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1 | My First Contribution to the Git Project |
2 | ======================================== | |
5ef811ac | 3 | :sectanchors: |
76644e32 | 4 | |
5ef811ac | 5 | [[summary]] |
76644e32 ES |
6 | == Summary |
7 | ||
8 | This is a tutorial demonstrating the end-to-end workflow of creating a change to | |
9 | the Git tree, sending it for review, and making changes based on comments. | |
10 | ||
5ef811ac | 11 | [[prerequisites]] |
76644e32 ES |
12 | === Prerequisites |
13 | ||
14 | This tutorial assumes you're already fairly familiar with using Git to manage | |
15 | source code. The Git workflow steps will largely remain unexplained. | |
16 | ||
5ef811ac | 17 | [[related-reading]] |
76644e32 ES |
18 | === Related Reading |
19 | ||
20 | This tutorial aims to summarize the following documents, but the reader may find | |
21 | useful additional context: | |
22 | ||
23 | - `Documentation/SubmittingPatches` | |
24 | - `Documentation/howto/new-command.txt` | |
25 | ||
4bb4fd42 ES |
26 | [[getting-help]] |
27 | === Getting Help | |
28 | ||
29 | If you get stuck, you can seek help in the following places. | |
30 | ||
a2dc4341 ES |
31 | ==== git@vger.kernel.org |
32 | ||
33 | This is the main Git project mailing list where code reviews, version | |
34 | announcements, design discussions, and more take place. Those interested in | |
35 | contributing are welcome to post questions here. The Git list requires | |
36 | plain-text-only emails and prefers inline and bottom-posting when replying to | |
37 | mail; you will be CC'd in all replies to you. Optionally, you can subscribe to | |
38 | the list by sending an email to majordomo@vger.kernel.org with "subscribe git" | |
39 | in the body. The https://lore.kernel.org/git[archive] of this mailing list is | |
40 | available to view in a browser. | |
41 | ||
4bb4fd42 ES |
42 | ==== https://groups.google.com/forum/#!forum/git-mentoring[git-mentoring@googlegroups.com] |
43 | ||
a2dc4341 ES |
44 | This mailing list is targeted to new contributors and was created as a place to |
45 | post questions and receive answers outside of the public eye of the main list. | |
46 | Veteran contributors who are especially interested in helping mentor newcomers | |
47 | are present on the list. In order to avoid search indexers, group membership is | |
48 | required to view messages; anyone can join and no approval is required. | |
4bb4fd42 | 49 | |
91d23470 | 50 | ==== https://web.libera.chat/#git-devel[#git-devel] on Libera Chat |
4bb4fd42 ES |
51 | |
52 | This IRC channel is for conversations between Git contributors. If someone is | |
53 | currently online and knows the answer to your question, you can receive help | |
54 | in real time. Otherwise, you can read the | |
55 | https://colabti.org/irclogger/irclogger_logs/git-devel[scrollback] to see | |
56 | whether someone answered you. IRC does not allow offline private messaging, so | |
57 | if you try to private message someone and then log out of IRC, they cannot | |
58 | respond to you. It's better to ask your questions in the channel so that you | |
59 | can be answered if you disconnect and so that others can learn from the | |
60 | conversation. | |
61 | ||
5ef811ac | 62 | [[getting-started]] |
76644e32 ES |
63 | == Getting Started |
64 | ||
5ef811ac | 65 | [[cloning]] |
76644e32 ES |
66 | === Clone the Git Repository |
67 | ||
68 | Git is mirrored in a number of locations. Clone the repository from one of them; | |
69 | https://git-scm.com/downloads suggests one of the best places to clone from is | |
70 | the mirror on GitHub. | |
71 | ||
72 | ---- | |
73 | $ git clone https://github.com/git/git git | |
2656fb16 | 74 | $ cd git |
76644e32 ES |
75 | ---- |
76 | ||
3ada78de ES |
77 | [[dependencies]] |
78 | === Installing Dependencies | |
79 | ||
80 | To build Git from source, you need to have a handful of dependencies installed | |
81 | on your system. For a hint of what's needed, you can take a look at | |
82 | `INSTALL`, paying close attention to the section about Git's dependencies on | |
83 | external programs and libraries. That document mentions a way to "test-drive" | |
84 | our freshly built Git without installing; that's the method we'll be using in | |
85 | this tutorial. | |
86 | ||
87 | Make sure that your environment has everything you need by building your brand | |
88 | new clone of Git from the above step: | |
89 | ||
90 | ---- | |
91 | $ make | |
92 | ---- | |
93 | ||
94 | NOTE: The Git build is parallelizable. `-j#` is not included above but you can | |
95 | use it as you prefer, here and elsewhere. | |
96 | ||
5ef811ac | 97 | [[identify-problem]] |
76644e32 ES |
98 | === Identify Problem to Solve |
99 | ||
100 | //// | |
101 | Use + to indicate fixed-width here; couldn't get ` to work nicely with the | |
102 | quotes around "Pony Saying 'Um, Hello'". | |
103 | //// | |
104 | In this tutorial, we will add a new command, +git psuh+, short for ``Pony Saying | |
105 | `Um, Hello''' - a feature which has gone unimplemented despite a high frequency | |
106 | of invocation during users' typical daily workflow. | |
107 | ||
108 | (We've seen some other effort in this space with the implementation of popular | |
109 | commands such as `sl`.) | |
110 | ||
5ef811ac | 111 | [[setup-workspace]] |
76644e32 ES |
112 | === Set Up Your Workspace |
113 | ||
114 | Let's start by making a development branch to work on our changes. Per | |
115 | `Documentation/SubmittingPatches`, since a brand new command is a new feature, | |
116 | it's fine to base your work on `master`. However, in the future for bugfixes, | |
117 | etc., you should check that document and base it on the appropriate branch. | |
118 | ||
119 | For the purposes of this document, we will base all our work on the `master` | |
120 | branch of the upstream project. Create the `psuh` branch you will use for | |
121 | development like so: | |
122 | ||
123 | ---- | |
124 | $ git checkout -b psuh origin/master | |
125 | ---- | |
126 | ||
127 | We'll make a number of commits here in order to demonstrate how to send a topic | |
128 | with multiple patches up for review simultaneously. | |
129 | ||
5ef811ac | 130 | [[code-it-up]] |
76644e32 ES |
131 | == Code It Up! |
132 | ||
133 | NOTE: A reference implementation can be found at | |
134 | https://github.com/nasamuffin/git/tree/psuh. | |
135 | ||
5ef811ac | 136 | [[add-new-command]] |
76644e32 ES |
137 | === Adding a New Command |
138 | ||
139 | Lots of the subcommands are written as builtins, which means they are | |
140 | implemented in C and compiled into the main `git` executable. Implementing the | |
141 | very simple `psuh` command as a built-in will demonstrate the structure of the | |
142 | codebase, the internal API, and the process of working together as a contributor | |
143 | with the reviewers and maintainer to integrate this change into the system. | |
144 | ||
145 | Built-in subcommands are typically implemented in a function named "cmd_" | |
146 | followed by the name of the subcommand, in a source file named after the | |
147 | subcommand and contained within `builtin/`. So it makes sense to implement your | |
148 | command in `builtin/psuh.c`. Create that file, and within it, write the entry | |
149 | point for your command in a function matching the style and signature: | |
150 | ||
151 | ---- | |
152 | int cmd_psuh(int argc, const char **argv, const char *prefix) | |
153 | ---- | |
154 | ||
155 | We'll also need to add the declaration of psuh; open up `builtin.h`, find the | |
24c68179 PS |
156 | declaration for `cmd_pull`, and add a new line for `psuh` immediately before it, |
157 | in order to keep the declarations alphabetically sorted: | |
76644e32 ES |
158 | |
159 | ---- | |
160 | int cmd_psuh(int argc, const char **argv, const char *prefix); | |
161 | ---- | |
162 | ||
163 | Be sure to `#include "builtin.h"` in your `psuh.c`. | |
164 | ||
165 | Go ahead and add some throwaway printf to that function. This is a decent | |
166 | starting point as we can now add build rules and register the command. | |
167 | ||
168 | NOTE: Your throwaway text, as well as much of the text you will be adding over | |
169 | the course of this tutorial, is user-facing. That means it needs to be | |
170 | localizable. Take a look at `po/README` under "Marking strings for translation". | |
171 | Throughout the tutorial, we will mark strings for translation as necessary; you | |
