Add sys._is_immortal

Author: ZeroIntensity

Lib/test/test_sys.py

@@ -713,6 +713,20 @@ def test_43581(self):
         # the test runs under regrtest.
         self.assertEqual(sys.__stdout__.encoding, sys.__stderr__.encoding)
 
+    @unittest.skipUnless(hasattr(sys, "_is_immortal"))
+    def test_immortal(self):
+        # Not extensive
+        known_immortals = (True, False, None, 0, ())
+        for immortal in known_immortals:
+            with self.subTest(immortal=immortal):
+                self.assertTrue(sys._is_immortal(immortal))
+
+        # Some arbitrary mutable objects
+        non_immortals = (object(), self, [object()])
+        for non_immortal in non_immortals:
+            with self.subTest(non_immortal=non_immortal):
+                self.assertFalse(sys._is_immortal(non_immortal))
+
     def test_intern(self):
         has_is_interned = (test.support.check_impl_detail(cpython=True)
                            or hasattr(sys, '_is_interned'))

Python/clinic/sysmodule.c.h

@@ -955,6 +955,21 @@ sys_intern_impl(PyObject *module, PyObject *s)
     }
 }
 
+/*[clinic input]
+sys._is_immortal -> bool
+
+  op: object
+  /
+
+Return True if the given object is "immortal" per PEP 683.
+[clinic start generated code]*/
+
+static int
+sys__is_immortal_impl(PyObject *module, PyObject *op)
+/*[clinic end generated code: output=c2f5d6a80efb8d1a input=83733fc356c78475]*/
+{
+    return _Py_IsImmortal(op);
+}
 
 /*[clinic input]
 sys._is_interned -> bool
@@ -2590,6 +2605,7 @@ static PyMethodDef sys_methods[] = {
     SYS__GETFRAMEMODULENAME_METHODDEF
     SYS_GETWINDOWSVERSION_METHODDEF
     SYS__ENABLELEGACYWINDOWSFSENCODING_METHODDEF
+    SYS__IS_IMMORTAL_METHODDEF
     SYS_INTERN_METHODDEF
     SYS__IS_INTERNED_METHODDEF
     SYS_IS_FINALIZING_METHODDEF