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AB
1=encoding utf8
2
541cb22c 3=for comment
5dd80d85 4This has been completed up to 6728c8514a, except for
d6b99bf4 5b0f2e9e nwclark Fix two bugs related to pod files outside of pod/ (important enough?)
7f28d7ed
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643d9ecf jpeacock Set all version object math ops to noop
7f300909 smueller EU::ParseXS: Silence warning (probably unnecessary)
541cb22c 8
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9=head1 NAME
10
0aaeb177
SH
11[ this is a template for a new perldelta file. Any text flagged as
12XXX needs to be processed before release. ]
760696b8 13
0aaeb177 14perldelta - what is new for perl v5.15.6
062678b2 15
0aaeb177 16=head1 DESCRIPTION
ad32999b 17
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18This document describes differences between the 5.15.5 release and
19the 5.15.6 release.
ad32999b 20
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21If you are upgrading from an earlier release such as 5.15.4, first read
22L<perl5155delta>, which describes differences between 5.15.4 and
235.15.5.
ad32999b 24
0aaeb177 25=head1 Notice
ad32999b 26
0aaeb177 27XXX Any important notices here
ad32999b 28
0aaeb177 29=head1 Core Enhancements
a3f52e2e 30
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31XXX New core language features go here. Summarise user-visible core language
32enhancements. Particularly prominent performance optimisations could go
33here, but most should go in the L</Performance Enhancements> section.
a3f52e2e 34
0aaeb177 35[ List each enhancement as a =head2 entry ]
6d110ad0 36
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37=head2 C<__SUB__>
38
39The new C<__SUB__> token, available under the "current_sub" feature (see
40L<feature>) or C<use v5.15>, returns a reference to the current subroutine,
41making it easier to write recursive closures.
42
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43=head2 New option for the debugger's B<t> command
44
45The B<t> command in the debugger, which toggles tracing mode, now accepts a
46numerical argument that determines how many levels of subroutine calls to
47trace.
48
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49=head2 Return value of C<tied>
50
51The value returned by C<tied> on a tied variable is now the actual scalar
52that holds the object to which the variable is tied. This allows ties to
53be weakened with C<Scalar::Util::weaken(tied $tied_variable)>.
54
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55=head2 Lvalue C<scalar>
56
57C<scalar> can now be used as an lvalue. You might consider this a new
58feature (which is why it is listed in this section), but the author of
59the change considered it a bug fix, since C<scalar> is only supposed to be
60setting scalar context, not changing lvalueness [perl #24346].
61
e3c71926 62=head1 Security
6d110ad0 63
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64XXX Any security-related notices go here. In particular, any security
65vulnerabilities closed should be noted here rather than in the
66L</Selected Bug Fixes> section.
6d110ad0 67
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68=head2 C<is_utf8_char()>
69
70The XS-callable function C<is_utf8_char()> when presented with malformed
71UTF-8 input can read up to 12 bytes beyond the end of the string. This
72cannot be fixed without changing its API. It is not called from CPAN.
73The documentation for it now describes how to use it safely.
74
75=head2 Other C<is_utf8_foo()> functions, as well as C<utf8_to_foo()>, etc.
76
77Most of the other XS-callable functions that take UTF-8 encoded input
78implicitly assume that the UTF-8 is valid (not malformed) in regards to
79buffer length. Do not do things such as change a character's case or
80see if it is alphanumeric without first being sure that it is valid
81UTF-8. This can be safely done for a whole string by using one of the
82functions C<is_utf8_string()>, C<is_utf8_string_loc()>, and
83C<is_utf8_string_loclen()>.
6d110ad0 84
e3c71926 85=head1 Incompatible Changes
6d110ad0 86
0aaeb177 87XXX For a release on a stable branch, this section aspires to be:
ad32999b 88
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SH
89 There are no changes intentionally incompatible with 5.XXX.XXX
90 If any exist, they are bugs and reports are welcome.
ad32999b 91
0aaeb177 92[ List each incompatible change as a =head2 entry ]
ad32999b 93
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94=head2 C<use I<VERSION>>
95
96As of this release, version declarations like C<use v5.16> now disable all
97features before enabling the new feature bundle. This means that the
98following holds true:
99
100 use 5.016;
101 # 5.16 features enabled here
102 use 5.014;
103 # 5.16 features disabled here
104
105C<use v5.12> and higher continue to enable strict, but explicit
106C<use strict> and C<no strict> now override the version declaration, even
107when they come first:
108
109 no strict;
110 use 5.012;
111 # no strict here
112
113There is a new ":default" feature bundle, that represents the set of
114features enabled before any version declaration or C<use feature> has been
115seen. Version declarations below 5.10 now enable the ":default" feature
116set. This does not actually change the behaviour of C<use v5.8>, because
117features added to the ":default" set are those that were traditionally
118enabled by default, before they could be turned off.
