against in DEBUGGING
2294builds, and otherwise returns the Unicode REPLACEMENT CHARACTER. If
2295you have nothing to decode, you shouldn't call the decode function.
2296
2297=item *
2298
2299The functions C<utf8n_to_uvchr> and its derivatives now return the
2300Unicode REPLACEMENT CHARACTER if called with UTF-8 that has the overlong
2301malformation, and that malformation is allowed by the input parameters.
2302This malformation is where the UTF-8 looks valid syntactically, but
2303there is a shorter sequence that yields the same code point. This has
2304been forbidden since Unicode version 3.1.
2305
2306=item *
2307
2308The functions C<utf8n_to_uvchr> and its derivatives now accept an input
2309flag to allow the overflow malformation. This malformation is when the
2310UTF-8 may be syntactically valid, but the code point it represents is
2311not capable of being represented in the word length on the platform.
2312What "allowed" means in this case is that the function doesn't return an
2313error, and advances the parse pointer to beyond the UTF-8 in question,
2314but it returns the Unicode REPLACEMENT CHARACTER as the value of the
2315code point (since the real value is not representable).
2316
2317=item *
2318
2319The C<PADOFFSET> type has changed from being unsigned to signed, and
2320several pad-related variables such as C<PL_padix> have changed from being
2321of type C<I32> to type C<PADOFFSET>.
2322
2323=item *
2324
2325The function C<L<perlapi/utf8n_to_uvchr>> has been changed to not
2326abandon searching for other malformations when the first one is
2327encountered. A call to it thus can generate multiple diagnostics,
2328instead of just one.
2329
2330=item *
2331
2332A new function, C<L<perlapi/utf8n_to_uvchr_error>>, has been added for
2333use by modules that need to know the details of UTF-8 malformations
2334beyond pass/fail. Previously, the only ways to know why a sequence was
2335ill-formed was to capture and parse the generated diagnostics, or to do
2336your own analysis.
2337
2338=item *
2339
2340Several new functions for handling Unicode have been added to the API:
2341C<L<perlapi/is_strict_utf8_string>>,
2342C<L<perlapi/is_c9strict_utf8_string>>,
2343C<L<perlapi/is_utf8_string_flags>>,
2344C<L<perlapi/is_strict_utf8_string_loc>>,
2345C<L<perlapi/is_strict_utf8_string_loclen>>,
2346C<L<perlapi/is_c9strict_utf8_string_loc>>,
2347C<L<perlapi/is_c9strict_utf8_string_loclen>>,
2348C<L<perlapi/is_utf8_string_loc_flags>>,
2349C<L<perlapi/is_utf8_string_loclen_flags>>,
2350C<L<perlapi/is_utf8_fixed_width_buf_flags>>,
2351C<L<perlapi/is_utf8_fixed_width_buf_loc_flags>>,
2352C<L<perlapi/is_utf8_fixed_width_buf_loclen_flags>>.
2353
2354These functions are all extensions of the C<is_utf8_string_*()> functions,
2355that apply various restrictions to the UTF-8 recognized as valid.
2356
2357=item *
2358
2359A new API function C<sv_setvpv_bufsize()> allows simultaneously setting the
2360length and allocated size of the buffer in an C<SV>, growing the buffer if
2361necessary.
2362
2363=item *
2364
2365A new API macro C<SvPVCLEAR()> sets its C<SV> argument to an empty string,
2366like Perl-space C<$x = ''>, but with several optimisations.
2367
2368=item *
2369
2370All parts of the internals now agree that the C<sassign> op is a C<BINOP>;
2371previously it was listed as a C<BASEOP> in F<regen/opcodes>, which meant
2372that several parts of the internals had to be special-cased to accommodate
2373it. This oddity's original motivation was to handle code like C<$x ||= 1>;
2374that is now handled in a simpler way.
2375
2376=item *
2377
2378Several new internal C macros have been added that take a string literal as
2379arguments, alongside existing routines that take the equivalent value as two
2380arguments, a character pointer and a length. The advantage of this is that
2381the length of the string is calculated automatically, rather than having to
2382be done manually. These routines are now used where appropriate across the
2383entire codebase.
2384
2385=item *
2386
2387The code in F<gv.c> that determines whether a variable has a special meaning
2388to Perl has been simplified.
