=head1 NAME
-perldelta - what is new for perl v5.17.7
+perldelta - what is new for perl v5.17.11
=head1 DESCRIPTION
-This document describes differences between the 5.17.6 release and the 5.17.7
+This document describes differences between the 5.17.10 release and the 5.17.11
release.
-If you are upgrading from an earlier release such as 5.17.5, first read
-L<perl5176delta>, which describes differences between 5.17.5 and 5.17.6.
-
-=head1 Core Enhancements
-
-=head2 $&, $` and $' are no longer slow
-
-These three infamous variables have been redeemed and no longer slow down
-your program when used. Hence, the /p regular expression flag now does
-nothing.
-
-=head1 Security
-
-=head2 C<Storable> security warning in documentation
-
-The documentation for C<Storable> now includes a section which warns readers
-of the danger of accepting Storable documents from untrusted sources. The
-short version is that deserializing certain types of data can lead to loading
-modules and other code execution. This is documented behavior and wanted
-behavior, but this opens an attack vector for malicious entities.
-
-=head2 C<Locale::Maketext> allowed code injection via a malicious template
-
-If users could provide a translation string to Locale::Maketext, this could be
-used to invoke arbitrary Perl subroutines available in the current process.
-
-This has been fixed, but it is still possible to invoke any method provided by
-C<Locale::Maketext> itself or a subclass that you are using. One of these
-methods in turn will invoke the Perl core's C<sprintf> subroutine.
-
-In summary, allowing users to provide translation strings without auditing
-them is a bad idea.
-
-This vulnerability is documented in CVE-2012-6329.
+If you are upgrading from an earlier release such as 5.17.9, first read
+L<perl51710delta>, which describes differences between 5.17.9 and 5.17.10.
=head1 Incompatible Changes
-=head2 readline() with C<$/ = \N> now reads N characters, not N bytes
-
-Previously, when reading from a stream with I/O layers such as
-C<encoding>, the readline() function, otherwise known as the C<< <> >>
-operator, would read I<N> bytes from the top-most layer. [perl #79960]
-
-Now, I<N> characters are read instead.
-
-There is no change in behaviour when reading from streams with no
-extra layers, since bytes map exactly to characters.
-
-=head2 Lexical subroutine warnings have moved
+Although no major incompatibilities have been introduced, the "switch" family
+of features have been marked experimental and will now emit warnings. These
+are: the C<~~> operator, C<given>, and C<when>.
-The warning about the use of an experimental feature emitted when lexical
-subroutines (added in 5.17.4) are used now happens when the subroutine
-itself is declared, not when the "lexical_subs" feature is activated via
-C<use feature>.
-
-This stops C<use feature ':all'> from warning, but causes
-C<my sub foo; my sub bar> to warn twice.
-
-=head2 Overridden C<glob> is now passed one argument
-
-C<glob> overrides used to be passed a magical undocumented second argument
-that identified the caller. Nothing on CPAN was using this, and it got in
-the way of a bug fix, so it was removed. If you really need to identify
-the caller, see L<Devel::Callsite> on CPAN.
-
-=head1 Deprecations
-
-=head2 Lexical $_ is now deprecated
+=head1 Modules and Pragmata
-Since it was introduced in Perl 5.10, it has caused much confusion with no
-obvious solution:
+=head2 Updated Modules and Pragmata
-=over
+=over 4
=item *
-Various modules (e.g., List::Util) expect callback routines to use the
-global $_. C<use List::Util 'first'; my $_; first { $_ == 1 } @list> does
-not work as one would expect.
+Fixed the merge of ExtUtils-MakeMaker 6.65_01 to remove an excluded
+file. This was causing a test failure on Win32 [perl #117477]
=item *
-A C<my $_> declaration earlier in the same file can cause confusing closure
-warnings.
+B::Deparse has been upgraded from version 1.19 to 1.20, adding stub deparsing
+for lexical subroutines.
=item *
-The "_" subroutine prototype character allows called subroutines to access
-your lexical $_, so it is not really private after all.
+bigint has been upgraded from version 0.33 to 0.34.
=item *
-Nevertheless, subroutines with a "(@)" prototype and methods cannot access
-the caller's lexical $_, unless they are written in XS.
