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1=encoding utf8
2
3=head1 NAME
4
5076a392 5perldelta - what is new for perl v5.14.0
c71a852f 6
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7=head1 DESCRIPTION
8
9This document describes differences between the 5.12.0 release and
10the 5.14.0 release.
11
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12If you are upgrading from an earlier release such as 5.10.0, first read
13L<perl5120delta>, which describes differences between 5.10.0 and
145.12.0.
15
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16Some of the bug fixes in this release have been backported to subsequent
17releases of 5.12.x. Those are indicated with the 5.12.x version in
18parentheses.
19
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20=head1 Notice
21
22XXX Any important notices here
23
24=head1 Core Enhancements
25
1f539a1a 26=head2 Unicode
5076a392 27
1f539a1a 28=head3 Unicode Version 6.0 is now supported (mostly)
5076a392 29
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30Perl comes with the Unicode 6.0 data base updated with
31L<Corrigendum #8|http://www.unicode.org/versions/corrigendum8.html>,
32with one exception noted below.
33See L<http://unicode.org/versions/Unicode6.0.0> for details on the new
34release. Perl does not support any Unicode provisional properties,
a3c24add 35including the new ones for this release.
5076a392 36
1f539a1a 37Unicode 6.0 has chosen to use the name C<BELL> for the character at U+1F514,
e1b1739f 38which is a symbol that looks like a bell, and is used in Japanese cell
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39phones. This conflicts with the long-standing Perl usage of having
40C<BELL> mean the ASCII C<BEL> character, U+0007. In Perl 5.14,
41C<\N{BELL}> will continue to mean U+0007, but its use will generate a
42deprecated warning message, unless such warnings are turned off. The
43new name for U+0007 in Perl will be C<ALERT>, which corresponds nicely
44with the existing shorthand sequence for it, C<"\a">. C<\N{BEL}> will
45mean U+0007, with no warning given. The character at U+1F514 will not
46have a name in 5.14, but can be referred to by C<\N{U+1F514}>. The plan
47is that in Perl 5.16, C<\N{BELL}> will refer to U+1F514, and so all code
48that uses C<\N{BELL}> should convert by then to using C<\N{ALERT}>,
49C<\N{BEL}>, or C<"\a"> instead.
5076a392 50
1f539a1a 51=head3 Full functionality for C<use feature 'unicode_strings'>
5076a392 52
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53This release provides full functionality for C<use feature
54'unicode_strings'>. Under its scope, all string operations executed and
55regular expressions compiled (even if executed outside its scope) have
56Unicode semantics. See L<feature>.
5076a392 57
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58This feature avoids most forms of the "Unicode Bug" (See
59L<perlunicode/The "Unicode Bug"> for details.) If there is a
60possibility that your code will process Unicode strings, you are
61B<strongly> encouraged to use this subpragma to avoid nasty surprises.
5076a392 62
1f539a1a 63=head3 C<\N{I<name>}> and C<charnames> enhancements
5076a392 64
1f539a1a 65=over
5076a392 66
1f539a1a 67=item *
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68
69C<\N{}> and C<charnames::vianame> now know about the abbreviated
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70character names listed by Unicode, such as NBSP, SHY, LRO, ZWJ, etc., all
71the customary abbreviations for the C0 and C1 control characters (such as
72ACK, BEL, CAN, etc.), and a few new variants of some C1 full names that
73are in common usage.
5076a392 74
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75=item *
76
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77Unicode has a number of named character sequences, in which particular sequences
78of code points are given names. C<\N{...}> now recognizes these.
79
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80=item *
81
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82C<\N{}>, C<charnames::vianame>, C<charnames::viacode> now know about every
83character in Unicode. Previously, they didn't know about the Hangul syllables
84nor a number of CJK (Chinese/Japanese/Korean) characters.
85
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86=item *
87
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88In the past, it was ineffective to override one of Perl's abbreviations
89with your own custom alias. Now it works.
90
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91=item *
92
e1b1739f 93You can also create a custom alias of the ordinal of a
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94character, known by C<\N{...}>, C<charnames::vianame()>, and
95C<charnames::viacode()>. Previously, an alias had to be to an official
96Unicode character name. This made it impossible to create an alias for
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97a code point that had no name, such as those reserved for private
98use.
5076a392 99
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100=item *
101
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102A new function, C<charnames::string_vianame()>, has been added.
103This function is a run-time version of C<\N{...}>, returning the string
104of characters whose Unicode name is its parameter. It can handle
105Unicode named character sequences, whereas the pre-existing
106C<charnames::vianame()> cannot, as the latter returns a single code
107point.
108
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109=back
110
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111See L<charnames> for details on all these changes.
112
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113=head3 New warnings categories for problematic (non-)Unicode code points.
114
115Three new warnings subcategories of "utf8" have been added. These
116allow you to turn off some "utf8" warnings, while allowing
117others warnings to remain on. The three categories are:
118C<surrogate> when UTF-16 surrogates are encountered;
119C<nonchar> when Unicode non-character code points are encountered;
120and C<non_unicode> when code points that are above the legal Unicode
121maximum of 0x10FFFF are encountered.
122
1f539a1a 123=head3 Any unsigned value can be encoded as a character
5076a392 124
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125With this release, Perl is adopting a model that any unsigned value can
126be treated as a code point and encoded internally (as utf8) without
54c7bb16 127warnings - not just the code points that are legal in Unicode.
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128However, unless utf8 or the corresponding sub-category (see previous
129item) warnings have been
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130explicitly lexically turned off, outputting or performing a
131Unicode-defined operation (such as upper-casing) on such a code point
132will generate a warning. Attempting to input these using strict rules
133(such as with the C<:encoding('UTF-8')> layer) will continue to fail.
134Prior to this release the handling was very inconsistent, and incorrect
135in places. Also, the Unicode non-characters, some of which previously were
136erroneously considered illegal in places by Perl, contrary to the Unicode
137standard, are now always legal internally. But inputting or outputting
138them will work the same as for the non-legal Unicode code points, as the
139Unicode standard says they are illegal for "open interchange".
5076a392 140
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141=head3 Unicode database files not installed
142
143The Unicode database files are no longer installed with Perl. This
144doesn't affect any functionality in Perl and saves significant disk
145space. If you previously were explicitly opening and reading those
146files, you can download them from
147L<http://www.unicode.org/Public/zipped/6.0.0/>.
148
1f539a1a 149=head2 Regular Expressions
5076a392 150
1f539a1a 151=head3 C<(?^...)> construct to signify default modifiers
5076a392 152
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153An ASCII caret (also called a "circumflex accent") C<"^">
154immediately following a C<"(?"> in a regular expression
155now means that the subexpression does not inherit the
156surrounding modifiers such as C</i>, but reverts to the
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157Perl defaults. Any modifiers following the caret override the defaults.
158
159The stringification of regular expressions now uses this
160notation. E.g., before, C<qr/hlagh/i> would be stringified as
161C<(?i-xsm:hlagh)>, but now it's stringified as C<(?^i:hlagh)>.
162
163The main purpose of this is to allow tests that rely on the
e1b1739f 164stringification not to have to change when new modifiers are added.
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165See L<perlre/Extended Patterns>.
166
1f539a1a 167=head3 C</d>, C</l>, C</u>, C</a>, and C</aa> modifiers
5076a392 168
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169Four new regular expression modifiers have been added. These are mutually
170exclusive; one only can be turned on at a time.
5076a392 171
959ad7d5 172The C</l> modifier says to compile the regular expression as if it were
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173in the scope of C<use locale>, even if it is not.
174
959ad7d5 175The C</u> modifier says to compile the regular expression as if it were
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176in the scope of a C<use feature "unicode_strings"> pragma.
177
e1b1739f 178The C</d> (default) modifier is used to override any C<use locale> and
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179C<use feature "unicode_strings"> pragmas that are in effect at the time
180of compiling the regular expression.
181
959ad7d5 182The C</a> regular expression modifier restricts C<\s>, C<\d> and C<\w> and
7baaf023 183the Posix (C<[[:posix:]]>) character classes to the ASCII range. Their
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184complements and C<\b> and C<\B> are correspondingly
185affected. Otherwise, C</a> behaves like the C</u> modifier, in that
e1b1739f 186case-insensitive matching uses Unicode semantics.
5076a392 187
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188The C</aa> modifier is like C</a>, except that, in case-insensitive matching, no ASCII character will match a
189non-ASCII character. For example,
5076a392 190
959ad7d5 191 'k' =~ /\N{KELVIN SIGN}/ai
5076a392 192
959ad7d5 193will match; it won't under C</aa>.
5076a392 194
959ad7d5 195See L<perlre/Modifiers> for more detail.
5076a392 196
1f539a1a 197=head3 Non-destructive substitution
5076a392 198
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199The substitution (C<s///>) and transliteration
200(C<y///>) operators now support an C</r> option that
201copies the input variable, carries out the substitution on
202the copy and returns the result. The original remains unmodified.
5076a392 203
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204 my $old = 'cat';
205 my $new = $old =~ s/cat/dog/r;
206 # $old is 'cat' and $new is 'dog'
5076a392 207
1f539a1a 208This is particularly useful with C<map>. See L<perlop> for more examples.
5076a392 209
1f539a1a 210=head3 Reentrant regular expression engine
5076a392 211
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212It is now safe to use regular expressions within C<(?{...})> and
213C<(??{...})> code blocks inside regular expressions.
5076a392 214
1f539a1a 215These block are still experimental, however, and still have problems with
e1b1739f 216lexical (C<my>) variables and abnormal exiting.
5076a392 217
1f539a1a 218=head3 C<use re '/flags';>
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219
220The C<re> pragma now has the ability to turn on regular expression flags
221till the end of the lexical scope:
222
223 use re '/x';
224 "foo" =~ / (.+) /; # /x implied
225
226See L<re/"'/flags' mode"> for details.
227
1f539a1a 228=head3 \o{...} for octals
5076a392 229
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230There is a new octal escape sequence, C<"\o">, in double-quote-like
231contexts. This construct allows large octal ordinals beyond the
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232current max of 0777 to be represented. It also allows you to specify a
233character in octal which can safely be concatenated with other regex
234snippets and which won't be confused with being a backreference to
235a regex capture group. See L<perlre/Capture groups>.
236
237=head3 Add C<\p{Titlecase}> as a synonym for C<\p{Title}>
238
239This synonym is added for symmetry with the Unicode property names
240C<\p{Uppercase}> and C<\p{Lowercase}>.
5076a392 241
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242=head3 Regular expression debugging output improvement
243
244Regular expression debugging output (turned on by C<use re 'debug';>) now
245uses hexadecimal when escaping non-ASCII characters, instead of octal.
246
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247=head3 Return value of C<delete $+{...}>
248
249Custom regular expression engines can now determine the return value of
250C<delete> on an entry of C<%+> or C<%->.
251
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252=head2 Syntactical Enhancements
253
254=head3 Array and hash container functions accept references
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255
256All built-in functions that operate directly on array or hash
257containers now also accept hard references to arrays or hashes:
258
259 |----------------------------+---------------------------|
260 | Traditional syntax | Terse syntax |
261 |----------------------------+---------------------------|
262 | push @$arrayref, @stuff | push $arrayref, @stuff |
263 | unshift @$arrayref, @stuff | unshift $arrayref, @stuff |
264 | pop @$arrayref | pop $arrayref |
265 | shift @$arrayref | shift $arrayref |
266 | splice @$arrayref, 0, 2 | splice $arrayref, 0, 2 |
267 | keys %$hashref | keys $hashref |
268 | keys @$arrayref | keys $arrayref |
269 | values %$hashref | values $hashref |
270 | values @$arrayref | values $arrayref |
271 | ($k,$v) = each %$hashref | ($k,$v) = each $hashref |
272 | ($k,$v) = each @$arrayref | ($k,$v) = each $arrayref |
273 |----------------------------+---------------------------|
274
275This allows these built-in functions to act on long dereferencing chains
276or on the return value of subroutines without needing to wrap them in
277C<@{}> or C<%{}>:
278
279 push @{$obj->tags}, $new_tag; # old way
280 push $obj->tags, $new_tag; # new way
281
282 for ( keys %{$hoh->{genres}{artists}} ) {...} # old way
283 for ( keys $hoh->{genres}{artists} ) {...} # new way
284
285For C<push>, C<unshift> and C<splice>, the reference will auto-vivify
286if it is not defined, just as if it were wrapped with C<@{}>.
287
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288For C<keys>, C<values>, C<each>, when overloaded dereferencing is
289present, the overloaded dereference is used instead of dereferencing the
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290underlying reftype. Warnings are issued about assumptions made in
291ambiguous cases.
5076a392 292
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293=head3 Single term prototype
294
295The C<+> prototype is a special alternative to C<$> that will act like
296C<\[@%]> when given a literal array or hash variable, but will otherwise
e1b1739f 297force scalar context on the argument. See L<perlsub/Prototypes>.
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298
299=head3 C<package> block syntax
300
301A package declaration can now contain a code block, in which case the
302declaration is in scope only inside that block. So C<package Foo { ... }>
303is precisely equivalent to C<{ package Foo; ... }>. It also works with
304a version number in the declaration, as in C<package Foo 1.2 { ... }>.
e1b1739f 305See L<perlfunc>.
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306
307=head3 Statement labels can appear in more places
308
309Statement labels can now occur before any type of statement or declaration,
310such as C<package>.
311
312=head3 Stacked labels
313
314Multiple statement labels can now appear before a single statement.
315
316=head3 Uppercase X/B allowed in hexadecimal/binary literals
317
318Literals may now use either upper case C<0X...> or C<0B...> prefixes,
319in addition to the already supported C<0x...> and C<0b...>
e1b1739f 320syntax [perl #76296].
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321
322C, Ruby, Python and PHP already supported this syntax, and it makes
323Perl more internally consistent. A round-trip with C<eval sprintf
e1b1739f 324"%#X", 0x10> now returns C<16>, the way C<eval sprintf "%#x", 0x10> does.
1f539a1a 325
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326=head3 Overridable tie functions
327
328C<tie>, C<tied> and C<untie> can now be overridden [perl #75902].
329
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330=head2 Exception Handling
331
332Several changes have been made to the way C<die>, C<warn>, and C<$@>
333behave, in order to make them more reliable and consistent.
334
335When an exception is thrown inside an C<eval>, the exception is no
336longer at risk of being clobbered by code running during unwinding
337(e.g., destructors). Previously, the exception was written into C<$@>
338early in the throwing process, and would be overwritten if C<eval> was
339used internally in the destructor for an object that had to be freed
340while exiting from the outer C<eval>. Now the exception is written
341into C<$@> last thing before exiting the outer C<eval>, so the code
342running immediately thereafter can rely on the value in C<$@> correctly
343corresponding to that C<eval>. (C<$@> is still also set before exiting the
344C<eval>, for the sake of destructors that rely on this.)
345
346Likewise, a C<local $@> inside an C<eval> will no longer clobber any
347exception thrown in its scope. Previously, the restoration of C<$@> upon
348unwinding would overwrite any exception being thrown. Now the exception
349gets to the C<eval> anyway. So C<local $@> is safe before a C<die>.
350
351Exceptions thrown from object destructors no longer modify the C<$@>
352of the surrounding context. (If the surrounding context was exception
353unwinding, this used to be another way to clobber the exception being
354thrown.) Previously such an exception was
355sometimes emitted as a warning, and then either was
356string-appended to the surrounding C<$@> or completely replaced the
357surrounding C<$@>, depending on whether that exception and the surrounding
358C<$@> were strings or objects. Now, an exception in this situation is
359always emitted as a warning, leaving the surrounding C<$@> untouched.
360In addition to object destructors, this also affects any function call
361performed by XS code using the C<G_KEEPERR> flag.
362
363Warnings for C<warn> can now be objects, in the same way as exceptions
364for C<die>. If an object-based warning gets the default handling,
365of writing to standard error, it is stringified as
366before, with the file and line number appended. But
367a C<$SIG{__WARN__}> handler will now receive an
368object-based warning as an object, where previously it was passed the
369result of stringifying the object.
370
371=head2 Other Enhancements
372
373=head3 Assignment to C<$0> sets the legacy process name with C<prctl()> on Linux
374
375On Linux the legacy process name will be set with L<prctl(2)>, in
376addition to altering the POSIX name via C<argv[0]> as perl has done
377since version 4.000. Now system utilities that read the legacy process
378name such as ps, top and killall will recognize the name you set when
379assigning to C<$0>. The string you supply will be cut off at 16 bytes,
380this is a limitation imposed by Linux.
381
382=head3 C<srand()> now returns the seed
383
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384This allows programs that need to have repeatable results not to have to come
385up with their own seed-generating mechanism. Instead, they can use C<srand()>
386and stash the return value for future use. Typical is a test program which
1f539a1a 387has too many combinations to test comprehensively in the time available to it
e1b1739f 388each run. It can test a random subset each time and, should there be a failure,
1f539a1a 389log the seed used for that run so that it can later be used to reproduce the
e1b1739f 390same results.
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391
392=head3 printf-like functions understand post-1980 size modifiers
393
394Perl's printf and sprintf operators, and Perl's internal printf replacement
395function, now understand the C90 size modifiers "hh" (C<char>), "z"
396(C<size_t>), and "t" (C<ptrdiff_t>). Also, when compiled with a C99
397compiler, Perl now understands the size modifier "j" (C<intmax_t>).
398
399So, for example, on any modern machine, C<sprintf('%hhd', 257)> returns '1'.
400
401=head3 New global variable C<${^GLOBAL_PHASE}>
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402
403A new global variable, C<${^GLOBAL_PHASE}>, has been added to allow
404introspection of the current phase of the perl interpreter. It's explained in
405detail in L<perlvar/"${^GLOBAL_PHASE}"> and
406L<perlmod/"BEGIN, UNITCHECK, CHECK, INIT and END">.
407
1f539a1a 408=head3 C<-d:-foo> calls C<Devel::foo::unimport>
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409
410The syntax C<-dI<B<:>foo>> was extended in 5.6.1 to make C<-dI<:fooB<=bar>>>
411equivalent to C<-MDevel::foo=bar>, which expands
412internally to C<use Devel::foo 'bar';>.
