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1 | =encoding utf8 |
2 | ||
3 | =head1 NAME | |
4 | ||
583aa5c2 RS |
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 v5.19.1 | |
e128ab2c | 9 | |
4eabcf70 | 10 | =head1 DESCRIPTION |
6db9054f | 11 | |
583aa5c2 | 12 | This document describes differences between the 5.19.0 release and the 5.19.1 |
e08634c5 | 13 | release. |
6db9054f | 14 | |
e9912eaa | 15 | =head1 Notice |
5ed58cbd | 16 | |
583aa5c2 RS |
17 | XXX Any important notices here |
18 | ||
19 | =head1 Core Enhancements | |
20 | ||
21 | XXX New core language features go here. Summarize user-visible core language | |
22 | enhancements. Particularly prominent performance optimisations could go | |
23 | here, but most should go in the L</Performance Enhancements> section. | |
24 | ||
25 | [ List each enhancement as a =head2 entry ] | |
26 | ||
27 | =head1 Security | |
28 | ||
29 | XXX Any security-related notices go here. In particular, any security | |
30 | vulnerabilities closed should be noted here rather than in the | |
31 | L</Selected Bug Fixes> section. | |
32 | ||
33 | [ List each security issue as a =head2 entry ] | |
34 | ||
35 | =head1 Incompatible Changes | |
36 | ||
37 | XXX For a release on a stable branch, this section aspires to be: | |
38 | ||
39 | There are no changes intentionally incompatible with 5.XXX.XXX | |
40 | If any exist, they are bugs, and we request that you submit a | |
41 | report. See L</Reporting Bugs> below. | |
42 | ||
43 | [ List each incompatible change as a =head2 entry ] | |
44 | ||
45 | =head1 Deprecations | |
46 | ||
47 | XXX Any deprecated features, syntax, modules etc. should be listed here. | |
48 | ||
49 | =head2 Module removals | |
50 | ||
51 | XXX Remove this section if inapplicable. | |
52 | ||
53 | The following modules will be removed from the core distribution in a future | |
54 | release, and will at that time need to be installed from CPAN. Distributions | |
55 | on CPAN which require these modules will need to list them as prerequisites. | |
56 | ||
57 | The core versions of these modules will now issue C<"deprecated">-category | |
58 | warnings to alert you to this fact. To silence these deprecation warnings, | |
59 | install the modules in question from CPAN. | |
60 | ||
61 | Note that these are (with rare exceptions) fine modules that you are encouraged | |
62 | to continue to use. Their disinclusion from core primarily hinges on their | |
63 | necessity to bootstrapping a fully functional, CPAN-capable Perl installation, | |
64 | not usually on concerns over their design. | |
65 | ||
66 | XXX Note that deprecated modules should be listed here even if they are listed | |
67 | as an updated module in the L</Modules and Pragmata> section. | |
68 | ||
69 | =over | |
70 | ||
71 | =item * | |
72 | ||
73 | ... | |
74 | ||
75 | =back | |
76 | ||
77 | [ List each other deprecation as a =head2 entry ] | |
78 | ||
79 | =head1 Performance Enhancements | |
80 | ||
81 | XXX Changes which enhance performance without changing behaviour go here. | |
82 | There may well be none in a stable release. | |
83 | ||
84 | [ List each enhancement as a =item entry ] | |
85 | ||
86 | =over 4 | |
87 | ||
88 | =item * | |
89 | ||
13b0f67d DM |
90 | Perl has a new copy-on-write mechanism that avoids the need to copy the |
91 | internal string buffer when assigning from one scalar to another. This | |
92 | makes copying large strings appear much faster. Modifying one of the two | |
93 | (or more) strings after an assignment will force a copy internally. This | |
94 | makes it unnecessary to pass strings by reference for efficiency. | |
95 | ||
96 | This feature was already available in 5.18.0, but wasn't enabled by | |