+CPAN has been upgraded from its trial 2.00 release to its final 2.00 release.
=item *
-But even XS routines cannot access a lexical $_ declared, not in the
-calling subroutine, but in an outer scope, iff that subroutine happened not
-to mention $_ or use any operators that default to $_.
-
-=back
-
-=head2 Various XS-callable functions are now deprecated
-
-The following functions will be removed from a future version of Perl,
-and should not be used. With participating C compilers (e.g., gcc),
-compiling any file that uses any of these will generate a warning.
-These were not intended for public use; there are equivalent, faster,
-macros for most of them. See L<perlapi/Character classes>:
-C<is_uni_ascii>, C<is_uni_ascii_lc>, C<is_uni_blank>, C<is_uni_blank_lc>,
-C<is_uni_cntrl>, C<is_uni_cntrl_lc>, C<is_uni_idfirst_lc>, C<is_uni_space>,
-C<is_uni_space_lc>, C<is_uni_xdigit>, C<is_uni_xdigit_lc>, C<is_utf8_ascii>,
-C<is_utf8_blank>, C<is_utf8_cntrl>, C<is_utf8_idcont>, C<is_utf8_idfirst>,
-C<is_utf8_perl_space>, C<is_utf8_perl_word>, C<is_utf8_posix_digit>,
-C<is_utf8_space>, C<is_utf8_xdigit>. C<is_utf8_xidcont>, C<is_utf8_xidfirst>,
-C<to_uni_lower_lc>, C<to_uni_title_lc>, and C<to_uni_upper_lc>.
-
-=head1 Performance Enhancements
-
-=over 4
+Exporter has been upgraded from version 5.67 to 5.68.
=item *
-Perl has a new copy-on-write mechanism that avoids the need to copy the
-internal string buffer when assigning from one scalar to another. This
-makes copying large strings appear much faster. Modifying one of the two
-(or more) strings after an assignment will force a copy internally. This
-makes it unnecessary to pass strings by reference for efficiency.
+ExtUtils::CBuilder has been upgraded from version 0.280209 to 0.280210.
-=back
+=item *
-=head1 Modules and Pragmata
+ExtUtils::MakeMaker has been upgraded from version 6.65_01 to 6.66.
-=head2 Updated Modules and Pragmata
+=item *
-=over 4
+IO has been upgraded from version 1.27 to 1.28.
=item *
-L<File::DosGlob> has been upgraded from version 1.08 to 1.09. The internal
-cache of file names that it keeps for each caller is now freed when that
-caller is freed. This means
-C<< use File::DosGlob 'glob'; eval 'scalar <*>' >> no longer leaks memory.
+overload has been upgraded from version 1.21 to 1.22.
=item *
-L<File::Glob> has been upgraded from version 1.18 to 1.19. File::Glob has
-had exactly the same fix as File::DosGlob. Since it is what Perl's own
-C<glob> operator itself uses (except on VMS), this means
-C<< eval 'scalar <*>' >> no longer leaks.
+Storable has been upgraded from version 2.40 to 2.41.
=item *
-L<GDBM_File> has been upgraded from version 1.14 to 1.15. The undocumented
-optional fifth parameter to C<TIEHASH> has been removed. This was intended
-to provide control of the callback used by C<gdbm*> functions in case of
-fatal errors (such as filesystem problems), but did not work (and could
-never have worked). No code on CPAN even attempted to use it. The callback
-is now always the previous default, C<croak>. Problems on some platforms with
-how the C<C> C<croak> function is called have also been resolved.
+warnings has been upgraded from version 1.17 to 1.18.
=back
-=head1 Documentation
-
=head2 Changes to Existing Documentation
-=head3 L<perlapi/Character classes>
+=head3 Asian-language documentation
-=over 4
-
-=item *
-
-There are quite a few macros callable from XS modules that classify
-characters into things like alphabetic, punctuation, etc. More of these
-are now documented, including ones which work on characters whose code
-points are outside the Latin-1 range.
-
-=back
+The Asian-language documentation, previously stored in a few different
+encodings, have been transcoded to UTF-8.
=head1 Diagnostics
including warnings and fatal error messages. For the complete list of
diagnostic messages, see L<perldiag>.