413F<perl> now allows prefixing the module name with C<->, with the same
414semantics as C<-M>, I<i.e.>
415
416=over 4
417
418=item C<-d:-foo>
419
420Equivalent to C<-M-Devel::foo>, expands to
421C<no Devel::foo;>, calls C<< Devel::foo->unimport() >>
422if the method exists.
423
424=item C<-d:-foo=bar>
425
426Equivalent to C<-M-Devel::foo=bar>, expands to C<no Devel::foo 'bar';>,
427calls C<< Devel::foo->unimport('bar') >> if the method exists.
428
429=back
430
e1b1739f 431This is particularly useful for suppressing the default actions of a
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432C<Devel::*> module's C<import> method whilst still loading it for debugging.
433
1f539a1a 434=head3 Filehandle method calls load L<IO::File> on demand
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435
436When a method call on a filehandle would die because the method cannot
437be resolved, and L<IO::File> has not been loaded, Perl now loads L<IO::File>
438via C<require> and attempts method resolution again:
439
440 open my $fh, ">", $file;
441 $fh->binmode(":raw"); # loads IO::File and succeeds
442
443This also works for globs like STDOUT, STDERR and STDIN:
444
445 STDOUT->autoflush(1);
446
447Because this on-demand load only happens if method resolution fails, the
448legacy approach of manually loading an L<IO::File> parent class for partial
449method support still works as expected:
450
451 use IO::Handle;
452 open my $fh, ">", $file;
453 $fh->autoflush(1); # IO::File not loaded
454
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455=head3 IPv6 support
456
457The C<Socket> module provides new affordances for IPv6,
458including implementations of the C<Socket::getaddrinfo()> and
459C<Socket::getnameinfo()> functions, along with related constants, and a
460handful of new functions. See L<Socket>.
461
1f539a1a 462=head3 DTrace probes now include package name
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463
464The DTrace probes now include an additional argument (C<arg3>) which contains
465the package the subroutine being entered or left was compiled in.
466
467For example using the following DTrace script:
468
469 perl$target:::sub-entry
470 {
471 printf("%s::%s\n", copyinstr(arg0), copyinstr(arg3));
472 }
473
474and then running:
475
476 perl -e'sub test { }; test'
477
478DTrace will print:
479
480 main::test
481
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482=head2 New C APIs
483
1e463951 484See L</Internal Changes>.
9378886b 485
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486=head1 Security
487
948b8455 488=head2 User-defined regular expression properties
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489
490In L<perlunicode/"User-Defined Character Properties">, it says you can
491create custom properties by defining subroutines whose names begin with
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492"In" or "Is". However, Perl did not actually enforce that naming
493restriction, so \p{foo::bar} could call foo::bar() if it existed. Now this
494convention has been enforced.
5076a392 495
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496Also, Perl no longer allows a tainted regular expression to invoke a
497user-defined. It simply dies instead [perl #82616].
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498
499=head1 Incompatible Changes
500
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501Perl 5.14.0 is not binary-compatible with any previous stable release.
502
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503In addition to the sections that follow, see L</C API Changes>.
504
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505=head2 Regular Expressions and String Escapes
506
54c7bb16 507=head3 \400-\777
5076a392 508
54c7bb16 509Use of C<\400>-C<\777> in regexes in certain circumstances has given
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510different, anomalous behavior than their use in all other
511double-quote-like contexts. Since 5.10.1, a deprecated warning message
512has been raised when this happens. Now, all double-quote-like contexts
513have the same behavior, namely to be equivalent to C<\x{100}> -
514C<\x{1FF}>, with no deprecation warning. Use of these values in the
515command line option C<"-0"> retains the current meaning to slurp input
516files whole; previously, this was documented only for C<"-0777">. It is
517recommended, however, because of various ambiguities, to use the new
518C<\o{...}> construct to represent characters in octal.
5076a392 519
61752d82 520=head3 Most C<\p{}> properties are now immune to case-insensitive matching
5076a392 521
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522For most Unicode properties, it doesn't make sense to have them match
523differently under C</i> case-insensitive matching than not. And doing
524so leads to unexpected results and potential security holes. For
525example
5076a392 526
61752d82 527 m/\p{ASCII_Hex_Digit}+/i
5076a392 528
61752d82 529could previously match non-ASCII characters because of the Unicode
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530matching rules (although there were a number of bugs with this). Now
531matching under C</i> gives the same results as non-C</i> matching except
532for those few properties where people have come to expect differences,
533namely the ones where casing is an integral part of their meaning, such
534as C<m/\p{Uppercase}/i> and C<m/\p{Lowercase}/i>, both of which match
535the exact same code points, namely those matched by C<m/\p{Cased}/i>.
536Details are in L<perlrecharclass/Unicode Properties>.
5076a392 537
61752d82 538User-defined property handlers that need to match differently under
4cf6a51f 539C</i> must change to read the new boolean parameter passed to them which is
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540non-zero if case-insensitive matching is in effect or 0 otherwise. See
541L<perluniprops/User-Defined Character Properties>.
5076a392 542
61752d82 543=head3 \p{} implies Unicode semantics
5076a392 544
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545Now, a Unicode property match specified in the pattern will indicate
546that the pattern is meant for matching according to Unicode rules, the way
bc15a0a0 547C<\N{}> does.
5076a392 548
61752d82 549=head3 Regular expressions retain their localeness when interpolated
5076a392 550
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551Regular expressions compiled under C<"use locale"> now retain this when
552interpolated into a new regular expression compiled outside a
553C<"use locale">, and vice-versa.
5076a392 554
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555Previously, a regular expression interpolated into another one inherited
556the localeness of the surrounding one, losing whatever state it
557originally had. This is considered a bug fix, but may trip up code that
558has come to rely on the incorrect behavior.
5076a392 559
61752d82 560=head3 Stringification of regexes has changed
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561
562Default regular expression modifiers are now notated by using
563C<(?^...)>. Code relying on the old stringification will fail. The
564purpose of this is so that when new modifiers are added, such code will
565not have to change (after this one time), as the stringification will
566automatically incorporate the new modifiers.
567
568Code that needs to work properly with both old- and new-style regexes
f318e2e6 569can avoid the whole issue by using (for Perls since 5.9.5; see L<re>):
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570
571 use re qw(regexp_pattern);
572 my ($pat, $mods) = regexp_pattern($re_ref);
573
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574If the actual stringification is important, or older Perls need to be
575supported, you can use something like the following:
576
577 # Accept both old and new-style stringification
578 my $modifiers = (qr/foobar/ =~ /\Q(?^/) ? '^' : '-xism';
579
580And then use C<$modifiers> instead of C<-xism>.
581
61752d82 582=head3 Run-time code blocks in regular expressions inherit pragmata
5076a392 583
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584Code blocks in regular expressions (C<(?{...})> and C<(??{...})>) used not
585to inherit any pragmata (strict, warnings, etc.) if the regular expression
586was compiled at run time as happens in cases like these two:
5076a392 587
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588 use re 'eval';
589 $foo =~ $bar; # when $bar contains (?{...})
590 $foo =~ /$bar(?{ $finished = 1 })/;
591
592This was a bug, which has now been fixed. But it has the potential to break
593any code that was relying on it.
5076a392 594
61752d82 595=head2 Stashes and Package Variables
5076a392 596
61752d82 597=head3 Localised tied hashes and arrays are no longed tied
5076a392 598
61752d82 599In the following:
5076a392 600
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601 tie @a, ...;
602 {
603 local @a;
604 # here, @a is a now a new, untied array
605 }
606 # here, @a refers again to the old, tied array
5076a392 607
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608The new local array used to be made tied too, which was fairly pointless,
609and has now been fixed. This fix could however potentially cause a change
610in behaviour of some code.
5076a392 611
61752d82 612=head3 Stashes are now always defined
5076a392 613
61752d82
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614C<defined %Foo::> now always returns true, even when no symbols have yet been
615defined in that package.
5076a392 616
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617This is a side effect of removing a special case kludge in the tokeniser,
618added for 5.10.0, to hide side effects of changes to the internal storage of
619hashes that drastically reduce their memory usage overhead.
620
621Calling defined on a stash has been deprecated since 5.6.0, warned on
622lexicals since 5.6.0, and warned for stashes (and other package
623variables) since 5.12.0. C<defined %hash> has always exposed an
624implementation detail - emptying a hash by deleting all entries from it does
625not make C<defined %hash> false, hence C<defined %hash> is not valid code to
626determine whether an arbitrary hash is empty. Instead, use the behaviour
627that an empty C<%hash> always returns false in a scalar context.
628
629=head3 Dereferencing typeglobs
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630
631If you assign a typeglob to a scalar variable:
632
633 $glob = *foo;
634
635the glob that is copied to C<$glob> is marked with a special flag
636indicating that the glob is just a copy. This allows subsequent assignments
637to C<$glob> to overwrite the glob. The original glob, however, is
638immutable.
639
640Many Perl operators did not distinguish between these two types of globs.
641This would result in strange behaviour in edge cases: C<untie $scalar>
642would do nothing if the last thing assigned to the scalar was a glob
643(because it treated it as C<untie *$scalar>, which unties a handle).
f318e2e6 644Assignment to a glob slot (e.g., C<*$glob = \@some_array>) would simply
5076a392
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645assign C<\@some_array> to C<$glob>.
646
647To fix this, the C<*{}> operator (including the C<*foo> and C<*$foo> forms)
648has been modified to make a new immutable glob if its operand is a glob
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FC
649copy. This allows operators that make a distinction between globs and
650scalars to be modified to treat only immutable globs as globs. (C<tie>,
651C<tied> and C<untie> have been left as they are for compatibility's sake,
61752d82 652but will warn. See L</Deprecations>.)
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653
654This causes an incompatible change in code that assigns a glob to the
655return value of C<*{}> when that operator was passed a glob copy. Take the
656following code, for instance:
657
658 $glob = *foo;
659 *$glob = *bar;
660
661The C<*$glob> on the second line returns a new immutable glob. That new
662glob is made an alias to C<*bar>. Then it is discarded. So the second
663assignment has no effect.
664
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665See L<http://rt.perl.org/rt3/Public/Bug/Display.html?id=77810> for even
666more detail.
667
61752d82 668=head3 Clearing stashes
5076a392
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669
670Stash list assignment C<%foo:: = ()> used to make the stash anonymous
671temporarily while it was being emptied. Consequently, any of its
672subroutines referenced elsewhere would become anonymous (showing up as
673"(unknown)" in C<caller>). Now they retain their package names, such that
674C<caller> will return the original sub name if there is still a reference
675to its typeglob, or "foo::__ANON__" otherwise [perl #79208].
676
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677=head3 Magic variables outside the main package
678
679In previous versions of Perl, magic variables like C<$!>, C<%SIG>, etc. would
680'leak' into other packages. So C<%foo::SIG> could be used to access signals,
681C<${"foo::!"}> (with strict mode off) to access C's C<errno>, etc.
682
683This was a bug, or an 'unintentional' feature, which caused various ill effects,
684such as signal handlers being wiped when modules were loaded, etc.
685
686This has been fixed (or the feature has been removed, depending on how you see
687it).
688
689=head2 Changes to Syntax or to Perl Operators
690
691=head3 C<given> return values
692
693C<given> blocks now return the last evaluated
694expression, or an empty list if the block was exited by C<break>. Thus you
695can now write:
696
697 my $type = do {
698 given ($num) {
699 break when undef;
700 'integer' when /^[+-]?[0-9]+$/;
701 'float' when /^[+-]?[0-9]+(?:\.[0-9]+)?$/;
702 'unknown';
703 }
704 };
705
706See L<perlsyn/Return value> for details.
707
708=head3 Change in the parsing of certain prototypes
709
710Functions declared with the following prototypes now behave correctly as unary
711functions:
712
713 *
714 \$ \% \@ \* \&
715 \[...]
716 ;$ ;*
717 ;\$ ;\% etc.
718 ;\[...]
719
720Due to this bug fix [perl #75904], functions
721using the C<(*)>, C<(;$)> and C<(;*)> prototypes
722are parsed with higher precedence than before. So in the following example:
723
724 sub foo($);
725 foo $a < $b;
726
727the second line is now parsed correctly as C<< foo($a) < $b >>, rather than
728C<< foo($a < $b) >>. This happens when one of these operators is used in
729an unparenthesised argument:
730
731 < > <= >= lt gt le ge
732 == != <=> eq ne cmp ~~
733 &
734 | ^
735 &&
736 || //
737 .. ...
738 ?:
739 = += -= *= etc.
740
741=head3 Smart-matching against array slices
742
743Previously, the following code resulted in a successful match:
744
745 my @a = qw(a y0 z);
746 my @b = qw(a x0 z);
747 @a[0 .. $#b] ~~ @b;
748
749This odd behaviour has now been fixed [perl #77468].
750
751=head3 Negation treats strings differently from before
752
753The unary negation operator C<-> now treats strings that look like numbers
754as numbers [perl #57706].
755
756=head3 Negative zero
757
758Negative zero (-0.0), when converted to a string, now becomes "0" on all
759platforms. It used to become "-0" on some, but "0" on others.
760
761If you still need to determine whether a zero is negative, use
762C<sprintf("%g", $zero) =~ /^-/> or the L<Data::Float> module on CPAN.
763
764=head3 C<:=> is now a syntax error
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765
766Previously C<my $pi := 4;> was exactly equivalent to C<my $pi : = 4;>,
767with the C<:> being treated as the start of an attribute list, ending before
768the C<=>. The use of C<:=> to mean C<: => was deprecated in 5.12.0, and is now
769a syntax error. This will allow the future use of C<:=> as a new token.
770
771We find no Perl 5 code on CPAN using this construction, outside the core's
772tests for it, so we believe that this change will have very little impact on
773real-world codebases.
774
775If it is absolutely necessary to have empty attribute lists (for example,
776because of a code generator) then avoid the error by adding a space before
777the C<=>.
778
61752d82 779=head2 Threads and Processes
5076a392 780
61752d82 781=head3 Directory handles not copied to threads
5076a392 782
61752d82
FC
783On systems other than Windows that do not have
784a C<fchdir> function, newly-created threads no
785longer inherit directory handles from their parent threads. Such programs
786would usually have crashed anyway [perl #75154].
5076a392 787
61752d82 788=head3 C<close> on shared pipes
5076a392 789
61752d82
FC
790The C<close> function no longer waits for the child process to exit if the
791underlying file descriptor is still in use by another thread, to avoid
792deadlocks. It returns true in such cases.
5076a392 793
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FC
794=head3 fork() emulation will not wait for signalled children
795
796On Windows parent processes would not terminate until all forked
797childred had terminated first. However, C<kill('KILL', ...)> is
798inherently unstable on pseudo-processes, and C<kill('TERM', ...)>
799might not get delivered if the child if blocked in a system call.
800
801To avoid the deadlock and still provide a safe mechanism to terminate
802the hosting process, Perl will now no longer wait for children that
803have been sent a SIGTERM signal. It is up to the parent process to
804waitpid() for these children if child clean-up processing must be
805allowed to finish. However, it is also the responsibility of the
806parent then to avoid the deadlock by making sure the child process
807can't be blocked on I/O either.
808
809See L<perlfork> for more information about the fork() emulation on
810Windows.
811
61752d82 812=head2 Configuration
5076a392 813
61752d82 814=head3 Naming fixes in Policy_sh.SH may invalidate Policy.sh
5076a392 815
61752d82
FC
816Several long-standing typos and naming confusions in Policy_sh.SH have
817been fixed, standardizing on the variable names used in config.sh.
5076a392 818
61752d82
FC
819This will change the behavior of Policy.sh if you happen to have been
820accidentally relying on the Policy.sh incorrect behavior.
f318e2e6 821
5a1f7719
FC
822=head3 Perl source code is read in text mode on Windows
823
824Perl scripts used to be read in binary mode on Windows for the benefit
825of the ByteLoader module (which is no longer part of core Perl). This
826had the side effect of breaking various operations on the DATA filehandle,
827including seek()/tell(), and even simply reading from DATA after file handles
828have been flushed by a call to system(), backticks, fork() etc.
829
830The default build options for Windows have been changed to read Perl source
831code on Windows in text mode now. Hopefully ByteLoader will be updated on
832CPAN to automatically handle this situation [perl #28106].
833
5076a392
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834=head1 Deprecations
835
1e463951
FC
836See also L</Deprecated C APIs>.
837
5076a392
FC
838=head2 Omitting a space between a regular expression and subsequent word
839
18139a1b
FC
840Omitting a space between a regular expression operator or
841its modifiers and the following word is deprecated. For
842example, C<< m/foo/sand $bar >> will still be parsed
843as C<< m/foo/s and $bar >> but will issue a warning.
5076a392 844
e683df94
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845=head2 C<\cI<X>>
846
847The backslash-c construct was designed as a way of specifying
848non-printable characters, but there were no restrictions (on ASCII
849platforms) on what the character following the C<c> could be. Now,
850a deprecation warning is raised if that character isn't an ASCII character.
851Also, a deprecation warning is raised for C<"\c{"> (which is the same
852as simply saying C<";">).
853
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854=head2 C<"\b{"> and C<"\B{">
855
856In regular expressions, a literal C<"{"> immediately following a C<"\b">
857(not in a bracketed character class) or a C<"\B{"> is now deprecated
858to allow for its future use by Perl itself.
859
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860=head2 Deprecation warning added for deprecated-in-core .pl libs
861
862This is a mandatory warning, not obeying -X or lexical warning bits.
863The warning is modelled on that supplied by deprecate.pm for
864deprecated-in-core .pm libraries. It points to the specific CPAN
823d0e46
FC
865distribution that contains the .pl libraries. The CPAN version, of
866course, does not generate the warning.
