diff options
Diffstat (limited to 'lib/sqlalchemy/orm/loading.py')
| -rw-r--r-- | lib/sqlalchemy/orm/loading.py | 40 |
1 files changed, 33 insertions, 7 deletions
diff --git a/lib/sqlalchemy/orm/loading.py b/lib/sqlalchemy/orm/loading.py index b823de4ab..218449cdd 100644 --- a/lib/sqlalchemy/orm/loading.py +++ b/lib/sqlalchemy/orm/loading.py @@ -643,11 +643,9 @@ def _instance_processor( identity_token, ) if not is_not_primary_key(identitykey[1]): - raise sa_exc.InvalidRequestError( - "Row with identity key %s can't be loaded into an " - "object; the polymorphic discriminator column '%s' is " - "NULL" % (identitykey, polymorphic_discriminator) - ) + return identitykey + else: + return None _instance = _decorate_polymorphic_switch( _instance, @@ -843,6 +841,8 @@ def _decorate_polymorphic_switch( else: if sub_mapper is mapper: return None + elif not sub_mapper.isa(mapper): + return False return _instance_processor( sub_mapper, @@ -863,11 +863,37 @@ def _decorate_polymorphic_switch( _instance = polymorphic_instances[discriminator] if _instance: return _instance(row) + elif _instance is False: + identitykey = ensure_no_pk(row) + + if identitykey: + raise sa_exc.InvalidRequestError( + "Row with identity key %s can't be loaded into an " + "object; the polymorphic discriminator column '%s' " + "refers to %s, which is not a sub-mapper of " + "the requested %s" + % ( + identitykey, + polymorphic_on, + mapper.polymorphic_map[discriminator], + mapper, + ) + ) + else: + return None else: return instance_fn(row) else: - ensure_no_pk(row) - return None + identitykey = ensure_no_pk(row) + + if identitykey: + raise sa_exc.InvalidRequestError( + "Row with identity key %s can't be loaded into an " + "object; the polymorphic discriminator column '%s' is " + "NULL" % (identitykey, polymorphic_on) + ) + else: + return None return polymorphic_instance |