Michael Thomsen edited this page Jan 12, 2017 · 14 revisions

Want to contribute? Great! First, read this page (including the small print at the end).

Ways you can contribute

You can help the Dart project in many ways, in addition to contributing code. For example, you can report bugs, ask and answer Dart questions on StackOverflow, and improve the documentation.

If you'd like to improve the documentation, you have three options:

Before you contribute

Before we can use your code, you must sign the Google Individual Contributor License Agreement (CLA), which you can do online. The CLA is necessary mainly because you own the copyright to your changes, even after your contribution becomes part of our codebase, so we need your permission to use and distribute your code. We also need to be sure of various other things—for instance that you'll tell us if you know that your code infringes on other people's patents. You don't have to sign the CLA until after you've submitted your code for review and a member has approved it, but you must do it before we can put your code into our codebase.

Before you start working on a larger contribution, you should get in touch with us first through the Dart Issue Tracker with your idea so that we can help out and possibly guide you. Coordinating up front makes it much easier to avoid frustration later on.

All submissions, including submissions by project members, require review. We use the same code-review tools and process as the chromium project. In order to submit a patch, you need to get the depot_tools.

We occasionally take pull requests, e.g., for comment changes, but the main flow is to use the Rietveld review system as explained below.

Getting the code

To work with the Dart code, you need to download and build the development branch. Active development of Dart takes place on the master branch, from which we push "green" versions that have passed all tests to dev branch. Complete instructions are found at Getting The Source

Starting a patch with git

Note: you can be in any branch when you run git new-branch

git new-branch <feature name>
<write code>
git commit
<write code...>
git commit

Keeping your branch updated with origin/master

As you work, and before you send a patch for review, you should ensure your branch is merging cleanly to origin/master.

There are multiple ways to do this, but we generally recommend running:

git rebase-update

Note: you can run this command from any branch.

This command will fetch origin/master, rebase all your open branches, and delete cleanly merged branches.

Your local workflow may vary.

Uploading the patch for review

Upload the patch for review:

git cl upload

The above command returns a URL for the review. Attach this review to your issue in

If you have commit access, when the review is done and the patch is good to go, commit the patch:

git cl land

If you do not have commit access, a Dart engineer will commit for you, assuming the patch is reviewed and accepted.

More detailed instructions for the git cl tools available on

For committers: Merging external contributions

If the author of a patch is not a committer, they will need help landing the patch. Once a patch gets an LGTM, it's easy for a committer to merge it in.

git checkout master
git cl patch _patch_number_
git cl land -c "Jane Dev <>"

Coding style

The source code of Dart follows the:

You should familiarize yourself with those guidelines.

All files in the Dart project must start with the following header. If you add a new file please also add this. The year should be a single number (not a range; don't use "2011-2012", even if the original code did). If you edit an existing file you don't have to update the year

// Copyright (c) 2015, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

The small print

Contributions made by corporations are covered by a different agreement than the one above, the Software Grant and Corporate Contributor License Agreement.