- assert passive_deletes='all' does not affect collection/scalar

membership removal

in issue #3844 we hypotheized that passive_deletes='all' was broken
because it sets to NULL a foreign key attribute when the child
object is removed or replaced.   However, not doing the NULL
set means that nothing happens at all and the operation silently
fails.

Change-Id: I11834e7e324349e172dc797bac62731008b6b95a

2 files changed, 33 insertions, 27 deletions

diff --git a/lib/sqlalchemy/orm/relationships.py b/lib/sqlalchemy/orm/relationships.py
index 97adf4d8b..94c0d6694 100644
--- a/lib/sqlalchemy/orm/relationships.py
+++ b/lib/sqlalchemy/orm/relationships.py
@@ -626,13 +626,14 @@ class RelationshipProperty(StrategizedProperty):
            database side.
 
            Additionally, setting the flag to the string value 'all' will
-           disable the "nulling out" of the child foreign keys, when there
-           is no delete or delete-orphan cascade enabled.  This is
-           typically used when a triggering or error raise scenario is in
-           place on the database side.  Note that the foreign key
-           attributes on in-session child objects will not be changed
-           after a flush occurs so this is a very special use-case
-           setting.
+           disable the "nulling out" of the child foreign keys, when the parent
+           object is deleted and there is no delete or delete-orphan cascade
+           enabled.  This is typically used when a triggering or error raise
+           scenario is in place on the database side.  Note that the foreign
+           key attributes on in-session child objects will not be changed after
+           a flush occurs so this is a very special use-case setting.
+           Additionally, the "nulling out" will still occur if the child
+           object is de-associated with the parent.
 
            .. seealso::
 
diff --git a/test/orm/test_unitofwork.py b/test/orm/test_unitofwork.py
index 74014781b..09f64c108 100644
--- a/test/orm/test_unitofwork.py
+++ b/test/orm/test_unitofwork.py
@@ -695,26 +695,6 @@ class ExtraPassiveDeletesTest(fixtures.MappedTest):
         class MyOtherClass(cls.Basic):
             pass
 
-    def test_assertions(self):
-        myothertable, MyOtherClass = (self.tables.myothertable,
-                                      self.classes.MyOtherClass)
-        mytable, MyClass = self.tables.mytable, self.classes.MyClass
-
-        mapper(MyClass, mytable, properties={
-            'foo': relationship(MyOtherClass,
-                                passive_deletes='all',
-                                cascade="all")
-        })
-        mapper(MyOtherClass, myothertable)
-
-        assert_raises_message(
-            sa.exc.ArgumentError,
-            "On MyClass.foo, can't set passive_deletes='all' in conjunction "
-            "with 'delete' "
-            "or 'delete-orphan' cascade",
-            sa.orm.configure_mappers
-        )
-
     def test_extra_passive(self):
         myothertable, MyClass, MyOtherClass, mytable = (
             self.tables.myothertable,
@@ -770,6 +750,31 @@ class ExtraPassiveDeletesTest(fixtures.MappedTest):
         mc.children[0].data = 'some new data'
         assert_raises(sa.exc.DBAPIError, session.flush)
 
+    def test_extra_passive_obj_removed_o2m_still_nulls_out(self):
+        # see #3844, which we decided was not a bug
+        myothertable, MyClass, MyOtherClass, mytable = (
+            self.tables.myothertable,
+            self.classes.MyClass,
+            self.classes.MyOtherClass,
+            self.tables.mytable)
+
+        mapper(MyOtherClass, myothertable)
+        mapper(MyClass, mytable, properties={
+            'children': relationship(MyOtherClass,
+                                  passive_deletes='all')})
+
+        session = create_session()
+        mc = MyClass()
+        moc = MyOtherClass()
+        mc.children.append(moc)
+        session.add_all([mc, moc])
+        session.flush()
+
+        mc.children.remove(moc)
+        session.flush()
+
+        eq_(moc.parent_id, None)
+
     def test_dont_emit(self):
         myothertable, MyClass, MyOtherClass, mytable = (
             self.tables.myothertable,