Use dictionary as search_order on Reference field

issue11251
review387941002

CHANGELOG

@@ -1,3 +1,4 @@
+* Use dictionary as search_order on Reference field
 * Retry sending email on temporary failure
 * Order not sorted Selection by index definition
 * Add optional column on tree view

doc/ref/models/fields.rst

@@ -648,7 +648,9 @@ But a ``tuple`` can be used to search or set value.
 
 .. attribute:: Reference.search_order
 
-    Same as :attr:`Many2One.search_order`
+   A dictionary that contains a :ref:`PYSON <ref-pyson>` expression defining
+   the default order used to display search results in the clients per model
+   name.
 
 .. attribute:: Reference.search_context
 

trytond/model/fields/reference.py

@@ -85,7 +85,11 @@ class Reference(SelectionMixin, Field):
 
     @search_order.setter
     def search_order(self, value):
-        search_order_validate(value)
+        if value is None:
+            value = {}
+        assert isinstance(value, dict)
+        for order in value.values():
+            search_order_validate(order)
         self.__search_order = value
 
     @property