- Arguments in __mapper_args__ that aren't "hashable"

aren't mistaken for always-hashable, possibly-column
arguments.  [ticket:2091]

1 files changed, 6 insertions, 4 deletions

diff --git a/lib/sqlalchemy/ext/declarative.py b/lib/sqlalchemy/ext/declarative.py
index 0372d4dac..e521ddbbf 100755
--- a/lib/sqlalchemy/ext/declarative.py
+++ b/lib/sqlalchemy/ext/declarative.py
@@ -782,7 +782,7 @@ it as part of ``__table_args__``::
     class MyMixin(object):
         a =  Column(Integer)
         b =  Column(Integer)
-        
+
         @declared_attr
         def __table_args__(cls):
             return (Index('test_idx_%s' % cls.__tablename__, 'a', 'b'),)
@@ -944,9 +944,10 @@ def _as_declarative(cls, classname, dict_):
 
     # make sure that column copies are used rather 
     # than the original columns from any mixins
-    for k, v in mapper_args.iteritems():
-        mapper_args[k] = column_copies.get(v,v)
-
+    for k in ('version_id_col', 'polymorphic_on',):
+        if k in mapper_args:
+            v = mapper_args[k]
+            mapper_args[k] = column_copies.get(v,v)
 
     if classname in cls._decl_class_registry:
         util.warn("The classname %r is already in the registry of this"
@@ -1122,6 +1123,7 @@ def _as_declarative(cls, classname, dict_):
                     # change this ordering when we do [ticket:1892]
                     our_stuff[k] = p.columns + [col]
 
+
     cls.__mapper__ = mapper_cls(cls, 
                                 table, 
                                 properties=our_stuff,