Create a new method on statement lines to get the currency

account_statement_operation_rule/model/__init__.py

@@ -1,3 +1,4 @@
 # -*- coding: utf-8 -*-
 
 from . import account_statement_operation_rule
+from . import account_statement_line

account_statement_operation_rule/model/account_statement_line.py

@@ -0,0 +1,31 @@
+# -*- coding: utf-8 -*-
+##############################################################################
+#
+#    Author: Guewen Baconnier
+#    Copyright 2014 Camptocamp SA
+#
+#    This program is free software: you can redistribute it and/or modify
+#    it under the terms of the GNU Affero General Public License as
+#    published by the Free Software Foundation, either version 3 of the
+#    License, or (at your option) any later version.
+#
+#    This program is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU Affero General Public License for more details.
+#
+#    You should have received a copy of the GNU Affero General Public License
+#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+##############################################################################
+
+
+from openerp import models, api
+
+
+class AccountBankStatementLine(models.Model):
+    _inherit = 'account.bank.statement.line'
+
+    @api.multi
+    def currency_for_rules(self):
+        return self.currency_id or self.statement_id.currency

account_statement_operation_rule/model/account_statement_operation_rule.py

@@ -75,8 +75,7 @@ class AccountStatementOperationRule(models.Model):
 
     @api.model
     def _is_multicurrency(self, statement_line):
-        currency = (statement_line.currency_id or
+        currency = statement_line.currency_for_rules()
-                    statement_line.statement_id.currency)
         company_currency = statement_line.company_id.currency_id
         return currency != company_currency
 
@@ -84,8 +83,7 @@ class AccountStatementOperationRule(models.Model):
     def _is_valid_balance(self, statement_line, move_lines, balance):
         if self._is_multicurrency(statement_line):
             return False
-        currency = (statement_line.currency_id or
+        currency = statement_line.currency_for_rules()
-                    statement_line.statement_id.currency)
         return self._balance_in_range(balance, currency)
 
     @api.multi
@@ -93,8 +91,7 @@ class AccountStatementOperationRule(models.Model):
         # FIXME: surely wrong
         if self._is_multicurrency(statement_line):
             return False
-        currency = (statement_line.currency_id or
+        currency = statement_line.currency_for_rules()
-                    statement_line.statement_id.currency)
         amount_currency = statement_line.amount_currency
         for move_line in move_lines:
             if move_line.currency_id != statement_line.currency_id:
@@ -145,8 +142,7 @@ class AccountStatementOperationRule(models.Model):
         for move_line in move_lines:
             balance += move_line.credit - move_line.debit
 
-        currency = (statement_line.currency_id or
+        currency = statement_line.currency_for_rules()
-                    statement_line.statement_id.currency)
         if currency.is_zero(balance):
             return self.browse()