wmaker: remove useless null pointer check (Coverity #109612)

[wmaker-crm.git] / The-perfect-Window-Maker-patch.txt

____________
Introduction
------------

These notes are meant to help you in the process of making and submitting
patches to the git repository of wmaker-crm.

It assumes you have 'git' correctly installed and you have set the most
basic configuration options via 'git config'. See the end of this file
for an example .gitconfig.

To clone the wmaker-crm repository you can do:

git clone git://repo.or.cz/wmaker-crm.git

You should note that the development occur in the #next branch, and
patches are backported to #master when considered ok. So, you probably
want to switch to #next branch, if not already done:

git checkout next

____________________
Testing your changes
--------------------

If you want to raise the quality of your contribution, you are strongly
encouraged to use at least this configure option:

./configure --enable-debug

This does not only enable debugging information, which you may need when
testing your work, it also enables a number of extra compiler warning
which help keeping safer code.

You will probably want also to run this in the end, because it does some
checks on the source tree:

make check

__________________________
Producing a patch with git
--------------------------

You have the wmaker source and you want to write a patch in order to fix
a bug or improve something. A possible work-flow is the following:

# Optional: Create a new branch (to be safe in case you screw up)
git checkout -b fixbug

Now you fix the bug...

# Check what you did, review etc
git diff

# if it looks good, commit your changes
git commit -a

Git will open the editor set in your .gitconfig and you'll have to write a
commit message. Writing a good message is as important as the source code
modifications you've just made! See "Writing the commit log" for advice.

# Prepare the patch to submit to the mailing-list.
# (use HEAD~2 if you want patches for the last 2 commits etc)
git format-patch HEAD~1

# If you have created your own branch, and want all your commits created
# after the #next branch, you can use:
git format-patch next


In order to ensure consistency in the code, there's an extra step to
check the patchs. You should run this script (inherited from the Linux
kernel) on the patch files generated and fix your commits for what it
reports:

./checkpatch.pl 00*

______________________
Writing the commit log
----------------------

You had a motivation to write your patch, you studied the sources and you
found a way to do what you wanted to do. This whole process takes time and
other people will not want to invest that time to rediscover what you've
already found.

So the main reason for the commit message is to explain to other people what
you did, _why_ and _how_. And you must assume that the person you must explain
these things to will not be as familiar with the code you just modified as you
are right after writing the patch -- and that includes yourself in a year or
so. Be verbose in all the steps below.

The good commit log will start with the reason for writing the patch.

For example, if you use wmaker in some way and you expect that X happens but
you get Y, you should say that very clearly. Sometimes that's enough for other
more experienced people to know how to solve your issue. They will be able to
judge your patch better if they know what you wanted to do -- sometimes there
can be a better way to fix it.

Then you should explain why the wmaker source leads to Y and not to X.

Technical stuff can be expected at this point, e.g. "upon doing xyz in function
foobar(), wmaker sets the variable foo to 'y' instead of setting it to 'x', and
that will lead to blabla happening in function foobar_squared()...".

And finally you explain how you fixed it.

"You have to set foo to 'x', because then when the function foobar_squared() is
called it will do X instead of Y because..."

At this point other people will have a clear understanding of what you did with
minimal effort. And that leads to better patch reviews.

Furthermore, the above reasons should also tell you that you must not do
more than one thing in the same patch. Again:

       "Each patch must do one thing and one thing only."

If your patch does too much of unrelated stuff, it makes reviewing a nightmare
and long-term maintenance much worse (think about a patch which introduces a
regression in the middle of many other nice improvements, and now you have to
get rid of the regression without removing the improvements -- 'git revert'
will not help you here).

If you find yourself having troubles to write what you did in the commit
message, perhaps you did too much. In this case you should split your patch
into smaller unrelated pieces and produce a patch series. Unfortunately it's
more work for you, but it's much better for wmaker.

_____________________________________
Sending the patch to the mailing list
-------------------------------------

Send your patches to:

wmaker-dev@lists.windowmaker.org

Please do not send patches to any individual developer unless you have a very
good reason to avoid more people being able to comment (and improve) on your
patches.

The HIGHLY RECOMMENDED way to send a patch is to actually let Git do it for
you, otherwise you may face the problems below. Doing this is really easy:

# Tell git once how to send mails:
#   (of course, replace smtp.example.com with your ISP's)
git config --global sendemail.smtpserver "smtp.example.com"
git config --global sendemail.validate   true
git config sendemail.to "Window Maker Devel <wmaker-dev@lists.windowmaker.org>"

# If you're sending more than 1 patch, you may be interested in having an
# introduction mail for the batch:
git format-patch  --cover-letter  next
vi/emacs/nedit/whatever 0000-cover-letter.patch

# When you're satisfied, ask Git to mail all the patches:
git send-email 00*


If you do not want or cannot let Git send them for you, please note that
sending the patch _properly_ is not as trivial as you may think. Some mail
clients convert TABs to spaces or word wrap long lines automatically, which
will result in your patch being rejected as it will not apply with 'git apply'.

You could send the patch as an attachement to the mail, but this generally
makes it a bit harder to review, and a lot harder to comment on; that's why
the preferred method is inlined patches (like Git does).

Ideally your patch should contain a very good commit message that explains
why you wrote the patch in the first place (see "Writing the commit log").
In this case you can simply send the file(s) created in the 'git format-patch'
step above as the sole content of your email to the mailing list. All your
reasons and explanations will be in the commit log, and your email will look
like:

**********************************
From: someone@someplace
Subject: [PATCH] Fix something

The commit message.

The diff itself.

**********************************

Read the file email-clients.txt in the topdir of the wmaker-crm repository
to be advised on how to tweak your email client to avoid common pitfalls.

___________________
Example .gitconfig
-------------------

[user]
        name = Erwin Schrodinger
        email = schrodinger@gmail.com
[core]
        editor = xjed
[status]
        showUntrackedFiles = no
[color]
        branch = auto
        status = auto
        diff = auto
        ui = auto
[apply]
        whitespace = fix