=head1 NAME
-perldelta - what is new for perl v5.17.6
+[ this is a template for a new perldelta file. Any text flagged as XXX needs
+to be processed before release. ]
+
+perldelta - what is new for perl v5.17.7
=head1 DESCRIPTION
-This document describes differences between the 5.17.5 release and the 5.17.6
+This document describes differences between the 5.17.6 release and the 5.17.7
release.
-If you are upgrading from an earlier release such as 5.17.4, first read
-L<perl5175delta>, which describes differences between 5.17.4 and 5.17.5.
+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 Notice
+
+XXX Any important notices here
=head1 Core Enhancements
-=head2 Character name aliases may now include non-Latin1-range characters
+XXX New core language features go here. Summarize user-visible core language
+enhancements. Particularly prominent performance optimisations could go
+here, but most should go in the L</Performance Enhancements> section.
-It is possible to define your own names for characters for use in
-C<\N{...}>, C<charnames::vianame()>, etc. These names can now be
-comprised of characters from the whole Unicode range. This allows for
-names to be in your native language, and not just English. Certain
-restrictions apply to the characters that may be used (you can't define
-a name that has punctuation in it, for example). See L<charnames/CUSTOM
-ALIASES>.
+[ List each enhancement as a =head2 entry ]
-=head2 New hash function Murmurhash-32 (v3)
+=head1 Security
-We have switched Perl's hash function to use Murmurhash-32, and added build
-support for several other hash functions. This new function is expected to
-perform equivalently to the old one for shorter strings and is faster,
-potentially twice as fast, for hashing longer strings.
+XXX Any security-related notices go here. In particular, any security
+vulnerabilities closed should be noted here rather than in the
+L</Selected Bug Fixes> section.
-=head1 Incompatible Changes
+[ List each security issue as a =head2 entry ]
-=head2 An unknown character name in C<\N{...}> is now a syntax error
+=head1 Incompatible Changes
-Previously, it warned, and the Unicode REPLACEMENT CHARACTER was
-substituted. Unicode now recommends that this situation be a syntax
-error. Also, the previous behavior led to some confusing warnings and
-behaviors, and since the REPLACEMENT CHARACTER has no use other than as
-a stand-in for some unknown character, any code that has this problem is
-buggy.
+=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
+
+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.
+
+=head1 Deprecations
+
+XXX Any deprecated features, syntax, modules etc. should be listed here. In
+particular, deprecated modules should be listed here even if they are listed as
+an updated module in the L</Modules and Pragmata> section.
+
+[ List each deprecation as a =head2 entry ]
+
+=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>.
-=head2 Formerly deprecated characters in C<\N{}> character name aliases are now errors.
+=head1 Performance Enhancements
-Since v5.12.0, it has been deprecated to use certain characters in
-user-defined C<\N{...}> character names. These now cause a syntax
-error. For example, it is now an error to begin a name with a digit,
-such as in
+XXX Changes which enhance performance without changing behaviour go here.
+There may well be none in a stable release.
- my $undraftable = "\N{4F}"; # Syntax error!
+[ List each enhancement as a =item entry ]
-or to have commas anywhere in the name. See L<charnames/CUSTOM ALIASES>
+=over 4
-=head2 Per process hash randomization
+=item *
-The seed used by Perl's hash function is now random. This means that the
-order which keys/values will be returned from functions like C<keys()>,
-C<values()>, and C<each()> will differ from run to run.
+XXX
-This change was introduced to make Perl's hashes more robust to algorithmic
-complexity attacks, and also because we discovered that it exposes hash
-ordering dependency bugs and makes them easier to track down.
+=back
-Toolchain maintainers might want to invest in additional infrastructure to
-test for things like this. Running tests several times in a row and then
-comparing results will make it easier to spot hash order dependencies in
-code. Authors are strongly encouraged not to expose the key order of
-Perl's hashes to insecure audiences.
+=head1 Modules and Pragmata
-=head2 PERL_HASH_SEED enviornment variable now takes a hex value
+XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
+go here. If Module::CoreList is updated, generate an initial draft of the
+following sections using F<Porting/corelist-perldelta.pl>, which prints stub
+entries to STDOUT. Results can be pasted in place of the '=head2' entries
+below. A paragraph summary for important changes should then be added by hand.
+In an ideal world, dual-life modules would have a F<Changes> file that could be
+cribbed.
