- Two fixes to help prevent out-of-band columns from

being rendered in polymorphic_union inheritance
scenarios (which then causes extra tables to be
rendered in the FROM clause causing cartesian
products):
- improvements to "column adaption" for
  a->b->c inheritance situations to better
  locate columns that are related to one
  another via multiple levels of indirection,
  rather than rendering the non-adapted
  column.
- the "polymorphic discriminator" column is
  only rendered for the actual mapper being
  queried against. The column won't be
  "pulled in" from a subclass or superclass
  mapper since it's not needed.

1 files changed, 26 insertions, 0 deletions

diff --git a/test/sql/generative.py b/test/sql/generative.py
index f6b849e8a..4edf334f6 100644
--- a/test/sql/generative.py
+++ b/test/sql/generative.py
@@ -458,6 +458,32 @@ class ClauseAdapterTest(TestBase, AssertsCompiledSQL):
 
         assert str(e) == "a_1.id = a.xxx_id"
 
+    def test_recursive_equivalents(self):
+        m = MetaData()
+        a = Table('a', m, Column('x', Integer), Column('y', Integer))
+        b = Table('b', m, Column('x', Integer), Column('y', Integer))
+        c = Table('c', m, Column('x', Integer), Column('y', Integer))
+        
+        # force a recursion overflow, by linking a.c.x<->c.c.x, and
+        # asking for a nonexistent col.  corresponding_column should prevent
+        # endless depth.
+        adapt = sql_util.ClauseAdapter( b, equivalents= {a.c.x: set([ c.c.x]), c.c.x:set([a.c.x])})
+        assert adapt._corresponding_column(a.c.x, False) is None
+
+    def test_multilevel_equivalents(self):
+        m = MetaData()
+        a = Table('a', m, Column('x', Integer), Column('y', Integer))
+        b = Table('b', m, Column('x', Integer), Column('y', Integer))
+        c = Table('c', m, Column('x', Integer), Column('y', Integer))
+
+        alias = select([a]).select_from(a.join(b, a.c.x==b.c.x)).alias()
+        
+        # two levels of indirection from c.x->b.x->a.x, requires recursive 
+        # corresponding_column call
+        adapt = sql_util.ClauseAdapter(alias, equivalents= {b.c.x: set([ a.c.x]), c.c.x:set([b.c.x])})
+        assert adapt._corresponding_column(a.c.x, False) is alias.c.x
+        assert adapt._corresponding_column(c.c.x, False) is alias.c.x
+        
     def test_join_to_alias(self):
         metadata = MetaData()
         a = Table('a', metadata,