nixpkgs/nixos/lib/eval-config.nix
Graham Christensen ca7391daf2
Merge pull request #46341 from obsidiansystems/fix-46320
nixpkgs module: Fix defaulting of `localSystem` and `system`
2018-09-08 09:16:41 -04:00

67 lines
2.3 KiB
Nix

# From an end-user configuration file (`configuration.nix'), build a NixOS
# configuration object (`config') from which we can retrieve option
# values.
# !!! Please think twice before adding to this argument list!
# Ideally eval-config.nix would be an extremely thin wrapper
# around lib.evalModules, so that modular systems that have nixos configs
# as subcomponents (e.g. the container feature, or nixops if network
# expressions are ever made modular at the top level) can just use
# types.submodule instead of using eval-config.nix
{ # !!! system can be set modularly, would be nice to remove
system ? builtins.currentSystem
, # !!! is this argument needed any more? The pkgs argument can
# be set modularly anyway.
pkgs ? null
, # !!! what do we gain by making this configurable?
baseModules ? import ../modules/module-list.nix
, # !!! See comment about args in lib/modules.nix
extraArgs ? {}
, # !!! See comment about args in lib/modules.nix
specialArgs ? {}
, modules
, # !!! See comment about check in lib/modules.nix
check ? true
, prefix ? []
, lib ? import ../../lib
}:
let extraArgs_ = extraArgs; pkgs_ = pkgs;
extraModules = let e = builtins.getEnv "NIXOS_EXTRA_MODULE_PATH";
in if e == "" then [] else [(import e)];
in
let
pkgsModule = rec {
_file = ./eval-config.nix;
key = _file;
config = {
# Explicit `nixpkgs.system` or `nixpkgs.localSystem` should override
# this. Since the latter defaults to the former, the former should
# default to the argument. That way this new default could propagate all
# they way through, but has the last priority behind everything else.
nixpkgs.system = lib.mkDefault system;
_module.args.pkgs = lib.mkIf (pkgs_ != null) (lib.mkForce pkgs_);
};
};
in rec {
# Merge the option definitions in all modules, forming the full
# system configuration.
inherit (lib.evalModules {
inherit prefix check;
modules = modules ++ extraModules ++ baseModules ++ [ pkgsModule ];
args = extraArgs;
specialArgs = { modulesPath = ../modules; } // specialArgs;
}) config options;
# These are the extra arguments passed to every module. In
# particular, Nixpkgs is passed through the "pkgs" argument.
extraArgs = extraArgs_ // {
inherit modules baseModules;
};
inherit (config._module.args) pkgs;
}