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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 |
617d9ec4 | 14 | about the Perl 5 Porters email list, the Perl repository, the Perl |
04c692a8 DR |
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 | |
47ef154c | 30 | % git clone https://github.com/Perl/perl5.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 | ||
617d9ec4 DB |
39 | =item * Create a branch for your change |
40 | ||
41 | Create a branch based on blead to commit your change to, which will | |
42 | later be used to send it to the Perl issue tracker. | |
43 | ||
44 | % git checkout -b mychange | |
45 | ||
04c692a8 | 46 | =item * Make your change |
e018f8be | 47 | |
eb9df707 KW |
48 | Hack, hack, hack. Keep in mind that Perl runs on many different |
49 | platforms, with different operating systems that have different | |
50 | capabilities, different filesystem organizations, and even different | |
51 | character sets. L<perlhacktips> gives advice on this. | |
7205a85d | 52 | |
04c692a8 | 53 | =item * Test your change |
e018f8be | 54 | |
04c692a8 | 55 | You can run all the tests with the following commands: |
b26492ee | 56 | |
04c692a8 DR |
57 | % ./Configure -des -Dusedevel |
58 | % make test | |
7205a85d | 59 | |
04c692a8 | 60 | Keep hacking until the tests pass. |
b26492ee | 61 | |
04c692a8 | 62 | =item * Commit your change |
e018f8be | 63 | |
b6538e4f | 64 | Committing your work will save the change I<on your local system>: |
7205a85d | 65 | |
04c692a8 | 66 | % git commit -a -m 'Commit message goes here' |
e018f8be | 67 | |
04c692a8 | 68 | Make sure the commit message describes your change in a single |
531e2078 | 69 | sentence. For example, "Fixed spelling errors in perlhack.pod". |
e018f8be | 70 | |
617d9ec4 | 71 | =item * Send your change to the Perl issue tracker |
7a834142 | 72 | |
617d9ec4 | 73 | The next step is to submit your patch to the Perl core ticket system. |
7a834142 | 74 | |
617d9ec4 DB |
75 | Create a GitHub fork of the perl5 repository and add it as a remote, |
76 | if you haven't already, as described in the GitHub documentation at | |
77 | L<https://help.github.com/en/articles/working-with-forks>. | |
e018f8be | 78 | |
617d9ec4 | 79 | % git remote add fork git@github.com:MyUser/perl5.git |
e018f8be | 80 | |
b998bd1a | 81 | For more information, see L<"Connecting to GitHub with SSH"|https://docs.github.com/en/free-pro-team@latest/github/authenticating-to-github/connecting-to-github-with-ssh>. |
82 | ||
83 | If you'd rather use an HTTPS URL for your C<git push> see L<"Cloning with | |
84 | HTTPS URLs"|https://docs.github.com/en/free-pro-team@latest/github/using-git/which-remote-url-should-i-use#cloning-with-https-urls>. | |
85 | ||
86 | % git remote add fork https://github.com/MyUser/perl5.git | |
87 | ||
617d9ec4 | 88 | Then, push your new branch to your fork. |
e018f8be | 89 | |
617d9ec4 | 90 | % git push -u fork mychange |
2d1c9392 | 91 | |
617d9ec4 DB |
92 | Finally, create a Pull Request on GitHub from your branch to blead as |
93 | described in the GitHub documentation at | |
94 | L<https://help.github.com/en/articles/creating-a-pull-request-from-a-fork>. | |
2d1c9392 | 95 | |
04c692a8 | 96 | =item * Thank you |
e018f8be | 97 | |
04c692a8 DR |
98 | The porters appreciate the time you spent helping to make Perl better. |
99 | Thank you! | |
e018f8be | 100 | |
bb288857 S |
101 | =item * Acknowledgement |
102 | ||
103 | All contributors are credited (by name and email address) in the | |
6cb72a3d S |
104 | AUTHORS file, which is part of the perl distribution, as well as the |
105 | Git commit history. | |
bb288857 S |
106 | |
107 | If you don’t want to be included in the AUTHORS file, just let us | |
108 | know. Otherwise we will take your submission of a patch as permission | |
109 | to credit you in the AUTHORS file. | |
110 | ||
e99cf3f0 S |
111 | =item * Next time |
112 | ||
113 | The next time you wish to make a patch, you need to start from the | |
30454452 | 114 | latest perl in a pristine state. Check you don't have any local changes |
e99cf3f0 S |
115 | or added files in your perl check-out which you wish to keep, then run |
116 | these commands: | |
117 | ||
617d9ec4 | 118 | % git checkout blead |
e99cf3f0 S |
119 | % git pull |
120 | % git reset --hard origin/blead | |
121 | % git clean -dxf | |
122 | ||
cce04beb | 123 | =back |
e018f8be | 124 | |
04c692a8 | 125 | =head1 BUG REPORTING |
cc0710ff | 126 | |
8166b4e0 DB |
127 | If you want to report a bug in Perl, or browse existing Perl bugs and |
128 | patches, use the GitHub issue tracker at | |
129 | L<https://github.com/perl/perl5/issues>. | |
244d9cb7 | 130 | |
04c692a8 | 131 | Please check the archive of the perl5-porters list (see below) and/or |
531e2078 | 132 | the bug tracking system before submitting a bug report. Often, you'll |
04c692a8 | 133 | find that the bug has been reported already. |
244d9cb7 | 134 | |
04c692a8 | 135 | You can log in to the bug tracking system and comment on existing bug |
531e2078 FC |
136 | reports. If you have additional information regarding an existing bug, |
137 | please add it. This will help the porters fix the bug. | |
7205a85d | 138 | |
04c692a8 | 139 | =head1 PERL 5 PORTERS |
7205a85d | 140 | |
04c692a8 | 141 | The perl5-porters (p5p) mailing list is where the Perl standard |
531e2078 | 142 | distribution is maintained and developed. The people who maintain Perl |
9e6670f3 DR |
143 | are also referred to as the "Perl 5 Porters", "p5p" or just the |
144 | "porters". | |
a75f557c | 145 | |
04c692a8 | 146 | A searchable archive of the list is available at |
71c89d21 MM |
147 | L<https://markmail.org/search/?q=perl5-porters>. There is also an archive at |
148 | L<https://archive.develooper.com/perl5-porters@perl.org/>. | |
7205a85d | 149 | |
04c692a8 | 150 | =head2 perl-changes mailing list |
7205a85d | 151 | |
04c692a8 DR |
152 | The perl5-changes mailing list receives a copy of each patch that gets |
153 | submitted to the maintenance and development branches of the perl | |
fdee78a1 | 154 | repository. See L<https://lists.perl.org/list/perl5-changes.html> for |
04c692a8 | 155 | subscription and archive information. |
244d9cb7 | 156 | |
37bf3a91 DR |
157 | =head2 #p5p on IRC |
158 | ||
159 | Many porters are also active on the L<irc://irc.perl.org/#p5p> channel. | |
160 | Feel free to join the channel and ask questions about hacking on the | |
161 | Perl core. | |
162 | ||
04c692a8 | 163 | =head1 GETTING THE PERL SOURCE |
244d9cb7 | 164 | |
04c692a8 | 165 | All of Perl's source code is kept centrally in a Git repository at |
47ef154c | 166 | I<github.com>. The repository contains many Perl revisions |
a44b8c28 | 167 | from Perl 1 onwards and all the revisions from Perforce, the previous |
04c692a8 | 168 | version control system. |
244d9cb7 | 169 | |
04c692a8 DR |
170 | For much more detail on using git with the Perl repository, please see |
171 | L<perlgit>. | |
244d9cb7 | 172 | |
04c692a8 | 173 | =head2 Read access via Git |
244d9cb7 | 174 | |
531e2078 | 175 | You will need a copy of Git for your computer. You can fetch a copy of |
04c692a8 | 176 | the repository using the git protocol: |
244d9cb7 | 177 | |
a85e04e2 | 178 | % git clone git@github.com:Perl/perl5.git perl |
244d9cb7 | 179 | |
04c692a8 DR |
180 | This clones the repository and makes a local copy in the F<perl> |
181 | directory. | |
7205a85d | 182 | |
04c692a8 | 183 | If you cannot use the git protocol for firewall reasons, you can also |
47ef154c | 184 | clone via http: |
7205a85d | 185 | |
47ef154c | 186 | % git clone https://github.com/Perl/perl5.git perl |
7205a85d | 187 | |
04c692a8 | 188 | =head2 Read access via the web |
7205a85d | 189 | |
531e2078 | 190 | You may access the repository over the web. This allows you to browse |
47ef154c | 191 | the tree, see recent commits, subscribe to repository notifications, |
