From 2f5e4c57d8b5273dc62daa66f617082ea71aab5c Mon Sep 17 00:00:00 2001
From: "Casper V. Kristensen" <casper@vkristensen.dk>
Date: Sat, 11 Nov 2023 00:49:55 +0100
Subject: [PATCH] align nix flake registry with flake.lock

---
 modules/base/system.nix | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/modules/base/system.nix b/modules/base/system.nix
index b499dc3..9dca3cf 100644
--- a/modules/base/system.nix
+++ b/modules/base/system.nix
@@ -1,4 +1,4 @@
-{ config, nix-index-database, lib, pkgs, ... }: {
+{ config, nix-index-database, nixpkgs-unstable, nixpkgs, lib, pkgs, ... }: {
   imports = [
     nix-index-database.nixosModules.nix-index
   ];
@@ -14,6 +14,18 @@
       auto-optimise-store = true;
       experimental-features = [ "nix-command" "flakes" ];
     };
+
+    # The nix registry is used to refer to flakes using symbolic identifiers
+    # when running commands such as `nix run nixpkgs#hello`. By default,
+    # the global registry from [1] is used, which aliases `nixpkgs` to the
+    # nixpkgs-unstable branch. We overwrite the default global `nixpkgs`
+    # registry with one which refers to the same nixpkgs as the rest of
+    # the system, aligning it with flake.lock.
+    # [1] https://github.com/NixOS/flake-registry/blob/master/flake-registry.json
+    registry = {
+      nixpkgs.flake = nixpkgs;
+      nixpkgs-unstable.flake = nixpkgs-unstable;
+    };
   };
   nixpkgs.config.allowUnfree = true;