- Fixed previously untested function which regressed

in 0.7, can now make a synonym() of a synonym()
again.

CHANGES

@@ -15,6 +15,10 @@ CHANGES
      when the Session.is_active is True.
      [ticket:2241]
 
+  - Fixed previously untested function which regressed
+    in 0.7, can now make a synonym() of a synonym()
+    again.
+
   - Identity map .discard() uses dict.pop(,None) 
     internally instead of "del" to avoid KeyError/warning 
     during a non-determinate gc teardown [ticket:2267]

lib/sqlalchemy/orm/descriptor_props.py

@@ -360,6 +360,8 @@ class SynonymProperty(DescriptorProperty):
 
         if self.comparator_factory:
             comp = self.comparator_factory(prop, mapper)
+        elif isinstance(prop, DescriptorProperty):
+            comp = prop._comparator_factory(mapper)
         else:
             comp = prop.comparator_factory(prop, mapper)
         return comp

test/orm/test_mapper.py

@@ -1074,6 +1074,20 @@ class MapperTest(_fixtures.FixtureTest):
         eq_(User.uname.attribute, 123)
         eq_(User.uname['key'], 'value')
 
+    def test_synonym_of_synonym(self):
+        users,  User = (self.tables.users,
+                                self.classes.User)
+
+        mapper(User, users, properties={
+            'x':synonym('id'),
+            'y':synonym('x')
+        })
+
+        s = Session()
+        u = s.query(User).filter(User.y==8).one()
+        eq_(u.y, 8)
+
+
     def test_synonym_column_location(self):
         users, User = self.tables.users, self.classes.User