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Correct the B::Concise 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
4a75fbf5 1245C<B::Concise> has been upgraded from version 0.78 to 0.83.
5076a392
FC
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
6bb8c1e3
FR
1255C<B::Debug> has been upgraded from version 1.12 to 1.16.
1256
1257=item *
1258
c67a4e29 1259C<B::Deparse> has been upgraded from version 0.96 to 1.03.
5076a392 1260
1984204c 1261The deparsing of a nextstate op has changed when it has both a
5076a392
FC
1262change of package (relative to the previous nextstate), or a change of
1263C<%^H> or other state, and a label. Previously the label was emitted
cdc10f43 1264first, but now the label is emitted last (5.12.1).
5076a392 1265
5a553547
FC
1266The C<no 5.13.2> or similar form is now correctly handled by B::Deparse
1267(5.12.3).
5076a392
FC
1268
1269B::Deparse now properly handles the code that applies a conditional
1270pattern match against implicit C<$_> as it was fixed in [perl #20444].
1271
1984204c
FC
1272Deparsing of C<our> followed by a variable with funny characters
1273(as permitted under the C<utf8> pragma) has also been fixed [perl #33752].
5076a392
FC
1274
1275=item *
1276
d97c5d3b
FR
1277C<B::Lint> has been upgraded from version 1.11_01 to 1.13.
1278
1279=item *
1280
5aef2c44
FR
1281C<base> has been upgraded from version 2.15 to 2.16.
1282
1283=item *
1284
e539ae69
FR
1285C<bignum> has been upgraded from version 0.23 to 0.26.
1286
1287=item *
1288
c74c1fa8 1289C<Carp> has been upgraded from version 1.15 to 1.20.
5076a392
FC
1290
1291L<Carp> now detects incomplete L<caller()|perlfunc/"caller EXPR"> overrides and
d430b8e7
FC
1292avoids using bogus C<@DB::args>. To provide backtraces,
1293Carp relies on particular behaviour of the C<caller>
1294built-in. Carp now detects if other code has
5076a392 1295overridden this with an incomplete implementation, and modifies its backtrace
d430b8e7
FC
1296accordingly. Previously incomplete overrides would cause incorrect values
1297in backtraces (best case), or obscure fatal errors (worst case).
5076a392
FC
1298
1299This fixes certain cases of C<Bizarre copy of ARRAY> caused by modules
d430b8e7 1300overriding C<caller()> incorrectly (5.12.2).
5076a392 1301
1984204c 1302It now also avoids using regular expressions that cause perl to
5076a392
FC
1303load its Unicode tables, in order to avoid the 'BEGIN not safe after
1304errors' error that will ensue if there has been a syntax error
1305[perl #82854].
1306
1307=item *
1308
9eb7ad55 1309C<CGI> has been upgraded from version 3.48 to 3.52.
5076a392
FC
1310
1311This provides the following security fixes: the MIME boundary in
1984204c
FC
1312multipart_init is now random and the handling of
1313newlines embedded in header values has been improved.
5076a392
FC
1314
1315=item *
1316
5076a392
FC
1317C<Compress::Raw::Bzip2> has been upgraded from version 2.024 to 2.033.
1318
1984204c 1319It has been updated to use bzip2 1.0.6.
5076a392
FC
1320
1321=item *
1322
51090521
FR
1323C<Compress::Raw::Zlib> has been upgraded from version 2.024 to 2.033.
1324
1325=item *
1326
f75b7efc 1327C<CPAN> has been upgraded from version 1.94_56 to 1.9600.
1984204c
FC
1328
1329Major highlights:
5076a392
FC
1330
1331=over 4
1332
1984204c 1333=item * much less configuration dialog hassle
5076a392 1334
1984204c 1335=item * support for META/MYMETA.json
5076a392 1336
1984204c 1337=item * support for local::lib
5076a392 1338
1984204c 1339=item * support for HTTP::Tiny to reduce the dependency on ftp sites
5076a392 1340
1984204c 1341=item * automatic mirror selection
5076a392 1342
1984204c 1343=item * iron out all known bugs in configure_requires
5076a392 1344
1984204c
FC
1345=item * support for distributions compressed with bzip2
1346
1347=item * allow Foo/Bar.pm on the commandline to mean Foo::Bar
1348
1349=back
5076a392
FC
1350
1351=item *
1352
d430b8e7
FC
1353C<CPANPLUS> has been upgraded from version 0.90 to 0.9103.
1354
1355A change to F<cpanp-run-perl>
1356resolves L<RT #55964|http://rt.cpan.org/Public/Bug/Display.html?id=55964>
1357and L<RT #57106|http://rt.cpan.org/Public/Bug/Display.html?id=57106>, both
1358of which related to failures to install distributions that use
1359C<Module::Install::DSL> (5.12.2).
5076a392 1360
1984204c
FC
1361A dependency on Config was not recognised as a
1362core module dependency. This has been fixed.
5076a392 1363
1984204c 1364CPANPLUS now includes support for META.json and MYMETA.json.
5076a392
FC
1365
1366=item *
1367
4467e8f7
FR
1368C<CPANPLUS::Dist::Build> has been upgraded from version 0.46 to 0.54.
1369
1370=item *
1371
5076a392
FC
1372C<Data::Dumper> has been upgraded from version 2.125 to 2.130_02.
1373
4ed2cea4
FC
1374The indentation used to be off when C<$Data::Dumper::Terse> was set. This
1375has been fixed [perl #73604].
1376
1984204c
FC
1377This upgrade also fixes a crash when using custom sort functions that might
1378cause the stack to change [perl #74170].
5076a392
FC
1379
1380C<Dumpxs> no longer crashes with globs returned by C<*$io_ref>
1381[perl #72332].
1382
1383=item *
1384
549d34f5
FR
1385C<DB_File> has been upgraded from version 1.820 to 1.821.
1386
1387=item *
1388
5076a392
FC
1389C<Devel::DProf> has been upgraded from version 20080331.00 to 20110228.00.
1390
1391Merely loading C<Devel::DProf> now no longer triggers profiling to start.
1392C<use Devel::DProf> and C<perl -d:DProf ...> still behave as before and start
1393the profiler.
1394
1395NOTE: C<Devel::DProf> is deprecated and will be removed from a future
1984204c 1396version of Perl. We strongly recommend that you install and use
5076a392
FC
1397L<Devel::NYTProf> instead, as it offers significantly improved
1398profiling and reporting.
1399
1400=item *
1401
66899ca3
FR
1402C<Devel::SelfStubber> has been upgraded from version 1.03 to 1.05.
1403
1404=item *
1405
5076a392
FC
1406C<diagnostics> has been upgraded from version 1.19 to 1.22.
1407
1408It now renders pod links slightly better, and has been taught to find
1409descriptions for messages that share their descriptions with other
1410messages.
1411
1412=item *
1413
1414C<Digest::MD5> has been upgraded from version 2.39 to 2.51.
1415
1416It is now safe to use this module in combination with threads.
1417
1418=item *
1419
1420C<Digest::SHA> has been upgraded from version 5.47 to 5.61.
1421
1422C<shasum> now more closely mimics C<sha1sum>/C<md5sum>.
1423
1424C<Addfile> accepts all POSIX filenames.
1425
1984204c
FC
1426New SHA-512/224 and SHA-512/256 transforms (ref. NIST Draft FIPS 180-4
1427[February 2011])
5076a392
FC
1428
1429=item *
1430
e53cbaa3
FR
1431C<Dumpvalue> has been upgraded from version 1.13 to 1.16.
1432
1433=item *
1434
31e8b85a 1435C<DynaLoader> has been upgraded from version 1.10 to 1.13.
5076a392
FC
1436
1437It fixes a buffer overflow when passed a very long file name.
1438
1439It no longer inherits from AutoLoader; hence it no longer
1440produces weird error messages for unsuccessful method calls on classes that
1441inherit from DynaLoader [perl #84358].
1442
1443=item *
1444
1445C<Encode> has been upgraded from version 2.39 to 2.42.
1446
1447Now, all 66 Unicode non-characters are treated the same way U+FFFF has
1984204c
FC
1448always been treated; in cases when it was disallowed, all 66 are
1449disallowed; in those cases where it warned, all 66 warn.
5076a392
FC
1450
1451=item *
1452
68f90ac3
FR
1453C<Env> has been upgraded from version 1.01 to 1.02.
1454
1455=item *
1456
5076a392
FC
1457C<Errno> has been upgraded from version 1.11 to 1.13.
1458
1459The implementation of C<Errno> has been refactored to use about 55% less memory.
5076a392
FC
1460
1461On some platforms with unusual header files, like Win32/gcc using mingw64
1462headers, some constants which weren't actually error numbers have been exposed
1463by C<Errno>. This has been fixed [perl #77416].
1464
1465=item *
1466
1467C<Exporter> has been upgraded from version 5.64_01 to 5.64_03.
1468
1469Exporter no longer overrides C<$SIG{__WARN__}> [perl #74472]
1470
1471=item *
1472
25fe7f8f
FR
1473C<ExtUtils::CBuilder> has been upgraded from version 0.27 to 0.280202.
1474
1475=item *
1476
2292e71e
FR
1477C<ExtUtils::Command> has been upgraded from version 1.16 to 1.17.
1478
1479=item *
1480
5076a392
FC
1481C<ExtUtils::Constant> has been upgraded from 0.22 to 0.23.
1482
1483The C<AUTOLOAD> helper code generated by C<ExtUtils::Constant::ProxySubs>
1484can now C<croak> for missing constants, or generate a complete C<AUTOLOAD>
1984204c
FC
1485subroutine in XS, allowing simplification of many modules that use it
1486(C<Fcntl>, C<File::Glob>, C<GDBM_File>, C<I18N::Langinfo>, C<POSIX>,
1487C<Socket>).
5076a392
FC
1488
1489C<ExtUtils::Constant::ProxySubs> can now optionally push the names of all
1984204c 1490constants onto the package's C<@EXPORT_OK>.
5076a392
FC
1491
1492=item *
1493
588c5853
FR
1494C<ExtUtils::Install> has been upgraded from version 1.55 to 1.56.
1495
1496=item *
1497
5418ffb3
FR
1498C<ExtUtils::MakeMaker> has been upgraded from version 6.56 to 6.57_05.
1499
1500=item *
1501
f40ab45f
FR
1502C<ExtUtils::Manifest> has been upgraded from version 1.57 to 1.58.
1503
1504=item *
1505
b7064dd7
FR
1506C<ExtUtils::ParseXS> has been upgraded from version 2.21 to 2.2209.
1507
1508=item *
1509
05102622
FR
1510C<File::CheckTree> has been upgraded from version 4.4 to 4.41.
1511
1512=item *
1513
e12786fa 1514C<File::DosGlob> has been upgraded from version 1.01 to 1.04.
5076a392
FC
1515
1516It allows patterns containing literal parentheses (they no longer need to
1984204c
FC
1517be escaped). On Windows, it no longer
1518adds an extra F<./> to the file names
5076a392
FC
1519returned when the pattern is a relative glob with a drive specification,
1520like F<c:*.pl> [perl #71712].
1521
1522=item *
1523
1524C<File::Fetch> has been upgraded from version 0.24 to 0.32.
1525
1526C<HTTP::Lite> is now supported for 'http' scheme.
1527
1528The C<fetch> utility is supported on FreeBSD, NetBSD and
1529Dragonfly BSD for the C<http> and C<ftp> schemes.
1530
1531=item *
1532
23f2cbb1 1533C<File::Find> has been upgraded from version 1.15 to 1.19.
5076a392 1534
1984204c 1535It improves handling of backslashes on Windows, so that paths like
5076a392
FC
1536F<c:\dir\/file> are no longer generated [perl #71710].