172 | should also do so when writing your user-facing commands in the future. | |
173 | ||
174 | ---- | |
175 | int cmd_psuh(int argc, const char **argv, const char *prefix) | |
176 | { | |
177 | printf(_("Pony saying hello goes here.\n")); | |
178 | return 0; | |
179 | } | |
180 | ---- | |
181 | ||
24c68179 | 182 | Let's try to build it. Open `Makefile`, find where `builtin/pull.o` is added |
76644e32 ES |
183 | to `BUILTIN_OBJS`, and add `builtin/psuh.o` in the same way next to it in |
184 | alphabetical order. Once you've done so, move to the top-level directory and | |
185 | build simply with `make`. Also add the `DEVELOPER=1` variable to turn on | |
186 | some additional warnings: | |
187 | ||
188 | ---- | |
189 | $ echo DEVELOPER=1 >config.mak | |
190 | $ make | |
191 | ---- | |
192 | ||
193 | NOTE: When you are developing the Git project, it's preferred that you use the | |
194 | `DEVELOPER` flag; if there's some reason it doesn't work for you, you can turn | |
195 | it off, but it's a good idea to mention the problem to the mailing list. | |
196 | ||
76644e32 ES |
197 | Great, now your new command builds happily on its own. But nobody invokes it. |
198 | Let's change that. | |
199 | ||
200 | The list of commands lives in `git.c`. We can register a new command by adding | |
201 | a `cmd_struct` to the `commands[]` array. `struct cmd_struct` takes a string | |
202 | with the command name, a function pointer to the command implementation, and a | |
203 | setup option flag. For now, let's keep mimicking `push`. Find the line where | |
204 | `cmd_push` is registered, copy it, and modify it for `cmd_psuh`, placing the new | |
24c68179 | 205 | line in alphabetical order (immediately before `cmd_pull`). |
76644e32 ES |
206 | |
207 | The options are documented in `builtin.h` under "Adding a new built-in." Since | |
208 | we hope to print some data about the user's current workspace context later, | |
209 | we need a Git directory, so choose `RUN_SETUP` as your only option. | |
210 | ||
211 | Go ahead and build again. You should see a clean build, so let's kick the tires | |
212 | and see if it works. There's a binary you can use to test with in the | |
213 | `bin-wrappers` directory. | |
214 | ||
215 | ---- | |
216 | $ ./bin-wrappers/git psuh | |
217 | ---- | |
218 | ||
219 | Check it out! You've got a command! Nice work! Let's commit this. | |
220 | ||
2656fb16 ES |
221 | `git status` reveals modified `Makefile`, `builtin.h`, and `git.c` as well as |
222 | untracked `builtin/psuh.c` and `git-psuh`. First, let's take care of the binary, | |
24c68179 | 223 | which should be ignored. Open `.gitignore` in your editor, find `/git-pull`, and |
2656fb16 ES |
224 | add an entry for your new command in alphabetical order: |
225 | ||
226 | ---- | |
227 | ... | |
228 | /git-prune-packed | |
229 | /git-psuh | |
230 | /git-pull | |
231 | /git-push | |
232 | /git-quiltimport | |
233 | /git-range-diff | |
234 | ... | |
235 | ---- | |
236 | ||
237 | Checking `git status` again should show that `git-psuh` has been removed from | |
238 | the untracked list and `.gitignore` has been added to the modified list. Now we | |
239 | can stage and commit: | |
240 | ||
76644e32 | 241 | ---- |
2656fb16 | 242 | $ git add Makefile builtin.h builtin/psuh.c git.c .gitignore |
76644e32 ES |
243 | $ git commit -s |
244 | ---- | |
245 | ||
246 | You will be presented with your editor in order to write a commit message. Start | |
247 | the commit with a 50-column or less subject line, including the name of the | |
248 | component you're working on, followed by a blank line (always required) and then | |
249 | the body of your commit message, which should provide the bulk of the context. | |
250 | Remember to be explicit and provide the "Why" of your change, especially if it | |
251 | couldn't easily be understood from your diff. When editing your commit message, | |
3abd4a67 | 252 | don't remove the `Signed-off-by` trailer which was added by `-s` above. |
76644e32 ES |
253 | |
254 | ---- | |
255 | psuh: add a built-in by popular demand | |
256 | ||
257 | Internal metrics indicate this is a command many users expect to be | |
258 | present. So here's an implementation to help drive customer | |
259 | satisfaction and engagement: a pony which doubtfully greets the user, | |
260 | or, a Pony Saying "Um, Hello" (PSUH). | |
261 | ||
262 | This commit message is intentionally formatted to 72 columns per line, | |
263 | starts with a single line as "commit message subject" that is written as | |
264 | if to command the codebase to do something (add this, teach a command | |
265 | that). The body of the message is designed to add information about the | |
266 | commit that is not readily deduced from reading the associated diff, | |
267 | such as answering the question "why?". | |
268 | ||
269 | Signed-off-by: A U Thor <author@example.com> | |
270 | ---- | |
271 | ||
272 | Go ahead and inspect your new commit with `git show`. "psuh:" indicates you | |
273 | have modified mainly the `psuh` command. The subject line gives readers an idea | |
274 | of what you've changed. The sign-off line (`-s`) indicates that you agree to | |
275 | the Developer's Certificate of Origin 1.1 (see the | |
276 | `Documentation/SubmittingPatches` +++[[dco]]+++ header). | |
277 | ||
278 | For the remainder of the tutorial, the subject line only will be listed for the | |
279 | sake of brevity. However, fully-fleshed example commit messages are available | |
280 | on the reference implementation linked at the top of this document. | |
281 | ||
5ef811ac | 282 | [[implementation]] |
76644e32 ES |
283 | === Implementation |
284 | ||
285 | It's probably useful to do at least something besides printing out a string. | |
286 | Let's start by having a look at everything we get. | |
287 | ||
2656fb16 ES |
288 | Modify your `cmd_psuh` implementation to dump the args you're passed, keeping |
289 | existing `printf()` calls in place: | |
76644e32 ES |
290 | |
291 | ---- | |
292 | int i; | |
293 | ||
294 | ... | |
295 | ||
296 | printf(Q_("Your args (there is %d):\n", | |
297 | "Your args (there are %d):\n", | |
298 | argc), | |
299 | argc); | |
300 | for (i = 0; i < argc; i++) | |
301 | printf("%d: %s\n", i, argv[i]); | |
302 | ||
303 | printf(_("Your current working directory:\n<top-level>%s%s\n"), | |
304 | prefix ? "/" : "", prefix ? prefix : ""); | |
305 | ||
306 | ---- | |
307 | ||
308 | Build and try it. As you may expect, there's pretty much just whatever we give | |
309 | on the command line, including the name of our command. (If `prefix` is empty | |
310 | for you, try `cd Documentation/ && ../bin-wrappers/git psuh`). That's not so | |
311 | helpful. So what other context can we get? | |
312 | ||
313 | Add a line to `#include "config.h"`. Then, add the following bits to the | |
314 | function body: | |
315 | ||
316 | ---- | |
317 | const char *cfg_name; | |
318 | ||
319 | ... | |
320 | ||
2656fb16 | 321 | git_config(git_default_config, NULL); |
9a53219f | 322 | if (git_config_get_string_tmp("user.name", &cfg_name) > 0) |
76644e32 ES |
323 | printf(_("No name is found in config\n")); |
324 | else | |
325 | printf(_("Your name: %s\n"), cfg_name); | |
326 | ---- | |
327 | ||
328 | `git_config()` will grab the configuration from config files known to Git and | |
9a53219f | 329 | apply standard precedence rules. `git_config_get_string_tmp()` will look up |
76644e32 ES |
330 | a specific key ("user.name") and give you the value. There are a number of |
331 | single-key lookup functions like this one; you can see them all (and more info | |
332 | about how to use `git_config()`) in `Documentation/technical/api-config.txt`. | |
333 | ||
334 | You should see that the name printed matches the one you see when you run: | |
335 | ||
336 | ---- | |
337 | $ git config --get user.name | |
338 | ---- | |
339 | ||
340 | Great! Now we know how to check for values in the Git config. Let's commit this | |
341 | too, so we don't lose our progress. | |
342 | ||
343 | ---- | |
344 | $ git add builtin/psuh.c | |
345 | $ git commit -sm "psuh: show parameters & config opts" | |
346 | ---- | |
347 | ||
348 | NOTE: Again, the above is for sake of brevity in this tutorial. In a real change | |
349 | you should not use `-m` but instead use the editor to write a meaningful | |
350 | message. | |
351 | ||
352 | Still, it'd be nice to know what the user's working context is like. Let's see | |