531e2078 | 192 | search for particular commits and more. You may access it at |
47ef154c | 193 | L<https://github.com/Perl/perl5>. |
7205a85d | 194 | |
04c692a8 | 195 | =head2 Write access via git |
7205a85d | 196 | |
04c692a8 DR |
197 | If you have a commit bit, please see L<perlgit> for more details on |
198 | using git. | |
7205a85d | 199 | |
04c692a8 | 200 | =head1 PATCHING PERL |
7205a85d | 201 | |
04c692a8 | 202 | If you're planning to do more extensive work than a single small fix, |
531e2078 | 203 | we encourage you to read the documentation below. This will help you |
04c692a8 DR |
204 | focus your work and make your patches easier to incorporate into the |
205 | Perl source. | |
244d9cb7 | 206 | |
04c692a8 | 207 | =head2 Submitting patches |
244d9cb7 | 208 | |
617d9ec4 DB |
209 | If you have a small patch to submit, please submit it via the GitHub |
210 | Pull Request workflow. You may also send patches to the p5p list. | |
244d9cb7 | 211 | |
617d9ec4 | 212 | Patches are reviewed and discussed on GitHub or the p5p list. Simple, |
04c692a8 DR |
213 | uncontroversial patches will usually be applied without any discussion. |
214 | When the patch is applied, the ticket will be updated and you will | |
617d9ec4 | 215 | receive email. |
244d9cb7 | 216 | |
617d9ec4 | 217 | In other cases, the patch will need more work or discussion. |
04c692a8 | 218 | You are encouraged to participate in the discussion and advocate for |
531e2078 | 219 | your patch. Sometimes your patch may get lost in the shuffle. It's |
04c692a8 | 220 | appropriate to send a reminder email to p5p if no action has been taken |
531e2078 | 221 | in a month. Please remember that the Perl 5 developers are all |
04c692a8 | 222 | volunteers, and be polite. |
244d9cb7 | 223 | |
04c692a8 | 224 | Changes are always applied directly to the main development branch, |
a44b8c28 | 225 | called "blead". Some patches may be backported to a maintenance |
30454452 | 226 | branch. If you think your patch is appropriate for the maintenance |
839a0e5a | 227 | branch (see L<perlpolicy/MAINTENANCE BRANCHES>), please explain why |
d0bba22e | 228 | when you submit it. |
244d9cb7 | 229 | |
04c692a8 | 230 | =head2 Getting your patch accepted |
244d9cb7 | 231 | |
84c2f6fd DR |
232 | If you are submitting a code patch there are several things that you |
233 | can do to help the Perl 5 Porters accept your patch. | |
244d9cb7 | 234 | |
a126fb62 DR |
235 | =head3 Patch style |
236 | ||
617d9ec4 DB |
237 | Using the GitHub Pull Request workflow, your patch will automatically |
238 | be available in a suitable format. If you wish to submit a patch to | |
239 | the p5p list for review, make sure to create it appropriately. | |
240 | ||
a126fb62 | 241 | If you used git to check out the Perl source, then using C<git |
531e2078 | 242 | format-patch> will produce a patch in a style suitable for Perl. The |
a126fb62 | 243 | C<format-patch> command produces one patch file for each commit you |
a44b8c28 S |
244 | made. If you prefer to send a single patch for all commits, you can |
245 | use C<git diff>. | |
a126fb62 | 246 | |
9d440a18 | 247 | % git checkout blead |
a126fb62 DR |
248 | % git pull |
249 | % git diff blead my-branch-name | |
250 | ||
251 | This produces a patch based on the difference between blead and your | |
531e2078 | 252 | current branch. It's important to make sure that blead is up to date |
a126fb62 DR |
253 | before producing the diff, that's why we call C<git pull> first. |
254 | ||
531e2078 | 255 | We strongly recommend that you use git if possible. It will make your |
a126fb62 DR |
256 | life easier, and ours as well. |
257 | ||
258 | However, if you're not using git, you can still produce a suitable | |
531e2078 FC |
259 | patch. You'll need a pristine copy of the Perl source to diff against. |
260 | The porters prefer unified diffs. Using GNU C<diff>, you can produce a | |
a126fb62 DR |
261 | diff like this: |
262 | ||
263 | % diff -Npurd perl.pristine perl.mine | |
264 | ||
265 | Make sure that you C<make realclean> in your copy of Perl to remove any | |
266 | build artifacts, or you may get a confusing result. | |
267 | ||
04c692a8 | 268 | =head3 Commit message |
244d9cb7 | 269 | |
04c692a8 | 270 | As you craft each patch you intend to submit to the Perl core, it's |
531e2078 | 271 | important to write a good commit message. This is especially important |
04c692a8 | 272 | if your submission will consist of a series of commits. |
244d9cb7 | 273 | |
04c692a8 | 274 | The first line of the commit message should be a short description |
531e2078 | 275 | without a period. It should be no longer than the subject line of an |
a8d15a22 | 276 | email, 50 characters being a good rule of thumb. |
f7e1e956 | 277 | |
a8d15a22 | 278 | A lot of Git tools (Gitweb, GitHub, git log --pretty=oneline, ...) will |
04c692a8 DR |
279 | only display the first line (cut off at 50 characters) when presenting |
280 | commit summaries. | |
7cd58830 | 281 | |
04c692a8 DR |
282 | The commit message should include a description of the problem that the |
283 | patch corrects or new functionality that the patch adds. | |
7cd58830 | 284 | |
04c692a8 DR |
285 | As a general rule of thumb, your commit message should help a |
286 | programmer who knows the Perl core quickly understand what you were | |
287 | trying to do, how you were trying to do it, and why the change matters | |
288 | to Perl. | |
7cd58830 | 289 | |
04c692a8 | 290 | =over 4 |
7cd58830 | 291 | |
04c692a8 | 292 | =item * Why |
7cd58830 | 293 | |
04c692a8 | 294 | Your commit message should describe why the change you are making is |
531e2078 | 295 | important. When someone looks at your change in six months or six |
04c692a8 | 296 | years, your intent should be clear. |
7cd58830 | 297 | |
04c692a8 | 298 | If you're deprecating a feature with the intent of later simplifying |
531e2078 | 299 | another bit of code, say so. If you're fixing a performance problem or |
04c692a8 DR |
300 | adding a new feature to support some other bit of the core, mention |
301 | that. | |
7cd58830 | 302 | |
04c692a8 | 303 | =item * What |
7cd58830 | 304 | |
04c692a8 DR |
305 | Your commit message should describe what part of the Perl core you're |
306 | changing and what you expect your patch to do. | |
7cd58830 | 307 | |
04c692a8 | 308 | =item * How |
7cd58830 | 309 | |
04c692a8 DR |
310 | While it's not necessary for documentation changes, new tests or |
311 | trivial patches, it's often worth explaining how your change works. | |
312 | Even if it's clear to you today, it may not be clear to a porter next | |
313 | month or next year. | |
d7889f52 | 314 | |
04c692a8 | 315 | =back |
d7889f52 | 316 | |
04c692a8 | 317 | A commit message isn't intended to take the place of comments in your |
531e2078 | 318 | code. Commit messages should describe the change you made, while code |
04c692a8 | 319 | comments should describe the current state of the code. |
d7889f52 | 320 | |
04c692a8 | 321 | If you've just implemented a new feature, complete with doc, tests and |
531e2078 | 322 | well-commented code, a brief commit message will often suffice. If, |
04c692a8 DR |
323 | however, you've just changed a single character deep in the parser or |
324 | lexer, you might need to write a small novel to ensure that future | |
325 | readers understand what you did and why you did it. | |
d7889f52 | 326 | |
04c692a8 | 327 | =head3 Comments, Comments, Comments |
d7889f52 | 328 | |
a44b8c28 S |
329 | Be sure to adequately comment your code. While commenting every line |
330 | is unnecessary, anything that takes advantage of side effects of | |
04c692a8 DR |
331 | operators, that creates changes that will be felt outside of the |
332 | function being patched, or that others may find confusing should be | |
a44b8c28 S |
333 | documented. If you are going to err, it is better to err on the side |
