nixpkgs/nixos/modules/misc/nixpkgs.nix
Eelco Dolstra 73f32d0375 Show precise error messages in option merge failures
For instance, if time.timeZone is defined multiple times, you now get
the error message:

  error: user-thrown exception: The unique option `time.timeZone' is defined multiple times, in `/etc/nixos/configurations/misc/eelco/x11vnc.nix' and `/etc/nixos/configuration.nix'.

while previously you got:

  error: user-thrown exception: Multiple definitions of string. Only one is allowed for this option.

and only an inspection of the stack trace gave a clue as to what
option caused the problem.
2013-10-28 22:45:57 +01:00

74 lines
2 KiB
Nix

{ config, pkgs, ... }:
with pkgs.lib;
let
isConfig = x:
builtins.isAttrs x || builtins.isFunction x;
optCall = f: x:
if builtins.isFunction f
then f x
else f;
mergeConfig = lhs_: rhs_:
let
lhs = optCall lhs_ { inherit pkgs; };
rhs = optCall rhs_ { inherit pkgs; };
in
lhs // rhs //
optionalAttrs (lhs ? packageOverrides) {
packageOverrides = pkgs:
optCall lhs.packageOverrides pkgs //
optCall (attrByPath ["packageOverrides"] ({}) rhs) pkgs;
};
configType = mkOptionType {
name = "nixpkgs config";
check = traceValIfNot isConfig;
merge = args: fold mergeConfig {};
};
in
{
options = {
nixpkgs.config = mkOption {
default = {};
example = literalExample
''
{ firefox.enableGeckoMediaPlayer = true;
packageOverrides = pkgs: {
firefox60Pkgs = pkgs.firefox60Pkgs.override {
enableOfficialBranding = true;
};
};
}
'';
type = configType;
description = ''
The configuration of the Nix Packages collection. (For
details, see the Nixpkgs documentation.) It allows you to set
package configuration options, and to override packages
globally through the <varname>packageOverrides</varname>
option. The latter is a function that takes as an argument
the <emphasis>original</emphasis> Nixpkgs, and must evaluate
to a set of new or overridden packages.
'';
};
nixpkgs.system = mkOption {
default = pkgs.stdenv.system;
description = ''
Specifies the Nix platform type for which NixOS should be built.
If unset, it defaults to the platform type of your host system
(<literal>${builtins.currentSystem}</literal>).
Specifying this option is useful when doing distributed
multi-platform deployment, or when building virtual machines.
'';
};
};
}