[ADD] base: list of inherited models on a ir.model

This field is needed to retrieve the list of inherited fields (instead of only the fields of a current model) of a model using domain such as ('model_id', 'in', model.inherited_model_ids) on ir.model.fields

openerp/addons/base/ir/ir_model.py

@@ -95,11 +95,21 @@ class ir_model(osv.osv):
             res[model.id] = self.pool["ir.ui.view"].search(cr, uid, [('model', '=', model.model)])
         return res
 
+    def _inherited_models(self, cr, uid, ids, field_name, arg, context=None):
+        res = dict.fromkeys(ids, [])
+        for model in self.browse(cr, uid, ids, context=context):
+            inherited_models = [model_name for model_name in self.pool[model.model]._inherits]
+            if inherited_models:
+                res[model.id] = self.search(cr, uid, [('model', 'in', inherited_models)], context=context)
+        return res
+
     _columns = {
         'name': fields.char('Model Description', translate=True, required=True),
         'model': fields.char('Model', required=True, select=1),
         'info': fields.text('Information'),
         'field_id': fields.one2many('ir.model.fields', 'model_id', 'Fields', required=True, copy=True),
+        'inherited_model_ids': fields.function(_inherited_models, type="many2many", obj="ir.model", string="Inherited models",
+            help="The list of models that extends the current model."),
         'state': fields.selection([('manual','Custom Object'),('base','Base Object')],'Type', readonly=True),
         'access_ids': fields.one2many('ir.model.access', 'model_id', 'Access'),
         'osv_memory': fields.function(_is_osv_memory, string='Transient Model', type='boolean',