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Note the Attribute::Handlers upgrade 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
fcd5df6d
FR
1235C<Attribute::Handlers> has been upgraded from version 0.87 to 0.89.
1236
1237=item *
1238
3f5a47e4
FR
1239C<autodie> has been upgraded from version 2.06_01 to 2.1001.
1240
1241=item *
1242
578e7c9d
FR
1243C<AutoLoader> has been upgraded from version 5.70 to 5.71.
1244
1245=item *
1246
a13baafd 1247C<B> has been upgraded from version 1.23 to 1.29.
5076a392
FC
1248
1249It no longer crashes when taking apart a C<y///> containing characters
1250outside the octet range or compiled in a C<use utf8> scope.
1251
1252The size of the shared object has been reduced by about 40%, with no
1253reduction in functionality.
1254
1255=item *
1256
4a75fbf5 1257C<B::Concise> has been upgraded from version 0.78 to 0.83.
5076a392
FC
1258
1259B::Concise marks rv2sv, rv2av and rv2hv ops with the new OPpDEREF flag
1260as "DREFed".
1261
1262It no longer produces mangled output with the C<-tree> option
1263[perl #80632].
1264
1265=item *
1266
6bb8c1e3
FR
1267C<B::Debug> has been upgraded from version 1.12 to 1.16.
1268
1269=item *
1270
c67a4e29 1271C<B::Deparse> has been upgraded from version 0.96 to 1.03.
5076a392 1272
1984204c 1273The deparsing of a nextstate op has changed when it has both a
5076a392
FC
1274change of package (relative to the previous nextstate), or a change of
1275C<%^H> or other state, and a label. Previously the label was emitted
cdc10f43 1276first, but now the label is emitted last (5.12.1).
5076a392 1277
5a553547
FC
1278The C<no 5.13.2> or similar form is now correctly handled by B::Deparse
1279(5.12.3).
5076a392
FC
1280
1281B::Deparse now properly handles the code that applies a conditional
1282pattern match against implicit C<$_> as it was fixed in [perl #20444].
1283
1984204c
FC
1284Deparsing of C<our> followed by a variable with funny characters
1285(as permitted under the C<utf8> pragma) has also been fixed [perl #33752].
5076a392
FC
1286
1287=item *
1288
d97c5d3b
FR
1289C<B::Lint> has been upgraded from version 1.11_01 to 1.13.
1290
1291=item *
1292
5aef2c44
FR
1293C<base> has been upgraded from version 2.15 to 2.16.
1294
1295=item *
1296
e539ae69
FR
1297C<bignum> has been upgraded from version 0.23 to 0.26.
1298
1299=item *
1300
c74c1fa8 1301C<Carp> has been upgraded from version 1.15 to 1.20.
5076a392
FC
1302
1303L<Carp> now detects incomplete L<caller()|perlfunc/"caller EXPR"> overrides and
d430b8e7
FC
1304avoids using bogus C<@DB::args>. To provide backtraces,
1305Carp relies on particular behaviour of the C<caller>
1306built-in. Carp now detects if other code has
5076a392 1307overridden this with an incomplete implementation, and modifies its backtrace
d430b8e7
FC
1308accordingly. Previously incomplete overrides would cause incorrect values
1309in backtraces (best case), or obscure fatal errors (worst case).
5076a392
FC
1310
1311This fixes certain cases of C<Bizarre copy of ARRAY> caused by modules
d430b8e7 1312overriding C<caller()> incorrectly (5.12.2).
5076a392 1313
1984204c 1314It now also avoids using regular expressions that cause perl to
5076a392
FC
1315load its Unicode tables, in order to avoid the 'BEGIN not safe after
1316errors' error that will ensue if there has been a syntax error
1317[perl #82854].
1318
1319=item *
1320
9eb7ad55 1321C<CGI> has been upgraded from version 3.48 to 3.52.
5076a392
FC
1322
1323This provides the following security fixes: the MIME boundary in
1984204c
FC
1324multipart_init is now random and the handling of
1325newlines embedded in header values has been improved.
5076a392
FC
1326
1327=item *
1328
5076a392
FC
1329C<Compress::Raw::Bzip2> has been upgraded from version 2.024 to 2.033.
1330
1984204c 1331It has been updated to use bzip2 1.0.6.
5076a392
FC
1332
1333=item *
1334
51090521
FR
1335C<Compress::Raw::Zlib> has been upgraded from version 2.024 to 2.033.
1336
1337=item *
1338
f75b7efc 1339C<CPAN> has been upgraded from version 1.94_56 to 1.9600.
1984204c
FC
1340
1341Major highlights:
5076a392
FC
1342
1343=over 4
1344
1984204c 1345=item * much less configuration dialog hassle
5076a392 1346
1984204c 1347=item * support for META/MYMETA.json
5076a392 1348
1984204c 1349=item * support for local::lib
5076a392 1350
1984204c 1351=item * support for HTTP::Tiny to reduce the dependency on ftp sites
5076a392 1352
1984204c 1353=item * automatic mirror selection
5076a392 1354
1984204c 1355=item * iron out all known bugs in configure_requires
5076a392 1356
1984204c
FC
1357=item * support for distributions compressed with bzip2
1358
1359=item * allow Foo/Bar.pm on the commandline to mean Foo::Bar
1360
1361=back
5076a392
FC
1362
1363=item *
1364
d430b8e7
FC
1365C<CPANPLUS> has been upgraded from version 0.90 to 0.9103.
1366
1367A change to F<cpanp-run-perl>
1368resolves L<RT #55964|http://rt.cpan.org/Public/Bug/Display.html?id=55964>
1369and L<RT #57106|http://rt.cpan.org/Public/Bug/Display.html?id=57106>, both
1370of which related to failures to install distributions that use
1371C<Module::Install::DSL> (5.12.2).
5076a392 1372
1984204c
FC
1373A dependency on Config was not recognised as a
1374core module dependency. This has been fixed.
5076a392 1375
1984204c 1376CPANPLUS now includes support for META.json and MYMETA.json.
5076a392
FC
1377
1378=item *
1379
4467e8f7
FR
1380C<CPANPLUS::Dist::Build> has been upgraded from version 0.46 to 0.54.
1381
1382=item *
1383
5076a392
FC
1384C<Data::Dumper> has been upgraded from version 2.125 to 2.130_02.
1385
4ed2cea4
FC
1386The indentation used to be off when C<$Data::Dumper::Terse> was set. This
1387has been fixed [perl #73604].
1388
1984204c
FC
1389This upgrade also fixes a crash when using custom sort functions that might
1390cause the stack to change [perl #74170].
5076a392
FC
1391
1392C<Dumpxs> no longer crashes with globs returned by C<*$io_ref>
1393[perl #72332].
1394
1395=item *
1396
549d34f5
FR
1397C<DB_File> has been upgraded from version 1.820 to 1.821.
1398
1399=item *
1400
5076a392
FC
1401C<Devel::DProf> has been upgraded from version 20080331.00 to 20110228.00.
1402
1403Merely loading C<Devel::DProf> now no longer triggers profiling to start.
1404C<use Devel::DProf> and C<perl -d:DProf ...> still behave as before and start
1405the profiler.
1406
1407NOTE: C<Devel::DProf> is deprecated and will be removed from a future
1984204c 1408version of Perl. We strongly recommend that you install and use
5076a392
FC
1409L<Devel::NYTProf> instead, as it offers significantly improved
1410profiling and reporting.
1411
1412=item *
1413
66899ca3
FR
1414C<Devel::SelfStubber> has been upgraded from version 1.03 to 1.05.
1415
1416=item *
1417
5076a392
FC
1418C<diagnostics> has been upgraded from version 1.19 to 1.22.
1419
1420It now renders pod links slightly better, and has been taught to find
1421descriptions for messages that share their descriptions with other
1422messages.
1423
1424=item *
1425
1426C<Digest::MD5> has been upgraded from version 2.39 to 2.51.
1427
1428It is now safe to use this module in combination with threads.
1429
1430=item *
1431
1432C<Digest::SHA> has been upgraded from version 5.47 to 5.61.
1433
1434C<shasum> now more closely mimics C<sha1sum>/C<md5sum>.
1435
1436C<Addfile> accepts all POSIX filenames.
1437
1984204c
FC
1438New SHA-512/224 and SHA-512/256 transforms (ref. NIST Draft FIPS 180-4
1439[February 2011])
5076a392
FC
1440
1441=item *
1442
e53cbaa3
FR
1443C<Dumpvalue> has been upgraded from version 1.13 to 1.16.
1444
1445=item *
1446
31e8b85a 1447C<DynaLoader> has been upgraded from version 1.10 to 1.13.
5076a392
FC
1448
1449It fixes a buffer overflow when passed a very long file name.
1450
1451It no longer inherits from AutoLoader; hence it no longer
1452produces weird error messages for unsuccessful method calls on classes that
1453inherit from DynaLoader [perl #84358].
1454
1455=item *
1456
1457C<Encode> has been upgraded from version 2.39 to 2.42.
1458
1459Now, all 66 Unicode non-characters are treated the same way U+FFFF has
1984204c
FC
1460always been treated; in cases when it was disallowed, all 66 are
1461disallowed; in those cases where it warned, all 66 warn.
5076a392
FC
1462
1463=item *
1464
68f90ac3
FR
1465C<Env> has been upgraded from version 1.01 to 1.02.
1466
1467=item *
1468
5076a392
FC
1469C<Errno> has been upgraded from version 1.11 to 1.13.
1470
1471The implementation of C<Errno> has been refactored to use about 55% less memory.
5076a392
FC
1472
1473On some platforms with unusual header files, like Win32/gcc using mingw64
1474headers, some constants which weren't actually error numbers have been exposed
1475by C<Errno>. This has been fixed [perl #77416].
1476
1477=item *
1478
1479C<Exporter> has been upgraded from version 5.64_01 to 5.64_03.
1480
1481Exporter no longer overrides C<$SIG{__WARN__}> [perl #74472]
1482
1483=item *
1484
25fe7f8f
FR
1485C<ExtUtils::CBuilder> has been upgraded from version 0.27 to 0.280202.
1486
1487=item *
1488
2292e71e
FR
1489C<ExtUtils::Command> has been upgraded from version 1.16 to 1.17.
1490
1491=item *
1492
5076a392
FC
1493C<ExtUtils::Constant> has been upgraded from 0.22 to 0.23.
1494
1495The C<AUTOLOAD> helper code generated by C<ExtUtils::Constant::ProxySubs>
1496can now C<croak> for missing constants, or generate a complete C<AUTOLOAD>
1984204c
FC
1497subroutine in XS, allowing simplification of many modules that use it
1498(C<Fcntl>, C<File::Glob>, C<GDBM_File>, C<I18N::Langinfo>, C<POSIX>,
1499C<Socket>).
5076a392
FC
1500
1501C<ExtUtils::Constant::ProxySubs> can now optionally push the names of all
1984204c 1502constants onto the package's C<@EXPORT_OK>.
5076a392
FC
1503
1504=item *
1505
588c5853
FR
1506C<ExtUtils::Install> has been upgraded from version 1.55 to 1.56.
1507
1508=item *
1509
5418ffb3
FR
1510C<ExtUtils::MakeMaker> has been upgraded from version 6.56 to 6.57_05.
1511
1512=item *
1513
f40ab45f
FR
1514C<ExtUtils::Manifest> has been upgraded from version 1.57 to 1.58.
1515
1516=item *
1517
b7064dd7
FR
1518C<ExtUtils::ParseXS> has been upgraded from version 2.21 to 2.2209.
1519
1520=item *
1521
05102622
FR
1522C<File::CheckTree> has been upgraded from version 4.4 to 4.41.
1523
1524=item *
1525
e12786fa 1526C<File::DosGlob> has been upgraded from version 1.01 to 1.04.
