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44691e6f AB |
1 | =encoding utf8 |
2 | ||
3 | =head1 NAME | |
4 | ||
86372193 A |
5 | [ this is a template for a new perldelta file. Any text flagged as XXX needs |
6 | to be processed before release. ] | |
7 | ||
8 | perldelta - what is new for perl v5.21.6 | |
c68523cb | 9 | |
238894db | 10 | =head1 DESCRIPTION |
c68523cb | 11 | |
86372193 | 12 | This document describes differences between the 5.21.5 release and the 5.21.6 |
238894db | 13 | release. |
c68523cb | 14 | |
86372193 A |
15 | If you are upgrading from an earlier release such as 5.21.4, first read |
16 | L<perl5215delta>, which describes differences between 5.21.4 and 5.21.5. | |
8435afd1 | 17 | |
86372193 | 18 | =head1 Notice |
5cfa0642 | 19 | |
86372193 | 20 | XXX Any important notices here |
4cad5dc8 | 21 | |
86372193 | 22 | =head1 Core Enhancements |
4cad5dc8 | 23 | |
86372193 A |
24 | XXX New core language features go here. Summarize user-visible core language |
25 | enhancements. Particularly prominent performance optimisations could go | |
26 | here, but most should go in the L</Performance Enhancements> section. | |
a5591204 | 27 | |
86372193 | 28 | [ List each enhancement as a =head2 entry ] |
a5591204 | 29 | |
518159a1 TC |
30 | =head2 List form of pipe open implemented for Win32 |
31 | ||
32 | The list form of pipe: | |
33 | ||
34 | open my $fh, "-|", "program", @arguments; | |
35 | ||
36 | is now implemented on Win32. It has the same limitations as C<system | |
37 | LIST> on Win32, since the Win32 API doesn't accept program arguments | |
38 | as a list. | |
39 | ||
fe609065 FC |
40 | =head2 Assignment to list repetition |
41 | ||
42 | C<(...) x ...> can now be used within a list that is assigned to, as long | |
43 | as the left-hand side is a valid lvalue. This allows C<(undef,undef,$foo) | |
44 | = that_function()> to be written as C<((undef)x2, $foo) = that_function()>. | |
45 | ||
295f7815 FC |
46 | =head2 C<close> now sets C<$!> |
47 | ||
48 | When an I/O error occurs, the fact that there has been an error is recorded | |
49 | in the handle. C<close> returns false for such a handle. Previously, the | |
50 | value of C<$!> would be untouched by C<close>, so the common convention of | |
51 | writing C<close $fh or die $!> did not work reliably. Now the handle | |
52 | records the value of C<$!>, too, and C<close> restores it. | |
53 | ||
86372193 | 54 | =head1 Security |
a5591204 | 55 | |
86372193 A |
56 | XXX Any security-related notices go here. In particular, any security |
57 | vulnerabilities closed should be noted here rather than in the | |
58 | L</Selected Bug Fixes> section. | |
a5591204 | 59 | |
86372193 | 60 | [ List each security issue as a =head2 entry ] |
a5591204 | 61 | |
86372193 | 62 | =head1 Incompatible Changes |
a5591204 | 63 | |
86372193 | 64 | XXX For a release on a stable branch, this section aspires to be: |
a5591204 | 65 | |
86372193 A |
66 | There are no changes intentionally incompatible with 5.XXX.XXX |
67 | If any exist, they are bugs, and we request that you submit a | |
68 | report. See L</Reporting Bugs> below. | |
b15c1b56 | 69 | |
86372193 | 70 | [ List each incompatible change as a =head2 entry ] |
b15c1b56 | 71 | |
86372193 | 72 | =head1 Deprecations |
bb8c7e27 | 73 | |
86372193 | 74 | XXX Any deprecated features, syntax, modules etc. should be listed here. |
bb8c7e27 | 75 | |
86372193 | 76 | =head2 Module removals |
bb8c7e27 | 77 | |
86372193 | 78 | XXX Remove this section if inapplicable. |
9a88d663 | 79 | |
86372193 A |
80 | The following modules will be removed from the core distribution in a |
81 | future release, and will at that time need to be installed from CPAN. | |
82 | Distributions on CPAN which require these modules will need to list them as | |
83 | prerequisites. | |
9a88d663 | 84 | |
