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1=head1 NAME
2
3perl5120delta - what is new for perl v5.12.0
4
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5=head1 XXX - THIS DOCUMENT IS ONLY CURRENT THROUGH PERL5114
6
dac9950b 7FIX ME BEFORE RELEASE
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8
9OTHER ISSUES:
10
11UPDATED MODULE LIST NEEDS TO BE GENERATED
12ORDERING NEEDS CHECKING
13HEAVY COPYEDITING IS NEEDED
14
15
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16=head1 DESCRIPTION
17
18This document describes differences between the 5.10.0 release and
19the 5.12.0 release.
20
21Many of the bug fixes in 5.12.0 were already seen in the 5.10.1
22maintenance release since the two releases were kept closely
23coordinated (while 5.12.0 was still called 5.11.something).
24
25You can see the list of changes in the 5.10.1 release
26by reading L<perl5101delta>.
27
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28=head1 Core Enhancements
29
30=head2 qr overloading
31
32It is now possible to overload the C<qr//> operator, that is,
33conversion to regexp, like it was already possible to overload
34conversion to boolean, string or number of objects. It is invoked when
c66407fa 35an object appears on the right hand side of the C<=~> operator or when
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36it is interpolated into a regexp. See L<overload>.
37
38=head2 Pluggable keywords
39
40Extension modules can now cleanly hook into the Perl parser to define
41new kinds of keyword-headed expression and compound statement. The
42syntax following the keyword is defined entirely by the extension. This
43allow a completely non-Perl sublanguage to be parsed inline, with the
c66407fa 44correct ops cleanly generated. This feature is currently considered
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45experimental.
46
47See L<perlapi/PL_keyword_plugin> for the mechanism. The Perl core
48source distribution also includes a new module
49L<XS::APItest::KeywordRPN>, which implements reverse Polish notation
50arithmetic via pluggable keywords. This module is mainly used for test
51purposes, and is not normally installed, but also serves as an example
52of how to use the new mechanism.
53
54=head2 APIs for more internals
55
56The lowest layers of the lexer and parts of the pad system now have C
57APIs available to XS extensions. These are necessary to support proper
58use of pluggable keywords, but have other uses too. The new APIs are
59experimental, and only cover a small proportion of what would be
60necessary to take full advantage of the core's facilities in these
61areas. It is intended that the Perl 5.13 development cycle will see the
62addition of a full range of clean, supported interfaces.
63
64=head2 Overridable function lookup
65
66Where an extension module hooks the creation of rv2cv ops to modify the
67subroutine lookup process, this now works correctly for bareword
68subroutine calls. This means that prototypes on subroutines referenced
69this way will be processed correctly. (Previously bareword subroutine
70names were initially looked up, for parsing purposes, by an unhookable
71mechanism, so extensions could only properly influence subroutine names
72that appeared with an C<&> sigil.)
73
74=head2 Unicode version
75
76Perl is shipped with the latest Unicode version, 5.2, dated October 2009. See
77L<http://www.unicode.org/versions/Unicode5.2.0> for details about this release
78of Unicode. See L<perlunicode> for instructions on installing and using
79older versions of Unicode.
80
81=head2 Unicode properties
82
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83A concerted effort has been made to update Perl to be in sync with the latest
84Unicode standard. Changes for this include:
85
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86Perl can now handle every Unicode character property. A new pod,
87L<perluniprops>, lists all available non-Unihan character properties. By
88default the Unihan properties and certain others (deprecated and Unicode
89internal-only ones) are not exposed. See below for more details on
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90these; there is also a section in the pod listing them, and explaining
91why they are not exposed.
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92
93Perl now fully supports the Unicode compound-style of using C<=> and C<:>
94in writing regular expressions: C<\p{property=value}> and
95C<\p{property:value}> (both of which mean the same thing).
96
97Perl now fully supports the Unicode loose matching rules for text
c66407fa 98between the braces in C<\p{...}> constructs. In addition, Perl allows
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99underscores between digits of numbers.
100
101All the Unicode-defined synonyms for properties and property values are
102now accepted.
103
104C<qr/\X/>, which matches a Unicode logical character, has been expanded to work
b21d8e53 105better with various Asian languages. It now is defined as an I<extended
3ab3a109 106grapheme cluster>. (See L<http://www.unicode.org/reports/tr29/>).
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107Anything matched previously and that made sense will continue to be
108matched, but in addition:
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109
110=over
111
112=item *
113
b21d8e53 114C<\X> will not break apart a C<S<CR LF>> sequence.
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115
116=item *
117
b21d8e53 118C<\X> will now match a sequence which includes the C<ZWJ> and C<ZWNJ> characters.
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119
120=item *
121
122C<\X> will now always match at least one character, including an initial mark.
123Marks generally come after a base character, but it is possible in Unicode to
124have them in isolation, and C<\X> will now handle that case, for example at the
b21d8e53 125beginning of a line, or after a C<ZWSP>. And this is the part where C<\X>
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126doesn't match the things that it used to that don't make sense. Formerly, for
127example, you could have the nonsensical case of an accented LF.
128
129=item *
130
131C<\X> will now match a (Korean) Hangul syllable sequence, and the Thai and Lao
132exception cases.
133
134=back
135
136Otherwise, this change should be transparent for the non-affected languages.
137
138C<\p{...}> matches using the Canonical_Combining_Class property were
139completely broken in previous Perls. This is now fixed.
140
141In previous Perls, the Unicode C<Decomposition_Type=Compat> property and a
142Perl extension had the same name, which led to neither matching all the
143correct values (with more than 100 mistakes in one, and several thousand
144in the other). The Perl extension has now been renamed to be
145C<Decomposition_Type=Noncanonical> (short: C<dt=noncanon>). It has the same
146meaning as was previously intended, namely the union of all the
147non-canonical Decomposition types, with Unicode C<Compat> being just one of
148those.
149
150C<\p{Uppercase}> and C<\p{Lowercase}> have been brought into line with the
151Unicode definitions. This means they each match a few more characters
152than previously.
153
154C<\p{Cntrl}> now matches the same characters as C<\p{Control}>. This means it
155no longer will match Private Use (gc=co), Surrogates (gc=cs), nor Format
156(gc=cf) code points. The Format code points represent the biggest
157possible problem. All but 36 of them are either officially deprecated
158or strongly discouraged from being used. Of those 36, likely the most
159widely used are the soft hyphen (U+00AD), and BOM, ZWSP, ZWNJ, WJ, and
b21d8e53 160similar characters, plus bidirectional controls.
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161
162C<\p{Alpha}> now matches the same characters as C<\p{Alphabetic}>. The Perl
163definition included a number of things that aren't really alpha (all
164marks), while omitting many that were. As a direct consequence, the
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165definitions of C<\p{Alnum}> and C<\p{Word}> which depend on Alpha also change
166correspondingly.
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167
168C<\p{Word}> also now doesn't match certain characters it wasn't supposed
169to, such as fractions.
170
171C<\p{Print}> no longer matches the line control characters: Tab, LF, CR,
b21d8e53 172FF, VT, and NEL. This brings it in line with standards and the documentation.
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173
174C<\p{Decomposition_Type=Canonical}> now includes the Hangul syllables.
175
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176C<\p{XDigit}> now matches the same characters as C<\p{Hex_Digit}>. This
177means that in addition to the characters it currently matches,
178C<[A-Fa-f0-9]>, it will also match the 22 fullwidth equivalents, for
179example U+FF10: FULLWIDTH DIGIT ZERO.
180
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181The Numeric type property has been extended to include the Unihan
182characters.
183
184There is a new Perl extension, the 'Present_In', or simply 'In',
185property. This is an extension of the Unicode Age property, but
186C<\p{In=5.0}> matches any code point whose usage has been determined
187I<as of> Unicode version 5.0. The C<\p{Age=5.0}> only matches code points
188added in I<precisely> version 5.0.
189
190A number of properties did not have the correct values for unassigned
191code points. This is now fixed. The affected properties are
192Bidi_Class, East_Asian_Width, Joining_Type, Decomposition_Type,
193Hangul_Syllable_Type, Numeric_Type, and Line_Break.
194
195The Default_Ignorable_Code_Point, ID_Continue, and ID_Start properties
196have been updated to their current Unicode definitions.
197
198Certain properties that are supposed to be Unicode internal-only were
199erroneously exposed by previous Perls. Use of these in regular
200expressions will now generate, if enabled, a deprecated warning message.
201The properties are: Other_Alphabetic, Other_Default_Ignorable_Code_Point,
202Other_Grapheme_Extend, Other_ID_Continue, Other_ID_Start, Other_Lowercase,
203Other_Math, and Other_Uppercase.
204
205An installation can now fairly easily change which Unicode properties
206Perl understands. As mentioned above, certain properties are by default
207turned off. These include all the Unihan properties (which should be
208accessible via the CPAN module Unicode::Unihan) and any deprecated or
209Unicode internal-only property that Perl has never exposed.
210
211The generated files in the C<lib/unicore/To> directory are now more
212clearly marked as being stable, directly usable by applications.
213New hash entries in them give the format of the normal entries,
214which allows for easier machine parsing. Perl can generate files
215in this directory for any property, though most are suppressed. An
216installation can choose to change which get written. Instructions
217are in L<perluniprops>.
218
219=head2 Regular Expressions
220
221U+0FFFF is now a legal character in regular expressions.
222
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223=head2 A proper interface for pluggable Method Resolution Orders
224
225As of Perl 5.11.0 there is a new interface for plugging and using method
226resolution orders other than the default (linear depth first search).
227The C3 method resolution order added in 5.10.0 has been re-implemented as
228a plugin, without changing its Perl-space interface. See L<perlmroapi> for
229more information.
230
231=head2 The C<overloading> pragma
232
233This pragma allows you to lexically disable or enable overloading
234for some or all operations. (Yuval Kogman)
235
b3b85878 236=head2 C<\N> experimental regex escape
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237
238A new regex escape has been added, C<\N>. It will match any character that
239is not a newline, independently from the presence or absence of the single
ff3f963a 240line match modifier C</s>. It is not usable within a character class.
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241C<\N{3}> means to match 3 non-newlines; C<\N{5,}> means to match at least 5.
242C<\N{NAME}> still means the character or sequence named C<NAME>, but C<NAME> no
243longer can be things like C<3>, or C<5,>.
244Compatibility with Unicode names is preserved, as none look like these, but it
245has been possible to create custom names that do look like them, and those will
246no longer work. (Rafael Garcia-Suarez)
3ab3a109 247
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248This will break a L<custom charnames translator|charnames/CUSTOM TRANSLATORS>
249which allows numbers for character names, as C<\N{3}> will now mean to match 3
250non-newline characters, and not the character whose name is C<3>. (No standard
251name is a number, so only a custom translator would be affected.)
