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04c692a8 | 1 | =encoding utf8 |
35c336e6 | 2 | |
04c692a8 DR |
3 | =for comment |
4 | Consistent formatting of this file is achieved with: | |
5 | perl ./Porting/podtidy pod/perlhack.pod | |
35c336e6 | 6 | |
04c692a8 | 7 | =head1 NAME |
35c336e6 | 8 | |
04c692a8 | 9 | perlhack - How to hack on Perl |
35c336e6 | 10 | |
04c692a8 | 11 | =head1 DESCRIPTION |
35c336e6 | 12 | |
531e2078 | 13 | This document explains how Perl development works. It includes details |
04c692a8 DR |
14 | about the Perl 5 Porters email list, the Perl repository, the Perlbug |
15 | bug tracker, patch guidelines, and commentary on Perl development | |
16 | philosophy. | |
f7e1e956 | 17 | |
04c692a8 | 18 | =head1 SUPER QUICK PATCH GUIDE |
f7e1e956 | 19 | |
04c692a8 DR |
20 | If you just want to submit a single small patch like a pod fix, a test |
21 | for a bug, comment fixes, etc., it's easy! Here's how: | |
f7e1e956 | 22 | |
04c692a8 | 23 | =over 4 |
e018f8be | 24 | |
04c692a8 | 25 | =item * Check out the source repository |
e018f8be | 26 | |
531e2078 | 27 | The perl source is in a git repository. You can clone the repository |
04c692a8 | 28 | with the following command: |
e018f8be | 29 | |
04c692a8 | 30 | % git clone git://perl5.git.perl.org/perl.git perl |
e018f8be | 31 | |
69434957 S |
32 | =item * Ensure you're following the latest advice |
33 | ||
34 | In case the advice in this guide has been updated recently, read the | |
35 | latest version directly from the perl source: | |
36 | ||
37 | % perldoc pod/perlhack.pod | |
38 | ||
04c692a8 | 39 | =item * Make your change |
e018f8be | 40 | |
04c692a8 | 41 | Hack, hack, hack. |
7205a85d | 42 | |
04c692a8 | 43 | =item * Test your change |
e018f8be | 44 | |
04c692a8 | 45 | You can run all the tests with the following commands: |
b26492ee | 46 | |
04c692a8 DR |
47 | % ./Configure -des -Dusedevel |
48 | % make test | |
7205a85d | 49 | |
04c692a8 | 50 | Keep hacking until the tests pass. |
b26492ee | 51 | |
04c692a8 | 52 | =item * Commit your change |
e018f8be | 53 | |
b6538e4f | 54 | Committing your work will save the change I<on your local system>: |
7205a85d | 55 | |
04c692a8 | 56 | % git commit -a -m 'Commit message goes here' |
e018f8be | 57 | |
04c692a8 | 58 | Make sure the commit message describes your change in a single |
531e2078 | 59 | sentence. For example, "Fixed spelling errors in perlhack.pod". |
e018f8be | 60 | |
04c692a8 | 61 | =item * Send your change to perlbug |
7a834142 | 62 | |
04c692a8 DR |
63 | The next step is to submit your patch to the Perl core ticket system |
64 | via email. | |
7a834142 | 65 | |
84788b0a | 66 | If your changes are in a single git commit, run the following commands |
e7769b3e | 67 | to generate the patch file and attach it to your bug report: |
e018f8be | 68 | |
e7769b3e CB |
69 | % git format-patch -1 |
70 | % ./perl -Ilib utils/perlbug -p 0001-*.patch | |
e018f8be | 71 | |
04c692a8 | 72 | The perlbug program will ask you a few questions about your email |
531e2078 | 73 | address and the patch you're submitting. Once you've answered them it |
84b19098 | 74 | will submit your patch via email. |
e018f8be | 75 | |
e7769b3e CB |
76 | If your changes are in multiple commits, generate a patch file for each |
77 | one and provide them to perlbug's C<-p> option separated by commas: | |
2d1c9392 | 78 | |
e7769b3e CB |
79 | % git format-patch -3 |
80 | % ./perl -Ilib utils/perlbug -p 0001-fix1.patch,0002-fix2.patch,\ | |
81 | > 0003-fix3.patch | |
2d1c9392 | 82 | |
e7769b3e | 83 | When prompted, pick a subject that summarizes your changes. |
2d1c9392 | 84 | |
04c692a8 | 85 | =item * Thank you |
e018f8be | 86 | |
04c692a8 DR |
87 | The porters appreciate the time you spent helping to make Perl better. |
88 | Thank you! | |
e018f8be | 89 | |
e99cf3f0 S |
90 | =item * Next time |
91 | ||
92 | The next time you wish to make a patch, you need to start from the | |
30454452 | 93 | latest perl in a pristine state. Check you don't have any local changes |
e99cf3f0 S |
94 | or added files in your perl check-out which you wish to keep, then run |
95 | these commands: | |
96 | ||
97 | % git pull | |
98 | % git reset --hard origin/blead | |
99 | % git clean -dxf | |
100 | ||
cce04beb | 101 | =back |
e018f8be | 102 | |
04c692a8 | 103 | =head1 BUG REPORTING |
cc0710ff | 104 | |
9e6670f3 | 105 | If you want to report a bug in Perl, you must use the F<perlbug> |
531e2078 | 106 | command line tool. This tool will ensure that your bug report includes |
9e6670f3 | 107 | all the relevant system and configuration information. |
7205a85d | 108 | |
04c692a8 | 109 | To browse existing Perl bugs and patches, you can use the web interface |
a8d15a22 | 110 | at L<http://rt.perl.org/>. |
244d9cb7 | 111 | |
04c692a8 | 112 | Please check the archive of the perl5-porters list (see below) and/or |
531e2078 | 113 | the bug tracking system before submitting a bug report. Often, you'll |
04c692a8 | 114 | find that the bug has been reported already. |
244d9cb7 | 115 | |
04c692a8 | 116 | You can log in to the bug tracking system and comment on existing bug |
531e2078 FC |
117 | reports. If you have additional information regarding an existing bug, |
118 | please add it. This will help the porters fix the bug. | |
7205a85d | 119 | |
04c692a8 | 120 | =head1 PERL 5 PORTERS |
7205a85d | 121 | |
04c692a8 | 122 | The perl5-porters (p5p) mailing list is where the Perl standard |
531e2078 | 123 | distribution is maintained and developed. The people who maintain Perl |
9e6670f3 DR |
124 | are also referred to as the "Perl 5 Porters", "p5p" or just the |
125 | "porters". | |
a75f557c | 126 | |
04c692a8 | 127 | A searchable archive of the list is available at |
531e2078 | 128 | L<http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/>. There is |
04c692a8 DR |
129 | also another archive at |
130 | L<http://archive.develooper.com/perl5-porters@perl.org/>. | |
7205a85d | 131 | |
04c692a8 | 132 | =head2 perl-changes mailing list |
7205a85d | 133 | |
04c692a8 DR |
134 | The perl5-changes mailing list receives a copy of each patch that gets |
135 | submitted to the maintenance and development branches of the perl | |
531e2078 | 136 | repository. See L<http://lists.perl.org/list/perl5-changes.html> for |
04c692a8 | 137 | subscription and archive information. |
244d9cb7 | 138 | |
37bf3a91 DR |
139 | =head2 #p5p on IRC |
140 | ||
141 | Many porters are also active on the L<irc://irc.perl.org/#p5p> channel. | |
142 | Feel free to join the channel and ask questions about hacking on the | |
143 | Perl core. | |
144 | ||
04c692a8 | 145 | =head1 GETTING THE PERL SOURCE |
244d9cb7 | 146 | |
04c692a8 | 147 | All of Perl's source code is kept centrally in a Git repository at |
a44b8c28 S |
148 | I<perl5.git.perl.org>. The repository contains many Perl revisions |
149 | from Perl 1 onwards and all the revisions from Perforce, the previous | |
04c692a8 | 150 | version control system. |
