29027fd1e1
Using pkgs.lib on the spine of module evaluation is problematic because the pkgs argument depends on the result of module evaluation. To prevent an infinite recursion, pkgs and some of the modules are evaluated twice, which is inefficient. Using ‘with lib’ prevents this problem.
49 lines
1.2 KiB
Nix
49 lines
1.2 KiB
Nix
# This module generates the nixos-checkout script, which replaces the
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# Nixpkgs source trees in /etc/nixos/nixpkgs with a Git checkout.
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{ config, lib, pkgs, ... }:
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with lib;
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let
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nixosCheckout = pkgs.substituteAll {
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name = "nixos-checkout";
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dir = "bin";
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isExecutable = true;
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src = pkgs.writeScript "nixos-checkout"
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''
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#! ${pkgs.stdenv.shell} -e
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if [ "$1" == "-h" ] || [ "$1" == "--help" ]; then
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echo "Usage: `basename $0` [PREFIX]. See NixOS Manual for more info."
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exit 0
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fi
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prefix="$1"
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if [ -z "$prefix" ]; then prefix=/etc/nixos; fi
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mkdir -p "$prefix"
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cd "$prefix"
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if [ -z "$(type -P git)" ]; then
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echo "installing Git..."
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nix-env -iA nixos.pkgs.git || nix-env -i git
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fi
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# Move any old nixpkgs directories out of the way.
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backupTimestamp=$(date "+%Y%m%d%H%M%S")
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if [ -e nixpkgs -a ! -e nixpkgs/.git ]; then
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mv nixpkgs nixpkgs-$backupTimestamp
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fi
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# Check out the NixOS and Nixpkgs sources.
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git clone git://github.com/NixOS/nixpkgs.git nixpkgs
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'';
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};
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in
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{
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environment.systemPackages = [ nixosCheckout ];
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}
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