l10n: fixes to German translation
[git/git.git] / Documentation / SubmittingPatches
1 Here are some guidelines for people who want to contribute their code
2 to this software.
3
4 (0) Decide what to base your work on.
5
6 In general, always base your work on the oldest branch that your
7 change is relevant to.
8
9 - A bugfix should be based on 'maint' in general. If the bug is not
10 present in 'maint', base it on 'master'. For a bug that's not yet
11 in 'master', find the topic that introduces the regression, and
12 base your work on the tip of the topic.
13
14 - A new feature should be based on 'master' in general. If the new
15 feature depends on a topic that is in 'pu', but not in 'master',
16 base your work on the tip of that topic.
17
18 - Corrections and enhancements to a topic not yet in 'master' should
19 be based on the tip of that topic. If the topic has not been merged
20 to 'next', it's alright to add a note to squash minor corrections
21 into the series.
22
23 - In the exceptional case that a new feature depends on several topics
24 not in 'master', start working on 'next' or 'pu' privately and send
25 out patches for discussion. Before the final merge, you may have to
26 wait until some of the dependent topics graduate to 'master', and
27 rebase your work.
28
29 - Some parts of the system have dedicated maintainers with their own
30 repositories (see the section "Subsystems" below). Changes to
31 these parts should be based on their trees.
32
33 To find the tip of a topic branch, run "git log --first-parent
34 master..pu" and look for the merge commit. The second parent of this
35 commit is the tip of the topic branch.
36
37 (1) Make separate commits for logically separate changes.
38
39 Unless your patch is really trivial, you should not be sending
40 out a patch that was generated between your working tree and
41 your commit head. Instead, always make a commit with complete
42 commit message and generate a series of patches from your
43 repository. It is a good discipline.
44
45 Give an explanation for the change(s) that is detailed enough so
46 that people can judge if it is good thing to do, without reading
47 the actual patch text to determine how well the code does what
48 the explanation promises to do.
49
50 If your description starts to get too long, that's a sign that you
51 probably need to split up your commit to finer grained pieces.
52 That being said, patches which plainly describe the things that
53 help reviewers check the patch, and future maintainers understand
54 the code, are the most beautiful patches. Descriptions that summarize
55 the point in the subject well, and describe the motivation for the
56 change, the approach taken by the change, and if relevant how this
57 differs substantially from the prior version, are all good things
58 to have.
59
60 Make sure that you have tests for the bug you are fixing. See
61 t/README for guidance.
62
63 When adding a new feature, make sure that you have new tests to show
64 the feature triggers the new behavior when it should, and to show the
65 feature does not trigger when it shouldn't. After any code change, make
66 sure that the entire test suite passes.
67
68 If you have an account at GitHub (and you can get one for free to work
69 on open source projects), you can use their Travis CI integration to
70 test your changes on Linux, Mac (and hopefully soon Windows). See
71 GitHub-Travis CI hints section for details.
72
73 Do not forget to update the documentation to describe the updated
74 behavior and make sure that the resulting documentation set formats
75 well. It is currently a liberal mixture of US and UK English norms for
76 spelling and grammar, which is somewhat unfortunate. A huge patch that
77 touches the files all over the place only to correct the inconsistency
78 is not welcome, though. Potential clashes with other changes that can
79 result from such a patch are not worth it. We prefer to gradually
80 reconcile the inconsistencies in favor of US English, with small and
81 easily digestible patches, as a side effect of doing some other real
82 work in the vicinity (e.g. rewriting a paragraph for clarity, while
83 turning en_UK spelling to en_US). Obvious typographical fixes are much
84 more welcomed ("teh -> "the"), preferably submitted as independent
85 patches separate from other documentation changes.
86
87 Oh, another thing. We are picky about whitespaces. Make sure your
88 changes do not trigger errors with the sample pre-commit hook shipped
89 in templates/hooks--pre-commit. To help ensure this does not happen,
90 run "git diff --check" on your changes before you commit.
91
92
93 (2) Describe your changes well.
94
95 The first line of the commit message should be a short description (50
96 characters is the soft limit, see DISCUSSION in git-commit(1)), and
97 should skip the full stop. It is also conventional in most cases to
98 prefix the first line with "area: " where the area is a filename or
99 identifier for the general area of the code being modified, e.g.
