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1=encoding utf8
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3=head1 NAME
4
5perl5120delta - what is new for perl v5.12.0
6
7=head1 DESCRIPTION
8
9This document describes differences between the 5.10.0 release and
10the 5.12.0 release.
11
72d4e865 12Many of the bug fixes in 5.12.0 are already included in the 5.10.1
b16f1257 13maintenance release.
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14
15You can see the list of those changes in the 5.10.1 release notes (L<perl5101delta>).
16
17
b6381718 18=head1 Core Enhancements
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19
20=head2 New C<package NAME VERSION> syntax
21
22This new syntax allows a module author to set the $VERSION of a namespace
23when the namespace is declared with 'package'. It eliminates the need
24for C<our $VERSION = ...> and similar constructs. E.g.
25
26 package Foo::Bar 1.23;
27 # $Foo::Bar::VERSION == 1.23
28
29There are several advantages to this:
30
b16f1257 31=over
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32
33=item *
34
35C<$VERSION> is parsed in exactly the same way as C<use NAME VERSION>
36
37=item *
38
39C<$VERSION> is set at compile time
40
41=item *
42
43C<$VERSION> is a version object that provides proper overloading of
4655b0a1 44comparison operators so comparing C<$VERSION> to decimal (1.23) or
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45dotted-decimal (v1.2.3) version numbers works correctly.
46
47=item *
48
49Eliminates C<$VERSION = ...> and C<eval $VERSION> clutter
50
51=item *
52
53As it requires VERSION to be a numeric literal or v-string
54literal, it can be statically parsed by toolchain modules
55without C<eval> the way MM-E<gt>parse_version does for C<$VERSION = ...>
56
e014eb68 57=back
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58
59It does not break old code with only C<package NAME>, but code that uses
60C<package NAME VERSION> will need to be restricted to perl 5.12.0 or newer
61This is analogous to the change to C<open> from two-args to three-args.
62Users requiring the latest Perl will benefit, and perhaps after several
63years, it will become a standard practice.
64
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65
66However, C<package NAME VERSION> requires a new, 'strict' version
67number format. See L<"Version number formats"> for details.
68
69
70=head2 The C<...> operator
71
72A new operator, C<...>, nicknamed the Yada Yada operator, has been added.
73It is intended to mark placeholder code that is not yet implemented.
79849ba8 74See L<perlop/"Yada Yada Operator">.
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75
76=head2 Implicit strictures
77
78Using the C<use VERSION> syntax with a version number greater or equal
79to 5.11.0 will lexically enable strictures just like C<use strict>
80would do (in addition to enabling features.) The following:
81
82 use 5.12.0;
83
84means:
85
86 use strict;
87 use feature ':5.12';
01358b4a 88
b6381718 89=head2 Unicode improvements
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91Perl 5.12 comes with Unicode 5.2, the latest version available to
92us at the time of release. This version of Unicode was released in
93October 2009. See L<http://www.unicode.org/versions/Unicode5.2.0> for
94further details about what's changed in this version of the standard.
95See L<perlunicode> for instructions on installing and using other versions
96of Unicode.
97
98Additionally, Perl's developers have significantly improved Perl's Unicode
99implementation. For full details, see L</Unicode overhaul> below.
100
101=head2 Y2038 compliance
102
103Perl'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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104
105=head2 qr overloading
106
107It is now possible to overload the C<qr//> operator, that is,
108conversion to regexp, like it was already possible to overload
109conversion to boolean, string or number of objects. It is invoked when
c66407fa 110an object appears on the right hand side of the C<=~> operator or when
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111it is interpolated into a regexp. See L<overload>.
112
113=head2 Pluggable keywords
114
115Extension modules can now cleanly hook into the Perl parser to define
116new kinds of keyword-headed expression and compound statement. The
117syntax following the keyword is defined entirely by the extension. This
118allow a completely non-Perl sublanguage to be parsed inline, with the
b16f1257 119correct ops cleanly generated.
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120
121See L<perlapi/PL_keyword_plugin> for the mechanism. The Perl core
122source distribution also includes a new module
123L<XS::APItest::KeywordRPN>, which implements reverse Polish notation
124arithmetic via pluggable keywords. This module is mainly used for test
125purposes, and is not normally installed, but also serves as an example
126of how to use the new mechanism.
127
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128Perl's developers consider this feature to be experimental. We may remove
129it or change it in a backwards-incompatible way in Perl 5.14.
130
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131=head2 APIs for more internals
132
133The lowest layers of the lexer and parts of the pad system now have C
134APIs available to XS extensions. These are necessary to support proper
135use of pluggable keywords, but have other uses too. The new APIs are
136experimental, and only cover a small proportion of what would be
137necessary to take full advantage of the core's facilities in these
138areas. It is intended that the Perl 5.13 development cycle will see the
139addition of a full range of clean, supported interfaces.
140
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141Perl's developers consider this feature to be experimental. We may remove
142it or change it in a backwards-incompatible way in Perl 5.14.
143
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144=head2 Overridable function lookup
145
146Where an extension module hooks the creation of rv2cv ops to modify the
147subroutine lookup process, this now works correctly for bareword
148subroutine calls. This means that prototypes on subroutines referenced
149this way will be processed correctly. (Previously bareword subroutine
150names were initially looked up, for parsing purposes, by an unhookable
151mechanism, so extensions could only properly influence subroutine names
152that appeared with an C<&> sigil.)
153
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154=head2 A proper interface for pluggable Method Resolution Orders
155
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156As of Perl 5.12.0 there is a new interface for plugging and using method
157resolution orders other than the default linear depth first search.
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158The C3 method resolution order added in 5.10.0 has been re-implemented as
159a plugin, without changing its Perl-space interface. See L<perlmroapi> for
160more information.
161
b3b85878 162
5e75e599 163
72d4e865 164=head2 C<\N> experimental regex escape
3ab3a109 165
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166Perl now supports C<\N>, a new regex escape which you can think of as
167the inverse of C<\n>. It will match any character that is not a newline,
168independently from the presence or absence of the single line match
169modifier C</s>. It is not usable within a character class. C<\N{3}>
170means to match 3 non-newlines; C<\N{5,}> means to match at least 5.
171C<\N{NAME}> still means the character or sequence named C<NAME>, but
172C<NAME> no longer can be things like C<3>, or C<5,>.
173
174This will break a L<custom charnames translator|charnames/CUSTOM
175TRANSLATORS> which allows numbers for character names, as C<\N{3}> will
176now mean to match 3 non-newline characters, and not the character whose
177name is C<3>. (No name defined by the Unicode standard is a number,
178so only custom translators might be affected.)
179
180Perl's developers are somewhat concerned about possible user confusion
181with the existing C<\N{...}> construct which matches characters by their
182Unicode name. Consequently, this feature is experimental. We may remove
183it or change it in a backwards-incompatible way in Perl 5.14.
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184
185=head2 DTrace support
186
72d4e865 187Perl now has some support for DTrace. See "DTrace support" in F<INSTALL>.
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188
189=head2 Support for C<configure_requires> in CPAN module metadata
190
191Both C<CPAN> and C<CPANPLUS> now support the C<configure_requires> keyword
192in the F<META.yml> metadata file included in most recent CPAN distributions.
193This allows distribution authors to specify configuration prerequisites that
194must be installed before running F<Makefile.PL> or F<Build.PL>.
195
196See the documentation for C<ExtUtils::MakeMaker> or C<Module::Build> for more
197on how to specify C<configure_requires> when creating a distribution for CPAN.
198
199=head2 C<each> is now more flexible
200
201The C<each> function can now operate on arrays.
202
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203=head2 C<when> as a statement modifier
204
205C<when> is now allowed to be used as a statement modifier.
206
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207=head2 C<$,> flexibility
208
209The variable C<$,> may now be tied.
210
61f382b0 211=head2 // in when clauses
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212
213// now behaves like || in when clauses
214
215=head2 Enabling warnings from your shell environment
216
217You can now set C<-W> from the C<PERL5OPT> environment variable
218
219=head2 C<delete local>
220
221C<delete local> now allows you to locally delete a hash entry.
222
223=head2 New support for Abstract namespace sockets
224
225Abstract namespace sockets are Linux-specific socket type that live in
226AF_UNIX family, slightly abusing it to be able to use arbitrary
227character arrays as addresses: They start with nul byte and are not
228terminated by nul byte, but with the length passed to the socket()
229system call.
230
72d4e865 231=head2 32-bit limit on substr arguments removed
3ab3a109 232
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233The 32-bit limit on C<substr> arguments has now been removed. The full range
234of the system's signed and unsigned integers is now available for the C<pos>
235and C<len> arguments.
3ab3a109 236
b6381718 237=head1 Potentially Incompatible Changes
3ab3a109 238
72d4e865 239=head2 Deprecations warn by default
3ab3a109 240
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241Perl now defaults to issuing a warning if a deprecated language feature
242is used.
252eec4f 243
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244To disable this feature in a given lexical scope, you should use C<no
245warnings 'deprecated';> For information about which language features
246are deprecated and explanations of various deprecation warnings, please
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247see L<perldiag.pod>. See L</Deprecations> below for the list of features
248and modules Perl's developers have deprecated as part of this release.
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249
250=head2 Version number formats
251
252Acceptable version number formats have been formalized into "strict" and
72d4e865 253"lax" rules. C<package NAME VERSION> takes a strict version number.
fab55263 254C<UNIVERSAL::VERSION> and the L<version> object constructors take lax
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255version numbers. Providing an invalid version will result in a fatal
256error. The version argument in C<use NAME VERSION> is first parsed as a
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257numeric literal or v-string and then passed to C<UNIVERSAL::VERSION>
258(and must then pass the "lax" format test).
259
72d4e865 260These formats are documented fully in the L<version> module. To a first
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261approximation, a "strict" version number is a positive decimal number
262(integer or decimal-fraction) without exponentiation or else a
263dotted-decimal v-string with a leading 'v' character and at least three
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264components. A "lax" version number allows v-strings with fewer than
265three components or without a leading 'v'. Under "lax" rules, both
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266decimal and dotted-decimal versions may have a trailing "alpha"
267component separated by an underscore character after a fractional or
268dotted-decimal component.
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269
270The L<version> module adds C<version::is_strict> and C<version::is_lax>
271functions to check a scalar against these rules.
272
c66407fa 273=head2 @INC reorganization
3ab3a109 274
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275In C<@INC>, C<ARCHLIB> and C<PRIVLIB> now occur after after the current
276version's C<site_perl> and C<vendor_perl>. Modules installed into
277C<site_perl> and C<vendor_perl> will now be loaded in preference to
278those installed in C<ARCHLIB> and C<PRIVLIB>.
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279
280=head2 Switch statement changes
281
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282The C<given>/C<when> switch statement handles complex statements better
283than Perl 5.10.0 did (These enhancements are also available in
2845.10.1 and subsequent 5.10 releases.) There are two new cases where
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285C<when> now interprets its argument as a boolean, instead of an
286expression to be used in a smart match:
3ab3a109 287
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288=over
289
290=item flip-flop operators
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291
292The C<..> and C<...> flip-flop operators are now evaluated in boolean
293context, following their usual semantics; see L<perlop/"Range Operators">.
294
295Note that, as in perl 5.10.0, C<when (1..10)> will not work to test
296whether a given value is an integer between 1 and 10; you should use
297C<when ([1..10])> instead (note the array reference).
298
299However, contrary to 5.10.0, evaluating the flip-flop operators in boolean
300context ensures it can now be useful in a C<when()>, notably for
301implementing bistable conditions, like in:
302
303 when (/^=begin/ .. /^=end/) {
304 # do something
305 }
306
b6381718 307=item defined-or operator
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308
309A compound expression involving the defined-or operator, as in
310C<when (expr1 // expr2)>, will be treated as boolean if the first
311expression is boolean. (This just extends the existing rule that applies
312to the regular or operator, as in C<when (expr1 || expr2)>.)
313
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314=back
315
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316=head2 Smart match changes
317
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318Since Perl 5.10.0, Perl's developers have made a number of changes to
319the smart match operator. These, of course, also alter the behaviour
3ab3a109 320of the switch statements where smart matching is implicitly used.
c66407fa 321These changes were also made for the 5.10.1 release, and will remain in
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322subsequent 5.10 releases.
323
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324=head3 Changes to type-based dispatch
325
326The smart match operator C<~~> is no longer commutative. The behaviour of
327a smart match now depends primarily on the type of its right hand
328argument. Moreover, its semantics have been adjusted for greater
329consistency or usefulness in several cases. While the general backwards
330compatibility is maintained, several changes must be noted:
331
332=over 4
333
334=item *
335
336Code references with an empty prototype are no longer treated specially.
337They are passed an argument like the other code references (even if they
338choose to ignore it).
339
340=item *
341
342C<%hash ~~ sub {}> and C<@array ~~ sub {}> now test that the subroutine
343returns a true value for each key of the hash (or element of the
344array), instead of passing the whole hash or array as a reference to
345the subroutine.
346
347=item *
348
349Due to the commutativity breakage, code references are no longer
350treated specially when appearing on the left of the C<~~> operator,
351but like any vulgar scalar.
352
353=item *
354
355C<undef ~~ %hash> is always false (since C<undef> can't be a key in a
356hash). No implicit conversion to C<""> is done (as was the case in perl
3575.10.0).
358
359=item *
360
361C<$scalar ~~ @array> now always distributes the smart match across the
362elements of the array. It's true if one element in @array verifies
363C<$scalar ~~ $element>. This is a generalization of the old behaviour
364that tested whether the array contained the scalar.
365
366=back
367
368The full dispatch table for the smart match operator is given in
369L<perlsyn/"Smart matching in detail">.
370
371=head3 Smart match and overloading
372
373According to the rule of dispatch based on the rightmost argument type,
374when an object overloading C<~~> appears on the right side of the
375operator, the overload routine will always be called (with a 3rd argument
376set to a true value, see L<overload>.) However, when the object will
377appear on the left, the overload routine will be called only when the
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378rightmost argument is a simple scalar. This way, distributivity of smart
379match across arrays is not broken, as well as the other behaviours with
380complex types (coderefs, hashes, regexes). Thus, writers of overloading
381routines for smart match mostly need to worry only with comparing
382against a scalar, and possibly with stringification overloading; the
383other common cases will be automatically handled consistently.
