Allow Registering and unregistering instance methods as listeners (#102)

* Fixes #12 - registering instance methods as listeners doesn’t allow to easily unregister them as the registry tries to find the handler with 'is' but it should use '==' to allow the python BoundMethod wrapper (which is a new instance every time instance.$methodname is accessed).

2 files changed, 12 insertions, 1 deletions

diff --git a/src/zope/interface/adapter.py b/src/zope/interface/adapter.py
index d4825b2..aae3155 100644
--- a/src/zope/interface/adapter.py
+++ b/src/zope/interface/adapter.py
@@ -257,7 +257,7 @@ class BaseAdapterRegistry(object):
         if value is None:
             new = ()
         else:
-            new = tuple([v for v in old if v is not value])
+            new = tuple([v for v in old if v != value])
 
         if new == old:
             return
diff --git a/src/zope/interface/tests/test_adapter.py b/src/zope/interface/tests/test_adapter.py
index 7420e1c..41c618c 100644
--- a/src/zope/interface/tests/test_adapter.py
+++ b/src/zope/interface/tests/test_adapter.py
@@ -234,6 +234,17 @@ class BaseAdapterRegistryTests(unittest.TestCase):
         registry.subscribe([IB1], None, orig)
         registry.unsubscribe([IB1], None, nomatch) #doesn't raise
         self.assertEqual(len(registry._subscribers), 2)
+    
+    def _instance_method_notify_target(self):
+        self.fail("Example method, not intended to be called.")
+    
+    def test_unsubscribe_instance_method(self):
+        IB0, IB1, IB2, IB3, IB4, IF0, IF1, IR0, IR1 = _makeInterfaces()
+        registry = self._makeOne()
+        self.assertEqual(len(registry._subscribers), 0)
+        registry.subscribe([IB1], None, self._instance_method_notify_target)
+        registry.unsubscribe([IB1], None, self._instance_method_notify_target)
+        self.assertEqual(len(registry._subscribers), 0)
 
 
 class LookupBaseFallbackTests(unittest.TestCase):