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1Creating Pull Requests
2======================
3
4This chapter describes how maintainers can create and submit pull requests
5to other maintainers. This is useful for transferring changes from one
6maintainers tree to another maintainers tree.
7
8This document was written by Tobin C. Harding (who at that time, was not an
9experienced maintainer) primarily from comments made by Greg Kroah-Hartman
10and Linus Torvalds on LKML. Suggestions and fixes by Jonathan Corbet and
11Mauro Carvalho Chehab. Misrepresentation was unintentional but inevitable,
12please direct abuse to Tobin C. Harding <me@tobin.cc>.
13
14Original email thread::
15
16 https://lore.kernel.org/r/20171114110500.GA21175@kroah.com
17
18
19Create Branch
20-------------
21
22To start with you will need to have all the changes you wish to include in
23the pull request on a separate branch. Typically you will base this branch
24off of a branch in the developers tree whom you intend to send the pull
25request to.
26
27In order to create the pull request you must first tag the branch that you
28have just created. It is recommended that you choose a meaningful tag name,
29in a way that you and others can understand, even after some time. A good
30practice is to include in the name an indicator of the subsystem of origin
31and the target kernel version.
32
33Greg offers the following. A pull request with miscellaneous stuff for
34drivers/char, to be applied at the Kernel version 4.15-rc1 could be named
35as ``char-misc-4.15-rc1``. If such tag would be produced from a branch
36named ``char-misc-next``, you would be using the following command::
37
38 git tag -s char-misc-4.15-rc1 char-misc-next
39
40that will create a signed tag called ``char-misc-4.15-rc1`` based on the
41last commit in the ``char-misc-next`` branch, and sign it with your gpg key
42(see Documentation/maintainer/configure-git.rst).
43
44Linus will only accept pull requests based on a signed tag. Other
45maintainers may differ.
46
47When you run the above command ``git`` will drop you into an editor and ask
48you to describe the tag. In this case, you are describing a pull request,
49so outline what is contained here, why it should be merged, and what, if
50any, testing has been done. All of this information will end up in the tag
51itself, and then in the merge commit that the maintainer makes if/when they
52merge the pull request. So write it up well, as it will be in the kernel
53tree forever.
54
55As said by Linus::
56
57 Anyway, at least to me, the important part is the *message*. I want
58 to understand what I'm pulling, and why I should pull it. I also
59 want to use that message as the message for the merge, so it should
60 not just make sense to me, but make sense as a historical record
61 too.
62
63 Note that if there is something odd about the pull request, that
64 should very much be in the explanation. If you're touching files
65 that you don't maintain, explain _why_. I will see it in the
66 diffstat anyway, and if you didn't mention it, I'll just be extra
67 suspicious. And when you send me new stuff after the merge window
68 (or even bug-fixes, but ones that look scary), explain not just
69 what they do and why they do it, but explain the _timing_. What
70 happened that this didn't go through the merge window..
71
72 I will take both what you write in the email pull request _and_ in
73 the signed tag, so depending on your workflow, you can either
74 describe your work in the signed tag (which will also automatically
75 make it into the pull request email), or you can make the signed
76 tag just a placeholder with nothing interesting in it, and describe
77 the work later when you actually send me the pull request.
78
79 And yes, I will edit the message. Partly because I tend to do just
80 trivial formatting (the whole indentation and quoting etc), but
81 partly because part of the message may make sense for me at pull
82 time (describing the conflicts and your personal issues for sending
83 it right now), but may not make sense in the context of a merge
84 commit message, so I will try to make it all make sense. I will
85 also fix any speeling mistaeks and bad grammar I notice,
86 particularly for non-native speakers (but also for native ones
87 ;^). But I may miss some, or even add some.
88
89 Linus
90
91Greg gives, as an example pull request::
92
93 Char/Misc patches for 4.15-rc1
94
95 Here is the big char/misc patch set for the 4.15-rc1 merge window.
96 Contained in here is the normal set of new functions added to all
97 of these crazy drivers, as well as the following brand new
98 subsystems:
99 - time_travel_controller: Finally a set of drivers for the
100 latest time travel bus architecture that provides i/o to
101 the CPU before it asked for it, allowing uninterrupted
102 processing
103 - relativity_shifters: due to the affect that the
104 time_travel_controllers have on the overall system, there
105 was a need for a new set of relativity shifter drivers to
106 accommodate the newly formed black holes that would
107 threaten to suck CPUs into them. This subsystem handles
108 this in a way to successfully neutralize the problems.
109 There is a Kconfig option to force these to be enabled
110 when needed, so problems should not occur.
