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Correct the File::stat version in perldelta
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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
5076a392
FC
1186C<Archive::Extract> has been upgraded from version 0.38 to 0.48.
1187
1188Updates since 0.38 include: a safe print method that guards
1189Archive::Extract from changes to $\; a fix to the tests when run in core
1984204c
FC
1190perl; support for TZ files; a modification for the lzma
1191logic to favour IO::Uncompress::Unlzma; and a fix
1192for an issue with NetBSD-current and its new unzip
5076a392
FC
1193executable.
1194
1195=item *
1196
1197C<Archive::Tar> has been upgraded from version 1.54 to 1.76.
1198
1984204c
FC
1199Important changes since 1.54 include the following:
1200
1201=over
1202
1203=item *
1204
1205Compatibility with busybox implementations of tar
1206
1207=item *
1208
1209A fix so that C<write()> and C<create_archive()>
1210close only handles they opened
1211
1212=item *
1213
1214A bug was fixed regarding the exit code of extract_archive.
5076a392 1215
1984204c
FC
1216=item *
1217
4f978a3b 1218The C<ptar> utility has a new option to allow safe
5076a392
FC
1219creation of tarballs without world-writable files on Windows, allowing those
1220archives to be uploaded to CPAN.
1221
1984204c
FC
1222=item *
1223
1224A new ptargrep utility for using regular expressions against
5076a392
FC
1225the contents of files in a tar archive.
1226
1984204c
FC
1227=item *
1228
1229Pax extended headers are now skipped.
1230
1231=back
5076a392
FC
1232
1233=item *
1234
5076a392
FC
1235C<B> has been upgraded from version 1.23 to 1.27.
1236
1237It no longer crashes when taking apart a C<y///> containing characters
1238outside the octet range or compiled in a C<use utf8> scope.
1239
1240The size of the shared object has been reduced by about 40%, with no
1241reduction in functionality.
1242
1243=item *
1244
1245C<B::Concise> has been upgraded from version 0.78 to 0.82.
1246
1247B::Concise marks rv2sv, rv2av and rv2hv ops with the new OPpDEREF flag
1248as "DREFed".
1249
1250It no longer produces mangled output with the C<-tree> option
1251[perl #80632].
1252
1253=item *
1254
5076a392
FC
1255C<B::Deparse> has been upgraded from version 0.96 to 1.02.
1256
1984204c 1257The deparsing of a nextstate op has changed when it has both a
5076a392
FC
1258change of package (relative to the previous nextstate), or a change of
1259C<%^H> or other state, and a label. Previously the label was emitted
cdc10f43 1260first, but now the label is emitted last (5.12.1).
5076a392 1261
5a553547
FC
1262The C<no 5.13.2> or similar form is now correctly handled by B::Deparse
1263(5.12.3).
5076a392
FC
1264
1265B::Deparse now properly handles the code that applies a conditional
1266pattern match against implicit C<$_> as it was fixed in [perl #20444].
1267
1984204c
FC
1268Deparsing of C<our> followed by a variable with funny characters
1269(as permitted under the C<utf8> pragma) has also been fixed [perl #33752].
5076a392
FC
1270
1271=item *
1272
d430b8e7 1273C<Carp> has been upgraded from version 1.15 to 1.19.
5076a392
FC
1274
1275L<Carp> now detects incomplete L<caller()|perlfunc/"caller EXPR"> overrides and
d430b8e7
FC
1276avoids using bogus C<@DB::args>. To provide backtraces,
1277Carp relies on particular behaviour of the C<caller>
1278built-in. Carp now detects if other code has
5076a392 1279overridden this with an incomplete implementation, and modifies its backtrace
d430b8e7
FC
1280accordingly. Previously incomplete overrides would cause incorrect values
1281in backtraces (best case), or obscure fatal errors (worst case).
5076a392
FC
1282
1283This fixes certain cases of C<Bizarre copy of ARRAY> caused by modules
d430b8e7 1284overriding C<caller()> incorrectly (5.12.2).
5076a392 1285
1984204c 1286It now also avoids using regular expressions that cause perl to
5076a392
FC
1287load its Unicode tables, in order to avoid the 'BEGIN not safe after
1288errors' error that will ensue if there has been a syntax error
1289[perl #82854].
1290
1291=item *
1292
1293C<CGI> has been upgraded from version 3.48 to 3.51.
1294
1295This provides the following security fixes: the MIME boundary in
1984204c
FC
1296multipart_init is now random and the handling of
1297newlines embedded in header values has been improved.
5076a392
FC
1298
1299=item *
1300
5076a392
FC
1301C<Compress::Raw::Bzip2> has been upgraded from version 2.024 to 2.033.
1302
1984204c 1303It has been updated to use bzip2 1.0.6.
5076a392
FC
1304
1305=item *
1306
f75b7efc 1307C<CPAN> has been upgraded from version 1.94_56 to 1.9600.
1984204c
FC
1308
1309Major highlights:
5076a392
FC
1310
1311=over 4
1312
1984204c 1313=item * much less configuration dialog hassle
5076a392 1314
1984204c 1315=item * support for META/MYMETA.json
5076a392 1316
1984204c 1317=item * support for local::lib
5076a392 1318
1984204c 1319=item * support for HTTP::Tiny to reduce the dependency on ftp sites
5076a392 1320
1984204c 1321=item * automatic mirror selection
5076a392 1322
1984204c 1323=item * iron out all known bugs in configure_requires
5076a392 1324
1984204c
FC
1325=item * support for distributions compressed with bzip2
1326
1327=item * allow Foo/Bar.pm on the commandline to mean Foo::Bar
1328
1329=back
5076a392
FC
1330
1331=item *
1332
d430b8e7
FC
1333C<CPANPLUS> has been upgraded from version 0.90 to 0.9103.
1334
1335A change to F<cpanp-run-perl>
1336resolves L<RT #55964|http://rt.cpan.org/Public/Bug/Display.html?id=55964>
1337and L<RT #57106|http://rt.cpan.org/Public/Bug/Display.html?id=57106>, both
1338of which related to failures to install distributions that use
1339C<Module::Install::DSL> (5.12.2).
5076a392 1340
1984204c
FC
1341A dependency on Config was not recognised as a
1342core module dependency. This has been fixed.
5076a392 1343
1984204c 1344CPANPLUS now includes support for META.json and MYMETA.json.
5076a392
FC
1345
1346=item *
1347
5076a392
FC
1348C<Data::Dumper> has been upgraded from version 2.125 to 2.130_02.
1349
4ed2cea4
FC
1350The indentation used to be off when C<$Data::Dumper::Terse> was set. This
1351has been fixed [perl #73604].
1352
1984204c
FC
1353This upgrade also fixes a crash when using custom sort functions that might
1354cause the stack to change [perl #74170].
5076a392
FC
1355
1356C<Dumpxs> no longer crashes with globs returned by C<*$io_ref>
1357[perl #72332].
1358
1359=item *
1360
5076a392
FC
1361C<Devel::DProf> has been upgraded from version 20080331.00 to 20110228.00.
1362
1363Merely loading C<Devel::DProf> now no longer triggers profiling to start.
1364C<use Devel::DProf> and C<perl -d:DProf ...> still behave as before and start
1365the profiler.
1366
1367NOTE: C<Devel::DProf> is deprecated and will be removed from a future
1984204c 1368version of Perl. We strongly recommend that you install and use
5076a392
FC
1369L<Devel::NYTProf> instead, as it offers significantly improved
1370profiling and reporting.
1371
1372=item *
1373
5076a392
FC
1374C<diagnostics> has been upgraded from version 1.19 to 1.22.
1375
1376It now renders pod links slightly better, and has been taught to find
1377descriptions for messages that share their descriptions with other
1378messages.
1379
1380=item *
1381
1382C<Digest::MD5> has been upgraded from version 2.39 to 2.51.
1383
1384It is now safe to use this module in combination with threads.
1385
1386=item *
1387
1388C<Digest::SHA> has been upgraded from version 5.47 to 5.61.
1389
1390C<shasum> now more closely mimics C<sha1sum>/C<md5sum>.
1391
1392C<Addfile> accepts all POSIX filenames.
1393
1984204c
FC
1394New SHA-512/224 and SHA-512/256 transforms (ref. NIST Draft FIPS 180-4
1395[February 2011])
5076a392
FC
1396
1397=item *
1398
5076a392
FC
1399C<DynaLoader> has been upgraded from version 1.10 to 1.12.
1400
1401It fixes a buffer overflow when passed a very long file name.
1402
1403It no longer inherits from AutoLoader; hence it no longer
1404produces weird error messages for unsuccessful method calls on classes that
1405inherit from DynaLoader [perl #84358].
1406
1407=item *
1408
1409C<Encode> has been upgraded from version 2.39 to 2.42.
1410
1411Now, all 66 Unicode non-characters are treated the same way U+FFFF has
1984204c
FC
1412always been treated; in cases when it was disallowed, all 66 are
1413disallowed; in those cases where it warned, all 66 warn.
5076a392
FC
1414
1415=item *
1416
5076a392
FC
1417C<Errno> has been upgraded from version 1.11 to 1.13.
1418
1419The implementation of C<Errno> has been refactored to use about 55% less memory.
5076a392
FC
1420
1421On some platforms with unusual header files, like Win32/gcc using mingw64
1422headers, some constants which weren't actually error numbers have been exposed
1423by C<Errno>. This has been fixed [perl #77416].
1424
1425=item *
1426
1427C<Exporter> has been upgraded from version 5.64_01 to 5.64_03.
1428
1429Exporter no longer overrides C<$SIG{__WARN__}> [perl #74472]
1430
1431=item *
1432
5076a392
FC
1433C<ExtUtils::Constant> has been upgraded from 0.22 to 0.23.
1434
1435The C<AUTOLOAD> helper code generated by C<ExtUtils::Constant::ProxySubs>
1436can now C<croak> for missing constants, or generate a complete C<AUTOLOAD>
1984204c
FC
1437subroutine in XS, allowing simplification of many modules that use it
1438(C<Fcntl>, C<File::Glob>, C<GDBM_File>, C<I18N::Langinfo>, C<POSIX>,
1439C<Socket>).
5076a392
FC
1440
1441C<ExtUtils::Constant::ProxySubs> can now optionally push the names of all
1984204c 1442constants onto the package's C<@EXPORT_OK>.
5076a392
FC
1443
1444=item *
1445
5076a392
FC
1446C<File::DosGlob> has been upgraded from version 1.01 to 1.03.
1447
1448It allows patterns containing literal parentheses (they no longer need to
1984204c
FC
1449be escaped). On Windows, it no longer
1450adds an extra F<./> to the file names
5076a392
FC
1451returned when the pattern is a relative glob with a drive specification,
1452like F<c:*.pl> [perl #71712].
1453
1454=item *
1455
1456C<File::Fetch> has been upgraded from version 0.24 to 0.32.
1457
1458C<HTTP::Lite> is now supported for 'http' scheme.
1459
1460The C<fetch> utility is supported on FreeBSD, NetBSD and
1461Dragonfly BSD for the C<http> and C<ftp> schemes.
1462
1463=item *
1464
1465C<File::Find> has been upgraded from version 1.15 to 1.18.
1466
1984204c 1467It improves handling of backslashes on Windows, so that paths like
5076a392
FC
1468F<c:\dir\/file> are no longer generated [perl #71710].
1469
1470=item *
1471
d430b8e7
FC
1472C<File::Spec> has been upgraded from version 3.31 to 3.33.
1473
1474Several portability fixes were made in C<File::Spec::VMS>: a colon is now
1475recognized as a delimiter in native filespecs; caret-escaped delimiters are
1476recognized for better handling of extended filespecs; C<catpath()> returns
1477an empty directory rather than the current directory if the input directory
1478name is empty; C<abs2rel()> properly handles Unix-style input (5.12.2).
1479
1480=item *
1481
46ba0657 1482C<File::stat> has been upgraded from 1.02 to 1.05.