252
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253This escape is experimental, subject to change, because there is some concern
254about possible confusion with the previous meaning of C<\N{...}>
255
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256=head2 \N{...} now compiles better, always forces UTF-8 internal representation.
257
258There were several problems that have been fixed with recognizing C<\N{...}>
259constructs. As part of this, any scalar or regex that has either a
260C<\N{I<name>}> or C<\N{U+I<wide hex char>}> in its definition will be stored in
261UTF-8 format. (This was true previously for all occurences of C<\N{I<name>}>
262that did not use a custom translator, but now it's always true.)
263
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264=head2 Implicit strictures
265
266Using the C<use VERSION> syntax with a version number greater or equal
267to 5.11.0 will also lexically enable strictures just like C<use strict>
268would do (in addition to enabling features.) So, the following:
269
270 use 5.11.0;
271
272will now imply:
273
274 use strict;
275 use feature ':5.11';
276
277=head2 Parallel tests
278
279The core distribution can now run its regression tests in parallel on
280Unix-like platforms. Instead of running C<make test>, set C<TEST_JOBS> in
281your environment to the number of tests to run in parallel, and run
282C<make test_harness>. On a Bourne-like shell, this can be done as
283
284 TEST_JOBS=3 make test_harness # Run 3 tests in parallel
285
286An environment variable is used, rather than parallel make itself, because
287L<TAP::Harness> needs to be able to schedule individual non-conflicting test
288scripts itself, and there is no standard interface to C<make> utilities to
289interact with their job schedulers.
290
291Note that currently some test scripts may fail when run in parallel (most
292notably C<ext/IO/t/io_dir.t>). If necessary run just the failing scripts
293again sequentially and see if the failures go away.
294
295=head2 The C<...> operator
296
297A new operator, C<...>, nicknamed the Yada Yada operator, has been added.
c66407fa 298It is intended to mark placeholder code that is not yet implemented.
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299See L<perlop/"Yada Yada Operator">. (chromatic)
300
301=head2 DTrace support
302
303Some support for DTrace has been added. See "DTrace support" in F<INSTALL>.
304
305=head2 Support for C<configure_requires> in CPAN module metadata
306
307Both C<CPAN> and C<CPANPLUS> now support the C<configure_requires> keyword
308in the F<META.yml> metadata file included in most recent CPAN distributions.
309This allows distribution authors to specify configuration prerequisites that
310must be installed before running F<Makefile.PL> or F<Build.PL>.
311
312See the documentation for C<ExtUtils::MakeMaker> or C<Module::Build> for more
313on how to specify C<configure_requires> when creating a distribution for CPAN.
314
315=head2 C<each> is now more flexible
316
317The C<each> function can now operate on arrays.
318
319=head2 Y2038 compliance
320
321Perl's core time-related functions are now Y2038 compliant. (With 29
322years to spare!)
323
324=head2 C<$,> flexibility
325
326The variable C<$,> may now be tied.
327
328=head2 // in where clauses
329
330// now behaves like || in when clauses
331
332=head2 Enabling warnings from your shell environment
333
334You can now set C<-W> from the C<PERL5OPT> environment variable
335
336=head2 C<delete local>
337
338C<delete local> now allows you to locally delete a hash entry.
339
340=head2 New support for Abstract namespace sockets
341
342Abstract namespace sockets are Linux-specific socket type that live in
343AF_UNIX family, slightly abusing it to be able to use arbitrary
344character arrays as addresses: They start with nul byte and are not
345terminated by nul byte, but with the length passed to the socket()
346system call.
347
252eec4f 348=head2 New C<package NAME VERSION> syntax
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349
350This new syntax allows a module author to set the $VERSION of a namespace
351when the namespace is declared with 'package'. It eliminates the need
352for C<our $VERSION = ...> and similar constructs. E.g.
353
354 package Foo::Bar 1.23;
355 # $Foo::Bar::VERSION == 1.23
356
357There are several advantages to this:
358
359=over
360
361=item *
362
252eec4f 363C<$VERSION> is parsed in exactly the same way as C<use NAME VERSION>
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364
365=item *
366
367C<$VERSION> is set at compile time
368
369=item *
370
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371C<$VERSION> is a version object that provides proper overloading of
372comparision operators so comparing C<$VERSION> to decimal (1.23) or
373dotted-decimal (v1.2.3) version numbers works correctly.
374
375=item *
376
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377Eliminates C<$VERSION = ...> and C<eval $VERSION> clutter
378
379=item *
380
381As it requires VERSION to be a numeric literal or v-string
382literal, it can be statically parsed by toolchain modules
383without C<eval> the way MM-E<gt>parse_version does for C<$VERSION = ...>
384
385=item *
386
3ab3a109 387It does not break old code with only C<package NAME>, but code that uses
252eec4f 388C<package NAME VERSION> will need to be restricted to perl 5.12.0 or newer
3ab3a109 389This is analogous to the change to C<open> from two-args to three-args.
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390Users requiring the latest Perl will benefit, and perhaps after several
391years, it will become a standard practice.
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392
393=back
394
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395However, C<package NAME VERSION> requires a new, 'strict' version
396number format. See L<"Version number formats"> for details.
397
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398=head1 Incompatible Changes
399
400=head2 Version number formats
401
402Acceptable version number formats have been formalized into "strict" and
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403"lax" rules. C<package NAME VERSION> takes a strict version number.
404C<UNIVERSAL::VERSION> and the L<version> object constructors take lax
405version numbers. Providing an invalid version will result in a fatal
406error. The version argument in C<use NAME VERSION> is first parsed as a
407numeric literal or v-string and then passed to C<UNIVERSAL::VERSION>
408(and must then pass the "lax" format test).
409
410These formats are documented fully in the L<version> module. To a first
411approximation, a "strict" version number is a positive decimal number
412(integer or decimal-fraction) without exponentiation or else a
413dotted-decimal v-string with a leading 'v' character and at least three
414components. A "lax" version number allows v-strings with fewer than
415three components or without a leading 'v'. Under "lax" rules, both
416decimal and dotted-decimal versions may have a trailing "alpha"
417component separated by an underscore character after a fractional or
418dotted-decimal component.
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419
420The L<version> module adds C<version::is_strict> and C<version::is_lax>
421functions to check a scalar against these rules.
422
c66407fa 423=head2 @INC reorganization
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424
425In @INC, ARCHLIB and PRIVLIB now occur after after the current version's
426site_perl and vendor_perl.
427
428=head2 Switch statement changes
429
430The handling of complex expressions by the C<given>/C<when> switch
431statement has been enhanced. These enhancements are also available in
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4325.10.1 and subsequent 5.10 releases. There are two new cases where
433C<when> now interprets its argument as a boolean, instead of an
434expression to be used in a smart match:
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435
436=head2 flip-flop operators
437
438The C<..> and C<...> flip-flop operators are now evaluated in boolean
439context, following their usual semantics; see L<perlop/"Range Operators">.
440
441Note that, as in perl 5.10.0, C<when (1..10)> will not work to test
442whether a given value is an integer between 1 and 10; you should use
443C<when ([1..10])> instead (note the array reference).
444
445However, contrary to 5.10.0, evaluating the flip-flop operators in boolean
446context ensures it can now be useful in a C<when()>, notably for
447implementing bistable conditions, like in:
448
449 when (/^=begin/ .. /^=end/) {
450 # do something
451 }
452
453=head2 defined-or operator
454
455A compound expression involving the defined-or operator, as in
456C<when (expr1 // expr2)>, will be treated as boolean if the first
457expression is boolean. (This just extends the existing rule that applies
458to the regular or operator, as in C<when (expr1 || expr2)>.)
459
460=head2 Smart match changes
461
462This section details more changes brought to the semantics to
463the smart match operator, that naturally also modify the behaviour
464of the switch statements where smart matching is implicitly used.
c66407fa 465These changes were also made for the 5.10.1 release, and will remain in
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466subsequent 5.10 releases.
467
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468=head3 Changes to type-based dispatch
469
470The smart match operator C<~~> is no longer commutative. The behaviour of
471a smart match now depends primarily on the type of its right hand
472argument. Moreover, its semantics have been adjusted for greater
473consistency or usefulness in several cases. While the general backwards
474compatibility is maintained, several changes must be noted:
475
476=over 4
477
478=item *
479
480Code references with an empty prototype are no longer treated specially.
481They are passed an argument like the other code references (even if they
482choose to ignore it).
483
484=item *
485
486C<%hash ~~ sub {}> and C<@array ~~ sub {}> now test that the subroutine
487returns a true value for each key of the hash (or element of the
488array), instead of passing the whole hash or array as a reference to
489the subroutine.
490
491=item *
492
493Due to the commutativity breakage, code references are no longer
494treated specially when appearing on the left of the C<~~> operator,
495but like any vulgar scalar.
496
497=item *
498
499C<undef ~~ %hash> is always false (since C<undef> can't be a key in a
500hash). No implicit conversion to C<""> is done (as was the case in perl
5015.10.0).
502
503=item *
504
505C<$scalar ~~ @array> now always distributes the smart match across the
506elements of the array. It's true if one element in @array verifies
507C<$scalar ~~ $element>. This is a generalization of the old behaviour
508that tested whether the array contained the scalar.
509
510=back
511
512The full dispatch table for the smart match operator is given in
513L<perlsyn/"Smart matching in detail">.
514
515=head3 Smart match and overloading
516
517According to the rule of dispatch based on the rightmost argument type,
518when an object overloading C<~~> appears on the right side of the
519operator, the overload routine will always be called (with a 3rd argument
520set to a true value, see L<overload>.) However, when the object will
521appear on the left, the overload routine will be called only when the
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522rightmost argument is a simple scalar. This way, distributivity of smart
523match across arrays is not broken, as well as the other behaviours with
524complex types (coderefs, hashes, regexes). Thus, writers of overloading
525routines for smart match mostly need to worry only with comparing
526against a scalar, and possibly with stringification overloading; the
527other common cases will be automatically handled consistently.
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528
529C<~~> will now refuse to work on objects that do not overload it (in order
530to avoid relying on the object's underlying structure). (However, if the
531object overloads the stringification or the numification operators, and
532if overload fallback is active, it will be used instead, as usual.)