5076a392
FC
1527
1528It allows patterns containing literal parentheses (they no longer need to
1984204c
FC
1529be escaped). On Windows, it no longer
1530adds an extra F<./> to the file names
5076a392
FC
1531returned when the pattern is a relative glob with a drive specification,
1532like F<c:*.pl> [perl #71712].
1533
1534=item *
1535
1536C<File::Fetch> has been upgraded from version 0.24 to 0.32.
1537
1538C<HTTP::Lite> is now supported for 'http' scheme.
1539
1540The C<fetch> utility is supported on FreeBSD, NetBSD and
1541Dragonfly BSD for the C<http> and C<ftp> schemes.
1542
1543=item *
1544
23f2cbb1 1545C<File::Find> has been upgraded from version 1.15 to 1.19.
5076a392 1546
1984204c 1547It improves handling of backslashes on Windows, so that paths like
5076a392
FC
1548F<c:\dir\/file> are no longer generated [perl #71710].
1549
1550=item *
1551
d430b8e7
FC
1552C<File::Spec> has been upgraded from version 3.31 to 3.33.
1553
1554Several portability fixes were made in C<File::Spec::VMS>: a colon is now
1555recognized as a delimiter in native filespecs; caret-escaped delimiters are
1556recognized for better handling of extended filespecs; C<catpath()> returns
1557an empty directory rather than the current directory if the input directory
1558name is empty; C<abs2rel()> properly handles Unix-style input (5.12.2).
1559
1560=item *
1561
46ba0657 1562C<File::stat> has been upgraded from 1.02 to 1.05.
5076a392
FC
1563
1564The C<-x> and C<-X> file test operators now work correctly under the root
1565user.
1566
1567=item *
1568
b7edcc3c
FR
1569C<Filter::Simple> has been upgraded from version 0.84 to 0.86.
1570
1571=item *
1572
dc6857fd 1573C<GDBM_File> has been upgraded from 1.10 to 1.14.
5076a392
FC
1574
1575This fixes a memory leak when DBM filters are used.
1576
1577=item *
1578
6e107b45 1579C<Hash::Util> has been upgraded from 0.07 to 0.11.
5076a392 1580
1984204c
FC
1581Hash::Util no longer emits spurious "uninitialized" warnings when
1582recursively locking hashes that have undefined values [perl #74280].
5076a392
FC
1583
1584=item *
1585
eec33fe6
FR
1586C<I18N::Collate> has been upgraded from version 1.01 to 1.02.
1587
1588=item *
1589
ad5f8f47 1590C<I18N::Langinfo> has been upgraded from version 0.03 to 0.08.
5076a392
FC
1591
1592C<langinfo()> now defaults to using C<$_> if there is no argument given, just
5334145a 1593as the documentation has always claimed.
5076a392
FC
1594
1595=item *
1596
c41635f7
FR
1597C<I18N::LangTags> has been upgraded from version 0.35 to 0.35_01.
1598
1599=item *
1600
98a6a4ff
FR
1601C<if> has been upgraded from version 0.05 to 0.0601.
1602
1603=item *
1604
f6ff7fb6
FR
1605C<IO> has been upgraded from version 1.25_02 to 1.25_04.
1606
1607=item *
1608
d13528c5 1609C<IO::Select> has been upgraded from version 1.17 to 1.20.
5076a392
FC
1610
1611It now allows IO::Handle objects (and objects in derived classes) to be
1612removed from an IO::Select set even if the underlying file descriptor is
1613closed or invalid.
1614
1615=item *
1616
d07561d3 1617C<IPC::Cmd> has been upgraded from version 0.54 to 0.70.
5076a392 1618
1984204c
FC
1619Resolves an issue with splitting Win32 command lines. An argument
1620consisting of the single character "0" used to be omitted (CPAN RT #62961).
5076a392
FC
1621
1622=item *
1623
3f16e4eb 1624C<IPC::Open3> has been upgraded from 1.05 to 1.09.
5076a392 1625
4ed2cea4
FC
1626C<open3> now produces an error if the C<exec> call fails, allowing this
1627condition to be distinguished from a child process that exited with a
1628non-zero status [perl #72016].
1629
5076a392
FC
1630The internal C<xclose> routine now knows how to handle file descriptors, as
1631documented, so duplicating STDIN in a child process using its file
1632descriptor now works [perl #76474].
1633
1634=item *
1635
c8b41807
FR
1636C<IPC::SysV> has been upgraded from version 2.01 to 2.03.
1637
1638=item *
1639
ef79f038
FR
1640C<lib> has been upgraded from version 0.62 to 0.63.
1641
1642=item *
1643
5b1884f4 1644C<Locale::Maketext> has been upgraded from version 1.14 to 1.19.
5076a392 1645
1984204c 1646Locale::Maketext now supports external caches.
5076a392 1647
1984204c
FC
1648This upgrade also fixes an infinite loop in
1649C<Locale::Maketext::Guts::_compile()> when
5076a392
FC
1650working with tainted values (CPAN RT #40727).
1651
1984204c 1652C<< ->maketext >> calls will now back up and restore C<$@> so that error
5076a392
FC
1653messages are not suppressed (CPAN RT #34182).
1654
1655=item *
1656
3811bd2b
FR
1657C<Log::Message> has been upgraded from version 0.02 to 0.04.
1658
1659=item *
1660
8eb65377
FR
1661C<Log::Message::Simple> has been upgraded from version 0.06 to 0.08.
1662
1663=item *
1664
5076a392
FC
1665C<Math::BigInt> has been upgraded from version 1.89_01 to 1.994.
1666
1667This fixes, among other things, incorrect results when computing binomial
1668coefficients [perl #77640].
1669
1984204c 1670It also prevents C<sqrt($int)> from crashing under C<use bigrat;>
5076a392
FC
1671[perl #73534].
1672
1673=item *
1674
846c1cec
FR
1675C<Math::BigInt::FastCalc> has been upgraded from version 0.19 to 0.28.
1676
1677=item *
1678
fce4aef3
FR
1679C<Math::BigRat> has been upgraded from version 0.24 to 0.26_02.
1680
1681=item *
1682
12e26027
FR
1683C<Memoize> has been upgraded from version 1.01_03 to 1.02.
1684
1685=item *
1686
5076a392
FC
1687C<MIME::Base64> has been upgraded from 3.08 to 3.13.
1688
1689Includes new functions to calculate the length of encoded and decoded
1690base64 strings.
1691
1692Now provides C<encode_base64url> and C<decode_base64url> functions to process
1693the base64 scheme for "URL applications".
1694
1695=item *
1696
1697C<Module::Build> has been upgraded from version 0.3603 to 0.3800.
1698
1699A notable change is the deprecation of several modules.
1700Module::Build::Version has been deprecated and Module::Build now relies
1701directly upon L<version>. Module::Build::ModuleInfo has been deprecated in
1702favor of a standalone copy of it called L<Module::Metadata>.
1703Module::Build::YAML has been deprecated in favor of L<CPAN::Meta::YAML>.
1704
1705Module::Build now also generates META.json and MYMETA.json files
1706in accordance with version 2 of the CPAN distribution metadata specification,
1707L<CPAN::Meta::Spec>. The older format META.yml and MYMETA.yml files are
1708still generated, as well.
1709
1710=item *
1711
7259fe26 1712C<Module::CoreList> has been upgraded from version 2.29 to 2.47.
5076a392
FC
1713
1714Besides listing the updated core modules of this release, it also stops listing
1984204c 1715the C<Filespec> module. That module never existed in core. The scripts
5076a392 1716generating C<Module::CoreList> confused it with C<VMS::Filespec>, which actually
1984204c 1717is a core module as of perl 5.8.7.
5076a392
FC
1718
1719=item *
1720
193af05b
FR
1721C<Module::Load> has been upgraded from version 0.16 to 0.18.
1722
1723=item *
1724
5b3a054f
FR
1725C<Module::Load::Conditional> has been upgraded from version 0.34 to 0.44.
1726
1727=item *
1728
4f978a3b
FR
1729C<NDBM_File> has been upgraded from version 1.08 to 1.11.
1730
1731This fixes a memory leak when DBM filters are used.
1732
1733=item *
1734
d0aa5c91
FR
1735C<Net::Ping> has been upgraded from version 2.36 to 2.38.
1736
1737=item *
1738
d44b8a8c
FR
1739C<NEXT> has been upgraded from version 0.64 to 0.65.
1740
1741=item *
1742
678d4fd4
FR
1743C<Object::Accessor> has been upgraded from version 0.36 to 0.38.
1744
1745=item *
1746
34188656 1747C<ODBM_File> have been upgraded from version 1.07 to 1.10.
5076a392
FC
1748
1749This fixes a memory leak when DBM filters are used.
1750
1751=item *
1752
77be713d 1753C<overload> has been upgraded from 1.10 to 1.12.
5076a392
FC
1754
1755C<overload::Method> can now handle subroutines that are themselves blessed
1756into overloaded classes [perl #71998].
1757
5076a392
FC
1758The documentation has greatly improved. See L</Documentation> below.
1759
1760=item *
1761
f84c796e
FR
1762C<Params::Check> has been upgraded from version 0.26 to 0.28.
1763
1764=item *
1765
550ee92b
FR
1766C<parent> has been upgraded from version 0.223 to 0.225.
1767
1768=item *
1769
5076a392
FC
1770C<Parse::CPAN::Meta> has been upgraded from version 1.40 to 1.4401.
1771
1984204c 1772The latest Parse::CPAN::Meta can now read YAML and JSON files using
5076a392
FC
1773L<CPAN::Meta::YAML> and L<JSON::PP>, which are now part of the Perl core.
1774
1775=item *
1776
5076a392
FC
1777C<PerlIO::scalar> has been upgraded from 0.07 to 0.11.
1778
1779A C<read> after a C<seek> beyond the end of the string no longer thinks it
1780has data to read [perl #78716].
1781
1782=item *
1783
be3c8498
FR
1784C<Pod::LaTeX> has been upgraded from version 0.58 to 0.59.
1785
1786=item *
1787
fd8a2e89
FR
1788C<Pod::Perldoc> has been upgraded from version 3.15_02 to 3.15_03.
1789
1790=item *
1791
5bcb6583
FR
1792C<Pod::Simple> has been upgraded from version 3.13 to 3.16.
1793
1794=item *
1795
abb8c779 1796C<POSIX> has been upgraded from 1.19 to 1.24.
5076a392
FC
1797
1798It now includes constants for POSIX signal constants.
1799
1800=item *
1801
1984204c 1802C<re> has been upgraded from version 0.11 to 0.17.
5076a392
FC
1803
1804New C<use re "/flags"> pragma
1805
5076a392 1806The C<regmust> function used to crash when called on a regular expression
1984204c 1807belonging to a pluggable engine. Now it croaks instead.
5076a392
FC
1808
1809C<regmust> no longer leaks memory.
1810
1811=item *
1812
1813C<Safe> has been upgraded from version 2.25 to 2.29.
1814
cdc10f43
FC
1815Coderefs returned by C<reval()> and C<rdo()> are now wrapped via
1816C<wrap_code_refs> (5.12.1).
1817
5076a392
FC
1818This fixes a possible infinite loop when looking for coderefs.
1819
cdc10f43 1820It adds several version::vxs::* routines to the default share.
5076a392
FC
1821
1822=item *
1823
5076a392
FC
1824C<SelfLoader> has been upgraded from 1.17 to 1.18.
1825
1826It now works in taint mode [perl #72062].
1827
1828=item *
1829
1830C<sigtrap> has been upgraded from version 1.04 to 1.05.
1831
1832It no longer tries to modify read-only arguments when generating a
1833backtrace [perl #72340].
