NixOS

NixOS is a Linux distribution based on the purely functional package management system Nix. More information can be found at https://nixos.org/nixos and in the manual in doc/manual.

Testing changes

You can add new module to your NixOS configuration file (usually it’s /etc/nixos/configuration.nix). And do sudo nixos-rebuild test -I nixpkgs=<path to your local nixpkgs folder> --fast.

Commit conventions

Make sure you read about the commit conventions common to Nixpkgs as a whole.
Format the commit messages in the following way:
```
nixos/(module): (init module | add setting | refactor | etc)

(Motivation for change. Link to release notes. Additional information.)
```
Examples:
- nixos/hydra: add bazBaz option
  
  Dual baz behavior is needed to do foo.
- nixos/nginx: refactor config generation
  
  The old config generation system used impure shell scripts and could break in specific circumstances (see #1234).

Reviewing contributions

When changing the bootloader installation process, extra care must be taken. Grub installations cannot be rolled back, hence changes may break people’s installations forever. For any non-trivial change to the bootloader please file a PR asking for review, especially from @edolstra.

Module updates

Module updates are submissions changing modules in some ways. These often contains changes to the options or introduce new options.

Reviewing process:

Ensure that the module maintainers are notified.
- CODEOWNERS will make GitHub notify users based on the submitted changes, but it can happen that it misses some of the package maintainers.
Ensure that the module tests, if any, are succeeding.
- You may invoke OfBorg with @ofborg test <module> to build nixosTests.<module>
Ensure that the introduced options are correct.
- Type should be appropriate (string related types differs in their merging capabilities, loaOf and string types are deprecated).
- Description, default and example should be provided.
Ensure that option changes are backward compatible.
- mkRenamedOptionModuleWith provides a way to make renamed option backward compatible.
- Use lib.versionAtLeast config.system.stateVersion "24.05" on backward incompatible changes which may corrupt, change or update the state stored on existing setups.
Ensure that removed options are declared with mkRemovedOptionModule.
Ensure that changes that are not backward compatible are mentioned in release notes.
Ensure that documentations affected by the change is updated.

Sample template for a module update review is provided below.

##### Reviewed points

- [ ] changes are backward compatible
- [ ] removed options are declared with `mkRemovedOptionModule`
- [ ] changes that are not backward compatible are documented in release notes
- [ ] module tests succeed on ARCHITECTURE
- [ ] options types are appropriate
- [ ] options description is set
- [ ] options example is provided
- [ ] documentation affected by the changes is updated

##### Possible improvements

##### Comments

New modules

New modules submissions introduce a new module to NixOS.