86372193 A |
85 | The core versions of these modules will now issue C<"deprecated">-category |
86 | warnings to alert you to this fact. To silence these deprecation warnings, | |
87 | install the modules in question from CPAN. | |
5cfa0642 | 88 | |
86372193 A |
89 | Note that these are (with rare exceptions) fine modules that you are encouraged |
90 | to continue to use. Their disinclusion from core primarily hinges on their | |
91 | necessity to bootstrapping a fully functional, CPAN-capable Perl installation, | |
92 | not usually on concerns over their design. | |
ba474e87 | 93 | |
86372193 | 94 | =over |
8435afd1 | 95 | |
86372193 | 96 | =item XXX |
d0ab07ee | 97 | |
86372193 A |
98 | XXX Note that deprecated modules should be listed here even if they are listed |
99 | as an updated module in the L</Modules and Pragmata> section. | |
cc4d09e1 | 100 | |
86372193 | 101 | =back |
cc4d09e1 | 102 | |
86372193 | 103 | [ List each other deprecation as a =head2 entry ] |
8435afd1 | 104 | |
4475d0d2 KW |
105 | =head2 Use of non-graphic characters in single-character variable names |
106 | ||
107 | The syntax for single-character variable names is more lenient than | |
108 | for longer variable names, allowing the one-character name to be a | |
109 | punctuation character or even invisible (a non-graphic). Perl v5.20 | |
110 | deprecated the ASCII-range controls as such a name. Now, all | |
111 | non-graphic characters that formerly were allowed are deprecated. | |
112 | The practical effect of this occurs only when not under C<S<"use | |
113 | utf8">>, and affects just the C1 controls (code points 0x80 through | |
114 | 0xFF), NO-BREAK SPACE, and SOFT HYPHEN. | |
115 | ||
8c8d6154 | 116 | =head1 Performance Enhancements |
5cfa0642 | 117 | |
86372193 A |
118 | XXX Changes which enhance performance without changing behaviour go here. |
119 | There may well be none in a stable release. | |
5cfa0642 | 120 | |
86372193 | 121 | [ List each enhancement as a =item entry ] |
8435afd1 | 122 | |
86372193 | 123 | =over 4 |
5cfa0642 | 124 | |
5b306eef DD |
125 | =item * |
126 | ||
25a8e2be FC |
127 | C<(...)x1>, C<("constant")x0> and C<($scalar)x0> are now optimised in list |
128 | context. If the right-hand argument is a constant 1, the repetition | |
129 | operator disappears. If the right-hand argument is a constant 0, the whole | |
130 | expressions is optimised to the empty list, so long as the left-hand | |
131 | argument is a simple scalar or constant. C<(foo())x0> is not optimised. | |
5b306eef | 132 | |
ef7051ba FC |
133 | =item * |
134 | ||
135 | C<substr> assignment is now optimised into 4-argument C<substr> at the end | |
136 | of a subroutine (or as the argument to C<return>). Previously, this | |
137 | optimisation only happened in void context. | |
138 | ||
86372193 | 139 | =back |
357205d5 | 140 | |
86372193 | 141 | =head1 Modules and Pragmata |
357205d5 | 142 | |
86372193 A |
143 | XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/> |
144 | go here. If Module::CoreList is updated, generate an initial draft of the | |
145 | following sections using F<Porting/corelist-perldelta.pl>. A paragraph summary | |
146 | for important changes should then be added by hand. In an ideal world, | |
147 | dual-life modules would have a F<Changes> file that could be cribbed. | |
f704f251 | 148 | |
86372193 | 149 | [ Within each section, list entries as a =item entry ] |
f704f251 | 150 | |
86372193 | 151 | =head2 New Modules and Pragmata |
0cb3abac | 152 | |
86372193 | 153 | =over 4 |
0cb3abac | 154 | |
deec1830 FC |
155 | =item * |
156 | ||
86372193 | 157 | XXX |
deec1830 | 158 | |
8c8d6154 | 159 | =back |
d0ab07ee | 160 | |
8c8d6154 | 161 | =head2 Updated Modules and Pragmata |
d99849ae | 162 | |
39c4a6cf | 163 | =over 4 |
d99849ae | 164 | |
ff433f2d PM |
165 | =item * |
166 | ||
