diff options
Diffstat (limited to 'lib/sqlalchemy/orm/query.py')
| -rw-r--r-- | lib/sqlalchemy/orm/query.py | 24 |
1 files changed, 20 insertions, 4 deletions
diff --git a/lib/sqlalchemy/orm/query.py b/lib/sqlalchemy/orm/query.py index 4f10a6ada..3815f5a98 100644 --- a/lib/sqlalchemy/orm/query.py +++ b/lib/sqlalchemy/orm/query.py @@ -1842,14 +1842,30 @@ class Query(object): raise sa_exc.InvalidRequestError( "Can't construct a join from %s to %s, they " "are the same entity" % - (left, right)) + (left, right)) l_info = inspect(left) r_info = inspect(right) - overlap = not create_aliases and \ - sql_util.selectables_overlap(l_info.selectable, - r_info.selectable) + + overlap = False + if not create_aliases: + right_mapper = getattr(r_info, "mapper", None) + # if the target is a joined inheritance mapping, + # be more liberal about auto-aliasing. + if right_mapper and ( + right_mapper.with_polymorphic or + isinstance(right_mapper.mapped_table, expression.Join) + ): + for from_obj in self._from_obj or [l_info.selectable]: + if sql_util.selectables_overlap(l_info.selectable, from_obj) and \ + sql_util.selectables_overlap(from_obj, r_info.selectable): + overlap = True + break + elif sql_util.selectables_overlap(l_info.selectable, r_info.selectable): + overlap = True + + if overlap and l_info.selectable is r_info.selectable: raise sa_exc.InvalidRequestError( "Can't join table/selectable '%s' to itself" % |