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diff --git a/Documentation/maintainer/pull-requests.rst b/Documentation/maintainer/pull-requests.rst new file mode 100644 index 000000000..e072de60c --- /dev/null +++ b/Documentation/maintainer/pull-requests.rst @@ -0,0 +1,178 @@ +.. _pullrequests: + +Creating Pull Requests +====================== + +This chapter describes how maintainers can create and submit pull requests +to other maintainers. This is useful for transferring changes from one +maintainers tree to another maintainers tree. + +This document was written by Tobin C. Harding (who at that time, was not an +experienced maintainer) primarily from comments made by Greg Kroah-Hartman +and Linus Torvalds on LKML. Suggestions and fixes by Jonathan Corbet and +Mauro Carvalho Chehab. Misrepresentation was unintentional but inevitable, +please direct abuse to Tobin C. Harding <me@tobin.cc>. + +Original email thread:: + + https://lore.kernel.org/r/20171114110500.GA21175@kroah.com + + +Create Branch +------------- + +To start with you will need to have all the changes you wish to include in +the pull request on a separate branch. Typically you will base this branch +off of a branch in the developers tree whom you intend to send the pull +request to. + +In order to create the pull request you must first tag the branch that you +have just created. It is recommended that you choose a meaningful tag name, +in a way that you and others can understand, even after some time. A good +practice is to include in the name an indicator of the subsystem of origin +and the target kernel version. + +Greg offers the following. A pull request with miscellaneous stuff for +drivers/char, to be applied at the Kernel version 4.15-rc1 could be named +as ``char-misc-4.15-rc1``. If such tag would be produced from a branch +named ``char-misc-next``, you would be using the following command:: + + git tag -s char-misc-4.15-rc1 char-misc-next + +that will create a signed tag called ``char-misc-4.15-rc1`` based on the +last commit in the ``char-misc-next`` branch, and sign it with your gpg key +(see :ref:`Documentation/maintainer/configure-git.rst <configuregit>`). + +Linus will only accept pull requests based on a signed tag. Other +maintainers may differ. + +When you run the above command ``git`` will drop you into an editor and ask +you to describe the tag. In this case, you are describing a pull request, +so outline what is contained here, why it should be merged, and what, if +any, testing has been done. All of this information will end up in the tag +itself, and then in the merge commit that the maintainer makes if/when they +merge the pull request. So write it up well, as it will be in the kernel +tree for forever. + +As said by Linus:: + + Anyway, at least to me, the important part is the *message*. I want + to understand what I'm pulling, and why I should pull it. I also + want to use that message as the message for the merge, so it should + not just make sense to me, but make sense as a historical record + too. + + Note that if there is something odd about the pull request, that + should very much be in the explanation. If you're touching files + that you don't maintain, explain _why_. I will see it in the + diffstat anyway, and if you didn't mention it, I'll just be extra + suspicious. And when you send me new stuff after the merge window + (or even bug-fixes, but ones that look scary), explain not just + what they do and why they do it, but explain the _timing_. What + happened that this didn't go through the merge window.. + + I will take both what you write in the email pull request _and_ in + the signed tag, so depending on your workflow, you can either + describe your work in the signed tag (which will also automatically + make it into the pull request email), or you can make the signed + tag just a placeholder with nothing interesting in it, and describe + the work later when you actually send me the pull request. + + And yes, I will edit the message. Partly because I tend to do just + trivial formatting (the whole indentation and quoting etc), but + partly because part of the message may make sense for me at pull + time (describing the conflicts and your personal issues for sending + it right now), but may not make sense in the context of a merge + commit message, so I will try to make it all make sense. I will + also fix any speeling mistaeks and bad grammar I notice, + particularly for non-native speakers (but also for native ones + ;^). But I may miss some, or even add some. + + Linus + +Greg gives, as an example pull request:: + + Char/Misc patches for 4.15-rc1 + + Here is the big char/misc patch set for the 4.15-rc1 merge window. + Contained in here is the normal set of new functions added to all + of these crazy drivers, as well as the following brand new + subsystems: + - time_travel_controller: Finally a set of drivers for the + latest time travel bus architecture that provides i/o to + the CPU before it asked for it, allowing uninterrupted + processing + - relativity_shifters: due to the affect that the + time_travel_controllers have on the overall system, there + was a need for a new set of relativity shifter drivers to + accommodate the newly formed black holes that would + threaten to suck CPUs into them. This subsystem handles + this in a way to successfully neutralize the problems. + There is a Kconfig option to force these to be enabled + when needed, so problems should not occur. + + All of these patches have been successfully tested in the latest + linux-next releases, and the original problems that it found have + all been resolved (apologies to anyone living near Canberra for the + lack of the Kconfig options in the earlier versions of the + linux-next tree creations.) + + Signed-off-by: Your-name-here <your_email@domain> + + +The tag message format is just like a git commit id. One line at the top +for a "summary subject" and be sure to sign-off at the bottom. + +Now that you have a local signed tag, you need to push it up to where it +can be retrieved:: + + git push origin char-misc-4.15-rc1 + + +Create Pull Request +------------------- + +The last thing to do is create the pull request message. ``git`` handily +will do this for you with the ``git request-pull`` command, but it needs a +bit of help determining what you want to pull, and on what to base the pull +against (to show the correct changes to be pulled and the diffstat). The +following command(s) will generate a pull request:: + + git request-pull master git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git/ char-misc-4.15-rc1 + +Quoting Greg:: + + This is asking git to compare the difference from the + 'char-misc-4.15-rc1' tag location, to the head of the 'master' + branch (which in my case points to the last location in Linus's + tree that I diverged from, usually a -rc release) and to use the + git:// protocol to pull from. If you wish to use https://, that + can be used here instead as well (but note that some people behind + firewalls will have problems with https git pulls). + + If the char-misc-4.15-rc1 tag is not present in the repo that I am + asking to be pulled from, git will complain saying it is not there, + a handy way to remember to actually push it to a public location. + + The output of 'git request-pull' will contain the location of the + git tree and specific tag to pull from, and the full text + description of that tag (which is why you need to provide good + information in that tag). It will also create a diffstat of the + pull request, and a shortlog of the individual commits that the + pull request will provide. + +Linus responded that he tends to prefer the ``git://`` protocol. Other +maintainers may have different preferences. Also, note that if you are +creating pull requests without a signed tag then ``https://`` may be a +better choice. Please see the original thread for the full discussion. + + +Submit Pull Request +------------------- + +A pull request is submitted in the same way as an ordinary patch. Send as +inline email to the maintainer and CC LKML and any sub-system specific +lists if required. Pull requests to Linus typically have a subject line +something like:: + + [GIT PULL] <subsystem> changes for v4.15-rc1 |