2389
2390=item *
2391
2392The C<DEBUGGING>-mode output for regex compilation and execution has been
2393enhanced.
2394
2395=item *
2396
2397Several macros and functions have been added to the public API for
2398dealing with Unicode and UTF-8-encoded strings. See
2399L<perlapi/Unicode Support>.
2400
2401=item *
2402
2403Use C<my_strlcat()> in C<locale.c>. While C<strcat()> is safe in this context,
2404some compilers were optimizing this to C<strcpy()> causing a porting test to
2405fail that looks for unsafe code. Rather than fighting this, we just use
2406C<my_strlcat()> instead.
2407
2408=item *
2409
2410Three new ops, C<OP_ARGELEM>, C<OP_ARGDEFELEM> and C<OP_ARGCHECK> have
2411been added. These are intended principally to implement the individual
2412elements of a subroutine signature, plus any overall checking required.
2413
2414=item *
2415
2416Perl no longer panics when switching into some locales on machines with
2417buggy C<strxfrm()> implementations in their libc. [perl #121734]
2418
2419=item *
2420
2421Perl is now built with the C<PERL_OP_PARENT> compiler define enabled by
2422default. To disable it, use the C<PERL_NO_OP_PARENT> compiler define.
2423This flag alters how the C<op_sibling> field is used in C<OP> structures,
2424and has been available optionally since perl 5.22.0.
2425
2426See L<perl5220delta/"Internal Changes"> for more details of what this
2427build option does.
2428
2429=item *
2430
2431The meanings of some internal SV flags have been changed
2432
2433OPpRUNTIME, SVpbm_VALID, SVpbm_TAIL, SvTAIL_on, SvTAIL_off, SVrepl_EVAL,
2434SvEVALED
2435
2436=item *
2437
2438Change C<hv_fetch(…, "…", …, …)> to C<hv_fetchs(…, "…", …)>
2439
2440The dual-life dists all use Devel::PPPort, so they can use this function even
2441though it was only added in 5.10.
2442
2443=back
2444
2445=head1 Selected Bug Fixes
2446
2447=over 4
2448
2449=item *
2450
2451C< $-{$name} > would leak an C<AV> on each access if the regular
2452expression had no named captures. The same applies to access to any
2453hash tied with L<Tie::Hash::NamedCapture> and C<< all =E<gt> 1 >>. [perl
2454#130822]
2455
2456=item *
2457
2458Attempting to use the deprecated variable C<$#> as the object in an
2459indirect object method call could cause a heap use after free or
2460buffer overflow. [perl #129274]
2461
2462=item *
2463
2464When checking for an indirect object method call in some rare cases
2465the parser could reallocate the line buffer but then continue to use
2466pointers to the old buffer. [perl #129190]
2467
2468=item *
2469
2470Supplying a glob as the format argument to L<perlfunc/formline> would
2471cause an assertion failure. [perl #130722]
2472
2473=item *
2474
2475Code like C< $value1 =~ qr/.../ ~~ $value2 > would have the match
2476converted into a qr// operator, leaving extra elements on the stack to
2477confuse any surrounding expression. [perl #130705]
2478
2479=item *
2480
2481Since 5.24.0 in some obscure cases, a regex which included code blocks
2482from multiple sources (e.g. via embedded via qr// objects) could end up
2483with the wrong current pad and crash or give weird results. [perl #129881]
2484
2485=item *
2486
2487Occasionally C<local()>s in a code block within a patterns weren't being
2488undone when the pattern matching backtracked over the code block.
2489[perl #126697]
2490
2491=item *
2492
2493Using C<substr()> to modify a magic variable could access freed memory
2494in some cases. [perl #129340]
2495
2496=item *
2497
2498Perl 5.25.9 was fixed so that under C<use utf8>, the entire Perl program
2499is checked that the UTF-8 is wellformed. It turns out that several edge
2500cases were missed, and are now fixed. [perl #126310] was the original
2501ticket.
2502
2503=item *
2504
2505Under C<use utf8>, the entire Perl program is now checked that the UTF-8
2506is wellformed. This resolves [perl #126310].
