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| My First Contribution to the Git Project | |
| ======================================== | |
| :sectanchors: | |
| [[summary]] | |
| == Summary | |
| This is a tutorial demonstrating the end-to-end workflow of creating a change to | |
| the Git tree, sending it for review, and making changes based on comments. | |
| [[prerequisites]] | |
| === Prerequisites | |
| This tutorial assumes you're already fairly familiar with using Git to manage | |
| source code. The Git workflow steps will largely remain unexplained. | |
| [[related-reading]] | |
| === Related Reading | |
| This tutorial aims to summarize the following documents, but the reader may find | |
| useful additional context: | |
| - `Documentation/SubmittingPatches` | |
| - `Documentation/howto/new-command.txt` | |
| [[getting-help]] | |
| === Getting Help | |
| If you get stuck, you can seek help in the following places. | |
| ==== [email protected] | |
| This is the main Git project mailing list where code reviews, version | |
| announcements, design discussions, and more take place. Those interested in | |
| contributing are welcome to post questions here. The Git list requires | |
| plain-text-only emails and prefers inline and bottom-posting when replying to | |
| mail; you will be CC'd in all replies to you. Optionally, you can subscribe to | |
| the list by sending an email to [email protected] with "subscribe git" | |
| in the body. The https://lore.kernel.org/git[archive] of this mailing list is | |
| available to view in a browser. | |
| ==== https://groups.google.com/forum/#!forum/git-mentoring[[email protected]] | |
| This mailing list is targeted to new contributors and was created as a place to | |
| post questions and receive answers outside of the public eye of the main list. | |
| Veteran contributors who are especially interested in helping mentor newcomers | |
| are present on the list. In order to avoid search indexers, group membership is | |
| required to view messages; anyone can join and no approval is required. | |
| ==== https://web.libera.chat/#git-devel[#git-devel] on Libera Chat | |
| This IRC channel is for conversations between Git contributors. If someone is | |
| currently online and knows the answer to your question, you can receive help | |
| in real time. Otherwise, you can read the | |
| https://colabti.org/irclogger/irclogger_logs/git-devel[scrollback] to see | |
| whether someone answered you. IRC does not allow offline private messaging, so | |
| if you try to private message someone and then log out of IRC, they cannot | |
| respond to you. It's better to ask your questions in the channel so that you | |
| can be answered if you disconnect and so that others can learn from the | |
| conversation. | |
| [[getting-started]] | |
| == Getting Started | |
| [[cloning]] | |
| === Clone the Git Repository | |
| Git is mirrored in a number of locations. Clone the repository from one of them; | |
| https://git-scm.com/downloads suggests one of the best places to clone from is | |
| the mirror on GitHub. | |
| ---- | |
| $ git clone https://github.com/git/git git | |
| $ cd git | |
| ---- | |
| [[dependencies]] | |
| === Installing Dependencies | |
| To build Git from source, you need to have a handful of dependencies installed | |
| on your system. For a hint of what's needed, you can take a look at | |
| `INSTALL`, paying close attention to the section about Git's dependencies on | |
| external programs and libraries. That document mentions a way to "test-drive" | |
| our freshly built Git without installing; that's the method we'll be using in | |
| this tutorial. | |
| Make sure that your environment has everything you need by building your brand | |
| new clone of Git from the above step: | |
| ---- | |
| $ make | |
| ---- | |
| NOTE: The Git build is parallelizable. `-j#` is not included above but you can | |
| use it as you prefer, here and elsewhere. | |
| [[identify-problem]] | |
| === Identify Problem to Solve | |
| //// | |
| Use + to indicate fixed-width here; couldn't get ` to work nicely with the | |
| quotes around "Pony Saying 'Um, Hello'". | |
| //// | |
| In this tutorial, we will add a new command, +git psuh+, short for ``Pony Saying | |
| `Um, Hello''' - a feature which has gone unimplemented despite a high frequency | |
| of invocation during users' typical daily workflow. | |
| (We've seen some other effort in this space with the implementation of popular | |
| commands such as `sl`.) | |
| [[setup-workspace]] | |
| === Set Up Your Workspace | |
| Let's start by making a development branch to work on our changes. Per | |
| `Documentation/SubmittingPatches`, since a brand new command is a new feature, | |
| it's fine to base your work on `master`. However, in the future for bugfixes, | |
| etc., you should check that document and base it on the appropriate branch. | |
| For the purposes of this document, we will base all our work on the `master` | |
| branch of the upstream project. Create the `psuh` branch you will use for | |
| development like so: | |
| ---- | |
| $ git checkout -b psuh origin/master | |
| ---- | |
| We'll make a number of commits here in order to demonstrate how to send a topic | |
| with multiple patches up for review simultaneously. | |
| [[code-it-up]] | |
| == Code It Up! | |
| NOTE: A reference implementation can be found at | |
| https://github.com/nasamuffin/git/tree/psuh. | |
| [[add-new-command]] | |
| === Adding a New Command | |
| Lots of the subcommands are written as builtins, which means they are | |
| implemented in C and compiled into the main `git` executable. Implementing the | |
| very simple `psuh` command as a built-in will demonstrate the structure of the | |
| codebase, the internal API, and the process of working together as a contributor | |
| with the reviewers and maintainer to integrate this change into the system. | |
| Built-in subcommands are typically implemented in a function named "cmd_" | |
| followed by the name of the subcommand, in a source file named after the | |
| subcommand and contained within `builtin/`. So it makes sense to implement your | |
| command in `builtin/psuh.c`. Create that file, and within it, write the entry | |
| point for your command in a function matching the style and signature: | |
| ---- | |
| int cmd_psuh(int argc, const char **argv, const char *prefix) | |
| ---- | |
| We'll also need to add the declaration of psuh; open up `builtin.h`, find the | |
| declaration for `cmd_pull`, and add a new line for `psuh` immediately before it, | |
| in order to keep the declarations alphabetically sorted: | |
| ---- | |
| int cmd_psuh(int argc, const char **argv, const char *prefix); | |
| ---- | |
| Be sure to `#include "builtin.h"` in your `psuh.c`. | |
| Go ahead and add some throwaway printf to that function. This is a decent | |
| starting point as we can now add build rules and register the command. | |
| NOTE: Your throwaway text, as well as much of the text you will be adding over | |
| the course of this tutorial, is user-facing. That means it needs to be | |
| localizable. Take a look at `po/README` under "Marking strings for translation". | |
| Throughout the tutorial, we will mark strings for translation as necessary; you | |