353 | if we can print the name of the user's current branch. We can mimic the | |
354 | `git status` implementation; the printer is located in `wt-status.c` and we can | |
355 | see that the branch is held in a `struct wt_status`. | |
356 | ||
357 | `wt_status_print()` gets invoked by `cmd_status()` in `builtin/commit.c`. | |
358 | Looking at that implementation we see the status config being populated like so: | |
359 | ||
360 | ---- | |
361 | status_init_config(&s, git_status_config); | |
362 | ---- | |
363 | ||
364 | But as we drill down, we can find that `status_init_config()` wraps a call | |
365 | to `git_config()`. Let's modify the code we wrote in the previous commit. | |
366 | ||
367 | Be sure to include the header to allow you to use `struct wt_status`: | |
368 | ---- | |
369 | #include "wt-status.h" | |
370 | ---- | |
371 | ||
372 | Then modify your `cmd_psuh` implementation to declare your `struct wt_status`, | |
373 | prepare it, and print its contents: | |
374 | ||
375 | ---- | |
376 | struct wt_status status; | |
377 | ||
378 | ... | |
379 | ||
380 | wt_status_prepare(the_repository, &status); | |
381 | git_config(git_default_config, &status); | |
382 | ||
383 | ... | |
384 | ||
385 | printf(_("Your current branch: %s\n"), status.branch); | |
386 | ---- | |
387 | ||
388 | Run it again. Check it out - here's the (verbose) name of your current branch! | |
389 | ||
390 | Let's commit this as well. | |
391 | ||
392 | ---- | |
2656fb16 | 393 | $ git add builtin/psuh.c |
76644e32 ES |
394 | $ git commit -sm "psuh: print the current branch" |
395 | ---- | |
396 | ||
397 | Now let's see if we can get some info about a specific commit. | |
398 | ||
399 | Luckily, there are some helpers for us here. `commit.h` has a function called | |
400 | `lookup_commit_reference_by_name` to which we can simply provide a hardcoded | |
401 | string; `pretty.h` has an extremely handy `pp_commit_easy()` call which doesn't | |
402 | require a full format object to be passed. | |
403 | ||
404 | Add the following includes: | |
405 | ||
406 | ---- | |
407 | #include "commit.h" | |
408 | #include "pretty.h" | |
409 | ---- | |
410 | ||
411 | Then, add the following lines within your implementation of `cmd_psuh()` near | |
412 | the declarations and the logic, respectively. | |
413 | ||
414 | ---- | |
415 | struct commit *c = NULL; | |
416 | struct strbuf commitline = STRBUF_INIT; | |
417 | ||
418 | ... | |
419 | ||
420 | c = lookup_commit_reference_by_name("origin/master"); | |
421 | ||
422 | if (c != NULL) { | |
423 | pp_commit_easy(CMIT_FMT_ONELINE, c, &commitline); | |
424 | printf(_("Current commit: %s\n"), commitline.buf); | |
425 | } | |
426 | ---- | |
427 | ||
428 | The `struct strbuf` provides some safety belts to your basic `char*`, one of | |
429 | which is a length member to prevent buffer overruns. It needs to be initialized | |
430 | nicely with `STRBUF_INIT`. Keep it in mind when you need to pass around `char*`. | |
431 | ||
432 | `lookup_commit_reference_by_name` resolves the name you pass it, so you can play | |
433 | with the value there and see what kind of things you can come up with. | |
434 | ||
435 | `pp_commit_easy` is a convenience wrapper in `pretty.h` that takes a single | |
436 | format enum shorthand, rather than an entire format struct. It then | |
437 | pretty-prints the commit according to that shorthand. These are similar to the | |
438 | formats available with `--pretty=FOO` in many Git commands. | |
439 | ||
440 | Build it and run, and if you're using the same name in the example, you should | |
441 | see the subject line of the most recent commit in `origin/master` that you know | |
442 | about. Neat! Let's commit that as well. | |
443 | ||
444 | ---- | |
2656fb16 | 445 | $ git add builtin/psuh.c |
76644e32 ES |
446 | $ git commit -sm "psuh: display the top of origin/master" |
447 | ---- | |
448 | ||
5ef811ac | 449 | [[add-documentation]] |
76644e32 ES |
450 | === Adding Documentation |
451 | ||
452 | Awesome! You've got a fantastic new command that you're ready to share with the | |
453 | community. But hang on just a minute - this isn't very user-friendly. Run the | |
454 | following: | |
455 | ||
456 | ---- | |
457 | $ ./bin-wrappers/git help psuh | |
458 | ---- | |
459 | ||
460 | Your new command is undocumented! Let's fix that. | |
461 | ||
462 | Take a look at `Documentation/git-*.txt`. These are the manpages for the | |
463 | subcommands that Git knows about. You can open these up and take a look to get | |
464 | acquainted with the format, but then go ahead and make a new file | |
465 | `Documentation/git-psuh.txt`. Like with most of the documentation in the Git | |
466 | project, help pages are written with AsciiDoc (see CodingGuidelines, "Writing | |
467 | Documentation" section). Use the following template to fill out your own | |
468 | manpage: | |
469 | ||
470 | // Surprisingly difficult to embed AsciiDoc source within AsciiDoc. | |
471 | [listing] | |
472 | .... | |
473 | git-psuh(1) | |
474 | =========== | |
475 | ||
476 | NAME | |
477 | ---- | |
478 | git-psuh - Delight users' typo with a shy horse | |
479 | ||
480 | ||
481 | SYNOPSIS | |
482 | -------- | |
483 | [verse] | |
b37e0ec3 | 484 | 'git-psuh [<arg>...]' |
76644e32 ES |
485 | |
486 | DESCRIPTION | |
487 | ----------- | |
488 | ... | |
489 | ||
490 | OPTIONS[[OPTIONS]] | |
491 | ------------------ | |
492 | ... | |
493 | ||
494 | OUTPUT | |
495 | ------ | |
496 | ... | |
497 | ||
76644e32 ES |
498 | GIT |
499 | --- | |
500 | Part of the linkgit:git[1] suite | |
501 | .... | |
502 | ||
503 | The most important pieces of this to note are the file header, underlined by =, | |
504 | the NAME section, and the SYNOPSIS, which would normally contain the grammar if | |
505 | your command took arguments. Try to use well-established manpage headers so your | |
506 | documentation is consistent with other Git and UNIX manpages; this makes life | |
507 | easier for your user, who can skip to the section they know contains the | |
508 | information they need. | |
509 | ||
f5bcde6c ES |
510 | NOTE: Before trying to build the docs, make sure you have the package `asciidoc` |
511 | installed. | |
512 | ||
76644e32 ES |
513 | Now that you've written your manpage, you'll need to build it explicitly. We |
514 | convert your AsciiDoc to troff which is man-readable like so: | |
515 | ||
516 | ---- | |
517 | $ make all doc | |
518 | $ man Documentation/git-psuh.1 | |
519 | ---- | |
520 | ||
521 | or | |
522 | ||
523 | ---- | |
524 | $ make -C Documentation/ git-psuh.1 | |
525 | $ man Documentation/git-psuh.1 | |
526 | ---- | |
527 | ||
76644e32 ES |
528 | While this isn't as satisfying as running through `git help`, you can at least |
529 | check that your help page looks right. | |
530 | ||
531 | You can also check that the documentation coverage is good (that is, the project | |
532 | sees that your command has been implemented as well as documented) by running | |
533 | `make check-docs` from the top-level. | |
534 | ||
535 | Go ahead and commit your new documentation change. | |
536 | ||
5ef811ac | 537 | [[add-usage]] |
76644e32 ES |
538 | === Adding Usage Text |
539 | ||
540 | Try and run `./bin-wrappers/git psuh -h`. Your command should crash at the end. | |
541 | That's because `-h` is a special case which your command should handle by | |
542 | printing usage. | |
543 | ||
544 | Take a look at `Documentation/technical/api-parse-options.txt`. This is a handy | |
545 | tool for pulling out options you need to be able to handle, and it takes a | |
546 | usage string. | |
547 | ||
b37e0ec3 CC |
548 | In order to use it, we'll need to prepare a NULL-terminated array of usage |
549 | strings and a `builtin_psuh_options` array. | |
76644e32 | 550 | |
b37e0ec3 CC |
551 | Add a line to `#include "parse-options.h"`. |
552 | ||
553 | At global scope, add your array of usage strings: | |
76644e32 ES |
554 | |
555 | ---- | |
556 | static const char * const psuh_usage[] = { | |
b37e0ec3 | 557 | N_("git psuh [<arg>...]"), |
76644e32 ES |
558 | NULL, |
559 | }; | |
560 | ---- | |
561 | ||
562 | Then, within your `cmd_psuh()` implementation, we can declare and populate our | |
563 | `option` struct. Ours is pretty boring but you can add more to it if you want to | |
564 | explore `parse_options()` in more detail: | |
565 | ||
566 | ---- | |
567 | struct option options[] = { | |
568 | OPT_END() | |