244d9cb7 | 151 | |
04c692a8 DR |
152 | For much more detail on using git with the Perl repository, please see |
153 | L<perlgit>. | |
244d9cb7 | 154 | |
04c692a8 | 155 | =head2 Read access via Git |
244d9cb7 | 156 | |
531e2078 | 157 | You will need a copy of Git for your computer. You can fetch a copy of |
04c692a8 | 158 | the repository using the git protocol: |
244d9cb7 | 159 | |
04c692a8 | 160 | % git clone git://perl5.git.perl.org/perl.git perl |
244d9cb7 | 161 | |
04c692a8 DR |
162 | This clones the repository and makes a local copy in the F<perl> |
163 | directory. | |
7205a85d | 164 | |
04c692a8 DR |
165 | If you cannot use the git protocol for firewall reasons, you can also |
166 | clone via http, though this is much slower: | |
7205a85d | 167 | |
04c692a8 | 168 | % git clone http://perl5.git.perl.org/perl.git perl |
7205a85d | 169 | |
04c692a8 | 170 | =head2 Read access via the web |
7205a85d | 171 | |
531e2078 | 172 | You may access the repository over the web. This allows you to browse |
04c692a8 | 173 | the tree, see recent commits, subscribe to RSS feeds for the changes, |
531e2078 FC |
174 | search for particular commits and more. You may access it at |
175 | L<http://perl5.git.perl.org/perl.git>. A mirror of the repository is | |
b0959619 | 176 | found at L<https://github.com/Perl/perl5>. |
7205a85d | 177 | |
04c692a8 | 178 | =head2 Read access via rsync |
7205a85d | 179 | |
04c692a8 DR |
180 | You can also choose to use rsync to get a copy of the current source |
181 | tree for the bleadperl branch and all maintenance branches: | |
7205a85d | 182 | |
7eac65da S |
183 | % rsync -avz rsync://perl5.git.perl.org/perl-current . |
184 | % rsync -avz rsync://perl5.git.perl.org/perl-5.12.x . | |
185 | % rsync -avz rsync://perl5.git.perl.org/perl-5.10.x . | |
186 | % rsync -avz rsync://perl5.git.perl.org/perl-5.8.x . | |
187 | % rsync -avz rsync://perl5.git.perl.org/perl-5.6.x . | |
188 | % rsync -avz rsync://perl5.git.perl.org/perl-5.005xx . | |
7205a85d | 189 | |
a8d15a22 | 190 | (Add the C<--delete> option to remove leftover files.) |
7205a85d | 191 | |
04c692a8 | 192 | To get a full list of the available sync points: |
7205a85d | 193 | |
7eac65da | 194 | % rsync perl5.git.perl.org:: |
7205a85d | 195 | |
04c692a8 | 196 | =head2 Write access via git |
7205a85d | 197 | |
04c692a8 DR |
198 | If you have a commit bit, please see L<perlgit> for more details on |
199 | using git. | |
7205a85d | 200 | |
04c692a8 | 201 | =head1 PATCHING PERL |
7205a85d | 202 | |
04c692a8 | 203 | If you're planning to do more extensive work than a single small fix, |
531e2078 | 204 | we encourage you to read the documentation below. This will help you |
04c692a8 DR |
205 | focus your work and make your patches easier to incorporate into the |
206 | Perl source. | |
244d9cb7 | 207 | |
04c692a8 | 208 | =head2 Submitting patches |
244d9cb7 | 209 | |
531e2078 FC |
210 | If you have a small patch to submit, please submit it via perlbug. You |
211 | can also send email directly to perlbug@perl.org. Please note that | |
04c692a8 DR |
212 | messages sent to perlbug may be held in a moderation queue, so you |
213 | won't receive a response immediately. | |
244d9cb7 | 214 | |
04c692a8 | 215 | You'll know your submission has been processed when you receive an |
531e2078 FC |
216 | email from our ticket tracking system. This email will give you a |
217 | ticket number. Once your patch has made it to the ticket tracking | |
04c692a8 | 218 | system, it will also be sent to the perl5-porters@perl.org list. |
244d9cb7 | 219 | |
531e2078 | 220 | Patches are reviewed and discussed on the p5p list. Simple, |
04c692a8 DR |
221 | uncontroversial patches will usually be applied without any discussion. |
222 | When the patch is applied, the ticket will be updated and you will | |
531e2078 | 223 | receive email. In addition, an email will be sent to the p5p list. |
244d9cb7 | 224 | |
531e2078 | 225 | In other cases, the patch will need more work or discussion. That will |
04c692a8 | 226 | happen on the p5p list. |
244d9cb7 | 227 | |
04c692a8 | 228 | You are encouraged to participate in the discussion and advocate for |
531e2078 | 229 | your patch. Sometimes your patch may get lost in the shuffle. It's |
04c692a8 | 230 | appropriate to send a reminder email to p5p if no action has been taken |
531e2078 | 231 | in a month. Please remember that the Perl 5 developers are all |
04c692a8 | 232 | volunteers, and be polite. |
244d9cb7 | 233 | |
04c692a8 | 234 | Changes are always applied directly to the main development branch, |
a44b8c28 | 235 | called "blead". Some patches may be backported to a maintenance |
30454452 | 236 | branch. If you think your patch is appropriate for the maintenance |
839a0e5a | 237 | branch (see L<perlpolicy/MAINTENANCE BRANCHES>), please explain why |
d0bba22e | 238 | when you submit it. |
244d9cb7 | 239 | |
04c692a8 | 240 | =head2 Getting your patch accepted |
244d9cb7 | 241 | |
84c2f6fd DR |
242 | If you are submitting a code patch there are several things that you |
243 | can do to help the Perl 5 Porters accept your patch. | |
244d9cb7 | 244 | |
a126fb62 DR |
245 | =head3 Patch style |
246 | ||
247 | If you used git to check out the Perl source, then using C<git | |
531e2078 | 248 | format-patch> will produce a patch in a style suitable for Perl. The |
a126fb62 | 249 | C<format-patch> command produces one patch file for each commit you |
a44b8c28 S |
250 | made. If you prefer to send a single patch for all commits, you can |
251 | use C<git diff>. | |
a126fb62 | 252 | |
9d440a18 | 253 | % git checkout blead |
a126fb62 DR |
254 | % git pull |
255 | % git diff blead my-branch-name | |
256 | ||
257 | This produces a patch based on the difference between blead and your | |
531e2078 | 258 | current branch. It's important to make sure that blead is up to date |
a126fb62 DR |
259 | before producing the diff, that's why we call C<git pull> first. |
260 | ||
531e2078 | 261 | We strongly recommend that you use git if possible. It will make your |
a126fb62 DR |
262 | life easier, and ours as well. |
263 | ||
264 | However, if you're not using git, you can still produce a suitable | |
531e2078 FC |
265 | patch. You'll need a pristine copy of the Perl source to diff against. |
266 | The porters prefer unified diffs. Using GNU C<diff>, you can produce a | |
a126fb62 DR |
267 | diff like this: |
268 | ||
269 | % diff -Npurd perl.pristine perl.mine | |
270 | ||
271 | Make sure that you C<make realclean> in your copy of Perl to remove any | |
272 | build artifacts, or you may get a confusing result. | |
273 | ||
04c692a8 | 274 | =head3 Commit message |
244d9cb7 | 275 | |
04c692a8 | 276 | As you craft each patch you intend to submit to the Perl core, it's |
531e2078 | 277 | important to write a good commit message. This is especially important |
04c692a8 | 278 | if your submission will consist of a series of commits. |
244d9cb7 | 279 | |
