diff options
| -rw-r--r-- | lib/sqlalchemy/orm/mapper.py | 9 | ||||
| -rw-r--r-- | test/orm/test_mapper.py | 13 |
2 files changed, 22 insertions, 0 deletions
diff --git a/lib/sqlalchemy/orm/mapper.py b/lib/sqlalchemy/orm/mapper.py index 74d8f3860..eb5abbd4f 100644 --- a/lib/sqlalchemy/orm/mapper.py +++ b/lib/sqlalchemy/orm/mapper.py @@ -974,6 +974,15 @@ class Mapper(InspectionAttr): self._all_tables = self.inherits._all_tables if self.polymorphic_identity is not None: + if self.polymorphic_identity in self.polymorphic_map: + util.warn( + "Reassigning polymorphic association for identity %r " + "from %r to %r: Check for duplicate use of %r as " + "value for polymorphic_identity." % + (self.polymorphic_identity, + self.polymorphic_map[self.polymorphic_identity], + self, self.polymorphic_identity) + ) self.polymorphic_map[self.polymorphic_identity] = self else: diff --git a/test/orm/test_mapper.py b/test/orm/test_mapper.py index 63ba1a207..264b386d4 100644 --- a/test/orm/test_mapper.py +++ b/test/orm/test_mapper.py @@ -716,6 +716,19 @@ class MapperTest(_fixtures.FixtureTest, AssertsCompiledSQL): m3.identity_key_from_instance(AddressUser()) ) + def test_reassign_polymorphic_identity_warns(self): + User = self.classes.User + users = self.tables.users + class MyUser(User): + pass + m1 = mapper(User, users, polymorphic_on=users.c.name, + polymorphic_identity='user') + assert_raises_message( + sa.exc.SAWarning, + "Reassigning polymorphic association for identity 'user'", + mapper, + MyUser, users, inherits=User, polymorphic_identity='user' + ) def test_illegal_non_primary(self): |