-=head2 Changes to Existing Diagnostics
+=head3 New Warnings
=over 4
=item *
-L<Constant(%s): Call to &{$^H{%s}} did not return a defined value|perldiag/Constant(%s): Call to &{$^H{%s}} did not return a defined value>
-
-Constant overloading that returns C<undef> results in this error message.
-For numeric constants, it used to say "Constant(undef)". "undef" has been
-replaced with the number itself.
-
-=back
-
-=head1 Internal Changes
-
-=over 4
+L<Smartmatch is experimental|perldiag/"Smartmatch is experimental">
=item *
-SvUPGRADE() is no longer an expression. Originally this macro (and its
-underlying function, sv_upgrade()) were documented as boolean, although
-in reality they always croaked on error and never returned false. In 2005
-the documentation was updated to specify a void return value, but
-SvUPGRADE() was left always returning 1 for backwards compatibility. This
-has now been removed, and SvUPGRADE() is now a statement with no return
-value.
-
-So this is now a syntax error:
-
- if (!SvUPGRADE(sv)) { croak(...); }
-
-If you have code like that, simply replace it with
-
- SvUPGRADE(sv);
-
-or to to avoid compiler warnings with older perls, possibly
-
- (void)SvUPGRADE(sv);
+L<given is experimental|perldiag/"given is experimental">
=item *
-Perl has a new copy-on-write mechanism that allows any SvPOK scalar to be
-upgraded to a copy-on-write scalar. A reference count on the string buffer
-is stored in the string buffer itself.
-
-This breaks a few XS modules by allowing copy-on-write scalars to go
-through code paths that never encountered them before.
-
-This behaviour can still be disabled by running F<Configure> with
-B<-Accflags=-DPERL_NO_COW>. This option will probably be removed in Perl
-5.20.
-
-=item *
+L<when is experimental|perldiag/"when is experimental">
-Copy-on-write no longer uses the SvFAKE and SvREADONLY flags. Hence,
-SvREADONLY indicates a true read-only SV.
+=back
-Use the SvIsCOW macro (as before) to identify a copy-on-write scalar.
+=head1 Platform Support
-=item *
+=head2 Platform-Specific Notes
-C<PL_sawampersand> is now a constant. The switch this variable provided
-(to enable/disable the pre-match copy depending on whether C<$&> had been
-seen) has been removed and replaced with copy-on-write, eliminating a few
-bugs.
+=over 4
-The previous behaviour can still be enabled by running F<Configure> with
-B<-Accflags=-DPERL_SAWAMPERSAND>.
+=item VMS
-=item *
+As of 5.18.0, Perl on VMS can (at last) be built in and installed from a
+directory having dots in the name, so it is no longer necessary to rename the
+top-level source directory before building.
-PL_glob_index is gone.
+The pertinent instructions have been removed from README.vms, so we also no
+longer need to update the version number that was embedded in those
+instructions.
=back
=over 4
-=item *
-
-C<sort {undef} ...> under fatal warnings no longer crashes. It started
-crashing in Perl 5.16.
-
-=item *
-
-Stashes blessed into each other
-(C<bless \%Foo::, 'Bar'; bless \%Bar::, 'Foo'>) no longer result in double
-frees. This bug started happening in Perl 5.16.
-
-=item *
-
-Numerous memory leaks have been fixed, mostly involving fatal warnings and
-syntax errors.
-
-=item *
-
-Lexical constants (C<my sub answer () { 42 }>) no longer cause double
-frees.
+=item Make vms.c's Perl_flex_fstat preserve errno on success
-=item *
-
-Constant subroutine redefinition warns by default, but lexical constants
-were accidentally exempt from default warnings. This has been corrected.
-
-=item *
+=item split's first argument is more consistently interpreted
-Some failed regular expression matches such as C<'f' =~ /../g> were not
-resetting C<pos>. Also, "match-once" patterns (C<m?...?g>) failed to reset
-it, too, when invoked a second time [perl #23180].
+After some changes earlier in 5.17, C<split>'s behavior has been simplified: if
+the PATTERN argument evaluates to a literal string containing one space, it is
+treated the way that a I<literal> string containing one space once was.