1537
1538=item *
1539
d430b8e7
FC
1540C<File::Spec> has been upgraded from version 3.31 to 3.33.
1541
1542Several portability fixes were made in C<File::Spec::VMS>: a colon is now
1543recognized as a delimiter in native filespecs; caret-escaped delimiters are
1544recognized for better handling of extended filespecs; C<catpath()> returns
1545an empty directory rather than the current directory if the input directory
1546name is empty; C<abs2rel()> properly handles Unix-style input (5.12.2).
1547
1548=item *
1549
46ba0657 1550C<File::stat> has been upgraded from 1.02 to 1.05.
5076a392
FC
1551
1552The C<-x> and C<-X> file test operators now work correctly under the root
1553user.
1554
1555=item *
1556
b7edcc3c
FR
1557C<Filter::Simple> has been upgraded from version 0.84 to 0.86.
1558
1559=item *
1560
dc6857fd 1561C<GDBM_File> has been upgraded from 1.10 to 1.14.
5076a392
FC
1562
1563This fixes a memory leak when DBM filters are used.
1564
1565=item *
1566
6e107b45 1567C<Hash::Util> has been upgraded from 0.07 to 0.11.
5076a392 1568
1984204c
FC
1569Hash::Util no longer emits spurious "uninitialized" warnings when
1570recursively locking hashes that have undefined values [perl #74280].
5076a392
FC
1571
1572=item *
1573
eec33fe6
FR
1574C<I18N::Collate> has been upgraded from version 1.01 to 1.02.
1575
1576=item *
1577
ad5f8f47 1578C<I18N::Langinfo> has been upgraded from version 0.03 to 0.08.
5076a392
FC
1579
1580C<langinfo()> now defaults to using C<$_> if there is no argument given, just
5334145a 1581as the documentation has always claimed.
5076a392
FC
1582
1583=item *
1584
c41635f7
FR
1585C<I18N::LangTags> has been upgraded from version 0.35 to 0.35_01.
1586
1587=item *
1588
98a6a4ff
FR
1589C<if> has been upgraded from version 0.05 to 0.0601.
1590
1591=item *
1592
f6ff7fb6
FR
1593C<IO> has been upgraded from version 1.25_02 to 1.25_04.
1594
1595=item *
1596
d13528c5 1597C<IO::Select> has been upgraded from version 1.17 to 1.20.
5076a392
FC
1598
1599It now allows IO::Handle objects (and objects in derived classes) to be
1600removed from an IO::Select set even if the underlying file descriptor is
1601closed or invalid.
1602
1603=item *
1604
d07561d3 1605C<IPC::Cmd> has been upgraded from version 0.54 to 0.70.
5076a392 1606
1984204c
FC
1607Resolves an issue with splitting Win32 command lines. An argument
1608consisting of the single character "0" used to be omitted (CPAN RT #62961).
5076a392
FC
1609
1610=item *
1611
3f16e4eb 1612C<IPC::Open3> has been upgraded from 1.05 to 1.09.
5076a392 1613
4ed2cea4
FC
1614C<open3> now produces an error if the C<exec> call fails, allowing this
1615condition to be distinguished from a child process that exited with a
1616non-zero status [perl #72016].
1617
5076a392
FC
1618The internal C<xclose> routine now knows how to handle file descriptors, as
1619documented, so duplicating STDIN in a child process using its file
1620descriptor now works [perl #76474].
1621
1622=item *
1623
c8b41807
FR
1624C<IPC::SysV> has been upgraded from version 2.01 to 2.03.
1625
1626=item *
1627
ef79f038
FR
1628C<lib> has been upgraded from version 0.62 to 0.63.
1629
1630=item *
1631
5b1884f4 1632C<Locale::Maketext> has been upgraded from version 1.14 to 1.19.
5076a392 1633
1984204c 1634Locale::Maketext now supports external caches.
5076a392 1635
1984204c
FC
1636This upgrade also fixes an infinite loop in
1637C<Locale::Maketext::Guts::_compile()> when
5076a392
FC
1638working with tainted values (CPAN RT #40727).
1639
1984204c 1640C<< ->maketext >> calls will now back up and restore C<$@> so that error
5076a392
FC
1641messages are not suppressed (CPAN RT #34182).
1642
1643=item *
1644
3811bd2b
FR
1645C<Log::Message> has been upgraded from version 0.02 to 0.04.
1646
1647=item *
1648
8eb65377
FR
1649C<Log::Message::Simple> has been upgraded from version 0.06 to 0.08.
1650
1651=item *
1652
5076a392
FC
1653C<Math::BigInt> has been upgraded from version 1.89_01 to 1.994.
1654
1655This fixes, among other things, incorrect results when computing binomial
1656coefficients [perl #77640].
1657
1984204c 1658It also prevents C<sqrt($int)> from crashing under C<use bigrat;>
5076a392
FC
1659[perl #73534].
1660
1661=item *
1662
846c1cec
FR
1663C<Math::BigInt::FastCalc> has been upgraded from version 0.19 to 0.28.
1664
1665=item *
1666
fce4aef3
FR
1667C<Math::BigRat> has been upgraded from version 0.24 to 0.26_02.
1668
1669=item *
1670
12e26027
FR
1671C<Memoize> has been upgraded from version 1.01_03 to 1.02.
1672
1673=item *
1674
5076a392
FC
1675C<MIME::Base64> has been upgraded from 3.08 to 3.13.
1676
1677Includes new functions to calculate the length of encoded and decoded
1678base64 strings.
1679
1680Now provides C<encode_base64url> and C<decode_base64url> functions to process
1681the base64 scheme for "URL applications".
1682
1683=item *
1684
1685C<Module::Build> has been upgraded from version 0.3603 to 0.3800.
1686
1687A notable change is the deprecation of several modules.
1688Module::Build::Version has been deprecated and Module::Build now relies
1689directly upon L<version>. Module::Build::ModuleInfo has been deprecated in
1690favor of a standalone copy of it called L<Module::Metadata>.
1691Module::Build::YAML has been deprecated in favor of L<CPAN::Meta::YAML>.
1692
1693Module::Build now also generates META.json and MYMETA.json files
1694in accordance with version 2 of the CPAN distribution metadata specification,
1695L<CPAN::Meta::Spec>. The older format META.yml and MYMETA.yml files are
1696still generated, as well.
1697
1698=item *
1699
7259fe26 1700C<Module::CoreList> has been upgraded from version 2.29 to 2.47.
5076a392
FC
1701
1702Besides listing the updated core modules of this release, it also stops listing
1984204c 1703the C<Filespec> module. That module never existed in core. The scripts
5076a392 1704generating C<Module::CoreList> confused it with C<VMS::Filespec>, which actually
1984204c 1705is a core module as of perl 5.8.7.
5076a392
FC
1706
1707=item *
1708
193af05b
FR
1709C<Module::Load> has been upgraded from version 0.16 to 0.18.
1710
1711=item *
1712
5b3a054f
FR
1713C<Module::Load::Conditional> has been upgraded from version 0.34 to 0.44.
1714
1715=item *
1716
4f978a3b
FR
1717C<NDBM_File> has been upgraded from version 1.08 to 1.11.
1718
1719This fixes a memory leak when DBM filters are used.
1720
1721=item *
1722
d0aa5c91
FR
1723C<Net::Ping> has been upgraded from version 2.36 to 2.38.
1724
1725=item *
1726
d44b8a8c
FR
1727C<NEXT> has been upgraded from version 0.64 to 0.65.
1728
1729=item *
1730
678d4fd4
FR
1731C<Object::Accessor> has been upgraded from version 0.36 to 0.38.
1732
1733=item *
1734
34188656 1735C<ODBM_File> have been upgraded from version 1.07 to 1.10.
5076a392
FC
1736
1737This fixes a memory leak when DBM filters are used.
1738
1739=item *
1740
77be713d 1741C<overload> has been upgraded from 1.10 to 1.12.
5076a392
FC
1742
1743C<overload::Method> can now handle subroutines that are themselves blessed
1744into overloaded classes [perl #71998].
1745
5076a392
FC
1746The documentation has greatly improved. See L</Documentation> below.
1747
1748=item *
1749
f84c796e
FR
1750C<Params::Check> has been upgraded from version 0.26 to 0.28.
1751
1752=item *
1753
550ee92b
FR
1754C<parent> has been upgraded from version 0.223 to 0.225.
1755
1756=item *
1757
5076a392
FC
1758C<Parse::CPAN::Meta> has been upgraded from version 1.40 to 1.4401.
1759
1984204c 1760The latest Parse::CPAN::Meta can now read YAML and JSON files using
5076a392
FC
1761L<CPAN::Meta::YAML> and L<JSON::PP>, which are now part of the Perl core.
1762
1763=item *
1764
5076a392
FC
1765C<PerlIO::scalar> has been upgraded from 0.07 to 0.11.
1766
1767A C<read> after a C<seek> beyond the end of the string no longer thinks it
1768has data to read [perl #78716].
1769
1770=item *
1771
be3c8498
FR
1772C<Pod::LaTeX> has been upgraded from version 0.58 to 0.59.
1773
1774=item *
1775
fd8a2e89
FR
1776C<Pod::Perldoc> has been upgraded from version 3.15_02 to 3.15_03.
1777
1778=item *
1779
5bcb6583
FR
1780C<Pod::Simple> has been upgraded from version 3.13 to 3.16.
1781
1782=item *
1783
abb8c779 1784C<POSIX> has been upgraded from 1.19 to 1.24.
5076a392
FC
1785
1786It now includes constants for POSIX signal constants.
1787
1788=item *
1789
1984204c 1790C<re> has been upgraded from version 0.11 to 0.17.
5076a392
FC
1791
1792New C<use re "/flags"> pragma
1793
5076a392 1794The C<regmust> function used to crash when called on a regular expression
1984204c 1795belonging to a pluggable engine. Now it croaks instead.
5076a392
FC
1796
1797C<regmust> no longer leaks memory.
1798
1799=item *
1800
1801C<Safe> has been upgraded from version 2.25 to 2.29.
1802
cdc10f43
FC
1803Coderefs returned by C<reval()> and C<rdo()> are now wrapped via
1804C<wrap_code_refs> (5.12.1).
1805
5076a392
FC
1806This fixes a possible infinite loop when looking for coderefs.
1807
cdc10f43 1808It adds several version::vxs::* routines to the default share.
5076a392
FC
1809
1810=item *
1811
5076a392
FC
1812C<SelfLoader> has been upgraded from 1.17 to 1.18.
1813
1814It now works in taint mode [perl #72062].
1815
1816=item *
1817
1818C<sigtrap> has been upgraded from version 1.04 to 1.05.
1819
1820It no longer tries to modify read-only arguments when generating a
1821backtrace [perl #72340].
1822
1823=item *
1824
1984204c 1825C<Socket> has been upgraded from version 1.87 to 1.94.
5076a392 1826
1984204c 1827See L</IPv6 support>, above.
5076a392
FC
1828
1829=item *
1830
1831C<Storable> has been upgraded from version 2.22 to 2.27.
1832
1833Includes performance improvement for overloaded classes.
1834
5076a392 1835This adds support for serialising code references that contain UTF-8 strings
1984204c
FC
1836correctly. The Storable minor version
1837number changed as a result, meaning that
5076a392
FC
1838Storable users who set C<$Storable::accept_future_minor> to a C<FALSE> value
1839will see errors (see L<Storable/FORWARD COMPATIBILITY> for more details).
1840
1841Freezing no longer gets confused if the Perl stack gets reallocated
1842during freezing [perl #80074].
1843
1844=item *
1845
90c6e78f
FR
1846C<Term::ANSIColor> has been upgraded from version 2.02 to 3.00.