| should also do so when writing your user-facing commands in the future. | |
| ---- | |
| int cmd_psuh(int argc, const char **argv, const char *prefix) | |
| { | |
| printf(_("Pony saying hello goes here.\n")); | |
| return 0; | |
| } | |
| ---- | |
| Let's try to build it. Open `Makefile`, find where `builtin/pull.o` is added | |
| to `BUILTIN_OBJS`, and add `builtin/psuh.o` in the same way next to it in | |
| alphabetical order. Once you've done so, move to the top-level directory and | |
| build simply with `make`. Also add the `DEVELOPER=1` variable to turn on | |
| some additional warnings: | |
| ---- | |
| $ echo DEVELOPER=1 >config.mak | |
| $ make | |
| ---- | |
| NOTE: When you are developing the Git project, it's preferred that you use the | |
| `DEVELOPER` flag; if there's some reason it doesn't work for you, you can turn | |
| it off, but it's a good idea to mention the problem to the mailing list. | |
| Great, now your new command builds happily on its own. But nobody invokes it. | |
| Let's change that. | |
| The list of commands lives in `git.c`. We can register a new command by adding | |
| a `cmd_struct` to the `commands[]` array. `struct cmd_struct` takes a string | |
| with the command name, a function pointer to the command implementation, and a | |
| setup option flag. For now, let's keep mimicking `push`. Find the line where | |
| `cmd_push` is registered, copy it, and modify it for `cmd_psuh`, placing the new | |
| line in alphabetical order (immediately before `cmd_pull`). | |
| The options are documented in `builtin.h` under "Adding a new built-in." Since | |
| we hope to print some data about the user's current workspace context later, | |
| we need a Git directory, so choose `RUN_SETUP` as your only option. | |
| Go ahead and build again. You should see a clean build, so let's kick the tires | |
| and see if it works. There's a binary you can use to test with in the | |
| `bin-wrappers` directory. | |
| ---- | |
| $ ./bin-wrappers/git psuh | |
| ---- | |
| Check it out! You've got a command! Nice work! Let's commit this. | |
| `git status` reveals modified `Makefile`, `builtin.h`, and `git.c` as well as | |
| untracked `builtin/psuh.c` and `git-psuh`. First, let's take care of the binary, | |
| which should be ignored. Open `.gitignore` in your editor, find `/git-pull`, and | |
| add an entry for your new command in alphabetical order: | |
| ---- | |
| ... | |
| /git-prune-packed | |
| /git-psuh | |
| /git-pull | |
| /git-push | |
| /git-quiltimport | |
| /git-range-diff | |
| ... | |
| ---- | |
| Checking `git status` again should show that `git-psuh` has been removed from | |
| the untracked list and `.gitignore` has been added to the modified list. Now we | |
| can stage and commit: | |
| ---- | |
| $ git add Makefile builtin.h builtin/psuh.c git.c .gitignore | |
| $ git commit -s | |
| ---- | |
| You will be presented with your editor in order to write a commit message. Start | |
| the commit with a 50-column or less subject line, including the name of the | |
| component you're working on, followed by a blank line (always required) and then | |
| the body of your commit message, which should provide the bulk of the context. | |
| Remember to be explicit and provide the "Why" of your change, especially if it | |
| couldn't easily be understood from your diff. When editing your commit message, | |
| don't remove the `Signed-off-by` trailer which was added by `-s` above. | |
| ---- | |
| psuh: add a built-in by popular demand | |
| Internal metrics indicate this is a command many users expect to be | |
| present. So here's an implementation to help drive customer | |
| satisfaction and engagement: a pony which doubtfully greets the user, | |
| or, a Pony Saying "Um, Hello" (PSUH). | |
| This commit message is intentionally formatted to 72 columns per line, | |
| starts with a single line as "commit message subject" that is written as | |
| if to command the codebase to do something (add this, teach a command | |
| that). The body of the message is designed to add information about the | |
| commit that is not readily deduced from reading the associated diff, | |
| such as answering the question "why?". | |
| Signed-off-by: A U Thor <[email protected]> | |
| ---- | |
| Go ahead and inspect your new commit with `git show`. "psuh:" indicates you | |
| have modified mainly the `psuh` command. The subject line gives readers an idea | |
| of what you've changed. The sign-off line (`-s`) indicates that you agree to | |
| the Developer's Certificate of Origin 1.1 (see the | |
| `Documentation/SubmittingPatches` +++[[dco]]+++ header). | |
| For the remainder of the tutorial, the subject line only will be listed for the | |
| sake of brevity. However, fully-fleshed example commit messages are available | |
| on the reference implementation linked at the top of this document. | |
| [[implementation]] | |
| === Implementation | |
| It's probably useful to do at least something besides printing out a string. | |
| Let's start by having a look at everything we get. | |
| Modify your `cmd_psuh` implementation to dump the args you're passed, keeping | |
| existing `printf()` calls in place: | |
| ---- | |
| int i; | |
| ... | |
| printf(Q_("Your args (there is %d):\n", | |
| "Your args (there are %d):\n", | |
| argc), | |
| argc); | |
| for (i = 0; i < argc; i++) | |
| printf("%d: %s\n", i, argv[i]); | |
| printf(_("Your current working directory:\n<top-level>%s%s\n"), | |
| prefix ? "/" : "", prefix ? prefix : ""); | |
| ---- | |
| Build and try it. As you may expect, there's pretty much just whatever we give | |
| on the command line, including the name of our command. (If `prefix` is empty | |
| for you, try `cd Documentation/ && ../bin-wrappers/git psuh`). That's not so | |
| helpful. So what other context can we get? | |
| Add a line to `#include "config.h"`. Then, add the following bits to the | |
| function body: | |
| ---- | |
| const char *cfg_name; | |
| ... | |
| git_config(git_default_config, NULL); | |
| if (git_config_get_string_tmp("user.name", &cfg_name) > 0) | |
| printf(_("No name is found in config\n")); | |
| else | |
| printf(_("Your name: %s\n"), cfg_name); | |
| ---- | |
| `git_config()` will grab the configuration from config files known to Git and | |
| apply standard precedence rules. `git_config_get_string_tmp()` will look up | |
| a specific key ("user.name") and give you the value. There are a number of | |
| single-key lookup functions like this one; you can see them all (and more info | |
| about how to use `git_config()`) in `Documentation/technical/api-config.txt`. | |
| You should see that the name printed matches the one you see when you run: | |
| ---- | |
| $ git config --get user.name | |
| ---- | |
| Great! Now we know how to check for values in the Git config. Let's commit this | |
| too, so we don't lose our progress. | |
| ---- | |
| $ git add builtin/psuh.c | |
| $ git commit -sm "psuh: show parameters & config opts" | |
| ---- | |
| NOTE: Again, the above is for sake of brevity in this tutorial. In a real change | |
| you should not use `-m` but instead use the editor to write a meaningful | |
| message. | |
| Still, it'd be nice to know what the user's working context is like. Let's see | |
