nix: kickstart and wait for the nix-daemon service

.travis.yml

@@ -8,9 +8,7 @@ matrix:
       - nix-build ./release.nix -I darwin=. -A tests
       - nix-build ./release.nix -I darwin=. -A examples.simple
       - yes | nix-shell -A installer
-      - sudo launchctl kickstart system/org.nixos.nix-daemon  # FIXME
       - nix-shell -A installer.check
       - /run/current-system/sw/bin/darwin-rebuild switch -I darwin=$HOME/.nix-defexpr/channels/darwin -I darwin-config=$HOME/.nixpkgs/darwin-configuration.nix
-      - sudo launchctl kickstart system/org.nixos.nix-daemon  # FIXME
       - yes | nix-shell -A uninstaller
       - nix-shell -A uninstaller.check

modules/nix/default.nix

@@ -444,9 +444,13 @@ in
 
     system.activationScripts.nix-daemon.text = mkIf cfg.useDaemon ''
       if ! diff /etc/nix/nix.conf /run/current-system/etc/nix/nix.conf &> /dev/null; then
-          echo >&2 "reloading nix-daemon..."
-          pkill -HUP nix-daemon
+          echo "reloading nix-daemon..." >&2
+          launchctl kill HUP system/org.nixos.nix-daemon
       fi
+      while ! nix-store --store daemon -q --hash ${pkgs.stdenv.shell} &>/dev/null; do
+          echo "waiting for nix-daemon" >&2
+          launchctl kickstart system/org.nixos.nix-daemon
+      done
     '';
 
   };

tests/services-nix-daemon.nix

@@ -25,7 +25,7 @@ in
     grep "<string>${cacert}/etc/ssl/certs/ca-certificates.crt</string>" ${config.out}/Library/LaunchDaemons/org.nixos.nix-daemon.plist
 
     echo checking nix-daemon reload in /activate >&2
-    grep "pkill -HUP nix-daemon" ${config.out}/activate
+    grep "launchctl kill HUP system/org.nixos.nix-daemon" ${config.out}/activate
 
     echo checking NIX_REMOTE=daemon in setEnvironment >&2
     grep "NIX_REMOTE=daemon" ${config.system.build.setEnvironment}