odoo/odoo — pull request #1612 by rco-odoo (2014-08-06 07:50:08+00:00)
Title: [IMP] fields: add mechanism to extend a selection field

If a selection field is defined by a list as selection, such as:

state = fields.Selection([('a', 'A'), ('b', 'B')])

one can extend it by inheritance by redefining the field, as:

state = fields.Selection(selection_add=[('c', 'C')])

The result is that the selection field will have the list `[('a', 'A'), ('b', 'B'), ('c', 'C')]` as selection.