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76644e32 ES |
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 | ||
5ef811ac | 26 | [[getting-started]] |
76644e32 ES |
27 | == Getting Started |
28 | ||
5ef811ac | 29 | [[cloning]] |
76644e32 ES |
30 | === Clone the Git Repository |
31 | ||
32 | Git is mirrored in a number of locations. Clone the repository from one of them; | |
33 | https://git-scm.com/downloads suggests one of the best places to clone from is | |
34 | the mirror on GitHub. | |
35 | ||
36 | ---- | |
37 | $ git clone https://github.com/git/git git | |
2656fb16 | 38 | $ cd git |
76644e32 ES |
39 | ---- |
40 | ||
3ada78de ES |
41 | [[dependencies]] |
42 | === Installing Dependencies | |
43 | ||
44 | To build Git from source, you need to have a handful of dependencies installed | |
45 | on your system. For a hint of what's needed, you can take a look at | |
46 | `INSTALL`, paying close attention to the section about Git's dependencies on | |
47 | external programs and libraries. That document mentions a way to "test-drive" | |
48 | our freshly built Git without installing; that's the method we'll be using in | |
49 | this tutorial. | |
50 | ||
51 | Make sure that your environment has everything you need by building your brand | |
52 | new clone of Git from the above step: | |
53 | ||
54 | ---- | |
55 | $ make | |
56 | ---- | |
57 | ||
58 | NOTE: The Git build is parallelizable. `-j#` is not included above but you can | |
59 | use it as you prefer, here and elsewhere. | |
60 | ||
5ef811ac | 61 | [[identify-problem]] |
76644e32 ES |
62 | === Identify Problem to Solve |
63 | ||
64 | //// | |
65 | Use + to indicate fixed-width here; couldn't get ` to work nicely with the | |
66 | quotes around "Pony Saying 'Um, Hello'". | |
67 | //// | |
68 | In this tutorial, we will add a new command, +git psuh+, short for ``Pony Saying | |
69 | `Um, Hello''' - a feature which has gone unimplemented despite a high frequency | |
70 | of invocation during users' typical daily workflow. | |
71 | ||
72 | (We've seen some other effort in this space with the implementation of popular | |
73 | commands such as `sl`.) | |
74 | ||
5ef811ac | 75 | [[setup-workspace]] |
76644e32 ES |
76 | === Set Up Your Workspace |
77 | ||
78 | Let's start by making a development branch to work on our changes. Per | |
79 | `Documentation/SubmittingPatches`, since a brand new command is a new feature, | |
80 | it's fine to base your work on `master`. However, in the future for bugfixes, | |
81 | etc., you should check that document and base it on the appropriate branch. | |
82 | ||
83 | For the purposes of this document, we will base all our work on the `master` | |
84 | branch of the upstream project. Create the `psuh` branch you will use for | |
85 | development like so: | |
86 | ||
87 | ---- | |
88 | $ git checkout -b psuh origin/master | |
89 | ---- | |
90 | ||
91 | We'll make a number of commits here in order to demonstrate how to send a topic | |
92 | with multiple patches up for review simultaneously. | |
93 | ||
5ef811ac | 94 | [[code-it-up]] |
76644e32 ES |
95 | == Code It Up! |
96 | ||
97 | NOTE: A reference implementation can be found at | |
98 | https://github.com/nasamuffin/git/tree/psuh. | |
99 | ||
5ef811ac | 100 | [[add-new-command]] |
76644e32 ES |
101 | === Adding a New Command |
102 | ||
103 | Lots of the subcommands are written as builtins, which means they are | |
104 | implemented in C and compiled into the main `git` executable. Implementing the | |
105 | very simple `psuh` command as a built-in will demonstrate the structure of the | |
106 | codebase, the internal API, and the process of working together as a contributor | |
107 | with the reviewers and maintainer to integrate this change into the system. | |
108 | ||
109 | Built-in subcommands are typically implemented in a function named "cmd_" | |
110 | followed by the name of the subcommand, in a source file named after the | |
111 | subcommand and contained within `builtin/`. So it makes sense to implement your | |
112 | command in `builtin/psuh.c`. Create that file, and within it, write the entry | |
113 | point for your command in a function matching the style and signature: | |
114 | ||
115 | ---- | |
116 | int cmd_psuh(int argc, const char **argv, const char *prefix) | |
117 | ---- | |
118 | ||
119 | We'll also need to add the declaration of psuh; open up `builtin.h`, find the | |
24c68179 PS |
120 | declaration for `cmd_pull`, and add a new line for `psuh` immediately before it, |
121 | in order to keep the declarations alphabetically sorted: | |
76644e32 ES |
122 | |
123 | ---- | |
124 | int cmd_psuh(int argc, const char **argv, const char *prefix); | |
125 | ---- | |
126 | ||
127 | Be sure to `#include "builtin.h"` in your `psuh.c`. | |
128 | ||
129 | Go ahead and add some throwaway printf to that function. This is a decent | |
130 | starting point as we can now add build rules and register the command. | |
131 | ||
132 | NOTE: Your throwaway text, as well as much of the text you will be adding over | |
133 | the course of this tutorial, is user-facing. That means it needs to be | |
134 | localizable. Take a look at `po/README` under "Marking strings for translation". | |
135 | Throughout the tutorial, we will mark strings for translation as necessary; you | |
136 | should also do so when writing your user-facing commands in the future. | |
137 | ||
138 | ---- | |
139 | int cmd_psuh(int argc, const char **argv, const char *prefix) | |
140 | { | |
141 | printf(_("Pony saying hello goes here.\n")); | |
142 | return 0; | |
143 | } | |
144 | ---- | |
145 | ||
24c68179 | 146 | Let's try to build it. Open `Makefile`, find where `builtin/pull.o` is added |
76644e32 ES |
147 | to `BUILTIN_OBJS`, and add `builtin/psuh.o` in the same way next to it in |
148 | alphabetical order. Once you've done so, move to the top-level directory and | |
149 | build simply with `make`. Also add the `DEVELOPER=1` variable to turn on | |
150 | some additional warnings: | |
151 | ||
152 | ---- | |
153 | $ echo DEVELOPER=1 >config.mak | |
154 | $ make | |
155 | ---- | |
156 | ||
157 | NOTE: When you are developing the Git project, it's preferred that you use the | |
158 | `DEVELOPER` flag; if there's some reason it doesn't work for you, you can turn | |
159 | it off, but it's a good idea to mention the problem to the mailing list. | |
160 | ||
76644e32 ES |
161 | Great, now your new command builds happily on its own. But nobody invokes it. |
162 | Let's change that. | |
163 | ||
164 | The list of commands lives in `git.c`. We can register a new command by adding | |
165 | a `cmd_struct` to the `commands[]` array. `struct cmd_struct` takes a string | |
166 | with the command name, a function pointer to the command implementation, and a | |
167 | setup option flag. For now, let's keep mimicking `push`. Find the line where | |
168 | `cmd_push` is registered, copy it, and modify it for `cmd_psuh`, placing the new | |