1847
1848=item *
1849
d9f2f059
FR
1850C<Term::UI> has been upgraded from version 0.20 to 0.26.
1851
1852=item *
1853
80ebb519
FR
1854C<Test::Harness> has been upgraded from version 3.17 to 3.23.
1855
1856=item *
1857
5076a392
FC
1858C<Test::Simple> has been upgraded from version 0.94 to 0.98.
1859
1860Among many other things, subtests without a C<plan> or C<no_plan> now have an
1861implicit C<done_testing()> added to them.
1862
1863=item *
1864
5076a392
FC
1865C<Thread::Semaphore> has been upgraded from version 2.09 to 2.12.
1866
1984204c
FC
1867It provides two new methods that give more control over the decrementing of
1868semaphores: C<down_nb> and C<down_force>.
5076a392
FC
1869
1870=item *
1871
f0d895e1
FR
1872C<Thread::Queue> has been upgraded from version 2.11 to 2.12.
1873
1874=item *
1875
1a6b954e
FR
1876C<threads> has been upgraded from version 1.75 to 1.83.
1877
1878=item *
1879
55816daa
FR
1880C<threads::shared> has been upgraded from version 1.32 to 1.36.
1881
1882=item *
1883
5076a392
FC
1884C<Tie::Hash> has been upgraded from version 1.03 to 1.04.
1885
1886Calling C<< Tie::Hash-E<gt>TIEHASH() >> used to loop forever. Now it C<croak>s.
1887
1888=item *
1889
ed68b07e
FR
1890C<Tie::RefHash> has been upgraded from version 1.38 to 1.39.
1891
1892=item *
1893
bb3c221a
FR
1894C<Time::HiRes> has been upgraded from version 1.9719 to 1.9721_01.
1895
1896=item *
1897
97fa568b
FR
1898C<Time::Local> has been upgraded from version 1.1901_01 to 1.2000.
1899
1900=item *
1901
a83cb732
FR
1902C<Time::Piece> has been upgraded from version 1.15_01 to 1.20_01.
1903
1904=item *
1905
5076a392
FC
1906C<Unicode::Collate> has been upgraded from version 0.52_01 to 0.73.
1907
1984204c 1908Unicode::Collate has been updated to use Unicode 6.0.0.
5076a392 1909
1984204c
FC
1910Unicode::Collate::Locale now supports a plethora of new locales: ar, be,
1911bg, de__phonebook, hu, hy, kk, mk, nso, om, tn, vi, hr, ig, ja, ko, ru, sq,
1912se, sr, to, uk, zh, zh__big5han, zh__gb2312han, zh__pinyin and zh__stroke.
5076a392
FC
1913
1914The following modules have been added:
1915
1916C<Unicode::Collate::CJK::Big5> for C<zh__big5han> which makes
1917tailoring of CJK Unified Ideographs in the order of CLDR's big5han ordering.
1918
1919C<Unicode::Collate::CJK::GB2312> for C<zh__gb2312han> which makes
1920tailoring of CJK Unified Ideographs in the order of CLDR's gb2312han ordering.
1921
1922C<Unicode::Collate::CJK::JISX0208> which makes tailoring of 6355 kanji
1923(CJK Unified Ideographs) in the JIS X 0208 order.
1924
1925C<Unicode::Collate::CJK::Korean> which makes tailoring of CJK Unified Ideographs
1926in the order of CLDR's Korean ordering.
1927
1928C<Unicode::Collate::CJK::Pinyin> for C<zh__pinyin> which makes
1929tailoring of CJK Unified Ideographs in the order of CLDR's pinyin ordering.
1930
1931C<Unicode::Collate::CJK::Stroke> for C<zh__stroke> which makes
1932tailoring of CJK Unified Ideographs in the order of CLDR's stroke ordering.
1933
5076a392
FC
1934This also sees the switch from using the pure-perl version of this
1935module to the XS version.
1936
1937=item *
1938
ec52b54b
FR
1939C<Unicode::Normalize> has been upgraded from version 1.03 to 1.10.
1940
1941=item *
1942
5076a392
FC
1943C<Unicode::UCD> has been upgraded from version 0.27 to 0.32.
1944
1984204c
FC
1945A new function, C<Unicode::UCD::num()>, has been added. This function
1946returns the numeric value of the string passed it or C<undef> if the string
1947in its entirety has no "safe" numeric value. (For more detail, and for the
1948definition of "safe", see L<Unicode::UCD/num>.)
5076a392 1949
1984204c 1950This upgrade also includes a number of bug fixes:
5076a392
FC
1951
1952=over 4
1953
1954=item charinfo()
1955
1956=over 4
1957
1958=item *
1959
1960It is now updated to Unicode Version 6 with Corrigendum #8, except,
1961as with Perl 5.14, the code point at U+1F514 has no name.
1962
1963=item *
1964
1965The Hangul syllable code points have the correct names, and their
1966decompositions are always output without requiring L<Lingua::KO::Hangul::Util>
1967to be installed.
1968
1969=item *
1970
54c7bb16
FC
1971The CJK (Chinese-Japanese-Korean) code points U+2A700 to U+2B734
1972and U+2B740 to U+2B81D are now properly handled.
5076a392
FC
1973
1974=item *
1975
1976The numeric values are now output for those CJK code points that have them.
1977
1978=item *
1979
1980The names that are output for code points with multiple aliases are now the
1981corrected ones.
1982
1983=back
1984
1985=item charscript()
1986
1987This now correctly returns "Unknown" instead of C<undef> for the script
1988of a code point that hasn't been assigned another one.
1989
1990=item charblock()
1991
1992This now correctly returns "No_Block" instead of C<undef> for the block
1993of a code point that hasn't been assigned to another one.
1994
1995=back
1996
5076a392
FC
1997=item *
1998
1999C<version> has been upgraded from 0.82 to 0.88.
2000
1984204c 2001Due to a bug, now fixed, the C<is_strict> and C<is_lax> functions did not
cdc10f43 2002work when exported (5.12.1).
5076a392
FC
2003
2004=item *
2005
3e625598 2006C<warnings> has been upgraded from version 1.09 to 1.12.
5076a392
FC
2007
2008Calling C<use warnings> without arguments is now significantly more efficient.
2009
4f978a3b
FR
2010=item *
2011
2012C<warnings::register> have been upgraded from version 1.01 to 1.02.
2013
5076a392
FC
2014It is now possible to register warning categories other than the names of
2015packages using C<warnings::register>. See L<perllexwarn> for more information.
2016
2017=item *
2018
62e270c2
FR
2019C<XSLoader> has been upgraded from version 0.10 to 0.13.
2020
2021=item *
2022
5076a392
FC
2023C<VMS::DCLsym> has been upgraded from version 1.03 to 1.05.
2024
2025Two bugs have been fixed [perl #84086]:
2026
2027The symbol table name was lost when tying a hash, due to a thinko in
2028C<TIEHASH>. The result was that all tied hashes interacted with the
2029local symbol table.
2030
2031Unless a symbol table name had been explicitly specified in the call
2032to the constructor, querying the special key ':LOCAL' failed to
2033identify objects connected to the local symbol table.
2034
2035=item *
2036
2037C<Win32> has been upgraded from version 0.39 to 0.44.
2038
1984204c
FC
2039This release has several new functions: C<Win32::GetSystemMetrics>,
2040C<Win32::GetProductInfo>, C<Win32::GetOSDisplayName>.
5076a392 2041
1984204c
FC
2042The names returned by C<Win32::GetOSName> and C<Win32::GetOSDisplayName>
2043have been corrected.
5076a392 2044
5076a392
FC
2045=back
2046
5076a392
FC
2047=head2 Removed Modules and Pragmata
2048
2049The following modules have been removed from the core distribution, and if
2050needed should be installed from CPAN instead.
2051
2052=over
2053
4f978a3b
FR
2054=item *
2055
2056C<Class::ISA> has been removed from the Perl core. Prior version was 0.36.
5076a392 2057
4f978a3b
FR
2058=item *
2059
2060C<Pod::Plainer> has been removed from the Perl core. Prior version was 1.02.
2061
2062=item *
5076a392 2063
4f978a3b 2064C<Switch> has been removed from the Perl core. Prior version was 2.16.
5076a392
FC
2065
2066=back
2067
2068The removal of C<Shell> has been deferred until after 5.14, as the
2069implementation of C<Shell> shipped with 5.12.0 did not correctly issue the
2070warning that it was to be removed from core.
2071
2072=head1 Documentation
2073
5076a392
FC
2074=head2 New Documentation
2075
41e29def 2076=head3 L<perlgpl>
5076a392
FC
2077
2078L<perlgpl> has been updated to contain GPL version 1, as is included in the
cdc10f43 2079F<README> distributed with perl (5.12.1).
5076a392 2080
41e29def 2081=head3 Perl 5.12.x delta files
5076a392 2082
41e29def
FC
2083The perldelta files for Perl 5.12.1 to 5.12.3 have been added from the
2084maintenance branch: L<perl5121delta>, L<perl5122delta>, L<perl5123delta>.
5076a392
FC
2085
2086=head3 L<perlpodstyle>
2087
2088New style guide for POD documentation,
2089split mostly from the NOTES section of the pod2man man page.
2090
41e29def
FC
2091=head3 L<perlsource>, L<perlinterp>, L<perlhacktut>, and L<perlhacktips>
2092
2093See L</L<perlhack> and perlrepository revamp>, below.
5076a392
FC
2094
2095=head2 Changes to Existing Documentation
2096
41e29def 2097=head3 L<perlmodlib> is now complete
4ed2cea4
FC
2098
2099The perlmodlib page that came with Perl 5.12.0 was missing a lot of
2100modules, due to a bug in the script that generates the list. This has been
cdc10f43 2101fixed [perl #74332] (5.12.1).
4ed2cea4 2102
41e29def 2103=head3 Replace wrong tr/// table in L<perlebcdic>
5076a392 2104
41e29def 2105L<perlebcdic> contains a helpful table to use in tr/// to convert
5076a392
FC
2106between EBCDIC and Latin1/ASCII. Unfortunately, the table was the
2107inverse of the one it describes, though the code that used the table
2108worked correctly for the specific example given.
2109
2110The table has been changed to its inverse, and the sample code changed
2111to correspond, as this is easier for the person trying to follow the
2112instructions since deriving the old table is somewhat more complicated.
2113
2114The table has also been changed to hex from octal, as that is more the norm
2115these days, and the recipes in the pod altered to print out leading
41e29def 2116zeros to make all the values the same length.
5076a392 2117
41e29def 2118=head3 Tricks for user-defined casing
5076a392 2119
41e29def
FC
2120L<perlunicode> now contains an explanation of how to override, mangle
2121and otherwise tweak the way perl handles upper-, lower- and other-case
2122conversions on Unicode data, and how to provide scoped changes to alter
2123one's own code's behaviour without stomping on anybody else.
5076a392
FC
2124
2125=head3 INSTALL explicitly states the requirement for C89
2126
d430b8e7
FC
2127This was already true but it's now Officially Stated For The Record
2128(5.12.2).
5076a392 2129
41e29def 2130=head3 Explanation of C<\xI<HH>> and C<\oI<OOO>> escapes
5076a392 2131
41e29def
FC
2132L<perlop> has been updated with more detailed explanation of these two
2133character escapes.
5076a392 2134
41e29def 2135=head3 C<-0I<NNN>> switch
5076a392 2136
41e29def 2137In L<perlrun>, the behavior of the C<-0NNN> switch for C<-0400> or higher
d430b8e7 2138has been clarified (5.12.2).