04c692a8 | 280 | The first line of the commit message should be a short description |
531e2078 | 281 | without a period. It should be no longer than the subject line of an |
a8d15a22 | 282 | email, 50 characters being a good rule of thumb. |
f7e1e956 | 283 | |
a8d15a22 | 284 | A lot of Git tools (Gitweb, GitHub, git log --pretty=oneline, ...) will |
04c692a8 DR |
285 | only display the first line (cut off at 50 characters) when presenting |
286 | commit summaries. | |
7cd58830 | 287 | |
04c692a8 DR |
288 | The commit message should include a description of the problem that the |
289 | patch corrects or new functionality that the patch adds. | |
7cd58830 | 290 | |
04c692a8 DR |
291 | As a general rule of thumb, your commit message should help a |
292 | programmer who knows the Perl core quickly understand what you were | |
293 | trying to do, how you were trying to do it, and why the change matters | |
294 | to Perl. | |
7cd58830 | 295 | |
04c692a8 | 296 | =over 4 |
7cd58830 | 297 | |
04c692a8 | 298 | =item * Why |
7cd58830 | 299 | |
04c692a8 | 300 | Your commit message should describe why the change you are making is |
531e2078 | 301 | important. When someone looks at your change in six months or six |
04c692a8 | 302 | years, your intent should be clear. |
7cd58830 | 303 | |
04c692a8 | 304 | If you're deprecating a feature with the intent of later simplifying |
531e2078 | 305 | another bit of code, say so. If you're fixing a performance problem or |
04c692a8 DR |
306 | adding a new feature to support some other bit of the core, mention |
307 | that. | |
7cd58830 | 308 | |
04c692a8 | 309 | =item * What |
7cd58830 | 310 | |
04c692a8 DR |
311 | Your commit message should describe what part of the Perl core you're |
312 | changing and what you expect your patch to do. | |
7cd58830 | 313 | |
04c692a8 | 314 | =item * How |
7cd58830 | 315 | |
04c692a8 DR |
316 | While it's not necessary for documentation changes, new tests or |
317 | trivial patches, it's often worth explaining how your change works. | |
318 | Even if it's clear to you today, it may not be clear to a porter next | |
319 | month or next year. | |
d7889f52 | 320 | |
04c692a8 | 321 | =back |
d7889f52 | 322 | |
04c692a8 | 323 | A commit message isn't intended to take the place of comments in your |
531e2078 | 324 | code. Commit messages should describe the change you made, while code |
04c692a8 | 325 | comments should describe the current state of the code. |
d7889f52 | 326 | |
04c692a8 | 327 | If you've just implemented a new feature, complete with doc, tests and |
531e2078 | 328 | well-commented code, a brief commit message will often suffice. If, |
04c692a8 DR |
329 | however, you've just changed a single character deep in the parser or |
330 | lexer, you might need to write a small novel to ensure that future | |
331 | readers understand what you did and why you did it. | |
d7889f52 | 332 | |
04c692a8 | 333 | =head3 Comments, Comments, Comments |
d7889f52 | 334 | |
a44b8c28 S |
335 | Be sure to adequately comment your code. While commenting every line |
336 | is unnecessary, anything that takes advantage of side effects of | |
04c692a8 DR |
337 | operators, that creates changes that will be felt outside of the |
338 | function being patched, or that others may find confusing should be | |
a44b8c28 S |
339 | documented. If you are going to err, it is better to err on the side |
340 | of adding too many comments than too few. | |
d7889f52 | 341 | |
04c692a8 DR |
342 | The best comments explain I<why> the code does what it does, not I<what |
343 | it does>. | |
d7889f52 | 344 | |
04c692a8 | 345 | =head3 Style |
d7889f52 | 346 | |
04c692a8 DR |
347 | In general, please follow the particular style of the code you are |
348 | patching. | |
d7889f52 | 349 | |
04c692a8 DR |
350 | In particular, follow these general guidelines for patching Perl |
351 | sources: | |
cce04beb | 352 | |
04c692a8 | 353 | =over 4 |
d7889f52 JH |
354 | |
355 | =item * | |
356 | ||
04c692a8 | 357 | 8-wide tabs (no exceptions!) |
d7889f52 JH |
358 | |
359 | =item * | |
360 | ||
04c692a8 | 361 | 4-wide indents for code, 2-wide indents for nested CPP #defines |
ee9468a2 | 362 | |
cce04beb | 363 | =item * |
ee9468a2 | 364 | |
04c692a8 | 365 | Try hard not to exceed 79-columns |
bc028b6b | 366 | |
ee9468a2 RGS |
367 | =item * |
368 | ||
04c692a8 | 369 | ANSI C prototypes |
d7889f52 JH |
370 | |
371 | =item * | |
372 | ||
04c692a8 | 373 | Uncuddled elses and "K&R" style for indenting control constructs |
0bec6c03 | 374 | |
04c692a8 | 375 | =item * |
d7889f52 | 376 | |
04c692a8 | 377 | No C++ style (//) comments |
d7889f52 JH |
378 | |
379 | =item * | |
380 | ||
04c692a8 | 381 | Mark places that need to be revisited with XXX (and revisit often!) |
27565cb6 JH |
382 | |
383 | =item * | |
384 | ||
04c692a8 DR |
385 | Opening brace lines up with "if" when conditional spans multiple lines; |
386 | should be at end-of-line otherwise | |
27565cb6 | 387 | |
04c692a8 | 388 | =item * |
27565cb6 | 389 | |
04c692a8 DR |
390 | In function definitions, name starts in column 0 (return value is on |
391 | previous line) | |
27565cb6 | 392 | |
04c692a8 | 393 | =item * |
27565cb6 | 394 | |
04c692a8 DR |
395 | Single space after keywords that are followed by parens, no space |
396 | between function name and following paren | |
606fd33d | 397 | |
27565cb6 JH |
398 | =item * |
399 | ||
04c692a8 DR |
400 | Avoid assignments in conditionals, but if they're unavoidable, use |
401 | extra paren, e.g. "if (a && (b = c)) ..." | |
27565cb6 JH |
402 | |
403 | =item * | |
404 | ||
04c692a8 | 405 | "return foo;" rather than "return(foo);" |
27565cb6 JH |
406 | |
407 | =item * | |
408 | ||
04c692a8 | 409 | "if (!foo) ..." rather than "if (foo == FALSE) ..." etc. |
606fd33d | 410 | |
a8bd0d47 KW |
411 | =item * |
412 | ||
413 | Do not declare variables using "register". It may be counterproductive | |
414 | with modern compilers, and is deprecated in C++, under which the Perl | |
415 | source is regularly compiled. | |
416 | ||
5b48d9bb KW |
417 | =item * |
418 | ||
419 | In-line functions that are in headers that are accessible to XS code | |
420 | need to be able to compile without warnings with commonly used extra | |
421 | compilation flags, such as gcc's C<-Wswitch-default> which warns | |
422 | whenever a switch statement does not have a "default" case. The use of | |
a44b8c28 S |
423 | these extra flags is to catch potential problems in legal C code, and |
424 | is often used by Perl aggregators, such as Linux distributors. | |
5b48d9bb | 425 | |
606fd33d | 426 | =back |
27565cb6 | 427 | |
04c692a8 | 428 | =head3 Test suite |
d7889f52 | 429 | |
a8d15a22 | 430 | If your patch changes code (rather than just changing documentation), |
04c692a8 | 431 | you should also include one or more test cases which illustrate the bug |
531e2078 | 432 | you're fixing or validate the new functionality you're adding. In |
04c692a8 DR |
