- Fixed bug where Query would crash if a join() with no clear

"left" side were called when a non-mapped column entity
appeared in the columns list. [ticket:1602]

1 files changed, 5 insertions, 2 deletions

diff --git a/lib/sqlalchemy/orm/query.py b/lib/sqlalchemy/orm/query.py
index 0463c548a..03da99568 100644
--- a/lib/sqlalchemy/orm/query.py
+++ b/lib/sqlalchemy/orm/query.py
@@ -2129,10 +2129,13 @@ class _ColumnEntity(_QueryEntity):
         self.froms.add(from_obj)
 
     def corresponds_to(self, entity):
-        if _is_aliased_class(entity):
+        if self.entity_zero is None:
+            return False
+        elif _is_aliased_class(entity):
             return entity is self.entity_zero
         else:
-            return not _is_aliased_class(self.entity_zero) and entity.base_mapper.common_parent(self.entity_zero)
+            return not _is_aliased_class(self.entity_zero) and \
+                    entity.base_mapper.common_parent(self.entity_zero)
 
     def _resolve_expr_against_query_aliases(self, query, expr, context):
         return query._adapt_clause(expr, False, True)