[IMP] sale_triple_discount: Improves perfs and consistency

When computing the amount total on a sale.order.line, we now avoid to play with the cache since this change introduced in e3e59ba introduces a decline in performance. When the cache in invalidated, fields are flushed to the database and depending computed fields are recomputed..... This ultimately leads to temporary inconsistencies breaking others addons relaying on this one. Moreover, the method used in this original commit 'self.invalidate_cache(fnames=self._discount_fields(), ids=self.ids)' is deprecated and the use of the recommended new one lead to others side effects. The original approach is replaced by a contextual method modifying only the discount field when we need it's needed to don't break code relaying on the fact that the discount field is the total discount to apply to a line. This contextual method ensures that the original value is properly restored on exit and that it will not trigger additional recompute due to the temporary change of the discount value

sale_triple_discount/models/sale_order_line.py

@@ -4,6 +4,8 @@
 # Copyright 2018 Simone Rubino - Agile Business Group
 # License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
 
+from contextlib import contextmanager
+
 from odoo import _, api, fields, models
 from odoo.exceptions import ValidationError
 
@@ -66,9 +68,8 @@ def _discount_fields(self):
 
  @api.depends("discount2", "discount3", "discounting_type")
  def _compute_amount(self):
- prev_values = self.triple_discount_preprocess()
- res = super()._compute_amount()
- self.triple_discount_postprocess(prev_values)
+ with self._aggregated_discount() as lines:
+ res = super(SaleOrderLine, lines)._compute_amount()
  return res
 
  _sql_constraints = [
@@ -93,37 +94,40 @@ def _prepare_invoice_line(self, **kwargs):
  res.update({"discount2": self.discount2, "discount3": self.discount3})
  return res
 
- def triple_discount_preprocess(self):
- """Prepare data for post processing.
-
- Save the values of the discounts in a dictionary,
- to be restored in postprocess.
- Resetting every discount except the main one to 0.0 avoids issues if
- this method is called multiple times.
- Updating the cache provides consistency through re-computations."""
- prev_values = dict()
- self.invalidate_recordset(self._discount_fields())
- for line in self:
- prev_values[line] = {
- fname: line[fname] for fname in self._discount_fields()
- }
-
- vals = {fname: 0 for fname in self._discount_fields()}
- vals["discount"] = line._get_final_discount()
-
- line._cache.update(vals)
- return prev_values
-
- @api.model
- def triple_discount_postprocess(self, prev_values):
- """Restore the discounts of the lines in the dictionary prev_values.
- Updating the cache provides consistency through re-computations."""
- self.invalidate_recordset(self._discount_fields())
- for line, prev_vals_dict in list(prev_values.items()):
- line.update(prev_vals_dict)
+ @contextmanager
+ def _aggregated_discount(self):
+ """A context manager to temporarily change the discount value on the
+ records and restore it after the context is exited. It temporarily
+ changes the discount value to the aggregated discount value so that
+ methods that depend on the discount value will use the aggregated
+ discount value instead of the original one.
+ """
+ discount_field = self._fields["discount"]
+ # Protect discount field from triggering recompute of totals. We don't want
+ # to invalidate the cache to avoid to flush the records to the database.
+ # This is safe because we are going to restore the original value at the end
+ # of the method.
+ with self.env.protecting([discount_field], self):
+ old_values = {}
+ for line in self:
+ old_values[line.id] = line.discount
+ aggregated_discount = line._get_final_discount()
+ line.update({"discount": aggregated_discount})
+ yield self.with_context(discount_is_aggregated=True)
+ for line in self:
+ if line.id not in old_values:
+ continue
+ line.with_context(
+ restoring_triple_discount=True,
+ ).update({"discount": old_values[line.id]})
 
  def _convert_to_tax_base_line_dict(self):
  self.ensure_one()
+ discount = (
+ self.discount
+ if self.env.context.get("discount_is_aggregated")
+ else self._get_final_discount()
+ )
  return self.env["account.tax"]._convert_to_tax_base_line_dict(
  self,
  partner=self.order_id.partner_id,
@@ -132,6 +136,6 @@ def _convert_to_tax_base_line_dict(self):
  taxes=self.tax_id,
  price_unit=self.price_unit,
  quantity=self.product_uom_qty,
- discount=self._get_final_discount(),
+ discount=discount,
  price_subtotal=self.price_subtotal,
  )