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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 | |
eb9df707 KW |
41 | Hack, hack, hack. Keep in mind that Perl runs on many different |
42 | platforms, with different operating systems that have different | |
43 | capabilities, different filesystem organizations, and even different | |
44 | character sets. L<perlhacktips> gives advice on this. | |
7205a85d | 45 | |
04c692a8 | 46 | =item * Test your change |
e018f8be | 47 | |
04c692a8 | 48 | You can run all the tests with the following commands: |
b26492ee | 49 | |
04c692a8 DR |
50 | % ./Configure -des -Dusedevel |
51 | % make test | |
7205a85d | 52 | |
04c692a8 | 53 | Keep hacking until the tests pass. |
b26492ee | 54 | |
04c692a8 | 55 | =item * Commit your change |
e018f8be | 56 | |
b6538e4f | 57 | Committing your work will save the change I<on your local system>: |
7205a85d | 58 | |
04c692a8 | 59 | % git commit -a -m 'Commit message goes here' |
e018f8be | 60 | |
04c692a8 | 61 | Make sure the commit message describes your change in a single |
531e2078 | 62 | sentence. For example, "Fixed spelling errors in perlhack.pod". |
e018f8be | 63 | |
04c692a8 | 64 | =item * Send your change to perlbug |
7a834142 | 65 | |
04c692a8 DR |
66 | The next step is to submit your patch to the Perl core ticket system |
67 | via email. | |
7a834142 | 68 | |
84788b0a | 69 | If your changes are in a single git commit, run the following commands |
e7769b3e | 70 | to generate the patch file and attach it to your bug report: |
e018f8be | 71 | |
e7769b3e CB |
72 | % git format-patch -1 |
73 | % ./perl -Ilib utils/perlbug -p 0001-*.patch | |
e018f8be | 74 | |
04c692a8 | 75 | The perlbug program will ask you a few questions about your email |
531e2078 | 76 | address and the patch you're submitting. Once you've answered them it |
84b19098 | 77 | will submit your patch via email. |
e018f8be | 78 | |
e7769b3e CB |
79 | If your changes are in multiple commits, generate a patch file for each |
80 | one and provide them to perlbug's C<-p> option separated by commas: | |
2d1c9392 | 81 | |
e7769b3e CB |
82 | % git format-patch -3 |
83 | % ./perl -Ilib utils/perlbug -p 0001-fix1.patch,0002-fix2.patch,\ | |
84 | > 0003-fix3.patch | |
2d1c9392 | 85 | |
e7769b3e | 86 | When prompted, pick a subject that summarizes your changes. |
2d1c9392 | 87 | |
04c692a8 | 88 | =item * Thank you |
e018f8be | 89 | |
04c692a8 DR |
90 | The porters appreciate the time you spent helping to make Perl better. |
91 | Thank you! | |
e018f8be | 92 | |
e99cf3f0 S |
93 | =item * Next time |
94 | ||
95 | The next time you wish to make a patch, you need to start from the | |
30454452 | 96 | latest perl in a pristine state. Check you don't have any local changes |
e99cf3f0 S |
97 | or added files in your perl check-out which you wish to keep, then run |
98 | these commands: | |
99 | ||
100 | % git pull | |
101 | % git reset --hard origin/blead | |
102 | % git clean -dxf | |
103 | ||
cce04beb | 104 | =back |
e018f8be | 105 | |
04c692a8 | 106 | =head1 BUG REPORTING |
cc0710ff | 107 | |
9e6670f3 | 108 | If you want to report a bug in Perl, you must use the F<perlbug> |
531e2078 | 109 | command line tool. This tool will ensure that your bug report includes |
9e6670f3 | 110 | all the relevant system and configuration information. |
7205a85d | 111 | |
04c692a8 | 112 | To browse existing Perl bugs and patches, you can use the web interface |
a8d15a22 | 113 | at L<http://rt.perl.org/>. |
244d9cb7 | 114 | |
04c692a8 | 115 | Please check the archive of the perl5-porters list (see below) and/or |
531e2078 | 116 | the bug tracking system before submitting a bug report. Often, you'll |
04c692a8 | 117 | find that the bug has been reported already. |
244d9cb7 | 118 | |
04c692a8 | 119 | You can log in to the bug tracking system and comment on existing bug |
531e2078 FC |
120 | reports. If you have additional information regarding an existing bug, |
121 | please add it. This will help the porters fix the bug. | |
7205a85d | 122 | |
04c692a8 | 123 | =head1 PERL 5 PORTERS |
7205a85d | 124 | |
04c692a8 | 125 | The perl5-porters (p5p) mailing list is where the Perl standard |
531e2078 | 126 | distribution is maintained and developed. The people who maintain Perl |
9e6670f3 DR |
127 | are also referred to as the "Perl 5 Porters", "p5p" or just the |
128 | "porters". | |
a75f557c | 129 | |
04c692a8 | 130 | A searchable archive of the list is available at |
586e992d | 131 | L<http://markmail.org/search/?q=perl5-porters>. There is also an archive at |
04c692a8 | 132 | L<http://archive.develooper.com/perl5-porters@perl.org/>. |
7205a85d | 133 | |
04c692a8 | 134 | =head2 perl-changes mailing list |
7205a85d | 135 | |
04c692a8 DR |
136 | The perl5-changes mailing list receives a copy of each patch that gets |
137 | submitted to the maintenance and development branches of the perl | |
531e2078 | 138 | repository. See L<http://lists.perl.org/list/perl5-changes.html> for |
04c692a8 | 139 | subscription and archive information. |
244d9cb7 | 140 | |
37bf3a91 DR |
141 | =head2 #p5p on IRC |
142 | ||
143 | Many porters are also active on the L<irc://irc.perl.org/#p5p> channel. | |
144 | Feel free to join the channel and ask questions about hacking on the | |
145 | Perl core. | |
146 | ||
04c692a8 | 147 | =head1 GETTING THE PERL SOURCE |
244d9cb7 | 148 | |
04c692a8 | 149 | All of Perl's source code is kept centrally in a Git repository at |
a44b8c28 S |
150 | I<perl5.git.perl.org>. The repository contains many Perl revisions |
151 | from Perl 1 onwards and all the revisions from Perforce, the previous | |
04c692a8 | 152 | version control system. |
244d9cb7 | 153 | |
04c692a8 DR |
154 | For much more detail on using git with the Perl repository, please see |
155 | L<perlgit>. | |
244d9cb7 | 156 | |
04c692a8 | 157 | =head2 Read access via Git |
244d9cb7 | 158 | |
531e2078 | 159 | You will need a copy of Git for your computer. You can fetch a copy of |
04c692a8 | 160 | the repository using the git protocol: |
244d9cb7 | 161 | |
04c692a8 | 162 | % git clone git://perl5.git.perl.org/perl.git perl |
244d9cb7 | 163 | |
04c692a8 DR |
164 | This clones the repository and makes a local copy in the F<perl> |
165 | directory. | |
7205a85d | 166 | |
04c692a8 DR |
167 | If you cannot use the git protocol for firewall reasons, you can also |
168 | clone via http, though this is much slower: | |
7205a85d | 169 | |
04c692a8 | 170 | % git clone http://perl5.git.perl.org/perl.git perl |
7205a85d | 171 | |
04c692a8 | 172 | =head2 Read access via the web |
7205a85d | 173 | |
531e2078 | 174 | You may access the repository over the web. This allows you to browse |
04c692a8 | 175 | the tree, see recent commits, subscribe to RSS feeds for the changes, |
531e2078 FC |
176 | search for particular commits and more. You may access it at |
177 | L<http://perl5.git.perl.org/perl.git>. A mirror of the repository is | |
b0959619 | 178 | found at L<https://github.com/Perl/perl5>. |
7205a85d | 179 | |
04c692a8 | 180 | =head2 Read access via rsync |
7205a85d | 181 | |
04c692a8 DR |
182 | You can also choose to use rsync to get a copy of the current source |
183 | tree for the bleadperl branch and all maintenance branches: | |
7205a85d | 184 | |
7eac65da S |
185 | % rsync -avz rsync://perl5.git.perl.org/perl-current . |
186 | % rsync -avz rsync://perl5.git.perl.org/perl-5.12.x . | |
