Closes #15514: Correct __sizeof__ support for cpu_set

Lib/test/test_posix.py

@@ -1008,6 +1008,12 @@ class PosixTester(unittest.TestCase):
         self.assertIs(b, l)
         self.assertEqual(l.count(), 3)
 
+    @requires_sched_affinity
+    @support.cpython_only
+    def test_cpu_set_sizeof(self):
+        self.assertGreater(sys.getsizeof(posix.cpu_set(1000)),
+                           sys.getsizeof(posix.cpu_set(1)))
+
     def test_rtld_constants(self):
         # check presence of major RTLD_* constants
         posix.RTLD_LAZY

Misc/NEWS

@@ -373,6 +373,9 @@ Library
 - Issue #15487: Add a __sizeof__ implementation for buffered I/O objects.
   Patch by Serhiy Storchaka.
 
+- Issue #15514: Correct __sizeof__ support for cpu_set.
+  Patch by Serhiy Storchaka.
+
 - Issue #15187: Bugfix: remove temporary directories test_shutil was leaving
   behind.
 

Modules/posixmodule.c

@@ -5772,6 +5772,20 @@ cpu_set_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
     return (PyObject *)make_new_cpu_set(type, size);
 }
 
+PyDoc_STRVAR(cpu_set_sizeof_doc,
+"cpu_set.__sizeof__() -> int\n\n\
+Returns size in memory, in bytes.");
+
+static PyObject *
+cpu_set_sizeof(Py_cpu_set *set, PyObject *noargs)
+{
+    Py_ssize_t res = 0;
+
+    res = sizeof(Py_cpu_set);
+    res += set->size;
+    return PyLong_FromSsize_t(res);
+}
+
 static PyObject *
 cpu_set_repr(Py_cpu_set *set)
 {
@@ -5959,6 +5973,7 @@ static PyMethodDef cpu_set_methods[] = {
     {"isset", (PyCFunction)cpu_set_isset, METH_VARARGS, cpu_set_isset_doc},
     {"set", (PyCFunction)cpu_set_set, METH_VARARGS, cpu_set_set_doc},
     {"zero", (PyCFunction)cpu_set_zero, METH_NOARGS, cpu_set_zero_doc},
+    {"__sizeof__", (PyCFunction)cpu_set_sizeof, METH_NOARGS, cpu_set_sizeof_doc},
     {NULL, NULL}   /* sentinel */
 };