533
534=head2 Labels can't be keywords
535
536Labels used as targets for the C<goto>, C<last>, C<next> or C<redo>
537statements cannot be keywords anymore. This restriction will prevent
538potential confusion between the C<goto LABEL> and C<goto EXPR> syntaxes:
539for example, a statement like C<goto print> would jump to a label whose
540name would be the return value of C<print()>, (usually 1), instead of a
541label named C<print>. Moreover, the other control flow statements
542would just ignore any keyword passed to them as a label name. Since
543such labels cannot be defined anymore, this kind of error will be
544avoided.
545
546=head2 Other incompatible changes
547
548=over 4
549
550=item *
551
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552The definitions of a number of Unicode properties have changed to match those
553of the current Unicode standard. These are listed above under L</Unicode
adbcfde0 554properties>. This could break code that is expecting the old definitions.
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555
556=item *
557
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558The boolkeys op moved to the group of hash ops. This breaks binary
559compatibility.
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560
561=item *
562
563Filehandles are blessed directly into C<IO::Handle>, as C<FileHandle> is
564merely a wrapper around C<IO::Handle>.
565
566The previous behaviour was to bless Filehandles into L<FileHandle>
567(an empty proxy class) if it was loaded into memory and otherwise
568to bless them into C<IO::Handle>.
569
570=item *
571
572The semantics of C<use feature :5.10*> have changed slightly.
573See L<"Modules and Pragmata"> for more information.
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574
575=item *
576
577The version control system used for the development of the perl
578interpreter has been switched from Perforce to git. This is mainly an
579internal issue that only affects people actively working on the perl core;
580but it may have minor external visibility, for example in some of details
581of the output of C<perl -V>. See L<perlrepository> for more information.
582
583=item *
584
585The internal structure of the C<ext/> directory in the perl source has
586been reorganised. In general, a module C<Foo::Bar> whose source was
587stored under F<ext/Foo/Bar/> is now located under F<ext/Foo-Bar/>. Also,
588nearly all dual-life modules have been moved from F<lib/> to F<ext/>. This
589is purely a source tarball change, and should make no difference to the
590compilation or installation of perl, unless you have a very customised build
591process that explicitly relies on this structure, or which hard-codes the
592C<nonxs_ext> F<Configure> parameter. Specifically, this change does not by
593default alter the location of any files in the final installation.
594
595=item *
596
597As part of the C<Test::Harness> 2.x to 3.x upgrade, the experimental
598C<Test::Harness::Straps> module has been removed.
599See L</"Updated Modules"> for more details.
600
601=item *
602
603As part of the C<ExtUtils::MakeMaker> upgrade, the
604C<ExtUtils::MakeMaker::bytes> and C<ExtUtils::MakeMaker::vmsish> modules
605have been removed from this distribution.
606
607=item *
608
609C<Module::CoreList> no longer contains the C<%:patchlevel> hash.
610
611=item *
612
613This one is actually a change introduced in 5.10.0, but it was missed
614from that release's perldelta, so it is mentioned here instead.
615
616A bugfix related to the handling of the C</m> modifier and C<qr> resulted
617in a change of behaviour between 5.8.x and 5.10.0:
618
619 # matches in 5.8.x, doesn't match in 5.10.0
620 $re = qr/^bar/; "foo\nbar" =~ /$re/m;
621
622=item *
623
624C<length undef> now returns undef.
625
626=item *
627
628Unsupported private C API functions are now declared "static" to prevent
629leakage to Perl's public API.
630
631=item *
632
633To support the bootstrapping process, F<miniperl> no longer builds with
634UTF-8 support in the regexp engine.
635
636This allows a build to complete with PERL_UNICODE set and a UTF-8 locale.
637Without this there's a bootstrapping problem, as miniperl can't load the UTF-8
638components of the regexp engine, because they're not yet built.
639
640=item *
641
c66407fa
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642F<miniperl>'s @INC is now restricted to just C<-I...>, the split of
643C<$ENV{PERL5LIB}>, and "C<.>"
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644
645=item *
646
647A space or a newline is now required after a C<"#line XXX"> directive.
648
649=item *
650
651Tied filehandles now have an additional method EOF which provides the EOF type
652
653=item *
654
c66407fa
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655To better match all other flow control statements, C<foreach> may no
656longer be used as an attribute.
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657
658=back
659
660=head1 Deprecations
661
662From time to time, Perl's developers find it necessary to deprecate
663features or modules we've previously shipped as part of the core
664distribution. We are well aware of the pain and frustration that a
665backwards-incompatible change to Perl can cause for developers building
666or maintaining software in Perl. You can be sure that when we deprecate
667a functionality or syntax, it isn't a choice we make lightly. Sometimes,
668we choose to deprecate functionality or syntax because it was found to
669be poorly designed or implemented. Sometimes, this is because they're
670holding back other features or causing performance problems. Sometimes,
671the reasons are more complex. Wherever possible, we try to keep deprecated
672functionality available to developers in its previous form for at least
673one major release. So long as a deprecated feature isn't actively
674disrupting our ability to maintain and extend Perl, we'll try to leave
675it in place as long as possible.
676
677The following items are now deprecated.
678
679=over 4
680
681=item Use of C<:=> to mean an empty attribute list is now deprecated.
682
683An accident of Perl's parser meant that these constructions were all
684equivalent:
685
686 my $pi := 4;
687 my $pi : = 4;
688 my $pi : = 4;
689
690with the C<:> being treated as the start of an attribute list, which
691ends before the C<=>. As whitespace is not significant here, all are
692parsed as an empty attribute list, hence all the above are equivalent
693to, and better written as
694
695 my $pi = 4;
696
697because no attribute processing is done for an empty list.
698
699As is, this meant that C<:=> cannot be used as a new token, without
700silently changing the meaning of existing code. Hence that particular
701form is now deprecated, and will become a syntax error. If it is
702absolutely necessary to have empty attribute lists (for example,
703because of a code generator) then avoid the warning by adding a space
704before the C<=>.
705
c66407fa 706=item C<< UNIVERSAL->import() >>
3ab3a109 707
c66407fa 708The method C<< UNIVERSAL->import() >> is now deprecated. Attempting to
3ab3a109 709pass import arguments to a C<use UNIVERSAL> statement will result in a
c66407fa 710deprecation warning.
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711
712=item Use of "goto" to jump into a construct is deprecated
713
c66407fa
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714Using C<goto> to jump from an outer scope into an inner scope is now
715deprecated. This rare use case was causing problems in the
716implementation of scopes.
3ab3a109 717
8c66a230
KW
718=item Custom character names in \N{name} should look like names
719
720In C<\N{I<name>}>, I<name> can be just about anything. The standard Unicode
721names have a very limited domain, but a custom name translator could create
722names that are, for example, made up entirely of punctuation symbols. It is
723now deprecated to make names that don't begin with an alphabetic character, and
724aren't alphanumeric or contain other than a very few other characters,
725namely spaces, dashes, parentheses and colons. Because of the added meaning of
726C<\N> (See L</C<\N> experimental regex escape>), names that look like curly
727brace -enclosed quantifiers won't work. For example, C<\N{3,4}> now means to
728match 3 to 4 non-newlines; before a custom name C<3,4> could have been created.
729
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730=item Deprecated Modules
731
732The following modules will be removed from the core distribution in a future
733release, and should be installed from CPAN instead. Distributions on CPAN
734which require these should add them to their prerequisites. The core versions
735of these modules warnings will issue a deprecation warning.
736
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737If you ship a packaged version of Perl, either alone or as part of a larger
738system, then you should carefully consider the reprecussions of core module
739deprecations. You may want to consider shipping your default build of
740Perl with packages for some or all deprecated modules which install into
741C<vendor> or C<site> perl library directories. This will inhibit the
742deprecation warnings.
743
744Alternatively, you may want to consider patching F<lib/deprecate.pm>
745to provide deprecation warnings specific to your packaging system or
b951c6bd
NC
746distribution of Perl, consistent with how your packaging system or
747distribution manages a staged transition from a release where the
748installation of a single package provides the given functionality, to a later
749release where the system administrator needs to know to install multiple
750packages to get that same functionality.
8df7d2a3 751
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752=over
753
c66407fa
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754=item L<Class::ISA>
755
756=item L<Pod::Plainer>
757
758=item L<Shell>
3ab3a109 759
c66407fa 760=item L<Switch>
3ab3a109 761
c66407fa
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762Switch is buggy and should be avoided. See L<perlsyn/"Switch
763statements"> for its replacement.
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764
765=back
766
767=item suidperl
768
769C<suidperl> has been removed. It used to provide a mechanism to
770emulate setuid permission bits on systems that don't support it properly.
771
772=item Assignment to $[
773
774=item attrs
775
776Remove attrs, which has been deprecated since 1999-10-02.
777
778=item Use of the attribute :locked on subroutines.
779
780=item Use of "locked" with the attributes pragma.
781
782=item Use of "unique" with the attributes pragma.
783
784=item Numerous Perl 4-era libraries:
785
786F<termcap.pl>, F<tainted.pl>, F<stat.pl>, F<shellwords.pl>, F<pwd.pl>,
787F<open3.pl>, F<open2.pl>, F<newgetopt.pl>, F<look.pl>, F<find.pl>,
788F<finddepth.pl>, F<importenv.pl>, F<hostname.pl>, F<getopts.pl>,
789F<getopt.pl>, F<getcwd.pl>, F<flush.pl>, F<fastcwd.pl>, F<exceptions.pl>,
790F<ctime.pl>, F<complete.pl>, F<cacheout.pl>, F<bigrat.pl>, F<bigint.pl>,
791F<bigfloat.pl>, F<assert.pl>, F<abbrev.pl>, F<dotsh.pl>, and
792F<timelocal.pl> are all now deprecated. Using them will incur a warning.
793
794=back
795
796=head1 Modules and Pragmata
797
798=head2 Dual-lifed modules moved
799
800Dual-lifed modules maintained primarily in the Perl core now live in dist/.
801Dual-lifed modules maintained primarily on CPAN now live in cpan/
802
803In previous releases of Perl, it was customary to enumerate all module
c66407fa
RS
804changes in this section of the C<perldelta> file. From 5.11.0 forward
805only notable updates (such as new or deprecated modules ) will be listed
806in this section. For a complete reference to the versions of modules
807shipped in a given release of perl, please see L<Module::CoreList>.
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808
809=head2 New Modules and Pragmata
810
811=over 4
812
813=item *
814
815C<autodie>
816
817This is a new lexically-scoped alternative for the C<Fatal> module.
818The bundled version is 2.06_01. Note that in this release, using a string
819eval when C<autodie> is in effect can cause the autodie behaviour to leak
820into the surrounding scope. See L<autodie/"BUGS"> for more details.
821
822=item *
823
824C<Compress::Raw::Bzip2>
825
826This has been added to the core (version 2.020).
