diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md new file mode 100644 index 00000000..37c1a9d5 --- /dev/null +++ b/CONTRIBUTING.md @@ -0,0 +1,93 @@ +# Contributing to Rand + +Thank you for your interest in contributing to Rand! + +The following is a list of notes and tips for when you want to contribute to +Rand with a pull request. + +If you want to make major changes, it is usually best to open an issue to +discuss the idea first. + +Rand doesn't (yet) use rustfmt. It is best to follow the style of the +surrounding code, and try to keep an 80 character line limit. + + +## Documentation + +We especially welcome documentation PRs. + +As of Rust 1.25 there are differences in how stable and nightly render +documentation links. Make sure it works on stable, then nightly should be good +too. One Travis CI build checks for dead links using `cargo-deadlinks`. If you +want to run the check locally: +```sh +cargo install cargo-deadlinks +# It is recommended to remove left-over files from previous compilations +rm -rf /target/doc +cargo doc --no-deps +cargo deadlinks --dir target/doc +``` + +When making changes to code examples in the documentation, make sure they build +with: +```sh +cargo test --doc +``` + +A helpful command to rebuild documentation automatically on save (only works on +Linux): +``` +while inotifywait -r -e close_write src/ rand_core/; do cargo doc; done +``` + + +## Testing + +Rand already contains a number of unit tests, but could use more. Also the +existing ones could use clean-up. Any work on the tests is appreciated. + +Not every change or new bit of functionality requires tests, but if you can +think of a test that adds value, please add it. + +Depending on the code you change, test with one of: +```sh +cargo test +cargo test --package rand_core +# Test log, serde and 128-bit support +cargo test --features serde1,log,nightly +``` + +We want to be able to not only run the unit tests with `std` available, but also +without. Because `thread_rng()` and `FromEntropy` are not available without the +`std` feature, you may have to disable a new test with `#[cfg(feature="std")]`. +In other cases using `::test::rng` with a constant seed is a good option: +```rust +let mut rng = ::test::rng(528); // just pick some number +``` + +Only the unit tests should work in `no_std` mode, we don't want to complicate +the doc-tests. Run the tests with: +```sh +# Test no_std support +cargo test --lib --no-default-features +cargo test --package rand_core --no-default-features + +# Test no_std+alloc support; requires nightly +cargo test --lib --no-default-features --features alloc +``` + + +## Benchmarking + +A lot of code in Rand is performance-sensitive, most of it is expected to be +used in hot loops in some libraries/applications. If you change code in the +`rngs`, `prngs` or `distributions` modules, especially when you see an 'obvious +cleanup', make sure the benchmarks do not regress. It is nice to report the +benchmark results in the PR (or to report nothing's changed). + +```sh +# Benchmarks (requires nightly) +cargo bench +# Some benchmarks have a faster path with i128_support +cargo bench --features=nightly +```