home-manager/CONTRIBUTING.md

Contributing

Thanks for wanting to contribute to Home Manager! These are some guidelines to make the process as smooth as possible for both you and the Home Manager developers.

If you are only looking to report a problem then it is sufficient to read through the following section on reporting issues. If you instead want to directly contribute improvements and additions then please have a look at everything here.

Reporting an issue

If you notice a problem with Home Manager and want to report it then have a look among the already open issues, if you find one matching yours then feel free to comment on it to add any additional information you may have.

If no matching issue exists then go to the new issue page and write a description of your problem. Include as much information as you can, ideally also include relevant excerpts from your Home Manager configuration.

Contributing code

If you want to contribute code to improve Home Manager then please follow these guidelines.

Fork and create a pull request

If you have not previously forked Home Manager then you need to do that first. Have a look at GitHub's "Fork A Repo" for instructions on how to do this.

Once you have a fork of Home Manager you should create a branch starting at the most recent master. Give your branch a reasonably descriptive name. Perform your changes on this branch and when you are happy with the result push the branch to GitHub and create a pull request.

Assuming your clone is at $HOME/devel/home-manager then you can make the home-manager command use it by either

1. overriding the default path by using the -I command line option:

   home-manager -I home-manager=$HOME/devel/home-manager
   

   or

2. changing the default path by ensuring your configuration includes

   programs.home-manager.enable = true;
   programs.home-manager.path = "$HOME/devel/home-manager";
   

   and running home-manager switch to activate the change. Afterwards, home-manager build and home-manager switch will use your cloned repository.

The first option is good if you only temporarily want to use your clone.

Commits

The commits in your pull request should be reasonably self-contained, that is, each commit should make sense in isolation. In particular, you will be asked to amend any commit that introduces syntax errors or similar problems even if they are fixed in a later commit.

The commit messages should follow the format

{component}: {description}

{long description}

where {component} refers to the code component (or module) your change affects, {description} is a brief description of your change, and {long description} is an optional clarifying description. Note, {description} should start with a lower case letter. As a rare exception, if there is no clear component, or your change affects many components, then the {component} part is optional.

When adding a new module, say foo.nix, we use the fixed commit format foo: add module. You can, of course, still include a long description if you wish.

In addition to the above commit message guidelines, try to follow the seven rules as much as possible.

Style guidelines

The code in Home Manager should follow the Nixpkgs syntax guidelines. Note, we prefer lowerCamelCase for variable and attribute names with the accepted exception of variables directly referencing packages in Nixpkgs which use a hyphenated style. For example, the Home Manager option services.gpg-agent.enableSshSupport references the gpg-agent package in Nixpkgs.

News

Home Manager includes a system for presenting news to the user. When making a change you, therefore, have the option to also include an associated news entry. In general, a news entry should only be added for truly noteworthy news. For example, a bug fix or new option does generally not need a news entry.

If you do have a change worthy of a news entry then please add one in news.nix but you should follow some basic guidelines:

• The entry timestamp should be in ISO-8601 format having "+00:00" as time zone. For example, "2017-09-13T17:10:14+00:00". A suitable timestamp can be produced by the command

  date --iso-8601=second --universal
  

• The entry condition should be as specific as possible. For example, if you are changing or deprecating a specific option then you could restrict the news to those users who actually use this option.

• Wrap the news message so that it will fit in the typical terminal, that is, at most 80 characters wide. Ideally a bit less.

• Unlike commit messages, news will be read without any connection to the Home Manager source code. It is therefore important to make the message understandable in isolation and to those who do not have knowledge of the Home Manager internals. To this end it should be written in more descriptive, prose like way.

• If you refer to an option then write its full attribute path. That is, instead of writing

  The option 'foo' has been deprecated, please use 'bar' instead.

  it should read

  The option 'services.myservice.foo' has been deprecated, please use 'services.myservice.bar' instead.

• A new module, say foo.nix, should always include a news entry that has a message along the lines of

  A new module is available: 'services.foo'.

  If the module is platform specific, e.g., a service module using systemd, then a condition like

  condition = hostPlatform.isLinux;
  

  should be added.