- Made a small improvement to the heuristics of relationship when

determining remote side with semi-self-referential (e.g. two joined
inh subclasses referring to each other), non-simple join conditions
such that the parententity is taken into account and can reduce the
need for using the ``remote()`` annotation; this can restore some
cases that might have worked without the annotation prior to 0.9.4
via :ticket:`2948`. fixes #3364

1 files changed, 9 insertions, 0 deletions

diff --git a/lib/sqlalchemy/orm/relationships.py b/lib/sqlalchemy/orm/relationships.py
index e36a644da..b649c9e21 100644
--- a/lib/sqlalchemy/orm/relationships.py
+++ b/lib/sqlalchemy/orm/relationships.py
@@ -2329,12 +2329,21 @@ class JoinCondition(object):
             binary.right, binary.left = proc_left_right(binary.right,
                                                         binary.left)
 
+        check_entities = self.prop is not None and \
+            self.prop.mapper is not self.prop.parent
+
         def proc_left_right(left, right):
             if isinstance(left, expression.ColumnClause) and \
                     isinstance(right, expression.ColumnClause):
                 if self.child_selectable.c.contains_column(right) and \
                         self.parent_selectable.c.contains_column(left):
                     right = right._annotate({"remote": True})
+            elif check_entities and \
+                    right._annotations.get('parentmapper') is self.prop.mapper:
+                right = right._annotate({"remote": True})
+            elif check_entities and \
+                    left._annotations.get('parentmapper') is self.prop.mapper:
+                left = left._annotate({"remote": True})
             else:
                 self._warn_non_column_elements()