8000 gh-106168: PyTuple_SET_ITEM() now checks the index (#106164) · python/cpython@3f8483c · GitHub
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gh-106168: PyTuple_SET_ITEM() now checks the index (#106164)
PyTuple_SET_ITEM() and PyList_SET_ITEM() now check the index argument with an assertion if Python is built in debug mode or is built with assertions. * list_extend() and _PyList_AppendTakeRef() now set the list size before calling PyList_SET_ITEM(). * PyStructSequence_GetItem() and PyStructSequence_SetItem() now check the index argument: must be lesser than REAL_SIZE(op). * PyStructSequence_GET_ITEM() and PyStructSequence_SET_ITEM() are now aliases to PyStructSequence_GetItem() and PyStructSequence_SetItem().
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‎Doc/c-api/list.rst

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@@ -86,6 +86,10 @@ List Objects
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Macro form of :c:func:`PyList_SetItem` without error checking. This is
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normally only used to fill in new lists where there is no previous content.
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Bounds checking is performed as an assertion if Python is built in
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:ref:`debug mode <debug-build>` or :option:`with assertions
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<--with-assertions>`.
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.. note::
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This macro "steals" a reference to *item*, and, unlike

‎Doc/c-api/tuple.rst

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@@ -89,6 +89,9 @@ Tuple Objects
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Like :c:func:`PyTuple_SetItem`, but does no error checking, and should *only* be
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used to fill in brand new tuples.
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Bounds checking is performed as an assertion if Python is built in
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:ref:`debug mode <debug-build>` or :option:`with assertions <--with-assertions>`.
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.. note::
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This function "steals" a reference to *o*, and, unlike
@@ -194,12 +197,17 @@ type.
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.. c:function:: PyObject* PyStructSequence_GetItem(PyObject *p, Py_ssize_t pos)
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Return the object at position *pos* in the struct sequence pointed to by *p*.
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No bounds checking is performed.
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Bounds checking is performed as an assertion if Python is built in
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:ref:`debug mode <debug-build>` or :option:`with assertions <--with-assertions>`.
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.. c:function:: PyObject* PyStructSequence_GET_ITEM(PyObject *p, Py_ssize_t pos)
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Macro equivalent of :c:func:`PyStructSequence_GetItem`.
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Alias to :c:func:`PyStructSequence_GetItem`.
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.. versionchanged:: 3.13
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Now implemented as an alias to :c:func:`PyStructSequence_GetItem`.
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.. c:function:: void PyStructSequence_SetItem(PyObject *p, Py_ssize_t pos, PyObject *o)
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:c:func:`PyTuple_SET_ITEM`, this should only be used to fill in brand new
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instances.
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Bounds checking is performed as an assertion if Python is built in
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:ref:`debug mode <debug-build>` or :option:`with assertions <--with-assertions>`.
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.. note::
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This function "steals" a reference to *o*.
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.. c:function:: void PyStructSequence_SET_ITEM(PyObject *p, Py_ssize_t *pos, PyObject *o)
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Similar to :c:func:`PyStructSequence_SetItem`, but implemented as a static
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inlined function.
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Alias to :c:func:`PyStructSequence_SetItem`.
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.. note::
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This function "steals" a reference to *o*.
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.. versionchanged:: 3.13
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Now implemented as an alias to :c:func:`PyStructSequence_SetItem`.

‎Doc/whatsnew/3.13.rst

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@@ -441,6 +441,12 @@ New Features
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``NULL`` if the referent is no longer live.
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(Contributed by Victor Stinner in :gh:`105927`.)
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* If Python is built in :ref:`debug mode <debug-build>` or :option:`with
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assertions <--with-assertions>`, :c:func:`PyTuple_SET_ITEM` and
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:c:func:`PyList_SET_ITEM` now check the index argument with an assertion.
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If the assertion fails, make sure that the size is set before.
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(Contributed by Victor Stinner in :gh:`106168`.)
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Porting to Python 3.13
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----------------------
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‎Include/cpython/listobject.h

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@@ -41,6 +41,8 @@ static inline Py_ssize_t PyList_GET_SIZE(PyObject *op) {
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static inline void
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PyList_SET_ITEM(PyObject *op, Py_ssize_t index, PyObject *value) {
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PyListObject *list = _PyList_CAST(op);
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assert(0 <= index);
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assert(index < Py_SIZE(list));
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list->ob_item[index] = value;
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}
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#define PyList_SET_ITEM(op, index, value) \

‎Include/cpython/tupleobject.h

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@@ -31,6 +31,8 @@ static inline Py_ssize_t PyTuple_GET_SIZE(PyObject *op) {
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static inline void
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PyTuple_SET_ITEM(PyObject *op, Py_ssize_t index, PyObject *value) {
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PyTupleObject *tuple = _PyTuple_CAST(op);
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assert(0 <= index);
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assert(index < Py_SIZE(tuple));
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tuple->ob_item[index] = value;
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}
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#define PyTuple_SET_ITEM(op, index, value) \

