diff options
Diffstat (limited to 'Master/tlpkg/tlperl.straw/lib/pods/perldelta.pod')
| -rwxr-xr-x | Master/tlpkg/tlperl.straw/lib/pods/perldelta.pod | 1772 |
1 files changed, 1772 insertions, 0 deletions
diff --git a/Master/tlpkg/tlperl.straw/lib/pods/perldelta.pod b/Master/tlpkg/tlperl.straw/lib/pods/perldelta.pod new file mode 100755 index 00000000000..508990c7aac --- /dev/null +++ b/Master/tlpkg/tlperl.straw/lib/pods/perldelta.pod @@ -0,0 +1,1772 @@ +=head1 NAME + +perldelta - what is new for perl v5.10.1 + +=head1 DESCRIPTION + +This document describes differences between the 5.10.0 release and +the 5.10.1 release. + +If you are upgrading from an earlier release such as 5.8.8, first read +the L<perl5100delta>, which describes differences between 5.8.8 and +5.10.0 + +=head1 Incompatible Changes + +=head2 Switch statement changes + +The handling of complex expressions by the C<given>/C<when> switch +statement has been enhanced. There are two new cases where C<when> now +interprets its argument as a boolean, instead of an expression to be used +in a smart match: + +=over 4 + +=item flip-flop operators + +The C<..> and C<...> flip-flop operators are now evaluated in boolean +context, following their usual semantics; see L<perlop/"Range Operators">. + +Note that, as in perl 5.10.0, C<when (1..10)> will not work to test +whether a given value is an integer between 1 and 10; you should use +C<when ([1..10])> instead (note the array reference). + +However, contrary to 5.10.0, evaluating the flip-flop operators in boolean +context ensures it can now be useful in a C<when()>, notably for +implementing bistable conditions, like in: + + when (/^=begin/ .. /^=end/) { + # do something + } + +=item defined-or operator + +A compound expression involving the defined-or operator, as in +C<when (expr1 // expr2)>, will be treated as boolean if the first +expression is boolean. (This just extends the existing rule that applies +to the regular or operator, as in C<when (expr1 || expr2)>.) + +=back + +The next section details more changes brought to the semantics to +the smart match operator, that naturally also modify the behaviour +of the switch statements where smart matching is implicitly used. + +=head2 Smart match changes + +=head3 Changes to type-based dispatch + +The smart match operator C<~~> is no longer commutative. The behaviour of +a smart match now depends primarily on the type of its right hand +argument. Moreover, its semantics have been adjusted for greater +consistency or usefulness in several cases. While the general backwards +compatibility is maintained, several changes must be noted: + +=over 4 + +=item * + +Code references with an empty prototype are no longer treated specially. +They are passed an argument like the other code references (even if they +choose to ignore it). + +=item * + +C<%hash ~~ sub {}> and C<@array ~~ sub {}> now test that the subroutine +returns a true value for each key of the hash (or element of the +array), instead of passing the whole hash or array as a reference to +the subroutine. + +=item * + +Due to the commutativity breakage, code references are no longer +treated specially when appearing on the left of the C<~~> operator, +but like any vulgar scalar. + +=item * + +C<undef ~~ %hash> is always false (since C<undef> can't be a key in a +hash). No implicit conversion to C<""> is done (as was the case in perl +5.10.0). + +=item * + +C<$scalar ~~ @array> now always distributes the smart match across the +elements of the array. It's true if one element in @array verifies +C<$scalar ~~ $element>. This is a generalization of the old behaviour +that tested whether the array contained the scalar. + +=back + +The full dispatch table for the smart match operator is given in +L<perlsyn/"Smart matching in detail">. + +=head3 Smart match and overloading + +According to the rule of dispatch based on the rightmost argument type, +when an object overloading C<~~> appears on the right side of the +operator, the overload routine will always be called (with a 3rd argument +set to a true value, see L<overload>.) However, when the object will +appear on the left, the overload routine will be called only when the +rightmost argument is a simple scalar. This way distributivity of smart match +across arrays is not broken, as well as the other behaviours with complex +types (coderefs, hashes, regexes). Thus, writers of overloading routines +for smart match mostly need to worry only with comparing against a scalar, +and possibly with stringification overloading; the other common cases +will be automatically handled consistently. + +C<~~> will now refuse to work on objects that do not overload it (in order +to avoid relying on the object's underlying structure). (However, if the +object overloads the stringification or the numification operators, and +if overload fallback is active, it will be used instead, as usual.) + +=head2 Other incompatible changes + +=over 4 + +=item * + +The semantics of C<use feature :5.10*> have changed slightly. +See L<"Modules and Pragmata"> for more information. + +=item * + +It is now a run-time error to use the smart match operator C<~~> +with an object that has no overload defined for it. (This way +C<~~> will not break encapsulation by matching against the +object's internal representation as a reference.) + +=item * + +The version control system used for the development of the perl +interpreter has been switched from Perforce to git. This is mainly an +internal issue that only affects people actively working on the perl core; +but it may have minor external visibility, for example in some of details +of the output of C<perl -V>. See L<perlrepository> for more information. + +=item * + +The internal structure