5076a392
FC
1483
1484The C<-x> and C<-X> file test operators now work correctly under the root
1485user.
1486
1487=item *
1488
dc6857fd 1489C<GDBM_File> has been upgraded from 1.10 to 1.14.
5076a392
FC
1490
1491This fixes a memory leak when DBM filters are used.
1492
1493=item *
1494
6e107b45 1495C<Hash::Util> has been upgraded from 0.07 to 0.11.
5076a392 1496
1984204c
FC
1497Hash::Util no longer emits spurious "uninitialized" warnings when
1498recursively locking hashes that have undefined values [perl #74280].
5076a392
FC
1499
1500=item *
1501
eec33fe6
FR
1502C<I18N::Collate> has been upgraded from version 1.01 to 1.02.
1503
1504=item *
1505
ad5f8f47 1506C<I18N::Langinfo> has been upgraded from version 0.03 to 0.08.
5076a392
FC
1507
1508C<langinfo()> now defaults to using C<$_> if there is no argument given, just
5334145a 1509as the documentation has always claimed.
5076a392
FC
1510
1511=item *
1512
c41635f7
FR
1513C<I18N::LangTags> has been upgraded from version 0.35 to 0.35_01.
1514
1515=item *
1516
98a6a4ff
FR
1517C<if> has been upgraded from version 0.05 to 0.0601.
1518
1519=item *
1520
f6ff7fb6
FR
1521C<IO> has been upgraded from version 1.25_02 to 1.25_04.
1522
1523=item *
1524
d13528c5 1525C<IO::Select> has been upgraded from version 1.17 to 1.20.
5076a392
FC
1526
1527It now allows IO::Handle objects (and objects in derived classes) to be
1528removed from an IO::Select set even if the underlying file descriptor is
1529closed or invalid.
1530
1531=item *
1532
d07561d3 1533C<IPC::Cmd> has been upgraded from version 0.54 to 0.70.
5076a392 1534
1984204c
FC
1535Resolves an issue with splitting Win32 command lines. An argument
1536consisting of the single character "0" used to be omitted (CPAN RT #62961).
5076a392
FC
1537
1538=item *
1539
3f16e4eb 1540C<IPC::Open3> has been upgraded from 1.05 to 1.09.
5076a392 1541
4ed2cea4
FC
1542C<open3> now produces an error if the C<exec> call fails, allowing this
1543condition to be distinguished from a child process that exited with a
1544non-zero status [perl #72016].
1545
5076a392
FC
1546The internal C<xclose> routine now knows how to handle file descriptors, as
1547documented, so duplicating STDIN in a child process using its file
1548descriptor now works [perl #76474].
1549
1550=item *
1551
c8b41807
FR
1552C<IPC::SysV> has been upgraded from version 2.01 to 2.03.
1553
1554=item *
1555
ef79f038
FR
1556C<lib> has been upgraded from version 0.62 to 0.63.
1557
1558=item *
1559
5b1884f4 1560C<Locale::Maketext> has been upgraded from version 1.14 to 1.19.
5076a392 1561
1984204c 1562Locale::Maketext now supports external caches.
5076a392 1563
1984204c
FC
1564This upgrade also fixes an infinite loop in
1565C<Locale::Maketext::Guts::_compile()> when
5076a392
FC
1566working with tainted values (CPAN RT #40727).
1567
1984204c 1568C<< ->maketext >> calls will now back up and restore C<$@> so that error
5076a392
FC
1569messages are not suppressed (CPAN RT #34182).
1570
1571=item *
1572
3811bd2b
FR
1573C<Log::Message> has been upgraded from version 0.02 to 0.04.
1574
1575=item *
1576
8eb65377
FR
1577C<Log::Message::Simple> has been upgraded from version 0.06 to 0.08.
1578
1579=item *
1580
5076a392
FC
1581C<Math::BigInt> has been upgraded from version 1.89_01 to 1.994.
1582
1583This fixes, among other things, incorrect results when computing binomial
1584coefficients [perl #77640].
1585
1984204c 1586It also prevents C<sqrt($int)> from crashing under C<use bigrat;>
5076a392
FC
1587[perl #73534].
1588
1589=item *
1590
846c1cec
FR
1591C<Math::BigInt::FastCalc> has been upgraded from version 0.19 to 0.28.
1592
1593=item *
1594
fce4aef3
FR
1595C<Math::BigRat> has been upgraded from version 0.24 to 0.26_02.
1596
1597=item *
1598
12e26027
FR
1599C<Memoize> has been upgraded from version 1.01_03 to 1.02.
1600
1601=item *
1602
5076a392
FC
1603C<MIME::Base64> has been upgraded from 3.08 to 3.13.
1604
1605Includes new functions to calculate the length of encoded and decoded
1606base64 strings.
1607
1608Now provides C<encode_base64url> and C<decode_base64url> functions to process
1609the base64 scheme for "URL applications".
1610
1611=item *
1612
1613C<Module::Build> has been upgraded from version 0.3603 to 0.3800.
1614
1615A notable change is the deprecation of several modules.
1616Module::Build::Version has been deprecated and Module::Build now relies
1617directly upon L<version>. Module::Build::ModuleInfo has been deprecated in
1618favor of a standalone copy of it called L<Module::Metadata>.
1619Module::Build::YAML has been deprecated in favor of L<CPAN::Meta::YAML>.
1620
1621Module::Build now also generates META.json and MYMETA.json files
1622in accordance with version 2 of the CPAN distribution metadata specification,
1623L<CPAN::Meta::Spec>. The older format META.yml and MYMETA.yml files are
1624still generated, as well.
1625
1626=item *
1627
7259fe26 1628C<Module::CoreList> has been upgraded from version 2.29 to 2.47.
5076a392
FC
1629
1630Besides listing the updated core modules of this release, it also stops listing
1984204c 1631the C<Filespec> module. That module never existed in core. The scripts
5076a392 1632generating C<Module::CoreList> confused it with C<VMS::Filespec>, which actually
1984204c 1633is a core module as of perl 5.8.7.
5076a392
FC
1634
1635=item *
1636
193af05b
FR
1637C<Module::Load> has been upgraded from version 0.16 to 0.18.
1638
1639=item *
1640
5b3a054f
FR
1641C<Module::Load::Conditional> has been upgraded from version 0.34 to 0.44.
1642
1643=item *
1644
4f978a3b
FR
1645C<NDBM_File> has been upgraded from version 1.08 to 1.11.
1646
1647This fixes a memory leak when DBM filters are used.
1648
1649=item *
1650
d0aa5c91
FR
1651C<Net::Ping> has been upgraded from version 2.36 to 2.38.
1652
1653=item *
1654
d44b8a8c
FR
1655C<NEXT> has been upgraded from version 0.64 to 0.65.
1656
1657=item *
1658
678d4fd4
FR
1659C<Object::Accessor> has been upgraded from version 0.36 to 0.38.
1660
1661=item *
1662
34188656 1663C<ODBM_File> have been upgraded from version 1.07 to 1.10.
5076a392
FC
1664
1665This fixes a memory leak when DBM filters are used.
1666
1667=item *
1668
77be713d 1669C<overload> has been upgraded from 1.10 to 1.12.
5076a392
FC
1670
1671C<overload::Method> can now handle subroutines that are themselves blessed
1672into overloaded classes [perl #71998].
1673
5076a392
FC
1674The documentation has greatly improved. See L</Documentation> below.
1675
1676=item *
1677
f84c796e
FR
1678C<Params::Check> has been upgraded from version 0.26 to 0.28.
1679
1680=item *
1681
550ee92b
FR
1682C<parent> has been upgraded from version 0.223 to 0.225.
1683
1684=item *
1685
5076a392
FC
1686C<Parse::CPAN::Meta> has been upgraded from version 1.40 to 1.4401.
1687
1984204c 1688The latest Parse::CPAN::Meta can now read YAML and JSON files using
5076a392
FC
1689L<CPAN::Meta::YAML> and L<JSON::PP>, which are now part of the Perl core.
1690
1691=item *
1692
5076a392
FC
1693C<PerlIO::scalar> has been upgraded from 0.07 to 0.11.
1694
1695A C<read> after a C<seek> beyond the end of the string no longer thinks it
1696has data to read [perl #78716].
1697
1698=item *
1699
be3c8498
FR
1700C<Pod::LaTeX> has been upgraded from version 0.58 to 0.59.
1701
1702=item *
1703
fd8a2e89
FR
1704C<Pod::Perldoc> has been upgraded from version 3.15_02 to 3.15_03.
1705
1706=item *
1707
5bcb6583
FR
1708C<Pod::Simple> has been upgraded from version 3.13 to 3.16.
1709
1710=item *
1711
abb8c779 1712C<POSIX> has been upgraded from 1.19 to 1.24.
5076a392
FC
1713
1714It now includes constants for POSIX signal constants.
1715
1716=item *
1717
1984204c 1718C<re> has been upgraded from version 0.11 to 0.17.
5076a392
FC
1719
1720New C<use re "/flags"> pragma
1721
5076a392 1722The C<regmust> function used to crash when called on a regular expression
1984204c 1723belonging to a pluggable engine. Now it croaks instead.
5076a392
FC
1724
1725C<regmust> no longer leaks memory.
1726
1727=item *
1728
1729C<Safe> has been upgraded from version 2.25 to 2.29.
1730
cdc10f43
FC
1731Coderefs returned by C<reval()> and C<rdo()> are now wrapped via
1732C<wrap_code_refs> (5.12.1).
1733
5076a392
FC
1734This fixes a possible infinite loop when looking for coderefs.
1735
cdc10f43 1736It adds several version::vxs::* routines to the default share.
5076a392
FC
1737
1738=item *
1739
5076a392
FC
1740C<SelfLoader> has been upgraded from 1.17 to 1.18.
1741
1742It now works in taint mode [perl #72062].
1743
1744=item *
1745
1746C<sigtrap> has been upgraded from version 1.04 to 1.05.
1747
1748It no longer tries to modify read-only arguments when generating a
1749backtrace [perl #72340].
1750
1751=item *
1752
1984204c 1753C<Socket> has been upgraded from version 1.87 to 1.94.
5076a392 1754
1984204c 1755See L</IPv6 support>, above.
5076a392
FC
1756
1757=item *
1758
1759C<Storable> has been upgraded from version 2.22 to 2.27.
1760
1761Includes performance improvement for overloaded classes.
1762
5076a392 1763This adds support for serialising code references that contain UTF-8 strings
1984204c
FC
1764correctly. The Storable minor version
1765number changed as a result, meaning that
5076a392
FC
1766Storable users who set C<$Storable::accept_future_minor> to a C<FALSE> value
1767will see errors (see L<Storable/FORWARD COMPATIBILITY> for more details).
1768
1769Freezing no longer gets confused if the Perl stack gets reallocated
1770during freezing [perl #80074].
1771
1772=item *
1773
90c6e78f
FR
1774C<Term::ANSIColor> has been upgraded from version 2.02 to 3.00.
1775
1776=item *
1777
d9f2f059
FR
1778C<Term::UI> has been upgraded from version 0.20 to 0.26.
1779
1780=item *
1781
80ebb519
FR
1782C<Test::Harness> has been upgraded from version 3.17 to 3.23.
1783
1784=item *
1785
5076a392
FC
1786C<Test::Simple> has been upgraded from version 0.94 to 0.98.
1787
1788Among many other things, subtests without a C<plan> or C<no_plan> now have an
1789implicit C<done_testing()> added to them.
1790
1791=item *
1792
5076a392
FC
1793C<Thread::Semaphore> has been upgraded from version 2.09 to 2.12.
1794
1984204c
FC
1795It provides two new methods that give more control over the decrementing of
1796semaphores: C<down_nb> and C<down_force>.
5076a392
FC
1797
1798=item *
1799
f0d895e1
FR
1800C<Thread::Queue> has been upgraded from version 2.11 to 2.12.
1801
1802=item *
1803
1a6b954e
FR
1804C<threads> has been upgraded from version 1.75 to 1.83.