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384
385C<~~> will now refuse to work on objects that do not overload it (in order
386to avoid relying on the object's underlying structure). (However, if the
387object overloads the stringification or the numification operators, and
388if overload fallback is active, it will be used instead, as usual.)
389
b6381718 390=head2 Other potentially incompatible changes
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391
392=over 4
393
394=item *
395
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396The definitions of a number of Unicode properties have changed to match
397those of the current Unicode standard. These are listed above under
b6381718 398L</Unicode overhaul>. This change may break code that expects the old definitions.
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399
400=item *
401
b6381718 402The boolkeys op has moved to the group of hash ops. This breaks binary
b21d8e53 403compatibility.
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404
405=item *
406
72d4e865 407Filehandles are now always blessed into C<IO::File>.
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408
409The previous behaviour was to bless Filehandles into L<FileHandle>
410(an empty proxy class) if it was loaded into memory and otherwise
411to bless them into C<IO::Handle>.
412
413=item *
414
415The semantics of C<use feature :5.10*> have changed slightly.
416See L<"Modules and Pragmata"> for more information.
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417
418=item *
419
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420Perl's developers now use git, rather than Perforce. This should be
421a purely internal change only relevant to people actively working on
422the core. However, you may see minor difference in perl as a consequence
423of the change. For example in some of details of the output of C<perl
424-V>. See L<perlrepository> for more information.
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425
426=item *
427
428As part of the C<Test::Harness> 2.x to 3.x upgrade, the experimental
429C<Test::Harness::Straps> module has been removed.
b6381718 430See L</"Modules and Pragmata"> for more details.
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431
432=item *
433
434As part of the C<ExtUtils::MakeMaker> upgrade, the
435C<ExtUtils::MakeMaker::bytes> and C<ExtUtils::MakeMaker::vmsish> modules
436have been removed from this distribution.
437
438=item *
439
440C<Module::CoreList> no longer contains the C<%:patchlevel> hash.
441
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442
443=item *
444
445C<length undef> now returns undef.
446
447=item *
448
449Unsupported private C API functions are now declared "static" to prevent
450leakage to Perl's public API.
451
452=item *
453
454To support the bootstrapping process, F<miniperl> no longer builds with
455UTF-8 support in the regexp engine.
456
457This allows a build to complete with PERL_UNICODE set and a UTF-8 locale.
458Without this there's a bootstrapping problem, as miniperl can't load the UTF-8
459components of the regexp engine, because they're not yet built.
460
461=item *
462
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463F<miniperl>'s @INC is now restricted to just C<-I...>, the split of
464C<$ENV{PERL5LIB}>, and "C<.>"
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465
466=item *
467
468A space or a newline is now required after a C<"#line XXX"> directive.
469
470=item *
471
472Tied filehandles now have an additional method EOF which provides the EOF type
473
474=item *
475
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476To better match all other flow control statements, C<foreach> may no
477longer be used as an attribute.
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478
479=back
480
b6381718 481
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482=head1 Deprecations
483
484From time to time, Perl's developers find it necessary to deprecate
485features or modules we've previously shipped as part of the core
486distribution. We are well aware of the pain and frustration that a
487backwards-incompatible change to Perl can cause for developers building
488or maintaining software in Perl. You can be sure that when we deprecate
489a functionality or syntax, it isn't a choice we make lightly. Sometimes,
490we choose to deprecate functionality or syntax because it was found to
491be poorly designed or implemented. Sometimes, this is because they're
492holding back other features or causing performance problems. Sometimes,
493the reasons are more complex. Wherever possible, we try to keep deprecated
494functionality available to developers in its previous form for at least
72d4e865 495one major release. So long as a deprecated feature isn't actively
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496disrupting our ability to maintain and extend Perl, we'll try to leave
497it in place as long as possible.
498
b6381718 499The following items are now deprecated:
3ab3a109 500
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501=over
502
503=item suidperl
504
505C<suidperl> is no longer part of Perl. It used to provide a mechanism to
506emulate setuid permission bits on systems that don't support it properly.
3ab3a109 507
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508
509=item Use of C<:=> to mean an empty attribute list
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510
511An accident of Perl's parser meant that these constructions were all
512equivalent:
513
514 my $pi := 4;
515 my $pi : = 4;
516 my $pi : = 4;
517
518with the C<:> being treated as the start of an attribute list, which
519ends before the C<=>. As whitespace is not significant here, all are
520parsed as an empty attribute list, hence all the above are equivalent
521to, and better written as
522
523 my $pi = 4;
524
525because no attribute processing is done for an empty list.
526
527As is, this meant that C<:=> cannot be used as a new token, without
528silently changing the meaning of existing code. Hence that particular
529form is now deprecated, and will become a syntax error. If it is
530absolutely necessary to have empty attribute lists (for example,
531because of a code generator) then avoid the warning by adding a space
532before the C<=>.
533
c66407fa 534=item C<< UNIVERSAL->import() >>
3ab3a109 535
72d4e865 536The method C<< UNIVERSAL->import() >> is now deprecated. Attempting to
3ab3a109 537pass import arguments to a C<use UNIVERSAL> statement will result in a
c66407fa 538deprecation warning.
3ab3a109 539
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540
541=item Use of "goto" to jump into a construct
3ab3a109 542
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543Using C<goto> to jump from an outer scope into an inner scope is now
544deprecated. This rare use case was causing problems in the
545implementation of scopes.
3ab3a109 546
b6381718 547=item Custom character names in \N{name} that don't look like names
8c66a230 548
72d4e865 549In C<\N{I<name>}>, I<name> can be just about anything. The standard Unicode
8c66a230 550names have a very limited domain, but a custom name translator could create
72d4e865 551names that are, for example, made up entirely of punctuation symbols. It is
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552now deprecated to make names that don't begin with an alphabetic character, and
553aren't alphanumeric or contain other than a very few other characters,
72d4e865 554namely spaces, dashes, parentheses and colons. Because of the added meaning of
8c66a230 555C<\N> (See L</C<\N> experimental regex escape>), names that look like curly
72d4e865 556brace -enclosed quantifiers won't work. For example, C<\N{3,4}> now means to
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557match 3 to 4 non-newlines; before a custom name C<3,4> could have been created.
558
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559=item Deprecated Modules
560
561The following modules will be removed from the core distribution in a future
562release, and should be installed from CPAN instead. Distributions on CPAN
563which require these should add them to their prerequisites. The core versions
564of these modules warnings will issue a deprecation warning.
565
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566If you ship a packaged version of Perl, either alone or as part of a larger
567system, then you should carefully consider the reprecussions of core module
72d4e865 568deprecations. You may want to consider shipping your default build of
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569Perl with packages for some or all deprecated modules which install into
570C<vendor> or C<site> perl library directories. This will inhibit the
571deprecation warnings.
572
573Alternatively, you may want to consider patching F<lib/deprecate.pm>
574to provide deprecation warnings specific to your packaging system or
b951c6bd
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575distribution of Perl, consistent with how your packaging system or
576distribution manages a staged transition from a release where the
577installation of a single package provides the given functionality, to a later
578release where the system administrator needs to know to install multiple
579packages to get that same functionality.
8df7d2a3 580
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581=over
582
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583=item L<Class::ISA>
584
585=item L<Pod::Plainer>
586
587=item L<Shell>
3ab3a109 588
c66407fa 589=item L<Switch>
3ab3a109 590
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591Switch is buggy and should be avoided. You may find Perl's new
592C<given>/C<when> feature a suitable replacement. See L<perlsyn/"Switch
593statements"> for more information.
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594
595=back
596
3ab3a109
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597=item Assignment to $[
598
b6381718 599=item Use of the attribute :locked on subroutines
3ab3a109 600
b6381718 601=item Use of "locked" with the attributes pragma
3ab3a109 602
b6381718 603=item Use of "unique" with the attributes pragma
3ab3a109 604
b6381718 605=item Perl_pmflag
3ab3a109 606
b6381718
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607C<Perl_pmflag> is no longer part of Perl's public API. Calling it now
608generates a deprecation warning, and it will be removed in a future
609release. Although listed as part of the API, it was never documented,
610and only ever used in F<toke.c>, and prior to 5.10, F<regcomp.c>. In
611core, it has been replaced by a static function.
3ab3a109 612
b6381718 613=item Numerous Perl 4-era libraries
3ab3a109
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614
615F<termcap.pl>, F<tainted.pl>, F<stat.pl>, F<shellwords.pl>, F<pwd.pl>,
616F<open3.pl>, F<open2.pl>, F<newgetopt.pl>, F<look.pl>, F<find.pl>,
617F<finddepth.pl>, F<importenv.pl>, F<hostname.pl>, F<getopts.pl>,
618F<getopt.pl>, F<getcwd.pl>, F<flush.pl>, F<fastcwd.pl>, F<exceptions.pl>,
619F<ctime.pl>, F<complete.pl>, F<cacheout.pl>, F<bigrat.pl>, F<bigint.pl>,
620F<bigfloat.pl>, F<assert.pl>, F<abbrev.pl>, F<dotsh.pl>, and
621F<timelocal.pl> are all now deprecated. Using them will incur a warning.
622
b6381718 623
3ab3a109
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624=back
625
b6381718 626=head1 Unicode overhaul
3ab3a109 627
b6381718
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628Perl's developers have made a concerted effort to update Perl to be in
629sync with the latest Unicode standard. Changes for this include:
3ab3a109 630
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631Perl can now handle every Unicode character property. New documentation,
632L<perluniprops>, lists all available non-Unihan character properties. By
633default, perl does not expose Unihan, deprecated or Unicode-internal
634properties. See below for more details on these; there is also a section
635in the pod listing them, and explaining why they are not exposed.
3ab3a109 636
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637Perl now fully supports the Unicode compound-style of using C<=> and C<:>
638in writing regular expressions: C<\p{property=value}> and
639C<\p{property:value}> (both of which mean the same thing).
3ab3a109 640
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641Perl now fully supports the Unicode loose matching rules for text
642between the braces in C<\p{...}> constructs. In addition, Perl allows
643underscores between digits of numbers.
3ab3a109 644
b6381718 645Perl now accepts all the Unicode-defined synonyms for properties and property values.
3ab3a109 646
b6381718
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647C<qr/\X/>, which matches a Unicode logical character, has been expanded to work
648better with various Asian languages. It now is defined as an I<extended
649grapheme cluster>. (See L<http://www.unicode.org/reports/tr29/>).
650Anything matched previously and that made sense will continue to be
651accepted. Additionally:
3ab3a109 652
b6381718 653=over
3ab3a109 654
b6381718
JV
655=item *
656
657C<\X> will not break apart a C<S<CR LF>> sequence.
3ab3a109
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658
659=item *
660
b6381718
JV
661C<\X> will now match a sequence which includes the C<ZWJ> and C<ZWNJ> characters.
662
663=item *
3ab3a109 664
b6381718
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665C<\X> will now always match at least one character, including an initial mark.
666Marks generally come after a base character, but it is possible in Unicode to
667have them in isolation, and C<\X> will now handle that case, for example at the
668beginning of a line, or after a C<ZWSP>. And this is the part where C<\X>
669doesn't match the things that it used to that don't make sense. Formerly, for
670example, you could have the nonsensical case of an accented LF.
3ab3a109
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671
672=item *
673
b6381718
JV
674C<\X> will now match a (Korean) Hangul syllable sequence, and the Thai and Lao
675exception cases.
3ab3a109 676
b6381718 677=back
3ab3a109 678
a56dbb5e
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679Otherwise, this change should be transparent for the non-affected
680languages.
3ab3a109 681
b6381718 682C<\p{...}> matches using the Canonical_Combining_Class property were
a56dbb5e
JV
683completely broken in previous releases of Perl. They should now work
684correctly.
685
686Before Perl 5.12, the Unicode C<Decomposition_Type=Compat> property
687and a Perl extension had the same name, which led to neither matching
688all the correct values (with more than 100 mistakes in one, and several
689thousand in the other). The Perl extension has now been renamed to be
690C<Decomposition_Type=Noncanonical> (short: C<dt=noncanon>). It has the
691same meaning as was previously intended, namely the union of all the
692non-canonical Decomposition types, with Unicode C<Compat> being just
693one of those.
3ab3a109 694
b6381718 695C<\p{Decomposition_Type=Canonical}> now includes the Hangul syllables.
3ab3a109 696
a56dbb5e
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697C<\p{Uppercase}> and C<\p{Lowercase}> now work as the Unicode standard
698says they should. This means they each match a few more characters than
699they used to.
3ab3a109 700
a56dbb5e
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701C<\p{Cntrl}> now matches the same characters as C<\p{Control}>. This
702means it no longer will match Private Use (gc=co), Surrogates (gc=cs),
703nor Format (gc=cf) code points. The Format code points represent the
704biggest possible problem. All but 36 of them are either officially
705deprecated or strongly discouraged from being used. Of those 36, likely
706the most widely used are the soft hyphen (U+00AD), and BOM, ZWSP, ZWNJ,
707WJ, and similar characters, plus bidirectional controls.
3ab3a109 708
a56dbb5e
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709C<\p{Alpha}> now matches the same characters as C<\p{Alphabetic}>. Before
7105.12, Perl's definition definition included a number of things that aren't
711really alpha (all marks) while omitting many that were. The definitions
712of C<\p{Alnum}> and C<\p{Word}> depend on Alpha's definition and have
713changed accordingly.
3ab3a109 714
a56dbb5e
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715C<\p{Word}> no longer incorrectly matches non-word characters such
716as fractions.
3ab3a109 717
a56dbb5e
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718C<\p{Print}> no longer matches the line control characters: Tab, LF,
719CR, FF, VT, and NEL. This brings it in line with standards and the
720documentation.
3ab3a109 721
b6381718
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722C<\p{XDigit}> now matches the same characters as C<\p{Hex_Digit}>. This
723means that in addition to the characters it currently matches,
724C<[A-Fa-f0-9]>, it will also match the 22 fullwidth equivalents, for
725example U+FF10: FULLWIDTH DIGIT ZERO.
