diff --git a/MyFirstContribution.html b/MyFirstContribution.html deleted file mode 100644 index d576d1058..000000000 --- a/MyFirstContribution.html +++ /dev/null @@ -1,1968 +0,0 @@ - - - - - - -My First Contribution to the Git Project - - - - - -
-
-

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

-

This tutorial assumes you’re already fairly familiar with using Git to manage -source code. The Git workflow steps will largely remain unexplained.

-
-
- -

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

-

If you get stuck, you can seek help in the following places.

-
-

git@vger.kernel.org

-

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 majordomo@vger.kernel.org with "subscribe git" -in the body. The archive of this mailing list is -available to view in a browser.

-
-
-

git-mentoring@googlegroups.com

-

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.

-
-
-

#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 -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

-
-
-

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
-
-
-
-

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 to Solve

-

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.)

-
-
-

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!

-
-
- - - -
-
Note
-		A reference implementation can be found at -https://github.com/nasamuffin/git/tree/psuh.
-
-
-

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 <author@example.com>
-
-

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

-

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"
-
-
-
-

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:

-
-
-
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.

-
-
-

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

-
-

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 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.

-
-
-

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.

-
-
-

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.

-
-
-
-
-

Getting Ready to Share

-
-

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 patches from -pull requests, and the patches emailed for review need to be formatted a -specific way. 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.

-
-
-
-

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.

-
-

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 GitHub mirror and look for the Fork -button. Place your fork wherever you deem appropriate and create it.

-
-
-

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 git@github.com: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.

-
-
-

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 it’s used by GitGitGadget as the cover -letter for your change. When you’re happy, submit your pull request.

-
-
-

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 -(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 -#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.

-
-
-

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.

-
-
-

Updating With Comments

-

Skip ahead to 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.

-
-
-
-
-

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.

-
-

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.

-
-
-

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
-
-
    -
  1. -

    -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. -

    -
    2. -
  2. -

    -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. -

    -
    3. -
  3. -

    -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. -

    -
    4. -
  4. -

    -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. -

    -
    5. -
-

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 Email

-

In addition to an email per patch, the Git community also expects your patches -to come with a cover letter, typically with a subject line [PATCH 0/x] (where -x is the number of patches you’re sending). Since you invoked format-patch -with --cover-letter, you’ve already got a 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: to something which succinctly -covers the purpose of your entire topic branch, for example:

-
-
-
Subject: [PATCH 0/7] adding 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 review, 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. 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 diff. Be sure to explain anything your diff doesn’t make clear -on its own.

-

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.
-
-

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 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 --to=target@example.com 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 git@vger.kernel.org - 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!)

-
-
-

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 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 -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".

-

Afer 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 -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: <foo.12345.author@example.com>
-
-

Your Message-Id is <foo.12345.author@example.com>. 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: author@example.com, Othe R <other@example.com>
-
-

Now send the emails again, paying close attention to which messages you pass in -to the command:

-
-
-
$ git send-email --to=target@example.com
-                 --in-reply-to="<foo.12345.author@example.com>"
-                 psuh/v2-*.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 <author@example.com>
-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 <author@example.com>
----
-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
-
-
-
-
-
-

My Patch Got Emailed - Now What?

-
-
-

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 -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 -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 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.

-
-
-
-
-
- - -