97 | default. It is the default now, and so you no longer need build perl with | |
98 | the F<Configure> argument: | |
99 | ||
100 | -Accflags=PERL_NEW_COPY_ON_WRITE | |
101 | ||
102 | It can be disabled (for now) in a perl build with: | |
103 | ||
104 | -Accflags=PERL_NO_COW | |
583aa5c2 RS |
105 | |
106 | =back | |
5ed58cbd | 107 | |
e9912eaa | 108 | =head1 Modules and Pragmata |
5ed58cbd | 109 | |
583aa5c2 RS |
110 | XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/> |
111 | go here. If Module::CoreList is updated, generate an initial draft of the | |
112 | following sections using F<Porting/corelist-perldelta.pl>, which prints stub | |
113 | entries to STDOUT. Results can be pasted in place of the '=head2' entries | |
114 | below. A paragraph summary for important changes should then be added by hand. | |
115 | In an ideal world, dual-life modules would have a F<Changes> file that could be | |
116 | cribbed. | |
117 | ||
118 | [ Within each section, list entries as a =item entry ] | |
119 | ||
120 | =head2 New Modules and Pragmata | |
121 | ||
122 | =over 4 | |
123 | ||
124 | =item * | |
125 | ||
126 | XXX | |
127 | ||
128 | =back | |
129 | ||
e9912eaa | 130 | =head2 Updated Modules and Pragmata |
5ed58cbd | 131 | |
e9912eaa | 132 | =over 4 |
5ed58cbd | 133 | |
e9912eaa | 134 | =item * |
5ed58cbd | 135 | |
dbd04185 NC |
136 | Test::Harness has been upgraded from version 3.26 to 3.28 |
137 | ||
138 | Memory usage is dramatically reduced. t/harness now uses about 10% of the | |
139 | memory used by 3.26 and earlier. | |
140 | ||
141 | C<PERL5LIB> is always propagated to a test's C<@INC>, even under C<-T>. | |
583aa5c2 | 142 | |
1fdd5e53 KW |
143 | =item * |
144 | ||
145 | Unicode::UCD has been upgraded from version 0.51 to 0.52. | |
146 | ||
147 | A function, L<Unicode::UCD/search_invlist()> is now available to do | |
148 | search an inversion list or map for a code point. | |
149 | ||
583aa5c2 RS |
150 | =back |
151 | ||
152 | =head2 Removed Modules and Pragmata | |
153 | ||
154 | =over 4 | |
5ed58cbd | 155 | |
e9912eaa | 156 | =item * |
5ed58cbd | 157 | |
583aa5c2 RS |
158 | XXX |
159 | ||
160 | =back | |
161 | ||
162 | =head1 Documentation | |
163 | ||
164 | XXX Changes to files in F<pod/> go here. Consider grouping entries by | |
165 | file and be sure to link to the appropriate page, e.g. L<perlfunc>. | |
166 | ||
167 | =head2 New Documentation | |
168 | ||
169 | XXX Changes which create B<new> files in F<pod/> go here. | |
170 | ||
171 | =head3 L<XXX> | |
172 | ||
173 | XXX Description of the purpose of the new file here | |
174 | ||
175 | =head2 Changes to Existing Documentation | |
176 | ||
177 | XXX Changes which significantly change existing files in F<pod/> go here. | |
178 | However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics> | |
179 | section. | |
180 | ||
181 | =head3 L<XXX> | |
182 | ||
183 | =over 4 | |
1993add8 | 184 | |
e9912eaa | 185 | =item * |
ec985017 | 186 | |
583aa5c2 RS |
187 | XXX Description of the change here |
188 | ||
189 | =back | |
190 | ||
191 | =head1 Diagnostics | |
192 | ||
193 | The following additions or changes have been made to diagnostic output, | |
194 | including warnings and fatal error messages. For the complete list of | |
195 | diagnostic messages, see L<perldiag>. | |
196 | ||
197 | XXX New or changed warnings emitted by the core's C<C> code go here. Also | |
198 | include any changes in L<perldiag> that reconcile it to the C<C> code. | |
199 | ||
200 | =head2 New Diagnostics | |
201 | ||
202 | XXX Newly added diagnostic messages go under here, separated into New Errors | |
203 | and New Warnings | |
204 | ||
205 | =head3 New Errors | |