100
101 . doc: clarify distinction between sign-off and pgp-signing
102 . githooks.txt: improve the intro section
103
104 If in doubt which identifier to use, run "git log --no-merges" on the
105 files you are modifying to see the current conventions.
106
107 It's customary to start the remainder of the first line after "area: "
108 with a lower-case letter. E.g. "doc: clarify...", not "doc:
109 Clarify...", or "githooks.txt: improve...", not "githooks.txt:
110 Improve...".
111
112 The body should provide a meaningful commit message, which:
113
114 . explains the problem the change tries to solve, i.e. what is wrong
115 with the current code without the change.
116
117 . justifies the way the change solves the problem, i.e. why the
118 result with the change is better.
119
120 . alternate solutions considered but discarded, if any.
121
122 Describe your changes in imperative mood, e.g. "make xyzzy do frotz"
123 instead of "[This patch] makes xyzzy do frotz" or "[I] changed xyzzy
124 to do frotz", as if you are giving orders to the codebase to change
125 its behavior. Try to make sure your explanation can be understood
126 without external resources. Instead of giving a URL to a mailing list
127 archive, summarize the relevant points of the discussion.
128
129 If you want to reference a previous commit in the history of a stable
130 branch, use the format "abbreviated sha1 (subject, date)",
131 with the subject enclosed in a pair of double-quotes, like this:
132
133 Commit f86a374 ("pack-bitmap.c: fix a memleak", 2015-03-30)
134 noticed that ...
135
136 The "Copy commit summary" command of gitk can be used to obtain this
137 format, or this invocation of "git show":
138
139 git show -s --date=short --pretty='format:%h ("%s", %ad)' <commit>
140
141 (3) Generate your patch using Git tools out of your commits.
142
143 Git based diff tools generate unidiff which is the preferred format.
144
145 You do not have to be afraid to use -M option to "git diff" or
146 "git format-patch", if your patch involves file renames. The
147 receiving end can handle them just fine.
148
149 Please make sure your patch does not add commented out debugging code,
150 or include any extra files which do not relate to what your patch
151 is trying to achieve. Make sure to review
152 your patch after generating it, to ensure accuracy. Before
153 sending out, please make sure it cleanly applies to the "master"
154 branch head. If you are preparing a work based on "next" branch,
155 that is fine, but please mark it as such.
156
157
158 (4) Sending your patches.
159
160 Learn to use format-patch and send-email if possible. These commands
161 are optimized for the workflow of sending patches, avoiding many ways
162 your existing e-mail client that is optimized for "multipart/*" mime
163 type e-mails to corrupt and render your patches unusable.
164
165 People on the Git mailing list need to be able to read and
166 comment on the changes you are submitting. It is important for
167 a developer to be able to "quote" your changes, using standard
168 e-mail tools, so that they may comment on specific portions of
169 your code. For this reason, each patch should be submitted
170 "inline" in a separate message.
171
172 Multiple related patches should be grouped into their own e-mail
173 thread to help readers find all parts of the series. To that end,
174 send them as replies to either an additional "cover letter" message
175 (see below), the first patch, or the respective preceding patch.
176
177 If your log message (including your name on the
178 Signed-off-by line) is not writable in ASCII, make sure that
179 you send off a message in the correct encoding.
180
181 WARNING: Be wary of your MUAs word-wrap
182 corrupting your patch. Do not cut-n-paste your patch; you can
183 lose tabs that way if you are not careful.
184
185 It is a common convention to prefix your subject line with
186 [PATCH]. This lets people easily distinguish patches from other
187 e-mail discussions. Use of additional markers after PATCH and
188 the closing bracket to mark the nature of the patch is also
189 encouraged. E.g. [PATCH/RFC] is often used when the patch is
190 not ready to be applied but it is for discussion, [PATCH v2],
191 [PATCH v3] etc. are often seen when you are sending an update to
192 what you have previously sent.
193
194 "git format-patch" command follows the best current practice to
195 format the body of an e-mail message. At the beginning of the
196 patch should come your commit message, ending with the
197 Signed-off-by: lines, and a line that consists of three dashes,
198 followed by the diffstat information and the patch itself. If
199 you are forwarding a patch from somebody else, optionally, at
200 the beginning of the e-mail message just before the commit
201 message starts, you can put a "From: " line to name that person.