433 | general, you should update an existing test file rather than create a |
434 | new one. | |
2bbc8d55 | 435 | |
04c692a8 DR |
436 | Your test suite additions should generally follow these guidelines |
437 | (courtesy of Gurusamy Sarathy <gsar@activestate.com>): | |
2bbc8d55 | 438 | |
04c692a8 | 439 | =over 4 |
0bec6c03 | 440 | |
04c692a8 | 441 | =item * |
0bec6c03 | 442 | |
531e2078 | 443 | Know what you're testing. Read the docs, and the source. |
ee9468a2 RGS |
444 | |
445 | =item * | |
446 | ||
04c692a8 | 447 | Tend to fail, not succeed. |
0bec6c03 | 448 | |
04c692a8 | 449 | =item * |
0bec6c03 | 450 | |
04c692a8 | 451 | Interpret results strictly. |
27565cb6 | 452 | |
04c692a8 | 453 | =item * |
27565cb6 | 454 | |
04c692a8 | 455 | Use unrelated features (this will flush out bizarre interactions). |
27565cb6 | 456 | |
04c692a8 | 457 | =item * |
27565cb6 | 458 | |
04c692a8 | 459 | Use non-standard idioms (otherwise you are not testing TIMTOWTDI). |
27565cb6 | 460 | |
04c692a8 | 461 | =item * |
d7889f52 | 462 | |
04c692a8 DR |
463 | Avoid using hardcoded test numbers whenever possible (the EXPECTED/GOT |
464 | found in t/op/tie.t is much more maintainable, and gives better failure | |
465 | reports). | |
d7889f52 | 466 | |
04c692a8 | 467 | =item * |
d7889f52 | 468 | |
04c692a8 | 469 | Give meaningful error messages when a test fails. |
d7889f52 | 470 | |
04c692a8 | 471 | =item * |
d7889f52 | 472 | |
531e2078 | 473 | Avoid using qx// and system() unless you are testing for them. If you |
04c692a8 | 474 | do use them, make sure that you cover _all_ perl platforms. |
d7889f52 | 475 | |
04c692a8 | 476 | =item * |
0bec6c03 | 477 | |
04c692a8 | 478 | Unlink any temporary files you create. |
63796a85 | 479 | |
04c692a8 | 480 | =item * |
0bec6c03 | 481 | |
04c692a8 | 482 | Promote unforeseen warnings to errors with $SIG{__WARN__}. |
0bec6c03 | 483 | |
04c692a8 | 484 | =item * |
0bec6c03 | 485 | |
04c692a8 DR |
486 | Be sure to use the libraries and modules shipped with the version being |
487 | tested, not those that were already installed. | |
d7889f52 | 488 | |
04c692a8 | 489 | =item * |
d7889f52 | 490 | |
04c692a8 | 491 | Add comments to the code explaining what you are testing for. |
d7889f52 | 492 | |
04c692a8 | 493 | =item * |
d7889f52 | 494 | |
531e2078 | 495 | Make updating the '1..42' string unnecessary. Or make sure that you |
04c692a8 | 496 | update it. |
d7889f52 | 497 | |
04c692a8 | 498 | =item * |
d7889f52 | 499 | |
04c692a8 | 500 | Test _all_ behaviors of a given operator, library, or function. |
d7889f52 | 501 | |
04c692a8 | 502 | Test all optional arguments. |
d7889f52 | 503 | |
04c692a8 | 504 | Test return values in various contexts (boolean, scalar, list, lvalue). |
d7889f52 | 505 | |
04c692a8 | 506 | Use both global and lexical variables. |
d7889f52 | 507 | |
04c692a8 | 508 | Don't forget the exceptional, pathological cases. |
0bec6c03 | 509 | |
cce04beb | 510 | =back |
0bec6c03 | 511 | |
04c692a8 | 512 | =head2 Patching a core module |
ee9468a2 | 513 | |
04c692a8 DR |
514 | This works just like patching anything else, with one extra |
515 | consideration. | |
63796a85 | 516 | |
a8d15a22 | 517 | Modules in the F<cpan/> directory of the source tree are maintained |
531e2078 | 518 | outside of the Perl core. When the author updates the module, the |
24b68a05 DG |
519 | updates are simply copied into the core. See that module's |
520 | documentation or its listing on L<http://search.cpan.org/> for more | |
521 | information on reporting bugs and submitting patches. | |
522 | ||
523 | In most cases, patches to modules in F<cpan/> should be sent upstream | |
9e6670f3 DR |
524 | and should not be applied to the Perl core individually. If a patch to |
525 | a file in F<cpan/> absolutely cannot wait for the fix to be made | |
7e5887a1 DG |
526 | upstream, released to CPAN and copied to blead, you must add (or |
527 | update) a C<CUSTOMIZED> entry in the F<"Porting/Maintainers.pl"> file | |
528 | to flag that a local modification has been made. See | |
529 | F<"Porting/Maintainers.pl"> for more details. | |
63796a85 | 530 | |
04c692a8 DR |
531 | In contrast, modules in the F<dist/> directory are maintained in the |
532 | core. | |
63796a85 | 533 | |
04c692a8 | 534 | =head2 Updating perldelta |
63796a85 | 535 | |
04c692a8 DR |
536 | For changes significant enough to warrant a F<pod/perldelta.pod> entry, |
537 | the porters will greatly appreciate it if you submit a delta entry | |
a44b8c28 S |
538 | along with your actual change. Significant changes include, but are |
539 | not limited to: | |
63796a85 | 540 | |
04c692a8 | 541 | =over 4 |
63796a85 | 542 | |
04c692a8 | 543 | =item * |
63796a85 | 544 | |
04c692a8 | 545 | Adding, deprecating, or removing core features |
ee9468a2 | 546 | |
04c692a8 | 547 | =item * |
ee9468a2 | 548 | |
04c692a8 | 549 | Adding, deprecating, removing, or upgrading core or dual-life modules |
ee9468a2 | 550 | |
04c692a8 | 551 | =item * |
ee9468a2 | 552 | |
04c692a8 | 553 | Adding new core tests |
ee9468a2 | 554 | |
04c692a8 | 555 | =item * |
ee9468a2 | 556 | |
04c692a8 | 557 | Fixing security issues and user-visible bugs in the core |
cce04beb | 558 | |
04c692a8 | 559 | =item * |
ad7244db | 560 | |
04c692a8 | 561 | Changes that might break existing code, either on the perl or C level |
ad7244db JH |
562 | |
563 | =item * | |
564 | ||
04c692a8 | 565 | Significant performance improvements |
ad7244db JH |
566 | |
567 | =item * | |
568 | ||
04c692a8 DR |
569 | Adding, removing, or significantly changing documentation in the |
570 | F<pod/> directory | |
ad7244db | 571 | |
cce04beb | 572 | =item * |
ad7244db | 573 | |
04c692a8 | 574 | Important platform-specific changes |
d7889f52 | 575 | |
cce04beb DG |
576 | =back |
577 | ||
04c692a8 | 578 | Please make sure you add the perldelta entry to the right section |
531e2078 | 579 | within F<pod/perldelta.pod>. More information on how to write good |
04c692a8 DR |
580 | perldelta entries is available in the C<Style> section of |
581 | F<Porting/how_to_write_a_perldelta.pod>. | |
d7889f52 | 582 | |
04c692a8 | 583 | =head2 What makes for a good patch? |
d7889f52 | 584 | |
531e2078 | 585 | New features and extensions to the language can be contentious. There |
04c692a8 DR |
586 | is no specific set of criteria which determine what features get added, |
587 | but here are some questions to consider when developing a patch: | |
d7889f52 | 588 | |
04c692a8 | 589 | =head3 Does the concept match the general goals of Perl? |
d7889f52 | 590 | |
04c692a8 | 591 | Our goals include, but are not limited to: |
d7889f52 | 592 | |
04c692a8 | 593 | =over 4 |
d7889f52 | 594 | |
04c692a8 | 595 | =item 1. |
d7889f52 | 596 | |
04c692a8 | 597 | Keep it fast, simple, and useful. |
cce04beb | 598 | |
04c692a8 | 599 | =item 2. |
cce04beb | 600 | |
04c692a8 | 601 | Keep features/concepts as orthogonal as possible. |
902b9dbf | 602 | |
04c692a8 | 603 | =item 3. |
902b9dbf | 604 | |