5076a392 2139
cdc10f43
FC
2140=head3 Maintenance policy
2141
2142L<perlpolicy> now contains the policy on what patches are acceptable for
2143maintenance branches (5.12.1).
2144
41e29def 2145=head3 Deprecation policy
5076a392 2146
41e29def 2147L<perlpolicy> now contains the policy on compatibility and deprecation
d430b8e7 2148along with definitions of terms like "deprecation" (5.12.2).
5076a392 2149
41e29def 2150=head3 New descriptions in L<perldiag>
5076a392
FC
2151
2152The following existing diagnostics are now documented:
2153
2154=over 4
2155
2156=item *
2157
2158L<Ambiguous use of %c resolved as operator %c|perldiag/"Ambiguous use of %c resolved as operator %c">
2159
2160=item *
2161
2162L<Ambiguous use of %c{%s} resolved to %c%s|perldiag/"Ambiguous use of %c{%s} resolved to %c%s">
2163
2164=item *
2165
2166L<Ambiguous use of %c{%s%s} resolved to %c%s%s|perldiag/"Ambiguous use of %c{%s%s} resolved to %c%s%s">
2167
2168=item *
2169
2170L<Ambiguous use of -%s resolved as -&%s()|perldiag/"Ambiguous use of -%s resolved as -&%s()">
2171
2172=item *
2173
2174L<Invalid strict version format (%s)|perldiag/"Invalid strict version format (%s)">
2175
2176=item *
2177
2178L<Invalid version format (%s)|perldiag/"Invalid version format (%s)">
2179
2180=item *
2181
2182L<Invalid version object|perldiag/"Invalid version object">
2183
2184=back
2185
5076a392
FC
2186=head3 L<perlbook>
2187
41e29def 2188L<perlbook> has been expanded to cover many more popular books.
5076a392 2189
41e29def 2190=head3 C<SvTRUE> macro
5076a392 2191
41e29def
FC
2192The documentation for the C<SvTRUE> macro in
2193L<perlapi> was simply wrong in stating that
5076a392
FC
2194get-magic is not processed. It has been corrected.
2195
41e29def 2196=head3 L<perlvar> revamp
5076a392 2197
41e29def 2198L<perlvar> reorders the variables and groups them by topic. Each variable
5076a392 2199introduced after Perl 5.000 notes the first version in which it is
41e29def 2200available. L<perlvar> also has a new section for deprecated variables to
5076a392
FC
2201note when they were removed.
2202
41e29def 2203=head3 Array and hash slices in scalar context
5076a392 2204
41e29def 2205These are now documented in L<perldata>.
5076a392 2206
41e29def 2207=head3 C<use locale> and formats
5076a392
FC
2208
2209L<perlform> and L<perllocale> have been corrected to state that
2210C<use locale> affects formats.
2211
5076a392
FC
2212=head3 L<overload>
2213
5076a392
FC
2214L<overload>'s documentation has practically undergone a rewrite. It
2215is now much more straightforward and clear.
2216
41e29def 2217=head3 L<perlhack> and perlrepository revamp
5076a392
FC
2218
2219The L<perlhack> and perlrepository documents have been heavily edited and
2220split up into several new documents.
2221
2222The L<perlhack> document is now much shorter, and focuses on the Perl 5
2223development process and submitting patches to Perl. The technical content has
2224been moved to several new documents, L<perlsource>, L<perlinterp>,
2225L<perlhacktut>, and L<perlhacktips>. This technical content has only been
2226lightly edited.
2227
2228The perlrepository document has been renamed to L<perlgit>. This new document
2229is just a how-to on using git with the Perl source code. Any other content
2230that used to be in perlrepository has been moved to perlhack.
2231
41e29def 2232=head3 Time::Piece examples
5076a392
FC
2233
2234Examples in L<perlfaq4> have been updated to show the use of
41e29def 2235L<Time::Piece>.
5076a392
FC
2236
2237=head1 Diagnostics
2238
2239The following additions or changes have been made to diagnostic output,
2240including warnings and fatal error messages. For the complete list of
2241diagnostic messages, see L<perldiag>.
2242
2243=head2 New Diagnostics
2244
a593b319
FC
2245=head3 New Errors
2246
5076a392
FC
2247=over
2248
a593b319 2249=item Closure prototype called
5076a392 2250
a593b319
FC
2251This error occurs when a subroutine reference passed to an attribute
2252handler is called, if the subroutine is a closure [perl #68560].
5076a392 2253
a593b319 2254=item Insecure user-defined property %s
5076a392 2255
a593b319
FC
2256Perl detected tainted data when trying to compile a regular
2257expression that contains a call to a user-defined character property
2258function, i.e. C<\p{IsFoo}> or C<\p{InFoo}>.
2259See L<perlunicode/User-Defined Character Properties> and L<perlsec>.
5076a392 2260
a593b319 2261=item panic: gp_free failed to free glob pointer - something is repeatedly re-creating entries
5076a392 2262
a593b319
FC
2263This new error is triggered if a destructor called on an object in a
2264typeglob that is being freed creates a new typeglob entry containing an
2265object with a destructor that creates a new entry containing an object....
5076a392 2266
a593b319 2267=item Parsing code internal error (%s)
5076a392 2268
a593b319
FC
2269This new fatal error is produced when parsing
2270code supplied by an extension violates the
2271parser's API in a detectable way.
5076a392 2272
a593b319 2273=item refcnt: fd %d%s
5076a392 2274
a593b319
FC
2275This new error only occurs if a internal consistency check fails when a
2276pipe is about to be closed.
5076a392 2277
a593b319 2278=item Regexp modifier "/%c" may not appear twice
5076a392 2279
a593b319
FC
2280The regular expression pattern has one of the
2281mutually exclusive modifiers repeated.
5076a392 2282
a593b319 2283=item Regexp modifiers "/%c" and "/%c" are mutually exclusive
5076a392 2284
a593b319
FC
2285The regular expression pattern has more than one of the mutually
2286exclusive modifiers.
5076a392 2287
a593b319 2288=item Using !~ with %s doesn't make sense
5076a392 2289
a593b319 2290This error occurs when C<!~> is used with C<s///r> or C<y///r>.
5076a392 2291
a593b319 2292=back
5076a392 2293
a593b319 2294=head3 New Warnings
5076a392 2295
a593b319 2296=over
5076a392 2297
a593b319 2298=item "\b{" is deprecated; use "\b\{" instead
5076a392 2299
a593b319 2300=item "\B{" is deprecated; use "\B\{" instead
5076a392 2301
a593b319
FC
2302Use of an unescaped "{" immediately following a C<\b> or C<\B> is now
2303deprecated so as to reserve its use for Perl itself in a future release.
5076a392 2304
a593b319 2305=item Operation "%s" returns its argument for ...
5076a392 2306
a593b319
FC
2307Performing an operation requiring Unicode semantics (such as case-folding)
2308on a Unicode surrogate or a non-Unicode character now triggers a warning:
2309'Operation "%s" returns its argument for ...'.
5076a392 2310
a593b319
FC
2311=item Use of qw(...) as parentheses is deprecated
2312
2313See L</"Use of qw(...) as parentheses">, above, for details.
5076a392
FC
2314
2315=back
2316
2317=head2 Changes to Existing Diagnostics
2318
2319=over 4
2320
2321=item *
2322
4ed2cea4
FC
2323The "Variable $foo is not imported" warning that precedes a
2324C<strict 'vars'> error has now been assigned the "misc" category, so that
2325C<no warnings> will suppress it [perl #73712].
2326
2327=item *
2328
5076a392
FC
2329C<warn> and C<die> now produce 'Wide character' warnings when fed a
2330character outside the byte range if STDERR is a byte-sized handle.
2331
2332=item *
2333
2334The 'Layer does not match this perl' error message has been replaced with
a593b319 2335these more helpful messages [perl #73754]:
5076a392
FC
2336
2337=over 4
2338
2339=item *
2340
2341PerlIO layer function table size (%d) does not match size expected by this
2342perl (%d)
2343
2344=item *
2345
2346PerlIO layer instance size (%d) does not match size expected by this perl
2347(%d)
2348
2349=back
2350
5076a392
FC
2351=item *
2352
2353The "Found = in conditional" warning that is emitted when a constant is
2354assigned to a variable in a condition is now withheld if the constant is
2355actually a subroutine or one generated by C<use constant>, since the value
2356of the constant may not be known at the time the program is written
2357[perl #77762].
2358
2359=item *
2360
2361Previously, if none of the C<gethostbyaddr>, C<gethostbyname> and
2362C<gethostent> functions were implemented on a given platform, they would
2363all die with the message 'Unsupported socket function "gethostent" called',
2364with analogous messages for C<getnet*> and C<getserv*>. This has been
2365corrected.
2366
2367=item *
2368
a593b319
FC
2369The warning message about unrecognized regular expression escapes passed
2370through has been changed to include any literal '{' following the
2371two-character escape. E.g., "\q{" is now emitted instead of "\q".
5076a392
FC
2372
2373=back
2374
2375=head1 Utility Changes
2376
0b88cc74 2377=head3 L<perlbug>
5076a392
FC
2378
2379=over 4
2380
2381=item *
2382
0b88cc74
FC
2383L<perlbug> now looks in the EMAIL environment variable for a return address
2384if the REPLY-TO and REPLYTO variables are empty.
5076a392
FC
2385
2386=item *
2387
0b88cc74
FC
2388L<perlbug> did not previously generate a From: header, potentially
2389resulting in dropped mail. Now it does include that header.
5076a392
FC
2390
2391=item *
2392
0b88cc74 2393The user's address is now used as the return-path.
4ed2cea4 2394
0b88cc74
FC
2395Many systems these days don't have a valid Internet domain name and
2396perlbug@perl.org does not accept email with a return-path that does
2397not resolve. So the user's address is now passed to sendmail so it's
2398less likely to get stuck in a mail queue somewhere [perl #82996].
5076a392 2399
2c389f6c
FC
2400=item *
2401
d430b8e7
FC
2402L<perlbug> now always gives the reporter a chance to change the email
2403address it guesses for them (5.12.2).
2404
2405=item *
2406
2407L<perlbug> should no longer warn about uninitialized values when using the C<-d>
2408and C<-v> options (5.12.2).
2c389f6c 2409
5076a392
FC
2410=back
2411
0b88cc74 2412=head3 L<perl5db.pl>
5076a392 2413
0b88cc74 2414=over
5076a392
FC
2415
2416=item *
2417
0b88cc74
FC
2418The remote terminal works after forking and spawns new sessions - one
2419for each forked process.
5076a392
FC
2420
2421=back
2422
0b88cc74 2423=head3 L<ptargrep>
5076a392
FC
2424
2425=over 4
2426
2427=item *
2428
0b88cc74
FC
2429L<ptargrep> is a new utility to apply pattern matching to the contents of
2430files in a tar archive. It comes with C<Archive::Tar>.
5076a392
FC
2431
2432=back
2433
2434=head1 Configuration and Compilation
2435
61752d82
FC
2436See also L</"Naming fixes in Policy_sh.SH may invalidate Policy.sh">,
2437above.
2438
5076a392
FC
2439=over 4
2440
2441=item *
2442
87595b22
FC
2443CCINCDIR and CCLIBDIR for the mingw64
2444cross-compiler are now correctly under
5076a392
FC
2445$(CCHOME)\mingw\include and \lib rather than immediately below $(CCHOME).
2446
5076a392
FC
2447This means the 'incpath', 'libpth', 'ldflags', 'lddlflags' and
2448'ldflags_nolargefiles' values in Config.pm and Config_heavy.pl are now
87595b22 2449set correctly.
5076a392
FC
2450
2451=item *
2452
87595b22
FC
2453'make test.valgrind' has been adjusted to account for cpan/dist/ext
2454separation.
