bpo-1617161: Make the hash and equality of methods not depending on the value of self. (GH-7848)

* The hash of BuiltinMethodType instances no longer depends on the hash
  of __self__. It depends now on the hash of id(__self__).
* The hash and equality of ModuleType and MethodWrapperType instances no
  longer depend on the hash and equality of __self__. They depend now on
  the hash and equality of id(__self__).
* MethodWrapperType instances no longer support ordering.

1 files changed, 4 insertions, 10 deletions

diff --git a/Objects/classobject.c b/Objects/classobject.c
index 095b0cad2b5..a193ada6d44 100644
--- a/Objects/classobject.c
+++ b/Objects/classobject.c
@@ -225,13 +225,9 @@ method_richcompare(PyObject *self, PyObject *other, int op)
     b = (PyMethodObject *)other;
     eq = PyObject_RichCompareBool(a->im_func, b->im_func, Py_EQ);
     if (eq == 1) {
-        if (a->im_self == NULL || b->im_self == NULL)
-            eq = a->im_self == b->im_self;
-        else
-            eq = PyObject_RichCompareBool(a->im_self, b->im_self,
-                                          Py_EQ);
+        eq = (a->im_self == b->im_self);
     }
-    if (eq < 0)
+    else if (eq < 0)
         return NULL;
     if (op == Py_EQ)
         res = eq ? Py_True : Py_False;
@@ -274,11 +270,9 @@ method_hash(PyMethodObject *a)
 {
     Py_hash_t x, y;
     if (a->im_self == NULL)
-        x = PyObject_Hash(Py_None);
+        x = _Py_HashPointer(Py_None);
     else
-        x = PyObject_Hash(a->im_self);
-    if (x == -1)
-        return -1;
+        x = _Py_HashPointer(a->im_self);
     y = PyObject_Hash(a->im_func);
     if (y == -1)
         return -1;