15d464c4 FC |
167 | L<B::Deparse> has been upgraded from version 1.29 to 1.30. |
168 | ||
169 | It now deparses C<+sub : attr { ... }> correctly at the start of a | |
170 | statement. Without the initial C<+>, C<sub> would be a statement label. | |
171 | ||
16752205 FC |
172 | C<BEGIN> blocks are now emitted in the right place most of the time, but |
173 | the change unfortunately introduced a regression, in that C<BEGIN> blocks | |
174 | occurring just before the end of the enclosing block may appear below it | |
175 | instead. So this change may need to be reverted if it cannot be fixed | |
176 | before Perl 5.22. [perl #77452] | |
177 | ||
15d464c4 FC |
178 | =item * |
179 | ||
f4e81f96 | 180 | L<DynaLoader> has been upgraded from version 1.27 to 1.28. |
cbfcbc14 | 181 | |
bb6a367a DD |
182 | =item * |
183 | ||
f4e81f96 FC |
184 | L<IO::Socket> has been upgraded from version 1.37 to 1.38. |
185 | ||
186 | Document the limitations of the isconnected() method. [perl #123096] | |
bb6a367a | 187 | |
86372193 | 188 | =back |
f348c3d8 | 189 | |
86372193 | 190 | =head2 Removed Modules and Pragmata |
f348c3d8 | 191 | |
86372193 | 192 | =over 4 |
f348c3d8 A |
193 | |
194 | =item * | |
195 | ||
86372193 | 196 | XXX |
f348c3d8 | 197 | |
86372193 | 198 | =back |
7635ad4d | 199 | |
86372193 | 200 | =head1 Documentation |
7635ad4d | 201 | |
86372193 A |
202 | XXX Changes to files in F<pod/> go here. Consider grouping entries by |
203 | file and be sure to link to the appropriate page, e.g. L<perlfunc>. | |
7635ad4d | 204 | |
86372193 | 205 | =head2 New Documentation |
f348c3d8 | 206 | |
86372193 | 207 | XXX Changes which create B<new> files in F<pod/> go here. |
f348c3d8 | 208 | |
86372193 | 209 | =head3 L<XXX> |
f4eedc6b | 210 | |
86372193 | 211 | XXX Description of the purpose of the new file here |
f4eedc6b | 212 | |
86372193 | 213 | =head2 Changes to Existing Documentation |
f4eedc6b | 214 | |
86372193 A |
215 | XXX Changes which significantly change existing files in F<pod/> go here. |
216 | However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics> | |
217 | section. | |
f348c3d8 | 218 | |
42327f06 | 219 | =head3 L<perldata/Identifier parsing> |
f348c3d8 | 220 | |
86372193 | 221 | =over 4 |
f348c3d8 A |
222 | |
223 | =item * | |
224 | ||
42327f06 KW |
225 | The syntax of single-character variable names has been brought |
226 | up-to-date and more fully explained. | |
f348c3d8 | 227 | |
86372193 | 228 | =back |
f348c3d8 | 229 | |
86372193 | 230 | =head1 Diagnostics |
f348c3d8 | 231 | |
86372193 A |
232 | The following additions or changes have been made to diagnostic output, |
233 | including warnings and fatal error messages. For the complete list of | |
234 | diagnostic messages, see L<perldiag>. | |
f348c3d8 | 235 | |
86372193 A |
236 | XXX New or changed warnings emitted by the core's C<C> code go here. Also |
237 | include any changes in L<perldiag> that reconcile it to the C<C> code. | |
f348c3d8 | 238 | |
86372193 | 239 | =head2 New Diagnostics |
f348c3d8 | 240 | |
86372193 A |
241 | XXX Newly added diagnostic messages go under here, separated into New Errors |
242 | and New Warnings | |
f348c3d8 | 243 | |
86372193 | 244 | =head3 New Errors |
84d03adf | 245 | |
86372193 | 246 | =over 4 |
ff433f2d | 247 | |
4cd408ba TC |
248 | =item * |
249 | ||
86372193 | 250 | XXX L<message|perldiag/"message"> |
f348c3d8 | 251 | |
86372193 | 252 | =back |
f348c3d8 | 253 | |
86372193 | 254 | =head3 New Warnings |
f4eedc6b | 255 | |
86372193 | 256 | =over 4 |
f4eedc6b DD |
257 | |
258 | =item * | |
259 | ||
4475d0d2 | 260 | L<Use of literal non-graphic characters in variable names is deprecated|perldiag/"Use of literal non-graphic characters in variable names is deprecated"> |
f348c3d8 | 261 | |
ab0b796c KW |
262 | =item * |
263 | ||
8c6180a9 KW |