1805
1806=item *
1807
55816daa
FR
1808C<threads::shared> has been upgraded from version 1.32 to 1.36.
1809
1810=item *
1811
5076a392
FC
1812C<Tie::Hash> has been upgraded from version 1.03 to 1.04.
1813
1814Calling C<< Tie::Hash-E<gt>TIEHASH() >> used to loop forever. Now it C<croak>s.
1815
1816=item *
1817
ed68b07e
FR
1818C<Tie::RefHash> has been upgraded from version 1.38 to 1.39.
1819
1820=item *
1821
bb3c221a
FR
1822C<Time::HiRes> has been upgraded from version 1.9719 to 1.9721_01.
1823
1824=item *
1825
97fa568b
FR
1826C<Time::Local> has been upgraded from version 1.1901_01 to 1.2000.
1827
1828=item *
1829
a83cb732
FR
1830C<Time::Piece> has been upgraded from version 1.15_01 to 1.20_01.
1831
1832=item *
1833
5076a392
FC
1834C<Unicode::Collate> has been upgraded from version 0.52_01 to 0.73.
1835
1984204c 1836Unicode::Collate has been updated to use Unicode 6.0.0.
5076a392 1837
1984204c
FC
1838Unicode::Collate::Locale now supports a plethora of new locales: ar, be,
1839bg, de__phonebook, hu, hy, kk, mk, nso, om, tn, vi, hr, ig, ja, ko, ru, sq,
1840se, sr, to, uk, zh, zh__big5han, zh__gb2312han, zh__pinyin and zh__stroke.
5076a392
FC
1841
1842The following modules have been added:
1843
1844C<Unicode::Collate::CJK::Big5> for C<zh__big5han> which makes
1845tailoring of CJK Unified Ideographs in the order of CLDR's big5han ordering.
1846
1847C<Unicode::Collate::CJK::GB2312> for C<zh__gb2312han> which makes
1848tailoring of CJK Unified Ideographs in the order of CLDR's gb2312han ordering.
1849
1850C<Unicode::Collate::CJK::JISX0208> which makes tailoring of 6355 kanji
1851(CJK Unified Ideographs) in the JIS X 0208 order.
1852
1853C<Unicode::Collate::CJK::Korean> which makes tailoring of CJK Unified Ideographs
1854in the order of CLDR's Korean ordering.
1855
1856C<Unicode::Collate::CJK::Pinyin> for C<zh__pinyin> which makes
1857tailoring of CJK Unified Ideographs in the order of CLDR's pinyin ordering.
1858
1859C<Unicode::Collate::CJK::Stroke> for C<zh__stroke> which makes
1860tailoring of CJK Unified Ideographs in the order of CLDR's stroke ordering.
1861
5076a392
FC
1862This also sees the switch from using the pure-perl version of this
1863module to the XS version.
1864
1865=item *
1866
ec52b54b
FR
1867C<Unicode::Normalize> has been upgraded from version 1.03 to 1.10.
1868
1869=item *
1870
5076a392
FC
1871C<Unicode::UCD> has been upgraded from version 0.27 to 0.32.
1872
1984204c
FC
1873A new function, C<Unicode::UCD::num()>, has been added. This function
1874returns the numeric value of the string passed it or C<undef> if the string
1875in its entirety has no "safe" numeric value. (For more detail, and for the
1876definition of "safe", see L<Unicode::UCD/num>.)
5076a392 1877
1984204c 1878This upgrade also includes a number of bug fixes:
5076a392
FC
1879
1880=over 4
1881
1882=item charinfo()
1883
1884=over 4
1885
1886=item *
1887
1888It is now updated to Unicode Version 6 with Corrigendum #8, except,
1889as with Perl 5.14, the code point at U+1F514 has no name.
1890
1891=item *
1892
1893The Hangul syllable code points have the correct names, and their
1894decompositions are always output without requiring L<Lingua::KO::Hangul::Util>
1895to be installed.
1896
1897=item *
1898
54c7bb16
FC
1899The CJK (Chinese-Japanese-Korean) code points U+2A700 to U+2B734
1900and U+2B740 to U+2B81D are now properly handled.
5076a392
FC
1901
1902=item *
1903
1904The numeric values are now output for those CJK code points that have them.
1905
1906=item *
1907
1908The names that are output for code points with multiple aliases are now the
1909corrected ones.
1910
1911=back
1912
1913=item charscript()
1914
1915This now correctly returns "Unknown" instead of C<undef> for the script
1916of a code point that hasn't been assigned another one.
1917
1918=item charblock()
1919
1920This now correctly returns "No_Block" instead of C<undef> for the block
1921of a code point that hasn't been assigned to another one.
1922
1923=back
1924
5076a392
FC
1925=item *
1926
1927C<version> has been upgraded from 0.82 to 0.88.
1928
1984204c 1929Due to a bug, now fixed, the C<is_strict> and C<is_lax> functions did not
cdc10f43 1930work when exported (5.12.1).
5076a392
FC
1931
1932=item *
1933
3e625598 1934C<warnings> has been upgraded from version 1.09 to 1.12.
5076a392
FC
1935
1936Calling C<use warnings> without arguments is now significantly more efficient.
1937
4f978a3b
FR
1938=item *
1939
1940C<warnings::register> have been upgraded from version 1.01 to 1.02.
1941
5076a392
FC
1942It is now possible to register warning categories other than the names of
1943packages using C<warnings::register>. See L<perllexwarn> for more information.
1944
1945=item *
1946
62e270c2
FR
1947C<XSLoader> has been upgraded from version 0.10 to 0.13.
1948
1949=item *
1950
5076a392
FC
1951C<VMS::DCLsym> has been upgraded from version 1.03 to 1.05.
1952
1953Two bugs have been fixed [perl #84086]:
1954
1955The symbol table name was lost when tying a hash, due to a thinko in
1956C<TIEHASH>. The result was that all tied hashes interacted with the
1957local symbol table.
1958
1959Unless a symbol table name had been explicitly specified in the call
1960to the constructor, querying the special key ':LOCAL' failed to
1961identify objects connected to the local symbol table.
1962
1963=item *
1964
1965C<Win32> has been upgraded from version 0.39 to 0.44.
1966
1984204c
FC
1967This release has several new functions: C<Win32::GetSystemMetrics>,
1968C<Win32::GetProductInfo>, C<Win32::GetOSDisplayName>.
5076a392 1969
1984204c
FC
1970The names returned by C<Win32::GetOSName> and C<Win32::GetOSDisplayName>
1971have been corrected.
5076a392 1972
5076a392
FC
1973=back
1974
5076a392
FC
1975=head2 Removed Modules and Pragmata
1976
1977The following modules have been removed from the core distribution, and if
1978needed should be installed from CPAN instead.
1979
1980=over
1981
4f978a3b
FR
1982=item *
1983
1984C<Class::ISA> has been removed from the Perl core. Prior version was 0.36.
5076a392 1985
4f978a3b
FR
1986=item *
1987
1988C<Pod::Plainer> has been removed from the Perl core. Prior version was 1.02.
1989
1990=item *
5076a392 1991
4f978a3b 1992C<Switch> has been removed from the Perl core. Prior version was 2.16.
5076a392
FC
1993
1994=back
1995
1996The removal of C<Shell> has been deferred until after 5.14, as the
1997implementation of C<Shell> shipped with 5.12.0 did not correctly issue the
1998warning that it was to be removed from core.
1999
2000=head1 Documentation
2001
5076a392
FC
2002=head2 New Documentation
2003
41e29def 2004=head3 L<perlgpl>
5076a392
FC
2005
2006L<perlgpl> has been updated to contain GPL version 1, as is included in the
cdc10f43 2007F<README> distributed with perl (5.12.1).
5076a392 2008
41e29def 2009=head3 Perl 5.12.x delta files
5076a392 2010
41e29def
FC
2011The perldelta files for Perl 5.12.1 to 5.12.3 have been added from the
2012maintenance branch: L<perl5121delta>, L<perl5122delta>, L<perl5123delta>.
5076a392
FC
2013
2014=head3 L<perlpodstyle>
2015
2016New style guide for POD documentation,
2017split mostly from the NOTES section of the pod2man man page.
2018
41e29def
FC
2019=head3 L<perlsource>, L<perlinterp>, L<perlhacktut>, and L<perlhacktips>
2020
2021See L</L<perlhack> and perlrepository revamp>, below.
5076a392
FC
2022
2023=head2 Changes to Existing Documentation
2024
41e29def 2025=head3 L<perlmodlib> is now complete
4ed2cea4
FC
2026
2027The perlmodlib page that came with Perl 5.12.0 was missing a lot of
2028modules, due to a bug in the script that generates the list. This has been
cdc10f43 2029fixed [perl #74332] (5.12.1).
4ed2cea4 2030
41e29def 2031=head3 Replace wrong tr/// table in L<perlebcdic>
5076a392 2032
41e29def 2033L<perlebcdic> contains a helpful table to use in tr/// to convert
5076a392
FC
2034between EBCDIC and Latin1/ASCII. Unfortunately, the table was the
2035inverse of the one it describes, though the code that used the table
2036worked correctly for the specific example given.
2037
2038The table has been changed to its inverse, and the sample code changed
2039to correspond, as this is easier for the person trying to follow the
2040instructions since deriving the old table is somewhat more complicated.
2041
2042The table has also been changed to hex from octal, as that is more the norm
2043these days, and the recipes in the pod altered to print out leading
41e29def 2044zeros to make all the values the same length.
5076a392 2045
41e29def 2046=head3 Tricks for user-defined casing
5076a392 2047
41e29def
FC
2048L<perlunicode> now contains an explanation of how to override, mangle
2049and otherwise tweak the way perl handles upper-, lower- and other-case
2050conversions on Unicode data, and how to provide scoped changes to alter
2051one's own code's behaviour without stomping on anybody else.
5076a392
FC
2052
2053=head3 INSTALL explicitly states the requirement for C89
2054
d430b8e7
FC
2055This was already true but it's now Officially Stated For The Record
2056(5.12.2).
5076a392 2057
41e29def 2058=head3 Explanation of C<\xI<HH>> and C<\oI<OOO>> escapes
5076a392 2059
41e29def
FC
2060L<perlop> has been updated with more detailed explanation of these two
2061character escapes.
5076a392 2062
41e29def 2063=head3 C<-0I<NNN>> switch
5076a392 2064
41e29def 2065In L<perlrun>, the behavior of the C<-0NNN> switch for C<-0400> or higher
d430b8e7 2066has been clarified (5.12.2).
5076a392 2067
cdc10f43
FC
2068=head3 Maintenance policy
2069
2070L<perlpolicy> now contains the policy on what patches are acceptable for
2071maintenance branches (5.12.1).
2072
41e29def 2073=head3 Deprecation policy
5076a392 2074
41e29def 2075L<perlpolicy> now contains the policy on compatibility and deprecation
d430b8e7 2076along with definitions of terms like "deprecation" (5.12.2).
5076a392 2077
41e29def 2078=head3 New descriptions in L<perldiag>
5076a392
FC
2079
2080The following existing diagnostics are now documented:
2081
2082=over 4
2083
2084=item *
2085
2086L<Ambiguous use of %c resolved as operator %c|perldiag/"Ambiguous use of %c resolved as operator %c">
2087
2088=item *
2089
2090L<Ambiguous use of %c{%s} resolved to %c%s|perldiag/"Ambiguous use of %c{%s} resolved to %c%s">
2091
2092=item *
2093
2094L<Ambiguous use of %c{%s%s} resolved to %c%s%s|perldiag/"Ambiguous use of %c{%s%s} resolved to %c%s%s">
2095
2096=item *
2097
2098L<Ambiguous use of -%s resolved as -&%s()|perldiag/"Ambiguous use of -%s resolved as -&%s()">
2099
2100=item *
2101
2102L<Invalid strict version format (%s)|perldiag/"Invalid strict version format (%s)">
2103
2104=item *
2105
2106L<Invalid version format (%s)|perldiag/"Invalid version format (%s)">
2107
2108=item *
2109
2110L<Invalid version object|perldiag/"Invalid version object">
2111
2112=back
2113
5076a392
FC
2114=head3 L<perlbook>
2115
41e29def 2116L<perlbook> has been expanded to cover many more popular books.
