Models that uses _inherits will search in inherited parents for missing functions

This will prevent the needs to define on_change_* function and button method
in the child Model. In case of diamond problem, it is the first parent in the
dictionary that will be taken.

CHANGELOG

@@ -1,3 +1,4 @@
+* Models that uses _inherits will search in inherited parents for missing functions
 * Remove ids from on_change* calls
 * Improve search on translatable fields
 * export_data return empty value for invisible fields

trytond/model/model.py

@@ -113,6 +113,35 @@ class Model(object):
                 if on_change_with not in self._rpc:
                     self._rpc[on_change_with] = False
 
+    def __getattr__(self, name):
+        try:
+            super(Model, self).__getattr__(name)
+        except AttributeError:
+            # Search if a function exists in inherits parents
+            for model_name, field_name in self._inherits.iteritems():
+                model_obj = self.pool.get(model_name)
+                if hasattr(model_obj, name) and \
+                        callable(getattr(model_obj, name)):
+                    def func(cursor, user, *args, **kwargs):
+                        if args:
+                            ids = args[0]
+                            int_id = False
+                            if isinstance(ids, (int, long)):
+                                int_id = True
+                                ids = [ids]
+                            if reduce(lambda x, y: x and
+                                    isinstance(y, (int, long)), ids, True):
+                                # Replace ids by the parent ids
+                                ids = [getattr(x, field_name).id for x in
+                                        self.browse(cursor, user, ids)]
+                            if int_id:
+                                ids = ids[0]
+                            args = tuple([ids] + list(args[1:]))
+                        return getattr(model_obj, name)(cursor, user, *args,
+                                **kwargs)
+                    return func
+            raise
+
     def _inherits_reload(self):
         """
         Reconstruct _inherit_fields