| if we can print the name of the user's current branch. We can mimic the | |
| `git status` implementation; the printer is located in `wt-status.c` and we can | |
| see that the branch is held in a `struct wt_status`. | |
| `wt_status_print()` gets invoked by `cmd_status()` in `builtin/commit.c`. | |
| Looking at that implementation we see the status config being populated like so: | |
| ---- | |
| status_init_config(&s, git_status_config); | |
| ---- | |
| But as we drill down, we can find that `status_init_config()` wraps a call | |
| to `git_config()`. Let's modify the code we wrote in the previous commit. | |
| Be sure to include the header to allow you to use `struct wt_status`: | |
| ---- | |
| #include "wt-status.h" | |
| ---- | |
| Then modify your `cmd_psuh` implementation to declare your `struct wt_status`, | |
| prepare it, and print its contents: | |
| ---- | |
| struct wt_status status; | |
| ... | |
| wt_status_prepare(the_repository, &status); | |
| git_config(git_default_config, &status); | |
| ... | |
| printf(_("Your current branch: %s\n"), status.branch); | |
| ---- | |
| Run it again. Check it out - here's the (verbose) name of your current branch! | |
| Let's commit this as well. | |
| ---- | |
| $ git add builtin/psuh.c | |
| $ git commit -sm "psuh: print the current branch" | |
| ---- | |
| Now let's see if we can get some info about a specific commit. | |
| Luckily, there are some helpers for us here. `commit.h` has a function called | |
| `lookup_commit_reference_by_name` to which we can simply provide a hardcoded | |
| string; `pretty.h` has an extremely handy `pp_commit_easy()` call which doesn't | |
| require a full format object to be passed. | |
| Add the following includes: | |
| ---- | |
| #include "commit.h" | |
| #include "pretty.h" | |
| ---- | |
| Then, add the following lines within your implementation of `cmd_psuh()` near | |
| the declarations and the logic, respectively. | |
| ---- | |
| struct commit *c = NULL; | |
| struct strbuf commitline = STRBUF_INIT; | |
| ... | |
| c = lookup_commit_reference_by_name("origin/master"); | |
| if (c != NULL) { | |
| pp_commit_easy(CMIT_FMT_ONELINE, c, &commitline); | |
| printf(_("Current commit: %s\n"), commitline.buf); | |
| } | |
| ---- | |
| The `struct strbuf` provides some safety belts to your basic `char*`, one of | |
| which is a length member to prevent buffer overruns. It needs to be initialized | |
| nicely with `STRBUF_INIT`. Keep it in mind when you need to pass around `char*`. | |
| `lookup_commit_reference_by_name` resolves the name you pass it, so you can play | |
| with the value there and see what kind of things you can come up with. | |
| `pp_commit_easy` is a convenience wrapper in `pretty.h` that takes a single | |
| format enum shorthand, rather than an entire format struct. It then | |
| pretty-prints the commit according to that shorthand. These are similar to the | |
| formats available with `--pretty=FOO` in many Git commands. | |
| Build it and run, and if you're using the same name in the example, you should | |
| see the subject line of the most recent commit in `origin/master` that you know | |
| about. Neat! Let's commit that as well. | |
| ---- | |
| $ git add builtin/psuh.c | |
| $ git commit -sm "psuh: display the top of origin/master" | |
| ---- | |
| [[add-documentation]] | |
| === Adding Documentation | |
| Awesome! You've got a fantastic new command that you're ready to share with the | |
| community. But hang on just a minute - this isn't very user-friendly. Run the | |
| following: | |
| ---- | |
| $ ./bin-wrappers/git help psuh | |
| ---- | |
| Your new command is undocumented! Let's fix that. | |
| Take a look at `Documentation/git-*.txt`. These are the manpages for the | |
| subcommands that Git knows about. You can open these up and take a look to get | |
| acquainted with the format, but then go ahead and make a new file | |
| `Documentation/git-psuh.txt`. Like with most of the documentation in the Git | |
| project, help pages are written with AsciiDoc (see CodingGuidelines, "Writing | |
| Documentation" section). Use the following template to fill out your own | |
| manpage: | |
| // Surprisingly difficult to embed AsciiDoc source within AsciiDoc. | |
| [listing] | |
| .... | |
| git-psuh(1) | |
| =========== | |
| NAME | |
| ---- | |
| git-psuh - Delight users' typo with a shy horse | |
| SYNOPSIS | |
| -------- | |
| [verse] | |
| 'git-psuh [<arg>...]' | |
| DESCRIPTION | |
| ----------- | |
| ... | |
| OPTIONS[[OPTIONS]] | |
| ------------------ | |
| ... | |
| OUTPUT | |
| ------ | |
| ... | |
| GIT | |
| --- | |
| Part of the linkgit:git[1] suite | |
| .... | |
| The most important pieces of this to note are the file header, underlined by =, | |
| the NAME section, and the SYNOPSIS, which would normally contain the grammar if | |
| your command took arguments. Try to use well-established manpage headers so your | |
| documentation is consistent with other Git and UNIX manpages; this makes life | |
| easier for your user, who can skip to the section they know contains the | |
| information they need. | |
| NOTE: Before trying to build the docs, make sure you have the package `asciidoc` | |
| installed. | |
| Now that you've written your manpage, you'll need to build it explicitly. We | |
| convert your AsciiDoc to troff which is man-readable like so: | |
| ---- | |
| $ make all doc | |
| $ man Documentation/git-psuh.1 | |
| ---- | |
| or | |
| ---- | |
| $ make -C Documentation/ git-psuh.1 | |
| $ man Documentation/git-psuh.1 | |
| ---- | |
| While this isn't as satisfying as running through `git help`, you can at least | |
| check that your help page looks right. | |
| You can also check that the documentation coverage is good (that is, the project | |
| sees that your command has been implemented as well as documented) by running | |
| `make check-docs` from the top-level. | |
| Go ahead and commit your new documentation change. | |
| [[add-usage]] | |
| === Adding Usage Text | |
| Try and run `./bin-wrappers/git psuh -h`. Your command should crash at the end. | |
| That's because `-h` is a special case which your command should handle by | |
| printing usage. | |
| Take a look at `Documentation/technical/api-parse-options.txt`. This is a handy | |
| tool for pulling out options you need to be able to handle, and it takes a | |
| usage string. | |
| In order to use it, we'll need to prepare a NULL-terminated array of usage | |
| strings and a `builtin_psuh_options` array. | |
| Add a line to `#include "parse-options.h"`. | |
| At global scope, add your array of usage strings: | |
| ---- | |
| static const char * const psuh_usage[] = { | |
| N_("git psuh [<arg>...]"), | |
| NULL, | |
| }; | |
| ---- | |
| Then, within your `cmd_psuh()` implementation, we can declare and populate our | |
| `option` struct. Ours is pretty boring but you can add more to it if you want to | |
| explore `parse_options()` in more detail: | |
| ---- | |
| struct option options[] = { | |
| OPT_END() | |
| }; | |
| ---- | |
| Finally, before you print your args and prefix, add the call to | |
| `parse-options()`: | |
| ---- | |
| argc = parse_options(argc, argv, prefix, options, psuh_usage, 0); | |
| ---- | |
