mirror of
https://github.com/NixOS/nixpkgs.git
synced 2024-12-18 11:44:07 +00:00
e27e30204b
Motivated from seeing people starting to migrate packages manually when it shouldn't be necessary or done differently.
118 lines
4.0 KiB
Markdown
118 lines
4.0 KiB
Markdown
# Name-based package directories
|
|
|
|
The structure of this directory maps almost directly to top-level package attributes.
|
|
This is the recommended way to add new top-level packages to Nixpkgs [when possible](#limitations).
|
|
|
|
## Example
|
|
|
|
The top-level package `pkgs.some-package` may be declared by setting up this file structure:
|
|
|
|
```
|
|
pkgs
|
|
└── by-name
|
|
├── so
|
|
┊ ├── some-package
|
|
┊ └── package.nix
|
|
|
|
```
|
|
|
|
Where `some-package` is the package name and `so` is the lowercased 2-letter prefix of the package name.
|
|
|
|
The `package.nix` may look like this:
|
|
|
|
```nix
|
|
# A function taking an attribute set as an argument
|
|
{
|
|
# Get access to top-level attributes for use as dependencies
|
|
lib,
|
|
stdenv,
|
|
libbar,
|
|
|
|
# Make this derivation configurable using `.override { enableBar = true }`
|
|
enableBar ? false,
|
|
}:
|
|
|
|
# The return value must be a derivation
|
|
stdenv.mkDerivation {
|
|
# ...
|
|
buildInputs =
|
|
lib.optional enableBar libbar;
|
|
}
|
|
```
|
|
|
|
You can also split up the package definition into more files in the same directory if necessary.
|
|
|
|
Once defined, the package can be built from the Nixpkgs root directory using:
|
|
```
|
|
nix-build -A some-package
|
|
```
|
|
|
|
See the [general package conventions](../README.md#conventions) for more information on package definitions.
|
|
|
|
### Changing implicit attribute defaults
|
|
|
|
The above expression is called using these arguments by default:
|
|
```nix
|
|
{
|
|
lib = pkgs.lib;
|
|
stdenv = pkgs.stdenv;
|
|
libbar = pkgs.libbar;
|
|
}
|
|
```
|
|
|
|
But the package might need `pkgs.libbar_2` instead.
|
|
While the function could be changed to take `libbar_2` directly as an argument,
|
|
this would change the `.override` interface, breaking code like `.override { libbar = ...; }`.
|
|
So instead it is preferable to use the same generic parameter name `libbar`
|
|
and override its value in [`pkgs/top-level/all-packages.nix`](../top-level/all-packages.nix):
|
|
|
|
```nix
|
|
libfoo = callPackage ../by-name/so/some-package/package.nix {
|
|
libbar = libbar_2;
|
|
};
|
|
```
|
|
|
|
## Manual migration guidelines
|
|
|
|
Most packages are still defined in `all-packages.nix` and the [category hierarchy](../README.md#category-hierarchy).
|
|
Please hold off migrating your maintained packages to this directory.
|
|
|
|
1. An automated migration for the majority of packages [is being worked on](https://github.com/NixOS/nixpkgs/pull/211832).
|
|
In order to save on contributor and reviewer time, packages should only be migrated manually afterwards if they couldn't be migrated automatically.
|
|
|
|
1. Manual migrations should only be lightly encouraged if the relevant code is being worked on anyways.
|
|
For example with a package update or refactoring.
|
|
|
|
1. Manual migrations should not remove definitions from `all-packages.nix` with custom arguments.
|
|
That is a backwards-incompatible change because it changes the `.override` interface.
|
|
Such packages may still be moved to `pkgs/by-name` however, while keeping the definition in `all-packages.nix`.
|
|
See also [changing implicit attribute defaults](#changing-implicit-attribute-defaults).
|
|
|
|
## Limitations
|
|
|
|
There's some limitations as to which packages can be defined using this structure:
|
|
|
|
- Only packages defined using `pkgs.callPackage`.
|
|
This excludes packages defined using `pkgs.python3Packages.callPackage ...`.
|
|
|
|
Instead use the [category hierarchy](../README.md#category-hierarchy) for such attributes.
|
|
|
|
- Only top-level packages.
|
|
This excludes packages for other package sets like `pkgs.pythonPackages.*`.
|
|
|
|
Refer to the definition and documentation of the respective package set to figure out how such packages can be declared.
|
|
|
|
## Validation
|
|
|
|
CI performs [certain checks](../test/nixpkgs-check-by-name/README.md#validity-checks) on the `pkgs/by-name` structure.
|
|
This is done using the [`nixpkgs-check-by-name` tool](../test/nixpkgs-check-by-name).
|
|
The version of this tool used is the one that corresponds to the NixOS channel of the PR base branch.
|
|
See [here](../../.github/workflows/check-by-name.yml) for details.
|
|
|
|
The tool can be run locally using
|
|
|
|
```bash
|
|
nix-build -A tests.nixpkgs-check-by-name
|
|
result/bin/nixpkgs-check-by-name .
|
|
```
|