[IMP] purchase: default account journal

When the user clicks on the stat button "Invoices", then creates a new
invoice, the default currency of the new invoice will be based on the
default account journal. If the default account journal is not in the
currency of the PO, this will lead to an invoice which is not in the
same currency than the PO. This is not a bug in itself, but most of the
time, the user will want to create an invoice in the same currency than
the PO.

If no invoice is linked to the PO, the fix sets a default account
journal in the currency of the PO, as long as one can be found. If an
invoice is already linked to the PO, it uses the same account journal.

opw-667743

addons/purchase/purchase.py

@@ -398,15 +398,28 @@ class PurchaseOrder(models.Model):
 
         #override the context to get rid of the default filtering
         result['context'] = {'type': 'in_invoice', 'default_purchase_id': self.id}
-        result['domain'] = "[('purchase_id', '=', %s)]" % self.id
-        invoice_ids = sum([order.invoice_ids.ids for order in self], [])
+
+        if not self.invoice_ids:
+            # Choose a default account journal in the same currency in case a new invoice is created
+            journal_domain = [
+                ('type', '=', 'purchase'),
+                ('company_id', '=', self.company_id.id),
+                ('currency_id', '=', self.currency_id.id),
+            ]
+            default_journal_id = self.env['account.journal'].search(journal_domain, limit=1)
+            if default_journal_id:
+                result['context']['default_journal_id'] = default_journal_id.id
+        else:
+            # Use the same account journal than a previous invoice
+            result['context']['default_journal_id'] = self.invoice_ids[0].journal_id.id
+
         #choose the view_mode accordingly
-        if len(invoice_ids) > 1:
-            result['domain'] = "[('id','in',[" + ','.join(map(str, invoice_ids)) + "])]"
-        elif len(invoice_ids) == 1:
+        if len(self.invoice_ids) != 1:
+            result['domain'] = "[('id', 'in', " + str(self.invoice_ids.ids) + ")]"
+        elif len(self.invoice_ids) == 1:
             res = self.env.ref('account.invoice_supplier_form', False)
             result['views'] = [(res and res.id or False, 'form')]
-            result['res_id'] = invoice_ids and invoice_ids[0] or False
+            result['res_id'] = self.invoice_ids.id
         return result