Fixed bug https://bugs.launchpad.net/zope3/+bug/109980.

The registry code should always use identity tests to test whether an
object is already in the registry so as not to run afoul of custom
comparison methods.

2 files changed, 25 insertions, 3 deletions

diff --git a/src/zope/interface/adapter.py b/src/zope/interface/adapter.py
index 3794b0e..a8dd335 100644
--- a/src/zope/interface/adapter.py
+++ b/src/zope/interface/adapter.py
@@ -106,7 +106,7 @@ class BaseAdapterRegistry(object):
                 components[k] = d
             components = d
 
-        if components.get(name) == value:
+        if components.get(name) is value:
             return
         
         components[name] = value
@@ -155,7 +155,7 @@ class BaseAdapterRegistry(object):
         old = components.get(name)
         if old is None:
             return
-        if (value is not None) and (old != value):
+        if (value is not None) and (old is not value):
             return
 
         del components[name]
@@ -220,7 +220,7 @@ class BaseAdapterRegistry(object):
         if value is None:
             new = ()
         else:
-            new = tuple([v for v in old if v != value])
+            new = tuple([v for v in old if v is not value])
 
         if new == old:
             return
diff --git a/src/zope/interface/tests/test_adapter.py b/src/zope/interface/tests/test_adapter.py
index cc8ebd2..33fb5e1 100644
--- a/src/zope/interface/tests/test_adapter.py
+++ b/src/zope/interface/tests/test_adapter.py
@@ -321,6 +321,28 @@ There was a bug that caused problems if a spec had multiple bases:
     'Y'
 """
 
+def test_register_objects_with_cmp():
+    """
+    The registry should never use == as that will tend to fail when
+    objects are picky about what they are compared with:
+
+    >>> class Picky:
+    ...     def __cmp__(self, other):
+    ...         raise TypeError("I\'m too picky for comparison!")
+    >>> class I(zope.interface.Interface):
+    ...     pass
+    >>> class I2(I, I):
+    ...     pass
+
+    >>> registry = AdapterRegistry()
+    >>> picky = Picky()
+    >>> registry.register([I2], IR0, '', picky)
+    >>> registry.unregister([I2], IR0, '', picky)
+
+    >>> registry.subscribe([I2], IR0, picky)
+    >>> registry.unsubscribe([I2], IR0, picky)
+
+    """
 
 def test_suite():
     from zope.testing import doctest, doctestunit