1# Contributing to Protocol Buffers 2 3We welcome some types of contributions to protocol buffers. This doc describes the 4process to contribute patches to protobuf and the general guidelines we 5expect contributors to follow. 6 7## What We Accept 8 9* Bug fixes with unit tests demonstrating the problem are very welcome. 10 We also appreciate bug reports, even when they don't come with a patch. 11 Bug fixes without tests are usually not accepted. 12* New APIs and features with adequate test coverage and documentation 13 may be accepted if they do not compromise backwards 14 compatibility. However there's a fairly high bar of usefulness a new public 15 method must clear before it will be accepted. Features that are fine in 16 isolation are often rejected because they don't have enough impact to justify the 17 conceptual burden and ongoing maintenance cost. It's best to file an issue 18 and get agreement from maintainers on the value of a new feature before 19 working on a PR. 20* Performance optimizations may be accepted if they have convincing benchmarks that demonstrate 21 an improvement and they do not significantly increase complexity. 22* Changes to existing APIs are almost never accepted. Stability and 23 backwards compatibility are paramount. In the unlikely event a breaking change 24 is required, it must usually be implemented in google3 first. 25* Changes to the wire and text formats are never accepted. Any breaking change 26 to these formats would have to be implemented as a completely new format. 27 We cannot begin generating protos that cannot be parsed by existing code. 28 29## Before You Start 30 31We accept patches in the form of github pull requests. If you are new to 32github, please read [How to create github pull requests](https://help.github.com/articles/about-pull-requests/) 33first. 34 35### Contributor License Agreements 36 37Contributions to this project must be accompanied by a Contributor License 38Agreement. You (or your employer) retain the copyright to your contribution, 39this simply gives us permission to use and redistribute your contributions 40as part of the project. 41 42* If you are an individual writing original source code and you're sure you 43 own the intellectual property, then you'll need to sign an [individual CLA](https://cla.developers.google.com/about/google-individual?csw=1). 44* If you work for a company that wants to allow you to contribute your work, 45 then you'll need to sign a [corporate CLA](https://cla.developers.google.com/about/google-corporate?csw=1). 46 47### Coding Style 48 49This project follows [Google’s Coding Style Guides](https://github.com/google/styleguide). 50Before sending out your pull request, please familiarize yourself with the 51corresponding style guides and make sure the proposed code change is style 52conforming. 53 54## Contributing Process 55 56Most pull requests should go to the main branch and the change will be 57included in the next major/minor version release (e.g., 3.6.0 release). If you 58need to include a bug fix in a patch release (e.g., 3.5.2), make sure it’s 59already merged to main, and then create a pull request cherry-picking the 60commits from main branch to the release branch (e.g., branch 3.5.x). 61 62For each pull request, a protobuf team member will be assigned to review the 63pull request. For minor cleanups, the pull request may be merged right away 64after an initial review. For larger changes, you will likely receive multiple 65rounds of comments and it may take some time to complete. We will try to keep 66our response time within 7-days but if you don’t get any response in a few 67days, feel free to comment on the threads to get our attention. We also expect 68you to respond to our comments within a reasonable amount of time. If we don’t 69hear from you for 2 weeks or longer, we may close the pull request. You can 70still send the pull request again once you have time to work on it. 71 72Once a pull request is merged, we will take care of the rest and get it into 73the final release. 74 75## Pull Request Guidelines 76 77* If you are a Googler, it is preferable to first create an internal CL and 78 have it reviewed and submitted. The code propagation process will deliver the 79 change to GitHub. 80* Create small PRs that are narrowly focused on addressing a single concern. 81 We often receive PRs that are trying to fix several things at a time, but if 82 only one fix is considered acceptable, nothing gets merged and both author's 83 & reviewer's time is wasted. Create more PRs to address different concerns and 84 everyone will be happy. 85* For speculative changes, consider opening an issue and discussing it first. 86 If you are suggesting a behavioral or API change, make sure you get explicit 87 support from a protobuf team member before sending us the pull request. 88* Provide a good PR description as a record of what change is being made and 89 why it was made. Link to a GitHub issue if it exists. 90* Don't fix code style and formatting unless you are already changing that 91 line to address an issue. PRs with irrelevant changes won't be merged. If 92 you do want to fix formatting or style, do that in a separate PR. 93* Unless your PR is trivial, you should expect there will be reviewer comments 94 that you'll need to address before merging. We expect you to be reasonably 95 responsive to those comments, otherwise the PR will be closed after 2-3 weeks 96 of inactivity. 97* Maintain clean commit history and use meaningful commit messages. PRs with 98 messy commit history are difficult to review and won't be merged. Use rebase 99 -i upstream/main to curate your commit history and/or to bring in latest 100 changes from main (but avoid rebasing in the middle of a code review). 101* Keep your PR up to date with upstream/main (if there are merge conflicts, 102 we can't really merge your change). 103* All tests need to be passing before your change can be merged. We recommend 104 you run tests locally before creating your PR to catch breakages early on. 105 Ultimately, the green signal will be provided by our testing infrastructure. 106 The reviewer will help you if there are test failures that seem not related 107 to the change you are making. 108 109## Reviewer Guidelines 110 111* Make sure that all tests are passing before approval. 112* Apply the "release notes: yes" label if the pull request's description should 113 be included in the next release (e.g., any new feature / bug fix). 114 Apply the "release notes: no" label if the pull request's description should 115 not be included in the next release (e.g., refactoring changes that does not 116 change behavior, integration from Google internal, updating tests, etc.). 117* Apply the appropriate language label (e.g., C++, Java, Python, etc.) to the 118 pull request. This will make it easier to identify which languages the pull 119 request affects, allowing us to better identify appropriate reviewer, create 120 a better release note, and make it easier to identify issues in the future. 121