569 | }; | |
570 | ---- | |
571 | ||
572 | Finally, before you print your args and prefix, add the call to | |
573 | `parse-options()`: | |
574 | ||
575 | ---- | |
576 | argc = parse_options(argc, argv, prefix, options, psuh_usage, 0); | |
577 | ---- | |
578 | ||
579 | This call will modify your `argv` parameter. It will strip the options you | |
580 | specified in `options` from `argv` and the locations pointed to from `options` | |
581 | entries will be updated. Be sure to replace your `argc` with the result from | |
582 | `parse_options()`, or you will be confused if you try to parse `argv` later. | |
583 | ||
584 | It's worth noting the special argument `--`. As you may be aware, many Unix | |
585 | commands use `--` to indicate "end of named parameters" - all parameters after | |
586 | the `--` are interpreted merely as positional arguments. (This can be handy if | |
587 | you want to pass as a parameter something which would usually be interpreted as | |
588 | a flag.) `parse_options()` will terminate parsing when it reaches `--` and give | |
589 | you the rest of the options afterwards, untouched. | |
590 | ||
4ed55629 ES |
591 | Now that you have a usage hint, you can teach Git how to show it in the general |
592 | command list shown by `git help git` or `git help -a`, which is generated from | |
593 | `command-list.txt`. Find the line for 'git-pull' so you can add your 'git-psuh' | |
594 | line above it in alphabetical order. Now, we can add some attributes about the | |
595 | command which impacts where it shows up in the aforementioned help commands. The | |
596 | top of `command-list.txt` shares some information about what each attribute | |
597 | means; in those help pages, the commands are sorted according to these | |
598 | attributes. `git psuh` is user-facing, or porcelain - so we will mark it as | |
599 | "mainporcelain". For "mainporcelain" commands, the comments at the top of | |
600 | `command-list.txt` indicate we can also optionally add an attribute from another | |
601 | list; since `git psuh` shows some information about the user's workspace but | |
602 | doesn't modify anything, let's mark it as "info". Make sure to keep your | |
603 | attributes in the same style as the rest of `command-list.txt` using spaces to | |
604 | align and delineate them: | |
605 | ||
606 | ---- | |
607 | git-prune-packed plumbingmanipulators | |
608 | git-psuh mainporcelain info | |
609 | git-pull mainporcelain remote | |
610 | git-push mainporcelain remote | |
611 | ---- | |
612 | ||
76644e32 ES |
613 | Build again. Now, when you run with `-h`, you should see your usage printed and |
614 | your command terminated before anything else interesting happens. Great! | |
615 | ||
616 | Go ahead and commit this one, too. | |
617 | ||
5ef811ac | 618 | [[testing]] |
76644e32 ES |
619 | == Testing |
620 | ||
621 | It's important to test your code - even for a little toy command like this one. | |
622 | Moreover, your patch won't be accepted into the Git tree without tests. Your | |
623 | tests should: | |
624 | ||
625 | * Illustrate the current behavior of the feature | |
626 | * Prove the current behavior matches the expected behavior | |
627 | * Ensure the externally-visible behavior isn't broken in later changes | |
628 | ||
629 | So let's write some tests. | |
630 | ||
631 | Related reading: `t/README` | |
632 | ||
5ef811ac | 633 | [[overview-test-structure]] |
76644e32 ES |
634 | === Overview of Testing Structure |
635 | ||
636 | The tests in Git live in `t/` and are named with a 4-digit decimal number using | |
637 | the schema shown in the Naming Tests section of `t/README`. | |
638 | ||
5ef811ac | 639 | [[write-new-test]] |
76644e32 ES |
640 | === Writing Your Test |
641 | ||
642 | Since this a toy command, let's go ahead and name the test with t9999. However, | |
643 | as many of the family/subcmd combinations are full, best practice seems to be | |
644 | to find a command close enough to the one you've added and share its naming | |
645 | space. | |
646 | ||
647 | Create a new file `t/t9999-psuh-tutorial.sh`. Begin with the header as so (see | |
648 | "Writing Tests" and "Source 'test-lib.sh'" in `t/README`): | |
649 | ||
650 | ---- | |
651 | #!/bin/sh | |
652 | ||
653 | test_description='git-psuh test | |
654 | ||
655 | This test runs git-psuh and makes sure it does not crash.' | |
656 | ||
657 | . ./test-lib.sh | |
658 | ---- | |
659 | ||
660 | Tests are framed inside of a `test_expect_success` in order to output TAP | |
661 | formatted results. Let's make sure that `git psuh` doesn't exit poorly and does | |
662 | mention the right animal somewhere: | |
663 | ||
664 | ---- | |
665 | test_expect_success 'runs correctly with no args and good output' ' | |
666 | git psuh >actual && | |
d162b25f | 667 | grep Pony actual |
76644e32 ES |
668 | ' |
669 | ---- | |
670 | ||
671 | Indicate that you've run everything you wanted by adding the following at the | |
672 | bottom of your script: | |
673 | ||
674 | ---- | |
675 | test_done | |
676 | ---- | |
677 | ||
678 | Make sure you mark your test script executable: | |
679 | ||
680 | ---- | |
681 | $ chmod +x t/t9999-psuh-tutorial.sh | |
682 | ---- | |
683 | ||
684 | You can get an idea of whether you created your new test script successfully | |
685 | by running `make -C t test-lint`, which will check for things like test number | |
686 | uniqueness, executable bit, and so on. | |
687 | ||
5ef811ac | 688 | [[local-test]] |
76644e32 ES |
689 | === Running Locally |
690 | ||
691 | Let's try and run locally: | |
692 | ||
693 | ---- | |
694 | $ make | |
695 | $ cd t/ && prove t9999-psuh-tutorial.sh | |
696 | ---- | |
697 | ||
698 | You can run the full test suite and ensure `git-psuh` didn't break anything: | |
699 | ||
700 | ---- | |
701 | $ cd t/ | |
702 | $ prove -j$(nproc) --shuffle t[0-9]*.sh | |
703 | ---- | |
704 | ||
705 | NOTE: You can also do this with `make test` or use any testing harness which can | |
706 | speak TAP. `prove` can run concurrently. `shuffle` randomizes the order the | |
707 | tests are run in, which makes them resilient against unwanted inter-test | |
708 | dependencies. `prove` also makes the output nicer. | |
709 | ||
710 | Go ahead and commit this change, as well. | |
711 | ||
5ef811ac | 712 | [[ready-to-share]] |
489ef3ba | 713 | == Getting Ready to Share: Anatomy of a Patch Series |
76644e32 ES |
714 | |
715 | You may have noticed already that the Git project performs its code reviews via | |
716 | emailed patches, which are then applied by the maintainer when they are ready | |
489ef3ba | 717 | and approved by the community. The Git project does not accept contributions from |
76644e32 | 718 | pull requests, and the patches emailed for review need to be formatted a |
489ef3ba PB |
719 | specific way. |
720 | ||
721 | :patch-series: https://lore.kernel.org/git/pull.1218.git.git.1645209647.gitgitgadget@gmail.com/ | |
722 | :lore: https://lore.kernel.org/git/ | |
723 | ||
724 | Before taking a look at how to convert your commits into emailed patches, | |
725 | let's analyze what the end result, a "patch series", looks like. Here is an | |
726 | {patch-series}[example] of the summary view for a patch series on the web interface of | |
727 | the {lore}[Git mailing list archive]: | |
728 | ||
729 | ---- | |
730 | 2022-02-18 18:40 [PATCH 0/3] libify reflog John Cai via GitGitGadget | |
731 | 2022-02-18 18:40 ` [PATCH 1/3] reflog: libify delete reflog function and helpers John Cai via GitGitGadget | |
732 | 2022-02-18 19:10 ` Ævar Arnfjörð Bjarmason [this message] | |
733 | 2022-02-18 19:39 ` Taylor Blau | |
734 | 2022-02-18 19:48 ` Ævar Arnfjörð Bjarmason | |
735 | 2022-02-18 19:35 ` Taylor Blau | |
736 | 2022-02-21 1:43 ` John Cai | |
737 | 2022-02-21 1:50 ` Taylor Blau | |
738 | 2022-02-23 19:50 ` John Cai | |
c5353c45 | 739 | 2022-02-18 20:00 ` // other replies elided |
489ef3ba PB |
740 | 2022-02-18 18:40 ` [PATCH 2/3] reflog: call reflog_delete from reflog.c John Cai via GitGitGadget |
741 | 2022-02-18 19:15 ` Ævar Arnfjörð Bjarmason | |
742 | 2022-02-18 20:26 ` Junio C Hamano | |
743 | 2022-02-18 18:40 ` [PATCH 3/3] stash: call reflog_delete from reflog.c John Cai via GitGitGadget | |
744 | 2022-02-18 19:20 ` Ævar Arnfjörð Bjarmason | |
745 | 2022-02-19 0:21 ` Taylor Blau | |
746 | 2022-02-22 2:36 ` John Cai | |
747 | 2022-02-22 10:51 ` Ævar Arnfjörð Bjarmason | |
748 | 2022-02-18 19:29 ` [PATCH 0/3] libify reflog Ævar Arnfjörð Bjarmason | |
