FIX l10n_it_withholding_tax in multi currency env. Use case: (OCA#451)

- Create a USD bank journal
 - Add 2 rates to USD currency: yesterday with rate 0.8; today with rate 0.9
 - Create an USD invoice with date = yesterday
 - Create a bank statement (on USD bank account) today registering a full payment and try to reconcile

Get "Valore di credito o debito errato nella registrazione contabile"

l10n_it_withholding_tax/__manifest__.py

@@ -4,11 +4,11 @@
 
 {
     'name': 'Italian Withholding Tax',
-    'version': '10.0.1.0.1',
+    'version': '10.0.1.0.2',
     'category': 'Account',
     'author': 'Openforce, Odoo Italia Network, '
               'Odoo Community Association (OCA)',
-    'website': 'https://odoo-community.org/',
+    'website': 'https://www.odoo-italia.net/',
     'license': 'AGPL-3',
     "depends": ['account'],
     "data": [

l10n_it_withholding_tax/models/account.py

@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
 # Copyright 2015 Alessandro Camilli (<http://www.openforce.it>)
+# Copyright 2018 Lorenzo Battistini - Agile Business Group
 # License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
 
 
@@ -29,7 +30,11 @@ def create(self, vals):
                 break
         # Limit value of reconciliation
         if invoice and invoice.amount_net_pay:
-            if vals.get('amount') > invoice.amount_net_pay:
+            # We must consider amount in foreign currency, if present
+            # Note that this is always executed, for every reconciliation.
+            # Thus, we must not chnage amount when not in withholding tax case
+            amount = vals.get('amount_currency') or vals.get('amount')
+            if amount > invoice.amount_net_pay:
                 vals.update({'amount': invoice.amount_net_pay})
 
         # Create reconciliation