of the C<ext/> directory in the perl source has +been reorganised. In general, a module C<Foo::Bar> whose source was +stored under F<ext/Foo/Bar/> is now located under F<ext/Foo-Bar/>. Also, +some modules have been moved from F<lib/> to F<ext/>. This is purely a +source tarball change, and should make no difference to the compilation or +installation of perl, unless you have a very customised build process that +explicitly relies on this structure, or which hard-codes the C<nonxs_ext> +F<Configure> parameter. Specifically, this change does not by default +alter the location of any files in the final installation. + +=item * + +As part of the C<Test::Harness> 2.x to 3.x upgrade, the experimental +C<Test::Harness::Straps> module has been removed. +See L</"Updated Modules"> for more details. + +=item * + +As part of the C<ExtUtils::MakeMaker> upgrade, the +C<ExtUtils::MakeMaker::bytes> and C<ExtUtils::MakeMaker::vmsish> modules +have been removed from this distribution. + +=item * + +C<Module::CoreList> no longer contains the C<%:patchlevel> hash. + +=item * + +This one is actually a change introduced in 5.10.0, but it was missed +from that release's perldelta, so it is mentioned here instead. + +A bugfix related to the handling of the C</m> modifier and C<qr> resulted +in a change of behaviour between 5.8.x and 5.10.0: + + # matches in 5.8.x, doesn't match in 5.10.0 + $re = qr/^bar/; "foo\nbar" =~ /$re/m; + +=back + +=head1 Core Enhancements + +=head2 Unicode Character Database 5.1.0 + +The copy of the Unicode Character Database included in Perl 5.10.1 has +been updated to 5.1.0 from 5.0.0. See +L<http://www.unicode.org/versions/Unicode5.1.0/#NotableChanges> for the +notable changes. + +=head2 A proper interface for pluggable Method Resolution Orders + +As of Perl 5.10.1 there is a new interface for plugging and using method +resolution orders other than the default (linear depth first search). +The C3 method resolution order added in 5.10.0 has been re-implemented as +a plugin, without changing its Perl-space interface. See L<perlmroapi> for +more information. + +=head2 The C<overloading> pragma + +This pragma allows you to lexically disable or enable overloading +for some or all operations. (Yuval Kogman) + +=head2 Parallel tests + +The core distribution can now run its regression tests in parallel on +Unix-like platforms. Instead of running C<make test>, set C<TEST_JOBS> in +your environment to the number of tests to run in parallel, and run +C<make test_harness>. On a Bourne-like shell, this can be done as + + TEST_JOBS=3 make test_harness # Run 3 tests in parallel + +An environment variable is used, rather than parallel make itself, because +L<TAP::Harness> needs to be able to schedule individual non-conflicting test +scripts itself, and there is no standard interface to C<make> utilities to +interact with their job schedulers. + +Note that currently some test scripts may fail when run in parallel (most +notably C<ext/IO/t/io_dir.t>). If necessary run just the failing scripts +again sequentially and see if the failures go away. + +=head2 DTrace support + +Some support for DTrace has been added. See "DTrace support" in F<INSTALL>. + +=head2 Support for C<configure_requires> in CPAN module metadata + +Both C<CPAN> and C<CPANPLUS> now support the C<configure_requires> keyword +in the C<META.yml> metadata file included in most recent CPAN distributions. +This allows distribution authors to specify configuration prerequisites that +must be installed before running F<Makefile.PL> or F<Build.PL>. + +See the documentation for C<ExtUtils::MakeMaker> or C<Module::Build> for more +on how to specify C<configure_requires> when creating a distribution for CPAN. + +=head1 Modules and Pragmata + +=head2 New Modules and Pragmata + +=over 4 + +=item C<autodie> + +This is a new lexically-scoped alternative for the C<Fatal> module. +The bundled version is 2.06_01. Note that in this release, using a string +eval when C<autodie> is in effect can cause the autodie behaviour to leak +into the surrounding scope. See L<autodie/"BUGS"> for more details. + +=item C<Compress::Raw::Bzip2> + +This has been added to the core (version 2.020). + +=item C<parent> + +This pragma establishes an ISA relationship with base classes at compile +time. It provides the key feature of C<base> without the feature creep. + +=item C<Parse::CPAN::Meta> + +This has been added to the core (version 1.39). + +=back + +=head2 Pragmata Changes + +=over 4 + +=item C<attributes> + +Upgraded from version 0.08 to 0.09. + +=item C<attrs> + +Upgraded from version 1.02 to 1.03. + +=item C<base> + +Upgraded from version 2.13 to 2.14. See L<parent> for a replacement. + +=item C<bigint> + +Upgraded from version 0.22 to 0.23. + +=item C<bignum> + +Upgraded from version 0.22 to 0.23. + +=item C<bigrat> + +Upgraded from version 0.22 to 0.23. + +=item C<charnames> + +Upgraded from version 1.06 to 1.07. + +The Unicode F<NameAliases.txt> database file has been added. This has the +effect of adding some extra C<\N> character names that formerly wouldn't +have been recognised; for example, C<"\N{LATIN CAPITAL LETTER GHA}">. + +=item C<constant> + +Upgraded from version 1.13 to 1.17. + +=item C<feature> + +The meaning of the C<:5.10> and C<:5.10.X> feature bundles has +changed slightly. The last component, if any (i.e. C<X>) is simply ignored. +This is predicated on the assumption that new features will not, in +general, be added to maintenance releases. So C<:5.10> and C<:5.10.X> +have identical effect. This is a change to the behaviour documented for +5.10.0. + +=item C<fields> + +Upgraded from version 2.13 to 2.14 (this was just a version bump; there +were no functional changes). + +=item C<lib> + +Upgraded