187 | % rsync -avz rsync://perl5.git.perl.org/perl-5.10.x . | |
188 | % rsync -avz rsync://perl5.git.perl.org/perl-5.8.x . | |
189 | % rsync -avz rsync://perl5.git.perl.org/perl-5.6.x . | |
190 | % rsync -avz rsync://perl5.git.perl.org/perl-5.005xx . | |
7205a85d | 191 | |
a8d15a22 | 192 | (Add the C<--delete> option to remove leftover files.) |
7205a85d | 193 | |
04c692a8 | 194 | To get a full list of the available sync points: |
7205a85d | 195 | |
7eac65da | 196 | % rsync perl5.git.perl.org:: |
7205a85d | 197 | |
04c692a8 | 198 | =head2 Write access via git |
7205a85d | 199 | |
04c692a8 DR |
200 | If you have a commit bit, please see L<perlgit> for more details on |
201 | using git. | |
7205a85d | 202 | |
04c692a8 | 203 | =head1 PATCHING PERL |
7205a85d | 204 | |
04c692a8 | 205 | If you're planning to do more extensive work than a single small fix, |
531e2078 | 206 | we encourage you to read the documentation below. This will help you |
04c692a8 DR |
207 | focus your work and make your patches easier to incorporate into the |
208 | Perl source. | |
244d9cb7 | 209 | |
04c692a8 | 210 | =head2 Submitting patches |
244d9cb7 | 211 | |
531e2078 FC |
212 | If you have a small patch to submit, please submit it via perlbug. You |
213 | can also send email directly to perlbug@perl.org. Please note that | |
04c692a8 DR |
214 | messages sent to perlbug may be held in a moderation queue, so you |
215 | won't receive a response immediately. | |
244d9cb7 | 216 | |
04c692a8 | 217 | You'll know your submission has been processed when you receive an |
531e2078 FC |
218 | email from our ticket tracking system. This email will give you a |
219 | ticket number. Once your patch has made it to the ticket tracking | |
04c692a8 | 220 | system, it will also be sent to the perl5-porters@perl.org list. |
244d9cb7 | 221 | |
531e2078 | 222 | Patches are reviewed and discussed on the p5p list. Simple, |
04c692a8 DR |
223 | uncontroversial patches will usually be applied without any discussion. |
224 | When the patch is applied, the ticket will be updated and you will | |
531e2078 | 225 | receive email. In addition, an email will be sent to the p5p list. |
244d9cb7 | 226 | |
531e2078 | 227 | In other cases, the patch will need more work or discussion. That will |
04c692a8 | 228 | happen on the p5p list. |
244d9cb7 | 229 | |
04c692a8 | 230 | You are encouraged to participate in the discussion and advocate for |
531e2078 | 231 | your patch. Sometimes your patch may get lost in the shuffle. It's |
04c692a8 | 232 | appropriate to send a reminder email to p5p if no action has been taken |
531e2078 | 233 | in a month. Please remember that the Perl 5 developers are all |
04c692a8 | 234 | volunteers, and be polite. |
244d9cb7 | 235 | |
04c692a8 | 236 | Changes are always applied directly to the main development branch, |
a44b8c28 | 237 | called "blead". Some patches may be backported to a maintenance |
30454452 | 238 | branch. If you think your patch is appropriate for the maintenance |
839a0e5a | 239 | branch (see L<perlpolicy/MAINTENANCE BRANCHES>), please explain why |
d0bba22e | 240 | when you submit it. |
244d9cb7 | 241 | |
04c692a8 | 242 | =head2 Getting your patch accepted |
244d9cb7 | 243 | |
84c2f6fd DR |
244 | If you are submitting a code patch there are several things that you |
245 | can do to help the Perl 5 Porters accept your patch. | |
244d9cb7 | 246 | |
a126fb62 DR |
247 | =head3 Patch style |
248 | ||
249 | If you used git to check out the Perl source, then using C<git | |
531e2078 | 250 | format-patch> will produce a patch in a style suitable for Perl. The |
a126fb62 | 251 | C<format-patch> command produces one patch file for each commit you |
a44b8c28 S |
252 | made. If you prefer to send a single patch for all commits, you can |
253 | use C<git diff>. | |
a126fb62 | 254 | |
9d440a18 | 255 | % git checkout blead |
a126fb62 DR |
256 | % git pull |
257 | % git diff blead my-branch-name | |
258 | ||
259 | This produces a patch based on the difference between blead and your | |
531e2078 | 260 | current branch. It's important to make sure that blead is up to date |
a126fb62 DR |
261 | before producing the diff, that's why we call C<git pull> first. |
262 | ||
531e2078 | 263 | We strongly recommend that you use git if possible. It will make your |
a126fb62 DR |
264 | life easier, and ours as well. |
265 | ||
266 | However, if you're not using git, you can still produce a suitable | |
531e2078 FC |
267 | patch. You'll need a pristine copy of the Perl source to diff against. |
268 | The porters prefer unified diffs. Using GNU C<diff>, you can produce a | |
a126fb62 DR |
269 | diff like this: |
270 | ||
271 | % diff -Npurd perl.pristine perl.mine | |
272 | ||
273 | Make sure that you C<make realclean> in your copy of Perl to remove any | |
274 | build artifacts, or you may get a confusing result. | |
275 | ||
04c692a8 | 276 | =head3 Commit message |
244d9cb7 | 277 | |
04c692a8 | 278 | As you craft each patch you intend to submit to the Perl core, it's |
531e2078 | 279 | important to write a good commit message. This is especially important |
04c692a8 | 280 | if your submission will consist of a series of commits. |
244d9cb7 | 281 | |
04c692a8 | 282 | The first line of the commit message should be a short description |
531e2078 | 283 | without a period. It should be no longer than the subject line of an |
a8d15a22 | 284 | email, 50 characters being a good rule of thumb. |
f7e1e956 | 285 | |
a8d15a22 | 286 | A lot of Git tools (Gitweb, GitHub, git log --pretty=oneline, ...) will |
04c692a8 DR |
287 | only display the first line (cut off at 50 characters) when presenting |
288 | commit summaries. | |
7cd58830 | 289 | |
04c692a8 DR |
290 | The commit message should include a description of the problem that the |
291 | patch corrects or new functionality that the patch adds. | |
7cd58830 | 292 | |
04c692a8 DR |
293 | As a general rule of thumb, your commit message should help a |
294 | programmer who knows the Perl core quickly understand what you were | |
295 | trying to do, how you were trying to do it, and why the change matters | |
296 | to Perl. | |
7cd58830 | 297 | |
04c692a8 | 298 | =over 4 |
7cd58830 | 299 | |
04c692a8 | 300 | =item * Why |
7cd58830 | 301 | |
04c692a8 | 302 | Your commit message should describe why the change you are making is |
531e2078 | 303 | important. When someone looks at your change in six months or six |
04c692a8 | 304 | years, your intent should be clear. |
7cd58830 | 305 | |
04c692a8 | 306 | If you're deprecating a feature with the intent of later simplifying |
531e2078 | 307 | another bit of code, say so. If you're fixing a performance problem or |
04c692a8 DR |
308 | adding a new feature to support some other bit of the core, mention |
309 | that. | |
7cd58830 | 310 | |
04c692a8 | 311 | =item * What |
7cd58830 | 312 | |
04c692a8 DR |
313 | Your commit message should describe what part of the Perl core you're |
314 | changing and what you expect your patch to do. | |
7cd58830 | 315 | |
04c692a8 | 316 | =item * How |
7cd58830 | 317 | |
04c692a8 DR |
318 | While it's not necessary for documentation changes, new tests or |
319 | trivial patches, it's often worth explaining how your change works. | |
320 | Even if it's clear to you today, it may not be clear to a porter next | |
321 | month or next year. | |
