Fix equality testing of implementedBy objects that have been proxied. Fixes #55.fix-55

1 files changed, 6 insertions, 5 deletions

diff --git a/src/zope/interface/declarations.py b/src/zope/interface/declarations.py
index d770fa0..48e459a 100644
--- a/src/zope/interface/declarations.py
+++ b/src/zope/interface/declarations.py
@@ -176,11 +176,12 @@ class Implements(Declaration):
     def __hash__(self):
         return Declaration.__hash__(self)
 
-    def __eq__(self, other):
-        return self is other
-
-    def __ne__(self, other):
-        return self is not other
+    # We want equality to be based on identity. However, we can't actually
+    # implement __eq__/__ne__ to do this because sometimes we get wrapped in a proxy.
+    # We need to let the proxy types implement these methods so they can handle unwrapping
+    # and then rely on: (1) the interpreter automatically changing `implements == proxy` into
+    # `proxy == implements` (which will call proxy.__eq__ to do the unwrapping) and then
+    # (2) the default equality semantics being identity based.
 
     def __lt__(self, other):
         c = self.__cmp(other)