334 | of adding too many comments than too few. | |
d7889f52 | 335 | |
04c692a8 DR |
336 | The best comments explain I<why> the code does what it does, not I<what |
337 | it does>. | |
d7889f52 | 338 | |
04c692a8 | 339 | =head3 Style |
d7889f52 | 340 | |
04c692a8 DR |
341 | In general, please follow the particular style of the code you are |
342 | patching. | |
d7889f52 | 343 | |
04c692a8 DR |
344 | In particular, follow these general guidelines for patching Perl |
345 | sources: | |
cce04beb | 346 | |
04c692a8 | 347 | =over 4 |
d7889f52 JH |
348 | |
349 | =item * | |
350 | ||
0529658c AL |
351 | 4-wide indents for code, 2-wide indents for nested CPP C<#define>s, |
352 | with 8-wide tabstops. | |
d7889f52 JH |
353 | |
354 | =item * | |
355 | ||
0529658c AL |
356 | Use spaces for indentation, not tab characters. |
357 | ||
358 | The codebase is a mixture of tabs and spaces for indentation, and we | |
359 | are moving to spaces only. Converting lines you're patching from 8-wide | |
360 | tabs to spaces will help this migration. | |
ee9468a2 | 361 | |
cce04beb | 362 | =item * |
ee9468a2 | 363 | |
04c692a8 | 364 | Try hard not to exceed 79-columns |
bc028b6b | 365 | |
ee9468a2 RGS |
366 | =item * |
367 | ||
04c692a8 | 368 | ANSI C prototypes |
d7889f52 JH |
369 | |
370 | =item * | |
371 | ||
04c692a8 | 372 | Uncuddled elses and "K&R" style for indenting control constructs |
0bec6c03 | 373 | |
04c692a8 | 374 | =item * |
d7889f52 | 375 | |
04c692a8 | 376 | No C++ style (//) comments |
d7889f52 JH |
377 | |
378 | =item * | |
379 | ||
04c692a8 | 380 | Mark places that need to be revisited with XXX (and revisit often!) |
27565cb6 JH |
381 | |
382 | =item * | |
383 | ||
04c692a8 DR |
384 | Opening brace lines up with "if" when conditional spans multiple lines; |
385 | should be at end-of-line otherwise | |
27565cb6 | 386 | |
04c692a8 | 387 | =item * |
27565cb6 | 388 | |
15c526cb | 389 | In function definitions, name starts in column 0 (return value-type is on |
04c692a8 | 390 | previous line) |
27565cb6 | 391 | |
04c692a8 | 392 | =item * |
27565cb6 | 393 | |
04c692a8 DR |
394 | Single space after keywords that are followed by parens, no space |
395 | between function name and following paren | |
606fd33d | 396 | |
27565cb6 JH |
397 | =item * |
398 | ||
04c692a8 DR |
399 | Avoid assignments in conditionals, but if they're unavoidable, use |
400 | extra paren, e.g. "if (a && (b = c)) ..." | |
27565cb6 JH |
401 | |
402 | =item * | |
403 | ||
04c692a8 | 404 | "return foo;" rather than "return(foo);" |
27565cb6 JH |
405 | |
406 | =item * | |
407 | ||
04c692a8 | 408 | "if (!foo) ..." rather than "if (foo == FALSE) ..." etc. |
606fd33d | 409 | |
a8bd0d47 KW |
410 | =item * |
411 | ||
412 | Do not declare variables using "register". It may be counterproductive | |
413 | with modern compilers, and is deprecated in C++, under which the Perl | |
414 | source is regularly compiled. | |
415 | ||
5b48d9bb KW |
416 | =item * |
417 | ||
418 | In-line functions that are in headers that are accessible to XS code | |
419 | need to be able to compile without warnings with commonly used extra | |
420 | compilation flags, such as gcc's C<-Wswitch-default> which warns | |
421 | whenever a switch statement does not have a "default" case. The use of | |
a44b8c28 S |
422 | these extra flags is to catch potential problems in legal C code, and |
423 | is often used by Perl aggregators, such as Linux distributors. | |
5b48d9bb | 424 | |
606fd33d | 425 | =back |
27565cb6 | 426 | |
04c692a8 | 427 | =head3 Test suite |
d7889f52 | 428 | |
a8d15a22 | 429 | If your patch changes code (rather than just changing documentation), |
04c692a8 | 430 | you should also include one or more test cases which illustrate the bug |
531e2078 | 431 | you're fixing or validate the new functionality you're adding. In |
04c692a8 DR |
432 | general, you should update an existing test file rather than create a |
433 | new one. | |
2bbc8d55 | 434 | |
04c692a8 DR |
435 | Your test suite additions should generally follow these guidelines |
436 | (courtesy of Gurusamy Sarathy <gsar@activestate.com>): | |
2bbc8d55 | 437 | |
04c692a8 | 438 | =over 4 |
0bec6c03 | 439 | |
04c692a8 | 440 | =item * |
0bec6c03 | 441 | |
531e2078 | 442 | Know what you're testing. Read the docs, and the source. |
ee9468a2 RGS |
443 | |
444 | =item * | |
445 | ||
04c692a8 | 446 | Tend to fail, not succeed. |
0bec6c03 | 447 | |
04c692a8 | 448 | =item * |
0bec6c03 | 449 | |
04c692a8 | 450 | Interpret results strictly. |
27565cb6 | 451 | |
04c692a8 | 452 | =item * |
27565cb6 | 453 | |
04c692a8 | 454 | Use unrelated features (this will flush out bizarre interactions). |
27565cb6 | 455 | |
04c692a8 | 456 | =item * |
27565cb6 | 457 | |
04c692a8 | 458 | Use non-standard idioms (otherwise you are not testing TIMTOWTDI). |
27565cb6 | 459 | |
04c692a8 | 460 | =item * |
d7889f52 | 461 | |
04c692a8 DR |
462 | Avoid using hardcoded test numbers whenever possible (the EXPECTED/GOT |
463 | found in t/op/tie.t is much more maintainable, and gives better failure | |
464 | reports). | |
d7889f52 | 465 | |
04c692a8 | 466 | =item * |
d7889f52 | 467 | |
04c692a8 | 468 | Give meaningful error messages when a test fails. |
d7889f52 | 469 | |
04c692a8 | 470 | =item * |
d7889f52 | 471 | |
531e2078 | 472 | Avoid using qx// and system() unless you are testing for them. If you |
04c692a8 | 473 | do use them, make sure that you cover _all_ perl platforms. |
d7889f52 | 474 | |
04c692a8 | 475 | =item * |
0bec6c03 | 476 | |
04c692a8 | 477 | Unlink any temporary files you create. |
63796a85 | 478 | |
04c692a8 | 479 | =item * |
0bec6c03 | 480 | |
04c692a8 | 481 | Promote unforeseen warnings to errors with $SIG{__WARN__}. |
0bec6c03 | 482 | |
04c692a8 | 483 | =item * |
0bec6c03 | 484 | |
04c692a8 DR |
485 | Be sure to use the libraries and modules shipped with the version being |
486 | tested, not those that were already installed. | |
d7889f52 | 487 | |
04c692a8 | 488 | =item * |
d7889f52 | 489 | |
04c692a8 | 490 | Add comments to the code explaining what you are testing for. |
d7889f52 | 491 | |
04c692a8 | 492 | =item * |
d7889f52 | 493 | |
531e2078 | 494 | Make updating the '1..42' string unnecessary. Or make sure that you |
04c692a8 | 495 | update it. |
d7889f52 | 496 | |
04c692a8 | 497 | =item * |
d7889f52 | 498 | |
04c692a8 | 499 | Test _all_ behaviors of a given operator, library, or function. |
d7889f52 | 500 | |
04c692a8 | 501 | Test all optional arguments. |
d7889f52 | 502 | |
04c692a8 | 503 | Test return values in various contexts (boolean, scalar, list, lvalue). |
d7889f52 | 504 | |
04c692a8 | 505 | Use both global and lexical variables. |
d7889f52 | 506 | |
04c692a8 | 507 | Don't forget the exceptional, pathological cases. |
0bec6c03 | 508 | |
cce04beb | 509 | =back |
0bec6c03 | 510 | |
04c692a8 | 511 | =head2 Patching a core module |
ee9468a2 | 512 | |
04c692a8 DR |
513 | This works just like patching anything else, with one extra |
514 | consideration. | |
63796a85 | 515 | |
a8d15a22 | 516 | Modules in the F<cpan/> directory of the source tree are maintained |
531e2078 | 517 | outside of the Perl core. When the author updates the module, the |
24b68a05 | 518 | updates are simply copied into the core. See that module's |
5e17962d | 519 | documentation or its listing on L<https://metacpan.org/> for more |
24b68a05 DG |
520 | information on reporting bugs and submitting patches. |
521 | ||
522 | In most cases, patches to modules in F<cpan/> should be sent upstream | |
9e6670f3 DR |
523 | and should not be applied to the Perl core individually. If a patch to |
524 | a file in F<cpan/> absolutely cannot wait for the fix to be made | |
7e5887a1 DG |
525 | upstream, released to CPAN and copied to blead, you must add (or |
526 | update) a C<CUSTOMIZED> entry in the F<"Porting/Maintainers.pl"> file | |
527 | to flag that a local modification has been made. See | |
