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1 | @node Contributing |
2 | @chapter Contributing | |
3 | ||
4 | This project is a cooperative effort, and we need your help to make it | |
5 | grow! Please get in touch with us on @email{guix-devel@@gnu.org} and | |
6 | @code{#guix} on the Freenode IRC network. We welcome ideas, bug | |
7 | reports, patches, and anything that may be helpful to the project. We | |
8 | particularly welcome help on packaging (@pxref{Packaging Guidelines}). | |
9 | ||
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10 | @cindex code of conduct, of contributors |
11 | @cindex contributor covenant | |
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12 | We want to provide a warm, friendly, and harassment-free environment, so |
13 | that anyone can contribute to the best of their abilities. To this end | |
14 | our project uses a ``Contributor Covenant'', which was adapted from | |
15 | @url{http://contributor-covenant.org/}. You can find a local version in | |
16 | the @file{CODE-OF-CONDUCT} file in the source tree. | |
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18 | Contributors are not required to use their legal name in patches and |
19 | on-line communication; they can use any name or pseudonym of their | |
20 | choice. | |
21 | ||
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22 | @menu |
23 | * Building from Git:: The latest and greatest. | |
24 | * Running Guix Before It Is Installed:: Hacker tricks. | |
25 | * The Perfect Setup:: The right tools. | |
26 | * Coding Style:: Hygiene of the contributor. | |
27 | * Submitting Patches:: Share your work. | |
28 | @end menu | |
29 | ||
30 | @node Building from Git | |
31 | @section Building from Git | |
32 | ||
33 | If you want to hack Guix itself, it is recommended to use the latest | |
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34 | version from the Git repository: |
35 | ||
36 | @example | |
37 | git clone https://git.savannah.gnu.org/git/guix.git | |
38 | @end example | |
39 | ||
40 | When building Guix from a checkout, | |
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41 | the following packages are required in addition to those mentioned in |
42 | the installation instructions (@pxref{Requirements}). | |
43 | ||
44 | @itemize | |
45 | @item @url{http://gnu.org/software/autoconf/, GNU Autoconf}; | |
46 | @item @url{http://gnu.org/software/automake/, GNU Automake}; | |
47 | @item @url{http://gnu.org/software/gettext/, GNU Gettext}; | |
0431ed00 | 48 | @item @url{http://gnu.org/software/texinfo/, GNU Texinfo}; |
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49 | @item @url{http://www.graphviz.org/, Graphviz}; |
50 | @item @url{http://www.gnu.org/software/help2man/, GNU Help2man (optional)}. | |
51 | @end itemize | |
52 | ||
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53 | The easiest way to set up a development environment for Guix is, of |
54 | course, by using Guix! The following command starts a new shell where | |
55 | all the dependencies and appropriate environment variables are set up to | |
56 | hack on Guix: | |
8c01b9d0 | 57 | |
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58 | @example |
59 | guix environment guix | |
60 | @end example | |
61 | ||
62 | @xref{Invoking guix environment}, for more information on that command. | |
63 | Extra dependencies can be added with @option{--ad-hoc}: | |
64 | ||
65 | @example | |
66 | guix environment guix --ad-hoc help2man git strace | |
67 | @end example | |
68 | ||
69 | Run @command{./bootstrap} to generate the build system infrastructure | |
70 | using Autoconf and Automake. If you get an error like this one: | |
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71 | |
72 | @example | |
73 | configure.ac:46: error: possibly undefined macro: PKG_CHECK_MODULES | |
74 | @end example | |
75 | ||
5fb95cc5 | 76 | @noindent |
8c01b9d0 | 77 | it probably means that Autoconf couldn’t find @file{pkg.m4}, which is |
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78 | provided by pkg-config. Make sure that @file{pkg.m4} is available. The |
79 | same holds for the @file{guile.m4} set of macros provided by Guile. For | |
80 | instance, if you installed Automake in @file{/usr/local}, it wouldn’t | |
81 | look for @file{.m4} files in @file{/usr/share}. In that case, you have | |
82 | to invoke the following command: | |
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83 | |