5076a392
FC
2455
2456=item *
2457
2458On compilers that support it, C<-Wwrite-strings> is now added to cflags by
2459default.
2460
2461=item *
2462
2463The C<Encode> module can now (once again) be included in a static Perl
2464build. The special-case handling for this situation got broken in Perl
24655.11.0, and has now been repaired.
2466
1e463951
FC
2467=item *
2468
2469The previous default size of a PerlIO buffer (4096 bytes) has been increased
2470to the larger of 8192 bytes and your local BUFSIZ. Benchmarks show that doubling
2471this decade-old default increases read and write performance in the neighborhood
2472of 25% to 50% when using the default layers of perlio on top of unix. To choose
2473a non-default size, such as to get back the old value or to obtain an even
2474larger value, configure with:
2475
2476 ./Configure -Accflags=-DPERLIOBUF_DEFAULT_BUFSIZ=N
2477
2478where N is the desired size in bytes; it should probably be a multiple of
2479your page size.
2480
d430b8e7
FC
2481=item *
2482
2483An "incompatible operand types" error in ternary expressions when building
2484with C<clang> has been fixed (5.12.2).
2485
2486=item *
2487
2488Perl now skips setuid C<File::Copy> tests on partitions it detects to be mounted
2489as C<nosuid> (5.12.2).
2490
5076a392
FC
2491=back
2492
5076a392
FC
2493=head1 Platform Support
2494
5076a392
FC
2495=head2 New Platforms
2496
5076a392
FC
2497=over 4
2498
2499=item AIX
2500
cdc10f43 2501Perl now builds on AIX 4.2 (5.12.1).
5076a392
FC
2502
2503=back
2504
2505=head2 Discontinued Platforms
2506
2507=over 4
2508
5076a392
FC
2509=item Apollo DomainOS
2510
2511The last vestiges of support for this platform have been excised from the
2512Perl distribution. It was officially discontinued in version 5.12.0. It had
2513not worked for years before that.
2514
2515=item MacOS Classic
2516
2517The last vestiges of support for this platform have been excised from the
2518Perl distribution. It was officially discontinued in an earlier version.
2519
2520=back
2521
2522=head2 Platform-Specific Notes
2523
d430b8e7
FC
2524=head3 AIX
2525
2526=over
2527
2528=item *
2529
2530F<README.aix> has been updated with information about the XL C/C++ V11 compiler
2531suite (5.12.2).
2532
2533=back
2534
2535=head3 ARM
2536
2537=over
2538
2539=item *
2540
2541The C<d_u32align> configuration probe on ARM has been fixed (5.12.2).
2542
2543=back
2544
554003a2 2545=head3 Cygwin
5076a392
FC
2546
2547=over 4
2548
2549=item *
2550
554003a2 2551MakeMaker has been updated to build man pages on cygwin.
5076a392
FC
2552
2553=item *
2554
554003a2
FC
2555Improved rebase behaviour
2556
2557If a dll is updated on cygwin the old imagebase address is reused.
2558This solves most rebase errors, especially when updating on core dll's.
2559See L<http://www.tishler.net/jason/software/rebase/rebase-2.4.2.README> for more information.
5076a392
FC
2560
2561=item *
2562
554003a2 2563Support for the standard cygwin dll prefix, which is e.g. needed for FFI's
5076a392
FC
2564
2565=item *
2566
554003a2 2567Updated build hints file
5076a392
FC
2568
2569=back
2570
cdc10f43
FC
2571=head3 FreeBSD 7
2572
2573=over
2574
2575=item *
2576
2577FreeBSD 7 no longer contains F</usr/bin/objformat>. At build time,
2578Perl now skips the F<objformat> check for versions 7 and higher and
2579assumes ELF (5.12.1).
2580
2581=back
2582
2583=head3 HP-UX
2584
2585=over
2586
2587=item *
2588
2589Perl now allows -Duse64bitint without promoting to use64bitall on HP-UX
2590(5.12.1).
2591
2592=back
2593
554003a2 2594=head3 IRIX
5076a392
FC
2595
2596Conversion of strings to floating-point numbers is now more accurate on
2597IRIX systems [perl #32380].
2598
554003a2 2599=head3 Mac OS X
5076a392
FC
2600
2601Early versions of Mac OS X (Darwin) had buggy implementations of the
2602C<setregid>, C<setreuid>, C<setrgid> and C<setruid> functions, so perl
2603would pretend they did not exist.
2604
2605These functions are now recognised on Mac OS 10.5 (Leopard; Darwin 9) and
2606higher, as they have been fixed [perl #72990].
2607
554003a2 2608=head3 MirBSD
5076a392 2609
554003a2
FC
2610Previously if you built perl with a shared libperl.so on MirBSD (the
2611default config), it would work up to the installation; however, once
2612installed, it would be unable to find libperl. So path handling is now
2613treated as in the other BSD dialects.
5076a392 2614
554003a2 2615=head3 NetBSD
5076a392 2616
554003a2
FC
2617The NetBSD hints file has been changed to make the system's malloc the
2618default.
5076a392 2619
554003a2 2620=head3 Recent OpenBSDs now use perl's malloc
5076a392 2621
554003a2
FC
2622OpenBSD E<gt> 3.7 has a new malloc implementation which is mmap-based
2623and as such can release memory back to the OS; however, perl's use of
2624this malloc causes a substantial slowdown so we now default to using
2625perl's malloc instead [perl #75742].
5076a392 2626
554003a2 2627=head3 OpenVOS
5076a392 2628
554003a2 2629perl now builds again with OpenVOS (formerly known as Stratus VOS)
5a553547 2630[perl #78132] (5.12.3).
5076a392 2631
554003a2 2632=head3 Solaris
5076a392 2633
554003a2 2634DTrace is now supported on Solaris. There used to be build failures, but
5a553547 2635these have been fixed [perl #73630] (5.12.3).
5076a392 2636
554003a2 2637=head3 VMS
5076a392
FC
2638
2639=over
2640
2641=item *
2642
cdc10f43
FC
2643It's now possible to build extensions on older (pre 7.3-2) VMS systems.
2644
2645DCL symbol length was limited to 1K up until about seven years or
2646so ago, but there was no particularly deep reason to prevent those
2647older systems from configuring and building Perl (5.12.1).
2648
2649=item *
2650
2651We fixed the previously-broken C<-Uuseperlio> build on VMS.
2652
2653We were checking a variable that doesn't exist in the non-default
2654case of disabling perlio. Now we only look at it when it exists (5.12.1).
2655
2656=item *
2657
2658We fixed the -Uuseperlio command-line option in configure.com.
2659
2660Formerly it only worked if you went through all the questions
2661interactively and explicitly answered no (5.12.1).
2662
2663=item *
2664
554003a2 2665C<PerlIOUnix_open> now honours the default permissions on VMS.
5076a392 2666
554003a2
FC
2667When C<perlio> became the default and C<unixio> became the default bottom layer,
2668the most common path for creating files from Perl became C<PerlIOUnix_open>,
2669which has always explicitly used C<0666> as the permission mask.
5076a392 2670
554003a2
FC
2671To avoid this, C<0777> is now passed as the permissions to C<open()>. In the
2672VMS CRTL, C<0777> has a special meaning over and above intersecting with the
2673current umask; specifically, it allows Unix syscalls to preserve native default
5a553547
FC
2674permissions (5.12.3).
2675
2676=item *
2677
2678Spurious record boundaries are no longer
2679introduced by the PerlIO layer during output (5.12.3).
5076a392
FC
2680
2681=item *
2682
554003a2
FC
2683The shortening of symbols longer than 31 characters in the C sources is
2684now done by the compiler rather than by xsubpp (which could only do so
2685for generated symbols in XS code).
5076a392
FC
2686
2687=item *
2688
554003a2
FC
2689Record-oriented files (record format variable or variable with fixed control)
2690opened for write by the perlio layer will now be line-buffered to prevent the
2691introduction of spurious line breaks whenever the perlio buffer fills up.
5076a392 2692
d430b8e7
FC
2693=item *
2694
2695F<git_version.h> is now installed on VMS. This was an oversight in v5.12.0 which
2696caused some extensions to fail to build (5.12.2).
2697
2698=item *
2699
2700Several memory leaks in L<stat()|perlfunc/"stat FILEHANDLE"> have been fixed (5.12.2).
2701
2702=item *
2703
2704A memory leak in C<Perl_rename()> due to a double allocation has been
2705fixed (5.12.2).
2706
2707=item *
2708
2709A memory leak in C<vms_fid_to_name()> (used by C<realpath()> and
2710C<realname()>) has been fixed (5.12.2).
2711
5076a392
FC
2712=back
2713
554003a2 2714=head3 Windows
5076a392 2715
5a1f7719
FC
2716See also L</"fork() emulation will not wait for signalled children"> and
2717L</"Perl source code is read in text mode on Windows">, above.
2718
5076a392
FC
2719=over 4
2720
2721=item *
2722
554003a2 2723Fixed build process for SDK2003SP1 compilers.
5076a392 2724
554003a2 2725=item *
5076a392 2726
01b1a9e4
FC
2727Compilation with Visual Studio 2010 is now supported.
2728
2729=item *
2730
554003a2
FC
2731When using old 32-bit compilers, the define C<_USE_32BIT_TIME_T> will now
2732be set in C<$Config{ccflags}>. This improves portability when compiling
2733XS extensions using new compilers, but for a perl compiled with old 32-bit
2734compilers.
5076a392
FC
2735
2736=item *
2737
554003a2
FC
2738C<$Config{gccversion}> is now set correctly when perl is built using the
2739mingw64 compiler from L<http://mingw64.org> [perl #73754].
5076a392 2740
554003a2
FC
2741=item *
2742
d430b8e7
FC
2743When building Perl with the mingw64 x64 cross-compiler C<incpath>,
2744C<libpth>, C<ldflags>, C<lddlflags> and C<ldflags_nolargefiles> values
2745in F<Config.pm> and F<Config_heavy.pl> were not previously being set
2746correctly because, with that compiler, the include and lib directories
2747are not immediately below C<$(CCHOME)> (5.12.2).
2748
2749=item *
2750
554003a2
FC
2751The build process proceeds more smoothly with mingw and dmake when
2752F<C:\MSYS\bin> is in the PATH, due to a C<Cwd> fix.
5076a392
FC
2753
2754=item *
2755
554003a2
FC
2756Support for building with Visual C++ 2010 is now underway, but is not yet
2757complete. See F<README.win32> or L<perlwin32> for more details.
5076a392 2758
554003a2
FC
2759=item *
2760
2761The option to use an externally-supplied C<crypt()>, or to build with no
2762C<crypt()> at all, has been removed. Perl supplies its own C<crypt()>
2763implementation for Windows, and the political situation that required
2764this part of the distribution to sometimes be omitted is long gone.
5076a392
FC
2765
2766=back
2767
2768=head1 Internal Changes
2769
1e463951 2770=head2 New APIs
5076a392 2771
1e463951 2772=head3 CLONE_PARAMS structure added to ease correct thread creation
5076a392 2773
1e463951
FC
2774Modules that create threads should now create C<CLONE_PARAMS> structures
2775by calling the new function C<Perl_clone_params_new()>, and free them with
2776C<Perl_clone_params_del()>. This will ensure compatibility with any future
2777changes to the internals of the C<CLONE_PARAMS> structure layout, and that
2778it is correctly allocated and initialised.
5076a392 2779
1e463951 2780=head3 New parsing functions
5076a392 2781
1e463951
FC
2782Several functions have been added for parsing statements or multiple
2783statements:
5076a392 2784
1e463951 2785=over
5076a392
FC
2786
2787=item *
2788
1e463951 2789C<parse_fullstmt> parses a complete Perl statement.