| This call will modify your `argv` parameter. It will strip the options you | |
| specified in `options` from `argv` and the locations pointed to from `options` | |
| entries will be updated. Be sure to replace your `argc` with the result from | |
| `parse_options()`, or you will be confused if you try to parse `argv` later. | |
| It's worth noting the special argument `--`. As you may be aware, many Unix | |
| commands use `--` to indicate "end of named parameters" - all parameters after | |
| the `--` are interpreted merely as positional arguments. (This can be handy if | |
| you want to pass as a parameter something which would usually be interpreted as | |
| a flag.) `parse_options()` will terminate parsing when it reaches `--` and give | |
| you the rest of the options afterwards, untouched. | |
| Now that you have a usage hint, you can teach Git how to show it in the general | |
| command list shown by `git help git` or `git help -a`, which is generated from | |
| `command-list.txt`. Find the line for 'git-pull' so you can add your 'git-psuh' | |
| line above it in alphabetical order. Now, we can add some attributes about the | |
| command which impacts where it shows up in the aforementioned help commands. The | |
| top of `command-list.txt` shares some information about what each attribute | |
| means; in those help pages, the commands are sorted according to these | |
| attributes. `git psuh` is user-facing, or porcelain - so we will mark it as | |
| "mainporcelain". For "mainporcelain" commands, the comments at the top of | |
| `command-list.txt` indicate we can also optionally add an attribute from another | |
| list; since `git psuh` shows some information about the user's workspace but | |
| doesn't modify anything, let's mark it as "info". Make sure to keep your | |
| attributes in the same style as the rest of `command-list.txt` using spaces to | |
| align and delineate them: | |
| ---- | |
| git-prune-packed plumbingmanipulators | |
| git-psuh mainporcelain info | |
| git-pull mainporcelain remote | |
| git-push mainporcelain remote | |
| ---- | |
| Build again. Now, when you run with `-h`, you should see your usage printed and | |
| your command terminated before anything else interesting happens. Great! | |
| Go ahead and commit this one, too. | |
| [[testing]] | |
| == Testing | |
| It's important to test your code - even for a little toy command like this one. | |
| Moreover, your patch won't be accepted into the Git tree without tests. Your | |
| tests should: | |
| * Illustrate the current behavior of the feature | |
| * Prove the current behavior matches the expected behavior | |
| * Ensure the externally-visible behavior isn't broken in later changes | |
| So let's write some tests. | |
| Related reading: `t/README` | |
| [[overview-test-structure]] | |
| === Overview of Testing Structure | |
| The tests in Git live in `t/` and are named with a 4-digit decimal number using | |
| the schema shown in the Naming Tests section of `t/README`. | |
| [[write-new-test]] | |
| === Writing Your Test | |
| Since this a toy command, let's go ahead and name the test with t9999. However, | |
| as many of the family/subcmd combinations are full, best practice seems to be | |
| to find a command close enough to the one you've added and share its naming | |
| space. | |
| Create a new file `t/t9999-psuh-tutorial.sh`. Begin with the header as so (see | |
| "Writing Tests" and "Source 'test-lib.sh'" in `t/README`): | |
| ---- | |
| #!/bin/sh | |
| test_description='git-psuh test | |
| This test runs git-psuh and makes sure it does not crash.' | |
| . ./test-lib.sh | |
| ---- | |
| Tests are framed inside of a `test_expect_success` in order to output TAP | |
| formatted results. Let's make sure that `git psuh` doesn't exit poorly and does | |
| mention the right animal somewhere: | |
| ---- | |
| test_expect_success 'runs correctly with no args and good output' ' | |
| git psuh >actual && | |
| grep Pony actual | |
| ' | |
| ---- | |
| Indicate that you've run everything you wanted by adding the following at the | |
| bottom of your script: | |
| ---- | |
| test_done | |
| ---- | |
| Make sure you mark your test script executable: | |
| ---- | |
| $ chmod +x t/t9999-psuh-tutorial.sh | |
| ---- | |
| You can get an idea of whether you created your new test script successfully | |
| by running `make -C t test-lint`, which will check for things like test number | |
| uniqueness, executable bit, and so on. | |
| [[local-test]] | |
| === Running Locally | |
| Let's try and run locally: | |
| ---- | |
| $ make | |
| $ cd t/ && prove t9999-psuh-tutorial.sh | |
| ---- | |
| You can run the full test suite and ensure `git-psuh` didn't break anything: | |
| ---- | |
| $ cd t/ | |
| $ prove -j$(nproc) --shuffle t[0-9]*.sh | |
| ---- | |
| NOTE: You can also do this with `make test` or use any testing harness which can | |
| speak TAP. `prove` can run concurrently. `shuffle` randomizes the order the | |
| tests are run in, which makes them resilient against unwanted inter-test | |
| dependencies. `prove` also makes the output nicer. | |
| Go ahead and commit this change, as well. | |
| [[ready-to-share]] | |
| == Getting Ready to Share: Anatomy of a Patch Series | |
| You may have noticed already that the Git project performs its code reviews via | |
| emailed patches, which are then applied by the maintainer when they are ready | |
| and approved by the community. The Git project does not accept contributions from | |
| pull requests, and the patches emailed for review need to be formatted a | |
| specific way. | |
| :patch-series: https://lore.kernel.org/git/[email protected]/ | |
| :lore: https://lore.kernel.org/git/ | |
| Before taking a look at how to convert your commits into emailed patches, | |
| let's analyze what the end result, a "patch series", looks like. Here is an | |
| {patch-series}[example] of the summary view for a patch series on the web interface of | |
| the {lore}[Git mailing list archive]: | |
| ---- | |
| 2022-02-18 18:40 [PATCH 0/3] libify reflog John Cai via GitGitGadget | |
| 2022-02-18 18:40 ` [PATCH 1/3] reflog: libify delete reflog function and helpers John Cai via GitGitGadget | |
| 2022-02-18 19:10 ` Ævar Arnfjörð Bjarmason [this message] | |
| 2022-02-18 19:39 ` Taylor Blau | |
| 2022-02-18 19:48 ` Ævar Arnfjörð Bjarmason | |
| 2022-02-18 19:35 ` Taylor Blau | |
| 2022-02-21 1:43 ` John Cai | |
| 2022-02-21 1:50 ` Taylor Blau | |
| 2022-02-23 19:50 ` John Cai | |
| 2022-02-18 20:00 ` // other replies elided | |
| 2022-02-18 18:40 ` [PATCH 2/3] reflog: call reflog_delete from reflog.c John Cai via GitGitGadget | |
| 2022-02-18 19:15 ` Ævar Arnfjörð Bjarmason | |
| 2022-02-18 20:26 ` Junio C Hamano | |
| 2022-02-18 18:40 ` [PATCH 3/3] stash: call reflog_delete from reflog.c John Cai via GitGitGadget | |
| 2022-02-18 19:20 ` Ævar Arnfjörð Bjarmason | |
| 2022-02-19 0:21 ` Taylor Blau | |
| 2022-02-22 2:36 ` John Cai | |
| 2022-02-22 10:51 ` Ævar Arnfjörð Bjarmason | |
| 2022-02-18 19:29 ` [PATCH 0/3] libify reflog Ævar Arnfjörð Bjarmason | |
| 2022-02-22 18:30 ` [PATCH v2 0/3] libify reflog John Cai via GitGitGadget | |
| 2022-02-22 18:30 ` [PATCH v2 1/3] stash: add test to ensure reflog --rewrite --updatref behavior John Cai via GitGitGadget | |
