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Most of the REGEXP-massaging modules have now been updated.
[perl5.git] / pod / perl5120delta.pod
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1=encoding utf8
2
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3=head1 NAME
4
5perl5120delta - what is new for perl v5.12.0
6
7=head1 DESCRIPTION
8
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9This document describes differences between the 5.10.0 release and the
105.12.0 release.
01358b4a 11
72d4e865 12Many of the bug fixes in 5.12.0 are already included in the 5.10.1
702b4ef6 13maintenance release.
72d4e865 14
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15You can see the list of those changes in the 5.10.1 release notes
16(L<perl5101delta>).
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17
18
b6381718 19=head1 Core Enhancements
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20
21=head2 New C<package NAME VERSION> syntax
22
23This new syntax allows a module author to set the $VERSION of a namespace
24when the namespace is declared with 'package'. It eliminates the need
25for C<our $VERSION = ...> and similar constructs. E.g.
26
27 package Foo::Bar 1.23;
28 # $Foo::Bar::VERSION == 1.23
29
30There are several advantages to this:
31
208f012a 32=over
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33
34=item *
35
36C<$VERSION> is parsed in exactly the same way as C<use NAME VERSION>
37
38=item *
39
40C<$VERSION> is set at compile time
41
42=item *
43
44C<$VERSION> is a version object that provides proper overloading of
4655b0a1 45comparison operators so comparing C<$VERSION> to decimal (1.23) or
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46dotted-decimal (v1.2.3) version numbers works correctly.
47
48=item *
49
50Eliminates C<$VERSION = ...> and C<eval $VERSION> clutter
51
52=item *
53
54As it requires VERSION to be a numeric literal or v-string
55literal, it can be statically parsed by toolchain modules
56without C<eval> the way MM-E<gt>parse_version does for C<$VERSION = ...>
57
e014eb68 58=back
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59
60It does not break old code with only C<package NAME>, but code that uses
61C<package NAME VERSION> will need to be restricted to perl 5.12.0 or newer
62This is analogous to the change to C<open> from two-args to three-args.
63Users requiring the latest Perl will benefit, and perhaps after several
64years, it will become a standard practice.
65
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66
67However, C<package NAME VERSION> requires a new, 'strict' version
68number format. See L<"Version number formats"> for details.
69
70
71=head2 The C<...> operator
72
73A new operator, C<...>, nicknamed the Yada Yada operator, has been added.
74It is intended to mark placeholder code that is not yet implemented.
79849ba8 75See L<perlop/"Yada Yada Operator">.
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76
77=head2 Implicit strictures
78
79Using the C<use VERSION> syntax with a version number greater or equal
80to 5.11.0 will lexically enable strictures just like C<use strict>
81would do (in addition to enabling features.) The following:
82
83 use 5.12.0;
84
85means:
86
87 use strict;
88 use feature ':5.12';
01358b4a 89
b6381718 90=head2 Unicode improvements
01358b4a 91
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92Perl 5.12 comes with Unicode 5.2, the latest version available to
93us at the time of release. This version of Unicode was released in
94October 2009. See L<http://www.unicode.org/versions/Unicode5.2.0> for
95further details about what's changed in this version of the standard.
96See L<perlunicode> for instructions on installing and using other versions
97of Unicode.
98
99Additionally, Perl's developers have significantly improved Perl's Unicode
100implementation. For full details, see L</Unicode overhaul> below.
101
102=head2 Y2038 compliance
103
104Perl's core time-related functions are now Y2038 compliant. (It may not mean much to you, but your kids will love it!)
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105
106=head2 qr overloading
107
108It is now possible to overload the C<qr//> operator, that is,
109conversion to regexp, like it was already possible to overload
110conversion to boolean, string or number of objects. It is invoked when
c66407fa 111an object appears on the right hand side of the C<=~> operator or when
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112it is interpolated into a regexp. See L<overload>.
113
114=head2 Pluggable keywords
115
116Extension modules can now cleanly hook into the Perl parser to define
117new kinds of keyword-headed expression and compound statement. The
118syntax following the keyword is defined entirely by the extension. This
119allow a completely non-Perl sublanguage to be parsed inline, with the
208f012a 120correct ops cleanly generated.
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121
122See L<perlapi/PL_keyword_plugin> for the mechanism. The Perl core
123source distribution also includes a new module
124L<XS::APItest::KeywordRPN>, which implements reverse Polish notation
125arithmetic via pluggable keywords. This module is mainly used for test
126purposes, and is not normally installed, but also serves as an example
127of how to use the new mechanism.
128
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129Perl's developers consider this feature to be experimental. We may remove
130it or change it in a backwards-incompatible way in Perl 5.14.
131
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132=head2 APIs for more internals
133
134The lowest layers of the lexer and parts of the pad system now have C
135APIs available to XS extensions. These are necessary to support proper
136use of pluggable keywords, but have other uses too. The new APIs are
137experimental, and only cover a small proportion of what would be
138necessary to take full advantage of the core's facilities in these
139areas. It is intended that the Perl 5.13 development cycle will see the
140addition of a full range of clean, supported interfaces.
141
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142Perl's developers consider this feature to be experimental. We may remove
143it or change it in a backwards-incompatible way in Perl 5.14.
144
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145=head2 Overridable function lookup
146
147Where an extension module hooks the creation of rv2cv ops to modify the
148subroutine lookup process, this now works correctly for bareword
149subroutine calls. This means that prototypes on subroutines referenced
150this way will be processed correctly. (Previously bareword subroutine
151names were initially looked up, for parsing purposes, by an unhookable
152mechanism, so extensions could only properly influence subroutine names
153that appeared with an C<&> sigil.)
154
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155=head2 A proper interface for pluggable Method Resolution Orders
156
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157As of Perl 5.12.0 there is a new interface for plugging and using method
158resolution orders other than the default linear depth first search.
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159The C3 method resolution order added in 5.10.0 has been re-implemented as
160a plugin, without changing its Perl-space interface. See L<perlmroapi> for
161more information.
162
b3b85878 163
5e75e599 164
72d4e865 165=head2 C<\N> experimental regex escape
3ab3a109 166
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167Perl now supports C<\N>, a new regex escape which you can think of as
168the inverse of C<\n>. It will match any character that is not a newline,
169independently from the presence or absence of the single line match
170modifier C</s>. It is not usable within a character class. C<\N{3}>
171means to match 3 non-newlines; C<\N{5,}> means to match at least 5.
172C<\N{NAME}> still means the character or sequence named C<NAME>, but
173C<NAME> no longer can be things like C<3>, or C<5,>.
174
175This will break a L<custom charnames translator|charnames/CUSTOM
176TRANSLATORS> which allows numbers for character names, as C<\N{3}> will
177now mean to match 3 non-newline characters, and not the character whose
178name is C<3>. (No name defined by the Unicode standard is a number,
179so only custom translators might be affected.)
180
181Perl's developers are somewhat concerned about possible user confusion
182with the existing C<\N{...}> construct which matches characters by their
183Unicode name. Consequently, this feature is experimental. We may remove
184it or change it in a backwards-incompatible way in Perl 5.14.
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185
186=head2 DTrace support
187
72d4e865 188Perl now has some support for DTrace. See "DTrace support" in F<INSTALL>.
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189
190=head2 Support for C<configure_requires> in CPAN module metadata
191
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192Both C<CPAN> and C<CPANPLUS> now support the C<configure_requires>
193keyword in the F<META.yml> metadata file included in most recent CPAN
194distributions. This allows distribution authors to specify configuration
195prerequisites that must be installed before running F<Makefile.PL>
196or F<Build.PL>.
3ab3a109 197
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198See the documentation for C<ExtUtils::MakeMaker> or C<Module::Build> for
199more on how to specify C<configure_requires> when creating a distribution
200for CPAN.
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201
202=head2 C<each> is now more flexible
203
204The C<each> function can now operate on arrays.
205
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206=head2 C<when> as a statement modifier
207
208C<when> is now allowed to be used as a statement modifier.
209
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210=head2 C<$,> flexibility
211
212The variable C<$,> may now be tied.
213
61f382b0 214=head2 // in when clauses
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215
216// now behaves like || in when clauses
217
218=head2 Enabling warnings from your shell environment
219
220You can now set C<-W> from the C<PERL5OPT> environment variable
221
222=head2 C<delete local>
223
224C<delete local> now allows you to locally delete a hash entry.
225
226=head2 New support for Abstract namespace sockets
227
228Abstract namespace sockets are Linux-specific socket type that live in
229AF_UNIX family, slightly abusing it to be able to use arbitrary
230character arrays as addresses: They start with nul byte and are not
231terminated by nul byte, but with the length passed to the socket()
232system call.
233
72d4e865 234=head2 32-bit limit on substr arguments removed
3ab3a109 235
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236The 32-bit limit on C<substr> arguments has now been removed. The full
237range of the system's signed and unsigned integers is now available for
238the C<pos> and C<len> arguments.
3ab3a109 239
b6381718 240=head1 Potentially Incompatible Changes
3ab3a109 241
72d4e865 242=head2 Deprecations warn by default
3ab3a109 243
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244Over the years, Perl's developers have deprecated a number of language
245features for a variety of reasons. Perl now defaults to issuing a
246warning if a deprecated language feature is used. Many of the deprecations
247Perl now warns you about have been deprecated for many years. You can
248find a list of what was deprecated in a given release of Perl in the
249C<perl5xxdelta.pod> file for that release.
252eec4f 250
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251To disable this feature in a given lexical scope, you should use C<no
252warnings 'deprecated';> For information about which language features
253are deprecated and explanations of various deprecation warnings, please
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254see L<perldiag.pod>. See L</Deprecations> below for the list of features
255and modules Perl's developers have deprecated as part of this release.
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256
257=head2 Version number formats
258
259Acceptable version number formats have been formalized into "strict" and
72d4e865 260"lax" rules. C<package NAME VERSION> takes a strict version number.
fab55263 261C<UNIVERSAL::VERSION> and the L<version> object constructors take lax
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262version numbers. Providing an invalid version will result in a fatal
263error. The version argument in C<use NAME VERSION> is first parsed as a
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264numeric literal or v-string and then passed to C<UNIVERSAL::VERSION>
265(and must then pass the "lax" format test).
266
72d4e865 267These formats are documented fully in the L<version> module. To a first
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268approximation, a "strict" version number is a positive decimal number
269(integer or decimal-fraction) without exponentiation or else a
270dotted-decimal v-string with a leading 'v' character and at least three
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271components. A "lax" version number allows v-strings with fewer than
272three components or without a leading 'v'. Under "lax" rules, both
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273decimal and dotted-decimal versions may have a trailing "alpha"
274component separated by an underscore character after a fractional or
275dotted-decimal component.
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276
277The L<version> module adds C<version::is_strict> and C<version::is_lax>
278functions to check a scalar against these rules.
279
c66407fa 280=head2 @INC reorganization
3ab3a109 281
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282In C<@INC>, C<ARCHLIB> and C<PRIVLIB> now occur after after the current
283version's C<site_perl> and C<vendor_perl>. Modules installed into
284C<site_perl> and C<vendor_perl> will now be loaded in preference to
285those installed in C<ARCHLIB> and C<PRIVLIB>.
3ab3a109 286
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287
288=head2 REGEXPs are now first class
289
290Internally, Perl now treates compiled regular expressions (such as
291those created with C<qr//>) as first class entities. Perl modules which
292serialize, deserialize or otherwise have deep interaction with Perl's
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293internal data structures need to be updated for this change. Most
294affected CPAN modules have already been updated as of this writing.
055e9e16 295
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296=head2 Switch statement changes
297
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298The C<given>/C<when> switch statement handles complex statements better
299than Perl 5.10.0 did (These enhancements are also available in
3005.10.1 and subsequent 5.10 releases.) There are two new cases where
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301C<when> now interprets its argument as a boolean, instead of an
302expression to be used in a smart match:
3ab3a109 303
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304=over
305
306=item flip-flop operators
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307
308The C<..> and C<...> flip-flop operators are now evaluated in boolean
309context, following their usual semantics; see L<perlop/"Range Operators">.
310
311Note that, as in perl 5.10.0, C<when (1..10)> will not work to test
312whether a given value is an integer between 1 and 10; you should use
313C<when ([1..10])> instead (note the array reference).
314
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315However, contrary to 5.10.0, evaluating the flip-flop operators in
316boolean context ensures it can now be useful in a C<when()>, notably
317for implementing bistable conditions, like in:
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318
319 when (/^=begin/ .. /^=end/) {
320 # do something
321 }
322
b6381718 323=item defined-or operator
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324
325A compound expression involving the defined-or operator, as in
326C<when (expr1 // expr2)>, will be treated as boolean if the first
327expression is boolean. (This just extends the existing rule that applies
328to the regular or operator, as in C<when (expr1 || expr2)>.)
329
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330=back
331
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332=head2 Smart match changes
333
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334Since Perl 5.10.0, Perl's developers have made a number of changes to
335the smart match operator. These, of course, also alter the behaviour
3ab3a109 336of the switch statements where smart matching is implicitly used.
c66407fa 337These changes were also made for the 5.10.1 release, and will remain in
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338subsequent 5.10 releases.
339
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340=head3 Changes to type-based dispatch
341
342The smart match operator C<~~> is no longer commutative. The behaviour of
343a smart match now depends primarily on the type of its right hand
344argument. Moreover, its semantics have been adjusted for greater
345consistency or usefulness in several cases. While the general backwards
346compatibility is maintained, several changes must be noted:
347
348=over 4
349
350=item *
351
352Code references with an empty prototype are no longer treated specially.
353They are passed an argument like the other code references (even if they
354choose to ignore it).
355
356=item *
357
358C<%hash ~~ sub {}> and C<@array ~~ sub {}> now test that the subroutine
359returns a true value for each key of the hash (or element of the
360array), instead of passing the whole hash or array as a reference to
361the subroutine.
362
363=item *
364
365Due to the commutativity breakage, code references are no longer
366treated specially when appearing on the left of the C<~~> operator,
367but like any vulgar scalar.
368
369=item *
370
371C<undef ~~ %hash> is always false (since C<undef> can't be a key in a
372hash). No implicit conversion to C<""> is done (as was the case in perl
3735.10.0).
374
375=item *
376
377C<$scalar ~~ @array> now always distributes the smart match across the
378elements of the array. It's true if one element in @array verifies
379C<$scalar ~~ $element>. This is a generalization of the old behaviour
380that tested whether the array contained the scalar.
381
382=back
383
384The full dispatch table for the smart match operator is given in
385L<perlsyn/"Smart matching in detail">.
