From 9a04bc6f5e77c0919fbedc8216712dcfa269b8f5 Mon Sep 17 00:00:00 2001
From: Graham Christensen <graham@grahamc.com>
Date: Mon, 24 Jul 2017 22:37:22 -0400
Subject: [PATCH] Test to see if nix-daemon is running already

A user had an install, uninstalled it via the instructions, and found their nix broken.

The issue was based around nix-daemon already running.

I tried to be very smart around searching their launchctl files:

  $ grep -ri nix-daemon  ~/Library/LaunchAgents /Library/LaunchAgents /Library/LaunchDaemons /System/Library/LaunchAgents /System/Library/LaunchDaemons

but then couldn't figure out how to write out (nicely) commands for uninstalling
or unloading them based on their name, and also couching the instrunctions in a
bit of doubt so we don't piss off some poor mac admin because their users just
deleted some important launchd files.
---
 scripts/install-darwin-multi-user.sh | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/scripts/install-darwin-multi-user.sh b/scripts/install-darwin-multi-user.sh
index 57a85f46a..8ae1c9a20 100644
--- a/scripts/install-darwin-multi-user.sh
+++ b/scripts/install-darwin-multi-user.sh
@@ -296,6 +296,19 @@ EOF
 Nix already appears to be installed, and this tool assumes it is
 _not_ yet installed.
 
+$(uninstall_directions)
+EOF
+    fi
+
+    if pgrep nix-daemon 2> /dev/null >&2; then
+        failure <<EOF
+Nix seems to be partially installed, because the nix-daemon is
+currently running. It may be in a launchd service. Please stop the
+the old nix-daemon, and try again.
+
+If you have an existing launchd plist for nix-daemon, please delete
+it.
+
 $(uninstall_directions)
 EOF
     fi