749 | 2022-02-22 18:30 ` [PATCH v2 0/3] libify reflog John Cai via GitGitGadget | |
750 | 2022-02-22 18:30 ` [PATCH v2 1/3] stash: add test to ensure reflog --rewrite --updatref behavior John Cai via GitGitGadget | |
751 | 2022-02-23 8:54 ` Ævar Arnfjörð Bjarmason | |
752 | 2022-02-23 21:27 ` Junio C Hamano | |
753 | // continued | |
754 | ---- | |
755 | ||
756 | We can note a few things: | |
757 | ||
758 | - Each commit is sent as a separate email, with the commit message title as | |
759 | subject, prefixed with "[PATCH _i_/_n_]" for the _i_-th commit of an | |
760 | _n_-commit series. | |
761 | - Each patch is sent as a reply to an introductory email called the _cover | |
762 | letter_ of the series, prefixed "[PATCH 0/_n_]". | |
afc8c925 PB |
763 | - Subsequent iterations of the patch series are labelled "PATCH v2", "PATCH |
764 | v3", etc. in place of "PATCH". For example, "[PATCH v2 1/3]" would be the first of | |
765 | three patches in the second iteration. Each iteration is sent with a new cover | |
766 | letter (like "[PATCH v2 0/3]" above), itself a reply to the cover letter of the | |
767 | previous iteration (more on that below). | |
768 | ||
769 | NOTE: A single-patch topic is sent with "[PATCH]", "[PATCH v2]", etc. without | |
770 | _i_/_n_ numbering (in the above thread overview, no single-patch topic appears, | |
771 | though). | |
772 | ||
773 | [[cover-letter]] | |
774 | === The cover letter | |
775 | ||
776 | In addition to an email per patch, the Git community also expects your patches | |
777 | to come with a cover letter. This is an important component of change | |
778 | submission as it explains to the community from a high level what you're trying | |
779 | to do, and why, in a way that's more apparent than just looking at your | |
780 | patches. | |
781 | ||
782 | The title of your cover letter should be something which succinctly covers the | |
783 | purpose of your entire topic branch. It's often in the imperative mood, just | |
784 | like our commit message titles. Here is how we'll title our series: | |
785 | ||
786 | --- | |
787 | Add the 'psuh' command | |
788 | --- | |
789 | ||
790 | The body of the cover letter is used to give additional context to reviewers. | |
791 | Be sure to explain anything your patches don't make clear on their own, but | |
792 | remember that since the cover letter is not recorded in the commit history, | |
793 | anything that might be useful to future readers of the repository's history | |
794 | should also be in your commit messages. | |
795 | ||
796 | Here's an example body for `psuh`: | |
797 | ||
798 | ---- | |
799 | Our internal metrics indicate widespread interest in the command | |
800 | git-psuh - that is, many users are trying to use it, but finding it is | |
801 | unavailable, using some unknown workaround instead. | |
802 | ||
803 | The following handful of patches add the psuh command and implement some | |
804 | handy features on top of it. | |
805 | ||
806 | This patchset is part of the MyFirstContribution tutorial and should not | |
807 | be merged. | |
808 | ---- | |
489ef3ba PB |
809 | |
810 | At this point the tutorial diverges, in order to demonstrate two | |
76644e32 ES |
811 | different methods of formatting your patchset and getting it reviewed. |
812 | ||
813 | The first method to be covered is GitGitGadget, which is useful for those | |
814 | already familiar with GitHub's common pull request workflow. This method | |
815 | requires a GitHub account. | |
816 | ||
817 | The second method to be covered is `git send-email`, which can give slightly | |
818 | more fine-grained control over the emails to be sent. This method requires some | |
819 | setup which can change depending on your system and will not be covered in this | |
820 | tutorial. | |
821 | ||
822 | Regardless of which method you choose, your engagement with reviewers will be | |
823 | the same; the review process will be covered after the sections on GitGitGadget | |
824 | and `git send-email`. | |
825 | ||
5ef811ac | 826 | [[howto-ggg]] |
76644e32 ES |
827 | == Sending Patches via GitGitGadget |
828 | ||
829 | One option for sending patches is to follow a typical pull request workflow and | |
830 | send your patches out via GitGitGadget. GitGitGadget is a tool created by | |
831 | Johannes Schindelin to make life as a Git contributor easier for those used to | |
832 | the GitHub PR workflow. It allows contributors to open pull requests against its | |
833 | mirror of the Git project, and does some magic to turn the PR into a set of | |
834 | emails and send them out for you. It also runs the Git continuous integration | |
835 | suite for you. It's documented at http://gitgitgadget.github.io. | |
836 | ||
5ef811ac | 837 | [[create-fork]] |
76644e32 ES |
838 | === Forking `git/git` on GitHub |
839 | ||
840 | Before you can send your patch off to be reviewed using GitGitGadget, you will | |
841 | need to fork the Git project and upload your changes. First thing - make sure | |
842 | you have a GitHub account. | |
843 | ||
844 | Head to the https://github.com/git/git[GitHub mirror] and look for the Fork | |
845 | button. Place your fork wherever you deem appropriate and create it. | |
846 | ||
5ef811ac | 847 | [[upload-to-fork]] |
76644e32 ES |
848 | === Uploading to Your Own Fork |
849 | ||
850 | To upload your branch to your own fork, you'll need to add the new fork as a | |
851 | remote. You can use `git remote -v` to show the remotes you have added already. | |
852 | From your new fork's page on GitHub, you can press "Clone or download" to get | |
853 | the URL; then you need to run the following to add, replacing your own URL and | |
854 | remote name for the examples provided: | |
855 | ||
856 | ---- | |
857 | $ git remote add remotename git@github.com:remotename/git.git | |
858 | ---- | |
859 | ||
860 | or to use the HTTPS URL: | |
861 | ||
862 | ---- | |
863 | $ git remote add remotename https://github.com/remotename/git/.git | |
864 | ---- | |
865 | ||
866 | Run `git remote -v` again and you should see the new remote showing up. | |
867 | `git fetch remotename` (with the real name of your remote replaced) in order to | |
868 | get ready to push. | |
869 | ||
870 | Next, double-check that you've been doing all your development in a new branch | |
871 | by running `git branch`. If you didn't, now is a good time to move your new | |
872 | commits to their own branch. | |
873 | ||
874 | As mentioned briefly at the beginning of this document, we are basing our work | |
875 | on `master`, so go ahead and update as shown below, or using your preferred | |
876 | workflow. | |
877 | ||
878 | ---- | |
879 | $ git checkout master | |
880 | $ git pull -r | |
881 | $ git rebase master psuh | |
882 | ---- | |
883 | ||
884 | Finally, you're ready to push your new topic branch! (Due to our branch and | |
885 | command name choices, be careful when you type the command below.) | |
886 | ||
887 | ---- | |
888 | $ git push remotename psuh | |
889 | ---- | |
890 | ||
891 | Now you should be able to go and check out your newly created branch on GitHub. | |
892 | ||
5ef811ac | 893 | [[send-pr-ggg]] |
76644e32 ES |
894 | === Sending a PR to GitGitGadget |
895 | ||
896 | In order to have your code tested and formatted for review, you need to start by | |
897 | opening a Pull Request against `gitgitgadget/git`. Head to | |
898 | https://github.com/gitgitgadget/git and open a PR either with the "New pull | |
899 | request" button or the convenient "Compare & pull request" button that may | |
900 | appear with the name of your newly pushed branch. | |
901 | ||
c2cd4b59 PB |
902 | Review the PR's title and description, as they're used by GitGitGadget |
903 | respectively as the subject and body of the cover letter for your change. Refer | |
904 | to <<cover-letter,"The cover letter">> above for advice on how to title your | |
905 | submission and what content to include in the description. | |
906 | ||
4ec50080 PB |
907 | NOTE: For single-patch contributions, your commit message should already be |
908 | meaningful and explain at a high level the purpose (what is happening and why) | |
909 | of your patch, so you usually do not need any additional context. In that case, | |
910 | remove the PR description that GitHub automatically generates from your commit | |
911 | message (your PR description should be empty). If you do need to supply even | |
