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Correct the B::Deparse version in perldelta
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1=encoding utf8
2
3=head1 NAME
4
5076a392 5perldelta - what is new for perl v5.14.0
c71a852f 6
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7=head1 DESCRIPTION
8
9This document describes differences between the 5.12.0 release and
10the 5.14.0 release.
11
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12If you are upgrading from an earlier release such as 5.10.0, first read
13L<perl5120delta>, which describes differences between 5.10.0 and
145.12.0.
15
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16Some of the bug fixes in this release have been backported to subsequent
17releases of 5.12.x. Those are indicated with the 5.12.x version in
18parentheses.
19
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20=head1 Notice
21
22XXX Any important notices here
23
24=head1 Core Enhancements
25
1f539a1a 26=head2 Unicode
5076a392 27
1f539a1a 28=head3 Unicode Version 6.0 is now supported (mostly)
5076a392 29
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30Perl comes with the Unicode 6.0 data base updated with
31L<Corrigendum #8|http://www.unicode.org/versions/corrigendum8.html>,
32with one exception noted below.
33See L<http://unicode.org/versions/Unicode6.0.0> for details on the new
34release. Perl does not support any Unicode provisional properties,
a3c24add 35including the new ones for this release.
5076a392 36
1f539a1a 37Unicode 6.0 has chosen to use the name C<BELL> for the character at U+1F514,
e1b1739f 38which is a symbol that looks like a bell, and is used in Japanese cell
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39phones. This conflicts with the long-standing Perl usage of having
40C<BELL> mean the ASCII C<BEL> character, U+0007. In Perl 5.14,
41C<\N{BELL}> will continue to mean U+0007, but its use will generate a
42deprecated warning message, unless such warnings are turned off. The
43new name for U+0007 in Perl will be C<ALERT>, which corresponds nicely
44with the existing shorthand sequence for it, C<"\a">. C<\N{BEL}> will
45mean U+0007, with no warning given. The character at U+1F514 will not
46have a name in 5.14, but can be referred to by C<\N{U+1F514}>. The plan
47is that in Perl 5.16, C<\N{BELL}> will refer to U+1F514, and so all code
48that uses C<\N{BELL}> should convert by then to using C<\N{ALERT}>,
49C<\N{BEL}>, or C<"\a"> instead.
5076a392 50
1f539a1a 51=head3 Full functionality for C<use feature 'unicode_strings'>
5076a392 52
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53This release provides full functionality for C<use feature
54'unicode_strings'>. Under its scope, all string operations executed and
55regular expressions compiled (even if executed outside its scope) have
56Unicode semantics. See L<feature>.
5076a392 57
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58This feature avoids most forms of the "Unicode Bug" (See
59L<perlunicode/The "Unicode Bug"> for details.) If there is a
60possibility that your code will process Unicode strings, you are
61B<strongly> encouraged to use this subpragma to avoid nasty surprises.
5076a392 62
1f539a1a 63=head3 C<\N{I<name>}> and C<charnames> enhancements
5076a392 64
1f539a1a 65=over
5076a392 66
1f539a1a 67=item *
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68
69C<\N{}> and C<charnames::vianame> now know about the abbreviated
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70character names listed by Unicode, such as NBSP, SHY, LRO, ZWJ, etc., all
71the customary abbreviations for the C0 and C1 control characters (such as
72ACK, BEL, CAN, etc.), and a few new variants of some C1 full names that
73are in common usage.
5076a392 74
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75=item *
76
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77Unicode has a number of named character sequences, in which particular sequences
78of code points are given names. C<\N{...}> now recognizes these.
79
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80=item *
81
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82C<\N{}>, C<charnames::vianame>, C<charnames::viacode> now know about every
83character in Unicode. Previously, they didn't know about the Hangul syllables
84nor a number of CJK (Chinese/Japanese/Korean) characters.
85
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86=item *
87
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88In the past, it was ineffective to override one of Perl's abbreviations
89with your own custom alias. Now it works.
90
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91=item *
92
e1b1739f 93You can also create a custom alias of the ordinal of a
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94character, known by C<\N{...}>, C<charnames::vianame()>, and
95C<charnames::viacode()>. Previously, an alias had to be to an official
96Unicode character name. This made it impossible to create an alias for
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97a code point that had no name, such as those reserved for private
98use.
5076a392 99
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100=item *
101
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102A new function, C<charnames::string_vianame()>, has been added.
103This function is a run-time version of C<\N{...}>, returning the string
104of characters whose Unicode name is its parameter. It can handle
105Unicode named character sequences, whereas the pre-existing
106C<charnames::vianame()> cannot, as the latter returns a single code
107point.
108
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109=back
110
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111See L<charnames> for details on all these changes.
112
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113=head3 New warnings categories for problematic (non-)Unicode code points.
114
115Three new warnings subcategories of "utf8" have been added. These
116allow you to turn off some "utf8" warnings, while allowing
117others warnings to remain on. The three categories are:
118C<surrogate> when UTF-16 surrogates are encountered;
119C<nonchar> when Unicode non-character code points are encountered;
120and C<non_unicode> when code points that are above the legal Unicode
121maximum of 0x10FFFF are encountered.
122
1f539a1a 123=head3 Any unsigned value can be encoded as a character
5076a392 124
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125With this release, Perl is adopting a model that any unsigned value can
126be treated as a code point and encoded internally (as utf8) without
54c7bb16 127warnings - not just the code points that are legal in Unicode.
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128However, unless utf8 or the corresponding sub-category (see previous
129item) warnings have been
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130explicitly lexically turned off, outputting or performing a
131Unicode-defined operation (such as upper-casing) on such a code point
132will generate a warning. Attempting to input these using strict rules
133(such as with the C<:encoding('UTF-8')> layer) will continue to fail.
134Prior to this release the handling was very inconsistent, and incorrect
135in places. Also, the Unicode non-characters, some of which previously were
136erroneously considered illegal in places by Perl, contrary to the Unicode
137standard, are now always legal internally. But inputting or outputting
138them will work the same as for the non-legal Unicode code points, as the
139Unicode standard says they are illegal for "open interchange".
5076a392 140
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141=head3 Unicode database files not installed
142
143The Unicode database files are no longer installed with Perl. This
144doesn't affect any functionality in Perl and saves significant disk
145space. If you previously were explicitly opening and reading those
146files, you can download them from
147L<http://www.unicode.org/Public/zipped/6.0.0/>.
148
1f539a1a 149=head2 Regular Expressions
5076a392 150
1f539a1a 151=head3 C<(?^...)> construct to signify default modifiers
5076a392 152
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153An ASCII caret (also called a "circumflex accent") C<"^">
154immediately following a C<"(?"> in a regular expression
155now means that the subexpression does not inherit the
156surrounding modifiers such as C</i>, but reverts to the
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157Perl defaults. Any modifiers following the caret override the defaults.
158
159The stringification of regular expressions now uses this
160notation. E.g., before, C<qr/hlagh/i> would be stringified as
161C<(?i-xsm:hlagh)>, but now it's stringified as C<(?^i:hlagh)>.
162
163The main purpose of this is to allow tests that rely on the
e1b1739f 164stringification not to have to change when new modifiers are added.
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165See L<perlre/Extended Patterns>.
166
1f539a1a 167=head3 C</d>, C</l>, C</u>, C</a>, and C</aa> modifiers
5076a392 168
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169Four new regular expression modifiers have been added. These are mutually
170exclusive; one only can be turned on at a time.
5076a392 171
959ad7d5 172The C</l> modifier says to compile the regular expression as if it were
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173in the scope of C<use locale>, even if it is not.
174
959ad7d5 175The C</u> modifier says to compile the regular expression as if it were
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176in the scope of a C<use feature "unicode_strings"> pragma.
177
e1b1739f 178The C</d> (default) modifier is used to override any C<use locale> and
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179C<use feature "unicode_strings"> pragmas that are in effect at the time
180of compiling the regular expression.
181
959ad7d5 182The C</a> regular expression modifier restricts C<\s>, C<\d> and C<\w> and
7baaf023 183the Posix (C<[[:posix:]]>) character classes to the ASCII range. Their
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184complements and C<\b> and C<\B> are correspondingly
185affected. Otherwise, C</a> behaves like the C</u> modifier, in that
e1b1739f 186case-insensitive matching uses Unicode semantics.
5076a392 187
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188The C</aa> modifier is like C</a>, except that, in case-insensitive matching, no ASCII character will match a
189non-ASCII character. For example,
5076a392 190
959ad7d5 191 'k' =~ /\N{KELVIN SIGN}/ai
5076a392 192
959ad7d5 193will match; it won't under C</aa>.
5076a392 194
959ad7d5 195See L<perlre/Modifiers> for more detail.
5076a392 196
1f539a1a 197=head3 Non-destructive substitution
5076a392 198
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199The substitution (C<s///>) and transliteration
200(C<y///>) operators now support an C</r> option that
201copies the input variable, carries out the substitution on
202the copy and returns the result. The original remains unmodified.
5076a392 203
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204 my $old = 'cat';
205 my $new = $old =~ s/cat/dog/r;
206 # $old is 'cat' and $new is 'dog'
5076a392 207
1f539a1a 208This is particularly useful with C<map>. See L<perlop> for more examples.
5076a392 209
1f539a1a 210=head3 Reentrant regular expression engine
5076a392 211
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212It is now safe to use regular expressions within C<(?{...})> and
213C<(??{...})> code blocks inside regular expressions.
5076a392 214
1f539a1a 215These block are still experimental, however, and still have problems with
e1b1739f 216lexical (C<my>) variables and abnormal exiting.
5076a392 217
1f539a1a 218=head3 C<use re '/flags';>
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219
220The C<re> pragma now has the ability to turn on regular expression flags
221till the end of the lexical scope:
222
223 use re '/x';
224 "foo" =~ / (.+) /; # /x implied
225
226See L<re/"'/flags' mode"> for details.
227
1f539a1a 228=head3 \o{...} for octals
5076a392 229
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230There is a new octal escape sequence, C<"\o">, in double-quote-like
231contexts. This construct allows large octal ordinals beyond the
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232current max of 0777 to be represented. It also allows you to specify a
233character in octal which can safely be concatenated with other regex
234snippets and which won't be confused with being a backreference to
235a regex capture group. See L<perlre/Capture groups>.
236
237=head3 Add C<\p{Titlecase}> as a synonym for C<\p{Title}>
238
239This synonym is added for symmetry with the Unicode property names
240C<\p{Uppercase}> and C<\p{Lowercase}>.
5076a392 241
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242=head3 Regular expression debugging output improvement
243
244Regular expression debugging output (turned on by C<use re 'debug';>) now
245uses hexadecimal when escaping non-ASCII characters, instead of octal.
246
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247=head3 Return value of C<delete $+{...}>
248
249Custom regular expression engines can now determine the return value of
250C<delete> on an entry of C<%+> or C<%->.
251
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252=head2 Syntactical Enhancements
253
254=head3 Array and hash container functions accept references
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255
256All built-in functions that operate directly on array or hash
257containers now also accept hard references to arrays or hashes:
258
259 |----------------------------+---------------------------|
260 | Traditional syntax | Terse syntax |
261 |----------------------------+---------------------------|
262 | push @$arrayref, @stuff | push $arrayref, @stuff |
263 | unshift @$arrayref, @stuff | unshift $arrayref, @stuff |
264 | pop @$arrayref | pop $arrayref |
265 | shift @$arrayref | shift $arrayref |
266 | splice @$arrayref, 0, 2 | splice $arrayref, 0, 2 |
267 | keys %$hashref | keys $hashref |
268 | keys @$arrayref | keys $arrayref |
269 | values %$hashref | values $hashref |
270 | values @$arrayref | values $arrayref |
271 | ($k,$v) = each %$hashref | ($k,$v) = each $hashref |
272 | ($k,$v) = each @$arrayref | ($k,$v) = each $arrayref |
273 |----------------------------+---------------------------|
274
275This allows these built-in functions to act on long dereferencing chains
276or on the return value of subroutines without needing to wrap them in
277C<@{}> or C<%{}>:
278
279 push @{$obj->tags}, $new_tag; # old way
280 push $obj->tags, $new_tag; # new way
281
282 for ( keys %{$hoh->{genres}{artists}} ) {...} # old way
283 for ( keys $hoh->{genres}{artists} ) {...} # new way
284
285For C<push>, C<unshift> and C<splice>, the reference will auto-vivify
286if it is not defined, just as if it were wrapped with C<@{}>.
287
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288For C<keys>, C<values>, C<each>, when overloaded dereferencing is
289present, the overloaded dereference is used instead of dereferencing the
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290underlying reftype. Warnings are issued about assumptions made in
291ambiguous cases.
5076a392 292
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293=head3 Single term prototype
294
295The C<+> prototype is a special alternative to C<$> that will act like
296C<\[@%]> when given a literal array or hash variable, but will otherwise
e1b1739f 297force scalar context on the argument. See L<perlsub/Prototypes>.
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298
299=head3 C<package> block syntax
300
301A package declaration can now contain a code block, in which case the
302declaration is in scope only inside that block. So C<package Foo { ... }>
303is precisely equivalent to C<{ package Foo; ... }>. It also works with
304a version number in the declaration, as in C<package Foo 1.2 { ... }>.
e1b1739f 305See L<perlfunc>.
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306
307=head3 Statement labels can appear in more places
308
309Statement labels can now occur before any type of statement or declaration,
310such as C<package>.
311
312=head3 Stacked labels
313
314Multiple statement labels can now appear before a single statement.
315
316=head3 Uppercase X/B allowed in hexadecimal/binary literals
317
318Literals may now use either upper case C<0X...> or C<0B...> prefixes,
319in addition to the already supported C<0x...> and C<0b...>
e1b1739f 320syntax [perl #76296].
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321
322C, Ruby, Python and PHP already supported this syntax, and it makes
323Perl more internally consistent. A round-trip with C<eval sprintf
e1b1739f 324"%#X", 0x10> now returns C<16>, the way C<eval sprintf "%#x", 0x10> does.
1f539a1a 325
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326=head3 Overridable tie functions
327
328C<tie>, C<tied> and C<untie> can now be overridden [perl #75902].
329
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330=head2 Exception Handling
331
332Several changes have been made to the way C<die>, C<warn>, and C<$@>
333behave, in order to make them more reliable and consistent.
334
335When an exception is thrown inside an C<eval>, the exception is no
336longer at risk of being clobbered by code running during unwinding
337(e.g., destructors). Previously, the exception was written into C<$@>
338early in the throwing process, and would be overwritten if C<eval> was
339used internally in the destructor for an object that had to be freed
340while exiting from the outer C<eval>. Now the exception is written
341into C<$@> last thing before exiting the outer C<eval>, so the code
342running immediately thereafter can rely on the value in C<$@> correctly
343corresponding to that C<eval>. (C<$@> is still also set before exiting the
344C<eval>, for the sake of destructors that rely on this.)
345
346Likewise, a C<local $@> inside an C<eval> will no longer clobber any
347exception thrown in its scope. Previously, the restoration of C<$@> upon
348unwinding would overwrite any exception being thrown. Now the exception
349gets to the C<eval> anyway. So C<local $@> is safe before a C<die>.
350
351Exceptions thrown from object destructors no longer modify the C<$@>
352of the surrounding context. (If the surrounding context was exception
353unwinding, this used to be another way to clobber the exception being
354thrown.) Previously such an exception was
355sometimes emitted as a warning, and then either was
356string-appended to the surrounding C<$@> or completely replaced the
357surrounding C<$@>, depending on whether that exception and the surrounding
358C<$@> were strings or objects. Now, an exception in this situation is
359always emitted as a warning, leaving the surrounding C<$@> untouched.
360In addition to object destructors, this also affects any function call
361performed by XS code using the C<G_KEEPERR> flag.
362
363Warnings for C<warn> can now be objects, in the same way as exceptions
364for C<die>. If an object-based warning gets the default handling,
365of writing to standard error, it is stringified as
366before, with the file and line number appended. But
367a C<$SIG{__WARN__}> handler will now receive an
368object-based warning as an object, where previously it was passed the
369result of stringifying the object.
370
371=head2 Other Enhancements
372
373=head3 Assignment to C<$0> sets the legacy process name with C<prctl()> on Linux
374
375On Linux the legacy process name will be set with L<prctl(2)>, in
376addition to altering the POSIX name via C<argv[0]> as perl has done
377since version 4.000. Now system utilities that read the legacy process
378name such as ps, top and killall will recognize the name you set when
379assigning to C<$0>. The string you supply will be cut off at 16 bytes,
380this is a limitation imposed by Linux.
381
382=head3 C<srand()> now returns the seed
383
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384This allows programs that need to have repeatable results not to have to come
385up with their own seed-generating mechanism. Instead, they can use C<srand()>
386and stash the return value for future use. Typical is a test program which
1f539a1a 387has too many combinations to test comprehensively in the time available to it
e1b1739f 388each run. It can test a random subset each time and, should there be a failure,
1f539a1a 389log the seed used for that run so that it can later be used to reproduce the
e1b1739f 390same results.
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391
392=head3 printf-like functions understand post-1980 size modifiers
393
394Perl's printf and sprintf operators, and Perl's internal printf replacement
395function, now understand the C90 size modifiers "hh" (C<char>), "z"
396(C<size_t>), and "t" (C<ptrdiff_t>). Also, when compiled with a C99
397compiler, Perl now understands the size modifier "j" (C<intmax_t>).
398
399So, for example, on any modern machine, C<sprintf('%hhd', 257)> returns '1'.
400
401=head3 New global variable C<${^GLOBAL_PHASE}>
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402
403A new global variable, C<${^GLOBAL_PHASE}>, has been added to allow
404introspection of the current phase of the perl interpreter. It's explained in
405detail in L<perlvar/"${^GLOBAL_PHASE}"> and
406L<perlmod/"BEGIN, UNITCHECK, CHECK, INIT and END">.