264 | A new C<locale> warning category has been created, with the following warning |
265 | messages currently in it: | |
266 | ||
267 | =over 4 | |
268 | ||
269 | =item * | |
270 | ||
271 | L<Locale '%s' may not work well.%s|perldiag/Locale '%s' may not work well.%s> | |
272 | ||
273 | =item * | |
274 | ||
ab0b796c KW |
275 | L<Can't do %s("%s") on non-UTF-8 locale; resolved to "%s".|perldiag/Can't do %s("%s") on non-UTF-8 locale; resolved to "%s".> |
276 | ||
86372193 | 277 | =back |
0561e60b | 278 | |
dd200dff FC |
279 | =item * |
280 | ||
281 | L<Warning: unable to close filehandle %s properly: %s|perldiag/"Warning: unable to close filehandle %s properly: %s"> | |
282 | ||
8c6180a9 KW |
283 | =back |
284 | ||
86372193 | 285 | =head2 Changes to Existing Diagnostics |
0561e60b | 286 | |
86372193 | 287 | XXX Changes (i.e. rewording) of diagnostic messages go here |
0561e60b | 288 | |
86372193 | 289 | =over 4 |
4cd408ba | 290 | |
f348c3d8 A |
291 | =item * |
292 | ||
cb3bb329 | 293 | L<Quantifier unexpected on zero-length expression in regex mE<sol>%sE<sol>|perldiag/"Quantifier unexpected on zero-length expression in regex m/%s/">. |
4a328228 FC |
294 | |
295 | This message has had the S<"<-- HERE"> marker removed, as it was always | |
296 | placed at the end of the regular expression, regardless of where the | |
297 | problem actually occurred. [perl #122680] | |
4cd408ba | 298 | |
86372193 | 299 | =back |
40a81b59 | 300 | |
86372193 | 301 | =head1 Utility Changes |
f348c3d8 | 302 | |
86372193 A |
303 | XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go here. |
304 | Most of these are built within the directory F<utils>. | |
f348c3d8 | 305 | |
86372193 A |
306 | [ List utility changes as a =head2 entry for each utility and =item |
307 | entries for each change | |
308 | Use L<XXX> with program names to get proper documentation linking. ] | |
f348c3d8 | 309 | |
86372193 | 310 | =head2 L<XXX> |
f348c3d8 | 311 | |
86372193 | 312 | =over 4 |
f348c3d8 A |
313 | |
314 | =item * | |
315 | ||
86372193 | 316 | XXX |
40a81b59 | 317 | |
13900f93 | 318 | =back |
aac7f82f | 319 | |
86372193 | 320 | =head1 Configuration and Compilation |
2a395b86 | 321 | |
86372193 A |
322 | XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools |
323 | go here. Any other changes to the Perl build process should be listed here. | |
324 | However, any platform-specific changes should be listed in the | |
325 | L</Platform Support> section, instead. | |
8435afd1 | 326 | |
86372193 | 327 | [ List changes as a =item entry ]. |
8435afd1 SH |
328 | |
329 | =over 4 | |
2a395b86 | 330 | |
12d22d1f JK |
331 | =item * |
332 | ||
c517e197 | 333 | F<Configure> with C<-Dmksymlinks> should now be faster. [perl #122002] |
12d22d1f | 334 | |
2a395b86 PM |
335 | =back |
336 | ||
86372193 | 337 | =head1 Testing |
2a395b86 | 338 | |
86372193 A |
339 | XXX Any significant changes to the testing of a freshly built perl should be |
340 | listed here. Changes which create B<new> files in F<t/> go here as do any | |
341 | large changes to the testing harness (e.g. when parallel testing was added). | |
342 | Changes to existing files in F<t/> aren't worth summarizing, although the bugs | |
343 | that they represent may be covered elsewhere. | |
2a395b86 | 344 | |
86372193 | 345 | [ List each test improvement as a =item entry ] |
5cfa0642 | 346 | |
8c8d6154 | 347 | =over 4 |
2a395b86 PM |
348 | |
349 | =item * | |
350 | ||
86372193 | 351 | XXX |
bb8c7e27 | 352 | |
86372193 | 353 | =back |
bb8c7e27 | 354 | |
86372193 | 355 | =head1 Platform Support |
bb8c7e27 | 356 | |
86372193 | 357 | XXX Any changes to platform support should be listed in the sections below. |
bb8c7e27 | 358 | |
86372193 A |
359 | [ Within the sections, list each platform as a =item entry with specific |
360 | changes as paragraphs below it. ] | |
2a395b86 | 361 | |
