clarifying some cascade-based unit tests, adding a little more coverage,

and trying to remove unneeded parts of dependency.py cascades.
also de-emphasizing the whole session.flush([oneobject]) thing since i dont really
agree it should be supported

2 files changed, 9 insertions, 36 deletions

diff --git a/lib/sqlalchemy/orm/dependency.py b/lib/sqlalchemy/orm/dependency.py
index 063d5aaa9..e623fd2a1 100644
--- a/lib/sqlalchemy/orm/dependency.py
+++ b/lib/sqlalchemy/orm/dependency.py
@@ -180,9 +180,9 @@ class OneToManyDP(DependencyProcessor):
         if delete:
             # head object is being deleted, and we manage its list of child objects
             # the child objects have to have their foreign key to the parent set to NULL
-            
-            # TODO: this cascade should be "delete" cascade
-            if not self.cascade.delete_orphan or self.post_update:
+            # this phase can be called safely for any cascade but is unnecessary if delete cascade
+            # is on.
+            if not self.cascade.delete or self.post_update:
                 for obj in deplist:
                     childlist = self.get_object_dependencies(obj, uowcommit, passive=self.passive_deletes)
                     if childlist is not None:
@@ -211,25 +211,7 @@ class OneToManyDP(DependencyProcessor):
         if delete:
             # head object is being deleted, and we manage its list of child objects
             # the child objects have to have their foreign key to the parent set to NULL
-            if self.post_update:
-                pass
-            # TODO: this block based on "delete_orphan" should technically be "delete", but also
-            # is entirely not necessary
-            elif self.cascade.delete_orphan:
-                for obj in deplist:
-                    childlist = self.get_object_dependencies(obj, uowcommit, passive=self.passive_deletes)
-                    if childlist is not None:
-                        for child in childlist.deleted_items():
-                            if child is not None and childlist.hasparent(child) is False:
-                                uowcommit.register_object(child, isdelete=True)
-                                for c in self.mapper.cascade_iterator('delete', child):
-                                    uowcommit.register_object(c, isdelete=True)
-                        for child in childlist.unchanged_items():
-                            if child is not None:
-                                uowcommit.register_object(child, isdelete=True)
-                                for c in self.mapper.cascade_iterator('delete', child):
-                                    uowcommit.register_object(c, isdelete=True)
-            else:
+            if not self.post_update and not self.cascade.delete:
                 for obj in deplist:
                     childlist = self.get_object_dependencies(obj, uowcommit, passive=self.passive_deletes)
                     if childlist is not None:
diff --git a/lib/sqlalchemy/orm/unitofwork.py b/lib/sqlalchemy/orm/unitofwork.py
index 732970cad..c6b0b2689 100644
--- a/lib/sqlalchemy/orm/unitofwork.py
+++ b/lib/sqlalchemy/orm/unitofwork.py
@@ -192,25 +192,16 @@ class UnitOfWork(object):
         # store objects whose fate has been decided
         processed = util.Set()
 
-
-        # put all saves/updates into the flush context.  detect orphans and throw them into deleted.
+        # put all saves/updates into the flush context.  detect top-level orphans and throw them into deleted.
         for obj in self.new.union(dirty).intersection(objset).difference(self.deleted):
             if obj in processed:
                 continue
-            if object_mapper(obj)._is_orphan(obj):
-                for c in [obj] + list(object_mapper(obj).cascade_iterator('delete', obj)):
-                    if c in processed:
-                        continue
-                    flush_context.register_object(c, isdelete=True)
-                    processed.add(c)
-            else:
-                flush_context.register_object(obj)
-                processed.add(obj)
+
+            flush_context.register_object(obj, isdelete=object_mapper(obj)._is_orphan(obj))
+            processed.add(obj)
 
         # put all remaining deletes into the flush context.
-        for obj in self.deleted:
-            if (objset is not None and not obj in objset) or obj in processed:
-                continue
+        for obj in self.deleted.intersection(objset).difference(processed):
             flush_context.register_object(obj, isdelete=True)
 
         trans = session.create_transaction(autoflush=False)