407
1f539a1a 408=head3 C<-d:-foo> calls C<Devel::foo::unimport>
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409
410The syntax C<-dI<B<:>foo>> was extended in 5.6.1 to make C<-dI<:fooB<=bar>>>
411equivalent to C<-MDevel::foo=bar>, which expands
412internally to C<use Devel::foo 'bar';>.
413F<perl> now allows prefixing the module name with C<->, with the same
414semantics as C<-M>, I<i.e.>
415
416=over 4
417
418=item C<-d:-foo>
419
420Equivalent to C<-M-Devel::foo>, expands to
421C<no Devel::foo;>, calls C<< Devel::foo->unimport() >>
422if the method exists.
423
424=item C<-d:-foo=bar>
425
426Equivalent to C<-M-Devel::foo=bar>, expands to C<no Devel::foo 'bar';>,
427calls C<< Devel::foo->unimport('bar') >> if the method exists.
428
429=back
430
e1b1739f 431This is particularly useful for suppressing the default actions of a
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432C<Devel::*> module's C<import> method whilst still loading it for debugging.
433
1f539a1a 434=head3 Filehandle method calls load L<IO::File> on demand
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435
436When a method call on a filehandle would die because the method cannot
437be resolved, and L<IO::File> has not been loaded, Perl now loads L<IO::File>
438via C<require> and attempts method resolution again:
439
440 open my $fh, ">", $file;
441 $fh->binmode(":raw"); # loads IO::File and succeeds
442
443This also works for globs like STDOUT, STDERR and STDIN:
444
445 STDOUT->autoflush(1);
446
447Because this on-demand load only happens if method resolution fails, the
448legacy approach of manually loading an L<IO::File> parent class for partial
449method support still works as expected:
450
451 use IO::Handle;
452 open my $fh, ">", $file;
453 $fh->autoflush(1); # IO::File not loaded
454
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455=head3 IPv6 support
456
457The C<Socket> module provides new affordances for IPv6,
458including implementations of the C<Socket::getaddrinfo()> and
459C<Socket::getnameinfo()> functions, along with related constants, and a
460handful of new functions. See L<Socket>.
461
1f539a1a 462=head3 DTrace probes now include package name
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463
464The DTrace probes now include an additional argument (C<arg3>) which contains
465the package the subroutine being entered or left was compiled in.
466
467For example using the following DTrace script:
468
469 perl$target:::sub-entry
470 {
471 printf("%s::%s\n", copyinstr(arg0), copyinstr(arg3));
472 }
473
474and then running:
475
476 perl -e'sub test { }; test'
477
478DTrace will print:
479
480 main::test
481
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482=head2 New C APIs
483
1e463951 484See L</Internal Changes>.
9378886b 485
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486=head1 Security
487
948b8455 488=head2 User-defined regular expression properties
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489
490In L<perlunicode/"User-Defined Character Properties">, it says you can
491create custom properties by defining subroutines whose names begin with
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492"In" or "Is". However, Perl did not actually enforce that naming
493restriction, so \p{foo::bar} could call foo::bar() if it existed. Now this
494convention has been enforced.
5076a392 495
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496Also, Perl no longer allows a tainted regular expression to invoke a
497user-defined. It simply dies instead [perl #82616].
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498
499=head1 Incompatible Changes
500
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501Perl 5.14.0 is not binary-compatible with any previous stable release.
502
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503In addition to the sections that follow, see L</C API Changes>.
504
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505=head2 Regular Expressions and String Escapes
506
54c7bb16 507=head3 \400-\777
5076a392 508
54c7bb16 509Use of C<\400>-C<\777> in regexes in certain circumstances has given
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510different, anomalous behavior than their use in all other
511double-quote-like contexts. Since 5.10.1, a deprecated warning message
512has been raised when this happens. Now, all double-quote-like contexts
513have the same behavior, namely to be equivalent to C<\x{100}> -
514C<\x{1FF}>, with no deprecation warning. Use of these values in the
515command line option C<"-0"> retains the current meaning to slurp input
516files whole; previously, this was documented only for C<"-0777">. It is
517recommended, however, because of various ambiguities, to use the new
518C<\o{...}> construct to represent characters in octal.
5076a392 519
61752d82 520=head3 Most C<\p{}> properties are now immune to case-insensitive matching
5076a392 521
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522For most Unicode properties, it doesn't make sense to have them match
523differently under C</i> case-insensitive matching than not. And doing
524so leads to unexpected results and potential security holes. For
525example
5076a392 526
61752d82 527 m/\p{ASCII_Hex_Digit}+/i
5076a392 528
61752d82 529could previously match non-ASCII characters because of the Unicode
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530matching rules (although there were a number of bugs with this). Now
531matching under C</i> gives the same results as non-C</i> matching except
532for those few properties where people have come to expect differences,
533namely the ones where casing is an integral part of their meaning, such
534as C<m/\p{Uppercase}/i> and C<m/\p{Lowercase}/i>, both of which match
535the exact same code points, namely those matched by C<m/\p{Cased}/i>.
536Details are in L<perlrecharclass/Unicode Properties>.
5076a392 537
61752d82 538User-defined property handlers that need to match differently under
4cf6a51f 539C</i> must change to read the new boolean parameter passed to them which is
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540non-zero if case-insensitive matching is in effect or 0 otherwise. See
541L<perluniprops/User-Defined Character Properties>.
5076a392 542
61752d82 543=head3 \p{} implies Unicode semantics
5076a392 544
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545Now, a Unicode property match specified in the pattern will indicate
546that the pattern is meant for matching according to Unicode rules, the way
bc15a0a0 547C<\N{}> does.
5076a392 548
61752d82 549=head3 Regular expressions retain their localeness when interpolated
5076a392 550
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551Regular expressions compiled under C<"use locale"> now retain this when
552interpolated into a new regular expression compiled outside a
553C<"use locale">, and vice-versa.
5076a392 554
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555Previously, a regular expression interpolated into another one inherited
556the localeness of the surrounding one, losing whatever state it
557originally had. This is considered a bug fix, but may trip up code that
558has come to rely on the incorrect behavior.
5076a392 559
61752d82 560=head3 Stringification of regexes has changed
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561
562Default regular expression modifiers are now notated by using
563C<(?^...)>. Code relying on the old stringification will fail. The
564purpose of this is so that when new modifiers are added, such code will
565not have to change (after this one time), as the stringification will
566automatically incorporate the new modifiers.
567
568Code that needs to work properly with both old- and new-style regexes
f318e2e6 569can avoid the whole issue by using (for Perls since 5.9.5; see L<re>):
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570
571 use re qw(regexp_pattern);
572 my ($pat, $mods) = regexp_pattern($re_ref);
573
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574If the actual stringification is important, or older Perls need to be
575supported, you can use something like the following:
576
577 # Accept both old and new-style stringification
578 my $modifiers = (qr/foobar/ =~ /\Q(?^/) ? '^' : '-xism';
579
580And then use C<$modifiers> instead of C<-xism>.
581
61752d82 582=head3 Run-time code blocks in regular expressions inherit pragmata
5076a392 583
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584Code blocks in regular expressions (C<(?{...})> and C<(??{...})>) used not
585to inherit any pragmata (strict, warnings, etc.) if the regular expression
586was compiled at run time as happens in cases like these two:
5076a392 587
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588 use re 'eval';
589 $foo =~ $bar; # when $bar contains (?{...})
590 $foo =~ /$bar(?{ $finished = 1 })/;
591
592This was a bug, which has now been fixed. But it has the potential to break
593any code that was relying on it.
5076a392 594
61752d82 595=head2 Stashes and Package Variables
5076a392 596
61752d82 597=head3 Localised tied hashes and arrays are no longed tied
5076a392 598
61752d82 599In the following:
5076a392 600
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601 tie @a, ...;
602 {
603 local @a;
604 # here, @a is a now a new, untied array
605 }
606 # here, @a refers again to the old, tied array
5076a392 607
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608The new local array used to be made tied too, which was fairly pointless,
609and has now been fixed. This fix could however potentially cause a change
610in behaviour of some code.
5076a392 611
61752d82 612=head3 Stashes are now always defined
5076a392 613
61752d82
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614C<defined %Foo::> now always returns true, even when no symbols have yet been
615defined in that package.
5076a392 616
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617This is a side effect of removing a special case kludge in the tokeniser,
618added for 5.10.0, to hide side effects of changes to the internal storage of
619hashes that drastically reduce their memory usage overhead.
620
621Calling defined on a stash has been deprecated since 5.6.0, warned on
622lexicals since 5.6.0, and warned for stashes (and other package
623variables) since 5.12.0. C<defined %hash> has always exposed an
624implementation detail - emptying a hash by deleting all entries from it does
625not make C<defined %hash> false, hence C<defined %hash> is not valid code to
626determine whether an arbitrary hash is empty. Instead, use the behaviour
627that an empty C<%hash> always returns false in a scalar context.
628
629=head3 Dereferencing typeglobs
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630
631If you assign a typeglob to a scalar variable:
632
633 $glob = *foo;
634
635the glob that is copied to C<$glob> is marked with a special flag
636indicating that the glob is just a copy. This allows subsequent assignments
637to C<$glob> to overwrite the glob. The original glob, however, is
638immutable.
639
640Many Perl operators did not distinguish between these two types of globs.
641This would result in strange behaviour in edge cases: C<untie $scalar>
642would do nothing if the last thing assigned to the scalar was a glob
643(because it treated it as C<untie *$scalar>, which unties a handle).
f318e2e6 644Assignment to a glob slot (e.g., C<*$glob = \@some_array>) would simply
5076a392
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645assign C<\@some_array> to C<$glob>.
646
647To fix this, the C<*{}> operator (including the C<*foo> and C<*$foo> forms)
648has been modified to make a new immutable glob if its operand is a glob
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FC
649copy. This allows operators that make a distinction between globs and
650scalars to be modified to treat only immutable globs as globs. (C<tie>,
651C<tied> and C<untie> have been left as they are for compatibility's sake,
61752d82 652but will warn. See L</Deprecations>.)
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653
654This causes an incompatible change in code that assigns a glob to the
655return value of C<*{}> when that operator was passed a glob copy. Take the
656following code, for instance:
657
658 $glob = *foo;
659 *$glob = *bar;
660
661The C<*$glob> on the second line returns a new immutable glob. That new
662glob is made an alias to C<*bar>. Then it is discarded. So the second
663assignment has no effect.
664
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665See L<http://rt.perl.org/rt3/Public/Bug/Display.html?id=77810> for even
666more detail.
667
61752d82 668=head3 Clearing stashes
5076a392
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669
670Stash list assignment C<%foo:: = ()> used to make the stash anonymous
671temporarily while it was being emptied. Consequently, any of its
672subroutines referenced elsewhere would become anonymous (showing up as
673"(unknown)" in C<caller>). Now they retain their package names, such that
674C<caller> will return the original sub name if there is still a reference
675to its typeglob, or "foo::__ANON__" otherwise [perl #79208].
676
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677=head3 Magic variables outside the main package
678
679In previous versions of Perl, magic variables like C<$!>, C<%SIG>, etc. would
680'leak' into other packages. So C<%foo::SIG> could be used to access signals,
681C<${"foo::!"}> (with strict mode off) to access C's C<errno>, etc.
682
683This was a bug, or an 'unintentional' feature, which caused various ill effects,
684such as signal handlers being wiped when modules were loaded, etc.
685
686This has been fixed (or the feature has been removed, depending on how you see
687it).
688
689=head2 Changes to Syntax or to Perl Operators
690
691=head3 C<given> return values
692
693C<given> blocks now return the last evaluated
694expression, or an empty list if the block was exited by C<break>. Thus you
695can now write:
696
697 my $type = do {
698 given ($num) {
699 break when undef;
700 'integer' when /^[+-]?[0-9]+$/;
701 'float' when /^[+-]?[0-9]+(?:\.[0-9]+)?$/;
702 'unknown';
703 }
704 };
705
706See L<perlsyn/Return value> for details.
707
708=head3 Change in the parsing of certain prototypes
709
710Functions declared with the following prototypes now behave correctly as unary
711functions:
712
713 *
714 \$ \% \@ \* \&
715 \[...]
716 ;$ ;*
717 ;\$ ;\% etc.
718 ;\[...]
719
720Due to this bug fix [perl #75904], functions
721using the C<(*)>, C<(;$)> and C<(;*)> prototypes
722are parsed with higher precedence than before. So in the following example:
723
724 sub foo($);
725 foo $a < $b;
726
727the second line is now parsed correctly as C<< foo($a) < $b >>, rather than
728C<< foo($a < $b) >>. This happens when one of these operators is used in
729an unparenthesised argument:
730
731 < > <= >= lt gt le ge
732 == != <=> eq ne cmp ~~
733 &
734 | ^
735 &&
736 || //
737 .. ...
738 ?:
739 = += -= *= etc.
740
741=head3 Smart-matching against array slices
742
743Previously, the following code resulted in a successful match:
744
745 my @a = qw(a y0 z);
746 my @b = qw(a x0 z);
747 @a[0 .. $#b] ~~ @b;
748
749This odd behaviour has now been fixed [perl #77468].
750
751=head3 Negation treats strings differently from before
752
753The unary negation operator C<-> now treats strings that look like numbers
754as numbers [perl #57706].
755
756=head3 Negative zero
757
758Negative zero (-0.0), when converted to a string, now becomes "0" on all
759platforms. It used to become "-0" on some, but "0" on others.
760
761If you still need to determine whether a zero is negative, use
762C<sprintf("%g", $zero) =~ /^-/> or the L<Data::Float> module on CPAN.
763
764=head3 C<:=> is now a syntax error
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765
766Previously C<my $pi := 4;> was exactly equivalent to C<my $pi : = 4;>,
767with the C<:> being treated as the start of an attribute list, ending before
768the C<=>. The use of C<:=> to mean C<: => was deprecated in 5.12.0, and is now
769a syntax error. This will allow the future use of C<:=> as a new token.
770
771We find no Perl 5 code on CPAN using this construction, outside the core's
772tests for it, so we believe that this change will have very little impact on
773real-world codebases.
774
775If it is absolutely necessary to have empty attribute lists (for example,
776because of a code generator) then avoid the error by adding a space before
777the C<=>.
778
61752d82 779=head2 Threads and Processes
5076a392 780
61752d82 781=head3 Directory handles not copied to threads
5076a392 782
61752d82
FC
783On systems other than Windows that do not have
784a C<fchdir> function, newly-created threads no
785longer inherit directory handles from their parent threads. Such programs
786would usually have crashed anyway [perl #75154].
5076a392 787
61752d82 788=head3 C<close> on shared pipes
5076a392 789
61752d82
FC
790The C<close> function no longer waits for the child process to exit if the
791underlying file descriptor is still in use by another thread, to avoid
792deadlocks. It returns true in such cases.
5076a392 793
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FC
794=head3 fork() emulation will not wait for signalled children
795
796On Windows parent processes would not terminate until all forked
797childred had terminated first. However, C<kill('KILL', ...)> is
798inherently unstable on pseudo-processes, and C<kill('TERM', ...)>
799might not get delivered if the child if blocked in a system call.
800
801To avoid the deadlock and still provide a safe mechanism to terminate
802the hosting process, Perl will now no longer wait for children that
803have been sent a SIGTERM signal. It is up to the parent process to
804waitpid() for these children if child clean-up processing must be
805allowed to finish. However, it is also the responsibility of the
806parent then to avoid the deadlock by making sure the child process
807can't be blocked on I/O either.
808
809See L<perlfork> for more information about the fork() emulation on
810Windows.
811
61752d82 812=head2 Configuration
5076a392 813
61752d82 814=head3 Naming fixes in Policy_sh.SH may invalidate Policy.sh
5076a392 815
61752d82
FC
816Several long-standing typos and naming confusions in Policy_sh.SH have
817been fixed, standardizing on the variable names used in config.sh.
5076a392 818
61752d82
FC
819This will change the behavior of Policy.sh if you happen to have been
820accidentally relying on the Policy.sh incorrect behavior.
f318e2e6 821
5a1f7719
FC
822=head3 Perl source code is read in text mode on Windows
823
824Perl scripts used to be read in binary mode on Windows for the benefit
825of the ByteLoader module (which is no longer part of core Perl). This
826had the side effect of breaking various operations on the DATA filehandle,
827including seek()/tell(), and even simply reading from DATA after file handles
828have been flushed by a call to system(), backticks, fork() etc.
829
830The default build options for Windows have been changed to read Perl source
831code on Windows in text mode now. Hopefully ByteLoader will be updated on
832CPAN to automatically handle this situation [perl #28106].
833
5076a392
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834=head1 Deprecations
835
1e463951
FC
836See also L</Deprecated C APIs>.
837
5076a392
FC
838=head2 Omitting a space between a regular expression and subsequent word
839
18139a1b
FC
840Omitting a space between a regular expression operator or
841its modifiers and the following word is deprecated. For
842example, C<< m/foo/sand $bar >> will still be parsed
843as C<< m/foo/s and $bar >> but will issue a warning.
5076a392 844
e683df94
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845=head2 C<\cI<X>>
846
847The backslash-c construct was designed as a way of specifying
848non-printable characters, but there were no restrictions (on ASCII
849platforms) on what the character following the C<c> could be. Now,
850a deprecation warning is raised if that character isn't an ASCII character.
851Also, a deprecation warning is raised for C<"\c{"> (which is the same
852as simply saying C<";">).
853
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854=head2 C<"\b{"> and C<"\B{">
855
856In regular expressions, a literal C<"{"> immediately following a C<"\b">
857(not in a bracketed character class) or a C<"\B{"> is now deprecated
858to allow for its future use by Perl itself.
859
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860=head2 Deprecation warning added for deprecated-in-core .pl libs
861
862This is a mandatory warning, not obeying -X or lexical warning bits.
863The warning is modelled on that supplied by deprecate.pm for
864deprecated-in-core .pm libraries. It points to the specific CPAN
823d0e46
FC
865distribution that contains the .pl libraries. The CPAN version, of
866course, does not generate the warning.
5076a392
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867
868=head2 List assignment to C<$[>
869
823d0e46
FC
870Assignment to C<$[> was deprecated and started to give warnings in
871Perl version 5.12.0. This version of perl also starts to emit a warning when
872assigning to C<$[> in list context. This fixes an oversight in 5.12.0.