| 2022-02-23 8:54 ` Ævar Arnfjörð Bjarmason | |
| 2022-02-23 21:27 ` Junio C Hamano | |
| // continued | |
| ---- | |
| We can note a few things: | |
| - Each commit is sent as a separate email, with the commit message title as | |
| subject, prefixed with "[PATCH _i_/_n_]" for the _i_-th commit of an | |
| _n_-commit series. | |
| - Each patch is sent as a reply to an introductory email called the _cover | |
| letter_ of the series, prefixed "[PATCH 0/_n_]". | |
| - Subsequent iterations of the patch series are labelled "PATCH v2", "PATCH | |
| v3", etc. in place of "PATCH". For example, "[PATCH v2 1/3]" would be the first of | |
| three patches in the second iteration. Each iteration is sent with a new cover | |
| letter (like "[PATCH v2 0/3]" above), itself a reply to the cover letter of the | |
| previous iteration (more on that below). | |
| NOTE: A single-patch topic is sent with "[PATCH]", "[PATCH v2]", etc. without | |
| _i_/_n_ numbering (in the above thread overview, no single-patch topic appears, | |
| though). | |
| [[cover-letter]] | |
| === The cover letter | |
| In addition to an email per patch, the Git community also expects your patches | |
| to come with a cover letter. This is an important component of change | |
| submission as it explains to the community from a high level what you're trying | |
| to do, and why, in a way that's more apparent than just looking at your | |
| patches. | |
| The title of your cover letter should be something which succinctly covers the | |
| purpose of your entire topic branch. It's often in the imperative mood, just | |
| like our commit message titles. Here is how we'll title our series: | |
| --- | |
| Add the 'psuh' command | |
| --- | |
| The body of the cover letter is used to give additional context to reviewers. | |
| Be sure to explain anything your patches don't make clear on their own, but | |
| remember that since the cover letter is not recorded in the commit history, | |
| anything that might be useful to future readers of the repository's history | |
| should also be in your commit messages. | |
| Here's an example body for `psuh`: | |
| ---- | |
| Our internal metrics indicate widespread interest in the command | |
| git-psuh - that is, many users are trying to use it, but finding it is | |
| unavailable, using some unknown workaround instead. | |
| The following handful of patches add the psuh command and implement some | |
| handy features on top of it. | |
| This patchset is part of the MyFirstContribution tutorial and should not | |
| be merged. | |
| ---- | |
| At this point the tutorial diverges, in order to demonstrate two | |
| different methods of formatting your patchset and getting it reviewed. | |
| The first method to be covered is GitGitGadget, which is useful for those | |
| already familiar with GitHub's common pull request workflow. This method | |
| requires a GitHub account. | |
| The second method to be covered is `git send-email`, which can give slightly | |
| more fine-grained control over the emails to be sent. This method requires some | |
| setup which can change depending on your system and will not be covered in this | |
| tutorial. | |
| Regardless of which method you choose, your engagement with reviewers will be | |
| the same; the review process will be covered after the sections on GitGitGadget | |
| and `git send-email`. | |
| [[howto-ggg]] | |
| == Sending Patches via GitGitGadget | |
| One option for sending patches is to follow a typical pull request workflow and | |
| send your patches out via GitGitGadget. GitGitGadget is a tool created by | |
| Johannes Schindelin to make life as a Git contributor easier for those used to | |
| the GitHub PR workflow. It allows contributors to open pull requests against its | |
| mirror of the Git project, and does some magic to turn the PR into a set of | |
| emails and send them out for you. It also runs the Git continuous integration | |
| suite for you. It's documented at http://gitgitgadget.github.io. | |
| [[create-fork]] | |
| === Forking `git/git` on GitHub | |
| Before you can send your patch off to be reviewed using GitGitGadget, you will | |
| need to fork the Git project and upload your changes. First thing - make sure | |
| you have a GitHub account. | |
| Head to the https://github.com/git/git[GitHub mirror] and look for the Fork | |
| button. Place your fork wherever you deem appropriate and create it. | |
| [[upload-to-fork]] | |
| === Uploading to Your Own Fork | |
| To upload your branch to your own fork, you'll need to add the new fork as a | |
| remote. You can use `git remote -v` to show the remotes you have added already. | |
| From your new fork's page on GitHub, you can press "Clone or download" to get | |
| the URL; then you need to run the following to add, replacing your own URL and | |
| remote name for the examples provided: | |
| ---- | |
| $ git remote add remotename [email protected]:remotename/git.git | |
| ---- | |
| or to use the HTTPS URL: | |
| ---- | |
| $ git remote add remotename https://github.com/remotename/git/.git | |
| ---- | |
| Run `git remote -v` again and you should see the new remote showing up. | |
| `git fetch remotename` (with the real name of your remote replaced) in order to | |
| get ready to push. | |
| Next, double-check that you've been doing all your development in a new branch | |
| by running `git branch`. If you didn't, now is a good time to move your new | |
| commits to their own branch. | |
| As mentioned briefly at the beginning of this document, we are basing our work | |
| on `master`, so go ahead and update as shown below, or using your preferred | |
| workflow. | |
| ---- | |
| $ git checkout master | |
| $ git pull -r | |
| $ git rebase master psuh | |
| ---- | |
| Finally, you're ready to push your new topic branch! (Due to our branch and | |
| command name choices, be careful when you type the command below.) | |
| ---- | |
| $ git push remotename psuh | |
| ---- | |
| Now you should be able to go and check out your newly created branch on GitHub. | |
| [[send-pr-ggg]] | |
| === Sending a PR to GitGitGadget | |
| In order to have your code tested and formatted for review, you need to start by | |
| opening a Pull Request against `gitgitgadget/git`. Head to | |
| https://github.com/gitgitgadget/git and open a PR either with the "New pull | |
| request" button or the convenient "Compare & pull request" button that may | |
| appear with the name of your newly pushed branch. | |
| Review the PR's title and description, as they're used by GitGitGadget | |
| respectively as the subject and body of the cover letter for your change. Refer | |
| to <<cover-letter,"The cover letter">> above for advice on how to title your | |
| submission and what content to include in the description. | |
| NOTE: For single-patch contributions, your commit message should already be | |
| meaningful and explain at a high level the purpose (what is happening and why) | |
| of your patch, so you usually do not need any additional context. In that case, | |
| remove the PR description that GitHub automatically generates from your commit | |
| message (your PR description should be empty). If you do need to supply even | |
| more context, you can do so in that space and it will be appended to the email | |
