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We welcome all contributions from the community to Capra. In particular, we are always interested in additional artifact handlers that allow Capra to use more artifacts and the sources and targets of traceability links. If you are interested in helping out by fixing bugs or want to see what other things we have planned, please check our Bugzilla.

Becoming a member of the Eclipse Community

In order to use the Eclipse development infrastructure and to contribute to Capra (and other Eclipse projects), it is necessary to create an Eclipse account. With this account, you will be able to log in to the different services (such as Bugzilla, the Eclipse Wiki, or Hudson) and push code changes to Gerrit.

After you have created the account, you need to sign the Eclipse Committer Agreement (ECA). Depending on whether you work on your own time or for a company, different conditions apply. Please familiarise yourself with the legal issues, ask your employer for help if required, and then sign the ECA here.

Cloning from Git/Gerrit

Instead of using the Git repository listed above, use the Gerrit repository. You can copy the SSH or HTTPS links from the Capra Gerrit page. This will allow you to push your changes to Gerrit where the project committers can review them before adding them to the codebase.

  • Switch to the Git Perspective, select Clone a Git Repository (icon with a blue arrow), then select Gerrit and follow the wizard.
  • Import all projects into your work space
  • Create a branch based on the develop branch. All development should be based on this branch, following the GitFlow approach. Your local changes should go into your own branch. We suggest to use the format <username>/feature/<feature-name>. Instead of `feature`, other identifiers such as fix can be used.

Sharing your Idea with the Community

We keep track of the features for Capra in our Bugzilla. If you plan to contribute your own features, please open a bug in the correct component there. The bug summary should contain the "[feature]" keyword so we know that this is not indeed a bug report. Please provide a short summary and a description of what you are doing. Use the comments of the bug to describe your progress. Other members of the community might engage you for discussions, so please take their opinions into account and react to their suggestions and feedback.

Building and Testing

Capra uses Maven/Tycho. To check if your changes work, run maven in the root folder:

mvn clean verify

This will create binaries for Capra and run all tests. Code should only be committed if all tests passed! Since all commits will be build by our Hudson instance, which in turn uses Maven to build Capra, a failed Maven run on your machine is a good indication that your commit will not be verified.

To run Capra from within Eclipse, see the instructions on the Capra wiki page.

Handling dependencies

All dependencies introduced by new commits need to be cleared through the Eclipse IP process. That means that we need to file a Contribution Questionnaire (CQ) for each new dependency introduced. Since only committers have the right to do so, other contributors need to let us know that a new dependency has been introduced and allow us to initiate the IP process. The only exception are dependencies to bundles in the org.eclipse.* namespace. These can be used without a review.

The review process is usually not difficult, unless there is no obvious license or the code is licensed under a copyleft licenses such as GPL. Dependencies with such licenses will not be accepted by the review process, so don't even bother trying and use another library instead.

There are some things that you can do to make this process easier:

  1. Check that the dependency that you want to use is part of one of the Orbit drops. Everything in Orbit has been pre-cleared and the procedure is much easier for us. You might not find the latest version of the bundle you want to use there, but usually there is at least one that contains the most important functionality. If you need a more recent version, it is still good to know that there is an existing Orbit version since that also reduces the effort required to review the dependency.
  2. Create a bug in the Development component of Capra in Bugzilla. Preface the summary of the bug with the "[dependency]" keyword and use the bundle name and version. An example is "[Dependency] v3.0.0".
  3. In the description of the bug, mention the plugin this dependency is going to be used in and link to the appropriate Orbit drop (if applicable).
  4. Create a ZIP or JAR file that contains only the sourcecode (including any text files, xml files, etc.) of the dependency, but no other JARs or binaries. Usually, the source distribution of the bundle you want to use should do, but check that it does not contain any nested dependencies. Attach the archive to the bug.
  5. One of the project committers will take the bug and file the CQ. The link to the CQ will be posted in the bug.
  6. As soon as the CQ has been approved, the bug will be resolved. You can push your code to Gerrit as soon as all dependency issues have been resolved.

Before committing

Please make sure that all points in the following checklist are fulfilled before committing your work to a Capra repository:

  • The code is formatted according to the built-in Eclipse code formatting rules.
  • All classes and all public methods are documented.
  • Each source code file has a copyright header (see below).
  • The imports are organised.
  • All open bugs for newly introduced dependencies have been resolved (see above).

Organisation of imports and code formatting can be automated by selecting them as save actions for the Java editor in the Eclipse preferences.

Adding new source files

It is important to maintain the correct copyright messages, indicating the contributors of each file and that it is covered by the EPL. You can use automation to insert a correct copyright header.

Install the Eclipse Releng Tools. They contain the copyright tool. Use the following copyright header:

Copyright (c) ${date} Chalmers | University of Gothenburg, rt-labs and others.
All rights reserved. This program and the accompanying materials
are made available under the terms of the Eclipse Public License v1.0
which accompanies this distribution, and is available at

   Chalmers | University of Gothenburg and rt-labs - initial API and implementation and/or initial documentation

The Contributors entry can be replaced with the appropriate names. Use "Fix copyrights" from the context menu to add the copyrights to all relevant files in a project or folder.

Pushing changes to Gerrit

If all pre-requisites listed above are fulfilled, the code can be pushed to Gerrit. Please note that Gerrit combines several commits into one change that will show up using the commit message of the last commit. Make sure that this commit message actually describes the changes you are pushing. Optionally, you can squash all commits into one before pushing to Gerrit.

These are the steps to push a change to Gerrit:

  • Make sure that the code compiles and the tests run through by running mvn clean verify
  • (Optional) Squash all local commits into one
  • Make sure your commit message describes the feature you contribute
  • Sign-off the commit: add a Signed-off-by footer to the commit message. If this is missing, Gerrit will not accept your push!
  • Push your changes to Gerrit. You can either do this through Eclipse or manually on the command line with a command like this: git push ssh://<username> HEAD:refs/for/develop

Please note that it is important to use the HEAD:refs/for/develop addition which indicates that the push is to Gerrit (refs/for/) and which branch the changes should be merged to (develop).

The Sign-off needs to be in the footer of the commit message, i.e., separated from the commit message by a new line and in the same block.

Once your change has been pushed to Gerrit, one of the committers in the project will review the change and Hudson will try to build your code. You will be notified about the progress by email, using the email address you used in the Signed-off-by message. If your change is accepted, it will be merged into one of the branches in the main Git repository. If there are comments or Hudson fails to build the code, you need to make the necessary changes, amend your commit, and push again.

  • Make the necessary local changes
  • Amend last commit via git commit --amend
  • Add Gerrit Change-Id to your commit message

Change-Id and sign-off both need to be in the footer.

Additional information

More information about contributing code via Gerrit and how to use the Eclipse Git repositories can be found here:

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