gh-65210: Add const qualifiers in PyArg_VaParseTupleAndKeywords() (GH-105958)

Change the declaration of the keywords parameter in functions
PyArg_ParseTupleAndKeywords() and PyArg_VaParseTupleAndKeywords() from `char **`
to `char * const *` in C and `const char * const *` in C++.

It makes these functions compatible with argument of type `const char * const *`,
`const char **` or `char * const *` in C++ and `char * const *` in C
without explicit type cast.

Co-authored-by: C.A.M. Gerlach <CAM.Gerlach@Gerlach.CAM>
This commit is contained in:
Serhiy Storchaka 2023-12-04 13:14:56 +02:00 committed by GitHub
parent cda737924f
commit da6760bdf5
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7 changed files with 57 additions and 13 deletions

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@ -413,7 +413,7 @@ API Functions
than a variable number of arguments.
.. c:function:: int PyArg_ParseTupleAndKeywords(PyObject *args, PyObject *kw, const char *format, char *keywords[], ...)
.. c:function:: int PyArg_ParseTupleAndKeywords(PyObject *args, PyObject *kw, const char *format, char * const *keywords, ...)
Parse the parameters of a function that takes both positional and keyword
parameters into local variables.
@ -424,15 +424,24 @@ API Functions
Returns true on success; on failure, it returns false and raises the
appropriate exception.
.. note::
The *keywords* parameter declaration is :c:expr:`char * const *` in C and
:c:expr:`const char * const *` in C++.
This can be overridden with the :c:macro:`PY_CXX_CONST` macro.
.. versionchanged:: 3.6
Added support for :ref:`positional-only parameters
<positional-only_parameter>`.
.. versionchanged:: 3.13
The *keywords* parameter has now type :c:expr:`char * const *` in C and
:c:expr:`const char * const *` in C++, instead of :c:expr:`char **`.
Added support for non-ASCII keyword parameter names.
.. c:function:: int PyArg_VaParseTupleAndKeywords(PyObject *args, PyObject *kw, const char *format, char *keywords[], va_list vargs)
.. c:function:: int PyArg_VaParseTupleAndKeywords(PyObject *args, PyObject *kw, const char *format, char * const *keywords, va_list vargs)
Identical to :c:func:`PyArg_ParseTupleAndKeywords`, except that it accepts a
va_list rather than a variable number of arguments.
@ -505,6 +514,19 @@ API Functions
PyArg_ParseTuple(args, "O|O:ref", &object, &callback)
.. c:macro:: PY_CXX_CONST
The value to be inserted, if any, before :c:expr:`char * const *`
in the *keywords* parameter declaration of
:c:func:`PyArg_ParseTupleAndKeywords` and
:c:func:`PyArg_VaParseTupleAndKeywords`.
Default empty for C and ``const`` for C++
(:c:expr:`const char * const *`).
To override, define it to the desired value before including
:file:`Python.h`.
.. versionadded:: 3.13
---------------
Building values

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@ -735,7 +735,7 @@ Keyword Parameters for Extension Functions
The :c:func:`PyArg_ParseTupleAndKeywords` function is declared as follows::
int PyArg_ParseTupleAndKeywords(PyObject *arg, PyObject *kwdict,
const char *format, char *kwlist[], ...);
const char *format, char * const *kwlist, ...);
The *arg* and *format* parameters are identical to those of the
:c:func:`PyArg_ParseTuple` function. The *kwdict* parameter is the dictionary of

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@ -1111,6 +1111,16 @@ New Features
APIs accepting the format codes always use ``Py_ssize_t`` for ``#`` formats.
(Contributed by Inada Naoki in :gh:`104922`.)
* The *keywords* parameter of :c:func:`PyArg_ParseTupleAndKeywords` and
:c:func:`PyArg_VaParseTupleAndKeywords` has now type :c:expr:`char * const *`
in C and :c:expr:`const char * const *` in C++, instead of :c:expr:`char **`.
It makes these functions compatible with arguments of type
:c:expr:`const char * const *`, :c:expr:`const char **` or
:c:expr:`char * const *` in C++ and :c:expr:`char * const *` in C
without an explicit type cast.
This can be overridden with the :c:macro:`PY_CXX_CONST` macro.
(Contributed by Serhiy Storchaka in :gh:`65210`.)
* Add :c:func:`PyImport_AddModuleRef`: similar to
:c:func:`PyImport_AddModule`, but return a :term:`strong reference` instead
of a :term:`borrowed reference`.