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873
874=head2 Use of qw(...) as parentheses
875
876Historically the parser fooled itself into thinking that C<qw(...)> literals
877were always enclosed in parentheses, and as a result you could sometimes omit
878parentheses around them:
879
880 for $x qw(a b c) { ... }
881
882The parser no longer lies to itself in this way. Wrap the list literal in
823d0e46 883parentheses, like this:
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884
885 for $x (qw(a b c)) { ... }
886
887=head2 C<\N{BELL}> is deprecated
888
889This is because Unicode is using that name for a different character.
890See L</Unicode Version 6.0 is now supported (mostly)> for more
891explanation.
892
893=head2 C<?PATTERN?> is deprecated
894
895C<?PATTERN?> (without the initial m) has been deprecated and now produces
896a warning. This is to allow future use of C<?> in new operators.
897The match-once functionality is still available in the form of C<m?PATTERN?>.
898
5076a392
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899=head2 Tie functions on scalars holding typeglobs
900
901Calling a tie function (C<tie>, C<tied>, C<untie>) with a scalar argument
902acts on a file handle if the scalar happens to hold a typeglob.
903
904This is a long-standing bug that will be removed in Perl 5.16, as
905there is currently no way to tie the scalar itself when it holds
906a typeglob, and no way to untie a scalar that has had a typeglob
907assigned to it.
908
823d0e46 909Now there is a deprecation warning whenever a tie
5076a392
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910function is used on a handle without an explicit C<*>.
911
18139a1b 912=head2 User-defined case-mapping
5076a392 913
18139a1b
FC
914This feature is being deprecated due to its many issues, as documented in
915L<perlunicode/User-Defined Case Mappings (for serious hackers only)>.
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916It is planned to remove this feature in Perl 5.16. Instead use the CPAN module
917L<Unicode::Casing>, which provides improved functionality.
823d0e46 918
18139a1b 919=head2 Deprecated modules
5076a392
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920
921The following modules will be removed from the core distribution in a
922future release, and should be installed from CPAN instead. Distributions
923on CPAN which require these should add them to their prerequisites. The
823d0e46 924core versions of these modules will issue a deprecation warning.
5076a392
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925
926If you ship a packaged version of Perl, either alone or as part of a
927larger system, then you should carefully consider the repercussions of
823d0e46 928core module deprecations. You may want to consider shipping your default
5076a392 929build of Perl with packages for some or all deprecated modules which
823d0e46 930install into C<vendor> or C<site> perl library directories. This will
5076a392
FC
931inhibit the deprecation warnings.
932
933Alternatively, you may want to consider patching F<lib/deprecate.pm>
934to provide deprecation warnings specific to your packaging system
935or distribution of Perl, consistent with how your packaging system
936or distribution manages a staged transition from a release where the
937installation of a single package provides the given functionality, to
938a later release where the system administrator needs to know to install
939multiple packages to get that same functionality.
940
941You can silence these deprecation warnings by installing the modules
942in question from CPAN. To install the latest version of all of them,
943just install C<Task::Deprecations::5_14>.
944
945=over
946
947=item L<Devel::DProf>
948
949We strongly recommend that you install and used L<Devel::NYTProf> in
950preference, as it offers significantly improved profiling and reporting.
951
952=back
953
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954=head1 Performance Enhancements
955
54c7bb16 956=head2 "Safe signals" optimisation
df91d470
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957
958Signal dispatch has been moved from the runloop into control ops. This
959should give a few percent speed increase, and eliminates almost all of
960the speed penalty caused by the introduction of "safe signals" in
9615.8.0. Signals should still be dispatched within the same statement as
962they were previously - if this is not the case, or it is possible to
963create uninterruptible loops, this is a bug, and reports are encouraged
964of how to recreate such issues.
965
54c7bb16 966=head2 Optimisation of shift; and pop; calls without arguments
df91d470 967
111b6aa7
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968Two fewer OPs are used for shift and pop calls with no argument (with
969implicit C<@_>). This change makes C<shift;> 5% faster than C<shift @_;>
970on non-threaded perls and 25% faster on threaded.
df91d470 971
fa232254 972=head2 Optimisation of regexp engine string comparison work
df91d470 973
fa232254
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974The foldEQ_utf8 API function for case-insensitive comparison of strings (which
975is used heavily by the regexp engine) was substantially refactored and
976optimised - and its documentation much improved as a free bonus gift.
df91d470 977
fa232254 978=head2 Regular expression compilation speed-up
df91d470 979
fa232254
FC
980Compiling regular expressions has been made faster for the case where upgrading
981the regex to utf8 is necessary but that isn't known when the compilation begins.
df91d470 982
fa232254 983=head2 String appending is 100 times faster
df91d470 984
fa232254
FC
985When doing a lot of string appending, perl could end up allocating a lot more
986memory than needed in a very inefficient way, if perl was configured to use the
987system's C<malloc> implementation instead of its own.
988
989C<sv_grow>, which is what's being used to allocate more memory if necessary
990when appending to a string, has now been taught how to round up the memory
991it requests to a certain geometric progression, making it much faster on
992certain platforms and configurations. On Win32, it's now about 100 times
993faster.
994
995=head2 Eliminate C<PL_*> accessor functions under ithreads
996
997When C<MULTIPLICITY> was first developed, and interpreter state moved into
998an interpreter struct, thread and interpreter local C<PL_*> variables were
999defined as macros that called accessor functions, returning the address of
1000the value, outside of the perl core. The intent was to allow members
1001within the interpreter struct to change size without breaking binary
1002compatibility, so that bug fixes could be merged to a maintenance branch
1003that necessitated such a size change.
1004
1005However, some non-core code defines C<PERL_CORE>, sometimes intentionally
1006to bypass this mechanism for speed reasons, sometimes for other reasons but
1007with the inadvertent side effect of bypassing this mechanism. As some of
1008this code is widespread in production use, the result is that the core
1009I<can't> change the size of members of the interpreter struct, as it will
1010break such modules compiled against a previous release on that maintenance
1011branch. The upshot is that this mechanism is redundant, and well-behaved
1012code is penalised by it. Hence it can and should be removed (and has
1013been).
1014
1015=head2 Freeing weak references
1016
1017When an object has many weak references to it, freeing that object
1018can under some some circumstances take O(N^2) time to free (where N is the
1019number of references). The number of circumstances has been reduced
1020[perl #75254]
1021
1022=head2 Lexical array and hash assignments
1023
1024An earlier optimisation to speed up C<my @array = ...> and
1025C<my %hash = ...> assignments caused a bug and was disabled in Perl 5.12.0.
1026
1027Now we have found another way to speed up these assignments [perl #82110].
df91d470 1028
111b6aa7 1029=head2 C<@_> uses less memory
df91d470 1030
111b6aa7
FC
1031Previously, C<@_> was allocated for every subroutine at compile time with
1032enough space for four entries. Now this allocation is done on demand when
1033the subroutine is called [perl #72416].
5076a392 1034
5076a392
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1035=head2 Size optimisations to SV and HV structures
1036
1037xhv_fill has been eliminated from struct xpvhv, saving 1 IV per hash and
111b6aa7 1038on some systems will cause struct xpvhv to become cache-aligned. To avoid
5076a392
FC
1039this memory saving causing a slowdown elsewhere, boolean use of HvFILL
1040now calls HvTOTALKEYS instead (which is equivalent) - so while the fill
111b6aa7
FC
1041data when actually required are now calculated on demand, the cases when
1042this needs to be done should be few and far between.
5076a392 1043
111b6aa7
FC
1044The order of structure elements in SV bodies has changed. Effectively,
1045the NV slot has swapped location with STASH and MAGIC. As all access to
1046SV members is via macros, this should be completely transparent. This
5076a392
FC
1047change allows the space saving for PVHVs documented above, and may reduce
1048the memory allocation needed for PVIVs on some architectures.
1049
fa232254
FC
1050C<XPV>, C<XPVIV>, and C<XPVNV> now only allocate the parts of the C<SV> body
1051they actually use, saving some space.
5076a392 1052
fa232254
FC
1053Scalars containing regular expressions now only allocate the part of the C<SV>
1054body they actually use, saving some space.
5076a392
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1055
1056=head2 Memory consumption improvements to Exporter
1057
1058The @EXPORT_FAIL AV is no longer created unless required, hence neither is
111b6aa7
FC
1059the typeglob backing it. This saves about 200 bytes for every package that
1060uses Exporter but doesn't use this functionality.
5076a392 1061
111b6aa7 1062=head2 Memory savings for weak references
5076a392
FC
1063
1064For weak references, the common case of just a single weak reference per
1065referent has been optimised to reduce the storage required. In this case it
111b6aa7 1066saves the equivalent of one small Perl array per referent.
5076a392 1067
111b6aa7 1068=head2 C<%+> and C<%-> use less memory
5076a392
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1069
1070The bulk of the C<Tie::Hash::NamedCapture> module used to be in the perl
111b6aa7 1071core. It has now been moved to an XS module, to reduce the overhead for
5076a392
FC
1072programs that do not use C<%+> or C<%->.
1073
fa232254 1074=head2 Multiple small improvements to threads
5076a392 1075
fa232254
FC
1076The internal structures of threading now make fewer API calls and fewer
1077allocations, resulting in noticeably smaller object code. Additionally,
1078many thread context checks have been deferred so that they're only done
1079when required (although this is only possible for non-debugging builds).
5076a392 1080
fa232254 1081=head2 Adjacent pairs of nextstate opcodes are now optimized away
5076a392 1082
fa232254 1083Previously, in code such as
5076a392 1084
fa232254 1085 use constant DEBUG => 0;
5076a392 1086
fa232254
FC
1087 sub GAK {
1088 warn if DEBUG;
1089 print "stuff\n";
1090 }
5076a392 1091
fa232254
FC
1092the ops for C<warn if DEBUG;> would be folded to a C<null> op (C<ex-const>), but
1093the C<nextstate> op would remain, resulting in a runtime op dispatch of
1094C<nextstate>, C<nextstate>, ....
5076a392 1095
fa232254
FC
1096The execution of a sequence of C<nextstate> ops is indistinguishable from just
1097the last C<nextstate> op so the peephole optimizer now eliminates the first of
1098a pair of C<nextstate> ops, except where the first carries a label, since labels
1099must not be eliminated by the optimizer and label usage isn't conclusively known
1100at compile time.
5076a392
FC
1101
1102=head1 Modules and Pragmata
1103
1104=head2 New Modules and Pragmata
1105
1106=over 4
1107
1108=item *
1109
1110C<CPAN::Meta::YAML> 0.003 has been added as a dual-life module. It supports a
1111subset of YAML sufficient for reading and writing META.yml and MYMETA.yml files
1112included with CPAN distributions or generated by the module installation
1113toolchain. It should not be used for any other general YAML parsing or
1114generation task.
1115
1116=item *
1117
1118C<CPAN::Meta> version 2.110440 has been added as a dual-life module. It
1119provides a standard library to read, interpret and write CPAN distribution
1120metadata files (e.g. META.json and META.yml) which describes a
1121distribution, its contents, and the requirements for building it and
1122installing it. The latest CPAN distribution metadata specification is
1123included as C<CPAN::Meta::Spec> and notes on changes in the specification
1124over time are given in C<CPAN::Meta::History>.
1125
1126=item *
1127
5a553547 1128C<HTTP::Tiny> 0.011 has been added as a dual-life module. It is a very
5076a392
FC
1129small, simple HTTP/1.1 client designed for simple GET requests and file
1130mirroring. It has has been added to enable CPAN.pm and CPANPLUS to
1131"bootstrap" HTTP access to CPAN using pure Perl without relying on external
1132binaries like F<curl> or F<wget>.
1133
1134=item *
1135
1136C<JSON::PP> 2.27105 has been added as a dual-life module, for the sake of
1137reading F<META.json> files in CPAN distributions.
1138
1139=item *
1140
21ef4e45 1141C<Module::Metadata> 1.000004 has been added as a dual-life module. It gathers
5076a392
FC
1142package and POD information from Perl module files. It is a standalone module
1143based on Module::Build::ModuleInfo for use by other module installation
1144toolchain components. Module::Build::ModuleInfo has been deprecated in
1145favor of this module instead.
1146
1147=item *
1148
1149C<Perl::OSType> 1.002 has been added as a dual-life module. It maps Perl
1150operating system names (e.g. 'dragonfly' or 'MSWin32') to more generic types
1151with standardized names (e.g. "Unix" or "Windows"). It has been refactored
1152out of Module::Build and ExtUtils::CBuilder and consolidates such mappings into
1153a single location for easier maintenance.
1154
1155=item *
1156
1157The following modules were added by the C<Unicode::Collate>
1158upgrade. See below for details.
1159
1160C<Unicode::Collate::CJK::Big5>
1161
1162C<Unicode::Collate::CJK::GB2312>
1163
1164C<Unicode::Collate::CJK::JISX0208>
1165
1166C<Unicode::Collate::CJK::Korean>
1167
1168C<Unicode::Collate::CJK::Pinyin>
1169
1170C<Unicode::Collate::CJK::Stroke>
1171
1172=item *
1173
1174C<Version::Requirements> version 0.101020 has been added as a dual-life
1175module. It provides a standard library to model and manipulates module
1176prerequisites and version constraints as defined in the L<CPAN::Meta::Spec>.
1177
1178=back
1179
a5794e94 1180=head2 Updated Modules and Pragma
5076a392
FC
1181
1182=over 4
1183
1184=item *
1185
5076a392
FC
1186C<Archive::Extract> has been upgraded from version 0.38 to 0.48.
1187
1188Updates since 0.38 include: a safe print method that guards
1189Archive::Extract from changes to $\; a fix to the tests when run in core
1984204c
FC
1190perl; support for TZ files; a modification for the lzma
1191logic to favour IO::Uncompress::Unlzma; and a fix
1192for an issue with NetBSD-current and its new unzip
5076a392
FC
1193executable.
1194
1195=item *
1196
1197C<Archive::Tar> has been upgraded from version 1.54 to 1.76.
1198
1984204c
FC
1199Important changes since 1.54 include the following:
1200
1201=over
1202
1203=item *
1204
1205Compatibility with busybox implementations of tar
1206
1207=item *
1208
1209A fix so that C<write()> and C<create_archive()>
1210close only handles they opened
1211
1212=item *
1213
1214A bug was fixed regarding the exit code of extract_archive.
5076a392 1215
1984204c
FC
1216=item *
1217
4f978a3b 1218The C<ptar> utility has a new option to allow safe
5076a392
FC
1219creation of tarballs without world-writable files on Windows, allowing those
1220archives to be uploaded to CPAN.
1221
1984204c
FC
1222=item *
1223
1224A new ptargrep utility for using regular expressions against
5076a392
FC
1225the contents of files in a tar archive.
1226
1984204c
FC
1227=item *
1228
1229Pax extended headers are now skipped.
1230
1231=back
5076a392
FC
1232
1233=item *
1234
5076a392
FC
1235C<B> has been upgraded from version 1.23 to 1.27.
1236
1237It no longer crashes when taking apart a C<y///> containing characters
1238outside the octet range or compiled in a C<use utf8> scope.
1239
1240The size of the shared object has been reduced by about 40%, with no
1241reduction in functionality.
1242
1243=item *
1244
1245C<B::Concise> has been upgraded from version 0.78 to 0.82.
1246
1247B::Concise marks rv2sv, rv2av and rv2hv ops with the new OPpDEREF flag
1248as "DREFed".
1249
1250It no longer produces mangled output with the C<-tree> option
1251[perl #80632].
1252
1253=item *
1254
c67a4e29 1255C<B::Deparse> has been upgraded from version 0.96 to 1.03.
5076a392 1256
1984204c 1257The deparsing of a nextstate op has changed when it has both a
5076a392
FC
1258change of package (relative to the previous nextstate), or a change of
1259C<%^H> or other state, and a label. Previously the label was emitted
cdc10f43 1260first, but now the label is emitted last (5.12.1).
5076a392 1261
5a553547
FC
1262The C<no 5.13.2> or similar form is now correctly handled by B::Deparse
1263(5.12.3).
5076a392
FC
1264
1265B::Deparse now properly handles the code that applies a conditional
1266pattern match against implicit C<$_> as it was fixed in [perl #20444].
1267
1984204c
FC
1268Deparsing of C<our> followed by a variable with funny characters
1269(as permitted under the C<utf8> pragma) has also been fixed [perl #33752].
5076a392
FC
1270
1271=item *
1272
c74c1fa8 1273C<Carp> has been upgraded from version 1.15 to 1.20.
5076a392
FC
1274
1275L<Carp> now detects incomplete L<caller()|perlfunc/"caller EXPR"> overrides and
d430b8e7
FC
1276avoids using bogus C<@DB::args>. To provide backtraces,
1277Carp relies on particular behaviour of the C<caller>
1278built-in. Carp now detects if other code has
5076a392 1279overridden this with an incomplete implementation, and modifies its backtrace
d430b8e7
FC
1280accordingly. Previously incomplete overrides would cause incorrect values
1281in backtraces (best case), or obscure fatal errors (worst case).
5076a392
FC
1282
1283This fixes certain cases of C<Bizarre copy of ARRAY> caused by modules
d430b8e7 1284overriding C<caller()> incorrectly (5.12.2).
5076a392 1285
1984204c 1286It now also avoids using regular expressions that cause perl to
5076a392
FC
1287load its Unicode tables, in order to avoid the 'BEGIN not safe after
1288errors' error that will ensue if there has been a syntax error
1289[perl #82854].
1290
1291=item *
1292
9eb7ad55 1293C<CGI> has been upgraded from version 3.48 to 3.52.
5076a392
FC
1294
1295This provides the following security fixes: the MIME boundary in
1984204c
FC
1296multipart_init is now random and the handling of
1297newlines embedded in header values has been improved.
5076a392
FC
1298
1299=item *
1300
5076a392
FC
1301C<Compress::Raw::Bzip2> has been upgraded from version 2.024 to 2.033.
