== Develop a Feature/Bug Fix

In this exercise you will learn how to develop a new feature using EGit.
We recommend to use a new local branch for each new change (feature or
bug fix).

=== Create a local feature branch
The development of a new feature (or bug-fix) should normally only depend on
the submitted state of the project (and not depend on pending changes that
might or might not pass the code review). This is why every new feature or
bug-fix should be developed in isolation on its own branch which is usually
created based on the latest state of the master branch available on the server
(this is the remote tracking branch 'origin/master' in your local clone).

Go to the 'Git Repositories View'

Select the remote tracking branch 'origin/master' under 'repository > Branches
> Remote Tracking' and click 'Create Branch...'

image:create-branch.png[Create branch]

In the new branch dialog:

* enter a name for the local feature branch into the 'Branch Name' field (this
  is just a local name that is not exposed to anybody else)
* set the 'Pull Strategy' to 'Rebase'
* keep 'Checkout new branch' selected
* confirm the dialog by clicking on 'Finish'

image:create-branch-dialog.png[Create new branch]

This creates and checks out the new branch:

image:new-branch-checked-out.png[New branch checked out]

=== Develop the feature
Simply start editing the source code and implement the feature. The example
project implements a simple calculator, you may want to add an operation.

Create a new class 'Divide.java' in the package
'org.eclipse.example.calc.internal.operations' that

* implements the interface 'org.eclipse.example.calc.BinaryOperation' and
* extends the class 'org.eclipse.example.calc.internal.operations.AbstractOperation'

image:divide-class.png[Divide Class]

To register the new operation add a corresponding line to
the 'Calculator.setupDefaultOperations'.

image:register-divide.png[Register Divide]

You may also decide to do something else like polish the SWT or Swing UI.

=== Test your feature
Run the unit tests. To keep the tutorial setup simple there are only unit tests
for the logic but no UI tests.

image:run-tests.png[Run Tests]

=== Commit your changes locally
Now you want to create a new version of the local repository in your current
feature branch containing your changes. This is called 'commit'.

There are two ways to perform a commit: with the 'Commit Dialog' or from the
'Staging View'. In this exercise we will use the commit dialog.  Select your
project in the 'Package Explorer' and select 'Team > Commit' or click 'Commit'
in the 'Git Toolbar'

image:team-commit.png[Commit]


In the 'Commit Changes' dialog:

* Enter a commit message (explaining why the change was done is more important
  than what was done since this can anyway be seen from the file diffs)
* Verify that 'Author' and 'Committer' contain both your full name and your
  correct e-mail address in the following format: 'John Doe <john.doe@example.org>'

NOTE: If author and committer are not preset correctly you need to change the
Git configuration parameters 'user.name' and/or 'user.email'. In this case
cancel the dialog and open 'Preferences > Team > Git > Configuration > User
Settings' and correct the values for 'user.name' and 'user.email'.

* Select all files that you want to commit
* Click 'Commit'. As result your changes are committed in your *local* repository

image:commit-dialog.png[Commit dialog]

link:index.html[Git Exercises]