- [feature] *Very limited* support for

    inheriting mappers to be GC'ed when the
    class itself is deferenced.  The mapper
    must not have its own table (i.e.
    single table inh only) without polymorphic
    attributes in place.
    This allows for the use case of
    creating a temporary subclass of a declarative
    mapped class, with no table or mapping
    directives of its own, to be garbage collected
    when dereferenced by a unit test.
    [ticket:2526]

1 files changed, 57 insertions, 0 deletions

diff --git a/test/orm/inheritance/test_basic.py b/test/orm/inheritance/test_basic.py
index 0e647a66e..28aced07b 100644
--- a/test/orm/inheritance/test_basic.py
+++ b/test/orm/inheritance/test_basic.py
@@ -11,6 +11,7 @@ from test.lib import fixtures
 from test.orm import _fixtures
 from test.lib.schema import Table, Column
 from sqlalchemy.ext.declarative import declarative_base
+from test.lib.util import gc_collect
 
 class O2MTest(fixtures.MappedTest):
     """deals with inheritance and one-to-many relationships"""
@@ -1695,6 +1696,62 @@ class OptimizedLoadTest(fixtures.MappedTest):
             ),
         )
 
+class TransientInheritingGCTest(fixtures.TestBase):
+    def _fixture(self):
+        Base = declarative_base()
+        class A(Base):
+            __tablename__ = 'a'
+            id = Column(Integer, primary_key=True, test_needs_pk=True)
+            data = Column(String(10))
+        self.A = A
+        return Base
+
+    def setUp(self):
+        self.Base = self._fixture()
+
+    def tearDown(self):
+        self.Base.metadata.drop_all(testing.db)
+        #clear_mappers()
+        self.Base = None
+
+    def _do_test(self, go):
+        B = go()
+        self.Base.metadata.create_all(testing.db)
+        sess = Session(testing.db)
+        sess.add(B(data='some b'))
+        sess.commit()
+
+        b1 = sess.query(B).one()
+        assert isinstance(b1, B)
+        sess.close()
+        del sess
+        del b1
+        del B
+
+        gc_collect()
+
+        eq_(
+            len(self.A.__subclasses__()),
+            0)
+
+    def test_single(self):
+        def go():
+            class B(self.A):
+                pass
+            return B
+        self._do_test(go)
+
+    @testing.fails_if(lambda: True,
+                "not supported for joined inh right now.")
+    def test_joined(self):
+        def go():
+            class B(self.A):
+                __tablename__ = 'b'
+                id = Column(Integer, ForeignKey('a.id'),
+                        primary_key=True)
+            return B
+        self._do_test(go)
+
 class NoPKOnSubTableWarningTest(fixtures.TestBase):
 
     def _fixture(self):