1302
1984204c 1303It has been updated to use bzip2 1.0.6.
5076a392
FC
1304
1305=item *
1306
51090521
FR
1307C<Compress::Raw::Zlib> has been upgraded from version 2.024 to 2.033.
1308
1309=item *
1310
f75b7efc 1311C<CPAN> has been upgraded from version 1.94_56 to 1.9600.
1984204c
FC
1312
1313Major highlights:
5076a392
FC
1314
1315=over 4
1316
1984204c 1317=item * much less configuration dialog hassle
5076a392 1318
1984204c 1319=item * support for META/MYMETA.json
5076a392 1320
1984204c 1321=item * support for local::lib
5076a392 1322
1984204c 1323=item * support for HTTP::Tiny to reduce the dependency on ftp sites
5076a392 1324
1984204c 1325=item * automatic mirror selection
5076a392 1326
1984204c 1327=item * iron out all known bugs in configure_requires
5076a392 1328
1984204c
FC
1329=item * support for distributions compressed with bzip2
1330
1331=item * allow Foo/Bar.pm on the commandline to mean Foo::Bar
1332
1333=back
5076a392
FC
1334
1335=item *
1336
d430b8e7
FC
1337C<CPANPLUS> has been upgraded from version 0.90 to 0.9103.
1338
1339A change to F<cpanp-run-perl>
1340resolves L<RT #55964|http://rt.cpan.org/Public/Bug/Display.html?id=55964>
1341and L<RT #57106|http://rt.cpan.org/Public/Bug/Display.html?id=57106>, both
1342of which related to failures to install distributions that use
1343C<Module::Install::DSL> (5.12.2).
5076a392 1344
1984204c
FC
1345A dependency on Config was not recognised as a
1346core module dependency. This has been fixed.
5076a392 1347
1984204c 1348CPANPLUS now includes support for META.json and MYMETA.json.
5076a392
FC
1349
1350=item *
1351
4467e8f7
FR
1352C<CPANPLUS::Dist::Build> has been upgraded from version 0.46 to 0.54.
1353
1354=item *
1355
5076a392
FC
1356C<Data::Dumper> has been upgraded from version 2.125 to 2.130_02.
1357
4ed2cea4
FC
1358The indentation used to be off when C<$Data::Dumper::Terse> was set. This
1359has been fixed [perl #73604].
1360
1984204c
FC
1361This upgrade also fixes a crash when using custom sort functions that might
1362cause the stack to change [perl #74170].
5076a392
FC
1363
1364C<Dumpxs> no longer crashes with globs returned by C<*$io_ref>
1365[perl #72332].
1366
1367=item *
1368
549d34f5
FR
1369C<DB_File> has been upgraded from version 1.820 to 1.821.
1370
1371=item *
1372
5076a392
FC
1373C<Devel::DProf> has been upgraded from version 20080331.00 to 20110228.00.
1374
1375Merely loading C<Devel::DProf> now no longer triggers profiling to start.
1376C<use Devel::DProf> and C<perl -d:DProf ...> still behave as before and start
1377the profiler.
1378
1379NOTE: C<Devel::DProf> is deprecated and will be removed from a future
1984204c 1380version of Perl. We strongly recommend that you install and use
5076a392
FC
1381L<Devel::NYTProf> instead, as it offers significantly improved
1382profiling and reporting.
1383
1384=item *
1385
66899ca3
FR
1386C<Devel::SelfStubber> has been upgraded from version 1.03 to 1.05.
1387
1388=item *
1389
5076a392
FC
1390C<diagnostics> has been upgraded from version 1.19 to 1.22.
1391
1392It now renders pod links slightly better, and has been taught to find
1393descriptions for messages that share their descriptions with other
1394messages.
1395
1396=item *
1397
1398C<Digest::MD5> has been upgraded from version 2.39 to 2.51.
1399
1400It is now safe to use this module in combination with threads.
1401
1402=item *
1403
1404C<Digest::SHA> has been upgraded from version 5.47 to 5.61.
1405
1406C<shasum> now more closely mimics C<sha1sum>/C<md5sum>.
1407
1408C<Addfile> accepts all POSIX filenames.
1409
1984204c
FC
1410New SHA-512/224 and SHA-512/256 transforms (ref. NIST Draft FIPS 180-4
1411[February 2011])
5076a392
FC
1412
1413=item *
1414
e53cbaa3
FR
1415C<Dumpvalue> has been upgraded from version 1.13 to 1.16.
1416
1417=item *
1418
31e8b85a 1419C<DynaLoader> has been upgraded from version 1.10 to 1.13.
5076a392
FC
1420
1421It fixes a buffer overflow when passed a very long file name.
1422
1423It no longer inherits from AutoLoader; hence it no longer
1424produces weird error messages for unsuccessful method calls on classes that
1425inherit from DynaLoader [perl #84358].
1426
1427=item *
1428
1429C<Encode> has been upgraded from version 2.39 to 2.42.
1430
1431Now, all 66 Unicode non-characters are treated the same way U+FFFF has
1984204c
FC
1432always been treated; in cases when it was disallowed, all 66 are
1433disallowed; in those cases where it warned, all 66 warn.
5076a392
FC
1434
1435=item *
1436
68f90ac3
FR
1437C<Env> has been upgraded from version 1.01 to 1.02.
1438
1439=item *
1440
5076a392
FC
1441C<Errno> has been upgraded from version 1.11 to 1.13.
1442
1443The implementation of C<Errno> has been refactored to use about 55% less memory.
5076a392
FC
1444
1445On some platforms with unusual header files, like Win32/gcc using mingw64
1446headers, some constants which weren't actually error numbers have been exposed
1447by C<Errno>. This has been fixed [perl #77416].
1448
1449=item *
1450
1451C<Exporter> has been upgraded from version 5.64_01 to 5.64_03.
1452
1453Exporter no longer overrides C<$SIG{__WARN__}> [perl #74472]
1454
1455=item *
1456
25fe7f8f
FR
1457C<ExtUtils::CBuilder> has been upgraded from version 0.27 to 0.280202.
1458
1459=item *
1460
2292e71e
FR
1461C<ExtUtils::Command> has been upgraded from version 1.16 to 1.17.
1462
1463=item *
1464
5076a392
FC
1465C<ExtUtils::Constant> has been upgraded from 0.22 to 0.23.
1466
1467The C<AUTOLOAD> helper code generated by C<ExtUtils::Constant::ProxySubs>
1468can now C<croak> for missing constants, or generate a complete C<AUTOLOAD>
1984204c
FC
1469subroutine in XS, allowing simplification of many modules that use it
1470(C<Fcntl>, C<File::Glob>, C<GDBM_File>, C<I18N::Langinfo>, C<POSIX>,
1471C<Socket>).
5076a392
FC
1472
1473C<ExtUtils::Constant::ProxySubs> can now optionally push the names of all
1984204c 1474constants onto the package's C<@EXPORT_OK>.
5076a392
FC
1475
1476=item *
1477
588c5853
FR
1478C<ExtUtils::Install> has been upgraded from version 1.55 to 1.56.
1479
1480=item *
1481
5418ffb3
FR
1482C<ExtUtils::MakeMaker> has been upgraded from version 6.56 to 6.57_05.
1483
1484=item *
1485
f40ab45f
FR
1486C<ExtUtils::Manifest> has been upgraded from version 1.57 to 1.58.
1487
1488=item *
1489
b7064dd7
FR
1490C<ExtUtils::ParseXS> has been upgraded from version 2.21 to 2.2209.
1491
1492=item *
1493
05102622
FR
1494C<File::CheckTree> has been upgraded from version 4.4 to 4.41.
1495
1496=item *
1497
e12786fa 1498C<File::DosGlob> has been upgraded from version 1.01 to 1.04.
5076a392
FC
1499
1500It allows patterns containing literal parentheses (they no longer need to
1984204c
FC
1501be escaped). On Windows, it no longer
1502adds an extra F<./> to the file names
5076a392
FC
1503returned when the pattern is a relative glob with a drive specification,
1504like F<c:*.pl> [perl #71712].
1505
1506=item *
1507
1508C<File::Fetch> has been upgraded from version 0.24 to 0.32.
1509
1510C<HTTP::Lite> is now supported for 'http' scheme.
1511
1512The C<fetch> utility is supported on FreeBSD, NetBSD and
1513Dragonfly BSD for the C<http> and C<ftp> schemes.
1514
1515=item *
1516
23f2cbb1 1517C<File::Find> has been upgraded from version 1.15 to 1.19.
5076a392 1518
1984204c 1519It improves handling of backslashes on Windows, so that paths like
5076a392
FC
1520F<c:\dir\/file> are no longer generated [perl #71710].
1521
1522=item *
1523
d430b8e7
FC
1524C<File::Spec> has been upgraded from version 3.31 to 3.33.
1525
1526Several portability fixes were made in C<File::Spec::VMS>: a colon is now
1527recognized as a delimiter in native filespecs; caret-escaped delimiters are
1528recognized for better handling of extended filespecs; C<catpath()> returns
1529an empty directory rather than the current directory if the input directory
1530name is empty; C<abs2rel()> properly handles Unix-style input (5.12.2).
1531
1532=item *
1533
46ba0657 1534C<File::stat> has been upgraded from 1.02 to 1.05.
5076a392
FC
1535
1536The C<-x> and C<-X> file test operators now work correctly under the root
1537user.
1538
1539=item *
1540
b7edcc3c
FR
1541C<Filter::Simple> has been upgraded from version 0.84 to 0.86.
1542
1543=item *
1544
dc6857fd 1545C<GDBM_File> has been upgraded from 1.10 to 1.14.
5076a392
FC
1546
1547This fixes a memory leak when DBM filters are used.
1548
1549=item *
1550
6e107b45 1551C<Hash::Util> has been upgraded from 0.07 to 0.11.
5076a392 1552
1984204c
FC
1553Hash::Util no longer emits spurious "uninitialized" warnings when
1554recursively locking hashes that have undefined values [perl #74280].
5076a392
FC
1555
1556=item *
1557
eec33fe6
FR
1558C<I18N::Collate> has been upgraded from version 1.01 to 1.02.
1559
1560=item *
1561
ad5f8f47 1562C<I18N::Langinfo> has been upgraded from version 0.03 to 0.08.
5076a392
FC
1563
1564C<langinfo()> now defaults to using C<$_> if there is no argument given, just
5334145a 1565as the documentation has always claimed.
5076a392
FC
1566
1567=item *
1568
c41635f7
FR
1569C<I18N::LangTags> has been upgraded from version 0.35 to 0.35_01.
1570
1571=item *
1572
98a6a4ff
FR
1573C<if> has been upgraded from version 0.05 to 0.0601.
1574
1575=item *
1576
f6ff7fb6
FR
1577C<IO> has been upgraded from version 1.25_02 to 1.25_04.
1578
1579=item *
1580
d13528c5 1581C<IO::Select> has been upgraded from version 1.17 to 1.20.
5076a392
FC
1582
1583It now allows IO::Handle objects (and objects in derived classes) to be
1584removed from an IO::Select set even if the underlying file descriptor is
1585closed or invalid.
1586
1587=item *
1588
d07561d3 1589C<IPC::Cmd> has been upgraded from version 0.54 to 0.70.
5076a392 1590
1984204c
FC
1591Resolves an issue with splitting Win32 command lines. An argument
1592consisting of the single character "0" used to be omitted (CPAN RT #62961).
5076a392
FC
1593
1594=item *
1595
3f16e4eb 1596C<IPC::Open3> has been upgraded from 1.05 to 1.09.
5076a392 1597
4ed2cea4
FC
1598C<open3> now produces an error if the C<exec> call fails, allowing this
1599condition to be distinguished from a child process that exited with a
1600non-zero status [perl #72016].
1601
5076a392
FC
1602The internal C<xclose> routine now knows how to handle file descriptors, as
1603documented, so duplicating STDIN in a child process using its file
1604descriptor now works [perl #76474].
1605
1606=item *
1607
c8b41807
FR
1608C<IPC::SysV> has been upgraded from version 2.01 to 2.03.
1609
1610=item *
1611
ef79f038
FR
1612C<lib> has been upgraded from version 0.62 to 0.63.
1613
1614=item *
1615
5b1884f4 1616C<Locale::Maketext> has been upgraded from version 1.14 to 1.19.
5076a392 1617
1984204c 1618Locale::Maketext now supports external caches.
5076a392 1619
1984204c
FC
1620This upgrade also fixes an infinite loop in
1621C<Locale::Maketext::Guts::_compile()> when
5076a392
FC
1622working with tainted values (CPAN RT #40727).
1623
1984204c 1624C<< ->maketext >> calls will now back up and restore C<$@> so that error
5076a392
FC
1625messages are not suppressed (CPAN RT #34182).
1626
1627=item *
1628
3811bd2b
FR
1629C<Log::Message> has been upgraded from version 0.02 to 0.04.
1630
1631=item *
1632
8eb65377
FR
1633C<Log::Message::Simple> has been upgraded from version 0.06 to 0.08.
1634
1635=item *
1636
5076a392
FC
1637C<Math::BigInt> has been upgraded from version 1.89_01 to 1.994.
1638
1639This fixes, among other things, incorrect results when computing binomial
1640coefficients [perl #77640].
1641
1984204c 1642It also prevents C<sqrt($int)> from crashing under C<use bigrat;>
5076a392
FC
1643[perl #73534].
1644
1645=item *
1646
846c1cec
FR
1647C<Math::BigInt::FastCalc> has been upgraded from version 0.19 to 0.28.
1648
1649=item *
1650
fce4aef3
FR
1651C<Math::BigRat> has been upgraded from version 0.24 to 0.26_02.
1652
1653=item *
1654
12e26027
FR
1655C<Memoize> has been upgraded from version 1.01_03 to 1.02.
1656
1657=item *
1658
5076a392
FC
1659C<MIME::Base64> has been upgraded from 3.08 to 3.13.
1660
1661Includes new functions to calculate the length of encoded and decoded
1662base64 strings.
1663
1664Now provides C<encode_base64url> and C<decode_base64url> functions to process
1665the base64 scheme for "URL applications".
1666
1667=item *
1668
1669C<Module::Build> has been upgraded from version 0.3603 to 0.3800.
1670
1671A notable change is the deprecation of several modules.
1672Module::Build::Version has been deprecated and Module::Build now relies
1673directly upon L<version>. Module::Build::ModuleInfo has been deprecated in
1674favor of a standalone copy of it called L<Module::Metadata>.
1675Module::Build::YAML has been deprecated in favor of L<CPAN::Meta::YAML>.
1676
1677Module::Build now also generates META.json and MYMETA.json files
1678in accordance with version 2 of the CPAN distribution metadata specification,
1679L<CPAN::Meta::Spec>. The older format META.yml and MYMETA.yml files are
1680still generated, as well.
1681
1682=item *
1683
7259fe26 1684C<Module::CoreList> has been upgraded from version 2.29 to 2.47.
5076a392
FC
1685
1686Besides listing the updated core modules of this release, it also stops listing
1984204c 1687the C<Filespec> module. That module never existed in core. The scripts
5076a392 1688generating C<Module::CoreList> confused it with C<VMS::Filespec>, which actually
1984204c 1689is a core module as of perl 5.8.7.
5076a392
FC
1690
1691=item *
1692
193af05b
FR
1693C<Module::Load> has been upgraded from version 0.16 to 0.18.
1694
1695=item *
1696
5b3a054f
FR
1697C<Module::Load::Conditional> has been upgraded from version 0.34 to 0.44.
1698
1699=item *
1700
4f978a3b
FR
1701C<NDBM_File> has been upgraded from version 1.08 to 1.11.
1702
1703This fixes a memory leak when DBM filters are used.
1704
1705=item *
1706
d0aa5c91
FR
1707C<Net::Ping> has been upgraded from version 2.36 to 2.38.
1708
1709=item *
1710
d44b8a8c
FR
1711C<NEXT> has been upgraded from version 0.64 to 0.65.
1712
1713=item *
1714
678d4fd4
FR
1715C<Object::Accessor> has been upgraded from version 0.36 to 0.38.
1716
1717=item *
1718
34188656 1719C<ODBM_File> have been upgraded from version 1.07 to 1.10.
5076a392
FC
1720
1721This fixes a memory leak when DBM filters are used.
1722
1723=item *
1724
77be713d 1725C<overload> has been upgraded from 1.10 to 1.12.
5076a392
FC
1726
1727C<overload::Method> can now handle subroutines that are themselves blessed
1728into overloaded classes [perl #71998].
1729
5076a392
FC
1730The documentation has greatly improved. See L</Documentation> below.
1731
1732=item *
1733
f84c796e
FR
1734C<Params::Check> has been upgraded from version 0.26 to 0.28.
1735
1736=item *
1737
550ee92b
FR
1738C<parent> has been upgraded from version 0.223 to 0.225.
1739
1740=item *
1741
5076a392
FC
1742C<Parse::CPAN::Meta> has been upgraded from version 1.40 to 1.4401.
1743
1984204c 1744The latest Parse::CPAN::Meta can now read YAML and JSON files using
5076a392
FC
1745L<CPAN::Meta::YAML> and L<JSON::PP>, which are now part of the Perl core.
1746
1747=item *
1748
5076a392
FC
1749C<PerlIO::scalar> has been upgraded from 0.07 to 0.11.
1750
1751A C<read> after a C<seek> beyond the end of the string no longer thinks it
1752has data to read [perl #78716].
1753
1754=item *
1755
be3c8498
FR
1756C<Pod::LaTeX> has been upgraded from version 0.58 to 0.59.
1757
1758=item *
1759
fd8a2e89
FR
1760C<Pod::Perldoc> has been upgraded from version 3.15_02 to 3.15_03.
1761
1762=item *
1763
5bcb6583
FR
1764C<Pod::Simple> has been upgraded from version 3.13 to 3.16.
1765
1766=item *
1767
abb8c779 1768C<POSIX> has been upgraded from 1.19 to 1.24.
5076a392
FC
1769
1770It now includes constants for POSIX signal constants.
