[FIX] account: ensure fiscal position belongs to the company of the invoice

When bank statements are imported using Enterprise's account_online_synchronization,
or when invoices are created from incoming email using mail aliases on
`account.journal`, journal entries can end up with a fiscal position from the default
company of the user that the `account.move` creation runs as, or the import fails
with an error "'Draft Entry' belongs to company X and 'Fiscal Position' belongs to
another company".

While account.move's `_compute_fiscal_company_id` calls `account.fiscal.position`'s
`_get_fiscal_position` with actual company of the move, it passes one or two
`res.partner` records to this method that were still browsed with the default company
of the executing user which could result in a fiscal position from that company,
instead of the company of the journal entry.

closes odoo/odoo#141059

X-original-commit: 71bd4f1378f56b333830cbc5aa11c1c55dcefcc3
Signed-off-by: William André (wan) <wan@odoo.com>
Co-authored-by: William Andre <wan@odoo.com>

addons/account/models/partner.py

@@ -237,7 +237,10 @@ class AccountFiscalPosition(models.Model):
             delivery = partner
 
         # partner manually set fiscal position always win
-        manual_fiscal_position = delivery.property_account_position_id or partner.property_account_position_id
+        manual_fiscal_position = (
+            delivery.with_company(company).property_account_position_id
+            or partner.with_company(company).property_account_position_id
+        )
         if manual_fiscal_position:
             return manual_fiscal_position
 

addons/account/tests/test_account_move_entry.py

@@ -134,6 +134,28 @@ class TestAccountMove(AccountTestInvoicingCommon):
 
         self.test_move.line_ids[0].account_id = custom_account
 
+    def test_fiscal_position_multicompany(self):
+        """A move is assigned a fiscal position that matches its own company."""
+        company1 = self.company_data["company"]
+        company2 = self.company_data_2["company"]
+        partner = self.env['res.partner'].create({'name': 'Belouga'})
+        fpos1 = self.env["account.fiscal.position"].create(
+            {
+                "name": company1.name,
+                "company_id": company1.id,
+            }
+        )
+        fpos2 = self.env["account.fiscal.position"].create(
+            {
+                "name": company2.name,
+                "company_id": company2.id,
+            }
+        )
+        partner.with_company(company1).property_account_position_id = fpos1
+        partner.with_company(company2).property_account_position_id = fpos2
+        self.test_move.sudo().with_company(company2).partner_id = partner
+        self.assertEqual(self.test_move.fiscal_position_id, fpos1)
+
     def test_misc_fiscalyear_lock_date_1(self):
         self.test_move.action_post()