386
387=head3 Smart match and overloading
388
389According to the rule of dispatch based on the rightmost argument type,
390when an object overloading C<~~> appears on the right side of the
391operator, the overload routine will always be called (with a 3rd argument
392set to a true value, see L<overload>.) However, when the object will
393appear on the left, the overload routine will be called only when the
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394rightmost argument is a simple scalar. This way, distributivity of smart
395match across arrays is not broken, as well as the other behaviours with
396complex types (coderefs, hashes, regexes). Thus, writers of overloading
397routines for smart match mostly need to worry only with comparing
398against a scalar, and possibly with stringification overloading; the
399other common cases will be automatically handled consistently.
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400
401C<~~> will now refuse to work on objects that do not overload it (in order
402to avoid relying on the object's underlying structure). (However, if the
403object overloads the stringification or the numification operators, and
404if overload fallback is active, it will be used instead, as usual.)
405
b6381718 406=head2 Other potentially incompatible changes
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407
408=over 4
409
410=item *
411
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412The definitions of a number of Unicode properties have changed to match
413those of the current Unicode standard. These are listed above under
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414L</Unicode overhaul>. This change may break code that expects the old
415definitions.
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416
417=item *
418
b6381718 419The boolkeys op has moved to the group of hash ops. This breaks binary
b21d8e53 420compatibility.
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421
422=item *
423
72d4e865 424Filehandles are now always blessed into C<IO::File>.
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425
426The previous behaviour was to bless Filehandles into L<FileHandle>
427(an empty proxy class) if it was loaded into memory and otherwise
428to bless them into C<IO::Handle>.
429
430=item *
431
432The semantics of C<use feature :5.10*> have changed slightly.
433See L<"Modules and Pragmata"> for more information.
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434
435=item *
436
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437Perl's developers now use git, rather than Perforce. This should be
438a purely internal change only relevant to people actively working on
439the core. However, you may see minor difference in perl as a consequence
440of the change. For example in some of details of the output of C<perl
441-V>. See L<perlrepository> for more information.
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442
443=item *
444
445As part of the C<Test::Harness> 2.x to 3.x upgrade, the experimental
446C<Test::Harness::Straps> module has been removed.
b6381718 447See L</"Modules and Pragmata"> for more details.
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448
449=item *
450
451As part of the C<ExtUtils::MakeMaker> upgrade, the
452C<ExtUtils::MakeMaker::bytes> and C<ExtUtils::MakeMaker::vmsish> modules
453have been removed from this distribution.
454
455=item *
456
457C<Module::CoreList> no longer contains the C<%:patchlevel> hash.
458
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459
460=item *
461
462C<length undef> now returns undef.
463
464=item *
465
466Unsupported private C API functions are now declared "static" to prevent
467leakage to Perl's public API.
468
469=item *
470
471To support the bootstrapping process, F<miniperl> no longer builds with
472UTF-8 support in the regexp engine.
473
474This allows a build to complete with PERL_UNICODE set and a UTF-8 locale.
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475Without this there's a bootstrapping problem, as miniperl can't load
476the UTF-8 components of the regexp engine, because they're not yet built.
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477
478=item *
479
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480F<miniperl>'s @INC is now restricted to just C<-I...>, the split of
481C<$ENV{PERL5LIB}>, and "C<.>"
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482
483=item *
484
485A space or a newline is now required after a C<"#line XXX"> directive.
486
487=item *
488
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489Tied filehandles now have an additional method EOF which provides the
490EOF type.
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491
492=item *
493
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494To better match all other flow control statements, C<foreach> may no
495longer be used as an attribute.
3ab3a109 496
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497=item *
498
499Perl's command-line switch "-P", which was deprecated in version 5.10.0, has
500now been removed.
501
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502=back
503
b6381718 504
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505=head1 Deprecations
506
507From time to time, Perl's developers find it necessary to deprecate
508features or modules we've previously shipped as part of the core
509distribution. We are well aware of the pain and frustration that a
510backwards-incompatible change to Perl can cause for developers building
511or maintaining software in Perl. You can be sure that when we deprecate
512a functionality or syntax, it isn't a choice we make lightly. Sometimes,
513we choose to deprecate functionality or syntax because it was found to
514be poorly designed or implemented. Sometimes, this is because they're
515holding back other features or causing performance problems. Sometimes,
516the reasons are more complex. Wherever possible, we try to keep deprecated
517functionality available to developers in its previous form for at least
72d4e865 518one major release. So long as a deprecated feature isn't actively
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519disrupting our ability to maintain and extend Perl, we'll try to leave
520it in place as long as possible.
521
b6381718 522The following items are now deprecated:
3ab3a109 523
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524=over
525
526=item suidperl
527
528C<suidperl> is no longer part of Perl. It used to provide a mechanism to
529emulate setuid permission bits on systems that don't support it properly.
3ab3a109 530
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531
532=item Use of C<:=> to mean an empty attribute list
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533
534An accident of Perl's parser meant that these constructions were all
535equivalent:
536
537 my $pi := 4;
538 my $pi : = 4;
539 my $pi : = 4;
540
541with the C<:> being treated as the start of an attribute list, which
542ends before the C<=>. As whitespace is not significant here, all are
543parsed as an empty attribute list, hence all the above are equivalent
544to, and better written as
545
546 my $pi = 4;
547
548because no attribute processing is done for an empty list.
549
550As is, this meant that C<:=> cannot be used as a new token, without
551silently changing the meaning of existing code. Hence that particular
552form is now deprecated, and will become a syntax error. If it is
553absolutely necessary to have empty attribute lists (for example,
554because of a code generator) then avoid the warning by adding a space
555before the C<=>.
556
c66407fa 557=item C<< UNIVERSAL->import() >>
3ab3a109 558
72d4e865 559The method C<< UNIVERSAL->import() >> is now deprecated. Attempting to
3ab3a109 560pass import arguments to a C<use UNIVERSAL> statement will result in a
c66407fa 561deprecation warning.
3ab3a109 562
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563
564=item Use of "goto" to jump into a construct
3ab3a109 565
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566Using C<goto> to jump from an outer scope into an inner scope is now
567deprecated. This rare use case was causing problems in the
568implementation of scopes.
3ab3a109 569
b6381718 570=item Custom character names in \N{name} that don't look like names
8c66a230 571
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572In C<\N{I<name>}>, I<name> can be just about anything. The standard
573Unicode names have a very limited domain, but a custom name translator
574could create names that are, for example, made up entirely of punctuation
575symbols. It is now deprecated to make names that don't begin with an
576alphabetic character, and aren't alphanumeric or contain other than
577a very few other characters, namely spaces, dashes, parentheses
578and colons. Because of the added meaning of C<\N> (See L</C<\N>
579experimental regex escape>), names that look like curly brace -enclosed
580quantifiers won't work. For example, C<\N{3,4}> now means to match 3 to
5814 non-newlines; before a custom name C<3,4> could have been created.
8c66a230 582
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583=item Deprecated Modules
584
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585The following modules will be removed from the core distribution in a
586future release, and should be installed from CPAN instead. Distributions
587on CPAN which require these should add them to their prerequisites. The
588core versions of these modules warnings will issue a deprecation warning.
3ab3a109 589
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590If you ship a packaged version of Perl, either alone or as part of a
591larger system, then you should carefully consider the reprecussions of
592core module deprecations. You may want to consider shipping your default
593build of Perl with packages for some or all deprecated modules which
594install into C<vendor> or C<site> perl library directories. This will
595inhibit the deprecation warnings.
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596
597Alternatively, you may want to consider patching F<lib/deprecate.pm>
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598to provide deprecation warnings specific to your packaging system
599or distribution of Perl, consistent with how your packaging system
600or distribution manages a staged transition from a release where the
601installation of a single package provides the given functionality, to
602a later release where the system administrator needs to know to install
603multiple packages to get that same functionality.
8df7d2a3 604
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605You can silence these deprecation warnings by installing the modules
606in question from CPAN. To install the latest version of all of them,
e4717ba1 607just install C<Task::Deprecations::5_12>.
34153154 608
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609=over
610
c66407fa
RS
611=item L<Class::ISA>
612
613=item L<Pod::Plainer>
614
615=item L<Shell>
3ab3a109 616
c66407fa 617=item L<Switch>
3ab3a109 618
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619Switch is buggy and should be avoided. You may find Perl's new
620C<given>/C<when> feature a suitable replacement. See L<perlsyn/"Switch
621statements"> for more information.
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622
623=back
624
3ab3a109
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625=item Assignment to $[
626
b6381718 627=item Use of the attribute :locked on subroutines
3ab3a109 628
b6381718 629=item Use of "locked" with the attributes pragma
3ab3a109 630
b6381718 631=item Use of "unique" with the attributes pragma
3ab3a109 632
b6381718 633=item Perl_pmflag
3ab3a109 634
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635C<Perl_pmflag> is no longer part of Perl's public API. Calling it now
636generates a deprecation warning, and it will be removed in a future
637release. Although listed as part of the API, it was never documented,
638and only ever used in F<toke.c>, and prior to 5.10, F<regcomp.c>. In
639core, it has been replaced by a static function.
3ab3a109 640
b6381718 641=item Numerous Perl 4-era libraries
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642
643F<termcap.pl>, F<tainted.pl>, F<stat.pl>, F<shellwords.pl>, F<pwd.pl>,
644F<open3.pl>, F<open2.pl>, F<newgetopt.pl>, F<look.pl>, F<find.pl>,
645F<finddepth.pl>, F<importenv.pl>, F<hostname.pl>, F<getopts.pl>,
646F<getopt.pl>, F<getcwd.pl>, F<flush.pl>, F<fastcwd.pl>, F<exceptions.pl>,
647F<ctime.pl>, F<complete.pl>, F<cacheout.pl>, F<bigrat.pl>, F<bigint.pl>,
648F<bigfloat.pl>, F<assert.pl>, F<abbrev.pl>, F<dotsh.pl>, and
649F<timelocal.pl> are all now deprecated. Using them will incur a warning.
650
b6381718 651
3ab3a109
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652=back
653
b6381718 654=head1 Unicode overhaul
3ab3a109 655
b6381718
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656Perl's developers have made a concerted effort to update Perl to be in
657sync with the latest Unicode standard. Changes for this include:
3ab3a109 658
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659Perl can now handle every Unicode character property. New documentation,
660L<perluniprops>, lists all available non-Unihan character properties. By
661default, perl does not expose Unihan, deprecated or Unicode-internal
662properties. See below for more details on these; there is also a section
663in the pod listing them, and explaining why they are not exposed.
3ab3a109 664
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665Perl now fully supports the Unicode compound-style of using C<=>
666and C<:> in writing regular expressions: C<\p{property=value}> and
b6381718 667C<\p{property:value}> (both of which mean the same thing).
3ab3a109 668
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669Perl now fully supports the Unicode loose matching rules for text between
670the braces in C<\p{...}> constructs. In addition, Perl allows underscores
671between digits of numbers.
3ab3a109 672
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673Perl now accepts all the Unicode-defined synonyms for properties and
674property values.
3ab3a109 675
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676C<qr/\X/>, which matches a Unicode logical character, has
677been expanded to work better with various Asian languages. It
678now is defined as an I<extended grapheme cluster>. (See
679L<http://www.unicode.org/reports/tr29/>). Anything matched previously
680and that made sense will continue to be accepted. Additionally:
3ab3a109 681
b6381718 682=over
3ab3a109 683
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684=item *
685
686C<\X> will not break apart a C<S<CR LF>> sequence.
3ab3a109
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687
688=item *
689
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690C<\X> will now match a sequence which includes the C<ZWJ> and C<ZWNJ>
691characters.
b6381718
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692
693=item *
3ab3a109 694
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695C<\X> will now always match at least one character, including an initial
696mark. Marks generally come after a base character, but it is possible in
697Unicode to have them in isolation, and C<\X> will now handle that case,
698for example at the beginning of a line, or after a C<ZWSP>. And this is
699the part where C<\X> doesn't match the things that it used to that don't
700make sense. Formerly, for example, you could have the nonsensical case
701of an accented LF.
3ab3a109
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702
703=item *
704
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705C<\X> will now match a (Korean) Hangul syllable sequence, and the Thai
706and Lao exception cases.
3ab3a109 707
b6381718 708=back
3ab3a109 709
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710Otherwise, this change should be transparent for the non-affected
711languages.
3ab3a109 712
b6381718 713C<\p{...}> matches using the Canonical_Combining_Class property were
a56dbb5e
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714completely broken in previous releases of Perl. They should now work
715correctly.
716
717Before Perl 5.12, the Unicode C<Decomposition_Type=Compat> property
718and a Perl extension had the same name, which led to neither matching
719all the correct values (with more than 100 mistakes in one, and several
720thousand in the other). The Perl extension has now been renamed to be
721C<Decomposition_Type=Noncanonical> (short: C<dt=noncanon>). It has the
722same meaning as was previously intended, namely the union of all the
723non-canonical Decomposition types, with Unicode C<Compat> being just
724one of those.
3ab3a109 725
b6381718 726C<\p{Decomposition_Type=Canonical}> now includes the Hangul syllables.
3ab3a109 727
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728C<\p{Uppercase}> and C<\p{Lowercase}> now work as the Unicode standard
729says they should. This means they each match a few more characters than
730they used to.
3ab3a109 731
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732C<\p{Cntrl}> now matches the same characters as C<\p{Control}>. This
733means it no longer will match Private Use (gc=co), Surrogates (gc=cs),
734nor Format (gc=cf) code points. The Format code points represent the
735biggest possible problem. All but 36 of them are either officially
736deprecated or strongly discouraged from being used. Of those 36, likely
737the most widely used are the soft hyphen (U+00AD), and BOM, ZWSP, ZWNJ,
738WJ, and similar characters, plus bidirectional controls.
3ab3a109 739
a56dbb5e
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740C<\p{Alpha}> now matches the same characters as C<\p{Alphabetic}>. Before
7415.12, Perl's definition definition included a number of things that aren't
742really alpha (all marks) while omitting many that were. The definitions
743of C<\p{Alnum}> and C<\p{Word}> depend on Alpha's definition and have
744changed accordingly.
3ab3a109 745
a56dbb5e
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746C<\p{Word}> no longer incorrectly matches non-word characters such
747as fractions.
3ab3a109 748
a56dbb5e
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749C<\p{Print}> no longer matches the line control characters: Tab, LF,
750CR, FF, VT, and NEL. This brings it in line with standards and the
751documentation.