24c68179 | 169 | line in alphabetical order (immediately before `cmd_pull`). |
76644e32 ES |
170 | |
171 | The options are documented in `builtin.h` under "Adding a new built-in." Since | |
172 | we hope to print some data about the user's current workspace context later, | |
173 | we need a Git directory, so choose `RUN_SETUP` as your only option. | |
174 | ||
175 | Go ahead and build again. You should see a clean build, so let's kick the tires | |
176 | and see if it works. There's a binary you can use to test with in the | |
177 | `bin-wrappers` directory. | |
178 | ||
179 | ---- | |
180 | $ ./bin-wrappers/git psuh | |
181 | ---- | |
182 | ||
183 | Check it out! You've got a command! Nice work! Let's commit this. | |
184 | ||
2656fb16 ES |
185 | `git status` reveals modified `Makefile`, `builtin.h`, and `git.c` as well as |
186 | untracked `builtin/psuh.c` and `git-psuh`. First, let's take care of the binary, | |
24c68179 | 187 | which should be ignored. Open `.gitignore` in your editor, find `/git-pull`, and |
2656fb16 ES |
188 | add an entry for your new command in alphabetical order: |
189 | ||
190 | ---- | |
191 | ... | |
192 | /git-prune-packed | |
193 | /git-psuh | |
194 | /git-pull | |
195 | /git-push | |
196 | /git-quiltimport | |
197 | /git-range-diff | |
198 | ... | |
199 | ---- | |
200 | ||
201 | Checking `git status` again should show that `git-psuh` has been removed from | |
202 | the untracked list and `.gitignore` has been added to the modified list. Now we | |
203 | can stage and commit: | |
204 | ||
76644e32 | 205 | ---- |
2656fb16 | 206 | $ git add Makefile builtin.h builtin/psuh.c git.c .gitignore |
76644e32 ES |
207 | $ git commit -s |
208 | ---- | |
209 | ||
210 | You will be presented with your editor in order to write a commit message. Start | |
211 | the commit with a 50-column or less subject line, including the name of the | |
212 | component you're working on, followed by a blank line (always required) and then | |
213 | the body of your commit message, which should provide the bulk of the context. | |
214 | Remember to be explicit and provide the "Why" of your change, especially if it | |
215 | couldn't easily be understood from your diff. When editing your commit message, | |
216 | don't remove the Signed-off-by line which was added by `-s` above. | |
217 | ||
218 | ---- | |
219 | psuh: add a built-in by popular demand | |
220 | ||
221 | Internal metrics indicate this is a command many users expect to be | |
222 | present. So here's an implementation to help drive customer | |
223 | satisfaction and engagement: a pony which doubtfully greets the user, | |
224 | or, a Pony Saying "Um, Hello" (PSUH). | |
225 | ||
226 | This commit message is intentionally formatted to 72 columns per line, | |
227 | starts with a single line as "commit message subject" that is written as | |
228 | if to command the codebase to do something (add this, teach a command | |
229 | that). The body of the message is designed to add information about the | |
230 | commit that is not readily deduced from reading the associated diff, | |
231 | such as answering the question "why?". | |
232 | ||
233 | Signed-off-by: A U Thor <author@example.com> | |
234 | ---- | |
235 | ||
236 | Go ahead and inspect your new commit with `git show`. "psuh:" indicates you | |
237 | have modified mainly the `psuh` command. The subject line gives readers an idea | |
238 | of what you've changed. The sign-off line (`-s`) indicates that you agree to | |
239 | the Developer's Certificate of Origin 1.1 (see the | |
240 | `Documentation/SubmittingPatches` +++[[dco]]+++ header). | |
241 | ||
242 | For the remainder of the tutorial, the subject line only will be listed for the | |
243 | sake of brevity. However, fully-fleshed example commit messages are available | |
244 | on the reference implementation linked at the top of this document. | |
245 | ||
5ef811ac | 246 | [[implementation]] |
76644e32 ES |
247 | === Implementation |
248 | ||
249 | It's probably useful to do at least something besides printing out a string. | |
250 | Let's start by having a look at everything we get. | |
251 | ||
2656fb16 ES |
252 | Modify your `cmd_psuh` implementation to dump the args you're passed, keeping |
253 | existing `printf()` calls in place: | |
76644e32 ES |
254 | |
255 | ---- | |
256 | int i; | |
257 | ||
258 | ... | |
259 | ||
260 | printf(Q_("Your args (there is %d):\n", | |
261 | "Your args (there are %d):\n", | |
262 | argc), | |
263 | argc); | |
264 | for (i = 0; i < argc; i++) | |
265 | printf("%d: %s\n", i, argv[i]); | |
266 | ||
267 | printf(_("Your current working directory:\n<top-level>%s%s\n"), | |
268 | prefix ? "/" : "", prefix ? prefix : ""); | |
269 | ||
270 | ---- | |
271 | ||
272 | Build and try it. As you may expect, there's pretty much just whatever we give | |
273 | on the command line, including the name of our command. (If `prefix` is empty | |
274 | for you, try `cd Documentation/ && ../bin-wrappers/git psuh`). That's not so | |
275 | helpful. So what other context can we get? | |
276 | ||
277 | Add a line to `#include "config.h"`. Then, add the following bits to the | |
278 | function body: | |
279 | ||
280 | ---- | |
281 | const char *cfg_name; | |
282 | ||
283 | ... | |
284 | ||
2656fb16 | 285 | git_config(git_default_config, NULL); |
76644e32 ES |
286 | if (git_config_get_string_const("user.name", &cfg_name) > 0) |
287 | printf(_("No name is found in config\n")); | |
288 | else | |
289 | printf(_("Your name: %s\n"), cfg_name); | |
290 | ---- | |
291 | ||
292 | `git_config()` will grab the configuration from config files known to Git and | |
293 | apply standard precedence rules. `git_config_get_string_const()` will look up | |
294 | a specific key ("user.name") and give you the value. There are a number of | |
295 | single-key lookup functions like this one; you can see them all (and more info | |
296 | about how to use `git_config()`) in `Documentation/technical/api-config.txt`. | |
297 | ||
298 | You should see that the name printed matches the one you see when you run: | |
299 | ||
300 | ---- | |
301 | $ git config --get user.name | |
302 | ---- | |
303 | ||
304 | Great! Now we know how to check for values in the Git config. Let's commit this | |
305 | too, so we don't lose our progress. | |
306 | ||
307 | ---- | |
308 | $ git add builtin/psuh.c | |
309 | $ git commit -sm "psuh: show parameters & config opts" | |
310 | ---- | |
311 | ||
312 | NOTE: Again, the above is for sake of brevity in this tutorial. In a real change | |
313 | you should not use `-m` but instead use the editor to write a meaningful | |
314 | message. | |
315 | ||
316 | Still, it'd be nice to know what the user's working context is like. Let's see | |
317 | if we can print the name of the user's current branch. We can mimic the | |
318 | `git status` implementation; the printer is located in `wt-status.c` and we can | |
319 | see that the branch is held in a `struct wt_status`. | |