119
120C<$[> is now disabled under C<use v5.16>. It is part of the default
121feature set and can be turned on or off explicitly
122with C<use feature 'array_base'>.
123
124=head2 C<UNIVERSAL::VERSION>
125
126The change to C<UNIVERSAL::VERSION> in 5.15.2 has been reverted. It now
127returns a stringified version object once more.
128
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129=head2 C<substr> lvalue revamp
130
131When C<substr> is called in lvalue or potential lvalue context with two or
132three arguments, a special lvalue scalar is returned that modifies the
133original string (the first argument) when assigned to.
134
135Previously, the offsets (the second and third arguments) passed to
136C<substr> would be converted immediately to match the string, negative
137offsets being translated to positive and offsets beyond the end of the
138string being truncated.
139
140Now, the offsets are recorded without modification in the special lvalue
141scalar that is returned, and the original string is not even looked at by
142C<substr> itself, but only when the returned lvalue is read or modified.
143
144These changes result in several incompatible changes and bug fixes:
145
146=over
147
148=item *
149
150If the original string changes length after the call to C<substr> but
151before assignment to its return value, negative offsets will remember
152their position from the end of the string, affecting code like this:
153
154 my $string = "string";
155 my $lvalue = \substr $string, -4, 2;
156 print $lvalue, "\n"; # prints "ri"
157 $string = "bailing twine";
158 print $lvalue, "\n"; # prints "wi"; used to print "il"
159
160The same thing happens with an omitted third argument. The returned lvalue
161will always extend to the end of the string, even if the string becomes
162longer.
163
164=item *
165
166Tied (and otherwise magical) variables are no longer exempt from the
167"Attempt ot use reference as lvalue in substr" warning.
168
169=item *
170
171That warning now occurs when the returned lvalue is assigned to, not when
172C<substr> itself is called. This only makes a difference if the return
173value of C<substr> is referenced and assigned to later.
174
175=item *
176
177The order in which "uninitialized" warnings occur for arguments to
178C<substr> has changed.
179
180=item *
181
182Passing a substring of a read-only value or a typeglob to a function (potential lvalue context) no longer causes an immediate "Can't coerce" or "Modification of a read-only value" error. That error only occurs if and
183when the value passed is assigned to.
184
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185The same thing happens with the "substr outside of string" error. If the
186lvalue is only read, not written to, it is now just a warning, as with
187rvalue C<substr>.
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188
189=item *
190
191C<substr> assignments no longer call FETCH twice if the first argument is a
192tied variable, but just once.
193
194=back
195
196It was impossible to fix all the bugs without an incompatible change, and
197the behaviour of negative offsets was never specified, so the change was
198deemed acceptable.
199
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200=head2 Return value of C<eval>
201
202C<eval> returns C<undef> in scalar context or an empty list in list context
203when there is a run-time error. For syntax errors (when C<eval> is passed
204a string), in list context it used to return a list containing a single
205undefined element. Now it returns an empty list in list context for all
206errors [perl #80630].
207
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208=head2 Anonymous handles
209
210Automatically generated file handles are now named __ANONIO__ when the
211variable name cannot be determined, rather than $__ANONIO__.
212
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213=head2 XS API tweak
214
215The C<newCONSTSUB_flags> C-level function, added in 5.15.4, now has a
216C<len> parameter.
217
e3c71926 218=head1 Deprecations
6d110ad0 219
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220XXX Any deprecated features, syntax, modules etc. should be listed here.
221In particular, deprecated modules should be listed here even if they are
222listed as an updated module in the L</Modules and Pragmata> section.
ae92a9ae 223
0aaeb177 224[ List each deprecation as a =head2 entry ]
ae92a9ae 225
e3c71926 226=head1 Performance Enhancements
6d110ad0 227
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228XXX Changes which enhance performance without changing behaviour go here. There
229may well be none in a stable release.
230
231[ List each enhancement as a =item entry ]
232
e3c71926 233=over 4
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234
235=item *
236
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237Perl 5.12.0 sped up the destruction of objects whose classes define empty
238C<DESTROY> methods (to prevent autoloading), simply by not calling such
239empty methods. This release takes this optimisation a step further, by not
240calling any C<DESTROY> method that begins with an C<return> statement.
241This can be useful for destructors that are only used for debugging:
242
243 use constant DEBUG => 1;
244 sub DESTROY { return unless DEBUG; ... }
245
246Constant-folding will reduce the first statement to C<return;> if DEBUG is
247set to 0, triggering this optimisation.
