- Removal of event listeners is now implemented. The feature is

provided via the :func:`.event.remove` function.
[ticket:2268]
- reorganization of event.py module into a package; with the addition of the
docstring work as well as the new registry for removal, there's a lot more code now.
the package separates concerns and provides a top-level doc for each subsection
of functionality
- the remove feature works by providing the EventKey object which associates
the user-provided arguments to listen() with a global, weak-referencing registry.
This registry stores a collection of _ListenerCollection and _DispatchDescriptor
objects associated with each set of arguments, as well as the wrapped function
which was applied to that collection.  The EventKey can then be recreated for
a removal, all the _ListenerCollection and _DispatchDescriptor objects are located,
and the correct wrapped function is removed from each one.

1 files changed, 6 insertions, 0 deletions

diff --git a/lib/sqlalchemy/orm/instrumentation.py b/lib/sqlalchemy/orm/instrumentation.py
index 368a6a0b1..877a72193 100644
--- a/lib/sqlalchemy/orm/instrumentation.py
+++ b/lib/sqlalchemy/orm/instrumentation.py
@@ -81,6 +81,12 @@ class ClassManager(dict):
 
     dispatch = event.dispatcher(events.InstanceEvents)
 
+    def __hash__(self):
+        return id(self)
+
+    def __eq__(self, other):
+        return other is self
+
     @property
     def is_mapped(self):
         return 'mapper' in self.__dict__