gh-134819: Add sys.set_object_tags and sys.get_object_tags

Lib/test/test_sys.py

@@ -753,23 +753,25 @@ def test_43581(self):
         self.assertEqual(sys.__stdout__.encoding, sys.__stderr__.encoding)
 
     def test_intern(self):
-        has_is_interned = (test.support.check_impl_detail(cpython=True)
-                           or hasattr(sys, '_is_interned'))
         self.assertRaises(TypeError, sys.intern)
         self.assertRaises(TypeError, sys.intern, b'abc')
+        has_is_interned = (test.support.check_impl_detail(cpython=True)
+                           or hasattr(sys, '_is_interned'))
         if has_is_interned:
             self.assertRaises(TypeError, sys._is_interned)
             self.assertRaises(TypeError, sys._is_interned, b'abc')
+
+        def _is_interned(obj):
+            tags = sys.get_object_tags(obj)
+            return tags.get("interned", False)
+
         s = "never interned before" + str(random.randrange(0, 10**9))
         self.assertTrue(sys.intern(s) is s)
-        if has_is_interned:
-            self.assertIs(sys._is_interned(s), True)
+        self.assertIs(_is_interned(s), True)
         s2 = s.swapcase().swapcase()
-        if has_is_interned:
-            self.assertIs(sys._is_interned(s2), False)
+        self.assertIs(_is_interned(s2), False)
         self.assertTrue(sys.intern(s2) is s)
-        if has_is_interned:
-            self.assertIs(sys._is_interned(s2), False)
+        self.assertIs(_is_interned(s2), False)
 
         # Subclasses of string can't be interned, because they
         # provide too much opportunity for insane things to happen.
@@ -781,8 +783,31 @@ def __hash__(self):
                 return 123
 
         self.assertRaises(TypeError, sys.intern, S("abc"))
-        if has_is_interned:
-            self.assertIs(sys._is_interned(S("abc")), False)
+        self.assertIs(_is_interned(S("abc")), False)
+
+    @support.cpython_only
+    def test_get_object_tags(self):
+        keys = ("immortal", "interned", "deferred_refcount")
+        s = "foobar"
+        tags = sys.get_object_tags(s)
+        self.assertEqual(len(tags), len(keys))
+        for k in keys:
+            self.assertIn(k, tags)
+
+    @support.cpython_only
+    def test_set_object_tags(self):
+        keys = ("immortal", "interned")
+        s = "should never interned before" + str(random.randrange(0, 10**9))
+        origin_tags = sys.get_object_tags(s)
+        for k in keys:
+            self.assertFalse(origin_tags[k])
+            sys.set_object_tag(s, k)
+        sys.set_object_tag(s, "unknown")
+        after_tags = sys.get_object_tags(s)
+        self.assertEqual(len(origin_tags), len(after_tags))
+        for k in keys:
+            self.assertIn(k, after_tags)
+            self.assertTrue(after_tags[k])
 
     @support.cpython_only
     @requires_subinterpreters
@@ -847,7 +872,8 @@ def test_subinterp_intern_singleton(self):
                     assert id(s) == {id(s)}
                     t = sys.intern(s)
                     '''))
-                self.assertTrue(sys._is_interned(s))
+                tags = sys.get_object_tags(s)
+                self.assertTrue(tags.get("interned", False))
 
     def test_sys_flags(self):
         self.assertTrue(sys.flags)

Misc/NEWS.d/next/Core_and_Builtins/2025-06-03-21-55-03.gh-issue-134819.M9PZZc.rst

@@ -0,0 +1,2 @@
+Add :func:`sys.get_object_tags` and :func:`sys.set_object_tags` for handling
+CPython object implementation detail. Patch By Donghee Na.

Python/sysmodule.c

@@ -1052,6 +1052,91 @@ sys__is_immortal_impl(PyObject *module, PyObject *op)
     return PyUnstable_IsImmortal(op);
 }
 
+
+/*[clinic input]
+sys.get_object_tags -> object
+
+  op: object
+  /
+Return the tags of the given object.
+[clinic start generated code]*/
+
+static PyObject *
+sys_get_object_tags(PyObject *module, PyObject *op)
+/*[clinic end generated code: output=a68da7f1805c9216 input=75993fb67096e2ff]*/
+{
+    assert(op != NULL);
+    PyObject *dict = PyDict_New();
+    if (dict == NULL) {
+        return NULL;
+    }
+    if (PyUnstable_IsImmortal(op)) {
+        if (PyDict_SetItemString(dict, "immortal", Py_True) < 0) {
+            Py_DECREF(dict);
+            return NULL;
+        }
+    }
+    else {
+        if (PyDict_SetItemString(dict, "immortal", Py_False) < 0) {
+            Py_DECREF(dict);
+            return NULL;
+        }
+    }
+
+    if (PyUnicode_Check(op) && PyUnicode_CHECK_INTERNED(op)) {
+        if (PyDict_SetItemString(dict, "interned", Py_True) < 0) {
+            Py_DECREF(dict);
+            return NULL;
+        }
+    }
+    else {
+        if (PyDict_SetItemString(dict, "interned", Py_False) < 0) {
+            Py_DECREF(dict);
+            return NULL;
+        }
+    }
+
+    if (PyUnstable_Object_EnableDeferredRefcount(op)) {
+        if (PyDict_SetItemString(dict, "deferred_refcount", Py_True) < 0) {
+            Py_DECREF(dict);
+            return NULL;
+        }
+    }
+    else {
+        if (PyDict_SetItemString(dict, "deferred_refcount", Py_False) < 0) {
+            Py_DECREF(dict);
+            return NULL;
+        }
+    }
+    return dict;
+}
+
+/*[clinic input]
+sys.set_object_tag -> object
+
+  object: object
+  tag: str
+  *
+  options: object = None
+
+Set the tags of the given object.
+[clinic start generated code]*/
+
+static PyObject *
+sys_set_object_tag_impl(PyObject *module, PyObject *object, const char *tag,
+                        PyObject *options)
+/*[clinic end generated code: output=b0fb5e9931feb4aa input=b64c9bd958c75f11]*/
+{
+    assert(object != NULL);
+    if (strcmp(tag, "immortal") == 0) {
+        _Py_SetImmortal(object);
+    }
+    else if (strcmp(tag, "interned") == 0) {
+        _PyUnicode_InternMortal(_PyInterpreterState_GET(), &object);
+    }
+    Py_RETURN_NONE;
+}
+
 /*
  * Cached interned string objects used for calling the profile and
  * trace functions.
@@ -2796,6 +2881,8 @@ static PyMethodDef sys_methods[] = {
     SYS__IS_IMMORTAL_METHODDEF
     SYS_INTERN_METHODDEF
     SYS__IS_INTERNED_METHODDEF
+    SYS_GET_OBJECT_TAGS_METHODDEF
+    SYS_SET_OBJECT_TAG_METHODDEF
     SYS_IS_FINALIZING_METHODDEF
     SYS_MDEBUG_METHODDEF
     SYS_SETSWITCHINTERVAL_METHODDEF