mirror of
https://github.com/nix-community/home-manager
synced 2024-11-14 15:19:45 +01:00
221 lines
9 KiB
Markdown
221 lines
9 KiB
Markdown
# Guidelines {#sec-guidelines}
|
|
|
|
If your contribution satisfy the following rules then there is a good
|
|
chance it will be merged without too much trouble. The rules are
|
|
enforced by the Home Manager maintainers and to a lesser extent the Home
|
|
Manager CI system.
|
|
|
|
If you are uncertain how these rules affect the change you would like to
|
|
make then feel free to start a discussion in the
|
|
[#home-manager](https://webchat.oftc.net/?channels=home-manager) IRC
|
|
channel, ideally before you start developing.
|
|
|
|
## Maintain backward compatibility {#sec-guidelines-back-compat}
|
|
|
|
Your contribution should not cause another user's existing configuration
|
|
to break unless there is a very good reason and the change should be
|
|
announced to the user through an
|
|
[assertion](https://nixos.org/manual/nixos/stable/index.html#sec-assertions)
|
|
or similar.
|
|
|
|
Remember that Home Manager is used in many different environments and
|
|
you should consider how your change may effect others. For example,
|
|
|
|
- Does your change work for people that do not use NixOS? Consider
|
|
other GNU/Linux distributions and macOS.
|
|
|
|
- Does your change work for people whose configuration is built on one
|
|
system and deployed on another system?
|
|
|
|
## Keep forward compatibility in mind {#sec-guidelines-forward-compat}
|
|
|
|
The master branch of Home Manager tracks the unstable channel of
|
|
Nixpkgs, which may update package versions at any time. It is therefore
|
|
important to consider how a package update may affect your code and try
|
|
to reduce the risk of breakage.
|
|
|
|
The most effective way to reduce this risk is to follow the advice in
|
|
[Add only valuable options](#sec-guidelines-valuable-options).
|
|
|
|
## Add only valuable options {#sec-guidelines-valuable-options}
|
|
|
|
When creating a new module it is tempting to include every option
|
|
supported by the software. This is *strongly* discouraged. Providing
|
|
many options increases maintenance burden and risk of breakage
|
|
considerably. This is why only the most [important software
|
|
options](https://github.com/NixOS/rfcs/blob/master/rfcs/0042-config-option.md#valuable-options)
|
|
should be modeled explicitly. Less important options should be
|
|
expressible through an `extraConfig` escape hatch.
|
|
|
|
A good rule of thumb for the first implementation of a module is to only
|
|
add explicit options for those settings that absolutely must be set for
|
|
the software to function correctly. It follows that a module for
|
|
software that provides sensible default values for all settings would
|
|
require no explicit options at all.
|
|
|
|
If the software uses a structured configuration format like a JSON,
|
|
YAML, INI, TOML, or even a plain list of key/value pairs then consider
|
|
using a `settings` option as described in [Nix RFC
|
|
42](https://github.com/NixOS/rfcs/blob/master/rfcs/0042-config-option.md).
|
|
|
|
## Add relevant tests {#sec-guidelines-add-tests}
|
|
|
|
If at all possible, make sure to add new tests and expand existing tests
|
|
so that your change will keep working in the future. See
|
|
[Tests](#sec-tests) for more information about the Home Manager test
|
|
suite.
|
|
|
|
All contributed code *must* pass the test suite.
|
|
|
|
## Add relevant documentation {#sec-guidelines-module-maintainer}
|
|
|
|
Many code changes require changing the documentation as well. The
|
|
documentation is written in
|
|
[Nixpkgs-flavoured Markdown](https://nixos.org/manual/nixpkgs/unstable/#sec-contributing-markup).
|
|
All text is hosted in Home Manager's Git repository.
|
|
|
|
The HTML version of the manual containing both the module option
|
|
descriptions and the documentation of Home Manager can be generated and
|
|
opened by typing the following in a shell within a clone of the Home
|
|
Manager Git repository:
|
|
|
|
``` shell
|
|
$ nix-build -A docs.html
|
|
$ xdg-open ./result/share/doc/home-manager/index.html
|
|
```
|
|
|
|
When you have made changes to a module, it is a good idea to check that
|
|
the man page version of the module options looks good:
|
|
|
|
``` shell
|
|
$ nix-build -A docs.manPages
|
|
$ man ./result/share/man/man5/home-configuration.nix.5.gz
|
|
```
|
|
|
|
## Add yourself as a module maintainer {#_add_yourself_as_a_module_maintainer}
|
|
|
|
Every new module *must* include a named maintainer using the
|
|
`meta.maintainers` attribute. If you are a user of a module that
|
|
currently lacks a maintainer then please consider adopting it.