84 | @example | |
85 | export ACLOCAL_PATH=/usr/share/aclocal | |
86 | @end example | |
87 | ||
aabe6d38 | 88 | @xref{Macro Search Path,,, automake, The GNU Automake Manual}, for |
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89 | more information. |
90 | ||
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91 | Then, run @command{./configure} as usual. Make sure to pass |
92 | @code{--localstatedir=@var{directory}} where @var{directory} is the | |
93 | @code{localstatedir} value used by your current installation (@pxref{The | |
94 | Store}, for information about this). | |
8c01b9d0 | 95 | |
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96 | Finally, you have to invoke @code{make check} to run tests |
97 | (@pxref{Running the Test Suite}). If anything | |
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98 | fails, take a look at installation instructions (@pxref{Installation}) |
99 | or send a message to the @email{guix-devel@@gnu.org, mailing list}. | |
100 | ||
101 | ||
102 | @node Running Guix Before It Is Installed | |
103 | @section Running Guix Before It Is Installed | |
104 | ||
105 | In order to keep a sane working environment, you will find it useful to | |
106 | test the changes made in your local source tree checkout without | |
107 | actually installing them. So that you can distinguish between your | |
108 | ``end-user'' hat and your ``motley'' costume. | |
109 | ||
110 | To that end, all the command-line tools can be used even if you have not | |
111 | run @code{make install}. To do that, prefix each command with | |
112 | @command{./pre-inst-env} (the @file{pre-inst-env} script lives in the | |
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113 | top build tree of Guix), as in@footnote{The @option{-E} flag to |
114 | @command{sudo} guarantees that @code{GUILE_LOAD_PATH} is correctly set | |
115 | such that @command{guix-daemon} and the tools it uses can find the Guile | |
116 | modules they need.}: | |
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117 | |
118 | @example | |
67441b9a | 119 | $ sudo -E ./pre-inst-env guix-daemon --build-users-group=guixbuild |
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120 | $ ./pre-inst-env guix build hello |
121 | @end example | |
122 | ||
123 | @noindent | |
124 | Similarly, for a Guile session using the Guix modules: | |
125 | ||
126 | @example | |
127 | $ ./pre-inst-env guile -c '(use-modules (guix utils)) (pk (%current-system))' | |
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128 | |
129 | ;;; ("x86_64-linux") | |
130 | @end example | |
131 | ||
132 | @noindent | |
133 | @cindex REPL | |
134 | @cindex read-eval-print loop | |
135 | @dots{} and for a REPL (@pxref{Using Guile Interactively,,, guile, Guile | |
136 | Reference Manual}): | |
137 | ||
138 | @example | |
139 | $ ./pre-inst-env guile | |
140 | scheme@@(guile-user)> ,use(guix) | |
141 | scheme@@(guile-user)> ,use(gnu) | |
142 | scheme@@(guile-user)> (define snakes | |
143 | (fold-packages | |
144 | (lambda (package lst) | |
145 | (if (string-prefix? "python" | |
146 | (package-name package)) | |
147 | (cons package lst) | |
148 | lst)) | |
149 | '())) | |
150 | scheme@@(guile-user)> (length snakes) | |
151 | $1 = 361 | |
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152 | @end example |
153 | ||
154 | The @command{pre-inst-env} script sets up all the environment variables | |
155 | necessary to support this, including @env{PATH} and @env{GUILE_LOAD_PATH}. | |
156 | ||
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157 | Note that @command{./pre-inst-env guix pull} does @emph{not} upgrade the |
158 | local source tree; it simply updates the @file{~/.config/guix/latest} | |
159 | symlink (@pxref{Invoking guix pull}). Run @command{git pull} instead if | |
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160 | you want to upgrade your local source tree.@footnote{If you would like |
161 | to set up @command{guix} to use your Git checkout, you can point the | |
162 | @file{~/.config/guix/latest} symlink to your Git checkout directory. | |
163 | If you are the sole user of your system, you may also consider pointing | |
164 | the @file{/root/.config/guix/latest} symlink to point to | |
165 | @file{~/.config/guix/latest}; this way it will always use the same | |
166 | @command{guix} as your user does.} | |
ef54b61d | 167 | |