1834
1835=item *
1836
1984204c 1837C<Socket> has been upgraded from version 1.87 to 1.94.
5076a392 1838
1984204c 1839See L</IPv6 support>, above.
5076a392
FC
1840
1841=item *
1842
1843C<Storable> has been upgraded from version 2.22 to 2.27.
1844
1845Includes performance improvement for overloaded classes.
1846
5076a392 1847This adds support for serialising code references that contain UTF-8 strings
1984204c
FC
1848correctly. The Storable minor version
1849number changed as a result, meaning that
5076a392
FC
1850Storable users who set C<$Storable::accept_future_minor> to a C<FALSE> value
1851will see errors (see L<Storable/FORWARD COMPATIBILITY> for more details).
1852
1853Freezing no longer gets confused if the Perl stack gets reallocated
1854during freezing [perl #80074].
1855
1856=item *
1857
90c6e78f
FR
1858C<Term::ANSIColor> has been upgraded from version 2.02 to 3.00.
1859
1860=item *
1861
d9f2f059
FR
1862C<Term::UI> has been upgraded from version 0.20 to 0.26.
1863
1864=item *
1865
80ebb519
FR
1866C<Test::Harness> has been upgraded from version 3.17 to 3.23.
1867
1868=item *
1869
5076a392
FC
1870C<Test::Simple> has been upgraded from version 0.94 to 0.98.
1871
1872Among many other things, subtests without a C<plan> or C<no_plan> now have an
1873implicit C<done_testing()> added to them.
1874
1875=item *
1876
5076a392
FC
1877C<Thread::Semaphore> has been upgraded from version 2.09 to 2.12.
1878
1984204c
FC
1879It provides two new methods that give more control over the decrementing of
1880semaphores: C<down_nb> and C<down_force>.
5076a392
FC
1881
1882=item *
1883
f0d895e1
FR
1884C<Thread::Queue> has been upgraded from version 2.11 to 2.12.
1885
1886=item *
1887
1a6b954e
FR
1888C<threads> has been upgraded from version 1.75 to 1.83.
1889
1890=item *
1891
55816daa
FR
1892C<threads::shared> has been upgraded from version 1.32 to 1.36.
1893
1894=item *
1895
5076a392
FC
1896C<Tie::Hash> has been upgraded from version 1.03 to 1.04.
1897
1898Calling C<< Tie::Hash-E<gt>TIEHASH() >> used to loop forever. Now it C<croak>s.
1899
1900=item *
1901
ed68b07e
FR
1902C<Tie::RefHash> has been upgraded from version 1.38 to 1.39.
1903
1904=item *
1905
bb3c221a
FR
1906C<Time::HiRes> has been upgraded from version 1.9719 to 1.9721_01.
1907
1908=item *
1909
97fa568b
FR
1910C<Time::Local> has been upgraded from version 1.1901_01 to 1.2000.
1911
1912=item *
1913
a83cb732
FR
1914C<Time::Piece> has been upgraded from version 1.15_01 to 1.20_01.
1915
1916=item *
1917
5076a392
FC
1918C<Unicode::Collate> has been upgraded from version 0.52_01 to 0.73.
1919
1984204c 1920Unicode::Collate has been updated to use Unicode 6.0.0.
5076a392 1921
1984204c
FC
1922Unicode::Collate::Locale now supports a plethora of new locales: ar, be,
1923bg, de__phonebook, hu, hy, kk, mk, nso, om, tn, vi, hr, ig, ja, ko, ru, sq,
1924se, sr, to, uk, zh, zh__big5han, zh__gb2312han, zh__pinyin and zh__stroke.
5076a392
FC
1925
1926The following modules have been added:
1927
1928C<Unicode::Collate::CJK::Big5> for C<zh__big5han> which makes
1929tailoring of CJK Unified Ideographs in the order of CLDR's big5han ordering.
1930
1931C<Unicode::Collate::CJK::GB2312> for C<zh__gb2312han> which makes
1932tailoring of CJK Unified Ideographs in the order of CLDR's gb2312han ordering.
1933
1934C<Unicode::Collate::CJK::JISX0208> which makes tailoring of 6355 kanji
1935(CJK Unified Ideographs) in the JIS X 0208 order.
1936
1937C<Unicode::Collate::CJK::Korean> which makes tailoring of CJK Unified Ideographs
1938in the order of CLDR's Korean ordering.
1939
1940C<Unicode::Collate::CJK::Pinyin> for C<zh__pinyin> which makes
1941tailoring of CJK Unified Ideographs in the order of CLDR's pinyin ordering.
1942
1943C<Unicode::Collate::CJK::Stroke> for C<zh__stroke> which makes
1944tailoring of CJK Unified Ideographs in the order of CLDR's stroke ordering.
1945
5076a392
FC
1946This also sees the switch from using the pure-perl version of this
1947module to the XS version.
1948
1949=item *
1950
ec52b54b
FR
1951C<Unicode::Normalize> has been upgraded from version 1.03 to 1.10.
1952
1953=item *
1954
5076a392
FC
1955C<Unicode::UCD> has been upgraded from version 0.27 to 0.32.
1956
1984204c
FC
1957A new function, C<Unicode::UCD::num()>, has been added. This function
1958returns the numeric value of the string passed it or C<undef> if the string
1959in its entirety has no "safe" numeric value. (For more detail, and for the
1960definition of "safe", see L<Unicode::UCD/num>.)
5076a392 1961
1984204c 1962This upgrade also includes a number of bug fixes:
5076a392
FC
1963
1964=over 4
1965
1966=item charinfo()
1967
1968=over 4
1969
1970=item *
1971
1972It is now updated to Unicode Version 6 with Corrigendum #8, except,
1973as with Perl 5.14, the code point at U+1F514 has no name.
1974
1975=item *
1976
1977The Hangul syllable code points have the correct names, and their
1978decompositions are always output without requiring L<Lingua::KO::Hangul::Util>
1979to be installed.
1980
1981=item *
1982
54c7bb16
FC
1983The CJK (Chinese-Japanese-Korean) code points U+2A700 to U+2B734
1984and U+2B740 to U+2B81D are now properly handled.
5076a392
FC
1985
1986=item *
1987
1988The numeric values are now output for those CJK code points that have them.
1989
1990=item *
1991
1992The names that are output for code points with multiple aliases are now the
1993corrected ones.
1994
1995=back
1996
1997=item charscript()
1998
1999This now correctly returns "Unknown" instead of C<undef> for the script
2000of a code point that hasn't been assigned another one.
2001
2002=item charblock()
2003
2004This now correctly returns "No_Block" instead of C<undef> for the block
2005of a code point that hasn't been assigned to another one.
2006
2007=back
2008
5076a392
FC
2009=item *
2010
2011C<version> has been upgraded from 0.82 to 0.88.
2012
1984204c 2013Due to a bug, now fixed, the C<is_strict> and C<is_lax> functions did not
cdc10f43 2014work when exported (5.12.1).
5076a392
FC
2015
2016=item *
2017
3e625598 2018C<warnings> has been upgraded from version 1.09 to 1.12.
5076a392
FC
2019
2020Calling C<use warnings> without arguments is now significantly more efficient.
2021
4f978a3b
FR
2022=item *
2023
2024C<warnings::register> have been upgraded from version 1.01 to 1.02.
2025
5076a392
FC
2026It is now possible to register warning categories other than the names of
2027packages using C<warnings::register>. See L<perllexwarn> for more information.
2028
2029=item *
2030
62e270c2
FR
2031C<XSLoader> has been upgraded from version 0.10 to 0.13.
2032
2033=item *
2034
5076a392
FC
2035C<VMS::DCLsym> has been upgraded from version 1.03 to 1.05.
2036
2037Two bugs have been fixed [perl #84086]:
2038
2039The symbol table name was lost when tying a hash, due to a thinko in
2040C<TIEHASH>. The result was that all tied hashes interacted with the
2041local symbol table.
2042
2043Unless a symbol table name had been explicitly specified in the call
2044to the constructor, querying the special key ':LOCAL' failed to
2045identify objects connected to the local symbol table.
2046
2047=item *
2048
2049C<Win32> has been upgraded from version 0.39 to 0.44.
2050
1984204c
FC
2051This release has several new functions: C<Win32::GetSystemMetrics>,
2052C<Win32::GetProductInfo>, C<Win32::GetOSDisplayName>.
5076a392 2053
1984204c
FC
2054The names returned by C<Win32::GetOSName> and C<Win32::GetOSDisplayName>
2055have been corrected.
5076a392 2056
5076a392
FC
2057=back
2058
5076a392
FC
2059=head2 Removed Modules and Pragmata
2060
2061The following modules have been removed from the core distribution, and if
2062needed should be installed from CPAN instead.
2063
2064=over
2065
4f978a3b
FR
2066=item *
2067
2068C<Class::ISA> has been removed from the Perl core. Prior version was 0.36.
5076a392 2069
4f978a3b
FR
2070=item *
2071
2072C<Pod::Plainer> has been removed from the Perl core. Prior version was 1.02.
2073
2074=item *
5076a392 2075
4f978a3b 2076C<Switch> has been removed from the Perl core. Prior version was 2.16.
5076a392
FC
2077
2078=back
2079
2080The removal of C<Shell> has been deferred until after 5.14, as the
2081implementation of C<Shell> shipped with 5.12.0 did not correctly issue the
2082warning that it was to be removed from core.
2083
2084=head1 Documentation
2085
5076a392
FC
2086=head2 New Documentation
2087
41e29def 2088=head3 L<perlgpl>
5076a392
FC
2089
2090L<perlgpl> has been updated to contain GPL version 1, as is included in the
cdc10f43 2091F<README> distributed with perl (5.12.1).
5076a392 2092
41e29def 2093=head3 Perl 5.12.x delta files
5076a392 2094
41e29def
FC
2095The perldelta files for Perl 5.12.1 to 5.12.3 have been added from the
2096maintenance branch: L<perl5121delta>, L<perl5122delta>, L<perl5123delta>.
5076a392
FC
2097
2098=head3 L<perlpodstyle>
2099
2100New style guide for POD documentation,
2101split mostly from the NOTES section of the pod2man man page.
2102
41e29def
FC
2103=head3 L<perlsource>, L<perlinterp>, L<perlhacktut>, and L<perlhacktips>
2104
2105See L</L<perlhack> and perlrepository revamp>, below.
5076a392
FC
2106
2107=head2 Changes to Existing Documentation
2108
41e29def 2109=head3 L<perlmodlib> is now complete
4ed2cea4
FC
2110
2111The perlmodlib page that came with Perl 5.12.0 was missing a lot of
2112modules, due to a bug in the script that generates the list. This has been
cdc10f43 2113fixed [perl #74332] (5.12.1).
4ed2cea4 2114
41e29def 2115=head3 Replace wrong tr/// table in L<perlebcdic>
5076a392 2116
41e29def 2117L<perlebcdic> contains a helpful table to use in tr/// to convert
5076a392
FC
2118between EBCDIC and Latin1/ASCII. Unfortunately, the table was the
2119inverse of the one it describes, though the code that used the table
2120worked correctly for the specific example given.
2121
2122The table has been changed to its inverse, and the sample code changed
2123to correspond, as this is easier for the person trying to follow the
2124instructions since deriving the old table is somewhat more complicated.
2125
2126The table has also been changed to hex from octal, as that is more the norm
2127these days, and the recipes in the pod altered to print out leading
41e29def 2128zeros to make all the values the same length.
5076a392 2129
41e29def 2130=head3 Tricks for user-defined casing
5076a392 2131
41e29def
FC
2132L<perlunicode> now contains an explanation of how to override, mangle
2133and otherwise tweak the way perl handles upper-, lower- and other-case
2134conversions on Unicode data, and how to provide scoped changes to alter
2135one's own code's behaviour without stomping on anybody else.