3ab3a109 726
b6381718
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727The Numeric type property has been extended to include the Unihan
728characters.
3ab3a109 729
b6381718
JV
730There is a new Perl extension, the 'Present_In', or simply 'In',
731property. This is an extension of the Unicode Age property, but
732C<\p{In=5.0}> matches any code point whose usage has been determined
733I<as of> Unicode version 5.0. The C<\p{Age=5.0}> only matches code points
734added in I<precisely> version 5.0.
3ab3a109 735
b6381718 736A number of properties now have the correct values for unassigned
a56dbb5e
JV
737code points. The affected properties are Bidi_Class, East_Asian_Width,
738Joining_Type, Decomposition_Type, Hangul_Syllable_Type, Numeric_Type,
739and Line_Break.
3ab3a109 740
b6381718
JV
741The Default_Ignorable_Code_Point, ID_Continue, and ID_Start properties
742are now up to date with current Unicode definitions.
3ab3a109 743
a56dbb5e
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744Earlier versions of Perl erroneously exposed certain properties that
745are supposed to be Unicode internal-only. Use of these in regular
746expressions will now generate, if enabled, a deprecation warning message.
b6381718
JV
747The properties are: Other_Alphabetic, Other_Default_Ignorable_Code_Point,
748Other_Grapheme_Extend, Other_ID_Continue, Other_ID_Start, Other_Lowercase,
749Other_Math, and Other_Uppercase.
3ab3a109 750
b6381718
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751It is now possible to change which Unicode properties Perl understands
752on a per-installation basis. As mentioned above, certain properties
753are turned off by default. These include all the Unihan properties
754(which should be accessible via the CPAN module Unicode::Unihan) and any
755deprecated or Unicode internal-only property that Perl has never exposed.
3ab3a109 756
b6381718 757The generated files in the C<lib/unicore/To> directory are now more
a56dbb5e
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758clearly marked as being stable, directly usable by applications. New hash
759entries in them give the format of the normal entries, which allows for
760easier machine parsing. Perl can generate files in this directory for
761any property, though most are suppressed. You can find instructions
762for changing which are written in L<perluniprops>.
3ab3a109 763
3ab3a109 764
3ab3a109 765
b6381718 766=head1 Modules and Pragmata
3ab3a109 767
a56dbb5e 768=head2 New Modules and Pragmata
3ab3a109 769
b6381718 770=over 4
3ab3a109 771
a56dbb5e 772=item C<autodie>
3ab3a109 773
b6381718
JV
774C<autodie> is a new lexically-scoped alternative for the C<Fatal> module.
775The bundled version is 2.06_01. Note that in this release, using a string
776eval when C<autodie> is in effect can cause the autodie behaviour to leak
777into the surrounding scope. See L<autodie/"BUGS"> for more details.
778
a56dbb5e 779Version 2.06_01 has been added to the Perl core.
3ab3a109 780
a56dbb5e 781=item C<Compress::Raw::Bzip2>
3ab3a109 782
a56dbb5e
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783Version 2.024 has been added to the Perl core.
784
785=item C<overloading>
3ab3a109 786
b6381718 787C<overloading> allows you to lexically disable or enable overloading
79849ba8 788for some or all operations.
3ab3a109 789
a56dbb5e
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790Version 0.001 has been added to the Perl core.
791
792=item C<parent>
b6381718
JV
793
794C<parent> establishes an ISA relationship with base classes at compile
795time. It provides the key feature of C<base> without further unwanted
796behaviors.
3ab3a109 797
a56dbb5e
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798Version 0.223 has been added to the Perl core.
799
800=item C<Parse::CPAN::Meta>
3ab3a109 801
a56dbb5e
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802Version 1.40 has been added to the Perl core.
803
804=item C<VMS::DCLsym>
805
806Version 1.03 has been added to the Perl core.
807
808=item C<VMS::Stdio>
809
810Version 2.4 has been added to the Perl core.
811
812=item C<XS::APItest::KeywordRPN>
813
814Version 0.003 has been added to the Perl core.
3ab3a109 815
b6381718 816=back
3ab3a109 817
a56dbb5e 818=head2 Updated Pragmata
3ab3a109 819
b6381718 820=over 4
3ab3a109 821
a56dbb5e
JV
822=item C<base>
823
824Upgraded from version 2.13 to 2.15.
825
826=item C<bignum>
827
828Upgraded from version 0.22 to 0.23.
829
830=item C<charnames>
b6381718
JV
831
832C<charnames> now contains the Unicode F<NameAliases.txt> database file.
833This has the effect of adding some extra C<\N> character names that
834formerly wouldn't have been recognised; for example, C<"\N{LATIN CAPITAL
835LETTER GHA}">.
3ab3a109 836
a56dbb5e
JV
837Upgraded from version 1.06 to 1.07.
838
839=item C<constant>
840
841Upgraded from version 1.13 to 1.20.
842
843=item C<diagnostics>
844
845C<diagnostics> now supports %.0f formatting internally.
846
847C<diagnostics> no longer suppresses C<Use of uninitialized value in range
848(or flip)> warnings. [perl #71204]
849
850Upgraded from version 1.17 to 1.19.
851
852=item C<feature>
3ab3a109 853
b6381718
JV
854In C<feature>, the meaning of the C<:5.10> and C<:5.10.X> feature bundles has
855changed slightly. The last component, if any (i.e. C<X>) is simply ignored.
856This is predicated on the assumption that new features will not, in
857general, be added to maintenance releases. So C<:5.10> and C<:5.10.X>
858have identical effect. This is a change to the behaviour documented for
8595.10.0.
3ab3a109 860
b6381718 861C<feature> now includes the C<unicode_strings> feature:
3ab3a109
JV
862
863 use feature "unicode_strings";
864
865This pragma turns on Unicode semantics for the case-changing operations
c66407fa
RS
866(C<uc>, C<lc>, C<ucfirst>, C<lcfirst>) on strings that don't have the
867internal UTF-8 flag set, but that contain single-byte characters between
868128 and 255.
3ab3a109 869
b7569deb 870Upgraded from version 1.11 to 1.16.
a56dbb5e
JV
871
872=item C<less>
873
874C<less> now includes the C<stash_name> method to allow subclasses of
875C<less> to pick where in %^H to store their stash.
876
877Upgraded from version 0.02 to 0.03.
878
879=item C<lib>
880
881Upgraded from version 0.5565 to 0.62.
882
883=item C<mro>
3ab3a109 884
b6381718
JV
885C<mro> is now implemented as an XS extension. The documented interface has not
886changed. Code relying on the implementation detail that some C<mro::>
887methods happened to be available at all times gets to "keep both pieces".
3ab3a109 888
a56dbb5e 889Upgraded from version 1.00 to 1.02.
3ab3a109 890
a56dbb5e 891=item C<overload>
3ab3a109 892
b6381718 893C<overload> now allow overloading of 'qr'.
3ab3a109 894
a56dbb5e 895Upgraded from version 1.06 to 1.10.
3ab3a109 896
a56dbb5e 897=item C<threads>
3ab3a109 898
a56dbb5e 899Upgraded from version 1.67 to 1.75.
3ab3a109 900
a56dbb5e
JV
901=item C<threads::shared>
902
903Upgraded from version 1.14 to 1.32.
904
905=item C<version>
3ab3a109 906
b6381718
JV
907C<version> now has support for L</Version number formats> as described earlier
908in this document and in its own documentation.
3ab3a109 909
a56dbb5e
JV
910Upgraded from version 0.74 to 0.82.
911
912=item C<warnings>
913
914C<warnings> has a new C<warnings::fatal_enabled()> function. It also
915includes a new C<illegalproto> warning category. See also L</New or
916Changed Diagnostics> for this change.
3ab3a109 917
a56dbb5e 918Upgraded from version 1.06 to 1.09.
3ab3a109
JV
919
920=back
921
a56dbb5e
JV
922=head2 Updated Modules
923
924=over 4
925
926=item C<Archive::Extract>
927
928Upgraded from version 0.24 to 0.38.
929
930=item C<Archive::Tar>
931
932Upgraded from version 1.38 to 1.54.
933
934=item C<Attribute::Handlers>
935
936Upgraded from version 0.79 to 0.87.
937
938=item C<AutoLoader>
939
940Upgraded from version 5.63 to 5.70.
941
942=item C<B::Concise>
943
944Upgraded from version 0.74 to 0.78.
945
946=item C<B::Debug>
947
948Upgraded from version 1.05 to 1.12.
949
950=item C<B::Deparse>
951
952Upgraded from version 0.83 to 0.94.
953
954=item C<B::Lint>
955
956Upgraded from version 1.09 to 1.11_01.
957
958=item C<CGI>
959
960Upgraded from version 3.29 to 3.48.
961
962=item C<Class::ISA>
963
964Upgraded from version 0.33 to 0.36.
965
966NOTE: C<Class::ISA> is deprecated and may be removed from a future version of Perl.
967
968=item C<Compress::Raw::Zlib>
969
970Upgraded from version 2.008 to 2.024.
971
972=item C<CPAN>
973
974Upgraded from version 1.9205 to 1.94_56.
975
976=item C<CPANPLUS>
977
978Upgraded from version 0.84 to 0.90.
979
980=item C<CPANPLUS::Dist::Build>
981
982Upgraded from version 0.06_02 to 0.46.
983
984=item C<Data::Dumper>
985
986Upgraded from version 2.121_14 to 2.125.
987
988=item C<DB_File>
989
990Upgraded from version 1.816_1 to 1.820.
991
992=item C<Devel::PPPort>
993
994Upgraded from version 3.13 to 3.19.
995
996=item C<Digest>
997
998Upgraded from version 1.15 to 1.16.
999
1000=item C<Digest::MD5>
1001
1002Upgraded from version 2.36_01 to 2.39.
1003
1004=item C<Digest::SHA>
1005
1006Upgraded from version 5.45 to 5.47.
1007
1008=item C<Encode>
1009
1010Upgraded from version 2.23 to 2.39.
1011
1012=item C<Exporter>
1013
1014Upgraded from version 5.62 to 5.64_01.
1015
1016=item C<ExtUtils::CBuilder>
1017
1018Upgraded from version 0.21 to 0.27.
1019
1020=item C<ExtUtils::Command>
1021
1022Upgraded from version 1.13 to 1.16.
1023
1024=item C<ExtUtils::Constant>
1025
1026Upgraded from version 0.2 to 0.22.
1027
1028=item C<ExtUtils::Install>
1029
1030Upgraded from version 1.44 to 1.55.
1031
1032=item C<ExtUtils::MakeMaker>
1033
1034Upgraded from version 6.42 to 6.56.
1035
1036=item C<ExtUtils::Manifest>
1037
1038Upgraded from version 1.51_01 to 1.57.
1039
1040=item C<ExtUtils::ParseXS>
1041
1042Upgraded from version 2.18_02 to 2.21.
1043
1044=item C<File::Fetch>
1045
1046Upgraded from version 0.14 to 0.24.
1047
1048=item C<File::Path>
1049
1050Upgraded from version 2.04 to 2.08_01.
1051
1052=item C<File::Temp>
1053
1054Upgraded from version 0.18 to 0.22.
1055
1056=item C<Filter::Simple>
1057
1058Upgraded from version 0.82 to 0.84.
1059
1060=item C<Filter::Util::Call>
1061
1062Upgraded from version 1.07 to 1.08.
1063
1064=item C<Getopt::Long>
1065
1066Upgraded from version 2.37 to 2.38.
1067
1068=item C<IO>
1069
1070Upgraded from version 1.23_01 to 1.25_02.
1071
1072=item C<IO::Zlib>
1073
1074Upgraded from version 1.07 to 1.10.
1075
1076=item C<IPC::Cmd>
1077
1078Upgraded from version 0.40_1 to 0.54.
1079
1080=item C<IPC::SysV>
1081
1082Upgraded from version 1.05 to 2.01.
1083
1084=item C<Locale::Maketext>
1085
1086Upgraded from version 1.12 to 1.14.
1087
1088=item C<Locale::Maketext::Simple>
1089
1090Upgraded from version 0.18 to 0.21.
1091
1092=item C<Log::Message>
1093
1094Upgraded from version 0.01 to 0.02.
1095
1096=item C<Log::Message::Simple>
1097
1098Upgraded from version 0.04 to 0.06.
1099
1100=item C<Math::BigInt>
1101
1102Upgraded from version 1.88 to 1.89_01.
1103
1104=item C<Math::BigInt::FastCalc>
1105
1106Upgraded from version 0.16 to 0.19.
1107
1108=item C<Math::BigRat>
1109
1110Upgraded from version 0.21 to 0.24.
1111
1112=item C<Math::Complex>
1113
1114Upgraded from version 1.37 to 1.56.
1115
1116=item C<Memoize>
1117
1118Upgraded from version 1.01_02 to 1.01_03.
1119
1120=item C<MIME::Base64>
1121
1122Upgraded from version 3.07_01 to 3.08.
1123
1124=item C<Module::Build>
1125
1126Upgraded from version 0.2808_01 to 0.3603.
1127
1128=item C<Module::CoreList>
1129
4cabf874 1130Upgraded from version 2.12 to 2.27.
a56dbb5e
JV
1131
1132=item C<Module::Load>
1133
1134Upgraded from version 0.12 to 0.16.
1135
1136=item C<Module::Load::Conditional>
1137
1138Upgraded from version 0.22 to 0.34.
1139
1140=item C<Module::Loaded>
1141
1142Upgraded from version 0.01 to 0.06.
1143
1144=item C<Module::Pluggable>
1145
1146Upgraded from version 3.6 to 3.9.
1147
1148=item C<Net::Ping>
1149
1150Upgraded from version 2.33 to 2.36.
1151
1152=item C<NEXT>
1153
1154Upgraded from version 0.60_01 to 0.64.
1155
1156=item C<Object::Accessor>
1157
1158Upgraded from version 0.32 to 0.36.
1159
1160=item C<Package::Constants>
1161
1162Upgraded from version 0.01 to 0.02.
