[FIX] pos,repair,sale(_*): multi-company taxes management

Since product can be shared between multiple companies, their taxes m2m
fields may hold taxes from multiple companies.  When working in sudoed
or multi-company environments, those taxes were incorrectly filtered and
taxes from other companies may erroneously impact records from other
companies.

This commit ensures that the product taxes are properly filtered to only
consider the ones from the current/record company.

addons/point_of_sale/models/pos_order.py

@@ -846,8 +846,8 @@ class PosOrderLine(models.Model):
                 raise UserError(_('You have to select a pricelist in the sale form.'))
             price = self.price_unit * (1 - (self.discount or 0.0) / 100.0)
             self.price_subtotal = self.price_subtotal_incl = price * self.qty
-            if (self.product_id.taxes_id):
-                taxes = self.product_id.taxes_id.compute_all(price, self.order_id.pricelist_id.currency_id, self.qty, product=self.product_id, partner=False)
+            if (self.tax_ids):
+                taxes = self.tax_ids.compute_all(price, self.order_id.pricelist_id.currency_id, self.qty, product=self.product_id, partner=False)
                 self.price_subtotal = taxes['total_excluded']
                 self.price_subtotal_incl = taxes['total_included']
 

addons/sale_coupon/models/sale_order.py

@@ -140,9 +140,8 @@ class SaleOrder(models.Model):
 
     def _get_reward_values_discount(self, program):
         if program.discount_type == 'fixed_amount':
-            taxes = program.discount_line_product_id.taxes_id
-            if self.fiscal_position_id:
-                taxes = self.fiscal_position_id.map_tax(taxes)
+            product_taxes = program.discount_line_product_id.taxes_id.filtered(lambda tax: tax.company_id == self.company_id)
+            taxes = self.fiscal_position_id.map_tax(product_taxes)
             return [{
                 'name': _("Discount: %s", program.name),
                 'product_id': program.discount_line_product_id.id,

addons/sale_purchase/models/sale_order.py

@@ -230,9 +230,8 @@ class SaleOrderLine(models.Model):
             uom_id=self.product_id.uom_po_id
         )
         fpos = purchase_order.fiscal_position_id
-        taxes = fpos.map_tax(self.product_id.supplier_taxes_id)
-        if taxes:
-            taxes = taxes.filtered(lambda t: t.company_id.id == self.company_id.id)
+        supplier_taxes = self.product_id.supplier_taxes_id.filtered(lambda t: t.company_id.id == self.company_id.id)
+        taxes = fpos.map_tax(supplier_taxes)
 
         # compute unit price
         price_unit = 0.0