528 | F<"Porting/Maintainers.pl"> for more details. | |
63796a85 | 529 | |
04c692a8 DR |
530 | In contrast, modules in the F<dist/> directory are maintained in the |
531 | core. | |
63796a85 | 532 | |
04c692a8 | 533 | =head2 Updating perldelta |
63796a85 | 534 | |
04c692a8 DR |
535 | For changes significant enough to warrant a F<pod/perldelta.pod> entry, |
536 | the porters will greatly appreciate it if you submit a delta entry | |
a44b8c28 S |
537 | along with your actual change. Significant changes include, but are |
538 | not limited to: | |
63796a85 | 539 | |
04c692a8 | 540 | =over 4 |
63796a85 | 541 | |
04c692a8 | 542 | =item * |
63796a85 | 543 | |
04c692a8 | 544 | Adding, deprecating, or removing core features |
ee9468a2 | 545 | |
04c692a8 | 546 | =item * |
ee9468a2 | 547 | |
04c692a8 | 548 | Adding, deprecating, removing, or upgrading core or dual-life modules |
ee9468a2 | 549 | |
04c692a8 | 550 | =item * |
ee9468a2 | 551 | |
04c692a8 | 552 | Adding new core tests |
ee9468a2 | 553 | |
04c692a8 | 554 | =item * |
ee9468a2 | 555 | |
04c692a8 | 556 | Fixing security issues and user-visible bugs in the core |
cce04beb | 557 | |
04c692a8 | 558 | =item * |
ad7244db | 559 | |
04c692a8 | 560 | Changes that might break existing code, either on the perl or C level |
ad7244db JH |
561 | |
562 | =item * | |
563 | ||
04c692a8 | 564 | Significant performance improvements |
ad7244db JH |
565 | |
566 | =item * | |
567 | ||
04c692a8 DR |
568 | Adding, removing, or significantly changing documentation in the |
569 | F<pod/> directory | |
ad7244db | 570 | |
cce04beb | 571 | =item * |
ad7244db | 572 | |
04c692a8 | 573 | Important platform-specific changes |
d7889f52 | 574 | |
cce04beb DG |
575 | =back |
576 | ||
04c692a8 | 577 | Please make sure you add the perldelta entry to the right section |
531e2078 | 578 | within F<pod/perldelta.pod>. More information on how to write good |
04c692a8 DR |
579 | perldelta entries is available in the C<Style> section of |
580 | F<Porting/how_to_write_a_perldelta.pod>. | |
d7889f52 | 581 | |
04c692a8 | 582 | =head2 What makes for a good patch? |
d7889f52 | 583 | |
531e2078 | 584 | New features and extensions to the language can be contentious. There |
04c692a8 DR |
585 | is no specific set of criteria which determine what features get added, |
586 | but here are some questions to consider when developing a patch: | |
d7889f52 | 587 | |
04c692a8 | 588 | =head3 Does the concept match the general goals of Perl? |
d7889f52 | 589 | |
04c692a8 | 590 | Our goals include, but are not limited to: |
d7889f52 | 591 | |
04c692a8 | 592 | =over 4 |
d7889f52 | 593 | |
04c692a8 | 594 | =item 1. |
d7889f52 | 595 | |
04c692a8 | 596 | Keep it fast, simple, and useful. |
cce04beb | 597 | |
04c692a8 | 598 | =item 2. |
cce04beb | 599 | |
04c692a8 | 600 | Keep features/concepts as orthogonal as possible. |
902b9dbf | 601 | |
04c692a8 | 602 | =item 3. |
902b9dbf | 603 | |
04c692a8 | 604 | No arbitrary limits (platforms, data sizes, cultures). |
a958818a | 605 | |
04c692a8 | 606 | =item 4. |
ac036724 | 607 | |
04c692a8 | 608 | Keep it open and exciting to use/patch/advocate Perl everywhere. |
a958818a | 609 | |
04c692a8 | 610 | =item 5. |
a958818a | 611 | |
04c692a8 | 612 | Either assimilate new technologies, or build bridges to them. |
a958818a | 613 | |
04c692a8 | 614 | =back |
a958818a | 615 | |
04c692a8 | 616 | =head3 Where is the implementation? |
a958818a | 617 | |
531e2078 | 618 | All the talk in the world is useless without an implementation. In |
04c692a8 | 619 | almost every case, the person or people who argue for a new feature |
531e2078 | 620 | will be expected to be the ones who implement it. Porters capable of |
04c692a8 DR |
621 | coding new features have their own agendas, and are not available to |
622 | implement your (possibly good) idea. | |
a1b65709 | 623 | |
04c692a8 | 624 | =head3 Backwards compatibility |
37c0adeb | 625 | |
531e2078 | 626 | It's a cardinal sin to break existing Perl programs. New warnings can |
04c692a8 | 627 | be contentious--some say that a program that emits warnings is not |
531e2078 | 628 | broken, while others say it is. Adding keywords has the potential to |
04c692a8 DR |
629 | break programs, changing the meaning of existing token sequences or |
630 | functions might break programs. | |
f50e5b73 | 631 | |
04c692a8 DR |
632 | The Perl 5 core includes mechanisms to help porters make backwards |
633 | incompatible changes more compatible such as the L<feature> and | |
531e2078 | 634 | L<deprecate> modules. Please use them when appropriate. |
902b9dbf | 635 | |
04c692a8 | 636 | =head3 Could it be a module instead? |
902b9dbf | 637 | |
04c692a8 | 638 | Perl 5 has extension mechanisms, modules and XS, specifically to avoid |
531e2078 | 639 | the need to keep changing the Perl interpreter. You can write modules |
04c692a8 DR |
640 | that export functions, you can give those functions prototypes so they |
641 | can be called like built-in functions, you can even write XS code to | |
642 | mess with the runtime data structures of the Perl interpreter if you | |
643 | want to implement really complicated things. | |
902b9dbf | 644 | |
04c692a8 DR |
645 | Whenever possible, new features should be prototyped in a CPAN module |
646 | before they will be considered for the core. | |
902b9dbf | 647 | |
04c692a8 | 648 | =head3 Is the feature generic enough? |
902b9dbf | 649 | |
04c692a8 DR |
650 | Is this something that only the submitter wants added to the language, |
651 | or is it broadly useful? Sometimes, instead of adding a feature with a | |
652 | tight focus, the porters might decide to wait until someone implements | |
653 | the more generalized feature. | |
902b9dbf | 654 | |
04c692a8 | 655 | =head3 Does it potentially introduce new bugs? |
902b9dbf | 656 | |
04c692a8 DR |
657 | Radical rewrites of large chunks of the Perl interpreter have the |
658 | potential to introduce new bugs. | |
902b9dbf | 659 | |
04c692a8 | 660 | =head3 How big is it? |
902b9dbf | 661 | |
531e2078 | 662 | The smaller and more localized the change, the better. Similarly, a |
04c692a8 | 663 | series of small patches is greatly preferred over a single large patch. |
902b9dbf | 664 | |
04c692a8 | 665 | =head3 Does it preclude other desirable features? |
902b9dbf | 666 | |
04c692a8 | 667 | A patch is likely to be rejected if it closes off future avenues of |
531e2078 | 668 | development. For instance, a patch that placed a true and final |
04c692a8 DR |
669 | interpretation on prototypes is likely to be rejected because there are |
670 | still options for the future of prototypes that haven't been addressed. | |
902b9dbf | 671 | |
04c692a8 | 672 | =head3 Is the implementation robust? |
902b9dbf | 673 | |
04c692a8 | 674 | Good patches (tight code, complete, correct) stand more chance of going |
531e2078 | 675 | in. Sloppy or incorrect patches might be placed on the back burner |
66c65f79 | 676 | until fixes can be made, or they might be discarded altogether |
04c692a8 | 677 | without further notice. |
902b9dbf | 678 | |
04c692a8 | 679 | =head3 Is the implementation generic enough to be portable? |
902b9dbf | 680 | |
531e2078 | 681 | The worst patches make use of system-specific features. It's highly |
04c692a8 DR |
682 | unlikely that non-portable additions to the Perl language will be |
683 | accepted. | |
902b9dbf | 684 | |
04c692a8 | 685 | =head3 Is the implementation tested? |
902b9dbf | 686 | |
04c692a8 DR |
687 | Patches which change behaviour (fixing bugs or introducing new |
688 | features) must include regression tests to verify that everything works | |
689 | as expected. | |
902b9dbf | 690 | |
04c692a8 DR |
691 | Without tests provided by the original author, how can anyone else |
692 | changing perl in the future be sure that they haven't unwittingly | |