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168 | |
169 | @node The Perfect Setup | |
170 | @section The Perfect Setup | |
171 | ||
172 | The Perfect Setup to hack on Guix is basically the perfect setup used | |
173 | for Guile hacking (@pxref{Using Guile in Emacs,,, guile, Guile Reference | |
174 | Manual}). First, you need more than an editor, you need | |
175 | @url{http://www.gnu.org/software/emacs, Emacs}, empowered by the | |
176 | wonderful @url{http://nongnu.org/geiser/, Geiser}. | |
177 | ||
178 | Geiser allows for interactive and incremental development from within | |
179 | Emacs: code compilation and evaluation from within buffers, access to | |
180 | on-line documentation (docstrings), context-sensitive completion, | |
181 | @kbd{M-.} to jump to an object definition, a REPL to try out your code, | |
182 | and more (@pxref{Introduction,,, geiser, Geiser User Manual}). For | |
183 | convenient Guix development, make sure to augment Guile’s load path so | |
184 | that it finds source files from your checkout: | |
185 | ||
186 | @lisp | |
187 | ;; @r{Assuming the Guix checkout is in ~/src/guix.} | |
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188 | (with-eval-after-load 'geiser-guile |
189 | (add-to-list 'geiser-guile-load-path "~/src/guix")) | |
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190 | @end lisp |
191 | ||
192 | To actually edit the code, Emacs already has a neat Scheme mode. But in | |
193 | addition to that, you must not miss | |
194 | @url{http://www.emacswiki.org/emacs/ParEdit, Paredit}. It provides | |
195 | facilities to directly operate on the syntax tree, such as raising an | |
196 | s-expression or wrapping it, swallowing or rejecting the following | |
197 | s-expression, etc. | |
198 | ||
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199 | @cindex code snippets |
200 | @cindex templates | |
201 | @cindex reducing boilerplate | |
202 | We also provide templates for common git commit messages and package | |
203 | definitions in the @file{etc/snippets} directory. These templates can | |
204 | be used with @url{http://joaotavora.github.io/yasnippet/, YASnippet} to | |
205 | expand short trigger strings to interactive text snippets. You may want | |
206 | to add the snippets directory to the @var{yas-snippet-dirs} variable in | |
207 | Emacs. | |
208 | ||
209 | @lisp | |
210 | ;; @r{Assuming the Guix checkout is in ~/src/guix.} | |
211 | (with-eval-after-load 'yasnippet | |
212 | (add-to-list 'yas-snippet-dirs "~/src/guix/etc/snippets")) | |
213 | @end lisp | |
214 | ||
215 | The commit message snippets depend on @url{https://magit.vc/, Magit} to | |
216 | display staged files. When editing a commit message type @code{add} | |
217 | followed by @kbd{TAB} to insert a commit message template for adding a | |
218 | package; type @code{update} followed by @kbd{TAB} to insert a template | |
219 | for updating a package. | |
220 | ||
221 | The main snippet for @code{scheme-mode} is triggered by typing | |
222 | @code{package...} followed by @kbd{TAB}. This snippet also inserts the | |
223 | trigger string @code{origin...}, which can be expanded further. The | |
224 | @code{origin} snippet in turn may insert other trigger strings ending on | |
225 | @code{...}, which also can be expanded further. | |
226 | ||
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227 | |
228 | @node Coding Style | |
229 | @section Coding Style | |
230 | ||
231 | In general our code follows the GNU Coding Standards (@pxref{Top,,, | |
232 | standards, GNU Coding Standards}). However, they do not say much about | |
233 | Scheme, so here are some additional rules. | |
234 | ||
235 | @menu | |
236 | * Programming Paradigm:: How to compose your elements. | |
237 | * Modules:: Where to store your code? | |
238 | * Data Types and Pattern Matching:: Implementing data structures. | |
239 | * Formatting Code:: Writing conventions. | |
240 | @end menu | |
241 | ||
242 | @node Programming Paradigm | |
243 | @subsection Programming Paradigm | |
244 | ||
245 | Scheme code in Guix is written in a purely functional style. One | |
246 | exception is code that involves input/output, and procedures that | |
247 | implement low-level concepts, such as the @code{memoize} procedure. | |
248 | ||
249 | @node Modules | |
250 | @subsection Modules | |
251 | ||
252 | Guile modules that are meant to be used on the builder side must live in | |