6d110ad0 248
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249=item *
250
251Assign to a variable that holds a typeglob or copy-on-write scalar is now
252much faster. Previously the typeglob would be stringified or the
253copy-on-write scalar would be copied before being clobbered.
254
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255=item *
256
257Assignment to a substring in void context is now more than twice its
258previous speed. Instead of creating and returning a special lvalue scalar
259that is then assigned to, C<substr> modifies the original string itself.
260
e3c71926 261=back
6d110ad0 262
e3c71926 263=head1 Modules and Pragmata
6d110ad0 264
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265XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
266go here. If Module::CoreList is updated, generate an initial draft of the
267following sections using F<Porting/corelist-perldelta.pl>, which prints stub
268entries to STDOUT. Results can be pasted in place of the '=head2' entries
269below. A paragraph summary for important changes should then be added by hand.
270In an ideal world, dual-life modules would have a F<Changes> file that could be
271cribbed.
272
273[ Within each section, list entries as a =item entry ]
274
e3c71926 275=head2 New Modules and Pragmata
6d110ad0 276
e3c71926 277=over 4
6d110ad0
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278
279=item *
280
0aaeb177 281XXX
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282
283=back
284
e3c71926 285=head2 Updated Modules and Pragmata
6d110ad0 286
e3c71926 287=over 4
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288
289=item *
290
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291L<Archive::Tar> has been upgraded from version 1.80 to version 1.82.
292
293Adjustments to handle files >8gb (>0777777777777 octal) and a feature to
294return the MD5SUM of files in the archive.
a3f52e2e 295
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296=item *
297
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298L<AutoLoader> has been upgraded from version 5.71 to version 5.72.
299
300=item *
301
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302L<B::Debug> has been upgraded from version 1.16 to version 1.17.
303
304=item *
305
be4a9ab3 306L<B::Deparse> has been upgraded from version 1.09 to version 1.10.
679b54e7 307
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308Various constructs that used to be deparsed incorrectly have been fixed:
309
310=over
311
312=item C<sort(foo(bar))>
313
314C<sort foo(bar)>, how it used to deparse, makes foo the sort routine,
315rather than a regular function call.
316
317=item Keys and values in C<%^H>
318
319Undefined values in the hint hash were being deparsed as empty strings.
320Whenever the hint hash changed, all undefined values, even those
321unmodified, were being printed.
322
323Special characters, such as quotation marks, were not being escaped
324properly.
325
326Some values used to be omitted if, for instance, a key was the same as a
327previous value and vice versa.
328
329=item "method BLOCK" syntax
330
331C<method { $expr }> used to be deparsed as something like
332C<< do{ $expr }->method >>, but the latter puts the $expr in scalar
333context, whereas the former puts in list context.
334
335=item C<do +{}> and C<do({})>
336
337These are both variants of do-file syntax, but were being deparsed as
338do-blocks.
339
340=item Keywords that do not follow the llafr
341
342Keywords like C<return> and C<last> that do not follow the
343looks-like-a-function rule are now deparsed correctly with parentheses in
344the right place.
345
346Similarly, C<not>, which I<does> follow the llafr, was being deparsed as
347though it does not.
348
349=item C<=~>
350
351In various cases, B::Deparse started adding a spurious C<$_ =~> before the
352right-hand side in Perl 5.14; e.g., C<< "" =~ <$a> >> would become
353C<< "" =~ ($_ =~ <$a>) >>.
354
355=item C<open local *FH>
356
357C<open>, C<pipe> and other functions that autovivify handles used to omit
358C<local *> from C<local *FH>.
359
360=item Negated single-letter subroutine calls
361
362Negated subroutine calls like C<- f()> and C<-(f())> were being deparsed
363as file test operators.
364
365=item C<&{&}>
366
367C<&{&}> and C<& &>, which are calls to the subroutine named "&", believe it
368or not, were being deparsed as C<&&>.
369
370=back
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371
372=item *
373
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374L<Carp> has been upgraded from version 1.23 to version 1.24.
375
376It now tacks the last-accessed filehandle and line number on to the end of
377the error message, just like C<die> [perl #96672].
378
379=item *
380
9505dd85 381L<Compress::Raw::Zlib> has been upgraded from version 2.042 to version 2.045.
87b9431e 382
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383=item *
384
6475ddc2 385L<Compress::Raw::Bzip2> has been upgraded from version 2.042 to version 2.045.
7e700369 386
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387=item *
388
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389L<CPAN::Meta::YAML> has been upgraded from version 0.004 to version 0.005.
390
391=item *
392
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393L<CPANPLUS> has been upgraded from version 0.9112 to version 0.9113.