693 | broken the behaviour the patch implements? And without tests, how can | |
694 | the patch's author be confident that his/her hard work put into the | |
695 | patch won't be accidentally thrown away by someone in the future? | |
902b9dbf | 696 | |
04c692a8 | 697 | =head3 Is there enough documentation? |
902b9dbf | 698 | |
04c692a8 | 699 | Patches without documentation are probably ill-thought out or |
531e2078 | 700 | incomplete. No features can be added or changed without documentation, |
04c692a8 DR |
701 | so submitting a patch for the appropriate pod docs as well as the |
702 | source code is important. | |
902b9dbf | 703 | |
04c692a8 | 704 | =head3 Is there another way to do it? |
902b9dbf | 705 | |
04c692a8 | 706 | Larry said "Although the Perl Slogan is I<There's More Than One Way to |
531e2078 | 707 | Do It>, I hesitate to make 10 ways to do something". This is a tricky |
04c692a8 DR |
708 | heuristic to navigate, though--one man's essential addition is another |
709 | man's pointless cruft. | |
902b9dbf | 710 | |
04c692a8 | 711 | =head3 Does it create too much work? |
902b9dbf | 712 | |
66c65f79 | 713 | Work for the committers, work for Perl programmers, work for module |
04c692a8 | 714 | authors, ... Perl is supposed to be easy. |
902b9dbf | 715 | |
04c692a8 | 716 | =head3 Patches speak louder than words |
902b9dbf | 717 | |
531e2078 | 718 | Working code is always preferred to pie-in-the-sky ideas. A patch to |
04c692a8 DR |
719 | add a feature stands a much higher chance of making it to the language |
720 | than does a random feature request, no matter how fervently argued the | |
a44b8c28 S |
721 | request might be. This ties into "Will it be useful?", as the fact |
722 | that someone took the time to make the patch demonstrates a strong | |
723 | desire for the feature. | |
c406981e | 724 | |
04c692a8 | 725 | =head1 TESTING |
c406981e | 726 | |
04c692a8 DR |
727 | The core uses the same testing style as the rest of Perl, a simple |
728 | "ok/not ok" run through Test::Harness, but there are a few special | |
729 | considerations. | |
c406981e | 730 | |
531e2078 | 731 | There are three ways to write a test in the core: L<Test::More>, |
a44b8c28 S |
732 | F<t/test.pl> and ad hoc C<print $test ? "ok 42\n" : "not ok 42\n">. |
733 | The decision of which to use depends on what part of the test suite | |
734 | you're working on. This is a measure to prevent a high-level failure | |
735 | (such as Config.pm breaking) from causing basic functionality tests to | |
736 | fail. | |
c406981e | 737 | |
04c692a8 DR |
738 | The F<t/test.pl> library provides some of the features of |
739 | L<Test::More>, but avoids loading most modules and uses as few core | |
740 | features as possible. | |
902b9dbf | 741 | |
9e6670f3 | 742 | If you write your own test, use the L<Test Anything |
71c89d21 | 743 | Protocol|https://testanything.org>. |
902b9dbf MLF |
744 | |
745 | =over 4 | |
746 | ||
bb52f720 | 747 | =item * F<t/base>, F<t/comp> and F<t/opbasic> |
902b9dbf | 748 | |
15c526cb | 749 | Since we don't know if C<require> works, or even subroutines, use ad hoc |
531e2078 | 750 | tests for these three. Step carefully to avoid using the feature being |
a44b8c28 S |
751 | tested. Tests in F<t/opbasic>, for instance, have been placed there |
752 | rather than in F<t/op> because they test functionality which | |
753 | F<t/test.pl> presumes has already been demonstrated to work. | |
902b9dbf | 754 | |
070720ff | 755 | =item * All other subdirectories of F<t/> |
902b9dbf | 756 | |
04c692a8 DR |
757 | Now that basic require() and subroutines are tested, you can use the |
758 | F<t/test.pl> library. | |
902b9dbf | 759 | |
070720ff | 760 | You can also use certain libraries like L<Config> conditionally, but be |
04c692a8 | 761 | sure to skip the test gracefully if it's not there. |
902b9dbf | 762 | |
070720ff | 763 | =item * Test files not found under F<t/> |
902b9dbf | 764 | |
070720ff JK |
765 | This category includes F<.t> files underneath directories such as F<dist>, |
766 | F<ext> and F<lib>. Since the core of Perl has now been tested, L<Test::More> | |
767 | can and now should be used. You can also use the full suite of core modules | |
768 | in the tests. (As noted in L<"Patching a core module"> above, changes to | |
769 | F<.t> files found under F<cpan/> should be submitted to the upstream | |
770 | maintainers of those modules.) | |
902b9dbf MLF |
771 | |
772 | =back | |
773 | ||
a8d15a22 | 774 | When you say "make test", Perl uses the F<t/TEST> program to run the |
a44b8c28 S |
775 | test suite (except under Win32 where it uses F<t/harness> instead). |
776 | All tests are run from the F<t/> directory, B<not> the directory which | |
777 | contains the test. This causes some problems with the tests in | |
778 | F<lib/>, so here's some opportunity for some patching. | |
902b9dbf | 779 | |
531e2078 | 780 | You must be triply conscious of cross-platform concerns. This usually |
eb9df707 KW |
781 | boils down to using L<File::Spec>, avoiding things like C<fork()> |
782 | and C<system()> unless absolutely necessary, and not assuming that a | |
783 | given character has a particular ordinal value (code point) or that its | |
784 | UTF-8 representation is composed of particular bytes. | |
785 | ||
786 | There are several functions available to specify characters and code | |
787 | points portably in tests. The always-preloaded functions | |
788 | C<utf8::unicode_to_native()> and its inverse | |
789 | C<utf8::native_to_unicode()> take code points and translate | |
790 | appropriately. The file F<t/charset_tools.pl> has several functions | |
791 | that can be useful. It has versions of the previous two functions | |
792 | that take strings as inputs -- not single numeric code points: | |
793 | C<uni_to_native()> and C<native_to_uni()>. If you must look at the | |
794 | individual bytes comprising a UTF-8 encoded string, | |
795 | C<byte_utf8a_to_utf8n()> takes as input a string of those bytes encoded | |
796 | for an ASCII platform, and returns the equivalent string in the native | |
797 | platform. For example, C<byte_utf8a_to_utf8n("\xC2\xA0")> returns the | |
798 | byte sequence on the current platform that form the UTF-8 for C<U+00A0>, | |
799 | since C<"\xC2\xA0"> are the UTF-8 bytes on an ASCII platform for that | |
800 | code point. This function returns C<"\xC2\xA0"> on an ASCII platform, and | |
801 | C<"\x80\x41"> on an EBCDIC 1047 one. | |
802 | ||
15c526cb | 803 | But easiest is, if the character is specifiable as a literal, like |
a3815e44 | 804 | C<"A"> or C<"%">, to use that; if not so specificable, you can use |
15c526cb KW |
805 | C<\N{}> , if the side effects aren't troublesome. Simply specify all |
806 | your characters in hex, using C<\N{U+ZZ}> instead of C<\xZZ>. C<\N{}> | |
807 | is the Unicode name, and so it | |
eb9df707 KW |
808 | always gives you the Unicode character. C<\N{U+41}> is the character |
809 | whose Unicode code point is C<0x41>, hence is C<'A'> on all platforms. | |
810 | The side effects are: | |
811 | ||
812 | =over 4 | |
813 | ||
3f9568ff | 814 | =item * |
eb9df707 KW |
815 | |
816 | These select Unicode rules. That means that in double-quotish strings, | |
817 | the string is always converted to UTF-8 to force a Unicode | |
818 | interpretation (you can C<utf8::downgrade()> afterwards to convert back | |
819 | to non-UTF8, if possible). In regular expression patterns, the | |
820 | conversion isn't done, but if the character set modifier would | |
821 | otherwise be C</d>, it is changed to C</u>. | |
822 | ||
3f9568ff | 823 | =item * |
eb9df707 KW |
824 | |
825 | If you use the form C<\N{I<character name>}>, the L<charnames> module | |
826 | gets automatically loaded. This may not be suitable for the test level | |
827 | you are doing. | |
828 | ||
829 | =back | |
7a834142 | 830 | |
15c526cb KW |
831 | If you are testing locales (see L<perllocale>), there are helper |