3ab3a109 752
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753C<\p{XDigit}> now matches the same characters as C<\p{Hex_Digit}>. This
754means that in addition to the characters it currently matches,
755C<[A-Fa-f0-9]>, it will also match the 22 fullwidth equivalents, for
756example U+FF10: FULLWIDTH DIGIT ZERO.
3ab3a109 757
b6381718
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758The Numeric type property has been extended to include the Unihan
759characters.
3ab3a109 760
b6381718
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761There is a new Perl extension, the 'Present_In', or simply 'In',
762property. This is an extension of the Unicode Age property, but
763C<\p{In=5.0}> matches any code point whose usage has been determined
764I<as of> Unicode version 5.0. The C<\p{Age=5.0}> only matches code points
765added in I<precisely> version 5.0.
3ab3a109 766
b6381718 767A number of properties now have the correct values for unassigned
a56dbb5e
JV
768code points. The affected properties are Bidi_Class, East_Asian_Width,
769Joining_Type, Decomposition_Type, Hangul_Syllable_Type, Numeric_Type,
770and Line_Break.
3ab3a109 771
b6381718
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772The Default_Ignorable_Code_Point, ID_Continue, and ID_Start properties
773are now up to date with current Unicode definitions.
3ab3a109 774
a56dbb5e
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775Earlier versions of Perl erroneously exposed certain properties that
776are supposed to be Unicode internal-only. Use of these in regular
777expressions will now generate, if enabled, a deprecation warning message.
b6381718
JV
778The properties are: Other_Alphabetic, Other_Default_Ignorable_Code_Point,
779Other_Grapheme_Extend, Other_ID_Continue, Other_ID_Start, Other_Lowercase,
780Other_Math, and Other_Uppercase.
3ab3a109 781
b6381718
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782It is now possible to change which Unicode properties Perl understands
783on a per-installation basis. As mentioned above, certain properties
784are turned off by default. These include all the Unihan properties
785(which should be accessible via the CPAN module Unicode::Unihan) and any
786deprecated or Unicode internal-only property that Perl has never exposed.
3ab3a109 787
b6381718 788The generated files in the C<lib/unicore/To> directory are now more
a56dbb5e
JV
789clearly marked as being stable, directly usable by applications. New hash
790entries in them give the format of the normal entries, which allows for
791easier machine parsing. Perl can generate files in this directory for
792any property, though most are suppressed. You can find instructions
793for changing which are written in L<perluniprops>.
3ab3a109 794
b6381718 795=head1 Modules and Pragmata
3ab3a109 796
a56dbb5e 797=head2 New Modules and Pragmata
3ab3a109 798
b6381718 799=over 4
3ab3a109 800
a56dbb5e 801=item C<autodie>
3ab3a109 802
b6381718
JV
803C<autodie> is a new lexically-scoped alternative for the C<Fatal> module.
804The bundled version is 2.06_01. Note that in this release, using a string
805eval when C<autodie> is in effect can cause the autodie behaviour to leak
806into the surrounding scope. See L<autodie/"BUGS"> for more details.
807
a56dbb5e 808Version 2.06_01 has been added to the Perl core.
3ab3a109 809
a56dbb5e 810=item C<Compress::Raw::Bzip2>
3ab3a109 811
a56dbb5e
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812Version 2.024 has been added to the Perl core.
813
814=item C<overloading>
3ab3a109 815
b6381718 816C<overloading> allows you to lexically disable or enable overloading
79849ba8 817for some or all operations.
3ab3a109 818
a56dbb5e
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819Version 0.001 has been added to the Perl core.
820
821=item C<parent>
b6381718
JV
822
823C<parent> establishes an ISA relationship with base classes at compile
824time. It provides the key feature of C<base> without further unwanted
825behaviors.
3ab3a109 826
a56dbb5e
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827Version 0.223 has been added to the Perl core.
828
829=item C<Parse::CPAN::Meta>
3ab3a109 830
a56dbb5e
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831Version 1.40 has been added to the Perl core.
832
833=item C<VMS::DCLsym>
834
835Version 1.03 has been added to the Perl core.
836
837=item C<VMS::Stdio>
838
839Version 2.4 has been added to the Perl core.
840
841=item C<XS::APItest::KeywordRPN>
842
843Version 0.003 has been added to the Perl core.
3ab3a109 844
b6381718 845=back
3ab3a109 846
a56dbb5e 847=head2 Updated Pragmata
3ab3a109 848
b6381718 849=over 4
3ab3a109 850
a56dbb5e
JV
851=item C<base>
852
853Upgraded from version 2.13 to 2.15.
854
855=item C<bignum>
856
857Upgraded from version 0.22 to 0.23.
858
859=item C<charnames>
b6381718
JV
860
861C<charnames> now contains the Unicode F<NameAliases.txt> database file.
862This has the effect of adding some extra C<\N> character names that
863formerly wouldn't have been recognised; for example, C<"\N{LATIN CAPITAL
864LETTER GHA}">.
3ab3a109 865
a56dbb5e
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866Upgraded from version 1.06 to 1.07.
867
868=item C<constant>
869
870Upgraded from version 1.13 to 1.20.
871
872=item C<diagnostics>
873
874C<diagnostics> now supports %.0f formatting internally.
875
876C<diagnostics> no longer suppresses C<Use of uninitialized value in range
877(or flip)> warnings. [perl #71204]
878
879Upgraded from version 1.17 to 1.19.
880
881=item C<feature>
3ab3a109 882
702b4ef6
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883In C<feature>, the meaning of the C<:5.10> and C<:5.10.X> feature
884bundles has changed slightly. The last component, if any (i.e. C<X>) is
885simply ignored. This is predicated on the assumption that new features
886will not, in general, be added to maintenance releases. So C<:5.10>
887and C<:5.10.X> have identical effect. This is a change to the behaviour
888documented for 5.10.0.
3ab3a109 889
b6381718 890C<feature> now includes the C<unicode_strings> feature:
3ab3a109
JV
891
892 use feature "unicode_strings";
893
894This pragma turns on Unicode semantics for the case-changing operations
c66407fa
RS
895(C<uc>, C<lc>, C<ucfirst>, C<lcfirst>) on strings that don't have the
896internal UTF-8 flag set, but that contain single-byte characters between
897128 and 255.
3ab3a109 898
b7569deb 899Upgraded from version 1.11 to 1.16.
a56dbb5e
JV
900
901=item C<less>
902
903C<less> now includes the C<stash_name> method to allow subclasses of
904C<less> to pick where in %^H to store their stash.
905
906Upgraded from version 0.02 to 0.03.
907
908=item C<lib>
909
910Upgraded from version 0.5565 to 0.62.
911
912=item C<mro>
3ab3a109 913
702b4ef6
JV
914C<mro> is now implemented as an XS extension. The documented interface has
915not changed. Code relying on the implementation detail that some C<mro::>
b6381718 916methods happened to be available at all times gets to "keep both pieces".
3ab3a109 917
a56dbb5e 918Upgraded from version 1.00 to 1.02.
3ab3a109 919
a56dbb5e 920=item C<overload>
3ab3a109 921
b6381718 922C<overload> now allow overloading of 'qr'.
3ab3a109 923
a56dbb5e 924Upgraded from version 1.06 to 1.10.
3ab3a109 925
a56dbb5e 926=item C<threads>
3ab3a109 927
a56dbb5e 928Upgraded from version 1.67 to 1.75.
3ab3a109 929
a56dbb5e
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930=item C<threads::shared>
931
932Upgraded from version 1.14 to 1.32.
933
934=item C<version>
3ab3a109 935
702b4ef6
JV
936C<version> now has support for L</Version number formats> as described
937earlier in this document and in its own documentation.
3ab3a109 938
a56dbb5e
JV
939Upgraded from version 0.74 to 0.82.
940
941=item C<warnings>
942
943C<warnings> has a new C<warnings::fatal_enabled()> function. It also
944includes a new C<illegalproto> warning category. See also L</New or
945Changed Diagnostics> for this change.
3ab3a109 946
a56dbb5e 947Upgraded from version 1.06 to 1.09.
3ab3a109
JV
948
949=back
950
a56dbb5e
JV
951=head2 Updated Modules
952
953=over 4
954
955=item C<Archive::Extract>
956
957Upgraded from version 0.24 to 0.38.
958
959=item C<Archive::Tar>
960
961Upgraded from version 1.38 to 1.54.
962
963=item C<Attribute::Handlers>
964
965Upgraded from version 0.79 to 0.87.
966
967=item C<AutoLoader>
968
969Upgraded from version 5.63 to 5.70.
970
971=item C<B::Concise>
972
973Upgraded from version 0.74 to 0.78.
974
975=item C<B::Debug>
976
977Upgraded from version 1.05 to 1.12.
978
979=item C<B::Deparse>
980
702b4ef6 981Upgraded from version 0.83 to 0.96.
a56dbb5e
JV
982
983=item C<B::Lint>
984
985Upgraded from version 1.09 to 1.11_01.
986
987=item C<CGI>
988
989Upgraded from version 3.29 to 3.48.
990
991=item C<Class::ISA>
992
993Upgraded from version 0.33 to 0.36.
994
702b4ef6
JV
995NOTE: C<Class::ISA> is deprecated and may be removed from a future
996version of Perl.
a56dbb5e
JV
997
998=item C<Compress::Raw::Zlib>
999
1000Upgraded from version 2.008 to 2.024.
1001
1002=item C<CPAN>
1003
1004Upgraded from version 1.9205 to 1.94_56.
1005
1006=item C<CPANPLUS>
1007
1008Upgraded from version 0.84 to 0.90.
1009
1010=item C<CPANPLUS::Dist::Build>
1011
1012Upgraded from version 0.06_02 to 0.46.
1013
1014=item C<Data::Dumper>
1015
1016Upgraded from version 2.121_14 to 2.125.
1017
1018=item C<DB_File>
1019
1020Upgraded from version 1.816_1 to 1.820.
1021
1022=item C<Devel::PPPort>
1023
1024Upgraded from version 3.13 to 3.19.
1025
1026=item C<Digest>
1027
1028Upgraded from version 1.15 to 1.16.
1029
1030=item C<Digest::MD5>
1031
1032Upgraded from version 2.36_01 to 2.39.
1033
1034=item C<Digest::SHA>
1035
1036Upgraded from version 5.45 to 5.47.
1037
1038=item C<Encode>
1039
1040Upgraded from version 2.23 to 2.39.
1041
1042=item C<Exporter>
1043
1044Upgraded from version 5.62 to 5.64_01.
1045
1046=item C<ExtUtils::CBuilder>
1047
1048Upgraded from version 0.21 to 0.27.
1049
1050=item C<ExtUtils::Command>
1051
1052Upgraded from version 1.13 to 1.16.
1053
1054=item C<ExtUtils::Constant>
1055
1056Upgraded from version 0.2 to 0.22.
1057
1058=item C<ExtUtils::Install>
1059
1060Upgraded from version 1.44 to 1.55.
1061
1062=item C<ExtUtils::MakeMaker>
1063
1064Upgraded from version 6.42 to 6.56.
1065
1066=item C<ExtUtils::Manifest>
1067
1068Upgraded from version 1.51_01 to 1.57.
1069
1070=item C<ExtUtils::ParseXS>
1071
1072Upgraded from version 2.18_02 to 2.21.
1073
1074=item C<File::Fetch>
1075
1076Upgraded from version 0.14 to 0.24.
1077
1078=item C<File::Path>
1079
1080Upgraded from version 2.04 to 2.08_01.
1081
1082=item C<File::Temp>
1083
1084Upgraded from version 0.18 to 0.22.
1085
1086=item C<Filter::Simple>
1087
1088Upgraded from version 0.82 to 0.84.
1089
1090=item C<Filter::Util::Call>
1091
1092Upgraded from version 1.07 to 1.08.
1093
1094=item C<Getopt::Long>
1095
1096Upgraded from version 2.37 to 2.38.
1097
1098=item C<IO>
1099
1100Upgraded from version 1.23_01 to 1.25_02.
1101
1102=item C<IO::Zlib>
1103
1104Upgraded from version 1.07 to 1.10.
1105
1106=item C<IPC::Cmd>
1107
1108Upgraded from version 0.40_1 to 0.54.
1109
1110=item C<IPC::SysV>
1111
1112Upgraded from version 1.05 to 2.01.
1113
1114=item C<Locale::Maketext>
1115
1116Upgraded from version 1.12 to 1.14.
1117
1118=item C<Locale::Maketext::Simple>
1119
1120Upgraded from version 0.18 to 0.21.
1121
1122=item C<Log::Message>
1123
1124Upgraded from version 0.01 to 0.02.
1125
1126=item C<Log::Message::Simple>
1127
1128Upgraded from version 0.04 to 0.06.
1129
1130=item C<Math::BigInt>
1131
1132Upgraded from version 1.88 to 1.89_01.
1133
1134=item C<Math::BigInt::FastCalc>
1135
1136Upgraded from version 0.16 to 0.19.
1137
1138=item C<Math::BigRat>
1139
1140Upgraded from version 0.21 to 0.24.
1141
1142=item C<Math::Complex>
1143
1144Upgraded from version 1.37 to 1.56.
1145
1146=item C<Memoize>
1147
1148Upgraded from version 1.01_02 to 1.01_03.
1149
1150=item C<MIME::Base64>
1151
1152Upgraded from version 3.07_01 to 3.08.
1153
1154=item C<Module::Build>
1155
1156Upgraded from version 0.2808_01 to 0.3603.
1157
1158=item C<Module::CoreList>
1159
702b4ef6 1160Upgraded from version 2.12 to 2.29.
a56dbb5e
JV
1161
1162=item C<Module::Load>
1163
1164Upgraded from version 0.12 to 0.16.
1165
1166=item C<Module::Load::Conditional>
1167
1168Upgraded from version 0.22 to 0.34.
1169
1170=item C<Module::Loaded>
1171
1172Upgraded from version 0.01 to 0.06.
1173
1174=item C<Module::Pluggable>
1175
1176Upgraded from version 3.6 to 3.9.
1177
1178=item C<Net::Ping>
1179
1180Upgraded from version 2.33 to 2.36.
1181
1182=item C<NEXT>
1183
1184Upgraded from version 0.60_01 to 0.64.
1185
1186=item C<Object::Accessor>
1187
1188Upgraded from version 0.32 to 0.36.
1189
1190=item C<Package::Constants>
1191
1192Upgraded from version 0.01 to 0.02.
1193
1194=item C<PerlIO>
1195
1196Upgraded from version 1.04 to 1.06.