d7889f52 | 322 | |
04c692a8 | 323 | =back |
d7889f52 | 324 | |
04c692a8 | 325 | A commit message isn't intended to take the place of comments in your |
531e2078 | 326 | code. Commit messages should describe the change you made, while code |
04c692a8 | 327 | comments should describe the current state of the code. |
d7889f52 | 328 | |
04c692a8 | 329 | If you've just implemented a new feature, complete with doc, tests and |
531e2078 | 330 | well-commented code, a brief commit message will often suffice. If, |
04c692a8 DR |
331 | however, you've just changed a single character deep in the parser or |
332 | lexer, you might need to write a small novel to ensure that future | |
333 | readers understand what you did and why you did it. | |
d7889f52 | 334 | |
04c692a8 | 335 | =head3 Comments, Comments, Comments |
d7889f52 | 336 | |
a44b8c28 S |
337 | Be sure to adequately comment your code. While commenting every line |
338 | is unnecessary, anything that takes advantage of side effects of | |
04c692a8 DR |
339 | operators, that creates changes that will be felt outside of the |
340 | function being patched, or that others may find confusing should be | |
a44b8c28 S |
341 | documented. If you are going to err, it is better to err on the side |
342 | of adding too many comments than too few. | |
d7889f52 | 343 | |
04c692a8 DR |
344 | The best comments explain I<why> the code does what it does, not I<what |
345 | it does>. | |
d7889f52 | 346 | |
04c692a8 | 347 | =head3 Style |
d7889f52 | 348 | |
04c692a8 DR |
349 | In general, please follow the particular style of the code you are |
350 | patching. | |
d7889f52 | 351 | |
04c692a8 DR |
352 | In particular, follow these general guidelines for patching Perl |
353 | sources: | |
cce04beb | 354 | |
04c692a8 | 355 | =over 4 |
d7889f52 JH |
356 | |
357 | =item * | |
358 | ||
0529658c AL |
359 | 4-wide indents for code, 2-wide indents for nested CPP C<#define>s, |
360 | with 8-wide tabstops. | |
d7889f52 JH |
361 | |
362 | =item * | |
363 | ||
0529658c AL |
364 | Use spaces for indentation, not tab characters. |
365 | ||
366 | The codebase is a mixture of tabs and spaces for indentation, and we | |
367 | are moving to spaces only. Converting lines you're patching from 8-wide | |
368 | tabs to spaces will help this migration. | |
ee9468a2 | 369 | |
cce04beb | 370 | =item * |
ee9468a2 | 371 | |
04c692a8 | 372 | Try hard not to exceed 79-columns |
bc028b6b | 373 | |
ee9468a2 RGS |
374 | =item * |
375 | ||
04c692a8 | 376 | ANSI C prototypes |
d7889f52 JH |
377 | |
378 | =item * | |
379 | ||
04c692a8 | 380 | Uncuddled elses and "K&R" style for indenting control constructs |
0bec6c03 | 381 | |
04c692a8 | 382 | =item * |
d7889f52 | 383 | |
04c692a8 | 384 | No C++ style (//) comments |
d7889f52 JH |
385 | |
386 | =item * | |
387 | ||
04c692a8 | 388 | Mark places that need to be revisited with XXX (and revisit often!) |
27565cb6 JH |
389 | |
390 | =item * | |
391 | ||
04c692a8 DR |
392 | Opening brace lines up with "if" when conditional spans multiple lines; |
393 | should be at end-of-line otherwise | |
27565cb6 | 394 | |
04c692a8 | 395 | =item * |
27565cb6 | 396 | |
15c526cb | 397 | In function definitions, name starts in column 0 (return value-type is on |
04c692a8 | 398 | previous line) |
27565cb6 | 399 | |
04c692a8 | 400 | =item * |
27565cb6 | 401 | |
04c692a8 DR |
402 | Single space after keywords that are followed by parens, no space |
403 | between function name and following paren | |
606fd33d | 404 | |
27565cb6 JH |
405 | =item * |
406 | ||
04c692a8 DR |
407 | Avoid assignments in conditionals, but if they're unavoidable, use |
408 | extra paren, e.g. "if (a && (b = c)) ..." | |
27565cb6 JH |
409 | |
410 | =item * | |
411 | ||
04c692a8 | 412 | "return foo;" rather than "return(foo);" |
27565cb6 JH |
413 | |
414 | =item * | |
415 | ||
04c692a8 | 416 | "if (!foo) ..." rather than "if (foo == FALSE) ..." etc. |
606fd33d | 417 | |
a8bd0d47 KW |
418 | =item * |
419 | ||
420 | Do not declare variables using "register". It may be counterproductive | |
421 | with modern compilers, and is deprecated in C++, under which the Perl | |
422 | source is regularly compiled. | |
423 | ||
5b48d9bb KW |
424 | =item * |
425 | ||
426 | In-line functions that are in headers that are accessible to XS code | |
427 | need to be able to compile without warnings with commonly used extra | |
428 | compilation flags, such as gcc's C<-Wswitch-default> which warns | |
429 | whenever a switch statement does not have a "default" case. The use of | |
a44b8c28 S |
430 | these extra flags is to catch potential problems in legal C code, and |
431 | is often used by Perl aggregators, such as Linux distributors. | |
5b48d9bb | 432 | |
606fd33d | 433 | =back |
27565cb6 | 434 | |
04c692a8 | 435 | =head3 Test suite |
d7889f52 | 436 | |
a8d15a22 | 437 | If your patch changes code (rather than just changing documentation), |
04c692a8 | 438 | you should also include one or more test cases which illustrate the bug |
531e2078 | 439 | you're fixing or validate the new functionality you're adding. In |
04c692a8 DR |
440 | general, you should update an existing test file rather than create a |
441 | new one. | |
2bbc8d55 | 442 | |
04c692a8 DR |
443 | Your test suite additions should generally follow these guidelines |
444 | (courtesy of Gurusamy Sarathy <gsar@activestate.com>): | |
2bbc8d55 | 445 | |
04c692a8 | 446 | =over 4 |
0bec6c03 | 447 | |
04c692a8 | 448 | =item * |
0bec6c03 | 449 | |
531e2078 | 450 | Know what you're testing. Read the docs, and the source. |
ee9468a2 RGS |
451 | |
452 | =item * | |
453 | ||
04c692a8 | 454 | Tend to fail, not succeed. |
0bec6c03 | 455 | |
04c692a8 | 456 | =item * |
0bec6c03 | 457 | |
04c692a8 | 458 | Interpret results strictly. |
27565cb6 | 459 | |
04c692a8 | 460 | =item * |
27565cb6 | 461 | |
04c692a8 | 462 | Use unrelated features (this will flush out bizarre interactions). |
27565cb6 | 463 | |
04c692a8 | 464 | =item * |
27565cb6 | 465 | |
04c692a8 | 466 | Use non-standard idioms (otherwise you are not testing TIMTOWTDI). |
27565cb6 | 467 | |
04c692a8 | 468 | =item * |
d7889f52 | 469 | |
04c692a8 DR |
470 | Avoid using hardcoded test numbers whenever possible (the EXPECTED/GOT |
471 | found in t/op/tie.t is much more maintainable, and gives better failure | |
472 | reports). | |
d7889f52 | 473 | |
04c692a8 | 474 | =item * |
d7889f52 | 475 | |
04c692a8 | 476 | Give meaningful error messages when a test fails. |
d7889f52 | 477 | |
04c692a8 | 478 | =item * |
d7889f52 | 479 | |
531e2078 | 480 | Avoid using qx// and system() unless you are testing for them. If you |
04c692a8 | 481 | do use them, make sure that you cover _all_ perl platforms. |
d7889f52 | 482 | |
04c692a8 | 483 | =item * |
0bec6c03 | 484 | |
04c692a8 | 485 | Unlink any temporary files you create. |
63796a85 | 486 | |
04c692a8 | 487 | =item * |
0bec6c03 | 488 | |
04c692a8 | 489 | Promote unforeseen warnings to errors with $SIG{__WARN__}. |
0bec6c03 | 490 | |
04c692a8 | 491 | =item * |
0bec6c03 | 492 | |
04c692a8 DR |
493 | Be sure to use the libraries and modules shipped with the version being |
494 | tested, not those that were already installed. | |
d7889f52 | 495 | |
04c692a8 | 496 | =item * |
d7889f52 | 497 | |
04c692a8 | 498 | Add comments to the code explaining what you are testing for. |
d7889f52 | 499 | |
04c692a8 | 500 | =item * |
