Re: [PATCH v2] doc: add maintainer book

[Tobin C. Harding]

On Mon, Nov 27, 2017 at 04:57:30PM -0200, Mauro Carvalho Chehab wrote:
> Em Sat, 25 Nov 2017 08:44:19 +1100
> "Tobin C. Harding" <me@xxxxxxxx> escreveu:
> 
> > There is currently very little documentation in the kernel on maintainer
> > level tasks. In particular there are no documents on creating pull
> > requests to submit to Linus.
> > 
> > Quoting Greg Kroah-Hartman on LKML:
> > 
> >     Anyway, this actually came up at the kernel summit / maintainer
> >     meeting a few weeks ago, in that "how do I make a
> >     good pull request to Linus" is something we need to document.
> > 
> >     Here's what I do, and it seems to work well, so maybe we should turn
> >     it into the start of the documentation for how to do it.
> > 
> > (quote references: kernel summit, Europe 2017)
> > 
> > Create a new kernel documentation book 'how to be a maintainer'
> > (suggested by Jonathan Corbet). Add chapters on 'configuring git' and
> > 'creating a pull request'.
> > 
> > Most of the content was written by Linus Torvalds and Greg Kroah-Hartman
> > in discussion on LKML. This is stated at the start of one of the
> > chapters and the original email thread is referenced in
> > 'pull-requests.rst'.
> > 
> > Signed-off-by: Tobin C. Harding <me@xxxxxxxx>
> > ---
> > 
> > v2:
> >  - Change title of book, suggested by Dan Williams.
> > 
> > thanks,
> > Tobin.
> > 
> >  Documentation/index.rst                    |   1 +
> >  Documentation/maintainer/conf.py           |  10 ++
> >  Documentation/maintainer/configure-git.rst |  34 ++++++
> >  Documentation/maintainer/index.rst         |  10 ++
> >  Documentation/maintainer/pull-requests.rst | 178 +++++++++++++++++++++++++++++
> >  5 files changed, 233 insertions(+)
> >  create mode 100644 Documentation/maintainer/conf.py
> >  create mode 100644 Documentation/maintainer/configure-git.rst
> >  create mode 100644 Documentation/maintainer/index.rst
> >  create mode 100644 Documentation/maintainer/pull-requests.rst
> > 
> > diff --git a/Documentation/index.rst b/Documentation/index.rst
> > index cb7f1ba5b3b1..a4fb34dddcf3 100644
> > --- a/Documentation/index.rst
> > +++ b/Documentation/index.rst
> > @@ -52,6 +52,7 @@ merged much easier.
> >     dev-tools/index
> >     doc-guide/index
> >     kernel-hacking/index
> > +   maintainer/index
> >  
> >  Kernel API documentation
> >  ------------------------
> > diff --git a/Documentation/maintainer/conf.py b/Documentation/maintainer/conf.py
> > new file mode 100644
> > index 000000000000..81e9eb7a7884
> > --- /dev/null
> > +++ b/Documentation/maintainer/conf.py
> > @@ -0,0 +1,10 @@
> > +# -*- coding: utf-8; mode: python -*-
> > +
> > +project = 'Linux Kernel Development Documentation'
> > +
> > +tags.add("subproject")
> > +
> > +latex_documents = [
> > +    ('index', 'maintainer.tex', 'Linux Kernel Development Documentation',
> > +     'The kernel development community', 'manual'),
> > +]
> > diff --git a/Documentation/maintainer/configure-git.rst b/Documentation/maintainer/configure-git.rst
> > new file mode 100644
> > index 000000000000..78bbbb0d2c84
> > --- /dev/null
> > +++ b/Documentation/maintainer/configure-git.rst
> > @@ -0,0 +1,34 @@
> > +.. _configuregit:
> > +
> > +Configure Git
> > +=============
> > +
> > +This chapter describes maintainer level git configuration.
> > +
> > +Tagged branches used in :ref:`Documentation/maintainer/pull-requests.rst
> > +<pullrequests>` should be signed with the developers public GPG key. Signed
> > +tags can be created by passing the ``-u`` flag to ``git tag``. However,
> > +since you would *usually* use the same key for the same project, you can
> > +set it once with
> > +::
> > +
> > +	git config user.signingkey "keyname"
> > +
> > +Alternatively, edit your ``.git/config`` or ``~/.gitconfig`` file by hand:
> > +::
> > +
> > +	[user]
> > +		name = Jane Developer
> > +		email = jd@xxxxxxxxxx
> > +		signingkey = jd@xxxxxxxxxx
> > +
> > +You may need to tell ``git`` to use ``gpg2``
> > +::
> > +
> > +	[gpg]
> > +		program = /path/to/gpg2
> > +
> > +You may also like to tell ``gpg`` which ``tty`` to use (add to your shell rc file)
> > +::
> > +
> > +	export GPG_TTY=$(tty)
> > diff --git a/Documentation/maintainer/index.rst b/Documentation/maintainer/index.rst
> > new file mode 100644
> > index 000000000000..fa84ac9cae39
> > --- /dev/null
> > +++ b/Documentation/maintainer/index.rst
> > @@ -0,0 +1,10 @@
> > +==========================
> > +Kernel Maintainer Handbook
> > +==========================
> > +
> > +.. toctree::
> > +   :maxdepth: 2
> > +
> > +   configure-git
> > +   pull-requests
> > +
> > diff --git a/Documentation/maintainer/pull-requests.rst b/Documentation/maintainer/pull-requests.rst
> > new file mode 100644
> > index 000000000000..0ca9f9bfd679
> > --- /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.
> > +Misrepresentation was unintentional but inevitable, please direct abuse to