320 | ||
321 | `wt_status_print()` gets invoked by `cmd_status()` in `builtin/commit.c`. | |
322 | Looking at that implementation we see the status config being populated like so: | |
323 | ||
324 | ---- | |
325 | status_init_config(&s, git_status_config); | |
326 | ---- | |
327 | ||
328 | But as we drill down, we can find that `status_init_config()` wraps a call | |
329 | to `git_config()`. Let's modify the code we wrote in the previous commit. | |
330 | ||
331 | Be sure to include the header to allow you to use `struct wt_status`: | |
332 | ---- | |
333 | #include "wt-status.h" | |
334 | ---- | |
335 | ||
336 | Then modify your `cmd_psuh` implementation to declare your `struct wt_status`, | |
337 | prepare it, and print its contents: | |
338 | ||
339 | ---- | |
340 | struct wt_status status; | |
341 | ||
342 | ... | |
343 | ||
344 | wt_status_prepare(the_repository, &status); | |
345 | git_config(git_default_config, &status); | |
346 | ||
347 | ... | |
348 | ||
349 | printf(_("Your current branch: %s\n"), status.branch); | |
350 | ---- | |
351 | ||
352 | Run it again. Check it out - here's the (verbose) name of your current branch! | |
353 | ||
354 | Let's commit this as well. | |
355 | ||
356 | ---- | |
2656fb16 | 357 | $ git add builtin/psuh.c |
76644e32 ES |
358 | $ git commit -sm "psuh: print the current branch" |
359 | ---- | |
360 | ||
361 | Now let's see if we can get some info about a specific commit. | |
362 | ||
363 | Luckily, there are some helpers for us here. `commit.h` has a function called | |
364 | `lookup_commit_reference_by_name` to which we can simply provide a hardcoded | |
365 | string; `pretty.h` has an extremely handy `pp_commit_easy()` call which doesn't | |
366 | require a full format object to be passed. | |
367 | ||
368 | Add the following includes: | |
369 | ||
370 | ---- | |
371 | #include "commit.h" | |
372 | #include "pretty.h" | |
373 | ---- | |
374 | ||
375 | Then, add the following lines within your implementation of `cmd_psuh()` near | |
376 | the declarations and the logic, respectively. | |
377 | ||
378 | ---- | |
379 | struct commit *c = NULL; | |
380 | struct strbuf commitline = STRBUF_INIT; | |
381 | ||
382 | ... | |
383 | ||
384 | c = lookup_commit_reference_by_name("origin/master"); | |
385 | ||
386 | if (c != NULL) { | |
387 | pp_commit_easy(CMIT_FMT_ONELINE, c, &commitline); | |
388 | printf(_("Current commit: %s\n"), commitline.buf); | |
389 | } | |
390 | ---- | |
391 | ||
392 | The `struct strbuf` provides some safety belts to your basic `char*`, one of | |
393 | which is a length member to prevent buffer overruns. It needs to be initialized | |
394 | nicely with `STRBUF_INIT`. Keep it in mind when you need to pass around `char*`. | |
395 | ||
396 | `lookup_commit_reference_by_name` resolves the name you pass it, so you can play | |
397 | with the value there and see what kind of things you can come up with. | |
398 | ||
399 | `pp_commit_easy` is a convenience wrapper in `pretty.h` that takes a single | |
400 | format enum shorthand, rather than an entire format struct. It then | |
401 | pretty-prints the commit according to that shorthand. These are similar to the | |
402 | formats available with `--pretty=FOO` in many Git commands. | |
403 | ||
404 | Build it and run, and if you're using the same name in the example, you should | |
405 | see the subject line of the most recent commit in `origin/master` that you know | |
406 | about. Neat! Let's commit that as well. | |
407 | ||
408 | ---- | |
2656fb16 | 409 | $ git add builtin/psuh.c |
76644e32 ES |
410 | $ git commit -sm "psuh: display the top of origin/master" |
411 | ---- | |
412 | ||
5ef811ac | 413 | [[add-documentation]] |
76644e32 ES |
414 | === Adding Documentation |
415 | ||
416 | Awesome! You've got a fantastic new command that you're ready to share with the | |
417 | community. But hang on just a minute - this isn't very user-friendly. Run the | |
418 | following: | |
419 | ||
420 | ---- | |
421 | $ ./bin-wrappers/git help psuh | |
422 | ---- | |
423 | ||
424 | Your new command is undocumented! Let's fix that. | |
425 | ||
426 | Take a look at `Documentation/git-*.txt`. These are the manpages for the | |
427 | subcommands that Git knows about. You can open these up and take a look to get | |
428 | acquainted with the format, but then go ahead and make a new file | |
429 | `Documentation/git-psuh.txt`. Like with most of the documentation in the Git | |
430 | project, help pages are written with AsciiDoc (see CodingGuidelines, "Writing | |
431 | Documentation" section). Use the following template to fill out your own | |
432 | manpage: | |
433 | ||
434 | // Surprisingly difficult to embed AsciiDoc source within AsciiDoc. | |
435 | [listing] | |
436 | .... | |
437 | git-psuh(1) | |
438 | =========== | |
439 | ||
440 | NAME | |
441 | ---- | |
442 | git-psuh - Delight users' typo with a shy horse | |
443 | ||
444 | ||
445 | SYNOPSIS | |
446 | -------- | |
447 | [verse] | |
b37e0ec3 | 448 | 'git-psuh [<arg>...]' |
76644e32 ES |
449 | |
450 | DESCRIPTION | |
451 | ----------- | |
452 | ... | |
453 | ||
454 | OPTIONS[[OPTIONS]] | |
455 | ------------------ | |
456 | ... | |
457 | ||
458 | OUTPUT | |
459 | ------ | |
460 | ... | |
461 | ||
76644e32 ES |
462 | GIT |
463 | --- | |
464 | Part of the linkgit:git[1] suite | |
465 | .... | |
466 | ||
467 | The most important pieces of this to note are the file header, underlined by =, | |
468 | the NAME section, and the SYNOPSIS, which would normally contain the grammar if | |
469 | your command took arguments. Try to use well-established manpage headers so your | |
470 | documentation is consistent with other Git and UNIX manpages; this makes life | |
471 | easier for your user, who can skip to the section they know contains the | |
472 | information they need. | |
473 | ||
474 | Now that you've written your manpage, you'll need to build it explicitly. We | |
475 | convert your AsciiDoc to troff which is man-readable like so: | |
476 | ||
477 | ---- | |
478 | $ make all doc | |
479 | $ man Documentation/git-psuh.1 | |
480 | ---- | |
481 | ||
482 | or | |
483 | ||
484 | ---- | |
485 | $ make -C Documentation/ git-psuh.1 | |
486 | $ man Documentation/git-psuh.1 | |
487 | ---- | |
488 | ||
489 | NOTE: You may need to install the package `asciidoc` to get this to work. | |
490 | ||
491 | While this isn't as satisfying as running through `git help`, you can at least | |
492 | check that your help page looks right. | |
493 | ||
494 | You can also check that the documentation coverage is good (that is, the project | |
495 | sees that your command has been implemented as well as documented) by running | |
496 | `make check-docs` from the top-level. | |
497 | ||
498 | Go ahead and commit your new documentation change. | |
499 | ||
5ef811ac | 500 | [[add-usage]] |
76644e32 ES |
501 | === Adding Usage Text |
502 | ||
503 | Try and run `./bin-wrappers/git psuh -h`. Your command should crash at the end. | |