5076a392
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867
868=head2 List assignment to C<$[>
869
823d0e46
FC
870Assignment to C<$[> was deprecated and started to give warnings in
871Perl version 5.12.0. This version of perl also starts to emit a warning when
872assigning to C<$[> in list context. This fixes an oversight in 5.12.0.
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873
874=head2 Use of qw(...) as parentheses
875
876Historically the parser fooled itself into thinking that C<qw(...)> literals
877were always enclosed in parentheses, and as a result you could sometimes omit
878parentheses around them:
879
880 for $x qw(a b c) { ... }
881
882The parser no longer lies to itself in this way. Wrap the list literal in
823d0e46 883parentheses, like this:
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884
885 for $x (qw(a b c)) { ... }
886
887=head2 C<\N{BELL}> is deprecated
888
889This is because Unicode is using that name for a different character.
890See L</Unicode Version 6.0 is now supported (mostly)> for more
891explanation.
892
893=head2 C<?PATTERN?> is deprecated
894
895C<?PATTERN?> (without the initial m) has been deprecated and now produces
896a warning. This is to allow future use of C<?> in new operators.
897The match-once functionality is still available in the form of C<m?PATTERN?>.
898
5076a392
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899=head2 Tie functions on scalars holding typeglobs
900
901Calling a tie function (C<tie>, C<tied>, C<untie>) with a scalar argument
902acts on a file handle if the scalar happens to hold a typeglob.
903
904This is a long-standing bug that will be removed in Perl 5.16, as
905there is currently no way to tie the scalar itself when it holds
906a typeglob, and no way to untie a scalar that has had a typeglob
907assigned to it.
908
823d0e46 909Now there is a deprecation warning whenever a tie
5076a392
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910function is used on a handle without an explicit C<*>.
911
18139a1b 912=head2 User-defined case-mapping
5076a392 913
18139a1b
FC
914This feature is being deprecated due to its many issues, as documented in
915L<perlunicode/User-Defined Case Mappings (for serious hackers only)>.
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916It is planned to remove this feature in Perl 5.16. Instead use the CPAN module
917L<Unicode::Casing>, which provides improved functionality.
823d0e46 918
18139a1b 919=head2 Deprecated modules
5076a392
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920
921The following modules will be removed from the core distribution in a
922future release, and should be installed from CPAN instead. Distributions
923on CPAN which require these should add them to their prerequisites. The
823d0e46 924core versions of these modules will issue a deprecation warning.
5076a392
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925
926If you ship a packaged version of Perl, either alone or as part of a
927larger system, then you should carefully consider the repercussions of
823d0e46 928core module deprecations. You may want to consider shipping your default
5076a392 929build of Perl with packages for some or all deprecated modules which
823d0e46 930install into C<vendor> or C<site> perl library directories. This will
5076a392
FC
931inhibit the deprecation warnings.
932
933Alternatively, you may want to consider patching F<lib/deprecate.pm>
934to provide deprecation warnings specific to your packaging system
935or distribution of Perl, consistent with how your packaging system
936or distribution manages a staged transition from a release where the
937installation of a single package provides the given functionality, to
938a later release where the system administrator needs to know to install
939multiple packages to get that same functionality.
940
941You can silence these deprecation warnings by installing the modules
942in question from CPAN. To install the latest version of all of them,
943just install C<Task::Deprecations::5_14>.
944
945=over
946
947=item L<Devel::DProf>
948
949We strongly recommend that you install and used L<Devel::NYTProf> in
950preference, as it offers significantly improved profiling and reporting.
951
952=back
953
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954=head1 Performance Enhancements
955
54c7bb16 956=head2 "Safe signals" optimisation
df91d470
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957
958Signal dispatch has been moved from the runloop into control ops. This
959should give a few percent speed increase, and eliminates almost all of
960the speed penalty caused by the introduction of "safe signals" in
9615.8.0. Signals should still be dispatched within the same statement as
962they were previously - if this is not the case, or it is possible to
963create uninterruptible loops, this is a bug, and reports are encouraged
964of how to recreate such issues.
965
54c7bb16 966=head2 Optimisation of shift; and pop; calls without arguments
df91d470 967
111b6aa7
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968Two fewer OPs are used for shift and pop calls with no argument (with
969implicit C<@_>). This change makes C<shift;> 5% faster than C<shift @_;>
970on non-threaded perls and 25% faster on threaded.
df91d470 971
fa232254 972=head2 Optimisation of regexp engine string comparison work
df91d470 973
fa232254
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974The foldEQ_utf8 API function for case-insensitive comparison of strings (which
975is used heavily by the regexp engine) was substantially refactored and
976optimised - and its documentation much improved as a free bonus gift.
df91d470 977
fa232254 978=head2 Regular expression compilation speed-up
df91d470 979
fa232254
FC
980Compiling regular expressions has been made faster for the case where upgrading
981the regex to utf8 is necessary but that isn't known when the compilation begins.
df91d470 982
fa232254 983=head2 String appending is 100 times faster
df91d470 984
fa232254
FC
985When doing a lot of string appending, perl could end up allocating a lot more
986memory than needed in a very inefficient way, if perl was configured to use the
987system's C<malloc> implementation instead of its own.
988
989C<sv_grow>, which is what's being used to allocate more memory if necessary
990when appending to a string, has now been taught how to round up the memory
991it requests to a certain geometric progression, making it much faster on
992certain platforms and configurations. On Win32, it's now about 100 times
993faster.
994
995=head2 Eliminate C<PL_*> accessor functions under ithreads
996
997When C<MULTIPLICITY> was first developed, and interpreter state moved into
998an interpreter struct, thread and interpreter local C<PL_*> variables were
999defined as macros that called accessor functions, returning the address of
1000the value, outside of the perl core. The intent was to allow members
1001within the interpreter struct to change size without breaking binary
1002compatibility, so that bug fixes could be merged to a maintenance branch
1003that necessitated such a size change.
1004
1005However, some non-core code defines C<PERL_CORE>, sometimes intentionally
1006to bypass this mechanism for speed reasons, sometimes for other reasons but
1007with the inadvertent side effect of bypassing this mechanism. As some of
1008this code is widespread in production use, the result is that the core
1009I<can't> change the size of members of the interpreter struct, as it will
1010break such modules compiled against a previous release on that maintenance
1011branch. The upshot is that this mechanism is redundant, and well-behaved
1012code is penalised by it. Hence it can and should be removed (and has
1013been).
1014
1015=head2 Freeing weak references
1016
1017When an object has many weak references to it, freeing that object
1018can under some some circumstances take O(N^2) time to free (where N is the
1019number of references). The number of circumstances has been reduced
1020[perl #75254]
1021
1022=head2 Lexical array and hash assignments
1023
1024An earlier optimisation to speed up C<my @array = ...> and
1025C<my %hash = ...> assignments caused a bug and was disabled in Perl 5.12.0.
1026
1027Now we have found another way to speed up these assignments [perl #82110].
df91d470 1028
111b6aa7 1029=head2 C<@_> uses less memory
df91d470 1030
111b6aa7
FC
1031Previously, C<@_> was allocated for every subroutine at compile time with
1032enough space for four entries. Now this allocation is done on demand when
1033the subroutine is called [perl #72416].
5076a392 1034
5076a392
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1035=head2 Size optimisations to SV and HV structures
1036
1037xhv_fill has been eliminated from struct xpvhv, saving 1 IV per hash and
111b6aa7 1038on some systems will cause struct xpvhv to become cache-aligned. To avoid
5076a392
FC
1039this memory saving causing a slowdown elsewhere, boolean use of HvFILL
1040now calls HvTOTALKEYS instead (which is equivalent) - so while the fill
111b6aa7
FC
1041data when actually required are now calculated on demand, the cases when
1042this needs to be done should be few and far between.
5076a392 1043
111b6aa7
FC
1044The order of structure elements in SV bodies has changed. Effectively,
1045the NV slot has swapped location with STASH and MAGIC. As all access to
1046SV members is via macros, this should be completely transparent. This
5076a392
FC
1047change allows the space saving for PVHVs documented above, and may reduce
1048the memory allocation needed for PVIVs on some architectures.
1049
fa232254
FC
1050C<XPV>, C<XPVIV>, and C<XPVNV> now only allocate the parts of the C<SV> body
1051they actually use, saving some space.
5076a392 1052
fa232254
FC
1053Scalars containing regular expressions now only allocate the part of the C<SV>
1054body they actually use, saving some space.
5076a392
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1055
1056=head2 Memory consumption improvements to Exporter
1057
1058The @EXPORT_FAIL AV is no longer created unless required, hence neither is
111b6aa7
FC
1059the typeglob backing it. This saves about 200 bytes for every package that
1060uses Exporter but doesn't use this functionality.
5076a392 1061
111b6aa7 1062=head2 Memory savings for weak references
5076a392
FC
1063
1064For weak references, the common case of just a single weak reference per
1065referent has been optimised to reduce the storage required. In this case it
111b6aa7 1066saves the equivalent of one small Perl array per referent.
5076a392 1067
111b6aa7 1068=head2 C<%+> and C<%-> use less memory
5076a392
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1069
1070The bulk of the C<Tie::Hash::NamedCapture> module used to be in the perl
111b6aa7 1071core. It has now been moved to an XS module, to reduce the overhead for
5076a392
FC
1072programs that do not use C<%+> or C<%->.
1073
fa232254 1074=head2 Multiple small improvements to threads
5076a392 1075
fa232254
FC
1076The internal structures of threading now make fewer API calls and fewer
1077allocations, resulting in noticeably smaller object code. Additionally,
1078many thread context checks have been deferred so that they're only done
1079when required (although this is only possible for non-debugging builds).
5076a392 1080
fa232254 1081=head2 Adjacent pairs of nextstate opcodes are now optimized away
5076a392 1082
fa232254 1083Previously, in code such as
5076a392 1084
fa232254 1085 use constant DEBUG => 0;
5076a392 1086
fa232254
FC
1087 sub GAK {
1088 warn if DEBUG;
1089 print "stuff\n";
1090 }
5076a392 1091
fa232254
FC
1092the ops for C<warn if DEBUG;> would be folded to a C<null> op (C<ex-const>), but
1093the C<nextstate> op would remain, resulting in a runtime op dispatch of
1094C<nextstate>, C<nextstate>, ....
5076a392 1095
fa232254
FC
1096The execution of a sequence of C<nextstate> ops is indistinguishable from just
1097the last C<nextstate> op so the peephole optimizer now eliminates the first of
1098a pair of C<nextstate> ops, except where the first carries a label, since labels
1099must not be eliminated by the optimizer and label usage isn't conclusively known
1100at compile time.
5076a392
FC
1101
1102=head1 Modules and Pragmata
1103
1104=head2 New Modules and Pragmata
1105
1106=over 4
1107
1108=item *
1109
1110C<CPAN::Meta::YAML> 0.003 has been added as a dual-life module. It supports a
1111subset of YAML sufficient for reading and writing META.yml and MYMETA.yml files
1112included with CPAN distributions or generated by the module installation
1113toolchain. It should not be used for any other general YAML parsing or
1114generation task.
1115
1116=item *
1117
1118C<CPAN::Meta> version 2.110440 has been added as a dual-life module. It
1119provides a standard library to read, interpret and write CPAN distribution
1120metadata files (e.g. META.json and META.yml) which describes a
1121distribution, its contents, and the requirements for building it and
1122installing it. The latest CPAN distribution metadata specification is
1123included as C<CPAN::Meta::Spec> and notes on changes in the specification
1124over time are given in C<CPAN::Meta::History>.
1125
1126=item *
1127
5a553547 1128C<HTTP::Tiny> 0.011 has been added as a dual-life module. It is a very
5076a392
FC
1129small, simple HTTP/1.1 client designed for simple GET requests and file
1130mirroring. It has has been added to enable CPAN.pm and CPANPLUS to
1131"bootstrap" HTTP access to CPAN using pure Perl without relying on external
1132binaries like F<curl> or F<wget>.
1133
1134=item *
1135
1136C<JSON::PP> 2.27105 has been added as a dual-life module, for the sake of
1137reading F<META.json> files in CPAN distributions.
1138
1139=item *
1140
21ef4e45 1141C<Module::Metadata> 1.000004 has been added as a dual-life module. It gathers
5076a392
FC
1142package and POD information from Perl module files. It is a standalone module
1143based on Module::Build::ModuleInfo for use by other module installation
1144toolchain components. Module::Build::ModuleInfo has been deprecated in
1145favor of this module instead.
1146
1147=item *
1148
1149C<Perl::OSType> 1.002 has been added as a dual-life module. It maps Perl
1150operating system names (e.g. 'dragonfly' or 'MSWin32') to more generic types
1151with standardized names (e.g. "Unix" or "Windows"). It has been refactored
1152out of Module::Build and ExtUtils::CBuilder and consolidates such mappings into
1153a single location for easier maintenance.
1154
1155=item *
1156
1157The following modules were added by the C<Unicode::Collate>
1158upgrade. See below for details.
1159
1160C<Unicode::Collate::CJK::Big5>
1161
1162C<Unicode::Collate::CJK::GB2312>
1163
1164C<Unicode::Collate::CJK::JISX0208>
1165
1166C<Unicode::Collate::CJK::Korean>
1167
1168C<Unicode::Collate::CJK::Pinyin>
1169
1170C<Unicode::Collate::CJK::Stroke>
1171
1172=item *
1173
1174C<Version::Requirements> version 0.101020 has been added as a dual-life
1175module. It provides a standard library to model and manipulates module
1176prerequisites and version constraints as defined in the L<CPAN::Meta::Spec>.
1177
1178=back
1179
a5794e94 1180=head2 Updated Modules and Pragma
5076a392
FC
1181
1182=over 4
1183
1184=item *
1185
81a53be2
FR
1186C<attributes> has been upgraded from version 0.12 to 0.14.
1187
1188=item *
1189
5076a392
FC
1190C<Archive::Extract> has been upgraded from version 0.38 to 0.48.
1191
1192Updates since 0.38 include: a safe print method that guards
1193Archive::Extract from changes to $\; a fix to the tests when run in core
1984204c
FC
1194perl; support for TZ files; a modification for the lzma
1195logic to favour IO::Uncompress::Unlzma; and a fix
1196for an issue with NetBSD-current and its new unzip
5076a392
FC
1197executable.
1198
1199=item *
1200
1201C<Archive::Tar> has been upgraded from version 1.54 to 1.76.
1202
1984204c
FC
1203Important changes since 1.54 include the following:
1204
1205=over
1206
1207=item *
1208
1209Compatibility with busybox implementations of tar
1210
1211=item *
1212
1213A fix so that C<write()> and C<create_archive()>
1214close only handles they opened
1215
1216=item *
1217
1218A bug was fixed regarding the exit code of extract_archive.
5076a392 1219
1984204c
FC
1220=item *
1221
4f978a3b 1222The C<ptar> utility has a new option to allow safe
5076a392
FC
1223creation of tarballs without world-writable files on Windows, allowing those
1224archives to be uploaded to CPAN.
1225
1984204c
FC
1226=item *
1227
1228A new ptargrep utility for using regular expressions against
5076a392
FC
1229the contents of files in a tar archive.
1230
1984204c
FC
1231=item *
1232
1233Pax extended headers are now skipped.
1234
1235=back
5076a392
FC
1236
1237=item *
1238
fcd5df6d
FR
1239C<Attribute::Handlers> has been upgraded from version 0.87 to 0.89.
1240
1241=item *
1242
3f5a47e4
FR
1243C<autodie> has been upgraded from version 2.06_01 to 2.1001.
1244
1245=item *
1246
578e7c9d
FR
1247C<AutoLoader> has been upgraded from version 5.70 to 5.71.
1248
1249=item *
1250
a13baafd 1251C<B> has been upgraded from version 1.23 to 1.29.
5076a392
FC
1252
1253It no longer crashes when taking apart a C<y///> containing characters
1254outside the octet range or compiled in a C<use utf8> scope.
1255
1256The size of the shared object has been reduced by about 40%, with no
1257reduction in functionality.
1258
1259=item *
1260
4a75fbf5 1261C<B::Concise> has been upgraded from version 0.78 to 0.83.
5076a392
FC
1262
1263B::Concise marks rv2sv, rv2av and rv2hv ops with the new OPpDEREF flag
1264as "DREFed".
1265
1266It no longer produces mangled output with the C<-tree> option
1267[perl #80632].
1268
1269=item *
1270
6bb8c1e3
FR
1271C<B::Debug> has been upgraded from version 1.12 to 1.16.
1272
1273=item *
1274
c67a4e29 1275C<B::Deparse> has been upgraded from version 0.96 to 1.03.
5076a392 1276
1984204c 1277The deparsing of a nextstate op has changed when it has both a
5076a392
FC
1278change of package (relative to the previous nextstate), or a change of
1279C<%^H> or other state, and a label. Previously the label was emitted
cdc10f43 1280first, but now the label is emitted last (5.12.1).
5076a392 1281
5a553547
FC
1282The C<no 5.13.2> or similar form is now correctly handled by B::Deparse
1283(5.12.3).
5076a392
FC
1284
1285B::Deparse now properly handles the code that applies a conditional
1286pattern match against implicit C<$_> as it was fixed in [perl #20444].
1287
1984204c
FC
1288Deparsing of C<our> followed by a variable with funny characters
1289(as permitted under the C<utf8> pragma) has also been fixed [perl #33752].
5076a392
FC
1290
1291=item *
1292
d97c5d3b
FR
1293C<B::Lint> has been upgraded from version 1.11_01 to 1.13.
1294
1295=item *
1296
5aef2c44
FR
1297C<base> has been upgraded from version 2.15 to 2.16.
1298
1299=item *
1300
876607aa
FR
1301C<Benchmark> has been upgraded from version 1.11 to 1.12.
1302
1303=item *
1304
e539ae69
FR
1305C<bignum> has been upgraded from version 0.23 to 0.26.
1306
1307=item *
1308
c74c1fa8 1309C<Carp> has been upgraded from version 1.15 to 1.20.
