View source for My first pull request to Joomla! on Github

== A Pull Request ?? ==
So what the heck could be a "Pull Request" ? No, I bet it's not what you're thinking right now...

A Pull Request is the Git Jargon meaning "I will send a '''request''' to a project, to '''pull''' in some code changes / additions I have made to their code base"

Got it ? This is how we (including you) are going to contribute source code to the Joomla! code base.

It might look a bit scary at first (at least to me) but in the end it's pretty easy - "similar" to SVN, but a lot better.

Here is how it works:

== Installation ==
The installation depends on the operating system you are using. If you use Linux, you may find the git software in your repository.

For '''example''' [http://opensuse.org OpenSuSE] offers a "pattern" named <code>git</code> that provides the git core (required) as well as a set of tools like [http://gitk.org gitk], an e-mail interface, scripts to import source code from other version control systems like svn and others.

[[File:git-opensuse-install.png]]

For more information about installing git on other operating systems see the GitHub site for [http://help.github.com/linux-set-up-git Linux], [http://help.github.com/mac-set-up-git Mac] and even [http://help.github.com/win-set-up-git Windows].

For this tutorial you will also need [http://eclipse.org/pdt/ Eclipse PDT] with the [http://eclipse.org/egit/ eGit plugin] installed.

== GitHub ==
For this tutorial we have created a GitHub user named '''<code>jlover</code>''' - a dude who loves J :)

He has already [http://help.github.com/fork-a-repo/ forked] the main repository so his repository is at: https://github.com/jlover/joomla-platform

[[File:github-repo.png]]

== Import your clone ==
Mr. JLover uses Linux and his Eclipse workspace is at <code>/home/jlover/workspace</code>

Before eGit 1.0 it was not possible to create or clone repositories right into your workspace. To make things easier we set the default repository folder to our workspace.

[[File:git-eclipse-preferences-1.png]]

Let's start. Go to your workspace, right click inside the PHP explorer and select '''Import...'''.

[[File:git-eclipse-import.png]]

Select '''Git''' &rArr; '''Projects from Git'''

[[File:git-eclipse-import-2.png]]

Click on '''Clone...'''

[[File:git-eclipse-import-3.png]]

=== Source repository ===

In the window that opens up, copy and paste the HTTP URL from your GitHub repository. The remaining fields will be auto filled.

Your may also want to supply your password but this is not required if you limit the write operations to the command line.

[[File:git-eclipse-import-4.png]]

Select the branches you want to clone. The '''master''' branch is the ''point of truth''.

[[File:git-eclipse-import-5.png]]

=== Local destination ===
Now choose where you want to save the files. We will save them in our workspace and modify the default name joomla-platform to '''my-joomla-platform'''.

Please remember this name, as we will use it later when we create our project in the same folder.

[[File:git-eclipse-import-6.png]]

=== Receiving objects... ===
The files are being checked out. Sit back and watch patiently, or go for a cup of coffee ;)

[[File:git-eclipse-import-6-checkout.png]]

Finished. Click '''Next >'''

[[File:git-eclipse-import-7.png]]

== New Project wizard ==

Select '''Use the New Project wizard''' and click '''Finish''' to start it (windows like..)

[[File:git-eclipse-create-project-1.png]]

Select '''PHP''' &rArr; '''PHP Project'''

[[File:git-eclipse-create-project-2.png]]

For the Project name enter the name of the repository you previously cloned. '''my-joola-platform''' in our example.

Observe the message beside the yellow triangle that appears when you finished inserting the Project name, telling you that the specified location already exists.<br />
This is OK and expected.

[[File:git-eclipse-import-8.png]]

Click '''Next >''' and include other libraries if required.

[[File:git-eclipse-import-9.png]]

== Finished ==

After you click Finish, the new project will be created in your workspace.

'''Welcome to the Joomla! platform.'''

[[File:git-eclipse-import-10.png]]

== The upstream repository ==

OK. So far you have a local "clone" of your GitHub repository which is a fork of the main Joomla! repository.

But what if the information in the main Joomla! repository changes ? Remember your fork (and your clone) are completely independent from the main repository. Fortunately git allows you to add multiple repositories to your "working copy" to track changes and merge them with your work.

We are going to add the main repository and call it '''upstream'''. To do this I use the console because I have not figured out yet how to do this in eclipse (@todo?)