86372193 | 362 | =head2 New Platforms |
6d9b7c7c | 363 | |
86372193 A |
364 | XXX List any platforms that this version of perl compiles on, that previous |
365 | versions did not. These will either be enabled by new files in the F<hints/> | |
366 | directories, or new subdirectories and F<README> files at the top level of the | |
367 | source tree. | |
363d3025 | 368 | |
8c8d6154 | 369 | =over 4 |
334464b3 | 370 | |
86372193 | 371 | =item XXX-some-platform |
334464b3 | 372 | |
86372193 | 373 | XXX |
ef5a9509 | 374 | |
363d3025 FC |
375 | =back |
376 | ||
86372193 A |
377 | =head2 Discontinued Platforms |
378 | ||
379 | XXX List any platforms that this version of perl no longer compiles on. | |
d72cd2eb | 380 | |
0346c3a9 | 381 | =over 4 |
375f5f06 | 382 | |
86372193 | 383 | =item XXX-some-platform |
2884baee | 384 | |
86372193 | 385 | XXX |
6f1a844b | 386 | |
8c8d6154 | 387 | =back |
549ea8d4 | 388 | |
8c8d6154 | 389 | =head2 Platform-Specific Notes |
aa292ef2 | 390 | |
86372193 A |
391 | XXX List any changes for specific platforms. This could include configuration |
392 | and compilation changes or changes in portability/compatibility. However, | |
393 | changes within modules for platforms should generally be listed in the | |
394 | L</Modules and Pragmata> section. | |
395 | ||
8c8d6154 | 396 | =over 4 |
739e9bee | 397 | |
86372193 | 398 | =item XXX-some-platform |
739e9bee | 399 | |
86372193 | 400 | XXX |
b23b2fdb | 401 | |
8c8d6154 | 402 | =back |
b23b2fdb | 403 | |
83b69bfd DD |
404 | =head3 Win32 |
405 | ||
406 | =over 4 | |
407 | ||
408 | =item * | |
409 | ||
410 | In the experimental C<:win32> layer, a crash in C<open> was fixed. Also | |
411 | opening C</dev/null>, which works the Win32 Perl's normal C<:unix> layer, was | |
412 | implemented for C<:win32>. | |
413 | L<[perl #122224]|https://rt.perl.org/Ticket/Display.html?id=122224> | |
414 | ||
13adb056 SH |
415 | =item * |
416 | ||
417 | A new makefile option, C<USE_LONG_DOUBLE>, has been added to the Windows | |
418 | dmake makefile for gcc builds only. Set this to "define" if you want perl to | |
419 | use long doubles to give more accuracy and range for floating point numbers. | |
420 | ||
83b69bfd DD |
421 | =back |
422 | ||
8c8d6154 | 423 | =head1 Internal Changes |
7d15b1a8 | 424 | |
86372193 A |
425 | XXX Changes which affect the interface available to C<XS> code go here. Other |
426 | significant internal changes for future core maintainers should be noted as | |
427 | well. | |
bbca64cf | 428 | |
86372193 | 429 | [ List each change as a =item entry ] |
6ff8f256 | 430 | |
86372193 | 431 | =over 4 |
28482d6c | 432 | |
28a42920 A |
433 | =item * |
434 | ||
f8d5a522 DD |
435 | C<screaminstr> has been removed. Although marked as public API, it is |
436 | undocumented and has no usage in modern perl versions on CPAN Grep. Calling it | |
437 | has been fatal since 5.17.0. | |
28a42920 | 438 | |
d109137e FC |
439 | =item * |
440 | ||
76acbf4f FC |
441 | C<newDEFSVOP>, C<block_start>, C<block_end> and C<intro_my> have been added |
442 | to the API. | |
d109137e | 443 | |
cff8e04e FC |
444 | =item * |
445 | ||
446 | The internal C<convert> function in F<op.c> has been renamed | |
447 | C<op_convert_list> and added to the API. | |
448 | ||
391823f2 FC |
449 | =item * |
450 | ||
451 | C<sv_magic> no longer forbids "ext" magic on read-only values. After all, | |
452 | perl can't know whether the custom magic will modify the SV or not. | |
453 | [perl #123103] | |
454 | ||
8c8d6154 | 455 | =back |
6ff8f256 | 456 | |
8c8d6154 | 457 | =head1 Selected Bug Fixes |
80cc3290 | 458 | |
86372193 A |
459 | XXX Important bug fixes in the core language are summarized here. Bug fixes in |
460 | files in F<ext/> and F<lib/> are best summarized in L</Modules and Pragmata>. | |
13dd5671 | 461 | |