1197
1198=item C<Pod::Parser>
1199
1200Upgraded from version 1.35 to 1.37.
1201
1202=item C<Pod::Perldoc>
1203
1204Upgraded from version 3.14_02 to 3.15_02.
1205
1206=item C<Pod::Plainer>
1207
1208Upgraded from version 0.01 to 1.02.
1209
702b4ef6
JV
1210NOTE: C<Pod::Plainer> is deprecated and may be removed from a future
1211version of Perl.
a56dbb5e
JV
1212
1213=item C<Pod::Simple>
1214
1215Upgraded from version 3.05 to 3.13.
1216
1217=item C<Safe>
1218
1219Upgraded from version 2.12 to 2.22.
1220
1221=item C<SelfLoader>
1222
1223Upgraded from version 1.11 to 1.17.
1224
1225=item C<Storable>
1226
1227Upgraded from version 2.18 to 2.22.
1228
1229=item C<Switch>
1230
1231Upgraded from version 2.13 to 2.16.
1232
702b4ef6
JV
1233NOTE: C<Switch> is deprecated and may be removed from a future version
1234of Perl.
a56dbb5e
JV
1235
1236=item C<Sys::Syslog>
1237
1238Upgraded from version 0.22 to 0.27.
1239
1240=item C<Term::ANSIColor>
1241
1242Upgraded from version 1.12 to 2.02.
1243
1244=item C<Term::UI>
1245
1246Upgraded from version 0.18 to 0.20.
1247
1248=item C<Test>
1249
1250Upgraded from version 1.25 to 1.25_02.
1251
1252=item C<Test::Harness>
1253
1254Upgraded from version 2.64 to 3.17.
1255
1256=item C<Test::Simple>
1257
1258Upgraded from version 0.72 to 0.94.
1259
1260=item C<Text::Balanced>
1261
1262Upgraded from version 2.0.0 to 2.02.
1263
1264=item C<Text::ParseWords>
1265
1266Upgraded from version 3.26 to 3.27.
1267
1268=item C<Text::Soundex>
1269
1270Upgraded from version 3.03 to 3.03_01.
1271
1272=item C<Thread::Queue>
1273
1274Upgraded from version 2.00 to 2.11.
1275
1276=item C<Thread::Semaphore>
1277
1278Upgraded from version 2.01 to 2.09.
1279
1280=item C<Tie::RefHash>
1281
1282Upgraded from version 1.37 to 1.38.
1283
1284=item C<Time::HiRes>
1285
1286Upgraded from version 1.9711 to 1.9719.
1287
1288=item C<Time::Local>
1289
1290Upgraded from version 1.18 to 1.1901_01.
1291
1292=item C<Time::Piece>
1293
1294Upgraded from version 1.12 to 1.15.
1295
1296=item C<Unicode::Collate>
1297
1298Upgraded from version 0.52 to 0.52_01.
1299
1300=item C<Unicode::Normalize>
1301
1302Upgraded from version 1.02 to 1.03.
1303
1304=item C<Win32>
1305
1306Upgraded from version 0.34 to 0.39.
1307
1308=item C<Win32API::File>
1309
1310Upgraded from version 0.1001_01 to 0.1101.
1311
1312=item C<XSLoader>
1313
1314Upgraded from version 0.08 to 0.10.
1315
1316=back
3ab3a109 1317
b6381718 1318=head2 Removed Modules and Pragmata
3ab3a109
JV
1319
1320=over 4
1321
a56dbb5e 1322=item C<attrs>
3ab3a109 1323
a56dbb5e 1324Removed from the Perl core. Prior version was 1.02.
3ab3a109 1325
a56dbb5e 1326=item C<CPAN::API::HOWTO>
3ab3a109 1327
a56dbb5e
JV
1328Removed from the Perl core. Prior version was 'undef'.
1329
1330=item C<CPAN::DeferedCode>
1331
1332Removed from the Perl core. Prior version was 5.50.
1333
1334=item C<CPANPLUS::inc>
1335
1336Removed from the Perl core. Prior version was 'undef'.
1337
1338=item C<DCLsym>
1339
1340Removed from the Perl core. Prior version was 1.03.
1341
1342=item C<ExtUtils::MakeMaker::bytes>
1343
1344Removed from the Perl core. Prior version was 6.42.
1345
1346=item C<ExtUtils::MakeMaker::vmsish>
1347
1348Removed from the Perl core. Prior version was 6.42.
3ab3a109 1349
a56dbb5e
JV
1350=item C<Stdio>
1351
1352Removed from the Perl core. Prior version was 2.3.
1353
1354=item C<Test::Harness::Assert>
1355
1356Removed from the Perl core. Prior version was 0.02.
1357
1358=item C<Test::Harness::Iterator>
1359
1360Removed from the Perl core. Prior version was 0.02.
1361
1362=item C<Test::Harness::Point>
1363
1364Removed from the Perl core. Prior version was 0.01.
1365
1366=item C<Test::Harness::Results>
1367
1368Removed from the Perl core. Prior version was 0.01.
1369
1370=item C<Test::Harness::Straps>
1371
1372Removed from the Perl core. Prior version was 0.26_01.
1373
1374=item C<Test::Harness::Util>
1375
1376Removed from the Perl core. Prior version was 0.01.
1377
1378=item C<XSSymSet>
1379
1380Removed from the Perl core. Prior version was 1.1.
3ab3a109
JV
1381
1382=back
1383
b6381718
JV
1384=head2 Deprecated Modules and Pragmata
1385
1386See L</Deprecated Modules> above.
1387
a56dbb5e 1388
3ab3a109
JV
1389=head1 Documentation
1390
1391=head2 New Documentation
1392
1393=over 4
1394
1395=item *
1396
702b4ef6
JV
1397L<perlhaiku> contains instructions on how to build perl for the Haiku
1398platform.
3ab3a109
JV
1399
1400=item *
1401
702b4ef6
JV
1402L<perlmroapi> describes the new interface for pluggable Method Resolution
1403Orders.
3ab3a109
JV
1404
1405=item *
1406
b6381718 1407L<perlperf>, by Richard Foley, provides an introduction to the use of
3ab3a109
JV
1408performance and optimization techniques which can be used with particular
1409reference to perl programs.
1410
1411=item *
1412
702b4ef6
JV
1413L<perlrepository> describes how to access the perl source using the I<git>
1414version control system.
3ab3a109
JV
1415
1416=item *
1417
1418L<perlpolicy> extends the "Social contract about contributed modules" into
1419the beginnings of a document on Perl porting policies.
1420
1421=back
1422
1423=head2 Changes to Existing Documentation
1424
b6381718 1425
72d4e865
JV
1426=over
1427
1428
1429=item *
1430
702b4ef6
JV
1431The various large F<Changes*> files (which listed every change made
1432to perl over the last 18 years) have been removed, and replaced by a
1433small file, also called F<Changes>, which just explains how that same
1434information may be extracted from the git version control system.
3ab3a109 1435
72d4e865
JV
1436=item *
1437
b6381718 1438F<Porting/patching.pod> has been deleted, as it mainly described
3ab3a109
JV
1439interacting with the old Perforce-based repository, which is now obsolete.
1440Information still relevant has been moved to L<perlrepository>.
1441
3ab3a109 1442
72d4e865
JV
1443=item *
1444
702b4ef6
JV
1445The syntax C<unless (EXPR) BLOCK else BLOCK> is now documented as valid,
1446as is the syntax C<unless (EXPR) BLOCK elsif (EXPR) BLOCK ... else
1447BLOCK>, although actually using the latter may not be the best idea for
1448the readability of your source code.
72d4e865 1449
3ab3a109
JV
1450
1451=item *
1452
1453Documented -X overloading.
1454
1455=item *
1456
1457Documented that C<when()> treats specially most of the filetest operators
1458
1459=item *
1460
b6381718 1461Documented C<when> as a syntax modifier.
3ab3a109
JV
1462
1463=item *
1464
c66407fa 1465Eliminated "Old Perl threads tutorial", which described 5005 threads.
3ab3a109
JV
1466
1467F<pod/perlthrtut.pod> is the same material reworked for ithreads.
1468
1469=item *
1470
1471Correct previous documentation: v-strings are not deprecated
1472
72d4e865 1473With version objects, we need them to use MODULE VERSION syntax. This
c66407fa 1474patch removes the deprecation notice.
3ab3a109
JV
1475
1476=item *
1477
b6381718
JV
1478Security contact information is now part of L<perlsec>.
1479
1480=item *
3ab3a109 1481
702b4ef6
JV
1482A significant fraction of the core documentation has been updated to
1483clarify the behavior of Perl's Unicode handling.
3ab3a109
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1484
1485Much of the remaining core documentation has been reviewed and edited
1486for clarity, consistent use of language, and to fix the spelling of Tom
1487Christiansen's name.
1488
b6381718
JV
1489=item *
1490
3ab3a109 1491The Pod specification (L<perlpodspec>) has been updated to bring the
c66407fa 1492specification in line with modern usage already supported by most Pod
72d4e865
JV
1493systems. A parameter string may now follow the format name in a
1494"begin/end" region. Links to URIs with a text description are now
1495allowed. The usage of C<LE<lt>"section"E<gt>> has been marked as
c66407fa 1496deprecated.
3ab3a109 1497
b6381718
JV
1498=item *
1499
3ab3a109 1500L<if.pm|if> has been documented in L<perlfunc/use> as a means to get
c66407fa
RS
1501conditional loading of modules despite the implicit BEGIN block around
1502C<use>.
3ab3a109
JV
1503
1504=item *
1505
c66407fa 1506The documentation for C<$1> in perlvar.pod has been clarified.
3ab3a109 1507
a620a577
KW
1508=item *
1509
1510C<\N{U+I<wide hex char>}> is now documented.
1511
3ab3a109
JV
1512=back
1513
b6381718 1514=head1 Selected Performance Enhancements
3ab3a109
JV
1515
1516=over 4
1517
1518=item *
1519
1520A new internal cache means that C<isa()> will often be faster.
1521
1522=item *
1523
702b4ef6
JV
1524The implementation of C<C3> Method Resolution Order has been
1525optimised - linearisation for classes with single inheritance is 40%
1526faster. Performance for multiple inheritance is unchanged.
3ab3a109
JV
1527
1528=item *
1529
1530Under C<use locale>, the locale-relevant information is now cached on
1531read-only values, such as the list returned by C<keys %hash>. This makes
702b4ef6
JV
1532operations such as C<sort keys %hash> in the scope of C<use locale>
1533much faster.
3ab3a109
JV
1534
1535=item *
1536
1537Empty C<DESTROY> methods are no longer called.
1538
1539=item *
1540
b6381718 1541C<Perl_sv_utf8_upgrade()> is now faster.
3ab3a109
JV
1542
1543=item *
1544
b6381718 1545C<keys> on empty hash is now faster.
3ab3a109
JV
1546
1547=item *
1548
b6381718 1549C<if (%foo)> has been optimized to be faster than C<if (keys %foo)>.
3ab3a109
JV
1550
1551=item *
1552
702b4ef6
JV
1553The string repetition operator (C<$str x $num>) is now several times
1554faster when C<$str> has length one or C<$num> is large.
8a4f3f14
VP
1555
1556=item *
1557
3ab3a109 1558Reversing an array to itself (as in C<@a = reverse @a>) in void context
702b4ef6
JV
1559now happens in-place and is several orders of magnitude faster than
1560it used to be. It will also preserve non-existent elements whenever
1561possible, i.e. for non magical arrays or tied arrays with C<EXISTS>
1562and C<DELETE> methods.
3ab3a109
JV
1563
1564=back
1565
1566=head1 Installation and Configuration Improvements
1567
72d4e865
JV
1568=over 4
1569
1570=item *
1571
1572L<perlapi>, L<perlintern>, L<perlmodlib> and L<perltoc> are now all
1573generated at build time, rather than being shipped as part of the release.
1574
1575=item *
3ab3a109 1576
702b4ef6
JV
1577If C<vendorlib> and C<vendorarch> are the same, then they are only added
1578to C<@INC> once.
3ab3a109 1579
72d4e865
JV
1580=item *
1581
3ab3a109
JV
1582C<$Config{usedevel}> and the C-level C<PERL_USE_DEVEL> are now defined if
1583perl is built with C<-Dusedevel>.
1584
72d4e865
JV
1585=item *
1586
3ab3a109
JV
1587F<Configure> will enable use of C<-fstack-protector>, to provide protection
1588against stack-smashing attacks, if the compiler supports it.
1589
72d4e865
JV
1590=item *
1591
3ab3a109 1592F<Configure> will now determine the correct prototypes for re-entrant
c66407fa 1593functions and for C<gconvert> if you are using a C++ compiler rather
3ab3a109
JV
1594than a C compiler.
1595
72d4e865
JV
1596=item *
1597
3ab3a109
JV
1598On Unix, if you build from a tree containing a git repository, the
1599configuration process will note the commit hash you have checked out, for
1600display in the output of C<perl -v> and C<perl -V>. Unpushed local commits
1601are automatically added to the list of local patches displayed by
1602C<perl -V>.
1603
72d4e865
JV
1604=item *
1605
b6381718 1606Perl now supports SystemTap's C<dtrace> compatibility layer and an
72d4e865
JV
1607issue with linking C<miniperl> has been fixed in the process.
1608
1609=item *
1610
b6381718
JV
1611perldoc now uses C<less -R> instead of C<less> for improved behaviour
1612in the face of C<groff>'s new usage of ANSI escape codes.
72d4e865
JV
1613
1614=item *
1615
72d4e865 1616
b6381718
JV
1617C<perl -V> now reports use of the compile-time options C<USE_PERL_ATOF> and
1618C<USE_ATTRIBUTES_FOR_PERLIO>.
72d4e865 1619
b6381718 1620=item *
3ab3a109
JV
1621
1622As part of the flattening of F<ext>, all extensions on all platforms are
1623built by F<make_ext.pl>. This replaces the Unix-specific
1624F<ext/util/make_ext>, VMS-specific F<make_ext.com> and Win32-specific
1625F<win32/buildext.pl>.
1626
b6381718 1627=back
3ab3a109 1628
b6381718
JV
1629=head1 Internal Changes
1630
1631Each release of Perl sees numerous internal changes which shouldn't
1632affect day to day usage but may still be notable for developers working
1633with Perl's source code.
1634
1635=over
3ab3a109
JV
1636
1637=item *
1638
702b4ef6
JV
1639The J.R.R. Tolkien quotes at the head of C source file have been checked
1640and proper citations added, thanks to a patch from Tom Christiansen.