5076a392
FC
2790
2791=item *
2792
1e463951
FC
2793C<parse_stmtseq> parses a sequence of statements, up
2794to closing brace or EOF.
5076a392
FC
2795
2796=item *
2797
1e463951 2798C<parse_block> parses a block [perl #78222].
5076a392
FC
2799
2800=item *
2801
1e463951
FC
2802C<parse_barestmt> parses a statement
2803without a label.
5076a392
FC
2804
2805=item *
2806
1e463951 2807C<parse_label> parses a statement label, separate from statements.
5076a392 2808
1e463951 2809=back
5076a392 2810
1e463951
FC
2811The
2812L<C<parse_fullexpr()>|perlapi/parse_fullexpr>,
2813L<C<parse_listexpr()>|perlapi/parse_listexpr>,
2814L<C<parse_termexpr()>|perlapi/parse_termexpr>, and
2815L<C<parse_arithexpr()>|perlapi/parse_arithexpr>
2816functions have been added to the API. They perform
2817recursive-descent parsing of expressions at various precedence levels.
2818They are expected to be used by syntax plugins.
5076a392 2819
1e463951 2820See L<perlapi> for details.
5076a392 2821
1e463951 2822=head3 Hints hash API
5076a392 2823
1e463951
FC
2824A new C API for introspecting the hinthash C<%^H> at runtime has been
2825added. See C<cop_hints_2hv>, C<cop_hints_fetchpvn>, C<cop_hints_fetchpvs>,
2826C<cop_hints_fetchsv>, and C<hv_copy_hints_hv> in L<perlapi> for details.
5076a392 2827
1e463951
FC
2828A new, experimental API has been added for accessing the internal
2829structure that Perl uses for C<%^H>. See the functions beginning with
2830C<cophh_> in L<perlapi>.
5076a392 2831
1e463951 2832=head3 C interface to C<caller()>
5076a392 2833
1e463951
FC
2834The C<caller_cx> function has been added as an XSUB-writer's equivalent of
2835C<caller()>. See L<perlapi> for details.
5076a392 2836
1e463951 2837=head3 Custom per-subroutine check hooks
5076a392 2838
1e463951
FC
2839XS code in an extension module can now annotate a subroutine (whether
2840implemented in XS or in Perl) so that nominated XS code will be called
2841at compile time (specifically as part of op checking) to change the op
2842tree of that subroutine. The compile-time check function (supplied by
2843the extension module) can implement argument processing that can't be
2844expressed as a prototype, generate customised compile-time warnings,
2845perform constant folding for a pure function, inline a subroutine
2846consisting of sufficiently simple ops, replace the whole call with a
2847custom op, and so on. This was previously all possible by hooking the
2848C<entersub> op checker, but the new mechanism makes it easy to tie the
2849hook to a specific subroutine. See L<perlapi/cv_set_call_checker>.
5076a392 2850
1e463951
FC
2851To help in writing custom check hooks, several subtasks within standard
2852C<entersub> op checking have been separated out and exposed in the API.
5076a392 2853
1e463951 2854=head3 Improved support for custom OPs
5076a392 2855
1e463951
FC
2856Custom ops can now be registered with the new C<custom_op_register> C
2857function and the C<XOP> structure. This will make it easier to add new
2858properties of custom ops in the future. Two new properties have been added
2859already, C<xop_class> and C<xop_peep>.
5076a392 2860
1e463951
FC
2861C<xop_class> is one of the OA_*OP constants, and allows L<B> and other
2862introspection mechanisms to work with custom ops
2863that aren't BASEOPs. C<xop_peep> is a pointer to
2864a function that will be called for ops of this
2865type from C<Perl_rpeep>.
5076a392 2866
1e463951
FC
2867See L<perlguts/Custom Operators> and L<perlapi/Custom Operators> for more
2868detail.
5076a392 2869
1e463951
FC
2870The old C<PL_custom_op_names>/C<PL_custom_op_descs> interface is still
2871supported but discouraged.
5076a392 2872
1e463951 2873=head3 Scope hooks
5076a392 2874
1e463951
FC
2875It is now possible for XS code to hook into Perl's lexical scope
2876mechanism at compile time, using the new C<Perl_blockhook_register>
2877function. See L<perlguts/"Compile-time scope hooks">.
5076a392 2878
1e463951 2879=head3 The recursive part of the peephole optimizer is now hookable
5076a392
FC
2880
2881In addition to C<PL_peepp>, for hooking into the toplevel peephole optimizer, a
2882C<PL_rpeepp> is now available to hook into the optimizer recursing into
2883side-chains of the optree.
2884
1e463951 2885=head3 New non-magical variants of existing functions
5076a392 2886
1e463951
FC
2887The following functions/macros have been added to the API. The C<*_nomg>
2888macros are equivalent to their non-_nomg variants, except that they ignore
2889get-magic. Those ending in C<_flags> allow one to specify whether
2890get-magic is processed.
5076a392 2891
1e463951
FC
2892 sv_2bool_flags
2893 SvTRUE_nomg
2894 sv_2nv_flags
2895 SvNV_nomg
2896 sv_cmp_flags
2897 sv_cmp_locale_flags
2898 sv_eq_flags
2899 sv_collxfrm_flags
5076a392 2900
1e463951 2901In some of these cases, the non-_flags functions have
5076a392
FC
2902been replaced with wrappers around the new functions.
2903
1e463951 2904=head3 pv/pvs/sv versions of existing functions
5076a392 2905
1e463951 2906Many functions ending with pvn now have equivalent pv/pvs/sv versions.
5076a392 2907
1e463951 2908=head3 List op-building functions
5076a392 2909
1e463951
FC
2910List op-building functions have been added to the
2911API. See L<op_append_elem|perlapi/op_append_elem>,
2912L<op_append_list|perlapi/op_append_list>, and
2913L<op_prepend_elem|perlapi/op_prepend_elem> in L<perlapi>.
5076a392 2914
1e463951 2915=head3 C<LINKLIST>
5076a392 2916
1e463951
FC
2917The L<LINKLIST|perlapi/LINKLIST> macro, part of op building that
2918constructs the execution-order op chain, has been added to the API.
5076a392 2919
1e463951 2920=head3 Localisation functions
5076a392 2921
1e463951
FC
2922The C<save_freeop>, C<save_op>, C<save_pushi32ptr> and C<save_pushptrptr>
2923functions have been added to the API.
5076a392 2924
1e463951 2925=head3 Stash names
5076a392 2926
1e463951
FC
2927A stash can now have a list of effective names in addition to its usual
2928name. The first effective name can be accessed via the C<HvENAME> macro,
2929which is now the recommended name to use in MRO linearisations (C<HvNAME>
2930being a fallback if there is no C<HvENAME>).
5076a392 2931
1e463951
FC
2932These names are added and deleted via C<hv_ename_add> and
2933C<hv_ename_delete>. These two functions are I<not> part of the API.
5076a392 2934
1e463951 2935=head3 New functions for finding and removing magic
5076a392 2936
1e463951
FC
2937The L<C<mg_findext()>|perlapi/mg_findext> and
2938L<C<sv_unmagicext()>|perlapi/sv_unmagicext>
2939functions have been added to the API.
2940They allow extension authors to find and remove magic attached to
2941scalars based on both the magic type and the magic virtual table, similar to how
2942C<sv_magicext()> attaches magic of a certain type and with a given virtual table
2943to a scalar. This eliminates the need for extensions to walk the list of
2944C<MAGIC> pointers of an C<SV> to find the magic that belongs to them.
5076a392 2945
1e463951 2946=head3 C<find_rundefsv>
5076a392 2947
1e463951
FC
2948This function returns the SV representing C<$_>, whether it's lexical
2949or dynamic.
5076a392 2950
1e463951 2951=head3 C<Perl_croak_no_modify>
5076a392 2952
1e463951
FC
2953C<Perl_croak_no_modify()> is short-hand for
2954C<Perl_croak("%s", PL_no_modify)>.
5076a392 2955
1e463951 2956=head3 C<PERL_STATIC_INLINE> define
5076a392 2957
1e463951
FC
2958The C<PERL_STATIC_INLINE> define has been added to provide the best-guess
2959incantation to use for static inline functions, if the C compiler supports
2960C99-style static inline. If it doesn't, it'll give a plain C<static>.
5076a392 2961
1e463951
FC
2962C<HAS_STATIC_INLINE> can be used to check if the compiler actually supports
2963inline functions.
5076a392 2964
1e463951 2965=head3 New C<pv_escape> option for hexadecimal escapes
5076a392 2966
1e463951
FC
2967A new option, C<PERL_PV_ESCAPE_NONASCII>, has been added to C<pv_escape> to
2968dump all characters above ASCII in hexadecimal. Before, one could get all
2969characters as hexadecimal or the Latin1 non-ASCII as octal.
5076a392 2970
1e463951 2971=head3 C<lex_start>
5076a392 2972
1e463951 2973C<lex_start> has been added to the API, but is considered experimental.
5076a392 2974
1e463951 2975=head3 C<op_scope()> and C<op_lvalue()>
5076a392 2976
1e463951
FC
2977The C<op_scope()> and C<op_lvalue()> functions have been added to the API,
2978but are considered experimental.
5076a392 2979
1e463951 2980=head2 C API Changes
5076a392 2981
1e463951 2982=head3 C<PERL_POLLUTE> has been removed
5076a392 2983
1e463951
FC
2984The option to define C<PERL_POLLUTE> to expose older 5.005 symbols for
2985backwards compatibility has been removed. It's use was always discouraged,
2986and MakeMaker contains a more specific escape hatch:
5076a392 2987
1e463951 2988 perl Makefile.PL POLLUTE=1
5076a392 2989
1e463951
FC
2990This can be used for modules that have not been upgraded to 5.6 naming
2991conventions (and really should be completely obsolete by now).
5076a392 2992
1e463951 2993=head3 Check API compatibility when loading XS modules
5076a392 2994
1e463951
FC
2995When perl's API changes in incompatible ways (which usually happens between
2996major releases), XS modules compiled for previous versions of perl will not
2997work anymore. They will need to be recompiled against the new perl.
5076a392 2998
1e463951
FC
2999In order to ensure that modules are recompiled, and to prevent users from
3000accidentally loading modules compiled for old perls into newer ones, the
3001C<XS_APIVERSION_BOOTCHECK> macro has been added. That macro, which is
3002called when loading every newly compiled extension, compares the API
3003version of the running perl with the version a module has been compiled for
3004and raises an exception if they don't match.
5076a392 3005
1e463951 3006=head3 Perl_fetch_cop_label
5076a392 3007
1e463951
FC
3008The first argument of the C API function C<Perl_fetch_cop_label> has changed
3009from C<struct refcounted he *> to C<COP *>, to insulate the user from
3010implementation details.
5076a392 3011
1e463951
FC
3012This API function was marked as "may change", and likely isn't in use outside
3013the core. (Neither an unpacked CPAN, nor Google's codesearch, finds any other
3014references to it.)
5076a392 3015
1e463951 3016=head3 GvCV() and GvGP() are no longer lvalues
5076a392 3017
1e463951
FC
3018The new GvCV_set() and GvGP_set() macros are now provided to replace
3019assignment to those two macros.
5076a392 3020
1e463951
FC
3021This allows a future commit to eliminate some backref magic between GV
3022and CVs, which will require complete control over assignment to the
3023gp_cv slot.