1771
1772=item *
1773
1984204c 1774C<re> has been upgraded from version 0.11 to 0.17.
5076a392
FC
1775
1776New C<use re "/flags"> pragma
1777
5076a392 1778The C<regmust> function used to crash when called on a regular expression
1984204c 1779belonging to a pluggable engine. Now it croaks instead.
5076a392
FC
1780
1781C<regmust> no longer leaks memory.
1782
1783=item *
1784
1785C<Safe> has been upgraded from version 2.25 to 2.29.
1786
cdc10f43
FC
1787Coderefs returned by C<reval()> and C<rdo()> are now wrapped via
1788C<wrap_code_refs> (5.12.1).
1789
5076a392
FC
1790This fixes a possible infinite loop when looking for coderefs.
1791
cdc10f43 1792It adds several version::vxs::* routines to the default share.
5076a392
FC
1793
1794=item *
1795
5076a392
FC
1796C<SelfLoader> has been upgraded from 1.17 to 1.18.
1797
1798It now works in taint mode [perl #72062].
1799
1800=item *
1801
1802C<sigtrap> has been upgraded from version 1.04 to 1.05.
1803
1804It no longer tries to modify read-only arguments when generating a
1805backtrace [perl #72340].
1806
1807=item *
1808
1984204c 1809C<Socket> has been upgraded from version 1.87 to 1.94.
5076a392 1810
1984204c 1811See L</IPv6 support>, above.
5076a392
FC
1812
1813=item *
1814
1815C<Storable> has been upgraded from version 2.22 to 2.27.
1816
1817Includes performance improvement for overloaded classes.
1818
5076a392 1819This adds support for serialising code references that contain UTF-8 strings
1984204c
FC
1820correctly. The Storable minor version
1821number changed as a result, meaning that
5076a392
FC
1822Storable users who set C<$Storable::accept_future_minor> to a C<FALSE> value
1823will see errors (see L<Storable/FORWARD COMPATIBILITY> for more details).
1824
1825Freezing no longer gets confused if the Perl stack gets reallocated
1826during freezing [perl #80074].
1827
1828=item *
1829
90c6e78f
FR
1830C<Term::ANSIColor> has been upgraded from version 2.02 to 3.00.
1831
1832=item *
1833
d9f2f059
FR
1834C<Term::UI> has been upgraded from version 0.20 to 0.26.
1835
1836=item *
1837
80ebb519
FR
1838C<Test::Harness> has been upgraded from version 3.17 to 3.23.
1839
1840=item *
1841
5076a392
FC
1842C<Test::Simple> has been upgraded from version 0.94 to 0.98.
1843
1844Among many other things, subtests without a C<plan> or C<no_plan> now have an
1845implicit C<done_testing()> added to them.
1846
1847=item *
1848
5076a392
FC
1849C<Thread::Semaphore> has been upgraded from version 2.09 to 2.12.
1850
1984204c
FC
1851It provides two new methods that give more control over the decrementing of
1852semaphores: C<down_nb> and C<down_force>.
5076a392
FC
1853
1854=item *
1855
f0d895e1
FR
1856C<Thread::Queue> has been upgraded from version 2.11 to 2.12.
1857
1858=item *
1859
1a6b954e
FR
1860C<threads> has been upgraded from version 1.75 to 1.83.
1861
1862=item *
1863
55816daa
FR
1864C<threads::shared> has been upgraded from version 1.32 to 1.36.
1865
1866=item *
1867
5076a392
FC
1868C<Tie::Hash> has been upgraded from version 1.03 to 1.04.
1869
1870Calling C<< Tie::Hash-E<gt>TIEHASH() >> used to loop forever. Now it C<croak>s.
1871
1872=item *
1873
ed68b07e
FR
1874C<Tie::RefHash> has been upgraded from version 1.38 to 1.39.
1875
1876=item *
1877
bb3c221a
FR
1878C<Time::HiRes> has been upgraded from version 1.9719 to 1.9721_01.
1879
1880=item *
1881
97fa568b
FR
1882C<Time::Local> has been upgraded from version 1.1901_01 to 1.2000.
1883
1884=item *
1885
a83cb732
FR
1886C<Time::Piece> has been upgraded from version 1.15_01 to 1.20_01.
1887
1888=item *
1889
5076a392
FC
1890C<Unicode::Collate> has been upgraded from version 0.52_01 to 0.73.
1891
1984204c 1892Unicode::Collate has been updated to use Unicode 6.0.0.
5076a392 1893
1984204c
FC
1894Unicode::Collate::Locale now supports a plethora of new locales: ar, be,
1895bg, de__phonebook, hu, hy, kk, mk, nso, om, tn, vi, hr, ig, ja, ko, ru, sq,
1896se, sr, to, uk, zh, zh__big5han, zh__gb2312han, zh__pinyin and zh__stroke.
5076a392
FC
1897
1898The following modules have been added:
1899
1900C<Unicode::Collate::CJK::Big5> for C<zh__big5han> which makes
1901tailoring of CJK Unified Ideographs in the order of CLDR's big5han ordering.
1902
1903C<Unicode::Collate::CJK::GB2312> for C<zh__gb2312han> which makes
1904tailoring of CJK Unified Ideographs in the order of CLDR's gb2312han ordering.
1905
1906C<Unicode::Collate::CJK::JISX0208> which makes tailoring of 6355 kanji
1907(CJK Unified Ideographs) in the JIS X 0208 order.
1908
1909C<Unicode::Collate::CJK::Korean> which makes tailoring of CJK Unified Ideographs
1910in the order of CLDR's Korean ordering.
1911
1912C<Unicode::Collate::CJK::Pinyin> for C<zh__pinyin> which makes
1913tailoring of CJK Unified Ideographs in the order of CLDR's pinyin ordering.
1914
1915C<Unicode::Collate::CJK::Stroke> for C<zh__stroke> which makes
1916tailoring of CJK Unified Ideographs in the order of CLDR's stroke ordering.
1917
5076a392
FC
1918This also sees the switch from using the pure-perl version of this
1919module to the XS version.
1920
1921=item *
1922
ec52b54b
FR
1923C<Unicode::Normalize> has been upgraded from version 1.03 to 1.10.
1924
1925=item *
1926
5076a392
FC
1927C<Unicode::UCD> has been upgraded from version 0.27 to 0.32.
1928
1984204c
FC
1929A new function, C<Unicode::UCD::num()>, has been added. This function
1930returns the numeric value of the string passed it or C<undef> if the string
1931in its entirety has no "safe" numeric value. (For more detail, and for the
1932definition of "safe", see L<Unicode::UCD/num>.)
5076a392 1933
1984204c 1934This upgrade also includes a number of bug fixes:
5076a392
FC
1935
1936=over 4
1937
1938=item charinfo()
1939
1940=over 4
1941
1942=item *
1943
1944It is now updated to Unicode Version 6 with Corrigendum #8, except,
1945as with Perl 5.14, the code point at U+1F514 has no name.
1946
1947=item *
1948
1949The Hangul syllable code points have the correct names, and their
1950decompositions are always output without requiring L<Lingua::KO::Hangul::Util>
1951to be installed.
1952
1953=item *
1954
54c7bb16
FC
1955The CJK (Chinese-Japanese-Korean) code points U+2A700 to U+2B734
1956and U+2B740 to U+2B81D are now properly handled.
5076a392
FC
1957
1958=item *
1959
1960The numeric values are now output for those CJK code points that have them.
1961
1962=item *
1963
1964The names that are output for code points with multiple aliases are now the
1965corrected ones.
1966
1967=back
1968
1969=item charscript()
1970
1971This now correctly returns "Unknown" instead of C<undef> for the script
1972of a code point that hasn't been assigned another one.
1973
1974=item charblock()
1975
1976This now correctly returns "No_Block" instead of C<undef> for the block
1977of a code point that hasn't been assigned to another one.
1978
1979=back
1980
5076a392
FC
1981=item *
1982
1983C<version> has been upgraded from 0.82 to 0.88.
1984
1984204c 1985Due to a bug, now fixed, the C<is_strict> and C<is_lax> functions did not
cdc10f43 1986work when exported (5.12.1).
5076a392
FC
1987
1988=item *
1989
3e625598 1990C<warnings> has been upgraded from version 1.09 to 1.12.
5076a392
FC
1991
1992Calling C<use warnings> without arguments is now significantly more efficient.
1993
4f978a3b
FR
1994=item *
1995
1996C<warnings::register> have been upgraded from version 1.01 to 1.02.
1997
5076a392
FC
1998It is now possible to register warning categories other than the names of
1999packages using C<warnings::register>. See L<perllexwarn> for more information.
2000
2001=item *
2002
62e270c2
FR
2003C<XSLoader> has been upgraded from version 0.10 to 0.13.
2004
2005=item *
2006
5076a392
FC
2007C<VMS::DCLsym> has been upgraded from version 1.03 to 1.05.
2008
2009Two bugs have been fixed [perl #84086]:
2010
2011The symbol table name was lost when tying a hash, due to a thinko in
2012C<TIEHASH>. The result was that all tied hashes interacted with the
2013local symbol table.
2014
2015Unless a symbol table name had been explicitly specified in the call
2016to the constructor, querying the special key ':LOCAL' failed to
2017identify objects connected to the local symbol table.
2018
2019=item *
2020
2021C<Win32> has been upgraded from version 0.39 to 0.44.
2022
1984204c
FC
2023This release has several new functions: C<Win32::GetSystemMetrics>,
2024C<Win32::GetProductInfo>, C<Win32::GetOSDisplayName>.
5076a392 2025
1984204c
FC
2026The names returned by C<Win32::GetOSName> and C<Win32::GetOSDisplayName>
2027have been corrected.
5076a392 2028
5076a392
FC
2029=back
2030
5076a392
FC
2031=head2 Removed Modules and Pragmata
2032
2033The following modules have been removed from the core distribution, and if
2034needed should be installed from CPAN instead.
2035
2036=over
2037
4f978a3b
FR
2038=item *
2039
2040C<Class::ISA> has been removed from the Perl core. Prior version was 0.36.
5076a392 2041
4f978a3b
FR
2042=item *
2043
2044C<Pod::Plainer> has been removed from the Perl core. Prior version was 1.02.
2045
2046=item *
5076a392 2047
4f978a3b 2048C<Switch> has been removed from the Perl core. Prior version was 2.16.
5076a392
FC
2049
2050=back
2051
2052The removal of C<Shell> has been deferred until after 5.14, as the
2053implementation of C<Shell> shipped with 5.12.0 did not correctly issue the
2054warning that it was to be removed from core.
2055
2056=head1 Documentation
2057
5076a392
FC
2058=head2 New Documentation
2059
41e29def 2060=head3 L<perlgpl>
5076a392
FC
2061
2062L<perlgpl> has been updated to contain GPL version 1, as is included in the
cdc10f43 2063F<README> distributed with perl (5.12.1).
5076a392 2064
41e29def 2065=head3 Perl 5.12.x delta files
5076a392 2066
41e29def
FC
2067The perldelta files for Perl 5.12.1 to 5.12.3 have been added from the
2068maintenance branch: L<perl5121delta>, L<perl5122delta>, L<perl5123delta>.
5076a392
FC
2069
2070=head3 L<perlpodstyle>
2071
2072New style guide for POD documentation,
2073split mostly from the NOTES section of the pod2man man page.
2074
41e29def
FC
2075=head3 L<perlsource>, L<perlinterp>, L<perlhacktut>, and L<perlhacktips>
2076
2077See L</L<perlhack> and perlrepository revamp>, below.
5076a392
FC
2078
2079=head2 Changes to Existing Documentation
2080
41e29def 2081=head3 L<perlmodlib> is now complete
4ed2cea4
FC
2082
2083The perlmodlib page that came with Perl 5.12.0 was missing a lot of
2084modules, due to a bug in the script that generates the list. This has been
cdc10f43 2085fixed [perl #74332] (5.12.1).
4ed2cea4 2086
41e29def 2087=head3 Replace wrong tr/// table in L<perlebcdic>
5076a392 2088
41e29def 2089L<perlebcdic> contains a helpful table to use in tr/// to convert
5076a392
FC
2090between EBCDIC and Latin1/ASCII. Unfortunately, the table was the
2091inverse of the one it describes, though the code that used the table
2092worked correctly for the specific example given.
2093
2094The table has been changed to its inverse, and the sample code changed
2095to correspond, as this is easier for the person trying to follow the
2096instructions since deriving the old table is somewhat more complicated.
2097
2098The table has also been changed to hex from octal, as that is more the norm
2099these days, and the recipes in the pod altered to print out leading
41e29def 2100zeros to make all the values the same length.
5076a392 2101
41e29def 2102=head3 Tricks for user-defined casing
5076a392 2103
41e29def
FC
2104L<perlunicode> now contains an explanation of how to override, mangle
2105and otherwise tweak the way perl handles upper-, lower- and other-case
2106conversions on Unicode data, and how to provide scoped changes to alter
2107one's own code's behaviour without stomping on anybody else.
5076a392
FC
2108
2109=head3 INSTALL explicitly states the requirement for C89
2110
d430b8e7
FC
2111This was already true but it's now Officially Stated For The Record
2112(5.12.2).
5076a392 2113
41e29def 2114=head3 Explanation of C<\xI<HH>> and C<\oI<OOO>> escapes
5076a392 2115
41e29def
FC
2116L<perlop> has been updated with more detailed explanation of these two
2117character escapes.
5076a392 2118
41e29def 2119=head3 C<-0I<NNN>> switch
5076a392 2120
41e29def 2121In L<perlrun>, the behavior of the C<-0NNN> switch for C<-0400> or higher
d430b8e7 2122has been clarified (5.12.2).
5076a392 2123
cdc10f43
FC
2124=head3 Maintenance policy
2125
2126L<perlpolicy> now contains the policy on what patches are acceptable for
2127maintenance branches (5.12.1).
2128
41e29def 2129=head3 Deprecation policy
5076a392 2130
41e29def 2131L<perlpolicy> now contains the policy on compatibility and deprecation
d430b8e7 2132along with definitions of terms like "deprecation" (5.12.2).
5076a392 2133
41e29def 2134=head3 New descriptions in L<perldiag>
5076a392
FC
2135
2136The following existing diagnostics are now documented:
2137
2138=over 4
2139
2140=item *
2141
2142L<Ambiguous use of %c resolved as operator %c|perldiag/"Ambiguous use of %c resolved as operator %c">
2143
2144=item *
2145
2146L<Ambiguous use of %c{%s} resolved to %c%s|perldiag/"Ambiguous use of %c{%s} resolved to %c%s">
2147
2148=item *
2149
2150L<Ambiguous use of %c{%s%s} resolved to %c%s%s|perldiag/"Ambiguous use of %c{%s%s} resolved to %c%s%s">
2151
2152=item *
2153
2154L<Ambiguous use of -%s resolved as -&%s()|perldiag/"Ambiguous use of -%s resolved as -&%s()">
2155
2156=item *
2157
2158L<Invalid strict version format (%s)|perldiag/"Invalid strict version format (%s)">
2159
2160=item *
2161
2162L<Invalid version format (%s)|perldiag/"Invalid version format (%s)">
2163
2164=item *
2165
2166L<Invalid version object|perldiag/"Invalid version object">
2167
2168=back
2169
5076a392
FC
2170=head3 L<perlbook>
2171
41e29def 2172L<perlbook> has been expanded to cover many more popular books.
5076a392 2173
41e29def 2174=head3 C<SvTRUE> macro
5076a392 2175
41e29def
FC
2176The documentation for the C<SvTRUE> macro in
2177L<perlapi> was simply wrong in stating that
5076a392
FC
2178get-magic is not processed. It has been corrected.
2179
41e29def 2180=head3 L<perlvar> revamp
5076a392 2181
41e29def 2182L<perlvar> reorders the variables and groups them by topic. Each variable
5076a392 2183introduced after Perl 5.000 notes the first version in which it is
41e29def 2184available. L<perlvar> also has a new section for deprecated variables to
5076a392
FC
2185note when they were removed.
2186
41e29def 2187=head3 Array and hash slices in scalar context
5076a392 2188
41e29def 2189These are now documented in L<perldata>.
5076a392 2190
41e29def 2191=head3 C<use locale> and formats
5076a392
FC
2192
2193L<perlform> and L<perllocale> have been corrected to state that
2194C<use locale> affects formats.
2195
5076a392
FC
2196=head3 L<overload>
2197
5076a392
FC
2198L<overload>'s documentation has practically undergone a rewrite. It
2199is now much more straightforward and clear.
2200
41e29def 2201=head3 L<perlhack> and perlrepository revamp
5076a392
FC
2202
2203The L<perlhack> and perlrepository documents have been heavily edited and
2204split up into several new documents.
2205
2206The L<perlhack> document is now much shorter, and focuses on the Perl 5
2207development process and submitting patches to Perl. The technical content has
2208been moved to several new documents, L<perlsource>, L<perlinterp>,
2209L<perlhacktut>, and L<perlhacktips>. This technical content has only been
2210lightly edited.
2211
2212The perlrepository document has been renamed to L<perlgit>. This new document
2213is just a how-to on using git with the Perl source code. Any other content
2214that used to be in perlrepository has been moved to perlhack.
2215
41e29def 2216=head3 Time::Piece examples
5076a392
FC
2217
2218Examples in L<perlfaq4> have been updated to show the use of
41e29def 2219L<Time::Piece>.
5076a392
FC
2220
2221=head1 Diagnostics
2222
2223The following additions or changes have been made to diagnostic output,
2224including warnings and fatal error messages. For the complete list of
2225diagnostic messages, see L<perldiag>.
2226
2227=head2 New Diagnostics
2228
a593b319
FC
2229=head3 New Errors
2230
5076a392
FC
2231=over
2232
a593b319 2233=item Closure prototype called
5076a392 2234
a593b319
FC
2235This error occurs when a subroutine reference passed to an attribute
2236handler is called, if the subroutine is a closure [perl #68560].