394
395=item *
396
be4a9ab3 397L<Data::Dumper> has been upgraded from version 2.134 to version 2.135.
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398
399The XS implementation has been updated to account for the Unicode symbol
400changes in Perl 5.15.4. It also knows how to output typeglobs with nulls
401in their names.
402
403=item *
404
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405L<Digest::SHA> has been upgraded from version 5.63 to version 5.70.
406
407Added BITS mode to addfile method and shasum which makes partial-byte inputs
408now possible via files/STDIN and allows shasum to check all 8074 NIST Msg vectors,
409where previously special programming was required to do this.
410
411=item *
412
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413L<Exporter> has been upgraded from version 5.65 to version 5.66.
414
415It no longer tries to localise C<$_> unnecessarily.
416
417=item *
418
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419L<ExtUtils::ParseXS> has been upgraded from version 3.05 to version 3.07.
420
421=item *
422
090349ce 423L<IO::Compress::Base> has been upgraded from version 2.042 to version 2.045.
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424
425Added zipdetails utility.
dc7edc5c 426
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427=item *
428
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429L<Locale::Codes> has been upgraded from version 3.18 to version 3.20.
430
431The code2XXX, XXX2code, all_XXX_codes, and all_XXX_names functions now support retired codes.
432All codesets may be specified by a constant or by their name now. Previously,
433they were specified only by a constant.
434The alias_code function exists for backward compatibility. It has been replaced by rename_country_code.
435The alias_code function will be removed sometime after September, 2013.
436All work is now done in the central module (Locale::Codes). Previously, some was still done in the
437wrapper modules (Locale::Codes::*) but that is gone now.
438Added Language Family codes (langfam) as defined in ISO 639-5.
439
440=item *
441
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442L<Module::Loaded> has been uprgaded from version 0.06 to version 0.08.
443
444=item *
445
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446L<Pod::LaTeX> has been upgraded from version 0.59 to version 0.60.
447
448Added another LaTeX escape: --- => -{}-{}-
449
450Pod::LaTeX doesn't handle -- in PODs specially, passing it directly to
451LaTeX, which then proceeds to replace it with a single -. This patch
452replaces ----- with -{}-{}-{}-{}-
453
454=item *
455
be4a9ab3 456L<POSIX> has been upgraded from version 1.26 to version 1.27.
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457
458It no longer produces a "Constant subroutine TCSANOW redefined" warning on
459Windows.
460
461XXX When did it start producing that warning? Was it post-5.15.5? Even if
462it was not, adding a note will help whoever compiles perl5160delta.
463
464=item *
465
37b1de1b 466L<Socket> has been upgraded from version 1.94_02 to version 1.97.
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467
468=item *
469
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470L<threads> has been upgraded from version 1.85 to version 1.86.
471
472=item *
473
65ae8d99 474L<Unicode::Collate> has been upgraded from version 0.85 to version 0.87.
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475
476Tailored compatibility ideographs as well as unified ideographs for
477the locales: ja, ko, zh__big5han, zh__gb2312han, zh__pinyin, zh__stroke.
478
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479Now Locale/*.pl files are searched in @INC.
480
a3e88ad7
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481=item *
482
be4a9ab3 483L<UNIVERSAL> has been upgraded from version 1.10 to version 1.11.
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484
485Documentation change clarifies return values from UNIVERSAL::VERSION.
486
0aaeb177 487=back
6138a722 488
0aaeb177 489=head2 Removed Modules and Pragmata
6138a722 490
0aaeb177 491=over 4
be539103 492
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493=item *
494
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495Changing the case of a UTF-8 encoded string under C<use locale> now
496gives better, but still imperfect, results. Previously, such a string
497would entirely lose locale semantics and silently be treated as Unicode.
498Now, the code points that are less than 256 are treated with locale
499rules, while those above 255 are, of course, treated as Unicode. See
500L<perlfunc/lc> for more details, including the deficiencies of this
501scheme.
a3f52e2e 502
0aaeb177 503=back
a3f52e2e 504
0aaeb177 505=head1 Documentation
a3f52e2e 506
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507XXX Changes to files in F<pod/> go here. Consider grouping entries by
508file and be sure to link to the appropriate page, e.g. L<perlfunc>.
a3f52e2e 509
0aaeb177 510=head2 New Documentation
ad32999b 511
0aaeb177 512XXX Changes which create B<new> files in F<pod/> go here.
ad32999b 513
0aaeb177 514=head3 L<XXX>
ad32999b 515
0aaeb177 516XXX Description of the purpose of the new file here
6138a722 517
0aaeb177 518=head2 Changes to Existing Documentation
6138a722 519
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520XXX Changes which significantly change existing files in F<pod/> go here.