5076a392 3024
1e463951 3025=head3 CvGV() is no longer an lvalue
5076a392 3026
1e463951
FC
3027Under some circumstances, the C<CvGV()> field of a CV is now
3028reference-counted. To ensure consistent behaviour, direct assignment to
3029it, for example C<CvGV(cv) = gv> is now a compile-time error. A new macro,
3030C<CvGV_set(cv,gv)> has been introduced to perform this operation
3031safely. Note that modification of this field is not part of the public
3032API, regardless of this new macro (and despite its being listed in this section).
5076a392 3033
1e463951 3034=head3 CvSTASH() is no longer an lvalue
5076a392 3035
1e463951
FC
3036The C<CvSTASH()> macro can now only be used as an rvalue. C<CvSTASH_set()>
3037has been added to replace assignment to C<CvSTASH()>. This is to ensure
3038that backreferences are handled properly. These macros are not part of the
3039API.
5076a392 3040
1e463951 3041=head3 Calling conventions for C<newFOROP> and C<newWHILEOP>
5076a392 3042
1e463951
FC
3043The way the parser handles labels has been cleaned up and refactored. As a
3044result, the C<newFOROP()> constructor function no longer takes a parameter
3045stating what label is to go in the state op.
5076a392 3046
1e463951
FC
3047The C<newWHILEOP()> and C<newFOROP()> functions no longer accept a line
3048number as a parameter.
5076a392 3049
1e463951 3050=head3 Flags passed to C<uvuni_to_utf8_flags> and C<utf8n_to_uvuni>
5076a392 3051
1e463951
FC
3052Some of the flags parameters to uvuni_to_utf8_flags() and
3053utf8n_to_uvuni() have changed. This is a result of Perl's now allowing
5076a392
FC
3054internal storage and manipulation of code points that are problematic
3055in some situations. Hence, the default actions for these functions has
3056been complemented to allow these code points. The new flags are
3057documented in L<perlapi>. Code that requires the problematic code
483b16f3 3058points to be rejected needs to change to use the new flags. Some flag
5076a392
FC
3059names are retained for backward source compatibility, though they do
3060nothing, as they are now the default. However the flags
3061C<UNICODE_ALLOW_FDD0>, C<UNICODE_ALLOW_FFFF>, C<UNICODE_ILLEGAL>, and
3062C<UNICODE_IS_ILLEGAL> have been removed, as they stem from a
3063fundamentally broken model of how the Unicode non-character code points
3064should be handled, which is now described in
3065L<perlunicode/Non-character code points>. See also L</Selected Bug Fixes>.
3066
1e463951 3067XXX Which bugs in particular? Selected Bug Fixes is too long for this link
483b16f3
KW
3068to be meaningful right now
3069I don't see the bugs in that section currently -- khw
5076a392 3070
1e463951 3071=head2 Deprecated C APIs
5076a392 3072
1e463951 3073=over
5076a392 3074
1e463951 3075=item C<Perl_ptr_table_clear>
5076a392 3076
1e463951
FC
3077C<Perl_ptr_table_clear> is no longer part of Perl's public API. Calling it
3078now generates a deprecation warning, and it will be removed in a future
3079release.
5076a392 3080
1e463951 3081=item C<sv_compile_2op>
5076a392 3082
1e463951
FC
3083The C<sv_compile_2op()> API function is now deprecated. Searches suggest
3084that nothing on CPAN is using it, so this should have zero impact.
5076a392 3085
1e463951
FC
3086It attempted to provide an API to compile code down to an optree, but failed
3087to bind correctly to lexicals in the enclosing scope. It's not possible to
3088fix this problem within the constraints of its parameters and return value.
5076a392 3089
1e463951 3090=item C<find_rundefsvoffset>
5076a392 3091
1e463951
FC
3092The C<find_rundefsvoffset> function has been deprecated. It appeared that
3093its design was insufficient for reliably getting the lexical C<$_> at
3094run-time.
5076a392 3095
1e463951
FC
3096Use the new C<find_rundefsv> function or the C<UNDERBAR> macro
3097instead. They directly return the right SV representing C<$_>, whether it's
3098lexical or dynamic.
5076a392 3099
1e463951 3100=item C<CALL_FPTR> and C<CPERLscope>
5076a392 3101
1e463951
FC
3102Those are left from an old implementation of C<MULTIPLICITY> using C++ objects,
3103which was removed in Perl 5.8. Nowadays these macros do exactly nothing, so
3104they shouldn't be used anymore.
5076a392 3105
1e463951
FC
3106For compatibility, they are still defined for external C<XS> code. Only
3107extensions defining C<PERL_CORE> must be updated now.
5076a392 3108
1e463951 3109=back
5076a392 3110
1e463951 3111=head2 Other Internal Changes
5076a392 3112
1e463951 3113=head3 Stack unwinding
5076a392 3114
1e463951
FC
3115The protocol for unwinding the C stack at the last stage of a C<die>
3116has changed how it identifies the target stack frame. This now uses
3117a separate variable C<PL_restartjmpenv>, where previously it relied on
3118the C<blk_eval.cur_top_env> pointer in the C<eval> context frame that
3119has nominally just been discarded. This change means that code running
3120during various stages of Perl-level unwinding no longer needs to take
3121care to avoid destroying the ghost frame.
5076a392 3122
1e463951 3123=head3 Scope stack entries
5076a392 3124
1e463951
FC
3125The format of entries on the scope stack has been changed, resulting in a
3126reduction of memory usage of about 10%. In particular, the memory used by
3127the scope stack to record each active lexical variable has been halved.
5076a392 3128
1e463951 3129=head3 Memory allocation for pointer tables
5076a392 3130
1e463951
FC
3131Memory allocation for pointer tables has been changed. Previously
3132C<Perl_ptr_table_store> allocated memory from the same arena system as
3133C<SV> bodies and C<HE>s, with freed memory remaining bound to those arenas
3134until interpreter exit. Now it allocates memory from arenas private to the
3135specific pointer table, and that memory is returned to the system when
3136C<Perl_ptr_table_free> is called. Additionally, allocation and release are
3137both less CPU intensive.
5076a392 3138
1e463951 3139=head3 C<UNDERBAR>
5076a392 3140
1e463951
FC
3141The C<UNDERBAR> macro now calls C<find_rundefsv>. C<dUNDERBAR> is now a
3142noop but should still be used to ensure past and future compatibility.
5076a392 3143
1e463951 3144=head3 String comparison routines renamed
5076a392 3145
1e463951
FC
3146The ibcmp_* functions have been renamed and are now called foldEQ,
3147foldEQ_locale and foldEQ_utf8. The old names are still available as
3148macros.
3149
3150=head3 C<chop> and C<chomp> implementations merged
3151
3152The opcode bodies for C<chop> and C<chomp> and for C<schop> and C<schomp>
3153have been merged. The implementation functions C<Perl_do_chop()> and
3154C<Perl_do_chomp()>, never part of the public API, have been merged and
3155moved to a static function in F<pp.c>. This shrinks the perl binary
3156slightly, and should not affect any code outside the core (unless it is
3157relying on the order of side effects when C<chomp> is passed a I<list> of
3158values).
5076a392
FC
3159
3160=head1 Selected Bug Fixes
3161
e8e35311
FC
3162=head2 I/O
3163
5076a392
FC
3164=over 4
3165
3166=item *
3167
e8e35311 3168Perl no longer produces this warning:
a593b319
FC
3169
3170 $ perl -we 'open my $f, ">", \my $x; binmode $f, "scalar"'
3171 Use of uninitialized value in binmode at -e line 1.
3172
3173=item *
3174
e8e35311
FC
3175Opening a glob reference via C<< open $fh, "E<gt>", \*glob >> will no longer
3176cause the glob to be corrupted when the filehandle is printed to. This would
3177cause perl to crash whenever the glob's contents were accessed
3178[perl #77492].
4ed2cea4
FC
3179
3180=item *
3181
e8e35311
FC
3182PerlIO no longer crashes when called recursively, e.g., from a signal
3183handler. Now it just leaks memory [perl #75556].
4ed2cea4
FC
3184
3185=item *
3186
e8e35311
FC
3187Most I/O functions were not warning for unopened handles unless the
3188'closed' and 'unopened' warnings categories were both enabled. Now only
3189C<use warnings 'unopened'> is necessary to trigger these warnings (as was
438c239f 3190always meant to be the case).
4ed2cea4
FC
3191
3192=item *
3193
438c239f 3194There have been several fixes to PerlIO layers:
e8e35311 3195
438c239f
FC
3196When C<binmode FH, ":crlf"> pushes the C<:crlf> layer on top of the stack,
3197it no longer enables crlf layers lower in the stack, to avoid unexpected
3198results [perl #38456].
4ed2cea4 3199
438c239f
FC
3200Opening a file in C<:raw> mode now does what it advertises to do (first
3201open the file, then binmode it), instead of simply leaving off the top
3202layer [perl #80764].
5076a392 3203
438c239f
FC
3204The three layers C<:pop>, C<:utf8> and C<:bytes> didn't allow stacking when
3205opening a file. For example
e8e35311 3206this:
5076a392 3207
e8e35311 3208 open FH, '>:pop:perlio', 'some.file' or die $!;
5076a392 3209
438c239f
FC
3210Would throw an error: "Invalid argument". This has been fixed in this
3211release [perl #82484].
5076a392 3212
e8e35311
FC
3213=back
3214
3215=head2 Regular Expression Bug Fixes
3216
3217=over
5076a392
FC
3218
3219=item *
3220
e8e35311
FC
3221The regular expression engine no longer loops when matching
3222C<"\N{LATIN SMALL LIGATURE FF}" =~ /f+/i> and similar expressions
cdc10f43 3223[perl #72998] (5.12.1).
5076a392
FC
3224
3225=item *
3226
e8e35311
FC
3227The trie runtime code should no longer allocate massive amounts of memory,
3228fixing #74484.
5076a392
FC
3229
3230=item *
3231
438c239f
FC
3232Syntax errors in C<< (?{...}) >> blocks no longer cause panic messages
3233[perl #2353].
5076a392
FC
3234
3235=item *
3236
438c239f
FC
3237A pattern like C<(?:(o){2})?> no longer causes a "panic" error
3238[perl #39233].
5076a392
FC
3239
3240=item *
3241
438c239f 3242A fatal error in regular expressions containing C<(.*?)> when processing
d430b8e7 3243UTF-8 data has been fixed [perl #75680] (5.12.2).
5076a392
FC
3244
3245=item *
3246
e8e35311 3247An erroneous regular expression engine optimisation that caused regex verbs like
438c239f 3248C<*COMMIT> sometimes to be ignored has been removed.
5076a392
FC
3249
3250=item *
3251
e8e35311
FC
3252The regular expression bracketed character class C<[\8\9]> was effectively the
3253same as C<[89\000]>, incorrectly matching a NULL character. It also gave
3254incorrect warnings that the C<8> and C<9> were ignored. Now C<[\8\9]> is the
3255same as C<[89]> and gives legitimate warnings that C<\8> and C<\9> are
3256unrecognized escape sequences, passed-through.
5076a392
FC
3257
3258=item *
3259
e8e35311
FC
3260A regular expression match in the right-hand side of a global substitution
3261(C<s///g>) that is in the same scope will no longer cause match variables
3262to have the wrong values on subsequent iterations. This can happen when an
3263array or hash subscript is interpolated in the right-hand side, as in
3264C<s|(.)|@a{ print($1), /./ }|g> [perl #19078].
5076a392
FC
3265
3266=item *
3267
438c239f
FC
3268Several cases in which characters in the Latin-1 non-ASCII range (0x80 to
32690xFF) used not to match themselves or used to match both a character class
3270and its complement have been fixed. For instance, U+00E2 could match both
3271C<\w> and C<\W> [perl #78464] [perl #18281] [perl #60156].