2507
2508=item *
2509
2510The range operator C<..> on strings now handles its arguments correctly when in
2511the scope of the L<< C<unicode_strings>|feature/"The 'unicode_strings' feature" >>
2512feature. The previous behaviour was sufficiently unexpected that we believe no
2513correct program could have made use of it.
2514
2515=item *
2516
2517The S<split> operator did not ensure enough space was allocated for
2518its return value in scalar context. It could then write a single
2519pointer immediately beyond the end of the memory block allocated for
2520the stack. [perl #130262]
2521
2522=item *
2523
2524Using a large code point with the C<W> pack template character with
2525the current output position aligned at just the right point could
2526cause a write a single zero byte immediately beyond the end of an
2527allocated buffer. [perl #129149]
2528
2529=item *
2530
2531Supplying the form picture argument as part of the form argument list
2532where the picture specifies modifying the argument could cause an
2533access to the new freed compiled form. [perl #129125]
2534
2535=item *
2536
2537Fix a problem with sort's build-in compare, where it would not sort
2538correctly with 64-bit integers, and non-long doubles. [perl #130335]
2539
2540=item *
2541
2542Fix issues with /(?{ ... E<lt>E<lt>EOF })/ that broke Method-Signatures. [perl #130398]
2543
2544=item *
2545
2546Fix a macro which caused syntax error on an EBCDIC build.
2547
2548=item *
2549
2550Prevent tests from getting hung up on 'NonStop' option. [perl #130445]
2551
2552=item *
2553
2554Fixed an assertion failure with C<chop> and C<chomp>, which
2555could be triggered by C<chop(@x =~ tr/1/1/)>. [perl #130198].
2556
2557=item *
2558
2559Fixed a comment skipping error under C</x>; it could stop skipping a
2560byte early, which could be in the middle of a UTF-8 character.
2561[perl #130495].
2562
2563=item *
2564
2565F<perldb> now ignores F</dev/tty> on non-Unix systems. [perl #113960];
2566
2567=item *
2568
2569Fix assertion failure for C<{}-E<gt>$x> when C<$x> isn't defined. [perl #130496].
2570
2571=item *
2572
2573DragonFly BSD now has support for setproctitle(). [perl #130068].
2574
2575=item *
2576
2577Fix an assertion error which could be triggered when lookahead string
2578in patterns exceeded a minimum length. [perl #130522].
2579
2580=item *
2581
2582Only warn once per literal about a misplaced C<_>. [perl #70878].
2583
2584=item *
2585
2586Ensure range-start is set after error in C<tr///>. [perl #129342].
2587
2588=item *
2589
2590Don't read past start of string for unmatched backref; otherwise,
2591we may have heap buffer overflow. [perl #129377].
2592
2593=item *
2594
2595Properly recognize mathematical digit ranges starting at U+1D7E.
2596C<use re 'strict'> is supposed to warn if you use a range whose start
2597and end digit aren't from the same group of 10. It didn't do that
2598for five groups of mathematical digits starting at U+1D7E.
2599
2600=item *
2601
2602A sub containing a "forward" declaration with the same name (e.g.,
2603C<sub c { sub c; }>) could sometimes crash or loop infinitely. [perl
2604#129090]
2605
2606=item *
2607
2608A crash in executing a regex with a floating UTF-8 substring against a
2609target string that also used UTF-8 has been fixed. [perl #129350]
2610
2611=item *
2612
2613Previously, a shebang line like C<#!perl -i u> could be erroneously
2614interpreted as requesting the C<-u> option. This has been fixed. [perl
2615#129336]
2616
2617=item *
2618
2619The regex engine was previously producing incorrect results in some rare
2620situations when backtracking past a trie that matches only one thing; this
2621showed up as capture buffers (C<$1>, C<$2>, etc) erroneously containing data
2622from regex execution paths that weren't actually executed for the final
2623match. [perl #129897]
2624
2625=item *
2626
2627Certain regexes making use of the experimental C<regex_sets> feature could
2628trigger an assertion failure. This has been fixed. [perl #129322]
2629
2630=item *
2631
2632Invalid assignments to a reference constructor (e.g., C<\eval=time>) could
2633sometimes crash in addition to giving a syntax error. [perl #125679]
2634
2635=item *
2636
2637The parser could sometimes crash if a bareword came after C<evalbytes>.
