5 perl5252delta - what is new for perl v5.25.2
9 This document describes differences between the 5.25.1 release and the 5.25.2
12 If you are upgrading from an earlier release such as 5.25.0, first read
13 L<perl5251delta>, which describes differences between 5.25.0 and 5.25.1.
15 =head1 Core Enhancements
17 =head2 Perl can now do default collation in UTF-8 locales on platforms
20 Some platforms natively do a reasonable job of collating and sorting in
21 UTF-8 locales. Perl now works with those. For portability and full
22 control, L<Unicode::Collate> is still recommended, but now you may
23 not need to do anything special to get good-enough results, depending on
25 L<perllocale/Category C<LC_COLLATE>: Collation: Text Comparisons and Sorting>.
27 =head2 Better locale collation of strings containing embedded C<NUL>
30 In locales that have multi-level character weights, these are now
31 ignored at the higher priority ones. There are still some gotchas in
32 some strings, though. See
33 L<perllocale/Collation of strings containing embedded C<NUL> characters>.
35 =head2 Lexical subroutines are no longer experimental
37 Using the C<lexical_subs> feature no longer emits a warning. Existing code that disables the C<experimental::lexical_subs> warning category that the
38 feature previously used will continue to work. The C<lexical_subs> feature
39 has no effect; all Perl code can use lexical subroutines, regardless of
40 what feature declarations are in scope.
42 =head2 C<CORE> subroutines for hash and array functions callable via
45 The hash and array functions in the C<CORE> namespace--C<keys>, C<each>,
46 C<values>, C<push>, C<pop>, C<shift>, C<unshift> and C<splice>--, can now
47 be called with ampersand syntax (C<&CORE::keys(\%hash>) and via reference
48 (C<< my $k = \&CORE::keys; $k->(\%hash) >>). Previously they could only be
53 =head2 C<-Di> switch is now required for PerlIO debugging output
55 Previously PerlIO debugging output would be sent to the file specified
56 by the C<PERLIO_DEBUG> environment variable if perl wasn't running
57 setuid and the C<-T> or C<-t> switches hadn't been parsed yet.
59 If perl performed output at a point where it hadn't yet parsed its
60 switches this could result in perl creating or overwriting the file
61 named by C<PERLIO_DEBUG> even when the C<-T> switch had been supplied.