5076a392 2237
a593b319 2238=item Insecure user-defined property %s
5076a392 2239
a593b319
FC
2240Perl detected tainted data when trying to compile a regular
2241expression that contains a call to a user-defined character property
2242function, i.e. C<\p{IsFoo}> or C<\p{InFoo}>.
2243See L<perlunicode/User-Defined Character Properties> and L<perlsec>.
5076a392 2244
a593b319 2245=item panic: gp_free failed to free glob pointer - something is repeatedly re-creating entries
5076a392 2246
a593b319
FC
2247This new error is triggered if a destructor called on an object in a
2248typeglob that is being freed creates a new typeglob entry containing an
2249object with a destructor that creates a new entry containing an object....
5076a392 2250
a593b319 2251=item Parsing code internal error (%s)
5076a392 2252
a593b319
FC
2253This new fatal error is produced when parsing
2254code supplied by an extension violates the
2255parser's API in a detectable way.
5076a392 2256
a593b319 2257=item refcnt: fd %d%s
5076a392 2258
a593b319
FC
2259This new error only occurs if a internal consistency check fails when a
2260pipe is about to be closed.
5076a392 2261
a593b319 2262=item Regexp modifier "/%c" may not appear twice
5076a392 2263
a593b319
FC
2264The regular expression pattern has one of the
2265mutually exclusive modifiers repeated.
5076a392 2266
a593b319 2267=item Regexp modifiers "/%c" and "/%c" are mutually exclusive
5076a392 2268
a593b319
FC
2269The regular expression pattern has more than one of the mutually
2270exclusive modifiers.
5076a392 2271
a593b319 2272=item Using !~ with %s doesn't make sense
5076a392 2273
a593b319 2274This error occurs when C<!~> is used with C<s///r> or C<y///r>.
5076a392 2275
a593b319 2276=back
5076a392 2277
a593b319 2278=head3 New Warnings
5076a392 2279
a593b319 2280=over
5076a392 2281
a593b319 2282=item "\b{" is deprecated; use "\b\{" instead
5076a392 2283
a593b319 2284=item "\B{" is deprecated; use "\B\{" instead
5076a392 2285
a593b319
FC
2286Use of an unescaped "{" immediately following a C<\b> or C<\B> is now
2287deprecated so as to reserve its use for Perl itself in a future release.
5076a392 2288
a593b319 2289=item Operation "%s" returns its argument for ...
5076a392 2290
a593b319
FC
2291Performing an operation requiring Unicode semantics (such as case-folding)
2292on a Unicode surrogate or a non-Unicode character now triggers a warning:
2293'Operation "%s" returns its argument for ...'.
5076a392 2294
a593b319
FC
2295=item Use of qw(...) as parentheses is deprecated
2296
2297See L</"Use of qw(...) as parentheses">, above, for details.
5076a392
FC
2298
2299=back
2300
2301=head2 Changes to Existing Diagnostics
2302
2303=over 4
2304
2305=item *
2306
4ed2cea4
FC
2307The "Variable $foo is not imported" warning that precedes a
2308C<strict 'vars'> error has now been assigned the "misc" category, so that
2309C<no warnings> will suppress it [perl #73712].
2310
2311=item *
2312
5076a392
FC
2313C<warn> and C<die> now produce 'Wide character' warnings when fed a
2314character outside the byte range if STDERR is a byte-sized handle.
2315
2316=item *
2317
2318The 'Layer does not match this perl' error message has been replaced with
a593b319 2319these more helpful messages [perl #73754]:
5076a392
FC
2320
2321=over 4
2322
2323=item *
2324
2325PerlIO layer function table size (%d) does not match size expected by this
2326perl (%d)
2327
2328=item *
2329
2330PerlIO layer instance size (%d) does not match size expected by this perl
2331(%d)
2332
2333=back
2334
5076a392
FC
2335=item *
2336
2337The "Found = in conditional" warning that is emitted when a constant is
2338assigned to a variable in a condition is now withheld if the constant is
2339actually a subroutine or one generated by C<use constant>, since the value
2340of the constant may not be known at the time the program is written
2341[perl #77762].
2342
2343=item *
2344
2345Previously, if none of the C<gethostbyaddr>, C<gethostbyname> and
2346C<gethostent> functions were implemented on a given platform, they would
2347all die with the message 'Unsupported socket function "gethostent" called',
2348with analogous messages for C<getnet*> and C<getserv*>. This has been
2349corrected.
2350
2351=item *
2352
a593b319
FC
2353The warning message about unrecognized regular expression escapes passed
2354through has been changed to include any literal '{' following the
2355two-character escape. E.g., "\q{" is now emitted instead of "\q".
5076a392
FC
2356
2357=back
2358
2359=head1 Utility Changes
2360
0b88cc74 2361=head3 L<perlbug>
5076a392
FC
2362
2363=over 4
2364
2365=item *
2366
0b88cc74
FC
2367L<perlbug> now looks in the EMAIL environment variable for a return address
2368if the REPLY-TO and REPLYTO variables are empty.
5076a392
FC
2369
2370=item *
2371
0b88cc74
FC
2372L<perlbug> did not previously generate a From: header, potentially
2373resulting in dropped mail. Now it does include that header.
5076a392
FC
2374
2375=item *
2376
0b88cc74 2377The user's address is now used as the return-path.
4ed2cea4 2378
0b88cc74
FC
2379Many systems these days don't have a valid Internet domain name and
2380perlbug@perl.org does not accept email with a return-path that does
2381not resolve. So the user's address is now passed to sendmail so it's
2382less likely to get stuck in a mail queue somewhere [perl #82996].
5076a392 2383
2c389f6c
FC
2384=item *
2385
d430b8e7
FC
2386L<perlbug> now always gives the reporter a chance to change the email
2387address it guesses for them (5.12.2).
2388
2389=item *
2390
2391L<perlbug> should no longer warn about uninitialized values when using the C<-d>
2392and C<-v> options (5.12.2).
2c389f6c 2393
5076a392
FC
2394=back
2395
0b88cc74 2396=head3 L<perl5db.pl>
5076a392 2397
0b88cc74 2398=over
5076a392
FC
2399
2400=item *
2401
0b88cc74
FC
2402The remote terminal works after forking and spawns new sessions - one
2403for each forked process.
5076a392
FC
2404
2405=back
2406
0b88cc74 2407=head3 L<ptargrep>
5076a392
FC
2408
2409=over 4
2410
2411=item *
2412
0b88cc74
FC
2413L<ptargrep> is a new utility to apply pattern matching to the contents of
2414files in a tar archive. It comes with C<Archive::Tar>.
5076a392
FC
2415
2416=back
2417
2418=head1 Configuration and Compilation
2419
61752d82
FC
2420See also L</"Naming fixes in Policy_sh.SH may invalidate Policy.sh">,
2421above.
2422
5076a392
FC
2423=over 4
2424
2425=item *
2426
87595b22
FC
2427CCINCDIR and CCLIBDIR for the mingw64
2428cross-compiler are now correctly under
5076a392
FC
2429$(CCHOME)\mingw\include and \lib rather than immediately below $(CCHOME).
2430
5076a392
FC
2431This means the 'incpath', 'libpth', 'ldflags', 'lddlflags' and
2432'ldflags_nolargefiles' values in Config.pm and Config_heavy.pl are now
87595b22 2433set correctly.
5076a392
FC
2434
2435=item *
2436
87595b22
FC
2437'make test.valgrind' has been adjusted to account for cpan/dist/ext
2438separation.
5076a392
FC
2439
2440=item *
2441
2442On compilers that support it, C<-Wwrite-strings> is now added to cflags by
2443default.
2444
2445=item *
2446
2447The C<Encode> module can now (once again) be included in a static Perl
2448build. The special-case handling for this situation got broken in Perl
24495.11.0, and has now been repaired.
2450
1e463951
FC
2451=item *
2452
2453The previous default size of a PerlIO buffer (4096 bytes) has been increased
2454to the larger of 8192 bytes and your local BUFSIZ. Benchmarks show that doubling
2455this decade-old default increases read and write performance in the neighborhood
2456of 25% to 50% when using the default layers of perlio on top of unix. To choose
2457a non-default size, such as to get back the old value or to obtain an even
2458larger value, configure with:
2459
2460 ./Configure -Accflags=-DPERLIOBUF_DEFAULT_BUFSIZ=N
2461
2462where N is the desired size in bytes; it should probably be a multiple of
2463your page size.
2464
d430b8e7
FC
2465=item *
2466
2467An "incompatible operand types" error in ternary expressions when building
2468with C<clang> has been fixed (5.12.2).
2469
2470=item *
2471
2472Perl now skips setuid C<File::Copy> tests on partitions it detects to be mounted
2473as C<nosuid> (5.12.2).
2474
5076a392
FC
2475=back
2476
5076a392
FC
2477=head1 Platform Support
2478
5076a392
FC
2479=head2 New Platforms
2480
5076a392
FC
2481=over 4
2482
2483=item AIX
2484
cdc10f43 2485Perl now builds on AIX 4.2 (5.12.1).
5076a392
FC
2486
2487=back
2488
2489=head2 Discontinued Platforms
2490
2491=over 4
2492
5076a392
FC
2493=item Apollo DomainOS
2494
2495The last vestiges of support for this platform have been excised from the
2496Perl distribution. It was officially discontinued in version 5.12.0. It had
2497not worked for years before that.
2498
2499=item MacOS Classic
2500
2501The last vestiges of support for this platform have been excised from the
2502Perl distribution. It was officially discontinued in an earlier version.
2503
2504=back
2505
2506=head2 Platform-Specific Notes
2507
d430b8e7
FC
2508=head3 AIX
2509
2510=over
2511
2512=item *
2513
2514F<README.aix> has been updated with information about the XL C/C++ V11 compiler
2515suite (5.12.2).
2516
2517=back
2518
2519=head3 ARM
2520
2521=over
2522
2523=item *
2524
2525The C<d_u32align> configuration probe on ARM has been fixed (5.12.2).
2526
2527=back
2528
554003a2 2529=head3 Cygwin
5076a392
FC
2530
2531=over 4
2532
2533=item *
2534
554003a2 2535MakeMaker has been updated to build man pages on cygwin.
5076a392
FC
2536
2537=item *
2538
554003a2
FC
2539Improved rebase behaviour
2540
2541If a dll is updated on cygwin the old imagebase address is reused.
2542This solves most rebase errors, especially when updating on core dll's.
2543See L<http://www.tishler.net/jason/software/rebase/rebase-2.4.2.README> for more information.
5076a392
FC
2544
2545=item *
2546
554003a2 2547Support for the standard cygwin dll prefix, which is e.g. needed for FFI's
5076a392
FC
2548
2549=item *
2550
554003a2 2551Updated build hints file
5076a392
FC
2552
2553=back
2554
cdc10f43
FC
2555=head3 FreeBSD 7
2556
2557=over
2558
2559=item *
2560
2561FreeBSD 7 no longer contains F</usr/bin/objformat>. At build time,
2562Perl now skips the F<objformat> check for versions 7 and higher and
2563assumes ELF (5.12.1).
2564
2565=back
2566
2567=head3 HP-UX
2568
2569=over
2570
2571=item *
2572
2573Perl now allows -Duse64bitint without promoting to use64bitall on HP-UX
2574(5.12.1).
2575
2576=back
2577
554003a2 2578=head3 IRIX
5076a392
FC
2579
2580Conversion of strings to floating-point numbers is now more accurate on
2581IRIX systems [perl #32380].
2582
554003a2 2583=head3 Mac OS X
5076a392
FC
2584
2585Early versions of Mac OS X (Darwin) had buggy implementations of the
2586C<setregid>, C<setreuid>, C<setrgid> and C<setruid> functions, so perl
2587would pretend they did not exist.
2588
2589These functions are now recognised on Mac OS 10.5 (Leopard; Darwin 9) and
2590higher, as they have been fixed [perl #72990].
2591
554003a2 2592=head3 MirBSD
5076a392 2593
554003a2
FC
2594Previously if you built perl with a shared libperl.so on MirBSD (the
2595default config), it would work up to the installation; however, once
2596installed, it would be unable to find libperl. So path handling is now
2597treated as in the other BSD dialects.
5076a392 2598
554003a2 2599=head3 NetBSD
5076a392 2600
554003a2
FC
2601The NetBSD hints file has been changed to make the system's malloc the
2602default.
5076a392 2603
554003a2 2604=head3 Recent OpenBSDs now use perl's malloc
5076a392 2605
554003a2
FC
2606OpenBSD E<gt> 3.7 has a new malloc implementation which is mmap-based
2607and as such can release memory back to the OS; however, perl's use of
2608this malloc causes a substantial slowdown so we now default to using
2609perl's malloc instead [perl #75742].
5076a392 2610
554003a2 2611=head3 OpenVOS
5076a392 2612
554003a2 2613perl now builds again with OpenVOS (formerly known as Stratus VOS)
5a553547 2614[perl #78132] (5.12.3).
5076a392 2615
554003a2 2616=head3 Solaris
5076a392 2617
554003a2 2618DTrace is now supported on Solaris. There used to be build failures, but
5a553547 2619these have been fixed [perl #73630] (5.12.3).
5076a392 2620
554003a2 2621=head3 VMS
5076a392
FC
2622
2623=over
2624
2625=item *
2626
cdc10f43
FC
2627It's now possible to build extensions on older (pre 7.3-2) VMS systems.
2628
2629DCL symbol length was limited to 1K up until about seven years or
2630so ago, but there was no particularly deep reason to prevent those
2631older systems from configuring and building Perl (5.12.1).
2632
2633=item *
2634
2635We fixed the previously-broken C<-Uuseperlio> build on VMS.
2636
2637We were checking a variable that doesn't exist in the non-default
2638case of disabling perlio. Now we only look at it when it exists (5.12.1).
2639
2640=item *
2641
2642We fixed the -Uuseperlio command-line option in configure.com.
2643
2644Formerly it only worked if you went through all the questions
2645interactively and explicitly answered no (5.12.1).
2646
2647=item *
2648
554003a2 2649C<PerlIOUnix_open> now honours the default permissions on VMS.
5076a392 2650
554003a2
FC
2651When C<perlio> became the default and C<unixio> became the default bottom layer,
2652the most common path for creating files from Perl became C<PerlIOUnix_open>,
2653which has always explicitly used C<0666> as the permission mask.
5076a392 2654
554003a2
FC
2655To avoid this, C<0777> is now passed as the permissions to C<open()>. In the
2656VMS CRTL, C<0777> has a special meaning over and above intersecting with the
2657current umask; specifically, it allows Unix syscalls to preserve native default
5a553547
FC
2658permissions (5.12.3).
2659
2660=item *
2661
2662Spurious record boundaries are no longer
2663introduced by the PerlIO layer during output (5.12.3).
5076a392
FC
2664
2665=item *
2666
554003a2
FC
2667The shortening of symbols longer than 31 characters in the C sources is
2668now done by the compiler rather than by xsubpp (which could only do so
2669for generated symbols in XS code).
5076a392
FC
2670
2671=item *
2672
554003a2
FC
2673Record-oriented files (record format variable or variable with fixed control)
2674opened for write by the perlio layer will now be line-buffered to prevent the
2675introduction of spurious line breaks whenever the perlio buffer fills up.
5076a392 2676
d430b8e7
FC
2677=item *
2678
2679F<git_version.h> is now installed on VMS. This was an oversight in v5.12.0 which
2680caused some extensions to fail to build (5.12.2).
2681
2682=item *
2683
2684Several memory leaks in L<stat()|perlfunc/"stat FILEHANDLE"> have been fixed (5.12.2).
2685
2686=item *
2687
2688A memory leak in C<Perl_rename()> due to a double allocation has been
2689fixed (5.12.2).
2690
2691=item *
2692
2693A memory leak in C<vms_fid_to_name()> (used by C<realpath()> and
2694C<realname()>) has been fixed (5.12.2).
2695
5076a392
FC
2696=back
2697
554003a2 2698=head3 Windows
5076a392 2699
5a1f7719
FC
2700See also L</"fork() emulation will not wait for signalled children"> and
2701L</"Perl source code is read in text mode on Windows">, above.
2702
5076a392
FC
2703=over 4
2704
2705=item *
2706
554003a2 2707Fixed build process for SDK2003SP1 compilers.
5076a392 2708
554003a2 2709=item *
5076a392 2710
01b1a9e4
FC
2711Compilation with Visual Studio 2010 is now supported.
2712
2713=item *
2714
554003a2
FC
2715When using old 32-bit compilers, the define C<_USE_32BIT_TIME_T> will now
2716be set in C<$Config{ccflags}>. This improves portability when compiling
2717XS extensions using new compilers, but for a perl compiled with old 32-bit
2718compilers.
5076a392
FC
2719
2720=item *
2721
554003a2
FC
2722C<$Config{gccversion}> is now set correctly when perl is built using the
2723mingw64 compiler from L<http://mingw64.org> [perl #73754].
5076a392 2724
554003a2
FC
2725=item *
2726
d430b8e7
FC
2727When building Perl with the mingw64 x64 cross-compiler C<incpath>,
2728C<libpth>, C<ldflags>, C<lddlflags> and C<ldflags_nolargefiles> values
2729in F<Config.pm> and F<Config_heavy.pl> were not previously being set
2730correctly because, with that compiler, the include and lib directories
2731are not immediately below C<$(CCHOME)> (5.12.2).
2732
2733=item *
2734
554003a2
FC
2735The build process proceeds more smoothly with mingw and dmake when
2736F<C:\MSYS\bin> is in the PATH, due to a C<Cwd> fix.
5076a392
FC
2737
2738=item *
2739
554003a2
FC
2740Support for building with Visual C++ 2010 is now underway, but is not yet
2741complete. See F<README.win32> or L<perlwin32> for more details.
5076a392 2742
554003a2
FC
2743=item *
2744
2745The option to use an externally-supplied C<crypt()>, or to build with no
2746C<crypt()> at all, has been removed. Perl supplies its own C<crypt()>
2747implementation for Windows, and the political situation that required
2748this part of the distribution to sometimes be omitted is long gone.