5076a392
FC
1310
1311L<Carp> now detects incomplete L<caller()|perlfunc/"caller EXPR"> overrides and
d430b8e7
FC
1312avoids using bogus C<@DB::args>. To provide backtraces,
1313Carp relies on particular behaviour of the C<caller>
1314built-in. Carp now detects if other code has
5076a392 1315overridden this with an incomplete implementation, and modifies its backtrace
d430b8e7
FC
1316accordingly. Previously incomplete overrides would cause incorrect values
1317in backtraces (best case), or obscure fatal errors (worst case).
5076a392
FC
1318
1319This fixes certain cases of C<Bizarre copy of ARRAY> caused by modules
d430b8e7 1320overriding C<caller()> incorrectly (5.12.2).
5076a392 1321
1984204c 1322It now also avoids using regular expressions that cause perl to
5076a392
FC
1323load its Unicode tables, in order to avoid the 'BEGIN not safe after
1324errors' error that will ensue if there has been a syntax error
1325[perl #82854].
1326
1327=item *
1328
9eb7ad55 1329C<CGI> has been upgraded from version 3.48 to 3.52.
5076a392
FC
1330
1331This provides the following security fixes: the MIME boundary in
1984204c
FC
1332multipart_init is now random and the handling of
1333newlines embedded in header values has been improved.
5076a392
FC
1334
1335=item *
1336
5076a392
FC
1337C<Compress::Raw::Bzip2> has been upgraded from version 2.024 to 2.033.
1338
1984204c 1339It has been updated to use bzip2 1.0.6.
5076a392
FC
1340
1341=item *
1342
51090521
FR
1343C<Compress::Raw::Zlib> has been upgraded from version 2.024 to 2.033.
1344
1345=item *
1346
f75b7efc 1347C<CPAN> has been upgraded from version 1.94_56 to 1.9600.
1984204c
FC
1348
1349Major highlights:
5076a392
FC
1350
1351=over 4
1352
1984204c 1353=item * much less configuration dialog hassle
5076a392 1354
1984204c 1355=item * support for META/MYMETA.json
5076a392 1356
1984204c 1357=item * support for local::lib
5076a392 1358
1984204c 1359=item * support for HTTP::Tiny to reduce the dependency on ftp sites
5076a392 1360
1984204c 1361=item * automatic mirror selection
5076a392 1362
1984204c 1363=item * iron out all known bugs in configure_requires
5076a392 1364
1984204c
FC
1365=item * support for distributions compressed with bzip2
1366
1367=item * allow Foo/Bar.pm on the commandline to mean Foo::Bar
1368
1369=back
5076a392
FC
1370
1371=item *
1372
d430b8e7
FC
1373C<CPANPLUS> has been upgraded from version 0.90 to 0.9103.
1374
1375A change to F<cpanp-run-perl>
1376resolves L<RT #55964|http://rt.cpan.org/Public/Bug/Display.html?id=55964>
1377and L<RT #57106|http://rt.cpan.org/Public/Bug/Display.html?id=57106>, both
1378of which related to failures to install distributions that use
1379C<Module::Install::DSL> (5.12.2).
5076a392 1380
1984204c
FC
1381A dependency on Config was not recognised as a
1382core module dependency. This has been fixed.
5076a392 1383
1984204c 1384CPANPLUS now includes support for META.json and MYMETA.json.
5076a392
FC
1385
1386=item *
1387
4467e8f7
FR
1388C<CPANPLUS::Dist::Build> has been upgraded from version 0.46 to 0.54.
1389
1390=item *
1391
5076a392
FC
1392C<Data::Dumper> has been upgraded from version 2.125 to 2.130_02.
1393
4ed2cea4
FC
1394The indentation used to be off when C<$Data::Dumper::Terse> was set. This
1395has been fixed [perl #73604].
1396
1984204c
FC
1397This upgrade also fixes a crash when using custom sort functions that might
1398cause the stack to change [perl #74170].
5076a392
FC
1399
1400C<Dumpxs> no longer crashes with globs returned by C<*$io_ref>
1401[perl #72332].
1402
1403=item *
1404
549d34f5
FR
1405C<DB_File> has been upgraded from version 1.820 to 1.821.
1406
1407=item *
1408
851dbda2
FR
1409C<DBM_Filter> has been upgraded from version 0.03 to 0.04.
1410
1411=item *
1412
5076a392
FC
1413C<Devel::DProf> has been upgraded from version 20080331.00 to 20110228.00.
1414
1415Merely loading C<Devel::DProf> now no longer triggers profiling to start.
1416C<use Devel::DProf> and C<perl -d:DProf ...> still behave as before and start
1417the profiler.
1418
1419NOTE: C<Devel::DProf> is deprecated and will be removed from a future
1984204c 1420version of Perl. We strongly recommend that you install and use
5076a392
FC
1421L<Devel::NYTProf> instead, as it offers significantly improved
1422profiling and reporting.
1423
1424=item *
1425
868625d2
FR
1426C<Devel::Peek> has been upgraded from version 1.04 to 1.07.
1427
1428=item *
1429
66899ca3
FR
1430C<Devel::SelfStubber> has been upgraded from version 1.03 to 1.05.
1431
1432=item *
1433
5076a392
FC
1434C<diagnostics> has been upgraded from version 1.19 to 1.22.
1435
1436It now renders pod links slightly better, and has been taught to find
1437descriptions for messages that share their descriptions with other
1438messages.
1439
1440=item *
1441
1442C<Digest::MD5> has been upgraded from version 2.39 to 2.51.
1443
1444It is now safe to use this module in combination with threads.
1445
1446=item *
1447
1448C<Digest::SHA> has been upgraded from version 5.47 to 5.61.
1449
1450C<shasum> now more closely mimics C<sha1sum>/C<md5sum>.
1451
1452C<Addfile> accepts all POSIX filenames.
1453
1984204c
FC
1454New SHA-512/224 and SHA-512/256 transforms (ref. NIST Draft FIPS 180-4
1455[February 2011])
5076a392
FC
1456
1457=item *
1458
e53cbaa3
FR
1459C<Dumpvalue> has been upgraded from version 1.13 to 1.16.
1460
1461=item *
1462
31e8b85a 1463C<DynaLoader> has been upgraded from version 1.10 to 1.13.
5076a392
FC
1464
1465It fixes a buffer overflow when passed a very long file name.
1466
1467It no longer inherits from AutoLoader; hence it no longer
1468produces weird error messages for unsuccessful method calls on classes that
1469inherit from DynaLoader [perl #84358].
1470
1471=item *
1472
1473C<Encode> has been upgraded from version 2.39 to 2.42.
1474
1475Now, all 66 Unicode non-characters are treated the same way U+FFFF has
1984204c
FC
1476always been treated; in cases when it was disallowed, all 66 are
1477disallowed; in those cases where it warned, all 66 warn.
5076a392
FC
1478
1479=item *
1480
68f90ac3
FR
1481C<Env> has been upgraded from version 1.01 to 1.02.
1482
1483=item *
1484
5076a392
FC
1485C<Errno> has been upgraded from version 1.11 to 1.13.
1486
1487The implementation of C<Errno> has been refactored to use about 55% less memory.
5076a392
FC
1488
1489On some platforms with unusual header files, like Win32/gcc using mingw64
1490headers, some constants which weren't actually error numbers have been exposed
1491by C<Errno>. This has been fixed [perl #77416].
1492
1493=item *
1494
1495C<Exporter> has been upgraded from version 5.64_01 to 5.64_03.
1496
1497Exporter no longer overrides C<$SIG{__WARN__}> [perl #74472]
1498
1499=item *
1500
25fe7f8f
FR
1501C<ExtUtils::CBuilder> has been upgraded from version 0.27 to 0.280202.
1502
1503=item *
1504
2292e71e
FR
1505C<ExtUtils::Command> has been upgraded from version 1.16 to 1.17.
1506
1507=item *
1508
5076a392
FC
1509C<ExtUtils::Constant> has been upgraded from 0.22 to 0.23.
1510
1511The C<AUTOLOAD> helper code generated by C<ExtUtils::Constant::ProxySubs>
1512can now C<croak> for missing constants, or generate a complete C<AUTOLOAD>
1984204c
FC
1513subroutine in XS, allowing simplification of many modules that use it
1514(C<Fcntl>, C<File::Glob>, C<GDBM_File>, C<I18N::Langinfo>, C<POSIX>,
1515C<Socket>).
5076a392
FC
1516
1517C<ExtUtils::Constant::ProxySubs> can now optionally push the names of all
1984204c 1518constants onto the package's C<@EXPORT_OK>.
5076a392
FC
1519
1520=item *
1521
588c5853
FR
1522C<ExtUtils::Install> has been upgraded from version 1.55 to 1.56.
1523
1524=item *
1525
5418ffb3
FR
1526C<ExtUtils::MakeMaker> has been upgraded from version 6.56 to 6.57_05.
1527
1528=item *
1529
f40ab45f
FR
1530C<ExtUtils::Manifest> has been upgraded from version 1.57 to 1.58.
1531
1532=item *
1533
b7064dd7
FR
1534C<ExtUtils::ParseXS> has been upgraded from version 2.21 to 2.2209.
1535
1536=item *
1537
8b87be80
FR
1538C<Fcntl> has been upgraded from version 1.06 to 1.11.
1539
1540=item *
1541
05102622
FR
1542C<File::CheckTree> has been upgraded from version 4.4 to 4.41.
1543
1544=item *
1545
e12786fa 1546C<File::DosGlob> has been upgraded from version 1.01 to 1.04.
5076a392
FC
1547
1548It allows patterns containing literal parentheses (they no longer need to
1984204c
FC
1549be escaped). On Windows, it no longer
1550adds an extra F<./> to the file names
5076a392
FC
1551returned when the pattern is a relative glob with a drive specification,
1552like F<c:*.pl> [perl #71712].
1553
1554=item *
1555
1556C<File::Fetch> has been upgraded from version 0.24 to 0.32.
1557
1558C<HTTP::Lite> is now supported for 'http' scheme.
1559
1560The C<fetch> utility is supported on FreeBSD, NetBSD and
1561Dragonfly BSD for the C<http> and C<ftp> schemes.
1562
1563=item *
1564
23f2cbb1 1565C<File::Find> has been upgraded from version 1.15 to 1.19.
5076a392 1566
1984204c 1567It improves handling of backslashes on Windows, so that paths like
5076a392
FC
1568F<c:\dir\/file> are no longer generated [perl #71710].
1569
1570=item *
1571
0ae9f678
FR
1572C<File::Glob> has been upgraded from version 1.07 to 1.12.
1573
1574=item *
1575
d430b8e7
FC
1576C<File::Spec> has been upgraded from version 3.31 to 3.33.
1577
1578Several portability fixes were made in C<File::Spec::VMS>: a colon is now
1579recognized as a delimiter in native filespecs; caret-escaped delimiters are
1580recognized for better handling of extended filespecs; C<catpath()> returns
1581an empty directory rather than the current directory if the input directory
1582name is empty; C<abs2rel()> properly handles Unix-style input (5.12.2).
1583
1584=item *
1585
46ba0657 1586C<File::stat> has been upgraded from 1.02 to 1.05.
5076a392
FC
1587
1588The C<-x> and C<-X> file test operators now work correctly under the root
1589user.
1590
1591=item *
1592
b7edcc3c
FR
1593C<Filter::Simple> has been upgraded from version 0.84 to 0.86.
1594
1595=item *
1596
dc6857fd 1597C<GDBM_File> has been upgraded from 1.10 to 1.14.
5076a392
FC
1598
1599This fixes a memory leak when DBM filters are used.
1600
1601=item *
1602
6e107b45 1603C<Hash::Util> has been upgraded from 0.07 to 0.11.
5076a392 1604
1984204c
FC
1605Hash::Util no longer emits spurious "uninitialized" warnings when
1606recursively locking hashes that have undefined values [perl #74280].
5076a392
FC
1607
1608=item *
1609
89ce9b34
FR
1610C<Hash::Util::FieldHash> has been upgraded from version 1.04 to 1.09.
1611
1612=item *
1613
eec33fe6
FR
1614C<I18N::Collate> has been upgraded from version 1.01 to 1.02.
1615
1616=item *
1617
ad5f8f47 1618C<I18N::Langinfo> has been upgraded from version 0.03 to 0.08.
5076a392
FC
1619
1620C<langinfo()> now defaults to using C<$_> if there is no argument given, just
5334145a 1621as the documentation has always claimed.
5076a392
FC
1622
1623=item *
1624
c41635f7
FR
1625C<I18N::LangTags> has been upgraded from version 0.35 to 0.35_01.
1626
1627=item *
1628
98a6a4ff
FR
1629C<if> has been upgraded from version 0.05 to 0.0601.
1630
1631=item *
1632
f6ff7fb6
FR
1633C<IO> has been upgraded from version 1.25_02 to 1.25_04.
1634
1635=item *
1636
d13528c5 1637C<IO::Select> has been upgraded from version 1.17 to 1.20.
5076a392
FC
1638
1639It now allows IO::Handle objects (and objects in derived classes) to be
1640removed from an IO::Select set even if the underlying file descriptor is
1641closed or invalid.
1642
1643=item *
1644
d07561d3 1645C<IPC::Cmd> has been upgraded from version 0.54 to 0.70.
5076a392 1646
1984204c
FC
1647Resolves an issue with splitting Win32 command lines. An argument
1648consisting of the single character "0" used to be omitted (CPAN RT #62961).
5076a392
FC
1649
1650=item *
1651
3f16e4eb 1652C<IPC::Open3> has been upgraded from 1.05 to 1.09.
5076a392 1653
4ed2cea4
FC
1654C<open3> now produces an error if the C<exec> call fails, allowing this
1655condition to be distinguished from a child process that exited with a
1656non-zero status [perl #72016].
1657
5076a392
FC
1658The internal C<xclose> routine now knows how to handle file descriptors, as
1659documented, so duplicating STDIN in a child process using its file
1660descriptor now works [perl #76474].
1661
1662=item *
1663
c8b41807
FR
1664C<IPC::SysV> has been upgraded from version 2.01 to 2.03.
1665
1666=item *
1667
ef79f038
FR
1668C<lib> has been upgraded from version 0.62 to 0.63.
1669
1670=item *
1671
5b1884f4 1672C<Locale::Maketext> has been upgraded from version 1.14 to 1.19.
5076a392 1673
1984204c 1674Locale::Maketext now supports external caches.
5076a392 1675
1984204c
FC
1676This upgrade also fixes an infinite loop in
1677C<Locale::Maketext::Guts::_compile()> when
5076a392
FC
1678working with tainted values (CPAN RT #40727).
1679
1984204c 1680C<< ->maketext >> calls will now back up and restore C<$@> so that error
5076a392
FC
1681messages are not suppressed (CPAN RT #34182).
1682
1683=item *
1684
3811bd2b
FR
1685C<Log::Message> has been upgraded from version 0.02 to 0.04.
1686
1687=item *
1688
8eb65377
FR
1689C<Log::Message::Simple> has been upgraded from version 0.06 to 0.08.
1690
1691=item *
1692
5076a392
FC
1693C<Math::BigInt> has been upgraded from version 1.89_01 to 1.994.
1694
1695This fixes, among other things, incorrect results when computing binomial
1696coefficients [perl #77640].
1697
1984204c 1698It also prevents C<sqrt($int)> from crashing under C<use bigrat;>
5076a392
FC
1699[perl #73534].
1700
1701=item *
1702
846c1cec
FR
1703C<Math::BigInt::FastCalc> has been upgraded from version 0.19 to 0.28.
1704
1705=item *
1706
fce4aef3
FR
1707C<Math::BigRat> has been upgraded from version 0.24 to 0.26_02.
1708
1709=item *
1710
12e26027
FR
1711C<Memoize> has been upgraded from version 1.01_03 to 1.02.
1712
1713=item *
1714
5076a392
FC
1715C<MIME::Base64> has been upgraded from 3.08 to 3.13.
1716
1717Includes new functions to calculate the length of encoded and decoded
1718base64 strings.
1719
1720Now provides C<encode_base64url> and C<decode_base64url> functions to process
1721the base64 scheme for "URL applications".
1722
1723=item *
1724
1725C<Module::Build> has been upgraded from version 0.3603 to 0.3800.
1726
1727A notable change is the deprecation of several modules.
1728Module::Build::Version has been deprecated and Module::Build now relies
1729directly upon L<version>. Module::Build::ModuleInfo has been deprecated in
1730favor of a standalone copy of it called L<Module::Metadata>.
1731Module::Build::YAML has been deprecated in favor of L<CPAN::Meta::YAML>.
1732
1733Module::Build now also generates META.json and MYMETA.json files
1734in accordance with version 2 of the CPAN distribution metadata specification,
1735L<CPAN::Meta::Spec>. The older format META.yml and MYMETA.yml files are
1736still generated, as well.
1737
1738=item *
1739
7259fe26 1740C<Module::CoreList> has been upgraded from version 2.29 to 2.47.
5076a392
FC
1741
1742Besides listing the updated core modules of this release, it also stops listing
1984204c 1743the C<Filespec> module. That module never existed in core. The scripts
5076a392 1744generating C<Module::CoreList> confused it with C<VMS::Filespec>, which actually
1984204c 1745is a core module as of perl 5.8.7.
5076a392
FC
1746
1747=item *
1748
193af05b
FR
1749C<Module::Load> has been upgraded from version 0.16 to 0.18.
1750
1751=item *
1752
5b3a054f
FR
1753C<Module::Load::Conditional> has been upgraded from version 0.34 to 0.44.
1754
1755=item *
1756
01835e3a
FR
1757C<mro> has been upgraded from version 1.02 to 1.07.
1758
1759=item *
1760
bfe7bf96 1761C<NDBM_File> has been upgraded from version 1.08 to 1.12.
4f978a3b
FR
1762
1763This fixes a memory leak when DBM filters are used.
1764
1765=item *
1766
d0aa5c91
FR
1767C<Net::Ping> has been upgraded from version 2.36 to 2.38.
1768
1769=item *
1770
d44b8a8c
FR
1771C<NEXT> has been upgraded from version 0.64 to 0.65.