<pre>
cd /home/jlover/workspace/my-joomla-platform
git remote add upstream git://github.com/joomla/joomla-platform.git
</pre>

To „update“ your clone with the latest changes from the main repository use

<pre>
git fetch upstream
git merge upstream/master
</pre>

This will '''fetch''' the changes from the upstream repository and '''merge''' the upstream/master branch into your current branch.

== Code away... ==
So what are you waiting for ? Go and fix this bug or implement this cool feature and give it back to the Joomla! project. It's as easy as clicking a button ;)

An example:

Let's create a simple patch file using Eclipse. We're going to add a comment line to a file that is really important to Joomla! and then create a pull request in GitHub to the Joomla! project.

So if the developers decide that your changes are worth being included into the code base, all they have to do is pushing a button and your name gets graved in stone (aka changelog) and the respective ''blame'' will show your name as the author for the lines of code you changed - Is this cute or what ?

== Create a feature branch ==
Git provides a handy feature called [http://book.git-scm.com/3_basic_branching_and_merging.html Branches]. The concept is somewhat similar to SVN but the handling is completely different. This feature is also known as ''cheap branching''.

So if you plan to make more submissions or just to keep you master branch clean, you should create a new branch.

Unfortunately Eclipses branching concept seems to differ a bit from the original. So I use the command line also for branching operations. @todo?

The shortcut for creating and switching to a new branch is <code>checkout -b</code> so we will create a new branch called '''<code>first-test</code>'''

<pre>
cd /home/jlover/workspace/my-joomla-platform
git checkout -b first-test
</pre>

Note that the tree has also changed in eclipse (maybe you need to refresh)

[[File:git-eclipse-tree-details.png]]

OK we can now change whatever we want without "polluting" our original repository. The disk space required to do this is minimal. That's what is meant by ''cheap''...

== Change the code ==
Let's open the file <code>libraries/joomla/application/application.php</code>. and make a test change.

You really should feel a bit important right now doing changes to such an important Joomla! core file - do you ? ;).

Note that after you save the file, a ''dirty'' marker <code>></code> appears. You can change this in the configuration if you prefer the svn icon overlays.

[[File:git-pull-test-change.png]]

That looks good. Now here comes another new concept if you are new to git: To get your changes to you repository on GitHub '''<big>two steps</big>''' are required:

== Step 1 - Commit ==
This step will commit your changes to you '''local''' repository. You can do this from within eclipse selecting the file(s) or folders you want to include in the commit.

Right click you project and select Team &rArr; Commit...

[[File:git-eclipse-commit-1.png]]

In the window that opens enter a meaningfull commit message

[[File:git-eclipse-commit-2.png]]

After you press <code>Commit</code> note that the ''dirty'' marker <code>></code> has disappeared.

You may add as many commits as you like locally before submitting it to the server.

Commit often.

== Step 2 - Push ==
This step will submit your code to the GitHub server(s).

We do this from the command line @todo?

<pre>git push origin first-test</pre>
This will push your changes to '''<code>origin</code>''' (your (jlovers) repository on GitHub) and create a new branch named '''<code>first-test</code>'''

Done. Your changes are on the internet. Let's check out the GitHub site

[[File:git-pull-feed-1.png]]

Looks good.

A nice feature in eclipse is the history view

[[File:git-eclipse-history-view.png]]

== The Pull Request ==
At this point we are finally ready to do our pull request. Let's go to our repository, be sure that you are on the correct branch (you may change this later), and find the '''Pull Request''' button.

Push it softly, nothing will really happen yet ;)

[[File:github-pull-request-1.png]]

On the next screen you should enter a meaningful message to the developers.

Pay attention to the text white on black that shows '''from''' and '''to''' which repository:branch you are going to send your pull request. By pushing the button '''Change Commits''' you may modify those values.

[[File:github-pull-request-2.png]]

Here you can preview the changes you are proposing.

[[File:github-pull-request-3.png]]

== Push the Button ==
Ok, we are ready to '''Push the Button''' [[File:Button_send_pull_request.png]]

Thank you for your attention and in advance for your contribution(s) to the Joomla! project.

== Play ==
The Joomla! CMS actually is also moving to GitHub. To get you up and running (yes You who are not familiar with this git and GitHub stuff yet), a ''playground branch'' has been created to...imagine: '''Play'''.

https://github.com/joomla/joomla-cms/tree/playground

So go on and '''play'''.

Thanks for your attention.