86372193 | 462 | [ List each fix as a =item entry ] |
bdab7676 | 463 | |
86372193 | 464 | =over 4 |
db98db4e | 465 | |
8818afe8 TC |
466 | =item * |
467 | ||
2ad9844a TC |
468 | fchmod() and futimes() now set C<$!> when they fail due to being |
469 | passed a closed file handle. [perl #122703] | |
bb8c7e27 | 470 | |
9ee757be KW |
471 | =item * |
472 | ||
473 | Perl now comes with a corrected Unicode 7.0 for the erratum issued on | |
474 | October 21, 2014 (see L<http://www.unicode.org/errata/#current_errata>), | |
475 | dealing with glyph shaping in Arabic. | |
476 | ||
c93d2ba1 TC |
477 | =item * |
478 | ||
479 | op_free() no longer crashes due to a stack overflow when freeing a | |
480 | deeply recursive op tree. [perl #108276] | |
481 | ||
53795ef8 FC |
482 | =item * |
483 | ||
9d22ccf6 TC |
484 | scalarvoid() would crash due to a stack overflow when processing a |
485 | deeply recursive op tree. [perl #108276] | |
486 | ||
487 | =item * | |
488 | ||
53795ef8 FC |
489 | In Perl 5.20.0, C<$^N> accidentally had the internal UTF8 flag turned off |
490 | if accessed from a code block within a regular expression, effectively | |
491 | UTF8-encoding the value. This has been fixed. [perl #123135] | |
492 | ||
b7cd8332 FC |
493 | =item * |
494 | ||
495 | A failed C<semctl> call no longer overwrites existing items on the stack, | |
496 | causing C<(semctl(-1,0,0,0))[0]> to give an "uninitialized" warning. | |
497 | ||
480961b6 FC |
498 | =item * |
499 | ||
500 | C<else{foo()}> with no space before C<foo> is now better at assigning the | |
501 | right line number to that statement. [perl #122695] | |
502 | ||
94c9bf90 FC |
503 | =item * |
504 | ||
505 | Sometimes the assignment in C<@array = split> gets optimised and C<split> | |
506 | itself writes directly to the array. This caused a bug, preventing this | |
507 | assignment from being used in lvalue context. So | |
508 | C<(@a=split//,"foo")=bar()> was an error. (This bug probably goes back to | |
509 | Perl 3, when the optimisation was added.) This optimisation, and the bug, | |
510 | started to happen in more cases in 5.21.5. It has now been fixed. | |
511 | [perl #123057] | |
512 | ||
8af808bf FC |
513 | =item * |
514 | ||
515 | When argument lists that fail the checks installed by subroutine | |
516 | signatures, the resulting error messages now give the file and line number | |
517 | of the caller, not of the called subroutine. [perl #121374] | |
518 | ||
fdcaecb7 FC |
519 | =item * |
520 | ||
521 | Flip-flop operators (C<..> and C<...> in scalar context) used to maintain | |
522 | a separate state for each recursion level (the number of times the | |
523 | enclosing sub was called recursively), contrary to the documentation. Now | |
524 | each closure has one internal state for each flip-flop. [perl #122829] | |
525 | ||
2af7c6b6 FC |
526 | =item * |
527 | ||
528 | C<use>, C<no>, statement labels, special blocks (C<BEGIN>) and pod are now | |
529 | permitted as the first thing in a C<map> or C<grep> block, the block after | |
530 | C<print> or C<say> (or other functions) returning a handle, and within | |
531 | C<${...}>, C<@{...}>, etc. [perl #122782] | |
532 | ||
c0b32823 FC |
533 | =item * |
534 | ||
535 | The repetition operator C<x> now propagates lvalue context to its left-hand | |
536 | argument when used in contexts like C<foreach>. That allows | |
537 | C<for(($#that_array)x2) { ... }> to work as expected if the loop modifies | |
538 | $_. | |
539 | ||
b1a4e8b3 FC |
540 | =item * |
541 | ||
542 | C<(...) x ...> in scalar context used to corrupt the stack if one operand | |
543 | were an object with "x" overloading, causing erratic behaviour. | |
544 | [perl #121827] | |
545 | ||
86372193 | 546 | =back |
bb8c7e27 | 547 | |
86372193 | 548 | =head1 Known Problems |
bb8c7e27 | 549 | |
86372193 A |