253 | the @code{(guix build @dots{})} name space. They must not refer to | |
254 | other Guix or GNU modules. However, it is OK for a ``host-side'' module | |
255 | to use a build-side module. | |
256 | ||
257 | Modules that deal with the broader GNU system should be in the | |
258 | @code{(gnu @dots{})} name space rather than @code{(guix @dots{})}. | |
259 | ||
260 | @node Data Types and Pattern Matching | |
261 | @subsection Data Types and Pattern Matching | |
262 | ||
263 | The tendency in classical Lisp is to use lists to represent everything, | |
264 | and then to browse them ``by hand'' using @code{car}, @code{cdr}, | |
265 | @code{cadr}, and co. There are several problems with that style, | |
266 | notably the fact that it is hard to read, error-prone, and a hindrance | |
267 | to proper type error reports. | |
268 | ||
269 | Guix code should define appropriate data types (for instance, using | |
270 | @code{define-record-type*}) rather than abuse lists. In addition, it | |
271 | should use pattern matching, via Guile’s @code{(ice-9 match)} module, | |
272 | especially when matching lists. | |
273 | ||
274 | @node Formatting Code | |
275 | @subsection Formatting Code | |
276 | ||
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277 | @cindex formatting code |
278 | @cindex coding style | |
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279 | When writing Scheme code, we follow common wisdom among Scheme |
280 | programmers. In general, we follow the | |
281 | @url{http://mumble.net/~campbell/scheme/style.txt, Riastradh's Lisp | |
282 | Style Rules}. This document happens to describe the conventions mostly | |
283 | used in Guile’s code too. It is very thoughtful and well written, so | |
284 | please do read it. | |
285 | ||
286 | Some special forms introduced in Guix, such as the @code{substitute*} | |
287 | macro, have special indentation rules. These are defined in the | |
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288 | @file{.dir-locals.el} file, which Emacs automatically uses. Also note |
289 | that Emacs-Guix provides @code{guix-devel-mode} mode that indents and | |
290 | highlights Guix code properly (@pxref{Development,,, emacs-guix, The | |
291 | Emacs-Guix Reference Manual}). | |
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292 | |
293 | @cindex indentation, of code | |
294 | @cindex formatting, of code | |
295 | If you do not use Emacs, please make sure to let your editor knows these | |
296 | rules. To automatically indent a package definition, you can also run: | |
297 | ||
298 | @example | |
557d9c8d | 299 | ./etc/indent-code.el gnu/packages/@var{file}.scm @var{package} |
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300 | @end example |
301 | ||
302 | @noindent | |
303 | This automatically indents the definition of @var{package} in | |
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304 | @file{gnu/packages/@var{file}.scm} by running Emacs in batch mode. To |
305 | indent a whole file, omit the second argument: | |
306 | ||
307 | @example | |
308 | ./etc/indent-code.el gnu/services/@var{file}.scm | |
309 | @end example | |
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310 | |
311 | We require all top-level procedures to carry a docstring. This | |
312 | requirement can be relaxed for simple private procedures in the | |
313 | @code{(guix build @dots{})} name space, though. | |
314 | ||
315 | Procedures should not have more than four positional parameters. Use | |
316 | keyword parameters for procedures that take more than four parameters. | |
317 | ||
318 | ||
319 | @node Submitting Patches | |
320 | @section Submitting Patches | |
321 | ||
322 | Development is done using the Git distributed version control system. | |
323 | Thus, access to the repository is not strictly necessary. We welcome | |
324 | contributions in the form of patches as produced by @code{git | |
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325 | format-patch} sent to the @email{guix-patches@@gnu.org} mailing list. |
326 | ||
327 | This mailing list is backed by a Debbugs instance accessible at | |
328 | @uref{https://bugs.gnu.org/guix-patches}, which allows us to keep track | |
329 | of submissions. Each message sent to that mailing list gets a new | |
330 | tracking number assigned; people can then follow up on the submission by | |
331 | sending email to @code{@var{NNN}@@debbugs.gnu.org}, where @var{NNN} is | |