3ab3a109
JV
1641
1642=item *
1643
b6381718 1644The internal structure of the dual-life modules traditionally found in
e706c0cd 1645the F<lib/> and F<ext/> directories in the perl source has changed
b6381718
JV
1646significantly. Where possible, dual-lifed modules have been extracted
1647from F<lib/> and F<ext/>.
1648
1649Dual-lifed modules maintained by Perl's developers as part of the Perl
1650core now live in F<dist/>. Dual-lifed modules maintained primarily on
1651CPAN now live in F<cpan/>. When reporting a bug in a module located
1652under F<cpan/>, please send your bug report directly to the module's
1653bug tracker or author, rather than Perl's bug tracker.
3ab3a109
JV
1654
1655=item *
1656
b6381718
JV
1657C<\N{...}> now compiles better, always forces UTF-8 internal representation
1658
702b4ef6
JV
1659Perl's developers have fixed several problems with the recognition of
1660C<\N{...}> constructs. As part of this, perl will store any scalar
1661or regex containing C<\N{I<name>}> or C<\N{U+I<wide hex char>}> in its
1662definition in UTF-8 format. (This was true previously for all occurences
1663of C<\N{I<name>}> that did not use a custom translator, but now it's
1664always true.)
3ab3a109
JV
1665
1666=item *
1667
b6381718 1668Perl_magic_setmglob now knows about globs, fixing RT #71254.
3ab3a109
JV
1669
1670=item *
1671
b6381718 1672C<SVt_RV> no longer exists. RVs are now stored in IVs.
3ab3a109
JV
1673
1674=item *
1675
702b4ef6
JV
1676C<Perl_vcroak()> now accepts a null first argument. In addition, a full
1677audit was made of the "not NULL" compiler annotations, and those for
1678several other internal functions were corrected.
3ab3a109
JV
1679
1680=item *
1681
1682New macros C<dSAVEDERRNO>, C<dSAVE_ERRNO>, C<SAVE_ERRNO>, C<RESTORE_ERRNO>
1683have been added to formalise the temporary saving of the C<errno>
1684variable.
1685
1686=item *
1687
1688The function C<Perl_sv_insert_flags> has been added to augment
1689C<Perl_sv_insert>.
1690
1691=item *
1692
1693The function C<Perl_newSV_type(type)> has been added, equivalent to
1694C<Perl_newSV()> followed by C<Perl_sv_upgrade(type)>.
1695
1696=item *
1697
1698The function C<Perl_newSVpvn_flags()> has been added, equivalent to
1699C<Perl_newSVpvn()> and then performing the action relevant to the flag.
1700
1701Two flag bits are currently supported.
1702
1703=over 4
1704
1705=item *
1706
702b4ef6
JV
1707C<SVf_UTF8> will call C<SvUTF8_on()> for you. (Note that this does
1708not convert an sequence of ISO 8859-1 characters to UTF-8). A wrapper,
1709C<newSVpvn_utf8()> is available for this.
3ab3a109
JV
1710
1711=item *
1712
b6381718 1713C<SVs_TEMP> now calls C<Perl_sv_2mortal()> on the new SV.
3ab3a109
JV
1714
1715=back
1716
1717There is also a wrapper that takes constant strings, C<newSVpvs_flags()>.
1718
1719=item *
1720
1721The function C<Perl_croak_xs_usage> has been added as a wrapper to
1722C<Perl_croak>.
1723
1724=item *
1725
b6381718 1726Perl now exports the functions C<PerlIO_find_layer> and C<PerlIO_list_alloc>.
3ab3a109
JV
1727
1728=item *
1729
702b4ef6
JV
1730C<PL_na> has been exterminated from the core code, replaced by local
1731STRLEN temporaries, or C<*_nolen()> calls. Either approach is faster than
1732C<PL_na>, which is a pointer dereference into the interpreter structure
1733under ithreads, and a global variable otherwise.
3ab3a109
JV
1734
1735=item *
1736
702b4ef6
JV
1737C<Perl_mg_free()> used to leave freed memory accessible via C<SvMAGIC()>
1738on the scalar. It now updates the linked list to remove each piece of
1739magic as it is freed.
3ab3a109
JV
1740
1741=item *
1742
702b4ef6
JV
1743Under ithreads, the regex in C<PL_reg_curpm> is now reference
1744counted. This eliminates a lot of hackish workarounds to cope with it
1745not being reference counted.
3ab3a109
JV
1746
1747=item *
1748
1749C<Perl_mg_magical()> would sometimes incorrectly turn on C<SvRMAGICAL()>.
1750This has been fixed.
1751
1752=item *
1753
1754The I<public> IV and NV flags are now not set if the string value has
1755trailing "garbage". This behaviour is consistent with not setting the
1756public IV or NV flags if the value is out of range for the type.
1757
1758=item *
1759
702b4ef6
JV
1760Uses of C<Nullav>, C<Nullcv>, C<Nullhv>, C<Nullop>, C<Nullsv> etc have
1761been replaced by C<NULL> in the core code, and non-dual-life modules,
1762as C<NULL> is clearer to those unfamiliar with the core code.
3ab3a109
JV
1763
1764=item *
1765
1766A macro C<MUTABLE_PTR(p)> has been added, which on (non-pedantic) gcc will
1767not cast away C<const>, returning a C<void *>. Macros C<MUTABLE_SV(av)>,
1768C<MUTABLE_SV(cv)> etc build on this, casting to C<AV *> etc without
1769casting away C<const>. This allows proper compile-time auditing of
702b4ef6
JV
1770C<const> correctness in the core, and helped picked up some errors
1771(now fixed).
3ab3a109
JV
1772
1773=item *
1774
1775Macros C<mPUSHs()> and C<mXPUSHs()> have been added, for pushing SVs on the
1776stack and mortalizing them.
1777
1778=item *
1779
1780Use of the private structure C<mro_meta> has changed slightly. Nothing
1781outside the core should be accessing this directly anyway.
1782
b6381718
JV
1783=item *
1784
1785A new tool, F<Porting/expand-macro.pl> has been added, that allows you
1786to view how a C preprocessor macro would be expanded when compiled.
1787This is handy when trying to decode the macro hell that is the perl
1788guts.
1789
1790=back
1791
1792=head1 Testing
1793
1794=head2 Testing improvements
1795
1796=over 4
1797
1798=item Parallel tests
1799
1800The core distribution can now run its regression tests in parallel on
1801Unix-like platforms. Instead of running C<make test>, set C<TEST_JOBS> in
1802your environment to the number of tests to run in parallel, and run
1803C<make test_harness>. On a Bourne-like shell, this can be done as
1804
1805 TEST_JOBS=3 make test_harness # Run 3 tests in parallel
3ab3a109 1806
b6381718
JV
1807An environment variable is used, rather than parallel make itself, because
1808L<TAP::Harness> needs to be able to schedule individual non-conflicting test
1809scripts itself, and there is no standard interface to C<make> utilities to
1810interact with their job schedulers.
3ab3a109 1811
b6381718
JV
1812Note that currently some test scripts may fail when run in parallel (most
1813notably C<ext/IO/t/io_dir.t>). If necessary run just the failing scripts
1814again sequentially and see if the failures go away.
3ab3a109 1815
b6381718 1816=item Test harness flexibility
3ab3a109 1817
b6381718
JV
1818It's now possible to override C<PERL5OPT> and friends in F<t/TEST>
1819
1820=item Test watchdog
3ab3a109 1821
3ab3a109
JV
1822Several tests that have the potential to hang forever if they fail now
1823incorporate a "watchdog" functionality that will kill them after a timeout,
1824which helps ensure that C<make test> and C<make test_harness> run to
79849ba8 1825completion automatically.
3ab3a109 1826
b6381718
JV
1827
1828=back
1829
1830=head2 New Tests
1831
1832Perl's developers have added a number of new tests to the core.
1833In addition to the items listed below, many modules updated from CPAN
1834incorporate new tests.
3ab3a109
JV
1835
1836=over 4
1837
1838=item *
1839
1840Significant cleanups to core tests to ensure that language and
1841interpreter features are not used before they're tested.
1842
1843=item *
1844
c66407fa
RS
1845C<make test_porting> now runs a number of important pre-commit checks
1846which might be of use to anyone working on the Perl core.
3ab3a109
JV
1847
1848=item *
1849
1850F<t/porting/podcheck.t> automatically checks the well-formedness of
1851POD found in all .pl, .pm and .pod files in the F<MANIFEST>, other than in
1852dual-lifed modules which are primarily maintained outside the Perl core.
1853
1854=item *
1855
702b4ef6
JV
1856F<t/porting/manifest.t> now tests that all files listed in MANIFEST
1857are present.
3ab3a109
JV
1858
1859=item *
1860
b6381718 1861F<t/op/while_readdir.t> tests that a bare readdir in while loop sets $_.
3ab3a109
JV
1862
1863=item *
1864
702b4ef6
JV
1865F<t/comp/retainedlines.t> checks that the debugger can retain source
1866lines from C<eval>.
3ab3a109
JV
1867
1868=item *
1869
b6381718 1870F<t/io/perlio_fail.t> checks that bad layers fail.
3ab3a109
JV
1871
1872=item *
1873
b6381718 1874F<t/io/perlio_leaks.t> checks that PerlIO layers are not leaking.
3ab3a109
JV
1875
1876=item *
1877
b6381718 1878F<t/io/perlio_open.t> checks that certain special forms of open work.
3ab3a109
JV
1879
1880=item *
1881
b6381718 1882F<t/io/perlio.t> includes general PerlIO tests.
3ab3a109
JV
1883
1884=item *
1885
702b4ef6
JV
1886F<t/io/pvbm.t> checks that there is no unexpected interaction between
1887the internal types C<PVBM> and C<PVGV>.
3ab3a109
JV
1888
1889=item *
1890
702b4ef6
JV
1891F<t/mro/package_aliases.t> checks that mro works properly in the presence
1892of aliased packages.
3ab3a109
JV
1893
1894=item *
1895
b6381718 1896F<t/op/dbm.t> tests C<dbmopen> and C<dbmclose>.
3ab3a109
JV
1897
1898=item *
1899
b6381718 1900F<t/op/index_thr.t> tests the interaction of C<index> and threads.
3ab3a109
JV
1901
1902=item *
1903
b6381718 1904F<t/op/pat_thr.t> tests the interaction of esoteric patterns and threads.
3ab3a109
JV
1905
1906=item *
1907
b6381718 1908F<t/op/qr_gc.t> tests that C<qr> doesn't leak.
3ab3a109
JV
1909
1910=item *
1911
b6381718 1912F<t/op/reg_email_thr.t> tests the interaction of regex recursion and threads.
3ab3a109
JV
1913
1914=item *
1915
702b4ef6
JV
1916F<t/op/regexp_qr_embed_thr.t> tests the interaction of patterns with
1917embedded C<qr//> and threads.
3ab3a109
JV
1918
1919=item *
1920
702b4ef6
JV
1921F<t/op/regexp_unicode_prop.t> tests Unicode properties in regular
1922expressions.
3ab3a109
JV
1923
1924=item *
1925
702b4ef6
JV
1926F<t/op/regexp_unicode_prop_thr.t> tests the interaction of Unicode
1927properties and threads.
3ab3a109
JV
1928
1929=item *
1930
b6381718 1931F<t/op/reg_nc_tie.t> tests the tied methods of C<Tie::Hash::NamedCapture>.
3ab3a109
JV
1932
1933=item *
1934
702b4ef6
JV
1935F<t/op/reg_posixcc.t> checks that POSIX character classes behave
1936consistently.
3ab3a109
JV
1937
1938=item *
1939
0c359e6f 1940F<t/op/re.t> checks that exportable C<re> functions in F<universal.c> work.
3ab3a109
JV
1941
1942=item *
1943
b6381718 1944F<t/op/setpgrpstack.t> checks that C<setpgrp> works.
3ab3a109
JV
1945
1946=item *
1947
b6381718 1948F<t/op/substr_thr.t> tests the interaction of C<substr> and threads.
3ab3a109
JV
1949
1950=item *
1951
b6381718 1952F<t/op/upgrade.t> checks that upgrading and assigning scalars works.
3ab3a109
JV
1953
1954=item *
1955
b6381718 1956F<t/uni/lex_utf8.t> checks that Unicode in the lexer works.
3ab3a109
JV
1957
1958=item *
1959
b6381718 1960F<t/uni/tie.t> checks that Unicode and C<tie> work.
3ab3a109
JV
1961
1962=item *
1963
b6381718 1964F<t/comp/final_line_num.t> tests whether line numbers are correct at EOF
3ab3a109
JV
1965
1966=item *
1967
b6381718 1968F<t/comp/form_scope.t> tests format scoping.
3ab3a109
JV
1969
1970=item *
1971
b6381718 1972F<t/comp/line_debug.t> tests whether C<< @{"_<$file"} >> works.
3ab3a109
JV
1973
1974=item *
1975
b6381718 1976F<t/op/filetest_t.t> tests if -t file test works.
3ab3a109
JV
1977
1978=item *
1979
b6381718 1980F<t/op/qr.t> tests C<qr>.
3ab3a109
JV
1981
1982=item *
1983
b6381718 1984F<t/op/utf8cache.t> tests malfunctions of the utf8 cache.
3ab3a109
JV
1985
1986=item *
1987
b6381718 1988F<t/re/uniprops.t> test unicodes C<\p{}> regex constructs.
3ab3a109 1989
b16f1257
JV
1990=item *
1991
b6381718
JV
1992F<t/op/filehandle.t> tests some suitably portable filetest operators
1993to check that they work as expected, particularly in the light of some
1994internal changes made in how filehandles are blessed.
72d4e865 1995
b16f1257
JV
1996=item *
1997
b6381718
JV
1998F<t/op/time_loop.t> tests that unix times greater than C<2**63>, which
1999can now be handed to C<gmtime> and C<localtime>, do not cause an internal
2000overflow or an excessively long loop.
72d4e865 2001
3ab3a109
JV
2002=back
2003
3ab3a109 2004
b6381718 2005=head1 New or Changed Diagnostics
72d4e865 2006
b6381718 2007=head2 New Diagnostics
72d4e865 2008
b6381718 2009=over
72d4e865 2010
b6381718 2011=item *
72d4e865 2012
b6381718
JV
2013SV allocation tracing has been added to the diagnostics enabled by C<-Dm>.
2014The tracing can alternatively output via the C<PERL_MEM_LOG> mechanism, if
2015that was enabled when the F<perl> binary was compiled.