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@ -9,10 +9,10 @@ extern "C" {
PyAPI_FUNC(int) PyArg_Parse(PyObject *, const char *, ...);
PyAPI_FUNC(int) PyArg_ParseTuple(PyObject *, const char *, ...);
PyAPI_FUNC(int) PyArg_ParseTupleAndKeywords(PyObject *, PyObject *,
const char *, char **, ...);
const char *, PY_CXX_CONST char * const *, ...);
PyAPI_FUNC(int) PyArg_VaParse(PyObject *, const char *, va_list);
PyAPI_FUNC(int) PyArg_VaParseTupleAndKeywords(PyObject *, PyObject *,
const char *, char **, va_list);
const char *, PY_CXX_CONST char * const *, va_list);
PyAPI_FUNC(int) PyArg_ValidateKeywordArguments(PyObject *);
PyAPI_FUNC(int) PyArg_UnpackTuple(PyObject *, const char *, Py_ssize_t, Py_ssize_t, ...);

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@ -586,6 +586,14 @@ extern "C" {
# define ALIGNOF_MAX_ALIGN_T _Alignof(long double)
#endif
#ifndef PY_CXX_CONST
# ifdef __cplusplus
# define PY_CXX_CONST const
# else
# define PY_CXX_CONST
# endif
#endif
#if defined(__sgi) && !defined(_SGI_MP_SOURCE)
# define _SGI_MP_SOURCE
#endif

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@ -0,0 +1,3 @@
Change the declaration of the *keywords* parameter of
:c:func:`PyArg_ParseTupleAndKeywords` and
:c:func:`PyArg_VaParseTupleAndKeywords` for better compatibility with C++.

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@ -1,6 +1,7 @@
/* New getargs implementation */
#define PY_CXX_CONST const
#include "Python.h"
#include "pycore_abstract.h" // _PyNumber_Index()
#include "pycore_dict.h" // _PyDict_HasOnlyStringKeys()
@ -12,10 +13,10 @@
PyAPI_FUNC(int) _PyArg_Parse_SizeT(PyObject *, const char *, ...);
PyAPI_FUNC(int) _PyArg_ParseTuple_SizeT(PyObject *, const char *, ...);
PyAPI_FUNC(int) _PyArg_ParseTupleAndKeywords_SizeT(PyObject *, PyObject *,
const char *, char **, ...);
const char *, const char * const *, ...);
PyAPI_FUNC(int) _PyArg_VaParse_SizeT(PyObject *, const char *, va_list);
PyAPI_FUNC(int) _PyArg_VaParseTupleAndKeywords_SizeT(PyObject *, PyObject *,
const char *, char **, va_list);
const char *, const char * const *, va_list);
#define FLAG_COMPAT 1
@ -54,7 +55,7 @@ static Py_ssize_t convertbuffer(PyObject *, const void **p, const char **);
static int getbuffer(PyObject *, Py_buffer *, const char**);
static int vgetargskeywords(PyObject *, PyObject *,
const char *, char **, va_list *, int);
const char *, const char * const *, va_list *, int);
static int vgetargskeywordsfast(PyObject *, PyObject *,
struct _PyArg_Parser *, va_list *, int);
static int vgetargskeywordsfast_impl(PyObject *const *args, Py_ssize_t nargs,
@ -1247,7 +1248,7 @@ int
PyArg_ParseTupleAndKeywords(PyObject *args,
PyObject *keywords,
const char *format,
char **kwlist, ...)
const char * const *kwlist, ...)
{
int retval;
va_list va;
@ -1271,7 +1272,7 @@ int
_PyArg_ParseTupleAndKeywords_SizeT(PyObject *args,
PyObject *keywords,
const char *format,
char **kwlist, ...)
const char * const *kwlist, ...)
{
int retval;
va_list va;
@ -1297,7 +1298,7 @@ int
PyArg_VaParseTupleAndKeywords(PyObject *args,
PyObject *keywords,
const char *format,
char **kwlist, va_list va)
const char * const *kwlist, va_list va)
{
int retval;
va_list lva;
@ -1322,7 +1323,7 @@ int
_PyArg_VaParseTupleAndKeywords_SizeT(PyObject *args,
PyObject *keywords,
const char *format,
char **kwlist, va_list va)
const char * const *kwlist, va_list va)
{
int retval;
va_list lva;
@ -1460,7 +1461,7 @@ PyArg_ValidateKeywordArguments(PyObject *kwargs)
static int
vgetargskeywords(PyObject *args, PyObject *kwargs, const char *format,
char **kwlist, va_list *p_va, int flags)
const char * const *kwlist, va_list *p_va, int flags)
{
char msgbuf[512];
int levels[32];