5076a392 2117
41e29def 2118=head3 C<SvTRUE> macro
5076a392 2119
41e29def
FC
2120The documentation for the C<SvTRUE> macro in
2121L<perlapi> was simply wrong in stating that
5076a392
FC
2122get-magic is not processed. It has been corrected.
2123
41e29def 2124=head3 L<perlvar> revamp
5076a392 2125
41e29def 2126L<perlvar> reorders the variables and groups them by topic. Each variable
5076a392 2127introduced after Perl 5.000 notes the first version in which it is
41e29def 2128available. L<perlvar> also has a new section for deprecated variables to
5076a392
FC
2129note when they were removed.
2130
41e29def 2131=head3 Array and hash slices in scalar context
5076a392 2132
41e29def 2133These are now documented in L<perldata>.
5076a392 2134
41e29def 2135=head3 C<use locale> and formats
5076a392
FC
2136
2137L<perlform> and L<perllocale> have been corrected to state that
2138C<use locale> affects formats.
2139
5076a392
FC
2140=head3 L<overload>
2141
5076a392
FC
2142L<overload>'s documentation has practically undergone a rewrite. It
2143is now much more straightforward and clear.
2144
41e29def 2145=head3 L<perlhack> and perlrepository revamp
5076a392
FC
2146
2147The L<perlhack> and perlrepository documents have been heavily edited and
2148split up into several new documents.
2149
2150The L<perlhack> document is now much shorter, and focuses on the Perl 5
2151development process and submitting patches to Perl. The technical content has
2152been moved to several new documents, L<perlsource>, L<perlinterp>,
2153L<perlhacktut>, and L<perlhacktips>. This technical content has only been
2154lightly edited.
2155
2156The perlrepository document has been renamed to L<perlgit>. This new document
2157is just a how-to on using git with the Perl source code. Any other content
2158that used to be in perlrepository has been moved to perlhack.
2159
41e29def 2160=head3 Time::Piece examples
5076a392
FC
2161
2162Examples in L<perlfaq4> have been updated to show the use of
41e29def 2163L<Time::Piece>.
5076a392
FC
2164
2165=head1 Diagnostics
2166
2167The following additions or changes have been made to diagnostic output,
2168including warnings and fatal error messages. For the complete list of
2169diagnostic messages, see L<perldiag>.
2170
2171=head2 New Diagnostics
2172
a593b319
FC
2173=head3 New Errors
2174
5076a392
FC
2175=over
2176
a593b319 2177=item Closure prototype called
5076a392 2178
a593b319
FC
2179This error occurs when a subroutine reference passed to an attribute
2180handler is called, if the subroutine is a closure [perl #68560].
5076a392 2181
a593b319 2182=item Insecure user-defined property %s
5076a392 2183
a593b319
FC
2184Perl detected tainted data when trying to compile a regular
2185expression that contains a call to a user-defined character property
2186function, i.e. C<\p{IsFoo}> or C<\p{InFoo}>.
2187See L<perlunicode/User-Defined Character Properties> and L<perlsec>.
5076a392 2188
a593b319 2189=item panic: gp_free failed to free glob pointer - something is repeatedly re-creating entries
5076a392 2190
a593b319
FC
2191This new error is triggered if a destructor called on an object in a
2192typeglob that is being freed creates a new typeglob entry containing an
2193object with a destructor that creates a new entry containing an object....
5076a392 2194
a593b319 2195=item Parsing code internal error (%s)
5076a392 2196
a593b319
FC
2197This new fatal error is produced when parsing
2198code supplied by an extension violates the
2199parser's API in a detectable way.
5076a392 2200
a593b319 2201=item refcnt: fd %d%s
5076a392 2202
a593b319
FC
2203This new error only occurs if a internal consistency check fails when a
2204pipe is about to be closed.
5076a392 2205
a593b319 2206=item Regexp modifier "/%c" may not appear twice
5076a392 2207
a593b319
FC
2208The regular expression pattern has one of the
2209mutually exclusive modifiers repeated.
5076a392 2210
a593b319 2211=item Regexp modifiers "/%c" and "/%c" are mutually exclusive
5076a392 2212
a593b319
FC
2213The regular expression pattern has more than one of the mutually
2214exclusive modifiers.
5076a392 2215
a593b319 2216=item Using !~ with %s doesn't make sense
5076a392 2217
a593b319 2218This error occurs when C<!~> is used with C<s///r> or C<y///r>.
5076a392 2219
a593b319 2220=back
5076a392 2221
a593b319 2222=head3 New Warnings
5076a392 2223
a593b319 2224=over
5076a392 2225
a593b319 2226=item "\b{" is deprecated; use "\b\{" instead
5076a392 2227
a593b319 2228=item "\B{" is deprecated; use "\B\{" instead
5076a392 2229
a593b319
FC
2230Use of an unescaped "{" immediately following a C<\b> or C<\B> is now
2231deprecated so as to reserve its use for Perl itself in a future release.
5076a392 2232
a593b319 2233=item Operation "%s" returns its argument for ...
5076a392 2234
a593b319
FC
2235Performing an operation requiring Unicode semantics (such as case-folding)
2236on a Unicode surrogate or a non-Unicode character now triggers a warning:
2237'Operation "%s" returns its argument for ...'.
5076a392 2238
a593b319
FC
2239=item Use of qw(...) as parentheses is deprecated
2240
2241See L</"Use of qw(...) as parentheses">, above, for details.
5076a392
FC
2242
2243=back
2244
2245=head2 Changes to Existing Diagnostics
2246
2247=over 4
2248
2249=item *
2250
4ed2cea4
FC
2251The "Variable $foo is not imported" warning that precedes a
2252C<strict 'vars'> error has now been assigned the "misc" category, so that
2253C<no warnings> will suppress it [perl #73712].
2254
2255=item *
2256
5076a392
FC
2257C<warn> and C<die> now produce 'Wide character' warnings when fed a
2258character outside the byte range if STDERR is a byte-sized handle.
2259
2260=item *
2261
2262The 'Layer does not match this perl' error message has been replaced with
a593b319 2263these more helpful messages [perl #73754]:
5076a392
FC
2264
2265=over 4
2266
2267=item *
2268
2269PerlIO layer function table size (%d) does not match size expected by this
2270perl (%d)
2271
2272=item *
2273
2274PerlIO layer instance size (%d) does not match size expected by this perl
2275(%d)
2276
2277=back
2278
5076a392
FC
2279=item *
2280
2281The "Found = in conditional" warning that is emitted when a constant is
2282assigned to a variable in a condition is now withheld if the constant is
2283actually a subroutine or one generated by C<use constant>, since the value
2284of the constant may not be known at the time the program is written
2285[perl #77762].
2286
2287=item *
2288
2289Previously, if none of the C<gethostbyaddr>, C<gethostbyname> and
2290C<gethostent> functions were implemented on a given platform, they would
2291all die with the message 'Unsupported socket function "gethostent" called',
2292with analogous messages for C<getnet*> and C<getserv*>. This has been
2293corrected.
2294
2295=item *
2296
a593b319
FC
2297The warning message about unrecognized regular expression escapes passed
2298through has been changed to include any literal '{' following the
2299two-character escape. E.g., "\q{" is now emitted instead of "\q".
5076a392
FC
2300
2301=back
2302
2303=head1 Utility Changes
2304
0b88cc74 2305=head3 L<perlbug>
5076a392
FC
2306
2307=over 4
2308
2309=item *
2310
0b88cc74
FC
2311L<perlbug> now looks in the EMAIL environment variable for a return address
2312if the REPLY-TO and REPLYTO variables are empty.
5076a392
FC
2313
2314=item *
2315
0b88cc74
FC
2316L<perlbug> did not previously generate a From: header, potentially
2317resulting in dropped mail. Now it does include that header.
5076a392
FC
2318
2319=item *
2320
0b88cc74 2321The user's address is now used as the return-path.
4ed2cea4 2322
0b88cc74
FC
2323Many systems these days don't have a valid Internet domain name and
2324perlbug@perl.org does not accept email with a return-path that does
2325not resolve. So the user's address is now passed to sendmail so it's
2326less likely to get stuck in a mail queue somewhere [perl #82996].
5076a392 2327
2c389f6c
FC
2328=item *
2329
d430b8e7
FC
2330L<perlbug> now always gives the reporter a chance to change the email
2331address it guesses for them (5.12.2).
2332
2333=item *
2334
2335L<perlbug> should no longer warn about uninitialized values when using the C<-d>
2336and C<-v> options (5.12.2).
2c389f6c 2337
5076a392
FC
2338=back
2339
0b88cc74 2340=head3 L<perl5db.pl>
5076a392 2341
0b88cc74 2342=over
5076a392
FC
2343
2344=item *
2345
0b88cc74
FC
2346The remote terminal works after forking and spawns new sessions - one
2347for each forked process.
5076a392
FC
2348
2349=back
2350
0b88cc74 2351=head3 L<ptargrep>
5076a392
FC
2352
2353=over 4
2354
2355=item *
2356
0b88cc74
FC
2357L<ptargrep> is a new utility to apply pattern matching to the contents of
2358files in a tar archive. It comes with C<Archive::Tar>.
5076a392
FC
2359
2360=back
2361
2362=head1 Configuration and Compilation
2363
61752d82
FC
2364See also L</"Naming fixes in Policy_sh.SH may invalidate Policy.sh">,
2365above.
2366
5076a392
FC
2367=over 4
2368
2369=item *
2370
87595b22
FC
2371CCINCDIR and CCLIBDIR for the mingw64
2372cross-compiler are now correctly under
5076a392
FC
2373$(CCHOME)\mingw\include and \lib rather than immediately below $(CCHOME).
2374
5076a392
FC
2375This means the 'incpath', 'libpth', 'ldflags', 'lddlflags' and
2376'ldflags_nolargefiles' values in Config.pm and Config_heavy.pl are now
87595b22 2377set correctly.
5076a392
FC
2378
2379=item *
2380
87595b22
FC
2381'make test.valgrind' has been adjusted to account for cpan/dist/ext
2382separation.
5076a392
FC
2383
2384=item *
2385
2386On compilers that support it, C<-Wwrite-strings> is now added to cflags by
2387default.
2388
2389=item *
2390
2391The C<Encode> module can now (once again) be included in a static Perl
2392build. The special-case handling for this situation got broken in Perl
23935.11.0, and has now been repaired.
2394
1e463951
FC
2395=item *
2396
2397The previous default size of a PerlIO buffer (4096 bytes) has been increased
2398to the larger of 8192 bytes and your local BUFSIZ. Benchmarks show that doubling
2399this decade-old default increases read and write performance in the neighborhood
2400of 25% to 50% when using the default layers of perlio on top of unix. To choose
2401a non-default size, such as to get back the old value or to obtain an even
2402larger value, configure with:
2403
2404 ./Configure -Accflags=-DPERLIOBUF_DEFAULT_BUFSIZ=N
2405
2406where N is the desired size in bytes; it should probably be a multiple of
2407your page size.
2408
d430b8e7
FC
2409=item *
2410
2411An "incompatible operand types" error in ternary expressions when building
2412with C<clang> has been fixed (5.12.2).
2413
2414=item *
2415
2416Perl now skips setuid C<File::Copy> tests on partitions it detects to be mounted
2417as C<nosuid> (5.12.2).
2418
5076a392
FC
2419=back
2420
5076a392
FC
2421=head1 Platform Support
2422
5076a392
FC
2423=head2 New Platforms
2424
5076a392
FC
2425=over 4
2426
2427=item AIX
2428
cdc10f43 2429Perl now builds on AIX 4.2 (5.12.1).