1163
1164=item C<PerlIO>
1165
1166Upgraded from version 1.04 to 1.06.
1167
1168=item C<Pod::Parser>
1169
1170Upgraded from version 1.35 to 1.37.
1171
1172=item C<Pod::Perldoc>
1173
1174Upgraded from version 3.14_02 to 3.15_02.
1175
1176=item C<Pod::Plainer>
1177
1178Upgraded from version 0.01 to 1.02.
1179
1180NOTE: C<Pod::Plainer> is deprecated and may be removed from a future version of Perl.
1181
1182=item C<Pod::Simple>
1183
1184Upgraded from version 3.05 to 3.13.
1185
1186=item C<Safe>
1187
1188Upgraded from version 2.12 to 2.22.
1189
1190=item C<SelfLoader>
1191
1192Upgraded from version 1.11 to 1.17.
1193
1194=item C<Storable>
1195
1196Upgraded from version 2.18 to 2.22.
1197
1198=item C<Switch>
1199
1200Upgraded from version 2.13 to 2.16.
1201
1202NOTE: C<Switch> is deprecated and may be removed from a future version of Perl.
1203
1204=item C<Sys::Syslog>
1205
1206Upgraded from version 0.22 to 0.27.
1207
1208=item C<Term::ANSIColor>
1209
1210Upgraded from version 1.12 to 2.02.
1211
1212=item C<Term::UI>
1213
1214Upgraded from version 0.18 to 0.20.
1215
1216=item C<Test>
1217
1218Upgraded from version 1.25 to 1.25_02.
1219
1220=item C<Test::Harness>
1221
1222Upgraded from version 2.64 to 3.17.
1223
1224=item C<Test::Simple>
1225
1226Upgraded from version 0.72 to 0.94.
1227
1228=item C<Text::Balanced>
1229
1230Upgraded from version 2.0.0 to 2.02.
1231
1232=item C<Text::ParseWords>
1233
1234Upgraded from version 3.26 to 3.27.
1235
1236=item C<Text::Soundex>
1237
1238Upgraded from version 3.03 to 3.03_01.
1239
1240=item C<Thread::Queue>
1241
1242Upgraded from version 2.00 to 2.11.
1243
1244=item C<Thread::Semaphore>
1245
1246Upgraded from version 2.01 to 2.09.
1247
1248=item C<Tie::RefHash>
1249
1250Upgraded from version 1.37 to 1.38.
1251
1252=item C<Time::HiRes>
1253
1254Upgraded from version 1.9711 to 1.9719.
1255
1256=item C<Time::Local>
1257
1258Upgraded from version 1.18 to 1.1901_01.
1259
1260=item C<Time::Piece>
1261
1262Upgraded from version 1.12 to 1.15.
1263
1264=item C<Unicode::Collate>
1265
1266Upgraded from version 0.52 to 0.52_01.
1267
1268=item C<Unicode::Normalize>
1269
1270Upgraded from version 1.02 to 1.03.
1271
1272=item C<Win32>
1273
1274Upgraded from version 0.34 to 0.39.
1275
1276=item C<Win32API::File>
1277
1278Upgraded from version 0.1001_01 to 0.1101.
1279
1280=item C<XSLoader>
1281
1282Upgraded from version 0.08 to 0.10.
1283
1284=back
3ab3a109 1285
b6381718 1286=head2 Removed Modules and Pragmata
3ab3a109
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1287
1288=over 4
1289
a56dbb5e 1290=item C<attrs>
3ab3a109 1291
a56dbb5e 1292Removed from the Perl core. Prior version was 1.02.
3ab3a109 1293
a56dbb5e 1294=item C<CPAN::API::HOWTO>
3ab3a109 1295
a56dbb5e
JV
1296Removed from the Perl core. Prior version was 'undef'.
1297
1298=item C<CPAN::DeferedCode>
1299
1300Removed from the Perl core. Prior version was 5.50.
1301
1302=item C<CPANPLUS::inc>
1303
1304Removed from the Perl core. Prior version was 'undef'.
1305
1306=item C<DCLsym>
1307
1308Removed from the Perl core. Prior version was 1.03.
1309
1310=item C<ExtUtils::MakeMaker::bytes>
1311
1312Removed from the Perl core. Prior version was 6.42.
1313
1314=item C<ExtUtils::MakeMaker::vmsish>
1315
1316Removed from the Perl core. Prior version was 6.42.
3ab3a109 1317
a56dbb5e
JV
1318=item C<Stdio>
1319
1320Removed from the Perl core. Prior version was 2.3.
1321
1322=item C<Test::Harness::Assert>
1323
1324Removed from the Perl core. Prior version was 0.02.
1325
1326=item C<Test::Harness::Iterator>
1327
1328Removed from the Perl core. Prior version was 0.02.
1329
1330=item C<Test::Harness::Point>
1331
1332Removed from the Perl core. Prior version was 0.01.
1333
1334=item C<Test::Harness::Results>
1335
1336Removed from the Perl core. Prior version was 0.01.
1337
1338=item C<Test::Harness::Straps>
1339
1340Removed from the Perl core. Prior version was 0.26_01.
1341
1342=item C<Test::Harness::Util>
1343
1344Removed from the Perl core. Prior version was 0.01.
1345
1346=item C<XSSymSet>
1347
1348Removed from the Perl core. Prior version was 1.1.
3ab3a109
JV
1349
1350=back
1351
b6381718
JV
1352=head2 Deprecated Modules and Pragmata
1353
1354See L</Deprecated Modules> above.
1355
a56dbb5e 1356
3ab3a109
JV
1357=head1 Documentation
1358
1359=head2 New Documentation
1360
1361=over 4
1362
1363=item *
1364
b6381718 1365L<perlhaiku> contains instructions on how to build perl for the Haiku platform.
3ab3a109
JV
1366
1367=item *
1368
b6381718 1369L<perlmroapi> describes the new interface for pluggable Method Resolution Orders.
3ab3a109
JV
1370
1371=item *
1372
b6381718 1373L<perlperf>, by Richard Foley, provides an introduction to the use of
3ab3a109
JV
1374performance and optimization techniques which can be used with particular
1375reference to perl programs.
1376
1377=item *
1378
b6381718 1379L<perlrepository> describes how to access the perl source using the I<git> version
3ab3a109
JV
1380control system.
1381
1382=item *
1383
1384L<perlpolicy> extends the "Social contract about contributed modules" into
1385the beginnings of a document on Perl porting policies.
1386
1387=back
1388
1389=head2 Changes to Existing Documentation
1390
b6381718 1391
72d4e865
JV
1392=over
1393
1394
1395=item *
1396
3ab3a109
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1397The various large F<Changes*> files (which listed every change made to perl
1398over the last 18 years) have been removed, and replaced by a small file,
1399also called F<Changes>, which just explains how that same information may
1400be extracted from the git version control system.
1401
72d4e865
JV
1402=item *
1403
b6381718 1404F<Porting/patching.pod> has been deleted, as it mainly described
3ab3a109
JV
1405interacting with the old Perforce-based repository, which is now obsolete.
1406Information still relevant has been moved to L<perlrepository>.
1407
3ab3a109 1408
72d4e865
JV
1409=item *
1410
1411The syntax C<unless (EXPR) BLOCK else BLOCK> is now documented as valid, as
1412is the syntax C<unless (EXPR) BLOCK elsif (EXPR) BLOCK ... else BLOCK>,
1413although actually using the latter may not be the best idea for the
1414readability of your source code.
1415
3ab3a109
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1416
1417=item *
1418
1419Documented -X overloading.
1420
1421=item *
1422
1423Documented that C<when()> treats specially most of the filetest operators
1424
1425=item *
1426
b6381718 1427Documented C<when> as a syntax modifier.
3ab3a109
JV
1428
1429=item *
1430
c66407fa 1431Eliminated "Old Perl threads tutorial", which described 5005 threads.
3ab3a109
JV
1432
1433F<pod/perlthrtut.pod> is the same material reworked for ithreads.
1434
1435=item *
1436
1437Correct previous documentation: v-strings are not deprecated
1438
72d4e865 1439With version objects, we need them to use MODULE VERSION syntax. This
c66407fa 1440patch removes the deprecation notice.
3ab3a109
JV
1441
1442=item *
1443
b6381718
JV
1444Security contact information is now part of L<perlsec>.
1445
1446=item *
3ab3a109
JV
1447
1448A significant fraction of the core documentation has been updated to clarify
1449the behavior of Perl's Unicode handling.
1450
1451Much of the remaining core documentation has been reviewed and edited
1452for clarity, consistent use of language, and to fix the spelling of Tom
1453Christiansen's name.
1454
b6381718
JV
1455=item *
1456
3ab3a109 1457The Pod specification (L<perlpodspec>) has been updated to bring the
c66407fa 1458specification in line with modern usage already supported by most Pod
72d4e865
JV
1459systems. A parameter string may now follow the format name in a
1460"begin/end" region. Links to URIs with a text description are now
1461allowed. The usage of C<LE<lt>"section"E<gt>> has been marked as
c66407fa 1462deprecated.
3ab3a109 1463
b6381718
JV
1464=item *
1465
3ab3a109 1466L<if.pm|if> has been documented in L<perlfunc/use> as a means to get
c66407fa
RS
1467conditional loading of modules despite the implicit BEGIN block around
1468C<use>.
3ab3a109
JV
1469
1470=item *
1471
c66407fa 1472The documentation for C<$1> in perlvar.pod has been clarified.
3ab3a109 1473
a620a577
KW
1474=item *
1475
1476C<\N{U+I<wide hex char>}> is now documented.
1477
3ab3a109
JV
1478=back
1479
b6381718 1480=head1 Selected Performance Enhancements
3ab3a109
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1481
1482=over 4
1483
1484=item *
1485
1486A new internal cache means that C<isa()> will often be faster.
1487
1488=item *
1489
1490The implementation of C<C3> Method Resolution Order has been optimised -
1491linearisation for classes with single inheritance is 40% faster. Performance
1492for multiple inheritance is unchanged.
1493
1494=item *
1495
1496Under C<use locale>, the locale-relevant information is now cached on
1497read-only values, such as the list returned by C<keys %hash>. This makes
1498operations such as C<sort keys %hash> in the scope of C<use locale> much
1499faster.
1500
1501=item *
1502
1503Empty C<DESTROY> methods are no longer called.
1504
1505=item *
1506
b6381718 1507C<Perl_sv_utf8_upgrade()> is now faster.
3ab3a109
JV
1508
1509=item *
1510
b6381718 1511C<keys> on empty hash is now faster.
3ab3a109
JV
1512
1513=item *
1514
b6381718 1515C<if (%foo)> has been optimized to be faster than C<if (keys %foo)>.
3ab3a109
JV
1516
1517=item *
1518
8a4f3f14
VP
1519The string repetition operator (C<$str x $num>) is now several times faster
1520when C<$str> has length one or C<$num> is large.
1521
1522=item *
1523
3ab3a109
JV
1524Reversing an array to itself (as in C<@a = reverse @a>) in void context
1525now happens in-place and is several orders of magnitude faster than it
1526used to be. It will also preserve non-existent elements whenever
1527possible, i.e. for non magical arrays or tied arrays with C<EXISTS> and
1528C<DELETE> methods.
1529
1530=back
1531
1532=head1 Installation and Configuration Improvements
1533
72d4e865
JV
1534=over 4
1535
1536=item *
1537
1538L<perlapi>, L<perlintern>, L<perlmodlib> and L<perltoc> are now all
1539generated at build time, rather than being shipped as part of the release.
1540
1541=item *
3ab3a109
JV
1542
1543If C<vendorlib> and C<vendorarch> are the same, then they are only added to
1544C<@INC> once.
1545
72d4e865
JV
1546=item *
1547
3ab3a109
JV
1548C<$Config{usedevel}> and the C-level C<PERL_USE_DEVEL> are now defined if
1549perl is built with C<-Dusedevel>.
1550
72d4e865
JV
1551=item *
1552
3ab3a109
JV
1553F<Configure> will enable use of C<-fstack-protector>, to provide protection
1554against stack-smashing attacks, if the compiler supports it.
1555
72d4e865
JV
1556=item *
1557
3ab3a109 1558F<Configure> will now determine the correct prototypes for re-entrant
c66407fa 1559functions and for C<gconvert> if you are using a C++ compiler rather
3ab3a109
JV
1560than a C compiler.
1561
72d4e865
JV
1562=item *
1563
3ab3a109
JV
1564On Unix, if you build from a tree containing a git repository, the
1565configuration process will note the commit hash you have checked out, for
1566display in the output of C<perl -v> and C<perl -V>. Unpushed local commits
1567are automatically added to the list of local patches displayed by
1568C<perl -V>.
1569
72d4e865
JV
1570=item *
1571
b6381718 1572Perl now supports SystemTap's C<dtrace> compatibility layer and an
72d4e865
JV
1573issue with linking C<miniperl> has been fixed in the process.
1574
1575=item *
1576
b6381718
JV
1577perldoc now uses C<less -R> instead of C<less> for improved behaviour
1578in the face of C<groff>'s new usage of ANSI escape codes.
72d4e865
JV
1579
1580=item *
1581
72d4e865 1582
b6381718
JV
1583C<perl -V> now reports use of the compile-time options C<USE_PERL_ATOF> and
1584C<USE_ATTRIBUTES_FOR_PERLIO>.
72d4e865 1585
b6381718 1586=item *
3ab3a109
JV
1587
1588As part of the flattening of F<ext>, all extensions on all platforms are
1589built by F<make_ext.pl>. This replaces the Unix-specific
1590F<ext/util/make_ext>, VMS-specific F<make_ext.com> and Win32-specific
1591F<win32/buildext.pl>.
1592
b6381718 1593=back
3ab3a109 1594
b6381718
JV
1595=head1 Internal Changes
1596
1597Each release of Perl sees numerous internal changes which shouldn't
1598affect day to day usage but may still be notable for developers working
1599with Perl's source code.
1600
1601=over
3ab3a109
JV
1602
1603=item *
1604
b6381718
JV
1605The J.R.R. Tolkien quotes at the head of C source file have been checked and
1606proper citations added, thanks to a patch from Tom Christiansen.