| that GitGitGadget will send, between the three-dash line and the diffstat | |
| (see <<single-patch,Bonus Chapter: One-Patch Changes>> for how this looks once | |
| submitted). | |
| When you're happy, submit your pull request. | |
| [[run-ci-ggg]] | |
| === Running CI and Getting Ready to Send | |
| If it's your first time using GitGitGadget (which is likely, as you're using | |
| this tutorial) then someone will need to give you permission to use the tool. | |
| As mentioned in the GitGitGadget documentation, you just need someone who | |
| already uses it to comment on your PR with `/allow <username>`. GitGitGadget | |
| will automatically run your PRs through the CI even without the permission given | |
| but you will not be able to `/submit` your changes until someone allows you to | |
| use the tool. | |
| NOTE: You can typically find someone who can `/allow` you on GitGitGadget by | |
| either examining recent pull requests where someone has been granted `/allow` | |
| (https://github.com/gitgitgadget/git/pulls?utf8=%E2%9C%93&q=is%3Apr+is%3Aopen+%22%2Fallow%22[Search: | |
| is:pr is:open "/allow"]), in which case both the author and the person who | |
| granted the `/allow` can now `/allow` you, or by inquiring on the | |
| https://web.libera.chat/#git-devel[#git-devel] IRC channel on Libera Chat | |
| linking your pull request and asking for someone to `/allow` you. | |
| If the CI fails, you can update your changes with `git rebase -i` and push your | |
| branch again: | |
| ---- | |
| $ git push -f remotename psuh | |
| ---- | |
| In fact, you should continue to make changes this way up until the point when | |
| your patch is accepted into `next`. | |
| //// | |
| TODO https://github.com/gitgitgadget/gitgitgadget/issues/83 | |
| It'd be nice to be able to verify that the patch looks good before sending it | |
| to everyone on Git mailing list. | |
| [[check-work-ggg]] | |
| === Check Your Work | |
| //// | |
| [[send-mail-ggg]] | |
| === Sending Your Patches | |
| Now that your CI is passing and someone has granted you permission to use | |
| GitGitGadget with the `/allow` command, sending out for review is as simple as | |
| commenting on your PR with `/submit`. | |
| [[responding-ggg]] | |
| === Updating With Comments | |
| Skip ahead to <<reviewing,Responding to Reviews>> for information on how to | |
| reply to review comments you will receive on the mailing list. | |
| Once you have your branch again in the shape you want following all review | |
| comments, you can submit again: | |
| ---- | |
| $ git push -f remotename psuh | |
| ---- | |
| Next, go look at your pull request against GitGitGadget; you should see the CI | |
| has been kicked off again. Now while the CI is running is a good time for you | |
| to modify your description at the top of the pull request thread; it will be | |
| used again as the cover letter. You should use this space to describe what | |
| has changed since your previous version, so that your reviewers have some idea | |
| of what they're looking at. When the CI is done running, you can comment once | |
| more with `/submit` - GitGitGadget will automatically add a v2 mark to your | |
| changes. | |
| [[howto-git-send-email]] | |
| == Sending Patches with `git send-email` | |
| If you don't want to use GitGitGadget, you can also use Git itself to mail your | |
| patches. Some benefits of using Git this way include finer grained control of | |
| subject line (for example, being able to use the tag [RFC PATCH] in the subject) | |
| and being able to send a ``dry run'' mail to yourself to ensure it all looks | |
| good before going out to the list. | |
| [[setup-git-send-email]] | |
| === Prerequisite: Setting Up `git send-email` | |
| Configuration for `send-email` can vary based on your operating system and email | |
| provider, and so will not be covered in this tutorial, beyond stating that in | |
| many distributions of Linux, `git-send-email` is not packaged alongside the | |
| typical `git` install. You may need to install this additional package; there | |
| are a number of resources online to help you do so. You will also need to | |
| determine the right way to configure it to use your SMTP server; again, as this | |
| configuration can change significantly based on your system and email setup, it | |
| is out of scope for the context of this tutorial. | |
| [[format-patch]] | |
| === Preparing Initial Patchset | |
| Sending emails with Git is a two-part process; before you can prepare the emails | |
| themselves, you'll need to prepare the patches. Luckily, this is pretty simple: | |
| ---- | |
| $ git format-patch --cover-letter -o psuh/ --base=auto psuh@{u}..psuh | |
| ---- | |
| . The `--cover-letter` option tells `format-patch` to create a | |
| cover letter template for you. You will need to fill in the | |
| template before you're ready to send - but for now, the template | |
| will be next to your other patches. | |
| . The `-o psuh/` option tells `format-patch` to place the patch | |
| files into a directory. This is useful because `git send-email` | |
| can take a directory and send out all the patches from there. | |
| . The `--base=auto` option tells the command to record the "base | |
| commit", on which the recipient is expected to apply the patch | |
| series. The `auto` value will cause `format-patch` to compute | |
| the base commit automatically, which is the merge base of tip | |
| commit of the remote-tracking branch and the specified revision | |
| range. | |
| . The `psuh@{u}..psuh` option tells `format-patch` to generate | |
| patches for the commits you created on the `psuh` branch since it | |
| forked from its upstream (which is `origin/master` if you | |
| followed the example in the "Set up your workspace" section). If | |
| you are already on the `psuh` branch, you can just say `@{u}`, | |
| which means "commits on the current branch since it forked from | |
| its upstream", which is the same thing. | |
| The command will make one patch file per commit. After you | |
| run, you can go have a look at each of the patches with your favorite text | |
| editor and make sure everything looks alright; however, it's not recommended to | |
| make code fixups via the patch file. It's a better idea to make the change the | |
| normal way using `git rebase -i` or by adding a new commit than by modifying a | |
| patch. | |
| NOTE: Optionally, you can also use the `--rfc` flag to prefix your patch subject | |
| with ``[RFC PATCH]'' instead of ``[PATCH]''. RFC stands for ``request for | |
| comments'' and indicates that while your code isn't quite ready for submission, | |
| you'd like to begin the code review process. This can also be used when your | |
| patch is a proposal, but you aren't sure whether the community wants to solve | |
| the problem with that approach or not - to conduct a sort of design review. You | |
| may also see on the list patches marked ``WIP'' - this means they are incomplete | |
| but want reviewers to look at what they have so far. You can add this flag with | |
| `--subject-prefix=WIP`. | |
| Check and make sure that your patches and cover letter template exist in the | |
| directory you specified - you're nearly ready to send out your review! | |