5076a392
FC
2430
2431=back
2432
2433=head2 Discontinued Platforms
2434
2435=over 4
2436
5076a392
FC
2437=item Apollo DomainOS
2438
2439The last vestiges of support for this platform have been excised from the
2440Perl distribution. It was officially discontinued in version 5.12.0. It had
2441not worked for years before that.
2442
2443=item MacOS Classic
2444
2445The last vestiges of support for this platform have been excised from the
2446Perl distribution. It was officially discontinued in an earlier version.
2447
2448=back
2449
2450=head2 Platform-Specific Notes
2451
d430b8e7
FC
2452=head3 AIX
2453
2454=over
2455
2456=item *
2457
2458F<README.aix> has been updated with information about the XL C/C++ V11 compiler
2459suite (5.12.2).
2460
2461=back
2462
2463=head3 ARM
2464
2465=over
2466
2467=item *
2468
2469The C<d_u32align> configuration probe on ARM has been fixed (5.12.2).
2470
2471=back
2472
554003a2 2473=head3 Cygwin
5076a392
FC
2474
2475=over 4
2476
2477=item *
2478
554003a2 2479MakeMaker has been updated to build man pages on cygwin.
5076a392
FC
2480
2481=item *
2482
554003a2
FC
2483Improved rebase behaviour
2484
2485If a dll is updated on cygwin the old imagebase address is reused.
2486This solves most rebase errors, especially when updating on core dll's.
2487See L<http://www.tishler.net/jason/software/rebase/rebase-2.4.2.README> for more information.
5076a392
FC
2488
2489=item *
2490
554003a2 2491Support for the standard cygwin dll prefix, which is e.g. needed for FFI's
5076a392
FC
2492
2493=item *
2494
554003a2 2495Updated build hints file
5076a392
FC
2496
2497=back
2498
cdc10f43
FC
2499=head3 FreeBSD 7
2500
2501=over
2502
2503=item *
2504
2505FreeBSD 7 no longer contains F</usr/bin/objformat>. At build time,
2506Perl now skips the F<objformat> check for versions 7 and higher and
2507assumes ELF (5.12.1).
2508
2509=back
2510
2511=head3 HP-UX
2512
2513=over
2514
2515=item *
2516
2517Perl now allows -Duse64bitint without promoting to use64bitall on HP-UX
2518(5.12.1).
2519
2520=back
2521
554003a2 2522=head3 IRIX
5076a392
FC
2523
2524Conversion of strings to floating-point numbers is now more accurate on
2525IRIX systems [perl #32380].
2526
554003a2 2527=head3 Mac OS X
5076a392
FC
2528
2529Early versions of Mac OS X (Darwin) had buggy implementations of the
2530C<setregid>, C<setreuid>, C<setrgid> and C<setruid> functions, so perl
2531would pretend they did not exist.
2532
2533These functions are now recognised on Mac OS 10.5 (Leopard; Darwin 9) and
2534higher, as they have been fixed [perl #72990].
2535
554003a2 2536=head3 MirBSD
5076a392 2537
554003a2
FC
2538Previously if you built perl with a shared libperl.so on MirBSD (the
2539default config), it would work up to the installation; however, once
2540installed, it would be unable to find libperl. So path handling is now
2541treated as in the other BSD dialects.
5076a392 2542
554003a2 2543=head3 NetBSD
5076a392 2544
554003a2
FC
2545The NetBSD hints file has been changed to make the system's malloc the
2546default.
5076a392 2547
554003a2 2548=head3 Recent OpenBSDs now use perl's malloc
5076a392 2549
554003a2
FC
2550OpenBSD E<gt> 3.7 has a new malloc implementation which is mmap-based
2551and as such can release memory back to the OS; however, perl's use of
2552this malloc causes a substantial slowdown so we now default to using
2553perl's malloc instead [perl #75742].
5076a392 2554
554003a2 2555=head3 OpenVOS
5076a392 2556
554003a2 2557perl now builds again with OpenVOS (formerly known as Stratus VOS)
5a553547 2558[perl #78132] (5.12.3).
5076a392 2559
554003a2 2560=head3 Solaris
5076a392 2561
554003a2 2562DTrace is now supported on Solaris. There used to be build failures, but
5a553547 2563these have been fixed [perl #73630] (5.12.3).
5076a392 2564
554003a2 2565=head3 VMS
5076a392
FC
2566
2567=over
2568
2569=item *
2570
cdc10f43
FC
2571It's now possible to build extensions on older (pre 7.3-2) VMS systems.
2572
2573DCL symbol length was limited to 1K up until about seven years or
2574so ago, but there was no particularly deep reason to prevent those
2575older systems from configuring and building Perl (5.12.1).
2576
2577=item *
2578
2579We fixed the previously-broken C<-Uuseperlio> build on VMS.
2580
2581We were checking a variable that doesn't exist in the non-default
2582case of disabling perlio. Now we only look at it when it exists (5.12.1).
2583
2584=item *
2585
2586We fixed the -Uuseperlio command-line option in configure.com.
2587
2588Formerly it only worked if you went through all the questions
2589interactively and explicitly answered no (5.12.1).
2590
2591=item *
2592
554003a2 2593C<PerlIOUnix_open> now honours the default permissions on VMS.
5076a392 2594
554003a2
FC
2595When C<perlio> became the default and C<unixio> became the default bottom layer,
2596the most common path for creating files from Perl became C<PerlIOUnix_open>,
2597which has always explicitly used C<0666> as the permission mask.
5076a392 2598
554003a2
FC
2599To avoid this, C<0777> is now passed as the permissions to C<open()>. In the
2600VMS CRTL, C<0777> has a special meaning over and above intersecting with the
2601current umask; specifically, it allows Unix syscalls to preserve native default
5a553547
FC
2602permissions (5.12.3).
2603
2604=item *
2605
2606Spurious record boundaries are no longer
2607introduced by the PerlIO layer during output (5.12.3).
5076a392
FC
2608
2609=item *
2610
554003a2
FC
2611The shortening of symbols longer than 31 characters in the C sources is
2612now done by the compiler rather than by xsubpp (which could only do so
2613for generated symbols in XS code).
5076a392
FC
2614
2615=item *
2616
554003a2
FC
2617Record-oriented files (record format variable or variable with fixed control)
2618opened for write by the perlio layer will now be line-buffered to prevent the
2619introduction of spurious line breaks whenever the perlio buffer fills up.
5076a392 2620
d430b8e7
FC
2621=item *
2622
2623F<git_version.h> is now installed on VMS. This was an oversight in v5.12.0 which
2624caused some extensions to fail to build (5.12.2).
2625
2626=item *
2627
2628Several memory leaks in L<stat()|perlfunc/"stat FILEHANDLE"> have been fixed (5.12.2).
2629
2630=item *
2631
2632A memory leak in C<Perl_rename()> due to a double allocation has been
2633fixed (5.12.2).
2634
2635=item *
2636
2637A memory leak in C<vms_fid_to_name()> (used by C<realpath()> and
2638C<realname()>) has been fixed (5.12.2).
2639
5076a392
FC
2640=back
2641
554003a2 2642=head3 Windows
5076a392 2643
5a1f7719
FC
2644See also L</"fork() emulation will not wait for signalled children"> and
2645L</"Perl source code is read in text mode on Windows">, above.
2646
5076a392
FC
2647=over 4
2648
2649=item *
2650
554003a2 2651Fixed build process for SDK2003SP1 compilers.
5076a392 2652
554003a2 2653=item *
5076a392 2654
01b1a9e4
FC
2655Compilation with Visual Studio 2010 is now supported.
2656
2657=item *
2658
554003a2
FC
2659When using old 32-bit compilers, the define C<_USE_32BIT_TIME_T> will now
2660be set in C<$Config{ccflags}>. This improves portability when compiling
2661XS extensions using new compilers, but for a perl compiled with old 32-bit
2662compilers.
5076a392
FC
2663
2664=item *
2665
554003a2
FC
2666C<$Config{gccversion}> is now set correctly when perl is built using the
2667mingw64 compiler from L<http://mingw64.org> [perl #73754].
5076a392 2668
554003a2
FC
2669=item *
2670
d430b8e7
FC
2671When building Perl with the mingw64 x64 cross-compiler C<incpath>,
2672C<libpth>, C<ldflags>, C<lddlflags> and C<ldflags_nolargefiles> values
2673in F<Config.pm> and F<Config_heavy.pl> were not previously being set
2674correctly because, with that compiler, the include and lib directories
2675are not immediately below C<$(CCHOME)> (5.12.2).
2676
2677=item *
2678
554003a2
FC
2679The build process proceeds more smoothly with mingw and dmake when
2680F<C:\MSYS\bin> is in the PATH, due to a C<Cwd> fix.
5076a392
FC
2681
2682=item *
2683
554003a2
FC
2684Support for building with Visual C++ 2010 is now underway, but is not yet
2685complete. See F<README.win32> or L<perlwin32> for more details.
5076a392 2686
554003a2
FC
2687=item *
2688
2689The option to use an externally-supplied C<crypt()>, or to build with no
2690C<crypt()> at all, has been removed. Perl supplies its own C<crypt()>
2691implementation for Windows, and the political situation that required
2692this part of the distribution to sometimes be omitted is long gone.
5076a392
FC
2693
2694=back
2695
2696=head1 Internal Changes
2697
1e463951 2698=head2 New APIs
5076a392 2699
1e463951 2700=head3 CLONE_PARAMS structure added to ease correct thread creation
5076a392 2701
1e463951
FC
2702Modules that create threads should now create C<CLONE_PARAMS> structures
2703by calling the new function C<Perl_clone_params_new()>, and free them with
2704C<Perl_clone_params_del()>. This will ensure compatibility with any future
2705changes to the internals of the C<CLONE_PARAMS> structure layout, and that
2706it is correctly allocated and initialised.
5076a392 2707
1e463951 2708=head3 New parsing functions
5076a392 2709
1e463951
FC
2710Several functions have been added for parsing statements or multiple
2711statements:
5076a392 2712
1e463951 2713=over
5076a392
FC
2714
2715=item *
2716
1e463951 2717C<parse_fullstmt> parses a complete Perl statement.
5076a392
FC
2718
2719=item *
2720
1e463951
FC
2721C<parse_stmtseq> parses a sequence of statements, up
2722to closing brace or EOF.
5076a392
FC
2723
2724=item *
2725
1e463951 2726C<parse_block> parses a block [perl #78222].
5076a392
FC
2727
2728=item *
2729
1e463951
FC
2730C<parse_barestmt> parses a statement
2731without a label.
5076a392
FC
2732
2733=item *
2734
1e463951 2735C<parse_label> parses a statement label, separate from statements.
5076a392 2736
1e463951 2737=back
5076a392 2738
1e463951
FC
2739The
2740L<C<parse_fullexpr()>|perlapi/parse_fullexpr>,
2741L<C<parse_listexpr()>|perlapi/parse_listexpr>,
2742L<C<parse_termexpr()>|perlapi/parse_termexpr>, and
2743L<C<parse_arithexpr()>|perlapi/parse_arithexpr>
2744functions have been added to the API. They perform
2745recursive-descent parsing of expressions at various precedence levels.
2746They are expected to be used by syntax plugins.
5076a392 2747
1e463951 2748See L<perlapi> for details.
5076a392 2749
1e463951 2750=head3 Hints hash API
5076a392 2751
1e463951
FC
2752A new C API for introspecting the hinthash C<%^H> at runtime has been
2753added. See C<cop_hints_2hv>, C<cop_hints_fetchpvn>, C<cop_hints_fetchpvs>,
2754C<cop_hints_fetchsv>, and C<hv_copy_hints_hv> in L<perlapi> for details.
5076a392 2755
1e463951
FC
2756A new, experimental API has been added for accessing the internal
2757structure that Perl uses for C<%^H>. See the functions beginning with
2758C<cophh_> in L<perlapi>.
5076a392 2759
1e463951 2760=head3 C interface to C<caller()>
5076a392 2761
1e463951
FC
2762The C<caller_cx> function has been added as an XSUB-writer's equivalent of
2763C<caller()>. See L<perlapi> for details.