2638[perl #129196]
2639
2640=item *
2641
2642Autoloading via a method call would warn erroneously ("Use of inherited
2643AUTOLOAD for non-method") if there was a stub present in the package into
2644which the invocant had been blessed. The warning is no longer emitted in
2645such circumstances. [perl #47047]
2646
2647=item *
2648
2649A sub containing with a "forward" declaration with the same name (e.g.,
2650C<sub c { sub c; }>) could sometimes crash or loop infinitely. [perl
2651#129090]
2652
2653=item *
2654
2655The use of C<splice> on arrays with nonexistent elements could cause other
2656operators to crash. [perl #129164]
2657
2658=item *
2659
2660Fixed case where C<re_untuit_start> will overshoot the length of a utf8
2661string. [perl #129012]
2662
2663=item *
2664
2665Handle C<CXt_SUBST> better in C<Perl_deb_stack_all>, previously it wasn't
2666checking that the I<current> C<cx> is the right type, and instead was always
2667checking the base C<cx> (effectively a noop). [perl #129029]
2668
2669=item *
2670
2671Fixed two possible use-after-free bugs in C<Perl_yylex>. C<Perl_yylex>
2672maintains up to two pointers into the parser buffer, one of which can
2673become stale under the right conditions. [perl #129069]
2674
2675=item *
2676
2677Fixed a crash with C<s///l> where it thought it was dealing with UTF-8
2678when it wasn't. [perl #129038]
2679
2680=item *
2681
2682Fixed place where regex was not setting the syntax error correctly.
2683[perl #129122]
2684
2685=item *
2686
2687The C<&.> operator (and the C<&> operator, when it treats its arguments as
2688strings) were failing to append a trailing null byte if at least one string
2689was marked as utf8 internally. Many code paths (system calls, regexp
2690compilation) still expect there to be a null byte in the string buffer
2691just past the end of the logical string. An assertion failure was the
2692result. [perl #129287]
2693
2694=item *
2695
2696Check C<pack_sockaddr_un()>'s return value because C<pack_sockaddr_un()>
2697silently truncates the supplied path if it won't fit into the C<sun_path>
2698member of C<sockaddr_un>. This may change in the future, but for now
2699check the path in theC<sockaddr> matches the desired path, and skip if
2700it doesn't. [perl #128095]
2701
2702=item *
2703
2704Make sure C<PL_oldoldbufptr> is preserved in C<scan_heredoc()>. In some
2705cases this is used in building error messages. [perl #128988]
2706
2707=item *
2708
2709Check for null PL_curcop in IN_LC() [perl #129106]
2710
2711=item *
2712
2713Fixed the parser error handling for an 'C<:attr(foo>' that does not have
2714an ending 'C<)>'.
2715
2716=item *
2717
2718Fix C<Perl_delimcpy()> to handle a backslash as last char, this
2719actually fixed two bugs, [perl #129064] and [perl #129176].
2720
2721=item *
2722
2723[perl #129267] rework gv_fetchmethod_pvn_flags separator parsing to
2724prevent possible string overrun with invalid len in gv.c
2725
2726=item *
2727
2728Problems with in-place array sorts: code like C<@a = sort { ... } @a>,
2729where the source and destination of the sort are the same plain array, are
2730optimised to do less copying around. Two side-effects of this optimisation
2731were that the contents of C<@a> as visible to to sort routine were
2732partially sorted, and under some circumstances accessing C<@a> during the
2733sort could crash the interpreter. Both these issues have been fixed, and
2734Sort functions see the original value of C<@a>.
2735
2736=item *
2737
2738Non-ASCII string delimiters are now reported correctly in error messages
2739for unterminated strings. [perl #128701]
2740
2741=item *
2742
2743C<pack("p", ...)> used to emit its warning ("Attempt to pack pointer to
2744temporary value") erroneously in some cases, but has been fixed.
2745
2746=item *
2747
2748C<@DB::args> is now exempt from "used once" warnings. The warnings only
2749occurred under B<-w>, because F<warnings.pm> itself uses C<@DB::args>
2750multiple times.
2751
2752=item *
2753
2754The use of built-in arrays or hash slices in a double-quoted string no
2755longer issues a warning ("Possible unintended interpolation...") if the
2756variable has not been mentioned before. This affected code like
2757C<qq|@DB::args|> and C<qq|@SIG{'CHLD', 'HUP'}|>. (The special variables
2758C<@-> and C<@+> were already exempt from the warning.)
