diff options
Diffstat (limited to 'lib/sqlalchemy/orm/mapper.py')
| -rw-r--r-- | lib/sqlalchemy/orm/mapper.py | 23 |
1 files changed, 20 insertions, 3 deletions
diff --git a/lib/sqlalchemy/orm/mapper.py b/lib/sqlalchemy/orm/mapper.py index 36b97cf17..5d784498a 100644 --- a/lib/sqlalchemy/orm/mapper.py +++ b/lib/sqlalchemy/orm/mapper.py @@ -1224,10 +1224,27 @@ class Mapper( else: self.persist_selectable = self.local_table - if self.polymorphic_identity is not None and not self.concrete: - self._identity_class = self.inherits._identity_class - else: + if self.polymorphic_identity is None: + self._identity_class = self.class_ + + if self.inherits.base_mapper.polymorphic_on is not None: + util.warn( + "Mapper %s does not indicate a polymorphic_identity, " + "yet is part of an inheritance hierarchy that has a " + "polymorphic_on column of '%s'. Objects of this type " + "cannot be loaded polymorphically which can lead to " + "degraded or incorrect loading behavior in some " + "scenarios. Please establish a polmorphic_identity " + "for this class, or leave it un-mapped. " + "To omit mapping an intermediary class when using " + "declarative, set the '__abstract__ = True' " + "attribute on that class." + % (self, self.inherits.base_mapper.polymorphic_on) + ) + elif self.concrete: self._identity_class = self.class_ + else: + self._identity_class = self.inherits._identity_class if self.version_id_col is None: self.version_id_col = self.inherits.version_id_col |