504 | That's because `-h` is a special case which your command should handle by | |
505 | printing usage. | |
506 | ||
507 | Take a look at `Documentation/technical/api-parse-options.txt`. This is a handy | |
508 | tool for pulling out options you need to be able to handle, and it takes a | |
509 | usage string. | |
510 | ||
b37e0ec3 CC |
511 | In order to use it, we'll need to prepare a NULL-terminated array of usage |
512 | strings and a `builtin_psuh_options` array. | |
76644e32 | 513 | |
b37e0ec3 CC |
514 | Add a line to `#include "parse-options.h"`. |
515 | ||
516 | At global scope, add your array of usage strings: | |
76644e32 ES |
517 | |
518 | ---- | |
519 | static const char * const psuh_usage[] = { | |
b37e0ec3 | 520 | N_("git psuh [<arg>...]"), |
76644e32 ES |
521 | NULL, |
522 | }; | |
523 | ---- | |
524 | ||
525 | Then, within your `cmd_psuh()` implementation, we can declare and populate our | |
526 | `option` struct. Ours is pretty boring but you can add more to it if you want to | |
527 | explore `parse_options()` in more detail: | |
528 | ||
529 | ---- | |
530 | struct option options[] = { | |
531 | OPT_END() | |
532 | }; | |
533 | ---- | |
534 | ||
535 | Finally, before you print your args and prefix, add the call to | |
536 | `parse-options()`: | |
537 | ||
538 | ---- | |
539 | argc = parse_options(argc, argv, prefix, options, psuh_usage, 0); | |
540 | ---- | |
541 | ||
542 | This call will modify your `argv` parameter. It will strip the options you | |
543 | specified in `options` from `argv` and the locations pointed to from `options` | |
544 | entries will be updated. Be sure to replace your `argc` with the result from | |
545 | `parse_options()`, or you will be confused if you try to parse `argv` later. | |
546 | ||
547 | It's worth noting the special argument `--`. As you may be aware, many Unix | |
548 | commands use `--` to indicate "end of named parameters" - all parameters after | |
549 | the `--` are interpreted merely as positional arguments. (This can be handy if | |
550 | you want to pass as a parameter something which would usually be interpreted as | |
551 | a flag.) `parse_options()` will terminate parsing when it reaches `--` and give | |
552 | you the rest of the options afterwards, untouched. | |
553 | ||
4ed55629 ES |
554 | Now that you have a usage hint, you can teach Git how to show it in the general |
555 | command list shown by `git help git` or `git help -a`, which is generated from | |
556 | `command-list.txt`. Find the line for 'git-pull' so you can add your 'git-psuh' | |
557 | line above it in alphabetical order. Now, we can add some attributes about the | |
558 | command which impacts where it shows up in the aforementioned help commands. The | |
559 | top of `command-list.txt` shares some information about what each attribute | |
560 | means; in those help pages, the commands are sorted according to these | |
561 | attributes. `git psuh` is user-facing, or porcelain - so we will mark it as | |
562 | "mainporcelain". For "mainporcelain" commands, the comments at the top of | |
563 | `command-list.txt` indicate we can also optionally add an attribute from another | |
564 | list; since `git psuh` shows some information about the user's workspace but | |
565 | doesn't modify anything, let's mark it as "info". Make sure to keep your | |
566 | attributes in the same style as the rest of `command-list.txt` using spaces to | |
567 | align and delineate them: | |
568 | ||
569 | ---- | |
570 | git-prune-packed plumbingmanipulators | |
571 | git-psuh mainporcelain info | |
572 | git-pull mainporcelain remote | |
573 | git-push mainporcelain remote | |
574 | ---- | |
575 | ||
76644e32 ES |
576 | Build again. Now, when you run with `-h`, you should see your usage printed and |
577 | your command terminated before anything else interesting happens. Great! | |
578 | ||
579 | Go ahead and commit this one, too. | |
580 | ||
5ef811ac | 581 | [[testing]] |
76644e32 ES |
582 | == Testing |
583 | ||
584 | It's important to test your code - even for a little toy command like this one. | |
585 | Moreover, your patch won't be accepted into the Git tree without tests. Your | |
586 | tests should: | |
587 | ||
588 | * Illustrate the current behavior of the feature | |
589 | * Prove the current behavior matches the expected behavior | |
590 | * Ensure the externally-visible behavior isn't broken in later changes | |
591 | ||
592 | So let's write some tests. | |
593 | ||
594 | Related reading: `t/README` | |
595 | ||
5ef811ac | 596 | [[overview-test-structure]] |
76644e32 ES |
597 | === Overview of Testing Structure |
598 | ||
599 | The tests in Git live in `t/` and are named with a 4-digit decimal number using | |
600 | the schema shown in the Naming Tests section of `t/README`. | |
601 | ||
5ef811ac | 602 | [[write-new-test]] |
76644e32 ES |
603 | === Writing Your Test |
604 | ||
605 | Since this a toy command, let's go ahead and name the test with t9999. However, | |
606 | as many of the family/subcmd combinations are full, best practice seems to be | |
607 | to find a command close enough to the one you've added and share its naming | |
608 | space. | |
609 | ||
610 | Create a new file `t/t9999-psuh-tutorial.sh`. Begin with the header as so (see | |
611 | "Writing Tests" and "Source 'test-lib.sh'" in `t/README`): | |
612 | ||
613 | ---- | |
614 | #!/bin/sh | |
615 | ||
616 | test_description='git-psuh test | |
617 | ||
618 | This test runs git-psuh and makes sure it does not crash.' | |
619 | ||
620 | . ./test-lib.sh | |
621 | ---- | |
622 | ||
623 | Tests are framed inside of a `test_expect_success` in order to output TAP | |
624 | formatted results. Let's make sure that `git psuh` doesn't exit poorly and does | |
625 | mention the right animal somewhere: | |
626 | ||
627 | ---- | |
628 | test_expect_success 'runs correctly with no args and good output' ' | |
629 | git psuh >actual && | |
630 | test_i18ngrep Pony actual | |
631 | ' | |
632 | ---- | |
633 | ||
634 | Indicate that you've run everything you wanted by adding the following at the | |
635 | bottom of your script: | |
636 | ||
637 | ---- | |
638 | test_done | |
639 | ---- | |
640 | ||
641 | Make sure you mark your test script executable: | |
642 | ||
643 | ---- | |
644 | $ chmod +x t/t9999-psuh-tutorial.sh | |
645 | ---- | |
646 | ||
647 | You can get an idea of whether you created your new test script successfully | |
648 | by running `make -C t test-lint`, which will check for things like test number | |
649 | uniqueness, executable bit, and so on. | |
650 | ||
5ef811ac | 651 | [[local-test]] |
76644e32 ES |
652 | === Running Locally |
653 | ||
654 | Let's try and run locally: | |
655 | ||
656 | ---- | |
657 | $ make | |
658 | $ cd t/ && prove t9999-psuh-tutorial.sh | |
659 | ---- | |
660 | ||
661 | You can run the full test suite and ensure `git-psuh` didn't break anything: | |
662 | ||
663 | ---- | |
664 | $ cd t/ | |
665 | $ prove -j$(nproc) --shuffle t[0-9]*.sh | |
