From 8d05386958d82c45b50062268bb549a08051486f Mon Sep 17 00:00:00 2001
From: Moritz Bunkus <m.bunkus@linet-services.de>
Date: Thu, 18 Aug 2016 14:08:57 +0200
Subject: [PATCH] Payment-Helfer: Rechnen mit undefinierten Werten vermeiden

---
 SL/DB/Helper/Payment.pm | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/SL/DB/Helper/Payment.pm b/SL/DB/Helper/Payment.pm
index b7bf38a12..64d6a639c 100644
--- a/SL/DB/Helper/Payment.pm
+++ b/SL/DB/Helper/Payment.pm
@@ -387,7 +387,7 @@ sub open_amount {
   # if the difference is 0.01 Cent this may end up as 0.009999999999998
   # numerically, so round this value when checking for cent threshold >= 0.01
 
-  return $self->amount - $self->paid;
+  return ($self->amount // 0) - ($self->paid // 0);
 };
 
 sub open_percent {
-- 
2.20.1