refactor: pull bootstap into regular shell for ease of use

flake.nix

@@ -89,13 +89,6 @@
             alejandra
           ];
         };
-
-        # Shell for bootstrapping flake-enabled nix and home-manager
-        bootstrap = pkgs.mkShell {
-          # Enable experimental features without having to specify the argument
-          NIX_CONFIG = "experimental-features = nix-command flakes";
-          nativeBuildInputs = with pkgs; [nix home-manager git];
-        };
       }
     );
 

nixpkgs.nix

@@ -0,0 +1,9 @@
+# A nixpkgs instance that is grabbed from the pinned nixpkgs commit in the lock file
+# This is useful to avoid using channels when using legacy nix commands
+let
+  lock = (builtins.fromJSON (builtins.readFile ./flake.lock)).nodes.nixpkgs.locked;
+in
+  import (fetchTarball {
+    url = "https://github.com/nixos/nixpkgs/archive/${lock.rev}.tar.gz";
+    sha256 = lock.narHash;
+  })

shell.nix

@@ -0,0 +1,8 @@
+# Shell for bootstrapping flake-enabled nix and home-manager
+{pkgs ? (import ./nixpkgs.nix) {}}: {
+  bootstrap = pkgs.mkShell {
+    # Enable experimental features without having to specify the argument
+    NIX_CONFIG = "experimental-features = nix-command flakes";
+    nativeBuildInputs = with pkgs; [nix home-manager git];
+  };
+}