mediapipe/CONTRIBUTING.md

Contributing guidelines

Pull Request Checklist

Before sending your pull requests, make sure you followed this list.

• Read contributing guidelines.
• Read Code of Conduct.
• Ensure you have signed the Contributor License Agreement (CLA).
• Check if my changes are consistent with the guidelines.
• Changes are consistent with the Coding Style.
• Run Unit Tests.

How to become a contributor and submit your own code

Contributor License Agreements

We'd love to accept your patches! Before we can take them, we have to jump a couple of legal hurdles.

Please fill out either the individual or corporate Contributor License Agreement (CLA).

• If you are an individual writing original source code and you're sure you own the intellectual property, then you'll need to sign an individual CLA.
• If you work for a company that wants to allow you to contribute your work, then you'll need to sign a corporate CLA.

Follow either of the two links above to access the appropriate CLA and instructions for how to sign and return it. Once we receive it, we'll be able to accept your pull requests.

NOTE: Only original source code from you and other people that have signed the CLA can be accepted into the main repository.

Contributing code

If you have improvements to MediaPipe, send us your pull requests! For those just getting started, GitHub has a howto.

MediaPipe team members will be assigned to review your pull requests. Once the pull requests are approved and pass continuous integration checks, a MediaPipe team member will apply ready to pull label to your change. This means we are working on getting your pull request submitted to our internal repository. After the change has been submitted internally, your pull request will be merged automatically on GitHub.

If you want to contribute but you're not sure where to start, take a look at the issues with the "contributions welcome" label. These are issues that we believe are particularly well suited for outside contributions, often because we probably won't get to them right now. If you decide to start on an issue, leave a comment so that other people know that you're working on it. If you want to help out, but not alone, use the issue comment thread to coordinate.

Contribution guidelines and standards

Before sending your pull request for review, make sure your changes are consistent with the guidelines and follow the MediaPipe coding style.

General guidelines and philosophy for contribution

• Include unit tests when you contribute new features, as they help to a) prove that your code works correctly, and b) guard against future breaking changes to lower the maintenance cost.
• Bug fixes also generally require unit tests, because the presence of bugs usually indicates insufficient test coverage.
• Keep API compatibility in mind when you change code in MediaPipe framework e.g., code in mediapipe/framework and mediapipe/calculators. Once MediaPipe has reached version 1 and we will not make non-backward-compatible API changes without a major release. Reviewers of your pull request will comment on any API compatibility issues.
• When you contribute a new feature to MediaPipe, the maintenance burden is (by default) transferred to the MediaPipe team. This means that benefit of the contribution must be compared against the cost of maintaining the feature.
• Full new features (e.g., a new op implementing a cutting-edge algorithm) typically will live in mediapipe/addons to get some airtime before decision is made regarding whether they are to be migrated to the core.

License

Include a license at the top of new files.

• C/C++ license example
• Java license example

Bazel BUILD files also need to include a license section, e.g., BUILD example.

C++ coding style

Changes to MediaPipe C++ code should conform to Google C++ Style Guide.

Use clang-tidy to check your C/C++ changes. To install clang-tidy on ubuntu:16.04, do:

apt-get install -y clang-tidy

You can check a C/C++ file by doing:

clang-format <my_cc_file> --style=google > /tmp/my_cc_file.cc
diff <my_cc_file> /tmp/my_cc_file.cc

Coding style for other languages

• Google Java Style Guide
• Google JavaScript Style Guide
• Google Shell Style Guide
• Google Objective-C Style Guide

Running sanity check

If you have Docker installed on your system, you can perform a sanity check on your changes by running the command:

mediapipe/tools/ci_build/ci_build.sh CPU mediapipe/tools/ci_build/ci_sanity.sh

This will catch most license, Python coding style and BUILD file issues that may exist in your changes.