912 | more context, you can do so in that space and it will be appended to the email | |
913 | that GitGitGadget will send, between the three-dash line and the diffstat | |
914 | (see <<single-patch,Bonus Chapter: One-Patch Changes>> for how this looks once | |
915 | submitted). | |
916 | ||
c2cd4b59 | 917 | When you're happy, submit your pull request. |
76644e32 | 918 | |
5ef811ac | 919 | [[run-ci-ggg]] |
76644e32 ES |
920 | === Running CI and Getting Ready to Send |
921 | ||
922 | If it's your first time using GitGitGadget (which is likely, as you're using | |
923 | this tutorial) then someone will need to give you permission to use the tool. | |
924 | As mentioned in the GitGitGadget documentation, you just need someone who | |
925 | already uses it to comment on your PR with `/allow <username>`. GitGitGadget | |
926 | will automatically run your PRs through the CI even without the permission given | |
927 | but you will not be able to `/submit` your changes until someone allows you to | |
928 | use the tool. | |
929 | ||
3c8d754c ES |
930 | NOTE: You can typically find someone who can `/allow` you on GitGitGadget by |
931 | either examining recent pull requests where someone has been granted `/allow` | |
932 | (https://github.com/gitgitgadget/git/pulls?utf8=%E2%9C%93&q=is%3Apr+is%3Aopen+%22%2Fallow%22[Search: | |
933 | is:pr is:open "/allow"]), in which case both the author and the person who | |
934 | granted the `/allow` can now `/allow` you, or by inquiring on the | |
91d23470 | 935 | https://web.libera.chat/#git-devel[#git-devel] IRC channel on Libera Chat |
3c8d754c ES |
936 | linking your pull request and asking for someone to `/allow` you. |
937 | ||
76644e32 ES |
938 | If the CI fails, you can update your changes with `git rebase -i` and push your |
939 | branch again: | |
940 | ||
941 | ---- | |
942 | $ git push -f remotename psuh | |
943 | ---- | |
944 | ||
945 | In fact, you should continue to make changes this way up until the point when | |
946 | your patch is accepted into `next`. | |
947 | ||
948 | //// | |
949 | TODO https://github.com/gitgitgadget/gitgitgadget/issues/83 | |
950 | It'd be nice to be able to verify that the patch looks good before sending it | |
951 | to everyone on Git mailing list. | |
5ef811ac | 952 | [[check-work-ggg]] |
76644e32 ES |
953 | === Check Your Work |
954 | //// | |
955 | ||
5ef811ac | 956 | [[send-mail-ggg]] |
76644e32 ES |
957 | === Sending Your Patches |
958 | ||
959 | Now that your CI is passing and someone has granted you permission to use | |
960 | GitGitGadget with the `/allow` command, sending out for review is as simple as | |
961 | commenting on your PR with `/submit`. | |
962 | ||
5ef811ac | 963 | [[responding-ggg]] |
76644e32 ES |
964 | === Updating With Comments |
965 | ||
966 | Skip ahead to <<reviewing,Responding to Reviews>> for information on how to | |
967 | reply to review comments you will receive on the mailing list. | |
968 | ||
969 | Once you have your branch again in the shape you want following all review | |
970 | comments, you can submit again: | |
971 | ||
972 | ---- | |
973 | $ git push -f remotename psuh | |
974 | ---- | |
975 | ||
976 | Next, go look at your pull request against GitGitGadget; you should see the CI | |
977 | has been kicked off again. Now while the CI is running is a good time for you | |
978 | to modify your description at the top of the pull request thread; it will be | |
979 | used again as the cover letter. You should use this space to describe what | |
980 | has changed since your previous version, so that your reviewers have some idea | |
981 | of what they're looking at. When the CI is done running, you can comment once | |
982 | more with `/submit` - GitGitGadget will automatically add a v2 mark to your | |
983 | changes. | |
984 | ||
5ef811ac | 985 | [[howto-git-send-email]] |
76644e32 ES |
986 | == Sending Patches with `git send-email` |
987 | ||
988 | If you don't want to use GitGitGadget, you can also use Git itself to mail your | |
989 | patches. Some benefits of using Git this way include finer grained control of | |
990 | subject line (for example, being able to use the tag [RFC PATCH] in the subject) | |
991 | and being able to send a ``dry run'' mail to yourself to ensure it all looks | |
992 | good before going out to the list. | |
993 | ||
5ef811ac | 994 | [[setup-git-send-email]] |
76644e32 ES |
995 | === Prerequisite: Setting Up `git send-email` |
996 | ||
997 | Configuration for `send-email` can vary based on your operating system and email | |
998 | provider, and so will not be covered in this tutorial, beyond stating that in | |
999 | many distributions of Linux, `git-send-email` is not packaged alongside the | |
1000 | typical `git` install. You may need to install this additional package; there | |
1001 | are a number of resources online to help you do so. You will also need to | |
1002 | determine the right way to configure it to use your SMTP server; again, as this | |
1003 | configuration can change significantly based on your system and email setup, it | |
1004 | is out of scope for the context of this tutorial. | |
1005 | ||
5ef811ac | 1006 | [[format-patch]] |
76644e32 ES |
1007 | === Preparing Initial Patchset |
1008 | ||
1009 | Sending emails with Git is a two-part process; before you can prepare the emails | |
1010 | themselves, you'll need to prepare the patches. Luckily, this is pretty simple: | |
1011 | ||
1012 | ---- | |
0b45a41d JH |
1013 | $ git format-patch --cover-letter -o psuh/ --base=auto psuh@{u}..psuh |
1014 | ---- | |
1015 | ||
1016 | . The `--cover-letter` option tells `format-patch` to create a | |
1017 | cover letter template for you. You will need to fill in the | |
1018 | template before you're ready to send - but for now, the template | |
1019 | will be next to your other patches. | |
1020 | ||
1021 | . The `-o psuh/` option tells `format-patch` to place the patch | |
1022 | files into a directory. This is useful because `git send-email` | |
1023 | can take a directory and send out all the patches from there. | |
1024 | ||
1025 | . The `--base=auto` option tells the command to record the "base | |
1026 | commit", on which the recipient is expected to apply the patch | |
1027 | series. The `auto` value will cause `format-patch` to compute | |
1028 | the base commit automatically, which is the merge base of tip | |
1029 | commit of the remote-tracking branch and the specified revision | |
1030 | range. | |
1031 | ||
1032 | . The `psuh@{u}..psuh` option tells `format-patch` to generate | |
1033 | patches for the commits you created on the `psuh` branch since it | |
1034 | forked from its upstream (which is `origin/master` if you | |
1035 | followed the example in the "Set up your workspace" section). If | |
1036 | you are already on the `psuh` branch, you can just say `@{u}`, | |
1037 | which means "commits on the current branch since it forked from | |
1038 | its upstream", which is the same thing. | |
1039 | ||
1040 | The command will make one patch file per commit. After you | |
76644e32 ES |
1041 | run, you can go have a look at each of the patches with your favorite text |
1042 | editor and make sure everything looks alright; however, it's not recommended to | |
1043 | make code fixups via the patch file. It's a better idea to make the change the | |
1044 | normal way using `git rebase -i` or by adding a new commit than by modifying a | |
1045 | patch. | |
1046 | ||
1047 | NOTE: Optionally, you can also use the `--rfc` flag to prefix your patch subject | |
1048 | with ``[RFC PATCH]'' instead of ``[PATCH]''. RFC stands for ``request for | |
1049 | comments'' and indicates that while your code isn't quite ready for submission, | |
1050 | you'd like to begin the code review process. This can also be used when your | |
1051 | patch is a proposal, but you aren't sure whether the community wants to solve | |
1052 | the problem with that approach or not - to conduct a sort of design review. You | |
1053 | may also see on the list patches marked ``WIP'' - this means they are incomplete | |
1054 | but want reviewers to look at what they have so far. You can add this flag with | |
1055 | `--subject-prefix=WIP`. | |
1056 | ||
1057 | Check and make sure that your patches and cover letter template exist in the | |
1058 | directory you specified - you're nearly ready to send out your review! | |
1059 | ||
afc8c925 | 1060 | [[preparing-cover-letter]] |