5076a392
FC
2136
2137=head3 INSTALL explicitly states the requirement for C89
2138
d430b8e7
FC
2139This was already true but it's now Officially Stated For The Record
2140(5.12.2).
5076a392 2141
41e29def 2142=head3 Explanation of C<\xI<HH>> and C<\oI<OOO>> escapes
5076a392 2143
41e29def
FC
2144L<perlop> has been updated with more detailed explanation of these two
2145character escapes.
5076a392 2146
41e29def 2147=head3 C<-0I<NNN>> switch
5076a392 2148
41e29def 2149In L<perlrun>, the behavior of the C<-0NNN> switch for C<-0400> or higher
d430b8e7 2150has been clarified (5.12.2).
5076a392 2151
cdc10f43
FC
2152=head3 Maintenance policy
2153
2154L<perlpolicy> now contains the policy on what patches are acceptable for
2155maintenance branches (5.12.1).
2156
41e29def 2157=head3 Deprecation policy
5076a392 2158
41e29def 2159L<perlpolicy> now contains the policy on compatibility and deprecation
d430b8e7 2160along with definitions of terms like "deprecation" (5.12.2).
5076a392 2161
41e29def 2162=head3 New descriptions in L<perldiag>
5076a392
FC
2163
2164The following existing diagnostics are now documented:
2165
2166=over 4
2167
2168=item *
2169
2170L<Ambiguous use of %c resolved as operator %c|perldiag/"Ambiguous use of %c resolved as operator %c">
2171
2172=item *
2173
2174L<Ambiguous use of %c{%s} resolved to %c%s|perldiag/"Ambiguous use of %c{%s} resolved to %c%s">
2175
2176=item *
2177
2178L<Ambiguous use of %c{%s%s} resolved to %c%s%s|perldiag/"Ambiguous use of %c{%s%s} resolved to %c%s%s">
2179
2180=item *
2181
2182L<Ambiguous use of -%s resolved as -&%s()|perldiag/"Ambiguous use of -%s resolved as -&%s()">
2183
2184=item *
2185
2186L<Invalid strict version format (%s)|perldiag/"Invalid strict version format (%s)">
2187
2188=item *
2189
2190L<Invalid version format (%s)|perldiag/"Invalid version format (%s)">
2191
2192=item *
2193
2194L<Invalid version object|perldiag/"Invalid version object">
2195
2196=back
2197
5076a392
FC
2198=head3 L<perlbook>
2199
41e29def 2200L<perlbook> has been expanded to cover many more popular books.
5076a392 2201
41e29def 2202=head3 C<SvTRUE> macro
5076a392 2203
41e29def
FC
2204The documentation for the C<SvTRUE> macro in
2205L<perlapi> was simply wrong in stating that
5076a392
FC
2206get-magic is not processed. It has been corrected.
2207
41e29def 2208=head3 L<perlvar> revamp
5076a392 2209
41e29def 2210L<perlvar> reorders the variables and groups them by topic. Each variable
5076a392 2211introduced after Perl 5.000 notes the first version in which it is
41e29def 2212available. L<perlvar> also has a new section for deprecated variables to
5076a392
FC
2213note when they were removed.
2214
41e29def 2215=head3 Array and hash slices in scalar context
5076a392 2216
41e29def 2217These are now documented in L<perldata>.
5076a392 2218
41e29def 2219=head3 C<use locale> and formats
5076a392
FC
2220
2221L<perlform> and L<perllocale> have been corrected to state that
2222C<use locale> affects formats.
2223
5076a392
FC
2224=head3 L<overload>
2225
5076a392
FC
2226L<overload>'s documentation has practically undergone a rewrite. It
2227is now much more straightforward and clear.
2228
41e29def 2229=head3 L<perlhack> and perlrepository revamp
5076a392
FC
2230
2231The L<perlhack> and perlrepository documents have been heavily edited and
2232split up into several new documents.
2233
2234The L<perlhack> document is now much shorter, and focuses on the Perl 5
2235development process and submitting patches to Perl. The technical content has
2236been moved to several new documents, L<perlsource>, L<perlinterp>,
2237L<perlhacktut>, and L<perlhacktips>. This technical content has only been
2238lightly edited.
2239
2240The perlrepository document has been renamed to L<perlgit>. This new document
2241is just a how-to on using git with the Perl source code. Any other content
2242that used to be in perlrepository has been moved to perlhack.
2243
41e29def 2244=head3 Time::Piece examples
5076a392
FC
2245
2246Examples in L<perlfaq4> have been updated to show the use of
41e29def 2247L<Time::Piece>.
5076a392
FC
2248
2249=head1 Diagnostics
2250
2251The following additions or changes have been made to diagnostic output,
2252including warnings and fatal error messages. For the complete list of
2253diagnostic messages, see L<perldiag>.
2254
2255=head2 New Diagnostics
2256
a593b319
FC
2257=head3 New Errors
2258
5076a392
FC
2259=over
2260
a593b319 2261=item Closure prototype called
5076a392 2262
a593b319
FC
2263This error occurs when a subroutine reference passed to an attribute
2264handler is called, if the subroutine is a closure [perl #68560].
5076a392 2265
a593b319 2266=item Insecure user-defined property %s
5076a392 2267
a593b319
FC
2268Perl detected tainted data when trying to compile a regular
2269expression that contains a call to a user-defined character property
2270function, i.e. C<\p{IsFoo}> or C<\p{InFoo}>.
2271See L<perlunicode/User-Defined Character Properties> and L<perlsec>.
5076a392 2272
a593b319 2273=item panic: gp_free failed to free glob pointer - something is repeatedly re-creating entries
5076a392 2274
a593b319
FC
2275This new error is triggered if a destructor called on an object in a
2276typeglob that is being freed creates a new typeglob entry containing an
2277object with a destructor that creates a new entry containing an object....
5076a392 2278
a593b319 2279=item Parsing code internal error (%s)
5076a392 2280
a593b319
FC
2281This new fatal error is produced when parsing
2282code supplied by an extension violates the
2283parser's API in a detectable way.
5076a392 2284
a593b319 2285=item refcnt: fd %d%s
5076a392 2286
a593b319
FC
2287This new error only occurs if a internal consistency check fails when a
2288pipe is about to be closed.
5076a392 2289
a593b319 2290=item Regexp modifier "/%c" may not appear twice
5076a392 2291
a593b319
FC
2292The regular expression pattern has one of the
2293mutually exclusive modifiers repeated.
5076a392 2294
a593b319 2295=item Regexp modifiers "/%c" and "/%c" are mutually exclusive
5076a392 2296
a593b319
FC
2297The regular expression pattern has more than one of the mutually
2298exclusive modifiers.
5076a392 2299
a593b319 2300=item Using !~ with %s doesn't make sense
5076a392 2301
a593b319 2302This error occurs when C<!~> is used with C<s///r> or C<y///r>.
5076a392 2303
a593b319 2304=back
5076a392 2305
a593b319 2306=head3 New Warnings
5076a392 2307
a593b319 2308=over
5076a392 2309
a593b319 2310=item "\b{" is deprecated; use "\b\{" instead
5076a392 2311
a593b319 2312=item "\B{" is deprecated; use "\B\{" instead
5076a392 2313
a593b319
FC
2314Use of an unescaped "{" immediately following a C<\b> or C<\B> is now
2315deprecated so as to reserve its use for Perl itself in a future release.
5076a392 2316
a593b319 2317=item Operation "%s" returns its argument for ...
5076a392 2318
a593b319
FC
2319Performing an operation requiring Unicode semantics (such as case-folding)
2320on a Unicode surrogate or a non-Unicode character now triggers a warning:
2321'Operation "%s" returns its argument for ...'.
5076a392 2322
a593b319
FC
2323=item Use of qw(...) as parentheses is deprecated
2324
2325See L</"Use of qw(...) as parentheses">, above, for details.
5076a392
FC
2326
2327=back
2328
2329=head2 Changes to Existing Diagnostics
2330
2331=over 4
2332
2333=item *
2334
4ed2cea4
FC
2335The "Variable $foo is not imported" warning that precedes a
2336C<strict 'vars'> error has now been assigned the "misc" category, so that
2337C<no warnings> will suppress it [perl #73712].
2338
2339=item *
2340
5076a392
FC
2341C<warn> and C<die> now produce 'Wide character' warnings when fed a
2342character outside the byte range if STDERR is a byte-sized handle.
2343
2344=item *
2345
2346The 'Layer does not match this perl' error message has been replaced with
a593b319 2347these more helpful messages [perl #73754]:
5076a392
FC
2348
2349=over 4
2350
2351=item *
2352
2353PerlIO layer function table size (%d) does not match size expected by this
2354perl (%d)
2355
2356=item *
2357
2358PerlIO layer instance size (%d) does not match size expected by this perl
2359(%d)
2360
2361=back
2362
5076a392
FC
2363=item *
2364
2365The "Found = in conditional" warning that is emitted when a constant is
2366assigned to a variable in a condition is now withheld if the constant is
2367actually a subroutine or one generated by C<use constant>, since the value
2368of the constant may not be known at the time the program is written
2369[perl #77762].
2370
2371=item *
2372
2373Previously, if none of the C<gethostbyaddr>, C<gethostbyname> and
2374C<gethostent> functions were implemented on a given platform, they would
2375all die with the message 'Unsupported socket function "gethostent" called',
2376with analogous messages for C<getnet*> and C<getserv*>. This has been
2377corrected.
2378
2379=item *
2380
a593b319
FC
2381The warning message about unrecognized regular expression escapes passed
2382through has been changed to include any literal '{' following the
2383two-character escape. E.g., "\q{" is now emitted instead of "\q".
5076a392
FC
2384
2385=back
2386
2387=head1 Utility Changes
2388
0b88cc74 2389=head3 L<perlbug>
5076a392
FC
2390
2391=over 4
2392
2393=item *
2394
0b88cc74
FC
2395L<perlbug> now looks in the EMAIL environment variable for a return address
2396if the REPLY-TO and REPLYTO variables are empty.
5076a392
FC
2397
2398=item *
2399
0b88cc74
FC
2400L<perlbug> did not previously generate a From: header, potentially
2401resulting in dropped mail. Now it does include that header.
5076a392
FC
2402
2403=item *
2404
0b88cc74 2405The user's address is now used as the return-path.
4ed2cea4 2406
0b88cc74
FC
2407Many systems these days don't have a valid Internet domain name and
2408perlbug@perl.org does not accept email with a return-path that does
2409not resolve. So the user's address is now passed to sendmail so it's
2410less likely to get stuck in a mail queue somewhere [perl #82996].
5076a392 2411
2c389f6c
FC
2412=item *
2413
d430b8e7
FC
2414L<perlbug> now always gives the reporter a chance to change the email
2415address it guesses for them (5.12.2).
2416
2417=item *
2418
2419L<perlbug> should no longer warn about uninitialized values when using the C<-d>
2420and C<-v> options (5.12.2).
2c389f6c 2421
5076a392
FC
2422=back
2423
0b88cc74 2424=head3 L<perl5db.pl>
5076a392 2425
0b88cc74 2426=over
5076a392
FC
2427
2428=item *
2429
0b88cc74
FC
2430The remote terminal works after forking and spawns new sessions - one
2431for each forked process.
5076a392
FC
2432
2433=back
2434
0b88cc74 2435=head3 L<ptargrep>
5076a392
FC
2436
2437=over 4
2438
2439=item *
2440
0b88cc74
FC
2441L<ptargrep> is a new utility to apply pattern matching to the contents of
2442files in a tar archive. It comes with C<Archive::Tar>.
5076a392
FC
2443
2444=back
2445
2446=head1 Configuration and Compilation
2447
61752d82
FC
2448See also L</"Naming fixes in Policy_sh.SH may invalidate Policy.sh">,
2449above.