2759
2760=item *
2761
2762C<gethostent> and similar functions now perform a null check internally, to
2763avoid crashing with torsocks. This was a regression from 5.22. [perl
2764#128740]
2765
2766=item *
2767
2768C<defined *{'!'}>, C<defined *{'['}>, and C<defined *{'-'}> no longer leak
2769memory if the typeglob in question has never been accessed before.
2770
2771=item *
2772
2c8edc25
S
2773Mentioning the same constant twice in a row (which is a syntax error) no
2774longer fails an assertion under debugging builds. This was a regression
2775from 5.20. [perl #126482]
2776
2777=item *
2778
2779Many issues relating to C<printf "%a"> of hexadecimal floating point
2780were fixed. In addition, the "subnormals" (formerly known as "denormals")
2781floating point anumbers are now supported both with the plain IEEE 754
2782floating point numbers (64-bit or 128-bit) and the x86 80-bit
2783"extended precision". Note that subnormal hexadecimal floating
2784point literals will give a warning about "exponent underflow".
2785[perl #128843, #128889, #128890, #128893, #128909, #128919]
2786
2787=item *
2788
2789A regression in 5.24 with C<tr/\N{U+...}/foo/> when the code point was between
2790128 and 255 has been fixed. [perl #128734].
2791
2792=item *
2793
2794A regression from the previous development release, 5.23.3, where
2795compiling a regular expression could crash the interpreter has been
2796fixed. [perl #128686].
2797
2798=item *
2799
2800Use of a string delimiter whose code point is above 2**31 now works
2801correctly on platforms that allow this. Previously, certain characters,
2802due to truncation, would be confused with other delimiter characters
2803with special meaning (such as C<?> in C<m?...?>), resulting
2804in inconsistent behaviour. Note that this is non-portable,
2805and is based on Perl's extension to UTF-8, and is probably not
2806displayable nor enterable by any editor. [perl #128738]
2807
2808=item *
2809
2810C<@{x> followed by a newline where C<x> represents a control or non-ASCII
2811character no longer produces a garbled syntax error message or a crash.
2812[perl #128951]
2813
2814=item *
2815
2816An assertion failure with C<%: = 0> has been fixed.
2817L<[perl #128238]|https://rt.perl.org/Public/Bug/Display.html?id=128238>
2818
2819=item *
2820
2821In Perl 5.18, the parsing of C<"$foo::$bar"> was accidentally changed, such
2822that it would be treated as C<$foo."::".$bar>. The previous behavior, which
2823was to parse it as C<$foo:: . $bar>, has been restored.
2824L<[perl #128478]|https://rt.perl.org/Public/Bug/Display.html?id=128478>
2825
2826=item *
2827
2828Since Perl 5.20, line numbers have been off by one when perl is invoked with
2829the B<-x> switch. This has been fixed.
2830L<[perl #128508]|https://rt.perl.org/Public/Bug/Display.html?id=128508>
2831
2832=item *
2833
2834Vivifying a subroutine stub in a deleted stash (e.g., C<delete $My::{"Foo::"};
2835\&My::Foo::foo>) no longer crashes. It had begun crashing in Perl 5.18.
2836L<[perl #128532]|https://rt.perl.org/Public/Bug/Display.html?id=128532>
2837
2838=item *
2839
2840Some obscure cases of subroutines and file handles being freed at the same time
2841could result in crashes, but have been fixed. The crash was introduced in Perl
28425.22.
2843L<[perl #128597]|https://rt.perl.org/Public/Bug/Display.html?id=128597>
2844
2845=item *
2846
2847Code that looks for a variable name associated with an uninitialized value
2848could cause an assertion in cases where magic is involved, such as
2849C<$ISA[0][0]>. This has now been fixed.
2850L<[perl #128253]|https://rt.perl.org/Public/Bug/Display.html?id=128253>
2851
2852=item *
2853
2854A crash caused by code generating the warning "Subroutine STASH::NAME
2855redefined" in cases such as C<sub P::f{} undef *P::; *P::f =sub{};> has been
2856fixed. In these cases, where the STASH is missing, the warning will now appear
2857as "Subroutine NAME redefined".