04c692a8 | 605 | No arbitrary limits (platforms, data sizes, cultures). |
a958818a | 606 | |
04c692a8 | 607 | =item 4. |
ac036724 | 608 | |
04c692a8 | 609 | Keep it open and exciting to use/patch/advocate Perl everywhere. |
a958818a | 610 | |
04c692a8 | 611 | =item 5. |
a958818a | 612 | |
04c692a8 | 613 | Either assimilate new technologies, or build bridges to them. |
a958818a | 614 | |
04c692a8 | 615 | =back |
a958818a | 616 | |
04c692a8 | 617 | =head3 Where is the implementation? |
a958818a | 618 | |
531e2078 | 619 | All the talk in the world is useless without an implementation. In |
04c692a8 | 620 | almost every case, the person or people who argue for a new feature |
531e2078 | 621 | will be expected to be the ones who implement it. Porters capable of |
04c692a8 DR |
622 | coding new features have their own agendas, and are not available to |
623 | implement your (possibly good) idea. | |
a1b65709 | 624 | |
04c692a8 | 625 | =head3 Backwards compatibility |
37c0adeb | 626 | |
531e2078 | 627 | It's a cardinal sin to break existing Perl programs. New warnings can |
04c692a8 | 628 | be contentious--some say that a program that emits warnings is not |
531e2078 | 629 | broken, while others say it is. Adding keywords has the potential to |
04c692a8 DR |
630 | break programs, changing the meaning of existing token sequences or |
631 | functions might break programs. | |
f50e5b73 | 632 | |
04c692a8 DR |
633 | The Perl 5 core includes mechanisms to help porters make backwards |
634 | incompatible changes more compatible such as the L<feature> and | |
531e2078 | 635 | L<deprecate> modules. Please use them when appropriate. |
902b9dbf | 636 | |
04c692a8 | 637 | =head3 Could it be a module instead? |
902b9dbf | 638 | |
04c692a8 | 639 | Perl 5 has extension mechanisms, modules and XS, specifically to avoid |
531e2078 | 640 | the need to keep changing the Perl interpreter. You can write modules |
04c692a8 DR |
641 | that export functions, you can give those functions prototypes so they |
642 | can be called like built-in functions, you can even write XS code to | |
643 | mess with the runtime data structures of the Perl interpreter if you | |
644 | want to implement really complicated things. | |
902b9dbf | 645 | |
04c692a8 DR |
646 | Whenever possible, new features should be prototyped in a CPAN module |
647 | before they will be considered for the core. | |
902b9dbf | 648 | |
04c692a8 | 649 | =head3 Is the feature generic enough? |
902b9dbf | 650 | |
04c692a8 DR |
651 | Is this something that only the submitter wants added to the language, |
652 | or is it broadly useful? Sometimes, instead of adding a feature with a | |
653 | tight focus, the porters might decide to wait until someone implements | |
654 | the more generalized feature. | |
902b9dbf | 655 | |
04c692a8 | 656 | =head3 Does it potentially introduce new bugs? |
902b9dbf | 657 | |
04c692a8 DR |
658 | Radical rewrites of large chunks of the Perl interpreter have the |
659 | potential to introduce new bugs. | |
902b9dbf | 660 | |
04c692a8 | 661 | =head3 How big is it? |
902b9dbf | 662 | |
531e2078 | 663 | The smaller and more localized the change, the better. Similarly, a |
04c692a8 | 664 | series of small patches is greatly preferred over a single large patch. |
902b9dbf | 665 | |
04c692a8 | 666 | =head3 Does it preclude other desirable features? |
902b9dbf | 667 | |
04c692a8 | 668 | A patch is likely to be rejected if it closes off future avenues of |
531e2078 | 669 | development. For instance, a patch that placed a true and final |
04c692a8 DR |
670 | interpretation on prototypes is likely to be rejected because there are |
671 | still options for the future of prototypes that haven't been addressed. | |
902b9dbf | 672 | |
04c692a8 | 673 | =head3 Is the implementation robust? |
902b9dbf | 674 | |
04c692a8 | 675 | Good patches (tight code, complete, correct) stand more chance of going |
531e2078 | 676 | in. Sloppy or incorrect patches might be placed on the back burner |
04c692a8 DR |
677 | until the pumpking has time to fix, or might be discarded altogether |
678 | without further notice. | |
902b9dbf | 679 | |
04c692a8 | 680 | =head3 Is the implementation generic enough to be portable? |
902b9dbf | 681 | |
531e2078 | 682 | The worst patches make use of system-specific features. It's highly |
04c692a8 DR |
683 | unlikely that non-portable additions to the Perl language will be |
684 | accepted. | |
902b9dbf | 685 | |
04c692a8 | 686 | =head3 Is the implementation tested? |
902b9dbf | 687 | |
04c692a8 DR |
688 | Patches which change behaviour (fixing bugs or introducing new |
689 | features) must include regression tests to verify that everything works | |
690 | as expected. | |
902b9dbf | 691 | |
04c692a8 DR |
692 | Without tests provided by the original author, how can anyone else |
693 | changing perl in the future be sure that they haven't unwittingly | |
694 | broken the behaviour the patch implements? And without tests, how can | |
695 | the patch's author be confident that his/her hard work put into the | |
696 | patch won't be accidentally thrown away by someone in the future? | |
902b9dbf | 697 | |
04c692a8 | 698 | =head3 Is there enough documentation? |
902b9dbf | 699 | |
04c692a8 | 700 | Patches without documentation are probably ill-thought out or |
531e2078 | 701 | incomplete. No features can be added or changed without documentation, |
04c692a8 DR |
702 | so submitting a patch for the appropriate pod docs as well as the |
703 | source code is important. | |
902b9dbf | 704 | |
04c692a8 | 705 | =head3 Is there another way to do it? |
902b9dbf | 706 | |
04c692a8 | 707 | Larry said "Although the Perl Slogan is I<There's More Than One Way to |
531e2078 | 708 | Do It>, I hesitate to make 10 ways to do something". This is a tricky |
04c692a8 DR |
709 | heuristic to navigate, though--one man's essential addition is another |
710 | man's pointless cruft. | |
902b9dbf | 711 | |
04c692a8 | 712 | =head3 Does it create too much work? |
902b9dbf | 713 | |
04c692a8 DR |
714 | Work for the pumpking, work for Perl programmers, work for module |
715 | authors, ... Perl is supposed to be easy. | |
902b9dbf | 716 | |
04c692a8 | 717 | =head3 Patches speak louder than words |
902b9dbf | 718 | |
531e2078 | 719 | Working code is always preferred to pie-in-the-sky ideas. A patch to |
04c692a8 DR |
720 | add a feature stands a much higher chance of making it to the language |
721 | than does a random feature request, no matter how fervently argued the | |
a44b8c28 S |
722 | request might be. This ties into "Will it be useful?", as the fact |
723 | that someone took the time to make the patch demonstrates a strong | |
724 | desire for the feature. | |
c406981e | 725 | |
04c692a8 | 726 | =head1 TESTING |
c406981e | 727 | |
04c692a8 DR |
728 | The core uses the same testing style as the rest of Perl, a simple |
729 | "ok/not ok" run through Test::Harness, but there are a few special | |
730 | considerations. | |
