From d41367735d21c61f9260ef6037d8f4c6096baa80 Mon Sep 17 00:00:00 2001
From: Wout Mertens <Wout.Mertens@gmail.com>
Date: Sun, 15 Feb 2015 15:37:30 +0100
Subject: [PATCH] nix-daemon: Sanity check maxJobs vs nrBuildUsers

---
 nixos/modules/services/misc/nix-daemon.nix | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/nixos/modules/services/misc/nix-daemon.nix b/nixos/modules/services/misc/nix-daemon.nix
index e2548864af5b..9979c6c9815b 100644
--- a/nixos/modules/services/misc/nix-daemon.nix
+++ b/nixos/modules/services/misc/nix-daemon.nix
@@ -323,7 +323,12 @@ in
         fi
       '';
 
-    users.extraUsers = map makeNixBuildUser (range 1 cfg.nrBuildUsers);
+    users.extraUsers =
+      if cfg.nrBuildUsers >= cfg.maxJobs then
+        map makeNixBuildUser (range 1 cfg.nrBuildUsers)
+      else
+        throw "Not enough build users (${cfg.nrBuildUsers}) to support ${cfg.maxJobs} build jobs. Change nrBuildUsers or maxJobs."
+      ;
 
     system.activationScripts.nix = stringAfter [ "etc" "users" ]
       ''