8000 gh-121654: Add PyType_Freeze() function · vstinner/cpython@2d24aba · GitHub
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pythongh-121654: Add PyType_Freeze() function
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‎Doc/c-api/type.rst

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@@ -381,6 +381,17 @@ The following functions and structs are used to create
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:c:member:`~PyTypeObject.tp_new` is deprecated and in Python 3.14+ it
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will be no longer allowed.
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384+
.. c:function:: int PyType_Freeze(PyTypeObject *type)
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Make a type immutable: set the :c:macro:`Py_TPFLAGS_IMMUTABLETYPE` flag.
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Base classes must be immutable.
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On success, return ``0``.
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On error, set an exception and return ``-1``.
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.. versionadded:: 3.14
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.. raw:: html
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<!-- Keep old URL fragments working (see gh-97908) -->

‎Doc/data/stable_abi.dat

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‎Doc/whatsnew/3.14.rst

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@@ -472,6 +472,9 @@ New Features
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an interned string and deallocate it during module shutdown.
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(Contribued by Eddie Elizondo in :gh:`113601`.)
474474

475+
* Add :c:func:`PyType_Freeze` function to make a type immutable.
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(Contributed by Victor Stinner in :gh:`121654`.)
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Porting to Python 3.14
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----------------------
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‎Include/object.h

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@@ -786,6 +786,10 @@ static inline int PyType_CheckExact(PyObject *op) {
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PyAPI_FUNC(PyObject *) PyType_GetModuleByDef(PyTypeObject *, PyModuleDef *);
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#endif
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789+
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x030e0000
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PyAPI_FUNC(int) PyType_Freeze(PyTypeObject *type);
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#endif
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#ifdef __cplusplus
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}
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#endif

‎Lib/test/test_capi/test_type.py

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@@ -0,0 +1,27 @@
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from test.support import import_helper
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import unittest
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_testcapi = import_helper.import_module('_testcapi')
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class TypeTests(unittest.TestCase):
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def test_freeze(self):
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# test PyType_Freeze()
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type_freeze = _testcapi.type_freeze
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class MyType:
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pass
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MyType.attr = "mutable"
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type_freeze(MyType)
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with self.assertRaises(TypeError):
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MyType.attr = "immutable"
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# PyType_Freeze() requires base classes to be immutable
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class Mutable:
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"mutable base class"
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pass
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class MyType2(Mutable):
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pass
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with self.assertRaises(TypeError):
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type_freeze(MyType2)

‎Lib/test/test_stable_abi_ctypes.py

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‎Misc/NEWS.d/next/C_API/2024-07-30-14-40-08.gh-issue-121654.tgGeAl.rst

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@@ -0,0 +1,2 @@
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Add :c:func:`PyType_Freeze` function to make a type immutable. Patch by
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Victor Stinner.

‎Misc/stable_abi.toml

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@@ -2510,3 +2510,5 @@
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added = '3.14'
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[function.PyIter_NextItem]
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added = '3.14'
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[function.PyType_Freeze]
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added = '3.14'

‎Modules/_testcapimodule.c

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Original file line numberDiff line numberDiff line change
@@ -3329,6 +3329,19 @@ test_critical_sections(PyObject *module, PyObject *Py_UNUSED(args))
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Py_RETURN_NONE;
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}
33313331

3332+
static PyObject *
3333+
type_freeze(PyObject *module, PyObject *args)
3334+
{
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PyTypeObject *type;
3336+
if (!PyArg_ParseTuple(args, "O!", &PyType_Type, &type)) {
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return NULL;
3338+
}
3339+
if (PyType_Freeze(type) < 0) {
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return NULL;
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}
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Py_RETURN_NONE;
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}
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static PyMethodDef TestMethods[] = {
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{"set_errno", set_errno, METH_VARARGS},
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{"test_config", test_config, METH_NOARGS},
@@ -3469,6 +3482,7 @@ static PyMethodDef TestMethods[] = {
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{"test_weakref_capi", test_weakref_capi, METH_NOARGS},
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{"function_set_warning", function_set_warning, METH_NOARGS},
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{"test_critical_sections", test_critical_sections, METH_NOARGS},
3485+
{"type_freeze", type_freeze, METH_VARARGS},
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{NULL, NULL} /* sentinel */
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};
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‎Objects/typeobject.c

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Original file line numberDiff line numberDiff line change
@@ -4642,6 +4642,26 @@ check_basicsize_includes_size_and_offsets(PyTypeObject* type)
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return 1;
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}
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static int
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check_immutable_bases(const char *type_name, PyObject *bases)
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{
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for (Py_ssize_t i=0; i<PyTuple_GET_SIZE(bases); i++) {
4649+
PyTypeObject *b = (PyTypeObject*)PyTuple_GET_ITEM(bases, i);
4650+
if (!b) {
4651+
return -1;
4652+
}
4653+
if (!_PyType_HasFeature(b, Py_TPFLAGS_IMMUTABLETYPE)) {
4654+
PyErr_Format(
4655+
PyExc_TypeError,
4656+
"Creating immutable type %s from mutable base %N",
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type_name, b
4658+
);
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return -1;
4660+
}
4661+
}
4662+
return 0;
4663+
}
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46454665
static PyObject *
46464666
_PyType_FromMetaclass_impl(
46474667
PyTypeObject *metaclass, PyObject *module,
@@ -4798,19 +4818,8 @@ _PyType_FromMetaclass_impl(
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* and only heap types can be mutable.)
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*/
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if (spec->flags & Py_TPFLAGS_IMMUTABLETYPE) {
4801-
for (int i=0; i<PyTuple_GET_SIZE(bases); i++) {
4802-
PyTypeObject *b = (PyTypeObject*)PyTuple_GET_ITEM(bases, i);
4803-
if (!b) {
4804-
goto finally;
4805-
}
4806-
if (!_PyType_HasFeature(b, Py_TPFLAGS_IMMUTABLETYPE)) {
4807-
PyErr_Format(
4808-
PyExc_TypeError,
4809-
"Creating immutable type %s from mutable base %N",
4810-
spec->name, b
4811-
);
4812-
goto finally;
4813-
}
4821+
if (check_immutable_bases(spec->name, bases) < 0) {
4822+
goto finally;
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}
48154824
}
48164825

@@ -11178,6 +11187,18 @@ add_operators(PyTypeObject *type, PyTypeObject *def)
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}
1117911188

1118011189

11190+
int
11191+
PyType_Freeze(PyTypeObject *type)
11192+
{
11193+
PyObject *bases = type->tp_bases;
11194+
if (check_immutable_bases(type->tp_name, bases) < 0) {
11195+
return -1;
11196+
}
11197+
type->tp_flags |= Py_TPFLAGS_IMMUTABLETYPE;
11198+
return 0;
11199+
}
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11201+
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/* Cooperative 'super' */
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typedef struct {

‎PC/python3dll.c

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