827
828=item *
829
830C<parent>
831
832This pragma establishes an ISA relationship with base classes at compile
c66407fa
RS
833time. It provides the key feature of C<base> without further unwanted
834behaviors.
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835
836=item *
837
838C<Parse::CPAN::Meta>
839
840This has been added to the core (version 1.39).
841
842=back
843
844=head2 Pragmata Changes
845
846=over 4
847
848=item *
849
850C<overloading>
851
852See L</"The C<overloading> pragma"> above.
853
854=item *
855
856C<attrs>
857
858The C<attrs> pragma has been removed. It had been marked as deprecated since
8595.6.0.
860
861=item *
862
863C<charnames>
864
865The Unicode F<NameAliases.txt> database file has been added. This has the
866effect of adding some extra C<\N> character names that formerly wouldn't
867have been recognised; for example, C<"\N{LATIN CAPITAL LETTER GHA}">.
868
869=item *
870
871C<feature>
872
873The meaning of the C<:5.10> and C<:5.10.X> feature bundles has
874changed slightly. The last component, if any (i.e. C<X>) is simply ignored.
875This is predicated on the assumption that new features will not, in
876general, be added to maintenance releases. So C<:5.10> and C<:5.10.X>
877have identical effect. This is a change to the behaviour documented for
8785.10.0.
879
880=item *
881
882C<mro>
883
884Upgraded from version 1.00 to 1.01. Performance for single inheritance is 40%
885faster - see L</"Performance Enhancements"> below.
886
887C<mro> is now implemented as an XS extension. The documented interface has not
888changed. Code relying on the implementation detail that some C<mro::>
889methods happened to be available at all times gets to "keep both pieces".
890
891=item *
892
893C<diagnostics>
894
895Supports %.0f formatting internally.
896
897=item *
898
899C<overload>
900
901Allow overloading of 'qr'.
902
903=item *
904
905C<constant>
906
907Upgraded from version 1.19 to 1.20.
908
909=item *
910
911C<diagnostics>
912
c66407fa
RS
913This pragma no longer suppresses C<Use of uninitialized value in range
914(or flip)> warnings. [perl #71204]
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915
916=item *
917
918C<feature>
919
920Upgraded from 1.13 to 1.14. Added the C<unicode_strings> feature:
921
922 use feature "unicode_strings";
923
924This pragma turns on Unicode semantics for the case-changing operations
c66407fa
RS
925(C<uc>, C<lc>, C<ucfirst>, C<lcfirst>) on strings that don't have the
926internal UTF-8 flag set, but that contain single-byte characters between
927128 and 255.
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928
929=item *
930
931C<threads>
932
933Upgraded from version 1.74 to 1.75.
934
935=item *
936
937C<less>
938
c66407fa 939Upgraded from version 0.02 to 0.03.
3ab3a109 940
c66407fa
RS
941This version introduces the C<stash_name> method to allow subclasses of
942C<less> to pick where in %^H to store their stash.
3ab3a109
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943
944=item *
945
946C<version>
947
948Upgraded from version 0.77 to 0.81.
949
950This version adds support for L</Version number formats> as described earlier
951in this document and in its own documentation.
952
953=item *
954
955C<warnings>
956
957Upgraded from 1.07 to 1.09.
958
959Added new C<warnings::fatal_enabled()> function.
960This version adds the C<illegalproto> warning category. See also L</New or
961Changed Diagnostics> for this change.
962
963=back
964
965
966=head2 Updated Modules
967
968=over 4
969
970=item XXX TODO RECALCULATE THIS VS 5.10.0
971
972=back
973
974=head2 Removed Modules and Pragmata
975
976=over 4
977
978=item *
979
980C<Devel::DProf::V>
981
982Removed from the Perl core. Prior version was 'undef'.
983
984=back
985
986=head1 Documentation
987
988=head2 New Documentation
989
990=over 4
991
992=item *
993
994L<perlhaiku>
995
996This contains instructions on how to build perl for the Haiku platform.
997
998=item *
999
1000L<perlmroapi>
1001
1002This describes the new interface for pluggable Method Resolution Orders.
1003
1004=item *
1005
1006L<perlperf>
1007
1008This document, by Richard Foley, provides an introduction to the use of
1009performance and optimization techniques which can be used with particular
1010reference to perl programs.
1011
1012=item *
1013
1014L<perlrepository>
1015
1016This describes how to access the perl source using the I<git> version
1017control system.
1018
1019=item *
1020
1021L<perlpolicy> extends the "Social contract about contributed modules" into
1022the beginnings of a document on Perl porting policies.
1023
1024=back
1025
1026=head2 Changes to Existing Documentation
1027
1028The various large F<Changes*> files (which listed every change made to perl
1029over the last 18 years) have been removed, and replaced by a small file,
1030also called F<Changes>, which just explains how that same information may
1031be extracted from the git version control system.
1032
1033The file F<Porting/patching.pod> has been deleted, as it mainly described
1034interacting with the old Perforce-based repository, which is now obsolete.
1035Information still relevant has been moved to L<perlrepository>.
1036
1037L<perlapi>, L<perlintern>, L<perlmodlib> and L<perltoc> are now all
1038generated at build time, rather than being shipped as part of the release.
1039
1040=over
1041
1042=item *
1043
1044Documented -X overloading.
1045
1046=item *
1047
1048Documented that C<when()> treats specially most of the filetest operators
1049
1050=item *
1051
c66407fa 1052Documented C<when> as a syntax modifier
3ab3a109
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1053
1054=item *
1055
c66407fa 1056Eliminated "Old Perl threads tutorial", which described 5005 threads.
3ab3a109
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1057
1058F<pod/perlthrtut.pod> is the same material reworked for ithreads.
1059
1060=item *
1061
1062Correct previous documentation: v-strings are not deprecated
1063
1064With version objects, we need them to use MODULE VERSION syntax. This
c66407fa 1065patch removes the deprecation notice.
3ab3a109
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1066
1067=item *
1068
1069Added security contact information to L<perlsec>
1070
1071A significant fraction of the core documentation has been updated to clarify
1072the behavior of Perl's Unicode handling.
1073
1074Much of the remaining core documentation has been reviewed and edited
1075for clarity, consistent use of language, and to fix the spelling of Tom
1076Christiansen's name.
1077
1078The Pod specification (L<perlpodspec>) has been updated to bring the
c66407fa
RS
1079specification in line with modern usage already supported by most Pod
1080systems. A parameter string may now follow the format name in a
1081"begin/end" region. Links to URIs with a text description are now
1082allowed. The usage of C<LE<lt>"section"E<gt>> has been marked as
1083deprecated.
3ab3a109
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1084
1085L<if.pm|if> has been documented in L<perlfunc/use> as a means to get
c66407fa
RS
1086conditional loading of modules despite the implicit BEGIN block around
1087C<use>.
3ab3a109
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1088
1089=item *
1090
c66407fa 1091The documentation for C<$1> in perlvar.pod has been clarified.
3ab3a109 1092
a620a577
KW
1093=item *
1094
1095C<\N{U+I<wide hex char>}> is now documented.
1096
3ab3a109
JV
1097=back
1098
1099=head1 Performance Enhancements
1100
1101=over 4
1102
1103=item *
1104
1105A new internal cache means that C<isa()> will often be faster.
1106
1107=item *
1108
1109The implementation of C<C3> Method Resolution Order has been optimised -
1110linearisation for classes with single inheritance is 40% faster. Performance
1111for multiple inheritance is unchanged.
1112
1113=item *
1114
1115Under C<use locale>, the locale-relevant information is now cached on
1116read-only values, such as the list returned by C<keys %hash>. This makes
1117operations such as C<sort keys %hash> in the scope of C<use locale> much
1118faster.
1119
1120=item *
1121
1122Empty C<DESTROY> methods are no longer called.
1123
1124=item *
1125
1126Faster C<Perl_sv_utf8_upgrade()>
1127
1128=item *
1129
1130Speed up C<keys> on empty hash
1131
1132=item *
1133
1134C<if (%foo)> has been optimized to be faster than C<if (keys %foo)>
1135
1136=item *
1137
1138Reversing an array to itself (as in C<@a = reverse @a>) in void context
1139now happens in-place and is several orders of magnitude faster than it
1140used to be. It will also preserve non-existent elements whenever
1141possible, i.e. for non magical arrays or tied arrays with C<EXISTS> and
1142C<DELETE> methods.
1143
1144=back
1145
1146=head1 Installation and Configuration Improvements
1147
1148=head2 F<ext/> reorganisation
1149
1150The layout of directories in F<ext> has been revised. Specifically, all
1151extensions are now flat, and at the top level, with C</> in pathnames
1152replaced by C<->, so that F<ext/Data/Dumper/> is now F<ext/Data-Dumper/>,
1153etc. The names of the extensions as specified to F<Configure>, and as
1154reported by C<%Config::Config> under the keys C<dynamic_ext>,
1155C<known_extensions>, C<nonxs_ext> and C<static_ext> have not changed, and
1156still use C</>. Hence this change will not have any affect once perl is
1157installed. C<Safe> has been split out from being part of C<Opcode>, and
1158C<mro> is now an extension in its own right.
1159
1160Nearly all dual-life modules have been moved from F<lib> to F<ext>, and will
1161now appear as known C<nonxs_ext>. This will made no difference to the
1162structure of an installed perl, nor will the modules installed differ,
1163unless you run F<Configure> with options to specify an exact list of
1164extensions to build. In this case, you will rapidly become aware that you
1165need to add to your list, because various modules needed to complete the
1166build, such as C<ExtUtils::ParseXS>, have now become extensions, and
1167without them the build will fail well before it attempts to run the
1168regression tests.
1169
1170=head2 Configuration improvements
1171
1172If C<vendorlib> and C<vendorarch> are the same, then they are only added to
1173C<@INC> once.
1174
1175C<$Config{usedevel}> and the C-level C<PERL_USE_DEVEL> are now defined if
1176perl is built with C<-Dusedevel>.
1177
1178F<Configure> will enable use of C<-fstack-protector>, to provide protection
1179against stack-smashing attacks, if the compiler supports it.
1180
1181F<Configure> will now determine the correct prototypes for re-entrant
c66407fa 1182functions and for C<gconvert> if you are using a C++ compiler rather
3ab3a109
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1183than a C compiler.
1184
1185On Unix, if you build from a tree containing a git repository, the
1186configuration process will note the commit hash you have checked out, for
1187display in the output of C<perl -v> and C<perl -V>. Unpushed local commits
1188are automatically added to the list of local patches displayed by
1189C<perl -V>.
1190
1191USE_ATTRIBUTES_FOR_PERLIO is now reported in the compile-time options
1192listed by the C<-V> switch.