| [[preparing-cover-letter]] | |
| === Preparing Email | |
| Since you invoked `format-patch` with `--cover-letter`, you've already got a | |
| cover letter template ready. Open it up in your favorite editor. | |
| You should see a number of headers present already. Check that your `From:` | |
| header is correct. Then modify your `Subject:` (see <<cover-letter,above>> for | |
| how to choose good title for your patch series): | |
| ---- | |
| Subject: [PATCH 0/7] Add the 'psuh' command | |
| ---- | |
| Make sure you retain the ``[PATCH 0/X]'' part; that's what indicates to the Git | |
| community that this email is the beginning of a patch series, and many | |
| reviewers filter their email for this type of flag. | |
| You'll need to add some extra parameters when you invoke `git send-email` to add | |
| the cover letter. | |
| Next you'll have to fill out the body of your cover letter. Again, see | |
| <<cover-letter,above>> for what content to include. | |
| The template created by `git format-patch --cover-letter` includes a diffstat. | |
| This gives reviewers a summary of what they're in for when reviewing your topic. | |
| The one generated for `psuh` from the sample implementation looks like this: | |
| ---- | |
| Documentation/git-psuh.txt | 40 +++++++++++++++++++++ | |
| Makefile | 1 + | |
| builtin.h | 1 + | |
| builtin/psuh.c | 73 ++++++++++++++++++++++++++++++++++++++ | |
| git.c | 1 + | |
| t/t9999-psuh-tutorial.sh | 12 +++++++ | |
| 6 files changed, 128 insertions(+) | |
| create mode 100644 Documentation/git-psuh.txt | |
| create mode 100644 builtin/psuh.c | |
| create mode 100755 t/t9999-psuh-tutorial.sh | |
| ---- | |
| Finally, the letter will include the version of Git used to generate the | |
| patches. You can leave that string alone. | |
| [[sending-git-send-email]] | |
| === Sending Email | |
| At this point you should have a directory `psuh/` which is filled with your | |
| patches and a cover letter. Time to mail it out! You can send it like this: | |
| ---- | |
| $ git send-email [email protected] psuh/*.patch | |
| ---- | |
| NOTE: Check `git help send-email` for some other options which you may find | |
| valuable, such as changing the Reply-to address or adding more CC and BCC lines. | |
| NOTE: When you are sending a real patch, it will go to [email protected] - but | |
| please don't send your patchset from the tutorial to the real mailing list! For | |
| now, you can send it to yourself, to make sure you understand how it will look. | |
| After you run the command above, you will be presented with an interactive | |
| prompt for each patch that's about to go out. This gives you one last chance to | |
| edit or quit sending something (but again, don't edit code this way). Once you | |
| press `y` or `a` at these prompts your emails will be sent! Congratulations! | |
| Awesome, now the community will drop everything and review your changes. (Just | |
| kidding - be patient!) | |
| [[v2-git-send-email]] | |
| === Sending v2 | |
| This section will focus on how to send a v2 of your patchset. To learn what | |
| should go into v2, skip ahead to <<reviewing,Responding to Reviews>> for | |
| information on how to handle comments from reviewers. | |
| We'll reuse our `psuh` topic branch for v2. Before we make any changes, we'll | |
| mark the tip of our v1 branch for easy reference: | |
| ---- | |
| $ git checkout psuh | |
| $ git branch psuh-v1 | |
| ---- | |
| Refine your patch series by using `git rebase -i` to adjust commits based upon | |
| reviewer comments. Once the patch series is ready for submission, generate your | |
| patches again, but with some new flags: | |
| ---- | |
| $ git format-patch -v2 --cover-letter -o psuh/ --range-diff master..psuh-v1 master.. | |
| ---- | |
| The `--range-diff master..psuh-v1` parameter tells `format-patch` to include a | |
| range-diff between `psuh-v1` and `psuh` in the cover letter (see | |
| linkgit:git-range-diff[1]). This helps tell reviewers about the differences | |
| between your v1 and v2 patches. | |
| The `-v2` parameter tells `format-patch` to output your patches | |
| as version "2". For instance, you may notice that your v2 patches are | |
| all named like `v2-000n-my-commit-subject.patch`. `-v2` will also format | |
| your patches by prefixing them with "[PATCH v2]" instead of "[PATCH]", | |
| and your range-diff will be prefaced with "Range-diff against v1". | |
| After you run this command, `format-patch` will output the patches to the `psuh/` | |
| directory, alongside the v1 patches. Using a single directory makes it easy to | |
| refer to the old v1 patches while proofreading the v2 patches, but you will need | |
| to be careful to send out only the v2 patches. We will use a pattern like | |
| "psuh/v2-*.patch" (not "psuh/*.patch", which would match v1 and v2 patches). | |
| Edit your cover letter again. Now is a good time to mention what's different | |
| between your last version and now, if it's something significant. You do not | |
| need the exact same body in your second cover letter; focus on explaining to | |
| reviewers the changes you've made that may not be as visible. | |
| You will also need to go and find the Message-Id of your previous cover letter. | |
| You can either note it when you send the first series, from the output of `git | |
| send-email`, or you can look it up on the | |
| https://lore.kernel.org/git[mailing list]. Find your cover letter in the | |
| archives, click on it, then click "permalink" or "raw" to reveal the Message-Id | |
| header. It should match: | |
| ---- | |
| Message-Id: <[email protected]> | |
| ---- | |
| Your Message-Id is `<[email protected]>`. This example will be used | |
| below as well; make sure to replace it with the correct Message-Id for your | |
| **previous cover letter** - that is, if you're sending v2, use the Message-Id | |
| from v1; if you're sending v3, use the Message-Id from v2. | |
| While you're looking at the email, you should also note who is CC'd, as it's | |
| common practice in the mailing list to keep all CCs on a thread. You can add | |
| these CC lines directly to your cover letter with a line like so in the header | |
| (before the Subject line): | |
| ---- | |
| CC: [email protected], Othe R <[email protected]> | |
| ---- | |
| Now send the emails again, paying close attention to which messages you pass in | |
| to the command: | |
| ---- | |
| $ git send-email [email protected] | |
| --in-reply-to="<[email protected]>" | |
| psuh/v2-*.patch | |
| ---- | |
| [[single-patch]] | |
| === Bonus Chapter: One-Patch Changes | |
| In some cases, your very small change may consist of only one patch. When that | |
| happens, you only need to send one email. Your commit message should already be | |
| meaningful and explain at a high level the purpose (what is happening and why) | |
| of your patch, but if you need to supply even more context, you can do so below | |
| the `---` in your patch. Take the example below, which was generated with `git | |
| format-patch` on a single commit, and then edited to add the content between | |
| the `---` and the diffstat. | |
| ---- | |
| From 1345bbb3f7ac74abde040c12e737204689a72723 Mon Sep 17 00:00:00 2001 | |