3ab3a109
JV
1607
1608=item *
1609
b6381718
JV
1610The internal structure of the dual-life modules traditionally found in
1611the F<lib/> and F<ext/> directories y in the perl source has changed
1612significantly. Where possible, dual-lifed modules have been extracted
1613from F<lib/> and F<ext/>.
1614
1615Dual-lifed modules maintained by Perl's developers as part of the Perl
1616core now live in F<dist/>. Dual-lifed modules maintained primarily on
1617CPAN now live in F<cpan/>. When reporting a bug in a module located
1618under F<cpan/>, please send your bug report directly to the module's
1619bug tracker or author, rather than Perl's bug tracker.
3ab3a109
JV
1620
1621=item *
1622
b6381718
JV
1623C<\N{...}> now compiles better, always forces UTF-8 internal representation
1624
1625Perl's developers have fixed several problems with the recognition of C<\N{...}>
1626constructs. As part of this, perl will store any scalar or regex containing
1627C<\N{I<name>}> or C<\N{U+I<wide hex char>}> in its definition in
1628UTF-8 format. (This was true previously for all occurences of C<\N{I<name>}>
1629that did not use a custom translator, but now it's always true.)
3ab3a109
JV
1630
1631=item *
1632
b6381718 1633Perl_magic_setmglob now knows about globs, fixing RT #71254.
3ab3a109
JV
1634
1635=item *
1636
b6381718 1637C<SVt_RV> no longer exists. RVs are now stored in IVs.
3ab3a109
JV
1638
1639=item *
1640
b6381718 1641REGEXPs are now first class.
3ab3a109
JV
1642
1643=item *
1644
1645C<Perl_vcroak()> now accepts a null first argument. In addition, a full audit
1646was made of the "not NULL" compiler annotations, and those for several
1647other internal functions were corrected.
1648
1649=item *
1650
1651New macros C<dSAVEDERRNO>, C<dSAVE_ERRNO>, C<SAVE_ERRNO>, C<RESTORE_ERRNO>
1652have been added to formalise the temporary saving of the C<errno>
1653variable.
1654
1655=item *
1656
1657The function C<Perl_sv_insert_flags> has been added to augment
1658C<Perl_sv_insert>.
1659
1660=item *
1661
1662The function C<Perl_newSV_type(type)> has been added, equivalent to
1663C<Perl_newSV()> followed by C<Perl_sv_upgrade(type)>.
1664
1665=item *
1666
1667The function C<Perl_newSVpvn_flags()> has been added, equivalent to
1668C<Perl_newSVpvn()> and then performing the action relevant to the flag.
1669
1670Two flag bits are currently supported.
1671
1672=over 4
1673
1674=item *
1675
b6381718 1676C<SVf_UTF8> will call C<SvUTF8_on()> for you. (Note that this does not convert an
3ab3a109
JV
1677sequence of ISO 8859-1 characters to UTF-8). A wrapper, C<newSVpvn_utf8()>
1678is available for this.
1679
1680=item *
1681
b6381718 1682C<SVs_TEMP> now calls C<Perl_sv_2mortal()> on the new SV.
3ab3a109
JV
1683
1684=back
1685
1686There is also a wrapper that takes constant strings, C<newSVpvs_flags()>.
1687
1688=item *
1689
1690The function C<Perl_croak_xs_usage> has been added as a wrapper to
1691C<Perl_croak>.
1692
1693=item *
1694
b6381718 1695Perl now exports the functions C<PerlIO_find_layer> and C<PerlIO_list_alloc>.
3ab3a109
JV
1696
1697=item *
1698
1699C<PL_na> has been exterminated from the core code, replaced by local STRLEN
1700temporaries, or C<*_nolen()> calls. Either approach is faster than C<PL_na>,
17270880 1701which is a pointer dereference into the interpreter structure under ithreads,
3ab3a109
JV
1702and a global variable otherwise.
1703
1704=item *
1705
1706C<Perl_mg_free()> used to leave freed memory accessible via C<SvMAGIC()> on
1707the scalar. It now updates the linked list to remove each piece of magic
1708as it is freed.
1709
1710=item *
1711
1712Under ithreads, the regex in C<PL_reg_curpm> is now reference counted. This
1713eliminates a lot of hackish workarounds to cope with it not being reference
1714counted.
1715
1716=item *
1717
1718C<Perl_mg_magical()> would sometimes incorrectly turn on C<SvRMAGICAL()>.
1719This has been fixed.
1720
1721=item *
1722
1723The I<public> IV and NV flags are now not set if the string value has
1724trailing "garbage". This behaviour is consistent with not setting the
1725public IV or NV flags if the value is out of range for the type.
1726
1727=item *
1728
3ab3a109
JV
1729Uses of C<Nullav>, C<Nullcv>, C<Nullhv>, C<Nullop>, C<Nullsv> etc have been
1730replaced by C<NULL> in the core code, and non-dual-life modules, as C<NULL>
1731is clearer to those unfamiliar with the core code.
1732
1733=item *
1734
1735A macro C<MUTABLE_PTR(p)> has been added, which on (non-pedantic) gcc will
1736not cast away C<const>, returning a C<void *>. Macros C<MUTABLE_SV(av)>,
1737C<MUTABLE_SV(cv)> etc build on this, casting to C<AV *> etc without
1738casting away C<const>. This allows proper compile-time auditing of
1739C<const> correctness in the core, and helped picked up some errors (now
1740fixed).
1741
1742=item *
1743
1744Macros C<mPUSHs()> and C<mXPUSHs()> have been added, for pushing SVs on the
1745stack and mortalizing them.
1746
1747=item *
1748
1749Use of the private structure C<mro_meta> has changed slightly. Nothing
1750outside the core should be accessing this directly anyway.
1751
b6381718
JV
1752=item *
1753
1754A new tool, F<Porting/expand-macro.pl> has been added, that allows you
1755to view how a C preprocessor macro would be expanded when compiled.
1756This is handy when trying to decode the macro hell that is the perl
1757guts.
1758
1759=back
1760
1761=head1 Testing
1762
1763=head2 Testing improvements
1764
1765=over 4
1766
1767=item Parallel tests
1768
1769The core distribution can now run its regression tests in parallel on
1770Unix-like platforms. Instead of running C<make test>, set C<TEST_JOBS> in
1771your environment to the number of tests to run in parallel, and run
1772C<make test_harness>. On a Bourne-like shell, this can be done as
1773
1774 TEST_JOBS=3 make test_harness # Run 3 tests in parallel
3ab3a109 1775
b6381718
JV
1776An environment variable is used, rather than parallel make itself, because
1777L<TAP::Harness> needs to be able to schedule individual non-conflicting test
1778scripts itself, and there is no standard interface to C<make> utilities to
1779interact with their job schedulers.
3ab3a109 1780
b6381718
JV
1781Note that currently some test scripts may fail when run in parallel (most
1782notably C<ext/IO/t/io_dir.t>). If necessary run just the failing scripts
1783again sequentially and see if the failures go away.
3ab3a109 1784
b6381718 1785=item Test harness flexibility
3ab3a109 1786
b6381718
JV
1787It's now possible to override C<PERL5OPT> and friends in F<t/TEST>
1788
1789=item Test watchdog
3ab3a109 1790
3ab3a109
JV
1791Several tests that have the potential to hang forever if they fail now
1792incorporate a "watchdog" functionality that will kill them after a timeout,
1793which helps ensure that C<make test> and C<make test_harness> run to
79849ba8 1794completion automatically.
3ab3a109 1795
b6381718
JV
1796
1797=back
1798
1799=head2 New Tests
1800
1801Perl's developers have added a number of new tests to the core.
1802In addition to the items listed below, many modules updated from CPAN
1803incorporate new tests.
3ab3a109
JV
1804
1805=over 4
1806
1807=item *
1808
1809Significant cleanups to core tests to ensure that language and
1810interpreter features are not used before they're tested.
1811
1812=item *
1813
c66407fa
RS
1814C<make test_porting> now runs a number of important pre-commit checks
1815which might be of use to anyone working on the Perl core.
3ab3a109
JV
1816
1817=item *
1818
1819F<t/porting/podcheck.t> automatically checks the well-formedness of
1820POD found in all .pl, .pm and .pod files in the F<MANIFEST>, other than in
1821dual-lifed modules which are primarily maintained outside the Perl core.
1822
1823=item *
1824
1825F<t/porting/manifest.t> now tests that all files listed in MANIFEST are present.
1826
1827=item *
1828
b6381718 1829F<t/op/while_readdir.t> tests that a bare readdir in while loop sets $_.
3ab3a109
JV
1830
1831=item *
1832
b6381718 1833F<t/comp/retainedlines.t> checks that the debugger can retain source lines from C<eval>.
3ab3a109
JV
1834
1835=item *
1836
b6381718 1837F<t/io/perlio_fail.t> checks that bad layers fail.
3ab3a109
JV
1838
1839=item *
1840
b6381718 1841F<t/io/perlio_leaks.t> checks that PerlIO layers are not leaking.
3ab3a109
JV
1842
1843=item *
1844
b6381718 1845F<t/io/perlio_open.t> checks that certain special forms of open work.
3ab3a109
JV
1846
1847=item *
1848
b6381718 1849F<t/io/perlio.t> includes general PerlIO tests.
3ab3a109
JV
1850
1851=item *
1852
b6381718 1853F<t/io/pvbm.t> checks that there is no unexpected interaction between the internal types
3ab3a109
JV
1854C<PVBM> and C<PVGV>.
1855
1856=item *
1857
b6381718 1858F<t/mro/package_aliases.t> checks that mro works properly in the presence of aliased packages.
3ab3a109
JV
1859
1860=item *
1861
b6381718 1862F<t/op/dbm.t> tests C<dbmopen> and C<dbmclose>.
3ab3a109
JV
1863
1864=item *
1865
b6381718 1866F<t/op/index_thr.t> tests the interaction of C<index> and threads.
3ab3a109
JV
1867
1868=item *
1869
b6381718 1870F<t/op/pat_thr.t> tests the interaction of esoteric patterns and threads.
3ab3a109
JV
1871
1872=item *
1873
b6381718 1874F<t/op/qr_gc.t> tests that C<qr> doesn't leak.
3ab3a109
JV
1875
1876=item *
1877
b6381718 1878F<t/op/reg_email_thr.t> tests the interaction of regex recursion and threads.
3ab3a109
JV
1879
1880=item *
1881
b6381718 1882F<t/op/regexp_qr_embed_thr.t> tests the interaction of patterns with embedded C<qr//> and threads.
3ab3a109
JV
1883
1884=item *
1885
b6381718 1886F<t/op/regexp_unicode_prop.t> tests Unicode properties in regular expressions.
3ab3a109
JV
1887
1888=item *
1889
b6381718 1890F<t/op/regexp_unicode_prop_thr.t> tests the interaction of Unicode properties and threads.
3ab3a109
JV
1891
1892=item *
1893
b6381718 1894F<t/op/reg_nc_tie.t> tests the tied methods of C<Tie::Hash::NamedCapture>.
3ab3a109
JV
1895
1896=item *
1897
b6381718 1898F<t/op/reg_posixcc.t> checks that POSIX character classes behave consistently.
3ab3a109
JV
1899
1900=item *
1901
0c359e6f 1902F<t/op/re.t> checks that exportable C<re> functions in F<universal.c> work.
3ab3a109
JV
1903
1904=item *
1905
b6381718 1906F<t/op/setpgrpstack.t> checks that C<setpgrp> works.
3ab3a109
JV
1907
1908=item *
1909
b6381718 1910F<t/op/substr_thr.t> tests the interaction of C<substr> and threads.
3ab3a109
JV
1911
1912=item *
1913
b6381718 1914F<t/op/upgrade.t> checks that upgrading and assigning scalars works.
3ab3a109
JV
1915
1916=item *
1917
b6381718 1918F<t/uni/lex_utf8.t> checks that Unicode in the lexer works.
3ab3a109
JV
1919
1920=item *
1921
b6381718 1922F<t/uni/tie.t> checks that Unicode and C<tie> work.
3ab3a109
JV
1923
1924=item *
1925
b6381718 1926F<t/comp/final_line_num.t> tests whether line numbers are correct at EOF
3ab3a109
JV
1927
1928=item *
1929
b6381718 1930F<t/comp/form_scope.t> tests format scoping.
3ab3a109
JV
1931
1932=item *
1933
b6381718 1934F<t/comp/line_debug.t> tests whether C<< @{"_<$file"} >> works.
3ab3a109
JV
1935
1936=item *
1937
b6381718 1938F<t/op/filetest_t.t> tests if -t file test works.
3ab3a109
JV
1939
1940=item *
1941
b6381718 1942F<t/op/qr.t> tests C<qr>.
3ab3a109
JV
1943
1944=item *
1945
b6381718 1946F<t/op/utf8cache.t> tests malfunctions of the utf8 cache.
3ab3a109
JV
1947
1948=item *
1949
b6381718 1950F<t/re/uniprops.t> test unicodes C<\p{}> regex constructs.
3ab3a109 1951
b16f1257
JV
1952=item *
1953
b6381718
JV
1954F<t/op/filehandle.t> tests some suitably portable filetest operators
1955to check that they work as expected, particularly in the light of some
1956internal changes made in how filehandles are blessed.
72d4e865 1957
b16f1257
JV
1958=item *
1959
b6381718
JV
1960F<t/op/time_loop.t> tests that unix times greater than C<2**63>, which
1961can now be handed to C<gmtime> and C<localtime>, do not cause an internal
1962overflow or an excessively long loop.
72d4e865 1963
3ab3a109
JV
1964=back
1965
3ab3a109 1966
b6381718 1967=head1 New or Changed Diagnostics
72d4e865 1968
b6381718 1969=head2 New Diagnostics
72d4e865 1970
b6381718 1971=over
72d4e865 1972
b6381718 1973=item *
72d4e865 1974
b6381718
JV
1975SV allocation tracing has been added to the diagnostics enabled by C<-Dm>.
1976The tracing can alternatively output via the C<PERL_MEM_LOG> mechanism, if
1977that was enabled when the F<perl> binary was compiled.