5a183a1e | 332 | the tracking number (@pxref{Sending a Patch Series}). |
230efa87 | 333 | |
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334 | Please write commit logs in the ChangeLog format (@pxref{Change Logs,,, |
335 | standards, GNU Coding Standards}); you can check the commit history for | |
336 | examples. | |
337 | ||
338 | Before submitting a patch that adds or modifies a package definition, | |
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339 | please run through this check list: |
340 | ||
341 | @enumerate | |
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342 | @item |
343 | If the authors of the packaged software provide a cryptographic | |
344 | signature for the release tarball, make an effort to verify the | |
345 | authenticity of the archive. For a detached GPG signature file this | |
346 | would be done with the @code{gpg --verify} command. | |
347 | ||
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348 | @item |
349 | Take some time to provide an adequate synopsis and description for the | |
350 | package. @xref{Synopses and Descriptions}, for some guidelines. | |
351 | ||
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352 | @item |
353 | Run @code{guix lint @var{package}}, where @var{package} is the | |
8c01b9d0 | 354 | name of the new or modified package, and fix any errors it reports |
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355 | (@pxref{Invoking guix lint}). |
356 | ||
357 | @item | |
358 | Make sure the package builds on your platform, using @code{guix build | |
359 | @var{package}}. | |
360 | ||
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361 | @item |
362 | @cindex bundling | |
363 | Make sure the package does not use bundled copies of software already | |
364 | available as separate packages. | |
365 | ||
366 | Sometimes, packages include copies of the source code of their | |
367 | dependencies as a convenience for users. However, as a distribution, we | |
368 | want to make sure that such packages end up using the copy we already | |
369 | have in the distribution, if there is one. This improves resource usage | |
370 | (the dependency is built and stored only once), and allows the | |
371 | distribution to make transverse changes such as applying security | |
372 | updates for a given software package in a single place and have them | |
373 | affect the whole system---something that bundled copies prevent. | |
374 | ||
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375 | @item |
376 | Take a look at the profile reported by @command{guix size} | |
377 | (@pxref{Invoking guix size}). This will allow you to notice references | |
378 | to other packages unwillingly retained. It may also help determine | |
379 | whether to split the package (@pxref{Packages with Multiple Outputs}), | |
380 | and which optional dependencies should be used. | |
381 | ||
382 | @item | |
383 | For important changes, check that dependent package (if applicable) are | |
384 | not affected by the change; @code{guix refresh --list-dependent | |
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385 | @var{package}} will help you do that (@pxref{Invoking guix refresh}). |
386 | ||
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387 | @c See <https://lists.gnu.org/archive/html/guix-devel/2016-10/msg00933.html>. |
388 | @cindex branching strategy | |
389 | @cindex rebuild scheduling strategy | |
390 | Depending on the number of dependent packages and thus the amount of | |
391 | rebuilding induced, commits go to different branches, along these lines: | |
392 | ||
393 | @table @asis | |
394 | @item 300 dependent packages or less | |
395 | @code{master} branch (non-disruptive changes). | |
396 | ||
397 | @item between 300 and 1,200 dependent packages | |
398 | @code{staging} branch (non-disruptive changes). This branch is intended | |
399 | to be merged in @code{master} every 3 weeks or so. Topical changes | |
400 | (e.g., an update of the GNOME stack) can instead go to a specific branch | |
401 | (say, @code{gnome-updates}). | |
402 | ||
403 | @item more than 1,200 dependent packages | |
404 | @code{core-updates} branch (may include major and potentially disruptive | |
405 | changes). This branch is intended to be merged in @code{master} every | |
406 | 2.5 months or so. | |
407 | @end table | |
408 | ||
409 | All these branches are tracked by our build farm | |
410 | and merged into @code{master} once | |
