Extend temporary hashability to remove() and discard().

Brings the functionality back in line with sets.py.

Lib/test/test_set.py

@@ -182,12 +182,22 @@ class TestSet(TestJointOps):
         self.assert_('a' not in self.s)
         self.assertRaises(KeyError, self.s.remove, 'Q')
         self.assertRaises(TypeError, self.s.remove, [])
+        s = self.thetype([frozenset(self.word)])
+        self.assert_(self.thetype(self.word) in s)
+        s.remove(self.thetype(self.word))
+        self.assert_(self.thetype(self.word) not in s)
+        self.assertRaises(KeyError, self.s.remove, self.thetype(self.word))
 
     def test_discard(self):
         self.s.discard('a')
         self.assert_('a' not in self.s)
         self.s.discard('Q')
         self.assertRaises(TypeError, self.s.discard, [])
+        s = self.thetype([frozenset(self.word)])
+        self.assert_(self.thetype(self.word) in s)
+        s.discard(self.thetype(self.word))
+        self.assert_(self.thetype(self.word) not in s)
+        s.discard(self.thetype(self.word))
 
     def test_pop(self):
         for i in xrange(len(self.s)):

Objects/setobject.c

@@ -73,6 +73,21 @@ set_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
 	return make_new_set(type, NULL);
 }
 
+static PyObject *
+frozenset_dict_wrapper(PyObject *d)
+{
+	PySetObject *w;
+
+	assert(PyDict_Check(d));
+	w = (PySetObject *)make_new_set(&PyFrozenSet_Type, NULL);
+	if (w == NULL)
+		return NULL;
+	Py_DECREF(w->data);
+	Py_INCREF(d);
+	w->data = d;
+	return (PyObject *)w;
+}
+
 static void
 set_dealloc(PySetObject *so)
 {
@@ -104,20 +119,16 @@ set_len(PySetObject *so)
 static int
 set_contains(PySetObject *so, PyObject *key)
 {
-	PyObject *olddict;
-	PySetObject *tmp;
+	PyObject *tmp;
 	int result;
 
 	result = PySequence_Contains(so->data, key);
 	if (result == -1 && PyType_IsSubtype(key->ob_type, &PySet_Type)) {
 		PyErr_Clear();
-		tmp = (PySetObject *)make_new_set(&PyFrozenSet_Type, NULL);
+		tmp = frozenset_dict_wrapper(((PySetObject *)(key))->data);
 		if (tmp == NULL)
 			return -1;
-		olddict = tmp->data;
-		tmp->data = ((PySetObject *)(key))->data;
-		result = PySequence_Contains(so->data, (PyObject *)tmp);
-		tmp->data = olddict;
+		result = PySequence_Contains(so->data, tmp);
 		Py_DECREF(tmp);
 	}
 	return result;
@@ -820,8 +831,21 @@ This has no effect if the element is already present.");
 static PyObject *
 set_remove(PySetObject *so, PyObject *item)
 {
-	if (PyDict_DelItem(so->data, item) == -1)
-		return NULL;
+	PyObject *tmp;
+
+	if (PyDict_DelItem(so->data, item) == -1) {
+		if (!PyType_IsSubtype(item->ob_type, &PySet_Type)) 
+			return NULL;
+		PyErr_Clear();
+		tmp = frozenset_dict_wrapper(((PySetObject *)(item))->data);
+		if (tmp == NULL)
+			return NULL;
+		if (PyDict_DelItem(so->data, tmp) == -1) {
+			Py_DECREF(tmp);
+			return NULL;
+		}
+		Py_DECREF(tmp);
+	}
 	Py_INCREF(Py_None);
 	return Py_None;
 }
@@ -834,11 +858,28 @@ If the element is not a member, raise a KeyError.");
 static PyObject *
 set_discard(PySetObject *so, PyObject *item)
 {
+	PyObject *tmp;
+
 	if (PyDict_DelItem(so->data, item) == -1) {
 		if  (PyErr_ExceptionMatches(PyExc_KeyError))
 			PyErr_Clear();
-		else
-			return NULL;
+		else {
+			if (!PyType_IsSubtype(item->ob_type, &PySet_Type)) 
+				return NULL;
+			PyErr_Clear();
+			tmp = frozenset_dict_wrapper(((PySetObject *)(item))->data);
+			if (tmp == NULL)
+				return NULL;
+			if (PyDict_DelItem(so->data, tmp) == -1) {
+				if  (PyErr_ExceptionMatches(PyExc_KeyError))
+					PyErr_Clear();
+				else {
+					Py_DECREF(tmp);
+					return NULL;
+				}
+			}
+			Py_DECREF(tmp);
+		}
 	}
 	Py_INCREF(Py_None);
 	return Py_None;