OpenERP - Show child_ids invoices of a partner - openerp-7

Question

I'd like to show invoices adressed to child partner in the parent partner form view.
I've already a inherited res_partner model as follow :
class res_partner(osv.osv):
_inherit = 'res.partner'
_columns = {
'invoice_ids': fields.one2many('account.invoice', 'partner_id', 'Invoices'),
}
And a view displaying invoices as follow :
<?xml version="1.0"?>
<openerp>
<data>
<!-- Partners inherited form -->
<record id="view_history_partner_info_form" model="ir.ui.view">
<field name="name">res.partner.cap_history.form.inherit</field>
<field name="inherit_id" ref="base.view_partner_form"/>
<field name="model">res.partner</field>
<field name="arch" type="xml">
<page string="Accounting" position="after" version="7.0">
<page string="History" name="cap_history_tab">
<group name="grp_invoice_history" string="Invoices History">
<field name="invoice_ids" colspan="4" nolabel="1">
<tree string="Partner Invoices" create="false" delete="false">
<field name="number" readonly="True"/>
<field name="origin" readonly="True"/>
<field name="name" string="Reference" readonly="True"/>
<field name="date_invoice" readonly="True"/>
<field name="x_category" readonly="True"/>
<field name="state" readonly="True"/>
<field name="payment_term" readonly="True"/>
<field name="amount_total" readonly="True"/>
</tree>
</field>
</group>
</page>
</page>
</field>
</record>
With this code I can see invoices that are directly adressed to a company or a person on their respective form view.
But if an invoice is adressed to person, and none is adressed to the parent company, when I am on the company form view, I won't see the invoice adressed to the child contact.
Is there a way to make visible the contact's invoice in the parent partner form view ?
Thank you for your help !
Cheers

Answer 1

One way to do this is to add a new field, all_invoice_ids, as a function field, and then have the function return both the contents of invoice_ids, plus the contents of any child's invoice_ids.
Something like this (untested):
'all_invoice_ids': fields.function(
_get_invoice_ids,
type='one2many',
obj='account.invoice',
method=True,
string='Invoices',
),
and _get_invoice_ids (which should be defined before columns) like this (also untested):
def _get_invoice_ids(self, cr, uid, ids, field_name, arg, context=None):
res = {}
if isinstance(ids, (int, long)):
ids = [ids] # in case an id was passed in directly
for main_partner in self.browse(cr, uid, ids, context=context):
main_invoices = main_partner.invoice_ids or [] # in case it was False
invoices = [inv.id for inv in main_invoices]
for child_partner in main_partner.child_ids:
child_invoices = child_partner.invoice_ids or []
invoices.extend([inv.id for inv in child_invoices])
# at this point we should have all the invoice ids
# use a set to get rid of duplicates
invoices = list(set(invoices))
# and store in res to be returned
res[main_partner.id] = invoices
return res