666 | ---- | |
667 | ||
668 | NOTE: You can also do this with `make test` or use any testing harness which can | |
669 | speak TAP. `prove` can run concurrently. `shuffle` randomizes the order the | |
670 | tests are run in, which makes them resilient against unwanted inter-test | |
671 | dependencies. `prove` also makes the output nicer. | |
672 | ||
673 | Go ahead and commit this change, as well. | |
674 | ||
5ef811ac | 675 | [[ready-to-share]] |
76644e32 ES |
676 | == Getting Ready to Share |
677 | ||
678 | You may have noticed already that the Git project performs its code reviews via | |
679 | emailed patches, which are then applied by the maintainer when they are ready | |
680 | and approved by the community. The Git project does not accept patches from | |
681 | pull requests, and the patches emailed for review need to be formatted a | |
682 | specific way. At this point the tutorial diverges, in order to demonstrate two | |
683 | different methods of formatting your patchset and getting it reviewed. | |
684 | ||
685 | The first method to be covered is GitGitGadget, which is useful for those | |
686 | already familiar with GitHub's common pull request workflow. This method | |
687 | requires a GitHub account. | |
688 | ||
689 | The second method to be covered is `git send-email`, which can give slightly | |
690 | more fine-grained control over the emails to be sent. This method requires some | |
691 | setup which can change depending on your system and will not be covered in this | |
692 | tutorial. | |
693 | ||
694 | Regardless of which method you choose, your engagement with reviewers will be | |
695 | the same; the review process will be covered after the sections on GitGitGadget | |
696 | and `git send-email`. | |
697 | ||
5ef811ac | 698 | [[howto-ggg]] |
76644e32 ES |
699 | == Sending Patches via GitGitGadget |
700 | ||
701 | One option for sending patches is to follow a typical pull request workflow and | |
702 | send your patches out via GitGitGadget. GitGitGadget is a tool created by | |
703 | Johannes Schindelin to make life as a Git contributor easier for those used to | |
704 | the GitHub PR workflow. It allows contributors to open pull requests against its | |
705 | mirror of the Git project, and does some magic to turn the PR into a set of | |
706 | emails and send them out for you. It also runs the Git continuous integration | |
707 | suite for you. It's documented at http://gitgitgadget.github.io. | |
708 | ||
5ef811ac | 709 | [[create-fork]] |
76644e32 ES |
710 | === Forking `git/git` on GitHub |
711 | ||
712 | Before you can send your patch off to be reviewed using GitGitGadget, you will | |
713 | need to fork the Git project and upload your changes. First thing - make sure | |
714 | you have a GitHub account. | |
715 | ||
716 | Head to the https://github.com/git/git[GitHub mirror] and look for the Fork | |
717 | button. Place your fork wherever you deem appropriate and create it. | |
718 | ||
5ef811ac | 719 | [[upload-to-fork]] |
76644e32 ES |
720 | === Uploading to Your Own Fork |
721 | ||
722 | To upload your branch to your own fork, you'll need to add the new fork as a | |
723 | remote. You can use `git remote -v` to show the remotes you have added already. | |
724 | From your new fork's page on GitHub, you can press "Clone or download" to get | |
725 | the URL; then you need to run the following to add, replacing your own URL and | |
726 | remote name for the examples provided: | |
727 | ||
728 | ---- | |
729 | $ git remote add remotename git@github.com:remotename/git.git | |
730 | ---- | |
731 | ||
732 | or to use the HTTPS URL: | |
733 | ||
734 | ---- | |
735 | $ git remote add remotename https://github.com/remotename/git/.git | |
736 | ---- | |
737 | ||
738 | Run `git remote -v` again and you should see the new remote showing up. | |
739 | `git fetch remotename` (with the real name of your remote replaced) in order to | |
740 | get ready to push. | |
741 | ||
742 | Next, double-check that you've been doing all your development in a new branch | |
743 | by running `git branch`. If you didn't, now is a good time to move your new | |
744 | commits to their own branch. | |
745 | ||
746 | As mentioned briefly at the beginning of this document, we are basing our work | |
747 | on `master`, so go ahead and update as shown below, or using your preferred | |
748 | workflow. | |
749 | ||
750 | ---- | |
751 | $ git checkout master | |
752 | $ git pull -r | |
753 | $ git rebase master psuh | |
754 | ---- | |
755 | ||
756 | Finally, you're ready to push your new topic branch! (Due to our branch and | |
757 | command name choices, be careful when you type the command below.) | |
758 | ||
759 | ---- | |
760 | $ git push remotename psuh | |
761 | ---- | |
762 | ||
763 | Now you should be able to go and check out your newly created branch on GitHub. | |
764 | ||
5ef811ac | 765 | [[send-pr-ggg]] |
76644e32 ES |
766 | === Sending a PR to GitGitGadget |
767 | ||
768 | In order to have your code tested and formatted for review, you need to start by | |
769 | opening a Pull Request against `gitgitgadget/git`. Head to | |
770 | https://github.com/gitgitgadget/git and open a PR either with the "New pull | |
771 | request" button or the convenient "Compare & pull request" button that may | |
772 | appear with the name of your newly pushed branch. | |
773 | ||
774 | Review the PR's title and description, as it's used by GitGitGadget as the cover | |
775 | letter for your change. When you're happy, submit your pull request. | |
776 | ||
5ef811ac | 777 | [[run-ci-ggg]] |
76644e32 ES |
778 | === Running CI and Getting Ready to Send |
779 | ||
780 | If it's your first time using GitGitGadget (which is likely, as you're using | |
781 | this tutorial) then someone will need to give you permission to use the tool. | |
782 | As mentioned in the GitGitGadget documentation, you just need someone who | |
783 | already uses it to comment on your PR with `/allow <username>`. GitGitGadget | |
784 | will automatically run your PRs through the CI even without the permission given | |
785 | but you will not be able to `/submit` your changes until someone allows you to | |
786 | use the tool. | |
787 | ||
3c8d754c ES |
788 | NOTE: You can typically find someone who can `/allow` you on GitGitGadget by |
789 | either examining recent pull requests where someone has been granted `/allow` | |
790 | (https://github.com/gitgitgadget/git/pulls?utf8=%E2%9C%93&q=is%3Apr+is%3Aopen+%22%2Fallow%22[Search: | |
791 | is:pr is:open "/allow"]), in which case both the author and the person who | |
792 | granted the `/allow` can now `/allow` you, or by inquiring on the | |
793 | https://webchat.freenode.net/#git-devel[#git-devel] IRC channel on Freenode | |
794 | linking your pull request and asking for someone to `/allow` you. | |
795 | ||
76644e32 ES |
796 | If the CI fails, you can update your changes with `git rebase -i` and push your |
