From cd7c8561713c98fc0e618dcc8098eb33c594f9ef Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?C=C3=A9dric=20Krier?= <ced@b2ck.com>
Date: Wed, 25 Jul 2018 21:56:39 +0200
Subject: [PATCH] Prevent negative price as result of promotion

issue7571
review62311002
---
 sale.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sale.py b/sale.py
index a5b542cd1a..29c26430a7 100644
--- a/sale.py
+++ b/sale.py
@@ -282,7 +282,7 @@ class SalePromotion(
     def get_unit_price(self, **context):
         'Return unit price (as Decimal)'
         context.setdefault('functions', {})['Decimal'] = Decimal
-        return simple_eval(decistmt(self.formula), **context)
+        return max(simple_eval(decistmt(self.formula), **context), Decimal(0))
 
 
 class SalePromotion_Product(ModelSQL):