72d4e865 1978
b6381718 1979=item *
3ab3a109 1980
b6381718
JV
1981Smartmatch resolution tracing has been added as a new diagnostic. Use C<-DM> to
1982enable it.
3ab3a109 1983
b6381718 1984=item *
3ab3a109 1985
b6381718
JV
1986A new debugging flag C<-DB> now dumps subroutine definitions, leaving
1987C<-Dx> for its original purpose of dumping syntax trees.
3ab3a109 1988
b6381718 1989=item *
3ab3a109 1990
b6381718
JV
1991Perl 5.12 provides a number of new diagnostic messages to help you write
1992better code. See L<perldiag> for details of these new messages.
3ab3a109
JV
1993
1994=over 4
1995
1996=item *
1997
1998C<Bad plugin affecting keyword '%s'>
1999
2000=item *
2001
2002C<gmtime(%.0f) too large>
2003
2004=item *
2005
2006C<Lexing code attempted to stuff non-Latin-1 character into Latin-1 input>
2007
2008=item *
2009
2010C<Lexing code internal error (%s)>
2011
2012=item *
2013
2014C<localtime(%.0f) too large>
2015
2016=item *
2017
2018C<Overloaded dereference did not return a reference>
2019
2020=item *
2021
2022C<Overloaded qr did not return a REGEXP>
2023
2024=item *
2025
2026C<Perl_pmflag() is deprecated, and will be removed from the XS API>
2027
2028=item *
2029
b6381718 2030C<lvalue attribute ignored after the subroutine has been defined>
3ab3a109
JV
2031
2032This new warning is issued when one attempts to mark a subroutine as
2033lvalue after it has been defined.
2034
2035=item *
2036
b6381718
JV
2037Perl now warns you if C<++> or C<--> are unable to change the value because it's
2038beyond the limit of representation.
3ab3a109
JV
2039
2040This uses a new warnings category: "imprecision".
2041
2042=item *
c66407fa
RS
2043
2044C<lc>, C<uc>, C<lcfirst>, and C<ucfirst> warn when passed undef.
3ab3a109
JV
2045
2046=item *
2047
b6381718 2048C<Show constant in "Useless use of a constant in void context">
3ab3a109
JV
2049
2050=item *
2051
b6381718 2052C<Prototype after '%s'>
3ab3a109
JV
2053
2054=item *
2055
b6381718
JV
2056C<panic: sv_chop %s>
2057
2058This new fatal error occurs when the C routine C<Perl_sv_chop()> was
2059passed a position that is not within the scalar's string buffer. This
2060could be caused by buggy XS code, and at this point recovery is not
2061possible.
2062
3ab3a109
JV
2063
2064=item *
2065
b6381718
JV
2066The fatal error C<Malformed UTF-8 returned by \N> is now produced if the
2067C<charnames> handler returns malformed UTF-8.
3ab3a109
JV
2068
2069=item *
2070
b6381718 2071If an unresolved named character or sequence was encountered when compiling a
7acb582f 2072regex pattern then the fatal error C<\N{NAME} must be resolved by the lexer>
b6381718 2073is now produced. This can happen, for example, when using a single-quotish
7acb582f 2074context like C<$re = '\N{SPACE}'; /$re/;>. See L<perldiag> for more examples of
b6381718 2075how the lexer can get bypassed.
3ab3a109
JV
2076
2077=item *
2078
7acb582f 2079C<Invalid hexadecimal number in \N{U+...}> is a new fatal error triggered when
b6381718
JV
2080the character constant represented by C<...> is not a valid hexadecimal
2081number.
3ab3a109
JV
2082
2083=item *
2084
b6381718
JV
2085The new meaning of C<\N> as C<[^\n]> is not valid in a bracketed character
2086class, just like C<.> in a character class loses its special meaning, and will
7acb582f 2087cause the fatal error C<\N in a character class must be a named character: \N{...}>.
b6381718
JV
2088
2089=item *
3ab3a109 2090
b6381718
JV
2091The rules on what is legal for the C<...> in C<\N{...}> have been tightened
2092up so that unless the C<...> begins with an alphabetic character and continues
2093with a combination of alphanumerics, dashes, spaces, parentheses or colons
7acb582f 2094then the warning C<Deprecated character(s) in \N{...} starting at '%s'> is
b6381718 2095now issued.
3ab3a109
JV
2096
2097=item *
2098
b6381718
JV
2099The warning C<Using just the first characters returned by \N{}> will be
2100issued if the C<charnames> handler returns a sequence of characters which
2101exceeds the limit of the number of characters that can be used. The message
2102will indicate which characters were used and which were discarded.
3ab3a109 2103
b6381718 2104=back
3ab3a109 2105
b6381718 2106=back
3ab3a109 2107
b6381718 2108=head2 Changed Diagnostics
3ab3a109 2109
b6381718 2110A number of existing diagnostic messages have been improved or corrected:
3ab3a109 2111
b6381718 2112=over
3ab3a109
JV
2113
2114=item *
2115
b6381718
JV
2116A new warning category C<illegalproto> allows finer-grained control of
2117warnings around function prototypes.
3ab3a109 2118
b6381718 2119The two warnings:
3ab3a109 2120
b6381718 2121=over
3ab3a109 2122
b6381718
JV
2123=item C<Illegal character in prototype for %s : %s>
2124
2125=item C<Prototype after '%c' for %s : %s>
2126
2127=back
2128
2129have been moved from the C<syntax> top-level warnings category into a new
2130first-level category, C<illegalproto>. These two warnings are currently the
2131only ones emitted during parsing of an invalid/illegal prototype, so one
2132can now do
2133
2134 no warnings 'illegalproto';
2135
2136to suppress only those, but not other syntax-related warnings. Warnings where
2137prototypes are changed, ignored, or not met are still in the C<prototype>
79849ba8 2138category as before.
3ab3a109
JV
2139
2140=item *
2141
3ab3a109
JV
2142C<Deep recursion on subroutine "%s">
2143
2144It is now possible to change the depth threshold for this warning from the
2145default of 100, by recompiling the F<perl> binary, setting the C
2146pre-processor macro C<PERL_SUB_DEPTH_WARN> to the desired value.
2147
2148=item *
2149
b6381718
JV
2150C<Illegal character in prototype> warning is now more precise
2151when reporting illegal characters after _
3ab3a109
JV
2152
2153=item *
2154
b6381718 2155mro merging error messages are now very similar to those produced by L<Algorithm::C3>.
3ab3a109
JV
2156
2157=item *
2158
b6381718
JV
2159Amelioration of the error message "Unrecognized character %s in column %d"
2160
2161Changes the error message to "Unrecognized character %s; marked by E<lt>--
2162HERE after %sE<lt>-- HERE near column %d". This should make it a little
2163simpler to spot and correct the suspicious character.
3ab3a109
JV
2164
2165=item *
2166
b6381718
JV
2167Perl now explicitly points to C<$.> when it causes an uninitialized warning for
2168ranges in scalar context.
3ab3a109
JV
2169
2170=item *
2171
b6381718 2172C<split> now warns when called in void context.
3ab3a109
JV
2173
2174=item *
2175
b6381718
JV
2176C<printf>-style functions called with too few arguments will now issue the
2177warning C<"Missing argument in %s"> [perl #71000]
3ab3a109
JV
2178
2179=item *
2180
b6381718
JV
2181Perl now properly returns a syntax error instead of segfaulting
2182if C<each>, C<keys>, or C<values> is used without an argument.
3ab3a109
JV
2183
2184=item *
2185
b6381718
JV
2186C<tell()> now fails properly if called without an argument and when no
2187previous file was read.
3ab3a109 2188
b6381718
JV
2189C<tell()> now returns C<-1>, and sets errno to C<EBADF>, thus restoring
2190the 5.8.x behaviour.
3ab3a109
JV
2191
2192=item *
2193
b6381718
JV
2194C<overload> no longer implicitly unsets fallback on repeated 'use
2195overload' lines.
3ab3a109 2196
72d4e865
JV
2197=item *
2198
b6381718 2199POSIX::strftime() can now handle Unicode characters in the format string.
72d4e865
JV
2200
2201=item *
2202
b6381718
JV
2203The C<syntax> category was removed from 5 warnings that should only be in
2204C<deprecated>.
72d4e865
JV
2205
2206=item *
2207
b6381718
JV
2208Three fatal C<pack>/C<unpack> error messages have been normalized to
2209C<panic: %s>
72d4e865
JV
2210
2211=item *
2212
b6381718
JV
2213C<Unicode character is illegal> has been rephrased to be more accurate
2214
2215It now reads C<Unicode non-character is illegal in interchange> and the
2216perldiag documentation has been expanded a bit.
72d4e865
JV
2217
2218=item *
2219
2220Currently, all but the first of the several characters that the C<charnames>
2221handler may return are discarded when used in a regular expression pattern
2222bracketed character class. If this happens then the warning C<Using just the
2223first character returned by \N{} in character class> will be issued.
2224
2225=item *
2226
7acb582f 2227The warning C<Missing right brace on \N{} or unescaped left brace after \N.
72d4e865
JV
2228Assuming the latter> will be issued if Perl encounters a C<\N{> but doesn't
2229find a matching C<}>. In this case Perl doesn't know if it was mistakenly
2230omitted, or if "match non-newline" followed by "match a C<{>" was desired.
2231It assumes the latter because that is actually a valid interpretation as
2232written, unlike the other case. If you meant the former, you need to add the
2233matching right brace. If you did mean the latter, you can silence this
2234warning by writing instead C<\N\{>.
2235
2236=item *
2237
2238C<gmtime> and C<localtime> called with numbers smaller than they can reliably
2239handle will now issue the warnings C<gmtime(%.0f) too small> and
2240C<localtime(%.0f) too small>.
2241
2242=back
3ab3a109 2243
b6381718 2244The following diagnostic messages have been removed:
c66407fa
RS
2245
2246=over 4
2247
2248=item *
2249
2250C<Runaway format>
2251
2252=item *
2253
2254C<Can't locate package %s for the parents of %s>
2255
b6381718 2256In general this warning it only got produced in
c66407fa
RS
2257conjunction with other warnings, and removing it allowed an ISA lookup
2258optimisation to be added.
2259
2260=item *
2261
2262C<v-string in use/require is non-portable>
2263
2264=back
2265
3ab3a109
JV
2266=head1 Utility Changes
2267
2268=over 4
2269
2270=item *
2271
b6381718 2272F<h2ph> now looks in C<include-fixed> too, which is a recent addition to gcc's
3ab3a109
JV
2273search path.
2274
2275=item *
2276
79849ba8
JV
2277F<h2xs> no longer incorrectly treats enum values like macros.
2278It also now handles C++ style comments (C<//>) properly in enums.
3ab3a109
JV
2279
2280=item *
2281
d13f8571
JD
2282F<perl5db.pl> now supports C<LVALUE> subroutines. Additionally, the
2283debugger now correctly handles proxy constant subroutines, and
2284subroutine stubs.
3ab3a109
JV
2285
2286=item *
2287
b6381718
JV
2288F<perlbug> now uses C<%Module::CoreList::bug_tracker> to print out
2289upstream bug tracker URLs. If a user identifies a particular module
4655b0a1 2290as the topic of their bug report and we're able to divine the URL for
b6381718
JV
2291its upstream bug tracker, perlbug now provide a message to the user
2292explaining that the core copies the CPAN version directly, and provide
2293the URL for reporting the bug directly to the upstream author.
3ab3a109 2294
b6381718 2295F<perlbug> no longer reports "Message sent" when it hasn't actually sent the message
3ab3a109
JV
2296
2297=item *
2298
b6381718
JV
2299F<perlthanks> is a new utility for sending non-bug-reports to the
2300authors and maintainers of Perl. Getting nothing but bug reports can
2301become a bit demoralising. If Perl 5.12 works well for you, please try
2302out F<perlthanks>. It will make the developers smile.
3ab3a109
JV
2303
2304=item *
2305
b6381718 2306Perl's developers have fixed bugs in F<a2p> having to do with the
e014eb68
JV
2307C<match()> operator in list context. Additionally, F<a2p> no longer
2308generates code that uses the C<$[> variable.
3ab3a109
JV
2309
2310=back
2311
2312=head1 Selected Bug Fixes
2313
2314=over 4
2315
2316=item *
2317
b6381718
JV
2318U+0FFFF is now a legal character in regular expressions.
2319
2320=item *
2321
2322pp_qr now always returns a new regexp SV. Resolves RT #69852.
3ab3a109
JV
2323
2324Instead of returning a(nother) reference to the (pre-compiled) regexp in the
2325optree, use reg_temp_copy() to create a copy of it, and return a reference to
2326that. This resolves issues about Regexp::DESTROY not being called in a timely
2327fashion (the original bug tracked by RT #69852), as well as bugs related to
2328blessing regexps, and of assigning to regexps, as described in correspondence
2329added to the ticket.
2330
2331It transpires that we also need to undo the SvPVX() sharing when ithreads
2332cloning a Regexp SV, because mother_re is set to NULL, instead of a cloned
2333copy of the mother_re. This change might fix bugs with regexps and threads in
2334certain other situations, but as yet neither tests nor bug reports have
2335indicated any problems, so it might not actually be an edge case that it's
2336possible to reach.
2337
2338=item *
2339
3ab3a109
JV
2340Several compilation errors and segfaults when perl was built with C<-Dmad> were fixed.
2341
2342=item *
2343
2344Fixes for lexer API changes in 5.11.2 which broke NYTProf's savesrc option.
2345
2346=item *
2347
c66407fa 2348C<-t> should only return TRUE for file handles connected to a TTY
3ab3a109 2349
c66407fa
RS
2350The Microsoft C version of C<isatty()> returns TRUE for all
2351character mode devices, including the F</dev/null>-style "nul"
3ab3a109
JV
2352device and printers like "lpt1".
2353
2354=item *
2355
2356Fixed a regression caused by commit fafafbaf which caused a panic during
2357parameter passing [perl #70171]
2358
2359=item *
2360
2361On systems which in-place edits without backup files, -i'*' now works as
2362the documentation says it does [perl #70802]
2363
2364=item *
2365
2366Saving and restoring magic flags no longer loses readonly flag.
