- a forward and complementing backwards reference which are both

of the same direction, i.e. ONETOMANY or MANYTOONE,
is now detected, and an error message is raised.
Saves crazy CircularDependencyErrors later on.

diff --git a/CHANGES b/CHANGES
index 921fbec76b882b35ce3c5f6fb308ee036f7d21f9..14a9c16ab6d2974a998deb38b9d120fc36a75593 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -42,7 +42,12 @@ CHANGES
     - Added "post_configure_attribute" method to InstrumentationManager,
       so that the "listen_for_events.py" example works again.
       [ticket:1314]
-      
+    
+    - a forward and complementing backwards reference which are both
+      of the same direction, i.e. ONETOMANY or MANYTOONE, 
+      is now detected, and an error message is raised.   
+      Saves crazy CircularDependencyErrors later on.
+        
     - Fixed bugs in Query regarding simultaneous selection of 
       multiple joined-table inheritance entities with common base 
       classes:

diff --git a/lib/sqlalchemy/orm/properties.py b/lib/sqlalchemy/orm/properties.py
index 9c2268e01493e4b7d4ee7517d0ece379aee8b5fb..3ae0bfbf5eabfd30582b51acf5be360471a08ee5 100644 (file)
--- a/lib/sqlalchemy/orm/properties.py
+++ b/lib/sqlalchemy/orm/properties.py
@@ -703,6 +703,10 @@ class RelationProperty(StrategizedProperty):
             raise sa_exc.ArgumentError("reverse_property %r on relation %s references "
                     "relation %s, which does not reference mapper %s" % (key, self, other, self.parent))
         
+        if self.direction in (ONETOMANY, MANYTOONE) and self.direction == other.direction:
+            raise sa_exc.ArgumentError("%s and back-reference %s are both of the same direction %r."
+                " Did you mean to set remote_side on the many-to-one side ?" % (self, other, self.direction))
+        
     def do_init(self):
         self._get_target()
         self._process_dependent_arguments()

diff --git a/test/orm/mapper.py b/test/orm/mapper.py
index c1d422ec0ab351c6e6182ff8344dc533476897a1..59ae025cb30a044dc433ea96ce2af857adb0f249 100644 (file)
--- a/test/orm/mapper.py
+++ b/test/orm/mapper.py
@@ -447,7 +447,7 @@ class MapperTest(_fixtures.FixtureTest):
                      include_properties=('id', 'type', 'name'))
         e_m = mapper(Employee, inherits=p_m, polymorphic_identity='employee',
           properties={
-            'boss': relation(Manager, backref='peon')
+            'boss': relation(Manager, backref=backref('peon', ), remote_side=t.c.id)
           },
           exclude_properties=('vendor_id',))
 

diff --git a/test/orm/relationships.py b/test/orm/relationships.py
index 9787216f73274e4eb31460e020c47ab813ce97a6..88f132eae25d31add9eaacf138e821f4a6b2c01d 100644 (file)
--- a/test/orm/relationships.py
+++ b/test/orm/relationships.py
@@ -1519,7 +1519,64 @@ class ExplicitLocalRemoteTest(_base.MappedTest):
         mapper(T2, t2)
         self.assertRaises(sa.exc.ArgumentError, sa.orm.compile_mappers)
 
+class InvalidRemoteSideTest(_base.MappedTest):
+    def define_tables(self, metadata):
+        Table('t1', metadata,
+            Column('id', Integer, primary_key=True),
+            Column('data', String(50)),
+            Column('t_id', Integer, ForeignKey('t1.id'))
+            )
 
+    @testing.resolve_artifact_names
+    def setup_classes(self):
+        class T1(_base.ComparableEntity):
+            pass
+
+    @testing.resolve_artifact_names
+    def test_o2m_backref(self):
+        mapper(T1, t1, properties={
+            't1s':relation(T1, backref='parent')
+        })
+
+        self.assertRaisesMessage(sa.exc.ArgumentError, "T1.t1s and back-reference T1.parent are "
+                    "both of the same direction <symbol 'ONETOMANY>.  Did you "
+                    "mean to set remote_side on the many-to-one side ?", sa.orm.compile_mappers)
+
+    @testing.resolve_artifact_names
+    def test_m2o_backref(self):
+        mapper(T1, t1, properties={
+            't1s':relation(T1, backref=backref('parent', remote_side=t1.c.id), remote_side=t1.c.id)
+        })
+
+        self.assertRaisesMessage(sa.exc.ArgumentError, "T1.t1s and back-reference T1.parent are "
+                    "both of the same direction <symbol 'MANYTOONE>.  Did you "
+                    "mean to set remote_side on the many-to-one side ?", sa.orm.compile_mappers)
+
+    @testing.resolve_artifact_names
+    def test_o2m_explicit(self):
+        mapper(T1, t1, properties={
+            't1s':relation(T1, back_populates='parent'),
+            'parent':relation(T1, back_populates='t1s'),
+        })
+
+        # can't be sure of ordering here
+        self.assertRaisesMessage(sa.exc.ArgumentError, 
+                    "both of the same direction <symbol 'ONETOMANY>.  Did you "
+                    "mean to set remote_side on the many-to-one side ?", sa.orm.compile_mappers)
+
+    @testing.resolve_artifact_names
+    def test_m2o_explicit(self):
+        mapper(T1, t1, properties={
+            't1s':relation(T1, back_populates='parent', remote_side=t1.c.id),
+            'parent':relation(T1, back_populates='t1s', remote_side=t1.c.id)
+        })
+
+        # can't be sure of ordering here
+        self.assertRaisesMessage(sa.exc.ArgumentError, 
+                    "both of the same direction <symbol 'MANYTOONE>.  Did you "
+                    "mean to set remote_side on the many-to-one side ?", sa.orm.compile_mappers)
+
+        
 class InvalidRelationEscalationTest(_base.MappedTest):
 
     def define_tables(self, metadata):