72d4e865 2016
b6381718 2017=item *
3ab3a109 2018
702b4ef6
JV
2019Smartmatch resolution tracing has been added as a new diagnostic. Use
2020C<-DM> to enable it.
3ab3a109 2021
b6381718 2022=item *
3ab3a109 2023
b6381718
JV
2024A new debugging flag C<-DB> now dumps subroutine definitions, leaving
2025C<-Dx> for its original purpose of dumping syntax trees.
3ab3a109 2026
b6381718 2027=item *
3ab3a109 2028
b6381718
JV
2029Perl 5.12 provides a number of new diagnostic messages to help you write
2030better code. See L<perldiag> for details of these new messages.
3ab3a109
JV
2031
2032=over 4
2033
2034=item *
2035
2036C<Bad plugin affecting keyword '%s'>
2037
2038=item *
2039
2040C<gmtime(%.0f) too large>
2041
2042=item *
2043
2044C<Lexing code attempted to stuff non-Latin-1 character into Latin-1 input>
2045
2046=item *
2047
2048C<Lexing code internal error (%s)>
2049
2050=item *
2051
2052C<localtime(%.0f) too large>
2053
2054=item *
2055
2056C<Overloaded dereference did not return a reference>
2057
2058=item *
2059
2060C<Overloaded qr did not return a REGEXP>
2061
2062=item *
2063
2064C<Perl_pmflag() is deprecated, and will be removed from the XS API>
2065
2066=item *
2067
b6381718 2068C<lvalue attribute ignored after the subroutine has been defined>
3ab3a109
JV
2069
2070This new warning is issued when one attempts to mark a subroutine as
2071lvalue after it has been defined.
2072
2073=item *
2074
702b4ef6
JV
2075Perl now warns you if C<++> or C<--> are unable to change the value
2076because it's beyond the limit of representation.
3ab3a109
JV
2077
2078This uses a new warnings category: "imprecision".
2079
208f012a 2080=item *
c66407fa
RS
2081
2082C<lc>, C<uc>, C<lcfirst>, and C<ucfirst> warn when passed undef.
3ab3a109
JV
2083
2084=item *
2085
b6381718 2086C<Show constant in "Useless use of a constant in void context">
3ab3a109
JV
2087
2088=item *
2089
b6381718 2090C<Prototype after '%s'>
3ab3a109
JV
2091
2092=item *
2093
b6381718
JV
2094C<panic: sv_chop %s>
2095
2096This new fatal error occurs when the C routine C<Perl_sv_chop()> was
2097passed a position that is not within the scalar's string buffer. This
2098could be caused by buggy XS code, and at this point recovery is not
2099possible.
2100
3ab3a109
JV
2101
2102=item *
2103
b6381718
JV
2104The fatal error C<Malformed UTF-8 returned by \N> is now produced if the
2105C<charnames> handler returns malformed UTF-8.
3ab3a109
JV
2106
2107=item *
2108
702b4ef6
JV
2109If an unresolved named character or sequence was encountered when
2110compiling a regex pattern then the fatal error C<\N{NAME} must be resolved
2111by the lexer> is now produced. This can happen, for example, when using a
2112single-quotish context like C<$re = '\N{SPACE}'; /$re/;>. See L<perldiag>
2113for more examples of how the lexer can get bypassed.
3ab3a109
JV
2114
2115=item *
2116
702b4ef6
JV
2117C<Invalid hexadecimal number in \N{U+...}> is a new fatal error
2118triggered when the character constant represented by C<...> is not a
2119valid hexadecimal number.
3ab3a109
JV
2120
2121=item *
2122
b6381718 2123The new meaning of C<\N> as C<[^\n]> is not valid in a bracketed character
702b4ef6
JV
2124class, just like C<.> in a character class loses its special meaning,
2125and will cause the fatal error C<\N in a character class must be a named
2126character: \N{...}>.
b6381718
JV
2127
2128=item *
3ab3a109 2129
702b4ef6
JV
2130The rules on what is legal for the C<...> in C<\N{...}> have been
2131tightened up so that unless the C<...> begins with an alphabetic
2132character and continues with a combination of alphanumerics, dashes,
2133spaces, parentheses or colons then the warning C<Deprecated character(s)
2134in \N{...} starting at '%s'> is now issued.
3ab3a109
JV
2135
2136=item *
2137
702b4ef6
JV
2138The warning C<Using just the first characters returned by \N{}> will
2139be issued if the C<charnames> handler returns a sequence of characters
2140which exceeds the limit of the number of characters that can be used. The
2141message will indicate which characters were used and which were discarded.
3ab3a109 2142
b6381718 2143=back
3ab3a109 2144
b6381718 2145=back
3ab3a109 2146
b6381718 2147=head2 Changed Diagnostics
3ab3a109 2148
b6381718 2149A number of existing diagnostic messages have been improved or corrected:
3ab3a109 2150
b6381718 2151=over
3ab3a109
JV
2152
2153=item *
2154
b6381718
JV
2155A new warning category C<illegalproto> allows finer-grained control of
2156warnings around function prototypes.
3ab3a109 2157
b6381718 2158The two warnings:
3ab3a109 2159
b6381718 2160=over
3ab3a109 2161
b6381718
JV
2162=item C<Illegal character in prototype for %s : %s>
2163
2164=item C<Prototype after '%c' for %s : %s>
2165
2166=back
2167
2168have been moved from the C<syntax> top-level warnings category into a new
702b4ef6
JV
2169first-level category, C<illegalproto>. These two warnings are currently
2170the only ones emitted during parsing of an invalid/illegal prototype,
2171so one can now use
b6381718
JV
2172
2173 no warnings 'illegalproto';
2174
702b4ef6
JV
2175to suppress only those, but not other syntax-related warnings. Warnings
2176where prototypes are changed, ignored, or not met are still in the
2177C<prototype> category as before.
3ab3a109
JV
2178
2179=item *
2180
3ab3a109
JV
2181C<Deep recursion on subroutine "%s">
2182
2183It is now possible to change the depth threshold for this warning from the
2184default of 100, by recompiling the F<perl> binary, setting the C
2185pre-processor macro C<PERL_SUB_DEPTH_WARN> to the desired value.
2186
2187=item *
2188
b6381718
JV
2189C<Illegal character in prototype> warning is now more precise
2190when reporting illegal characters after _
3ab3a109
JV
2191
2192=item *
2193
702b4ef6
JV
2194mro merging error messages are now very similar to those produced by
2195L<Algorithm::C3>.
3ab3a109
JV
2196
2197=item *
2198
b6381718
JV
2199Amelioration of the error message "Unrecognized character %s in column %d"
2200
2201Changes the error message to "Unrecognized character %s; marked by E<lt>--
2202HERE after %sE<lt>-- HERE near column %d". This should make it a little
2203simpler to spot and correct the suspicious character.
3ab3a109
JV
2204
2205=item *
2206
702b4ef6
JV
2207Perl now explicitly points to C<$.> when it causes an uninitialized
2208warning for ranges in scalar context.
3ab3a109
JV
2209
2210=item *
2211
b6381718 2212C<split> now warns when called in void context.
3ab3a109
JV
2213
2214=item *
2215
b6381718
JV
2216C<printf>-style functions called with too few arguments will now issue the
2217warning C<"Missing argument in %s"> [perl #71000]
3ab3a109
JV
2218
2219=item *
2220
b6381718
JV
2221Perl now properly returns a syntax error instead of segfaulting
2222if C<each>, C<keys>, or C<values> is used without an argument.
3ab3a109
JV
2223
2224=item *
2225
b6381718
JV
2226C<tell()> now fails properly if called without an argument and when no
2227previous file was read.
3ab3a109 2228
b6381718
JV
2229C<tell()> now returns C<-1>, and sets errno to C<EBADF>, thus restoring
2230the 5.8.x behaviour.
3ab3a109
JV
2231
2232=item *
2233
b6381718
JV
2234C<overload> no longer implicitly unsets fallback on repeated 'use
2235overload' lines.
3ab3a109 2236
72d4e865
JV
2237=item *
2238
b6381718 2239POSIX::strftime() can now handle Unicode characters in the format string.
72d4e865
JV
2240
2241=item *
2242
b6381718
JV
2243The C<syntax> category was removed from 5 warnings that should only be in
2244C<deprecated>.
72d4e865
JV
2245
2246=item *
2247
b6381718
JV
2248Three fatal C<pack>/C<unpack> error messages have been normalized to
2249C<panic: %s>
72d4e865
JV
2250
2251=item *
2252
b6381718
JV
2253C<Unicode character is illegal> has been rephrased to be more accurate
2254
2255It now reads C<Unicode non-character is illegal in interchange> and the
2256perldiag documentation has been expanded a bit.
72d4e865
JV
2257
2258=item *
2259
702b4ef6
JV
2260Currently, all but the first of the several characters that the
2261C<charnames> handler may return are discarded when used in a regular
2262expression pattern bracketed character class. If this happens then the
2263warning C<Using just the first character returned by \N{} in character
2264class> will be issued.
72d4e865
JV
2265
2266=item *
2267
702b4ef6
JV
2268The warning C<Missing right brace on \N{} or unescaped left brace after
2269\N. Assuming the latter> will be issued if Perl encounters a C<\N{>
2270but doesn't find a matching C<}>. In this case Perl doesn't know if it
2271was mistakenly omitted, or if "match non-newline" followed by "match
2272a C<{>" was desired. It assumes the latter because that is actually a
2273valid interpretation as written, unlike the other case. If you meant
2274the former, you need to add the matching right brace. If you did mean
2275the latter, you can silence this warning by writing instead C<\N\{>.
72d4e865
JV
2276
2277=item *
2278
702b4ef6
JV
2279C<gmtime> and C<localtime> called with numbers smaller than they can
2280reliably handle will now issue the warnings C<gmtime(%.0f) too small>
2281and C<localtime(%.0f) too small>.
72d4e865
JV
2282
2283=back
3ab3a109 2284
b6381718 2285The following diagnostic messages have been removed:
c66407fa
RS
2286
2287=over 4
2288
2289=item *
2290
2291C<Runaway format>
2292
2293=item *
2294
2295C<Can't locate package %s for the parents of %s>
2296
b6381718 2297In general this warning it only got produced in
c66407fa
RS
2298conjunction with other warnings, and removing it allowed an ISA lookup
2299optimisation to be added.
2300
2301=item *
2302
2303C<v-string in use/require is non-portable>
2304
2305=back
2306
3ab3a109
JV
2307=head1 Utility Changes
2308
2309=over 4
2310
2311=item *
2312
702b4ef6
JV
2313F<h2ph> now looks in C<include-fixed> too, which is a recent addition
2314to gcc's search path.
3ab3a109
JV
2315
2316=item *
2317
79849ba8 2318F<h2xs> no longer incorrectly treats enum values like macros.
208f012a 2319It also now handles C++ style comments (C<//>) properly in enums.
3ab3a109
JV
2320
2321=item *
2322
d13f8571
JD
2323F<perl5db.pl> now supports C<LVALUE> subroutines. Additionally, the
2324debugger now correctly handles proxy constant subroutines, and
2325subroutine stubs.
3ab3a109
JV
2326
2327=item *
2328
b6381718
JV
2329F<perlbug> now uses C<%Module::CoreList::bug_tracker> to print out
2330upstream bug tracker URLs. If a user identifies a particular module
4655b0a1 2331as the topic of their bug report and we're able to divine the URL for
b6381718
JV
2332its upstream bug tracker, perlbug now provide a message to the user
2333explaining that the core copies the CPAN version directly, and provide
2334the URL for reporting the bug directly to the upstream author.
3ab3a109 2335
702b4ef6
JV
2336F<perlbug> no longer reports "Message sent" when it hasn't actually sent
2337the message
3ab3a109
JV
2338
2339=item *
2340
b6381718
JV
2341F<perlthanks> is a new utility for sending non-bug-reports to the
2342authors and maintainers of Perl. Getting nothing but bug reports can
2343become a bit demoralising. If Perl 5.12 works well for you, please try
2344out F<perlthanks>. It will make the developers smile.
3ab3a109
JV
2345
2346=item *
2347
b6381718 2348Perl's developers have fixed bugs in F<a2p> having to do with the
e014eb68
JV
2349C<match()> operator in list context. Additionally, F<a2p> no longer
2350generates code that uses the C<$[> variable.
3ab3a109
JV
2351
2352=back
2353
2354=head1 Selected Bug Fixes
2355
2356=over 4
2357
2358=item *
2359
b6381718
JV
2360U+0FFFF is now a legal character in regular expressions.
2361
2362=item *
2363
2364pp_qr now always returns a new regexp SV. Resolves RT #69852.
3ab3a109 2365
702b4ef6
JV
2366Instead of returning a(nother) reference to the (pre-compiled) regexp
2367in the optree, use reg_temp_copy() to create a copy of it, and return a
2368reference to that. This resolves issues about Regexp::DESTROY not being
2369called in a timely fashion (the original bug tracked by RT #69852), as
2370well as bugs related to blessing regexps, and of assigning to regexps,
2371as described in correspondence added to the ticket.
3ab3a109
JV
2372
2373It transpires that we also need to undo the SvPVX() sharing when ithreads
702b4ef6
JV
2374cloning a Regexp SV, because mother_re is set to NULL, instead of a
2375cloned copy of the mother_re. This change might fix bugs with regexps
2376and threads in certain other situations, but as yet neither tests nor
2377bug reports have indicated any problems, so it might not actually be an
2378edge case that it's possible to reach.
3ab3a109
JV
2379
2380=item *
2381
702b4ef6
JV
2382Several compilation errors and segfaults when perl was built with C<-Dmad>
2383were fixed.
3ab3a109
JV
2384
2385=item *
2386
2387Fixes for lexer API changes in 5.11.2 which broke NYTProf's savesrc option.
2388
2389=item *
2390
c66407fa 2391C<-t> should only return TRUE for file handles connected to a TTY
3ab3a109 2392
702b4ef6
JV
2393The Microsoft C version of C<isatty()> returns TRUE for all character mode
2394devices, including the F</dev/null>-style "nul" device and printers like
2395"lpt1".
3ab3a109
JV
2396
2397=item *
2398
2399Fixed a regression caused by commit fafafbaf which caused a panic during
2400parameter passing [perl #70171]
2401
2402=item *
2403
2404On systems which in-place edits without backup files, -i'*' now works as
2405the documentation says it does [perl #70802]
2406
2407=item *
2408
2409Saving and restoring magic flags no longer loses readonly flag.
