[FIX] sale_margin: purchase_price performance.

When installing sale_margin, the computed fields will be computed on existing
sale.order and sale.order.line in database.  On huge databases, the computation
may take a lot of time, depending on the configuration (multi-company, multi-currency, ...)

The current commit improves the computation of the purchase_price
(recently changed to a computed field), by avoiding unnecessary currency
conversions when possible (one less query to get the conversion rates).

In a multi-currency database where the products have no cost defined
(standard_price field), the sale_margin installation takes up to 50% less time.

closes odoo/odoo#52338

X-original-commit: 3c9841d1aa4fc5b10012c8239a31d6e7f8676fc0
Signed-off-by: Victor Feyens (vfe) <vfe@odoo.com>

addons/sale_margin/models/sale_order.py

@@ -25,6 +25,12 @@ class SaleOrderLine(models.Model):
             line = line.with_company(line.company_id)
             product = line.product_id
             product_cost = product.standard_price
+            if not product_cost:
+                # If the standard_price is 0
+                # Avoid unnecessary computations
+                # and currency conversions
+                line.purchase_price = 0.0
+                continue
             fro_cur = product.cost_currency_id
             to_cur = line.currency_id or line.order_id.currency_id
             if line.product_uom and line.product_uom != product.uom_id:
@@ -38,7 +44,7 @@ class SaleOrderLine(models.Model):
                 company=line.company_id or self.env.company,
                 date=line.order_id.date_order or fields.Date.today(),
                 round=False,
-            ) if to_cur else product_cost
+            ) if to_cur and product_cost else product_cost
             # The pricelist may not have been set, therefore no conversion
             # is needed because we don't know the target currency..
 
@@ -46,7 +52,7 @@ class SaleOrderLine(models.Model):
     def _compute_margin(self):
         for line in self:
             line.margin = line.price_subtotal - (line.purchase_price * line.product_uom_qty)
-            line.margin_percent = line.price_subtotal  and line.margin/line.price_subtotal
+            line.margin_percent = line.price_subtotal and line.margin/line.price_subtotal
 
 
 class SaleOrder(models.Model):