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Fix including the overlay twice exploding nixos-option by making it idempotent

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This commit is contained in:
jade 2024-06-05 21:15:44 -07:00
parent b4b38e6b5f
commit 4e25f1ab68
2 changed files with 63 additions and 40 deletions
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32
overlay.nix
View file

@ -54,9 +54,26 @@ let
inherit (prev) lib;
prefetch-npm-deps-args = lib.functionArgs prev.prefetch-npm-deps.override;
in
override_2_18 //
{
warning = ''
warning: You have the lix overlay included into a nixpkgs import twice,
perhaps due to the NixOS module being included twice, or because of using
pkgs.nixos and also including it in imports, or perhaps some unknown
machinations of a complicated flake library.
This is completely harmless since we have no-op'd the second one if you are
seeing this message, but it would be a small style improvement to fix
it :)
P.S. If you had some hack to fix nixos-option build failures in your
configuration, that was caused by including an older version of the lix
overlay twice, which is now mitigated if you see this message, so you can
delete that.
P.P.S. This Lix has super catgirl powers.
'';
maybeWarnDuplicate = x: if final.lix-overlay-present > 1 then builtins.trace warning x else x;
overlay = override_2_18 // {
lix-overlay-present = 1;
# used for things that one wouldn't necessarily want to update, but we
# nevertheless shove it in the overlay and fixed-point it in case one *does*
# want to do that.
@ -64,7 +81,7 @@ override_2_18 //
nixVersions = prev.nixVersions // rec {
# FIXME: do something less scuffed
nix_2_18 = lixPkg;
nix_2_18 = maybeWarnDuplicate lixPkg;
stable = nix_2_18;
nix_2_18_upstream = prev.nixVersions.nix_2_18;
};
@ -95,4 +112,9 @@ override_2_18 //
else prev.prefetch-npm-deps;
nix-doc = prev.callPackage ./nix-doc/package.nix { withPlugin = false; };
}
};
in
# Make the overlay idempotent, since flakes passing nixos modules around by
# value and many other things make it way too easy to include the overlay
# twice
if (prev ? lix-overlay-present) then { lix-overlay-present = 2; } else overlay

1
test-nixos.nix
View file

@ -2,6 +2,7 @@
let
configs = {
it-builds = nixos ({ ... }: {
imports = [ lix-module ];
documentation.enable = false;
fileSystems."/".device = "ignore-root-device";
boot.loader.grub.enable = false;