1193
1194=head2 Compilation improvements
1195
1196As part of the flattening of F<ext>, all extensions on all platforms are
1197built by F<make_ext.pl>. This replaces the Unix-specific
1198F<ext/util/make_ext>, VMS-specific F<make_ext.com> and Win32-specific
1199F<win32/buildext.pl>.
1200
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1201=head1 Changed Internals
1202
1203=over 4
1204
1205=item *
1206
1207C<Perl_pmflag> has been removed from the public API. Calling it now
1208generates a deprecation warning, and it will be removed in a future
1209release. Although listed as part of the API, it was never documented,
1210and only ever used in F<toke.c>, and prior to 5.10, F<regcomp.c>. In
1211core, it has been replaced by a static function.
1212
1213=item *
1214
1215Perl_magic_setmglob now knows about globs, fixing RT #71254.
1216
1217=item *
1218
1219TODO: C<SVt_RV> is gone. RVs are now stored in IVs
1220
1221=item *
1222
1223TODO: REGEXPs are first class
1224
1225=item *
1226
1227TODO: OOK is reworked, such that an OOKed scalar is PV not PVIV
1228
1229=item *
1230
1231The J.R.R. Tolkien quotes at the head of C source file have been checked and
1232proper citations added, thanks to a patch from Tom Christiansen.
1233
1234=item *
1235
1236C<Perl_vcroak()> now accepts a null first argument. In addition, a full audit
1237was made of the "not NULL" compiler annotations, and those for several
1238other internal functions were corrected.
1239
1240=item *
1241
1242New macros C<dSAVEDERRNO>, C<dSAVE_ERRNO>, C<SAVE_ERRNO>, C<RESTORE_ERRNO>
1243have been added to formalise the temporary saving of the C<errno>
1244variable.
1245
1246=item *
1247
1248The function C<Perl_sv_insert_flags> has been added to augment
1249C<Perl_sv_insert>.
1250
1251=item *
1252
1253The function C<Perl_newSV_type(type)> has been added, equivalent to
1254C<Perl_newSV()> followed by C<Perl_sv_upgrade(type)>.
1255
1256=item *
1257
1258The function C<Perl_newSVpvn_flags()> has been added, equivalent to
1259C<Perl_newSVpvn()> and then performing the action relevant to the flag.
1260
1261Two flag bits are currently supported.
1262
1263=over 4
1264
1265=item *
1266
1267C<SVf_UTF8>
1268
1269This will call C<SvUTF8_on()> for you. (Note that this does not convert an
1270sequence of ISO 8859-1 characters to UTF-8). A wrapper, C<newSVpvn_utf8()>
1271is available for this.
1272
1273=item *
1274
1275C<SVs_TEMP>
1276
1277Call C<Perl_sv_2mortal()> on the new SV.
1278
1279=back
1280
1281There is also a wrapper that takes constant strings, C<newSVpvs_flags()>.
1282
1283=item *
1284
1285The function C<Perl_croak_xs_usage> has been added as a wrapper to
1286C<Perl_croak>.
1287
1288=item *
1289
1290The functions C<PerlIO_find_layer> and C<PerlIO_list_alloc> are now
1291exported.
1292
1293=item *
1294
1295C<PL_na> has been exterminated from the core code, replaced by local STRLEN
1296temporaries, or C<*_nolen()> calls. Either approach is faster than C<PL_na>,
17270880 1297which is a pointer dereference into the interpreter structure under ithreads,
3ab3a109
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1298and a global variable otherwise.
1299
1300=item *
1301
1302C<Perl_mg_free()> used to leave freed memory accessible via C<SvMAGIC()> on
1303the scalar. It now updates the linked list to remove each piece of magic
1304as it is freed.
1305
1306=item *
1307
1308Under ithreads, the regex in C<PL_reg_curpm> is now reference counted. This
1309eliminates a lot of hackish workarounds to cope with it not being reference
1310counted.
1311
1312=item *
1313
1314C<Perl_mg_magical()> would sometimes incorrectly turn on C<SvRMAGICAL()>.
1315This has been fixed.
1316
1317=item *
1318
1319The I<public> IV and NV flags are now not set if the string value has
1320trailing "garbage". This behaviour is consistent with not setting the
1321public IV or NV flags if the value is out of range for the type.
1322
1323=item *
1324
1325SV allocation tracing has been added to the diagnostics enabled by C<-Dm>.
1326The tracing can alternatively output via the C<PERL_MEM_LOG> mechanism, if
1327that was enabled when the F<perl> binary was compiled.
1328
1329=item *
1330
1331Smartmatch resolution tracing has been added as a new diagnostic. Use C<-DM> to
1332enable it.
1333
1334=item *
1335
1336A new debugging flag C<-DB> now dumps subroutine definitions, leaving
1337C<-Dx> for its original purpose of dumping syntax trees.
1338
1339=item *
1340
1341Uses of C<Nullav>, C<Nullcv>, C<Nullhv>, C<Nullop>, C<Nullsv> etc have been
1342replaced by C<NULL> in the core code, and non-dual-life modules, as C<NULL>
1343is clearer to those unfamiliar with the core code.
1344
1345=item *
1346
1347A macro C<MUTABLE_PTR(p)> has been added, which on (non-pedantic) gcc will
1348not cast away C<const>, returning a C<void *>. Macros C<MUTABLE_SV(av)>,
1349C<MUTABLE_SV(cv)> etc build on this, casting to C<AV *> etc without
1350casting away C<const>. This allows proper compile-time auditing of
1351C<const> correctness in the core, and helped picked up some errors (now
1352fixed).
1353
1354=item *
1355
1356Macros C<mPUSHs()> and C<mXPUSHs()> have been added, for pushing SVs on the
1357stack and mortalizing them.
1358
1359=item *
1360
1361Use of the private structure C<mro_meta> has changed slightly. Nothing
1362outside the core should be accessing this directly anyway.
1363
1364=item *
1365
1366A new tool, F<Porting/expand-macro.pl> has been added, that allows you
1367to view how a C preprocessor macro would be expanded when compiled.
1368This is handy when trying to decode the macro hell that is the perl
1369guts.
1370
1371=back
1372
1373=head1 Testing
1374
1375=head2 New Tests
1376
1377Many modules updated from CPAN incorporate new tests.
1378Several tests that have the potential to hang forever if they fail now
1379incorporate a "watchdog" functionality that will kill them after a timeout,
1380which helps ensure that C<make test> and C<make test_harness> run to
1381completion automatically. (Jerry Hedden).
1382
1383Some core-specific tests have been added:
1384
1385=over 4
1386
1387=item *
1388
1389Significant cleanups to core tests to ensure that language and
1390interpreter features are not used before they're tested.
1391
1392=item *
1393
c66407fa
RS
1394C<make test_porting> now runs a number of important pre-commit checks
1395which might be of use to anyone working on the Perl core.
3ab3a109
JV
1396
1397=item *
1398
1399F<t/porting/podcheck.t> automatically checks the well-formedness of
1400POD found in all .pl, .pm and .pod files in the F<MANIFEST>, other than in
1401dual-lifed modules which are primarily maintained outside the Perl core.
1402
1403=item *
1404
1405F<t/porting/manifest.t> now tests that all files listed in MANIFEST are present.
1406
1407=item *
1408
1409F<t/op/while_readdir.t>
1410
1411Test that a bare readdir in while loop sets $_.
1412
1413=item *
1414
c66407fa 1415F<t/comp/retainedlines.t>
3ab3a109
JV
1416
1417Check that the debugger can retain source lines from C<eval>.
1418
1419=item *
1420
c66407fa 1421F<t/io/perlio_fail.t>
3ab3a109
JV
1422
1423Check that bad layers fail.
1424
1425=item *
1426
c66407fa 1427F<t/io/perlio_leaks.t>
3ab3a109
JV
1428
1429Check that PerlIO layers are not leaking.
1430
1431=item *
1432
c66407fa 1433F<t/io/perlio_open.t>
3ab3a109
JV
1434
1435Check that certain special forms of open work.
1436
1437=item *
1438
c66407fa 1439F<t/io/perlio.t>
3ab3a109
JV
1440
1441General PerlIO tests.
1442
1443=item *
1444
c66407fa 1445F<t/io/pvbm.t>
3ab3a109
JV
1446
1447Check that there is no unexpected interaction between the internal types
1448C<PVBM> and C<PVGV>.
1449
1450=item *
1451
c66407fa 1452F<t/mro/package_aliases.t>
3ab3a109
JV
1453
1454Check that mro works properly in the presence of aliased packages.
1455
1456=item *
1457
c66407fa 1458F<t/op/dbm.t>
3ab3a109
JV
1459
1460Tests for C<dbmopen> and C<dbmclose>.
1461
1462=item *
1463
c66407fa 1464F<t/op/index_thr.t>
3ab3a109
JV
1465
1466Tests for the interaction of C<index> and threads.
1467
1468=item *
1469
c66407fa 1470F<t/op/pat_thr.t>
3ab3a109
JV
1471
1472Tests for the interaction of esoteric patterns and threads.
1473
1474=item *
1475
c66407fa 1476F<t/op/qr_gc.t>
3ab3a109
JV
1477
1478Test that C<qr> doesn't leak.
1479
1480=item *
1481
c66407fa 1482F<t/op/reg_email_thr.t>
3ab3a109
JV
1483
1484Tests for the interaction of regex recursion and threads.
1485
1486=item *
1487
c66407fa 1488F<t/op/regexp_qr_embed_thr.t>
3ab3a109
JV
1489
1490Tests for the interaction of patterns with embedded C<qr//> and threads.
1491
1492=item *
1493
c66407fa 1494F<t/op/regexp_unicode_prop.t>
3ab3a109
JV
1495
1496Tests for Unicode properties in regular expressions.
1497
1498=item *
1499
c66407fa 1500F<t/op/regexp_unicode_prop_thr.t>
3ab3a109
JV
1501
1502Tests for the interaction of Unicode properties and threads.
1503
1504=item *
1505
c66407fa 1506F<t/op/reg_nc_tie.t>
3ab3a109
JV
1507
1508Test the tied methods of C<Tie::Hash::NamedCapture>.
1509
1510=item *
1511
c66407fa 1512F<t/op/reg_posixcc.t>
3ab3a109
JV
1513
1514Check that POSIX character classes behave consistently.
1515
1516=item *
1517
c66407fa 1518F<t/op/re.t>
3ab3a109
JV
1519
1520Check that exportable C<re> functions in F<universal.c> work.
1521
1522=item *
1523
c66407fa 1524F<t/op/setpgrpstack.t>
3ab3a109
JV
1525
1526Check that C<setpgrp> works.