from version 0.5565 to 0.62. + +=item C<open> + +Upgraded from version 1.06 to 1.07. + +=item C<overload> + +Upgraded from version 1.06 to 1.07. + +=item C<overloading> + +See L</"The C<overloading> pragma"> above. + +=item C<version> + +Upgraded from version 0.74 to 0.77. + +=back + +=head2 Updated Modules + +=over 4 + +=item C<Archive::Extract> + +Upgraded from version 0.24 to 0.34. + +=item C<Archive::Tar> + +Upgraded from version 1.38 to 1.52. + +=item C<Attribute::Handlers> + +Upgraded from version 0.79 to 0.85. + +=item C<AutoLoader> + +Upgraded from version 5.63 to 5.68. + +=item C<AutoSplit> + +Upgraded from version 1.05 to 1.06. + +=item C<B> + +Upgraded from version 1.17 to 1.22. + +=item C<B::Debug> + +Upgraded from version 1.05 to 1.11. + +=item C<B::Deparse> + +Upgraded from version 0.83 to 0.89. + +=item C<B::Lint> + +Upgraded from version 1.09 to 1.11. + +=item C<B::Xref> + +Upgraded from version 1.01 to 1.02. + +=item C<Benchmark> + +Upgraded from version 1.10 to 1.11. + +=item C<Carp> + +Upgraded from version 1.08 to 1.11. + +=item C<CGI> + +Upgraded from version 3.29 to 3.43. +(also includes the "default_value for popup_menu()" fix from 3.45). + +=item C<Compress::Zlib> + +Upgraded from version 2.008 to 2.020. + +=item C<CPAN> + +Upgraded from version 1.9205 to 1.9402. C<CPAN::FTP> has a local fix to +stop it being too verbose on download failure. + +=item C<CPANPLUS> + +Upgraded from version 0.84 to 0.88. + +=item C<CPANPLUS::Dist::Build> + +Upgraded from version 0.06_02 to 0.36. + +=item C<Cwd> + +Upgraded from version 3.25_01 to 3.30. + +=item C<Data::Dumper> + +Upgraded from version 2.121_14 to 2.124. + +=item C<DB> + +Upgraded from version 1.01 to 1.02. + +=item C<DB_File> + +Upgraded from version 1.816_1 to 1.820. + +=item C<Devel::PPPort> + +Upgraded from version 3.13 to 3.19. + +=item C<Digest::MD5> + +Upgraded from version 2.36_01 to 2.39. + +=item C<Digest::SHA> + +Upgraded from version 5.45 to 5.47. + +=item C<DirHandle> + +Upgraded from version 1.01 to 1.03. + +=item C<Dumpvalue> + +Upgraded from version 1.12 to 1.13. + +=item C<DynaLoader> + +Upgraded from version 1.08 to 1.10. + +=item C<Encode> + +Upgraded from version 2.23 to 2.35. + +=item C<Errno> + +Upgraded from version 1.10 to 1.11. + +=item C<Exporter> + +Upgraded from version 5.62 to 5.63. + +=item C<ExtUtils::CBuilder> + +Upgraded from version 0.21 to 0.2602. + +=item C<ExtUtils::Command> + +Upgraded from version 1.13 to 1.16. + +=item C<ExtUtils::Constant> + +Upgraded from 0.20 to 0.22. (Note that neither of these versions are +available on CPAN.) + +=item C<ExtUtils::Embed> + +Upgraded from version 1.27 to 1.28. + +=item C<ExtUtils::Install> + +Upgraded from version 1.44 to 1.54. + +=item C<ExtUtils::MakeMaker> + +Upgraded from version 6.42 to 6.55_02. + +Note that C<ExtUtils::MakeMaker::bytes> and C<ExtUtils::MakeMaker::vmsish> +have been removed from this distribution. + +=item C<ExtUtils::Manifest> + +Upgraded from version 1.51_01 to 1.56. + +=item C<ExtUtils::ParseXS> + +Upgraded from version 2.18_02 to 2.2002. + +=item C<Fatal> + +Upgraded from version 1.05 to 2.06_01. See also the new pragma C<autodie>. + +=item C<File::Basename> + +Upgraded from version 2.76 to 2.77. + +=item C<File::Compare> + +Upgraded from version 1.1005 to 1.1006. + +=item C<File::Copy> + +Upgraded from version 2.11 to 2.14. + +=item C<File::Fetch> + +Upgraded from version 0.14 to 0.20. + +=item C<File::Find> + +Upgraded from version 1.12 to 1.14. + +=item C<File::Path> + +Upgraded from version 2.04 to 2.07_03. + +=item C<File::Spec> + +Upgraded from version 3.2501 to 3.30. + +=item C<File::stat> + +Upgraded from version 1.00 to 1.01. + +=item C<File::Temp> + +Upgraded from version 0.18 to 0.22. + +=item C<FileCache> + +Upgraded from version 1.07 to 1.08. + +=item C<FileHandle> + +Upgraded from version 2.01 to 2.02. + +=item C<Filter::Simple> + +Upgraded from version 0.82 to 0.84. + +=item C<Filter::Util::Call> + +Upgraded from version 1.07 to 1.08. + +=item C<FindBin> + +Upgraded from version 1.49 to 1.50. + +=item C<GDBM_File> + +Upgraded from version 1.08 to 1.09. + +=item C<Getopt::Long> + +Upgraded from version 2.37 to 2.38. + +=item C<Hash::Util::FieldHash> + +Upgraded from version 1.03 to 1.04. This fixes a memory leak. + +=item C<I18N::Collate> + +Upgraded from version 1.00 to 1.01. + +=item C<IO> + +Upgraded from version 1.23_01 to 1.25. + +This makes non-blocking mode work on Windows in C<IO::Socket::INET> +[CPAN #43573]. + +=item C<IO::Compress::*> + +Upgraded from version 2.008 to 2.020. + +=item C<IO::Dir> + +Upgraded from version 1.06 to 1.07. + +=item C<IO::Handle> + +Upgraded from version 1.27 to 1.28. + +=item C<IO::Socket> + +Upgraded from version 1.30_01 to 1.31. + +=item C<IO::Zlib> + +Upgraded from version 1.07 to 1.09. + +=item C<IPC::Cmd> + +Upgraded from version 0.40_1 to 0.46. + +=item C<IPC::Open3> + +Upgraded from version 1.02 to 1.04. + +=item C<IPC::SysV> + +Upgraded from version 1.05 to 2.01. + +=item C<lib> + +Upgraded from version 0.5565 to 0.62. + +=item C<List::Util> + +Upgraded from version 1.19 to 1.21. + +=item C<Locale::MakeText> + +Upgraded from version 1.12 to 1.13. + +=item C<Log::Message> + +Upgraded from version 0.01 to 0.02. + +=item C<Math::BigFloat> + +Upgraded from version 1.59 to 1.60. + +=item C<Math::BigInt> + +Upgraded from version 1.88 to 1.89. + +=item C<Math::BigInt::FastCalc> + +Upgraded from version 0.16 to 0.19. + +=item C<Math::BigRat> + +Upgraded from version 0.21 to 0.22. + +=item C<Math::Complex> + +Upgraded from version 1.37 to 1.56. + +=item C<Math::Trig> + +Upgraded from version 1.04 to 1.20. + +=item C<Memoize> + +Upgraded from version 1.01_02 to 1.01_03 (just a minor documentation +change). + +=item