-PERL_HASH_SEED no longer accepts an integer as a parameter, instead the
-value is expected to be a binary string encoded in hex. This is to make
-the infrastructure support hash seeds of arbitrary lengths which might
-exceed that of an integer. (SipHash uses a 16 byte seed).
+[ Within each section, list entries as a =item entry ]
-=head2 Hash::Util::hash_seed() now returns a string
+=head2 New Modules and Pragmata
-Hash::Util::hash_seed() now returns a string instead of an integer. This
-is to make the infrastructure support hash seeds of arbitrary lengths
-which might exceed that of an integer. (SipHash uses a 16 byte seed).
+=over 4
-=head2 Output of PERL_HASH_SEED_DEBUG has been changed
+=item *
-The environment variable PERL_HASH_SEED_DEBUG now shows both the hash
-function perl was built with AND the seed, in hex in use for that process.
-Code parsing this output, should it exist, must change to accomodate the
-new format. Example of the new format:
+XXX
- $ PERL_HASH_SEED_DEBUG=1 ./perl -e1
- HASH_FUNCTION = MURMUR3 HASH_SEED = 0x1476bb9f
+=back
-=head1 Performance Enhancements
+=head2 Updated Modules and Pragmata
=over 4
=item *
-Lists of lexical variable declarations (C<my($x, $y)>) are now optimised
-down to a single op, and are hence faster than before.
+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.
-=item *
+=back
+
+=head2 Removed Modules and Pragmata
+
+=over 4
-A new C preprocessor define NO_TAINT_SUPPORT was added that, if set, disables
-Perl's taint support altogether. Using the -T or -t command line flags will
-cause a fatal error. Beware that both core tests as well as many a CPAN
-distribution's tests will fail with this change. On the upside, it provides
-a small performance benefit due to reduced branching.
+=item *
-B<Do not enable this unless you know exactly what you are getting yourself
-into.>
+XXX
=back
-=head1 Modules and Pragmata
+=head1 Documentation
-=head2 Updated Modules and Pragmata
+XXX Changes to files in F<pod/> go here. Consider grouping entries by
+file and be sure to link to the appropriate page, e.g. L<perlfunc>.
+
+=head2 New Documentation
+
+XXX Changes which create B<new> files in F<pod/> go here.
+
+=head3 L<XXX>
+
+XXX Description of the purpose of the new file here
+
+=head2 Changes to Existing Documentation
+
+XXX Changes which significantly change existing files in F<pod/> go here.
+However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
+section.
+
+=head3 L<perlapi/Character classes>
=over 4
=item *
-L<Carp> has been upgraded from version 1.27 to 1.28.
+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.
-Carp is no longer confused when C<caller> returns undef for a package that
-has been deleted.
+=back
-=item *
+=head1 Diagnostics
-L<CPAN> has been upgraded from version 1.98 to 1.99_51.
+The following additions or changes have been made to diagnostic output,
+including warnings and fatal error messages. For the complete list of
+diagnostic messages, see L<perldiag>.
-=item *
+XXX New or changed warnings emitted by the core's C<C> code go here. Also
+include any changes in L<perldiag> that reconcile it to the C<C> code.
+
+=head2 New Diagnostics
-L<DynaLoader> has been upgraded from version 1.16 to 1.17.
+XXX Newly added diagnostic messages go under here, separated into New Errors
+and New Warnings
+
+=head3 New Errors
+
+=over 4
=item *
-L<Env> has been upgraded from version 1.03 to 1.04.
+XXX L<message|perldiag/"message">
-Its SPLICE implementation no longer misbehaves in list context.
+=back
+
+=head3 New Warnings
+
+=over 4
=item *
-L<Tie::Hash::NamedCapture> has been upgraded from version 0.08 to 0.09.
+XXX L<message|perldiag/"message">
=back
-=head2 Changes to Existing Documentation
+=head2 Changes to Existing Diagnostics
-=head3 L<perlref>
+XXX Changes (i.e. rewording) of diagnostic messages go here
=over 4
=item *
-C<*foo{NAME}> and C<*foo{PACKAGE}>, which have existed since perl 5.005,
-are now documented.
+XXX Describe change here
=back
-=head1 Platform Support
+=head1 Utility Changes
-=head2 Discontinued Platforms
+XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go here.
+Most of these are built within the directories F<utils> and F<x2p>.
