[FIX] sale: sale order line quantity not rounded

Create a Field Service Task
Assing a customer, in Timesheet tab add a line with Hours Spent 00:20
Mark as Done
Sale Order will be created with a sale order line
Total of the line and Total of the order will not match

This occurs because the sale order line has been created with an
unrounded quantity of 0.333333

opw-3184468

closes odoo/odoo#118628

X-original-commit: ca72697042687e205fb288a97ec4717a97c89664
Related: odoo/enterprise#39799
Signed-off-by: Grazioso Andrea (agr) <agr@odoo.com>

addons/sale/models/sale_order_line.py

@@ -941,16 +941,16 @@ class SaleOrderLine(models.Model):
 
     #=== CRUD METHODS ===#
     def _add_precomputed_values(self, vals_list):
-        """ In the specific case where the discount is provided in the create values
+        """ In case an editable precomputed field is provided in the create values
         without being rounded, we have to 'manually' round it otherwise it won't be,
-        because editable precomputed field values are kept 'as is'.
+        because those field values are kept 'as is'.
 
         This is a temporary fix until the problem is fixed in the ORM.
         """
-        precision = self.env['decimal.precision'].precision_get('Discount')
         for vals in vals_list:
-            if vals.get('discount'):
-                vals['discount'] = float_round(vals['discount'], precision_digits=precision)
+            for fname in ('discount', 'product_uom_qty'):
+                if fname in vals:
+                    vals[fname] = self._fields[fname].convert_to_cache(vals[fname], self)
         return super()._add_precomputed_values(vals_list)
 
     @api.model_create_multi

addons/sale/tests/test_sale_prices.py

@@ -7,7 +7,7 @@ from datetime import timedelta
 from odoo import fields
 from odoo.fields import Command
 from odoo.tests import Form, tagged
-from odoo.tools import float_compare, mute_logger
+from odoo.tools import float_compare, mute_logger, float_round
 
 from odoo.addons.sale.tests.common import SaleCommon
 
@@ -978,3 +978,21 @@ class TestSalePrices(SaleCommon):
         # 136.36 price tax excluded with discount applied
         self.assertEqual(order.amount_undiscounted, 272.72)
         self.assertEqual(line.price_subtotal, 136.36)
+
+    def test_product_quantity_rounding(self):
+        """When adding a sale order line, product quantity should be rounded
+        according to decimal precision"""
+        order = self.empty_order
+
+        product_uom_qty = 0.333333
+        order.order_line = [Command.create({
+            'product_id': self.product.id,
+            'product_uom_qty': product_uom_qty,
+            'price_unit': 75.0,
+        })]
+        order.action_confirm()
+        line = order.order_line
+        quantity_precision = self.env['decimal.precision'].precision_get('Product Unit of Measure')
+        expected_price_subtotal = line.price_unit * float_round(product_uom_qty, precision_digits=quantity_precision)
+        self.assertAlmostEqual(line.price_subtotal, expected_price_subtotal)
+        self.assertEqual(order.amount_total, order.tax_totals.get('amount_total'))