- [bug] with_polymorphic() produces JOINs

in the correct order and with correct inheriting
tables in the case of sending multi-level
subclasses in an arbitrary order or with
intermediary classes missing.  [ticket:1900]

CHANGES

@@ -81,6 +81,12 @@ underneath "0.7.xx".
     contains_eager()
     [ticket:2438] [ticket:1106]
 
+  - [bug] with_polymorphic() produces JOINs
+    in the correct order and with correct inheriting
+    tables in the case of sending multi-level
+    subclasses in an arbitrary order or with
+    intermediary classes missing.  [ticket:1900]
+
   - [feature] The "deferred declarative
     reflection" system has been moved into the
     declarative extension itself, using the

lib/sqlalchemy/orm/mapper.py

@@ -1347,12 +1347,19 @@ class Mapper(_InspectionAttr):
         if spec == '*':
             mappers = list(self.self_and_descendants)
         elif spec:
-            mappers = [_class_to_mapper(m) for m in util.to_list(spec)]
-            for m in mappers:
+            mappers = set()
+            for m in util.to_list(spec):
+                m = _class_to_mapper(m)
                 if not m.isa(self):
                     raise sa_exc.InvalidRequestError(
                                 "%r does not inherit from %r" %
                                 (m, self))
+
+                if selectable is None:
+                    mappers.update(m.iterate_to_root())
+                else:
+                    mappers.add(m)
+            mappers = [m for m in self.self_and_descendants if m in mappers]
         else:
             mappers = []
 

test/orm/inheritance/test_basic.py

@@ -10,6 +10,7 @@ from test.lib import testing, engines
 from test.lib import fixtures
 from test.orm import _fixtures
 from test.lib.schema import Table, Column
+from sqlalchemy import inspect
 from sqlalchemy.ext.declarative import declarative_base
 from test.lib.util import gc_collect
 
@@ -74,6 +75,104 @@ class O2MTest(fixtures.MappedTest):
         eq_(l[0].parent_foo.data, 'foo #1')
         eq_(l[1].parent_foo.data, 'foo #1')
 
+class PolymorphicResolutionMultiLevel(fixtures.DeclarativeMappedTest,
+                                        testing.AssertsCompiledSQL):
+    run_setup_mappers = 'once'
+    __dialect__ = 'default'
+
+    @classmethod
+    def setup_classes(cls):
+        Base = cls.DeclarativeBasic
+        class A(Base):
+            __tablename__ = 'a'
+            id = Column(Integer, primary_key=True)
+        class B(A):
+            __tablename__ = 'b'
+            id = Column(Integer, ForeignKey('a.id'), primary_key=True)
+        class C(A):
+            __tablename__ = 'c'
+            id = Column(Integer, ForeignKey('a.id'), primary_key=True)
+        class D(B):
+            __tablename__ = 'd'
+            id = Column(Integer, ForeignKey('b.id'), primary_key=True)
+
+    def test_ordered_b_d(self):
+        a_mapper = inspect(self.classes.A)
+        eq_(
+            a_mapper._mappers_from_spec(
+                    [self.classes.B, self.classes.D], None),
+            [a_mapper, inspect(self.classes.B), inspect(self.classes.D)]
+        )
+
+    def test_a(self):
+        a_mapper = inspect(self.classes.A)
+        eq_(
+            a_mapper._mappers_from_spec(
+                    [self.classes.A], None),
+            [a_mapper]
+        )
+
+    def test_b_d_selectable(self):
+        a_mapper = inspect(self.classes.A)
+        spec = [self.classes.D, self.classes.B]
+        eq_(
+            a_mapper._mappers_from_spec(
+                    spec,
+                    self.classes.B.__table__.join(self.classes.D.__table__)
+            ),
+            [inspect(self.classes.B), inspect(self.classes.D)]
+        )
+
+    def test_d_selectable(self):
+        a_mapper = inspect(self.classes.A)
+        spec = [self.classes.D]
+        eq_(
+            a_mapper._mappers_from_spec(
+                    spec,
+                    self.classes.B.__table__.join(self.classes.D.__table__)
+            ),
+            [inspect(self.classes.D)]
+        )
+
+    def test_reverse_d_b(self):
+        a_mapper = inspect(self.classes.A)
+        spec = [self.classes.D, self.classes.B]
+        eq_(
+            a_mapper._mappers_from_spec(
+                    spec, None),
+            [a_mapper, inspect(self.classes.B), inspect(self.classes.D)]
+        )
+        mappers, selectable = a_mapper._with_polymorphic_args(spec=spec)
+        self.assert_compile(selectable,
+            "a LEFT OUTER JOIN b ON a.id = b.id "
+            "LEFT OUTER JOIN d ON b.id = d.id")
+
+    def test_d_b_missing(self):
+        a_mapper = inspect(self.classes.A)
+        spec = [self.classes.D]
+        eq_(
+            a_mapper._mappers_from_spec(
+                    spec, None),
+            [a_mapper, inspect(self.classes.B), inspect(self.classes.D)]
+        )
+        mappers, selectable = a_mapper._with_polymorphic_args(spec=spec)
+        self.assert_compile(selectable,
+            "a LEFT OUTER JOIN b ON a.id = b.id "
+            "LEFT OUTER JOIN d ON b.id = d.id")
+
+    def test_d_c_b(self):
+        a_mapper = inspect(self.classes.A)
+        spec = [self.classes.D, self.classes.C, self.classes.B]
+        ms = a_mapper._mappers_from_spec(spec, None)
+
+        eq_(
+            ms[-1], inspect(self.classes.D)
+        )
+        eq_(ms[0], a_mapper)
+        eq_(
+            set(ms[1:3]), set(a_mapper._inheriting_mappers)
+        )
+
 class PolymorphicOnNotLocalTest(fixtures.MappedTest):
     @classmethod
     def define_tables(cls, metadata):