206 | ||
207 | =over 4 | |
71e6aba6 RS |
208 | |
209 | =item * | |
210 | ||
583aa5c2 RS |
211 | XXX L<message|perldiag/"message"> |
212 | ||
213 | =back | |
214 | ||
215 | =head3 New Warnings | |
216 | ||
217 | =over 4 | |
71e6aba6 | 218 | |
d5f315e8 KW |
219 | =item * |
220 | ||
583aa5c2 | 221 | XXX L<message|perldiag/"message"> |
d5f315e8 | 222 | |
337fb649 | 223 | =back |
2426c394 | 224 | |
583aa5c2 | 225 | =head2 Changes to Existing Diagnostics |
e9912eaa | 226 | |
583aa5c2 | 227 | XXX Changes (i.e. rewording) of diagnostic messages go here |
357b01df | 228 | |
583aa5c2 | 229 | =over 4 |
357b01df | 230 | |
583aa5c2 | 231 | =item * |
357b01df | 232 | |
583aa5c2 | 233 | XXX Describe change here |
357b01df | 234 | |
583aa5c2 | 235 | =back |
357b01df | 236 | |
583aa5c2 | 237 | =head1 Utility Changes |
357b01df | 238 | |
583aa5c2 RS |
239 | XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go here. |
240 | Most of these are built within the directories F<utils> and F<x2p>. | |
357b01df | 241 | |
583aa5c2 RS |
242 | [ List utility changes as a =head3 entry for each utility and =item |
243 | entries for each change | |
244 | Use L<XXX> with program names to get proper documentation linking. ] | |
357b01df | 245 | |
583aa5c2 | 246 | =head3 L<XXX> |
357b01df | 247 | |
583aa5c2 | 248 | =over 4 |
357b01df | 249 | |
583aa5c2 | 250 | =item * |
357b01df | 251 | |
583aa5c2 | 252 | XXX |
357b01df | 253 | |
583aa5c2 RS |
254 | =back |
255 | ||
256 | =head1 Configuration and Compilation | |
257 | ||
258 | XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools | |
259 | go here. Any other changes to the Perl build process should be listed here. | |
260 | However, any platform-specific changes should be listed in the | |
261 | L</Platform Support> section, instead. | |
262 | ||
263 | [ List changes as a =item entry ]. | |
264 | ||
265 | =over 4 | |
266 | ||
267 | =item * | |
268 | ||
269 | XXX | |
357b01df | 270 | |
e9912eaa | 271 | =back |
357b01df | 272 | |
583aa5c2 RS |
273 | =head1 Testing |
274 | ||
275 | XXX Any significant changes to the testing of a freshly built perl should be | |
276 | listed here. Changes which create B<new> files in F<t/> go here as do any | |
277 | large changes to the testing harness (e.g. when parallel testing was added). | |
278 | Changes to existing files in F<t/> aren't worth summarizing, although the bugs | |
279 | that they represent may be covered elsewhere. | |
280 | ||
281 | [ List each test improvement as a =item entry ] | |
282 | ||
283 | =over 4 | |
284 | ||
285 | =item * | |
286 | ||
287 | XXX | |
288 | ||
289 | =back | |
290 | ||
291 | =head1 Platform Support | |
292 | ||
293 | XXX Any changes to platform support should be listed in the sections below. | |
294 | ||
295 | [ Within the sections, list each platform as a =item entry with specific | |
296 | changes as paragraphs below it. ] | |
297 | ||
298 | =head2 New Platforms | |
299 | ||
300 | XXX List any platforms that this version of perl compiles on, that previous | |
301 | versions did not. These will either be enabled by new files in the F<hints/> | |
302 | directories, or new subdirectories and F<README> files at the top level of the | |
303 | source tree. | |
304 | ||
305 | =over 4 | |
306 | ||
307 | =item XXX-some-platform | |
308 | ||
309 | XXX | |
310 | ||
311 | =back | |
312 | ||
313 | =head2 Discontinued Platforms | |
314 | ||
315 | XXX List any platforms that this version of perl no longer compiles on. | |
316 | ||
317 | =over 4 | |
318 | ||
319 | =item XXX-some-platform | |
357b01df | 320 | |
583aa5c2 | 321 | XXX |
5ed58cbd | 322 | |
583aa5c2 RS |
323 | =back |
324 | ||
325 | =head2 Platform-Specific Notes | |
326 | ||
