[FIX] purchase_stock: Prevent picking update when product_qty isn't updated

_create_or_update_picking() is a time-consuming method.
On some Purchase, all the purchase.order.line may be written with 'product_qty' in 'values', even though it did not change.

OPW-2978569

closes odoo/odoo#117296

X-original-commit: 0a5aa603
Signed-off-by: William Henrotin (whe) <whe@odoo.com>
Signed-off-by: David <dafr@odoo.com>

addons/purchase_stock/models/purchase.py

@@ -350,7 +350,8 @@ class PurchaseOrderLine(models.Model):
                 lambda m: m.state not in ['cancel', 'done']
             ).product_packaging_id = values['product_packaging_id']
 
-        previous_product_qty = {line.id: line.product_uom_qty for line in lines}
+        previous_product_uom_qty = {line.id: line.product_uom_qty for line in lines}
+        previous_product_qty = {line.id: line.product_qty for line in lines}
         result = super(PurchaseOrderLine, self).write(values)
         if 'price_unit' in values:
             for line in lines:
@@ -358,7 +359,8 @@ class PurchaseOrderLine(models.Model):
                 moves = line.move_ids.filtered(lambda s: s.state not in ('cancel', 'done') and s.product_id == line.product_id)
                 moves.write({'price_unit': line._get_stock_move_price_unit()})
         if 'product_qty' in values:
-            lines.with_context(previous_product_qty=previous_product_qty)._create_or_update_picking()
+            lines = lines.filtered(lambda l: float_compare(previous_product_qty[l.id], l.product_qty, precision_rounding=l.product_uom.rounding) != 0)
+            lines.with_context(previous_product_qty=previous_product_uom_qty)._create_or_update_picking()
         return result
 
     def action_product_forecast_report(self):