From 019461232fecf82d05240a79ff6ccd03ee31fe19 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Fri, 4 Dec 2020 19:51:09 +0100
Subject: [PATCH 1/2] bpo-30459: Convert PyTuple_SET_ITEM() to a function

Convert the PyTuple_SET_ITEM(), PyList_SET_ITEM() and PyCell_SET()
macros to static inline functions.
---
 Include/cellobject.h                               | 12 ++++++++++--
 Include/cpython/listobject.h                       | 12 ++++++++++--
 Include/cpython/tupleobject.h                      | 14 ++++++++++----
 .../C API/2020-12-04-19-55-51.bpo-30459.3dmPs5.rst |  2 ++
 4 files changed, 32 insertions(+), 8 deletions(-)
 create mode 100644 Misc/NEWS.d/next/C API/2020-12-04-19-55-51.bpo-30459.3dmPs5.rst

diff --git a/Include/cellobject.h b/Include/cellobject.h
index f12aa90a42a8fe..dc5baa4fa4acaf 100644
--- a/Include/cellobject.h
+++ b/Include/cellobject.h
@@ -19,8 +19,16 @@ PyAPI_FUNC(PyObject *) PyCell_New(PyObject *);
 PyAPI_FUNC(PyObject *) PyCell_Get(PyObject *);
 PyAPI_FUNC(int) PyCell_Set(PyObject *, PyObject *);
 
-#define PyCell_GET(op) (((PyCellObject *)(op))->ob_ref)
-#define PyCell_SET(op, v) (((PyCellObject *)(op))->ob_ref = v)
+// Cast the argument to PyCellObject* type.
+#define _PyCell_CAST(op) (assert(PyCell_Check(op)), (PyCellObject *)(op))
+
+#define PyCell_GET(op) (_PyCell_CAST(op)->ob_ref)
+
+static inline void _PyCell_SET(PyCellObject *cell, PyObject *value)
+{
+    cell->ob_ref = value;
+}
+#define PyCell_SET(op, value) _PyCell_SET(_PyCell_CAST(op), value)
 
 #ifdef __cplusplus
 }
diff --git a/Include/cpython/listobject.h b/Include/cpython/listobject.h
index e1b9462d5b3612..8aacd6f5a921d7 100644
--- a/Include/cpython/listobject.h
+++ b/Include/cpython/listobject.h
@@ -29,6 +29,14 @@ PyAPI_FUNC(void) _PyList_DebugMallocStats(FILE *out);
 /* Cast argument to PyListObject* type. */
 #define _PyList_CAST(op) (assert(PyList_Check(op)), (PyListObject *)(op))
 
-#define PyList_GET_ITEM(op, i) (_PyList_CAST(op)->ob_item[i])
-#define PyList_SET_ITEM(op, i, v) (_PyList_CAST(op)->ob_item[i] = (v))
+#define PyList_GET_ITEM(op, index) (_PyList_CAST(op)->ob_item[index])
+
+static inline void
+_PyList_SET_ITEM(PyListObject *list, Py_ssize_t index, PyObject *item)
+{
+    list->ob_item[index] = item;
+}
+#define PyList_SET_ITEM(op, index, item) \
+    _PyList_SET_ITEM(_PyList_CAST(op), index, item)
+
 #define PyList_GET_SIZE(op)    Py_SIZE(_PyList_CAST(op))
diff --git a/Include/cpython/tupleobject.h b/Include/cpython/tupleobject.h
index 51dcd4237be18c..877f0b1e067c94 100644
--- a/Include/cpython/tupleobject.h
+++ b/Include/cpython/tupleobject.h
@@ -20,9 +20,15 @@ PyAPI_FUNC(void) _PyTuple_MaybeUntrack(PyObject *);
 
 #define PyTuple_GET_SIZE(op)    Py_SIZE(_PyTuple_CAST(op))
 
-#define PyTuple_GET_ITEM(op, i) (_PyTuple_CAST(op)->ob_item[i])
-
-/* Macro, *only* to be used to fill in brand new tuples */
-#define PyTuple_SET_ITEM(op, i, v) (_PyTuple_CAST(op)->ob_item[i] = v)
+#define PyTuple_GET_ITEM(op, index) (_PyTuple_CAST(op)->ob_item[index])
+
+// Function *only* to be used to fill in brand new tuples.
+static inline void
+_PyTuple_SET_ITEM(PyTupleObject *tuple, Py_ssize_t index, PyObject *item)
+{
+    tuple->ob_item[index] = item;
+}
+#define PyTuple_SET_ITEM(op, index, item) \
+    _PyTuple_SET_ITEM(_PyTuple_CAST(op), index, item)
 
 PyAPI_FUNC(void) _PyTuple_DebugMallocStats(FILE *out);
diff --git a/Misc/NEWS.d/next/C API/2020-12-04-19-55-51.bpo-30459.3dmPs5.rst b/Misc/NEWS.d/next/C API/2020-12-04-19-55-51.bpo-30459.3dmPs5.rst
new file mode 100644
index 00000000000000..5c78b2449835ea
--- /dev/null
+++ b/Misc/NEWS.d/next/C API/2020-12-04-19-55-51.bpo-30459.3dmPs5.rst	
@@ -0,0 +1,2 @@
+Convert the :c:func:`PyTuple_SET_ITEM()`, :c:func:`PyList_SET_ITEM()` and
+:c:func:`PyCell_SET()` macros to static inline functions.

From 9309a5932a4953829003dff4a3ee63559face3d4 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Sat, 5 Dec 2020 02:30:10 +0100
Subject: [PATCH 2/2] Add a note in What's New in Python 3.10

---
 Doc/whatsnew/3.10.rst | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Doc/whatsnew/3.10.rst b/Doc/whatsnew/3.10.rst
index a8f1080a504c70..083667a7c862c2 100644
--- a/Doc/whatsnew/3.10.rst
+++ b/Doc/whatsnew/3.10.rst
@@ -595,6 +595,10 @@ Porting to Python 3.10
   :ref:`Python Path Configuration.  <init-path-config>`.
   (Contributed by Victor Stinner in :issue:`42260`.)
 
+* Convert the :c:func:`PyTuple_SET_ITEM()`, :c:func:`PyList_SET_ITEM()` and
+  :c:func:`PyCell_SET()` macros to static inline functions.
+  (Contributed by Victor Stinner in :issue:`30459`.)
+
 Deprecated
 ----------