2367
2368=item *
2369
2370The malformed syntax C<grep EXPR LIST> (note the missing comma) no longer
2371causes abrupt and total failure.
2372
2373=item *
2374
2375Regular expressions compiled with C<qr{}> literals properly set C<$'> when
2376matching again.
2377
2378=item *
2379
2380Using named subroutines with C<sort> should no longer lead to bus errors [perl
2381#71076]
2382
2383=item *
2384
2385Numerous bugfixes catch small issues caused by the recently-added Lexer API.
2386
2387=item *
2388
2389Smart match against C<@_> sometimes gave false negatives. [perl #71078]
2390
2391=item *
2392
c66407fa
RS
2393C<$@> may now be assigned a read-only value (without error or busting
2394the stack).
3ab3a109
JV
2395
2396=item *
2397
2398C<sort> called recursively from within an active comparison subroutine no
2399longer causes a bus error if run multiple times. [perl #71076]
2400
2401=item *
2402
c66407fa 2403Tie::Hash::NamedCapture::* will not abort if passed bad input (RT #71828)
3ab3a109
JV
2404
2405=item *
2406
2407@_ and $_ no longer leak under threads (RT #34342 and #41138, also
2408#70602, #70974)
2409
2410=item *
2411
2412C<-I> on shebang line now adds directories in front of @INC
2413as documented, and as does C<-I> when specified on the command-line.
2414
2415=item *
2416
2417C<kill> is now fatal when called on non-numeric process identifiers.
c66407fa
RS
2418Previously, an C<undef> process identifier would be interpreted as a
2419request to kill process 0, which would terminate the current process
72d4e865 2420group on POSIX systems. Since process identifiers are always integers,
c66407fa 2421killing a non-numeric process is now fatal.
3ab3a109
JV
2422
2423=item *
2424
24255.10.0 inadvertently disabled an optimisation, which caused a measurable
2426performance drop in list assignment, such as is often used to assign
2427function parameters from C<@_>. The optimisation has been re-instated, and
72d4e865 2428the performance regression fixed. (This fix is also present in 5.10.1)
3ab3a109
JV
2429
2430=item *
2431
2432Fixed memory leak on C<while (1) { map 1, 1 }> [RT #53038].
2433
2434=item *
2435
2436Some potential coredumps in PerlIO fixed [RT #57322,54828].
2437
2438=item *
2439
2440The debugger now works with lvalue subroutines.
2441
2442=item *
2443
2444The debugger's C<m> command was broken on modules that defined constants
2445[RT #61222].
2446
2447=item *
2448
2449C<crypt> and string complement could return tainted values for untainted
2450arguments [RT #59998].
2451
2452=item *
2453
2454The C<-i>I<.suffix> command-line switch now recreates the file using
2455restricted permissions, before changing its mode to match the original
2456file. This eliminates a potential race condition [RT #60904].
2457
2458=item *
2459
2460On some Unix systems, the value in C<$?> would not have the top bit set
2461(C<$? & 128>) even if the child core dumped.
2462
2463=item *
2464
2465Under some circumstances, C<$^R> could incorrectly become undefined
2466[RT #57042].
2467
2468=item *
2469
2470In the XS API, various hash functions, when passed a pre-computed hash where
2471the key is UTF-8, might result in an incorrect lookup.
2472
2473=item *
2474
2475XS code including F<XSUB.h> before F<perl.h> gave a compile-time error
2476[RT #57176].
2477
2478=item *
2479
2480C<< $object-E<gt>isa('Foo') >> would report false if the package C<Foo> didn't
2481exist, even if the object's C<@ISA> contained C<Foo>.
2482
2483=item *
2484
2485Various bugs in the new-to 5.10.0 mro code, triggered by manipulating
2486C<@ISA>, have been found and fixed.
2487
2488=item *
2489
2490Bitwise operations on references could crash the interpreter, e.g.
2491C<$x=\$y; $x |= "foo"> [RT #54956].
2492
2493=item *
2494
2495Patterns including alternation might be sensitive to the internal UTF-8
2496representation, e.g.
2497
2498 my $byte = chr(192);
2499 my $utf8 = chr(192); utf8::upgrade($utf8);
2500 $utf8 =~ /$byte|X}/i; # failed in 5.10.0
2501
2502=item *
2503
2504Within UTF8-encoded Perl source files (i.e. where C<use utf8> is in
2505effect), double-quoted literal strings could be corrupted where a C<\xNN>,
2506C<\0NNN> or C<\N{}> is followed by a literal character with ordinal value
2507greater than 255 [RT #59908].
2508
2509=item *
2510
2511C<B::Deparse> failed to correctly deparse various constructs:
2512C<readpipe STRING> [RT #62428], C<CORE::require(STRING)> [RT #62488],
2513C<sub foo(_)> [RT #62484].
2514
2515=item *
2516
2517Using C<setpgrp> with no arguments could corrupt the perl stack.
2518
2519=item *
2520
2521The block form of C<eval> is now specifically trappable by C<Safe> and
72d4e865 2522C<ops>. Previously it was erroneously treated like string C<eval>.
3ab3a109
JV
2523
2524=item *
2525
2526In 5.10.0, the two characters C<[~> were sometimes parsed as the smart
2527match operator (C<~~>) [RT #63854].
2528
2529=item *
2530
2531In 5.10.0, the C<*> quantifier in patterns was sometimes treated as
2532C<{0,32767}> [RT #60034, #60464]. For example, this match would fail:
2533
2534 ("ab" x 32768) =~ /^(ab)*$/
2535
2536=item *
2537
2538C<shmget> was limited to a 32 bit segment size on a 64 bit OS [RT #63924].
2539
2540=item *
2541
2542Using C<next> or C<last> to exit a C<given> block no longer produces a
2543spurious warning like the following:
2544
2545 Exiting given via last at foo.pl line 123
2546
2547=item *
2548
3ab3a109
JV
2549Assigning a format to a glob could corrupt the format; e.g.:
2550
2551 *bar=*foo{FORMAT}; # foo format now bad
2552
2553=item *
2554
2555Attempting to coerce a typeglob to a string or number could cause an
2556assertion failure. The correct error message is now generated,
2557C<Can't coerce GLOB to I<$type>>.
2558
2559=item *
2560
2561Under C<use filetest 'access'>, C<-x> was using the wrong access mode. This
2562has been fixed [RT #49003].
2563
2564=item *
2565
2566C<length> on a tied scalar that returned a Unicode value would not be
2567correct the first time. This has been fixed.
2568
2569=item *
2570
2571Using an array C<tie> inside in array C<tie> could SEGV. This has been
2572fixed. [RT #51636]
2573
2574=item *
2575
2576A race condition inside C<PerlIOStdio_close()> has been identified and
2577fixed. This used to cause various threading issues, including SEGVs.
2578
2579=item *
2580
2581In C<unpack>, the use of C<()> groups in scalar context was internally
2582placing a list on the interpreter's stack, which manifested in various
72d4e865 2583ways, including SEGVs. This is now fixed [RT #50256].
3ab3a109
JV
2584
2585=item *
2586
2587Magic was called twice in C<substr>, C<\&$x>, C<tie $x, $m> and C<chop>.
2588These have all been fixed.
2589
2590=item *
2591
2592A 5.10.0 optimisation to clear the temporary stack within the implicit
2593loop of C<s///ge> has been reverted, as it turned out to be the cause of
2594obscure bugs in seemingly unrelated parts of the interpreter [commit
2595ef0d4e17921ee3de].
2596
2597=item *
2598
2599The line numbers for warnings inside C<elsif> are now correct.
2600
2601=item *
2602
2603The C<..> operator now works correctly with ranges whose ends are at or
2604close to the values of the smallest and largest integers.
2605
2606=item *
2607
2608C<binmode STDIN, ':raw'> could lead to segmentation faults on some platforms.
2609This has been fixed [RT #54828].
2610
2611=item *
2612
2613An off-by-one error meant that C<index $str, ...> was effectively being
2614executed as C<index "$str\0", ...>. This has been fixed [RT #53746].
2615
2616=item *
2617
2618Various leaks associated with named captures in regexes have been fixed
2619[RT #57024].
2620
2621=item *
2622
2623A weak reference to a hash would leak. This was affecting C<DBI>
2624[RT #56908].
2625
2626=item *
2627
2628Using (?|) in a regex could cause a segfault [RT #59734].
2629
2630=item *
2631
2632Use of a UTF-8 C<tr//> within a closure could cause a segfault [RT #61520].
2633
2634=item *
2635
2636Calling C<Perl_sv_chop()> or otherwise upgrading an SV could result in an
2637unaligned 64-bit access on the SPARC architecture [RT #60574].
2638
2639=item *
2640
2641In the 5.10.0 release, C<inc_version_list> would incorrectly list
2642C<5.10.*> after C<5.8.*>; this affected the C<@INC> search order
2643[RT #67628].
2644
2645=item *
2646
2647In 5.10.0, C<pack "a*", $tainted_value> returned a non-tainted value
2648[RT #52552].
2649
2650=item *
2651
2652In 5.10.0, C<printf> and C<sprintf> could produce the fatal error
2653C<panic: utf8_mg_pos_cache_update> when printing UTF-8 strings
2654[RT #62666].
2655
2656=item *
2657
2658In the 5.10.0 release, a dynamically created C<AUTOLOAD> method might be
2659missed (method cache issue) [RT #60220,60232].
2660
2661=item *
2662
2663In the 5.10.0 release, a combination of C<use feature> and C<//ee> could
2664cause a memory leak [RT #63110].
2665
2666=item *
2667
2668C<-C> on the shebang (C<#!>) line is once more permitted if it is also
2669specified on the command line. C<-C> on the shebang line used to be a
2670silent no-op I<if> it was not also on the command line, so perl 5.10.0
2671disallowed it, which broke some scripts. Now perl checks whether it is
2672also on the command line and only dies if it is not [RT #67880].
2673
2674=item *
2675
2676In 5.10.0, certain types of re-entrant regular expression could crash,
2677or cause the following assertion failure [RT #60508]:
2678
2679 Assertion rx->sublen >= (s - rx->subbeg) + i failed
2680
2681=item *
2682
7acb582f 2683Perl now includes previously missing files from the Unicode Character Database.
3ab3a109
JV
2684
2685=item *
2686
b6381718 2687Perl now honors C<TMPDIR> when opening an anonymous temporary file.
3ab3a109
JV
2688
2689=back
2690
b6381718 2691
3ab3a109
JV
2692=head1 Platform Specific Changes
2693
b6381718
JV
2694Perl is incredibly portable. In general, if a platform has a C compiler,
2695someone has ported Perl to it (or will soon). We're happy to announce
2696that Perl 5.12 includes support for several new platforms. At the same
2697time, it's time to bid farewell to some (very) old friends.
2698
3ab3a109
JV
2699=head2 New Platforms
2700
2701=over
2702
2703=item Haiku
2704
b6381718 2705Perl's developers have merged patches from Haiku's maintainers. Perl should now
3ab3a109
JV
2706build on Haiku.
2707
2708=item MirOS BSD
2709
2710Perl should now build on MirOS BSD.
2711
3ab3a109
JV
2712=back
2713
2714=head2 Discontinued Platforms
2715
2716=over
2717
3b72faae 2718=item Domain/OS
3ab3a109 2719
3ab3a109
JV
2720=item MiNT
2721
8ead3603
JD
2722=item Tenon MachTen
2723
3ab3a109
JV
2724=back
2725
2726=head2 Updated Platforms
2727
2728=over 4
2729
8ead3603
JD
2730=item AIX
2731
2732=over 4
2733
2734=item *
2735
2736Removed F<libbsd> for AIX 5L and 6.1. Only C<flock()> was used from F<libbsd>.
2737
2738=item *
2739
7b8c44fa
RT
2740Removed F<libgdbm> for AIX 5L and 6.1 if F<libgdbm> < 1.8.3-5 is installed.
2741The F<libgdbm> is delivered as an optional package with the AIX Toolbox.
2742Unfortunately the versions below 1.8.3-5 are broken.
8ead3603
JD
2743
2744=item *
2745
2746Hints changes mean that AIX 4.2 should work again.
2747
2748=back
2749
2750=item Cygwin
2751
2752=over 4
2753
2754=item *
2755
2756Perl now supports IPv6 on Cygwin 1.7 and newer.
2757
2758=item *
2759
2760On Cygwin we now strip the last number from the DLL. This has been the
2761behaviour in the cygwin.com build for years. The hints files have been
2762updated.
2763
2764=back
2765
3ab3a109
JV
2766=item Darwin (Mac OS X)
2767
2768=over 4
2769
2770=item *
2771
2772Skip testing the be_BY.CP1131 locale on Darwin 10 (Mac OS X 10.6),
2773as it's still buggy.
2774
2775=item *
2776
2777Correct infelicities in the regexp used to identify buggy locales
2778on Darwin 8 and 9 (Mac OS X 10.4 and 10.5, respectively).
2779
2780=back
2781
2782=item DragonFly BSD
2783
2784=over 4
2785
2786=item *
2787
2788Fix thread library selection [perl #69686]
2789
2790=back
2791
8ead3603 2792=item FreeBSD
3ab3a109
JV
2793
2794=over 4
2795
2796=item *
2797
8ead3603
JD
2798The hints files now identify the correct threading libraries on FreeBSD 7
2799and later.
3ab3a109 2800
8ead3603 2801=back
3ab3a109 2802
8ead3603 2803=item Irix
3ab3a109 2804
8ead3603 2805=over 4
3ab3a109
JV
2806
2807=item *
2808
8ead3603
JD
2809We now work around a bizarre preprocessor bug in the Irix 6.5 compiler:
2810C<cc -E -> unfortunately goes into K&R mode, but C<cc -E file.c> doesn't.
3ab3a109
JV
2811
2812=back
2813
8ead3603 2814=item NetBSD
3ab3a109
JV
2815
2816=over 4
2817
2818=item *
2819
8ead3603 2820Hints now supports versions 5.*.
