Please note that this project is released with a [Contributor Code of Conduct](CODE_OF_CONDUCT.md). By contributing to this project you agree to abide by its terms.
If you have any questions that aren't addressed in this document, please don't hesitate to open an issue or drop into our [Discord server](https://discord.gg/8Jzqu3T)! 💬
## Glossary
- **Module**: A component in the prompt giving information based on contextual information from your OS. For example, the `nodejs` module shows the version of NodeJS that is currently installed on your computer, if your current directory is a NodeJS project.
- **Segment**: Smaller sub-components that compose a module. For example, the `symbol` segment in the `nodejs` module contains the character that is shown before the version number (`⬢` by default).
## Philosophy
We aim to make starship as fast, robust and reliable as possible, while also allowing for extensive customization. We do so by leveraging Rust's inherent safety and with thorough cross-platform testing. We also do our best to eliminate unnecessary work when displaying the prompt by reducing repeated work and by using caching to our favor.
If you spot anywhere that we could trim some time or reduce the prompt's workload, we will gladly accept new issues or PRs! 😄
## Architecture
The project begins in [`main.rs`](src/main.rs), where the appropriate `print::` method is called based on which arguments are given to [clap](https://crates.io/crates/clap). When printing the full prompt, we use [rayon](https://crates.io/crates/rayon) to parallelize the computation of modules.
Any styling that is applied to a module is inherited by its segments. Module prefixes and suffixes by default don't have any styling applied to them.
## Logging
Debug logging in starship is done with [pretty_env_logger](https://crates.io/crates/pretty_env_logger).
To run starship with debug logs, set the `RUST_LOG` environment variable to the log level needed.
For example, to enable the trace logs, run the following:
```sh
# Run installed starship
RUST_LOG=starship=trace starship
# Run with cargo
RUST_LOG=starship=trace cargo run
```
## Linting
Starship source files are linted with [clippy](https://crates.io/crates/clippy). Clippy will be ran as part of CI. Linting errors will fail a build, so it is suggested that you run Clippy locally:
```sh
rustup component add clippy
cargo clippy
```
## Formatting
Starship source files are formatted with [rustfmt](https://crates.io/crates/rustfmt-nightly). Rustfmt will be ran as part of CI. Unformatted code will fail a build, so it is suggested that you run rustfmt locally:
```sh
rustup component add rustfmt
cargo fmt
```
## Testing
Testing is critical to making sure starship works as intended on systems big and small. Starship interfaces with many applications and system APIs when generating the prompt, so there's a lot of room for bugs to slip in.
Unit tests are written using the built-in Rust testing library in the same file as the implementation, as is traditionally done in Rust codebases. These tests can be run with `cargo test`.
Unit tests should be fully isolated, only testing a given function's expected output given a specific input, and should be reproducible on any machine. Unit tests should not expect the computer running them to be in any particular state. This includes having any applications pre-installed, having any environment variables set, etc.
The previous point should be emphasized: even seemingly innocuous ideas like "if we can see the directory, we can read it" or "nobody will have their home directory be a git repo" have bitten us in the past. Having even a single test fail can completely break installation on some platforms, so be careful with tests!
Integration tests should test full modules or the entire prompt. All integration tests that expect the testing environment to have pre-existing state or tests that make permanent changes to the filesystem should have the `#[ignore]` attribute added to them. All tests that don't depend on any preexisting state will be run alongside the unit tests with `cargo test`.
For tests that depend on having preexisting state, whatever needed state will have to be added to the project's GitHub Actions workflow file([`.github/workflows/workflow.yml`](.github/workflows/workflow.yml)).
Any tests that depend on File I/O should use [`sync_all()`](https://doc.rust-lang.org/std/fs/struct.File.html#method.sync_all) when creating files or after writing to files.
Any tests that use `tempfile::tempdir` should take care to call `dir.close()` after usage to ensure the lifecycle of the directory can be reasoned about.
Any tests that use `create_fixture_repo()` should remove the returned directory after usage with `remove_dir_all::remove_dir_all()`.