d7889f52 | 501 | |
531e2078 | 502 | Make updating the '1..42' string unnecessary. Or make sure that you |
04c692a8 | 503 | update it. |
d7889f52 | 504 | |
04c692a8 | 505 | =item * |
d7889f52 | 506 | |
04c692a8 | 507 | Test _all_ behaviors of a given operator, library, or function. |
d7889f52 | 508 | |
04c692a8 | 509 | Test all optional arguments. |
d7889f52 | 510 | |
04c692a8 | 511 | Test return values in various contexts (boolean, scalar, list, lvalue). |
d7889f52 | 512 | |
04c692a8 | 513 | Use both global and lexical variables. |
d7889f52 | 514 | |
04c692a8 | 515 | Don't forget the exceptional, pathological cases. |
0bec6c03 | 516 | |
cce04beb | 517 | =back |
0bec6c03 | 518 | |
04c692a8 | 519 | =head2 Patching a core module |
ee9468a2 | 520 | |
04c692a8 DR |
521 | This works just like patching anything else, with one extra |
522 | consideration. | |
63796a85 | 523 | |
a8d15a22 | 524 | Modules in the F<cpan/> directory of the source tree are maintained |
531e2078 | 525 | outside of the Perl core. When the author updates the module, the |
24b68a05 DG |
526 | updates are simply copied into the core. See that module's |
527 | documentation or its listing on L<http://search.cpan.org/> for more | |
528 | information on reporting bugs and submitting patches. | |
529 | ||
530 | In most cases, patches to modules in F<cpan/> should be sent upstream | |
9e6670f3 DR |
531 | and should not be applied to the Perl core individually. If a patch to |
532 | a file in F<cpan/> absolutely cannot wait for the fix to be made | |
7e5887a1 DG |
533 | upstream, released to CPAN and copied to blead, you must add (or |
534 | update) a C<CUSTOMIZED> entry in the F<"Porting/Maintainers.pl"> file | |
535 | to flag that a local modification has been made. See | |
536 | F<"Porting/Maintainers.pl"> for more details. | |
63796a85 | 537 | |
04c692a8 DR |
538 | In contrast, modules in the F<dist/> directory are maintained in the |
539 | core. | |
63796a85 | 540 | |
04c692a8 | 541 | =head2 Updating perldelta |
63796a85 | 542 | |
04c692a8 DR |
543 | For changes significant enough to warrant a F<pod/perldelta.pod> entry, |
544 | the porters will greatly appreciate it if you submit a delta entry | |
a44b8c28 S |
545 | along with your actual change. Significant changes include, but are |
546 | not limited to: | |
63796a85 | 547 | |
04c692a8 | 548 | =over 4 |
63796a85 | 549 | |
04c692a8 | 550 | =item * |
63796a85 | 551 | |
04c692a8 | 552 | Adding, deprecating, or removing core features |
ee9468a2 | 553 | |
04c692a8 | 554 | =item * |
ee9468a2 | 555 | |
04c692a8 | 556 | Adding, deprecating, removing, or upgrading core or dual-life modules |
ee9468a2 | 557 | |
04c692a8 | 558 | =item * |
ee9468a2 | 559 | |
04c692a8 | 560 | Adding new core tests |
ee9468a2 | 561 | |
04c692a8 | 562 | =item * |
ee9468a2 | 563 | |
04c692a8 | 564 | Fixing security issues and user-visible bugs in the core |
cce04beb | 565 | |
04c692a8 | 566 | =item * |
ad7244db | 567 | |
04c692a8 | 568 | Changes that might break existing code, either on the perl or C level |
ad7244db JH |
569 | |
570 | =item * | |
571 | ||
04c692a8 | 572 | Significant performance improvements |
ad7244db JH |
573 | |
574 | =item * | |
575 | ||
04c692a8 DR |
576 | Adding, removing, or significantly changing documentation in the |
577 | F<pod/> directory | |
ad7244db | 578 | |
cce04beb | 579 | =item * |
ad7244db | 580 | |
04c692a8 | 581 | Important platform-specific changes |
d7889f52 | 582 | |
cce04beb DG |
583 | =back |
584 | ||
04c692a8 | 585 | Please make sure you add the perldelta entry to the right section |
531e2078 | 586 | within F<pod/perldelta.pod>. More information on how to write good |
04c692a8 DR |
587 | perldelta entries is available in the C<Style> section of |
588 | F<Porting/how_to_write_a_perldelta.pod>. | |
d7889f52 | 589 | |
04c692a8 | 590 | =head2 What makes for a good patch? |
d7889f52 | 591 | |
531e2078 | 592 | New features and extensions to the language can be contentious. There |
04c692a8 DR |
593 | is no specific set of criteria which determine what features get added, |
594 | but here are some questions to consider when developing a patch: | |
d7889f52 | 595 | |
04c692a8 | 596 | =head3 Does the concept match the general goals of Perl? |
d7889f52 | 597 | |
04c692a8 | 598 | Our goals include, but are not limited to: |
d7889f52 | 599 | |
04c692a8 | 600 | =over 4 |
d7889f52 | 601 | |
04c692a8 | 602 | =item 1. |
d7889f52 | 603 | |
04c692a8 | 604 | Keep it fast, simple, and useful. |
cce04beb | 605 | |
04c692a8 | 606 | =item 2. |
cce04beb | 607 | |
04c692a8 | 608 | Keep features/concepts as orthogonal as possible. |
902b9dbf | 609 | |
04c692a8 | 610 | =item 3. |
902b9dbf | 611 | |
04c692a8 | 612 | No arbitrary limits (platforms, data sizes, cultures). |
a958818a | 613 | |
04c692a8 | 614 | =item 4. |
ac036724 | 615 | |
04c692a8 | 616 | Keep it open and exciting to use/patch/advocate Perl everywhere. |
a958818a | 617 | |
04c692a8 | 618 | =item 5. |
a958818a | 619 | |
04c692a8 | 620 | Either assimilate new technologies, or build bridges to them. |
a958818a | 621 | |
04c692a8 | 622 | =back |
a958818a | 623 | |
04c692a8 | 624 | =head3 Where is the implementation? |
a958818a | 625 | |
531e2078 | 626 | All the talk in the world is useless without an implementation. In |
04c692a8 | 627 | almost every case, the person or people who argue for a new feature |
531e2078 | 628 | will be expected to be the ones who implement it. Porters capable of |
04c692a8 DR |
629 | coding new features have their own agendas, and are not available to |
630 | implement your (possibly good) idea. | |
a1b65709 | 631 | |
04c692a8 | 632 | =head3 Backwards compatibility |
37c0adeb | 633 | |
531e2078 | 634 | It's a cardinal sin to break existing Perl programs. New warnings can |
04c692a8 | 635 | be contentious--some say that a program that emits warnings is not |
531e2078 | 636 | broken, while others say it is. Adding keywords has the potential to |
04c692a8 DR |
637 | break programs, changing the meaning of existing token sequences or |
638 | functions might break programs. | |
f50e5b73 | 639 | |
04c692a8 DR |
640 | The Perl 5 core includes mechanisms to help porters make backwards |
641 | incompatible changes more compatible such as the L<feature> and | |
531e2078 | 642 | L<deprecate> modules. Please use them when appropriate. |
902b9dbf | 643 | |
04c692a8 | 644 | =head3 Could it be a module instead? |
902b9dbf | 645 | |
04c692a8 | 646 | Perl 5 has extension mechanisms, modules and XS, specifically to avoid |
531e2078 | 647 | the need to keep changing the Perl interpreter. You can write modules |
04c692a8 DR |
648 | that export functions, you can give those functions prototypes so they |
649 | can be called like built-in functions, you can even write XS code to | |
650 | mess with the runtime data structures of the Perl interpreter if you | |
651 | want to implement really complicated things. | |
902b9dbf | 652 | |
04c692a8 DR |
653 | Whenever possible, new features should be prototyped in a CPAN module |
654 | before they will be considered for the core. | |
902b9dbf | 655 | |
04c692a8 | 656 | =head3 Is the feature generic enough? |
902b9dbf | 657 | |
04c692a8 DR |
658 | Is this something that only the submitter wants added to the language, |
659 | or is it broadly useful? Sometimes, instead of adding a feature with a | |