327 | XXX List any changes for specific platforms. This could include configuration | |
328 | and compilation changes or changes in portability/compatibility. However, | |
329 | changes within modules for platforms should generally be listed in the | |
330 | L</Modules and Pragmata> section. | |
331 | ||
332 | =over 4 | |
333 | ||
7df6ffa3 | 334 | =item Mixed-endian platforms |
583aa5c2 | 335 | |
7df6ffa3 NC |
336 | The code supporting C<pack> and C<unpack> operations on mixed endian |
337 | platforms has been removed. We believe that Perl has long been unable to | |
338 | build on mixed endian architectures (such as PDP-11s), so we don't think | |
339 | that this change will affect any platforms which are able to build v5.18.0. | |
583aa5c2 RS |
340 | |
341 | =back | |
342 | ||
343 | =head1 Internal Changes | |
344 | ||
345 | XXX Changes which affect the interface available to C<XS> code go here. Other | |
346 | significant internal changes for future core maintainers should be noted as | |
347 | well. | |
348 | ||
349 | [ List each change as a =item entry ] | |
350 | ||
351 | =over 4 | |
352 | ||
353 | =item * | |
354 | ||
13b0f67d DM |
355 | Perl's new copy-on-write mechanism (which is now enabled by default), |
356 | allows any C<SvPOK> scalar to be automatically upgraded to a copy-on-write | |
357 | scalar when copied. A reference count on the string buffer is stored in | |
358 | the string buffer itself. | |
359 | ||
360 | For example: | |
361 | ||
362 | $ perl -MDevel::Peek -e'$a="abc"; $b = $a; Dump $a; Dump $b' | |
363 | SV = PV(0x260cd80) at 0x2620ad8 | |
364 | REFCNT = 1 | |
365 | FLAGS = (POK,IsCOW,pPOK) | |
366 | PV = 0x2619bc0 "abc"\0 | |
367 | CUR = 3 | |
368 | LEN = 16 | |
369 | COW_REFCNT = 1 | |
370 | SV = PV(0x260ce30) at 0x2620b20 | |
371 | REFCNT = 1 | |
372 | FLAGS = (POK,IsCOW,pPOK) | |
373 | PV = 0x2619bc0 "abc"\0 | |
374 | CUR = 3 | |
375 | LEN = 16 | |
376 | COW_REFCNT = 1 | |
377 | ||
378 | Note that both scalars share the same PV buffer and have a COW_REFCNT | |
379 | greater than zero. | |
380 | ||
381 | This means that XS code which wishes to modify the C<SvPVX()> buffer of an | |
382 | SV should call C<SvPV_force()> or similar first, to ensure a valid (and | |
383 | unshared) buffer, and to call C<SvSETMAGIC()> afterwards. This in fact has | |
384 | always been the case (for example hash keys were already copy-on-write); | |
385 | this change just spreads the COW behaviour to a wider variety of SVs. | |
386 | ||
387 | One important difference is that before 5.18.0, shared hash-key scalars | |
388 | used to have the C<SvREADONLY> flag set; this is no longer the case. | |
389 | ||
390 | This new behaviour can still be disabled by running F<Configure> with | |
391 | B<-Accflags=-DPERL_NO_COW>. This option will probably be removed in Perl | |
392 | 5.22. | |
393 | ||
394 | =item * | |
395 | ||
396 | C<PL_sawampersand> is now a constant. The switch this variable provided | |
397 | (to enable/disable the pre-match copy depending on whether C<$&> had been | |
398 | seen) has been removed and replaced with copy-on-write, eliminating a few | |
399 | bugs. | |
400 | ||
401 | The previous behaviour can still be enabled by running F<Configure> with | |
402 | B<-Accflags=-DPERL_SAWAMPERSAND>. | |
403 | ||
404 | =item * | |
405 | ||
7df6ffa3 NC |
406 | The functions C<my_swap>, C<my_htonl> and C<my_ntohl> have been removed. |
407 | It is unclear why these functions were ever marked as I<A>, part of the | |
408 | API. XS code can't call them directly, as it can't rely on them being | |
409 | compiled. Unsurprisingly, no code on CPAN references them. | |
583aa5c2 RS |
410 | |
411 | =back | |
412 | ||
413 | =head1 Selected Bug Fixes | |
