Odoo 8 @api.onchange function not let update/Created one2many value
<p>I am building a module (Odoo 8) , my target is create offers in sale order, this offer can set a fix price for a determinate product or set a gift to zero cost. </p>

<p>I am adding my custom model offer_line, in new tab inside sale order. </p>

<p>Is defined like this:</p>

<pre><code>class OfferSaleOrderLine(models.Model):

_name = 'offer.sale.order.line'

sale_order_ref = fields.Many2one('sale.order',ondelete='set null', string="Sale Order", index=True)

offer_ref = fields.Many2one('offer',ondelete='set null', string="Oferta", index=True)

is_active = fields.Boolean(default=True,string='Activo')

accumulations = fields.Float(digits=(6, 2), help="Acumulaciones")

 class SaleOrder(models.Model):

_inherit = 'sale.order'

offers_lines = fields.One2many('offer.sale.order.line','sale_order_ref', string="Lineas de Ofertas")
</code></pre>

<p>I have a new api onchange method inside sale order:</p>

<pre><code> @api.onchange('offers_lines')

def _onchange_offers_lines(self):
</code></pre>

<p>I check is offer need apply, and i add to offers_line new lines from this onchange function, like this:</p>

<pre><code>self.offers_lines += self.env['offer.sale.order.line'].new({'is_active': True, 'offer_ref': offer, 'accumulations' : is_offer})
</code></pre>

<p>This is working perfect, lines is created, added to tab in form and onchange methods is trigger. </p>

<p>But the problem is next, if i try the same with sale order line, no working:</p>

<pre><code>     val = {

'name': gift_line.free_product.name,

'order_id': self.id,

'product_id': gift_line.free_product.id,

'product_uom_qty': gift_line.qty,

'product_uom': self.order_line[0].product_uom.id,

'price_unit': 0.0,

'state': 'draft',

}

self.order_line += self.env['sale.order.line'].new(val)
</code></pre>

<p>In log, this lines is created, i can see the newid id is created when i foreach self.order_line </p>

<p>****ORDER LINES : ID :  ; Product: product.product(5152,) ; Qty: 6.0 ; Price: 0.0 ;****</p>

<p>but the item is no created in sale order line tab, i dont know why, my custom lines(One2many) is created, but, the sale_order_lines, with same code and one2many field too, is not created. I have the same problem if i try set the price_unit to this sale_order_lines. Log says changes is added, but is not updated in form. In next onchange trigger, the changes is dissapear.</p>

<p>Thanks to all!</p>