797 | branch again: | |
798 | ||
799 | ---- | |
800 | $ git push -f remotename psuh | |
801 | ---- | |
802 | ||
803 | In fact, you should continue to make changes this way up until the point when | |
804 | your patch is accepted into `next`. | |
805 | ||
806 | //// | |
807 | TODO https://github.com/gitgitgadget/gitgitgadget/issues/83 | |
808 | It'd be nice to be able to verify that the patch looks good before sending it | |
809 | to everyone on Git mailing list. | |
5ef811ac | 810 | [[check-work-ggg]] |
76644e32 ES |
811 | === Check Your Work |
812 | //// | |
813 | ||
5ef811ac | 814 | [[send-mail-ggg]] |
76644e32 ES |
815 | === Sending Your Patches |
816 | ||
817 | Now that your CI is passing and someone has granted you permission to use | |
818 | GitGitGadget with the `/allow` command, sending out for review is as simple as | |
819 | commenting on your PR with `/submit`. | |
820 | ||
5ef811ac | 821 | [[responding-ggg]] |
76644e32 ES |
822 | === Updating With Comments |
823 | ||
824 | Skip ahead to <<reviewing,Responding to Reviews>> for information on how to | |
825 | reply to review comments you will receive on the mailing list. | |
826 | ||
827 | Once you have your branch again in the shape you want following all review | |
828 | comments, you can submit again: | |
829 | ||
830 | ---- | |
831 | $ git push -f remotename psuh | |
832 | ---- | |
833 | ||
834 | Next, go look at your pull request against GitGitGadget; you should see the CI | |
835 | has been kicked off again. Now while the CI is running is a good time for you | |
836 | to modify your description at the top of the pull request thread; it will be | |
837 | used again as the cover letter. You should use this space to describe what | |
838 | has changed since your previous version, so that your reviewers have some idea | |
839 | of what they're looking at. When the CI is done running, you can comment once | |
840 | more with `/submit` - GitGitGadget will automatically add a v2 mark to your | |
841 | changes. | |
842 | ||
5ef811ac | 843 | [[howto-git-send-email]] |
76644e32 ES |
844 | == Sending Patches with `git send-email` |
845 | ||
846 | If you don't want to use GitGitGadget, you can also use Git itself to mail your | |
847 | patches. Some benefits of using Git this way include finer grained control of | |
848 | subject line (for example, being able to use the tag [RFC PATCH] in the subject) | |
849 | and being able to send a ``dry run'' mail to yourself to ensure it all looks | |
850 | good before going out to the list. | |
851 | ||
5ef811ac | 852 | [[setup-git-send-email]] |
76644e32 ES |
853 | === Prerequisite: Setting Up `git send-email` |
854 | ||
855 | Configuration for `send-email` can vary based on your operating system and email | |
856 | provider, and so will not be covered in this tutorial, beyond stating that in | |
857 | many distributions of Linux, `git-send-email` is not packaged alongside the | |
858 | typical `git` install. You may need to install this additional package; there | |
859 | are a number of resources online to help you do so. You will also need to | |
860 | determine the right way to configure it to use your SMTP server; again, as this | |
861 | configuration can change significantly based on your system and email setup, it | |
862 | is out of scope for the context of this tutorial. | |
863 | ||
5ef811ac | 864 | [[format-patch]] |
76644e32 ES |
865 | === Preparing Initial Patchset |
866 | ||
867 | Sending emails with Git is a two-part process; before you can prepare the emails | |
868 | themselves, you'll need to prepare the patches. Luckily, this is pretty simple: | |
869 | ||
870 | ---- | |
871 | $ git format-patch --cover-letter -o psuh/ master..psuh | |
872 | ---- | |
873 | ||
874 | The `--cover-letter` parameter tells `format-patch` to create a cover letter | |
875 | template for you. You will need to fill in the template before you're ready | |
876 | to send - but for now, the template will be next to your other patches. | |
877 | ||
878 | The `-o psuh/` parameter tells `format-patch` to place the patch files into a | |
879 | directory. This is useful because `git send-email` can take a directory and | |
880 | send out all the patches from there. | |
881 | ||
882 | `master..psuh` tells `format-patch` to generate patches for the difference | |
883 | between `master` and `psuh`. It will make one patch file per commit. After you | |
884 | run, you can go have a look at each of the patches with your favorite text | |
885 | editor and make sure everything looks alright; however, it's not recommended to | |
886 | make code fixups via the patch file. It's a better idea to make the change the | |
887 | normal way using `git rebase -i` or by adding a new commit than by modifying a | |
888 | patch. | |
889 | ||
890 | NOTE: Optionally, you can also use the `--rfc` flag to prefix your patch subject | |
891 | with ``[RFC PATCH]'' instead of ``[PATCH]''. RFC stands for ``request for | |
892 | comments'' and indicates that while your code isn't quite ready for submission, | |
893 | you'd like to begin the code review process. This can also be used when your | |
894 | patch is a proposal, but you aren't sure whether the community wants to solve | |
895 | the problem with that approach or not - to conduct a sort of design review. You | |
896 | may also see on the list patches marked ``WIP'' - this means they are incomplete | |
897 | but want reviewers to look at what they have so far. You can add this flag with | |
898 | `--subject-prefix=WIP`. | |
899 | ||
900 | Check and make sure that your patches and cover letter template exist in the | |
901 | directory you specified - you're nearly ready to send out your review! | |
902 | ||
5ef811ac | 903 | [[cover-letter]] |
76644e32 ES |
904 | === Preparing Email |
905 | ||
906 | In addition to an email per patch, the Git community also expects your patches | |
907 | to come with a cover letter, typically with a subject line [PATCH 0/x] (where | |
908 | x is the number of patches you're sending). Since you invoked `format-patch` | |
909 | with `--cover-letter`, you've already got a template ready. Open it up in your | |
910 | favorite editor. | |
911 | ||
912 | You should see a number of headers present already. Check that your `From:` | |
913 | header is correct. Then modify your `Subject:` to something which succinctly | |
914 | covers the purpose of your entire topic branch, for example: | |
915 | ||
916 | ---- | |
917 | Subject: [PATCH 0/7] adding the 'psuh' command | |
918 | ---- | |
919 | ||
920 | Make sure you retain the ``[PATCH 0/X]'' part; that's what indicates to the Git | |
921 | community that this email is the beginning of a review, and many reviewers | |
922 | filter their email for this type of flag. | |
923 | ||
924 | You'll need to add some extra parameters when you invoke `git send-email` to add | |
925 | the cover letter. | |
926 | ||
927 | Next you'll have to fill out the body of your cover letter. This is an important | |
