old_contents: # -*- coding: utf-8 -*-
  ##############################################################################
  #
  #    OpenERP, Open Source Business Applications
  #    Copyright (c) 2013 S.A. <http://openerp.com>
  #
  #    This program is free software: you can redistribute it and/or modify
  #    it under the terms of the GNU Affero General Public License as
  #    published by the Free Software Foundation, either version 3 of the
  #    License, or (at your option) any later version.
  #
  #    This program is distributed in the hope that it will be useful,
  #    but WITHOUT ANY WARRANTY; without even the implied warranty of
  #    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  #    GNU Affero General Public License for more details.
  #
  #    You should have received a copy of the GNU Affero General Public License
  #    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  #
  ##############################################################################
  
  from openerp.osv import osv, fields
  
  class res_partner(osv.Model):
      _inherit = 'res.partner'
      _order = 'display_name'
  
      def _display_name_compute(self, cr, uid, ids, name, args, context=None):
          return dict(self.name_get(cr, uid, ids, context=context))
  
      _commercial_partner_id_store_triggers = {
          'res.partner': (lambda self,cr,uid,ids,context=None: self.search(cr, uid, [('id','child_of',ids)]),
                          ['parent_id', 'is_company'], 10)
      }
  
      # indirections to avoid passing a copy of the overridable method when declaring the function field
      _commercial_partner_id = lambda self, *args, **kwargs: self._commercial_partner_compute(*args, **kwargs)
      _display_name = lambda self, *args, **kwargs: self._display_name_compute(*args, **kwargs)
  
      _columns = {
          # make the original field stored, in case it's needed for reporting purposes
          'commercial_partner_id': fields.function(_commercial_partner_id, type='many2one', relation='res.partner', string='Commercial Entity',
                                                   store=_commercial_partner_id_store_triggers),
  
          # extra field to allow ORDER BY to match visible names
          'display_name': fields.function(_display_name, type='char', string='Name', store=_commercial_partner_id_store_triggers),
      }
  
  class account_invoice(osv.Model):
      _inherit = 'account.invoice'
  
      _columns = {
          'commercial_partner_id': fields.related('partner_id', 'commercial_partner_id', string='Commercial Entity', type='many2one',
                                                  relation='res.partner', store=True, readonly=True,
                                                  help="The commercial entity that will be used on Journal Entries for this invoice")
      }
  
new_contents: # -*- coding: utf-8 -*-
  ##############################################################################
  #
  #    OpenERP, Open Source Business Applications
  #    Copyright (c) 2013 S.A. <http://openerp.com>
  #
  #    This program is free software: you can redistribute it and/or modify
  #    it under the terms of the GNU Affero General Public License as
  #    published by the Free Software Foundation, either version 3 of the
  #    License, or (at your option) any later version.
  #
  #    This program is distributed in the hope that it will be useful,
  #    but WITHOUT ANY WARRANTY; without even the implied warranty of
  #    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  #    GNU Affero General Public License for more details.
  #
  #    You should have received a copy of the GNU Affero General Public License
  #    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  #
  ##############################################################################
  
  from openerp.osv import osv, fields
  
  class res_partner(osv.Model):
      _inherit = 'res.partner'
      _order = 'display_name'
  
      def _display_name_compute(self, cr, uid, ids, name, args, context=None):
          return dict(self.name_get(cr, uid, ids, context=context))
  
      _display_name_store_triggers = {
          'res.partner': (lambda self,cr,uid,ids,context=None: self.search(cr, uid, [('id','child_of',ids)]),
                          ['parent_id', 'is_company'], 10)
      }
  
      # indirection to avoid passing a copy of the overridable method when declaring the function field
      _display_name = lambda self, *args, **kwargs: self._display_name_compute(*args, **kwargs)
  
      _columns = {
          # extra field to allow ORDER BY to match visible names
          'display_name': fields.function(_display_name, type='char', string='Name', store=_display_name_store_triggers),
      }
  
  class account_invoice(osv.Model):
      _inherit = 'account.invoice'
  
      _columns = {
          'commercial_partner_id': fields.related('partner_id', 'commercial_partner_id', string='Commercial Entity', type='many2one',
                                                  relation='res.partner', store=True, readonly=True,
                                                  help="The commercial entity that will be used on Journal Entries for this invoice")
      }
  
subject: undo override of res.partner.commercial_partner_id field to store it, as the ORM does not support it and it's not strictly necessary