414 | ||
415 | XXX Important bug fixes in the core language are summarized here. Bug fixes in | |
416 | files in F<ext/> and F<lib/> are best summarized in L</Modules and Pragmata>. | |
5ed58cbd | 417 | |
583aa5c2 | 418 | [ List each fix as a =item entry ] |
32b79602 | 419 | |
583aa5c2 RS |
420 | =over 4 |
421 | ||
422 | =item * | |
423 | ||
c2a50ddb NC |
424 | The OP allocation code now returns correctly aligned memory in all cases |
425 | for C<struct pmop>. Previously it could return memory only aligned to a | |
426 | 4-byte boundary, which is not correct for an ithreads build with 64 bit IVs | |
427 | on some 32 bit platforms. Notably, this caused the build to fail completely | |
428 | on sparc GNU/Linux. [RT #118055] | |
583aa5c2 | 429 | |
b019bbd2 NC |
430 | =item * |
431 | ||
432 | The debugger's C<man> command been fixed. It was broken in the v5.18.0 | |
433 | release. The C<man> command is aliased to the names C<doc> and C<perldoc> - | |
434 | all now work again. | |
435 | ||
583aa5c2 RS |
436 | =back |
437 | ||
438 | =head1 Known Problems | |
439 | ||
440 | XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any | |
441 | tests that had to be C<TODO>ed for the release would be noted here. Unfixed | |
442 | platform specific bugs also go here. | |
443 | ||
444 | [ List each fix as a =item entry ] | |
445 | ||
446 | =over 4 | |
447 | ||
448 | =item * | |
449 | ||
450 | XXX | |
451 | ||
452 | =back | |
453 | ||
454 | =head1 Obituary | |
455 | ||
456 | XXX If any significant core contributor has died, we've added a short obituary | |
457 | here. | |
458 | ||
459 | =head1 Acknowledgements | |
a75569c0 | 460 | |
583aa5c2 | 461 | XXX Generate this with: |
e9912eaa | 462 | |
583aa5c2 | 463 | perl Porting/acknowledgements.pl v5.19.1..HEAD |
f5b73711 | 464 | |
44691e6f AB |
465 | =head1 Reporting Bugs |
466 | ||
e08634c5 SH |
467 | If you find what you think is a bug, you might check the articles recently |
468 | posted to the comp.lang.perl.misc newsgroup and the perl bug database at | |
469 | http://rt.perl.org/perlbug/ . There may also be information at | |
470 | http://www.perl.org/ , the Perl Home Page. | |
44691e6f | 471 | |
e08634c5 SH |
472 | If you believe you have an unreported bug, please run the L<perlbug> program |
473 | included with your release. Be sure to trim your bug down to a tiny but | |
474 | sufficient test case. Your bug report, along with the output of C<perl -V>, | |
475 | will be sent off to perlbug@perl.org to be analysed by the Perl porting team. | |
44691e6f AB |
476 | |
477 | If the bug you are reporting has security implications, which make it | |
e08634c5 SH |
478 | inappropriate to send to a publicly archived mailing list, then please send it |
479 | to perl5-security-report@perl.org. This points to a closed subscription | |
480 | unarchived mailing list, which includes all the core committers, who will be | |
481 | able to help assess the impact of issues, figure out a resolution, and help | |
f9001595 | 482 | co-ordinate the release of patches to mitigate or fix the problem across all |
e08634c5 SH |
483 | platforms on which Perl is supported. Please only use this address for |
484 | security issues in the Perl core, not for modules independently distributed on | |
485 | CPAN. | |
44691e6f AB |
486 | |
487 | =head1 SEE ALSO | |
488 | ||
e08634c5 SH |
489 | The F<Changes> file for an explanation of how to view exhaustive details on |
490 | what changed. | |
44691e6f AB |
491 | |
492 | The F<INSTALL> file for how to build Perl. | |
493 | ||
494 | The F<README> file for general stuff. | |
495 | ||
496 | The F<Artistic> and F<Copying> files for copyright information. | |
497 | ||
498 | =cut |