c406981e | 731 | |
531e2078 | 732 | There are three ways to write a test in the core: L<Test::More>, |
a44b8c28 S |
733 | F<t/test.pl> and ad hoc C<print $test ? "ok 42\n" : "not ok 42\n">. |
734 | The decision of which to use depends on what part of the test suite | |
735 | you're working on. This is a measure to prevent a high-level failure | |
736 | (such as Config.pm breaking) from causing basic functionality tests to | |
737 | fail. | |
c406981e | 738 | |
04c692a8 DR |
739 | The F<t/test.pl> library provides some of the features of |
740 | L<Test::More>, but avoids loading most modules and uses as few core | |
741 | features as possible. | |
902b9dbf | 742 | |
9e6670f3 DR |
743 | If you write your own test, use the L<Test Anything |
744 | Protocol|http://testanything.org>. | |
902b9dbf MLF |
745 | |
746 | =over 4 | |
747 | ||
bb52f720 | 748 | =item * F<t/base>, F<t/comp> and F<t/opbasic> |
902b9dbf | 749 | |
04c692a8 | 750 | Since we don't know if require works, or even subroutines, use ad hoc |
531e2078 | 751 | tests for these three. Step carefully to avoid using the feature being |
a44b8c28 S |
752 | tested. Tests in F<t/opbasic>, for instance, have been placed there |
753 | rather than in F<t/op> because they test functionality which | |
754 | F<t/test.pl> presumes has already been demonstrated to work. | |
902b9dbf | 755 | |
a8d15a22 | 756 | =item * F<t/cmd>, F<t/run>, F<t/io> and F<t/op> |
902b9dbf | 757 | |
04c692a8 DR |
758 | Now that basic require() and subroutines are tested, you can use the |
759 | F<t/test.pl> library. | |
902b9dbf | 760 | |
a8d15a22 | 761 | You can also use certain libraries like Config conditionally, but be |
04c692a8 | 762 | sure to skip the test gracefully if it's not there. |
902b9dbf | 763 | |
04c692a8 | 764 | =item * Everything else |
902b9dbf | 765 | |
04c692a8 | 766 | Now that the core of Perl is tested, L<Test::More> can and should be |
531e2078 | 767 | used. You can also use the full suite of core modules in the tests. |
902b9dbf MLF |
768 | |
769 | =back | |
770 | ||
a8d15a22 | 771 | When you say "make test", Perl uses the F<t/TEST> program to run the |
a44b8c28 S |
772 | test suite (except under Win32 where it uses F<t/harness> instead). |
773 | All tests are run from the F<t/> directory, B<not> the directory which | |
774 | contains the test. This causes some problems with the tests in | |
775 | F<lib/>, so here's some opportunity for some patching. | |
902b9dbf | 776 | |
531e2078 | 777 | You must be triply conscious of cross-platform concerns. This usually |
04c692a8 DR |
778 | boils down to using L<File::Spec> and avoiding things like C<fork()> |
779 | and C<system()> unless absolutely necessary. | |
7a834142 | 780 | |
04c692a8 | 781 | =head2 Special C<make test> targets |
07aa3531 | 782 | |
04c692a8 | 783 | There are various special make targets that can be used to test Perl |
531e2078 FC |
784 | slightly differently than the standard "test" target. Not all them are |
785 | expected to give a 100% success rate. Many of them have several | |
04c692a8 DR |
786 | aliases, and many of them are not available on certain operating |
787 | systems. | |
07aa3531 | 788 | |
04c692a8 | 789 | =over 4 |
d44161bf | 790 | |
04c692a8 | 791 | =item * test_porting |
7a834142 | 792 | |
04c692a8 DR |
793 | This runs some basic sanity tests on the source tree and helps catch |
794 | basic errors before you submit a patch. | |
7a834142 | 795 | |
04c692a8 | 796 | =item * minitest |
51a35ef1 | 797 | |
04c692a8 DR |
798 | Run F<miniperl> on F<t/base>, F<t/comp>, F<t/cmd>, F<t/run>, F<t/io>, |
799 | F<t/op>, F<t/uni> and F<t/mro> tests. | |
51a35ef1 | 800 | |
499cea6b | 801 | =item * test.valgrind check.valgrind |
51a35ef1 | 802 | |
04c692a8 | 803 | (Only in Linux) Run all the tests using the memory leak + naughty |
531e2078 | 804 | memory access tool "valgrind". The log files will be named |
04c692a8 | 805 | F<testname.valgrind>. |
83f0ef60 | 806 | |
04c692a8 | 807 | =item * test_harness |
83f0ef60 | 808 | |
04c692a8 | 809 | Run the test suite with the F<t/harness> controlling program, instead |
531e2078 | 810 | of F<t/TEST>. F<t/harness> is more sophisticated, and uses the |
04c692a8 | 811 | L<Test::Harness> module, thus using this test target supposes that perl |
531e2078 | 812 | mostly works. The main advantage for our purposes is that it prints a |
a44b8c28 S |
813 | detailed summary of failed tests at the end. Also, unlike F<t/TEST>, |
814 | it doesn't redirect stderr to stdout. | |
83f0ef60 | 815 | |
04c692a8 DR |
816 | Note that under Win32 F<t/harness> is always used instead of F<t/TEST>, |
817 | so there is no special "test_harness" target. | |
83f0ef60 | 818 | |
04c692a8 DR |
819 | Under Win32's "test" target you may use the TEST_SWITCHES and |
820 | TEST_FILES environment variables to control the behaviour of | |
531e2078 | 821 | F<t/harness>. This means you can say |
83f0ef60 | 822 | |
04c692a8 DR |
823 | nmake test TEST_FILES="op/*.t" |
824 | nmake test TEST_SWITCHES="-torture" TEST_FILES="op/*.t" | |
83f0ef60 | 825 | |
78087e0a R |
826 | =item * test-notty test_notty |
827 | ||
828 | Sets PERL_SKIP_TTY_TEST to true before running normal test. | |
829 | ||
83f0ef60 JH |
830 | =back |
831 | ||
04c692a8 | 832 | =head2 Parallel tests |
83f0ef60 | 833 | |
04c692a8 | 834 | The core distribution can now run its regression tests in parallel on |
531e2078 | 835 | Unix-like platforms. Instead of running C<make test>, set C<TEST_JOBS> |
04c692a8 | 836 | in your environment to the number of tests to run in parallel, and run |
531e2078 | 837 | C<make test_harness>. On a Bourne-like shell, this can be done as |
07aa3531 | 838 | |
04c692a8 | 839 | TEST_JOBS=3 make test_harness # Run 3 tests in parallel |
07aa3531 | 840 | |
04c692a8 DR |
841 | An environment variable is used, rather than parallel make itself, |
842 | because L<TAP::Harness> needs to be able to schedule individual | |
843 | non-conflicting test scripts itself, and there is no standard interface | |
844 | to C<make> utilities to interact with their job schedulers. | |
51a35ef1 | 845 | |
9e6670f3 | 846 | Note that currently some test scripts may fail when run in parallel |
a44b8c28 S |
847 | (most notably F<ext/IO/t/io_dir.t>). If necessary, run just the |
848 | failing scripts again sequentially and see if the failures go away. | |
51a35ef1 | 849 | |
04c692a8 | 850 | =head2 Running tests by hand |
51a35ef1 | 851 | |
9e6670f3 DR |
852 | You can run part of the test suite by hand by using one of the |
853 | following commands from the F<t/> directory: | |
51a35ef1 | 854 | |
04c692a8 | 855 | ./perl -I../lib TEST list-of-.t-files |
51a35ef1 | 856 | |
04c692a8 | 857 | or |
51a35ef1 | 858 | |
04c692a8 | 859 | ./perl -I../lib harness list-of-.t-files |
51a35ef1 | 860 | |
a8d15a22 | 861 | (If you don't specify test scripts, the whole test suite will be run.) |
51a35ef1 | 862 | |
04c692a8 | 863 | =head2 Using F<t/harness> for testing |