832 | functions in F<t/loc_tools.pl> to enable you to see what locales there | |
833 | are on the current platform. | |
834 | ||
04c692a8 | 835 | =head2 Special C<make test> targets |
07aa3531 | 836 | |
04c692a8 | 837 | There are various special make targets that can be used to test Perl |
531e2078 FC |
838 | slightly differently than the standard "test" target. Not all them are |
839 | expected to give a 100% success rate. Many of them have several | |
04c692a8 DR |
840 | aliases, and many of them are not available on certain operating |
841 | systems. | |
07aa3531 | 842 | |
04c692a8 | 843 | =over 4 |
d44161bf | 844 | |
04c692a8 | 845 | =item * test_porting |
7a834142 | 846 | |
04c692a8 DR |
847 | This runs some basic sanity tests on the source tree and helps catch |
848 | basic errors before you submit a patch. | |
7a834142 | 849 | |
04c692a8 | 850 | =item * minitest |
51a35ef1 | 851 | |
04c692a8 DR |
852 | Run F<miniperl> on F<t/base>, F<t/comp>, F<t/cmd>, F<t/run>, F<t/io>, |
853 | F<t/op>, F<t/uni> and F<t/mro> tests. | |
51a35ef1 | 854 | |
f9d2c26d TC |
855 | F<miniperl> is a minimalistic perl built to bootstrap building |
856 | extensions, utilties, documentation etc. It doesn't support dynamic | |
857 | loading and depending on the point in the build process will only have | |
858 | access to a limited set of core modules. F<miniperl> is not intended | |
859 | for day to day use. | |
860 | ||
499cea6b | 861 | =item * test.valgrind check.valgrind |
51a35ef1 | 862 | |
04c692a8 | 863 | (Only in Linux) Run all the tests using the memory leak + naughty |
531e2078 | 864 | memory access tool "valgrind". The log files will be named |
04c692a8 | 865 | F<testname.valgrind>. |
83f0ef60 | 866 | |
04c692a8 | 867 | =item * test_harness |
83f0ef60 | 868 | |
04c692a8 | 869 | Run the test suite with the F<t/harness> controlling program, instead |
531e2078 | 870 | of F<t/TEST>. F<t/harness> is more sophisticated, and uses the |
04c692a8 | 871 | L<Test::Harness> module, thus using this test target supposes that perl |
531e2078 | 872 | mostly works. The main advantage for our purposes is that it prints a |
a44b8c28 S |
873 | detailed summary of failed tests at the end. Also, unlike F<t/TEST>, |
874 | it doesn't redirect stderr to stdout. | |
83f0ef60 | 875 | |
04c692a8 DR |
876 | Note that under Win32 F<t/harness> is always used instead of F<t/TEST>, |
877 | so there is no special "test_harness" target. | |
83f0ef60 | 878 | |
04c692a8 DR |
879 | Under Win32's "test" target you may use the TEST_SWITCHES and |
880 | TEST_FILES environment variables to control the behaviour of | |
531e2078 | 881 | F<t/harness>. This means you can say |
83f0ef60 | 882 | |
04c692a8 DR |
883 | nmake test TEST_FILES="op/*.t" |
884 | nmake test TEST_SWITCHES="-torture" TEST_FILES="op/*.t" | |
83f0ef60 | 885 | |
78087e0a R |
886 | =item * test-notty test_notty |
887 | ||
888 | Sets PERL_SKIP_TTY_TEST to true before running normal test. | |
889 | ||
83f0ef60 JH |
890 | =back |
891 | ||
04c692a8 | 892 | =head2 Parallel tests |
83f0ef60 | 893 | |
04c692a8 | 894 | The core distribution can now run its regression tests in parallel on |
730797bb KW |
895 | Unix-like and Windows platforms. On Unix, instead of running C<make |
896 | test>, set C<TEST_JOBS> in your environment to the number of tests to | |
897 | run in parallel, and run C<make test_harness>. On a Bourne-like shell, | |
898 | this can be done as | |
07aa3531 | 899 | |
04c692a8 | 900 | TEST_JOBS=3 make test_harness # Run 3 tests in parallel |
07aa3531 | 901 | |
04c692a8 DR |
902 | An environment variable is used, rather than parallel make itself, |
903 | because L<TAP::Harness> needs to be able to schedule individual | |
904 | non-conflicting test scripts itself, and there is no standard interface | |
905 | to C<make> utilities to interact with their job schedulers. | |
51a35ef1 | 906 | |
730797bb KW |
907 | Tests are normally run in a logical order, with the sanity tests first, |
908 | then the main tests of the Perl core functionality, then the tests for | |
909 | the non-core modules. On many-core systems, this may not use the | |
910 | hardware as effectively as possible. By also specifying | |
911 | ||
912 | TEST_JOBS=19 PERL_TEST_HARNESS_ASAP=1 make -j19 test_harness | |
913 | ||
914 | you signal that you want the tests to finish in wall-clock time as short | |
915 | as possible. After the sanity tests are completed, this causes the | |
916 | remaining ones to be packed into the available cores as tightly as | |
917 | we know how. This has its greatest effect on slower, many-core systems. | |
918 | Throughput was sped up by 20% on an outmoded 24-core system; less on | |
919 | more recent faster ones with fewer cores. | |
920 | ||
921 | Note that the command line above added a C<-j> parameter to make, so as | |
922 | to cause parallel compilation. This may or may not work on your | |
923 | platform. | |
51a35ef1 | 924 | |
04c692a8 | 925 | =head2 Running tests by hand |
51a35ef1 | 926 | |
9e6670f3 DR |
927 | You can run part of the test suite by hand by using one of the |
928 | following commands from the F<t/> directory: | |
51a35ef1 | 929 | |
04c692a8 | 930 | ./perl -I../lib TEST list-of-.t-files |
51a35ef1 | 931 | |
04c692a8 | 932 | or |
51a35ef1 | 933 | |
04c692a8 | 934 | ./perl -I../lib harness list-of-.t-files |
51a35ef1 | 935 | |
a8d15a22 | 936 | (If you don't specify test scripts, the whole test suite will be run.) |
51a35ef1 | 937 | |
04c692a8 | 938 | =head2 Using F<t/harness> for testing |
51a35ef1 | 939 | |
9e6670f3 | 940 | If you use C<harness> for testing, you have several command line |
531e2078 | 941 | options available to you. The arguments are as follows, and are in the |
9e6670f3 | 942 | order that they must appear if used together. |
51a35ef1 | 943 | |
04c692a8 DR |
944 | harness -v -torture -re=pattern LIST OF FILES TO TEST |
945 | harness -v -torture -re LIST OF PATTERNS TO MATCH | |
07aa3531 | 946 | |
a8d15a22 | 947 | If C<LIST OF FILES TO TEST> is omitted, the file list is obtained from |
531e2078 | 948 | the manifest. The file list may include shell wildcards which will be |
04c692a8 | 949 | expanded out. |
07aa3531 | 950 | |
04c692a8 | 951 | =over 4 |
4ae3d70a | 952 | |
04c692a8 | 953 | =item * -v |
4ae3d70a | 954 | |
04c692a8 DR |
955 | Run the tests under verbose mode so you can see what tests were run, |
956 | and debug output. | |
51a35ef1 | 957 | |
04c692a8 | 958 | =item * -torture |
4ae3d70a | 959 | |
04c692a8 | 960 | Run the torture tests as well as the normal set. |
4ae3d70a | 961 | |
04c692a8 | 962 | =item * -re=PATTERN |
6c41479b | 963 | |
a44b8c28 S |
964 | Filter the file list so that all the test files run match PATTERN. |
965 | Note that this form is distinct from the B<-re LIST OF PATTERNS> form | |
966 | below in that it allows the file list to be provided as well. | |
6c41479b | 967 | |
04c692a8 | 968 | =item * -re LIST OF PATTERNS |
6c41479b | 969 | |
04c692a8 | 970 | Filter the file list so that all the test files run match |
531e2078 | 971 | /(LIST|OF|PATTERNS)/. Note that with this form the patterns are joined |
04c692a8 DR |
972 | by '|' and you cannot supply a list of files, instead the test files |
973 | are obtained from the MANIFEST. | |
6c41479b | 974 | |
04c692a8 | 975 | =back |
6c41479b | 976 | |
04c692a8 | 977 | You can run an individual test by a command similar to |
6c41479b | 978 | |
a8d15a22 | 979 | ./perl -I../lib path/to/foo.t |
6c41479b | 980 | |
04c692a8 DR |
981 | except that the harnesses set up some environment variables that may |
982 | affect the execution of the test: | |
6c41479b JH |
983 | |
984 | =over 4 | |
985 | ||
04c692a8 | 986 | =item * PERL_CORE=1 |
6c41479b | 987 | |
a8d15a22 | 988 | indicates that we're running this test as part of the perl core test |
531e2078 | 989 | suite. This is useful for modules that have a dual life on CPAN. |