521However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
522section.
a47fb3fe 523
7687d286 524=head3 L<perlsec/Laundering and Detecting Tainted Data>
a47fb3fe 525
0aaeb177 526=over 4
7ef25837 527
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528=item *
529
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530The example function for checking for taintedness contained a subtle
531error. C<$@> needs to be localized to prevent its changing this
532global's value outside the function. The preferred method to check for
533this, though, remains to use L<Scalar::Util/tainted>.
6d110ad0
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534
535=back
536
e3c71926
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537=head1 Diagnostics
538
539The following additions or changes have been made to diagnostic output,
540including warnings and fatal error messages. For the complete list of
541diagnostic messages, see L<perldiag>.
6d110ad0 542
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543XXX New or changed warnings emitted by the core's C<C> code go here. Also
544include any changes in L<perldiag> that reconcile it to the C<C> code.
6138a722 545
0aaeb177
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546[ Within each section, list entries as a =item entry that links to perldiag,
547 e.g.
6138a722 548
0aaeb177 549 =item *
6138a722 550
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551 L<Invalid version object|perldiag/"Invalid version object">
552]
6138a722 553
0aaeb177 554=head2 New Diagnostics
828d6195 555
0aaeb177 556XXX Newly added diagnostic messages go here
83307084 557
0aaeb177 558=head3 New Errors
d39de893 559
3432e5a1 560=over 4
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561
562=item *
563
0aaeb177 564XXX L<message|perldiag/"message">
6138a722 565
e3c71926 566=back
7b8e5ef0 567
0aaeb177 568=head3 New Warnings
91710846 569
e3c71926 570=over 4
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571
572=item *
573
0aaeb177 574XXX L<message|perldiag/"message">
f81e39ef 575
e3c71926 576=back
a2fa999d 577
0aaeb177
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578=head2 Changes to Existing Diagnostics
579
580XXX Changes (i.e. rewording) of diagnostic messages go here
bd65daab 581
e3c71926 582=over 4
bd65daab 583
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584=item *
585
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586Redefinition warnings for constant subroutines used to be mandatory, even
587occurring under C<no warnings>. Now they respect the L<warnings> pragma.
b420b12a 588
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589=item *
590
591The "Attempt to free non-existent shared string" has had the spelling of
592"non-existent" corrected to "nonexistent". It was already listed with the
593correct spelling in L<perldiag>.
594
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595=item *
596
597The 'Use of "foo" without parentheses is ambiguous' warning has been
598extended to apply also to user-defined subroutines with a (;$) prototype,
599and not just to built-in functions.
600
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601=item *
602
603The error messages for using C<default> and C<when> outside of a
604topicalizer have been standardised to match the messages for C<continue>
605and loop controls. They now read 'Can't "default" outside a topicalizer'
606and 'Can't "when" outside a topicalizer'. They both used to be 'Can't use
607when() outside a topicalizer' [perl #91514].
608
3432e5a1 609=back
b420b12a 610
0aaeb177 611=head1 Utility Changes
9cfd094e 612
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613XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go
614here. Most of these are built within the directories F<utils> and F<x2p>.
95f7e41f 615
0aaeb177
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616[ List utility changes as a =head3 entry for each utility and =item
617entries for each change
618Use L<XXX> with program names to get proper documentation linking. ]
95f7e41f 619
08ad9465 620=head3 L<zipdetails>
d6cf2367 621
e3c71926 622=over 4
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623
624=item *
625
08ad9465
CBW
626L<zipdetails> displays information about the internal record structure of the zip file.
627It is not concerned with displaying any details of the compressed data stored in the zip file.
b53e16ae 628
3432e5a1 629=back
60092ce4 630
0aaeb177
SH
631=head1 Configuration and Compilation
632
633XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
634go here. Any other changes to the Perl build process should be listed here.
635However, any platform-specific changes should be listed in the
636L</Platform Support> section, instead.
637
638[ List changes as a =item entry ].
309aab3a 639
e3c71926 640=over 4
b53e16ae
FC
641
642=item *
643
60f0ee9d
NC
644F<pod/roffitall> is now build by F<pod/buildtoc>, instead of being shipped
645with the distribution. Its list of manpages is now generated (and therefore
646current). See also RT #103202 for an unresolved related issue.
a3f52e2e 647
61f966e7
FC
648=item *
649
650Perl 5.15.5 had a bug in its installation script, which did not install
651F<unicore/Name.pm>. This has been corrected [perl #104226].
652
653XXX Is that Perl version correct? Is the file path correct?
654
f4912a50
DR
655=item *
656
657The -Dusesitecustomize and -Duserelocatableinc options now work together
658properly.
