0001 .. _pullrequests:
0002
0003 Creating Pull Requests
0004 ======================
0005
0006 This chapter describes how maintainers can create and submit pull requests
0007 to other maintainers. This is useful for transferring changes from one
0008 maintainers tree to another maintainers tree.
0009
0010 This document was written by Tobin C. Harding (who at that time, was not an
0011 experienced maintainer) primarily from comments made by Greg Kroah-Hartman
0012 and Linus Torvalds on LKML. Suggestions and fixes by Jonathan Corbet and
0013 Mauro Carvalho Chehab. Misrepresentation was unintentional but inevitable,
0014 please direct abuse to Tobin C. Harding <me@tobin.cc>.
0015
0016 Original email thread::
0017
0018 https://lore.kernel.org/r/20171114110500.GA21175@kroah.com
0019
0020
0021 Create Branch
0022 -------------
0023
0024 To start with you will need to have all the changes you wish to include in
0025 the pull request on a separate branch. Typically you will base this branch
0026 off of a branch in the developers tree whom you intend to send the pull
0027 request to.
0028
0029 In order to create the pull request you must first tag the branch that you
0030 have just created. It is recommended that you choose a meaningful tag name,
0031 in a way that you and others can understand, even after some time. A good
0032 practice is to include in the name an indicator of the subsystem of origin
0033 and the target kernel version.
0034
0035 Greg offers the following. A pull request with miscellaneous stuff for
0036 drivers/char, to be applied at the Kernel version 4.15-rc1 could be named
0037 as ``char-misc-4.15-rc1``. If such tag would be produced from a branch
0038 named ``char-misc-next``, you would be using the following command::
0039
0040 git tag -s char-misc-4.15-rc1 char-misc-next
0041
0042 that will create a signed tag called ``char-misc-4.15-rc1`` based on the
0043 last commit in the ``char-misc-next`` branch, and sign it with your gpg key
0044 (see :ref:`Documentation/maintainer/configure-git.rst <configuregit>`).
0045
0046 Linus will only accept pull requests based on a signed tag. Other
0047 maintainers may differ.
0048
0049 When you run the above command ``git`` will drop you into an editor and ask
0050 you to describe the tag. In this case, you are describing a pull request,
0051 so outline what is contained here, why it should be merged, and what, if
0052 any, testing has been done. All of this information will end up in the tag
0053 itself, and then in the merge commit that the maintainer makes if/when they
0054 merge the pull request. So write it up well, as it will be in the kernel
0055 tree for forever.
0056
0057 As said by Linus::
0058
0059 Anyway, at least to me, the important part is the *message*. I want
0060 to understand what I'm pulling, and why I should pull it. I also
0061 want to use that message as the message for the merge, so it should
0062 not just make sense to me, but make sense as a historical record
0063 too.
0064
0065 Note that if there is something odd about the pull request, that
0066 should very much be in the explanation. If you're touching files
0067 that you don't maintain, explain _why_. I will see it in the
0068 diffstat anyway, and if you didn't mention it, I'll just be extra
0069 suspicious. And when you send me new stuff after the merge window
0070 (or even bug-fixes, but ones that look scary), explain not just
0071 what they do and why they do it, but explain the _timing_. What
0072 happened that this didn't go through the merge window..
0073
0074 I will take both what you write in the email pull request _and_ in
0075 the signed tag, so depending on your workflow, you can either
0076 describe your work in the signed tag (which will also automatically
0077 make it into the pull request email), or you can make the signed
0078 tag just a placeholder with nothing interesting in it, and describe
0079 the work later when you actually send me the pull request.
0080
0081 And yes, I will edit the message. Partly because I tend to do just
0082 trivial formatting (the whole indentation and quoting etc), but
0083 partly because part of the message may make sense for me at pull
0084 time (describing the conflicts and your personal issues for sending
0085 it right now), but may not make sense in the context of a merge
0086 commit message, so I will try to make it all make sense. I will
0087 also fix any speeling mistaeks and bad grammar I notice,
0088 particularly for non-native speakers (but also for native ones
0089 ;^). But I may miss some, or even add some.
0090
0091 Linus
0092
0093 Greg gives, as an example pull request::
0094
0095 Char/Misc patches for 4.15-rc1
0096
0097 Here is the big char/misc patch set for the 4.15-rc1 merge window.
0098 Contained in here is the normal set of new functions added to all
0099 of these crazy drivers, as well as the following brand new
0100 subsystems:
0101 - time_travel_controller: Finally a set of drivers for the
0102 latest time travel bus architecture that provides i/o to
0103 the CPU before it asked for it, allowing uninterrupted
0104 processing
0105 - relativity_shifters: due to the affect that the
0106 time_travel_controllers have on the overall system, there
0107 was a need for a new set of relativity shifter drivers to
0108 accommodate the newly formed black holes that would
0109 threaten to suck CPUs into them. This subsystem handles
0110 this in a way to successfully neutralize the problems.
0111 There is a Kconfig option to force these to be enabled
0112 when needed, so problems should not occur.
0113
0114 All of these patches have been successfully tested in the latest
0115 linux-next releases, and the original problems that it found have
0116 all been resolved (apologies to anyone living near Canberra for the
0117 lack of the Kconfig options in the earlier versions of the
0118 linux-next tree creations.)
0119
0120 Signed-off-by: Your-name-here <your_email@domain>
0121
0122
0123 The tag message format is just like a git commit id. One line at the top
0124 for a "summary subject" and be sure to sign-off at the bottom.
0125
0126 Now that you have a local signed tag, you need to push it up to where it
0127 can be retrieved::
0128
0129 git push origin char-misc-4.15-rc1
0130
0131
0132 Create Pull Request
0133 -------------------
0134
0135 The last thing to do is create the pull request message. ``git`` handily
0136 will do this for you with the ``git request-pull`` command, but it needs a
0137 bit of help determining what you want to pull, and on what to base the pull
0138 against (to show the correct changes to be pulled and the diffstat). The
0139 following command(s) will generate a pull request::
0140
0141 git request-pull master git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git/ char-misc-4.15-rc1
0142
0143 Quoting Greg::
0144
0145 This is asking git to compare the difference from the
0146 'char-misc-4.15-rc1' tag location, to the head of the 'master'
0147 branch (which in my case points to the last location in Linus's
0148 tree that I diverged from, usually a -rc release) and to use the
0149 git:// protocol to pull from. If you wish to use https://, that
0150 can be used here instead as well (but note that some people behind
0151 firewalls will have problems with https git pulls).
0152
0153 If the char-misc-4.15-rc1 tag is not present in the repo that I am
0154 asking to be pulled from, git will complain saying it is not there,
0155 a handy way to remember to actually push it to a public location.
0156
0157 The output of 'git request-pull' will contain the location of the
0158 git tree and specific tag to pull from, and the full text
0159 description of that tag (which is why you need to provide good
0160 information in that tag). It will also create a diffstat of the
0161 pull request, and a shortlog of the individual commits that the
0162 pull request will provide.
0163
0164 Linus responded that he tends to prefer the ``git://`` protocol. Other
0165 maintainers may have different preferences. Also, note that if you are
0166 creating pull requests without a signed tag then ``https://`` may be a
0167 better choice. Please see the original thread for the full discussion.
0168
0169
0170 Submit Pull Request
0171 -------------------
0172
0173 A pull request is submitted in the same way as an ordinary patch. Send as
0174 inline email to the maintainer and CC LKML and any sub-system specific
0175 lists if required. Pull requests to Linus typically have a subject line
0176 something like::
0177
0178 [GIT PULL] <subsystem> changes for v4.15-rc1