‎Include/internal/pycore_list.h

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@@ -49,8 +49,8 @@ _PyList_AppendTakeRef(PyListObject *self, PyObject *newitem)
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Py_ssize_t allocated = self->allocated;
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assert((size_t)len + 1 < PY_SSIZE_T_MAX);
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if (allocated > len) {
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PyList_SET_ITEM(self, len, newitem);
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Py_SET_SIZE(self, len + 1);
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PyList_SET_ITEM(self, len, newitem);
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return 0;
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}
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return _PyList_AppendTakeRefListResize(self, newitem);

‎Include/structseq.h

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@@ -31,18 +31,15 @@ PyAPI_FUNC(PyTypeObject*) PyStructSequence_NewType(PyStructSequence_Desc *desc);
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PyAPI_FUNC(PyObject *) PyStructSequence_New(PyTypeObject* type);
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PyAPI_FUNC(void) PyStructSequence_SetItem(PyObject*, Py_ssize_t, PyObject*);
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PyAPI_FUNC(PyObject*) PyStructSequence_GetItem(PyObject*, Py_ssize_t);
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#ifndef Py_LIMITED_API
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typedef PyTupleObject PyStructSequence;
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/* Macro, *only* to be used to fill in brand new objects */
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#define PyStructSequence_SET_ITEM(op, i, v) PyTuple_SET_ITEM((op), (i), (v))
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#define PyStructSequence_GET_ITEM(op, i) PyTuple_GET_ITEM((op), (i))
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#define PyStructSequence_SET_ITEM PyStructSequence_SetItem
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#define PyStructSequence_GET_ITEM PyStructSequence_GetItem
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#endif
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43-
PyAPI_FUNC(void) PyStructSequence_SetItem(PyObject*, Py_ssize_t, PyObject*);
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PyAPI_FUNC(PyObject*) PyStructSequence_GetItem(PyObject*, Py_ssize_t);
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#ifdef __cplusplus
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}
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#endif

‎Misc/NEWS.d/next/C API/2023-06-28-02-30-50.gh-issue-106168.NFOZPv.rst

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If Python is built in :ref:`debug mode <debug-build>` or :option:`with
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assertions <--with-assertions>`, :c:func:`PyTuple_SET_ITEM` and
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:c:func:`PyList_SET_ITEM` now check the index argument with an assertion. If
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the assertion fails, make sure that the size is set before. Patch by Victor
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Stinner.

‎Objects/listobject.c

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@@ -953,8 +953,9 @@ list_extend(PyListObject *self, PyObject *iterable)
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}
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if (Py_SIZE(self) < self->allocated) {
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/* steals ref */
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PyList_SET_ITEM(self, Py_SIZE(self), item);
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Py_SET_SIZE(self, Py_SIZE(self) + 1);
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Py_ssize_t len = Py_SIZE(self);
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Py_SET_SIZE(self, len + 1);
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PyList_SET_ITEM(self, len, item);
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}
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else {
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if (_PyList_AppendTakeRef(self, item) < 0)

‎Objects/structseq.c

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@@ -74,15 +74,28 @@ PyStructSequence_New(PyTypeObject *type)
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}
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void
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PyStructSequence_SetItem(PyObject* op, Py_ssize_t i, PyObject* v)
77+
PyStructSequence_SetItem(PyObject *op, Py_ssize_t index, PyObject *value)
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{
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PyStructSequence_SET_ITEM(op, i, v);
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PyTupleObject *tuple = _PyTuple_CAST(op);
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assert(0 <= index);
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#ifndef NDEBUG
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Py_ssize_t n_fields = REAL_SIZE(op);
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assert(n_fields >= 0);
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assert(index < n_fields);
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#endif
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tuple->ob_item[index] = value;
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}
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PyObject*
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PyStructSequence_GetItem(PyObject* op, Py_ssize_t i)
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PyStructSequence_GetItem(PyObject *op, Py_ssize_t index)
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{
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return PyStructSequence_GET_ITEM(op, i);
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assert(0 <= index);
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#ifndef NDEBUG
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Py_ssize_t n_fields = REAL_SIZE(op);
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assert(n_fields >= 0);
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assert(index < n_fields);
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#endif
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return PyTuple_GET_ITEM(op, index);
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}
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@@ -287,7 +300,7 @@ structseq_repr(PyStructSequence *obj)
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goto error;
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}
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PyObject *value = PyStructSequence_GET_ITEM(obj, i);
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PyObject *value = PyStructSequence_GetItem((PyObject*)obj, i);
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assert(value != NULL);
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PyObject *repr = PyObject_Repr(value);
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if (repr == NULL) {

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