2450
5076a392
FC
2451=over 4
2452
2453=item *
2454
87595b22
FC
2455CCINCDIR and CCLIBDIR for the mingw64
2456cross-compiler are now correctly under
5076a392
FC
2457$(CCHOME)\mingw\include and \lib rather than immediately below $(CCHOME).
2458
5076a392
FC
2459This means the 'incpath', 'libpth', 'ldflags', 'lddlflags' and
2460'ldflags_nolargefiles' values in Config.pm and Config_heavy.pl are now
87595b22 2461set correctly.
5076a392
FC
2462
2463=item *
2464
87595b22
FC
2465'make test.valgrind' has been adjusted to account for cpan/dist/ext
2466separation.
5076a392
FC
2467
2468=item *
2469
2470On compilers that support it, C<-Wwrite-strings> is now added to cflags by
2471default.
2472
2473=item *
2474
2475The C<Encode> module can now (once again) be included in a static Perl
2476build. The special-case handling for this situation got broken in Perl
24775.11.0, and has now been repaired.
2478
1e463951
FC
2479=item *
2480
2481The previous default size of a PerlIO buffer (4096 bytes) has been increased
2482to the larger of 8192 bytes and your local BUFSIZ. Benchmarks show that doubling
2483this decade-old default increases read and write performance in the neighborhood
2484of 25% to 50% when using the default layers of perlio on top of unix. To choose
2485a non-default size, such as to get back the old value or to obtain an even
2486larger value, configure with:
2487
2488 ./Configure -Accflags=-DPERLIOBUF_DEFAULT_BUFSIZ=N
2489
2490where N is the desired size in bytes; it should probably be a multiple of
2491your page size.
2492
d430b8e7
FC
2493=item *
2494
2495An "incompatible operand types" error in ternary expressions when building
2496with C<clang> has been fixed (5.12.2).
2497
2498=item *
2499
2500Perl now skips setuid C<File::Copy> tests on partitions it detects to be mounted
2501as C<nosuid> (5.12.2).
2502
5076a392
FC
2503=back
2504
5076a392
FC
2505=head1 Platform Support
2506
5076a392
FC
2507=head2 New Platforms
2508
5076a392
FC
2509=over 4
2510
2511=item AIX
2512
cdc10f43 2513Perl now builds on AIX 4.2 (5.12.1).
5076a392
FC
2514
2515=back
2516
2517=head2 Discontinued Platforms
2518
2519=over 4
2520
5076a392
FC
2521=item Apollo DomainOS
2522
2523The last vestiges of support for this platform have been excised from the
2524Perl distribution. It was officially discontinued in version 5.12.0. It had
2525not worked for years before that.
2526
2527=item MacOS Classic
2528
2529The last vestiges of support for this platform have been excised from the
2530Perl distribution. It was officially discontinued in an earlier version.
2531
2532=back
2533
2534=head2 Platform-Specific Notes
2535
d430b8e7
FC
2536=head3 AIX
2537
2538=over
2539
2540=item *
2541
2542F<README.aix> has been updated with information about the XL C/C++ V11 compiler
2543suite (5.12.2).
2544
2545=back
2546
2547=head3 ARM
2548
2549=over
2550
2551=item *
2552
2553The C<d_u32align> configuration probe on ARM has been fixed (5.12.2).
2554
2555=back
2556
554003a2 2557=head3 Cygwin
5076a392
FC
2558
2559=over 4
2560
2561=item *
2562
554003a2 2563MakeMaker has been updated to build man pages on cygwin.
5076a392
FC
2564
2565=item *
2566
554003a2
FC
2567Improved rebase behaviour
2568
2569If a dll is updated on cygwin the old imagebase address is reused.
2570This solves most rebase errors, especially when updating on core dll's.
2571See L<http://www.tishler.net/jason/software/rebase/rebase-2.4.2.README> for more information.
5076a392
FC
2572
2573=item *
2574
554003a2 2575Support for the standard cygwin dll prefix, which is e.g. needed for FFI's
5076a392
FC
2576
2577=item *
2578
554003a2 2579Updated build hints file
5076a392
FC
2580
2581=back
2582
cdc10f43
FC
2583=head3 FreeBSD 7
2584
2585=over
2586
2587=item *
2588
2589FreeBSD 7 no longer contains F</usr/bin/objformat>. At build time,
2590Perl now skips the F<objformat> check for versions 7 and higher and
2591assumes ELF (5.12.1).
2592
2593=back
2594
2595=head3 HP-UX
2596
2597=over
2598
2599=item *
2600
2601Perl now allows -Duse64bitint without promoting to use64bitall on HP-UX
2602(5.12.1).
2603
2604=back
2605
554003a2 2606=head3 IRIX
5076a392
FC
2607
2608Conversion of strings to floating-point numbers is now more accurate on
2609IRIX systems [perl #32380].
2610
554003a2 2611=head3 Mac OS X
5076a392
FC
2612
2613Early versions of Mac OS X (Darwin) had buggy implementations of the
2614C<setregid>, C<setreuid>, C<setrgid> and C<setruid> functions, so perl
2615would pretend they did not exist.
2616
2617These functions are now recognised on Mac OS 10.5 (Leopard; Darwin 9) and
2618higher, as they have been fixed [perl #72990].
2619
554003a2 2620=head3 MirBSD
5076a392 2621
554003a2
FC
2622Previously if you built perl with a shared libperl.so on MirBSD (the
2623default config), it would work up to the installation; however, once
2624installed, it would be unable to find libperl. So path handling is now
2625treated as in the other BSD dialects.
5076a392 2626
554003a2 2627=head3 NetBSD
5076a392 2628
554003a2
FC
2629The NetBSD hints file has been changed to make the system's malloc the
2630default.
5076a392 2631
554003a2 2632=head3 Recent OpenBSDs now use perl's malloc
5076a392 2633
554003a2
FC
2634OpenBSD E<gt> 3.7 has a new malloc implementation which is mmap-based
2635and as such can release memory back to the OS; however, perl's use of
2636this malloc causes a substantial slowdown so we now default to using
2637perl's malloc instead [perl #75742].
5076a392 2638
554003a2 2639=head3 OpenVOS
5076a392 2640
554003a2 2641perl now builds again with OpenVOS (formerly known as Stratus VOS)
5a553547 2642[perl #78132] (5.12.3).
5076a392 2643
554003a2 2644=head3 Solaris
5076a392 2645
554003a2 2646DTrace is now supported on Solaris. There used to be build failures, but
5a553547 2647these have been fixed [perl #73630] (5.12.3).
5076a392 2648
554003a2 2649=head3 VMS
5076a392
FC
2650
2651=over
2652
2653=item *
2654
cdc10f43
FC
2655It's now possible to build extensions on older (pre 7.3-2) VMS systems.
2656
2657DCL symbol length was limited to 1K up until about seven years or
2658so ago, but there was no particularly deep reason to prevent those
2659older systems from configuring and building Perl (5.12.1).
2660
2661=item *
2662
2663We fixed the previously-broken C<-Uuseperlio> build on VMS.
2664
2665We were checking a variable that doesn't exist in the non-default
2666case of disabling perlio. Now we only look at it when it exists (5.12.1).
2667
2668=item *
2669
2670We fixed the -Uuseperlio command-line option in configure.com.
2671
2672Formerly it only worked if you went through all the questions
2673interactively and explicitly answered no (5.12.1).
2674
2675=item *
2676
554003a2 2677C<PerlIOUnix_open> now honours the default permissions on VMS.
5076a392 2678
554003a2
FC
2679When C<perlio> became the default and C<unixio> became the default bottom layer,
2680the most common path for creating files from Perl became C<PerlIOUnix_open>,
2681which has always explicitly used C<0666> as the permission mask.
5076a392 2682
554003a2
FC
2683To avoid this, C<0777> is now passed as the permissions to C<open()>. In the
2684VMS CRTL, C<0777> has a special meaning over and above intersecting with the
2685current umask; specifically, it allows Unix syscalls to preserve native default
5a553547
FC
2686permissions (5.12.3).
2687
2688=item *
2689
2690Spurious record boundaries are no longer
2691introduced by the PerlIO layer during output (5.12.3).
5076a392
FC
2692
2693=item *
2694
554003a2
FC
2695The shortening of symbols longer than 31 characters in the C sources is
2696now done by the compiler rather than by xsubpp (which could only do so
2697for generated symbols in XS code).
5076a392
FC
2698
2699=item *
2700
554003a2
FC
2701Record-oriented files (record format variable or variable with fixed control)
2702opened for write by the perlio layer will now be line-buffered to prevent the
2703introduction of spurious line breaks whenever the perlio buffer fills up.
5076a392 2704
d430b8e7
FC
2705=item *
2706
2707F<git_version.h> is now installed on VMS. This was an oversight in v5.12.0 which
2708caused some extensions to fail to build (5.12.2).
2709
2710=item *
2711
2712Several memory leaks in L<stat()|perlfunc/"stat FILEHANDLE"> have been fixed (5.12.2).
2713
2714=item *
2715
2716A memory leak in C<Perl_rename()> due to a double allocation has been
2717fixed (5.12.2).
2718
2719=item *
2720
2721A memory leak in C<vms_fid_to_name()> (used by C<realpath()> and
2722C<realname()>) has been fixed (5.12.2).
2723
5076a392
FC
2724=back
2725
554003a2 2726=head3 Windows
5076a392 2727
5a1f7719
FC
2728See also L</"fork() emulation will not wait for signalled children"> and
2729L</"Perl source code is read in text mode on Windows">, above.
2730
5076a392
FC
2731=over 4
2732
2733=item *
2734
554003a2 2735Fixed build process for SDK2003SP1 compilers.
5076a392 2736
554003a2 2737=item *
5076a392 2738
01b1a9e4
FC
2739Compilation with Visual Studio 2010 is now supported.
2740
2741=item *
2742
554003a2
FC
2743When using old 32-bit compilers, the define C<_USE_32BIT_TIME_T> will now
2744be set in C<$Config{ccflags}>. This improves portability when compiling
2745XS extensions using new compilers, but for a perl compiled with old 32-bit
2746compilers.
5076a392
FC
2747
2748=item *
2749
554003a2
FC
2750C<$Config{gccversion}> is now set correctly when perl is built using the
2751mingw64 compiler from L<http://mingw64.org> [perl #73754].
5076a392 2752
554003a2
FC
2753=item *
2754
d430b8e7
FC
2755When building Perl with the mingw64 x64 cross-compiler C<incpath>,
2756C<libpth>, C<ldflags>, C<lddlflags> and C<ldflags_nolargefiles> values
2757in F<Config.pm> and F<Config_heavy.pl> were not previously being set
2758correctly because, with that compiler, the include and lib directories
2759are not immediately below C<$(CCHOME)> (5.12.2).
2760
2761=item *
2762
554003a2
FC
2763The build process proceeds more smoothly with mingw and dmake when
2764F<C:\MSYS\bin> is in the PATH, due to a C<Cwd> fix.
5076a392
FC
2765
2766=item *
2767
554003a2
FC
2768Support for building with Visual C++ 2010 is now underway, but is not yet
2769complete. See F<README.win32> or L<perlwin32> for more details.
5076a392 2770
554003a2
FC
2771=item *
2772
2773The option to use an externally-supplied C<crypt()>, or to build with no
2774C<crypt()> at all, has been removed. Perl supplies its own C<crypt()>
2775implementation for Windows, and the political situation that required
2776this part of the distribution to sometimes be omitted is long gone.