928 | component of change submission as it explains to the community from a high level | |
929 | what you're trying to do, and why, in a way that's more apparent than just | |
930 | looking at your diff. Be sure to explain anything your diff doesn't make clear | |
931 | on its own. | |
932 | ||
933 | Here's an example body for `psuh`: | |
934 | ||
935 | ---- | |
936 | Our internal metrics indicate widespread interest in the command | |
937 | git-psuh - that is, many users are trying to use it, but finding it is | |
938 | unavailable, using some unknown workaround instead. | |
939 | ||
940 | The following handful of patches add the psuh command and implement some | |
941 | handy features on top of it. | |
942 | ||
943 | This patchset is part of the MyFirstContribution tutorial and should not | |
944 | be merged. | |
945 | ---- | |
946 | ||
947 | The template created by `git format-patch --cover-letter` includes a diffstat. | |
948 | This gives reviewers a summary of what they're in for when reviewing your topic. | |
949 | The one generated for `psuh` from the sample implementation looks like this: | |
950 | ||
951 | ---- | |
952 | Documentation/git-psuh.txt | 40 +++++++++++++++++++++ | |
953 | Makefile | 1 + | |
954 | builtin.h | 1 + | |
955 | builtin/psuh.c | 73 ++++++++++++++++++++++++++++++++++++++ | |
956 | git.c | 1 + | |
957 | t/t9999-psuh-tutorial.sh | 12 +++++++ | |
958 | 6 files changed, 128 insertions(+) | |
959 | create mode 100644 Documentation/git-psuh.txt | |
960 | create mode 100644 builtin/psuh.c | |
961 | create mode 100755 t/t9999-psuh-tutorial.sh | |
962 | ---- | |
963 | ||
964 | Finally, the letter will include the version of Git used to generate the | |
965 | patches. You can leave that string alone. | |
966 | ||
5ef811ac | 967 | [[sending-git-send-email]] |
76644e32 ES |
968 | === Sending Email |
969 | ||
970 | At this point you should have a directory `psuh/` which is filled with your | |
971 | patches and a cover letter. Time to mail it out! You can send it like this: | |
972 | ||
973 | ---- | |
974 | $ git send-email --to=target@example.com psuh/*.patch | |
975 | ---- | |
976 | ||
977 | NOTE: Check `git help send-email` for some other options which you may find | |
978 | valuable, such as changing the Reply-to address or adding more CC and BCC lines. | |
979 | ||
980 | NOTE: When you are sending a real patch, it will go to git@vger.kernel.org - but | |
981 | please don't send your patchset from the tutorial to the real mailing list! For | |
982 | now, you can send it to yourself, to make sure you understand how it will look. | |
983 | ||
984 | After you run the command above, you will be presented with an interactive | |
985 | prompt for each patch that's about to go out. This gives you one last chance to | |
986 | edit or quit sending something (but again, don't edit code this way). Once you | |
987 | press `y` or `a` at these prompts your emails will be sent! Congratulations! | |
988 | ||
989 | Awesome, now the community will drop everything and review your changes. (Just | |
990 | kidding - be patient!) | |
991 | ||
5ef811ac | 992 | [[v2-git-send-email]] |
76644e32 ES |
993 | === Sending v2 |
994 | ||
995 | Skip ahead to <<reviewing,Responding to Reviews>> for information on how to | |
996 | handle comments from reviewers. Continue this section when your topic branch is | |
997 | shaped the way you want it to look for your patchset v2. | |
998 | ||
999 | When you're ready with the next iteration of your patch, the process is fairly | |
1000 | similar. | |
1001 | ||
1002 | First, generate your v2 patches again: | |
1003 | ||
1004 | ---- | |
1005 | $ git format-patch -v2 --cover-letter -o psuh/ master..psuh | |
1006 | ---- | |
1007 | ||
1008 | This will add your v2 patches, all named like `v2-000n-my-commit-subject.patch`, | |
1009 | to the `psuh/` directory. You may notice that they are sitting alongside the v1 | |
1010 | patches; that's fine, but be careful when you are ready to send them. | |
1011 | ||
1012 | Edit your cover letter again. Now is a good time to mention what's different | |
1013 | between your last version and now, if it's something significant. You do not | |
1014 | need the exact same body in your second cover letter; focus on explaining to | |
1015 | reviewers the changes you've made that may not be as visible. | |
1016 | ||
1017 | You will also need to go and find the Message-Id of your previous cover letter. | |
1018 | You can either note it when you send the first series, from the output of `git | |
1019 | send-email`, or you can look it up on the | |
46c67492 | 1020 | https://lore.kernel.org/git[mailing list]. Find your cover letter in the |
76644e32 ES |
1021 | archives, click on it, then click "permalink" or "raw" to reveal the Message-Id |
1022 | header. It should match: | |
1023 | ||
1024 | ---- | |
1025 | Message-Id: <foo.12345.author@example.com> | |
1026 | ---- | |
1027 | ||
1028 | Your Message-Id is `<foo.12345.author@example.com>`. This example will be used | |
1029 | below as well; make sure to replace it with the correct Message-Id for your | |
1030 | **previous cover letter** - that is, if you're sending v2, use the Message-Id | |
1031 | from v1; if you're sending v3, use the Message-Id from v2. | |
1032 | ||
1033 | While you're looking at the email, you should also note who is CC'd, as it's | |
1034 | common practice in the mailing list to keep all CCs on a thread. You can add | |
1035 | these CC lines directly to your cover letter with a line like so in the header | |
1036 | (before the Subject line): | |
1037 | ||
1038 | ---- | |
1039 | CC: author@example.com, Othe R <other@example.com> | |
1040 | ---- | |
1041 | ||
1042 | Now send the emails again, paying close attention to which messages you pass in | |
1043 | to the command: | |
1044 | ||
1045 | ---- | |
1046 | $ git send-email --to=target@example.com | |
1047 | --in-reply-to="<foo.12345.author@example.com>" | |
1048 | psuh/v2* | |
1049 | ---- | |
1050 | ||
5ef811ac | 1051 | [[single-patch]] |
76644e32 ES |
1052 | === Bonus Chapter: One-Patch Changes |
1053 | ||
1054 | In some cases, your very small change may consist of only one patch. When that | |
1055 | happens, you only need to send one email. Your commit message should already be | |
1056 | meaningful and explain at a high level the purpose (what is happening and why) | |
1057 | of your patch, but if you need to supply even more context, you can do so below | |
1058 | the `---` in your patch. Take the example below, which was generated with `git | |
1059 | format-patch` on a single commit, and then edited to add the content between | |
1060 | the `---` and the diffstat. | |
1061 | ||
1062 | ---- | |
1063 | From 1345bbb3f7ac74abde040c12e737204689a72723 Mon Sep 17 00:00:00 2001 | |
1064 | From: A U Thor <author@example.com> | |
1065 | Date: Thu, 18 Apr 2019 15:11:02 -0700 | |
1066 | Subject: [PATCH] README: change the grammar | |
1067 | ||