660 | tight focus, the porters might decide to wait until someone implements | |
661 | the more generalized feature. | |
902b9dbf | 662 | |
04c692a8 | 663 | =head3 Does it potentially introduce new bugs? |
902b9dbf | 664 | |
04c692a8 DR |
665 | Radical rewrites of large chunks of the Perl interpreter have the |
666 | potential to introduce new bugs. | |
902b9dbf | 667 | |
04c692a8 | 668 | =head3 How big is it? |
902b9dbf | 669 | |
531e2078 | 670 | The smaller and more localized the change, the better. Similarly, a |
04c692a8 | 671 | series of small patches is greatly preferred over a single large patch. |
902b9dbf | 672 | |
04c692a8 | 673 | =head3 Does it preclude other desirable features? |
902b9dbf | 674 | |
04c692a8 | 675 | A patch is likely to be rejected if it closes off future avenues of |
531e2078 | 676 | development. For instance, a patch that placed a true and final |
04c692a8 DR |
677 | interpretation on prototypes is likely to be rejected because there are |
678 | still options for the future of prototypes that haven't been addressed. | |
902b9dbf | 679 | |
04c692a8 | 680 | =head3 Is the implementation robust? |
902b9dbf | 681 | |
04c692a8 | 682 | Good patches (tight code, complete, correct) stand more chance of going |
531e2078 | 683 | in. Sloppy or incorrect patches might be placed on the back burner |
04c692a8 DR |
684 | until the pumpking has time to fix, or might be discarded altogether |
685 | without further notice. | |
902b9dbf | 686 | |
04c692a8 | 687 | =head3 Is the implementation generic enough to be portable? |
902b9dbf | 688 | |
531e2078 | 689 | The worst patches make use of system-specific features. It's highly |
04c692a8 DR |
690 | unlikely that non-portable additions to the Perl language will be |
691 | accepted. | |
902b9dbf | 692 | |
04c692a8 | 693 | =head3 Is the implementation tested? |
902b9dbf | 694 | |
04c692a8 DR |
695 | Patches which change behaviour (fixing bugs or introducing new |
696 | features) must include regression tests to verify that everything works | |
697 | as expected. | |
902b9dbf | 698 | |
04c692a8 DR |
699 | Without tests provided by the original author, how can anyone else |
700 | changing perl in the future be sure that they haven't unwittingly | |
701 | broken the behaviour the patch implements? And without tests, how can | |
702 | the patch's author be confident that his/her hard work put into the | |
703 | patch won't be accidentally thrown away by someone in the future? | |
902b9dbf | 704 | |
04c692a8 | 705 | =head3 Is there enough documentation? |
902b9dbf | 706 | |
04c692a8 | 707 | Patches without documentation are probably ill-thought out or |
531e2078 | 708 | incomplete. No features can be added or changed without documentation, |
04c692a8 DR |
709 | so submitting a patch for the appropriate pod docs as well as the |
710 | source code is important. | |
902b9dbf | 711 | |
04c692a8 | 712 | =head3 Is there another way to do it? |
902b9dbf | 713 | |
04c692a8 | 714 | Larry said "Although the Perl Slogan is I<There's More Than One Way to |
531e2078 | 715 | Do It>, I hesitate to make 10 ways to do something". This is a tricky |
04c692a8 DR |
716 | heuristic to navigate, though--one man's essential addition is another |
717 | man's pointless cruft. | |
902b9dbf | 718 | |
04c692a8 | 719 | =head3 Does it create too much work? |
902b9dbf | 720 | |
04c692a8 DR |
721 | Work for the pumpking, work for Perl programmers, work for module |
722 | authors, ... Perl is supposed to be easy. | |
902b9dbf | 723 | |
04c692a8 | 724 | =head3 Patches speak louder than words |
902b9dbf | 725 | |
531e2078 | 726 | Working code is always preferred to pie-in-the-sky ideas. A patch to |
04c692a8 DR |
727 | add a feature stands a much higher chance of making it to the language |
728 | than does a random feature request, no matter how fervently argued the | |
a44b8c28 S |
729 | request might be. This ties into "Will it be useful?", as the fact |
730 | that someone took the time to make the patch demonstrates a strong | |
731 | desire for the feature. | |
c406981e | 732 | |
04c692a8 | 733 | =head1 TESTING |
c406981e | 734 | |
04c692a8 DR |
735 | The core uses the same testing style as the rest of Perl, a simple |
736 | "ok/not ok" run through Test::Harness, but there are a few special | |
737 | considerations. | |
c406981e | 738 | |
531e2078 | 739 | There are three ways to write a test in the core: L<Test::More>, |
a44b8c28 S |
740 | F<t/test.pl> and ad hoc C<print $test ? "ok 42\n" : "not ok 42\n">. |
741 | The decision of which to use depends on what part of the test suite | |
742 | you're working on. This is a measure to prevent a high-level failure | |
743 | (such as Config.pm breaking) from causing basic functionality tests to | |
744 | fail. | |
c406981e | 745 | |
04c692a8 DR |
746 | The F<t/test.pl> library provides some of the features of |
747 | L<Test::More>, but avoids loading most modules and uses as few core | |
748 | features as possible. | |
902b9dbf | 749 | |
9e6670f3 DR |
750 | If you write your own test, use the L<Test Anything |
751 | Protocol|http://testanything.org>. | |
902b9dbf MLF |
752 | |
753 | =over 4 | |
754 | ||
bb52f720 | 755 | =item * F<t/base>, F<t/comp> and F<t/opbasic> |
902b9dbf | 756 | |
15c526cb | 757 | Since we don't know if C<require> works, or even subroutines, use ad hoc |
531e2078 | 758 | tests for these three. Step carefully to avoid using the feature being |
a44b8c28 S |
759 | tested. Tests in F<t/opbasic>, for instance, have been placed there |
760 | rather than in F<t/op> because they test functionality which | |
761 | F<t/test.pl> presumes has already been demonstrated to work. | |
902b9dbf | 762 | |
a8d15a22 | 763 | =item * F<t/cmd>, F<t/run>, F<t/io> and F<t/op> |
902b9dbf | 764 | |
04c692a8 DR |
765 | Now that basic require() and subroutines are tested, you can use the |
766 | F<t/test.pl> library. | |
902b9dbf | 767 | |
a8d15a22 | 768 | You can also use certain libraries like Config conditionally, but be |
04c692a8 | 769 | sure to skip the test gracefully if it's not there. |
902b9dbf | 770 | |
04c692a8 | 771 | =item * Everything else |
902b9dbf | 772 | |
04c692a8 | 773 | Now that the core of Perl is tested, L<Test::More> can and should be |
531e2078 | 774 | used. You can also use the full suite of core modules in the tests. |
902b9dbf MLF |
775 | |
776 | =back | |
777 | ||
a8d15a22 | 778 | When you say "make test", Perl uses the F<t/TEST> program to run the |
a44b8c28 S |
779 | test suite (except under Win32 where it uses F<t/harness> instead). |
780 | All tests are run from the F<t/> directory, B<not> the directory which | |
781 | contains the test. This causes some problems with the tests in | |
782 | F<lib/>, so here's some opportunity for some patching. | |
902b9dbf | 783 | |
531e2078 | 784 | You must be triply conscious of cross-platform concerns. This usually |
eb9df707 KW |
785 | boils down to using L<File::Spec>, avoiding things like C<fork()> |
786 | and C<system()> unless absolutely necessary, and not assuming that a | |
787 | given character has a particular ordinal value (code point) or that its | |
788 | UTF-8 representation is composed of particular bytes. | |
789 | ||
790 | There are several functions available to specify characters and code | |
791 | points portably in tests. The always-preloaded functions | |
792 | C<utf8::unicode_to_native()> and its inverse | |