5076a392
FC
2777
2778=back
2779
2780=head1 Internal Changes
2781
1e463951 2782=head2 New APIs
5076a392 2783
1e463951 2784=head3 CLONE_PARAMS structure added to ease correct thread creation
5076a392 2785
1e463951
FC
2786Modules that create threads should now create C<CLONE_PARAMS> structures
2787by calling the new function C<Perl_clone_params_new()>, and free them with
2788C<Perl_clone_params_del()>. This will ensure compatibility with any future
2789changes to the internals of the C<CLONE_PARAMS> structure layout, and that
2790it is correctly allocated and initialised.
5076a392 2791
1e463951 2792=head3 New parsing functions
5076a392 2793
1e463951
FC
2794Several functions have been added for parsing statements or multiple
2795statements:
5076a392 2796
1e463951 2797=over
5076a392
FC
2798
2799=item *
2800
1e463951 2801C<parse_fullstmt> parses a complete Perl statement.
5076a392
FC
2802
2803=item *
2804
1e463951
FC
2805C<parse_stmtseq> parses a sequence of statements, up
2806to closing brace or EOF.
5076a392
FC
2807
2808=item *
2809
1e463951 2810C<parse_block> parses a block [perl #78222].
5076a392
FC
2811
2812=item *
2813
1e463951
FC
2814C<parse_barestmt> parses a statement
2815without a label.
5076a392
FC
2816
2817=item *
2818
1e463951 2819C<parse_label> parses a statement label, separate from statements.
5076a392 2820
1e463951 2821=back
5076a392 2822
1e463951
FC
2823The
2824L<C<parse_fullexpr()>|perlapi/parse_fullexpr>,
2825L<C<parse_listexpr()>|perlapi/parse_listexpr>,
2826L<C<parse_termexpr()>|perlapi/parse_termexpr>, and
2827L<C<parse_arithexpr()>|perlapi/parse_arithexpr>
2828functions have been added to the API. They perform
2829recursive-descent parsing of expressions at various precedence levels.
2830They are expected to be used by syntax plugins.
5076a392 2831
1e463951 2832See L<perlapi> for details.
5076a392 2833
1e463951 2834=head3 Hints hash API
5076a392 2835
1e463951
FC
2836A new C API for introspecting the hinthash C<%^H> at runtime has been
2837added. See C<cop_hints_2hv>, C<cop_hints_fetchpvn>, C<cop_hints_fetchpvs>,
2838C<cop_hints_fetchsv>, and C<hv_copy_hints_hv> in L<perlapi> for details.
5076a392 2839
1e463951
FC
2840A new, experimental API has been added for accessing the internal
2841structure that Perl uses for C<%^H>. See the functions beginning with
2842C<cophh_> in L<perlapi>.
5076a392 2843
1e463951 2844=head3 C interface to C<caller()>
5076a392 2845
1e463951
FC
2846The C<caller_cx> function has been added as an XSUB-writer's equivalent of
2847C<caller()>. See L<perlapi> for details.
5076a392 2848
1e463951 2849=head3 Custom per-subroutine check hooks
5076a392 2850
1e463951
FC
2851XS code in an extension module can now annotate a subroutine (whether
2852implemented in XS or in Perl) so that nominated XS code will be called
2853at compile time (specifically as part of op checking) to change the op
2854tree of that subroutine. The compile-time check function (supplied by
2855the extension module) can implement argument processing that can't be
2856expressed as a prototype, generate customised compile-time warnings,
2857perform constant folding for a pure function, inline a subroutine
2858consisting of sufficiently simple ops, replace the whole call with a
2859custom op, and so on. This was previously all possible by hooking the
2860C<entersub> op checker, but the new mechanism makes it easy to tie the
2861hook to a specific subroutine. See L<perlapi/cv_set_call_checker>.
5076a392 2862
1e463951
FC
2863To help in writing custom check hooks, several subtasks within standard
2864C<entersub> op checking have been separated out and exposed in the API.
5076a392 2865
1e463951 2866=head3 Improved support for custom OPs
5076a392 2867
1e463951
FC
2868Custom ops can now be registered with the new C<custom_op_register> C
2869function and the C<XOP> structure. This will make it easier to add new
2870properties of custom ops in the future. Two new properties have been added
2871already, C<xop_class> and C<xop_peep>.
5076a392 2872
1e463951
FC
2873C<xop_class> is one of the OA_*OP constants, and allows L<B> and other
2874introspection mechanisms to work with custom ops
2875that aren't BASEOPs. C<xop_peep> is a pointer to
2876a function that will be called for ops of this
2877type from C<Perl_rpeep>.
5076a392 2878
1e463951
FC
2879See L<perlguts/Custom Operators> and L<perlapi/Custom Operators> for more
2880detail.
5076a392 2881
1e463951
FC
2882The old C<PL_custom_op_names>/C<PL_custom_op_descs> interface is still
2883supported but discouraged.
5076a392 2884
1e463951 2885=head3 Scope hooks
5076a392 2886
1e463951
FC
2887It is now possible for XS code to hook into Perl's lexical scope
2888mechanism at compile time, using the new C<Perl_blockhook_register>
2889function. See L<perlguts/"Compile-time scope hooks">.
5076a392 2890
1e463951 2891=head3 The recursive part of the peephole optimizer is now hookable
5076a392
FC
2892
2893In addition to C<PL_peepp>, for hooking into the toplevel peephole optimizer, a
2894C<PL_rpeepp> is now available to hook into the optimizer recursing into
2895side-chains of the optree.
2896
1e463951 2897=head3 New non-magical variants of existing functions
5076a392 2898
1e463951
FC
2899The following functions/macros have been added to the API. The C<*_nomg>
2900macros are equivalent to their non-_nomg variants, except that they ignore
2901get-magic. Those ending in C<_flags> allow one to specify whether
2902get-magic is processed.
5076a392 2903
1e463951
FC
2904 sv_2bool_flags
2905 SvTRUE_nomg
2906 sv_2nv_flags
2907 SvNV_nomg
2908 sv_cmp_flags
2909 sv_cmp_locale_flags
2910 sv_eq_flags
2911 sv_collxfrm_flags
5076a392 2912
1e463951 2913In some of these cases, the non-_flags functions have
5076a392
FC
2914been replaced with wrappers around the new functions.
2915
1e463951 2916=head3 pv/pvs/sv versions of existing functions
5076a392 2917
1e463951 2918Many functions ending with pvn now have equivalent pv/pvs/sv versions.
5076a392 2919
1e463951 2920=head3 List op-building functions
5076a392 2921
1e463951
FC
2922List op-building functions have been added to the
2923API. See L<op_append_elem|perlapi/op_append_elem>,
2924L<op_append_list|perlapi/op_append_list>, and
2925L<op_prepend_elem|perlapi/op_prepend_elem> in L<perlapi>.
5076a392 2926
1e463951 2927=head3 C<LINKLIST>
5076a392 2928
1e463951
FC
2929The L<LINKLIST|perlapi/LINKLIST> macro, part of op building that
2930constructs the execution-order op chain, has been added to the API.
5076a392 2931
1e463951 2932=head3 Localisation functions
5076a392 2933
1e463951
FC
2934The C<save_freeop>, C<save_op>, C<save_pushi32ptr> and C<save_pushptrptr>
2935functions have been added to the API.
5076a392 2936
1e463951 2937=head3 Stash names
5076a392 2938
1e463951
FC
2939A stash can now have a list of effective names in addition to its usual
2940name. The first effective name can be accessed via the C<HvENAME> macro,
2941which is now the recommended name to use in MRO linearisations (C<HvNAME>
2942being a fallback if there is no C<HvENAME>).
5076a392 2943
1e463951
FC
2944These names are added and deleted via C<hv_ename_add> and
2945C<hv_ename_delete>. These two functions are I<not> part of the API.
5076a392 2946
1e463951 2947=head3 New functions for finding and removing magic
5076a392 2948
1e463951
FC
2949The L<C<mg_findext()>|perlapi/mg_findext> and
2950L<C<sv_unmagicext()>|perlapi/sv_unmagicext>
2951functions have been added to the API.
2952They allow extension authors to find and remove magic attached to
2953scalars based on both the magic type and the magic virtual table, similar to how
2954C<sv_magicext()> attaches magic of a certain type and with a given virtual table
2955to a scalar. This eliminates the need for extensions to walk the list of
2956C<MAGIC> pointers of an C<SV> to find the magic that belongs to them.
5076a392 2957
1e463951 2958=head3 C<find_rundefsv>
5076a392 2959
1e463951
FC
2960This function returns the SV representing C<$_>, whether it's lexical
2961or dynamic.
5076a392 2962
1e463951 2963=head3 C<Perl_croak_no_modify>
5076a392 2964
1e463951
FC
2965C<Perl_croak_no_modify()> is short-hand for
2966C<Perl_croak("%s", PL_no_modify)>.
5076a392 2967
1e463951 2968=head3 C<PERL_STATIC_INLINE> define
5076a392 2969
1e463951
FC
2970The C<PERL_STATIC_INLINE> define has been added to provide the best-guess
2971incantation to use for static inline functions, if the C compiler supports
2972C99-style static inline. If it doesn't, it'll give a plain C<static>.
5076a392 2973
1e463951
FC
2974C<HAS_STATIC_INLINE> can be used to check if the compiler actually supports
2975inline functions.
5076a392 2976
1e463951 2977=head3 New C<pv_escape> option for hexadecimal escapes
5076a392 2978
1e463951
FC
2979A new option, C<PERL_PV_ESCAPE_NONASCII>, has been added to C<pv_escape> to
2980dump all characters above ASCII in hexadecimal. Before, one could get all
2981characters as hexadecimal or the Latin1 non-ASCII as octal.
5076a392 2982
1e463951 2983=head3 C<lex_start>
5076a392 2984
1e463951 2985C<lex_start> has been added to the API, but is considered experimental.
5076a392 2986
1e463951 2987=head3 C<op_scope()> and C<op_lvalue()>
5076a392 2988
1e463951
FC
2989The C<op_scope()> and C<op_lvalue()> functions have been added to the API,
2990but are considered experimental.
5076a392 2991
1e463951 2992=head2 C API Changes
5076a392 2993
1e463951 2994=head3 C<PERL_POLLUTE> has been removed
5076a392 2995
1e463951
FC
2996The option to define C<PERL_POLLUTE> to expose older 5.005 symbols for
2997backwards compatibility has been removed. It's use was always discouraged,
2998and MakeMaker contains a more specific escape hatch:
5076a392 2999
1e463951 3000 perl Makefile.PL POLLUTE=1
5076a392 3001
1e463951
FC
3002This can be used for modules that have not been upgraded to 5.6 naming
3003conventions (and really should be completely obsolete by now).
5076a392 3004
1e463951 3005=head3 Check API compatibility when loading XS modules
5076a392 3006
1e463951
FC
3007When perl's API changes in incompatible ways (which usually happens between
3008major releases), XS modules compiled for previous versions of perl will not
3009work anymore. They will need to be recompiled against the new perl.
5076a392 3010
1e463951
FC
3011In order to ensure that modules are recompiled, and to prevent users from
3012accidentally loading modules compiled for old perls into newer ones, the
3013C<XS_APIVERSION_BOOTCHECK> macro has been added. That macro, which is
3014called when loading every newly compiled extension, compares the API
3015version of the running perl with the version a module has been compiled for
3016and raises an exception if they don't match.
5076a392 3017
1e463951 3018=head3 Perl_fetch_cop_label
5076a392 3019
1e463951
FC
3020The first argument of the C API function C<Perl_fetch_cop_label> has changed
3021from C<struct refcounted he *> to C<COP *>, to insulate the user from
3022implementation details.
5076a392 3023
1e463951
FC
3024This API function was marked as "may change", and likely isn't in use outside
3025the core. (Neither an unpacked CPAN, nor Google's codesearch, finds any other
3026references to it.)