63 Perl now requires the C<-Di> switch to produce PerlIO debugging
64 output. By default this is written to C<stderr>, but can optionally
65 be redirected to a file by setting the C<PERLIO_DEBUG> environment
68 If perl is running setuid or the C<-T> switch has supplied
69 C<PERLIO_DEBUG> is ignored and the debugging output is sent to
70 C<stderr> as for any other C<-D> switch.
72 =head1 Incompatible Changes
74 =head2 C<keys> returned from an lvalue subroutine
76 C<keys> returned from an lvalue subroutine can no longer be assigned
79 sub foo : lvalue { keys(%INC) }
81 sub bar : lvalue { keys(@_) }
82 (bar) = 3; # also an error
84 This makes the lvalue sub case consistent with C<(keys %hash) = ...> and
85 C<(keys @_) = ...>, which are also errors. [perl #128187]
87 =head1 Modules and Pragmata
89 =head2 Updated Modules and Pragmata
95 L<CPAN> has been upgraded from version 2.11 to 2.14.
99 L<Devel::Peek> has been upgraded from version 1.23 to 1.24.
103 L<diagnostics> has been upgraded from version 1.34 to 1.35.
107 L<DynaLoader> has been upgraded from version 1.38 to 1.39.
111 L<ExtUtils::MakeMaker> has been upgraded from version 7.10_01 to 7.18.
115 L<ExtUtils::Miniperl> has been upgraded from version 1.05 to 1.06.
119 L<ExtUtils::ParseXS> has been upgraded from version 3.31 to 3.32.
123 L<ExtUtils::Typemaps> has been upgraded from version 3.31 to 3.32.
127 L<feature> has been upgraded from version 1.43 to 1.44.
131 L<File::Copy> has been upgraded from version 2.31 to 2.32.
135 L<File::Glob> has been upgraded from version 1.26 to 1.27.
139 L<File::Spec> has been upgraded from version 3.63 to 3.64.
143 L<FileHandle> has been upgraded from version 2.02 to 2.03.
147 L<Getopt::Long> has been upgraded from version 2.48 to 2.49.
151 L<HTTP::Tiny> has been upgraded from version 0.056 to 0.058.
155 L<JSON::PP> has been upgraded from version 2.27300 to 2.27400.
159 L<Locale::Codes> has been upgraded from version 3.38 to 3.39.
163 L<Module::CoreList> has been upgraded from 5.20160520 to 5.20160620.
167 L<Opcode> has been upgraded from version 1.34 to 1.35.
171 L<Pod::Checker> has been upgraded from version 1.60 to 1.73.
175 L<Pod::Functions> has been upgraded from version 1.10 to 1.11.
179 L<Pod::Usage> has been upgraded from version 1.68 to 1.69.
183 L<POSIX> has been upgraded from version 1.69 to 1.70.
187 L<Test::Simple> has been upgraded from version 1.302015 to 1.302026.
191 L<Thread::Queue> has been upgraded from version 3.09 to 3.11.
195 L<threads> has been upgraded from version 2.08 to 2.09.
199 L<Time::HiRes> has been upgraded from version 1.9733 to 1.9734.
203 L<Unicode::UCD> has been upgraded from version 0.64 to 0.65.
207 L<VMS::DCLsym> has been upgraded from version 1.06 to 1.07.
213 =head2 Changes to Existing Documentation
215 =head3 L<perlcommunity>
221 All references to Usenet have been removed.
231 All references to Usenet have been removed.
241 Document NUL collation handling.
245 =head3 L<perlmodinstall>
251 All references to Usenet have been removed.
261 Updated the mirror list.
265 All references to Usenet have been removed.
275 All references to Usenet have been removed.
281 The following additions or changes have been made to diagnostic output,
282 including warnings and fatal error messages. For the complete list of
283 diagnostic messages, see L<perldiag>.
285 =head2 New Diagnostics
293 L<Version control conflict marker|perldiag/"Version control conflict marker">
295 (F) The parser found a line starting with C<E<lt><<<<<<>,
296 C<E<gt>E<gt>E<gt>E<gt>E<gt>E<gt>E<gt>>, or C<=======>. These may be left by a
297 version control system to mark conflicts after a failed merge operation.
301 L<%s: command not found|perldiag/"%s: command not found">
303 (A) You've accidentally run your script through B<bash> or another shell
304 instead of Perl. Check the #! line, or manually feed your script into
305 Perl yourself. The #! line at the top of your file could look like:
311 L<%s: command not found: %s|perldiag/"%s: command not found: %s">
313 (A) You've accidentally run your script through B<zsh> or another shell
314 instead of Perl. Check the #! line, or manually feed your script into
315 Perl yourself. The #! line at the top of your file could look like:
321 L<Unescaped left brace in regex is deprecated here, passed through in regex; marked by S<<-- HERE> in mE<sol>%sE<sol>|perldiag/"Unescaped left brace in regex is deprecated here, passed through in regex; marked by S<<-- HERE> in m/%s/">
323 Unescaped left braces are already illegal in some contexts in regular
324 expression patterns, but, due to an oversight, no deprecation warning
325 was raised in other contexts where they are intended to become illegal.
326 This warning is now raised in these contexts.
330 =head2 Changes to Existing Diagnostics
336 L<Unescaped left brace in regex is illegal here in regex; marked by S<<-- HERE> in mE<sol>%sE<sol>|perldiag/"Unescaped left brace in regex is illegal here in regex; marked by S<<-- HERE> in m/%s/">
338 The word "here" has been added to the message that was raised in
339 v5.25.1. This is to indicate that there are contexts in which unescaped
340 left braces are not (yet) illegal.