51a35ef1 | 864 | |
9e6670f3 | 865 | If you use C<harness> for testing, you have several command line |
531e2078 | 866 | options available to you. The arguments are as follows, and are in the |
9e6670f3 | 867 | order that they must appear if used together. |
51a35ef1 | 868 | |
04c692a8 DR |
869 | harness -v -torture -re=pattern LIST OF FILES TO TEST |
870 | harness -v -torture -re LIST OF PATTERNS TO MATCH | |
07aa3531 | 871 | |
a8d15a22 | 872 | If C<LIST OF FILES TO TEST> is omitted, the file list is obtained from |
531e2078 | 873 | the manifest. The file list may include shell wildcards which will be |
04c692a8 | 874 | expanded out. |
07aa3531 | 875 | |
04c692a8 | 876 | =over 4 |
4ae3d70a | 877 | |
04c692a8 | 878 | =item * -v |
4ae3d70a | 879 | |
04c692a8 DR |
880 | Run the tests under verbose mode so you can see what tests were run, |
881 | and debug output. | |
51a35ef1 | 882 | |
04c692a8 | 883 | =item * -torture |
4ae3d70a | 884 | |
04c692a8 | 885 | Run the torture tests as well as the normal set. |
4ae3d70a | 886 | |
04c692a8 | 887 | =item * -re=PATTERN |
6c41479b | 888 | |
a44b8c28 S |
889 | Filter the file list so that all the test files run match PATTERN. |
890 | Note that this form is distinct from the B<-re LIST OF PATTERNS> form | |
891 | below in that it allows the file list to be provided as well. | |
6c41479b | 892 | |
04c692a8 | 893 | =item * -re LIST OF PATTERNS |
6c41479b | 894 | |
04c692a8 | 895 | Filter the file list so that all the test files run match |
531e2078 | 896 | /(LIST|OF|PATTERNS)/. Note that with this form the patterns are joined |
04c692a8 DR |
897 | by '|' and you cannot supply a list of files, instead the test files |
898 | are obtained from the MANIFEST. | |
6c41479b | 899 | |
04c692a8 | 900 | =back |
6c41479b | 901 | |
04c692a8 | 902 | You can run an individual test by a command similar to |
6c41479b | 903 | |
a8d15a22 | 904 | ./perl -I../lib path/to/foo.t |
6c41479b | 905 | |
04c692a8 DR |
906 | except that the harnesses set up some environment variables that may |
907 | affect the execution of the test: | |
6c41479b JH |
908 | |
909 | =over 4 | |
910 | ||
04c692a8 | 911 | =item * PERL_CORE=1 |
6c41479b | 912 | |
a8d15a22 | 913 | indicates that we're running this test as part of the perl core test |
531e2078 | 914 | suite. This is useful for modules that have a dual life on CPAN. |
6c41479b | 915 | |
04c692a8 | 916 | =item * PERL_DESTRUCT_LEVEL=2 |
6c41479b | 917 | |
04c692a8 | 918 | is set to 2 if it isn't set already (see |
a8d15a22 | 919 | L<perlhacktips/PERL_DESTRUCT_LEVEL>). |
6c41479b | 920 | |
04c692a8 | 921 | =item * PERL |
6c41479b | 922 | |
04c692a8 DR |
923 | (used only by F<t/TEST>) if set, overrides the path to the perl |
924 | executable that should be used to run the tests (the default being | |
925 | F<./perl>). | |
6c41479b | 926 | |
04c692a8 | 927 | =item * PERL_SKIP_TTY_TEST |
6c41479b | 928 | |
a44b8c28 S |
929 | if set, tells to skip the tests that need a terminal. It's actually |
930 | set automatically by the Makefile, but can also be forced artificially | |
931 | by running 'make test_notty'. | |
6c41479b | 932 | |
04c692a8 | 933 | =back |
6c41479b | 934 | |
04c692a8 | 935 | =head3 Other environment variables that may influence tests |
6c41479b | 936 | |
04c692a8 | 937 | =over 4 |
6c41479b | 938 | |
04c692a8 | 939 | =item * PERL_TEST_Net_Ping |
6c41479b | 940 | |
04c692a8 | 941 | Setting this variable runs all the Net::Ping modules tests, otherwise |
531e2078 | 942 | some tests that interact with the outside world are skipped. See |
04c692a8 | 943 | L<perl58delta>. |
6c41479b | 944 | |
04c692a8 | 945 | =item * PERL_TEST_NOVREXX |
cce04beb | 946 | |
04c692a8 | 947 | Setting this variable skips the vrexx.t tests for OS2::REXX. |
cce04beb | 948 | |
04c692a8 | 949 | =item * PERL_TEST_NUMCONVERTS |
cce04beb | 950 | |
04c692a8 | 951 | This sets a variable in op/numconvert.t. |
cce04beb | 952 | |
ff5db609 TC |
953 | =item * PERL_TEST_MEMORY |
954 | ||
955 | Setting this variable includes the tests in F<t/bigmem/>. This should | |
a44b8c28 S |
956 | be set to the number of gigabytes of memory available for testing, eg. |
957 | C<PERL_TEST_MEMORY=4> indicates that tests that require 4GiB of | |
ff5db609 TC |
958 | available memory can be run safely. |
959 | ||
04c692a8 | 960 | =back |
cce04beb | 961 | |
04c692a8 DR |
962 | See also the documentation for the Test and Test::Harness modules, for |
963 | more environment variables that affect testing. | |
cce04beb | 964 | |
04c692a8 | 965 | =head1 MORE READING FOR GUTS HACKERS |
cce04beb | 966 | |
04c692a8 | 967 | To hack on the Perl guts, you'll need to read the following things: |
cce04beb | 968 | |
04c692a8 | 969 | =over 4 |
cce04beb | 970 | |
04c692a8 | 971 | =item * L<perlsource> |
b8ddf6b3 | 972 | |
531e2078 | 973 | An overview of the Perl source tree. This will help you find the files |
04c692a8 | 974 | you're looking for. |
b8ddf6b3 | 975 | |
04c692a8 | 976 | =item * L<perlinterp> |
b8ddf6b3 | 977 | |
04c692a8 DR |
978 | An overview of the Perl interpreter source code and some details on how |
979 | Perl does what it does. | |
b8ddf6b3 | 980 | |
04c692a8 | 981 | =item * L<perlhacktut> |
b8ddf6b3 | 982 | |
04c692a8 | 983 | This document walks through the creation of a small patch to Perl's C |
531e2078 | 984 | code. If you're just getting started with Perl core hacking, this will |
04c692a8 | 985 | help you understand how it works. |
b8ddf6b3 | 986 | |
04c692a8 | 987 | =item * L<perlhacktips> |
b8ddf6b3 | 988 | |
531e2078 | 989 | More details on hacking the Perl core. This document focuses on lower |
04c692a8 DR |
990 | level details such as how to write tests, compilation issues, |
991 | portability, debugging, etc. | |
b8ddf6b3 | 992 | |
04c692a8 | 993 | If you plan on doing serious C hacking, make sure to read this. |
b8ddf6b3 | 994 | |
04c692a8 | 995 | =item * L<perlguts> |
b8ddf6b3 | 996 | |
04c692a8 | 997 | This is of paramount importance, since it's the documentation of what |
531e2078 | 998 | goes where in the Perl source. Read it over a couple of times and it |
04c692a8 DR |
999 | might start to make sense - don't worry if it doesn't yet, because the |
1000 | best way to study it is to read it in conjunction with poking at Perl | |
1001 | source, and we'll do that later on. | |
b8ddf6b3 | 1002 | |
04c692a8 DR |
1003 | Gisle Aas's "illustrated perlguts", also known as I<illguts>, has very |
1004 | helpful pictures: | |
9965345d | 1005 | |
04c692a8 | 1006 | L<http://search.cpan.org/dist/illguts/> |
9965345d | 1007 | |
04c692a8 | 1008 | =item * L<perlxstut> and L<perlxs> |
f1fac472 | 1009 | |
04c692a8 DR |
1010 | A working knowledge of XSUB programming is incredibly useful for core |
1011 | hacking; XSUBs use techniques drawn from the PP code, the portion of | |
531e2078 | 1012 | the guts that actually executes a Perl program. It's a lot gentler to |
04c692a8 DR |
1013 | learn those techniques from simple examples and explanation than from |