5076a392 2764
1e463951 2765=head3 Custom per-subroutine check hooks
5076a392 2766
1e463951
FC
2767XS code in an extension module can now annotate a subroutine (whether
2768implemented in XS or in Perl) so that nominated XS code will be called
2769at compile time (specifically as part of op checking) to change the op
2770tree of that subroutine. The compile-time check function (supplied by
2771the extension module) can implement argument processing that can't be
2772expressed as a prototype, generate customised compile-time warnings,
2773perform constant folding for a pure function, inline a subroutine
2774consisting of sufficiently simple ops, replace the whole call with a
2775custom op, and so on. This was previously all possible by hooking the
2776C<entersub> op checker, but the new mechanism makes it easy to tie the
2777hook to a specific subroutine. See L<perlapi/cv_set_call_checker>.
5076a392 2778
1e463951
FC
2779To help in writing custom check hooks, several subtasks within standard
2780C<entersub> op checking have been separated out and exposed in the API.
5076a392 2781
1e463951 2782=head3 Improved support for custom OPs
5076a392 2783
1e463951
FC
2784Custom ops can now be registered with the new C<custom_op_register> C
2785function and the C<XOP> structure. This will make it easier to add new
2786properties of custom ops in the future. Two new properties have been added
2787already, C<xop_class> and C<xop_peep>.
5076a392 2788
1e463951
FC
2789C<xop_class> is one of the OA_*OP constants, and allows L<B> and other
2790introspection mechanisms to work with custom ops
2791that aren't BASEOPs. C<xop_peep> is a pointer to
2792a function that will be called for ops of this
2793type from C<Perl_rpeep>.
5076a392 2794
1e463951
FC
2795See L<perlguts/Custom Operators> and L<perlapi/Custom Operators> for more
2796detail.
5076a392 2797
1e463951
FC
2798The old C<PL_custom_op_names>/C<PL_custom_op_descs> interface is still
2799supported but discouraged.
5076a392 2800
1e463951 2801=head3 Scope hooks
5076a392 2802
1e463951
FC
2803It is now possible for XS code to hook into Perl's lexical scope
2804mechanism at compile time, using the new C<Perl_blockhook_register>
2805function. See L<perlguts/"Compile-time scope hooks">.
5076a392 2806
1e463951 2807=head3 The recursive part of the peephole optimizer is now hookable
5076a392
FC
2808
2809In addition to C<PL_peepp>, for hooking into the toplevel peephole optimizer, a
2810C<PL_rpeepp> is now available to hook into the optimizer recursing into
2811side-chains of the optree.
2812
1e463951 2813=head3 New non-magical variants of existing functions
5076a392 2814
1e463951
FC
2815The following functions/macros have been added to the API. The C<*_nomg>
2816macros are equivalent to their non-_nomg variants, except that they ignore
2817get-magic. Those ending in C<_flags> allow one to specify whether
2818get-magic is processed.
5076a392 2819
1e463951
FC
2820 sv_2bool_flags
2821 SvTRUE_nomg
2822 sv_2nv_flags
2823 SvNV_nomg
2824 sv_cmp_flags
2825 sv_cmp_locale_flags
2826 sv_eq_flags
2827 sv_collxfrm_flags
5076a392 2828
1e463951 2829In some of these cases, the non-_flags functions have
5076a392
FC
2830been replaced with wrappers around the new functions.
2831
1e463951 2832=head3 pv/pvs/sv versions of existing functions
5076a392 2833
1e463951 2834Many functions ending with pvn now have equivalent pv/pvs/sv versions.
5076a392 2835
1e463951 2836=head3 List op-building functions
5076a392 2837
1e463951
FC
2838List op-building functions have been added to the
2839API. See L<op_append_elem|perlapi/op_append_elem>,
2840L<op_append_list|perlapi/op_append_list>, and
2841L<op_prepend_elem|perlapi/op_prepend_elem> in L<perlapi>.
5076a392 2842
1e463951 2843=head3 C<LINKLIST>
5076a392 2844
1e463951
FC
2845The L<LINKLIST|perlapi/LINKLIST> macro, part of op building that
2846constructs the execution-order op chain, has been added to the API.
5076a392 2847
1e463951 2848=head3 Localisation functions
5076a392 2849
1e463951
FC
2850The C<save_freeop>, C<save_op>, C<save_pushi32ptr> and C<save_pushptrptr>
2851functions have been added to the API.
5076a392 2852
1e463951 2853=head3 Stash names
5076a392 2854
1e463951
FC
2855A stash can now have a list of effective names in addition to its usual
2856name. The first effective name can be accessed via the C<HvENAME> macro,
2857which is now the recommended name to use in MRO linearisations (C<HvNAME>
2858being a fallback if there is no C<HvENAME>).
5076a392 2859
1e463951
FC
2860These names are added and deleted via C<hv_ename_add> and
2861C<hv_ename_delete>. These two functions are I<not> part of the API.
5076a392 2862
1e463951 2863=head3 New functions for finding and removing magic
5076a392 2864
1e463951
FC
2865The L<C<mg_findext()>|perlapi/mg_findext> and
2866L<C<sv_unmagicext()>|perlapi/sv_unmagicext>
2867functions have been added to the API.
2868They allow extension authors to find and remove magic attached to
2869scalars based on both the magic type and the magic virtual table, similar to how
2870C<sv_magicext()> attaches magic of a certain type and with a given virtual table
2871to a scalar. This eliminates the need for extensions to walk the list of
2872C<MAGIC> pointers of an C<SV> to find the magic that belongs to them.
5076a392 2873
1e463951 2874=head3 C<find_rundefsv>
5076a392 2875
1e463951
FC
2876This function returns the SV representing C<$_>, whether it's lexical
2877or dynamic.
5076a392 2878
1e463951 2879=head3 C<Perl_croak_no_modify>
5076a392 2880
1e463951
FC
2881C<Perl_croak_no_modify()> is short-hand for
2882C<Perl_croak("%s", PL_no_modify)>.
5076a392 2883
1e463951 2884=head3 C<PERL_STATIC_INLINE> define
5076a392 2885
1e463951
FC
2886The C<PERL_STATIC_INLINE> define has been added to provide the best-guess
2887incantation to use for static inline functions, if the C compiler supports
2888C99-style static inline. If it doesn't, it'll give a plain C<static>.
5076a392 2889
1e463951
FC
2890C<HAS_STATIC_INLINE> can be used to check if the compiler actually supports
2891inline functions.
5076a392 2892
1e463951 2893=head3 New C<pv_escape> option for hexadecimal escapes
5076a392 2894
1e463951
FC
2895A new option, C<PERL_PV_ESCAPE_NONASCII>, has been added to C<pv_escape> to
2896dump all characters above ASCII in hexadecimal. Before, one could get all
2897characters as hexadecimal or the Latin1 non-ASCII as octal.
5076a392 2898
1e463951 2899=head3 C<lex_start>
5076a392 2900
1e463951 2901C<lex_start> has been added to the API, but is considered experimental.
5076a392 2902
1e463951 2903=head3 C<op_scope()> and C<op_lvalue()>
5076a392 2904
1e463951
FC
2905The C<op_scope()> and C<op_lvalue()> functions have been added to the API,
2906but are considered experimental.
5076a392 2907
1e463951 2908=head2 C API Changes
5076a392 2909
1e463951 2910=head3 C<PERL_POLLUTE> has been removed
5076a392 2911
1e463951
FC
2912The option to define C<PERL_POLLUTE> to expose older 5.005 symbols for
2913backwards compatibility has been removed. It's use was always discouraged,
2914and MakeMaker contains a more specific escape hatch:
5076a392 2915
1e463951 2916 perl Makefile.PL POLLUTE=1
5076a392 2917
1e463951
FC
2918This can be used for modules that have not been upgraded to 5.6 naming
2919conventions (and really should be completely obsolete by now).
5076a392 2920
1e463951 2921=head3 Check API compatibility when loading XS modules
5076a392 2922
1e463951
FC
2923When perl's API changes in incompatible ways (which usually happens between
2924major releases), XS modules compiled for previous versions of perl will not
2925work anymore. They will need to be recompiled against the new perl.
5076a392 2926
1e463951
FC
2927In order to ensure that modules are recompiled, and to prevent users from
2928accidentally loading modules compiled for old perls into newer ones, the
2929C<XS_APIVERSION_BOOTCHECK> macro has been added. That macro, which is
2930called when loading every newly compiled extension, compares the API
2931version of the running perl with the version a module has been compiled for
2932and raises an exception if they don't match.
5076a392 2933
1e463951 2934=head3 Perl_fetch_cop_label
5076a392 2935
1e463951
FC
2936The first argument of the C API function C<Perl_fetch_cop_label> has changed
2937from C<struct refcounted he *> to C<COP *>, to insulate the user from
2938implementation details.
5076a392 2939
1e463951
FC
2940This API function was marked as "may change", and likely isn't in use outside
2941the core. (Neither an unpacked CPAN, nor Google's codesearch, finds any other
2942references to it.)
5076a392 2943
1e463951 2944=head3 GvCV() and GvGP() are no longer lvalues
5076a392 2945
1e463951
FC
2946The new GvCV_set() and GvGP_set() macros are now provided to replace
2947assignment to those two macros.
5076a392 2948
1e463951
FC
2949This allows a future commit to eliminate some backref magic between GV
2950and CVs, which will require complete control over assignment to the
2951gp_cv slot.
5076a392 2952
1e463951 2953=head3 CvGV() is no longer an lvalue
5076a392 2954
1e463951
FC
2955Under some circumstances, the C<CvGV()> field of a CV is now
2956reference-counted. To ensure consistent behaviour, direct assignment to
2957it, for example C<CvGV(cv) = gv> is now a compile-time error. A new macro,
2958C<CvGV_set(cv,gv)> has been introduced to perform this operation
2959safely. Note that modification of this field is not part of the public
2960API, regardless of this new macro (and despite its being listed in this section).
5076a392 2961
1e463951 2962=head3 CvSTASH() is no longer an lvalue
5076a392 2963
1e463951
FC
2964The C<CvSTASH()> macro can now only be used as an rvalue. C<CvSTASH_set()>
2965has been added to replace assignment to C<CvSTASH()>. This is to ensure
2966that backreferences are handled properly. These macros are not part of the
2967API.
5076a392 2968
1e463951 2969=head3 Calling conventions for C<newFOROP> and C<newWHILEOP>
5076a392 2970
1e463951
FC
2971The way the parser handles labels has been cleaned up and refactored. As a
2972result, the C<newFOROP()> constructor function no longer takes a parameter
2973stating what label is to go in the state op.
5076a392 2974
1e463951
FC
2975The C<newWHILEOP()> and C<newFOROP()> functions no longer accept a line
2976number as a parameter.
5076a392 2977
1e463951 2978=head3 Flags passed to C<uvuni_to_utf8_flags> and C<utf8n_to_uvuni>
5076a392 2979
1e463951
FC
2980Some of the flags parameters to uvuni_to_utf8_flags() and
2981utf8n_to_uvuni() have changed. This is a result of Perl's now allowing
5076a392
FC
2982internal storage and manipulation of code points that are problematic
2983in some situations. Hence, the default actions for these functions has
2984been complemented to allow these code points. The new flags are
2985documented in L<perlapi>. Code that requires the problematic code
483b16f3 2986points to be rejected needs to change to use the new flags. Some flag
5076a392
FC
2987names are retained for backward source compatibility, though they do
2988nothing, as they are now the default. However the flags
2989C<UNICODE_ALLOW_FDD0>, C<UNICODE_ALLOW_FFFF>, C<UNICODE_ILLEGAL>, and
2990C<UNICODE_IS_ILLEGAL> have been removed, as they stem from a
2991fundamentally broken model of how the Unicode non-character code points
2992should be handled, which is now described in
2993L<perlunicode/Non-character code points>. See also L</Selected Bug Fixes>.
