nixpkgs/nixos/tests/nixos-rebuild-specialisations.nix
Patryk Wychowaniec 2c55eba8f4
nixos: add --specialisation to nixos-rebuild
This commit fixes a papercut in nixos-rebuild where people wanting to
switch to a specialisation (or test one) were forced to manually figure
out the specialisation's path and run its activation script - since now,
there's a dedicated option to do just that.

This is a backwards-compatible change which doesn't affect the existing
behavior, which - to be fair - might still be considered sus by some
people, the painful scenario here being:

- you boot into specialisation `foo`,
- you run `nixos-rebuild switch`,
- whoops, you're no longer at specialisation `foo`, but you're rather
  brought back to the base system.

(it's especially painful for cases where specialisation is used to load
extra drivers, e.g. Nvidia, since then launching `nixos-rebuild switch`,
while forgetting that you're inside a specialisation, can cause some
parts of your system to get accidentally unloaded.)

I've tried to mitigate that by improving specialisations so that they
create a dedicated file somewhere in `/run/current-system` containing
the specialisation's name (which `nixos-rebuild` could then use as the
default value for `--specialisation`), but I haven't been able to come
up with anything working (plus it would be a breaking change then).

Closes https://github.com/NixOS/nixpkgs/issues/174065
2023-01-15 18:16:49 +01:00

131 lines
3.4 KiB
Nix

import ./make-test-python.nix ({ pkgs, ... }: {
name = "nixos-rebuild-specialisations";
nodes = {
machine = { lib, pkgs, ... }: {
imports = [
../modules/profiles/installation-device.nix
../modules/profiles/base.nix
];
nix.settings = {
substituters = lib.mkForce [ ];
hashed-mirrors = null;
connect-timeout = 1;
};
system.extraDependencies = with pkgs; [
curl
desktop-file-utils
docbook5
docbook_xsl_ns
grub2
kmod.dev
libarchive
libarchive.dev
libxml2.bin
libxslt.bin
python3Minimal
shared-mime-info
stdenv
sudo
xorg.lndir
];
virtualisation = {
cores = 2;
memorySize = 2048;
};
};
};
testScript =
let
configFile = pkgs.writeText "configuration.nix" ''
{ lib, pkgs, ... }: {
imports = [
./hardware-configuration.nix
<nixpkgs/nixos/modules/testing/test-instrumentation.nix>
];
boot.loader.grub = {
enable = true;
device = "/dev/vda";
forceInstall = true;
};
documentation.enable = false;
environment.systemPackages = [
(pkgs.writeShellScriptBin "parent" "")
];
specialisation.foo = {
inheritParentConfig = true;
configuration = { ... }: {
environment.systemPackages = [
(pkgs.writeShellScriptBin "foo" "")
];
};
};
specialisation.bar = {
inheritParentConfig = true;
configuration = { ... }: {
environment.systemPackages = [
(pkgs.writeShellScriptBin "bar" "")
];
};
};
}
'';
in
''
machine.start()
machine.succeed("udevadm settle")
machine.wait_for_unit("multi-user.target")
machine.succeed("nixos-generate-config")
machine.copy_from_host(
"${configFile}",
"/etc/nixos/configuration.nix",
)
with subtest("Switch to the base system"):
machine.succeed("nixos-rebuild switch")
machine.succeed("parent")
machine.fail("foo")
machine.fail("bar")
with subtest("Switch from base system into a specialization"):
machine.succeed("nixos-rebuild switch --specialisation foo")
machine.succeed("parent")
machine.succeed("foo")
machine.fail("bar")
with subtest("Switch from specialization into another specialization"):
machine.succeed("nixos-rebuild switch -c bar")
machine.succeed("parent")
machine.fail("foo")
machine.succeed("bar")
with subtest("Switch from specialization into the base system"):
machine.succeed("nixos-rebuild switch")
machine.succeed("parent")
machine.fail("foo")
machine.fail("bar")
with subtest("Switch into specialization using `nixos-rebuild test`"):
machine.succeed("nixos-rebuild test --specialisation foo")
machine.succeed("parent")
machine.succeed("foo")
machine.fail("bar")
with subtest("Make sure nonsense command combinations are forbidden"):
machine.fail("nixos-rebuild boot --specialisation foo")
machine.fail("nixos-rebuild boot -c foo")
'';
})