1014 | the core itself. | |
f1fac472 | 1015 | |
04c692a8 | 1016 | =item * L<perlapi> |
f1fac472 | 1017 | |
04c692a8 DR |
1018 | The documentation for the Perl API explains what some of the internal |
1019 | functions do, as well as the many macros used in the source. | |
f1fac472 | 1020 | |
04c692a8 | 1021 | =item * F<Porting/pumpkin.pod> |
f1fac472 | 1022 | |
04c692a8 DR |
1023 | This is a collection of words of wisdom for a Perl porter; some of it |
1024 | is only useful to the pumpkin holder, but most of it applies to anyone | |
1025 | wanting to go about Perl development. | |
f1fac472 | 1026 | |
04c692a8 | 1027 | =back |
f1fac472 | 1028 | |
04c692a8 | 1029 | =head1 CPAN TESTERS AND PERL SMOKERS |
f1fac472 | 1030 | |
04c692a8 DR |
1031 | The CPAN testers ( http://testers.cpan.org/ ) are a group of volunteers |
1032 | who test CPAN modules on a variety of platforms. | |
b8ddf6b3 | 1033 | |
a8d15a22 | 1034 | Perl Smokers ( http://www.nntp.perl.org/group/perl.daily-build/ and |
04c692a8 DR |
1035 | http://www.nntp.perl.org/group/perl.daily-build.reports/ ) |
1036 | automatically test Perl source releases on platforms with various | |
1037 | configurations. | |
f1fac472 | 1038 | |
531e2078 | 1039 | Both efforts welcome volunteers. In order to get involved in smoke |
04c692a8 | 1040 | testing of the perl itself visit |
531e2078 | 1041 | L<http://search.cpan.org/dist/Test-Smoke/>. In order to start smoke |
04c692a8 DR |
1042 | testing CPAN modules visit |
1043 | L<http://search.cpan.org/dist/CPANPLUS-YACSmoke/> or | |
1044 | L<http://search.cpan.org/dist/minismokebox/> or | |
1045 | L<http://search.cpan.org/dist/CPAN-Reporter/>. | |
f1fac472 | 1046 | |
04c692a8 | 1047 | =head1 WHAT NEXT? |
a422fd2d | 1048 | |
04c692a8 DR |
1049 | If you've read all the documentation in the document and the ones |
1050 | listed above, you're more than ready to hack on Perl. | |
a422fd2d | 1051 | |
04c692a8 | 1052 | Here's some more recommendations |
a422fd2d | 1053 | |
04c692a8 | 1054 | =over 4 |
a422fd2d SC |
1055 | |
1056 | =item * | |
1057 | ||
1058 | Subscribe to perl5-porters, follow the patches and try and understand | |
1059 | them; don't be afraid to ask if there's a portion you're not clear on - | |
1060 | who knows, you may unearth a bug in the patch... | |
1061 | ||
1062 | =item * | |
1063 | ||
04c692a8 | 1064 | Do read the README associated with your operating system, e.g. |
531e2078 | 1065 | README.aix on the IBM AIX OS. Don't hesitate to supply patches to that |
04c692a8 | 1066 | README if you find anything missing or changed over a new OS release. |
a1f349fd MB |
1067 | |
1068 | =item * | |
1069 | ||
a422fd2d | 1070 | Find an area of Perl that seems interesting to you, and see if you can |
a44b8c28 S |
1071 | work out how it works. Scan through the source, and step over it in |
1072 | the debugger. Play, poke, investigate, fiddle! You'll probably get to | |
04c692a8 DR |
1073 | understand not just your chosen area but a much wider range of |
1074 | F<perl>'s activity as well, and probably sooner than you'd think. | |
a422fd2d SC |
1075 | |
1076 | =back | |
1077 | ||
04c692a8 | 1078 | =head2 "The Road goes ever on and on, down from the door where it began." |
a422fd2d | 1079 | |
04c692a8 | 1080 | If you can do these things, you've started on the long road to Perl |
531e2078 | 1081 | porting. Thanks for wanting to help make Perl better - and happy |
04c692a8 | 1082 | hacking! |
a422fd2d | 1083 | |
4ac71550 TC |
1084 | =head2 Metaphoric Quotations |
1085 | ||
1086 | If you recognized the quote about the Road above, you're in luck. | |
1087 | ||
04c692a8 | 1088 | Most software projects begin each file with a literal description of |
531e2078 | 1089 | each file's purpose. Perl instead begins each with a literary allusion |
04c692a8 | 1090 | to that file's purpose. |
4ac71550 | 1091 | |
04c692a8 | 1092 | Like chapters in many books, all top-level Perl source files (along |
9e6670f3 DR |
1093 | with a few others here and there) begin with an epigrammatic |
1094 | inscription that alludes, indirectly and metaphorically, to the | |
1095 | material you're about to read. | |
4ac71550 | 1096 | |
a8d15a22 | 1097 | Quotations are taken from writings of J.R.R. Tolkien pertaining to his |
531e2078 | 1098 | Legendarium, almost always from I<The Lord of the Rings>. Chapters and |
4ac71550 TC |
1099 | page numbers are given using the following editions: |
1100 | ||
1101 | =over 4 | |
1102 | ||
04c692a8 | 1103 | =item * |
4ac71550 | 1104 | |
531e2078 | 1105 | I<The Hobbit>, by J.R.R. Tolkien. The hardcover, 70th-anniversary |
04c692a8 DR |
1106 | edition of 2007 was used, published in the UK by Harper Collins |
1107 | Publishers and in the US by the Houghton Mifflin Company. | |
4ac71550 TC |
1108 | |
1109 | =item * | |
1110 | ||
531e2078 | 1111 | I<The Lord of the Rings>, by J.R.R. Tolkien. The hardcover, |
04c692a8 DR |
1112 | 50th-anniversary edition of 2004 was used, published in the UK by |
1113 | Harper Collins Publishers and in the US by the Houghton Mifflin | |
1114 | Company. | |
4ac71550 TC |
1115 | |
1116 | =item * | |
1117 | ||
04c692a8 DR |
1118 | I<The Lays of Beleriand>, by J.R.R. Tolkien and published posthumously |
1119 | by his son and literary executor, C.J.R. Tolkien, being the 3rd of the | |
531e2078 | 1120 | 12 volumes in Christopher's mammoth I<History of Middle Earth>. Page |
04c692a8 DR |
1121 | numbers derive from the hardcover edition, first published in 1983 by |
1122 | George Allen & Unwin; no page numbers changed for the special 3-volume | |
1123 | omnibus edition of 2002 or the various trade-paper editions, all again | |
1124 | now by Harper Collins or Houghton Mifflin. | |
4ac71550 TC |
1125 | |
1126 | =back | |
1127 | ||
04c692a8 DR |
1128 | Other JRRT books fair game for quotes would thus include I<The |
1129 | Adventures of Tom Bombadil>, I<The Silmarillion>, I<Unfinished Tales>, | |
1130 | and I<The Tale of the Children of Hurin>, all but the first | |
531e2078 | 1131 | posthumously assembled by CJRT. But I<The Lord of the Rings> itself is |
04c692a8 DR |
1132 | perfectly fine and probably best to quote from, provided you can find a |
1133 | suitable quote there. | |
4ac71550 | 1134 | |
04c692a8 DR |
1135 | So if you were to supply a new, complete, top-level source file to add |
1136 | to Perl, you should conform to this peculiar practice by yourself | |
1137 | selecting an appropriate quotation from Tolkien, retaining the original | |
1138 | spelling and punctuation and using the same format the rest of the | |
531e2078 | 1139 | quotes are in. Indirect and oblique is just fine; remember, it's a |
04c692a8 | 1140 | metaphor, so being meta is, after all, what it's for. |
4ac71550 | 1141 | |
e8cd7eae GS |
1142 | =head1 AUTHOR |
1143 | ||
04c692a8 DR |
1144 | This document was originally written by Nathan Torkington, and is |
1145 | maintained by the perl5-porters mailing list. | |
b16c2e4a | 1146 |