+
+[ List utility changes as a =head3 entry for each utility and =item
+entries for each change
+Use L<XXX> with program names to get proper documentation linking. ]
+
+=head3 L<XXX>
=over 4
-=item EPOC
+=item *
-Support code relating to EPOC has been removed. EPOC was a family of
-operating systems developed by Psion for mobile devices. It was the
-predecessor of Symbian. The port was last updated in April 2002.
+XXX
=back
-=head2 Platform-Specific Notes
+=head1 Configuration and Compilation
-=over 4
+XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
+go here. Any other changes to the Perl build process should be listed here.
+However, any platform-specific changes should be listed in the
+L</Platform Support> section, instead.
-=item VMS
+[ List changes as a =item entry ].
-Where possible, the case of filenames and command-line arguments is now
-preserved by enabling the CRTL features C<DECC$EFS_CASE_PRESERVE> and
-C<DECC$ARGV_PARSE_STYLE> at start-up time. The latter only takes effect
-when extended parse is enabled in the process from which Perl is run.
+=over 4
-=item WinCE
+=item *
-Building on WinCE is now possible once again, although more work is required
-to fully restore a clean build.
+XXX
=back
-=head1 Internal Changes
+=head1 Testing
+
+XXX Any significant changes to the testing of a freshly built perl should be
+listed here. Changes which create B<new> files in F<t/> go here as do any
+large changes to the testing harness (e.g. when parallel testing was added).
+Changes to existing files in F<t/> aren't worth summarizing, although the bugs
+that they represent may be covered elsewhere.
+
+[ List each test improvement as a =item entry ]
=over 4
=item *
-The private Perl_croak_no_modify has had its context parameter removed. It is
-now has a void prototype. Users of the public API croak_no_modify remain
-unaffected.
+XXX
-=item *
+=back
-Copy-on-write (shared hash key) scalars are no longer marked read-only.
-C<SvREADONLY> returns false on such an SV, but C<SvIsCOW> still returns
-true.
+=head1 Platform Support
-=item *
+XXX Any changes to platform support should be listed in the sections below.
+
+[ Within the sections, list each platform as a =item entry with specific
+changes as paragraphs below it. ]
-A new op type, C<OP_PADRANGE> has been introduced. The perl peephole
-optimiser will, where possible, substitute a single padrange op for a
-pushmark followed by one or more pad ops, and possibly also skipping list
-and nextstate ops. In addition, the op can carry out the tasks associated
-with the RHS of a my(...) = @_ assignment, so those ops may be optimised
-away too.
+=head2 New Platforms
+
+XXX List any platforms that this version of perl compiles on, that previous
+versions did not. These will either be enabled by new files in the F<hints/>
+directories, or new subdirectories and F<README> files at the top level of the
+source tree.
+
+=over 4
+
+=item XXX-some-platform
+
+XXX
=back
-=head1 Selected Bug Fixes
+=head2 Discontinued Platforms
=over 4
-=item *
+=item BeOS
-Uninitialized warnings mentioning hash elements would only mention the
-element name if it was not in the first bucket of the hash, due to an
-off-by-one error.
+Support for BeOS has been removed.
-=item *
+=back
-A regular expression optimizer bug could cause multiline "^" to behave
-incorrectly in the presence of line breaks, such that
-C<"/\n\n" =~ m#\A(?:^/$)#im> would not match [perl #115242].
+=head2 Platform-Specific Notes
-=item *
+XXX List any changes for specific platforms. This could include configuration
+and compilation changes or changes in portability/compatibility. However,
+changes within modules for platforms should generally be listed in the
+L</Modules and Pragmata> section.
-Failed C<fork> in list context no longer currupts the stack.
-C<@a = (1, 2, fork, 3)> used to gobble up the 2 and assign C<(1, undef, 3)>
-if the C<fork> call failed.
+=over 4
-=item *
+=item XXX-some-platform
-Numerous memory leaks have been fixed, mostly involving tied variables that
-die, regular expression character classes and code blocks, and syntax
-errors.
+XXX
-=item *
+=back
-Assigning a regular expression (C<${qr//}>) to a variable that happens to
-hold a floating point number no longer causes assertion failures on
-debugging builds.
+=head1 Internal Changes
-=item *
+XXX Changes which affect the interface available to C<XS> code go here. Other
+significant internal changes for future core maintainers should be noted as
+well.