3ab3a109
JV
2821
2822=back
2823
2824=item OpenVMS
2825
2826=over 4
2827
2828=item *
2829
b6381718 2830C<-UDEBUGGING> is now the default on VMS.
3ab3a109 2831
72d4e865 2832Like it has been everywhere else for ages and ages. Also make
3ab3a109
JV
2833command-line selection of -UDEBUGGING and -DDEBUGGING work in
2834configure.com; before the only way to turn it off was by saying
2835no in answer to the interactive question.
2836
2837=item *
2838
2839The default pipe buffer size on VMS has been updated to 8192 on 64-bit
2840systems.
2841
2842=item *
2843
2844Reads from the in-memory temporary files of C<PerlIO::scalar> used to fail
2845if C<$/> was set to a numeric reference (to indicate record-style reads).
2846This is now fixed.
2847
2848=item *
2849
2850VMS now supports C<getgrgid>.
2851
2852=item *
2853
2854Many improvements and cleanups have been made to the VMS file name handling
2855and conversion code.
2856
2857=item *
2858
2859Enabling the C<PERL_VMS_POSIX_EXIT> logical name now encodes a POSIX exit
2860status in a VMS condition value for better interaction with GNV's bash
72d4e865 2861shell and other utilities that depend on POSIX exit values. See
3ab3a109
JV
2862L<perlvms/"$?"> for details.
2863
2864=item *
2865
2866C<File::Copy> now detects Unix compatibility mode on VMS.
2867
2868=back
2869
8ead3603 2870=item Stratus VOS
3ab3a109 2871
8ead3603 2872=over 4
3ab3a109 2873
8ead3603 2874=item *
3ab3a109 2875
8ead3603 2876Various changes from Stratus have been merged in.
3ab3a109 2877
8ead3603 2878=back
3ab3a109 2879
8ead3603 2880=item Symbian
3ab3a109 2881
8ead3603 2882=over 4
3ab3a109 2883
8ead3603 2884=item *
3ab3a109 2885
8ead3603 2886There is now support for Symbian S60 3.2 SDK and S60 5.0 SDK.
3ab3a109 2887
8ead3603 2888=back
3ab3a109 2889
d13f8571 2890=item Windows
3ab3a109 2891
8ead3603 2892=over 4
3ab3a109 2893
8ead3603 2894=item *
3ab3a109 2895
d13f8571
JD
2896Perl 5.12 supports Windows 2000 and later. The supporting code for
2897legacy versions of Windows is still included, but will be removed
2898during the next development cycle.
3ab3a109 2899
8ead3603 2900=item *
3ab3a109 2901
d13f8571 2902Initial support for building Perl with MinGW-w64 is now available.
3ab3a109 2903
8ead3603
JD
2904=item *
2905
d13f8571 2906F<perl.exe> now includes a manifest resource to specify the C<trustInfo>
8ead3603 2907settings for Windows Vista and later. Without this setting Windows
d13f8571 2908would treat F<perl.exe> as a legacy application and apply various
8ead3603
JD
2909heuristics like redirecting access to protected file system areas
2910(like the "Program Files" folder) to the users "VirtualStore"
2911instead of generating a proper "permission denied" error.
2912
d13f8571
JD
2913The manifest resource also requests the Microsoft Common-Controls
2914version 6.0 (themed controls introduced in Windows XP). Check out the
2915Win32::VisualStyles module on CPAN to switch back to old style
2916unthemed controls for legacy applications.
2917
2918=item *
2919
2920The C<-t> filetest operator now only returns true if the filehandle
2921is connected to a console window. In previous versions of Perl it
2922would return true for all character mode devices, including F<NUL>
2923and F<LPT1>.
2924
2925=item *
2926
2927The C<-p> filetest operator now works correctly, and the
2928Fcntl::S_IFIFO constant is defined when Perl is compiled with
2929Microsoft Visual C. In previous Perl versions C<-p> always
2930returned a false value, and the Fcntl::S_IFIFO constant
2931was not defined.
2932
2933This bug is specific to Microsoft Visual C and never affected
2934Perl binaries built with MinGW.
2935
2936=item *
2937
2938The socket error codes are now more widely supported: The POSIX
2939module will define the symbolic names, like POSIX::EWOULDBLOCK,
2940and stringification of socket error codes in $! works as well
2941now;
2942
2943 C:\>perl -MPOSIX -E "$!=POSIX::EWOULDBLOCK; say $!"
2944 A non-blocking socket operation could not be completed immediately.
2945
2946=item *
2947
2948flock() will now set sensible error codes in $!. Previous Perl versions
2949copied the value of $^E into $!, which caused much confusion.
2950
2951=item *
2952
2953select() now supports all empty C<fd_set>s more correctly.
8ead3603 2954
d13f8571
JD
2955=item *
2956
2957C<'.\foo'> and C<'..\foo'> were treated differently than
2958C<'./foo'> and C<'../foo'> by C<do> and C<require> [RT #63492].
8ead3603
JD
2959
2960=item *
2961
2962Improved message window handling means that C<alarm> and C<kill> messages
2963will no longer be dropped under race conditions.
2964
d13f8571
JD
2965=item *
2966
2967Various bits of Perl's build infrastructure are no longer converted to
2968win32 line endings at release time. If this hurts you, please report the
2969problem with the L<perlbug> program included with perl.
2970
8ead3603 2971=back
3ab3a109
JV
2972
2973=back
2974
b6381718 2975
3ab3a109
JV
2976=head1 Known Problems
2977
2978This is a list of some significant unfixed bugs, which are regressions
72d4e865 2979from either 5.10.x or 5.8.x.
3ab3a109
JV
2980
2981=over 4
2982
2983=item *
2984
2985C<List::Util::first> misbehaves in the presence of a lexical C<$_>
2986(typically introduced by C<my $_> or implicitly by C<given>). The variable
2987which gets set for each iteration is the package variable C<$_>, not the
2988lexical C<$_> [RT #67694].
2989
2990A similar issue may occur in other modules that provide functions which
2991take a block as their first argument, like
2992
2993 foo { ... $_ ...} list
2994
2995=item *
2996
3ab3a109
JV
2997Some regexes may run much more slowly when run in a child thread compared
2998with the thread the pattern was compiled into [RT #55600].
2999
3000=item *
3001
3d3a8206
KW
3002Things like C<"\N{LATIN SMALL LIGATURE FF}" =~ /\N{LATIN SMALL LETTER F}+/>
3003will appear to hang as they get into a very long running loop [RT #72998].
3004
3005=item *
3006
d13f8571
JD
3007Several porters have reported mysterious crashes when Perl's entire
3008test suite is run after a build on certain Windows 2000 systems. When
3009run by hand, the individual tests reportedly work fine.
3ab3a109 3010
b6381718
JV
3011=back
3012
3013=head1 Errata
3014
3015=over
3016
3ab3a109
JV
3017=item *
3018
b6381718
JV
3019This one is actually a change introduced in 5.10.0, but it was missed
3020from that release's perldelta, so it is mentioned here instead.
3021
3022A bugfix related to the handling of the C</m> modifier and C<qr> resulted
3023in a change of behaviour between 5.8.x and 5.10.0:
3ab3a109 3024
b6381718
JV
3025 # matches in 5.8.x, doesn't match in 5.10.0
3026 $re = qr/^bar/; "foo\nbar" =~ /$re/m;
3ab3a109 3027
3ab3a109
JV
3028=back
3029
3030=head1 Acknowledgements
3031
3032Perl 5.12.0 represents approximately two years of development since
aac88411 3033Perl 5.10.0 and contains over 750,000 lines of changes across over
ee75e258 30343,000 files from over 200 authors and committers.
aac88411 3035
d13f8571
JD
3036Perl continues to flourish into its third decade thanks to a vibrant
3037community of users and developers. The following people are known to
3038have contributed the improvements that became Perl 5.12.0:
aac88411
JV
3039
3040Aaron Crane, Abe Timmerman, Abhijit Menon-Sen, Abigail, Adam Russell,
3041Adriano Ferreira, Ævar Arnfjörð Bjarmason, Alan Grover, Alexandr
3042Ciornii, Alex Davies, Alex Vandiver, Andreas Koenig, Andrew Rodland,
3043andrew@sundale.net, Andy Armstrong, Andy Dougherty, Jose AUGUSTE-ETIENNE,
3044Benjamin Smith, Ben Morrow, bharanee rathna, Bo Borgerson, Bo Lindbergh,
3045Brad Gilbert, Bram, Brendan O'Dea, brian d foy, Charles Bailey,
3046Chip Salzenberg, Chris 'BinGOs' Williams, Christoph Lamprecht, Chris
3047Williams, chromatic, Claes Jakobsson, Craig A. Berry, Dan Dascalescu,
3048Daniel Frederick Crisman, Daniel M. Quinlan, Dan Jacobson, Dan Kogai,
3049Dave Mitchell, Dave Rolsky, David Cantrell, David Dick, David Golden,
3050David Mitchell, David M. Syzdek, David Nicol, David Wheeler, Dennis
3051Kaarsemaker, Dintelmann, Peter, Dominic Dunlop, Dr.Ruud, Duke Leto,
3052Enrico Sorcinelli, Eric Brine, Father Chrysostomos, Florian Ragwitz,
3053Frank Wiegand, Gabor Szabo, Gene Sullivan, Geoffrey T. Dairiki, George
3054Greer, Gerard Goossen, Gisle Aas, Goro Fuji, Graham Barr, Green, Paul,
3055Hans Dieter Pearcey, Harmen, H. Merijn Brand, Hugo van der Sanden,
3056Ian Goodacre, Igor Sutton, Ingo Weinhold, James Bence, James Mastros,
3057Jan Dubois, Jari Aalto, Jarkko Hietaniemi, Jay Hannah, Jerry Hedden,
3058Jesse Vincent, Jim Cromie, Jody Belka, John E. Malmberg, John Malmberg,
3059John Peacock, John Peacock via RT, John P. Linderman, John Wright,
3060Josh ben Jore, Jos I. Boumans, Karl Williamson, Kenichi Ishigaki, Ken
3061Williams, Kevin Brintnall, Kevin Ryde, Kurt Starsinic, Leon Brocard,
3062Lubomir Rintel, Luke Ross, Marcel Grünauer, Marcus Holland-Moritz, Mark
3063Jason Dominus, Marko Asplund, Martin Hasch, Mashrab Kuvatov, Matt Kraai,
3064Matt S Trout, Max Maischein, Michael Breen, Michael Cartmell, Michael
3065G Schwern, Michael Witten, Mike Giroux, Milosz Tanski, Moritz Lenz,
3066Nicholas Clark, Nick Cleaton, Niko Tyni, Offer Kaye, Osvaldo Villalon,
3067Paul Fenwick, Paul Gaborit, Paul Green, Paul Johnson, Paul Marquess,
3068Philip Hazel, Philippe Bruhat, Rafael Garcia-Suarez, Rainer Tammer,
3069Rajesh Mandalemula, Reini Urban, Renée Bäcker, Ricardo Signes,
3070Ricardo SIGNES, Richard Foley, Rich Rauenzahn, Rick Delaney, Risto
3071Kankkunen, Robert May, Roberto C. Sanchez, Robin Barker, SADAHIRO
3072Tomoyuki, Salvador Ortiz Garcia, Sam Vilain, Scott Lanning, Sébastien
3073Aperghis-Tramoni, Sérgio Durigan Júnior, Shlomi Fish, Simon 'corecode'
3074Schubert, Sisyphus, Slaven Rezic, Smylers, Steffen Müller, Steffen
3075Ullrich, Stepan Kasal, Steve Hay, Steven Schubiger, Steve Peters, Tels,
3076The Doctor, Tim Bunce, Tim Jenness, Todd Rinaldo, Tom Christiansen,
3077Tom Hukins, Tom Wyant, Tony Cook, Torsten Schoenfeld, Tye McQueen,
3078Vadim Konovalov, Vincent Pit, Hio YAMASHINA, Yasuhiro Matsumoto,
3079Yitzchak Scott-Thoennes, Yuval Kogman, Yves Orton, Zefram, Zsban Ambrus
3080
3081This is woefully incomplete as it's automatically generated from version
3082control history. In particular, it doesn't include the names of the
3083(very much appreciated) contributors who reported issues in previous
3084versions of Perl that helped make Perl 5.12.0 better. For a more complete
3085list of all of Perl's historical contributors, please see the C<AUTHORS>
3086file in the Perl 5.12.0 distribution.
3ab3a109
JV
3087
3088Many of the changes included in this version originated in the CPAN
3089modules included in Perl's core. We're grateful to the entire CPAN
3090community for helping Perl to flourish.
3091
3092=head1 Reporting Bugs
3093
3094If you find what you think is a bug, you might check the articles
3095recently posted to the comp.lang.perl.misc newsgroup and the perl
72d4e865 3096bug database at L<http://rt.perl.org/perlbug/>. There may also be
3ab3a109
JV
3097information at L<http://www.perl.org/>, the Perl Home Page.
3098
3099If you believe you have an unreported bug, please run the B<perlbug>
72d4e865
JV
3100program included with your release. Be sure to trim your bug down
3101to a tiny but sufficient test case. Your bug report, along with the
3ab3a109
JV
3102output of C<perl -V>, will be sent off to perlbug@perl.org to be
3103analyzed by the Perl porting team.
3104
3105If the bug you are reporting has security implications, which make it
3106inappropriate to send to a publicly archived mailing list, then please send
3107it to perl5-security-report@perl.org. This points to a closed subscription
3108unarchived mailing list, which includes all the core committers, who be able
3109to help assess the impact of issues, figure out a resolution, and help
3110co-ordinate the release of patches to mitigate or fix the problem across all
3111platforms on which Perl is supported. Please only use this address for
3112security issues in the Perl core, not for modules independently
3113distributed on CPAN.
3114
3115=head1 SEE ALSO
3116
3117The F<Changes> file for an explanation of how to view exhaustive details
3118on what changed.
3119
3120The F<INSTALL> file for how to build Perl.
3121
3122The F<README> file for general stuff.
3123
3124The F<Artistic> and F<Copying> files for copyright information.
3125
3126=cut