- Fixed a bug involving the new flattened JOIN structures which

are used with :func:`.joinedload()` (thereby causing a regression
in joined eager loading) as well as :func:`.aliased`
in conjunction with the ``flat=True`` flag and joined-table inheritance;
basically multiple joins across a "parent JOIN sub" entity using different
paths to get to a target class wouldn't form the correct ON conditions.
An adjustment / simplification made in the mechanics of figuring
out the "left side" of the join in the case of an aliased, joined-inh
class repairs the issue. [ticket:2908]

1 files changed, 3 insertions, 4 deletions

diff --git a/lib/sqlalchemy/orm/relationships.py b/lib/sqlalchemy/orm/relationships.py
index 982f10a4d..6fdedd382 100644
--- a/lib/sqlalchemy/orm/relationships.py
+++ b/lib/sqlalchemy/orm/relationships.py
@@ -747,11 +747,10 @@ class RelationshipProperty(StrategizedProperty):
             return self.property.parent
 
         def _source_selectable(self):
-            elem = self.property.parent._with_polymorphic_selectable
-            if self.adapter:
-                return self.adapter(elem)
+            if self._adapt_to_entity:
+                return self._adapt_to_entity.selectable
             else:
-                return elem
+                return self.property.parent._with_polymorphic_selectable
 
         def __clause_element__(self):
             adapt_from = self._source_selectable()