76644e32 ES |
1061 | === Preparing Email |
1062 | ||
e97d474c PB |
1063 | Since you invoked `format-patch` with `--cover-letter`, you've already got a |
1064 | cover letter template ready. Open it up in your favorite editor. | |
76644e32 ES |
1065 | |
1066 | You should see a number of headers present already. Check that your `From:` | |
e97d474c PB |
1067 | header is correct. Then modify your `Subject:` (see <<cover-letter,above>> for |
1068 | how to choose good title for your patch series): | |
76644e32 ES |
1069 | |
1070 | ---- | |
e97d474c | 1071 | Subject: [PATCH 0/7] Add the 'psuh' command |
76644e32 ES |
1072 | ---- |
1073 | ||
1074 | Make sure you retain the ``[PATCH 0/X]'' part; that's what indicates to the Git | |
e97d474c PB |
1075 | community that this email is the beginning of a patch series, and many |
1076 | reviewers filter their email for this type of flag. | |
76644e32 ES |
1077 | |
1078 | You'll need to add some extra parameters when you invoke `git send-email` to add | |
1079 | the cover letter. | |
1080 | ||
e97d474c PB |
1081 | Next you'll have to fill out the body of your cover letter. Again, see |
1082 | <<cover-letter,above>> for what content to include. | |
76644e32 ES |
1083 | |
1084 | The template created by `git format-patch --cover-letter` includes a diffstat. | |
1085 | This gives reviewers a summary of what they're in for when reviewing your topic. | |
1086 | The one generated for `psuh` from the sample implementation looks like this: | |
1087 | ||
1088 | ---- | |
1089 | Documentation/git-psuh.txt | 40 +++++++++++++++++++++ | |
1090 | Makefile | 1 + | |
1091 | builtin.h | 1 + | |
1092 | builtin/psuh.c | 73 ++++++++++++++++++++++++++++++++++++++ | |
1093 | git.c | 1 + | |
1094 | t/t9999-psuh-tutorial.sh | 12 +++++++ | |
1095 | 6 files changed, 128 insertions(+) | |
1096 | create mode 100644 Documentation/git-psuh.txt | |
1097 | create mode 100644 builtin/psuh.c | |
1098 | create mode 100755 t/t9999-psuh-tutorial.sh | |
1099 | ---- | |
1100 | ||
1101 | Finally, the letter will include the version of Git used to generate the | |
1102 | patches. You can leave that string alone. | |
1103 | ||
5ef811ac | 1104 | [[sending-git-send-email]] |
76644e32 ES |
1105 | === Sending Email |
1106 | ||
1107 | At this point you should have a directory `psuh/` which is filled with your | |
1108 | patches and a cover letter. Time to mail it out! You can send it like this: | |
1109 | ||
1110 | ---- | |
1111 | $ git send-email --to=target@example.com psuh/*.patch | |
1112 | ---- | |
1113 | ||
1114 | NOTE: Check `git help send-email` for some other options which you may find | |
1115 | valuable, such as changing the Reply-to address or adding more CC and BCC lines. | |
1116 | ||
1117 | NOTE: When you are sending a real patch, it will go to git@vger.kernel.org - but | |
1118 | please don't send your patchset from the tutorial to the real mailing list! For | |
1119 | now, you can send it to yourself, to make sure you understand how it will look. | |
1120 | ||
1121 | After you run the command above, you will be presented with an interactive | |
1122 | prompt for each patch that's about to go out. This gives you one last chance to | |
1123 | edit or quit sending something (but again, don't edit code this way). Once you | |
1124 | press `y` or `a` at these prompts your emails will be sent! Congratulations! | |
1125 | ||
1126 | Awesome, now the community will drop everything and review your changes. (Just | |
1127 | kidding - be patient!) | |
1128 | ||
5ef811ac | 1129 | [[v2-git-send-email]] |
76644e32 ES |
1130 | === Sending v2 |
1131 | ||
1cc31e15 GC |
1132 | This section will focus on how to send a v2 of your patchset. To learn what |
1133 | should go into v2, skip ahead to <<reviewing,Responding to Reviews>> for | |
1134 | information on how to handle comments from reviewers. | |
1135 | ||
1136 | We'll reuse our `psuh` topic branch for v2. Before we make any changes, we'll | |
1137 | mark the tip of our v1 branch for easy reference: | |
76644e32 | 1138 | |
1cc31e15 GC |
1139 | ---- |
1140 | $ git checkout psuh | |
1141 | $ git branch psuh-v1 | |
1142 | ---- | |
76644e32 | 1143 | |
1cc31e15 GC |
1144 | Refine your patch series by using `git rebase -i` to adjust commits based upon |
1145 | reviewer comments. Once the patch series is ready for submission, generate your | |
1146 | patches again, but with some new flags: | |
76644e32 ES |
1147 | |
1148 | ---- | |
1cc31e15 | 1149 | $ git format-patch -v2 --cover-letter -o psuh/ --range-diff master..psuh-v1 master.. |
76644e32 ES |
1150 | ---- |
1151 | ||
1cc31e15 GC |
1152 | The `--range-diff master..psuh-v1` parameter tells `format-patch` to include a |
1153 | range-diff between `psuh-v1` and `psuh` in the cover letter (see | |
1154 | linkgit:git-range-diff[1]). This helps tell reviewers about the differences | |
1155 | between your v1 and v2 patches. | |
1156 | ||
1157 | The `-v2` parameter tells `format-patch` to output your patches | |
1158 | as version "2". For instance, you may notice that your v2 patches are | |
1159 | all named like `v2-000n-my-commit-subject.patch`. `-v2` will also format | |
1160 | your patches by prefixing them with "[PATCH v2]" instead of "[PATCH]", | |
1161 | and your range-diff will be prefaced with "Range-diff against v1". | |
1162 | ||
72991ff5 | 1163 | After you run this command, `format-patch` will output the patches to the `psuh/` |
1cc31e15 GC |
1164 | directory, alongside the v1 patches. Using a single directory makes it easy to |
1165 | refer to the old v1 patches while proofreading the v2 patches, but you will need | |
1166 | to be careful to send out only the v2 patches. We will use a pattern like | |
1167 | "psuh/v2-*.patch" (not "psuh/*.patch", which would match v1 and v2 patches). | |
76644e32 ES |
1168 | |
1169 | Edit your cover letter again. Now is a good time to mention what's different | |
1170 | between your last version and now, if it's something significant. You do not | |
1171 | need the exact same body in your second cover letter; focus on explaining to | |
1172 | reviewers the changes you've made that may not be as visible. | |
1173 | ||
ba4324c4 | 1174 | You will also need to go and find the Message-ID of your previous cover letter. |
76644e32 ES |
1175 | You can either note it when you send the first series, from the output of `git |
1176 | send-email`, or you can look it up on the | |
46c67492 | 1177 | https://lore.kernel.org/git[mailing list]. Find your cover letter in the |
ba4324c4 | 1178 | archives, click on it, then click "permalink" or "raw" to reveal the Message-ID |
76644e32 ES |
1179 | header. It should match: |
1180 | ||
1181 | ---- | |
ba4324c4 | 1182 | Message-ID: <foo.12345.author@example.com> |
76644e32 ES |
1183 | ---- |
1184 | ||
ba4324c4 JH |
1185 | Your Message-ID is `<foo.12345.author@example.com>`. This example will be used |
1186 | below as well; make sure to replace it with the correct Message-ID for your | |
1187 | **previous cover letter** - that is, if you're sending v2, use the Message-ID | |
1188 | from v1; if you're sending v3, use the Message-ID from v2. | |
76644e32 ES |
1189 | |
1190 | While you're looking at the email, you should also note who is CC'd, as it's | |
1191 | common practice in the mailing list to keep all CCs on a thread. You can add | |
1192 | these CC lines directly to your cover letter with a line like so in the header | |
1193 | (before the Subject line): | |
1194 | ||
1195 | ---- | |
1196 | CC: author@example.com, Othe R <other@example.com> | |
1197 | ---- | |
1198 | ||
1199 | Now send the emails again, paying close attention to which messages you pass in | |
1200 | to the command: | |
1201 | ||
1202 | ---- | |
1203 | $ git send-email --to=target@example.com | |
1204 | --in-reply-to="<foo.12345.author@example.com>" | |
1cc31e15 | 1205 | psuh/v2-*.patch |
76644e32 ES |
1206 | ---- |
1207 | ||
5ef811ac | 1208 | [[single-patch]] |
76644e32 ES |
1209 | === Bonus Chapter: One-Patch Changes |
1210 | ||
1211 | In some cases, your very small change may consist of only one patch. When that | |
1212 | happens, you only need to send one email. Your commit message should already be | |
1213 | meaningful and explain at a high level the purpose (what is happening and why) | |
1214 | of your patch, but if you need to supply even more context, you can do so below | |
1215 | the `---` in your patch. Take the example below, which was generated with `git | |
