This is just a short guide for setting up a development environment. Make sure to also read the contribution guidelines of nixpkgs and home-manager

Getting started

First, create a fork on github, then clone your repo:

git clone [email protected]:LilleAila/nixpkgs --depth=1
cd nixpkgs

Configure remotes

Set the upstream repo as a remote to your local repo. For nixpkgs, run this command:

git remote add upstream https://github.com/NixOS/nixpkgs

and for home-manager, run this

git remote add upstream https://github.com/nix-community/home-manager

, then fetch the upstream remote with

git fetch --depth=1 upstream

Set up your development environment

After cloning the repo to your local machine, you want to configure your development environment. The easiest way to do this is using direnv. Add the following to .git/info/exclude:

shell.nix
.envrc
.direnv

This file works the same as .gitignore, the only difference being that it doesn’t get included in commits.

Now, you want to configure the devshell. Create a shell.nix, and enable direnv:

# shell.nix
{ pkgs ? import <nixpkgs> { }, }:
pkgs.mkShell {
  nativeBuildInputs = with pkgs; [
    nixfmt-rfc-style
    nixd
  ];
}

echo "use nix" > .envrc && direnv allow

If you are contributing to home-manager, you want to use nixfmt-classic instead of nixfmt-rfc-style as the formatter.

Adding your changes

Create a new branch based on upstream/master

git checkout -b descriptive-branch-name upstream/master

Oh no, I forgot to make a new branch!

Run the following commands to move the changes to the correct place:

git branch the-new-branch
git reset origin/master --hard
git checkout the-new-branch

Testing your changes

In your NixOS configuration, change the input url in your flake.nix to the path of your local repo, for example

inputs.home-manager = {
  url = "/home/olai/devel/home-manager/";
  inputs.nixpkgs.follows = "nixpkgs";
};

Creating a pull request

Make sure your commit messages are formatted like this

{component}: {short description}

{long description}

, then push your changes to your fork with

git push origin branch-name

Use the github interface to create a pull request, making sure the name is also formatted as {component}: {short description}.