5076a392 3027
1e463951 3028=head3 GvCV() and GvGP() are no longer lvalues
5076a392 3029
1e463951
FC
3030The new GvCV_set() and GvGP_set() macros are now provided to replace
3031assignment to those two macros.
5076a392 3032
1e463951
FC
3033This allows a future commit to eliminate some backref magic between GV
3034and CVs, which will require complete control over assignment to the
3035gp_cv slot.
5076a392 3036
1e463951 3037=head3 CvGV() is no longer an lvalue
5076a392 3038
1e463951
FC
3039Under some circumstances, the C<CvGV()> field of a CV is now
3040reference-counted. To ensure consistent behaviour, direct assignment to
3041it, for example C<CvGV(cv) = gv> is now a compile-time error. A new macro,
3042C<CvGV_set(cv,gv)> has been introduced to perform this operation
3043safely. Note that modification of this field is not part of the public
3044API, regardless of this new macro (and despite its being listed in this section).
5076a392 3045
1e463951 3046=head3 CvSTASH() is no longer an lvalue
5076a392 3047
1e463951
FC
3048The C<CvSTASH()> macro can now only be used as an rvalue. C<CvSTASH_set()>
3049has been added to replace assignment to C<CvSTASH()>. This is to ensure
3050that backreferences are handled properly. These macros are not part of the
3051API.
5076a392 3052
1e463951 3053=head3 Calling conventions for C<newFOROP> and C<newWHILEOP>
5076a392 3054
1e463951
FC
3055The way the parser handles labels has been cleaned up and refactored. As a
3056result, the C<newFOROP()> constructor function no longer takes a parameter
3057stating what label is to go in the state op.
5076a392 3058
1e463951
FC
3059The C<newWHILEOP()> and C<newFOROP()> functions no longer accept a line
3060number as a parameter.
5076a392 3061
1e463951 3062=head3 Flags passed to C<uvuni_to_utf8_flags> and C<utf8n_to_uvuni>
5076a392 3063
1e463951
FC
3064Some of the flags parameters to uvuni_to_utf8_flags() and
3065utf8n_to_uvuni() have changed. This is a result of Perl's now allowing
5076a392
FC
3066internal storage and manipulation of code points that are problematic
3067in some situations. Hence, the default actions for these functions has
3068been complemented to allow these code points. The new flags are
3069documented in L<perlapi>. Code that requires the problematic code
483b16f3 3070points to be rejected needs to change to use the new flags. Some flag
5076a392
FC
3071names are retained for backward source compatibility, though they do
3072nothing, as they are now the default. However the flags
3073C<UNICODE_ALLOW_FDD0>, C<UNICODE_ALLOW_FFFF>, C<UNICODE_ILLEGAL>, and
3074C<UNICODE_IS_ILLEGAL> have been removed, as they stem from a
3075fundamentally broken model of how the Unicode non-character code points
3076should be handled, which is now described in
3077L<perlunicode/Non-character code points>. See also L</Selected Bug Fixes>.
3078
1e463951 3079XXX Which bugs in particular? Selected Bug Fixes is too long for this link
483b16f3
KW
3080to be meaningful right now
3081I don't see the bugs in that section currently -- khw
5076a392 3082
1e463951 3083=head2 Deprecated C APIs
5076a392 3084
1e463951 3085=over
5076a392 3086
1e463951 3087=item C<Perl_ptr_table_clear>
5076a392 3088
1e463951
FC
3089C<Perl_ptr_table_clear> is no longer part of Perl's public API. Calling it
3090now generates a deprecation warning, and it will be removed in a future
3091release.
5076a392 3092
1e463951 3093=item C<sv_compile_2op>
5076a392 3094
1e463951
FC
3095The C<sv_compile_2op()> API function is now deprecated. Searches suggest
3096that nothing on CPAN is using it, so this should have zero impact.
5076a392 3097
1e463951
FC
3098It attempted to provide an API to compile code down to an optree, but failed
3099to bind correctly to lexicals in the enclosing scope. It's not possible to
3100fix this problem within the constraints of its parameters and return value.
5076a392 3101
1e463951 3102=item C<find_rundefsvoffset>
5076a392 3103
1e463951
FC
3104The C<find_rundefsvoffset> function has been deprecated. It appeared that
3105its design was insufficient for reliably getting the lexical C<$_> at
3106run-time.
5076a392 3107
1e463951
FC
3108Use the new C<find_rundefsv> function or the C<UNDERBAR> macro
3109instead. They directly return the right SV representing C<$_>, whether it's
3110lexical or dynamic.
5076a392 3111
1e463951 3112=item C<CALL_FPTR> and C<CPERLscope>
5076a392 3113
1e463951
FC
3114Those are left from an old implementation of C<MULTIPLICITY> using C++ objects,
3115which was removed in Perl 5.8. Nowadays these macros do exactly nothing, so
3116they shouldn't be used anymore.
5076a392 3117
1e463951
FC
3118For compatibility, they are still defined for external C<XS> code. Only
3119extensions defining C<PERL_CORE> must be updated now.
5076a392 3120
1e463951 3121=back
5076a392 3122
1e463951 3123=head2 Other Internal Changes
5076a392 3124
1e463951 3125=head3 Stack unwinding
5076a392 3126
1e463951
FC
3127The protocol for unwinding the C stack at the last stage of a C<die>
3128has changed how it identifies the target stack frame. This now uses
3129a separate variable C<PL_restartjmpenv>, where previously it relied on
3130the C<blk_eval.cur_top_env> pointer in the C<eval> context frame that
3131has nominally just been discarded. This change means that code running
3132during various stages of Perl-level unwinding no longer needs to take
3133care to avoid destroying the ghost frame.
5076a392 3134
1e463951 3135=head3 Scope stack entries
5076a392 3136
1e463951
FC
3137The format of entries on the scope stack has been changed, resulting in a
3138reduction of memory usage of about 10%. In particular, the memory used by
3139the scope stack to record each active lexical variable has been halved.
5076a392 3140
1e463951 3141=head3 Memory allocation for pointer tables
5076a392 3142
1e463951
FC
3143Memory allocation for pointer tables has been changed. Previously
3144C<Perl_ptr_table_store> allocated memory from the same arena system as
3145C<SV> bodies and C<HE>s, with freed memory remaining bound to those arenas
3146until interpreter exit. Now it allocates memory from arenas private to the
3147specific pointer table, and that memory is returned to the system when
3148C<Perl_ptr_table_free> is called. Additionally, allocation and release are
3149both less CPU intensive.
5076a392 3150
1e463951 3151=head3 C<UNDERBAR>
5076a392 3152
1e463951
FC
3153The C<UNDERBAR> macro now calls C<find_rundefsv>. C<dUNDERBAR> is now a
3154noop but should still be used to ensure past and future compatibility.
5076a392 3155
1e463951 3156=head3 String comparison routines renamed
5076a392 3157
1e463951
FC
3158The ibcmp_* functions have been renamed and are now called foldEQ,
3159foldEQ_locale and foldEQ_utf8. The old names are still available as
3160macros.
3161
3162=head3 C<chop> and C<chomp> implementations merged
3163
3164The opcode bodies for C<chop> and C<chomp> and for C<schop> and C<schomp>
3165have been merged. The implementation functions C<Perl_do_chop()> and
3166C<Perl_do_chomp()>, never part of the public API, have been merged and
3167moved to a static function in F<pp.c>. This shrinks the perl binary
3168slightly, and should not affect any code outside the core (unless it is
3169relying on the order of side effects when C<chomp> is passed a I<list> of
3170values).
5076a392
FC
3171
3172=head1 Selected Bug Fixes
3173
e8e35311
FC
3174=head2 I/O
3175
5076a392
FC
3176=over 4
3177
3178=item *
3179
e8e35311 3180Perl no longer produces this warning:
a593b319
FC
3181
3182 $ perl -we 'open my $f, ">", \my $x; binmode $f, "scalar"'
3183 Use of uninitialized value in binmode at -e line 1.
3184
3185=item *
3186
e8e35311
FC
3187Opening a glob reference via C<< open $fh, "E<gt>", \*glob >> will no longer
3188cause the glob to be corrupted when the filehandle is printed to. This would
3189cause perl to crash whenever the glob's contents were accessed
3190[perl #77492].
4ed2cea4
FC
3191
3192=item *
3193
e8e35311
FC
3194PerlIO no longer crashes when called recursively, e.g., from a signal
3195handler. Now it just leaks memory [perl #75556].
4ed2cea4
FC
3196
3197=item *
3198
e8e35311
FC
3199Most I/O functions were not warning for unopened handles unless the
3200'closed' and 'unopened' warnings categories were both enabled. Now only
3201C<use warnings 'unopened'> is necessary to trigger these warnings (as was
438c239f 3202always meant to be the case).
4ed2cea4
FC
3203
3204=item *
3205
438c239f 3206There have been several fixes to PerlIO layers:
e8e35311 3207
438c239f
FC
3208When C<binmode FH, ":crlf"> pushes the C<:crlf> layer on top of the stack,
3209it no longer enables crlf layers lower in the stack, to avoid unexpected
3210results [perl #38456].
4ed2cea4 3211
438c239f
FC
3212Opening a file in C<:raw> mode now does what it advertises to do (first
3213open the file, then binmode it), instead of simply leaving off the top
3214layer [perl #80764].
5076a392 3215
438c239f
FC
3216The three layers C<:pop>, C<:utf8> and C<:bytes> didn't allow stacking when
3217opening a file. For example
e8e35311 3218this:
5076a392 3219
e8e35311 3220 open FH, '>:pop:perlio', 'some.file' or die $!;
5076a392 3221
438c239f
FC
3222Would throw an error: "Invalid argument". This has been fixed in this
3223release [perl #82484].
5076a392 3224
e8e35311
FC
3225=back
3226
3227=head2 Regular Expression Bug Fixes
3228
3229=over
5076a392
FC
3230
3231=item *
3232
e8e35311
FC
3233The regular expression engine no longer loops when matching
3234C<"\N{LATIN SMALL LIGATURE FF}" =~ /f+/i> and similar expressions
cdc10f43 3235[perl #72998] (5.12.1).
5076a392
FC
3236
3237=item *
3238
e8e35311
FC
3239The trie runtime code should no longer allocate massive amounts of memory,
3240fixing #74484.
5076a392
FC
3241
3242=item *
3243
438c239f
FC
3244Syntax errors in C<< (?{...}) >> blocks no longer cause panic messages
3245[perl #2353].
5076a392
FC
3246
3247=item *
3248
438c239f
FC
3249A pattern like C<(?:(o){2})?> no longer causes a "panic" error
3250[perl #39233].
5076a392
FC
3251
3252=item *
3253
438c239f 3254A fatal error in regular expressions containing C<(.*?)> when processing
d430b8e7 3255UTF-8 data has been fixed [perl #75680] (5.12.2).
5076a392
FC
3256
3257=item *
3258
e8e35311 3259An erroneous regular expression engine optimisation that caused regex verbs like
438c239f 3260C<*COMMIT> sometimes to be ignored has been removed.
5076a392
FC
3261
3262=item *
3263
e8e35311
FC
3264The regular expression bracketed character class C<[\8\9]> was effectively the
3265same as C<[89\000]>, incorrectly matching a NULL character. It also gave
3266incorrect warnings that the C<8> and C<9> were ignored. Now C<[\8\9]> is the
3267same as C<[89]> and gives legitimate warnings that C<\8> and C<\9> are
3268unrecognized escape sequences, passed-through.
5076a392
FC
3269
3270=item *
3271
e8e35311
FC
3272A regular expression match in the right-hand side of a global substitution
3273(C<s///g>) that is in the same scope will no longer cause match variables
3274to have the wrong values on subsequent iterations. This can happen when an
3275array or hash subscript is interpolated in the right-hand side, as in
3276C<s|(.)|@a{ print($1), /./ }|g> [perl #19078].
