--- a/util/startup.lua	Wed Mar 20 12:45:58 2019 +0000
+++ b/util/startup.lua	Wed Mar 20 13:44:29 2019 +0000
@@ -101,8 +101,10 @@
 
 function startup.log_startup_warnings()
 	dependencies.log_warnings();
-	for _, warning in ipairs(config_warnings) do
-		log("warn", "Configuration warning: %s", warning);
+	if config_warnings then
+		for _, warning in ipairs(config_warnings) do
+			log("warn", "Configuration warning: %s", warning);
+		end
 	end
 end