[FIX] sale_coupon: Do not validate generated coupons on SO cancellation

models/sale_coupon.py

@@ -36,6 +36,8 @@ class SaleCoupon(models.Model):
     program_id = fields.Many2one('sale.coupon.program', "Program")
     order_id = fields.Many2one('sale.order', 'Order Reference', readonly=True,
         help="The sales order from which coupon is generated")
+    sales_order_id = fields.Many2one('sale.order', 'Applied on order', readonly=True,
+        help="The sales order on which the coupon is applied")
     discount_line_product_id = fields.Many2one('product.product', related='program_id.discount_line_product_id',
         help='Product used in the sales order to apply the discount.')
 

models/sale_order.py

@@ -7,7 +7,7 @@ from odoo import api, fields, models
 class SaleOrder(models.Model):
     _inherit = "sale.order"
 
-    applied_coupon_ids = fields.One2many('sale.coupon', 'order_id', string="Applied Coupons", copy=False)
+    applied_coupon_ids = fields.One2many('sale.coupon', 'sales_order_id', string="Applied Coupons", copy=False)
     generated_coupon_ids = fields.One2many('sale.coupon', 'order_id', string="Offered Coupons", copy=False)
     reward_amount = fields.Float(compute='_compute_reward_total')
     no_code_promo_program_ids = fields.Many2many('sale.coupon.program', string="Applied Immediate Promo Programs",