Change the repr() of frozenset instances (and set subclasses)

from name([e1, e2, ...]) to name({e1, e2, ...}).
This makes more sense now we have the set notation.

Lib/test/test_set.py

@@ -265,7 +265,7 @@ class TestJointOps(unittest.TestCase):
             self.assertEqual(repr(s), '{set(...)}')
         else:
             name = repr(s).partition('(')[0]    # strip class name
-            self.assertEqual(repr(s), '%s([%s(...)])' % (name, name))
+            self.assertEqual(repr(s), '%s({%s(...)})' % (name, name))
 
     def test_cyclical_print(self):
         w = ReprWrapper()

Objects/setobject.c

@@ -571,6 +571,8 @@ set_repr(PySetObject *so)
 	PyObject *keys, *result=NULL;
 	Py_UNICODE *u;
 	int status = Py_ReprEnter((PyObject*)so);
+	PyObject *listrepr;
+	Py_ssize_t newsize;
 
 	if (status != 0) {
 		if (status < 0)
@@ -588,13 +590,7 @@ set_repr(PySetObject *so)
 	if (keys == NULL)
 		goto done;
 
-	if (Py_Type(so) != &PySet_Type) {
-		result = PyUnicode_FromFormat("%s(%R)", Py_Type(so)->tp_name, keys);
-		Py_DECREF(keys);
-	}
-	else {
-		PyObject *listrepr = PyObject_Repr(keys);
-		Py_ssize_t newsize;
+	listrepr = PyObject_Repr(keys);
 	Py_DECREF(keys);
 	if (listrepr == NULL) {
 		Py_DECREF(keys);
@@ -612,6 +608,12 @@ set_repr(PySetObject *so)
 		*u++ = '}';
 	}
 	Py_DECREF(listrepr);
+	if (Py_Type(so) != &PySet_Type) {
+		PyObject *tmp = PyUnicode_FromFormat("%s(%U)",
+						     Py_Type(so)->tp_name,
+						     result);
+		Py_DECREF(result);
+		result = tmp;
 	}
 done:
 	Py_ReprLeave((PyObject*)so);