1527
1528=item *
1529
c66407fa 1530F<t/op/substr_thr.t>
3ab3a109
JV
1531
1532Tests for the interaction of C<substr> and threads.
1533
1534=item *
1535
c66407fa 1536F<t/op/upgrade.t>
3ab3a109
JV
1537
1538Check that upgrading and assigning scalars works.
1539
1540=item *
1541
c66407fa 1542F<t/uni/lex_utf8.t>
3ab3a109
JV
1543
1544Check that Unicode in the lexer works.
1545
1546=item *
1547
c66407fa 1548F<t/uni/tie.t>
3ab3a109
JV
1549
1550Check that Unicode and C<tie> work.
1551
1552=item *
1553
c66407fa 1554F<t/comp/final_line_num.t>
3ab3a109
JV
1555
1556See if line numbers are correct at EOF
1557
1558=item *
1559
c66407fa 1560F<t/comp/form_scope.t>
3ab3a109
JV
1561
1562See if format scoping works
1563
1564=item *
1565
c66407fa 1566F<t/comp/line_debug.t>
3ab3a109 1567
c66407fa 1568See if C<< @{"_<$file"} >> works
3ab3a109
JV
1569
1570=item *
1571
c66407fa 1572F<t/op/filetest_t.t>
3ab3a109
JV
1573
1574See if -t file test works
1575
1576=item *
1577
c66407fa 1578F<t/op/qr.t>
3ab3a109
JV
1579
1580See if qr works
1581
1582=item *
1583
c66407fa 1584F<t/op/utf8cache.t>
3ab3a109
JV
1585
1586Tests malfunctions of utf8 cache
1587
1588=item *
1589
c66407fa 1590F<t/re/uniprops.t>
3ab3a109
JV
1591
1592Test unicode \p{} regex constructs
1593
1594=back
1595
1596=head2 Testing improvements
1597
1598=over 4
1599
1600=item *
1601
1602It's now possible to override C<PERL5OPT> and friends in F<t/TEST>
1603
1604=back
1605
1606
1607=head1 New or Changed Diagnostics
1608
1609Several new diagnostics, see L<perldiag> for details.
1610
1611=over 4
1612
1613=item *
1614
1615C<Bad plugin affecting keyword '%s'>
1616
1617=item *
1618
1619C<gmtime(%.0f) too large>
1620
1621=item *
1622
1623C<Lexing code attempted to stuff non-Latin-1 character into Latin-1 input>
1624
1625=item *
1626
1627C<Lexing code internal error (%s)>
1628
1629=item *
1630
1631C<localtime(%.0f) too large>
1632
1633=item *
1634
1635C<Overloaded dereference did not return a reference>
1636
1637=item *
1638
1639C<Overloaded qr did not return a REGEXP>
1640
1641=item *
1642
1643C<Perl_pmflag() is deprecated, and will be removed from the XS API>
1644
1645=item *
1646
1647New warning category C<illegalproto>
1648
1649The two warnings :
1650
1651 Illegal character in prototype for %s : %s
1652 Prototype after '%c' for %s : %s
1653
1654have been moved from the C<syntax> top-level warnings category into a new
1655first-level category, C<illegalproto>. These two warnings are currently the
1656only ones emitted during parsing of an invalid/illegal prototype, so one
1657can now do
1658
1659 no warnings 'illegalproto';
1660
1661to suppress only those, but not other syntax-related warnings. Warnings where
1662prototypes are changed, ignored, or not met are still in the C<prototype>
1663category as before. (Matt S. Trout)
1664
1665=item *
1666
1667lvalue attribute ignored after the subroutine has been defined
1668
1669This new warning is issued when one attempts to mark a subroutine as
1670lvalue after it has been defined.
1671
1672=item *
1673
c66407fa
RS
1674warn if C<++> or C<--> are unable to change the value because it's
1675beyond the limit of representation
3ab3a109
JV
1676
1677This uses a new warnings category: "imprecision".
1678
1679=item *
c66407fa
RS
1680
1681C<lc>, C<uc>, C<lcfirst>, and C<ucfirst> warn when passed undef.
3ab3a109
JV
1682
1683=item *
1684
1685Show constant in "Useless use of a constant in void context"
1686
1687=item *
1688
1689Make the new warning report undef constants as undef
1690
1691=item *
1692
1693Add a new warning, "Prototype after '%s'"
1694
1695=item *
1696
c66407fa
RS
1697Tweak the "Illegal character in prototype" warning so it's more precise
1698when reporting illegal characters after _
3ab3a109
JV
1699
1700=item *
1701
c66407fa 1702Correct the unintended interpolation of C<$\> in regex
3ab3a109
JV
1703
1704=item *
1705
c66407fa
RS
1706Make overflow warnings in C<gmtime> and C<localtime> only occur when
1707warnings are enabled
3ab3a109
JV
1708
1709=item *
1710
1711Improve mro merging error messages.
1712
1713They are now very similar to those produced by Algorithm::C3.
1714
1715=item *
1716
1717Amelioration of the error message "Unrecognized character %s in column %d"
1718
1719Changes the error message to "Unrecognized character %s; marked by E<lt>--
1720HERE after %sE<lt>-- HERE near column %d". This should make it a little
1721simpler to spot and correct the suspicious character.
1722
1723=item *
1724
c66407fa
RS
1725Explicitely point to C<$.> when it causes an uninitialized warning for
1726ranges in scalar context
3ab3a109
JV
1727
1728=item *
1729
3ab3a109
JV
1730C<split> now warns when called in void context
1731
1732=item *
1733
1734C<printf>-style functions called with too few arguments will now issue the
1735warning C<"Missing argument in %s"> [perl #71000]
1736
1737=item *
1738
1739C<panic: sv_chop %s>
1740
1741This new fatal error occurs when the C routine C<Perl_sv_chop()> was
1742passed a position that is not within the scalar's string buffer. This
1743could be caused by buggy XS code, and at this point recovery is not
1744possible.
1745
1746=item *
1747
3ab3a109
JV
1748C<Deep recursion on subroutine "%s">
1749
1750It is now possible to change the depth threshold for this warning from the
1751default of 100, by recompiling the F<perl> binary, setting the C
1752pre-processor macro C<PERL_SUB_DEPTH_WARN> to the desired value.
1753
1754=item *
1755
1756Perl now properly returns a syntax error instead of segfaulting
c66407fa 1757if C<each>, C<keys>, or C<values> is used without an argument.
3ab3a109
JV
1758
1759=item *
1760
c66407fa
RS
1761C<tell()> now fails properly if called without an argument and when no
1762previous file was read.
3ab3a109 1763
c66407fa
RS
1764C<tell()> now returns C<-1>, and sets errno to C<EBADF>, thus restoring
1765the 5.8.x behaviour.
3ab3a109
JV
1766
1767=item *
1768
c66407fa
RS
1769C<overload> no longer implicitly unsets fallback on repeated 'use
1770overload' lines.
3ab3a109
JV
1771
1772=item *
1773
1774POSIX::strftime() can now handle Unicode characters in the format string.
1775
1776=item *
1777
c66407fa
RS
1778The Windows select() implementation now supports all empty C<fd_set>s
1779more correctly.
3ab3a109
JV
1780
1781=item *
1782
c66407fa
RS
1783The "syntax" category was removed from 5 warnings that should only be in
1784"deprecated".
3ab3a109
JV
1785
1786=item *
1787
c66407fa
RS
1788Three fatal C<pack>/C<unpack> error messages have been normalized to
1789"panic: %s"
3ab3a109
JV
1790
1791=item *
1792
1793"Unicode character is illegal" has been rephrased to be more accurate
1794
1795It now reads C<Unicode non-character is illegal in interchange> and the
1796perldiag documentation has been expanded a bit.
1797
1798=item *
1799
c66407fa
RS
1800Perl now defaults to issuing a warning if a deprecated language feature
1801is used.
3ab3a109
JV
1802
1803To disable this feature in a given lexical scope, you should use C<no
1804warnings 'deprecated';> For information about which language features
1805are deprecated and explanations of various deprecation warnings, please
1806see L<perldiag.pod>
1807
1808=back
1809
c66407fa
RS
1810The following diagnostics have been removed:
1811
1812=over 4
1813
1814=item *
1815
1816C<Runaway format>
1817
1818=item *
1819
1820C<Can't locate package %s for the parents of %s>
1821
1822This warning has been removed. In general, it only got produced in
1823conjunction with other warnings, and removing it allowed an ISA lookup
1824optimisation to be added.
1825
1826=item *
1827
1828C<v-string in use/require is non-portable>
1829
1830=back
1831
3ab3a109
JV
1832=head1 Utility Changes
1833
1834=over 4
1835
1836=item *
1837
1838F<h2ph>
1839
1840Now looks in C<include-fixed> too, which is a recent addition to gcc's
1841search path.
1842
1843=item *
1844
1845F<h2xs>
1846
1847No longer incorrectly treats enum values like macros (Daniel Burr).
1848
1849Now handles C++ style constants (C<//>) properly in enums. (A patch from
1850Rainer Weikusat was used; Daniel Burr also proposed a similar fix).
1851
1852=item *
1853
1854F<perl5db.pl>
1855
1856C<LVALUE> subroutines now work under the debugger.
1857
1858The debugger now correctly handles proxy constant subroutines, and
1859subroutine stubs.
1860
1861=item *
1862
1863F<perlbug>
1864
1865F<perlbug> now uses C<%Module::CoreList::bug_tracker> to print out upstream bug
1866tracker URLs.
1867
1868Where the user names a module that their bug report is about, and we know the
1869URL for its upstream bug tracker, provide a message to the user explaining
1870that the core copies the CPAN version directly, and provide the URL for
1871reporting the bug directly to upstream.
1872
1873=item *
1874
1875F<perlthanks>
1876
1877Perl 5.11.0 added a new utility F<perlthanks>, which is a variant of
1878F<perlbug>, but for sending non-bug-reports to the authors and maintainers
1879of Perl. Getting nothing but bug reports can become a bit demoralising:
1880we'll see if this changes things.
1881
1882=item *
1883
1884F<perlbug>
1885
1886No longer reports "Message sent" when it hasn't actually sent the message
1887
1888=item *
1889
1890F<a2p>
1891
1892Fixed bugs with the match() operator in list context, remove mention of
c66407fa 1893C<$[>.
3ab3a109
JV
1894
1895=back
1896
1897=head1 Selected Bug Fixes
1898
1899=over 4
1900
1901=item *
1902
1903Ensure that pp_qr returns a new regexp SV each time. Resolves RT #69852.