1216 | format-patch` on a single commit, and then edited to add the content between | |
1217 | the `---` and the diffstat. | |
1218 | ||
1219 | ---- | |
1220 | From 1345bbb3f7ac74abde040c12e737204689a72723 Mon Sep 17 00:00:00 2001 | |
1221 | From: A U Thor <author@example.com> | |
1222 | Date: Thu, 18 Apr 2019 15:11:02 -0700 | |
1223 | Subject: [PATCH] README: change the grammar | |
1224 | ||
1225 | I think it looks better this way. This part of the commit message will | |
1226 | end up in the commit-log. | |
1227 | ||
1228 | Signed-off-by: A U Thor <author@example.com> | |
1229 | --- | |
1230 | Let's have a wild discussion about grammar on the mailing list. This | |
1231 | part of my email will never end up in the commit log. Here is where I | |
1232 | can add additional context to the mailing list about my intent, outside | |
1233 | of the context of the commit log. This section was added after `git | |
1234 | format-patch` was run, by editing the patch file in a text editor. | |
1235 | ||
1236 | README.md | 2 +- | |
1237 | 1 file changed, 1 insertion(+), 1 deletion(-) | |
1238 | ||
1239 | diff --git a/README.md b/README.md | |
1240 | index 88f126184c..38da593a60 100644 | |
1241 | --- a/README.md | |
1242 | +++ b/README.md | |
1243 | @@ -3,7 +3,7 @@ | |
1244 | Git - fast, scalable, distributed revision control system | |
1245 | ========================================================= | |
1246 | ||
1247 | -Git is a fast, scalable, distributed revision control system with an | |
1248 | +Git is a fast, scalable, and distributed revision control system with an | |
1249 | unusually rich command set that provides both high-level operations | |
1250 | and full access to internals. | |
1251 | ||
1252 | -- | |
1253 | 2.21.0.392.gf8f6787159e-goog | |
1254 | ---- | |
1255 | ||
5ef811ac | 1256 | [[now-what]] |
76644e32 ES |
1257 | == My Patch Got Emailed - Now What? |
1258 | ||
1259 | [[reviewing]] | |
1260 | === Responding to Reviews | |
1261 | ||
1262 | After a few days, you will hopefully receive a reply to your patchset with some | |
1263 | comments. Woohoo! Now you can get back to work. | |
1264 | ||
1265 | It's good manners to reply to each comment, notifying the reviewer that you have | |
a6d8d110 | 1266 | made the change suggested, feel the original is better, or that the comment |
76644e32 ES |
1267 | inspired you to do something a new way which is superior to both the original |
1268 | and the suggested change. This way reviewers don't need to inspect your v2 to | |
1269 | figure out whether you implemented their comment or not. | |
1270 | ||
a6d8d110 JH |
1271 | Reviewers may ask you about what you wrote in the patchset, either in |
1272 | the proposed commit log message or in the changes themselves. You | |
1273 | should answer these questions in your response messages, but often the | |
1274 | reason why reviewers asked these questions to understand what you meant | |
1275 | to write is because your patchset needed clarification to be understood. | |
1276 | ||
1277 | Do not be satisfied by just answering their questions in your response | |
1278 | and hear them say that they now understand what you wanted to say. | |
1279 | Update your patches to clarify the points reviewers had trouble with, | |
1280 | and prepare your v2; the words you used to explain your v1 to answer | |
1281 | reviewers' questions may be useful thing to use. Your goal is to make | |
1282 | your v2 clear enough so that it becomes unnecessary for you to give the | |
1283 | same explanation to the next person who reads it. | |
1284 | ||
76644e32 ES |
1285 | If you are going to push back on a comment, be polite and explain why you feel |
1286 | your original is better; be prepared that the reviewer may still disagree with | |
1287 | you, and the rest of the community may weigh in on one side or the other. As | |
1288 | with all code reviews, it's important to keep an open mind to doing something a | |
1289 | different way than you originally planned; other reviewers have a different | |
1290 | perspective on the project than you do, and may be thinking of a valid side | |
1291 | effect which had not occurred to you. It is always okay to ask for clarification | |
1292 | if you aren't sure why a change was suggested, or what the reviewer is asking | |
1293 | you to do. | |
1294 | ||
1295 | Make sure your email client has a plaintext email mode and it is turned on; the | |
1296 | Git list rejects HTML email. Please also follow the mailing list etiquette | |
1297 | outlined in the | |
1298 | https://kernel.googlesource.com/pub/scm/git/git/+/todo/MaintNotes[Maintainer's | |
1299 | Note], which are similar to etiquette rules in most open source communities | |
1300 | surrounding bottom-posting and inline replies. | |
1301 | ||
1302 | When you're making changes to your code, it is cleanest - that is, the resulting | |
1303 | commits are easiest to look at - if you use `git rebase -i` (interactive | |
1304 | rebase). Take a look at this | |
1305 | https://www.oreilly.com/library/view/git-pocket-guide/9781449327507/ch10.html[overview] | |
1306 | from O'Reilly. The general idea is to modify each commit which requires changes; | |
1307 | this way, instead of having a patch A with a mistake, a patch B which was fine | |
1308 | and required no upstream reviews in v1, and a patch C which fixes patch A for | |
1309 | v2, you can just ship a v2 with a correct patch A and correct patch B. This is | |
1310 | changing history, but since it's local history which you haven't shared with | |
1311 | anyone, that is okay for now! (Later, it may not make sense to do this; take a | |
1312 | look at the section below this one for some context.) | |
1313 | ||
5ef811ac | 1314 | [[after-approval]] |
76644e32 ES |
1315 | === After Review Approval |
1316 | ||
828197de JS |
1317 | The Git project has four integration branches: `seen`, `next`, `master`, and |
1318 | `maint`. Your change will be placed into `seen` fairly early on by the maintainer | |
76644e32 ES |
1319 | while it is still in the review process; from there, when it is ready for wider |
1320 | testing, it will be merged into `next`. Plenty of early testers use `next` and | |
1321 | may report issues. Eventually, changes in `next` will make it to `master`, | |
1322 | which is typically considered stable. Finally, when a new release is cut, | |
1323 | `maint` is used to base bugfixes onto. As mentioned at the beginning of this | |
1324 | document, you can read `Documents/SubmittingPatches` for some more info about | |
1325 | the use of the various integration branches. | |
1326 | ||
1327 | Back to now: your code has been lauded by the upstream reviewers. It is perfect. | |
1328 | It is ready to be accepted. You don't need to do anything else; the maintainer | |
1329 | will merge your topic branch to `next` and life is good. | |
1330 | ||
1331 | However, if you discover it isn't so perfect after this point, you may need to | |
1332 | take some special steps depending on where you are in the process. | |
1333 | ||
1334 | If the maintainer has announced in the "What's cooking in git.git" email that | |
1335 | your topic is marked for `next` - that is, that they plan to merge it to `next` | |
1336 | but have not yet done so - you should send an email asking the maintainer to | |
1337 | wait a little longer: "I've sent v4 of my series and you marked it for `next`, | |
1338 | but I need to change this and that - please wait for v5 before you merge it." | |
1339 | ||
1340 | If the topic has already been merged to `next`, rather than modifying your | |
1341 | patches with `git rebase -i`, you should make further changes incrementally - | |
1342 | that is, with another commit, based on top of the maintainer's topic branch as | |
1343 | detailed in https://github.com/gitster/git. Your work is still in the same topic | |
1344 | but is now incremental, rather than a wholesale rewrite of the topic branch. | |
1345 | ||
1346 | The topic branches in the maintainer's GitHub are mirrored in GitGitGadget, so | |
1347 | if you're sending your reviews out that way, you should be sure to open your PR | |
1348 | against the appropriate GitGitGadget/Git branch. | |
1349 | ||
1350 | If you're using `git send-email`, you can use it the same way as before, but you | |
1351 | should generate your diffs from `<topic>..<mybranch>` and base your work on | |
1352 | `<topic>` instead of `master`. |