Remove support for hashing uninitialized interfaces.issue157

Fixes #157

4 files changed, 16 insertions, 20 deletions

diff --git a/CHANGES.rst b/CHANGES.rst
index 77fecbd..1d6923c 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -2,7 +2,7 @@
  Changes
 =========
 
-4.8.0 (unreleased)
+5.0.0 (unreleased)
 ==================
 
 - Support the ``PURE_PYTHON`` environment variable at runtime instead
@@ -33,11 +33,20 @@
   - Likewise, tagged values are relatively rare, so don't allocate a
     dictionary to hold them until they are used.
   - Use ``__slots___`` or the C equivalent ``tp_members`` in more
-    common places. See `PR 155 <https://github.com/zopefoundation/zope.interface/pull/155>`_.
+    common places. Note that this removes the ability to set arbitrary
+    instance variables on certain objects.
+    See `PR 155 <https://github.com/zopefoundation/zope.interface/pull/155>`_.
 
   The changes in this release resulted in a 7% memory reduction after
   loading about 6,000 modules that define about 2,200 interfaces.
 
+- Remove support for hashing uninitialized interfaces. This could only
+  be done by subclassing ``InterfaceClass``. This has generated a
+  warning since it was first added in 2011 (3.6.5). Please call the
+  ``InterfaceClass`` constructor or otherwise set the appropriate
+  fields in your subclass before attempting to hash or sort it. See
+  `issue 157 <https://github.com/zopefoundation/zope.interface/issues/157>`_.
+
 4.7.1 (2019-11-11)
 ==================
 
diff --git a/setup.py b/setup.py
index d6d0e34..b5e87a8 100644
--- a/setup.py
+++ b/setup.py
@@ -95,7 +95,7 @@ long_description = (
         )
 
 setup(name='zope.interface',
-      version='4.8.0.dev0',
+      version='5.0.0.dev0',
       url='https://github.com/zopefoundation/zope.interface',
       license='ZPL 2.1',
       description='Interfaces for Python',
diff --git a/src/zope/interface/interface.py b/src/zope/interface/interface.py
index 106a60d..7fa56aa 100644
--- a/src/zope/interface/interface.py
+++ b/src/zope/interface/interface.py
@@ -17,7 +17,6 @@
 import sys
 from types import MethodType
 from types import FunctionType
-import warnings
 import weakref
 
 from zope.interface._compat import _use_c_impl
@@ -579,7 +578,7 @@ class InterfaceClass(Element, InterfaceBase, Specification):
         if other is None:
             return -1
 
-        n1 = (getattr(self, '__name__', ''), getattr(self, '__module__', ''))
+        n1 = (self.__name__, self.__module__)
         n2 = (getattr(other, '__name__', ''), getattr(other, '__module__', ''))
 
         # This spelling works under Python3, which doesn't have cmp().
@@ -589,11 +588,7 @@ class InterfaceClass(Element, InterfaceBase, Specification):
         try:
             return self._v_cached_hash
         except AttributeError:
-            try:
-                self._v_cached_hash = hash((self.__name__, self.__module__))
-            except AttributeError: # pragma: no cover
-                warnings.warn('Hashing uninitialized InterfaceClass instance')
-                return 1
+            self._v_cached_hash = hash((self.__name__, self.__module__))
         return self._v_cached_hash
 
     def __eq__(self, other):
diff --git a/src/zope/interface/tests/test_interface.py b/src/zope/interface/tests/test_interface.py
index f5a57b4..3bf26dc 100644
--- a/src/zope/interface/tests/test_interface.py
+++ b/src/zope/interface/tests/test_interface.py
@@ -834,20 +834,12 @@ class InterfaceClassTests(unittest.TestCase):
                                 'zope.interface.tests.test_interface'))))
 
     def test___hash___missing_required_attrs(self):
-        import warnings
-        from warnings import catch_warnings
-
         class Derived(self._getTargetClass()):
             def __init__(self):
                 pass # Don't call base class.
         derived = Derived()
-        with catch_warnings(record=True) as warned:
-            warnings.simplefilter('always') # see LP #825249
-            self.assertEqual(hash(derived), 1)
-            self.assertEqual(len(warned), 1)
-            self.assertTrue(warned[0].category is UserWarning)
-            self.assertEqual(str(warned[0].message),
-                             'Hashing uninitialized InterfaceClass instance')
+        with self.assertRaises(AttributeError):
+            hash(derived)
 
     def test_comparison_with_None(self):
         iface = self._makeOne()