Issue #14195: Make WeakSet.__lt__ and WeakSet.__gt__ irreflexive.

Lib/_weakrefset.py

@@ -154,17 +154,17 @@ class WeakSet(object):
 
     def issubset(self, other):
         return self.data.issubset(ref(item) for item in other)
-    __lt__ = issubset
+    __le__ = issubset
 
-    def __le__(self, other):
-        return self.data <= set(ref(item) for item in other)
+    def __lt__(self, other):
+        return self.data < set(ref(item) for item in other)
 
     def issuperset(self, other):
         return self.data.issuperset(ref(item) for item in other)
-    __gt__ = issuperset
+    __ge__ = issuperset
 
-    def __ge__(self, other):
-        return self.data >= set(ref(item) for item in other)
+    def __gt__(self, other):
+        return self.data > set(ref(item) for item in other)
 
     def __eq__(self, other):
         if not isinstance(other, self.__class__):

Lib/test/test_weakset.py

@@ -41,6 +41,12 @@ class TestWeakSet(unittest.TestCase):
         self.items = [SomeClass(c) for c in ('a', 'b', 'c')]
         self.items2 = [SomeClass(c) for c in ('x', 'y', 'z')]
         self.letters = [SomeClass(c) for c in string.ascii_letters]
+        self.ab_items = [SomeClass(c) for c in 'ab']
+        self.abcde_items = [SomeClass(c) for c in 'abcde']
+        self.def_items = [SomeClass(c) for c in 'def']
+        self.ab_weakset = WeakSet(self.ab_items)
+        self.abcde_weakset = WeakSet(self.abcde_items)
+        self.def_weakset = WeakSet(self.def_items)
         self.s = WeakSet(self.items)
         self.d = dict.fromkeys(self.items)
         self.obj = SomeClass('F')
@@ -149,22 +155,28 @@ class TestWeakSet(unittest.TestCase):
         self.assertEqual(self.s ^ frozenset(self.items2), i)
 
     def test_sub_and_super(self):
-        pl, ql, rl = map(lambda s: [SomeClass(c) for c in s], ['ab', 'abcde', 'def'])
-        p, q, r = map(WeakSet, (pl, ql, rl))
-        self.assertTrue(p < q)
-        self.assertTrue(p <= q)
-        self.assertTrue(q <= q)
-        self.assertTrue(q > p)
-        self.assertTrue(q >= p)
-        self.assertFalse(q < r)
-        self.assertFalse(q <= r)
-        self.assertFalse(q > r)
-        self.assertFalse(q >= r)
+        self.assertTrue(self.ab_weakset <= self.abcde_weakset)
+        self.assertTrue(self.abcde_weakset <= self.abcde_weakset)
+        self.assertTrue(self.abcde_weakset >= self.ab_weakset)
+        self.assertFalse(self.abcde_weakset <= self.def_weakset)
+        self.assertFalse(self.abcde_weakset >= self.def_weakset)
         self.assertTrue(set('a').issubset('abc'))
         self.assertTrue(set('abc').issuperset('a'))
         self.assertFalse(set('a').issubset('cbs'))
         self.assertFalse(set('cbs').issuperset('a'))
 
+    def test_lt(self):
+        self.assertTrue(self.ab_weakset < self.abcde_weakset)
+        self.assertFalse(self.abcde_weakset < self.def_weakset)
+        self.assertFalse(self.ab_weakset < self.ab_weakset)
+        self.assertFalse(WeakSet() < WeakSet())
+
+    def test_gt(self):
+        self.assertTrue(self.abcde_weakset > self.ab_weakset)
+        self.assertFalse(self.abcde_weakset > self.def_weakset)
+        self.assertFalse(self.ab_weakset > self.ab_weakset)
+        self.assertFalse(WeakSet() > WeakSet())
+
     def test_gc(self):
         # Create a nest of cycles to exercise overall ref count check
         s = WeakSet(Foo() for i in range(1000))

Misc/NEWS

@@ -101,6 +101,10 @@ Core and Builtins
 Library
 -------
 
+- Issue #14195: An issue that caused weakref.WeakSet instances to incorrectly
+  return True for a WeakSet instance 'a' in both 'a < a' and 'a > a' has been
+  fixed.
+
 - Issue #14159: Fix the len() of weak sets to return a better approximation
   when some objects are dead or dying.  Moreover, the implementation is now
   O(1) rather than O(n).