|
|
|
|
If you are present in the nixpkgs maintainer list then you can use that
|
|
entry. If you are not then you can add yourself to
|
|
`modules/lib/maintainers.nix` in the Home Manager project.
|
|
|
|
As a maintainer you are expected to respond to issues and
|
|
pull-requests associated with your module.
|
|
|
|
Maintainers are encouraged to join the IRC or Matrix channel and
|
|
participate when they have opportunity.
|
|
|
|
## Format your code {#sec-guidelines-code-style}
|
|
|
|
Make sure your code is formatted as described in [Code
|
|
Style](#sec-code-style). To maintain consistency throughout the project
|
|
you are encouraged to browse through existing code and adopt its style
|
|
also in new code.
|
|
|
|
## Format your commit messages {#sec-guidelines-commit-message-style}
|
|
|
|
Similar to [Format your code](#sec-guidelines-code-style) we encourage a
|
|
consistent commit message format as described in
|
|
[Commits](#sec-commit-style).
|
|
|
|
## Format your news entries {#sec-guidelines-news-style}
|
|
|
|
If your contribution includes a change that should be communicated to
|
|
users of Home Manager then you can add a news entry. The entry must be
|
|
formatted as described in [News](#sec-news).
|
|
|
|
When new modules are added a news entry should be included but you do
|
|
not need to create this entry manually. The merging maintainer will
|
|
create the entry for you. This is to reduce the risk of merge conflicts.
|
|
|
|
## Use conditional modules and news {#sec-guidelines-conditional-modules}
|
|
|
|
Home Manager includes a number of modules that are only usable on some
|
|
of the supported platforms. The most common example of platform specific
|
|
modules are those that define systemd user services, which only works on
|
|
Linux systems.
|
|
|
|
If you add a module that is platform specific then make sure to include
|
|
a condition in the `loadModule` function call. This will make the module
|
|
accessible only on systems where the condition evaluates to `true`.
|
|
|
|
Similarly, if you are adding a news entry then it should be shown only
|
|
to users that may find it relevant, see [News](#sec-news) for a
|
|
description of conditional news.
|
|
|
|
## Mind the license {#sec-guidelines-licensing}
|
|
|
|
The Home Manager project is covered by the MIT license and we can only
|
|
accept contributions that fall under this license, or are licensed in a
|
|
compatible way. When you contribute self written code and documentation
|
|
it is assumed that you are doing so under the MIT license.
|
|
|
|
A potential gotcha with respect to licensing are option descriptions.
|
|
Often it is convenient to copy from the upstream software documentation.
|
|
When this is done it is important to verify that the license of the
|
|
upstream documentation allows redistribution under the terms of the MIT
|
|
license.
|
|
|
|
## Commits {#sec-commit-style}
|
|
|
|
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 [seven
|
|
rules](https://chris.beams.io/posts/git-commit/#seven-rules), except for
|
|
\"Capitalize the subject line\". We also ask you to include the affected
|
|
code component or module in the first line. That is, a commit message
|
|
should follow the template
|
|
|
|
{component}: {description}
|
|
|
|
{long description}
|
|
|
|
where `{component}` refers to the code component (or module) your change
|
|
affects, `{description}` is a very brief description of your change, and
|
|
`{long description}` is an optional clarifying description. As a rare
|
|
exception, if there is no clear component, or your change affects many
|
|
components, then the `{component}` part is optional. See
|
|
[example_title](#ex-commit-message) for a commit message that fulfills
|
|
these requirements.
|
|
|
|
## Example commit {#ex-commit-message}
|
|
|
|
The commit
|
|
[69f8e47e9e74c8d3d060ca22e18246b7f7d988ef](https://github.com/nix-community/home-manager/commit/69f8e47e9e74c8d3d060ca22e18246b7f7d988ef)
|
|
contains the commit message
|
|
|
|
```
|
|
|
|
starship: allow running in Emacs if vterm is used
|
|
|
|
The vterm buffer is backed by libvterm and can handle Starship prompts
|
|
without issues.
|
|
```
|
|
|
|
which ticks all the boxes necessary to be accepted in Home Manager.
|
|
|
|
Finally, when adding a new module, say `programs/foo.nix`, we use the
|
|
fixed commit format `foo: add module`. You can, of course, still include
|
|
a long description if you wish.
|
|
|
|
## Code Style {#sec-code-style}
|
|
|
|
The code in Home Manager is formatted by the
|
|
[nixfmt](https://github.com/serokell/nixfmt/) tool and the formatting is
|
|
checked in the pull request tests. Run the `format` tool inside the
|
|
project repository before submitting your pull request.
|
|
|
|
Keep lines at a reasonable width, ideally 80 characters or less. This
|
|
also applies to string literals.
|
|
|
|
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.
|