From d78686b4f109fdc78ca6239e5a5af791717bc48d Mon Sep 17 00:00:00 2001 From: Mike Bayer Date: Thu, 27 Aug 2020 15:50:47 -0400 Subject: Raise NotImplemenedError for association proxy __clause_element__ It's not possible right now to use an association proxy element as a plain column expression to be SELECTed from or used in a SQL function. An informative error is now raised when this occurs. Fixes: #5542 Change-Id: I334e767ebc0b56c1dccc4a1e5185b0435af77b93 --- lib/sqlalchemy/ext/associationproxy.py | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'lib/sqlalchemy') diff --git a/lib/sqlalchemy/ext/associationproxy.py b/lib/sqlalchemy/ext/associationproxy.py index dd6217664..3ea77a952 100644 --- a/lib/sqlalchemy/ext/associationproxy.py +++ b/lib/sqlalchemy/ext/associationproxy.py @@ -421,6 +421,12 @@ class AssociationProxyInstance(object): def _comparator(self): return self._get_property().comparator + def __clause_element__(self): + raise NotImplementedError( + "The association proxy can't be used as a plain column " + "expression; it only works inside of a comparison expression" + ) + @classmethod def _cls_unwrap_target_assoc_proxy(cls, target_class, value_attr): attr = getattr(target_class, value_attr) -- cgit v1.2.1