793 | C<utf8::native_to_unicode()> take code points and translate | |
794 | appropriately. The file F<t/charset_tools.pl> has several functions | |
795 | that can be useful. It has versions of the previous two functions | |
796 | that take strings as inputs -- not single numeric code points: | |
797 | C<uni_to_native()> and C<native_to_uni()>. If you must look at the | |
798 | individual bytes comprising a UTF-8 encoded string, | |
799 | C<byte_utf8a_to_utf8n()> takes as input a string of those bytes encoded | |
800 | for an ASCII platform, and returns the equivalent string in the native | |
801 | platform. For example, C<byte_utf8a_to_utf8n("\xC2\xA0")> returns the | |
802 | byte sequence on the current platform that form the UTF-8 for C<U+00A0>, | |
803 | since C<"\xC2\xA0"> are the UTF-8 bytes on an ASCII platform for that | |
804 | code point. This function returns C<"\xC2\xA0"> on an ASCII platform, and | |
805 | C<"\x80\x41"> on an EBCDIC 1047 one. | |
806 | ||
15c526cb KW |
807 | But easiest is, if the character is specifiable as a literal, like |
808 | C<"A"> or C<"%">, to use that; if not so specificable, you can use use | |
809 | C<\N{}> , if the side effects aren't troublesome. Simply specify all | |
810 | your characters in hex, using C<\N{U+ZZ}> instead of C<\xZZ>. C<\N{}> | |
811 | is the Unicode name, and so it | |
eb9df707 KW |
812 | always gives you the Unicode character. C<\N{U+41}> is the character |
813 | whose Unicode code point is C<0x41>, hence is C<'A'> on all platforms. | |
814 | The side effects are: | |
815 | ||
816 | =over 4 | |
817 | ||
3f9568ff | 818 | =item * |
eb9df707 KW |
819 | |
820 | These select Unicode rules. That means that in double-quotish strings, | |
821 | the string is always converted to UTF-8 to force a Unicode | |
822 | interpretation (you can C<utf8::downgrade()> afterwards to convert back | |
823 | to non-UTF8, if possible). In regular expression patterns, the | |
824 | conversion isn't done, but if the character set modifier would | |
825 | otherwise be C</d>, it is changed to C</u>. | |
826 | ||
3f9568ff | 827 | =item * |
eb9df707 KW |
828 | |
829 | If you use the form C<\N{I<character name>}>, the L<charnames> module | |
830 | gets automatically loaded. This may not be suitable for the test level | |
831 | you are doing. | |
832 | ||
833 | =back | |
7a834142 | 834 | |
15c526cb KW |
835 | If you are testing locales (see L<perllocale>), there are helper |
836 | functions in F<t/loc_tools.pl> to enable you to see what locales there | |
837 | are on the current platform. | |
838 | ||
04c692a8 | 839 | =head2 Special C<make test> targets |
07aa3531 | 840 | |
04c692a8 | 841 | There are various special make targets that can be used to test Perl |
531e2078 FC |
842 | slightly differently than the standard "test" target. Not all them are |
843 | expected to give a 100% success rate. Many of them have several | |
04c692a8 DR |
844 | aliases, and many of them are not available on certain operating |
845 | systems. | |
07aa3531 | 846 | |
04c692a8 | 847 | =over 4 |
d44161bf | 848 | |
04c692a8 | 849 | =item * test_porting |
7a834142 | 850 | |
04c692a8 DR |
851 | This runs some basic sanity tests on the source tree and helps catch |
852 | basic errors before you submit a patch. | |
7a834142 | 853 | |
04c692a8 | 854 | =item * minitest |
51a35ef1 | 855 | |
04c692a8 DR |
856 | Run F<miniperl> on F<t/base>, F<t/comp>, F<t/cmd>, F<t/run>, F<t/io>, |
857 | F<t/op>, F<t/uni> and F<t/mro> tests. | |
51a35ef1 | 858 | |
499cea6b | 859 | =item * test.valgrind check.valgrind |
51a35ef1 | 860 | |
04c692a8 | 861 | (Only in Linux) Run all the tests using the memory leak + naughty |
531e2078 | 862 | memory access tool "valgrind". The log files will be named |
04c692a8 | 863 | F<testname.valgrind>. |
83f0ef60 | 864 | |
04c692a8 | 865 | =item * test_harness |
83f0ef60 | 866 | |
04c692a8 | 867 | Run the test suite with the F<t/harness> controlling program, instead |
531e2078 | 868 | of F<t/TEST>. F<t/harness> is more sophisticated, and uses the |
04c692a8 | 869 | L<Test::Harness> module, thus using this test target supposes that perl |
531e2078 | 870 | mostly works. The main advantage for our purposes is that it prints a |
a44b8c28 S |
871 | detailed summary of failed tests at the end. Also, unlike F<t/TEST>, |
872 | it doesn't redirect stderr to stdout. | |
83f0ef60 | 873 | |
04c692a8 DR |
874 | Note that under Win32 F<t/harness> is always used instead of F<t/TEST>, |
875 | so there is no special "test_harness" target. | |
83f0ef60 | 876 | |
04c692a8 DR |
877 | Under Win32's "test" target you may use the TEST_SWITCHES and |
878 | TEST_FILES environment variables to control the behaviour of | |
531e2078 | 879 | F<t/harness>. This means you can say |
83f0ef60 | 880 | |
04c692a8 DR |
881 | nmake test TEST_FILES="op/*.t" |
882 | nmake test TEST_SWITCHES="-torture" TEST_FILES="op/*.t" | |
83f0ef60 | 883 | |
78087e0a R |
884 | =item * test-notty test_notty |
885 | ||
886 | Sets PERL_SKIP_TTY_TEST to true before running normal test. | |
887 | ||
83f0ef60 JH |
888 | =back |
889 | ||
04c692a8 | 890 | =head2 Parallel tests |
83f0ef60 | 891 | |
04c692a8 | 892 | The core distribution can now run its regression tests in parallel on |
531e2078 | 893 | Unix-like platforms. Instead of running C<make test>, set C<TEST_JOBS> |
04c692a8 | 894 | in your environment to the number of tests to run in parallel, and run |
531e2078 | 895 | C<make test_harness>. On a Bourne-like shell, this can be done as |
07aa3531 | 896 | |
04c692a8 | 897 | TEST_JOBS=3 make test_harness # Run 3 tests in parallel |
07aa3531 | 898 | |
04c692a8 DR |
899 | An environment variable is used, rather than parallel make itself, |
900 | because L<TAP::Harness> needs to be able to schedule individual | |
901 | non-conflicting test scripts itself, and there is no standard interface | |
902 | to C<make> utilities to interact with their job schedulers. | |
51a35ef1 | 903 | |
9e6670f3 | 904 | Note that currently some test scripts may fail when run in parallel |
cb0ee57a | 905 | (most notably F<dist/IO/t/io_dir.t>). If necessary, run just the |
a44b8c28 | 906 | failing scripts again sequentially and see if the failures go away. |
51a35ef1 | 907 | |
04c692a8 | 908 | =head2 Running tests by hand |
51a35ef1 | 909 | |
9e6670f3 DR |
910 | You can run part of the test suite by hand by using one of the |
911 | following commands from the F<t/> directory: | |
51a35ef1 | 912 | |
04c692a8 | 913 | ./perl -I../lib TEST list-of-.t-files |
51a35ef1 | 914 | |
04c692a8 | 915 | or |
51a35ef1 | 916 | |
04c692a8 | 917 | ./perl -I../lib harness list-of-.t-files |
51a35ef1 | 918 | |
a8d15a22 | 919 | (If you don't specify test scripts, the whole test suite will be run.) |
51a35ef1 | 920 | |
04c692a8 | 921 | =head2 Using F<t/harness> for testing |
51a35ef1 | 922 | |
9e6670f3 | 923 | If you use C<harness> for testing, you have several command line |
531e2078 | 924 | options available to you. The arguments are as follows, and are in the |
9e6670f3 | 925 | order that they must appear if used together. |
51a35ef1 | 926 | |
04c692a8 DR |
927 | harness -v -torture -re=pattern LIST OF FILES TO TEST |
928 | harness -v -torture -re LIST OF PATTERNS TO MATCH | |
07aa3531 | 929 | |
a8d15a22 | 930 | If C<LIST OF FILES TO TEST> is omitted, the file list is obtained from |