2858L<[perl #128257]|https://rt.perl.org/Public/Bug/Display.html?id=128257>
2859
2860=item *
2861
2862Fixed an assertion triggered by some code that handles deprecated behavior in
2863formats, e.g. in cases like this:
2864
2865 format STDOUT =
2866 @
2867 0"$x"
2868
2869L<[perl #128255]|https://rt.perl.org/Public/Bug/Display.html?id=128255>
2870
2871=item *
2872
2873A possible divide by zero in string transformation code on Windows has been
2874avoided, fixing a crash when collating an empty string.
2875L<[perl #128618]|https://rt.perl.org/Public/Bug/Display.html?id=128618>
2876
2877=item *
2878
2879Some regular expression parsing glitches could lead to assertion failures with
e6abae1c 2880regular expressions such as C</(?E<lt>=/> and C</(?E<lt>!/>. This has now been fixed.
2c8edc25
S
2881L<[perl #128170]|https://rt.perl.org/Public/Bug/Display.html?id=128170>
2882
2883=item *
2884
2885C< until ($x = 1) { ... } > and C< ... until $x = 1 > now properly
2886warn when syntax warnings are enabled. [perl #127333]
2887
2888=item *
2889
2890socket() now leaves the error code returned by the system in C<$!> on
2891failure. [perl #128316]
2892
2893=item *
2894
2895Assignment variants of any bitwise ops under the C<bitwise> feature would
2896crash if the left-hand side was an array or hash. [perl #128204]
2897
2898=item *
2899
2900C<require> followed by a single colon (as in C<foo() ? require : ...> is
2901now parsed correctly as C<require> with implicit $_, rather than
2902C<require "">. [perl #128307]
2903
2904=item *
2905
2906Scalar C<keys %hash> can now be assigned to consistently in all scalar
2907lvalue contexts. Previously it worked for some contexts but not others.
2908
2909=item *
2910
2911List assignment to C<vec> or C<substr> with an array or hash for its first
2912argument used to result in crashes or "Can't coerce" error messages at run
2913time, unlike scalar assignment, which would give an error at compile time.
2914List assignment now gives a compile-time error, too. [perl #128260]
2915
2916=item *
2917
2918Expressions containing an C<&&> or C<||> operator (or their synonyms C<and>
2919and C<or>) were being compiled incorrectly in some cases. If the left-hand
2920side consisted of either a negated bareword constant or a negated C<do {}>
2921block containing a constant expression, and the right-hand side consisted of
2922a negated non-foldable expression, one of the negations was effectively
2923ignored. The same was true of C<if> and C<unless> statement modifiers,
2924though with the left-hand and right-hand sides swapped. This long-standing
2925bug has now been fixed. [perl #127952]
2926
2927=item *
2928
2929C<reset> with an argument no longer crashes when encountering stash entries
2930other than globs. [perl #128106]
2931
2932=item *
2933
2934Assignment of hashes to, and deletion of, typeglobs named C<*::::::> no
2935longer causes crashes. [perl #128086]
2936
2937=item *
2938
2939Handle SvIMMORTALs in LHS of list assign. [perl #129991]
2940
2941=item *
2942
2943[perl #130010] a5540cf breaks texinfo
2944
2945This involved user-defined Unicode properties.
2946
2947=item *
2948
2949Fix error message for unclosed C<\N{> in regcomp.
2950
2951An unclosed C<\N{> could give the wrong error message
2952C<"\N{NAME} must be resolved by the lexer">.
2953
2954=item *
2955
2956List assignment in list context where the LHS contained aggregates and
2957where there were not enough RHS elements, used to skip scalar lvalues.
2958Previously, C<(($a,$b,@c,$d) = (1))> in list context returned C<($a)>; now
2959it returns C<($a,$b,$d)>. C<(($a,$b,$c) = (1))> is unchanged: it still
2960returns C<($a,$b,$c)>. This can be seen in the following:
2961
2962 sub inc { $_++ for @_ }
2963 inc(($a,$b,@c,$d) = (10))
2964
2965Formerly, the values of C<($a,$b,$d)> would be left as C<(11,undef,undef)>;
2966now they are C<(11,1,1)>.