2994
1e463951 2995XXX Which bugs in particular? Selected Bug Fixes is too long for this link
483b16f3
KW
2996to be meaningful right now
2997I don't see the bugs in that section currently -- khw
5076a392 2998
1e463951 2999=head2 Deprecated C APIs
5076a392 3000
1e463951 3001=over
5076a392 3002
1e463951 3003=item C<Perl_ptr_table_clear>
5076a392 3004
1e463951
FC
3005C<Perl_ptr_table_clear> is no longer part of Perl's public API. Calling it
3006now generates a deprecation warning, and it will be removed in a future
3007release.
5076a392 3008
1e463951 3009=item C<sv_compile_2op>
5076a392 3010
1e463951
FC
3011The C<sv_compile_2op()> API function is now deprecated. Searches suggest
3012that nothing on CPAN is using it, so this should have zero impact.
5076a392 3013
1e463951
FC
3014It attempted to provide an API to compile code down to an optree, but failed
3015to bind correctly to lexicals in the enclosing scope. It's not possible to
3016fix this problem within the constraints of its parameters and return value.
5076a392 3017
1e463951 3018=item C<find_rundefsvoffset>
5076a392 3019
1e463951
FC
3020The C<find_rundefsvoffset> function has been deprecated. It appeared that
3021its design was insufficient for reliably getting the lexical C<$_> at
3022run-time.
5076a392 3023
1e463951
FC
3024Use the new C<find_rundefsv> function or the C<UNDERBAR> macro
3025instead. They directly return the right SV representing C<$_>, whether it's
3026lexical or dynamic.
5076a392 3027
1e463951 3028=item C<CALL_FPTR> and C<CPERLscope>
5076a392 3029
1e463951
FC
3030Those are left from an old implementation of C<MULTIPLICITY> using C++ objects,
3031which was removed in Perl 5.8. Nowadays these macros do exactly nothing, so
3032they shouldn't be used anymore.
5076a392 3033
1e463951
FC
3034For compatibility, they are still defined for external C<XS> code. Only
3035extensions defining C<PERL_CORE> must be updated now.
5076a392 3036
1e463951 3037=back
5076a392 3038
1e463951 3039=head2 Other Internal Changes
5076a392 3040
1e463951 3041=head3 Stack unwinding
5076a392 3042
1e463951
FC
3043The protocol for unwinding the C stack at the last stage of a C<die>
3044has changed how it identifies the target stack frame. This now uses
3045a separate variable C<PL_restartjmpenv>, where previously it relied on
3046the C<blk_eval.cur_top_env> pointer in the C<eval> context frame that
3047has nominally just been discarded. This change means that code running
3048during various stages of Perl-level unwinding no longer needs to take
3049care to avoid destroying the ghost frame.
5076a392 3050
1e463951 3051=head3 Scope stack entries
5076a392 3052
1e463951
FC
3053The format of entries on the scope stack has been changed, resulting in a
3054reduction of memory usage of about 10%. In particular, the memory used by
3055the scope stack to record each active lexical variable has been halved.
5076a392 3056
1e463951 3057=head3 Memory allocation for pointer tables
5076a392 3058
1e463951
FC
3059Memory allocation for pointer tables has been changed. Previously
3060C<Perl_ptr_table_store> allocated memory from the same arena system as
3061C<SV> bodies and C<HE>s, with freed memory remaining bound to those arenas
3062until interpreter exit. Now it allocates memory from arenas private to the
3063specific pointer table, and that memory is returned to the system when
3064C<Perl_ptr_table_free> is called. Additionally, allocation and release are
3065both less CPU intensive.
5076a392 3066
1e463951 3067=head3 C<UNDERBAR>
5076a392 3068
1e463951
FC
3069The C<UNDERBAR> macro now calls C<find_rundefsv>. C<dUNDERBAR> is now a
3070noop but should still be used to ensure past and future compatibility.
5076a392 3071
1e463951 3072=head3 String comparison routines renamed
5076a392 3073
1e463951
FC
3074The ibcmp_* functions have been renamed and are now called foldEQ,
3075foldEQ_locale and foldEQ_utf8. The old names are still available as
3076macros.
3077
3078=head3 C<chop> and C<chomp> implementations merged
3079
3080The opcode bodies for C<chop> and C<chomp> and for C<schop> and C<schomp>
3081have been merged. The implementation functions C<Perl_do_chop()> and
3082C<Perl_do_chomp()>, never part of the public API, have been merged and
3083moved to a static function in F<pp.c>. This shrinks the perl binary
3084slightly, and should not affect any code outside the core (unless it is
3085relying on the order of side effects when C<chomp> is passed a I<list> of
3086values).
5076a392
FC
3087
3088=head1 Selected Bug Fixes
3089
e8e35311
FC
3090=head2 I/O
3091
5076a392
FC
3092=over 4
3093
3094=item *
3095
e8e35311 3096Perl no longer produces this warning:
a593b319
FC
3097
3098 $ perl -we 'open my $f, ">", \my $x; binmode $f, "scalar"'
3099 Use of uninitialized value in binmode at -e line 1.
3100
3101=item *
3102
e8e35311
FC
3103Opening a glob reference via C<< open $fh, "E<gt>", \*glob >> will no longer
3104cause the glob to be corrupted when the filehandle is printed to. This would
3105cause perl to crash whenever the glob's contents were accessed
3106[perl #77492].
4ed2cea4
FC
3107
3108=item *
3109
e8e35311
FC
3110PerlIO no longer crashes when called recursively, e.g., from a signal
3111handler. Now it just leaks memory [perl #75556].
4ed2cea4
FC
3112
3113=item *
3114
e8e35311
FC
3115Most I/O functions were not warning for unopened handles unless the
3116'closed' and 'unopened' warnings categories were both enabled. Now only
3117C<use warnings 'unopened'> is necessary to trigger these warnings (as was
438c239f 3118always meant to be the case).
4ed2cea4
FC
3119
3120=item *
3121
438c239f 3122There have been several fixes to PerlIO layers:
e8e35311 3123
438c239f
FC
3124When C<binmode FH, ":crlf"> pushes the C<:crlf> layer on top of the stack,
3125it no longer enables crlf layers lower in the stack, to avoid unexpected
3126results [perl #38456].
4ed2cea4 3127
438c239f
FC
3128Opening a file in C<:raw> mode now does what it advertises to do (first
3129open the file, then binmode it), instead of simply leaving off the top
3130layer [perl #80764].
5076a392 3131
438c239f
FC
3132The three layers C<:pop>, C<:utf8> and C<:bytes> didn't allow stacking when
3133opening a file. For example
e8e35311 3134this:
5076a392 3135
e8e35311 3136 open FH, '>:pop:perlio', 'some.file' or die $!;
5076a392 3137
438c239f
FC
3138Would throw an error: "Invalid argument". This has been fixed in this
3139release [perl #82484].
5076a392 3140
e8e35311
FC
3141=back
3142
3143=head2 Regular Expression Bug Fixes
3144
3145=over
5076a392
FC
3146
3147=item *
3148
e8e35311
FC
3149The regular expression engine no longer loops when matching
3150C<"\N{LATIN SMALL LIGATURE FF}" =~ /f+/i> and similar expressions
cdc10f43 3151[perl #72998] (5.12.1).
5076a392
FC
3152
3153=item *
3154
e8e35311
FC
3155The trie runtime code should no longer allocate massive amounts of memory,
3156fixing #74484.
5076a392
FC
3157
3158=item *
3159
438c239f
FC
3160Syntax errors in C<< (?{...}) >> blocks no longer cause panic messages
3161[perl #2353].
5076a392
FC
3162
3163=item *
3164
438c239f
FC
3165A pattern like C<(?:(o){2})?> no longer causes a "panic" error
3166[perl #39233].
5076a392
FC
3167
3168=item *
3169
438c239f 3170A fatal error in regular expressions containing C<(.*?)> when processing
d430b8e7 3171UTF-8 data has been fixed [perl #75680] (5.12.2).
5076a392
FC
3172
3173=item *
3174
e8e35311 3175An erroneous regular expression engine optimisation that caused regex verbs like
438c239f 3176C<*COMMIT> sometimes to be ignored has been removed.
5076a392
FC
3177
3178=item *
3179
e8e35311
FC
3180The regular expression bracketed character class C<[\8\9]> was effectively the
3181same as C<[89\000]>, incorrectly matching a NULL character. It also gave
3182incorrect warnings that the C<8> and C<9> were ignored. Now C<[\8\9]> is the
3183same as C<[89]> and gives legitimate warnings that C<\8> and C<\9> are
3184unrecognized escape sequences, passed-through.
5076a392
FC
3185
3186=item *
3187
e8e35311
FC
3188A regular expression match in the right-hand side of a global substitution
3189(C<s///g>) that is in the same scope will no longer cause match variables
3190to have the wrong values on subsequent iterations. This can happen when an
3191array or hash subscript is interpolated in the right-hand side, as in
3192C<s|(.)|@a{ print($1), /./ }|g> [perl #19078].
5076a392
FC
3193
3194=item *
3195
438c239f
FC
3196Several cases in which characters in the Latin-1 non-ASCII range (0x80 to
31970xFF) used not to match themselves or used to match both a character class
3198and its complement have been fixed. For instance, U+00E2 could match both
3199C<\w> and C<\W> [perl #78464] [perl #18281] [perl #60156].
5076a392
FC
3200
3201=item *
3202
e8e35311
FC
3203Matching a Unicode character against an alternation containing characters
3204that happened to match continuation bytes in the former's UTF8
3205representation (C<qq{\x{30ab}} =~ /\xab|\xa9/>) would cause erroneous
3206warnings [perl #70998].
5076a392
FC
3207
3208=item *
3209
e8e35311
FC
3210The trie optimisation was not taking empty groups into account, preventing
3211'foo' from matching C</\A(?:(?:)foo|bar|zot)\z/> [perl #78356].
5076a392
FC
3212
3213=item *
3214
e8e35311
FC
3215A pattern containing a C<+> inside a lookahead would sometimes cause an
3216incorrect match failure in a global match (e.g., C</(?=(\S+))/g>)
3217[perl #68564].
5076a392
FC
3218
3219=item *
3220
e8e35311
FC
3221A regular expression optimisation would sometimes cause a match with a
3222C<{n,m}> quantifier to fail when it should match [perl #79152].
5076a392
FC
3223
3224=item *
3225
e8e35311 3226Case insensitive matching in regular expressions compiled under C<use
438c239f
FC
3227locale> now works much more sanely when the pattern or
3228target string is encoded internally in
3229UTF8. Previously, under these conditions the localeness
e8e35311
FC
3230was completely lost. Now, code points above 255 are treated as Unicode,
3231but code points between 0 and 255 are treated using the current locale
438c239f
FC
3232rules, regardless of whether the pattern or the string is encoded in UTF8.
3233The few case-insensitive matches that cross the 255/256 boundary are not
e8e35311
FC
3234allowed. For example, 0xFF does not caselessly match the character at
32350x178, LATIN CAPITAL LETTER Y WITH DIAERESIS, because 0xFF may not be
3236LATIN SMALL LETTER Y in the current locale, and Perl has no way of
3237knowing if that character even exists in the locale, much less what code
3238point it is.
5076a392
FC
3239
3240=item *
3241
e8e35311
FC
3242The C<(?|...)> regular expression construct no longer crashes if the final
3243branch has more sets of capturing parentheses than any other branch. This
3244was fixed in Perl 5.10.1 for the case of a single branch, but that fix did
3245not take multiple branches into account [perl #84746].
5076a392
FC
3246
3247=item *
3248
e8e35311
FC
3249A bug has been fixed in the implementation of C<{...}> quantifiers in
3250regular expressions that prevented the code block in
3251C</((\w+)(?{ print $2 })){2}/> from seeing the C<$2> sometimes
3252[perl #84294].
