further work on insuring clear_mappers() really works. assignmapper identified

as a much trickier thing to clean out.  added a unit test so that if any new collections get introduced
we are still testing.

4 files changed, 16 insertions, 3 deletions

diff --git a/lib/sqlalchemy/ext/assignmapper.py b/lib/sqlalchemy/ext/assignmapper.py
index 89cf962e7..b76f29943 100644
--- a/lib/sqlalchemy/ext/assignmapper.py
+++ b/lib/sqlalchemy/ext/assignmapper.py
@@ -39,3 +39,4 @@ def assign_mapper(ctx, class_, *args, **kwargs):
     for name in ['flush', 'delete', 'expire', 'refresh', 'expunge', 'merge', 'save', 'update', 'save_or_update']:
         monkeypatch_objectstore_method(ctx, class_, name)
     return m
+
diff --git a/lib/sqlalchemy/orm/__init__.py b/lib/sqlalchemy/orm/__init__.py
index 96890272d..1e1a75b63 100644
--- a/lib/sqlalchemy/orm/__init__.py
+++ b/lib/sqlalchemy/orm/__init__.py
@@ -74,8 +74,10 @@ def clear_mappers():
     when new mappers are created, they will be assigned to their classes as their primary mapper."""
     for mapper in mapper_registry.values():
         attribute_manager.reset_class_managed(mapper.class_)
+        mapper.class_key.dispose()
+        if hasattr(mapper.class_, 'c'):
+            del mapper.class_.c
     mapper_registry.clear()
-    mapperlib.ClassKey.instances.clear()
     
 def clear_mapper(m):
     """remove the given mapper from the storage of mappers.  
@@ -83,7 +85,11 @@ def clear_mapper(m):
     when a new mapper is created for the previous mapper's class, it will be used as that classes' 
     new primary mapper."""
     del mapper_registry[m.class_key]
-
+    attribute_manager.reset_class_managed(m.class_)
+    if hasattr(m.class_, 'c'):
+        del m.class_.c
+    m.class_key.dispose()
+    
 def extension(ext):
     """return a MapperOption that will insert the given MapperExtension to the 
     beginning of the list of extensions that will be called in the context of the Query.
diff --git a/lib/sqlalchemy/orm/mapper.py b/lib/sqlalchemy/orm/mapper.py
index d6967934c..1d4ce6bb9 100644
--- a/lib/sqlalchemy/orm/mapper.py
+++ b/lib/sqlalchemy/orm/mapper.py
@@ -1458,7 +1458,9 @@ class ClassKey(object):
         return self is other
     def __repr__(self):
         return "ClassKey(%s, %s)" % (repr(self.class_), repr(self.entity_name))
-
+    def dispose(self):
+        type(self).dispose_static(self.class_, self.entity_name)
+        
 def has_identity(object):
     return hasattr(object, '_instance_key')
     
diff --git a/lib/sqlalchemy/util.py b/lib/sqlalchemy/util.py
index 706630918..54b1afa9f 100644
--- a/lib/sqlalchemy/util.py
+++ b/lib/sqlalchemy/util.py
@@ -49,6 +49,10 @@ def reversed(seq):
 
 class ArgSingleton(type):
     instances = {}
+    def dispose_static(self, *args):
+        hashkey = (self, args)
+        #if hashkey in ArgSingleton.instances:
+        del ArgSingleton.instances[hashkey]
     def __call__(self, *args):
         hashkey = (self, args)
         try: