Development environment

Developer shell

To enter the developer shell, run:

nix develop

To automatically enter the developer shell upon entering the project directory with direnv, run:

direnv allow

pre-commit

The default developer shell leverages pre-commit hooks to simplify the process of reaching minimum quality standards for casual contributors. This means applying code formatters, and scanning for things like unused variables which should be removed.

By default, once you have entered the developer shell, pre-commit runs automatically just before you create a commit. This will only look at the files which are about to be committed.

You can also run it manually against all files:

pre-commit run --all-files

This is useful if a commit was created outside of the developer shell, and you need to apply pre-commit to your previous changes.

Note that there is also a flake output, .#checks.«system».git-hooks, which always runs against all files but does not have access to apply changes. This is used in GitHub Actions to ensure that pre-commit has been applied.

stylix-check

When a pull request is opened, we use GitHub Actions to build everything under .#checks. This includes the previously mentioned .#checks.«system».git-hooks, and every testbed.

You might sometimes find it useful to run these same checks locally. The built in nix flake check command does this, however it can be quite slow compared to the script we use on GitHub Actions.

To use the same script that we use, you can run this command within the developer shell:

stylix-check

This is based on nix-fast-build.