- expand the check to determine if a selectable column is embedded

in the corresponding selectable to take into account clones
of the target column.  fixes [ticket:2419]
- have _make_proxy() copy out the _is_clone_of attribute on the
new column so that even more corresponding_column() checks
work as expected for cloned elements.
- add a new test fixture so that mapped tests can be specified
using declarative.

1 files changed, 2 insertions, 0 deletions

diff --git a/lib/sqlalchemy/schema.py b/lib/sqlalchemy/schema.py
index 3ae0053c3..154e18e5f 100644
--- a/lib/sqlalchemy/schema.py
+++ b/lib/sqlalchemy/schema.py
@@ -1122,6 +1122,8 @@ class Column(SchemaItem, expression.ColumnClause):
 
         c.table = selectable
         selectable._columns.add(c)
+        if selectable._is_clone_of is not None:
+            c._is_clone_of = selectable._is_clone_of.columns[c.name]
         if self.primary_key:
             selectable.primary_key.add(c)
         c.dispatch.after_parent_attach(c, selectable)