6c41479b | 990 | |
04c692a8 | 991 | =item * PERL_DESTRUCT_LEVEL=2 |
6c41479b | 992 | |
04c692a8 | 993 | is set to 2 if it isn't set already (see |
a8d15a22 | 994 | L<perlhacktips/PERL_DESTRUCT_LEVEL>). |
6c41479b | 995 | |
04c692a8 | 996 | =item * PERL |
6c41479b | 997 | |
04c692a8 DR |
998 | (used only by F<t/TEST>) if set, overrides the path to the perl |
999 | executable that should be used to run the tests (the default being | |
1000 | F<./perl>). | |
6c41479b | 1001 | |
04c692a8 | 1002 | =item * PERL_SKIP_TTY_TEST |
6c41479b | 1003 | |
a44b8c28 S |
1004 | if set, tells to skip the tests that need a terminal. It's actually |
1005 | set automatically by the Makefile, but can also be forced artificially | |
1006 | by running 'make test_notty'. | |
6c41479b | 1007 | |
04c692a8 | 1008 | =back |
6c41479b | 1009 | |
04c692a8 | 1010 | =head3 Other environment variables that may influence tests |
6c41479b | 1011 | |
04c692a8 | 1012 | =over 4 |
6c41479b | 1013 | |
04c692a8 | 1014 | =item * PERL_TEST_Net_Ping |
6c41479b | 1015 | |
04c692a8 | 1016 | Setting this variable runs all the Net::Ping modules tests, otherwise |
531e2078 | 1017 | some tests that interact with the outside world are skipped. See |
04c692a8 | 1018 | L<perl58delta>. |
6c41479b | 1019 | |
04c692a8 | 1020 | =item * PERL_TEST_NOVREXX |
cce04beb | 1021 | |
04c692a8 | 1022 | Setting this variable skips the vrexx.t tests for OS2::REXX. |
cce04beb | 1023 | |
04c692a8 | 1024 | =item * PERL_TEST_NUMCONVERTS |
cce04beb | 1025 | |
04c692a8 | 1026 | This sets a variable in op/numconvert.t. |
cce04beb | 1027 | |
ff5db609 TC |
1028 | =item * PERL_TEST_MEMORY |
1029 | ||
1030 | Setting this variable includes the tests in F<t/bigmem/>. This should | |
a44b8c28 S |
1031 | be set to the number of gigabytes of memory available for testing, eg. |
1032 | C<PERL_TEST_MEMORY=4> indicates that tests that require 4GiB of | |
ff5db609 TC |
1033 | available memory can be run safely. |
1034 | ||
04c692a8 | 1035 | =back |
cce04beb | 1036 | |
04c692a8 DR |
1037 | See also the documentation for the Test and Test::Harness modules, for |
1038 | more environment variables that affect testing. | |
cce04beb | 1039 | |
9e7973fa DM |
1040 | =head2 Performance testing |
1041 | ||
1042 | The file F<t/perf/benchmarks> contains snippets of perl code which are | |
1043 | intended to be benchmarked across a range of perls by the | |
1044 | F<Porting/bench.pl> tool. If you fix or enhance a performance issue, you | |
1045 | may want to add a representative code sample to the file, then run | |
1046 | F<bench.pl> against the previous and current perls to see what difference | |
1047 | it has made, and whether anything else has slowed down as a consequence. | |
1048 | ||
1049 | The file F<t/perf/opcount.t> is designed to test whether a particular | |
1050 | code snippet has been compiled into an optree containing specified | |
1051 | numbers of particular op types. This is good for testing whether | |
1052 | optimisations which alter ops, such as converting an C<aelem> op into an | |
1053 | C<aelemfast> op, are really doing that. | |
1054 | ||
1055 | The files F<t/perf/speed.t> and F<t/re/speed.t> are designed to test | |
1056 | things that run thousands of times slower if a particular optimisation | |
1057 | is broken (for example, the utf8 length cache on long utf8 strings). | |
1058 | Add a test that will take a fraction of a second normally, and minutes | |
1059 | otherwise, causing the test file to time out on failure. | |
1060 | ||
ca31f56c JK |
1061 | =head2 Building perl at older commits |
1062 | ||
1063 | In the course of hacking on the Perl core distribution, you may have occasion | |
1064 | to configure, build and test perl at an old commit. Sometimes C<make> will | |
1065 | fail during this process. If that happens, you may be able to salvage the | |
1066 | situation by using the Devel::PatchPerl library from CPAN (not included in the | |
1067 | core) to bring the source code at that commit to a buildable state. | |
1068 | ||
1069 | Here's a real world example, taken from work done to resolve | |
8034715d | 1070 | L<perl #10118|https://github.com/Perl/perl5/issues/10118>. |
ca31f56c JK |
1071 | Use of F<Porting/bisect.pl> had identified commit |
1072 | C<ba77e4cc9d1ceebf472c9c5c18b2377ee47062e6> as the commit in which a bug was | |
1073 | corrected. To confirm, a P5P developer wanted to configure and build perl at | |
1074 | commit C<ba77e4c^> (presumably "bad") and then at C<ba77e4c> (presumably | |
1075 | "good"). Normal configuration and build was attempted: | |
1076 | ||
1077 | $ sh ./Configure -des -Dusedevel | |
1078 | $ make test_prep | |
1079 | ||
1080 | C<make>, however, failed with output (excerpted) like this: | |
1081 | ||
1082 | cc -fstack-protector -L/usr/local/lib -o miniperl \ | |
1083 | gv.o toke.o perly.o pad.o regcomp.o dump.o util.o \ | |
1084 | mg.o reentr.o mro.o hv.o av.o run.o pp_hot.o sv.o \ | |
1085 | pp.o scope.o pp_ctl.o pp_sys.o doop.o doio.o regexec.o \ | |
1086 | utf8.o taint.o deb.o universal.o globals.o perlio.o \ | |
8c3a0f6c | 1087 | numeric.o mathoms.o locale.o pp_pack.o pp_sort.o \ |
ca31f56c JK |
1088 | miniperlmain.o opmini.o perlmini.o |
1089 | pp.o: In function `Perl_pp_pow': | |
1090 | pp.c:(.text+0x2db9): undefined reference to `pow' | |
1091 | ... | |
1092 | collect2: error: ld returned 1 exit status | |
1093 | makefile:348: recipe for target 'miniperl' failed | |
1094 | make: *** [miniperl] Error 1 | |
1095 | ||
1096 | Another P5P contributor recommended installation and use of Devel::PatchPerl | |
1097 | for this situation, first to determine the version of perl at the commit in | |
1098 | question, then to patch the source code at that point to facilitate a build. | |
1099 | ||
1100 | $ perl -MDevel::PatchPerl -e \ | |
1101 | 'print Devel::PatchPerl->determine_version("/path/to/sourcecode"), "\n";' | |
1102 | 5.11.1 | |
1103 | $ perl -MDevel::PatchPerl -e \ | |
1104 | 'Devel::PatchPerl->patch_source("5.11.1", "/path/to/sourcecode");' | |
1105 | ||
1106 | Once the source was patched, C<./Configure> and C<make test_prep> were called | |
1107 | and completed successfully, enabling confirmation of the findings in RT | |
1108 | #72414. | |
1109 | ||
04c692a8 | 1110 | =head1 MORE READING FOR GUTS HACKERS |
cce04beb | 1111 | |
04c692a8 | 1112 | To hack on the Perl guts, you'll need to read the following things: |
cce04beb | 1113 | |
04c692a8 | 1114 | =over 4 |
cce04beb | 1115 | |
04c692a8 | 1116 | =item * L<perlsource> |
b8ddf6b3 | 1117 | |
531e2078 | 1118 | An overview of the Perl source tree. This will help you find the files |
04c692a8 | 1119 | you're looking for. |
b8ddf6b3 | 1120 | |
04c692a8 | 1121 | =item * L<perlinterp> |
b8ddf6b3 | 1122 | |
04c692a8 DR |
1123 | An overview of the Perl interpreter source code and some details on how |
1124 | Perl does what it does. | |
b8ddf6b3 | 1125 | |
04c692a8 | 1126 | =item * L<perlhacktut> |
b8ddf6b3 | 1127 | |
04c692a8 | 1128 | This document walks through the creation of a small patch to Perl's C |
531e2078 | 1129 | code. If you're just getting started with Perl core hacking, this will |
04c692a8 | 1130 | help you understand how it works. |
b8ddf6b3 | 1131 | |
04c692a8 | 1132 | =item * L<perlhacktips> |
b8ddf6b3 | 1133 | |
531e2078 | 1134 | More details on hacking the Perl core. This document focuses on lower |
04c692a8 DR |
1135 | level details such as how to write tests, compilation issues, |
1136 | portability, debugging, etc. | |
b8ddf6b3 | 1137 | |
04c692a8 | 1138 | If you plan on doing serious C hacking, make sure to read this. |
b8ddf6b3 | 1139 | |
04c692a8 | 1140 | =item * L<perlguts> |
b8ddf6b3 | 1141 | |
04c692a8 | 1142 | This is of paramount importance, since it's the documentation of what |
531e2078 | 1143 | goes where in the Perl source. Read it over a couple of times and it |