C<Module::Build> + +Upgraded from version 0.2808_01 to 0.34_02. + +=item C<Module::CoreList> + +Upgraded from version 2.13 to 2.18. This release no longer contains the +C<%Module::CoreList::patchlevel> hash. + +=item C<Module::Load> + +Upgraded from version 0.12 to 0.16. + +=item C<Module::Load::Conditional> + +Upgraded from version 0.22 to 0.30. + +=item C<Module::Loaded> + +Upgraded from version 0.01 to 0.02. + +=item C<Module::Pluggable> + +Upgraded from version 3.6 to 3.9. + +=item C<NDBM_File> + +Upgraded from version 1.07 to 1.08. + +=item C<Net::Ping> + +Upgraded from version 2.33 to 2.36. + +=item C<NEXT> + +Upgraded from version 0.60_01 to 0.64. + +=item C<Object::Accessor> + +Upgraded from version 0.32 to 0.34. + +=item C<OS2::REXX> + +Upgraded from version 1.03 to 1.04. + +=item C<Package::Constants> + +Upgraded from version 0.01 to 0.02. + +=item C<PerlIO> + +Upgraded from version 1.04 to 1.06. + +=item C<PerlIO::via> + +Upgraded from version 0.04 to 0.07. + +=item C<Pod::Man> + +Upgraded from version 2.16 to 2.22. + +=item C<Pod::Parser> + +Upgraded from version 1.35 to 1.37. + +=item C<Pod::Simple> + +Upgraded from version 3.05 to 3.07. + +=item C<Pod::Text> + +Upgraded from version 3.08 to 3.13. + +=item C<POSIX> + +Upgraded from version 1.13 to 1.17. + +=item C<Safe> + +Upgraded from 2.12 to 2.18. + +=item C<Scalar::Util> + +Upgraded from version 1.19 to 1.21. + +=item C<SelectSaver> + +Upgraded from 1.01 to 1.02. + +=item C<SelfLoader> + +Upgraded from 1.11 to 1.17. + +=item C<Socket> + +Upgraded from 1.80 to 1.82. + +=item C<Storable> + +Upgraded from 2.18 to 2.20. + +=item C<Switch> + +Upgraded from version 2.13 to 2.14. Please see L</Deprecations>. + +=item C<Symbol> + +Upgraded from version 1.06 to 1.07. + +=item C<Sys::Syslog> + +Upgraded from version 0.22 to 0.27. + +=item C<Term::ANSIColor> + +Upgraded from version 1.12 to 2.00. + +=item C<Term::ReadLine> + +Upgraded from version 1.03 to 1.04. + +=item C<Term::UI> + +Upgraded from version 0.18 to 0.20. + +=item C<Test::Harness> + +Upgraded from version 2.64 to 3.17. + +Note that one side-effect of the 2.x to 3.x upgrade is that the +experimental C<Test::Harness::Straps> module (and its supporting +C<Assert>, C<Iterator>, C<Point> and C<Results> modules) have been +removed. If you still need this, then they are available in the +(unmaintained) C<Test-Harness-Straps> distribution on CPAN. + +=item C<Test::Simple> + +Upgraded from version 0.72 to 0.92. + +=item C<Text::ParseWords> + +Upgraded from version 3.26 to 3.27. + +=item C<Text::Tabs> + +Upgraded from version 2007.1117 to 2009.0305. + +=item C<Text::Wrap> + +Upgraded from version 2006.1117 to 2009.0305. + +=item C<Thread::Queue> + +Upgraded from version 2.00 to 2.11. + +=item C<Thread::Semaphore> + +Upgraded from version 2.01 to 2.09. + +=item C<threads> + +Upgraded from version 1.67 to 1.72. + +=item C<threads::shared> + +Upgraded from version 1.14 to 1.29. + +=item C<Tie::RefHash> + +Upgraded from version 1.37 to 1.38. + +=item C<Tie::StdHandle> + +This has documentation changes, and has been assigned a version for the +first time: version 4.2. + +=item C<Time::HiRes> + +Upgraded from version 1.9711 to 1.9719. + +=item C<Time::Local> + +Upgraded from version 1.18 to 1.1901. + +=item C<Time::Piece> + +Upgraded from version 1.12 to 1.15. + +=item C<Unicode::Normalize> + +Upgraded from version 1.02 to 1.03. + +=item C<Unicode::UCD> + +Upgraded from version 0.25 to 0.27. + +C<charinfo()> now works on Unified CJK code points added to later versions +of Unicode. + +C<casefold()> has new fields returned to provide both a simpler interface +and previously missing information. The old fields are retained for +backwards compatibility. Information about Turkic-specific code points is +now returned. + +The documentation has been corrected and expanded. + +=item C<UNIVERSAL> + +Upgraded from version 1.04 to 1.05. + +=item C<Win32> + +Upgraded from version 0.34 to 0.39. + +=item C<Win32API::File> + +Upgraded from version 0.1001_01 to 0.1101. + +=item C<XSLoader> + +Upgraded from version 0.08 to 0.10. + +=back + +=head1 Utility Changes + +=over 4 + +=item F<h2ph> + +Now looks in C<include-fixed> too, which is a recent addition to gcc's +search path. + +=item F<h2xs> + +No longer incorrectly treats enum values like macros (Daniel Burr). + +Now handles C++ style constants (C<//>) properly in enums. (A patch from +Rainer Weikusat was used; Daniel Burr also proposed a similar fix). + +=item F<perl5db.pl> + +C<LVALUE> subroutines now work under the debugger. + +The debugger now correctly handles proxy constant subroutines, and +subroutine stubs. + +=item F<perlthanks> + +Perl 5.10.1 adds a new utility F<perlthanks>, which is a variant of +F<perlbug>, but for sending non-bug-reports to the authors and maintainers +of Perl. Getting nothing but bug reports can become a bit demoralising: +we'll see if this changes things. + +=back + +=head1 New Documentation + +=over 4 + +=item L<perlhaiku> + +This contains instructions on how to build perl for the Haiku platform. + +=item L<perlmroapi> + +This describes the new interface for pluggable Method Resolution Orders. + +=item L<perlperf> + +This document, by Richard Foley, provides an introduction to the use of +performance and optimization techniques which can be used with particular +reference to perl programs. + +=item L<perlrepository> + +This describes how to access the perl source using the I<git> version +control system. + +=item L<perlthanks> + +This describes the new F<perlthanks> utility. + +=back + +=head1 Changes to Existing Documentation + +The various large C<Changes*> files (which listed every change made to perl +over the last 18 years) have been removed, and replaced by a small file, +also