2967
2968=item *
2969
2970[perl 129903]
2971
2972The basic problem is that code like this: /(?{ s!!! })/ can trigger infinite
2973recursion on the C stack (not the normal perl stack) when the last successful
2974pattern in scope is itself. Since the C stack overflows this manifests as an
2975untrappable error/segfault, which then kills perl.
2976
2977We avoid the segfault by simply forbidding the use of the empty pattern when it
2978would resolve to the currently executing pattern.
2979
2980=item *
2981
2982[perl 128997] Avoid reading beyond the end of the line buffer when there's a
2983short UTF-8 character at the end.
2984
2985=item *
2986
2987[perl 129950] fix firstchar bitmap under utf8 with prefix optimisation.
2988
2989=item *
2990
2991[perl 129954] Carp/t/arg_string.t: be liberal in f/p formats.
2992
2993=item *
2994
2995[perl 129928] make do "a\0b" fail silently instead of throwing.
2996
2997=item *
2998
2999[perl 129130] make chdir allocate the stack it needs.
3000
3001=back
3002
3003=head1 Known Problems
3004
3005=over 4
3006
3007=item *
3008
3009Some modules have been broken by the L<context stack rework|/Internal Changes>.
3010These modules were relying on non-guaranteed implementation details in perl.
3011Their maintainers have been informed, and should contact perl5-porters for
3012advice if needed. Below is a subset of these modules:
3013
3014=over 4
3015
3016=item * L<Algorithm::Permute>
3017
3018=item * L<Coro>
3019
3020L<Coro> and perl v5.22.0 were already incompatible due to a change in the perl,
3021and the reworking on the perl context stack creates a further incompatibility.
3022perl5-porters has L<discussed the issue on the mailing
3023list|http://www.nntp.perl.org/group/perl.perl5.porters/2016/05/msg236174.html>.
3024
3025=item * L<Data::Alias>
3026
3027=item * L<RPerl>
3028
3029=item * L<Scope::Upper>
3030
3031=item * L<TryCatch>
3032
3033=back
3034
3035=item *
3036
3037The module L<lexical::underscore> no longer works on perl v5.24.0, because perl
3038no longer has a lexical C<$_>!
3039
3040=item *
3041
3042C<mod_perl> has been patched for compatibility for v5.22.0 and later but no
3043release has been made. The relevant patch (and other changes) can be found in
3044their source code repository, L<mirrored at
3045GitHub|https://github.com/apache/mod_perl/commit/82827132efd3c2e25cc413c85af61bb63375da6e>.
3046
3047=back
3048
3049=head1 Errata From Previous Releases
3050
3051=over 4
3052
3053=item *
3054
3055Parsing bad POSIX charclasses no longer leaks memory. This was fixed in Perl
30565.25.2
3057L<[perl #128313]|https://rt.perl.org/Public/Bug/Display.html?id=128313>
3058
3059=item *
3060
3061Fixed issues with recursive regexes. The behavior was fixed in Perl 5.24.0.
3062L<[perl #126182]|https://rt.perl.org/Public/Bug/Display.html?id=126182>
3063
3064=back
3065
3066=head1 Obituary
3067
3068Jon Portnoy (AVENJ), a prolific Perl author and admired Gentoo community
3069member, has passed away on August 10, 2016. He will be remembered and
3070missed by all those with which he came in contact and enriched with his
3071intellect, wit, and spirit.
3072
3073It is with great sadness we also note Kip Hampton's passing.. Probably
3074best known as the author of the Perl & XML column on XML.com, he was a
3075core contributor to AxKit, an XML server platform that became an Apache
3076Foundation project. He was a frequent speaker in the early days at
3077OSCON, and most recently at YAPC::NA in Madison. He was frequently on
3078irc.perl.org as `ubu`, generally in the #axkit-dahut community, the
3079group responsible for YAPC::NA Asheville in 2011.
a049258c 3080
2c8edc25
S
3081Kip and his constant contributions to the community will be greatly
3082missed.
a049258c
S
3083
3084=head1 Acknowledgements
2e0dcc12 3085
0cc8c746 3086Perl 5.26.0 represents approximately 12 months of development since Perl 5.24.0
c2948ced 3087and contains approximately 370,000 lines of changes across 2,600 files from 86
0cc8c746
S
3088authors.