531e2078 | 931 | the manifest. The file list may include shell wildcards which will be |
04c692a8 | 932 | expanded out. |
07aa3531 | 933 | |
04c692a8 | 934 | =over 4 |
4ae3d70a | 935 | |
04c692a8 | 936 | =item * -v |
4ae3d70a | 937 | |
04c692a8 DR |
938 | Run the tests under verbose mode so you can see what tests were run, |
939 | and debug output. | |
51a35ef1 | 940 | |
04c692a8 | 941 | =item * -torture |
4ae3d70a | 942 | |
04c692a8 | 943 | Run the torture tests as well as the normal set. |
4ae3d70a | 944 | |
04c692a8 | 945 | =item * -re=PATTERN |
6c41479b | 946 | |
a44b8c28 S |
947 | Filter the file list so that all the test files run match PATTERN. |
948 | Note that this form is distinct from the B<-re LIST OF PATTERNS> form | |
949 | below in that it allows the file list to be provided as well. | |
6c41479b | 950 | |
04c692a8 | 951 | =item * -re LIST OF PATTERNS |
6c41479b | 952 | |
04c692a8 | 953 | Filter the file list so that all the test files run match |
531e2078 | 954 | /(LIST|OF|PATTERNS)/. Note that with this form the patterns are joined |
04c692a8 DR |
955 | by '|' and you cannot supply a list of files, instead the test files |
956 | are obtained from the MANIFEST. | |
6c41479b | 957 | |
04c692a8 | 958 | =back |
6c41479b | 959 | |
04c692a8 | 960 | You can run an individual test by a command similar to |
6c41479b | 961 | |
a8d15a22 | 962 | ./perl -I../lib path/to/foo.t |
6c41479b | 963 | |
04c692a8 DR |
964 | except that the harnesses set up some environment variables that may |
965 | affect the execution of the test: | |
6c41479b JH |
966 | |
967 | =over 4 | |
968 | ||
04c692a8 | 969 | =item * PERL_CORE=1 |
6c41479b | 970 | |
a8d15a22 | 971 | indicates that we're running this test as part of the perl core test |
531e2078 | 972 | suite. This is useful for modules that have a dual life on CPAN. |
6c41479b | 973 | |
04c692a8 | 974 | =item * PERL_DESTRUCT_LEVEL=2 |
6c41479b | 975 | |
04c692a8 | 976 | is set to 2 if it isn't set already (see |
a8d15a22 | 977 | L<perlhacktips/PERL_DESTRUCT_LEVEL>). |
6c41479b | 978 | |
04c692a8 | 979 | =item * PERL |
6c41479b | 980 | |
04c692a8 DR |
981 | (used only by F<t/TEST>) if set, overrides the path to the perl |
982 | executable that should be used to run the tests (the default being | |
983 | F<./perl>). | |
6c41479b | 984 | |
04c692a8 | 985 | =item * PERL_SKIP_TTY_TEST |
6c41479b | 986 | |
a44b8c28 S |
987 | if set, tells to skip the tests that need a terminal. It's actually |
988 | set automatically by the Makefile, but can also be forced artificially | |
989 | by running 'make test_notty'. | |
6c41479b | 990 | |
04c692a8 | 991 | =back |
6c41479b | 992 | |
04c692a8 | 993 | =head3 Other environment variables that may influence tests |
6c41479b | 994 | |
04c692a8 | 995 | =over 4 |
6c41479b | 996 | |
04c692a8 | 997 | =item * PERL_TEST_Net_Ping |
6c41479b | 998 | |
04c692a8 | 999 | Setting this variable runs all the Net::Ping modules tests, otherwise |
531e2078 | 1000 | some tests that interact with the outside world are skipped. See |
04c692a8 | 1001 | L<perl58delta>. |
6c41479b | 1002 | |
04c692a8 | 1003 | =item * PERL_TEST_NOVREXX |
cce04beb | 1004 | |
04c692a8 | 1005 | Setting this variable skips the vrexx.t tests for OS2::REXX. |
cce04beb | 1006 | |
04c692a8 | 1007 | =item * PERL_TEST_NUMCONVERTS |
cce04beb | 1008 | |
04c692a8 | 1009 | This sets a variable in op/numconvert.t. |
cce04beb | 1010 | |
ff5db609 TC |
1011 | =item * PERL_TEST_MEMORY |
1012 | ||
1013 | Setting this variable includes the tests in F<t/bigmem/>. This should | |
a44b8c28 S |
1014 | be set to the number of gigabytes of memory available for testing, eg. |
1015 | C<PERL_TEST_MEMORY=4> indicates that tests that require 4GiB of | |
ff5db609 TC |
1016 | available memory can be run safely. |
1017 | ||
04c692a8 | 1018 | =back |
cce04beb | 1019 | |
04c692a8 DR |
1020 | See also the documentation for the Test and Test::Harness modules, for |
1021 | more environment variables that affect testing. | |
cce04beb | 1022 | |
9e7973fa DM |
1023 | =head2 Performance testing |
1024 | ||
1025 | The file F<t/perf/benchmarks> contains snippets of perl code which are | |
1026 | intended to be benchmarked across a range of perls by the | |
1027 | F<Porting/bench.pl> tool. If you fix or enhance a performance issue, you | |
1028 | may want to add a representative code sample to the file, then run | |
1029 | F<bench.pl> against the previous and current perls to see what difference | |
1030 | it has made, and whether anything else has slowed down as a consequence. | |
1031 | ||
1032 | The file F<t/perf/opcount.t> is designed to test whether a particular | |
1033 | code snippet has been compiled into an optree containing specified | |
1034 | numbers of particular op types. This is good for testing whether | |
1035 | optimisations which alter ops, such as converting an C<aelem> op into an | |
1036 | C<aelemfast> op, are really doing that. | |
1037 | ||
1038 | The files F<t/perf/speed.t> and F<t/re/speed.t> are designed to test | |
1039 | things that run thousands of times slower if a particular optimisation | |
1040 | is broken (for example, the utf8 length cache on long utf8 strings). | |
1041 | Add a test that will take a fraction of a second normally, and minutes | |
1042 | otherwise, causing the test file to time out on failure. | |
1043 | ||
04c692a8 | 1044 | =head1 MORE READING FOR GUTS HACKERS |
cce04beb | 1045 | |
04c692a8 | 1046 | To hack on the Perl guts, you'll need to read the following things: |
cce04beb | 1047 | |
04c692a8 | 1048 | =over 4 |
cce04beb | 1049 | |
04c692a8 | 1050 | =item * L<perlsource> |
b8ddf6b3 | 1051 | |
531e2078 | 1052 | An overview of the Perl source tree. This will help you find the files |
04c692a8 | 1053 | you're looking for. |
b8ddf6b3 | 1054 | |
04c692a8 | 1055 | =item * L<perlinterp> |
b8ddf6b3 | 1056 | |
04c692a8 DR |
1057 | An overview of the Perl interpreter source code and some details on how |
1058 | Perl does what it does. | |
b8ddf6b3 | 1059 | |
04c692a8 | 1060 | =item * L<perlhacktut> |
b8ddf6b3 | 1061 | |
04c692a8 | 1062 | This document walks through the creation of a small patch to Perl's C |
531e2078 | 1063 | code. If you're just getting started with Perl core hacking, this will |
04c692a8 | 1064 | help you understand how it works. |
b8ddf6b3 | 1065 | |
04c692a8 | 1066 | =item * L<perlhacktips> |
b8ddf6b3 | 1067 | |
531e2078 | 1068 | More details on hacking the Perl core. This document focuses on lower |
04c692a8 DR |
1069 | level details such as how to write tests, compilation issues, |
1070 | portability, debugging, etc. | |
b8ddf6b3 | 1071 | |
04c692a8 | 1072 | If you plan on doing serious C hacking, make sure to read this. |
b8ddf6b3 | 1073 | |
04c692a8 | 1074 | =item * L<perlguts> |
b8ddf6b3 | 1075 | |
04c692a8 | 1076 | This is of paramount importance, since it's the documentation of what |
531e2078 | 1077 | goes where in the Perl source. Read it over a couple of times and it |
04c692a8 DR |
1078 | might start to make sense - don't worry if it doesn't yet, because the |
1079 | best way to study it is to read it in conjunction with poking at Perl | |
1080 | source, and we'll do that later on. | |
b8ddf6b3 | 1081 | |
04c692a8 DR |
1082 | Gisle Aas's "illustrated perlguts", also known as I<illguts>, has very |
1083 | helpful pictures: | |
9965345d | 1084 | |
04c692a8 | 1085 | L<http://search.cpan.org/dist/illguts/> |