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411 | everything has been successfully built. This allows us to fix issues |
412 | before they hit users, and to reduce the window during which pre-built | |
413 | binaries are not available. | |
414 | ||
d23c20f1 | 415 | @item |
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416 | @cindex determinism, of build processes |
417 | @cindex reproducible builds, checking | |
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418 | Check whether the package's build process is deterministic. This |
419 | typically means checking whether an independent build of the package | |
420 | yields the exact same result that you obtained, bit for bit. | |
421 | ||
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422 | A simple way to do that is by building the same package several times in |
423 | a row on your machine (@pxref{Invoking guix build}): | |
424 | ||
425 | @example | |
426 | guix build --rounds=2 my-package | |
427 | @end example | |
428 | ||
429 | This is enough to catch a class of common non-determinism issues, such | |
430 | as timestamps or randomly-generated output in the build result. | |
431 | ||
432 | Another option is to use @command{guix challenge} (@pxref{Invoking guix | |
433 | challenge}). You may run it once the package has been committed and | |
434 | built by @code{hydra.gnu.org} to check whether it obtains the same | |
435 | result as you did. Better yet: Find another machine that can build it | |
436 | and run @command{guix publish}. Since the remote build machine is | |
437 | likely different from yours, this can catch non-determinism issues | |
438 | related to the hardware---e.g., use of different instruction set | |
439 | extensions---or to the operating system kernel---e.g., reliance on | |
440 | @code{uname} or @file{/proc} files. | |
d23c20f1 | 441 | |
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442 | @item |
443 | When writing documentation, please use gender-neutral wording when | |
444 | referring to people, such as | |
445 | @uref{https://en.wikipedia.org/wiki/Singular_they, singular | |
446 | ``they''@comma{} ``their''@comma{} ``them''}, and so forth. | |
447 | ||
3a78fab8 | 448 | @item |
449 | Verify that your patch contains only one set of related changes. | |
450 | Bundling unrelated changes together makes reviewing harder and slower. | |
451 | ||
452 | Examples of unrelated changes include the addition of several packages, | |
453 | or a package update along with fixes to that package. | |
454 | ||
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455 | @item |
456 | Please follow our code formatting rules, possibly running the | |
557d9c8d | 457 | @command{etc/indent-code.el} script to do that automatically for you |
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458 | (@pxref{Formatting Code}). |
459 | ||
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460 | @end enumerate |
461 | ||
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462 | When posting a patch to the mailing list, use @samp{[PATCH] @dots{}} as |
463 | a subject. You may use your email client or the @command{git | |
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464 | send-email} command (@pxref{Sending a Patch Series}). We prefer to get |
465 | patches in plain text messages, either inline or as MIME attachments. | |
466 | You are advised to pay attention if your email client changes anything | |
467 | like line breaks or indentation which could potentially break the | |
468 | patches. | |
469 | ||
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470 | When a bug is resolved, please close the thread by sending an email to |
471 | @email{@var{NNN}-done@@debbugs.gnu.org}. | |
472 | ||
5a183a1e JN |
473 | @unnumberedsubsec Sending a Patch Series |
474 | @anchor{Sending a Patch Series} | |
475 | @cindex patch series | |
476 | @cindex @code{git send-email} | |
477 | @cindex @code{git-send-email} | |
478 | ||
479 | When sending a patch series (e.g., using @code{git send-email}), please | |
480 | first send one message to @email{guix-patches@@gnu.org}, and then send | |
481 | subsequent patches to @email{@var{NNN}@@debbugs.gnu.org} to make sure | |
482 | they are kept together. See | |
483 | @uref{https://debbugs.gnu.org/Advanced.html, the Debbugs documentation} | |
484 | for more information. | |
485 | @c Debbugs bug: https://debbugs.gnu.org/db/15/15361.html |