-Assigning a regular expression to a scalar containing a number no longer
-causes subsequent nummification to produce random numbers.
+[ List each change as a =item entry ]
+
+=over 4
=item *
-Assigning a regular expression to a magic variable no longer wipes away the
-magic. This is a regression from 5.10.
+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.
-=item *
+So this is now a syntax error:
-Assigning a regular expression to a blessed scalar no longer results in
-crashes. This is also a regression from 5.10.
+ if (!SvUPGRADE(sv)) { croak(...); }
-=item *
+If you have code like that, simply replace it with
-Regular expression can now be assigned to tied hash and array elements with
-flattening into strings.
+ SvUPGRADE(sv);
-=item *
+or to to avoid compiler warnings with older perls, possibly
-Nummifying a regular expression no longer results in an uninitialized
-warning.
+ (void)SvUPGRADE(sv);
-=item *
+=back
-Negative array indices no longer cause EXISTS methods of tied variables to
-be ignored. This is a regression from 5.12.
+=head1 Selected Bug Fixes
-=item *
+XXX Important bug fixes in the core language are summarized here. Bug fixes in
+files in F<ext/> and F<lib/> are best summarized in L</Modules and Pragmata>.
-Negative array indices no longer result in crashes on arrays tied to
-non-objects.
+[ List each fix as a =item entry ]
+
+=over 4
=item *
-C<$x = "(?{})"; /a++(?{})+$x/x> no longer erroneous produces an error (just
-a warning, as expected). This was broken in 5.17.1.
+C<sort {undef} ...> under fatal warnings no longer crashes. It started
+crashing in Perl 5.16.
=item *
-C<$byte_overload .= $utf8> no longer results in doubly-encoded UTF8 if the
-left-hand scalar happened to have produced a UTF8 string the last time
-overloading was invoked.
+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 *
-C<goto &sub> now uses the current value of @_, instead of using the array
-the subroutine was originally called with. This means
-C<local @_ = (...); goto &sub> now works [perl #43077].
+Numerous memory leaks have been fixed, mostly involving fatal warnings and
+syntax errors.
=item *
-If a debugger is invoked recursively, it no longer stomps on its own
-lexical variables. Formerly under recursion all calls would share the same
-set of lexical variables [perl #115742].
+Lexical constants (C<my sub answer () { 42 }>) no longer cause double
+frees.
+
+=back
+
+=head1 Known Problems
+
+XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
+tests that had to be C<TODO>ed for the release would be noted here. Unfixed
+platform specific bugs also go here.
+
+[ List each fix as a =item entry ]
+
+=over 4
=item *
-C<*_{ARRAY}> returned from a subroutine no longer spontaneously
-becomes empty.
+XXX
=back
+=head1 Obituary
+
+XXX If any significant core contributor has died, we've added a short obituary
+here.
+
=head1 Acknowledgements
-Perl 5.17.6 represents approximately 5 weeks of development since Perl 5.17.5
-and contains approximately 79,000 lines of changes across 460 files from 30
-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 5.17.6:
-
-Alexandr Ciornii, Brian Fraser, Chris 'BinGOs' Williams, Craig A. Berry,
-Dagfinn Ilmari Mannsåker, Daniel Dragan, David Golden, David Mitchell, Dominic
-Hargreaves, Eric Brine, Father Chrysostomos, Florian Ragwitz, Hugo van der
-Sanden, James E Keenan, Jerry D. Hedden, Jesse Luehrs, Karl Williamson, Lukas
-Mai, Nicholas Clark, Paul Johnson, Reini Urban, Ricardo Signes, Ruslan Zakirov,
-Shlomi Fish, Steffen Müller, Steve Hay, Tom Wyant, Tony Cook, Vadim Konovalov,
-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
-the (very much appreciated) contributors who reported issues to the Perl bug
-tracker.
-
-Many of the changes included in this version originated in the CPAN modules
-included in Perl's core. We're grateful to the entire CPAN community for
-helping Perl to flourish.
-
-For a more complete list of all of Perl's historical contributors, please see
-the F<AUTHORS> file in the Perl source distribution.
+XXX Generate this with:
+
+ perl Porting/acknowledgements.pl v5.17.6..HEAD
=head1 Reporting Bugs
https://perl5.git.perl.org / perl5.git / blobdiff