5076a392 3253
e8e35311 3254=back
5076a392 3255
e8e35311
FC
3256=head2 Syntax/Parsing Bugs
3257
3258=over
5076a392
FC
3259
3260=item *
3261
e8e35311 3262C<when(scalar){...}> no longer crashes, but produces a syntax error
cdc10f43 3263[perl #74114] (5.12.1).
5076a392
FC
3264
3265=item *
3266
e8e35311
FC
3267A label right before a string eval (C<foo: eval $string>) no longer causes
3268the label to be associated also with the first statement inside the eval
3269[perl #74290] (5.12.1).
5076a392
FC
3270
3271=item *
3272
b2c076b5 3273The C<no 5.13.2;> form of C<no> no longer tries to turn on features or
d430b8e7 3274pragmata (i.e., strict) [perl #70075] (5.12.2).
5076a392
FC
3275
3276=item *
3277
b2c076b5
FC
3278C<BEGIN {require 5.12.0}> now behaves as documented, rather than behaving
3279identically to C<use 5.12.0;>. Previously, C<require> in a C<BEGIN> block
3280was erroneously executing the C<use feature ':5.12.0'> and
3281C<use strict;> behaviour, which only C<use> was documented to
3282provide [perl #69050].
5076a392
FC
3283
3284=item *
3285
5076a392
FC
3286A regression introduced in Perl 5.12.0, making
3287C<< my $x = 3; $x = length(undef) >> result in C<$x> set to C<3> has been
d430b8e7 3288fixed. C<$x> will now be C<undef> [perl #85508] (5.12.2).
b2c076b5
FC
3289
3290=item *
3291
3292When strict 'refs' mode is off, C<%{...}> in rvalue context returns
3293C<undef> if its argument is undefined. An optimisation introduced in perl
32945.12.0 to make C<keys %{...}> faster when used as a boolean did not take
3295this into account, causing C<keys %{+undef}> (and C<keys %$foo> when
3296C<$foo> is undefined) to be an error, which it should only be in strict
3297mode [perl #81750].
5076a392
FC
3298
3299=item *
3300
e8e35311 3301Constant-folding used to cause
5076a392 3302
e8e35311 3303 $text =~ ( 1 ? /phoo/ : /bear/)
5076a392 3304
e8e35311
FC
3305to turn into
3306
3307 $text =~ /phoo/
3308
3309at compile time. Now it correctly matches against C<$_> [perl #20444].
5076a392
FC
3310
3311=item *
3312
e8e35311
FC
3313Parsing Perl code (either with string C<eval> or by loading modules) from
3314within a C<UNITCHECK> block no longer causes the interpreter to crash
3315[perl #70614].
5076a392
FC
3316
3317=item *
3318
b2c076b5
FC
3319String evals no longer fail after 2 billion scopes have been
3320compiled [perl #83364].
3321
3322=item *
3323
e8e35311
FC
3324The parser no longer hangs when encountering certain Unicode characters,
3325such as U+387 [perl #74022].
5076a392
FC
3326
3327=item *
3328
b2c076b5
FC
3329Several contexts no longer allow a Unicode character to begin a word
3330that should never begin words, for an example an accent that must follow
3331another character previously could precede all other characters.
5076a392
FC
3332
3333=item *
3334
e8e35311
FC
3335Defining a constant with the same name as one of perl's special blocks
3336(e.g., INIT) stopped working in 5.12.0, but has now been fixed
3337[perl #78634].
5076a392
FC
3338
3339=item *
3340
e8e35311
FC
3341A reference to a literal value used as a hash key (C<$hash{\"foo"}>) used
3342to be stringified, even if the hash was tied [perl #79178].
5076a392
FC
3343
3344=item *
3345
e8e35311
FC
3346A closure containing an C<if> statement followed by a constant or variable
3347is no longer treated as a constant [perl #63540].
5076a392
FC
3348
3349=item *
3350
e8e35311
FC
3351C<state> can now be used with attributes. It used to mean the same thing as
3352C<my> if attributes were present [perl #68658].
5076a392
FC
3353
3354=item *
3355
e8e35311
FC
3356Expressions like C<< @$a > 3 >> no longer cause C<$a> to be mentioned in
3357the "Use of uninitialized value in numeric gt" warning when C<$a> is
3358undefined (since it is not part of the C<E<gt>> expression, but the operand
3359of the C<@>) [perl #72090].
5076a392
FC
3360
3361=item *
3362
e8e35311
FC
3363Accessing an element of a package array with a hard-coded number (as
3364opposed to an arbitrary expression) would crash if the array did not exist.
3365Usually the array would be autovivified during compilation, but typeglob
3366manipulation could remove it, as in these two cases which used to crash:
5076a392 3367
e8e35311
FC
3368 *d = *a; print $d[0];
3369 undef *d; print $d[0];
5076a392 3370
2c389f6c
FC
3371=item *
3372
3373The C<-C> command line option, when used on the shebang line, can now be
3374followed by other options [perl #72434].
3375
3376=item *
3377
3378The C<B> module was returning C<B::OP>s instead of C<B::LOGOP>s for C<entertry> [perl #80622].
3379This was due to a bug in the perl core, not in C<B> itself.
3380
e8e35311 3381=back
5076a392 3382
e262cb24
FC
3383=head2 Stashes, Globs and Method Lookup
3384
3385Perl 5.10.0 introduced a new internal mechanism for caching MROs (method
3386resolution orders, or lists of parent classes; aka "isa" caches) to make
3387method lookup faster (so @ISA arrays would not have to be searched
3388repeatedly). Unfortunately, this brought with it quite a few bugs. Almost
3389all of these have been fixed now, along with a few MRO-related bugs that
3390existed before 5.10.0:
3391
3392=over
3393
3394=item *
3395
3396The following used to have erratic effects on method resolution, because
3397the "isa" caches were not reset or otherwise ended up listing the wrong
3398classes. These have been fixed.
3399
3400=over
3401
3402=item Aliasing packages by assigning to globs [perl #77358]
3403
3404=item Deleting packages by deleting their containing stash elements
3405
3406=item Undefining the glob containing a package (C<undef *Foo::>)
3407
3408=item Undefining an ISA glob (C<undef *Foo::ISA>)
3409
3410=item Deleting an ISA stash element (C<delete $Foo::{ISA}>)
3411
3412=item Sharing @ISA arrays between classes (via C<*Foo::ISA = \@Bar::ISA> or
3413C<*Foo::ISA = *Bar::ISA>) [perl #77238]
3414
3415=back
3416
3417C<undef *Foo::ISA> would even stop a new C<@Foo::ISA> array from updating
3418caches.
3419
3420=item *
3421
3422Typeglob assignments would crash if the glob's stash no longer existed, so
3423long as the glob assigned to was named 'ISA' or the glob on either side of
3424the assignment contained a subroutine.
3425
3426=item *
3427
3428C<PL_isarev>, which is accessible to Perl via C<mro::get_isarev> is now
3429updated properly when packages are deleted or removed from the C<@ISA> of
3430other classes. This allows many packages to be created and deleted without
3431causing a memory leak [perl #75176].
3432
3433=back
3434
3435In addition, various other bugs related to typeglobs and stashes have been
3436fixed:
5076a392 3437
e8e35311 3438=over
5076a392
FC
3439
3440=item *
3441
e8e35311 3442Some work has been done on the internal pointers that link between symbol
e262cb24 3443tables (stashes), typeglobs and subroutines. This has the effect that
e8e35311
FC
3444various edge cases related to deleting stashes or stash entries (e.g.
3445<%FOO:: = ()>), and complex typeglob or code reference aliasing, will no
3446longer crash the interpreter.
5076a392
FC
3447
3448=item *
3449
e262cb24
FC
3450Assigning a reference to a glob copy now assigns to a glob slot instead of
3451overwriting the glob with a scalar [perl #1804] [perl #77508].
5076a392
FC
3452
3453=item *
3454
e8e35311
FC
3455A bug when replacing the glob of a loop variable within the loop has been fixed
3456[perl #21469]. This
3457means the following code will no longer crash:
5076a392 3458
e8e35311
FC
3459 for $x (...) {
3460 *x = *y;
3461 }
5076a392
FC
3462
3463=item *
3464
3465Assigning a glob to a PVLV used to convert it to a plain string. Now it
3466works correctly, and a PVLV can hold a glob. This would happen when a
3467nonexistent hash or array element was passed to a subroutine:
3468
3469 sub { $_[0] = *foo }->($hash{key});
3470 # $_[0] would have been the string "*main::foo"
3471
3472It also happened when a glob was assigned to, or returned from, an element
3473of a tied array or hash [perl #36051].
3474
3475=item *
44691e6f 3476
e8e35311 3477When trying to report C<Use of uninitialized value $Foo::BAR>, crashes could
e262cb24
FC
3478occur if the glob holding the global variable in question had been detached
3479from its original stash by, for example, C<delete $::{'Foo::'}>. This has
3480been fixed by disabling the reporting of variable names in those
e8e35311 3481cases.
44691e6f
AB
3482
3483=item *
3484
e8e35311
FC
3485During the restoration of a localised typeglob on scope exit, any
3486destructors called as a result would be able to see the typeglob in an
3487inconsistent state, containing freed entries, which could result in a
3488crash. This would affect code like this:
3489
3490 local *@;
3491 eval { die bless [] }; # puts an object in $@
3492 sub DESTROY {
3493 local $@; # boom
3494 }
3495
3496Now the glob entries are cleared before any destructors are called. This
3497also means that destructors can vivify entries in the glob. So perl tries
3498again and, if the entries are re-created too many times, dies with a
3499'panic: gp_free...' error message.
3500
3501=back
3502
3503=head2 Unicode
3504
3505=over
44691e6f 3506
5076a392 3507=item *
44691e6f 3508
e8e35311
FC
3509What has become known as the "Unicode Bug" is mostly resolved in this release.
3510Under C<use feature 'unicode_strings'>, the internal storage format of a
3511string no longer affects the external semantics. There are two known
3512exceptions. User-defined case changing functions, which are planned to
3513be deprecated in 5.14, require utf8-encoded strings to function; and the
3514character C<LATIN SMALL LETTER SHARP S> in regular expression
3515case-insensitive matching has a somewhat different set of bugs depending
3516on the internal storage format. Case-insensitive matching of all
3517characters that have multi-character matches, as this one does, is
3518problematical in Perl [perl #58182].
911a3729 3519
5076a392 3520=item *
c8c13991 3521
e8e35311
FC
3522The handling of Unicode non-characters has changed.
3523Previously they were mostly considered illegal, except that only one of
3524the 66 of them was known about in places. The Unicode standard
3525considers them legal, but forbids the "open interchange" of them.
3526This is part of the change to allow the internal use of any code point
3527(see L</Core Enhancements>). Together, these changes resolve
9a5a48b7
FC
3528[perl #38722], [perl #51918], [perl #51936], [perl #63446].
3529
3530=item *
3531
3532Naming a deprecated character in \N{...} no longer leaks memory.
3533
3534=item *
3535
cdc10f43
FC
3536We fixed a bug that could cause \N{} constructs followed by a single . to
3537be parsed incorrectly [perl #74978] (5.12.1).
3538
3539=item *
3540
9a5a48b7
FC
3541C<chop> now correctly handles characters above "\x{7fffffff}"
3542[perl #73246].
3543
3544=item *
3545
3546Passing to C<index> an offset beyond the end of the string when the string
3547is encoded internally in UTF8 no longer causes panics [perl #75898].
3548
3549=item *
3550
3551C<warn()> and C<die()> now respect utf8-encoded scalars [perl #45549].
c8c13991 3552
5076a392
FC
3553=item *
3554
9a5a48b7 3555Sometimes the UTF8 length cache would not be reset on a value
e8e35311 3556returned by substr, causing C<length(substr($uni_string,...))> to give
9a5a48b7
FC
3557wrong answers. With C<${^UTF8CACHE}> set to -1, it would produce a 'panic'
3558error message, too [perl #77692].
e8e35311
FC
3559
3560=back
3561
e9784f55 3562=head2 Ties, Overloading and Other Magic
e8e35311
FC
3563
3564=over
35cdccfc