1 files changed, 90 insertions, 0 deletions
diff --git a/test/orm/inheritance/test_basic.py b/test/orm/inheritance/test_basic.py
index ebb485156..831781330 100644
--- a/test/orm/inheritance/test_basic.py
+++ b/test/orm/inheritance/test_basic.py
@@ -3410,6 +3410,96 @@ class DiscriminatorOrPkNoneTest(fixtures.DeclarativeMappedTest):
         )
 
 
+class UnexpectedPolymorphicIdentityTest(fixtures.DeclarativeMappedTest):
+    run_setup_mappers = "once"
+    __dialect__ = "default"
+
+    @classmethod
+    def setup_classes(cls):
+        Base = cls.DeclarativeBasic
+
+        class AJoined(fixtures.ComparableEntity, Base):
+            __tablename__ = "ajoined"
+            id = Column(Integer, primary_key=True)
+            type = Column(String(10), nullable=False)
+            __mapper_args__ = {
+                "polymorphic_on": type,
+                "polymorphic_identity": "a",
+            }
+
+        class AJoinedSubA(AJoined):
+            __tablename__ = "ajoinedsuba"
+            id = Column(ForeignKey("ajoined.id"), primary_key=True)
+            __mapper_args__ = {"polymorphic_identity": "suba"}
+
+        class AJoinedSubB(AJoined):
+            __tablename__ = "ajoinedsubb"
+            id = Column(ForeignKey("ajoined.id"), primary_key=True)
+            __mapper_args__ = {"polymorphic_identity": "subb"}
+
+        class ASingle(fixtures.ComparableEntity, Base):
+            __tablename__ = "asingle"
+            id = Column(Integer, primary_key=True)
+            type = Column(String(10), nullable=False)
+            __mapper_args__ = {
+                "polymorphic_on": type,
+                "polymorphic_identity": "a",
+            }
+
+        class ASingleSubA(ASingle):
+            __mapper_args__ = {"polymorphic_identity": "suba"}
+
+        class ASingleSubB(ASingle):
+            __mapper_args__ = {"polymorphic_identity": "subb"}
+
+    @classmethod
+    def insert_data(cls):
+        ASingleSubA, ASingleSubB, AJoinedSubA, AJoinedSubB = cls.classes(
+            "ASingleSubA", "ASingleSubB", "AJoinedSubA", "AJoinedSubB"
+        )
+        s = Session()
+
+        s.add_all([ASingleSubA(), ASingleSubB(), AJoinedSubA(), AJoinedSubB()])
+        s.commit()
+
+    def test_single_invalid_ident(self):
+        ASingle, ASingleSubA = self.classes("ASingle", "ASingleSubA")
+
+        s = Session()
+
+        q = s.query(ASingleSubA).select_entity_from(
+            select([ASingle]).subquery()
+        )
+
+        assert_raises_message(
+            sa_exc.InvalidRequestError,
+            r"Row with identity key \(.*ASingle.*\) can't be loaded into an "
+            r"object; the polymorphic discriminator column '.*.type' refers "
+            r"to mapped class ASingleSubB->asingle, which is not a "
+            r"sub-mapper of the requested mapped class ASingleSubA->asingle",
+            q.all,
+        )
+
+    def test_joined_invalid_ident(self):
+        AJoined, AJoinedSubA = self.classes("AJoined", "AJoinedSubA")
+
+        s = Session()
+
+        q = s.query(AJoinedSubA).select_entity_from(
+            select([AJoined]).subquery()
+        )
+
+        assert_raises_message(
+            sa_exc.InvalidRequestError,
+            r"Row with identity key \(.*AJoined.*\) can't be loaded into an "
+            r"object; the polymorphic discriminator column '.*.type' refers "
+            r"to mapped class AJoinedSubB->ajoinedsubb, which is not a "
+            r"sub-mapper of the requested mapped class "
+            r"AJoinedSubA->ajoinedsuba",
+            q.all,
+        )
+
+
 class NameConflictTest(fixtures.MappedTest):
     @classmethod
     def define_tables(cls, metadata):