5076a392
FC
2749
2750=back
2751
2752=head1 Internal Changes
2753
1e463951 2754=head2 New APIs
5076a392 2755
1e463951 2756=head3 CLONE_PARAMS structure added to ease correct thread creation
5076a392 2757
1e463951
FC
2758Modules that create threads should now create C<CLONE_PARAMS> structures
2759by calling the new function C<Perl_clone_params_new()>, and free them with
2760C<Perl_clone_params_del()>. This will ensure compatibility with any future
2761changes to the internals of the C<CLONE_PARAMS> structure layout, and that
2762it is correctly allocated and initialised.
5076a392 2763
1e463951 2764=head3 New parsing functions
5076a392 2765
1e463951
FC
2766Several functions have been added for parsing statements or multiple
2767statements:
5076a392 2768
1e463951 2769=over
5076a392
FC
2770
2771=item *
2772
1e463951 2773C<parse_fullstmt> parses a complete Perl statement.
5076a392
FC
2774
2775=item *
2776
1e463951
FC
2777C<parse_stmtseq> parses a sequence of statements, up
2778to closing brace or EOF.
5076a392
FC
2779
2780=item *
2781
1e463951 2782C<parse_block> parses a block [perl #78222].
5076a392
FC
2783
2784=item *
2785
1e463951
FC
2786C<parse_barestmt> parses a statement
2787without a label.
5076a392
FC
2788
2789=item *
2790
1e463951 2791C<parse_label> parses a statement label, separate from statements.
5076a392 2792
1e463951 2793=back
5076a392 2794
1e463951
FC
2795The
2796L<C<parse_fullexpr()>|perlapi/parse_fullexpr>,
2797L<C<parse_listexpr()>|perlapi/parse_listexpr>,
2798L<C<parse_termexpr()>|perlapi/parse_termexpr>, and
2799L<C<parse_arithexpr()>|perlapi/parse_arithexpr>
2800functions have been added to the API. They perform
2801recursive-descent parsing of expressions at various precedence levels.
2802They are expected to be used by syntax plugins.
5076a392 2803
1e463951 2804See L<perlapi> for details.
5076a392 2805
1e463951 2806=head3 Hints hash API
5076a392 2807
1e463951
FC
2808A new C API for introspecting the hinthash C<%^H> at runtime has been
2809added. See C<cop_hints_2hv>, C<cop_hints_fetchpvn>, C<cop_hints_fetchpvs>,
2810C<cop_hints_fetchsv>, and C<hv_copy_hints_hv> in L<perlapi> for details.
5076a392 2811
1e463951
FC
2812A new, experimental API has been added for accessing the internal
2813structure that Perl uses for C<%^H>. See the functions beginning with
2814C<cophh_> in L<perlapi>.
5076a392 2815
1e463951 2816=head3 C interface to C<caller()>
5076a392 2817
1e463951
FC
2818The C<caller_cx> function has been added as an XSUB-writer's equivalent of
2819C<caller()>. See L<perlapi> for details.
5076a392 2820
1e463951 2821=head3 Custom per-subroutine check hooks
5076a392 2822
1e463951
FC
2823XS code in an extension module can now annotate a subroutine (whether
2824implemented in XS or in Perl) so that nominated XS code will be called
2825at compile time (specifically as part of op checking) to change the op
2826tree of that subroutine. The compile-time check function (supplied by
2827the extension module) can implement argument processing that can't be
2828expressed as a prototype, generate customised compile-time warnings,
2829perform constant folding for a pure function, inline a subroutine
2830consisting of sufficiently simple ops, replace the whole call with a
2831custom op, and so on. This was previously all possible by hooking the
2832C<entersub> op checker, but the new mechanism makes it easy to tie the
2833hook to a specific subroutine. See L<perlapi/cv_set_call_checker>.
5076a392 2834
1e463951
FC
2835To help in writing custom check hooks, several subtasks within standard
2836C<entersub> op checking have been separated out and exposed in the API.
5076a392 2837
1e463951 2838=head3 Improved support for custom OPs
5076a392 2839
1e463951
FC
2840Custom ops can now be registered with the new C<custom_op_register> C
2841function and the C<XOP> structure. This will make it easier to add new
2842properties of custom ops in the future. Two new properties have been added
2843already, C<xop_class> and C<xop_peep>.
5076a392 2844
1e463951
FC
2845C<xop_class> is one of the OA_*OP constants, and allows L<B> and other
2846introspection mechanisms to work with custom ops
2847that aren't BASEOPs. C<xop_peep> is a pointer to
2848a function that will be called for ops of this
2849type from C<Perl_rpeep>.
5076a392 2850
1e463951
FC
2851See L<perlguts/Custom Operators> and L<perlapi/Custom Operators> for more
2852detail.
5076a392 2853
1e463951
FC
2854The old C<PL_custom_op_names>/C<PL_custom_op_descs> interface is still
2855supported but discouraged.
5076a392 2856
1e463951 2857=head3 Scope hooks
5076a392 2858
1e463951
FC
2859It is now possible for XS code to hook into Perl's lexical scope
2860mechanism at compile time, using the new C<Perl_blockhook_register>
2861function. See L<perlguts/"Compile-time scope hooks">.
5076a392 2862
1e463951 2863=head3 The recursive part of the peephole optimizer is now hookable
5076a392
FC
2864
2865In addition to C<PL_peepp>, for hooking into the toplevel peephole optimizer, a
2866C<PL_rpeepp> is now available to hook into the optimizer recursing into
2867side-chains of the optree.
2868
1e463951 2869=head3 New non-magical variants of existing functions
5076a392 2870
1e463951
FC
2871The following functions/macros have been added to the API. The C<*_nomg>
2872macros are equivalent to their non-_nomg variants, except that they ignore
2873get-magic. Those ending in C<_flags> allow one to specify whether
2874get-magic is processed.
5076a392 2875
1e463951
FC
2876 sv_2bool_flags
2877 SvTRUE_nomg
2878 sv_2nv_flags
2879 SvNV_nomg
2880 sv_cmp_flags
2881 sv_cmp_locale_flags
2882 sv_eq_flags
2883 sv_collxfrm_flags
5076a392 2884
1e463951 2885In some of these cases, the non-_flags functions have
5076a392
FC
2886been replaced with wrappers around the new functions.
2887
1e463951 2888=head3 pv/pvs/sv versions of existing functions
5076a392 2889
1e463951 2890Many functions ending with pvn now have equivalent pv/pvs/sv versions.
5076a392 2891
1e463951 2892=head3 List op-building functions
5076a392 2893
1e463951
FC
2894List op-building functions have been added to the
2895API. See L<op_append_elem|perlapi/op_append_elem>,
2896L<op_append_list|perlapi/op_append_list>, and
2897L<op_prepend_elem|perlapi/op_prepend_elem> in L<perlapi>.
5076a392 2898
1e463951 2899=head3 C<LINKLIST>
5076a392 2900
1e463951
FC
2901The L<LINKLIST|perlapi/LINKLIST> macro, part of op building that
2902constructs the execution-order op chain, has been added to the API.
5076a392 2903
1e463951 2904=head3 Localisation functions
5076a392 2905
1e463951
FC
2906The C<save_freeop>, C<save_op>, C<save_pushi32ptr> and C<save_pushptrptr>
2907functions have been added to the API.
5076a392 2908
1e463951 2909=head3 Stash names
5076a392 2910
1e463951
FC
2911A stash can now have a list of effective names in addition to its usual
2912name. The first effective name can be accessed via the C<HvENAME> macro,
2913which is now the recommended name to use in MRO linearisations (C<HvNAME>
2914being a fallback if there is no C<HvENAME>).
5076a392 2915
1e463951
FC
2916These names are added and deleted via C<hv_ename_add> and
2917C<hv_ename_delete>. These two functions are I<not> part of the API.
5076a392 2918
1e463951 2919=head3 New functions for finding and removing magic
5076a392 2920
1e463951
FC
2921The L<C<mg_findext()>|perlapi/mg_findext> and
2922L<C<sv_unmagicext()>|perlapi/sv_unmagicext>
2923functions have been added to the API.
2924They allow extension authors to find and remove magic attached to
2925scalars based on both the magic type and the magic virtual table, similar to how
2926C<sv_magicext()> attaches magic of a certain type and with a given virtual table
2927to a scalar. This eliminates the need for extensions to walk the list of
2928C<MAGIC> pointers of an C<SV> to find the magic that belongs to them.
5076a392 2929
1e463951 2930=head3 C<find_rundefsv>
5076a392 2931
1e463951
FC
2932This function returns the SV representing C<$_>, whether it's lexical
2933or dynamic.
5076a392 2934
1e463951 2935=head3 C<Perl_croak_no_modify>
5076a392 2936
1e463951
FC
2937C<Perl_croak_no_modify()> is short-hand for
2938C<Perl_croak("%s", PL_no_modify)>.
5076a392 2939
1e463951 2940=head3 C<PERL_STATIC_INLINE> define
5076a392 2941
1e463951
FC
2942The C<PERL_STATIC_INLINE> define has been added to provide the best-guess
2943incantation to use for static inline functions, if the C compiler supports
2944C99-style static inline. If it doesn't, it'll give a plain C<static>.
5076a392 2945
1e463951
FC
2946C<HAS_STATIC_INLINE> can be used to check if the compiler actually supports
2947inline functions.
5076a392 2948
1e463951 2949=head3 New C<pv_escape> option for hexadecimal escapes
5076a392 2950
1e463951
FC
2951A new option, C<PERL_PV_ESCAPE_NONASCII>, has been added to C<pv_escape> to
2952dump all characters above ASCII in hexadecimal. Before, one could get all
2953characters as hexadecimal or the Latin1 non-ASCII as octal.
5076a392 2954
1e463951 2955=head3 C<lex_start>
5076a392 2956
1e463951 2957C<lex_start> has been added to the API, but is considered experimental.
5076a392 2958
1e463951 2959=head3 C<op_scope()> and C<op_lvalue()>
5076a392 2960
1e463951
FC
2961The C<op_scope()> and C<op_lvalue()> functions have been added to the API,
2962but are considered experimental.
5076a392 2963
1e463951 2964=head2 C API Changes
5076a392 2965
1e463951 2966=head3 C<PERL_POLLUTE> has been removed
5076a392 2967
1e463951
FC
2968The option to define C<PERL_POLLUTE> to expose older 5.005 symbols for
2969backwards compatibility has been removed. It's use was always discouraged,
2970and MakeMaker contains a more specific escape hatch:
5076a392 2971
1e463951 2972 perl Makefile.PL POLLUTE=1
5076a392 2973
1e463951
FC
2974This can be used for modules that have not been upgraded to 5.6 naming
2975conventions (and really should be completely obsolete by now).
5076a392 2976
1e463951 2977=head3 Check API compatibility when loading XS modules
5076a392 2978
1e463951
FC
2979When perl's API changes in incompatible ways (which usually happens between
2980major releases), XS modules compiled for previous versions of perl will not
2981work anymore. They will need to be recompiled against the new perl.
5076a392 2982
1e463951
FC
2983In order to ensure that modules are recompiled, and to prevent users from
2984accidentally loading modules compiled for old perls into newer ones, the
2985C<XS_APIVERSION_BOOTCHECK> macro has been added. That macro, which is
2986called when loading every newly compiled extension, compares the API
2987version of the running perl with the version a module has been compiled for
2988and raises an exception if they don't match.
5076a392 2989
1e463951 2990=head3 Perl_fetch_cop_label
5076a392 2991
1e463951
FC
2992The first argument of the C API function C<Perl_fetch_cop_label> has changed
2993from C<struct refcounted he *> to C<COP *>, to insulate the user from
2994implementation details.
5076a392 2995
1e463951
FC
2996This API function was marked as "may change", and likely isn't in use outside
2997the core. (Neither an unpacked CPAN, nor Google's codesearch, finds any other
2998references to it.)
5076a392 2999
1e463951 3000=head3 GvCV() and GvGP() are no longer lvalues
5076a392 3001
1e463951
FC
3002The new GvCV_set() and GvGP_set() macros are now provided to replace
3003assignment to those two macros.
5076a392 3004
1e463951
FC
3005This allows a future commit to eliminate some backref magic between GV
3006and CVs, which will require complete control over assignment to the
3007gp_cv slot.
5076a392 3008
1e463951 3009=head3 CvGV() is no longer an lvalue
5076a392 3010
1e463951
FC
3011Under some circumstances, the C<CvGV()> field of a CV is now
3012reference-counted. To ensure consistent behaviour, direct assignment to
3013it, for example C<CvGV(cv) = gv> is now a compile-time error. A new macro,
3014C<CvGV_set(cv,gv)> has been introduced to perform this operation
3015safely. Note that modification of this field is not part of the public
3016API, regardless of this new macro (and despite its being listed in this section).
5076a392 3017
1e463951 3018=head3 CvSTASH() is no longer an lvalue
5076a392 3019
1e463951
FC
3020The C<CvSTASH()> macro can now only be used as an rvalue. C<CvSTASH_set()>
3021has been added to replace assignment to C<CvSTASH()>. This is to ensure
3022that backreferences are handled properly. These macros are not part of the
3023API.
5076a392 3024
1e463951 3025=head3 Calling conventions for C<newFOROP> and C<newWHILEOP>
5076a392 3026
1e463951
FC
3027The way the parser handles labels has been cleaned up and refactored. As a
3028result, the C<newFOROP()> constructor function no longer takes a parameter
3029stating what label is to go in the state op.
5076a392 3030
1e463951
FC
3031The C<newWHILEOP()> and C<newFOROP()> functions no longer accept a line
3032number as a parameter.
5076a392 3033
1e463951 3034=head3 Flags passed to C<uvuni_to_utf8_flags> and C<utf8n_to_uvuni>
5076a392 3035
1e463951
FC
3036Some of the flags parameters to uvuni_to_utf8_flags() and
3037utf8n_to_uvuni() have changed. This is a result of Perl's now allowing
5076a392
FC
3038internal storage and manipulation of code points that are problematic
3039in some situations. Hence, the default actions for these functions has
3040been complemented to allow these code points. The new flags are
3041documented in L<perlapi>. Code that requires the problematic code
483b16f3 3042points to be rejected needs to change to use the new flags. Some flag
5076a392
FC
3043names are retained for backward source compatibility, though they do
3044nothing, as they are now the default. However the flags
3045C<UNICODE_ALLOW_FDD0>, C<UNICODE_ALLOW_FFFF>, C<UNICODE_ILLEGAL>, and
3046C<UNICODE_IS_ILLEGAL> have been removed, as they stem from a
3047fundamentally broken model of how the Unicode non-character code points
3048should be handled, which is now described in
3049L<perlunicode/Non-character code points>. See also L</Selected Bug Fixes>.
3050
1e463951 3051XXX Which bugs in particular? Selected Bug Fixes is too long for this link
483b16f3
KW
3052to be meaningful right now
3053I don't see the bugs in that section currently -- khw
5076a392 3054
1e463951 3055=head2 Deprecated C APIs
5076a392 3056
1e463951 3057=over
5076a392 3058
1e463951 3059=item C<Perl_ptr_table_clear>
5076a392 3060
1e463951
FC
3061C<Perl_ptr_table_clear> is no longer part of Perl's public API. Calling it
3062now generates a deprecation warning, and it will be removed in a future
3063release.
5076a392 3064
1e463951 3065=item C<sv_compile_2op>
5076a392 3066
1e463951
FC
3067The C<sv_compile_2op()> API function is now deprecated. Searches suggest
3068that nothing on CPAN is using it, so this should have zero impact.
5076a392 3069
1e463951
FC
3070It attempted to provide an API to compile code down to an optree, but failed
3071to bind correctly to lexicals in the enclosing scope. It's not possible to
3072fix this problem within the constraints of its parameters and return value.
5076a392 3073
1e463951 3074=item C<find_rundefsvoffset>
5076a392 3075
1e463951
FC
3076The C<find_rundefsvoffset> function has been deprecated. It appeared that
3077its design was insufficient for reliably getting the lexical C<$_> at
3078run-time.
5076a392 3079
1e463951
FC
3080Use the new C<find_rundefsv> function or the C<UNDERBAR> macro
3081instead. They directly return the right SV representing C<$_>, whether it's
3082lexical or dynamic.
5076a392 3083
1e463951 3084=item C<CALL_FPTR> and C<CPERLscope>
5076a392 3085
1e463951
FC
3086Those are left from an old implementation of C<MULTIPLICITY> using C++ objects,
3087which was removed in Perl 5.8. Nowadays these macros do exactly nothing, so
3088they shouldn't be used anymore.
5076a392 3089
1e463951
FC
3090For compatibility, they are still defined for external C<XS> code. Only
3091extensions defining C<PERL_CORE> must be updated now.
5076a392 3092
1e463951 3093=back
5076a392 3094
1e463951 3095=head2 Other Internal Changes
5076a392 3096
1e463951 3097=head3 Stack unwinding
5076a392 3098
1e463951
FC
3099The protocol for unwinding the C stack at the last stage of a C<die>
3100has changed how it identifies the target stack frame. This now uses
3101a separate variable C<PL_restartjmpenv>, where previously it relied on
3102the C<blk_eval.cur_top_env> pointer in the C<eval> context frame that
3103has nominally just been discarded. This change means that code running
3104during various stages of Perl-level unwinding no longer needs to take
3105care to avoid destroying the ghost frame.
5076a392 3106
1e463951 3107=head3 Scope stack entries
5076a392 3108
1e463951
FC
3109The format of entries on the scope stack has been changed, resulting in a
3110reduction of memory usage of about 10%. In particular, the memory used by
3111the scope stack to record each active lexical variable has been halved.
5076a392 3112
1e463951 3113=head3 Memory allocation for pointer tables
5076a392 3114
1e463951
FC
3115Memory allocation for pointer tables has been changed. Previously
3116C<Perl_ptr_table_store> allocated memory from the same arena system as
3117C<SV> bodies and C<HE>s, with freed memory remaining bound to those arenas
3118until interpreter exit. Now it allocates memory from arenas private to the
3119specific pointer table, and that memory is returned to the system when
3120C<Perl_ptr_table_free> is called. Additionally, allocation and release are
3121both less CPU intensive.