111
112 All of these patches have been successfully tested in the latest
113 linux-next releases, and the original problems that it found have
114 all been resolved (apologies to anyone living near Canberra for the
115 lack of the Kconfig options in the earlier versions of the
116 linux-next tree creations.)
117
118 Signed-off-by: Your-name-here <your_email@domain>
119
120
121The tag message format is just like a git commit id. One line at the top
122for a "summary subject" and be sure to sign-off at the bottom.
123
124Now that you have a local signed tag, you need to push it up to where it
125can be retrieved::
126
127 git push origin char-misc-4.15-rc1
128
129
130Create Pull Request
131-------------------
132
133The last thing to do is create the pull request message. ``git`` handily
134will do this for you with the ``git request-pull`` command, but it needs a
135bit of help determining what you want to pull, and on what to base the pull
136against (to show the correct changes to be pulled and the diffstat). The
137following command(s) will generate a pull request::
138
139 git request-pull master git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git/ char-misc-4.15-rc1
140
141Quoting Greg::
142
143 This is asking git to compare the difference from the
144 'char-misc-4.15-rc1' tag location, to the head of the 'master'
145 branch (which in my case points to the last location in Linus's
146 tree that I diverged from, usually a -rc release) and to use the
147 git:// protocol to pull from. If you wish to use https://, that
148 can be used here instead as well (but note that some people behind
149 firewalls will have problems with https git pulls).
150
151 If the char-misc-4.15-rc1 tag is not present in the repo that I am
152 asking to be pulled from, git will complain saying it is not there,
153 a handy way to remember to actually push it to a public location.
154
155 The output of 'git request-pull' will contain the location of the
156 git tree and specific tag to pull from, and the full text
157 description of that tag (which is why you need to provide good
158 information in that tag). It will also create a diffstat of the
159 pull request, and a shortlog of the individual commits that the
160 pull request will provide.
161
162Linus responded that he tends to prefer the ``git://`` protocol. Other
163maintainers may have different preferences. Also, note that if you are
164creating pull requests without a signed tag then ``https://`` may be a
165better choice. Please see the original thread for the full discussion.
166
167
168Submit Pull Request
169-------------------
170
171A pull request is submitted in the same way as an ordinary patch. Send as
172inline email to the maintainer and CC LKML and any sub-system specific
173lists if required. Pull requests to Linus typically have a subject line
174something like::
175
176 [GIT PULL] <subsystem> changes for v4.15-rc1
1.. _pullrequests:
2
3Creating Pull Requests
4======================
5
6This chapter describes how maintainers can create and submit pull requests
7to other maintainers. This is useful for transferring changes from one
8maintainers tree to another maintainers tree.
9
10This document was written by Tobin C. Harding (who at that time, was not an
11experienced maintainer) primarily from comments made by Greg Kroah-Hartman
12and Linus Torvalds on LKML. Suggestions and fixes by Jonathan Corbet and
13Mauro Carvalho Chehab. Misrepresentation was unintentional but inevitable,
14please direct abuse to Tobin C. Harding <me@tobin.cc>.
15
16Original email thread::
17
18 http://lkml.kernel.org/r/20171114110500.GA21175@kroah.com
19
20
21Create Branch
22-------------
23
24To start with you will need to have all the changes you wish to include in
25the pull request on a separate branch. Typically you will base this branch
26off of a branch in the developers tree whom you intend to send the pull
27request to.
28
29In order to create the pull request you must first tag the branch that you
30have just created. It is recommended that you choose a meaningful tag name,
31in a way that you and others can understand, even after some time. A good
32practice is to include in the name an indicator of the subsystem of origin
33and the target kernel version.
34
35Greg offers the following. A pull request with miscellaneous stuff for
36drivers/char, to be applied at the Kernel version 4.15-rc1 could be named
37as ``char-misc-4.15-rc1``. If such tag would be produced from a branch
38named ``char-misc-next``, you would be using the following command::
39
40 git tag -s char-misc-4.15-rc1 char-misc-next
41
42that will create a signed tag called ``char-misc-4.15-rc1`` based on the
43last commit in the ``char-misc-next`` branch, and sign it with your gpg key
44(see :ref:`Documentation/maintainer/configure-git.rst <configuregit>`).
45
46Linus will only accept pull requests based on a signed tag. Other
47maintainers may differ.
48
49When you run the above command ``git`` will drop you into an editor and ask
50you to describe the tag. In this case, you are describing a pull request,
51so outline what is contained here, why it should be merged, and what, if
52any, testing has been done. All of this information will end up in the tag
53itself, and then in the merge commit that the maintainer makes if/when they
54merge the pull request. So write it up well, as it will be in the kernel
55tree for forever.
