Correct comparison of interfaces from different modules but with the same name.

Fixes LP #570942.

1 files changed, 19 insertions, 9 deletions

diff --git a/src/zope/interface/interface.py b/src/zope/interface/interface.py
index a2bd3ae..ed6366d 100644
--- a/src/zope/interface/interface.py
+++ b/src/zope/interface/interface.py
@@ -670,31 +670,41 @@ class InterfaceClass(Element, InterfaceBase, Specification):
         sort before None.
 
         """
-        if o1 == o2:
-            return 0
-
         if o1 is None:
             return 1
         if o2 is None:
             return -1
 
-        n1 = (getattr(o1, '__name__', ''),
-              getattr(getattr(o1,  '__module__', None), '__name__', ''))
-        n2 = (getattr(o2, '__name__', ''),
-              getattr(getattr(o2,  '__module__', None), '__name__', ''))
+        n1 = (getattr(o1, '__name__', ''), getattr(o1,  '__module__', ''))
+        n2 = (getattr(o2, '__name__', ''), getattr(o2,  '__module__', ''))
 
+        # This spelling works under Python3, which doesn't have cmp().
         return (n1 > n2) - (n1 < n2)
 
+    def __eq__(self, other):
+        c = self.__cmp(self, other)
+        return c == 0
+
+    def __ne__(self, other):
+        c = self.__cmp(self, other)
+        return c != 0
+
     def __lt__(self, other):
         c = self.__cmp(self, other)
-        #print '<', self, other, c < 0, c
         return c < 0
 
+    def __le__(self, other):
+        c = self.__cmp(self, other)
+        return c <= 0
+
     def __gt__(self, other):
         c = self.__cmp(self, other)
-        #print '>', self, other, c > 0, c
         return c > 0
 
+    def __ge__(self, other):
+        c = self.__cmp(self, other)
+        return c >= 0
+
 
 Interface = InterfaceClass("Interface", __module__ = 'zope.interface')