| From: A U Thor <[email protected]> | |
| Date: Thu, 18 Apr 2019 15:11:02 -0700 | |
| Subject: [PATCH] README: change the grammar | |
| I think it looks better this way. This part of the commit message will | |
| end up in the commit-log. | |
| Signed-off-by: A U Thor <[email protected]> | |
| --- | |
| Let's have a wild discussion about grammar on the mailing list. This | |
| part of my email will never end up in the commit log. Here is where I | |
| can add additional context to the mailing list about my intent, outside | |
| of the context of the commit log. This section was added after `git | |
| format-patch` was run, by editing the patch file in a text editor. | |
| README.md | 2 +- | |
| 1 file changed, 1 insertion(+), 1 deletion(-) | |
| diff --git a/README.md b/README.md | |
| index 88f126184c..38da593a60 100644 | |
| --- a/README.md | |
| +++ b/README.md | |
| @@ -3,7 +3,7 @@ | |
| Git - fast, scalable, distributed revision control system | |
| ========================================================= | |
| -Git is a fast, scalable, distributed revision control system with an | |
| +Git is a fast, scalable, and distributed revision control system with an | |
| unusually rich command set that provides both high-level operations | |
| and full access to internals. | |
| -- | |
| 2.21.0.392.gf8f6787159e-goog | |
| ---- | |
| [[now-what]] | |
| == My Patch Got Emailed - Now What? | |
| [[reviewing]] | |
| === Responding to Reviews | |
| After a few days, you will hopefully receive a reply to your patchset with some | |
| comments. Woohoo! Now you can get back to work. | |
| It's good manners to reply to each comment, notifying the reviewer that you have | |
| made the change suggested, feel the original is better, or that the comment | |
| inspired you to do something a new way which is superior to both the original | |
| and the suggested change. This way reviewers don't need to inspect your v2 to | |
| figure out whether you implemented their comment or not. | |
| Reviewers may ask you about what you wrote in the patchset, either in | |
| the proposed commit log message or in the changes themselves. You | |
| should answer these questions in your response messages, but often the | |
| reason why reviewers asked these questions to understand what you meant | |
| to write is because your patchset needed clarification to be understood. | |
| Do not be satisfied by just answering their questions in your response | |
| and hear them say that they now understand what you wanted to say. | |
| Update your patches to clarify the points reviewers had trouble with, | |
| and prepare your v2; the words you used to explain your v1 to answer | |
| reviewers' questions may be useful thing to use. Your goal is to make | |
| your v2 clear enough so that it becomes unnecessary for you to give the | |
| same explanation to the next person who reads it. | |
| If you are going to push back on a comment, be polite and explain why you feel | |
| your original is better; be prepared that the reviewer may still disagree with | |
| you, and the rest of the community may weigh in on one side or the other. As | |
| with all code reviews, it's important to keep an open mind to doing something a | |
| different way than you originally planned; other reviewers have a different | |
| perspective on the project than you do, and may be thinking of a valid side | |
| effect which had not occurred to you. It is always okay to ask for clarification | |
| if you aren't sure why a change was suggested, or what the reviewer is asking | |
| you to do. | |
| Make sure your email client has a plaintext email mode and it is turned on; the | |
| Git list rejects HTML email. Please also follow the mailing list etiquette | |
| outlined in the | |
| https://kernel.googlesource.com/pub/scm/git/git/+/todo/MaintNotes[Maintainer's | |
| Note], which are similar to etiquette rules in most open source communities | |
| surrounding bottom-posting and inline replies. | |
| When you're making changes to your code, it is cleanest - that is, the resulting | |
| commits are easiest to look at - if you use `git rebase -i` (interactive | |
| rebase). Take a look at this | |
| https://www.oreilly.com/library/view/git-pocket-guide/9781449327507/ch10.html[overview] | |
| from O'Reilly. The general idea is to modify each commit which requires changes; | |
| this way, instead of having a patch A with a mistake, a patch B which was fine | |
| and required no upstream reviews in v1, and a patch C which fixes patch A for | |
| v2, you can just ship a v2 with a correct patch A and correct patch B. This is | |
| changing history, but since it's local history which you haven't shared with | |
| anyone, that is okay for now! (Later, it may not make sense to do this; take a | |
| look at the section below this one for some context.) | |
| [[after-approval]] | |
| === After Review Approval | |
| The Git project has four integration branches: `seen`, `next`, `master`, and | |
| `maint`. Your change will be placed into `seen` fairly early on by the maintainer | |
| while it is still in the review process; from there, when it is ready for wider | |
| testing, it will be merged into `next`. Plenty of early testers use `next` and | |
| may report issues. Eventually, changes in `next` will make it to `master`, | |
| which is typically considered stable. Finally, when a new release is cut, | |
| `maint` is used to base bugfixes onto. As mentioned at the beginning of this | |
| document, you can read `Documents/SubmittingPatches` for some more info about | |
| the use of the various integration branches. | |
| Back to now: your code has been lauded by the upstream reviewers. It is perfect. | |
| It is ready to be accepted. You don't need to do anything else; the maintainer | |
| will merge your topic branch to `next` and life is good. | |
| However, if you discover it isn't so perfect after this point, you may need to | |
| take some special steps depending on where you are in the process. | |
| If the maintainer has announced in the "What's cooking in git.git" email that | |
| your topic is marked for `next` - that is, that they plan to merge it to `next` | |
| but have not yet done so - you should send an email asking the maintainer to | |
| wait a little longer: "I've sent v4 of my series and you marked it for `next`, | |
| but I need to change this and that - please wait for v5 before you merge it." | |
| If the topic has already been merged to `next`, rather than modifying your | |
| patches with `git rebase -i`, you should make further changes incrementally - | |
| that is, with another commit, based on top of the maintainer's topic branch as | |
| detailed in https://github.com/gitster/git. Your work is still in the same topic | |
| but is now incremental, rather than a wholesale rewrite of the topic branch. | |
| The topic branches in the maintainer's GitHub are mirrored in GitGitGadget, so | |
| if you're sending your reviews out that way, you should be sure to open your PR | |
| against the appropriate GitGitGadget/Git branch. | |
| If you're using `git send-email`, you can use it the same way as before, but you | |
| should generate your diffs from `<topic>..<mybranch>` and base your work on | |
| `<topic>` instead of `master`. | |