3089
3090Excluding auto-generated files, documentation and release tools, there were
3091approximately 230,000 lines of changes to 1,800 .pm, .t, .c and .h files.
3092
3093Perl continues to flourish into its third decade thanks to a vibrant community
3094of users and developers. The following people are known to have contributed the
3095improvements that became Perl 5.24.1:
3096
3097Aaron Crane, Abigail, Ævar Arnfjörð Bjarmason, Alex Vandiver, Andreas
3098König, Andreas Voegele, Andrew Fresh, Andy Lester, Aristotle Pagaltzis, Chad
3099Granum, Chase Whitener, Chris 'BinGOs' Williams, Chris Lamb, Christian Hansen,
3100Christian Millour, Colin Newell, Craig A. Berry, Dagfinn Ilmari Mannsåker, Dan
c2948ced
S
3101Collins, Daniel Dragan, Dave Cross, Dave Rolsky, David Golden, David H.
3102Gutteridge, David Mitchell, Dominic Hargreaves, Doug Bell, E. Choroba, Ed Avis,
3103Father Chrysostomos, François Perrad, Hauke D, H.Merijn Brand, Hugo van der
3104Sanden, Ivan Pozdeev, James E Keenan, James Raspass, Jarkko Hietaniemi, Jerry
3105D. Hedden, Jim Cromie, J. Nick Koston, John Lightsey, Karen Etheridge, Karl
3106Williamson, Leon Timmermans, Lukas Mai, Matthew Horsfall, Maxwell Carey, Misty
3107De Meo, Neil Bowers, Nicholas Clark, Nicolas R., Niko Tyni, Pali, Paul
3108Marquess, Peter Avalos, Petr Písař, Pino Toscano, Rafael Garcia-Suarez, Reini
3109Urban, Renee Baecker, Ricardo Signes, Richard Levitte, Rick Delaney, Salvador
3110Fandiño, Samuel Thibault, Sawyer X, Sébastien Aperghis-Tramoni, Sergey
3111Aleynikov, Shlomi Fish, Smylers, Stefan Seifert, Steffen Müller, Stevan
3112Little, Steve Hay, Steven Humphrey, Sullivan Beck, Theo Buehler, Thomas Sibley,
3113Todd Rinaldo, Tomasz Konojacki, Tony Cook, Unicode Consortium, Yaroslav Kuzmin,
3114Yves Orton, Zefram.
0cc8c746
S
3115
3116The list above is almost certainly incomplete as it is automatically generated
3117from version control history. In particular, it does not include the names of
3118the (very much appreciated) contributors who reported issues to the Perl bug
3119tracker.
3120
3121Many of the changes included in this version originated in the CPAN modules
3122included in Perl's core. We're grateful to the entire CPAN community for
3123helping Perl to flourish.
3124
3125For a more complete list of all of Perl's historical contributors, please see
3126the F<AUTHORS> file in the Perl source distribution.
f5b73711 3127
44691e6f
AB
3128=head1 Reporting Bugs
3129
2c8edc25
S
3130If you find what you think is a bug, you might check the articles recently
3131posted to the comp.lang.perl.misc newsgroup and the perl bug database at
3132L<https://rt.perl.org/> . There may also be information at
4b8803f0 3133L<http://www.perl.org/> , the Perl Home Page.
44691e6f 3134
e08634c5
SH
3135If you believe you have an unreported bug, please run the L<perlbug> program
3136included with your release. Be sure to trim your bug down to a tiny but
3137sufficient test case. Your bug report, along with the output of C<perl -V>,
3138will be sent off to perlbug@perl.org to be analysed by the Perl porting team.
44691e6f 3139
87c118b9
DM
3140If the bug you are reporting has security implications which make it
3141inappropriate to send to a publicly archived mailing list, then see
c0ea3294
SH
3142L<perlsec/SECURITY VULNERABILITY CONTACT INFORMATION>
3143for details of how to report the issue.
44691e6f
AB
3144
3145=head1 SEE ALSO
3146
e08634c5
SH
3147The F<Changes> file for an explanation of how to view exhaustive details on
3148what changed.
44691e6f
AB
3149
3150The F<INSTALL> file for how to build Perl.
3151
3152The F<README> file for general stuff.
3153
3154The F<Artistic> and F<Copying> files for copyright information.
3155
3156=cut