9965345d | 1086 | |
04c692a8 | 1087 | =item * L<perlxstut> and L<perlxs> |
f1fac472 | 1088 | |
04c692a8 DR |
1089 | A working knowledge of XSUB programming is incredibly useful for core |
1090 | hacking; XSUBs use techniques drawn from the PP code, the portion of | |
531e2078 | 1091 | the guts that actually executes a Perl program. It's a lot gentler to |
04c692a8 DR |
1092 | learn those techniques from simple examples and explanation than from |
1093 | the core itself. | |
f1fac472 | 1094 | |
04c692a8 | 1095 | =item * L<perlapi> |
f1fac472 | 1096 | |
04c692a8 DR |
1097 | The documentation for the Perl API explains what some of the internal |
1098 | functions do, as well as the many macros used in the source. | |
f1fac472 | 1099 | |
04c692a8 | 1100 | =item * F<Porting/pumpkin.pod> |
f1fac472 | 1101 | |
04c692a8 DR |
1102 | This is a collection of words of wisdom for a Perl porter; some of it |
1103 | is only useful to the pumpkin holder, but most of it applies to anyone | |
1104 | wanting to go about Perl development. | |
f1fac472 | 1105 | |
04c692a8 | 1106 | =back |
f1fac472 | 1107 | |
04c692a8 | 1108 | =head1 CPAN TESTERS AND PERL SMOKERS |
f1fac472 | 1109 | |
04c692a8 DR |
1110 | The CPAN testers ( http://testers.cpan.org/ ) are a group of volunteers |
1111 | who test CPAN modules on a variety of platforms. | |
b8ddf6b3 | 1112 | |
a8d15a22 | 1113 | Perl Smokers ( http://www.nntp.perl.org/group/perl.daily-build/ and |
04c692a8 DR |
1114 | http://www.nntp.perl.org/group/perl.daily-build.reports/ ) |
1115 | automatically test Perl source releases on platforms with various | |
1116 | configurations. | |
f1fac472 | 1117 | |
531e2078 | 1118 | Both efforts welcome volunteers. In order to get involved in smoke |
04c692a8 | 1119 | testing of the perl itself visit |
531e2078 | 1120 | L<http://search.cpan.org/dist/Test-Smoke/>. In order to start smoke |
04c692a8 DR |
1121 | testing CPAN modules visit |
1122 | L<http://search.cpan.org/dist/CPANPLUS-YACSmoke/> or | |
1123 | L<http://search.cpan.org/dist/minismokebox/> or | |
1124 | L<http://search.cpan.org/dist/CPAN-Reporter/>. | |
f1fac472 | 1125 | |
04c692a8 | 1126 | =head1 WHAT NEXT? |
a422fd2d | 1127 | |
04c692a8 DR |
1128 | If you've read all the documentation in the document and the ones |
1129 | listed above, you're more than ready to hack on Perl. | |
a422fd2d | 1130 | |
04c692a8 | 1131 | Here's some more recommendations |
a422fd2d | 1132 | |
04c692a8 | 1133 | =over 4 |
a422fd2d SC |
1134 | |
1135 | =item * | |
1136 | ||
1137 | Subscribe to perl5-porters, follow the patches and try and understand | |
1138 | them; don't be afraid to ask if there's a portion you're not clear on - | |
1139 | who knows, you may unearth a bug in the patch... | |
1140 | ||
1141 | =item * | |
1142 | ||
04c692a8 | 1143 | Do read the README associated with your operating system, e.g. |
531e2078 | 1144 | README.aix on the IBM AIX OS. Don't hesitate to supply patches to that |
04c692a8 | 1145 | README if you find anything missing or changed over a new OS release. |
a1f349fd MB |
1146 | |
1147 | =item * | |
1148 | ||
a422fd2d | 1149 | Find an area of Perl that seems interesting to you, and see if you can |
a44b8c28 S |
1150 | work out how it works. Scan through the source, and step over it in |
1151 | the debugger. Play, poke, investigate, fiddle! You'll probably get to | |
04c692a8 DR |
1152 | understand not just your chosen area but a much wider range of |
1153 | F<perl>'s activity as well, and probably sooner than you'd think. | |
a422fd2d SC |
1154 | |
1155 | =back | |
1156 | ||
04c692a8 | 1157 | =head2 "The Road goes ever on and on, down from the door where it began." |
a422fd2d | 1158 | |
04c692a8 | 1159 | If you can do these things, you've started on the long road to Perl |
531e2078 | 1160 | porting. Thanks for wanting to help make Perl better - and happy |
04c692a8 | 1161 | hacking! |
a422fd2d | 1162 | |
4ac71550 TC |
1163 | =head2 Metaphoric Quotations |
1164 | ||
1165 | If you recognized the quote about the Road above, you're in luck. | |
1166 | ||
04c692a8 | 1167 | Most software projects begin each file with a literal description of |
531e2078 | 1168 | each file's purpose. Perl instead begins each with a literary allusion |
04c692a8 | 1169 | to that file's purpose. |
4ac71550 | 1170 | |
04c692a8 | 1171 | Like chapters in many books, all top-level Perl source files (along |
9e6670f3 DR |
1172 | with a few others here and there) begin with an epigrammatic |
1173 | inscription that alludes, indirectly and metaphorically, to the | |
1174 | material you're about to read. | |
4ac71550 | 1175 | |
a8d15a22 | 1176 | Quotations are taken from writings of J.R.R. Tolkien pertaining to his |
531e2078 | 1177 | Legendarium, almost always from I<The Lord of the Rings>. Chapters and |
4ac71550 TC |
1178 | page numbers are given using the following editions: |
1179 | ||
1180 | =over 4 | |
1181 | ||
04c692a8 | 1182 | =item * |
4ac71550 | 1183 | |
531e2078 | 1184 | I<The Hobbit>, by J.R.R. Tolkien. The hardcover, 70th-anniversary |
04c692a8 DR |
1185 | edition of 2007 was used, published in the UK by Harper Collins |
1186 | Publishers and in the US by the Houghton Mifflin Company. | |
4ac71550 TC |
1187 | |
1188 | =item * | |
1189 | ||
531e2078 | 1190 | I<The Lord of the Rings>, by J.R.R. Tolkien. The hardcover, |
04c692a8 DR |
1191 | 50th-anniversary edition of 2004 was used, published in the UK by |
1192 | Harper Collins Publishers and in the US by the Houghton Mifflin | |
1193 | Company. | |
4ac71550 TC |
1194 | |
1195 | =item * | |
1196 | ||
04c692a8 DR |
1197 | I<The Lays of Beleriand>, by J.R.R. Tolkien and published posthumously |
1198 | by his son and literary executor, C.J.R. Tolkien, being the 3rd of the | |
531e2078 | 1199 | 12 volumes in Christopher's mammoth I<History of Middle Earth>. Page |
04c692a8 DR |
1200 | numbers derive from the hardcover edition, first published in 1983 by |
1201 | George Allen & Unwin; no page numbers changed for the special 3-volume | |
1202 | omnibus edition of 2002 or the various trade-paper editions, all again | |
1203 | now by Harper Collins or Houghton Mifflin. | |
4ac71550 TC |
1204 | |
1205 | =back | |
1206 | ||
04c692a8 DR |
1207 | Other JRRT books fair game for quotes would thus include I<The |
1208 | Adventures of Tom Bombadil>, I<The Silmarillion>, I<Unfinished Tales>, | |
1209 | and I<The Tale of the Children of Hurin>, all but the first | |
531e2078 | 1210 | posthumously assembled by CJRT. But I<The Lord of the Rings> itself is |
04c692a8 DR |
1211 | perfectly fine and probably best to quote from, provided you can find a |
1212 | suitable quote there. | |
4ac71550 | 1213 | |
04c692a8 DR |
1214 | So if you were to supply a new, complete, top-level source file to add |
1215 | to Perl, you should conform to this peculiar practice by yourself | |
1216 | selecting an appropriate quotation from Tolkien, retaining the original | |
1217 | spelling and punctuation and using the same format the rest of the | |
531e2078 | 1218 | quotes are in. Indirect and oblique is just fine; remember, it's a |
04c692a8 | 1219 | metaphor, so being meta is, after all, what it's for. |
4ac71550 | 1220 | |
e8cd7eae GS |
1221 | =head1 AUTHOR |
1222 | ||
04c692a8 DR |
1223 | This document was originally written by Nathan Torkington, and is |
1224 | maintained by the perl5-porters mailing list. |