1772
1773=item *
1774
678d4fd4
FR
1775C<Object::Accessor> has been upgraded from version 0.36 to 0.38.
1776
1777=item *
1778
34188656 1779C<ODBM_File> have been upgraded from version 1.07 to 1.10.
5076a392
FC
1780
1781This fixes a memory leak when DBM filters are used.
1782
1783=item *
1784
4c69840c
FR
1785C<Opcode> has been upgraded from version 1.15 to 1.18.
1786
1787=item *
1788
77be713d 1789C<overload> has been upgraded from 1.10 to 1.12.
5076a392
FC
1790
1791C<overload::Method> can now handle subroutines that are themselves blessed
1792into overloaded classes [perl #71998].
1793
5076a392
FC
1794The documentation has greatly improved. See L</Documentation> below.
1795
1796=item *
1797
f84c796e
FR
1798C<Params::Check> has been upgraded from version 0.26 to 0.28.
1799
1800=item *
1801
550ee92b
FR
1802C<parent> has been upgraded from version 0.223 to 0.225.
1803
1804=item *
1805
5076a392
FC
1806C<Parse::CPAN::Meta> has been upgraded from version 1.40 to 1.4401.
1807
1984204c 1808The latest Parse::CPAN::Meta can now read YAML and JSON files using
5076a392
FC
1809L<CPAN::Meta::YAML> and L<JSON::PP>, which are now part of the Perl core.
1810
1811=item *
1812
e981cf86
FR
1813C<PerlIO::encoding> has been upgraded from version 0.12 to 0.14.
1814
1815=item *
1816
5076a392
FC
1817C<PerlIO::scalar> has been upgraded from 0.07 to 0.11.
1818
1819A C<read> after a C<seek> beyond the end of the string no longer thinks it
1820has data to read [perl #78716].
1821
1822=item *
1823
776f733b
FR
1824C<PerlIO::via> has been upgraded from version 0.09 to 0.11.
1825
1826=item *
1827
ae9456cc
FR
1828C<Pod::Html> has been upgraded from version 1.09 to 1.1.
1829
1830=item *
1831
be3c8498
FR
1832C<Pod::LaTeX> has been upgraded from version 0.58 to 0.59.
1833
1834=item *
1835
fd8a2e89
FR
1836C<Pod::Perldoc> has been upgraded from version 3.15_02 to 3.15_03.
1837
1838=item *
1839
5bcb6583
FR
1840C<Pod::Simple> has been upgraded from version 3.13 to 3.16.
1841
1842=item *
1843
abb8c779 1844C<POSIX> has been upgraded from 1.19 to 1.24.
5076a392
FC
1845
1846It now includes constants for POSIX signal constants.
1847
1848=item *
1849
1984204c 1850C<re> has been upgraded from version 0.11 to 0.17.
5076a392
FC
1851
1852New C<use re "/flags"> pragma
1853
5076a392 1854The C<regmust> function used to crash when called on a regular expression
1984204c 1855belonging to a pluggable engine. Now it croaks instead.
5076a392
FC
1856
1857C<regmust> no longer leaks memory.
1858
1859=item *
1860
1861C<Safe> has been upgraded from version 2.25 to 2.29.
1862
cdc10f43
FC
1863Coderefs returned by C<reval()> and C<rdo()> are now wrapped via
1864C<wrap_code_refs> (5.12.1).
1865
5076a392
FC
1866This fixes a possible infinite loop when looking for coderefs.
1867
cdc10f43 1868It adds several version::vxs::* routines to the default share.
5076a392
FC
1869
1870=item *
1871
2c19fa42
FR
1872C<SDBM_File> has been upgraded from version 1.06 to 1.09.
1873
1874=item *
1875
5076a392
FC
1876C<SelfLoader> has been upgraded from 1.17 to 1.18.
1877
1878It now works in taint mode [perl #72062].
1879
1880=item *
1881
1882C<sigtrap> has been upgraded from version 1.04 to 1.05.
1883
1884It no longer tries to modify read-only arguments when generating a
1885backtrace [perl #72340].
1886
1887=item *
1888
1984204c 1889C<Socket> has been upgraded from version 1.87 to 1.94.
5076a392 1890
1984204c 1891See L</IPv6 support>, above.
5076a392
FC
1892
1893=item *
1894
1895C<Storable> has been upgraded from version 2.22 to 2.27.
1896
1897Includes performance improvement for overloaded classes.
1898
5076a392 1899This adds support for serialising code references that contain UTF-8 strings
1984204c
FC
1900correctly. The Storable minor version
1901number changed as a result, meaning that
5076a392
FC
1902Storable users who set C<$Storable::accept_future_minor> to a C<FALSE> value
1903will see errors (see L<Storable/FORWARD COMPATIBILITY> for more details).
1904
1905Freezing no longer gets confused if the Perl stack gets reallocated
1906during freezing [perl #80074].
1907
1908=item *
1909
648c3d7d
FR
1910C<Sys::Hostname> has been upgraded from version 1.11 to 1.16.
1911
1912=item *
1913
90c6e78f
FR
1914C<Term::ANSIColor> has been upgraded from version 2.02 to 3.00.
1915
1916=item *
1917
d9f2f059
FR
1918C<Term::UI> has been upgraded from version 0.20 to 0.26.
1919
1920=item *
1921
80ebb519
FR
1922C<Test::Harness> has been upgraded from version 3.17 to 3.23.
1923
1924=item *
1925
5076a392
FC
1926C<Test::Simple> has been upgraded from version 0.94 to 0.98.
1927
1928Among many other things, subtests without a C<plan> or C<no_plan> now have an
1929implicit C<done_testing()> added to them.
1930
1931=item *
1932
5076a392
FC
1933C<Thread::Semaphore> has been upgraded from version 2.09 to 2.12.
1934
1984204c
FC
1935It provides two new methods that give more control over the decrementing of
1936semaphores: C<down_nb> and C<down_force>.
5076a392
FC
1937
1938=item *
1939
f0d895e1
FR
1940C<Thread::Queue> has been upgraded from version 2.11 to 2.12.
1941
1942=item *
1943
1a6b954e
FR
1944C<threads> has been upgraded from version 1.75 to 1.83.
1945
1946=item *
1947
55816daa
FR
1948C<threads::shared> has been upgraded from version 1.32 to 1.36.
1949
1950=item *
1951
5076a392
FC
1952C<Tie::Hash> has been upgraded from version 1.03 to 1.04.
1953
1954Calling C<< Tie::Hash-E<gt>TIEHASH() >> used to loop forever. Now it C<croak>s.
1955
1956=item *
1957
f2adc546
FR
1958C<Tie::Hash::NamedCapture> has been upgraded from version 0.06 to 0.08.
1959
1960=item *
1961
ed68b07e
FR
1962C<Tie::RefHash> has been upgraded from version 1.38 to 1.39.
1963
1964=item *
1965
bb3c221a
FR
1966C<Time::HiRes> has been upgraded from version 1.9719 to 1.9721_01.
1967
1968=item *
1969
97fa568b
FR
1970C<Time::Local> has been upgraded from version 1.1901_01 to 1.2000.
1971
1972=item *
1973
a83cb732
FR
1974C<Time::Piece> has been upgraded from version 1.15_01 to 1.20_01.
1975
1976=item *
1977
5076a392
FC
1978C<Unicode::Collate> has been upgraded from version 0.52_01 to 0.73.
1979
1984204c 1980Unicode::Collate has been updated to use Unicode 6.0.0.
5076a392 1981
1984204c
FC
1982Unicode::Collate::Locale now supports a plethora of new locales: ar, be,
1983bg, de__phonebook, hu, hy, kk, mk, nso, om, tn, vi, hr, ig, ja, ko, ru, sq,
1984se, sr, to, uk, zh, zh__big5han, zh__gb2312han, zh__pinyin and zh__stroke.
5076a392
FC
1985
1986The following modules have been added:
1987
1988C<Unicode::Collate::CJK::Big5> for C<zh__big5han> which makes
1989tailoring of CJK Unified Ideographs in the order of CLDR's big5han ordering.
1990
1991C<Unicode::Collate::CJK::GB2312> for C<zh__gb2312han> which makes
1992tailoring of CJK Unified Ideographs in the order of CLDR's gb2312han ordering.
1993
1994C<Unicode::Collate::CJK::JISX0208> which makes tailoring of 6355 kanji
1995(CJK Unified Ideographs) in the JIS X 0208 order.
1996
1997C<Unicode::Collate::CJK::Korean> which makes tailoring of CJK Unified Ideographs
1998in the order of CLDR's Korean ordering.
1999
2000C<Unicode::Collate::CJK::Pinyin> for C<zh__pinyin> which makes
2001tailoring of CJK Unified Ideographs in the order of CLDR's pinyin ordering.
2002
2003C<Unicode::Collate::CJK::Stroke> for C<zh__stroke> which makes
2004tailoring of CJK Unified Ideographs in the order of CLDR's stroke ordering.
2005
5076a392
FC
2006This also sees the switch from using the pure-perl version of this
2007module to the XS version.
2008
2009=item *
2010
ec52b54b
FR
2011C<Unicode::Normalize> has been upgraded from version 1.03 to 1.10.
2012
2013=item *
2014
5076a392
FC
2015C<Unicode::UCD> has been upgraded from version 0.27 to 0.32.
2016
1984204c
FC
2017A new function, C<Unicode::UCD::num()>, has been added. This function
2018returns the numeric value of the string passed it or C<undef> if the string
2019in its entirety has no "safe" numeric value. (For more detail, and for the
2020definition of "safe", see L<Unicode::UCD/num>.)
5076a392 2021
1984204c 2022This upgrade also includes a number of bug fixes:
5076a392
FC
2023
2024=over 4
2025
2026=item charinfo()
2027
2028=over 4
2029
2030=item *
2031
2032It is now updated to Unicode Version 6 with Corrigendum #8, except,
2033as with Perl 5.14, the code point at U+1F514 has no name.
2034
2035=item *
2036
2037The Hangul syllable code points have the correct names, and their
2038decompositions are always output without requiring L<Lingua::KO::Hangul::Util>
2039to be installed.
2040
2041=item *
2042
54c7bb16
FC
2043The CJK (Chinese-Japanese-Korean) code points U+2A700 to U+2B734
2044and U+2B740 to U+2B81D are now properly handled.
5076a392
FC
2045
2046=item *
2047
2048The numeric values are now output for those CJK code points that have them.
2049
2050=item *
2051
2052The names that are output for code points with multiple aliases are now the
2053corrected ones.
2054
2055=back
2056
2057=item charscript()
2058
2059This now correctly returns "Unknown" instead of C<undef> for the script
2060of a code point that hasn't been assigned another one.
2061
2062=item charblock()
2063
2064This now correctly returns "No_Block" instead of C<undef> for the block
2065of a code point that hasn't been assigned to another one.
2066
2067=back
2068
5076a392
FC
2069=item *
2070
2071C<version> has been upgraded from 0.82 to 0.88.
2072
1984204c 2073Due to a bug, now fixed, the C<is_strict> and C<is_lax> functions did not
cdc10f43 2074work when exported (5.12.1).
5076a392
FC
2075
2076=item *
2077
3e625598 2078C<warnings> has been upgraded from version 1.09 to 1.12.
5076a392
FC
2079
2080Calling C<use warnings> without arguments is now significantly more efficient.
2081
4f978a3b
FR
2082=item *
2083
2084C<warnings::register> have been upgraded from version 1.01 to 1.02.
2085
5076a392
FC
2086It is now possible to register warning categories other than the names of
2087packages using C<warnings::register>. See L<perllexwarn> for more information.
2088
2089=item *
2090
62e270c2
FR
2091C<XSLoader> has been upgraded from version 0.10 to 0.13.
2092
2093=item *
2094
5076a392
FC
2095C<VMS::DCLsym> has been upgraded from version 1.03 to 1.05.
2096
2097Two bugs have been fixed [perl #84086]:
2098
2099The symbol table name was lost when tying a hash, due to a thinko in
2100C<TIEHASH>. The result was that all tied hashes interacted with the
2101local symbol table.
2102
2103Unless a symbol table name had been explicitly specified in the call
2104to the constructor, querying the special key ':LOCAL' failed to
2105identify objects connected to the local symbol table.
2106
2107=item *
2108
2109C<Win32> has been upgraded from version 0.39 to 0.44.
2110
1984204c
FC
2111This release has several new functions: C<Win32::GetSystemMetrics>,
2112C<Win32::GetProductInfo>, C<Win32::GetOSDisplayName>.
5076a392 2113
1984204c
FC
2114The names returned by C<Win32::GetOSName> and C<Win32::GetOSDisplayName>
2115have been corrected.
5076a392 2116
3bbe5383
FR
2117=item *
2118
2119C<XS::Typemap> has been upgraded from version 0.03 to 0.05.
2120
5076a392
FC
2121=back
2122
5076a392
FC
2123=head2 Removed Modules and Pragmata
2124
2125The following modules have been removed from the core distribution, and if
2126needed should be installed from CPAN instead.
2127
2128=over
2129
4f978a3b
FR
2130=item *
2131
2132C<Class::ISA> has been removed from the Perl core. Prior version was 0.36.
5076a392 2133
4f978a3b
FR
2134=item *
2135
2136C<Pod::Plainer> has been removed from the Perl core. Prior version was 1.02.
2137
2138=item *
5076a392 2139
4f978a3b 2140C<Switch> has been removed from the Perl core. Prior version was 2.16.
5076a392
FC
2141
2142=back
2143
2144The removal of C<Shell> has been deferred until after 5.14, as the
2145implementation of C<Shell> shipped with 5.12.0 did not correctly issue the
2146warning that it was to be removed from core.
2147
2148=head1 Documentation
2149
5076a392
FC
2150=head2 New Documentation
2151
41e29def 2152=head3 L<perlgpl>
5076a392
FC
2153
2154L<perlgpl> has been updated to contain GPL version 1, as is included in the
cdc10f43 2155F<README> distributed with perl (5.12.1).
5076a392 2156
41e29def 2157=head3 Perl 5.12.x delta files
5076a392 2158
41e29def
FC
2159The perldelta files for Perl 5.12.1 to 5.12.3 have been added from the
2160maintenance branch: L<perl5121delta>, L<perl5122delta>, L<perl5123delta>.
5076a392
FC
2161
2162=head3 L<perlpodstyle>
2163
2164New style guide for POD documentation,
2165split mostly from the NOTES section of the pod2man man page.
2166
41e29def
FC
2167=head3 L<perlsource>, L<perlinterp>, L<perlhacktut>, and L<perlhacktips>
2168
cc13eef1 2169See L</perlhack and perlrepository revamp>, below.
5076a392
FC
2170
2171=head2 Changes to Existing Documentation
2172
41e29def 2173=head3 L<perlmodlib> is now complete
4ed2cea4
FC
2174
2175The perlmodlib page that came with Perl 5.12.0 was missing a lot of
2176modules, due to a bug in the script that generates the list. This has been
cdc10f43 2177fixed [perl #74332] (5.12.1).
4ed2cea4 2178
41e29def 2179=head3 Replace wrong tr/// table in L<perlebcdic>
5076a392 2180
41e29def 2181L<perlebcdic> contains a helpful table to use in tr/// to convert
5076a392
FC
2182between EBCDIC and Latin1/ASCII. Unfortunately, the table was the
2183inverse of the one it describes, though the code that used the table
2184worked correctly for the specific example given.
2185
2186The table has been changed to its inverse, and the sample code changed
2187to correspond, as this is easier for the person trying to follow the
2188instructions since deriving the old table is somewhat more complicated.
2189
2190The table has also been changed to hex from octal, as that is more the norm
2191these days, and the recipes in the pod altered to print out leading
41e29def 2192zeros to make all the values the same length.
5076a392 2193
41e29def 2194=head3 Tricks for user-defined casing
5076a392 2195
41e29def
FC
2196L<perlunicode> now contains an explanation of how to override, mangle
2197and otherwise tweak the way perl handles upper-, lower- and other-case
2198conversions on Unicode data, and how to provide scoped changes to alter
2199one's own code's behaviour without stomping on anybody else.
5076a392
FC
2200
2201=head3 INSTALL explicitly states the requirement for C89
2202
d430b8e7
FC
2203This was already true but it's now Officially Stated For The Record
2204(5.12.2).
5076a392 2205
41e29def 2206=head3 Explanation of C<\xI<HH>> and C<\oI<OOO>> escapes
5076a392 2207
41e29def
FC
2208L<perlop> has been updated with more detailed explanation of these two
2209character escapes.
5076a392 2210
41e29def 2211=head3 C<-0I<NNN>> switch
5076a392 2212
41e29def 2213In L<perlrun>, the behavior of the C<-0NNN> switch for C<-0400> or higher
d430b8e7 2214has been clarified (5.12.2).
5076a392 2215
cdc10f43
FC
2216=head3 Maintenance policy
2217
2218L<perlpolicy> now contains the policy on what patches are acceptable for
2219maintenance branches (5.12.1).
2220
41e29def 2221=head3 Deprecation policy
5076a392 2222
41e29def 2223L<perlpolicy> now contains the policy on compatibility and deprecation
d430b8e7 2224along with definitions of terms like "deprecation" (5.12.2).
5076a392 2225
41e29def 2226=head3 New descriptions in L<perldiag>
5076a392
FC
2227
2228The following existing diagnostics are now documented:
2229
2230=over 4
2231
2232=item *
2233
2234L<Ambiguous use of %c resolved as operator %c|perldiag/"Ambiguous use of %c resolved as operator %c">
2235
2236=item *
2237
2238L<Ambiguous use of %c{%s} resolved to %c%s|perldiag/"Ambiguous use of %c{%s} resolved to %c%s">
2239
2240=item *
2241
2242L<Ambiguous use of %c{%s%s} resolved to %c%s%s|perldiag/"Ambiguous use of %c{%s%s} resolved to %c%s%s">
2243
2244=item *
2245
2246L<Ambiguous use of -%s resolved as -&%s()|perldiag/"Ambiguous use of -%s resolved as -&%s()">
2247
2248=item *
2249
2250L<Invalid strict version format (%s)|perldiag/"Invalid strict version format (%s)">
2251
2252=item *
2253
2254L<Invalid version format (%s)|perldiag/"Invalid version format (%s)">
2255
2256=item *
2257
2258L<Invalid version object|perldiag/"Invalid version object">
2259
2260=back
2261
5076a392
FC
2262=head3 L<perlbook>
2263
41e29def 2264L<perlbook> has been expanded to cover many more popular books.