2410
2411=item *
2412
2413The malformed syntax C<grep EXPR LIST> (note the missing comma) no longer
2414causes abrupt and total failure.
2415
2416=item *
2417
2418Regular expressions compiled with C<qr{}> literals properly set C<$'> when
2419matching again.
2420
2421=item *
2422
702b4ef6
JV
2423Using named subroutines with C<sort> should no longer lead to bus errors
2424[perl #71076]
3ab3a109
JV
2425
2426=item *
2427
2428Numerous bugfixes catch small issues caused by the recently-added Lexer API.
2429
2430=item *
2431
2432Smart match against C<@_> sometimes gave false negatives. [perl #71078]
2433
2434=item *
2435
c66407fa
RS
2436C<$@> may now be assigned a read-only value (without error or busting
2437the stack).
3ab3a109
JV
2438
2439=item *
2440
2441C<sort> called recursively from within an active comparison subroutine no
2442longer causes a bus error if run multiple times. [perl #71076]
2443
2444=item *
2445
c66407fa 2446Tie::Hash::NamedCapture::* will not abort if passed bad input (RT #71828)
3ab3a109
JV
2447
2448=item *
2449
2450@_ and $_ no longer leak under threads (RT #34342 and #41138, also
2451#70602, #70974)
2452
2453=item *
2454
2455C<-I> on shebang line now adds directories in front of @INC
2456as documented, and as does C<-I> when specified on the command-line.
2457
2458=item *
2459
2460C<kill> is now fatal when called on non-numeric process identifiers.
c66407fa
RS
2461Previously, an C<undef> process identifier would be interpreted as a
2462request to kill process 0, which would terminate the current process
72d4e865 2463group on POSIX systems. Since process identifiers are always integers,
c66407fa 2464killing a non-numeric process is now fatal.
3ab3a109
JV
2465
2466=item *
2467
24685.10.0 inadvertently disabled an optimisation, which caused a measurable
2469performance drop in list assignment, such as is often used to assign
2470function parameters from C<@_>. The optimisation has been re-instated, and
72d4e865 2471the performance regression fixed. (This fix is also present in 5.10.1)
3ab3a109
JV
2472
2473=item *
2474
2475Fixed memory leak on C<while (1) { map 1, 1 }> [RT #53038].
2476
2477=item *
2478
2479Some potential coredumps in PerlIO fixed [RT #57322,54828].
2480
2481=item *
2482
2483The debugger now works with lvalue subroutines.
2484
2485=item *
2486
2487The debugger's C<m> command was broken on modules that defined constants
2488[RT #61222].
2489
2490=item *
2491
2492C<crypt> and string complement could return tainted values for untainted
2493arguments [RT #59998].
2494
2495=item *
2496
2497The C<-i>I<.suffix> command-line switch now recreates the file using
2498restricted permissions, before changing its mode to match the original
2499file. This eliminates a potential race condition [RT #60904].
2500
2501=item *
2502
2503On some Unix systems, the value in C<$?> would not have the top bit set
2504(C<$? & 128>) even if the child core dumped.
2505
2506=item *
2507
2508Under some circumstances, C<$^R> could incorrectly become undefined
2509[RT #57042].
2510
2511=item *
2512
2513In the XS API, various hash functions, when passed a pre-computed hash where
2514the key is UTF-8, might result in an incorrect lookup.
2515
2516=item *
2517
2518XS code including F<XSUB.h> before F<perl.h> gave a compile-time error
2519[RT #57176].
2520
2521=item *
2522
702b4ef6
JV
2523C<< $object-E<gt>isa('Foo') >> would report false if the package C<Foo>
2524didn't exist, even if the object's C<@ISA> contained C<Foo>.
3ab3a109
JV
2525
2526=item *
2527
2528Various bugs in the new-to 5.10.0 mro code, triggered by manipulating
2529C<@ISA>, have been found and fixed.
2530
2531=item *
2532
2533Bitwise operations on references could crash the interpreter, e.g.
2534C<$x=\$y; $x |= "foo"> [RT #54956].
2535
2536=item *
2537
2538Patterns including alternation might be sensitive to the internal UTF-8
2539representation, e.g.
2540
2541 my $byte = chr(192);
2542 my $utf8 = chr(192); utf8::upgrade($utf8);
2543 $utf8 =~ /$byte|X}/i; # failed in 5.10.0
2544
2545=item *
2546
2547Within UTF8-encoded Perl source files (i.e. where C<use utf8> is in
2548effect), double-quoted literal strings could be corrupted where a C<\xNN>,
2549C<\0NNN> or C<\N{}> is followed by a literal character with ordinal value
2550greater than 255 [RT #59908].
2551
2552=item *
2553
2554C<B::Deparse> failed to correctly deparse various constructs:
2555C<readpipe STRING> [RT #62428], C<CORE::require(STRING)> [RT #62488],
2556C<sub foo(_)> [RT #62484].
2557
2558=item *
2559
2560Using C<setpgrp> with no arguments could corrupt the perl stack.
2561
2562=item *
2563
2564The block form of C<eval> is now specifically trappable by C<Safe> and
72d4e865 2565C<ops>. Previously it was erroneously treated like string C<eval>.
3ab3a109
JV
2566
2567=item *
2568
2569In 5.10.0, the two characters C<[~> were sometimes parsed as the smart
2570match operator (C<~~>) [RT #63854].
2571
2572=item *
2573
2574In 5.10.0, the C<*> quantifier in patterns was sometimes treated as
2575C<{0,32767}> [RT #60034, #60464]. For example, this match would fail:
2576
2577 ("ab" x 32768) =~ /^(ab)*$/
2578
2579=item *
2580
2581C<shmget> was limited to a 32 bit segment size on a 64 bit OS [RT #63924].
2582
2583=item *
2584
2585Using C<next> or C<last> to exit a C<given> block no longer produces a
2586spurious warning like the following:
2587
2588 Exiting given via last at foo.pl line 123
2589
2590=item *
2591
3ab3a109
JV
2592Assigning a format to a glob could corrupt the format; e.g.:
2593
2594 *bar=*foo{FORMAT}; # foo format now bad
2595
2596=item *
2597
2598Attempting to coerce a typeglob to a string or number could cause an
2599assertion failure. The correct error message is now generated,
2600C<Can't coerce GLOB to I<$type>>.
2601
2602=item *
2603
702b4ef6
JV
2604Under C<use filetest 'access'>, C<-x> was using the wrong access
2605mode. This has been fixed [RT #49003].
3ab3a109
JV
2606
2607=item *
2608
2609C<length> on a tied scalar that returned a Unicode value would not be
2610correct the first time. This has been fixed.
2611
2612=item *
2613
2614Using an array C<tie> inside in array C<tie> could SEGV. This has been
2615fixed. [RT #51636]
2616
2617=item *
2618
2619A race condition inside C<PerlIOStdio_close()> has been identified and
2620fixed. This used to cause various threading issues, including SEGVs.
2621
2622=item *
2623
2624In C<unpack>, the use of C<()> groups in scalar context was internally
2625placing a list on the interpreter's stack, which manifested in various
72d4e865 2626ways, including SEGVs. This is now fixed [RT #50256].
3ab3a109
JV
2627
2628=item *
2629
2630Magic was called twice in C<substr>, C<\&$x>, C<tie $x, $m> and C<chop>.
2631These have all been fixed.
2632
2633=item *
2634
2635A 5.10.0 optimisation to clear the temporary stack within the implicit
2636loop of C<s///ge> has been reverted, as it turned out to be the cause of
2637obscure bugs in seemingly unrelated parts of the interpreter [commit
2638ef0d4e17921ee3de].
2639
2640=item *
2641
2642The line numbers for warnings inside C<elsif> are now correct.
2643
2644=item *
2645
2646The C<..> operator now works correctly with ranges whose ends are at or
2647close to the values of the smallest and largest integers.
2648
2649=item *
2650
2651C<binmode STDIN, ':raw'> could lead to segmentation faults on some platforms.
2652This has been fixed [RT #54828].
2653
2654=item *
2655
2656An off-by-one error meant that C<index $str, ...> was effectively being
2657executed as C<index "$str\0", ...>. This has been fixed [RT #53746].
2658
2659=item *
2660
2661Various leaks associated with named captures in regexes have been fixed
2662[RT #57024].
2663
2664=item *
2665
2666A weak reference to a hash would leak. This was affecting C<DBI>
2667[RT #56908].
2668
2669=item *
2670
2671Using (?|) in a regex could cause a segfault [RT #59734].
2672
2673=item *
2674
2675Use of a UTF-8 C<tr//> within a closure could cause a segfault [RT #61520].
2676
2677=item *
2678
2679Calling C<Perl_sv_chop()> or otherwise upgrading an SV could result in an
2680unaligned 64-bit access on the SPARC architecture [RT #60574].
2681
2682=item *
2683
2684In the 5.10.0 release, C<inc_version_list> would incorrectly list
2685C<5.10.*> after C<5.8.*>; this affected the C<@INC> search order
2686[RT #67628].
2687
2688=item *
2689
2690In 5.10.0, C<pack "a*", $tainted_value> returned a non-tainted value
2691[RT #52552].
2692
2693=item *
2694
2695In 5.10.0, C<printf> and C<sprintf> could produce the fatal error
2696C<panic: utf8_mg_pos_cache_update> when printing UTF-8 strings
2697[RT #62666].
2698
2699=item *
2700
2701In the 5.10.0 release, a dynamically created C<AUTOLOAD> method might be
2702missed (method cache issue) [RT #60220,60232].
2703
2704=item *
2705
2706In the 5.10.0 release, a combination of C<use feature> and C<//ee> could
2707cause a memory leak [RT #63110].
2708
2709=item *
2710
2711C<-C> on the shebang (C<#!>) line is once more permitted if it is also
2712specified on the command line. C<-C> on the shebang line used to be a
2713silent no-op I<if> it was not also on the command line, so perl 5.10.0
2714disallowed it, which broke some scripts. Now perl checks whether it is
2715also on the command line and only dies if it is not [RT #67880].
2716
2717=item *
2718
2719In 5.10.0, certain types of re-entrant regular expression could crash,
2720or cause the following assertion failure [RT #60508]:
2721
2722 Assertion rx->sublen >= (s - rx->subbeg) + i failed
2723
2724=item *
2725
702b4ef6
JV
2726Perl now includes previously missing files from the Unicode Character
2727Database.
3ab3a109
JV
2728
2729=item *
2730
b6381718 2731Perl now honors C<TMPDIR> when opening an anonymous temporary file.
3ab3a109
JV
2732
2733=back
2734
b6381718 2735
3ab3a109
JV
2736=head1 Platform Specific Changes
2737
b6381718
JV
2738Perl is incredibly portable. In general, if a platform has a C compiler,
2739someone has ported Perl to it (or will soon). We're happy to announce
2740that Perl 5.12 includes support for several new platforms. At the same
2741time, it's time to bid farewell to some (very) old friends.
2742
3ab3a109
JV
2743=head2 New Platforms
2744
2745=over
2746
2747=item Haiku
2748
702b4ef6
JV
2749Perl's developers have merged patches from Haiku's maintainers. Perl
2750should now build on Haiku.
3ab3a109
JV
2751
2752=item MirOS BSD
2753
2754Perl should now build on MirOS BSD.
2755
3ab3a109
JV
2756=back
2757
2758=head2 Discontinued Platforms
2759
2760=over
2761
3b72faae 2762=item Domain/OS
3ab3a109 2763
3ab3a109
JV
2764=item MiNT
2765
8ead3603
JD
2766=item Tenon MachTen
2767
3ab3a109
JV
2768=back
2769
2770=head2 Updated Platforms
2771
2772=over 4
2773
8ead3603
JD
2774=item AIX
2775
2776=over 4
2777
2778=item *
2779
702b4ef6
JV
2780Removed F<libbsd> for AIX 5L and 6.1. Only C<flock()> was used from
2781F<libbsd>.
8ead3603
JD
2782
2783=item *
2784
702b4ef6
JV
2785Removed F<libgdbm> for AIX 5L and 6.1 if F<libgdbm> < 1.8.3-5 is
2786installed. The F<libgdbm> is delivered as an optional package with the
2787AIX Toolbox. Unfortunately the versions below 1.8.3-5 are broken.
8ead3603
JD
2788
2789=item *
2790
2791Hints changes mean that AIX 4.2 should work again.
2792
2793=back
2794
2795=item Cygwin
2796
2797=over 4
2798
2799=item *
2800
2801Perl now supports IPv6 on Cygwin 1.7 and newer.
2802
2803=item *
2804
2805On Cygwin we now strip the last number from the DLL. This has been the
2806behaviour in the cygwin.com build for years. The hints files have been
2807updated.
2808
2809=back
2810
3ab3a109
JV
2811=item Darwin (Mac OS X)
2812
2813=over 4
2814
2815=item *
2816
2817Skip testing the be_BY.CP1131 locale on Darwin 10 (Mac OS X 10.6),
2818as it's still buggy.
2819
2820=item *
2821
2822Correct infelicities in the regexp used to identify buggy locales
2823on Darwin 8 and 9 (Mac OS X 10.4 and 10.5, respectively).
2824
2825=back
2826
2827=item DragonFly BSD
2828
2829=over 4
2830
2831=item *
2832
2833Fix thread library selection [perl #69686]
2834
2835=back
2836
8ead3603 2837=item FreeBSD
3ab3a109
JV
2838
2839=over 4
2840
2841=item *
2842
8ead3603
JD
2843The hints files now identify the correct threading libraries on FreeBSD 7
2844and later.
3ab3a109 2845
8ead3603 2846=back
3ab3a109 2847
8ead3603 2848=item Irix
3ab3a109 2849
8ead3603 2850=over 4
3ab3a109
JV
2851
2852=item *
2853
8ead3603
JD
2854We now work around a bizarre preprocessor bug in the Irix 6.5 compiler:
2855C<cc -E -> unfortunately goes into K&R mode, but C<cc -E file.c> doesn't.
3ab3a109
JV
2856
2857=back
2858
8ead3603 2859=item NetBSD
3ab3a109
JV
2860
2861=over 4
2862
2863=item *
2864
8ead3603 2865Hints now supports versions 5.*.
3ab3a109
JV
2866
2867=back
2868
2869=item OpenVMS
2870
2871=over 4
2872
2873=item *
2874
b6381718 2875C<-UDEBUGGING> is now the default on VMS.