659
0aaeb177 660=back
a3f52e2e 661
0aaeb177 662=head1 Testing
a3f52e2e 663
0aaeb177
SH
664XXX Any significant changes to the testing of a freshly built perl should be
665listed here. Changes which create B<new> files in F<t/> go here as do any
666large changes to the testing harness (e.g. when parallel testing was added).
667Changes to existing files in F<t/> aren't worth summarising, although the bugs
668that they represent may be covered elsewhere.
a3f52e2e 669
0aaeb177 670[ List each test improvement as a =item entry ]
a3f52e2e 671
0aaeb177 672=over 4
a3f52e2e
FC
673
674=item *
675
d1fb015b
FC
676The F<substr.t> and F<substr_thr.t> scripts for testing C<substr> have been
677moved under F<t/op/>, where they were originally. They had been moved
678under F<t/re/> along with the substitution tests when that directory was
679created.
a3f52e2e 680
0aaeb177 681=back
a3f52e2e 682
0aaeb177 683=head1 Platform Support
a3f52e2e 684
0aaeb177 685XXX Any changes to platform support should be listed in the sections below.
a3f52e2e 686
0aaeb177
SH
687[ Within the sections, list each platform as a =item entry with specific
688changes as paragraphs below it. ]
a3f52e2e 689
0aaeb177 690=head2 New Platforms
a3f52e2e 691
0aaeb177
SH
692XXX List any platforms that this version of perl compiles on, that previous
693versions did not. These will either be enabled by new files in the F<hints/>
694directories, or new subdirectories and F<README> files at the top level of the
695source tree.
a3f52e2e 696
0aaeb177 697=over 4
a3f52e2e 698
0aaeb177 699=item XXX-some-platform
a3f52e2e 700
0aaeb177 701XXX
a3f52e2e 702
0aaeb177 703=back
a3f52e2e 704
0aaeb177 705=head2 Discontinued Platforms
ca955add 706
0aaeb177 707XXX List any platforms that this version of perl no longer compiles on.
bbdd8bad 708
0aaeb177 709=over 4
bbdd8bad 710
0aaeb177 711=item XXX-some-platform
ad32999b 712
0aaeb177 713XXX
ad32999b 714
0aaeb177 715=back
ad32999b 716
0aaeb177 717=head2 Platform-Specific Notes
ad32999b 718
0aaeb177
SH
719XXX List any changes for specific platforms. This could include configuration
720and compilation changes or changes in portability/compatibility. However,
721changes within modules for platforms should generally be listed in the
722L</Modules and Pragmata> section.
ad32999b 723
f4912a50
DR
724=head3 VMS
725
0aaeb177 726=over 4
ad32999b 727
f4912a50 728=item *
ad32999b 729
a3ef9f5c
CB
730A link-time error on VMS versions without C<symlink> support was
731introduced in 5.15.1, but has now been corrected.
f4912a50
DR
732
733=item *
734
a3ef9f5c
CB
735Explicit support for VMS versions prior to v7.0 and DEC C versions prior
736to v6.0 has been removed.
737
738=item *
739
740Since Perl 5.10.1, the home-grown C<stat> wrapper has been unable to
741distinguish between a directory name containing an underscore and an
742otherwise-identical filename containing a dot in the same position
743(e.g., t/test_pl as a directory and t/test.pl as a file). This problem
744has been corrected.
c15f899f 745
7f28d7ed 746=back
ad32999b 747
0aaeb177 748=head1 Internal Changes
ad32999b 749
0aaeb177
SH
750XXX Changes which affect the interface available to C<XS> code go here.
751Other significant internal changes for future core maintainers should
752be noted as well.
ad32999b 753
0aaeb177 754[ List each change as a =item entry ]
ad32999b 755
0aaeb177 756=over 4
ad32999b 757
3973654e
FC
758=item *
759
0aaeb177 760XXX
3973654e 761
0aaeb177 762=back
cca38fda 763
0aaeb177 764=head1 Selected Bug Fixes
9c7c1651 765
0aaeb177
SH
766XXX Important bug fixes in the core language are summarised here.
767Bug fixes in files in F<ext/> and F<lib/> are best summarised in
768L</Modules and Pragmata>.
