extra test for corresponding column fix

2 files changed, 7 insertions, 0 deletions

diff --git a/lib/sqlalchemy/sql.py b/lib/sqlalchemy/sql.py
index 3a8a27d67..41b61d4af 100644
--- a/lib/sqlalchemy/sql.py
+++ b/lib/sqlalchemy/sql.py
@@ -1734,6 +1734,8 @@ class FromClause(Selectable):
         for co in self._adjusted_exportable_columns():
             cp = self._proxy_column(co)
             for ci in cp.orig_set:
+                # note that some ambiguity is raised here, whereby a selectable might have more than 
+                # one column that maps to an "original" column.  examples include unions and joins
                 self._orig_cols[ci] = cp
         if self.oid_column is not None:
             for ci in self.oid_column.orig_set:
diff --git a/test/sql/selectable.py b/test/sql/selectable.py
index 221d8430c..57ad99886 100755
--- a/test/sql/selectable.py
+++ b/test/sql/selectable.py
@@ -27,6 +27,11 @@ table2 = Table('table2', db,
 )

 

 class SelectableTest(testbase.AssertMixin):

+    def testjoinagainstself(self):

+        jj = select([table.c.col1.label('bar_col1')])

+        jjj = join(table, jj, table.c.col1==jj.c.bar_col1)

+        assert jjj.corresponding_column(jjj.c.table1_col1) is jjj.c.table1_col1

+

     def testjoinagainstjoin(self):

         j  = outerjoin(table, table2, table.c.col1==table2.c.col2)

         jj = select([ table.c.col1.label('bar_col1')],from_obj=[j]).alias('foo')