> > +Tobin C. Harding <me@xxxxxxxx>.
> > +
> > +Original email thread::
> > +
> > +	http://lkml.kernel.org/r/20171114110500.GA21175@xxxxxxxxx
> > +
> > +
> > +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 the developers tree whom you intend to send the pull request to.
> > +
> > +Name your branch in a semi-useful manner, some developers like to use
> > +``for-linus`` for patches that are going to Linus. Greg uses
> > +``char-misc-next`` for his ``char/misc`` driver patches to be merged into
> > +``linux-next``.
> 
> The name of the branch doesn't really matter. At the Linux media tree, I just
> use "master" and "fixes" at the public maintainer's repository:
> 	 https://git.linuxtv.org/media_tree.git/
> 
> I don't care much on pushing branches from the tree at kernel.org, from
> where Linus pick my work:
> 	https://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media.git/
> 
> I still push some branches there from time to time, but just because I
> was lazy enough to remove something from my scripts :-)
> 
> Also, Linus also uses "master" on his public tree ;-)
> 
> Locally, I actually use different names for my work branch (patchwork)
> and I have a "v4l_for_linus" branch from where I generate pull requests
> (with can either have a snapshot of "patchwork" or "fixes" branch,
> depending if the pull request is for a merge window or not). My internal
> names are mapped into the public ones via .git/config, like:
> 
> 	[remote "media_tree"]
> 		push = refs/heads/patchwork:refs/heads/master
> 		...
> 
> In the past, I was using a different naming there, with the Kernel
> version on it, but somewhere in the past I opted to just use "master".
> The rationale is that people usually expect that the main development
> stuff to be on a "master" repository of a random git tree. Also, when
> I need, I create topic branches.
> 
> Anyway, the point is that the branch name actually depends on how
> each maintainer/each subsystem works.
> 
> So, I would remove the above paragraph, as I doubt there is a general
> rule for developer/maintainer's tree branches, and the name there
> doesn't matter much - except on subsystems that use topic branches.
> 
> > +In order to create the pull request you must first tag the branch that you
> > +have just created. Name the tag with something useful that you can
> > +understand if you run across it in a few weeks, and something that will be
> > +"unique".  Continuing Greg's example of the ``char-misc`` tree, for the
> > +patches to be sent to Linus for the 4.15-rc1 merge window (as stated in the
> > +above linked thread) he would name the tag 'char-misc-4.15-rc1'.
> > +::
> > +
> > +	git tag -s char-misc-4.15-rc1 char-misc-next
> > +
> 
> Now, the tag is what really matter, as this is what everybody sees on
> merges, on every clone of upstream's tree.
> 
> In the past, most maintainers were using something like for-linus or for_linus.
> 
> IMHO, not mentioning the subsystem's origin at the tag's name is a bad
> practice,  as it makes harder to identify what tree was merged, specially
> during the merge window, where a lot merges happen on the first days. If 
> you take a look at the recent logs, most maintainers add the name of the
> subsystem at their pull request branch/tag nowadays:
> 
> 	https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/?qt=grep&q=merge+branch
> 
> (still, you would see some using tags/branches named "for_linus",
> "fixes" , etc)
> 
> So, I would change it to something like that:
> 
> "In order to create the pull request you must first tag the branch that you
>  have just created. It is recommended to choose a meaningful tag name,
>  in a way that you and others can understand, even after some time.
>  A good practice is to always include a name that will remind the
>  subsystem of origin and the Kernel version the pull request's aiming.
>  So, for example, a pull  request with miscelaneous 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"
> 
> -
> 
> On a side note, in the case of media, I opt to name the tags with
> a sequencial number that it is unrelated to the rc version:
> 
> 	https://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media.git/refs/tags
> 
> Internally, I use a script that checks the last tag, and increments 1,
> if the upstream Kernel version is the same as the one at the last tag.
> 
> The reason is that it I don't submit pull requests for every single
> -rc kernel, and, sometimes, I end by submitting more than one pull
> request for a single -rc version (usually for -rc1).
> 
> Regards,
> Mauro

Thanks for your suggestions Mauro. Unless any other comments come in on
this I'll work your changes into the next version.

Is there a _correct_ spelling of 'kernel'? Should it be capitalized or
not? You use 'Kernel' but the rest of the document uses 'kernel', I
think we should have a single spelling (at least inside a single
document).

thanks,
Tobin.