Hi, I'm using Odoo 11, I would like to know if I'm doing the creation and manipulation of records on cache correctly.

This is a simplified version of my issue:

class model_A(model.Model):
    model_A_some_field = fields.Char()
    model_B_ids = fields.One2many('model_B', 'model_A_id')

class model_B(model.Model):
    model_A_id = fields.Many2one('model_A')
    model_B_some_field = fields.Char()

I need to create, during edition of the form of model_A, a model_B record. I achieved this using an onchange method and 'new' on the model_A class:

@api.onchange('model_A_some_field')
def _onchange_create_record(self):
    self.env['model_B'].new({
        model_A_id = self.id,
        model_B_some_field = 'text'
    })

The problem I'm having is that the model_B record gets created but the fields it has don't appear initialized. I randomly discovered that they get initialized only if they are present as columns on the list view of model_B_ids of the model_A form. Is this the only way to make the cache aware of the records created with new or am I missing something?