From 9f0507cf7d62472650bb3f2d936d0d43ef6009b4 Mon Sep 17 00:00:00 2001
From: Daiderd Jordan <daiderd@gmail.com>
Date: Wed, 6 Sep 2017 23:55:14 +0200
Subject: [PATCH] activation-checks: add check for user channels

---
 modules/system/activation-checks.nix | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/modules/system/activation-checks.nix b/modules/system/activation-checks.nix
index 7c885d8a..9dac0040 100644
--- a/modules/system/activation-checks.nix
+++ b/modules/system/activation-checks.nix
@@ -34,6 +34,25 @@ let
     fi
   '';
 
+  nixChannels = ''
+    channelsLink=$(readlink "$HOME/.nix-defexpr/channels") || true
+    case "$channelsLink" in
+      *"$USER"*)
+        ;;
+      "")
+        ;;
+      *)
+        echo "error: The ~/.nix-defexpr/channels symlink does not point your users channels" >&2
+        echo "Running nix-channel will regenerate it" >&2
+        echo >&2
+        echo "    rm ~/.nix-defexpr/channels" >&2
+        echo "    nix-channel --update" >&2
+        echo >&2
+        exit 2
+        ;;
+    esac
+  '';
+
   nixPath = ''
     darwinConfig=$(NIX_PATH=${concatStringsSep ":" config.nix.nixPath} nix-instantiate --eval -E '<darwin-config>') || true
     if ! test -e "$darwinConfig"; then
@@ -84,6 +103,7 @@ in
     system.activationScripts.checks.text = ''
       ${darwinChanges}
       ${buildUsers}
+      ${nixChannels}
       ${nixPath}
 
       if test ''${checkActivation:-0} -eq 1; then