5076a392
FC
3272
3273=item *
3274
e8e35311
FC
3275Matching a Unicode character against an alternation containing characters
3276that happened to match continuation bytes in the former's UTF8
3277representation (C<qq{\x{30ab}} =~ /\xab|\xa9/>) would cause erroneous
3278warnings [perl #70998].
5076a392
FC
3279
3280=item *
3281
e8e35311
FC
3282The trie optimisation was not taking empty groups into account, preventing
3283'foo' from matching C</\A(?:(?:)foo|bar|zot)\z/> [perl #78356].
5076a392
FC
3284
3285=item *
3286
e8e35311
FC
3287A pattern containing a C<+> inside a lookahead would sometimes cause an
3288incorrect match failure in a global match (e.g., C</(?=(\S+))/g>)
3289[perl #68564].
5076a392
FC
3290
3291=item *
3292
e8e35311
FC
3293A regular expression optimisation would sometimes cause a match with a
3294C<{n,m}> quantifier to fail when it should match [perl #79152].
5076a392
FC
3295
3296=item *
3297
e8e35311 3298Case insensitive matching in regular expressions compiled under C<use
438c239f
FC
3299locale> now works much more sanely when the pattern or
3300target string is encoded internally in
3301UTF8. Previously, under these conditions the localeness
e8e35311
FC
3302was completely lost. Now, code points above 255 are treated as Unicode,
3303but code points between 0 and 255 are treated using the current locale
438c239f
FC
3304rules, regardless of whether the pattern or the string is encoded in UTF8.
3305The few case-insensitive matches that cross the 255/256 boundary are not
e8e35311
FC
3306allowed. For example, 0xFF does not caselessly match the character at
33070x178, LATIN CAPITAL LETTER Y WITH DIAERESIS, because 0xFF may not be
3308LATIN SMALL LETTER Y in the current locale, and Perl has no way of
3309knowing if that character even exists in the locale, much less what code
3310point it is.
5076a392
FC
3311
3312=item *
3313
e8e35311
FC
3314The C<(?|...)> regular expression construct no longer crashes if the final
3315branch has more sets of capturing parentheses than any other branch. This
3316was fixed in Perl 5.10.1 for the case of a single branch, but that fix did
3317not take multiple branches into account [perl #84746].
5076a392
FC
3318
3319=item *
3320
e8e35311
FC
3321A bug has been fixed in the implementation of C<{...}> quantifiers in
3322regular expressions that prevented the code block in
3323C</((\w+)(?{ print $2 })){2}/> from seeing the C<$2> sometimes
3324[perl #84294].
5076a392 3325
e8e35311 3326=back
5076a392 3327
e8e35311
FC
3328=head2 Syntax/Parsing Bugs
3329
3330=over
5076a392
FC
3331
3332=item *
3333
e8e35311 3334C<when(scalar){...}> no longer crashes, but produces a syntax error
cdc10f43 3335[perl #74114] (5.12.1).
5076a392
FC
3336
3337=item *
3338
e8e35311
FC
3339A label right before a string eval (C<foo: eval $string>) no longer causes
3340the label to be associated also with the first statement inside the eval
3341[perl #74290] (5.12.1).
5076a392
FC
3342
3343=item *
3344
b2c076b5 3345The C<no 5.13.2;> form of C<no> no longer tries to turn on features or
d430b8e7 3346pragmata (i.e., strict) [perl #70075] (5.12.2).
5076a392
FC
3347
3348=item *
3349
b2c076b5
FC
3350C<BEGIN {require 5.12.0}> now behaves as documented, rather than behaving
3351identically to C<use 5.12.0;>. Previously, C<require> in a C<BEGIN> block
3352was erroneously executing the C<use feature ':5.12.0'> and
3353C<use strict;> behaviour, which only C<use> was documented to
3354provide [perl #69050].
5076a392
FC
3355
3356=item *
3357
5076a392
FC
3358A regression introduced in Perl 5.12.0, making
3359C<< my $x = 3; $x = length(undef) >> result in C<$x> set to C<3> has been
d430b8e7 3360fixed. C<$x> will now be C<undef> [perl #85508] (5.12.2).
b2c076b5
FC
3361
3362=item *
3363
3364When strict 'refs' mode is off, C<%{...}> in rvalue context returns
3365C<undef> if its argument is undefined. An optimisation introduced in perl
33665.12.0 to make C<keys %{...}> faster when used as a boolean did not take
3367this into account, causing C<keys %{+undef}> (and C<keys %$foo> when
3368C<$foo> is undefined) to be an error, which it should only be in strict
3369mode [perl #81750].
5076a392
FC
3370
3371=item *
3372
e8e35311 3373Constant-folding used to cause
5076a392 3374
e8e35311 3375 $text =~ ( 1 ? /phoo/ : /bear/)
5076a392 3376
e8e35311
FC
3377to turn into
3378
3379 $text =~ /phoo/
3380
3381at compile time. Now it correctly matches against C<$_> [perl #20444].
5076a392
FC
3382
3383=item *
3384
e8e35311
FC
3385Parsing Perl code (either with string C<eval> or by loading modules) from
3386within a C<UNITCHECK> block no longer causes the interpreter to crash
3387[perl #70614].
5076a392
FC
3388
3389=item *
3390
b2c076b5
FC
3391String evals no longer fail after 2 billion scopes have been
3392compiled [perl #83364].
3393
3394=item *
3395
e8e35311
FC
3396The parser no longer hangs when encountering certain Unicode characters,
3397such as U+387 [perl #74022].
5076a392
FC
3398
3399=item *
3400
b2c076b5
FC
3401Several contexts no longer allow a Unicode character to begin a word
3402that should never begin words, for an example an accent that must follow
3403another character previously could precede all other characters.
5076a392
FC
3404
3405=item *
3406
e8e35311
FC
3407Defining a constant with the same name as one of perl's special blocks
3408(e.g., INIT) stopped working in 5.12.0, but has now been fixed
3409[perl #78634].
5076a392
FC
3410
3411=item *
3412
e8e35311
FC
3413A reference to a literal value used as a hash key (C<$hash{\"foo"}>) used
3414to be stringified, even if the hash was tied [perl #79178].
5076a392
FC
3415
3416=item *
3417
e8e35311
FC
3418A closure containing an C<if> statement followed by a constant or variable
3419is no longer treated as a constant [perl #63540].
5076a392
FC
3420
3421=item *
3422
e8e35311
FC
3423C<state> can now be used with attributes. It used to mean the same thing as
3424C<my> if attributes were present [perl #68658].
5076a392
FC
3425
3426=item *
3427
e8e35311
FC
3428Expressions like C<< @$a > 3 >> no longer cause C<$a> to be mentioned in
3429the "Use of uninitialized value in numeric gt" warning when C<$a> is
3430undefined (since it is not part of the C<E<gt>> expression, but the operand
3431of the C<@>) [perl #72090].
5076a392
FC
3432
3433=item *
3434
e8e35311
FC
3435Accessing an element of a package array with a hard-coded number (as
3436opposed to an arbitrary expression) would crash if the array did not exist.
3437Usually the array would be autovivified during compilation, but typeglob
3438manipulation could remove it, as in these two cases which used to crash:
5076a392 3439
e8e35311
FC
3440 *d = *a; print $d[0];
3441 undef *d; print $d[0];
5076a392 3442
2c389f6c
FC
3443=item *
3444
3445The C<-C> command line option, when used on the shebang line, can now be
3446followed by other options [perl #72434].
3447
3448=item *
3449
3450The C<B> module was returning C<B::OP>s instead of C<B::LOGOP>s for C<entertry> [perl #80622].
3451This was due to a bug in the perl core, not in C<B> itself.
3452
e8e35311 3453=back
5076a392 3454
e262cb24
FC
3455=head2 Stashes, Globs and Method Lookup
3456
3457Perl 5.10.0 introduced a new internal mechanism for caching MROs (method
3458resolution orders, or lists of parent classes; aka "isa" caches) to make
3459method lookup faster (so @ISA arrays would not have to be searched
3460repeatedly). Unfortunately, this brought with it quite a few bugs. Almost
3461all of these have been fixed now, along with a few MRO-related bugs that
3462existed before 5.10.0:
3463
3464=over
3465
3466=item *
3467
3468The following used to have erratic effects on method resolution, because
3469the "isa" caches were not reset or otherwise ended up listing the wrong
3470classes. These have been fixed.
3471
3472=over
3473
3474=item Aliasing packages by assigning to globs [perl #77358]
3475
3476=item Deleting packages by deleting their containing stash elements
3477
3478=item Undefining the glob containing a package (C<undef *Foo::>)
3479
3480=item Undefining an ISA glob (C<undef *Foo::ISA>)
3481
3482=item Deleting an ISA stash element (C<delete $Foo::{ISA}>)
3483
3484=item Sharing @ISA arrays between classes (via C<*Foo::ISA = \@Bar::ISA> or
3485C<*Foo::ISA = *Bar::ISA>) [perl #77238]
3486
3487=back
3488
3489C<undef *Foo::ISA> would even stop a new C<@Foo::ISA> array from updating
3490caches.
3491
3492=item *
3493
3494Typeglob assignments would crash if the glob's stash no longer existed, so
3495long as the glob assigned to was named 'ISA' or the glob on either side of
3496the assignment contained a subroutine.
3497
3498=item *
3499
3500C<PL_isarev>, which is accessible to Perl via C<mro::get_isarev> is now
3501updated properly when packages are deleted or removed from the C<@ISA> of
3502other classes. This allows many packages to be created and deleted without
3503causing a memory leak [perl #75176].
3504
3505=back
3506
3507In addition, various other bugs related to typeglobs and stashes have been
3508fixed:
5076a392 3509
e8e35311 3510=over
5076a392
FC
3511
3512=item *
3513
e8e35311 3514Some work has been done on the internal pointers that link between symbol
e262cb24 3515tables (stashes), typeglobs and subroutines. This has the effect that
e8e35311
FC
3516various edge cases related to deleting stashes or stash entries (e.g.
3517<%FOO:: = ()>), and complex typeglob or code reference aliasing, will no
3518longer crash the interpreter.
5076a392
FC
3519
3520=item *
3521
e262cb24
FC
3522Assigning a reference to a glob copy now assigns to a glob slot instead of
3523overwriting the glob with a scalar [perl #1804] [perl #77508].
5076a392
FC
3524
3525=item *
3526
e8e35311
FC
3527A bug when replacing the glob of a loop variable within the loop has been fixed
3528[perl #21469]. This
3529means the following code will no longer crash:
5076a392 3530
e8e35311
FC
3531 for $x (...) {
3532 *x = *y;
3533 }
5076a392
FC
3534
3535=item *
3536
3537Assigning a glob to a PVLV used to convert it to a plain string. Now it
3538works correctly, and a PVLV can hold a glob. This would happen when a
3539nonexistent hash or array element was passed to a subroutine:
3540
3541 sub { $_[0] = *foo }->($hash{key});
3542 # $_[0] would have been the string "*main::foo"
3543
3544It also happened when a glob was assigned to, or returned from, an element
3545of a tied array or hash [perl #36051].
3546
3547=item *
44691e6f 3548
e8e35311 3549When trying to report C<Use of uninitialized value $Foo::BAR>, crashes could
e262cb24
FC
3550occur if the glob holding the global variable in question had been detached
3551from its original stash by, for example, C<delete $::{'Foo::'}>. This has
3552been fixed by disabling the reporting of variable names in those
e8e35311 3553cases.
44691e6f
AB
3554
3555=item *
3556
e8e35311
FC
3557During the restoration of a localised typeglob on scope exit, any
3558destructors called as a result would be able to see the typeglob in an
3559inconsistent state, containing freed entries, which could result in a
3560crash. This would affect code like this:
3561
3562 local *@;