called C<Changes>, which just explains how that same information may +be extracted from the git version control system. + +The file F<Porting/patching.pod> has been deleted, as it mainly described +interacting with the old Perforce-based repository, which is now obsolete. +Information still relevant has been moved to L<perlrepository>. + +L<perlapi>, L<perlintern>, L<perlmodlib> and L<perltoc> are now all +generated at build time, rather than being shipped as part of the release. + +=head1 Performance Enhancements + +=over 4 + +=item * + +A new internal cache means that C<isa()> will often be faster. + +=item * + +Under C<use locale>, the locale-relevant information is now cached on +read-only values, such as the list returned by C<keys %hash>. This makes +operations such as C<sort keys %hash> in the scope of C<use locale> much +faster. + +=item * + +Empty C<DESTROY> methods are no longer called. + +=back + +=head1 Installation and Configuration Improvements + +=head2 F<ext/> reorganisation + +The layout of directories in F<ext> has been revised. Specifically, all +extensions are now flat, and at the top level, with C</> in pathnames +replaced by C<->, so that F<ext/Data/Dumper/> is now F<ext/Data-Dumper/>, +etc. The names of the extensions as specified to F<Configure>, and as +reported by C<%Config::Config> under the keys C<dynamic_ext>, +C<known_extensions>, C<nonxs_ext> and C<static_ext> have not changed, and +still use C</>. Hence this change will not have any affect once perl is +installed. However, C<Attribute::Handlers>, C<Safe> and C<mro> have now +become extensions in their own right, so if you run F<Configure> with +options to specify an exact list of extensions to build, you will need to +change it to account for this. + +For 5.10.2, it is planned that many dual-life modules will have been moved +from F<lib> to F<ext>; again this will have no effect on an installed +perl, but will matter if you invoke F<Configure> with a pre-canned list of +extensions to build. + +=head2 Configuration improvements + +If C<vendorlib> and C<vendorarch> are the same, then they are only added to +C<@INC> once. + +C<$Config{usedevel}> and the C-level C<PERL_USE_DEVEL> are now defined if +perl is built with C<-Dusedevel>. + +F<Configure> will enable use of C<-fstack-protector>, to provide protection +against stack-smashing attacks, if the compiler supports it. + +F<Configure> will now determine the correct prototypes for re-entrant +functions, and for C<gconvert>, if you are using a C++ compiler rather +than a C compiler. + +On Unix, if you build from a tree containing a git repository, the +configuration process will note the commit hash you have checked out, for +display in the output of C<perl -v> and C<perl -V>. Unpushed local commits +are automatically added to the list of local patches displayed by +C<perl -V>. + +=head2 Compilation improvements + +As part of the flattening of F<ext>, all extensions on all platforms are +built by F<make_ext.pl>. This replaces the Unix-specific +F<ext/util/make_ext>, VMS-specific F<make_ext.com> and Win32-specific +F<win32/buildext.pl>. + +=head2 Platform Specific Changes + +=over 4 + +=item AIX + +Removed F<libbsd> for AIX 5L and 6.1. Only flock() was used from F<libbsd>. + +Removed F<libgdbm> for AIX 5L and 6.1. The F<libgdbm> is delivered as an +optional package with the AIX Toolbox. Unfortunately the 64 bit version +is broken. + +Hints changes mean that AIX 4.2 should work again. + +=item Cygwin + +On Cygwin we now strip the last number from the DLL. This has been the +behaviour in the cygwin.com build for years. The hints files have been +updated. + +=item FreeBSD + +The hints files now identify the correct threading libraries on FreeBSD 7 +and later. + +=item Irix + +We now work around a bizarre preprocessor bug in the Irix 6.5 compiler: +C<cc -E -> unfortunately goes into K&R mode, but C<cc -E file.c> doesn't. + +=item Haiku + +Patches from the Haiku maintainers have been merged in. Perl should now +build on Haiku. + +=item MirOS BSD + +Perl should now build on MirOS BSD. + +=item NetBSD + +Hints now supports versions 5.*. + +=item Stratus VOS + +Various changes from Stratus have been merged in. + +=item Symbian + +There is now support for Symbian S60 3.2 SDK and S60 5.0 SDK. + +=item Win32 + +Improved message window handling means that C<alarm> and C<kill> messages +will no longer be dropped under race conditions. + +=item VMS + +Reads from the in-memory temporary files of C<PerlIO::scalar> used to fail +if C<$/> was set to a numeric reference (to indicate record-style reads). +This is now fixed. + +VMS now supports C<getgrgid>. + +Many improvements and cleanups have been made to the VMS file name handling +and conversion code. + +Enabling the C<PERL_VMS_POSIX_EXIT> logical name now encodes a POSIX exit +status in a VMS condition value for better interaction with GNV's bash +shell and other utilities that depend on POSIX exit values. See +L<perlvms/"$?"> for details. + +=back + +=head1 Selected Bug Fixes + +=over 4 + +=item * + +5.10.0 inadvertently disabled an optimisation, which caused a measurable +performance drop in list assignment, such as is often used to assign +function parameters from C<@_>. The optimisation has been re-instated, and +the performance regression fixed. + +=item * + +Fixed memory leak on C<while (1) { map 1, 1 }> [RT #53038]. + +=item * + +Some potential coredumps in PerlIO fixed [RT #57322,54828]. + +=item * + +The debugger now works with lvalue subroutines. + +=item * + +The debugger's C<m> command was broken on modules that defined constants +[RT #61222]. + +=item * + +C<crypt()> and string complement could return tainted values for untainted +arguments [RT #59998]. + +=item * + +The C<-i.suffix> command-line switch now recreates the file using +restricted permissions, before changing its mode to match the original +file. This eliminates a potential race condition [RT #60904]. + +=item * + +On some UNIX systems, the value in C<$?