[FIX] account: fix fiscal position with delivery address

The goal is to ensure that 2 conditions are met for a fiscal position to
be applied (within the EU):

- The customer must have a valid VAT number from another EU Member State
- The goods must leave the country of origin

closes odoo/odoo#81832

Task: 2596204
Forward-port-of: odoo/odoo#75033
Signed-off-by: Quentin De Paoli <qdp@odoo.com>
Signed-off-by: William André (wan) <wan@odoo.com>

addons/account/models/partner.py

@@ -215,8 +215,15 @@ class AccountFiscalPosition(models.Model):
         if not partner:
             return self.env['account.fiscal.position']
 
-        # if no delivery use invoicing
-        if not delivery:
+        company = self.env.company
+        intra_eu = vat_exclusion = False
+        if company.vat and partner.vat:
+            eu_country_codes = set(self.env.ref('base.europe').country_ids.mapped('code'))
+            intra_eu = company.vat[:2] in eu_country_codes and partner.vat[:2] in eu_country_codes
+            vat_exclusion = company.vat[:2] == partner.vat[:2]
+
+        # If company and partner have the same vat prefix (and are both within the EU), use invoicing
+        if not delivery or (intra_eu and vat_exclusion):
             delivery = partner
 
         # partner manually set fiscal position always win

addons/sale_stock/tests/test_create_perf.py

@@ -38,7 +38,7 @@ class TestPERF(common.TransactionCase):
     @users('admin')
     @warmup
     def test_empty_sale_order_creation_perf(self):
-        with self.assertQueryCount(admin=33):
+        with self.assertQueryCount(admin=34):
             self.env['sale.order'].create({
                 'partner_id': self.partners[0].id,
                 'user_id': self.salesmans[0].id,
@@ -87,7 +87,7 @@ class TestPERF(common.TransactionCase):
     @users('admin')
     @warmup
     def test_light_sales_orders_batch_creation_perf(self):
-        with self.assertQueryCount(admin=68):  # 67 locally, 68 in nightly runbot
+        with self.assertQueryCount(admin=69):  # 68 locally, 69 in nightly runbot
             self.env['sale.order'].create([{
                 'partner_id': self.partners[0].id,
                 'user_id': self.salesmans[0].id,