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Contributing to AlloyTools

Want to hack on AlloyTools? Here are instructions to get you started. They are probably not perfect, please let us know if anything feels wrong or incomplete.

Reporting Issues

When reporting issues on GitHub please include the version of Alloy you are using. (Look in the About box or from the command line specify -v) as well as the version of Java, java -version, and your OS details.

Build Environment

The only thing you need to build AlloyTools is Java. We use Java 8. We use Gradle to build and the repo includes gradlew which fetches the proper version of gradle.

./gradlew build - Assembles and tests the projects

We use Travis CI and the repo includes a .travis.yml file to build on Travis CI.


We use git triangular workflow. This means that no one, not even the Allow maintainers, push contributions directly into the main AlloyTools repo. All contribution come in through pull requests. So each contributor will need to fork the main Alloy repo on GitHub. All contributions are made as commits to your fork. Then you submit a pull request to have them considered for merging into the main Alloy repo.

Setting up the triangular workflow

After forking the main Alloy repo on GitHub, you can clone the main repo to your system:

git clone

This will clone the main repo to a local repo on your disk and set up the origin remote in Git. Next you will set up the the second side of the triangle to your fork repo.

cd org.alloytools.alloy
git remote add fork

Make sure to replace the URL with the SSH URL to your fork repo on GitHub. Then we configure the local repo to push your commits to the fork repo.

git config remote.pushdefault fork

So now you will pull from origin, the main repo, and push to fork, your fork repo. This option requires at least Git 1.8.4. It is also recommended that you configure

git config push.default simple

unless you are already using Git 2.0 where it is the default.

Finally, the third side of the triangle is pull requests from your fork repo to the main repo.

Make sure to set up Travis CI for your fork repo to test your commits when they are pushed to your fork repo. Travis CI will also build any pull requests you submit.

Contribution guidelines

Pull requests are always welcome

We are always thrilled to receive pull requests, and do our best to process them as fast as possible. Not sure if that typo is worth a pull request? Do it! We will appreciate it.

If your pull request is not accepted on the first try, don't be discouraged! If there's a problem with the implementation, hopefully you received feedback on what to improve.

We're trying very hard to keep Alloy lean and focused. We don't want it to do everything for everybody. This means that we might decide against incorporating a new feature. However, there might be a way to implement that feature on top of Alloy.

Create issues...

Any significant improvement should be documented as a GitHub issue before anybody starts working on it.

...but check for existing issues first!

Please take a moment to check that an issue doesn't already exist documenting your bug report or improvement proposal. If it does, it never hurts to add a quick "+1" or "I have this problem too". This will help prioritize the most common problems and requests.


Fork the repo and make changes on your fork in a feature branch:

  • If it's a bugfix branch, name it XXX-something where XXX is the number of the issue
  • If it's a feature branch, create an enhancement issue to announce your intentions, and name it XXX-something where XXX is the number of the issue.

Submit unit tests for your changes. We use junit and most projects already have a number of test cases.

Take a look at existing tests for inspiration. Run the full build including all the tests in your branch before submitting a pull request. Having Travis CI set up for your fork repo is quite a help here.

Write clean code. Universally formatted code promotes ease of writing, reading, and maintenance. We use Eclipse and all the projects have Eclipse .settings which will properly format the code. Make sure to avoid unnecessary white space changes which complicate diffs and make reviewing pull requests much more time consuming.

Pull requests descriptions should be as clear as possible and include a reference to all the issues that they address.

Pull requests must not contain commits from other users or branches.

Commit messages must start with a short summary (max. 50 chars) written in the imperative, followed by an optional, more detailed explanatory text which is separated from the summary by an empty line.

[visual] Fix position bug in visualizer

The position of nodes in a trace differ, this bug keeps the 
same node on the same place.

Code review comments may be added to your pull request. Discuss, then make the suggested modifications and push additional commits to your feature branch. Be sure to post a comment after pushing. The new commits will show up in the pull request automatically, but the reviewers will not be notified unless you comment.

Before the pull request is merged, make sure that you squash your commits into logical units of work using git rebase -i and git push -f. After every commit, the test suite should be passing. Include documentation changes in the same commit so that a revert would remove all traces of the feature or fix.

Commits that fix or close an issue should include a reference like Closes #XXX or Fixes #XXX, which will automatically close the issue when merged.

Sign your work

The sign-off is a simple line at the end of the commit message which certifies that you wrote it or otherwise have the right to pass it on as an open-source patch. The rules are pretty simple: if you can certify the below (from

Developer Certificate of Origin
Version 1.1

Copyright (C) 2004, 2006 The Linux Foundation and its contributors.
660 York Street, Suite 102,
San Francisco, CA 94110 USA

Everyone is permitted to copy and distribute verbatim copies of this
license document, but changing it is not allowed.

Developer's Certificate of Origin 1.1

By making a contribution to this project, I certify that:

(a) The contribution was created in whole or in part by me and I
    have the right to submit it under the open source license
    indicated in the file; or

(b) The contribution is based upon previous work that, to the best
    of my knowledge, is covered under an appropriate open source
    license and I have the right under that license to submit that
    work with modifications, whether created in whole or in part
    by me, under the same open source license (unless I am
    permitted to submit under a different license), as indicated
    in the file; or

(c) The contribution was provided directly to me by some other
    person who certified (a), (b) or (c) and I have not modified

(d) I understand and agree that this project and the contribution
    are public and that a record of the contribution (including all
    personal information I submit with it, including my sign-off) is
    maintained indefinitely and may be redistributed consistent with
    this project or the open source license(s) involved.

then you just add a line to end of the git commit message:

Signed-off-by: Joe Smith <>

using your real name. Sorry, no pseudonyms or anonymous contributions.

Many Git UI tools have support for adding the Signed-off-by line to the end of your commit message. This line can be automatically added by the git commit command by using the -s option.

Small patch exception

There are some exceptions to the signing requirement. Currently these are:

  • Your patch fixes spelling or grammar errors.

Merge approval

The Alloy maintainers will review your pull request and, if approved, will merge into the main repo.

How can I become a maintainer?

  • Step 1: learn the code inside out
  • Step 2: make yourself useful by contributing code, bugfixes, support etc.
  • Step 3: introduce your self to the other maintainers

Don't forget: being a maintainer is a time investment. Make sure you will have time to make yourself available. You don't have to be a maintainer to make a difference on the project!

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