odoo-event-addons/event_ticket_description_sale/models/event_event_ticket.py

from odoo import models, api


class EventEventTicket(models.Model):
    _inherit = "event.event.ticket"

    @api.depends("product_id")
    def _compute_description(self):
        for ticket in self:
            product = ticket.product_id
            description_sale = (
                product and product.get_product_multiline_description_sale() or False
            )
            if product and description_sale:
                ticket.description = description_sale
            if not ticket.description:
                ticket.description = False

    def _get_ticket_multiline_description(self):
        self.ensure_one()
        product = self.product_id
        description_sale = (
            product and product.get_product_multiline_description_sale() or False
        )
        if description_sale:
            return "%s\n%s" % (
                description_sale,
                self.event_id.display_name,
            )
        return super()._get_ticket_multiline_description()