5076a392
FC
3277
3278=item *
3279
438c239f
FC
3280Several cases in which characters in the Latin-1 non-ASCII range (0x80 to
32810xFF) used not to match themselves or used to match both a character class
3282and its complement have been fixed. For instance, U+00E2 could match both
3283C<\w> and C<\W> [perl #78464] [perl #18281] [perl #60156].
5076a392
FC
3284
3285=item *
3286
e8e35311
FC
3287Matching a Unicode character against an alternation containing characters
3288that happened to match continuation bytes in the former's UTF8
3289representation (C<qq{\x{30ab}} =~ /\xab|\xa9/>) would cause erroneous
3290warnings [perl #70998].
5076a392
FC
3291
3292=item *
3293
e8e35311
FC
3294The trie optimisation was not taking empty groups into account, preventing
3295'foo' from matching C</\A(?:(?:)foo|bar|zot)\z/> [perl #78356].
5076a392
FC
3296
3297=item *
3298
e8e35311
FC
3299A pattern containing a C<+> inside a lookahead would sometimes cause an
3300incorrect match failure in a global match (e.g., C</(?=(\S+))/g>)
3301[perl #68564].
5076a392
FC
3302
3303=item *
3304
e8e35311
FC
3305A regular expression optimisation would sometimes cause a match with a
3306C<{n,m}> quantifier to fail when it should match [perl #79152].
5076a392
FC
3307
3308=item *
3309
e8e35311 3310Case insensitive matching in regular expressions compiled under C<use
438c239f
FC
3311locale> now works much more sanely when the pattern or
3312target string is encoded internally in
3313UTF8. Previously, under these conditions the localeness
e8e35311
FC
3314was completely lost. Now, code points above 255 are treated as Unicode,
3315but code points between 0 and 255 are treated using the current locale
438c239f
FC
3316rules, regardless of whether the pattern or the string is encoded in UTF8.
3317The few case-insensitive matches that cross the 255/256 boundary are not
e8e35311
FC
3318allowed. For example, 0xFF does not caselessly match the character at
33190x178, LATIN CAPITAL LETTER Y WITH DIAERESIS, because 0xFF may not be
3320LATIN SMALL LETTER Y in the current locale, and Perl has no way of
3321knowing if that character even exists in the locale, much less what code
3322point it is.
5076a392
FC
3323
3324=item *
3325
e8e35311
FC
3326The C<(?|...)> regular expression construct no longer crashes if the final
3327branch has more sets of capturing parentheses than any other branch. This
3328was fixed in Perl 5.10.1 for the case of a single branch, but that fix did
3329not take multiple branches into account [perl #84746].
5076a392
FC
3330
3331=item *
3332
e8e35311
FC
3333A bug has been fixed in the implementation of C<{...}> quantifiers in
3334regular expressions that prevented the code block in
3335C</((\w+)(?{ print $2 })){2}/> from seeing the C<$2> sometimes
3336[perl #84294].
5076a392 3337
e8e35311 3338=back
5076a392 3339
e8e35311
FC
3340=head2 Syntax/Parsing Bugs
3341
3342=over
5076a392
FC
3343
3344=item *
3345
e8e35311 3346C<when(scalar){...}> no longer crashes, but produces a syntax error
cdc10f43 3347[perl #74114] (5.12.1).
5076a392
FC
3348
3349=item *
3350
e8e35311
FC
3351A label right before a string eval (C<foo: eval $string>) no longer causes
3352the label to be associated also with the first statement inside the eval
3353[perl #74290] (5.12.1).
5076a392
FC
3354
3355=item *
3356
b2c076b5 3357The C<no 5.13.2;> form of C<no> no longer tries to turn on features or
d430b8e7 3358pragmata (i.e., strict) [perl #70075] (5.12.2).
5076a392
FC
3359
3360=item *
3361
b2c076b5
FC
3362C<BEGIN {require 5.12.0}> now behaves as documented, rather than behaving
3363identically to C<use 5.12.0;>. Previously, C<require> in a C<BEGIN> block
3364was erroneously executing the C<use feature ':5.12.0'> and
3365C<use strict;> behaviour, which only C<use> was documented to
3366provide [perl #69050].
5076a392
FC
3367
3368=item *
3369
5076a392
FC
3370A regression introduced in Perl 5.12.0, making
3371C<< my $x = 3; $x = length(undef) >> result in C<$x> set to C<3> has been
d430b8e7 3372fixed. C<$x> will now be C<undef> [perl #85508] (5.12.2).
b2c076b5
FC
3373
3374=item *
3375
3376When strict 'refs' mode is off, C<%{...}> in rvalue context returns
3377C<undef> if its argument is undefined. An optimisation introduced in perl
33785.12.0 to make C<keys %{...}> faster when used as a boolean did not take
3379this into account, causing C<keys %{+undef}> (and C<keys %$foo> when
3380C<$foo> is undefined) to be an error, which it should only be in strict
3381mode [perl #81750].
5076a392
FC
3382
3383=item *
3384
e8e35311 3385Constant-folding used to cause
5076a392 3386
e8e35311 3387 $text =~ ( 1 ? /phoo/ : /bear/)
5076a392 3388
e8e35311
FC
3389to turn into
3390
3391 $text =~ /phoo/
3392
3393at compile time. Now it correctly matches against C<$_> [perl #20444].
5076a392
FC
3394
3395=item *
3396
e8e35311
FC
3397Parsing Perl code (either with string C<eval> or by loading modules) from
3398within a C<UNITCHECK> block no longer causes the interpreter to crash
3399[perl #70614].
5076a392
FC
3400
3401=item *
3402
b2c076b5
FC
3403String evals no longer fail after 2 billion scopes have been
3404compiled [perl #83364].
3405
3406=item *
3407
e8e35311
FC
3408The parser no longer hangs when encountering certain Unicode characters,
3409such as U+387 [perl #74022].
5076a392
FC
3410
3411=item *
3412
b2c076b5
FC
3413Several contexts no longer allow a Unicode character to begin a word
3414that should never begin words, for an example an accent that must follow
3415another character previously could precede all other characters.
5076a392
FC
3416
3417=item *
3418
e8e35311
FC
3419Defining a constant with the same name as one of perl's special blocks
3420(e.g., INIT) stopped working in 5.12.0, but has now been fixed
3421[perl #78634].
5076a392
FC
3422
3423=item *
3424
e8e35311
FC
3425A reference to a literal value used as a hash key (C<$hash{\"foo"}>) used
3426to be stringified, even if the hash was tied [perl #79178].
5076a392
FC
3427
3428=item *
3429
e8e35311
FC
3430A closure containing an C<if> statement followed by a constant or variable
3431is no longer treated as a constant [perl #63540].
5076a392
FC
3432
3433=item *
3434
e8e35311
FC
3435C<state> can now be used with attributes. It used to mean the same thing as
3436C<my> if attributes were present [perl #68658].
5076a392
FC
3437
3438=item *
3439
e8e35311
FC
3440Expressions like C<< @$a > 3 >> no longer cause C<$a> to be mentioned in
3441the "Use of uninitialized value in numeric gt" warning when C<$a> is
3442undefined (since it is not part of the C<E<gt>> expression, but the operand
3443of the C<@>) [perl #72090].
5076a392
FC
3444
3445=item *
3446
e8e35311
FC
3447Accessing an element of a package array with a hard-coded number (as
3448opposed to an arbitrary expression) would crash if the array did not exist.
3449Usually the array would be autovivified during compilation, but typeglob
3450manipulation could remove it, as in these two cases which used to crash:
5076a392 3451
e8e35311
FC
3452 *d = *a; print $d[0];
3453 undef *d; print $d[0];
5076a392 3454
2c389f6c
FC
3455=item *
3456
3457The C<-C> command line option, when used on the shebang line, can now be
3458followed by other options [perl #72434].
3459
3460=item *
3461
3462The C<B> module was returning C<B::OP>s instead of C<B::LOGOP>s for C<entertry> [perl #80622].
3463This was due to a bug in the perl core, not in C<B> itself.
3464
e8e35311 3465=back
5076a392 3466
e262cb24
FC
3467=head2 Stashes, Globs and Method Lookup
3468
3469Perl 5.10.0 introduced a new internal mechanism for caching MROs (method
3470resolution orders, or lists of parent classes; aka "isa" caches) to make
3471method lookup faster (so @ISA arrays would not have to be searched
3472repeatedly). Unfortunately, this brought with it quite a few bugs. Almost
3473all of these have been fixed now, along with a few MRO-related bugs that
3474existed before 5.10.0:
3475
3476=over
3477
3478=item *
3479
3480The following used to have erratic effects on method resolution, because
3481the "isa" caches were not reset or otherwise ended up listing the wrong
3482classes. These have been fixed.
3483
3484=over
3485
3486=item Aliasing packages by assigning to globs [perl #77358]
3487
3488=item Deleting packages by deleting their containing stash elements
3489
3490=item Undefining the glob containing a package (C<undef *Foo::>)
3491
3492=item Undefining an ISA glob (C<undef *Foo::ISA>)
3493
3494=item Deleting an ISA stash element (C<delete $Foo::{ISA}>)
3495
3496=item Sharing @ISA arrays between classes (via C<*Foo::ISA = \@Bar::ISA> or
3497C<*Foo::ISA = *Bar::ISA>) [perl #77238]
3498
3499=back
3500
3501C<undef *Foo::ISA> would even stop a new C<@Foo::ISA> array from updating
3502caches.
3503
3504=item *
3505
3506Typeglob assignments would crash if the glob's stash no longer existed, so
3507long as the glob assigned to was named 'ISA' or the glob on either side of
3508the assignment contained a subroutine.
3509
3510=item *
3511
3512C<PL_isarev>, which is accessible to Perl via C<mro::get_isarev> is now
3513updated properly when packages are deleted or removed from the C<@ISA> of
3514other classes. This allows many packages to be created and deleted without
3515causing a memory leak [perl #75176].
3516
3517=back
3518
3519In addition, various other bugs related to typeglobs and stashes have been
3520fixed:
5076a392 3521
e8e35311 3522=over
5076a392
FC
3523
3524=item *
3525
e8e35311 3526Some work has been done on the internal pointers that link between symbol
e262cb24 3527tables (stashes), typeglobs and subroutines. This has the effect that
e8e35311
FC
3528various edge cases related to deleting stashes or stash entries (e.g.
3529<%FOO:: = ()>), and complex typeglob or code reference aliasing, will no
3530longer crash the interpreter.
5076a392
FC
3531
3532=item *
3533
e262cb24
FC
3534Assigning a reference to a glob copy now assigns to a glob slot instead of
3535overwriting the glob with a scalar [perl #1804] [perl #77508].
5076a392
FC
3536
3537=item *
3538
e8e35311
FC
3539A bug when replacing the glob of a loop variable within the loop has been fixed
3540[perl #21469]. This
3541means the following code will no longer crash:
5076a392 3542
e8e35311
FC
3543 for $x (...) {
3544 *x = *y;
3545 }
5076a392
FC
3546
3547=item *
3548
3549Assigning a glob to a PVLV used to convert it to a plain string. Now it
3550works correctly, and a PVLV can hold a glob. This would happen when a
3551nonexistent hash or array element was passed to a subroutine:
3552
3553 sub { $_[0] = *foo }->($hash{key});
3554 # $_[0] would have been the string "*main::foo"
3555
3556It also happened when a glob was assigned to, or returned from, an element
3557of a tied array or hash [perl #36051].
3558
3559=item *
44691e6f 3560
e8e35311 3561When trying to report C<Use of uninitialized value $Foo::BAR>, crashes could
e262cb24
FC
3562occur if the glob holding the global variable in question had been detached