I try filter list of values in dropdown list of many2one field (this field is in tree). For this I've created functional field which return list of allowed ids. In xml file i used domain with in condition. Here's my code

In py file

class cm_order_line(osv.osv):
_name = 'cm.order.line'

def _get_order_ids(self, cr, uid, ids, field_names=None, arg=None, context=None):
task_order_ids = [5,9,10]    # only as simplification...
return task_order_ids

_columns = {
'order_id': fields.many2one('stock.picking', 'Order Name'),
'order_ids': fields.function(_get_order_ids, type='char', string='Orders IDs', store=False),

_defaults = {
'order_ids': _get_order_ids
}

In XML

<field name="order_ids" invisible="1"/>
<field name="order_id" on_change="onchange_order_id(order_id)" domain="[('type','=','out'),('id', 'in', order_ids)]"/>

Everything works fine when i create new record. Domain works normal but after save (or when i just want to open inserted records) it gives error

AttributeError: 'list' object has no attribute 'get'