04c692a8 DR |
1144 | might start to make sense - don't worry if it doesn't yet, because the |
1145 | best way to study it is to read it in conjunction with poking at Perl | |
1146 | source, and we'll do that later on. | |
b8ddf6b3 | 1147 | |
04c692a8 DR |
1148 | Gisle Aas's "illustrated perlguts", also known as I<illguts>, has very |
1149 | helpful pictures: | |
9965345d | 1150 | |
082a0fe7 | 1151 | L<https://metacpan.org/release/RURBAN/illguts-0.49> |
9965345d | 1152 | |
04c692a8 | 1153 | =item * L<perlxstut> and L<perlxs> |
f1fac472 | 1154 | |
04c692a8 DR |
1155 | A working knowledge of XSUB programming is incredibly useful for core |
1156 | hacking; XSUBs use techniques drawn from the PP code, the portion of | |
531e2078 | 1157 | the guts that actually executes a Perl program. It's a lot gentler to |
04c692a8 DR |
1158 | learn those techniques from simple examples and explanation than from |
1159 | the core itself. | |
f1fac472 | 1160 | |
04c692a8 | 1161 | =item * L<perlapi> |
f1fac472 | 1162 | |
04c692a8 DR |
1163 | The documentation for the Perl API explains what some of the internal |
1164 | functions do, as well as the many macros used in the source. | |
f1fac472 | 1165 | |
04c692a8 | 1166 | =item * F<Porting/pumpkin.pod> |
f1fac472 | 1167 | |
04c692a8 | 1168 | This is a collection of words of wisdom for a Perl porter; some of it |
66c65f79 | 1169 | is only useful to the pumpkin holders, but most of it applies to anyone |
04c692a8 | 1170 | wanting to go about Perl development. |
f1fac472 | 1171 | |
04c692a8 | 1172 | =back |
f1fac472 | 1173 | |
04c692a8 | 1174 | =head1 CPAN TESTERS AND PERL SMOKERS |
f1fac472 | 1175 | |
71c89d21 | 1176 | The CPAN testers ( L<http://cpantesters.org/> ) are a group of volunteers |
04c692a8 | 1177 | who test CPAN modules on a variety of platforms. |
b8ddf6b3 | 1178 | |
71c89d21 MM |
1179 | Perl Smokers ( L<https://www.nntp.perl.org/group/perl.daily-build/> and |
1180 | L<https://www.nntp.perl.org/group/perl.daily-build.reports/> ) | |
04c692a8 DR |
1181 | automatically test Perl source releases on platforms with various |
1182 | configurations. | |
f1fac472 | 1183 | |
531e2078 | 1184 | Both efforts welcome volunteers. In order to get involved in smoke |
04c692a8 | 1185 | testing of the perl itself visit |
c23f766f | 1186 | L<https://metacpan.org/release/Test-Smoke>. In order to start smoke |
04c692a8 | 1187 | testing CPAN modules visit |
c23f766f DB |
1188 | L<https://metacpan.org/release/CPANPLUS-YACSmoke> or |
1189 | L<https://metacpan.org/release/minismokebox> or | |
1190 | L<https://metacpan.org/release/CPAN-Reporter>. | |
f1fac472 | 1191 | |
04c692a8 | 1192 | =head1 WHAT NEXT? |
a422fd2d | 1193 | |
04c692a8 DR |
1194 | If you've read all the documentation in the document and the ones |
1195 | listed above, you're more than ready to hack on Perl. | |
a422fd2d | 1196 | |
04c692a8 | 1197 | Here's some more recommendations |
a422fd2d | 1198 | |
04c692a8 | 1199 | =over 4 |
a422fd2d SC |
1200 | |
1201 | =item * | |
1202 | ||
1203 | Subscribe to perl5-porters, follow the patches and try and understand | |
1204 | them; don't be afraid to ask if there's a portion you're not clear on - | |
1205 | who knows, you may unearth a bug in the patch... | |
1206 | ||
1207 | =item * | |
1208 | ||
04c692a8 | 1209 | Do read the README associated with your operating system, e.g. |
531e2078 | 1210 | README.aix on the IBM AIX OS. Don't hesitate to supply patches to that |
04c692a8 | 1211 | README if you find anything missing or changed over a new OS release. |
a1f349fd MB |
1212 | |
1213 | =item * | |
1214 | ||
a422fd2d | 1215 | Find an area of Perl that seems interesting to you, and see if you can |
a44b8c28 S |
1216 | work out how it works. Scan through the source, and step over it in |
1217 | the debugger. Play, poke, investigate, fiddle! You'll probably get to | |
04c692a8 DR |
1218 | understand not just your chosen area but a much wider range of |
1219 | F<perl>'s activity as well, and probably sooner than you'd think. | |
a422fd2d SC |
1220 | |
1221 | =back | |
1222 | ||
04c692a8 | 1223 | =head2 "The Road goes ever on and on, down from the door where it began." |
a422fd2d | 1224 | |
04c692a8 | 1225 | If you can do these things, you've started on the long road to Perl |
531e2078 | 1226 | porting. Thanks for wanting to help make Perl better - and happy |
04c692a8 | 1227 | hacking! |
a422fd2d | 1228 | |
4ac71550 TC |
1229 | =head2 Metaphoric Quotations |
1230 | ||
1231 | If you recognized the quote about the Road above, you're in luck. | |
1232 | ||
04c692a8 | 1233 | Most software projects begin each file with a literal description of |
531e2078 | 1234 | each file's purpose. Perl instead begins each with a literary allusion |
04c692a8 | 1235 | to that file's purpose. |
4ac71550 | 1236 | |
04c692a8 | 1237 | Like chapters in many books, all top-level Perl source files (along |
9e6670f3 DR |
1238 | with a few others here and there) begin with an epigrammatic |
1239 | inscription that alludes, indirectly and metaphorically, to the | |
1240 | material you're about to read. | |
4ac71550 | 1241 | |
a8d15a22 | 1242 | Quotations are taken from writings of J.R.R. Tolkien pertaining to his |
531e2078 | 1243 | Legendarium, almost always from I<The Lord of the Rings>. Chapters and |
4ac71550 TC |
1244 | page numbers are given using the following editions: |
1245 | ||
1246 | =over 4 | |
1247 | ||
04c692a8 | 1248 | =item * |
4ac71550 | 1249 | |
531e2078 | 1250 | I<The Hobbit>, by J.R.R. Tolkien. The hardcover, 70th-anniversary |
04c692a8 DR |
1251 | edition of 2007 was used, published in the UK by Harper Collins |
1252 | Publishers and in the US by the Houghton Mifflin Company. | |
4ac71550 TC |
1253 | |
1254 | =item * | |
1255 | ||
531e2078 | 1256 | I<The Lord of the Rings>, by J.R.R. Tolkien. The hardcover, |
04c692a8 DR |
1257 | 50th-anniversary edition of 2004 was used, published in the UK by |
1258 | Harper Collins Publishers and in the US by the Houghton Mifflin | |
1259 | Company. | |
4ac71550 TC |
1260 | |
1261 | =item * | |
1262 | ||
04c692a8 DR |
1263 | I<The Lays of Beleriand>, by J.R.R. Tolkien and published posthumously |
1264 | by his son and literary executor, C.J.R. Tolkien, being the 3rd of the | |
531e2078 | 1265 | 12 volumes in Christopher's mammoth I<History of Middle Earth>. Page |
04c692a8 DR |
1266 | numbers derive from the hardcover edition, first published in 1983 by |
1267 | George Allen & Unwin; no page numbers changed for the special 3-volume | |
1268 | omnibus edition of 2002 or the various trade-paper editions, all again | |
1269 | now by Harper Collins or Houghton Mifflin. | |
4ac71550 TC |
1270 | |
1271 | =back | |
1272 | ||
04c692a8 DR |
1273 | Other JRRT books fair game for quotes would thus include I<The |
1274 | Adventures of Tom Bombadil>, I<The Silmarillion>, I<Unfinished Tales>, | |
1275 | and I<The Tale of the Children of Hurin>, all but the first | |
531e2078 | 1276 | posthumously assembled by CJRT. But I<The Lord of the Rings> itself is |
04c692a8 DR |
1277 | perfectly fine and probably best to quote from, provided you can find a |
1278 | suitable quote there. | |
4ac71550 | 1279 | |
04c692a8 DR |
1280 | So if you were to supply a new, complete, top-level source file to add |
1281 | to Perl, you should conform to this peculiar practice by yourself | |
1282 | selecting an appropriate quotation from Tolkien, retaining the original | |
1283 | spelling and punctuation and using the same format the rest of the | |
531e2078 | 1284 | quotes are in. Indirect and oblique is just fine; remember, it's a |
04c692a8 | 1285 | metaphor, so being meta is, after all, what it's for. |
4ac71550 | 1286 | |
e8cd7eae GS |
1287 | =head1 AUTHOR |
1288 | ||
04c692a8 DR |
1289 | This document was originally written by Nathan Torkington, and is |
1290 | maintained by the perl5-porters mailing list. |