Revert "[3.11] pythongh-46376: Return existing pointer when possible …

…in ctypes (pythonGH-107131) (python#107488)"

This reverts commit 57f27e4.

Lib/ctypes/test/test_keeprefs.py

@@ -93,33 +93,6 @@ def test_p_cint(self):
  x = pointer(i)
  self.assertEqual(x._objects, {'1': i})
 
- def test_pp_ownership(self):
- d = c_int(123)
- n = c_int(456)
-
- p = pointer(d)
- pp = pointer(p)
-
- self.assertIs(pp._objects['1'], p)
- self.assertIs(pp._objects['0']['1'], d)
-
- pp.contents.contents = n
-
- self.assertIs(pp._objects['1'], p)
- self.assertIs(pp._objects['0']['1'], n)
-
- self.assertIs(p._objects['1'], n)
- self.assertEqual(len(p._objects), 1)
-
- del d
- del p
-
- self.assertIs(pp._objects['0']['1'], n)
- self.assertEqual(len(pp._objects), 2)
-
- del n
-
- self.assertEqual(len(pp._objects), 2)
 
 class PointerToStructure(unittest.TestCase):
  def test(self):

Modules/_ctypes/_ctypes.c

@@ -5158,8 +5158,6 @@ static PyObject *
 Pointer_get_contents(CDataObject *self, void *closure)
 {
  StgDictObject *stgdict;
- PyObject *keep, *ptr_probe;
- CDataObject *ptr2ptr;
 
  if (*(void **)self->b_ptr == NULL) {
  PyErr_SetString(PyExc_ValueError,
@@ -5169,33 +5167,6 @@ Pointer_get_contents(CDataObject *self, void *closure)
 
  stgdict = PyObject_stgdict((PyObject *)self);
  assert(stgdict); /* Cannot be NULL for pointer instances */
-
- keep = GetKeepedObjects(self);
- if (keep != NULL) {
- // check if it's a pointer to a pointer:
- // pointers will have '0' key in the _objects
- ptr_probe = PyDict_GetItemString(keep, "0");
-
- if (ptr_probe != NULL) {
- ptr2ptr = (CDataObject*) PyDict_GetItemString(keep, "1");
- if (ptr2ptr == NULL) {
- PyErr_SetString(PyExc_ValueError,
- "Unexpected NULL pointer in _objects");
- return NULL;
- }
- // don't construct a new object,
- // return existing one instead to preserve refcount
- assert(
- *(void**) self->b_ptr == ptr2ptr->b_ptr ||
- *(void**) self->b_value.c == ptr2ptr->b_ptr ||
- *(void**) self->b_ptr == ptr2ptr->b_value.c ||
- *(void**) self->b_value.c == ptr2ptr->b_value.c
- ); // double-check that we are returning the same thing
- Py_INCREF(ptr2ptr);
- return (PyObject *) ptr2ptr;
- }
- }
-
  return PyCData_FromBaseObj(stgdict->proto,
  (PyObject *)self, 0,
  *(void **)self->b_ptr);