1068 | I think it looks better this way. This part of the commit message will | |
1069 | end up in the commit-log. | |
1070 | ||
1071 | Signed-off-by: A U Thor <author@example.com> | |
1072 | --- | |
1073 | Let's have a wild discussion about grammar on the mailing list. This | |
1074 | part of my email will never end up in the commit log. Here is where I | |
1075 | can add additional context to the mailing list about my intent, outside | |
1076 | of the context of the commit log. This section was added after `git | |
1077 | format-patch` was run, by editing the patch file in a text editor. | |
1078 | ||
1079 | README.md | 2 +- | |
1080 | 1 file changed, 1 insertion(+), 1 deletion(-) | |
1081 | ||
1082 | diff --git a/README.md b/README.md | |
1083 | index 88f126184c..38da593a60 100644 | |
1084 | --- a/README.md | |
1085 | +++ b/README.md | |
1086 | @@ -3,7 +3,7 @@ | |
1087 | Git - fast, scalable, distributed revision control system | |
1088 | ========================================================= | |
1089 | ||
1090 | -Git is a fast, scalable, distributed revision control system with an | |
1091 | +Git is a fast, scalable, and distributed revision control system with an | |
1092 | unusually rich command set that provides both high-level operations | |
1093 | and full access to internals. | |
1094 | ||
1095 | -- | |
1096 | 2.21.0.392.gf8f6787159e-goog | |
1097 | ---- | |
1098 | ||
5ef811ac | 1099 | [[now-what]] |
76644e32 ES |
1100 | == My Patch Got Emailed - Now What? |
1101 | ||
1102 | [[reviewing]] | |
1103 | === Responding to Reviews | |
1104 | ||
1105 | After a few days, you will hopefully receive a reply to your patchset with some | |
1106 | comments. Woohoo! Now you can get back to work. | |
1107 | ||
1108 | It's good manners to reply to each comment, notifying the reviewer that you have | |
1109 | made the change requested, feel the original is better, or that the comment | |
1110 | inspired you to do something a new way which is superior to both the original | |
1111 | and the suggested change. This way reviewers don't need to inspect your v2 to | |
1112 | figure out whether you implemented their comment or not. | |
1113 | ||
1114 | If you are going to push back on a comment, be polite and explain why you feel | |
1115 | your original is better; be prepared that the reviewer may still disagree with | |
1116 | you, and the rest of the community may weigh in on one side or the other. As | |
1117 | with all code reviews, it's important to keep an open mind to doing something a | |
1118 | different way than you originally planned; other reviewers have a different | |
1119 | perspective on the project than you do, and may be thinking of a valid side | |
1120 | effect which had not occurred to you. It is always okay to ask for clarification | |
1121 | if you aren't sure why a change was suggested, or what the reviewer is asking | |
1122 | you to do. | |
1123 | ||
1124 | Make sure your email client has a plaintext email mode and it is turned on; the | |
1125 | Git list rejects HTML email. Please also follow the mailing list etiquette | |
1126 | outlined in the | |
1127 | https://kernel.googlesource.com/pub/scm/git/git/+/todo/MaintNotes[Maintainer's | |
1128 | Note], which are similar to etiquette rules in most open source communities | |
1129 | surrounding bottom-posting and inline replies. | |
1130 | ||
1131 | When you're making changes to your code, it is cleanest - that is, the resulting | |
1132 | commits are easiest to look at - if you use `git rebase -i` (interactive | |
1133 | rebase). Take a look at this | |
1134 | https://www.oreilly.com/library/view/git-pocket-guide/9781449327507/ch10.html[overview] | |
1135 | from O'Reilly. The general idea is to modify each commit which requires changes; | |
1136 | this way, instead of having a patch A with a mistake, a patch B which was fine | |
1137 | and required no upstream reviews in v1, and a patch C which fixes patch A for | |
1138 | v2, you can just ship a v2 with a correct patch A and correct patch B. This is | |
1139 | changing history, but since it's local history which you haven't shared with | |
1140 | anyone, that is okay for now! (Later, it may not make sense to do this; take a | |
1141 | look at the section below this one for some context.) | |
1142 | ||
5ef811ac | 1143 | [[after-approval]] |
76644e32 ES |
1144 | === After Review Approval |
1145 | ||
1146 | The Git project has four integration branches: `pu`, `next`, `master`, and | |
1147 | `maint`. Your change will be placed into `pu` fairly early on by the maintainer | |
1148 | while it is still in the review process; from there, when it is ready for wider | |
1149 | testing, it will be merged into `next`. Plenty of early testers use `next` and | |
1150 | may report issues. Eventually, changes in `next` will make it to `master`, | |
1151 | which is typically considered stable. Finally, when a new release is cut, | |
1152 | `maint` is used to base bugfixes onto. As mentioned at the beginning of this | |
1153 | document, you can read `Documents/SubmittingPatches` for some more info about | |
1154 | the use of the various integration branches. | |
1155 | ||
1156 | Back to now: your code has been lauded by the upstream reviewers. It is perfect. | |
1157 | It is ready to be accepted. You don't need to do anything else; the maintainer | |
1158 | will merge your topic branch to `next` and life is good. | |
1159 | ||
1160 | However, if you discover it isn't so perfect after this point, you may need to | |
1161 | take some special steps depending on where you are in the process. | |
1162 | ||
1163 | If the maintainer has announced in the "What's cooking in git.git" email that | |
1164 | your topic is marked for `next` - that is, that they plan to merge it to `next` | |
1165 | but have not yet done so - you should send an email asking the maintainer to | |
1166 | wait a little longer: "I've sent v4 of my series and you marked it for `next`, | |
1167 | but I need to change this and that - please wait for v5 before you merge it." | |
1168 | ||
1169 | If the topic has already been merged to `next`, rather than modifying your | |
1170 | patches with `git rebase -i`, you should make further changes incrementally - | |
1171 | that is, with another commit, based on top of the maintainer's topic branch as | |
1172 | detailed in https://github.com/gitster/git. Your work is still in the same topic | |
1173 | but is now incremental, rather than a wholesale rewrite of the topic branch. | |
1174 | ||
1175 | The topic branches in the maintainer's GitHub are mirrored in GitGitGadget, so | |
1176 | if you're sending your reviews out that way, you should be sure to open your PR | |
1177 | against the appropriate GitGitGadget/Git branch. | |
1178 | ||
1179 | If you're using `git send-email`, you can use it the same way as before, but you | |
1180 | should generate your diffs from `<topic>..<mybranch>` and base your work on | |
1181 | `<topic>` instead of `master`. |