Work around buggy behavior in some subclasses of `InterfaceClass``

Some sublcasses invoke '__hash__' before initializing '__module__' and
'__name__'.  The workaround returns a fixed constant hash in such cases, and
issues a UserWarning.

Addresses LP #811792.

2 files changed, 55 insertions, 8 deletions

diff --git a/src/zope/interface/tests/ifoo_other.py b/src/zope/interface/tests/ifoo_other.py
new file mode 100644
index 0000000..29a7877
--- /dev/null
+++ b/src/zope/interface/tests/ifoo_other.py
@@ -0,0 +1,26 @@
+##############################################################################
+#
+# Copyright (c) 2001, 2002 Zope Foundation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE.
+#
+##############################################################################
+"""IFoo test module
+"""
+from zope.interface import Interface
+
+class IFoo(Interface):
+    """
+        Dummy interface for unit tests.
+    """
+
+    def bar(baz):
+        """
+            Just a note.
+        """
diff --git a/src/zope/interface/tests/test_interface.py b/src/zope/interface/tests/test_interface.py
index 034c8ec..2b8c8ce 100644
--- a/src/zope/interface/tests/test_interface.py
+++ b/src/zope/interface/tests/test_interface.py
@@ -387,14 +387,35 @@ class InterfaceTests(unittest.TestCase):
         self.failUnless(IEmpty >= IEmpty)
         self.failIf(IEmpty > IEmpty)
 
-    def test_hash(self):
-        from zope.interface import Interface
-
-        class IEmpty(Interface):
-            pass
-
-        self.assertEqual(hash(IEmpty),
-                         hash((IEmpty.__name__, IEmpty.__module__)))
+    def test_comparison_with_same_named_instance_in_other_module(self):
+        from zope.interface.tests.ifoo import IFoo as IFoo1
+        from zope.interface.tests.ifoo_other import IFoo as IFoo2
+
+        self.failUnless(IFoo1 < IFoo2)
+        self.failUnless(IFoo1 <= IFoo2)
+        self.failIf(IFoo1 == IFoo2)
+        self.failUnless(IFoo1 != IFoo2)
+        self.failIf(IFoo1 >= IFoo2)
+        self.failIf(IFoo1 > IFoo2)
+
+    def test_hash_normal(self):
+        from zope.interface.tests.ifoo import IFoo
+        self.assertEqual(hash(IFoo),
+                         hash((('IFoo', 'zope.interface.tests.ifoo'))))
+
+    def test_hash_missing_required_attrs(self):
+        from warnings import catch_warnings
+        from zope.interface.interface import InterfaceClass
+        class Derived(InterfaceClass):
+            def __init__(self):
+                pass # Don't call base class.
+        derived = Derived()
+        with catch_warnings(record=True) as warned:
+            self.assertEqual(hash(derived), 1)
+            self.assertEqual(len(warned), 1)
+            self.failUnless(warned[0].category is UserWarning)
+            self.assertEqual(str(warned[0].message),
+                             'Hashing uninitialized InterfaceClass instance')
 
 
 if sys.version_info >= (2, 4):