1904
1905Instead of returning a(nother) reference to the (pre-compiled) regexp in the
1906optree, use reg_temp_copy() to create a copy of it, and return a reference to
1907that. This resolves issues about Regexp::DESTROY not being called in a timely
1908fashion (the original bug tracked by RT #69852), as well as bugs related to
1909blessing regexps, and of assigning to regexps, as described in correspondence
1910added to the ticket.
1911
1912It transpires that we also need to undo the SvPVX() sharing when ithreads
1913cloning a Regexp SV, because mother_re is set to NULL, instead of a cloned
1914copy of the mother_re. This change might fix bugs with regexps and threads in
1915certain other situations, but as yet neither tests nor bug reports have
1916indicated any problems, so it might not actually be an edge case that it's
1917possible to reach.
1918
1919=item *
1920
3ab3a109
JV
1921Several compilation errors and segfaults when perl was built with C<-Dmad> were fixed.
1922
1923=item *
1924
1925Fixes for lexer API changes in 5.11.2 which broke NYTProf's savesrc option.
1926
1927=item *
1928
c66407fa 1929C<-t> should only return TRUE for file handles connected to a TTY
3ab3a109 1930
c66407fa
RS
1931The Microsoft C version of C<isatty()> returns TRUE for all
1932character mode devices, including the F</dev/null>-style "nul"
3ab3a109
JV
1933device and printers like "lpt1".
1934
1935=item *
1936
1937Fixed a regression caused by commit fafafbaf which caused a panic during
1938parameter passing [perl #70171]
1939
1940=item *
1941
1942On systems which in-place edits without backup files, -i'*' now works as
1943the documentation says it does [perl #70802]
1944
1945=item *
1946
1947Saving and restoring magic flags no longer loses readonly flag.
1948
1949=item *
1950
1951The malformed syntax C<grep EXPR LIST> (note the missing comma) no longer
1952causes abrupt and total failure.
1953
1954=item *
1955
1956Regular expressions compiled with C<qr{}> literals properly set C<$'> when
1957matching again.
1958
1959=item *
1960
1961Using named subroutines with C<sort> should no longer lead to bus errors [perl
1962#71076]
1963
1964=item *
1965
1966Numerous bugfixes catch small issues caused by the recently-added Lexer API.
1967
1968=item *
1969
1970Smart match against C<@_> sometimes gave false negatives. [perl #71078]
1971
1972=item *
1973
c66407fa
RS
1974C<$@> may now be assigned a read-only value (without error or busting
1975the stack).
3ab3a109
JV
1976
1977=item *
1978
1979C<sort> called recursively from within an active comparison subroutine no
1980longer causes a bus error if run multiple times. [perl #71076]
1981
1982=item *
1983
c66407fa 1984Tie::Hash::NamedCapture::* will not abort if passed bad input (RT #71828)
3ab3a109
JV
1985
1986=item *
1987
1988@_ and $_ no longer leak under threads (RT #34342 and #41138, also
1989#70602, #70974)
1990
1991=item *
1992
1993C<-I> on shebang line now adds directories in front of @INC
1994as documented, and as does C<-I> when specified on the command-line.
1995
1996=item *
1997
1998C<kill> is now fatal when called on non-numeric process identifiers.
c66407fa
RS
1999Previously, an C<undef> process identifier would be interpreted as a
2000request to kill process 0, which would terminate the current process
2001group on POSIX systems. Since process identifiers are always integers,
2002killing a non-numeric process is now fatal.
3ab3a109
JV
2003
2004=item *
2005
20065.10.0 inadvertently disabled an optimisation, which caused a measurable
2007performance drop in list assignment, such as is often used to assign
2008function parameters from C<@_>. The optimisation has been re-instated, and
c66407fa 2009the performance regression fixed. (This fix is also present in 5.10.1)
3ab3a109
JV
2010
2011=item *
2012
2013Fixed memory leak on C<while (1) { map 1, 1 }> [RT #53038].
2014
2015=item *
2016
2017Some potential coredumps in PerlIO fixed [RT #57322,54828].
2018
2019=item *
2020
2021The debugger now works with lvalue subroutines.
2022
2023=item *
2024
2025The debugger's C<m> command was broken on modules that defined constants
2026[RT #61222].
2027
2028=item *
2029
2030C<crypt> and string complement could return tainted values for untainted
2031arguments [RT #59998].
2032
2033=item *
2034
2035The C<-i>I<.suffix> command-line switch now recreates the file using
2036restricted permissions, before changing its mode to match the original
2037file. This eliminates a potential race condition [RT #60904].
2038
2039=item *
2040
2041On some Unix systems, the value in C<$?> would not have the top bit set
2042(C<$? & 128>) even if the child core dumped.
2043
2044=item *
2045
2046Under some circumstances, C<$^R> could incorrectly become undefined
2047[RT #57042].
2048
2049=item *
2050
2051In the XS API, various hash functions, when passed a pre-computed hash where
2052the key is UTF-8, might result in an incorrect lookup.
2053
2054=item *
2055
2056XS code including F<XSUB.h> before F<perl.h> gave a compile-time error
2057[RT #57176].
2058
2059=item *
2060
2061C<< $object-E<gt>isa('Foo') >> would report false if the package C<Foo> didn't
2062exist, even if the object's C<@ISA> contained C<Foo>.
2063
2064=item *
2065
2066Various bugs in the new-to 5.10.0 mro code, triggered by manipulating
2067C<@ISA>, have been found and fixed.
2068
2069=item *
2070
2071Bitwise operations on references could crash the interpreter, e.g.
2072C<$x=\$y; $x |= "foo"> [RT #54956].
2073
2074=item *
2075
2076Patterns including alternation might be sensitive to the internal UTF-8
2077representation, e.g.
2078
2079 my $byte = chr(192);
2080 my $utf8 = chr(192); utf8::upgrade($utf8);
2081 $utf8 =~ /$byte|X}/i; # failed in 5.10.0
2082
2083=item *
2084
2085Within UTF8-encoded Perl source files (i.e. where C<use utf8> is in
2086effect), double-quoted literal strings could be corrupted where a C<\xNN>,
2087C<\0NNN> or C<\N{}> is followed by a literal character with ordinal value
2088greater than 255 [RT #59908].
2089
2090=item *
2091
2092C<B::Deparse> failed to correctly deparse various constructs:
2093C<readpipe STRING> [RT #62428], C<CORE::require(STRING)> [RT #62488],
2094C<sub foo(_)> [RT #62484].
2095
2096=item *
2097
2098Using C<setpgrp> with no arguments could corrupt the perl stack.
2099
2100=item *
2101
2102The block form of C<eval> is now specifically trappable by C<Safe> and
2103C<ops>. Previously it was erroneously treated like string C<eval>.
2104
2105=item *
2106
2107In 5.10.0, the two characters C<[~> were sometimes parsed as the smart
2108match operator (C<~~>) [RT #63854].
2109
2110=item *
2111
2112In 5.10.0, the C<*> quantifier in patterns was sometimes treated as
2113C<{0,32767}> [RT #60034, #60464]. For example, this match would fail:
2114
2115 ("ab" x 32768) =~ /^(ab)*$/
2116
2117=item *
2118
2119C<shmget> was limited to a 32 bit segment size on a 64 bit OS [RT #63924].
2120
2121=item *
2122
2123Using C<next> or C<last> to exit a C<given> block no longer produces a
2124spurious warning like the following:
2125
2126 Exiting given via last at foo.pl line 123
2127
2128=item *
2129
2130On Windows, C<'.\foo'> and C<'..\foo'> were treated differently than
2131C<'./foo'> and C<'../foo'> by C<do> and C<require> [RT #63492].
2132
2133=item *
2134
2135Assigning a format to a glob could corrupt the format; e.g.:
2136
2137 *bar=*foo{FORMAT}; # foo format now bad
2138
2139=item *
2140
2141Attempting to coerce a typeglob to a string or number could cause an
2142assertion failure. The correct error message is now generated,
2143C<Can't coerce GLOB to I<$type>>.
2144
2145=item *
2146
2147Under C<use filetest 'access'>, C<-x> was using the wrong access mode. This
2148has been fixed [RT #49003].
2149
2150=item *
2151
2152C<length> on a tied scalar that returned a Unicode value would not be
2153correct the first time. This has been fixed.
2154
2155=item *
2156
2157Using an array C<tie> inside in array C<tie> could SEGV. This has been
2158fixed. [RT #51636]
2159
2160=item *
2161
2162A race condition inside C<PerlIOStdio_close()> has been identified and
2163fixed. This used to cause various threading issues, including SEGVs.
2164
2165=item *
2166
2167In C<unpack>, the use of C<()> groups in scalar context was internally
2168placing a list on the interpreter's stack, which manifested in various
2169ways, including SEGVs. This is now fixed [RT #50256].
2170
2171=item *
2172
2173Magic was called twice in C<substr>, C<\&$x>, C<tie $x, $m> and C<chop>.
2174These have all been fixed.
2175
2176=item *
2177
2178A 5.10.0 optimisation to clear the temporary stack within the implicit
2179loop of C<s///ge> has been reverted, as it turned out to be the cause of
2180obscure bugs in seemingly unrelated parts of the interpreter [commit
2181ef0d4e17921ee3de].
2182
2183=item *
2184
2185The line numbers for warnings inside C<elsif> are now correct.
2186
2187=item *
2188
2189The C<..> operator now works correctly with ranges whose ends are at or
2190close to the values of the smallest and largest integers.
2191
2192=item *
2193
2194C<binmode STDIN, ':raw'> could lead to segmentation faults on some platforms.
2195This has been fixed [RT #54828].
2196
2197=item *
2198
2199An off-by-one error meant that C<index $str, ...> was effectively being
2200executed as C<index "$str\0", ...>. This has been fixed [RT #53746].
2201
2202=item *
2203
2204Various leaks associated with named captures in regexes have been fixed
2205[RT #57024].
2206
2207=item *
2208
2209A weak reference to a hash would leak. This was affecting C<DBI>
2210[RT #56908].
2211
2212=item *
2213
2214Using (?|) in a regex could cause a segfault [RT #59734].
2215
2216=item *
2217
2218Use of a UTF-8 C<tr//> within a closure could cause a segfault [RT #61520].
2219
2220=item *
2221
2222Calling C<Perl_sv_chop()> or otherwise upgrading an SV could result in an
2223unaligned 64-bit access on the SPARC architecture [RT #60574].
2224
2225=item *
2226
2227In the 5.10.0 release, C<inc_version_list> would incorrectly list
2228C<5.10.*> after C<5.8.*>; this affected the C<@INC> search order
2229[RT #67628].
