If you are doing something in the onChange method in the one2Many field, eg, in the order_line in the sales.order, if you want to update additional info to the description ('name' field) upon adding of the product.
There will be a problem to get the parent ID. For example
a) You will not be able to get the id of the parent sale.order with self._origin.id.
b) Use the Context to pass the id of the parent.
<field name="myone2manyfields_ids" context="{'active_id': id}">
order = self.env['sales.order'].search([('id', '=', self.env.context.get('active_id'))], limit=1)
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