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bpo-35992: Use PySequence_GetItem only if sq_item is not NULL (GH-11857) · python/cpython@a7f929d

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3 files changed

lines changed

  • Misc/NEWS.d/next/Core and Builtins

3 files changed

lines changed

Original file line numberDiff line numberDiff line change

@@ -248,7 +248,14 @@ def __class_getitem__(cls, item):

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return f'{cls.__name__}[{item.__name__}]'

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self.assertEqual(Meta[int], 'Meta[int]')

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251-

def test_class_getitem_metaclass_2(self):

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def test_class_getitem_with_metaclass(self):

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class Meta(type): pass

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class C(metaclass=Meta):

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def __class_getitem__(cls, item):

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return f'{cls.__name__}[{item.__name__}]'

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self.assertEqual(C[int], 'C[int]')

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def test_class_getitem_metaclass_first(self):

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class Meta(type):

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def __getitem__(cls, item):

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return 'from metaclass'

Original file line numberDiff line numberDiff line change

@@ -0,0 +1,2 @@

1+

Fix ``__class_getitem__()`` not being called on a class with a custom

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non-subscriptable metaclass.

Original file line numberDiff line numberDiff line change

@@ -143,6 +143,7 @@ PyObject *

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PyObject_GetItem(PyObject *o, PyObject *key)

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{

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PyMappingMethods *m;

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PySequenceMethods *ms;

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if (o == NULL || key == NULL) {

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return null_error();

@@ -155,17 +156,19 @@ PyObject_GetItem(PyObject *o, PyObject *key)

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return item;

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}

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158-

if (o->ob_type->tp_as_sequence) {

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ms = o->ob_type->tp_as_sequence;

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if (ms && ms->sq_item) {

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if (PyIndex_Check(key)) {

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Py_ssize_t key_value;

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key_value = PyNumber_AsSsize_t(key, PyExc_IndexError);

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if (key_value == -1 && PyErr_Occurred())

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return NULL;

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return PySequence_GetItem(o, key_value);

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}

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else if (o->ob_type->tp_as_sequence->sq_item)

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else {

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return type_error("sequence index must "

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"be integer, not '%.200s'", key);

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}

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}

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if (PyType_Check(o)) {