> would not have the top bit set +(C<$? & 128>) even if the child core dumped. + +=item * + +Under some circumstances, $^R could incorrectly become undefined +[RT #57042]. + +=item * + +(XS) In various hash functions, passing a pre-computed hash to when the +key is UTF-8 might result in an incorrect lookup. + +=item * + +(XS) Including F<XSUB.h> before F<perl.h> gave a compile-time error +[RT #57176]. + +=item * + +C<< $object->isa('Foo') >> would report false if the package C<Foo> didn't +exist, even if the object's C<@ISA> contained C<Foo>. + +=item * + +Various bugs in the new-to 5.10.0 mro code, triggered by manipulating +C<@ISA>, have been found and fixed. + +=item * + +Bitwise operations on references could crash the interpreter, e.g. +C<$x=\$y; $x |= "foo"> [RT #54956]. + +=item * + +Patterns including alternation might be sensitive to the internal UTF-8 +representation, e.g. + + my $byte = chr(192); + my $utf8 = chr(192); utf8::upgrade($utf8); + $utf8 =~ /$byte|X}/i; # failed in 5.10.0 + +=item * + +Within UTF8-encoded Perl source files (i.e. where C<use utf8> is in +effect), double-quoted literal strings could be corrupted where a C<\xNN>, +C<\0NNN> or C<\N{}> is followed by a literal character with ordinal value +greater than 255 [RT #59908]. + +=item * + +C<B::Deparse> failed to correctly deparse various constructs: +C<readpipe STRING> [RT #62428], C<CORE::require(STRING)> [RT #62488], +C<sub foo(_)> [RT #62484]. + +=item * + +Using C<setpgrp()> with no arguments could corrupt the perl stack. + +=item * + +The block form of C<eval> is now specifically trappable by C<Safe> and +C<ops>. Previously it was erroneously treated like string C<eval>. + +=item * + +In 5.10.0, the two characters C<[~> were sometimes parsed as the smart +match operator (C<~~>) [RT #63854]. + +=item * + +In 5.10.0, the C<*> quantifier in patterns was sometimes treated as +C<{0,32767}> [RT #60034, #60464]. For example, this match would fail: + + ("ab" x 32768) =~ /^(ab)*$/ + +=item * + +C<shmget> was limited to a 32 bit segment size on a 64 bit OS [RT #63924]. + +=item * + +Using C<next> or C<last> to exit a C<given> block no longer produces a +spurious warning like the following: + + Exiting given via last at foo.pl line 123 + +=item * + +On Windows, C<'.\foo'> and C<'..\foo'> were treated differently than +C<'./foo'> and C<'../foo'> by C<do> and C<require> [RT #63492]. + +=item * + +Assigning a format to a glob could corrupt the format; e.g.: + + *bar=*foo{FORMAT}; # foo format now bad + +=item * + +Attempting to coerce a typeglob to a string or number could cause an +assertion failure. The correct error message is now generated, +C<Can't coerce GLOB to I<$type>>. + +=item * + +Under C<use filetest 'access'>, C<-x> was using the wrong access mode. This +has been fixed [RT #49003]. + +=item * + +C<length> on a tied scalar that returned a Unicode value would not be +correct the first time. This has been fixed. + +=item * + +Using an array C<tie> inside in array C<tie> could SEGV. This has been +fixed. [RT #51636] + +=item * + +A race condition inside C<PerlIOStdio_close()> has been identified and +fixed. This used to cause various threading issues, including SEGVs. + +=item * + +In C<unpack>, the use of C<()> groups in scalar context was internally +placing a list on the interpreter's stack, which manifested in various +ways, including SEGVs. This is now fixed [RT #50256]. + +=item * + +Magic was called twice in C<substr>, C<\&$x>, C<tie $x, $m> and C<chop>. +These have all been fixed. + +=item * + +A 5.10.0 optimisation to clear the temporary stack within the implicit +loop of C<s///ge> has been reverted, as it turned out to be the cause of +obscure bugs in seemingly unrelated parts of the interpreter [commit +ef0d4e17921ee3de]. + +=item * + +The line numbers for warnings inside C<elsif> are now correct. + +=item * + +The C<..> operator now works correctly with ranges whose ends are at or +close to the values of the smallest and largest integers. + +=item * + +C<binmode STDIN, ':raw'> could lead to segmentation faults on some platforms. +This has been fixed [RT #54828]. + +=item * + +An off-by-one error meant that C<index $str, ...> was effectively being +executed as C<index "$str\0", ...>. This has been fixed [RT #53746]. + +=item * + +Various leaks associated with named captures in regexes have been fixed +[RT #57024]. + +=item * + +A weak reference to a hash would leak. This was affecting C<DBI> +[RT #56908]. + +=item * + +Using (?|) in a regex could cause a segfault [RT #59734]. + +=item * + +Use of a UTF-8 C<tr//> within a closure could cause a segfault [RT #61520]. + +=item * + +Calling C<sv_chop()> or otherwise upgrading an SV could result in an +unaligned 64-bit access on the SPARC architecture [RT #60574]. + +=item * + +In the 5.10.0 release, C<inc_version_list> would incorrectly list +C<5.10.*> after C<5.8.*>; this affected the C<@INC> search order +[RT #67628]. + +=item * + +In 5.10.0, C<pack "a*", $tainted_value> returned a non-tainted value +[RT #52552]. + +=item * + +In 5.10.0, C<printf> and C<sprintf> could produce the fatal error +C<panic: utf8_mg_pos_cache_update> when printing UTF-8 strings +[RT #62666]. + +=item * + +In the 5.10.0 release, a dynamically created C<AUTOLOAD> method might be +missed (method cache issue) [RT #60220,60232]. + +=item * + +In the 5.10.0 release, a combination of C<use feature> and C<//ee> could +cause a memory leak [RT #63110]. + +=item * + +C<-C> on the shebang (C<#!