202
203 You often want to add additional explanation about the patch,
204 other than the commit message itself. Place such "cover letter"
205 material between the three-dash line and the diffstat. For
206 patches requiring multiple iterations of review and discussion,
207 an explanation of changes between each iteration can be kept in
208 Git-notes and inserted automatically following the three-dash
209 line via `git format-patch --notes`.
210
211 Do not attach the patch as a MIME attachment, compressed or not.
212 Do not let your e-mail client send quoted-printable. Do not let
213 your e-mail client send format=flowed which would destroy
214 whitespaces in your patches. Many
215 popular e-mail applications will not always transmit a MIME
216 attachment as plain text, making it impossible to comment on
217 your code. A MIME attachment also takes a bit more time to
218 process. This does not decrease the likelihood of your
219 MIME-attached change being accepted, but it makes it more likely
220 that it will be postponed.
221
222 Exception: If your mailer is mangling patches then someone may ask
223 you to re-send them using MIME, that is OK.
224
225 Do not PGP sign your patch. Most likely, your maintainer or other people on the
226 list would not have your PGP key and would not bother obtaining it anyway.
227 Your patch is not judged by who you are; a good patch from an unknown origin
228 has a far better chance of being accepted than a patch from a known, respected
229 origin that is done poorly or does incorrect things.
230
231 If you really really really really want to do a PGP signed
232 patch, format it as "multipart/signed", not a text/plain message
233 that starts with '-----BEGIN PGP SIGNED MESSAGE-----'. That is
234 not a text/plain, it's something else.
235
236 Send your patch with "To:" set to the mailing list, with "cc:" listing
237 people who are involved in the area you are touching (the output from
238 "git blame $path" and "git shortlog --no-merges $path" would help to
239 identify them), to solicit comments and reviews.
240
241 After the list reached a consensus that it is a good idea to apply the
242 patch, re-send it with "To:" set to the maintainer [*1*] and "cc:" the
243 list [*2*] for inclusion.
244
245 Do not forget to add trailers such as "Acked-by:", "Reviewed-by:" and
246 "Tested-by:" lines as necessary to credit people who helped your
247 patch.
248
249 [Addresses]
250 *1* The current maintainer: gitster@pobox.com
251 *2* The mailing list: git@vger.kernel.org
252
253
254 (5) Certify your work by adding your "Signed-off-by: " line
255
256 To improve tracking of who did what, we've borrowed the
257 "sign-off" procedure from the Linux kernel project on patches
258 that are being emailed around. Although core Git is a lot
259 smaller project it is a good discipline to follow it.
260
261 The sign-off is a simple line at the end of the explanation for
262 the patch, which certifies that you wrote it or otherwise have
263 the right to pass it on as a open-source patch. The rules are
264 pretty simple: if you can certify the below D-C-O:
265
266 Developer's Certificate of Origin 1.1
267
268 By making a contribution to this project, I certify that:
269
270 (a) The contribution was created in whole or in part by me and I
271 have the right to submit it under the open source license
272 indicated in the file; or
273
274 (b) The contribution is based upon previous work that, to the best
275 of my knowledge, is covered under an appropriate open source
276 license and I have the right under that license to submit that
277 work with modifications, whether created in whole or in part
278 by me, under the same open source license (unless I am
279 permitted to submit under a different license), as indicated
280 in the file; or
281
282 (c) The contribution was provided directly to me by some other
283 person who certified (a), (b) or (c) and I have not modified
284 it.
285
286 (d) I understand and agree that this project and the contribution
287 are public and that a record of the contribution (including all
288 personal information I submit with it, including my sign-off) is
289 maintained indefinitely and may be redistributed consistent with
290 this project or the open source license(s) involved.
291
292 then you just add a line saying
293
294 Signed-off-by: Random J Developer <random@developer.example.org>
295
296 This line can be automatically added by Git if you run the git-commit
297 command with the -s option.
