[FIX] fix cannot change product company when only eixst single company

X-original-commit: 4364183ab51811362e01f0faddc7c273e315f7a8
Part-of: odoo/odoo#111683

addons/stock/models/product.py

@@ -843,7 +843,7 @@ class ProductTemplate(models.Model):
                 # Forbid changing a product's company when quant(s) exist in another company.
                 quant = self.env['stock.quant'].sudo().search([
                     ('product_id', 'in', products_changing_company.product_variant_ids.ids),
-                    ('company_id', '!=', vals['company_id']),
+                    ('company_id', 'not in', [vals['company_id'], False]),
                     ('quantity', '!=', 0),
                 ], order=None, limit=1)
                 if quant:

addons/stock/tests/test_product.py

@@ -130,6 +130,47 @@ class TestVirtualAvailable(TestStockCommon):
         self.env['stock.quant']._unlink_zero_quants()
         product.company_id = company2.id  # Should work this time.
 
+    def test_change_product_company_exclude_vendor_and_customer_location(self):
+        """ Checks we can change product company where only exist single company
+        and exist quant in vendor/customer location"""
+        company1 = self.env.ref('base.main_company')
+        customer_location = self.env.ref('stock.stock_location_customers')
+        supplier_location = self.env.ref('stock.stock_location_suppliers')
+        product = self.env['product.product'].create({
+            'name': 'Product Single Company',
+            'type': 'product',
+        })
+        # Creates a quant for company 1.
+        self.env['stock.quant'].create({
+            'product_id': product.id,
+            'product_uom_id': self.uom_unit.id,
+            'location_id': self.location_1.id,
+            'quantity': 5,
+        })
+        # Creates a quant for vendor location.
+        self.env['stock.quant'].create({
+            'product_id': product.id,
+            'product_uom_id': self.uom_unit.id,
+            'location_id': supplier_location.id,
+            'quantity': -15,
+        })
+        # Creates a quant for customer location.
+        self.env['stock.quant'].create({
+            'product_id': product.id,
+            'product_uom_id': self.uom_unit.id,
+            'location_id': customer_location.id,
+            'quantity': 10,
+        })
+        # Assigns a company: should be ok because only exist one company (exclude vendor and customer location)
+        product.company_id = company1.id
+
+        # Reset product company to empty
+        product.company_id = False
+        company2 = self.env['res.company'].create({'name': 'Second Company'})
+        # Assigns to another company: should be not okay because exist quants in defferent company (exclude vendor and customer location)
+        with self.assertRaises(UserError):
+            product.company_id = company2.id
+
     def test_search_qty_available(self):
         product = self.env['product.product'].create({
             'name': 'Brand new product',