>) line is once more permitted if it is also +specified on the command line. C<-C> on the shebang line used to be a +silent no-op I<if> it was not also on the command line, so perl 5.10.0 +disallowed it, which broke some scripts. Now perl checks whether it is +also on the command line and only dies if it is not [RT #67880]. + +=item * + +In 5.10.0, certain types of re-entrant regular expression could crash, +or cause the following assertion failure [RT #60508]: + + Assertion rx->sublen >= (s - rx->subbeg) + i failed + + +=back + +=head1 New or Changed Diagnostics + +=over 4 + +=item C<panic: sv_chop %s> + +This new fatal error occurs when the C routine C<Perl_sv_chop()> was +passed a position that is not within the scalar's string buffer. This +could be caused by buggy XS code, and at this point recovery is not +possible. + +=item C<Can't locate package %s for the parents of %s> + +This warning has been removed. In general, it only got produced in +conjunction with other warnings, and removing it allowed an ISA lookup +optimisation to be added. + +=item C<v-string in use/require is non-portable> + +This warning has been removed. + +=item C<Deep recursion on subroutine "%s"> + +It is now possible to change the depth threshold for this warning from the +default of 100, by recompiling the F<perl> binary, setting the C +pre-processor macro C<PERL_SUB_DEPTH_WARN> to the desired value. + +=back + +=head1 Changed Internals + +=over 4 + +=item * + +The J.R.R. Tolkien quotes at the head of C source file have been checked and +proper citations added, thanks to a patch from Tom Christiansen. + +=item * + +C<vcroak()> now accepts a null first argument. In addition, a full audit +was made of the "not NULL" compiler annotations, and those for several +other internal functions were corrected. + +=item * + +New macros C<dSAVEDERRNO>, C<dSAVE_ERRNO>, C<SAVE_ERRNO>, C<RESTORE_ERRNO> +have been added to formalise the temporary saving of the C<errno> +variable. + +=item * + +The function C<Perl_sv_insert_flags> has been added to augment +C<Perl_sv_insert>. + +=item * + +The function C<Perl_newSV_type(type)> has been added, equivalent to +C<Perl_newSV()> followed by C<Perl_sv_upgrade(type)>. + +=item * + +The function C<Perl_newSVpvn_flags()> has been added, equivalent to +C<Perl_newSVpvn()> and then performing the action relevant to the flag. + +Two flag bits are currently supported. + +=over 4 + +=item C<SVf_UTF8> + +This will call C<SvUTF8_on()> for you. (Note that this does not convert an +sequence of ISO 8859-1 characters to UTF-8). A wrapper, C<newSVpvn_utf8()> +is available for this. + +=item C<SVs_TEMP> + +Call C<sv_2mortal()> on the new SV. + +=back + +There is also a wrapper that takes constant strings, C<newSVpvs_flags()>. + +=item * + +The function C<Perl_croak_xs_usage> has been added as a wrapper to +C<Perl_croak>. + +=item * + +The functions C<PerlIO_find_layer> and C<PerlIO_list_alloc> are now +exported. + +=item * + +C<PL_na> has been exterminated from the core code, replaced by local STRLEN +temporaries, or C<*_nolen()> calls. Either approach is faster than C<PL_na>, +which is a pointer deference into the interpreter structure under ithreads, +and a global variable otherwise. + +=item * + +C<Perl_mg_free()> used to leave freed memory accessible via SvMAGIC() on +the scalar. It now updates the linked list to remove each piece of magic +as it is freed. + +=item * + +Under ithreads, the regex in C<PL_reg_curpm> is now reference counted. This +eliminates a lot of hackish workarounds to cope with it not being reference +counted. + +=item * + +C<Perl_mg_magical()> would sometimes incorrectly turn on C<SvRMAGICAL()>. +This has been fixed. + +=item * + +The I<public> IV and NV flags are now not set if the string value has +trailing "garbage". This behaviour is consistent with not setting the +public IV or NV flags if the value is out of range for the type. + +=item * + +SV allocation tracing has been added to the diagnostics enabled by C<-Dm>. +The tracing can alternatively output via the C<PERL_MEM_LOG> mechanism, if +that was enabled when the F<perl> binary was compiled. + +=item * + +Uses of C<Nullav>, C<Nullcv>, C<Nullhv>, C<Nullop>, C<Nullsv> etc have been +replaced by C<NULL> in the core code, and non-dual-life modules, as C<NULL> +is clearer to those unfamiliar with the core code. + +=item * + +A macro C<MUTABLE_PTR(p)> has been added, which on (non-pedantic) gcc will +not cast away C<const>, returning a C<void *>. Macros C<MUTABLE_SV(av)>, +C<MUTABLE_SV(cv)> etc build on this, casting to C<AV *> etc without +casting away C<const>. This allows proper compile-time auditing of +C<const> correctness in the core, and helped picked up some errors (now +fixed). + +=item * + +Macros C<mPUSHs()> and C<mXPUSHs()> have been added, for pushing SVs on the +stack and mortalizing them. + +=item * + +Use of the private structure C<mro_meta> has changed slightly. Nothing +outside the core should be accessing this directly anyway. + +=item * + +A new tool, C<Porting/expand-macro.pl> has been added, that allows you +to view how a C preprocessor macro would be expanded when compiled. +This is handy when trying to decode the macro hell that is the perl +guts. + +=back + +=head1 New Tests + +Many modules updated from CPAN incorporate new tests. + +Several tests that have the potential to hang forever if they fail now +incorporate a "watchdog" functionality that will kill them after a timeout, +which helps ensure that C<make test> and C<make test_harness> run to +completion automatically. (Jerry Hedden). + +Some core-specific tests have been added: + +=over 4 + +=item t/comp/retainedlines.t + +Check that the debugger can retain source lines from C<eval>. + +=item t/io/perlio_fail.t + +Check that bad layers fail. + +=item t/io/perlio_leaks.t + +Check that PerlIO layers are not leaking. + +=item t/io/perlio_open.t + +Check that certain special forms of open work. + +=item t/io/perlio.t + +General PerlIO tests. + +=item t/io/pvbm.t + +Check that there is no unexpected interaction between the internal types +C<PVBM> and C<PVGV>. + +=item t/mro/package_aliases.t + +Check that mro works properly in the presence of aliased packages. + +=item t/op/dbm.t + +Tests for C<dbmopen> and C<dbmclose>. + +=item t/op/index_thr.t + +Tests for the interaction of C<index> and threads. + +=item t/op/pat_thr.t + +Tests for the interaction of esoteric patterns and threads. + +=item t/op/qr_gc.t + +Test that C<qr> doesn't leak. + +=item t/op/reg_email_thr.t + +Tests for the interaction of regex recursion and threads. + +=item t/op/regexp_qr_embed_thr.t + +Tests for the interaction of patterns with embedded C<qr//> and threads. + +=item t/op/regexp_unicode_prop.t + +Tests for Unicode properties in regular expressions. + +=item t/op/regexp_unicode_prop_thr.t + +Tests for the interaction of Unicode properties and threads. + +=item t/op/reg_nc_tie.t + +Test the tied methods of C<Tie::Hash::NamedCapture>. + +=item t/op/reg_posixcc.t + +Check that POSIX character classes behave consistently. + +=item t/op/re.t + +Check that exportable C<re> functions in F<universal.c> work. + +=item t/op/setpgrpstack.t + +Check that C<setpgrp> works. + +=item t/op/substr_thr.t + +Tests for the interaction of C<substr> and threads. + +=item t/op/upgrade.t + +Check that upgrading and assigning scalars works. + +=item t/uni/lex_utf8.t + +Check that Unicode in the lexer works. + +=item t/uni/tie.t + +Check that Unicode and C<tie> work. + +=back + +=head1 Known Problems + +This is a list of some significant unfixed bugs, which are regressions +from either 5.10.0 or 5.8.x. + +=over 4 + +=item * + +C<List::Util::first> misbehaves in the presence of a lexical C<$_> +(typically introduced by C<my $_> or implicitly by C<given>). The variable +which gets set for each iteration is the package variable C<$_>, not the +lexical C<$_> [RT #67694]. + +A similar issue may occur in other modules that provide functions which +take a block as their first argument, like + + foo { ... $_ ...} list + +=item * + +The C<charnames> pragma may generate a run-time error when a regex is +interpolated [RT #56444]: + + use charnames ':full'; + my $r1 = qr/\N{THAI CHARACTER SARA I}/; + "foo" =~ $r1; # okay + "foo" =~ /$r1+/; # runtime error + +A workaround is to generate the character outside of the regex: + + my $a = "\N{THAI CHARACTER SARA I}"; + my $r1 = qr/$a/; + +=item * + +Some regexes may run much more slowly when run in a child thread compared +with the thread the pattern was compiled into [RT #55600]. + + +=back + +=head1 Deprecations + +The following items are now deprecated. + +=over 4 + +=item * + +C<Switch> is buggy and should be avoided. From perl 5.11.0 onwards, it is +intended that any use of the core version of this module will emit a +warning, and that the module will eventually be removed from the core +(probably in perl 5.14.0). See L<perlsyn/"Switch statements"> for its +replacement. + +=item * + +C<suidperl> will be removed in 5.12.0. This provides a mechanism to +emulate setuid permission bits on systems that don't support it properly. + +=back + +=head1 Acknowledgements + +Some of the work in this release was funded by a TPF grant. + +Nicholas Clark officially retired from maintenance pumpking duty at the +end of 2008; however in reality he has put much effort in since then to +help get 5.10.1 into a fit state to be released, including writing a +considerable chunk of this perldelta. + +Steffen Mueller and David Golden in particular helped getting CPAN modules +polished and synchronised with their in-core equivalents. + +Craig Berry was tireless in getting maint to run under VMS, no matter how +many times we broke it for him. + +The other core committers contributed most of the changes, and applied most +of the patches sent in by the hundreds of contributors listed in F<AUTHORS>. + +(Sorry to all the people I haven't mentioned by name). + +Finally, thanks to Larry Wall, without whom none of this would be +necessary. + +=head1 Reporting Bugs + +If you find what you think is a bug, you might check the articles +recently posted to the comp.lang.perl.misc newsgroup and the perl +bug database at http://rt.perl.org/perlbug/ . There may also be +information at http://www.perl.org/ , the Perl Home Page. + +If you believe you have an unreported bug, please run the B<perlbug> +program included with your release. Be sure to trim your bug down +to a tiny but sufficient test case. Your bug report, along with the +output of C<perl -V>, will be sent off to perlbug@perl.org to be +analysed by the Perl porting team. + +If the bug you are reporting has security implications, which make it +inappropriate to send to a publicly archived mailing list, then please send +it to perl5-security-report@perl.org. This points to a closed subscription +unarchived mailing list, which includes all the core committers, who be able +to help assess the impact of issues, figure out a resolution, and help +co-ordinate the release of patches to mitigate or fix the problem across all +platforms on which Perl is supported. Please only use this address for +security issues in the Perl core, not for modules independently +distributed on CPAN. + +=head1 SEE ALSO + +The F<Changes> file for an explanation of how to view exhaustive details +on what changed. + +The F<INSTALL> file for how to build Perl. + +The F<README> file for general stuff. + +The F<Artistic> and F<Copying> files for copyright information. + +=cut |