- Fixed bug where :class:`.AbstractConcreteBase` would fail to be

fully usable within declarative relationship configuration, as its
string classname would not be available in the registry of classnames
at mapper configuration time.   The class now explicitly adds itself
to the class regsitry, and additionally both :class:`.AbstractConcreteBase`
as well as :class:`.ConcreteBase` set themselves up *before* mappers
are configured within the :func:`.configure_mappers` setup, using
the new :meth:`.MapperEvents.before_configured` event. [ticket:2950]

- Added new :meth:`.MapperEvents.before_configured` event which allows
an event at the start of :func:`.configure_mappers`, as well
as ``__declare_first__()`` hook within declarative to complement
``__declare_last__()``.

- modified how after_configured is invoked; we just make a dispatch()
not actually connected to any mapper.  this makes it easier
to also invoke before_configured correctly.

- improved the ComparableEntity fixture to handle collections that are sets.

1 files changed, 78 insertions, 0 deletions

diff --git a/test/ext/declarative/test_inheritance.py b/test/ext/declarative/test_inheritance.py
index 01bf3f3f6..22dd32e45 100644
--- a/test/ext/declarative/test_inheritance.py
+++ b/test/ext/declarative/test_inheritance.py
@@ -1201,3 +1201,81 @@ class ConcreteInhTest(_RemoveListeners, DeclarativeTestBase):
             __mapper_args__ = {'polymorphic_identity': "engineer",
                             'concrete': True}
         self._roundtrip(Employee, Manager, Engineer, Boss, explicit_type=True)
+
+class ConcreteExtensionConfigTest(_RemoveListeners, testing.AssertsCompiledSQL, DeclarativeTestBase):
+    __dialect__ = 'default'
+
+    def test_classreg_setup(self):
+        class A(Base, fixtures.ComparableEntity):
+            __tablename__ = 'a'
+            id = Column(Integer, primary_key=True, test_needs_autoincrement=True)
+            data = Column(String(50))
+            collection = relationship("BC", primaryjoin="BC.a_id == A.id",
+                            collection_class=set)
+
+        class BC(AbstractConcreteBase, Base, fixtures.ComparableEntity):
+            pass
+
+        class B(BC):
+            __tablename__ = 'b'
+            id = Column(Integer, primary_key=True, test_needs_autoincrement=True)
+
+            a_id = Column(Integer, ForeignKey('a.id'))
+            data = Column(String(50))
+            b_data = Column(String(50))
+            __mapper_args__ = {
+                "polymorphic_identity": "b",
+                "concrete": True
+            }
+
+        class C(BC):
+            __tablename__ = 'c'
+            id = Column(Integer, primary_key=True, test_needs_autoincrement=True)
+            a_id = Column(Integer, ForeignKey('a.id'))
+            data = Column(String(50))
+            c_data = Column(String(50))
+            __mapper_args__ = {
+                "polymorphic_identity": "c",
+                "concrete": True
+            }
+
+        Base.metadata.create_all()
+        sess = Session()
+        sess.add_all([
+            A(data='a1', collection=set([
+                B(data='a1b1', b_data='a1b1'),
+                C(data='a1b2', c_data='a1c1'),
+                B(data='a1b2', b_data='a1b2'),
+                C(data='a1c2', c_data='a1c2'),
+            ])),
+            A(data='a2', collection=set([
+                B(data='a2b1', b_data='a2b1'),
+                C(data='a2c1', c_data='a2c1'),
+                B(data='a2b2', b_data='a2b2'),
+                C(data='a2c2', c_data='a2c2'),
+            ]))
+        ])
+        sess.commit()
+        sess.expunge_all()
+
+        eq_(
+            sess.query(A).filter_by(data='a2').all(),
+            [
+                A(data='a2', collection=set([
+                    B(data='a2b1', b_data='a2b1'),
+                    B(data='a2b2', b_data='a2b2'),
+                    C(data='a2c1', c_data='a2c1'),
+                    C(data='a2c2', c_data='a2c2'),
+                ]))
+            ]
+        )
+
+        self.assert_compile(
+            sess.query(A).join(A.collection),
+            "SELECT a.id AS a_id, a.data AS a_data FROM a JOIN "
+            "(SELECT c.id AS id, c.a_id AS a_id, c.data AS data, "
+                "c.c_data AS c_data, CAST(NULL AS VARCHAR(50)) AS b_data, "
+                "'c' AS type FROM c UNION ALL SELECT b.id AS id, b.a_id AS a_id, "
+                "b.data AS data, CAST(NULL AS VARCHAR(50)) AS c_data, "
+                "b.b_data AS b_data, 'b' AS type FROM b) AS pjoin ON pjoin.a_id = a.id"
+        )