Thank you for your interest in contributing to PyO3! All are welcome - please consider reading our [Code of Conduct](Code-of-Conduct.md) to keep our community positive and inclusive.
If you are searching for ideas how to contribute, please read the "Getting started contributing" section. Once you've found an issue to contribute to, you may find the section "Writing pull requests" helpful.
Please join in with any part of PyO3 which interests you. We use Github issues to record all bugs and ideas. Feel free to request an issue to be assigned to you if you want to work on it.
The [PyO3 Gitter channel](https://gitter.im/PyO3/Lobby) is very active with users who are new to PyO3, and often completely new to Rust. Helping them debug is a great way to get experience with the PyO3 codebase.
Helping others often reveals bugs, documentation weaknesses, and missing APIs. It's a good idea to open Github issues for these immediately so the resolution can be designed and implemented!
Issues where the solution is clear and work is not in progress use the [needs-implementer](https://github.com/PyO3/pyo3/issues?q=is%3Aissue+is%3Aopen+label%3Aneeds-implemeter) label.
Don't be afraid if the solution is not clear to you! The core PyO3 contributors will be happy to mentor you through any questions you have to help you write the solution.
PyO3 has a user guide (using mdbook) as well as the usual Rust API docs. The aim is for both of these to be detailed, easy to understand, and up-to-date. Pull requests are always welcome to fix typos, change wording, add examples, etc.
There are some specific areas of focus where help is currently needed for the documentation:
- Issues requesting documentation improvements are tracked with the [documentation](https://github.com/PyO3/pyo3/issues?q=is%3Aissue+is%3Aopen+label%3Adocumentation) label.
- Not all APIs had docs or examples when they were made. The goal is to have documentation on all PyO3 APIs ([#306](https://github.com/PyO3/pyo3/issues/306)). If you see an API lacking a doc, please write one and open a PR!
- Not all `unsafe` APIs had safety notes when they made. We'd like to ensure all `unsafe` APIs are carefully explained ([#698](https://github.com/PyO3/pyo3/issues/698)). If you see an `unsafe` function missing safety notes, please write some and open a PR!
Issues which don't yet have a clear solution use the [needs-design](https://github.com/PyO3/pyo3/issues?q=is%3Aissue+is%3Aopen+label%3Aneeds-design) label.
If any of these issues interest you, please join in with the conversation on the issue! All opinions are valued, and if you're interested in going further with e.g. draft PRs to experiment with API designs, even better!
Formatting, linting and tests are checked for all Rust and Python code. In addition, all warnings in Rust code are disallowed (using `RUSTFLAGS="-D warnings"`).
Tests run with all supported Python versions with the latest stable Rust compiler, as well as for Python 3.9 with the minimum supported Rust version.
PyO3 aims to keep sufficient compatibility to make packaging Python extensions built with PyO3 feasible on most common package managers.
To keep package maintainers' lives simpler, PyO3 will commit, wherever possible, to only adjust minimum supported Rust and Python versions at the same time. This bump will only come in an `0.x` release, roughly once per year, after the oldest supported Python version reaches its end-of-life. (Check https://endoflife.date/python for a clear timetable on these.)
Below are guidelines on what compatibility all PRs are expected to deliver for each language.
### Python
PyO3 supports all oficially supported Python versions, as well as the latest PyPy3 release. All of these versions are tested in CI.
The minimum Rust version supported will be decided when the release which bumps Python and Rust versions is made. At the time, the minimum Rust version will be set no higher than the lowest Rust version shipped in the current Debian, RHEL and Alpine Linux distributions.
CI tests both the most recent stable Rust version and the minimum supported Rust version. Because of Rust's stability guarantees this is sufficient to confirm support for all Rust versions in between.
PyO3 has two sets of benchmarks for evaluating some aspects of its performance. The benchmark suite is currently very small - please feel welcome to open PRs with new benchmarks if you're interested in helping to expand it!
First, there are Rust-based benchmarks located in the `benches` subdirectory. As long as you have a nightly rust compiler available on your system, you can run these benchmarks with:
cargo +nightly bench
Second, there is a Python-based benchmark contained in the `word-count` example. You can read more about it [here](examples/word-count#benchmark).