5076a392 2265
41e29def 2266=head3 C<SvTRUE> macro
5076a392 2267
41e29def
FC
2268The documentation for the C<SvTRUE> macro in
2269L<perlapi> was simply wrong in stating that
5076a392
FC
2270get-magic is not processed. It has been corrected.
2271
41e29def 2272=head3 L<perlvar> revamp
5076a392 2273
41e29def 2274L<perlvar> reorders the variables and groups them by topic. Each variable
5076a392 2275introduced after Perl 5.000 notes the first version in which it is
41e29def 2276available. L<perlvar> also has a new section for deprecated variables to
5076a392
FC
2277note when they were removed.
2278
41e29def 2279=head3 Array and hash slices in scalar context
5076a392 2280
41e29def 2281These are now documented in L<perldata>.
5076a392 2282
41e29def 2283=head3 C<use locale> and formats
5076a392
FC
2284
2285L<perlform> and L<perllocale> have been corrected to state that
2286C<use locale> affects formats.
2287
5076a392
FC
2288=head3 L<overload>
2289
5076a392
FC
2290L<overload>'s documentation has practically undergone a rewrite. It
2291is now much more straightforward and clear.
2292
cc13eef1 2293=head3 perlhack and perlrepository revamp
5076a392
FC
2294
2295The L<perlhack> and perlrepository documents have been heavily edited and
2296split up into several new documents.
2297
2298The L<perlhack> document is now much shorter, and focuses on the Perl 5
2299development process and submitting patches to Perl. The technical content has
2300been moved to several new documents, L<perlsource>, L<perlinterp>,
2301L<perlhacktut>, and L<perlhacktips>. This technical content has only been
2302lightly edited.
2303
2304The perlrepository document has been renamed to L<perlgit>. This new document
2305is just a how-to on using git with the Perl source code. Any other content
2306that used to be in perlrepository has been moved to perlhack.
2307
41e29def 2308=head3 Time::Piece examples
5076a392
FC
2309
2310Examples in L<perlfaq4> have been updated to show the use of
41e29def 2311L<Time::Piece>.
5076a392
FC
2312
2313=head1 Diagnostics
2314
2315The following additions or changes have been made to diagnostic output,
2316including warnings and fatal error messages. For the complete list of
2317diagnostic messages, see L<perldiag>.
2318
2319=head2 New Diagnostics
2320
a593b319
FC
2321=head3 New Errors
2322
5076a392
FC
2323=over
2324
a593b319 2325=item Closure prototype called
5076a392 2326
a593b319
FC
2327This error occurs when a subroutine reference passed to an attribute
2328handler is called, if the subroutine is a closure [perl #68560].
5076a392 2329
a593b319 2330=item Insecure user-defined property %s
5076a392 2331
a593b319
FC
2332Perl detected tainted data when trying to compile a regular
2333expression that contains a call to a user-defined character property
2334function, i.e. C<\p{IsFoo}> or C<\p{InFoo}>.
2335See L<perlunicode/User-Defined Character Properties> and L<perlsec>.
5076a392 2336
a593b319 2337=item panic: gp_free failed to free glob pointer - something is repeatedly re-creating entries
5076a392 2338
a593b319
FC
2339This new error is triggered if a destructor called on an object in a
2340typeglob that is being freed creates a new typeglob entry containing an
2341object with a destructor that creates a new entry containing an object....
5076a392 2342
a593b319 2343=item Parsing code internal error (%s)
5076a392 2344
a593b319
FC
2345This new fatal error is produced when parsing
2346code supplied by an extension violates the
2347parser's API in a detectable way.
5076a392 2348
a593b319 2349=item refcnt: fd %d%s
5076a392 2350
a593b319
FC
2351This new error only occurs if a internal consistency check fails when a
2352pipe is about to be closed.
5076a392 2353
a593b319 2354=item Regexp modifier "/%c" may not appear twice
5076a392 2355
a593b319
FC
2356The regular expression pattern has one of the
2357mutually exclusive modifiers repeated.
5076a392 2358
a593b319 2359=item Regexp modifiers "/%c" and "/%c" are mutually exclusive
5076a392 2360
a593b319
FC
2361The regular expression pattern has more than one of the mutually
2362exclusive modifiers.
5076a392 2363
a593b319 2364=item Using !~ with %s doesn't make sense
5076a392 2365
a593b319 2366This error occurs when C<!~> is used with C<s///r> or C<y///r>.
5076a392 2367
a593b319 2368=back
5076a392 2369
a593b319 2370=head3 New Warnings
5076a392 2371
a593b319 2372=over
5076a392 2373
a593b319 2374=item "\b{" is deprecated; use "\b\{" instead
5076a392 2375
a593b319 2376=item "\B{" is deprecated; use "\B\{" instead
5076a392 2377
a593b319
FC
2378Use of an unescaped "{" immediately following a C<\b> or C<\B> is now
2379deprecated so as to reserve its use for Perl itself in a future release.
5076a392 2380
a593b319 2381=item Operation "%s" returns its argument for ...
5076a392 2382
a593b319
FC
2383Performing an operation requiring Unicode semantics (such as case-folding)
2384on a Unicode surrogate or a non-Unicode character now triggers a warning:
2385'Operation "%s" returns its argument for ...'.
5076a392 2386
a593b319
FC
2387=item Use of qw(...) as parentheses is deprecated
2388
2389See L</"Use of qw(...) as parentheses">, above, for details.
5076a392
FC
2390
2391=back
2392
2393=head2 Changes to Existing Diagnostics
2394
2395=over 4
2396
2397=item *
2398
4ed2cea4
FC
2399The "Variable $foo is not imported" warning that precedes a
2400C<strict 'vars'> error has now been assigned the "misc" category, so that
2401C<no warnings> will suppress it [perl #73712].
2402
2403=item *
2404
5076a392
FC
2405C<warn> and C<die> now produce 'Wide character' warnings when fed a
2406character outside the byte range if STDERR is a byte-sized handle.
2407
2408=item *
2409
2410The 'Layer does not match this perl' error message has been replaced with
a593b319 2411these more helpful messages [perl #73754]:
5076a392
FC
2412
2413=over 4
2414
2415=item *
2416
2417PerlIO layer function table size (%d) does not match size expected by this
2418perl (%d)
2419
2420=item *
2421
2422PerlIO layer instance size (%d) does not match size expected by this perl
2423(%d)
2424
2425=back
2426
5076a392
FC
2427=item *
2428
2429The "Found = in conditional" warning that is emitted when a constant is
2430assigned to a variable in a condition is now withheld if the constant is
2431actually a subroutine or one generated by C<use constant>, since the value
2432of the constant may not be known at the time the program is written
2433[perl #77762].
2434
2435=item *
2436
2437Previously, if none of the C<gethostbyaddr>, C<gethostbyname> and
2438C<gethostent> functions were implemented on a given platform, they would
2439all die with the message 'Unsupported socket function "gethostent" called',
2440with analogous messages for C<getnet*> and C<getserv*>. This has been
2441corrected.
2442
2443=item *
2444
a593b319
FC
2445The warning message about unrecognized regular expression escapes passed
2446through has been changed to include any literal '{' following the
2447two-character escape. E.g., "\q{" is now emitted instead of "\q".
5076a392
FC
2448
2449=back
2450
2451=head1 Utility Changes
2452
0b88cc74 2453=head3 L<perlbug>
5076a392
FC
2454
2455=over 4
2456
2457=item *
2458
0b88cc74
FC
2459L<perlbug> now looks in the EMAIL environment variable for a return address
2460if the REPLY-TO and REPLYTO variables are empty.
5076a392
FC
2461
2462=item *
2463
0b88cc74
FC
2464L<perlbug> did not previously generate a From: header, potentially
2465resulting in dropped mail. Now it does include that header.
5076a392
FC
2466
2467=item *
2468
0b88cc74 2469The user's address is now used as the return-path.
4ed2cea4 2470
0b88cc74
FC
2471Many systems these days don't have a valid Internet domain name and
2472perlbug@perl.org does not accept email with a return-path that does
2473not resolve. So the user's address is now passed to sendmail so it's
2474less likely to get stuck in a mail queue somewhere [perl #82996].
5076a392 2475
2c389f6c
FC
2476=item *
2477
d430b8e7
FC
2478L<perlbug> now always gives the reporter a chance to change the email
2479address it guesses for them (5.12.2).
2480
2481=item *
2482
2483L<perlbug> should no longer warn about uninitialized values when using the C<-d>
2484and C<-v> options (5.12.2).
2c389f6c 2485
5076a392
FC
2486=back
2487
0b88cc74 2488=head3 L<perl5db.pl>
5076a392 2489
0b88cc74 2490=over
5076a392
FC
2491
2492=item *
2493
0b88cc74
FC
2494The remote terminal works after forking and spawns new sessions - one
2495for each forked process.
5076a392
FC
2496
2497=back
2498
0b88cc74 2499=head3 L<ptargrep>
5076a392
FC
2500
2501=over 4
2502
2503=item *
2504
0b88cc74
FC
2505L<ptargrep> is a new utility to apply pattern matching to the contents of
2506files in a tar archive. It comes with C<Archive::Tar>.
5076a392
FC
2507
2508=back
2509
2510=head1 Configuration and Compilation
2511
61752d82
FC
2512See also L</"Naming fixes in Policy_sh.SH may invalidate Policy.sh">,
2513above.
2514
5076a392
FC
2515=over 4
2516
2517=item *
2518
87595b22
FC
2519CCINCDIR and CCLIBDIR for the mingw64
2520cross-compiler are now correctly under
5076a392
FC
2521$(CCHOME)\mingw\include and \lib rather than immediately below $(CCHOME).
2522
5076a392
FC
2523This means the 'incpath', 'libpth', 'ldflags', 'lddlflags' and
2524'ldflags_nolargefiles' values in Config.pm and Config_heavy.pl are now
87595b22 2525set correctly.
5076a392
FC
2526
2527=item *
2528
87595b22
FC
2529'make test.valgrind' has been adjusted to account for cpan/dist/ext
2530separation.
5076a392
FC
2531
2532=item *
2533
2534On compilers that support it, C<-Wwrite-strings> is now added to cflags by
2535default.
2536
2537=item *
2538
2539The C<Encode> module can now (once again) be included in a static Perl
2540build. The special-case handling for this situation got broken in Perl
25415.11.0, and has now been repaired.
2542
1e463951
FC
2543=item *
2544
2545The previous default size of a PerlIO buffer (4096 bytes) has been increased
2546to the larger of 8192 bytes and your local BUFSIZ. Benchmarks show that doubling
2547this decade-old default increases read and write performance in the neighborhood
2548of 25% to 50% when using the default layers of perlio on top of unix. To choose
2549a non-default size, such as to get back the old value or to obtain an even
2550larger value, configure with:
2551
2552 ./Configure -Accflags=-DPERLIOBUF_DEFAULT_BUFSIZ=N
2553
2554where N is the desired size in bytes; it should probably be a multiple of
2555your page size.
2556
d430b8e7
FC
2557=item *
2558
2559An "incompatible operand types" error in ternary expressions when building
2560with C<clang> has been fixed (5.12.2).
2561
2562=item *
2563
2564Perl now skips setuid C<File::Copy> tests on partitions it detects to be mounted
2565as C<nosuid> (5.12.2).
2566
5076a392
FC
2567=back
2568
5076a392
FC
2569=head1 Platform Support
2570
5076a392
FC
2571=head2 New Platforms
2572
5076a392
FC
2573=over 4
2574
2575=item AIX
2576
cdc10f43 2577Perl now builds on AIX 4.2 (5.12.1).
5076a392
FC
2578
2579=back
2580
2581=head2 Discontinued Platforms
2582
2583=over 4
2584
5076a392
FC
2585=item Apollo DomainOS
2586
2587The last vestiges of support for this platform have been excised from the
2588Perl distribution. It was officially discontinued in version 5.12.0. It had
2589not worked for years before that.
2590
2591=item MacOS Classic
2592
2593The last vestiges of support for this platform have been excised from the
2594Perl distribution. It was officially discontinued in an earlier version.
2595
2596=back
2597
2598=head2 Platform-Specific Notes
2599
d430b8e7
FC
2600=head3 AIX
2601
2602=over
2603
2604=item *
2605
2606F<README.aix> has been updated with information about the XL C/C++ V11 compiler
2607suite (5.12.2).
2608
2609=back
2610
2611=head3 ARM
2612
2613=over
2614
2615=item *
2616
2617The C<d_u32align> configuration probe on ARM has been fixed (5.12.2).
2618
2619=back
2620
554003a2 2621=head3 Cygwin
5076a392
FC
2622
2623=over 4
2624
2625=item *
2626
554003a2 2627MakeMaker has been updated to build man pages on cygwin.
5076a392
FC
2628
2629=item *
2630
554003a2
FC
2631Improved rebase behaviour
2632
2633If a dll is updated on cygwin the old imagebase address is reused.
2634This solves most rebase errors, especially when updating on core dll's.
2635See L<http://www.tishler.net/jason/software/rebase/rebase-2.4.2.README> for more information.
5076a392
FC
2636
2637=item *
2638
554003a2 2639Support for the standard cygwin dll prefix, which is e.g. needed for FFI's
5076a392
FC
2640
2641=item *
2642
554003a2 2643Updated build hints file
5076a392
FC
2644
2645=back
2646
cdc10f43
FC
2647=head3 FreeBSD 7
2648
2649=over
2650
2651=item *
2652
2653FreeBSD 7 no longer contains F</usr/bin/objformat>. At build time,
2654Perl now skips the F<objformat> check for versions 7 and higher and
2655assumes ELF (5.12.1).
2656
2657=back
2658
2659=head3 HP-UX
2660
2661=over
2662
2663=item *
2664
2665Perl now allows -Duse64bitint without promoting to use64bitall on HP-UX
2666(5.12.1).
2667
2668=back
2669
554003a2 2670=head3 IRIX
5076a392
FC
2671
2672Conversion of strings to floating-point numbers is now more accurate on
2673IRIX systems [perl #32380].
2674
554003a2 2675=head3 Mac OS X
5076a392
FC
2676
2677Early versions of Mac OS X (Darwin) had buggy implementations of the
2678C<setregid>, C<setreuid>, C<setrgid> and C<setruid> functions, so perl
2679would pretend they did not exist.
2680
2681These functions are now recognised on Mac OS 10.5 (Leopard; Darwin 9) and
2682higher, as they have been fixed [perl #72990].
2683
554003a2 2684=head3 MirBSD
5076a392 2685
554003a2
FC
2686Previously if you built perl with a shared libperl.so on MirBSD (the
2687default config), it would work up to the installation; however, once
2688installed, it would be unable to find libperl. So path handling is now
2689treated as in the other BSD dialects.
5076a392 2690
554003a2 2691=head3 NetBSD
5076a392 2692
554003a2
FC
2693The NetBSD hints file has been changed to make the system's malloc the
2694default.
5076a392 2695
554003a2 2696=head3 Recent OpenBSDs now use perl's malloc
5076a392 2697
554003a2
FC
2698OpenBSD E<gt> 3.7 has a new malloc implementation which is mmap-based
2699and as such can release memory back to the OS; however, perl's use of
2700this malloc causes a substantial slowdown so we now default to using
2701perl's malloc instead [perl #75742].
5076a392 2702
554003a2 2703=head3 OpenVOS
5076a392 2704
554003a2 2705perl now builds again with OpenVOS (formerly known as Stratus VOS)
5a553547 2706[perl #78132] (5.12.3).
5076a392 2707
554003a2 2708=head3 Solaris
5076a392 2709
554003a2 2710DTrace is now supported on Solaris. There used to be build failures, but
5a553547 2711these have been fixed [perl #73630] (5.12.3).
5076a392 2712
554003a2 2713=head3 VMS
5076a392
FC
2714
2715=over
2716
2717=item *
2718
cdc10f43
FC
2719It's now possible to build extensions on older (pre 7.3-2) VMS systems.
2720
2721DCL symbol length was limited to 1K up until about seven years or
2722so ago, but there was no particularly deep reason to prevent those
2723older systems from configuring and building Perl (5.12.1).
2724
2725=item *
2726
2727We fixed the previously-broken C<-Uuseperlio> build on VMS.
2728
2729We were checking a variable that doesn't exist in the non-default
2730case of disabling perlio. Now we only look at it when it exists (5.12.1).
2731
2732=item *
2733
2734We fixed the -Uuseperlio command-line option in configure.com.
2735
2736Formerly it only worked if you went through all the questions
2737interactively and explicitly answered no (5.12.1).
2738
2739=item *
2740
554003a2 2741C<PerlIOUnix_open> now honours the default permissions on VMS.
5076a392 2742
554003a2
FC
2743When C<perlio> became the default and C<unixio> became the default bottom layer,
2744the most common path for creating files from Perl became C<PerlIOUnix_open>,
2745which has always explicitly used C<0666> as the permission mask.
5076a392 2746
554003a2
FC
2747To avoid this, C<0777> is now passed as the permissions to C<open()>. In the
2748VMS CRTL, C<0777> has a special meaning over and above intersecting with the
2749current umask; specifically, it allows Unix syscalls to preserve native default
5a553547
FC
2750permissions (5.12.3).
2751
2752=item *
2753
2754Spurious record boundaries are no longer
2755introduced by the PerlIO layer during output (5.12.3).
5076a392
FC
2756
2757=item *
2758
554003a2
FC
2759The shortening of symbols longer than 31 characters in the C sources is
2760now done by the compiler rather than by xsubpp (which could only do so
2761for generated symbols in XS code).
