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