2230
2231=item *
2232
2233In 5.10.0, C<pack "a*", $tainted_value> returned a non-tainted value
2234[RT #52552].
2235
2236=item *
2237
2238In 5.10.0, C<printf> and C<sprintf> could produce the fatal error
2239C<panic: utf8_mg_pos_cache_update> when printing UTF-8 strings
2240[RT #62666].
2241
2242=item *
2243
2244In the 5.10.0 release, a dynamically created C<AUTOLOAD> method might be
2245missed (method cache issue) [RT #60220,60232].
2246
2247=item *
2248
2249In the 5.10.0 release, a combination of C<use feature> and C<//ee> could
2250cause a memory leak [RT #63110].
2251
2252=item *
2253
2254C<-C> on the shebang (C<#!>) line is once more permitted if it is also
2255specified on the command line. C<-C> on the shebang line used to be a
2256silent no-op I<if> it was not also on the command line, so perl 5.10.0
2257disallowed it, which broke some scripts. Now perl checks whether it is
2258also on the command line and only dies if it is not [RT #67880].
2259
2260=item *
2261
2262In 5.10.0, certain types of re-entrant regular expression could crash,
2263or cause the following assertion failure [RT #60508]:
2264
2265 Assertion rx->sublen >= (s - rx->subbeg) + i failed
2266
2267=item *
2268
2269Previously missing files from Unicode 5.1 Character Database are now included.
2270
2271=item *
2272
2273C<TMPDIR> is now honored when opening an anonymous temporary file
2274
2275=back
2276
2277=head1 Platform Specific Changes
2278
2279=head2 New Platforms
2280
2281=over
2282
2283=item Haiku
2284
2285Patches from the Haiku maintainers have been merged in. Perl should now
2286build on Haiku.
2287
2288=item MirOS BSD
2289
2290Perl should now build on MirOS BSD.
2291
2292
2293=back
2294
2295=head2 Discontinued Platforms
2296
2297=over
2298
2299=item DomainOS
2300
2301Support for Apollo DomainOS was removed in Perl 5.11.0
2302
2303=item MachTen
2304
2305Support for Tenon Intersystems MachTen Unix layer for MacOS Classic was
2306removed in Perl 5.11.0
2307
2308=item MiNT
2309
2310Support for Atari MiNT was removed in Perl 5.11.0.
2311
2312=back
2313
2314=head2 Updated Platforms
2315
2316=over 4
2317
2318=item Darwin (Mac OS X)
2319
2320=over 4
2321
2322=item *
2323
2324Skip testing the be_BY.CP1131 locale on Darwin 10 (Mac OS X 10.6),
2325as it's still buggy.
2326
2327=item *
2328
2329Correct infelicities in the regexp used to identify buggy locales
2330on Darwin 8 and 9 (Mac OS X 10.4 and 10.5, respectively).
2331
2332=back
2333
2334=item DragonFly BSD
2335
2336=over 4
2337
2338=item *
2339
2340Fix thread library selection [perl #69686]
2341
2342=back
2343
2344=item Win32
2345
2346=over 4
2347
2348=item *
2349
2350Initial support for mingw64 is now available
2351
2352=item *
2353
c66407fa
RS
2354Various bits of Perl's build infrastructure are no longer converted to
2355win32 line endings at release time. If this hurts you, please report the
2356problem with the L<perlbug> program included with perl.
3ab3a109
JV
2357
2358=item *
2359
2360Always add a manifest resource to C<perl.exe> to specify the C<trustInfo>
2361settings for Windows Vista and later. Without this setting Windows
2362will treat C<perl.exe> as a legacy application and apply various
2363heuristics like redirecting access to protected file system areas
2364(like the "Program Files" folder) to the users "VirtualStore"
2365instead of generating a proper "permission denied" error.
2366
2367For VC8 and VC9 this manifest setting is automatically generated by
2368the compiler/linker (together with the binding information for their
2369respective runtime libraries); for all other compilers we need to
2370embed the manifest resource explicitly in the external resource file.
2371
2372This change also requests the Microsoft Common-Controls version 6.0
2373(themed controls introduced in Windows XP) via the dependency list
2374in the assembly manifest. For VC8 and VC9 this is specified using the
2375C</manifestdependency> linker commandline option instead.
2376
2377=item *
2378
2379Improved message window handling means that C<alarm> and C<kill> messages
2380will no longer be dropped under race conditions.
2381
2382=back
2383
2384=item cygwin
2385
2386=over 4
2387
2388=item *
2389
2390Enable IPv6 support on cygwin 1.7 and newer
2391
2392=back
2393
2394=item OpenVMS
2395
2396=over 4
2397
2398=item *
2399
2400Make -UDEBUGGING the default on VMS for 5.12.0.
2401
2402Like it has been everywhere else for ages and ages. Also make
2403command-line selection of -UDEBUGGING and -DDEBUGGING work in
2404configure.com; before the only way to turn it off was by saying
2405no in answer to the interactive question.
2406
2407=item *
2408
2409The default pipe buffer size on VMS has been updated to 8192 on 64-bit
2410systems.
2411
2412=item *
2413
2414Reads from the in-memory temporary files of C<PerlIO::scalar> used to fail
2415if C<$/> was set to a numeric reference (to indicate record-style reads).
2416This is now fixed.
2417
2418=item *
2419
2420VMS now supports C<getgrgid>.
2421
2422=item *
2423
2424Many improvements and cleanups have been made to the VMS file name handling
2425and conversion code.
2426
2427=item *
2428
2429Enabling the C<PERL_VMS_POSIX_EXIT> logical name now encodes a POSIX exit
2430status in a VMS condition value for better interaction with GNV's bash
2431shell and other utilities that depend on POSIX exit values. See
2432L<perlvms/"$?"> for details.
2433
2434=item *
2435
2436C<File::Copy> now detects Unix compatibility mode on VMS.
2437
2438=back
2439
2440=item AIX
2441
2442Removed F<libbsd> for AIX 5L and 6.1. Only C<flock()> was used from F<libbsd>.
2443
2444Removed F<libgdbm> for AIX 5L and 6.1. The F<libgdbm> is delivered as an
2445optional package with the AIX Toolbox. Unfortunately the 64 bit version
2446is broken.
2447
2448Hints changes mean that AIX 4.2 should work again.
2449
2450=item Cygwin
2451
2452On Cygwin we now strip the last number from the DLL. This has been the
2453behaviour in the cygwin.com build for years. The hints files have been
2454updated.
2455
2456
2457=item FreeBSD
2458
2459The hints files now identify the correct threading libraries on FreeBSD 7
2460and later.
2461
2462=item Irix
2463
2464We now work around a bizarre preprocessor bug in the Irix 6.5 compiler:
2465C<cc -E -> unfortunately goes into K&R mode, but C<cc -E file.c> doesn't.
2466
2467=item NetBSD
2468
2469Hints now supports versions 5.*.
2470
2471=item Stratus VOS
2472
2473Various changes from Stratus have been merged in.
2474
2475=item Symbian
2476
2477There is now support for Symbian S60 3.2 SDK and S60 5.0 SDK.
2478
2479=back
2480
2481=head1 Known Problems
2482
2483This is a list of some significant unfixed bugs, which are regressions
2484from either 5.10.0 or 5.8.x.
2485
2486=over 4
2487
2488=item *
2489
2490C<List::Util::first> misbehaves in the presence of a lexical C<$_>
2491(typically introduced by C<my $_> or implicitly by C<given>). The variable
2492which gets set for each iteration is the package variable C<$_>, not the
2493lexical C<$_> [RT #67694].
2494
2495A similar issue may occur in other modules that provide functions which
2496take a block as their first argument, like
2497
2498 foo { ... $_ ...} list
2499
2500=item *
2501
3ab3a109
JV
2502Some regexes may run much more slowly when run in a child thread compared
2503with the thread the pattern was compiled into [RT #55600].
2504
2505=item *
2506
3d3a8206
KW
2507Things like C<"\N{LATIN SMALL LIGATURE FF}" =~ /\N{LATIN SMALL LETTER F}+/>
2508will appear to hang as they get into a very long running loop [RT #72998].
2509
2510=item *
2511
3ab3a109
JV
2512Untriaged test crashes on Windows 2000
2513
2514Several porters have reported mysterious crashes when Perl's entire test suite is run after a build on certain Windows 2000 systems. When run by hand, the individual tests reportedly work fine.
2515
2516=item *
2517
2518Known test failures on VMS
2519
2520Perl 5.11.1 fails a small set of core and CPAN tests as of this release.
2521With luck, that'll be sorted out for 5.11.2
2522
2523=item *
2524
2525Known test failures on VMS
2526
2527Perl 5.11.2 fails a small set of core and CPAN tests as of this
2528release. With luck, that'll be sorted out for 5.11.3.
2529
2530=back
2531
2532=head1 Acknowledgements
2533
2534Perl 5.12.0 represents approximately two years of development since
2535Perl 5.10.0 and contains __ lines of changes across ___ files
2536from __ authors and committers:
2537
2538XXX TODO LIST
2539
2540Many of the changes included in this version originated in the CPAN
2541modules included in Perl's core. We're grateful to the entire CPAN
2542community for helping Perl to flourish.
2543
2544=head1 Reporting Bugs
2545
2546If you find what you think is a bug, you might check the articles
2547recently posted to the comp.lang.perl.misc newsgroup and the perl
2548bug database at L<http://rt.perl.org/perlbug/>. There may also be
2549information at L<http://www.perl.org/>, the Perl Home Page.
2550
2551If you believe you have an unreported bug, please run the B<perlbug>
2552program included with your release. Be sure to trim your bug down
2553to a tiny but sufficient test case. Your bug report, along with the
2554output of C<perl -V>, will be sent off to perlbug@perl.org to be
2555analyzed by the Perl porting team.
2556
2557If the bug you are reporting has security implications, which make it
2558inappropriate to send to a publicly archived mailing list, then please send
2559it to perl5-security-report@perl.org. This points to a closed subscription
2560unarchived mailing list, which includes all the core committers, who be able
2561to help assess the impact of issues, figure out a resolution, and help
2562co-ordinate the release of patches to mitigate or fix the problem across all
2563platforms on which Perl is supported. Please only use this address for
2564security issues in the Perl core, not for modules independently
2565distributed on CPAN.
2566
2567=head1 SEE ALSO
2568
2569The F<Changes> file for an explanation of how to view exhaustive details
2570on what changed.
2571
2572The F<INSTALL> file for how to build Perl.
2573
2574The F<README> file for general stuff.
2575
2576The F<Artistic> and F<Copying> files for copyright information.
2577
2578=cut