I have defined product_status in product.supplierinfo like this:

from odoo import fields, models
class ProductSupplierinfo(models.Model): 
  _inherit = 'product.supplierinfo'
	​product_status = fields.Selection(
		​​[('homologado','Homologado'),('no_homologado','No Homologado'),('on_hold','On Hold')], 
	​​	​string="Product Homologation Status",	​
		​​default=None,
		​​store=True)

In the user interface you can choose the value that you want it to be, then i want to show the value defined, when you do a PO.

For this I have added the field in the view purchase.order.line:

<odoo>    
	​<record id="view_purchase_order_form_inherit_custom" model="ir.ui.view">        
	​	​<field name="name">purchase.order.form.inherit.custom</field>        
	​	​<field name="model">purchase.order</field>        
	​	​<field name="inherit_id" ref="purchase.purchase_order_form"/>        
	​	​<field name="arch" type="xml">            
	​	​	​<!-- Agregar el campo product_status en la vista tree -->            
	​	​	​<xpath expr="//field[@name='order_line']/tree/field[@name='product_id']" position="after">                
	​	​	​	​<field name="product_status" string="Estado de Homologación"/>            	​	​	​</xpath>                        
	​	​	​<!-- Agregar el campo product_status en la vista form -->            
	​	​	​<xpath expr="//field[@name='order_line']/form/group/group/field[@name='product_id']" position="after">                
	​	​	​	​<field name="product_status" string="Estado de Homologación"/>          
	​	​	​</xpath>        	​
	​	​</field>    
	​</record>
</odoo>

Finally I have tried to relate both fields using the depends decorator, this is my code:

from odoo import models, fields, api

class PurchaseOrderLine(models.Model):    
	​_inherit = 'purchase.order.line'
 
	​product_status = fields.Selection(        
	​	​selection=[('homologado', 'Homologado'),('no_homologado', 'No Homologado'),('on_hold', 'On Hold')],        
	​	​string="Product Homologation Status",        
	​	​compute="_compute_product_status",        
	​	​store=True,        
	​	​readonly=True) 

	​@api.depends('product_id', 'partner_id')    
	​def _compute_product_status(self):        
	​	​for line in self:            
	​	​	​# Si no hay producto o partner, no hay nada que calcular           
	​	​	​if not line.product_id or not line.partner_id:
	​	​	​	​​line.product_status = False                
	​	​	​	​continue
	​	​	​# Busca el supplierinfo correspondiente            
	​	​	​supplierinfo = self.env['product.supplierinfo'].search([
	​	​	​	​('product_id', '=', line.product_id.id),
	​	​	​	​('partner_id', '=', line.partner_id.id),  
	​	​	​], limit=1)
	​	​	​# Si existe supplierinfo, toma el `product_status`            
	​	​	​if supplierinfo:                
	​	​	​	​line.product_status = supplierinfo.product_status            
	​	​	​else:                
	​	​	​	​line.product_status = "on_hold" 

My problem is that in the PO view it always appears the value of product_status as on_hold.

I dont know how to make both fields relate to each other, all help will be welcomed