9c7c1651 769
0aaeb177 770[ List each fix as a =item entry ]
fce59cd4 771
0aaeb177 772=over 4
fce59cd4 773
b9e83cd1
FC
774=item *
775
7402016d
AB
776RT #78266: The regex engine has been leaking memory when accessing
777named captures that weren't matched as part of a regex ever since 5.10
778when they were introduced, e.g. this would consume over a hundred MB
779of memory:
780
e46b6a32
FC
781 for (1..10_000_000) {
782 if ("foo" =~ /(foo|(?<capture>bar))?/) {
783 my $capture = $+{capture}
784 }
785 }
786 system "ps -o rss $$"'
7402016d
AB
787
788=item *
789
541cb22c
FC
790A constant subroutine assigned to a glob whose name contains a null will no
791longer cause extra globs to pop into existence when the constant is
792referenced under its new name.
b9e83cd1 793
679b54e7
FC
794=item *
795
796C<sort> was not treating C<sub {}> and C<sub {()}> as equivalent when such
797a sub was provided as the comparison routine. It used to croak on
798C<sub {()}>.
799
800=item *
801
802Subroutines from the C<autouse> namespace are once more exempt from
803redefinition warnings. This used to work in 5.005, but was broken in 5.6
804for most subroutines. For subs created via XS that redefine subroutines
805from the C<autouse> package, this stopped working in 5.10.
806
807=item *
808
809New XSUBs now produce redefinition warnings if they overwrite existing
810subs, as they did in 5.8.x. (The C<autouse> logic was reversed in 5.10-14.
811Only subroutines from the C<autouse> namespace would warn when clobbered.)
812
813=item *
814
815Redefinition warnings triggered by the creation of XSUBs now respect
816Unicode glob names, instead of using the internal representation. This was
817missed in 5.15.4, partly because this warning was so hard to trigger. (See
818the previous item.)
819
820=item *
821
822C<newCONSTSUB> used to use compile-time warning hints, instead of run-time
823hints. The following code should never produce a redefinition warning, but
824it used to, if C<newCONSTSUB> redefine and existing subroutine:
825
826 use warnings;
827 BEGIN {
828 no warnings;
829 some_XS_function_that_calls_new_CONSTSUB();
830 }
831
61f966e7
FC
832=item *
833
834Redefinition warnings for constant subroutines are on by default (what are
835known as severe warnings in L<perldiag>). This was only the case when it
836was a glob assignment or declaration of a Perl subroutine that caused the
837warning. If the creation of XSUBs triggered the warning, it was not a
838default warning. This has been corrected.
839
840=item *
841
842The internal check to see whether a redefinition warning should occur used
843to emit "uninitialized" warnings in cases like this:
844
845 use warnings "uninitialized";
846 use constant {u=>undef,v=>undef};
847 sub foo(){u} sub foo(){v}
848
849=item *
850
851A bug fix in Perl 5.14 introduced a new bug, causing "uninitialized"
852warnings to report the wrong variable if the operator in question has
853two operands and one is C<%{...}> or C<@{...}>. This has been fixed
854[perl #103766].
855
856=item *
857
858C<< version->new("version") >> and C<printf "%vd", "version"> no longer
859crash [perl #102586].
860
d1fb015b
FC
861=item *
862
863C<$tied =~ y/a/b/>, C<chop $tied> and C<chomp $tied> now call FETCH just
864once when $tied holds a reference.
865
866=item *
867
868Four-argument C<select> now always calls FETCH on tied arguments. It used
869to skip the call if the tied argument happened to hold C<undef> or a
870typeglob.
871
872=item *
873
874Four-argument C<select> no longer produces its "Non-string passed as
875bitmask" warning on tied or tainted variables that are strings.
876
877=item *
878
879C<sysread> now always calls FETCH on the buffer passed to it if it is tied.
880It used to skip the call if the tied variable happened to hold a typeglob.
881
882=item *
883
884C<< $tied .= <> >> now calls FETCH once on C<$tied>. It used to call it
885multiple times if the last value assigned to or returned from the tied
886variable was anything other than a string or typeglob.
887
66008486
FC
888=item *
889
890The C<evalbytes> keyword added in 5.15.5 was respecting C<use utf8>
891declarations from the outer scope, when it should have been ignoring them.
892
7e7629fa
FC
893=item *
894
895C<goto &func> no longers crashes, but produces an error message, when the
896unwinding of the current subroutine's scope fires a destructor that
897undefines the subroutine being "goneto" [perl #99850].
898
73512201
DG
899=item *
900
901Arithmetic assignment (C<$left += $right>) involving overloaded objects that
902rely on the 'nomethod' override no longer segfault when the left operand is not
903overloaded.
904
a1f0e6ed
FC
905=item *
906
907Assigning C<__PACKAGE__> or any other shared hash key scalar to a stash
908element no longer causes a double free. Regardless of this change, the
909results of such assignments are still undefined.
910
911=item *
912
913Creating a C<UNIVERSAL::AUTOLOAD> sub no longer stops C<%+>, C<%-> and
914C<%!> from working some of the time [perl #105024].
915
ad790500
FC
916=item *
917
918Assigning C<__PACKAGE__> or another shared hash key string to a variable no
919longer stops that variable from being tied if it happens to be a PVMG or
920PVLV internally.