56
57As said by Linus::
58
59 Anyway, at least to me, the important part is the *message*. I want
60 to understand what I'm pulling, and why I should pull it. I also
61 want to use that message as the message for the merge, so it should
62 not just make sense to me, but make sense as a historical record
63 too.
64
65 Note that if there is something odd about the pull request, that
66 should very much be in the explanation. If you're touching files
67 that you don't maintain, explain _why_. I will see it in the
68 diffstat anyway, and if you didn't mention it, I'll just be extra
69 suspicious. And when you send me new stuff after the merge window
70 (or even bug-fixes, but ones that look scary), explain not just
71 what they do and why they do it, but explain the _timing_. What
72 happened that this didn't go through the merge window..
73
74 I will take both what you write in the email pull request _and_ in
75 the signed tag, so depending on your workflow, you can either
76 describe your work in the signed tag (which will also automatically
77 make it into the pull request email), or you can make the signed
78 tag just a placeholder with nothing interesting in it, and describe
79 the work later when you actually send me the pull request.
80
81 And yes, I will edit the message. Partly because I tend to do just
82 trivial formatting (the whole indentation and quoting etc), but
83 partly because part of the message may make sense for me at pull
84 time (describing the conflicts and your personal issues for sending
85 it right now), but may not make sense in the context of a merge
86 commit message, so I will try to make it all make sense. I will
87 also fix any speeling mistaeks and bad grammar I notice,
88 particularly for non-native speakers (but also for native ones
89 ;^). But I may miss some, or even add some.
90
91 Linus
92
93Greg gives, as an example pull request::
94
95 Char/Misc patches for 4.15-rc1
96
97 Here is the big char/misc patch set for the 4.15-rc1 merge window.
98 Contained in here is the normal set of new functions added to all
99 of these crazy drivers, as well as the following brand new
100 subsystems:
101 - time_travel_controller: Finally a set of drivers for the
102 latest time travel bus architecture that provides i/o to
103 the CPU before it asked for it, allowing uninterrupted
104 processing
105 - relativity_shifters: due to the affect that the
106 time_travel_controllers have on the overall system, there
107 was a need for a new set of relativity shifter drivers to
108 accommodate the newly formed black holes that would
109 threaten to suck CPUs into them. This subsystem handles
110 this in a way to successfully neutralize the problems.
111 There is a Kconfig option to force these to be enabled
112 when needed, so problems should not occur.
113
114 All of these patches have been successfully tested in the latest
115 linux-next releases, and the original problems that it found have
116 all been resolved (apologies to anyone living near Canberra for the
117 lack of the Kconfig options in the earlier versions of the
118 linux-next tree creations.)
119
120 Signed-off-by: Your-name-here <your_email@domain>
121
122
123The tag message format is just like a git commit id. One line at the top
124for a "summary subject" and be sure to sign-off at the bottom.
125
126Now that you have a local signed tag, you need to push it up to where it
127can be retrieved::
128
129 git push origin char-misc-4.15-rc1
130
131
132Create Pull Request
133-------------------
134
135The last thing to do is create the pull request message. ``git`` handily
136will do this for you with the ``git request-pull`` command, but it needs a
137bit of help determining what you want to pull, and on what to base the pull
138against (to show the correct changes to be pulled and the diffstat). The
139following command(s) will generate a pull request::
140
141 git request-pull master git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git/ char-misc-4.15-rc1
142
143Quoting Greg::
144
145 This is asking git to compare the difference from the
146 'char-misc-4.15-rc1' tag location, to the head of the 'master'
147 branch (which in my case points to the last location in Linus's
148 tree that I diverged from, usually a -rc release) and to use the
149 git:// protocol to pull from. If you wish to use https://, that
150 can be used here instead as well (but note that some people behind
151 firewalls will have problems with https git pulls).
152
153 If the char-misc-4.15-rc1 tag is not present in the repo that I am
154 asking to be pulled from, git will complain saying it is not there,
155 a handy way to remember to actually push it to a public location.
156
157 The output of 'git request-pull' will contain the location of the
158 git tree and specific tag to pull from, and the full text
159 description of that tag (which is why you need to provide good
160 information in that tag). It will also create a diffstat of the
161 pull request, and a shortlog of the individual commits that the
162 pull request will provide.
163
164Linus responded that he tends to prefer the ``git://`` protocol. Other
165maintainers may have different preferences. Also, note that if you are
166creating pull requests without a signed tag then ``https://`` may be a
167better choice. Please see the original thread for the full discussion.
168
169
170Submit Pull Request
171-------------------
172
173A pull request is submitted in the same way as an ordinary patch. Send as
174inline email to the maintainer and CC LKML and any sub-system specific
175lists if required. Pull requests to Linus typically have a subject line
176something like::
177
178 [GIT PULL] <subsystem> changes for v4.15-rc1