home-manager/modules/default.nix
Robert Hensing 26e72d85e6
home-manager: set module class to "homeManager"
This enables a module system feature documented here:
https://nixos.org/manual/nixpkgs/stable/index.html#module-system-lib-evalModules-param-class

For example, it allows a mistake to be caught, which is loading a
NixOS module into home-manager. This only works when the offending
module declares what it's for with a `_class` attribute.

It is not expected that users declare the `_type`, because the payoff
is small. It is only expected to be set by generic code, such as
functions or libraries that help with the "publishing" of modules
(e.g. flake-parts, flake-utils).

The class feature has been available in the module system since
https://github.com/NixOS/nixpkgs/pull/197547, merged May 6, 2023. It
has been part of all releases since 23.05-beta. The last NixOS release
that did _not_ support it has been end-of-life for close to a year
now.

Example:

    (lib.homeManagerConfiguration {
      pkgs = nixpkgs.legacyPackages.x86_64-linux;
      modules = [{ _class = "nixos"; imports = [ ./foo.nix ]; }];
    }).activation-script

Corresponding error:

    error: The module <unknown-file> was imported into homeManager instead of nixos.

(`<unknown-file>` can be improved by also setting `_file`, if known; a
much older feature)

PR #5339
2024-04-27 09:28:21 +02:00

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{ configuration, pkgs, lib ? pkgs.lib
# Whether to check that each option has a matching declaration.
, check ? true
# Extra arguments passed to specialArgs.
, extraSpecialArgs ? { } }:
with lib;
let
collectFailed = cfg:
map (x: x.message) (filter (x: !x.assertion) cfg.assertions);
showWarnings = res:
let f = w: x: builtins.trace "warning: ${w}" x;
in fold f res res.config.warnings;
extendedLib = import ./lib/stdlib-extended.nix lib;
hmModules = import ./modules.nix {
inherit check pkgs;
lib = extendedLib;
};
rawModule = extendedLib.evalModules {
modules = [ configuration ] ++ hmModules;
class = "homeManager";
specialArgs = { modulesPath = builtins.toString ./.; } // extraSpecialArgs;
};
moduleChecks = raw:
showWarnings (let
failed = collectFailed raw.config;
failedStr = concatStringsSep "\n" (map (x: "- ${x}") failed);
in if failed == [ ] then
raw
else
throw ''
Failed assertions:
${failedStr}'');
withExtraAttrs = rawModule:
let module = moduleChecks rawModule;
in {
inherit (module) options config;
activationPackage = module.config.home.activationPackage;
# For backwards compatibility. Please use activationPackage instead.
activation-script = module.config.home.activationPackage;
newsDisplay = rawModule.config.news.display;
newsEntries = sort (a: b: a.time > b.time)
(filter (a: a.condition) rawModule.config.news.entries);
inherit (module._module.args) pkgs;
extendModules = args: withExtraAttrs (rawModule.extendModules args);
};
in withExtraAttrs rawModule