921
6d91e957
KW
922=item *
923
924When presented with malformed UTF-8 input, the XS-callable functions
925C<is_utf8_string()>, C<is_utf8_string_loc()>, and
926C<is_utf8_string_loclen()> could read beyond the end of the input
927string by up to 12 bytes. This no longer happens. [perl #32080].
928However, currently, C<is_utf8_char()> still has this defect,
929see L</is_utf8_char()> above.
930
d6b99bf4
FC
931=item *
932
933Doing a substitution on a tied variable returning a copy-on-write scalar
934used to cause an assertion failure or an "Attempt to free nonexistent
935shared string" warning.
936
937=item *
938
939A change in perl 5.15.4 caused C<caller()> to produce malloc errors and a
940crash with Perl's own malloc, and possibly with other malloc
941implementations, too [perl #104034].
942
943=item *
944
945A bug fix in 5.15.5 could sometimes result in assertion failures under
946debugging builds of perl for certain syntax errors in C<eval>, such as
947C<eval(q|""!=!~//|);>
948
8aade7da
DR
949=item *
950
951The "c [line num]" debugger command was broken by other debugger changes
5dd80d85 952release in 5.15.3. This is now fixed.
8aade7da 953
c7b728ca
SF
954=item *
955
956Breakpoints were not properly restored after a debugger restart using the
5dd80d85
FC
957"R" command. This was broken in 5.15.3. This is now fixed.
958
959=item *
960
961The debugger prompt did not display the current line in. This was broken
962in 5.15.3. This is now fixed.
c7b728ca
SF
963
964=item *
965
5dd80d85
FC
966Class method calls still suffered from the Unicode bug with Latin-1 package
967names. This was missed in the Unicode package name cleanup in 5.15.4
968[perl #105922].
c7b728ca 969
0aaeb177 970=back
bf19b80e 971
0aaeb177 972=head1 Known Problems
bf19b80e 973
0aaeb177
SH
974XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
975tests that had to be C<TODO>ed for the release would be noted here, unless
976they were specific to a particular platform (see below).
65b66aa9 977
0aaeb177
SH
978This is a list of some significant unfixed bugs, which are regressions
979from either 5.XXX.XXX or 5.XXX.XXX.
65b66aa9 980
0aaeb177 981[ List each fix as a =item entry ]
b53e16ae 982
0aaeb177 983=over 4
b53e16ae 984
7c864bb3
VP
985=item *
986
0aaeb177 987XXX
7c864bb3 988
63ac71b9 989=back
bbc28bfc 990
0aaeb177 991=head1 Obituary
8fe05716 992
0aaeb177
SH
993XXX If any significant core contributor has died, we've added a short obituary
994here.
8fe05716 995
0aaeb177 996=head1 Acknowledgements
8fe05716 997
0aaeb177 998XXX Generate this with:
8fe05716 999
0aaeb177 1000 perl Porting/acknowledgements.pl v5.15.5..HEAD
29cf780c 1001
44691e6f
AB
1002=head1 Reporting Bugs
1003
1004If you find what you think is a bug, you might check the articles
34dc2ec0 1005recently posted to the comp.lang.perl.misc newsgroup and the perl
44691e6f
AB
1006bug database at http://rt.perl.org/perlbug/ . There may also be
1007information at http://www.perl.org/ , the Perl Home Page.
1008
1009If you believe you have an unreported bug, please run the L<perlbug>
1010program included with your release. Be sure to trim your bug down
1011to a tiny but sufficient test case. Your bug report, along with the
1012output of C<perl -V>, will be sent off to perlbug@perl.org to be
1013analysed by the Perl porting team.
1014
1015If the bug you are reporting has security implications, which make it
1016inappropriate to send to a publicly archived mailing list, then please send
34dc2ec0 1017it to perl5-security-report@perl.org. This points to a closed subscription
b4707b2a
FC
1018unarchived mailing list, which includes
1019all the core committers, who will be able
44691e6f
AB
1020to help assess the impact of issues, figure out a resolution, and help
1021co-ordinate the release of patches to mitigate or fix the problem across all
34dc2ec0
DM
1022platforms on which Perl is supported. Please only use this address for
1023security issues in the Perl core, not for modules independently
44691e6f
AB
1024distributed on CPAN.
1025
1026=head1 SEE ALSO
1027
1028The F<Changes> file for an explanation of how to view exhaustive details
1029on what changed.
1030
1031The F<INSTALL> file for how to build Perl.
1032
1033The F<README> file for general stuff.
1034
1035The F<Artistic> and F<Copying> files for copyright information.
1036
1037=cut