-=item *
-
-Accessing C<$&> after a pattern match now works if it had not been seen
-before the match. I.e., this applies to C<${'&'}> (under C<no strict>) and
-C<eval '$&'>. The same applies to C<$'> and C<$`> [perl #4289].
-
-=item *
+=item Handle overloading properly in compile-time regex
-Several bugs involving C<local *ISA> and C<local *Foo::> causing stale
-MRO caches have been fixed.
-
-=item *
-
-Defining a subroutine when its typeglob has been aliased no longer results
-in stale method caches. This bug was introduced in Perl 5.10.
-
-=item *
-
-Localising a typeglob containing a subroutine when the typeglob's package
-has been deleted from its parent stash no longer produces an error. This
-bug was introduced in Perl 5.14.
-
-=item *
-
-Under some circumstances, C<local *method=...> would fail to reset method
-caches upon scope exit.
-
-=item *
-
-C</[.foo.]/> is no longer an error, but produces a warning (as before) and
-is treated as C</[.fo]/> [perl #115818].
-
-=item *
-
-C<goto $tied_var> now calls FETCH before deciding what type of goto
-(subroutine or label) this is.
-
-=item *
-
-Renaming packages through glob assignment
-(C<*Foo:: = *Bar::; *Bar:: = *Baz::>) in combination with C<m?...?> and
-C<reset> no longer makes threaded builds crash.
-
-=item *
-
-An earlier release in the 5.17.x series could crash if user code prevented
-_charnames from loading via C<$INC{'_charnames.pm'}++>.
-
-=item *
-
-A number of bugs related to assigning a list to hash have been fixed. Many of
-these involve lists with repeated keys like C<(1, 1, 1, 1)>.
-
-=over 8
-
-=item -
-
-The expression C<scalar(%h = (1, 1, 1, 1))> now returns C<4>, not C<2>.
-
-=item -
-
-The return value of C<%h = (1, 1, 1)> in list context was wrong. Previously
-this would return C<(1, undef, 1)>, now it returns C<(1, undef)>.
-
-=item -
-
-Perl now issues the same warning on C<($s, %h) = (1, {})> as it does for
-C<(%h) = ({})>, "Reference found where even-sized list expected".
-
-=item -
-
-A number of additional edge cases in list assignment to hashes were
-corrected. For more details see commit 23b7025ebc.
-
-=back
+C<(?{…})> and C<qr> constant overloading did not play nicely together, and when
+C<qr> constant overloading was in effect, C<qr> constructs inside a C<(?{…})>
+construct were incorrectly interpreted. [perl #116823]
=back
=head1 Acknowledgements
-Perl 5.17.7 represents approximately 4 weeks of development since Perl 5.17.6
-and contains approximately 30,000 lines of changes across 490 files from 26
+Perl 5.17.11 represents approximately 4 weeks of development since Perl 5.17.10
+and contains approximately 3,800 lines of changes across 130 files from 17
authors.
Perl continues to flourish into its third decade thanks to a vibrant community
of users and developers. The following people are known to have contributed the
-improvements that became Perl 5.17.7:
-
-Alexandr Ciornii, Bob Ernst, Brian Carlson, Chris 'BinGOs' Williams, Craig A.
-Berry, Daniel Dragan, Dave Rolsky, David Mitchell, Father Chrysostomos, Hugo
-van der Sanden, James E Keenan, Joel Berger, Karl Williamson, Lukas Mai, Martin
-Hasch, Matthew Horsfall, Nicholas Clark, Ricardo Signes, Ruslan Zakirov, Sergey
-Alekseev, Steffen Müller, Sullivan Beck, Sven Strickroth, Sébastien
-Aperghis-Tramoni, Tony Cook, Yves Orton.
+improvements that became Perl 5.17.11:
+
+Aaron Crane, Andy Dougherty, Brian Fraser, Chris 'BinGOs' Williams, Craig A.
+Berry, David Mitchell, François Perrad, James E Keenan, Jan Dubois, Karl
+Williamson, Leon Timmermans, Max Maischein, Moritz Lenz, Nicholas Clark,
+Ricardo Signes, Tony Cook, Yves Orton.
The list above is almost certainly incomplete as it is automatically generated
from version control history. In particular, it does not include the names of
https://perl5.git.perl.org / perl5.git / blobdiff