298
299 Notice that you can place your own Signed-off-by: line when
300 forwarding somebody else's patch with the above rules for
301 D-C-O. Indeed you are encouraged to do so. Do not forget to
302 place an in-body "From: " line at the beginning to properly attribute
303 the change to its true author (see (2) above).
304
305 Also notice that a real name is used in the Signed-off-by: line. Please
306 don't hide your real name.
307
308 If you like, you can put extra tags at the end:
309
310 1. "Reported-by:" is used to credit someone who found the bug that
311 the patch attempts to fix.
312 2. "Acked-by:" says that the person who is more familiar with the area
313 the patch attempts to modify liked the patch.
314 3. "Reviewed-by:", unlike the other tags, can only be offered by the
315 reviewer and means that she is completely satisfied that the patch
316 is ready for application. It is usually offered only after a
317 detailed review.
318 4. "Tested-by:" is used to indicate that the person applied the patch
319 and found it to have the desired effect.
320
321 You can also create your own tag or use one that's in common usage
322 such as "Thanks-to:", "Based-on-patch-by:", or "Mentored-by:".
323
324 ------------------------------------------------
325 Subsystems with dedicated maintainers
326
327 Some parts of the system have dedicated maintainers with their own
328 repositories.
329
330 - git-gui/ comes from git-gui project, maintained by Pat Thoyts:
331
332 git://repo.or.cz/git-gui.git
333
334 - gitk-git/ comes from Paul Mackerras's gitk project:
335
336 git://ozlabs.org/~paulus/gitk
337
338 - po/ comes from the localization coordinator, Jiang Xin:
339
340 https://github.com/git-l10n/git-po/
341
342 Patches to these parts should be based on their trees.
343
344 ------------------------------------------------
345 An ideal patch flow
346
347 Here is an ideal patch flow for this project the current maintainer
348 suggests to the contributors:
349
350 (0) You come up with an itch. You code it up.
351
352 (1) Send it to the list and cc people who may need to know about
353 the change.
354
355 The people who may need to know are the ones whose code you
356 are butchering. These people happen to be the ones who are
357 most likely to be knowledgeable enough to help you, but
358 they have no obligation to help you (i.e. you ask for help,
359 don't demand). "git log -p -- $area_you_are_modifying" would
360 help you find out who they are.
361
362 (2) You get comments and suggestions for improvements. You may
363 even get them in a "on top of your change" patch form.
364
365 (3) Polish, refine, and re-send to the list and the people who
366 spend their time to improve your patch. Go back to step (2).
367
368 (4) The list forms consensus that the last round of your patch is
369 good. Send it to the maintainer and cc the list.
370
371 (5) A topic branch is created with the patch and is merged to 'next',
372 and cooked further and eventually graduates to 'master'.
373
374 In any time between the (2)-(3) cycle, the maintainer may pick it up
375 from the list and queue it to 'pu', in order to make it easier for
376 people play with it without having to pick up and apply the patch to
377 their trees themselves.
378
379 ------------------------------------------------
380 Know the status of your patch after submission
381
382 * You can use Git itself to find out when your patch is merged in
383 master. 'git pull --rebase' will automatically skip already-applied
384 patches, and will let you know. This works only if you rebase on top
385 of the branch in which your patch has been merged (i.e. it will not
386 tell you if your patch is merged in pu if you rebase on top of
387 master).
388
389 * Read the Git mailing list, the maintainer regularly posts messages
390 entitled "What's cooking in git.git" and "What's in git.git" giving
391 the status of various proposed changes.
392
393 --------------------------------------------------
394 GitHub-Travis CI hints
395
396 With an account at GitHub (you can get one for free to work on open
397 source projects), you can use Travis CI to test your changes on Linux,
398 Mac (and hopefully soon Windows). You can find a successful example
399 test build here: https://travis-ci.org/git/git/builds/120473209
400
401 Follow these steps for the initial setup:
402
403 (1) Fork https://github.com/git/git to your GitHub account.
404 You can find detailed instructions how to fork here:
405 https://help.github.com/articles/fork-a-repo/
406
407 (2) Open the Travis CI website: https://travis-ci.org
408
409 (3) Press the "Sign in with GitHub" button.
410
411 (4) Grant Travis CI permissions to access your GitHub account.