344 =head1 Configuration and Compilation
350 F<make_ext.pl> no longer updates a module's F<pm_to_blib> file when no
351 files require updates. This could cause dependencies, F<perlmain.c>
352 in particular, to be rebuilt unnecessarily. [perl #126710]
356 The output of C<perl -V> has been reformatted so that each configuration
357 and compile-time option is now listed one per line, to improve
368 F<t/harness> now tries really hard not to run tests outside of the Perl
369 source tree. [perl #124050]
373 =head1 Internal Changes
379 Perl no longer panics when switching into some locales on machines with
380 buggy C<strxfrm()> implementations in their libc. [perl #121734]
384 =head1 Selected Bug Fixes
390 C< until ($x = 1) { ... } > and C< ... until $x = 1 > now properly
391 warn when syntax warnings are enabled. [perl #127333]
395 socket() now leaves the error code returned by the system in C<$!> on
396 failure. [perl #128316]
400 Assignment variants of any bitwise ops under the C<bitwise> feature would
401 crash if the left-hand side was an array or hash. [perl #128204]
405 C<require> followed by a single colon (as in C<foo() ? require : ...> is
406 now parsed correctly as C<require> with implicit $_, rather than
407 C<require "">. [perl #128307]
411 Scalar C<keys %hash> can now be assigned to consistently in all scalar
412 lvalue contexts. Previously it worked for some contexts but not others.
416 List assignment to C<vec> or C<substr> with an array or hash for its first
417 argument used to result in crashes or "Can't coerce" error messages at run
418 time, unlike scalar assignment, which would give an error at compile time.
419 List assignment now gives a compile-time error, too. [perl #128260]
423 =head1 Acknowledgements
425 Perl 5.25.2 represents approximately 4 weeks of development since Perl 5.25.1
426 and contains approximately 32,000 lines of changes across 430 files from 28
429 Excluding auto-generated files, documentation and release tools, there were
430 approximately 27,000 lines of changes to 300 .pm, .t, .c and .h files.
432 Perl continues to flourish into its third decade thanks to a vibrant community
433 of users and developers. The following people are known to have contributed the
434 improvements that became Perl 5.25.2:
436 Aaron Crane, Andreas König, Andy Lester, Chad Granum, Chase Whitener, Chris
437 'BinGOs' Williams, Craig A. Berry, Dagfinn Ilmari Mannsåker, Dan Collins,
438 David Mitchell, Dominic Hargreaves, Ed Avis, Father Chrysostomos, H.Merijn
439 Brand, Ivan Pozdeev, James E Keenan, Jarkko Hietaniemi, Jerry D. Hedden, Jim
440 Cromie, Karl Williamson, Lukas Mai, Matthew Horsfall, Misty De Meo, Samuel
441 Thibault, Sawyer X, Sullivan Beck, Tony Cook, Yves Orton.
443 The list above is almost certainly incomplete as it is automatically generated
444 from version control history. In particular, it does not include the names of
445 the (very much appreciated) contributors who reported issues to the Perl bug
448 Many of the changes included in this version originated in the CPAN modules
449 included in Perl's core. We're grateful to the entire CPAN community for
450 helping Perl to flourish.
452 For a more complete list of all of Perl's historical contributors, please see
453 the F<AUTHORS> file in the Perl source distribution.
455 =head1 Reporting Bugs
457 If you find what you think is a bug, you might check the perl bug database
458 at L<https://rt.perl.org/> . There may also be information at
459 L<http://www.perl.org/> , the Perl Home Page.
461 If you believe you have an unreported bug, please run the L<perlbug> program
462 included with your release. Be sure to trim your bug down to a tiny but
463 sufficient test case. Your bug report, along with the output of C<perl -V>,
464 will be sent off to perlbug@perl.org to be analysed by the Perl porting team.
466 If the bug you are reporting has security implications which make it
467 inappropriate to send to a publicly archived mailing list, then see
468 L<perlsec/SECURITY VULNERABILITY CONTACT INFORMATION>
469 for details of how to report the issue.
473 The F<Changes> file for an explanation of how to view exhaustive details on
476 The F<INSTALL> file for how to build Perl.
478 The F<README> file for general stuff.
480 The F<Artistic> and F<Copying> files for copyright information.