550 | XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any |
551 | tests that had to be C<TODO>ed for the release would be noted here. Unfixed | |
552 | platform specific bugs also go here. | |
bb8c7e27 | 553 | |
86372193 | 554 | [ List each fix as a =item entry ] |
bb8c7e27 | 555 | |
86372193 | 556 | =over 4 |
bb8c7e27 | 557 | |
74f9f9ed A |
558 | =item * |
559 | ||
eacbb379 DD |
560 | Starting in 5.21.6, accessing L<perlapi/CvPADLIST> in an XSUB is forbidden. |
561 | CvPADLIST has be reused for a different internal purpose for XSUBs. Guard all | |
562 | CvPADLIST expressions with C<CvISXSUB()> if your code doesn't already block | |
563 | XSUB CV*s from going through optree CV* expecting code. | |
28a42920 | 564 | |
86372193 | 565 | =back |
28a42920 | 566 | |
86372193 | 567 | =head1 Errata From Previous Releases |
28a42920 | 568 | |
86372193 | 569 | =over 4 |
28a42920 A |
570 | |
571 | =item * | |
572 | ||
857f4fb1 FC |
573 | Due to a mistake in the string-copying logic, copying the value of a state |
574 | variable could instead steal the value and undefine the variable. This | |
575 | bug, introduced in 5.20, would happen mostly for long strings (1250 chars | |
576 | or more), but could happen for any strings under builds with copy-on-write | |
577 | disabled. [perl #123029] | |
578 | ||
579 | This bug was actually fixed in 5.21.5, but it was not until after that | |
580 | release that this bug, and the fact that it had been fixed, were | |
581 | discovered. | |
28a42920 | 582 | |
8c8d6154 | 583 | =back |
3a085d00 | 584 | |
86372193 | 585 | =head1 Obituary |
01d42a22 | 586 | |
86372193 A |
587 | XXX If any significant core contributor has died, we've added a short obituary |
588 | here. | |
01d42a22 | 589 | |
86372193 | 590 | =head1 Acknowledgements |
01d42a22 | 591 | |
86372193 | 592 | XXX Generate this with: |
01d42a22 | 593 | |
86372193 | 594 | perl Porting/acknowledgements.pl v5.21.5..HEAD |
f5b73711 | 595 | |
44691e6f AB |
596 | =head1 Reporting Bugs |
597 | ||
e08634c5 SH |
598 | If you find what you think is a bug, you might check the articles recently |
599 | posted to the comp.lang.perl.misc newsgroup and the perl bug database at | |
238894db | 600 | https://rt.perl.org/ . There may also be information at |
7ef8b31d | 601 | http://www.perl.org/ , the Perl Home Page. |
44691e6f | 602 | |
e08634c5 SH |
603 | If you believe you have an unreported bug, please run the L<perlbug> program |
604 | included with your release. Be sure to trim your bug down to a tiny but | |
605 | sufficient test case. Your bug report, along with the output of C<perl -V>, | |
606 | will be sent off to perlbug@perl.org to be analysed by the Perl porting team. | |
44691e6f AB |
607 | |
608 | If the bug you are reporting has security implications, which make it | |
e08634c5 SH |
609 | inappropriate to send to a publicly archived mailing list, then please send it |
610 | to perl5-security-report@perl.org. This points to a closed subscription | |
611 | unarchived mailing list, which includes all the core committers, who will be | |
612 | able to help assess the impact of issues, figure out a resolution, and help | |
f9001595 | 613 | co-ordinate the release of patches to mitigate or fix the problem across all |
e08634c5 SH |
614 | platforms on which Perl is supported. Please only use this address for |
615 | security issues in the Perl core, not for modules independently distributed on | |
616 | CPAN. | |
44691e6f AB |
617 | |
618 | =head1 SEE ALSO | |
619 | ||
e08634c5 SH |
620 | The F<Changes> file for an explanation of how to view exhaustive details on |
621 | what changed. | |
44691e6f AB |
622 | |
623 | The F<INSTALL> file for how to build Perl. | |
624 | ||
625 | The F<README> file for general stuff. | |
626 | ||
627 | The F<Artistic> and F<Copying> files for copyright information. | |
628 | ||
629 | =cut |