3ab3a109 2876
702b4ef6
JV
2877Like it has been everywhere else for ages and ages. Also make command-line
2878selection of -UDEBUGGING and -DDEBUGGING work in configure.com; before
2879the only way to turn it off was by saying no in answer to the interactive
2880question.
3ab3a109
JV
2881
2882=item *
2883
2884The default pipe buffer size on VMS has been updated to 8192 on 64-bit
2885systems.
2886
2887=item *
2888
2889Reads from the in-memory temporary files of C<PerlIO::scalar> used to fail
2890if C<$/> was set to a numeric reference (to indicate record-style reads).
2891This is now fixed.
2892
2893=item *
2894
2895VMS now supports C<getgrgid>.
2896
2897=item *
2898
2899Many improvements and cleanups have been made to the VMS file name handling
2900and conversion code.
2901
2902=item *
2903
2904Enabling the C<PERL_VMS_POSIX_EXIT> logical name now encodes a POSIX exit
2905status in a VMS condition value for better interaction with GNV's bash
72d4e865 2906shell and other utilities that depend on POSIX exit values. See
3ab3a109
JV
2907L<perlvms/"$?"> for details.
2908
2909=item *
2910
2911C<File::Copy> now detects Unix compatibility mode on VMS.
2912
2913=back
2914
8ead3603 2915=item Stratus VOS
3ab3a109 2916
8ead3603 2917=over 4
3ab3a109 2918
8ead3603 2919=item *
3ab3a109 2920
8ead3603 2921Various changes from Stratus have been merged in.
3ab3a109 2922
8ead3603 2923=back
3ab3a109 2924
8ead3603 2925=item Symbian
3ab3a109 2926
8ead3603 2927=over 4
3ab3a109 2928
8ead3603 2929=item *
3ab3a109 2930
8ead3603 2931There is now support for Symbian S60 3.2 SDK and S60 5.0 SDK.
3ab3a109 2932
8ead3603 2933=back
3ab3a109 2934
d13f8571 2935=item Windows
3ab3a109 2936
8ead3603 2937=over 4
3ab3a109 2938
8ead3603 2939=item *
3ab3a109 2940
d13f8571
JD
2941Perl 5.12 supports Windows 2000 and later. The supporting code for
2942legacy versions of Windows is still included, but will be removed
2943during the next development cycle.
3ab3a109 2944
8ead3603 2945=item *
3ab3a109 2946
d13f8571 2947Initial support for building Perl with MinGW-w64 is now available.
3ab3a109 2948
8ead3603
JD
2949=item *
2950
d13f8571 2951F<perl.exe> now includes a manifest resource to specify the C<trustInfo>
8ead3603 2952settings for Windows Vista and later. Without this setting Windows
d13f8571 2953would treat F<perl.exe> as a legacy application and apply various
8ead3603
JD
2954heuristics like redirecting access to protected file system areas
2955(like the "Program Files" folder) to the users "VirtualStore"
2956instead of generating a proper "permission denied" error.
2957
d13f8571
JD
2958The manifest resource also requests the Microsoft Common-Controls
2959version 6.0 (themed controls introduced in Windows XP). Check out the
2960Win32::VisualStyles module on CPAN to switch back to old style
2961unthemed controls for legacy applications.
2962
2963=item *
2964
2965The C<-t> filetest operator now only returns true if the filehandle
2966is connected to a console window. In previous versions of Perl it
2967would return true for all character mode devices, including F<NUL>
2968and F<LPT1>.
2969
2970=item *
2971
2972The C<-p> filetest operator now works correctly, and the
2973Fcntl::S_IFIFO constant is defined when Perl is compiled with
2974Microsoft Visual C. In previous Perl versions C<-p> always
2975returned a false value, and the Fcntl::S_IFIFO constant
2976was not defined.
2977
2978This bug is specific to Microsoft Visual C and never affected
2979Perl binaries built with MinGW.
2980
2981=item *
2982
2983The socket error codes are now more widely supported: The POSIX
2984module will define the symbolic names, like POSIX::EWOULDBLOCK,
2985and stringification of socket error codes in $! works as well
2986now;
2987
2988 C:\>perl -MPOSIX -E "$!=POSIX::EWOULDBLOCK; say $!"
2989 A non-blocking socket operation could not be completed immediately.
2990
2991=item *
2992
2993flock() will now set sensible error codes in $!. Previous Perl versions
2994copied the value of $^E into $!, which caused much confusion.
2995
2996=item *
2997
2998select() now supports all empty C<fd_set>s more correctly.
8ead3603 2999
d13f8571
JD
3000=item *
3001
3002C<'.\foo'> and C<'..\foo'> were treated differently than
3003C<'./foo'> and C<'../foo'> by C<do> and C<require> [RT #63492].
8ead3603
JD
3004
3005=item *
3006
3007Improved message window handling means that C<alarm> and C<kill> messages
3008will no longer be dropped under race conditions.
3009
d13f8571
JD
3010=item *
3011
3012Various bits of Perl's build infrastructure are no longer converted to
3013win32 line endings at release time. If this hurts you, please report the
3014problem with the L<perlbug> program included with perl.
3015
8ead3603 3016=back
3ab3a109
JV
3017
3018=back
3019
b6381718 3020
3ab3a109
JV
3021=head1 Known Problems
3022
3023This is a list of some significant unfixed bugs, which are regressions
72d4e865 3024from either 5.10.x or 5.8.x.
3ab3a109
JV
3025
3026=over 4
3027
3028=item *
3029
3030C<List::Util::first> misbehaves in the presence of a lexical C<$_>
3031(typically introduced by C<my $_> or implicitly by C<given>). The variable
3032which gets set for each iteration is the package variable C<$_>, not the
3033lexical C<$_> [RT #67694].
3034
3035A similar issue may occur in other modules that provide functions which
3036take a block as their first argument, like
3037
3038 foo { ... $_ ...} list
3039
3040=item *
3041
3ab3a109
JV
3042Some regexes may run much more slowly when run in a child thread compared
3043with the thread the pattern was compiled into [RT #55600].
3044
3045=item *
3046
3d3a8206
KW
3047Things like C<"\N{LATIN SMALL LIGATURE FF}" =~ /\N{LATIN SMALL LETTER F}+/>
3048will appear to hang as they get into a very long running loop [RT #72998].
3049
3050=item *
3051
d13f8571
JD
3052Several porters have reported mysterious crashes when Perl's entire
3053test suite is run after a build on certain Windows 2000 systems. When
3054run by hand, the individual tests reportedly work fine.
3ab3a109 3055
b6381718
JV
3056=back
3057
3058=head1 Errata
3059
3060=over
3061
3ab3a109
JV
3062=item *
3063
b6381718
JV
3064This one is actually a change introduced in 5.10.0, but it was missed
3065from that release's perldelta, so it is mentioned here instead.
3066
3067A bugfix related to the handling of the C</m> modifier and C<qr> resulted
3068in a change of behaviour between 5.8.x and 5.10.0:
3ab3a109 3069
b6381718
JV
3070 # matches in 5.8.x, doesn't match in 5.10.0
3071 $re = qr/^bar/; "foo\nbar" =~ /$re/m;
3ab3a109 3072
3ab3a109
JV
3073=back
3074
3075=head1 Acknowledgements
3076
3077Perl 5.12.0 represents approximately two years of development since
aac88411 3078Perl 5.10.0 and contains over 750,000 lines of changes across over
ee75e258 30793,000 files from over 200 authors and committers.
aac88411 3080
d13f8571
JD
3081Perl continues to flourish into its third decade thanks to a vibrant
3082community of users and developers. The following people are known to
3083have contributed the improvements that became Perl 5.12.0:
aac88411
JV
3084
3085Aaron Crane, Abe Timmerman, Abhijit Menon-Sen, Abigail, Adam Russell,
3086Adriano Ferreira, Ævar Arnfjörð Bjarmason, Alan Grover, Alexandr
3087Ciornii, Alex Davies, Alex Vandiver, Andreas Koenig, Andrew Rodland,
3088andrew@sundale.net, Andy Armstrong, Andy Dougherty, Jose AUGUSTE-ETIENNE,
3089Benjamin Smith, Ben Morrow, bharanee rathna, Bo Borgerson, Bo Lindbergh,
3090Brad Gilbert, Bram, Brendan O'Dea, brian d foy, Charles Bailey,
3091Chip Salzenberg, Chris 'BinGOs' Williams, Christoph Lamprecht, Chris
3092Williams, chromatic, Claes Jakobsson, Craig A. Berry, Dan Dascalescu,
3093Daniel Frederick Crisman, Daniel M. Quinlan, Dan Jacobson, Dan Kogai,
3094Dave Mitchell, Dave Rolsky, David Cantrell, David Dick, David Golden,
3095David Mitchell, David M. Syzdek, David Nicol, David Wheeler, Dennis
3096Kaarsemaker, Dintelmann, Peter, Dominic Dunlop, Dr.Ruud, Duke Leto,
3097Enrico Sorcinelli, Eric Brine, Father Chrysostomos, Florian Ragwitz,
3098Frank Wiegand, Gabor Szabo, Gene Sullivan, Geoffrey T. Dairiki, George
3099Greer, Gerard Goossen, Gisle Aas, Goro Fuji, Graham Barr, Green, Paul,
3100Hans Dieter Pearcey, Harmen, H. Merijn Brand, Hugo van der Sanden,
3101Ian Goodacre, Igor Sutton, Ingo Weinhold, James Bence, James Mastros,
3102Jan Dubois, Jari Aalto, Jarkko Hietaniemi, Jay Hannah, Jerry Hedden,
3103Jesse Vincent, Jim Cromie, Jody Belka, John E. Malmberg, John Malmberg,
3104John Peacock, John Peacock via RT, John P. Linderman, John Wright,
3105Josh ben Jore, Jos I. Boumans, Karl Williamson, Kenichi Ishigaki, Ken
3106Williams, Kevin Brintnall, Kevin Ryde, Kurt Starsinic, Leon Brocard,
3107Lubomir Rintel, Luke Ross, Marcel Grünauer, Marcus Holland-Moritz, Mark
3108Jason Dominus, Marko Asplund, Martin Hasch, Mashrab Kuvatov, Matt Kraai,
3109Matt S Trout, Max Maischein, Michael Breen, Michael Cartmell, Michael
3110G Schwern, Michael Witten, Mike Giroux, Milosz Tanski, Moritz Lenz,
3111Nicholas Clark, Nick Cleaton, Niko Tyni, Offer Kaye, Osvaldo Villalon,
3112Paul Fenwick, Paul Gaborit, Paul Green, Paul Johnson, Paul Marquess,
3113Philip Hazel, Philippe Bruhat, Rafael Garcia-Suarez, Rainer Tammer,
3114Rajesh Mandalemula, Reini Urban, Renée Bäcker, Ricardo Signes,
3115Ricardo SIGNES, Richard Foley, Rich Rauenzahn, Rick Delaney, Risto
3116Kankkunen, Robert May, Roberto C. Sanchez, Robin Barker, SADAHIRO
3117Tomoyuki, Salvador Ortiz Garcia, Sam Vilain, Scott Lanning, Sébastien
3118Aperghis-Tramoni, Sérgio Durigan Júnior, Shlomi Fish, Simon 'corecode'
3119Schubert, Sisyphus, Slaven Rezic, Smylers, Steffen Müller, Steffen
3120Ullrich, Stepan Kasal, Steve Hay, Steven Schubiger, Steve Peters, Tels,
3121The Doctor, Tim Bunce, Tim Jenness, Todd Rinaldo, Tom Christiansen,
3122Tom Hukins, Tom Wyant, Tony Cook, Torsten Schoenfeld, Tye McQueen,
3123Vadim Konovalov, Vincent Pit, Hio YAMASHINA, Yasuhiro Matsumoto,
3124Yitzchak Scott-Thoennes, Yuval Kogman, Yves Orton, Zefram, Zsban Ambrus
3125
3126This is woefully incomplete as it's automatically generated from version
3127control history. In particular, it doesn't include the names of the
3128(very much appreciated) contributors who reported issues in previous
3129versions of Perl that helped make Perl 5.12.0 better. For a more complete
3130list of all of Perl's historical contributors, please see the C<AUTHORS>
3131file in the Perl 5.12.0 distribution.
3ab3a109 3132
c8937c7e
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3133Our "retired" pumpkings Nicholas Clark and Rafael Garcia-Suarez
3134deserve special thanks for their brilliant and substantive ongoing
3135contributions. Nicholas personally authored over 30% of the patches
3136since 5.10.0. Rafael comes in second in patch authorship with 11%,
3137but is first by a long shot in committing patches authored by others,
3138pushing 44% of the commits since 5.10.0 in this category, often after
3139providing considerable coaching to the patch authors. These statistics
3140in no way comprise all of their contributions, but express in shorthand
3141that we couldn't have done it without them.
3142
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3143Many of the changes included in this version originated in the CPAN
3144modules included in Perl's core. We're grateful to the entire CPAN
3145community for helping Perl to flourish.
3146
3147=head1 Reporting Bugs
3148
3149If you find what you think is a bug, you might check the articles
3150recently posted to the comp.lang.perl.misc newsgroup and the perl
72d4e865 3151bug database at L<http://rt.perl.org/perlbug/>. There may also be
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3152information at L<http://www.perl.org/>, the Perl Home Page.
3153
3154If you believe you have an unreported bug, please run the B<perlbug>
72d4e865
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3155program included with your release. Be sure to trim your bug down
3156to a tiny but sufficient test case. Your bug report, along with the
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3157output of C<perl -V>, will be sent off to perlbug@perl.org to be
3158analyzed by the Perl porting team.
3159
3160If the bug you are reporting has security implications, which make it
3161inappropriate to send to a publicly archived mailing list, then please send
3162it to perl5-security-report@perl.org. This points to a closed subscription
3163unarchived mailing list, which includes all the core committers, who be able
3164to help assess the impact of issues, figure out a resolution, and help
3165co-ordinate the release of patches to mitigate or fix the problem across all
3166platforms on which Perl is supported. Please only use this address for
3167security issues in the Perl core, not for modules independently
3168distributed on CPAN.
3169
3170=head1 SEE ALSO
3171
3172The F<Changes> file for an explanation of how to view exhaustive details
3173on what changed.
3174
3175The F<INSTALL> file for how to build Perl.
3176
3177The F<README> file for general stuff.
3178
3179The F<Artistic> and F<Copying> files for copyright information.
3180
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3181L<http://dev.perl.org/perl5/errata.html> for a list of issues
3182found after this release, as well as a list of CPAN modules known
3183to be incompatible with this release.
3184
3ab3a109 3185=cut