From 1318be736262057168d6ccd17ad870fdfe7d6654 Mon Sep 17 00:00:00 2001
From: Will Forman <wf8581@gmail.com>
Date: Sun, 8 Jan 2023 18:20:22 +0000
Subject: [PATCH] Update multiple channel support

---
 README.md                             | 10 ++++++++++
 multi-nixpkgs/flake.lock              | 19 ++++++++++++++++++-
 multi-nixpkgs/flake.nix               |  3 ++-
 multi-nixpkgs/home-manager/home.nix   |  1 +
 multi-nixpkgs/nixos/configuration.nix |  1 +
 multi-nixpkgs/overlays/default.nix    |  6 ++++++
 6 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 9c8537f..40c4a1a 100644
--- a/README.md
+++ b/README.md
@@ -105,6 +105,16 @@ the latest and greatest nix3 flake-enabled command UX.
 
 # What next?
 
+## Multiple nixpkgs channels
+
+`multi-nixpkgs` shows how to setup multiple nixpkgs channels. For example, using the stable channel you can add the unstable version of neovim like:
+
+```
+home.packages = with pkgs; [
+  unstable.neovim
+];
+```
+
 ## Adding more hosts or users
 
 You can organize them by hostname and username on `nixos` and `home-manager`
diff --git a/multi-nixpkgs/flake.lock b/multi-nixpkgs/flake.lock
index 6b8c59c..220e02c 100644
--- a/multi-nixpkgs/flake.lock
+++ b/multi-nixpkgs/flake.lock
@@ -37,10 +37,27 @@
         "type": "github"
       }
     },
+    "nixpkgs-unstable": {
+      "locked": {
+        "lastModified": 1672953546,
+        "narHash": "sha256-oz757DnJ1ITvwyTovuwG3l9cX6j9j6/DH9eH+cXFJmc=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "a518c77148585023ff56022f09c4b2c418a51ef5",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "root": {
       "inputs": {
         "home-manager": "home-manager",
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "nixpkgs-unstable": "nixpkgs-unstable"
       }
     },
     "utils": {
diff --git a/multi-nixpkgs/flake.nix b/multi-nixpkgs/flake.nix
index b19bf5f..a7d0764 100644
--- a/multi-nixpkgs/flake.nix
+++ b/multi-nixpkgs/flake.nix
@@ -4,6 +4,7 @@
   inputs = {
     # Nixpkgs
     nixpkgs.url = "github:nixos/nixpkgs/nixos-22.11";
+    nixpkgs-unstable.url = "github:nixos/nixpkgs/nixos-unstable";
 
     # Home manager
     home-manager.url = "github:nix-community/home-manager";
@@ -43,7 +44,7 @@
       );
 
       # Your custom packages and modifications, exported as overlays
-      overlays = import ./overlays;
+      overlays = import ./overlays { inherit inputs; };
       # Reusable nixos modules you might want to export
       # These are usually stuff you would upstream into nixpkgs
       nixosModules = import ./modules/nixos;
diff --git a/multi-nixpkgs/home-manager/home.nix b/multi-nixpkgs/home-manager/home.nix
index 9256458..53ba612 100644
--- a/multi-nixpkgs/home-manager/home.nix
+++ b/multi-nixpkgs/home-manager/home.nix
@@ -18,6 +18,7 @@
     # You can add overlays here
     overlays = [
       # Add overlays your own flake exports (from overlays and pkgs dir):
+      outputs.overlays.unstable
       outputs.overlays.modifications
       outputs.overlays.additions
 
diff --git a/multi-nixpkgs/nixos/configuration.nix b/multi-nixpkgs/nixos/configuration.nix
index 3745e4c..98ea9fb 100644
--- a/multi-nixpkgs/nixos/configuration.nix
+++ b/multi-nixpkgs/nixos/configuration.nix
@@ -22,6 +22,7 @@
     # You can add overlays here
     overlays = [
       # Add overlays your own flake exports (from overlays and pkgs dir):
+      outputs.overlays.unstable
       outputs.overlays.modifications
       outputs.overlays.additions
 
diff --git a/multi-nixpkgs/overlays/default.nix b/multi-nixpkgs/overlays/default.nix
index b2653c9..b068a55 100644
--- a/multi-nixpkgs/overlays/default.nix
+++ b/multi-nixpkgs/overlays/default.nix
@@ -1,5 +1,11 @@
+{ inputs, ... }:
 # This file defines overlays
 {
+  # Sets `unstable` under `pkgs` as the nixpkgs unstable channel
+  unstable = final: _prev: {
+    unstable = inputs.nixpkgs-unstable.legacyPackages.${final.system};
+  };
+
   # This one brings our custom packages from the 'pkgs' directory
   additions = final: _prev: import ../pkgs { pkgs = final; };