5076a392
FC
2762
2763=item *
2764
554003a2
FC
2765Record-oriented files (record format variable or variable with fixed control)
2766opened for write by the perlio layer will now be line-buffered to prevent the
2767introduction of spurious line breaks whenever the perlio buffer fills up.
5076a392 2768
d430b8e7
FC
2769=item *
2770
2771F<git_version.h> is now installed on VMS. This was an oversight in v5.12.0 which
2772caused some extensions to fail to build (5.12.2).
2773
2774=item *
2775
2776Several memory leaks in L<stat()|perlfunc/"stat FILEHANDLE"> have been fixed (5.12.2).
2777
2778=item *
2779
2780A memory leak in C<Perl_rename()> due to a double allocation has been
2781fixed (5.12.2).
2782
2783=item *
2784
2785A memory leak in C<vms_fid_to_name()> (used by C<realpath()> and
2786C<realname()>) has been fixed (5.12.2).
2787
5076a392
FC
2788=back
2789
554003a2 2790=head3 Windows
5076a392 2791
5a1f7719
FC
2792See also L</"fork() emulation will not wait for signalled children"> and
2793L</"Perl source code is read in text mode on Windows">, above.
2794
5076a392
FC
2795=over 4
2796
2797=item *
2798
554003a2 2799Fixed build process for SDK2003SP1 compilers.
5076a392 2800
554003a2 2801=item *
5076a392 2802
01b1a9e4
FC
2803Compilation with Visual Studio 2010 is now supported.
2804
2805=item *
2806
554003a2
FC
2807When using old 32-bit compilers, the define C<_USE_32BIT_TIME_T> will now
2808be set in C<$Config{ccflags}>. This improves portability when compiling
2809XS extensions using new compilers, but for a perl compiled with old 32-bit
2810compilers.
5076a392
FC
2811
2812=item *
2813
554003a2
FC
2814C<$Config{gccversion}> is now set correctly when perl is built using the
2815mingw64 compiler from L<http://mingw64.org> [perl #73754].
5076a392 2816
554003a2
FC
2817=item *
2818
d430b8e7
FC
2819When building Perl with the mingw64 x64 cross-compiler C<incpath>,
2820C<libpth>, C<ldflags>, C<lddlflags> and C<ldflags_nolargefiles> values
2821in F<Config.pm> and F<Config_heavy.pl> were not previously being set
2822correctly because, with that compiler, the include and lib directories
2823are not immediately below C<$(CCHOME)> (5.12.2).
2824
2825=item *
2826
554003a2
FC
2827The build process proceeds more smoothly with mingw and dmake when
2828F<C:\MSYS\bin> is in the PATH, due to a C<Cwd> fix.
5076a392
FC
2829
2830=item *
2831
554003a2
FC
2832Support for building with Visual C++ 2010 is now underway, but is not yet
2833complete. See F<README.win32> or L<perlwin32> for more details.
5076a392 2834
554003a2
FC
2835=item *
2836
2837The option to use an externally-supplied C<crypt()>, or to build with no
2838C<crypt()> at all, has been removed. Perl supplies its own C<crypt()>
2839implementation for Windows, and the political situation that required
2840this part of the distribution to sometimes be omitted is long gone.
5076a392
FC
2841
2842=back
2843
2844=head1 Internal Changes
2845
1e463951 2846=head2 New APIs
5076a392 2847
1e463951 2848=head3 CLONE_PARAMS structure added to ease correct thread creation
5076a392 2849
1e463951
FC
2850Modules that create threads should now create C<CLONE_PARAMS> structures
2851by calling the new function C<Perl_clone_params_new()>, and free them with
2852C<Perl_clone_params_del()>. This will ensure compatibility with any future
2853changes to the internals of the C<CLONE_PARAMS> structure layout, and that
2854it is correctly allocated and initialised.
5076a392 2855
1e463951 2856=head3 New parsing functions
5076a392 2857
1e463951
FC
2858Several functions have been added for parsing statements or multiple
2859statements:
5076a392 2860
1e463951 2861=over
5076a392
FC
2862
2863=item *
2864
1e463951 2865C<parse_fullstmt> parses a complete Perl statement.
5076a392
FC
2866
2867=item *
2868
1e463951
FC
2869C<parse_stmtseq> parses a sequence of statements, up
2870to closing brace or EOF.
5076a392
FC
2871
2872=item *
2873
1e463951 2874C<parse_block> parses a block [perl #78222].
5076a392
FC
2875
2876=item *
2877
1e463951
FC
2878C<parse_barestmt> parses a statement
2879without a label.
5076a392
FC
2880
2881=item *
2882
1e463951 2883C<parse_label> parses a statement label, separate from statements.
5076a392 2884
1e463951 2885=back
5076a392 2886
1e463951
FC
2887The
2888L<C<parse_fullexpr()>|perlapi/parse_fullexpr>,
2889L<C<parse_listexpr()>|perlapi/parse_listexpr>,
2890L<C<parse_termexpr()>|perlapi/parse_termexpr>, and
2891L<C<parse_arithexpr()>|perlapi/parse_arithexpr>
2892functions have been added to the API. They perform
2893recursive-descent parsing of expressions at various precedence levels.
2894They are expected to be used by syntax plugins.
5076a392 2895
1e463951 2896See L<perlapi> for details.
5076a392 2897
1e463951 2898=head3 Hints hash API
5076a392 2899
1e463951
FC
2900A new C API for introspecting the hinthash C<%^H> at runtime has been
2901added. See C<cop_hints_2hv>, C<cop_hints_fetchpvn>, C<cop_hints_fetchpvs>,
2902C<cop_hints_fetchsv>, and C<hv_copy_hints_hv> in L<perlapi> for details.
5076a392 2903
1e463951
FC
2904A new, experimental API has been added for accessing the internal
2905structure that Perl uses for C<%^H>. See the functions beginning with
2906C<cophh_> in L<perlapi>.
5076a392 2907
1e463951 2908=head3 C interface to C<caller()>
5076a392 2909
1e463951
FC
2910The C<caller_cx> function has been added as an XSUB-writer's equivalent of
2911C<caller()>. See L<perlapi> for details.
5076a392 2912
1e463951 2913=head3 Custom per-subroutine check hooks
5076a392 2914
1e463951
FC
2915XS code in an extension module can now annotate a subroutine (whether
2916implemented in XS or in Perl) so that nominated XS code will be called
2917at compile time (specifically as part of op checking) to change the op
2918tree of that subroutine. The compile-time check function (supplied by
2919the extension module) can implement argument processing that can't be
2920expressed as a prototype, generate customised compile-time warnings,
2921perform constant folding for a pure function, inline a subroutine
2922consisting of sufficiently simple ops, replace the whole call with a
2923custom op, and so on. This was previously all possible by hooking the
2924C<entersub> op checker, but the new mechanism makes it easy to tie the
2925hook to a specific subroutine. See L<perlapi/cv_set_call_checker>.
5076a392 2926
1e463951
FC
2927To help in writing custom check hooks, several subtasks within standard
2928C<entersub> op checking have been separated out and exposed in the API.
5076a392 2929
1e463951 2930=head3 Improved support for custom OPs
5076a392 2931
1e463951
FC
2932Custom ops can now be registered with the new C<custom_op_register> C
2933function and the C<XOP> structure. This will make it easier to add new
2934properties of custom ops in the future. Two new properties have been added
2935already, C<xop_class> and C<xop_peep>.
5076a392 2936
1e463951
FC
2937C<xop_class> is one of the OA_*OP constants, and allows L<B> and other
2938introspection mechanisms to work with custom ops
2939that aren't BASEOPs. C<xop_peep> is a pointer to
2940a function that will be called for ops of this
2941type from C<Perl_rpeep>.
5076a392 2942
1e463951
FC
2943See L<perlguts/Custom Operators> and L<perlapi/Custom Operators> for more
2944detail.
5076a392 2945
1e463951
FC
2946The old C<PL_custom_op_names>/C<PL_custom_op_descs> interface is still
2947supported but discouraged.
5076a392 2948
1e463951 2949=head3 Scope hooks
5076a392 2950
1e463951
FC
2951It is now possible for XS code to hook into Perl's lexical scope
2952mechanism at compile time, using the new C<Perl_blockhook_register>
2953function. See L<perlguts/"Compile-time scope hooks">.
5076a392 2954
1e463951 2955=head3 The recursive part of the peephole optimizer is now hookable
5076a392
FC
2956
2957In addition to C<PL_peepp>, for hooking into the toplevel peephole optimizer, a
2958C<PL_rpeepp> is now available to hook into the optimizer recursing into
2959side-chains of the optree.
2960
1e463951 2961=head3 New non-magical variants of existing functions
5076a392 2962
1e463951
FC
2963The following functions/macros have been added to the API. The C<*_nomg>
2964macros are equivalent to their non-_nomg variants, except that they ignore
2965get-magic. Those ending in C<_flags> allow one to specify whether
2966get-magic is processed.
5076a392 2967
1e463951
FC
2968 sv_2bool_flags
2969 SvTRUE_nomg
2970 sv_2nv_flags
2971 SvNV_nomg
2972 sv_cmp_flags
2973 sv_cmp_locale_flags
2974 sv_eq_flags
2975 sv_collxfrm_flags
5076a392 2976
1e463951 2977In some of these cases, the non-_flags functions have
5076a392
FC
2978been replaced with wrappers around the new functions.
2979
1e463951 2980=head3 pv/pvs/sv versions of existing functions
5076a392 2981
1e463951 2982Many functions ending with pvn now have equivalent pv/pvs/sv versions.
5076a392 2983
1e463951 2984=head3 List op-building functions
5076a392 2985
1e463951
FC
2986List op-building functions have been added to the
2987API. See L<op_append_elem|perlapi/op_append_elem>,
2988L<op_append_list|perlapi/op_append_list>, and
2989L<op_prepend_elem|perlapi/op_prepend_elem> in L<perlapi>.
5076a392 2990
1e463951 2991=head3 C<LINKLIST>
5076a392 2992
1e463951
FC
2993The L<LINKLIST|perlapi/LINKLIST> macro, part of op building that
2994constructs the execution-order op chain, has been added to the API.
5076a392 2995
1e463951 2996=head3 Localisation functions
5076a392 2997
1e463951
FC
2998The C<save_freeop>, C<save_op>, C<save_pushi32ptr> and C<save_pushptrptr>
2999functions have been added to the API.
5076a392 3000
1e463951 3001=head3 Stash names
5076a392 3002
1e463951
FC
3003A stash can now have a list of effective names in addition to its usual
3004name. The first effective name can be accessed via the C<HvENAME> macro,
3005which is now the recommended name to use in MRO linearisations (C<HvNAME>
3006being a fallback if there is no C<HvENAME>).
5076a392 3007
1e463951
FC
3008These names are added and deleted via C<hv_ename_add> and
3009C<hv_ename_delete>. These two functions are I<not> part of the API.
5076a392 3010
1e463951 3011=head3 New functions for finding and removing magic
5076a392 3012
1e463951
FC
3013The L<C<mg_findext()>|perlapi/mg_findext> and
3014L<C<sv_unmagicext()>|perlapi/sv_unmagicext>
3015functions have been added to the API.
3016They allow extension authors to find and remove magic attached to
3017scalars based on both the magic type and the magic virtual table, similar to how
3018C<sv_magicext()> attaches magic of a certain type and with a given virtual table
3019to a scalar. This eliminates the need for extensions to walk the list of
3020C<MAGIC> pointers of an C<SV> to find the magic that belongs to them.
5076a392 3021
1e463951 3022=head3 C<find_rundefsv>
5076a392 3023
1e463951
FC
3024This function returns the SV representing C<$_>, whether it's lexical
3025or dynamic.
5076a392 3026
1e463951 3027=head3 C<Perl_croak_no_modify>
5076a392 3028
1e463951
FC
3029C<Perl_croak_no_modify()> is short-hand for
3030C<Perl_croak("%s", PL_no_modify)>.
5076a392 3031
1e463951 3032=head3 C<PERL_STATIC_INLINE> define
5076a392 3033
1e463951
FC
3034The C<PERL_STATIC_INLINE> define has been added to provide the best-guess
3035incantation to use for static inline functions, if the C compiler supports
3036C99-style static inline. If it doesn't, it'll give a plain C<static>.
5076a392 3037
1e463951
FC
3038C<HAS_STATIC_INLINE> can be used to check if the compiler actually supports
3039inline functions.
5076a392 3040
1e463951 3041=head3 New C<pv_escape> option for hexadecimal escapes
5076a392 3042
1e463951
FC
3043A new option, C<PERL_PV_ESCAPE_NONASCII>, has been added to C<pv_escape> to
3044dump all characters above ASCII in hexadecimal. Before, one could get all
3045characters as hexadecimal or the Latin1 non-ASCII as octal.
5076a392 3046
1e463951 3047=head3 C<lex_start>
5076a392 3048
1e463951 3049C<lex_start> has been added to the API, but is considered experimental.
5076a392 3050
1e463951 3051=head3 C<op_scope()> and C<op_lvalue()>
5076a392 3052
1e463951
FC
3053The C<op_scope()> and C<op_lvalue()> functions have been added to the API,
3054but are considered experimental.
5076a392 3055
1e463951 3056=head2 C API Changes
5076a392 3057
1e463951 3058=head3 C<PERL_POLLUTE> has been removed
5076a392 3059
1e463951
FC
3060The option to define C<PERL_POLLUTE> to expose older 5.005 symbols for
3061backwards compatibility has been removed. It's use was always discouraged,
3062and MakeMaker contains a more specific escape hatch:
5076a392 3063
1e463951 3064 perl Makefile.PL POLLUTE=1
5076a392 3065
1e463951
FC
3066This can be used for modules that have not been upgraded to 5.6 naming
3067conventions (and really should be completely obsolete by now).
5076a392 3068
1e463951 3069=head3 Check API compatibility when loading XS modules
5076a392 3070
1e463951
FC
3071When perl's API changes in incompatible ways (which usually happens between
3072major releases), XS modules compiled for previous versions of perl will not
3073work anymore. They will need to be recompiled against the new perl.
5076a392 3074
1e463951
FC
3075In order to ensure that modules are recompiled, and to prevent users from
3076accidentally loading modules compiled for old perls into newer ones, the
3077C<XS_APIVERSION_BOOTCHECK> macro has been added. That macro, which is
3078called when loading every newly compiled extension, compares the API
3079version of the running perl with the version a module has been compiled for
3080and raises an exception if they don't match.
5076a392 3081
1e463951 3082=head3 Perl_fetch_cop_label
5076a392 3083
1e463951
FC
3084The first argument of the C API function C<Perl_fetch_cop_label> has changed
3085from C<struct refcounted he *> to C<COP *>, to insulate the user from
3086implementation details.
5076a392 3087
1e463951
FC
3088This API function was marked as "may change", and likely isn't in use outside
3089the core. (Neither an unpacked CPAN, nor Google's codesearch, finds any other
3090references to it.)
5076a392 3091
1e463951 3092=head3 GvCV() and GvGP() are no longer lvalues
5076a392 3093
1e463951
FC
3094The new GvCV_set() and GvGP_set() macros are now provided to replace
3095assignment to those two macros.
5076a392 3096
1e463951
FC
3097This allows a future commit to eliminate some backref magic between GV
3098and CVs, which will require complete control over assignment to the
3099gp_cv slot.
5076a392 3100
1e463951 3101=head3 CvGV() is no longer an lvalue
5076a392 3102
1e463951
FC
3103Under some circumstances, the C<CvGV()> field of a CV is now
3104reference-counted. To ensure consistent behaviour, direct assignment to
3105it, for example C<CvGV(cv) = gv> is now a compile-time error. A new macro,
3106C<CvGV_set(cv,gv)> has been introduced to perform this operation
3107safely. Note that modification of this field is not part of the public
3108API, regardless of this new macro (and despite its being listed in this section).
5076a392 3109
1e463951 3110=head3 CvSTASH() is no longer an lvalue
5076a392 3111
1e463951
FC
3112The C<CvSTASH()> macro can now only be used as an rvalue. C<CvSTASH_set()>
3113has been added to replace assignment to C<CvSTASH()>. This is to ensure
3114that backreferences are handled properly. These macros are not part of the
3115API.
5076a392 3116
1e463951 3117=head3 Calling conventions for C<newFOROP> and C<newWHILEOP>
5076a392 3118
1e463951
FC
3119The way the parser handles labels has been cleaned up and refactored. As a
3120result, the C<newFOROP()> constructor function no longer takes a parameter
3121stating what label is to go in the state op.
5076a392 3122
1e463951
FC
3123The C<newWHILEOP()> and C<newFOROP()> functions no longer accept a line
3124number as a parameter.
5076a392 3125
1e463951 3126=head3 Flags passed to C<uvuni_to_utf8_flags> and C<utf8n_to_uvuni>
5076a392 3127
1e463951
FC
3128Some of the flags parameters to uvuni_to_utf8_flags() and
3129utf8n_to_uvuni() have changed. This is a result of Perl's now allowing
5076a392
FC
3130internal storage and manipulation of code points that are problematic
3131in some situations. Hence, the default actions for these functions has
3132been complemented to allow these code points. The new flags are
3133documented in L<perlapi>. Code that requires the problematic code
483b16f3 3134points to be rejected needs to change to use the new flags. Some flag
5076a392
FC
3135names are retained for backward source compatibility, though they do
3136nothing, as they are now the default. However the flags
3137C<UNICODE_ALLOW_FDD0>, C<UNICODE_ALLOW_FFFF>, C<UNICODE_ILLEGAL>, and
3138C<UNICODE_IS_ILLEGAL> have been removed, as they stem from a
3139fundamentally broken model of how the Unicode non-character code points
3140should be handled, which is now described in
3141L<perlunicode/Non-character code points>. See also L</Selected Bug Fixes>.
