From a5fe0dd36f79f13327b4ad2968c0ad803161120e Mon Sep 17 00:00:00 2001
From: jmartin <jmartin@zikzakmedia.com>
Date: Wed, 9 Jul 2014 10:52:33 +0200
Subject: [PATCH] Make pay button readonly if no lines are added to sale

---
 sale.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sale.py b/sale.py
index 564dc85..745b886 100644
--- a/sale.py
+++ b/sale.py
@@ -5,7 +5,7 @@ from decimal import Decimal
 
 from trytond.model import ModelView, fields
 from trytond.pool import PoolMeta, Pool
-from trytond.pyson import Eval
+from trytond.pyson import Bool, Eval, Not
 from trytond.transaction import Transaction
 from trytond.wizard import Wizard, StateView, StateTransition, Button
 
@@ -28,6 +28,7 @@ class Sale:
         cls._buttons.update({
                 'wizard_sale_payment': {
                     'invisible': Eval('state') == 'done',
+                    'readonly': Not(Bool(Eval('lines'))),
                     },
                 })