Accommodate for classically mapped base classes in declarative

Fixed issue in previously untested use case, allowing a declarative mapped
class to inherit from a classically-mapped class outside of the declarative
base, including that it accommodates for unmapped intermediate classes. An
unmapped intermediate class may specify ``__abstract__``, which is now
interpreted correctly, or the intermediate class can remain unmarked, and
the classically mapped base class will be detected within the hierarchy
regardless. In order to anticipate existing scenarios which may be mixing
in classical mappings into existing declarative hierarchies, an error is
now raised if multiple mapped bases are detected for a given class.

Fixes: #4321
Change-Id: I8604ecfd170d2589d9d1b1c87ba303762071fc30

1 files changed, 91 insertions, 2 deletions

diff --git a/test/ext/declarative/test_inheritance.py b/test/ext/declarative/test_inheritance.py
index 7ced8ec15..c310b725f 100644
--- a/test/ext/declarative/test_inheritance.py
+++ b/test/ext/declarative/test_inheritance.py
@@ -1,5 +1,5 @@
 
-from sqlalchemy.testing import eq_, assert_raises, \
+from sqlalchemy.testing import eq_, le_, assert_raises, \
     assert_raises_message, is_, is_true, is_false
 from sqlalchemy.ext import declarative as decl
 import sqlalchemy as sa
@@ -8,7 +8,7 @@ from sqlalchemy import Integer, String, ForeignKey
 from sqlalchemy.testing.schema import Table, Column
 from sqlalchemy.orm import relationship, create_session, class_mapper, \
     configure_mappers, clear_mappers, \
-    polymorphic_union, deferred, Session
+    polymorphic_union, deferred, Session, mapper
 from sqlalchemy.ext.declarative import declared_attr, AbstractConcreteBase, \
     ConcreteBase, has_inherited_table
 from sqlalchemy.testing import fixtures, mock
@@ -290,6 +290,95 @@ class DeclarativeInheritanceTest(DeclarativeTestBase):
 
         assert class_mapper(Engineer).inherits is class_mapper(Person)
 
+    def test_intermediate_abstract_class_on_classical(self):
+        class Person(object):
+            pass
+
+        person_table = Table('people', Base.metadata,
+                             Column('id', Integer, primary_key=True),
+                             Column('kind', String(50)))
+
+        mapper(Person, person_table,
+               polymorphic_on='kind', polymorphic_identity='person')
+
+        class SpecialPerson(Person):
+            __abstract__ = True
+
+        class Manager(SpecialPerson, Base):
+            __tablename__ = 'managers'
+            id = Column(Integer, ForeignKey(Person.id), primary_key=True)
+            __mapper_args__ = {
+                'polymorphic_identity': 'manager'
+            }
+
+        from sqlalchemy import inspect
+        assert inspect(Manager).inherits is inspect(Person)
+
+        eq_(set(class_mapper(Person).class_manager), {'id', 'kind'})
+        eq_(set(class_mapper(Manager).class_manager), {'id', 'kind'})
+
+    def test_intermediate_unmapped_class_on_classical(self):
+        class Person(object):
+            pass
+
+        person_table = Table('people', Base.metadata,
+                             Column('id', Integer, primary_key=True),
+                             Column('kind', String(50)))
+
+        mapper(Person, person_table,
+               polymorphic_on='kind', polymorphic_identity='person')
+
+        class SpecialPerson(Person):
+            pass
+
+        class Manager(SpecialPerson, Base):
+            __tablename__ = 'managers'
+            id = Column(Integer, ForeignKey(Person.id), primary_key=True)
+            __mapper_args__ = {
+                'polymorphic_identity': 'manager'
+            }
+
+        from sqlalchemy import inspect
+        assert inspect(Manager).inherits is inspect(Person)
+
+        eq_(set(class_mapper(Person).class_manager), {'id', 'kind'})
+        eq_(set(class_mapper(Manager).class_manager), {'id', 'kind'})
+
+    def test_class_w_invalid_multiple_bases(self):
+        class Person(object):
+            pass
+
+        person_table = Table('people', Base.metadata,
+                             Column('id', Integer, primary_key=True),
+                             Column('kind', String(50)))
+
+        mapper(Person, person_table,
+               polymorphic_on='kind', polymorphic_identity='person')
+
+        class DeclPerson(Base):
+            __tablename__ = 'decl_people'
+            id = Column(Integer, primary_key=True)
+            kind = Column(String(50))
+
+        class SpecialPerson(Person):
+            pass
+
+        def go():
+            class Manager(SpecialPerson, DeclPerson):
+                __tablename__ = 'managers'
+                id = Column(Integer,
+                            ForeignKey(DeclPerson.id), primary_key=True)
+                __mapper_args__ = {
+                    'polymorphic_identity': 'manager'
+                }
+
+        assert_raises_message(
+            sa.exc.InvalidRequestError,
+            r"Class .*Manager.* has multiple mapped "
+            r"bases: \[.*Person.*DeclPerson.*\]",
+            go
+        )
+
     def test_with_undefined_foreignkey(self):
 
         class Parent(Base):