3142
1e463951 3143XXX Which bugs in particular? Selected Bug Fixes is too long for this link
483b16f3
KW
3144to be meaningful right now
3145I don't see the bugs in that section currently -- khw
5076a392 3146
1e463951 3147=head2 Deprecated C APIs
5076a392 3148
1e463951 3149=over
5076a392 3150
1e463951 3151=item C<Perl_ptr_table_clear>
5076a392 3152
1e463951
FC
3153C<Perl_ptr_table_clear> is no longer part of Perl's public API. Calling it
3154now generates a deprecation warning, and it will be removed in a future
3155release.
5076a392 3156
1e463951 3157=item C<sv_compile_2op>
5076a392 3158
1e463951
FC
3159The C<sv_compile_2op()> API function is now deprecated. Searches suggest
3160that nothing on CPAN is using it, so this should have zero impact.
5076a392 3161
1e463951
FC
3162It attempted to provide an API to compile code down to an optree, but failed
3163to bind correctly to lexicals in the enclosing scope. It's not possible to
3164fix this problem within the constraints of its parameters and return value.
5076a392 3165
1e463951 3166=item C<find_rundefsvoffset>
5076a392 3167
1e463951
FC
3168The C<find_rundefsvoffset> function has been deprecated. It appeared that
3169its design was insufficient for reliably getting the lexical C<$_> at
3170run-time.
5076a392 3171
1e463951
FC
3172Use the new C<find_rundefsv> function or the C<UNDERBAR> macro
3173instead. They directly return the right SV representing C<$_>, whether it's
3174lexical or dynamic.
5076a392 3175
1e463951 3176=item C<CALL_FPTR> and C<CPERLscope>
5076a392 3177
1e463951
FC
3178Those are left from an old implementation of C<MULTIPLICITY> using C++ objects,
3179which was removed in Perl 5.8. Nowadays these macros do exactly nothing, so
3180they shouldn't be used anymore.
5076a392 3181
1e463951
FC
3182For compatibility, they are still defined for external C<XS> code. Only
3183extensions defining C<PERL_CORE> must be updated now.
5076a392 3184
1e463951 3185=back
5076a392 3186
1e463951 3187=head2 Other Internal Changes
5076a392 3188
1e463951 3189=head3 Stack unwinding
5076a392 3190
1e463951
FC
3191The protocol for unwinding the C stack at the last stage of a C<die>
3192has changed how it identifies the target stack frame. This now uses
3193a separate variable C<PL_restartjmpenv>, where previously it relied on
3194the C<blk_eval.cur_top_env> pointer in the C<eval> context frame that
3195has nominally just been discarded. This change means that code running
3196during various stages of Perl-level unwinding no longer needs to take
3197care to avoid destroying the ghost frame.
5076a392 3198
1e463951 3199=head3 Scope stack entries
5076a392 3200
1e463951
FC
3201The format of entries on the scope stack has been changed, resulting in a
3202reduction of memory usage of about 10%. In particular, the memory used by
3203the scope stack to record each active lexical variable has been halved.
5076a392 3204
1e463951 3205=head3 Memory allocation for pointer tables
5076a392 3206
1e463951
FC
3207Memory allocation for pointer tables has been changed. Previously
3208C<Perl_ptr_table_store> allocated memory from the same arena system as
3209C<SV> bodies and C<HE>s, with freed memory remaining bound to those arenas
3210until interpreter exit. Now it allocates memory from arenas private to the
3211specific pointer table, and that memory is returned to the system when
3212C<Perl_ptr_table_free> is called. Additionally, allocation and release are
3213both less CPU intensive.
5076a392 3214
1e463951 3215=head3 C<UNDERBAR>
5076a392 3216
1e463951
FC
3217The C<UNDERBAR> macro now calls C<find_rundefsv>. C<dUNDERBAR> is now a
3218noop but should still be used to ensure past and future compatibility.
5076a392 3219
1e463951 3220=head3 String comparison routines renamed
5076a392 3221
1e463951
FC
3222The ibcmp_* functions have been renamed and are now called foldEQ,
3223foldEQ_locale and foldEQ_utf8. The old names are still available as
3224macros.
3225
3226=head3 C<chop> and C<chomp> implementations merged
3227
3228The opcode bodies for C<chop> and C<chomp> and for C<schop> and C<schomp>
3229have been merged. The implementation functions C<Perl_do_chop()> and
3230C<Perl_do_chomp()>, never part of the public API, have been merged and
3231moved to a static function in F<pp.c>. This shrinks the perl binary
3232slightly, and should not affect any code outside the core (unless it is
3233relying on the order of side effects when C<chomp> is passed a I<list> of
3234values).
5076a392
FC
3235
3236=head1 Selected Bug Fixes
3237
e8e35311
FC
3238=head2 I/O
3239
5076a392
FC
3240=over 4
3241
3242=item *
3243
e8e35311 3244Perl no longer produces this warning:
a593b319
FC
3245
3246 $ perl -we 'open my $f, ">", \my $x; binmode $f, "scalar"'
3247 Use of uninitialized value in binmode at -e line 1.
3248
3249=item *
3250
e8e35311
FC
3251Opening a glob reference via C<< open $fh, "E<gt>", \*glob >> will no longer
3252cause the glob to be corrupted when the filehandle is printed to. This would
3253cause perl to crash whenever the glob's contents were accessed
3254[perl #77492].
4ed2cea4
FC
3255
3256=item *
3257
e8e35311
FC
3258PerlIO no longer crashes when called recursively, e.g., from a signal
3259handler. Now it just leaks memory [perl #75556].
4ed2cea4
FC
3260
3261=item *
3262
e8e35311
FC
3263Most I/O functions were not warning for unopened handles unless the
3264'closed' and 'unopened' warnings categories were both enabled. Now only
3265C<use warnings 'unopened'> is necessary to trigger these warnings (as was
438c239f 3266always meant to be the case).
4ed2cea4
FC
3267
3268=item *
3269
438c239f 3270There have been several fixes to PerlIO layers:
e8e35311 3271
438c239f
FC
3272When C<binmode FH, ":crlf"> pushes the C<:crlf> layer on top of the stack,
3273it no longer enables crlf layers lower in the stack, to avoid unexpected
3274results [perl #38456].
4ed2cea4 3275
438c239f
FC
3276Opening a file in C<:raw> mode now does what it advertises to do (first
3277open the file, then binmode it), instead of simply leaving off the top
3278layer [perl #80764].
5076a392 3279
438c239f
FC
3280The three layers C<:pop>, C<:utf8> and C<:bytes> didn't allow stacking when
3281opening a file. For example
e8e35311 3282this:
5076a392 3283
e8e35311 3284 open FH, '>:pop:perlio', 'some.file' or die $!;
5076a392 3285
438c239f
FC
3286Would throw an error: "Invalid argument". This has been fixed in this
3287release [perl #82484].
5076a392 3288
e8e35311
FC
3289=back
3290
3291=head2 Regular Expression Bug Fixes
3292
3293=over
5076a392
FC
3294
3295=item *
3296
e8e35311
FC
3297The regular expression engine no longer loops when matching
3298C<"\N{LATIN SMALL LIGATURE FF}" =~ /f+/i> and similar expressions
cdc10f43 3299[perl #72998] (5.12.1).
5076a392
FC
3300
3301=item *
3302
e8e35311
FC
3303The trie runtime code should no longer allocate massive amounts of memory,
3304fixing #74484.
5076a392
FC
3305
3306=item *
3307
438c239f
FC
3308Syntax errors in C<< (?{...}) >> blocks no longer cause panic messages
3309[perl #2353].
5076a392
FC
3310
3311=item *
3312
438c239f
FC
3313A pattern like C<(?:(o){2})?> no longer causes a "panic" error
3314[perl #39233].
5076a392
FC
3315
3316=item *
3317
438c239f 3318A fatal error in regular expressions containing C<(.*?)> when processing
d430b8e7 3319UTF-8 data has been fixed [perl #75680] (5.12.2).
5076a392
FC
3320
3321=item *
3322
e8e35311 3323An erroneous regular expression engine optimisation that caused regex verbs like
438c239f 3324C<*COMMIT> sometimes to be ignored has been removed.
5076a392
FC
3325
3326=item *
3327
e8e35311
FC
3328The regular expression bracketed character class C<[\8\9]> was effectively the
3329same as C<[89\000]>, incorrectly matching a NULL character. It also gave
3330incorrect warnings that the C<8> and C<9> were ignored. Now C<[\8\9]> is the
3331same as C<[89]> and gives legitimate warnings that C<\8> and C<\9> are
3332unrecognized escape sequences, passed-through.
5076a392
FC
3333
3334=item *
3335
e8e35311
FC
3336A regular expression match in the right-hand side of a global substitution
3337(C<s///g>) that is in the same scope will no longer cause match variables
3338to have the wrong values on subsequent iterations. This can happen when an
3339array or hash subscript is interpolated in the right-hand side, as in
3340C<s|(.)|@a{ print($1), /./ }|g> [perl #19078].
5076a392
FC
3341
3342=item *
3343
438c239f
FC
3344Several cases in which characters in the Latin-1 non-ASCII range (0x80 to
33450xFF) used not to match themselves or used to match both a character class
3346and its complement have been fixed. For instance, U+00E2 could match both
3347C<\w> and C<\W> [perl #78464] [perl #18281] [perl #60156].
5076a392
FC
3348
3349=item *
3350
e8e35311
FC
3351Matching a Unicode character against an alternation containing characters
3352that happened to match continuation bytes in the former's UTF8
3353representation (C<qq{\x{30ab}} =~ /\xab|\xa9/>) would cause erroneous
3354warnings [perl #70998].
5076a392
FC
3355
3356=item *
3357
e8e35311
FC
3358The trie optimisation was not taking empty groups into account, preventing
3359'foo' from matching C</\A(?:(?:)foo|bar|zot)\z/> [perl #78356].
5076a392
FC
3360
3361=item *
3362
e8e35311
FC
3363A pattern containing a C<+> inside a lookahead would sometimes cause an
3364incorrect match failure in a global match (e.g., C</(?=(\S+))/g>)
3365[perl #68564].
5076a392
FC
3366
3367=item *
3368
e8e35311
FC
3369A regular expression optimisation would sometimes cause a match with a
3370C<{n,m}> quantifier to fail when it should match [perl #79152].
5076a392
FC
3371
3372=item *
3373
e8e35311 3374Case insensitive matching in regular expressions compiled under C<use
438c239f
FC
3375locale> now works much more sanely when the pattern or
3376target string is encoded internally in
3377UTF8. Previously, under these conditions the localeness
e8e35311
FC
3378was completely lost. Now, code points above 255 are treated as Unicode,
3379but code points between 0 and 255 are treated using the current locale
438c239f
FC
3380rules, regardless of whether the pattern or the string is encoded in UTF8.
3381The few case-insensitive matches that cross the 255/256 boundary are not
e8e35311
FC
3382allowed. For example, 0xFF does not caselessly match the character at
33830x178, LATIN CAPITAL LETTER Y WITH DIAERESIS, because 0xFF may not be
3384LATIN SMALL LETTER Y in the current locale, and Perl has no way of
3385knowing if that character even exists in the locale, much less what code
3386point it is.
5076a392
FC
3387
3388=item *
3389
e8e35311
FC
3390The C<(?|...)> regular expression construct no longer crashes if the final
3391branch has more sets of capturing parentheses than any other branch. This
3392was fixed in Perl 5.10.1 for the case of a single branch, but that fix did
3393not take multiple branches into account [perl #84746].
5076a392
FC
3394
3395=item *
3396
e8e35311
FC
3397A bug has been fixed in the implementation of C<{...}> quantifiers in
3398regular expressions that prevented the code block in
3399C</((\w+)(?{ print $2 })){2}/> from seeing the C<$2> sometimes
3400[perl #84294].
5076a392 3401
e8e35311 3402=back
5076a392 3403
e8e35311
FC
3404=head2 Syntax/Parsing Bugs
3405
3406=over
5076a392
FC
3407
3408=item *
3409
e8e35311 3410C<when(scalar){...}> no longer crashes, but produces a syntax error
cdc10f43 3411[perl #74114] (5.12.1).
5076a392
FC
3412
3413=item *
3414
e8e35311
FC
3415A label right before a string eval (C<foo: eval $string>) no longer causes
3416the label to be associated also with the first statement inside the eval
3417[perl #74290] (5.12.1).
5076a392
FC
3418
3419=item *
3420
b2c076b5 3421The C<no 5.13.2;> form of C<no> no longer tries to turn on features or
d430b8e7 3422pragmata (i.e., strict) [perl #70075] (5.12.2).
5076a392
FC
3423
3424=item *
3425
b2c076b5
FC
3426C<BEGIN {require 5.12.0}> now behaves as documented, rather than behaving
3427identically to C<use 5.12.0;>. Previously, C<require> in a C<BEGIN> block
3428was erroneously executing the C<use feature ':5.12.0'> and
3429C<use strict;> behaviour, which only C<use> was documented to
3430provide [perl #69050].
5076a392
FC
3431
3432=item *
3433
5076a392
FC
3434A regression introduced in Perl 5.12.0, making
3435C<< my $x = 3; $x = length(undef) >> result in C<$x> set to C<3> has been
d430b8e7 3436fixed. C<$x> will now be C<undef> [perl #85508] (5.12.2).
b2c076b5
FC
3437
3438=item *
3439
3440When strict 'refs' mode is off, C<%{...}> in rvalue context returns
3441C<undef> if its argument is undefined. An optimisation introduced in perl
34425.12.0 to make C<keys %{...}> faster when used as a boolean did not take
3443this into account, causing C<keys %{+undef}> (and C<keys %$foo> when
3444C<$foo> is undefined) to be an error, which it should only be in strict
3445mode [perl #81750].
5076a392
FC
3446
3447=item *
3448
e8e35311 3449Constant-folding used to cause
5076a392 3450
e8e35311 3451 $text =~ ( 1 ? /phoo/ : /bear/)
5076a392 3452
e8e35311
FC
3453to turn into
3454
3455 $text =~ /phoo/
3456
3457at compile time. Now it correctly matches against C<$_> [perl #20444].
5076a392
FC
3458
3459=item *
3460
e8e35311
FC
3461Parsing Perl code (either with string C<eval> or by loading modules) from
3462within a C<UNITCHECK> block no longer causes the interpreter to crash
3463[perl #70614].
5076a392
FC
3464
3465=item *
3466
b2c076b5
FC
3467String evals no longer fail after 2 billion scopes have been
3468compiled [perl #83364].
3469
3470=item *
3471
e8e35311
FC
3472The parser no longer hangs when encountering certain Unicode characters,
3473such as U+387 [perl #74022].
5076a392
FC
3474
3475=item *
3476
b2c076b5
FC
3477Several contexts no longer allow a Unicode character to begin a word
3478that should never begin words, for an example an accent that must follow
3479another character previously could precede all other characters.
5076a392
FC
3480
3481=item *
3482
e8e35311
FC
3483Defining a constant with the same name as one of perl's special blocks
3484(e.g., INIT) stopped working in 5.12.0, but has now been fixed
3485[perl #78634].
5076a392
FC
3486
3487=item *
3488
e8e35311
FC
3489A reference to a literal value used as a hash key (C<$hash{\"foo"}>) used
3490to be stringified, even if the hash was tied [perl #79178].
5076a392
FC
3491
3492=item *
3493
e8e35311
FC
3494A closure containing an C<if> statement followed by a constant or variable
3495is no longer treated as a constant [perl #63540].
5076a392
FC
3496
3497=item *
3498
e8e35311
FC
3499C<state> can now be used with attributes. It used to mean the same thing as
3500C<my> if attributes were present [perl #68658].
5076a392
FC
3501
3502=item *
3503
e8e35311
FC
3504Expressions like C<< @$a > 3 >> no longer cause C<$a> to be mentioned in
3505the "Use of uninitialized value in numeric gt" warning when C<$a> is
3506undefined (since it is not part of the C<E<gt>> expression, but the operand
3507of the C<@>) [perl #72090].
5076a392
FC
3508
3509=item *
3510
e8e35311
FC
3511Accessing an element of a package array with a hard-coded number (as
3512opposed to an arbitrary expression) would crash if the array did not exist.
3513Usually the array would be autovivified during compilation, but typeglob
3514manipulation could remove it, as in these two cases which used to crash:
5076a392 3515
e8e35311
FC
3516 *d = *a; print $d[0];
3517 undef *d; print $d[0];
5076a392 3518
2c389f6c
FC
3519=item *
3520
3521The C<-C> command line option, when used on the shebang line, can now be
3522followed by other options [perl #72434].
3523
3524=item *
3525
3526The C<B> module was returning C<B::OP>s instead of C<B::LOGOP>s for C<entertry> [perl #80622].
3527This was due to a bug in the perl core, not in C<B> itself.
3528
e8e35311 3529=back
5076a392 3530
e262cb24
FC
3531=head2 Stashes, Globs and Method Lookup
3532
3533Perl 5.10.0 introduced a new internal mechanism for caching MROs (method
3534resolution orders, or lists of parent classes; aka "isa" caches) to make
3535method lookup faster (so @ISA arrays would not have to be searched
3536repeatedly). Unfortunately, this brought with it quite a few bugs. Almost
3537all of these have been fixed now, along with a few MRO-related bugs that
3538existed before 5.10.0:
3539
3540=over
3541
3542=item *
3543
3544The following used to have erratic effects on method resolution, because
3545the "isa" caches were not reset or otherwise ended up listing the wrong
3546classes. These have been fixed.
3547
3548=over
3549
3550=item Aliasing packages by assigning to globs [perl #77358]
3551
3552=item Deleting packages by deleting their containing stash elements
3553
3554=item Undefining the glob containing a package (C<undef *Foo::>)
3555
3556=item Undefining an ISA glob (C<undef *Foo::ISA>)
3557
3558=item Deleting an ISA stash element (C<delete $Foo::{ISA}>)
3559
3560=item Sharing @ISA arrays between classes (via C<*Foo::ISA = \@Bar::ISA> or
3561C<*Foo::ISA = *Bar::ISA>) [perl #77238]
3562
3563=back
3564