412 You can find more information about the required permissions here:
413 https://docs.travis-ci.com/user/github-oauth-scopes
414
415 (5) Open your Travis CI profile page: https://travis-ci.org/profile
416
417 (6) Enable Travis CI builds for your Git fork.
418
419 After the initial setup, Travis CI will run whenever you push new changes
420 to your fork of Git on GitHub. You can monitor the test state of all your
421 branches here: https://travis-ci.org/<Your GitHub handle>/git/branches
422
423 If a branch did not pass all test cases then it is marked with a red
424 cross. In that case you can click on the failing Travis CI job and
425 scroll all the way down in the log. Find the line "<-- Click here to see
426 detailed test output!" and click on the triangle next to the log line
427 number to expand the detailed test output. Here is such a failing
428 example: https://travis-ci.org/git/git/jobs/122676187
429
430 Fix the problem and push your fix to your Git fork. This will trigger
431 a new Travis CI build to ensure all tests pass.
432
433
434 ------------------------------------------------
435 MUA specific hints
436
437 Some of patches I receive or pick up from the list share common
438 patterns of breakage. Please make sure your MUA is set up
439 properly not to corrupt whitespaces.
440
441 See the DISCUSSION section of git-format-patch(1) for hints on
442 checking your patch by mailing it to yourself and applying with
443 git-am(1).
444
445 While you are at it, check the resulting commit log message from
446 a trial run of applying the patch. If what is in the resulting
447 commit is not exactly what you would want to see, it is very
448 likely that your maintainer would end up hand editing the log
449 message when he applies your patch. Things like "Hi, this is my
450 first patch.\n", if you really want to put in the patch e-mail,
451 should come after the three-dash line that signals the end of the
452 commit message.
453
454
455 Pine
456 ----
457
458 (Johannes Schindelin)
459
460 I don't know how many people still use pine, but for those poor
461 souls it may be good to mention that the quell-flowed-text is
462 needed for recent versions.
463
464 ... the "no-strip-whitespace-before-send" option, too. AFAIK it
465 was introduced in 4.60.
466
467 (Linus Torvalds)
468
469 And 4.58 needs at least this.
470
471 ---
472 diff-tree 8326dd8350be64ac7fc805f6563a1d61ad10d32c (from e886a61f76edf5410573e92e38ce22974f9c40f1)
473 Author: Linus Torvalds <torvalds@g5.osdl.org>
474 Date: Mon Aug 15 17:23:51 2005 -0700
475
476 Fix pine whitespace-corruption bug
477
478 There's no excuse for unconditionally removing whitespace from
479 the pico buffers on close.
480
481 diff --git a/pico/pico.c b/pico/pico.c
482 --- a/pico/pico.c
483 +++ b/pico/pico.c
484 @@ -219,7 +219,9 @@ PICO *pm;
485 switch(pico_all_done){ /* prepare for/handle final events */
486 case COMP_EXIT : /* already confirmed */
487 packheader();
488 +#if 0
489 stripwhitespace();
490 +#endif
491 c |= COMP_EXIT;
492 break;
493
494
495 (Daniel Barkalow)
496
497 > A patch to SubmittingPatches, MUA specific help section for
498 > users of Pine 4.63 would be very much appreciated.
499
500 Ah, it looks like a recent version changed the default behavior to do the
501 right thing, and inverted the sense of the configuration option. (Either
502 that or Gentoo did it.) So you need to set the
503 "no-strip-whitespace-before-send" option, unless the option you have is
504 "strip-whitespace-before-send", in which case you should avoid checking
505 it.
506
507
508 Thunderbird, KMail, GMail
509 -------------------------
510
511 See the MUA-SPECIFIC HINTS section of git-format-patch(1).
512
513 Gnus
514 ----
515
516 '|' in the *Summary* buffer can be used to pipe the current
517 message to an external program, and this is a handy way to drive
518 "git am". However, if the message is MIME encoded, what is
519 piped into the program is the representation you see in your
520 *Article* buffer after unwrapping MIME. This is often not what
521 you would want for two reasons. It tends to screw up non ASCII
522 characters (most notably in people's names), and also
523 whitespaces (fatal in patches). Running 'C-u g' to display the
524 message in raw form before using '|' to run the pipe can work
525 this problem around.