5076a392 3122
1e463951 3123=head3 C<UNDERBAR>
5076a392 3124
1e463951
FC
3125The C<UNDERBAR> macro now calls C<find_rundefsv>. C<dUNDERBAR> is now a
3126noop but should still be used to ensure past and future compatibility.
5076a392 3127
1e463951 3128=head3 String comparison routines renamed
5076a392 3129
1e463951
FC
3130The ibcmp_* functions have been renamed and are now called foldEQ,
3131foldEQ_locale and foldEQ_utf8. The old names are still available as
3132macros.
3133
3134=head3 C<chop> and C<chomp> implementations merged
3135
3136The opcode bodies for C<chop> and C<chomp> and for C<schop> and C<schomp>
3137have been merged. The implementation functions C<Perl_do_chop()> and
3138C<Perl_do_chomp()>, never part of the public API, have been merged and
3139moved to a static function in F<pp.c>. This shrinks the perl binary
3140slightly, and should not affect any code outside the core (unless it is
3141relying on the order of side effects when C<chomp> is passed a I<list> of
3142values).
5076a392
FC
3143
3144=head1 Selected Bug Fixes
3145
e8e35311
FC
3146=head2 I/O
3147
5076a392
FC
3148=over 4
3149
3150=item *
3151
e8e35311 3152Perl no longer produces this warning:
a593b319
FC
3153
3154 $ perl -we 'open my $f, ">", \my $x; binmode $f, "scalar"'
3155 Use of uninitialized value in binmode at -e line 1.
3156
3157=item *
3158
e8e35311
FC
3159Opening a glob reference via C<< open $fh, "E<gt>", \*glob >> will no longer
3160cause the glob to be corrupted when the filehandle is printed to. This would
3161cause perl to crash whenever the glob's contents were accessed
3162[perl #77492].
4ed2cea4
FC
3163
3164=item *
3165
e8e35311
FC
3166PerlIO no longer crashes when called recursively, e.g., from a signal
3167handler. Now it just leaks memory [perl #75556].
4ed2cea4
FC
3168
3169=item *
3170
e8e35311
FC
3171Most I/O functions were not warning for unopened handles unless the
3172'closed' and 'unopened' warnings categories were both enabled. Now only
3173C<use warnings 'unopened'> is necessary to trigger these warnings (as was
438c239f 3174always meant to be the case).
4ed2cea4
FC
3175
3176=item *
3177
438c239f 3178There have been several fixes to PerlIO layers:
e8e35311 3179
438c239f
FC
3180When C<binmode FH, ":crlf"> pushes the C<:crlf> layer on top of the stack,
3181it no longer enables crlf layers lower in the stack, to avoid unexpected
3182results [perl #38456].
4ed2cea4 3183
438c239f
FC
3184Opening a file in C<:raw> mode now does what it advertises to do (first
3185open the file, then binmode it), instead of simply leaving off the top
3186layer [perl #80764].
5076a392 3187
438c239f
FC
3188The three layers C<:pop>, C<:utf8> and C<:bytes> didn't allow stacking when
3189opening a file. For example
e8e35311 3190this:
5076a392 3191
e8e35311 3192 open FH, '>:pop:perlio', 'some.file' or die $!;
5076a392 3193
438c239f
FC
3194Would throw an error: "Invalid argument". This has been fixed in this
3195release [perl #82484].
5076a392 3196
e8e35311
FC
3197=back
3198
3199=head2 Regular Expression Bug Fixes
3200
3201=over
5076a392
FC
3202
3203=item *
3204
e8e35311
FC
3205The regular expression engine no longer loops when matching
3206C<"\N{LATIN SMALL LIGATURE FF}" =~ /f+/i> and similar expressions
cdc10f43 3207[perl #72998] (5.12.1).
5076a392
FC
3208
3209=item *
3210
e8e35311
FC
3211The trie runtime code should no longer allocate massive amounts of memory,
3212fixing #74484.
5076a392
FC
3213
3214=item *
3215
438c239f
FC
3216Syntax errors in C<< (?{...}) >> blocks no longer cause panic messages
3217[perl #2353].
5076a392
FC
3218
3219=item *
3220
438c239f
FC
3221A pattern like C<(?:(o){2})?> no longer causes a "panic" error
3222[perl #39233].
5076a392
FC
3223
3224=item *
3225
438c239f 3226A fatal error in regular expressions containing C<(.*?)> when processing
d430b8e7 3227UTF-8 data has been fixed [perl #75680] (5.12.2).
5076a392
FC
3228
3229=item *
3230
e8e35311 3231An erroneous regular expression engine optimisation that caused regex verbs like
438c239f 3232C<*COMMIT> sometimes to be ignored has been removed.
5076a392
FC
3233
3234=item *
3235
e8e35311
FC
3236The regular expression bracketed character class C<[\8\9]> was effectively the
3237same as C<[89\000]>, incorrectly matching a NULL character. It also gave
3238incorrect warnings that the C<8> and C<9> were ignored. Now C<[\8\9]> is the
3239same as C<[89]> and gives legitimate warnings that C<\8> and C<\9> are
3240unrecognized escape sequences, passed-through.
5076a392
FC
3241
3242=item *
3243
e8e35311
FC
3244A regular expression match in the right-hand side of a global substitution
3245(C<s///g>) that is in the same scope will no longer cause match variables
3246to have the wrong values on subsequent iterations. This can happen when an
3247array or hash subscript is interpolated in the right-hand side, as in
3248C<s|(.)|@a{ print($1), /./ }|g> [perl #19078].
5076a392
FC
3249
3250=item *
3251
438c239f
FC
3252Several cases in which characters in the Latin-1 non-ASCII range (0x80 to
32530xFF) used not to match themselves or used to match both a character class
3254and its complement have been fixed. For instance, U+00E2 could match both
3255C<\w> and C<\W> [perl #78464] [perl #18281] [perl #60156].
5076a392
FC
3256
3257=item *
3258
e8e35311
FC
3259Matching a Unicode character against an alternation containing characters
3260that happened to match continuation bytes in the former's UTF8
3261representation (C<qq{\x{30ab}} =~ /\xab|\xa9/>) would cause erroneous
3262warnings [perl #70998].
5076a392
FC
3263
3264=item *
3265
e8e35311
FC
3266The trie optimisation was not taking empty groups into account, preventing
3267'foo' from matching C</\A(?:(?:)foo|bar|zot)\z/> [perl #78356].
5076a392
FC
3268
3269=item *
3270
e8e35311
FC
3271A pattern containing a C<+> inside a lookahead would sometimes cause an
3272incorrect match failure in a global match (e.g., C</(?=(\S+))/g>)
3273[perl #68564].
5076a392
FC
3274
3275=item *
3276
e8e35311
FC
3277A regular expression optimisation would sometimes cause a match with a
3278C<{n,m}> quantifier to fail when it should match [perl #79152].
5076a392
FC
3279
3280=item *
3281
e8e35311 3282Case insensitive matching in regular expressions compiled under C<use
438c239f
FC
3283locale> now works much more sanely when the pattern or
3284target string is encoded internally in
3285UTF8. Previously, under these conditions the localeness
e8e35311
FC
3286was completely lost. Now, code points above 255 are treated as Unicode,
3287but code points between 0 and 255 are treated using the current locale
438c239f
FC
3288rules, regardless of whether the pattern or the string is encoded in UTF8.
3289The few case-insensitive matches that cross the 255/256 boundary are not
e8e35311
FC
3290allowed. For example, 0xFF does not caselessly match the character at
32910x178, LATIN CAPITAL LETTER Y WITH DIAERESIS, because 0xFF may not be
3292LATIN SMALL LETTER Y in the current locale, and Perl has no way of
3293knowing if that character even exists in the locale, much less what code
3294point it is.
5076a392
FC
3295
3296=item *
3297
e8e35311
FC
3298The C<(?|...)> regular expression construct no longer crashes if the final
3299branch has more sets of capturing parentheses than any other branch. This
3300was fixed in Perl 5.10.1 for the case of a single branch, but that fix did
3301not take multiple branches into account [perl #84746].
5076a392
FC
3302
3303=item *
3304
e8e35311
FC
3305A bug has been fixed in the implementation of C<{...}> quantifiers in
3306regular expressions that prevented the code block in
3307C</((\w+)(?{ print $2 })){2}/> from seeing the C<$2> sometimes
3308[perl #84294].
5076a392 3309
e8e35311 3310=back
5076a392 3311
e8e35311
FC
3312=head2 Syntax/Parsing Bugs
3313
3314=over
5076a392
FC
3315
3316=item *
3317
e8e35311 3318C<when(scalar){...}> no longer crashes, but produces a syntax error
cdc10f43 3319[perl #74114] (5.12.1).
5076a392
FC
3320
3321=item *
3322
e8e35311
FC
3323A label right before a string eval (C<foo: eval $string>) no longer causes
3324the label to be associated also with the first statement inside the eval
3325[perl #74290] (5.12.1).
5076a392
FC
3326
3327=item *
3328
b2c076b5 3329The C<no 5.13.2;> form of C<no> no longer tries to turn on features or
d430b8e7 3330pragmata (i.e., strict) [perl #70075] (5.12.2).
5076a392
FC
3331
3332=item *
3333
b2c076b5
FC
3334C<BEGIN {require 5.12.0}> now behaves as documented, rather than behaving
3335identically to C<use 5.12.0;>. Previously, C<require> in a C<BEGIN> block
3336was erroneously executing the C<use feature ':5.12.0'> and
3337C<use strict;> behaviour, which only C<use> was documented to
3338provide [perl #69050].
5076a392
FC
3339
3340=item *
3341
5076a392
FC
3342A regression introduced in Perl 5.12.0, making
3343C<< my $x = 3; $x = length(undef) >> result in C<$x> set to C<3> has been
d430b8e7 3344fixed. C<$x> will now be C<undef> [perl #85508] (5.12.2).
b2c076b5
FC
3345
3346=item *
3347
3348When strict 'refs' mode is off, C<%{...}> in rvalue context returns
3349C<undef> if its argument is undefined. An optimisation introduced in perl
33505.12.0 to make C<keys %{...}> faster when used as a boolean did not take
3351this into account, causing C<keys %{+undef}> (and C<keys %$foo> when
3352C<$foo> is undefined) to be an error, which it should only be in strict
3353mode [perl #81750].
5076a392
FC
3354
3355=item *
3356
e8e35311 3357Constant-folding used to cause
5076a392 3358
e8e35311 3359 $text =~ ( 1 ? /phoo/ : /bear/)
5076a392 3360
e8e35311
FC
3361to turn into
3362
3363 $text =~ /phoo/
3364
3365at compile time. Now it correctly matches against C<$_> [perl #20444].
5076a392
FC
3366
3367=item *
3368
e8e35311
FC
3369Parsing Perl code (either with string C<eval> or by loading modules) from
3370within a C<UNITCHECK> block no longer causes the interpreter to crash
3371[perl #70614].
5076a392
FC
3372
3373=item *
3374
b2c076b5
FC
3375String evals no longer fail after 2 billion scopes have been
3376compiled [perl #83364].
3377
3378=item *
3379
e8e35311
FC
3380The parser no longer hangs when encountering certain Unicode characters,
3381such as U+387 [perl #74022].
5076a392
FC
3382
3383=item *
3384
b2c076b5
FC
3385Several contexts no longer allow a Unicode character to begin a word
3386that should never begin words, for an example an accent that must follow
3387another character previously could precede all other characters.
5076a392
FC
3388
3389=item *
3390
e8e35311
FC
3391Defining a constant with the same name as one of perl's special blocks
3392(e.g., INIT) stopped working in 5.12.0, but has now been fixed
3393[perl #78634].
5076a392
FC
3394
3395=item *
3396
e8e35311
FC
3397A reference to a literal value used as a hash key (C<$hash{\"foo"}>) used
3398to be stringified, even if the hash was tied [perl #79178].
5076a392
FC
3399
3400=item *
3401
e8e35311
FC
3402A closure containing an C<if> statement followed by a constant or variable
3403is no longer treated as a constant [perl #63540].
5076a392
FC
3404
3405=item *
3406
e8e35311
FC
3407C<state> can now be used with attributes. It used to mean the same thing as
3408C<my> if attributes were present [perl #68658].
5076a392
FC
3409
3410=item *
3411
e8e35311
FC
3412Expressions like C<< @$a > 3 >> no longer cause C<$a> to be mentioned in
3413the "Use of uninitialized value in numeric gt" warning when C<$a> is
3414undefined (since it is not part of the C<E<gt>> expression, but the operand
3415of the C<@>) [perl #72090].
5076a392
FC
3416
3417=item *
3418
e8e35311
FC
3419Accessing an element of a package array with a hard-coded number (as
3420opposed to an arbitrary expression) would crash if the array did not exist.
3421Usually the array would be autovivified during compilation, but typeglob
3422manipulation could remove it, as in these two cases which used to crash:
5076a392 3423
e8e35311
FC
3424 *d = *a; print $d[0];
3425 undef *d; print $d[0];
5076a392 3426
2c389f6c
FC
3427=item *
3428
3429The C<-C> command line option, when used on the shebang line, can now be
3430followed by other options [perl #72434].
3431
3432=item *
3433
3434The C<B> module was returning C<B::OP>s instead of C<B::LOGOP>s for C<entertry> [perl #80622].
3435This was due to a bug in the perl core, not in C<B> itself.
3436
e8e35311 3437=back
5076a392 3438
e262cb24
FC
3439=head2 Stashes, Globs and Method Lookup
3440
3441Perl 5.10.0 introduced a new internal mechanism for caching MROs (method
3442resolution orders, or lists of parent classes; aka "isa" caches) to make
3443method lookup faster (so @ISA arrays would not have to be searched
3444repeatedly). Unfortunately, this brought with it quite a few bugs. Almost
3445all of these have been fixed now, along with a few MRO-related bugs that
3446existed before 5.10.0:
3447
3448=over
3449
3450=item *
3451
3452The following used to have erratic effects on method resolution, because
3453the "isa" caches were not reset or otherwise ended up listing the wrong
3454classes. These have been fixed.
3455
3456=over
3457
3458=item Aliasing packages by assigning to globs [perl #77358]
3459
3460=item Deleting packages by deleting their containing stash elements
3461
3462=item Undefining the glob containing a package (C<undef *Foo::>)
3463
3464=item Undefining an ISA glob (C<undef *Foo::ISA>)
3465
3466=item Deleting an ISA stash element (C<delete $Foo::{ISA}>)
3467
3468=item Sharing @ISA arrays between classes (via C<*Foo::ISA = \@Bar::ISA> or
3469C<*Foo::ISA = *Bar::ISA>) [perl #77238]
3470
3471=back
3472
3473C<undef *Foo::ISA> would even stop a new C<@Foo::ISA> array from updating
3474caches.
3475
3476=item *
3477
3478Typeglob assignments would crash if the glob's stash no longer existed, so
3479long as the glob assigned to was named 'ISA' or the glob on either side of
3480the assignment contained a subroutine.
3481
3482=item *
3483
3484C<PL_isarev>, which is accessible to Perl via C<mro::get_isarev> is now
3485updated properly when packages are deleted or removed from the C<@ISA> of
3486other classes. This allows many packages to be created and deleted without
3487causing a memory leak [perl #75176].
3488
3489=back
3490
3491In addition, various other bugs related to typeglobs and stashes have been
3492fixed:
5076a392 3493
e8e35311 3494=over
5076a392
FC
3495
3496=item *
3497
e8e35311 3498Some work has been done on the internal pointers that link between symbol
e262cb24 3499tables (stashes), typeglobs and subroutines. This has the effect that
e8e35311
FC
3500various edge cases related to deleting stashes or stash entries (e.g.
3501<%FOO:: = ()>), and complex typeglob or code reference aliasing, will no
3502longer crash the interpreter.
5076a392
FC
3503
3504=item *
3505
e262cb24
FC
3506Assigning a reference to a glob copy now assigns to a glob slot instead of
3507overwriting the glob with a scalar [perl #1804] [perl #77508].
5076a392
FC
3508
3509=item *
3510
e8e35311
FC
3511A bug when replacing the glob of a loop variable within the loop has been fixed
3512[perl #21469]. This
3513means the following code will no longer crash:
5076a392 3514
e8e35311
FC
3515 for $x (...) {
3516 *x = *y;
3517 }
5076a392
FC
3518
3519=item *
3520
3521Assigning a glob to a PVLV used to convert it to a plain string. Now it
3522works correctly, and a PVLV can hold a glob. This would happen when a
3523nonexistent hash or array element was passed to a subroutine:
3524
3525 sub { $_[0] = *foo }->($hash{key});
3526 # $_[0] would have been the string "*main::foo"
3527
3528It also happened when a glob was assigned to, or returned from, an element
3529of a tied array or hash [perl #36051].
3530
3531=item *
44691e6f 3532
e8e35311 3533When trying to report C<Use of uninitialized value $Foo::BAR>, crashes could
e262cb24
FC
3534occur if the glob holding the global variable in question had been detached
3535from its original stash by, for example, C<delete $::{'Foo::'}>. This has
3536been fixed by disabling the reporting of variable names in those
e8e35311 3537cases.
44691e6f
AB
3538
3539=item *
3540
e8e35311
FC
3541During the restoration of a localised typeglob on scope exit, any
3542destructors called as a result would be able to see the typeglob in an
3543inconsistent state, containing freed entries, which could result in a
3544crash. This would affect code like this:
3545
3546 local *@;
3547 eval { die bless [] }; # puts an object in $@
3548 sub DESTROY {
3549 local $@; # boom
3550 }
3551
3552Now the glob entries are cleared before any destructors are called. This
3553also means that destructors can vivify entries in the glob. So perl tries
3554again and, if the entries are re-created too many times, dies with a
3555'panic: gp_free...' error message.
3556
3557=back
3558
3559=head2 Unicode
3560
3561=over
44691e6f 3562
5076a392 3563=item *
44691e6f 3564