diff --git a/Include/pymacro.h b/Include/pymacro.h index 7ecce44a0d2a42..a823d5535665b2 100644 --- a/Include/pymacro.h +++ b/Include/pymacro.h @@ -174,23 +174,27 @@ } while(0) #endif -/* Get the number of elements in a visible array - - This does not work on pointers, or arrays declared as [], or function - parameters. With correct compiler support, such usage will cause a build - error (see Py_BUILD_ASSERT_EXPR). - - Written by Rusty Russell, public domain, http://ccodearchive.net/ - - Requires at GCC 3.1+ */ -#if (defined(__GNUC__) && !defined(__STRICT_ANSI__) && \ - (((__GNUC__ == 3) && (__GNUC_MINOR__ >= 1)) || (__GNUC__ >= 4))) -/* Two gcc extensions. - &a[0] degrades to a pointer: a different type from an array */ +// Get the number of elements in a visible array. +// +// This does not work on pointers, or arrays declared as [], or function +// parameters. With correct compiler support, such usage will cause a build +// error (see Py_BUILD_ASSERT_EXPR). +// +// Written by Rusty Russell, public domain, http://ccodearchive.net/ +// +// Require GCC 4 (it works on GCC 3.1). +// +// Two GCC extensions: &a[0] degrades to a pointer, a different type from an +// array. +// +// gh-158810: Do not use __builtin_types_compatible_p() in strict C ANSI mode +// and on C++. +#if (defined(__GNUC__) && __GNUC__ >= 4 && defined(_Py_TYPEOF) \ + && !defined(__STRICT_ANSI__) && !defined(__cplusplus)) #define Py_ARRAY_LENGTH(array) \ (sizeof(array) / sizeof((array)[0]) \ - + Py_BUILD_ASSERT_EXPR(!__builtin_types_compatible_p(typeof(array), \ - typeof(&(array)[0])))) + + Py_BUILD_ASSERT_EXPR(!__builtin_types_compatible_p(_Py_TYPEOF(array), \ + _Py_TYPEOF(&(array)[0])))) #else #define Py_ARRAY_LENGTH(array) \ (sizeof(array) / sizeof((array)[0])) diff --git a/Lib/test/test_cext/extension.c b/Lib/test/test_cext/extension.c index e13f0c7911866b..dd2895520f751d 100644 --- a/Lib/test/test_cext/extension.c +++ b/Lib/test/test_cext/extension.c @@ -82,6 +82,8 @@ static PyObject * test_macros(PyObject *Py_UNUSED(module), PyObject *Py_UNUSED(args)) { PyObject *obj, *dict; + PyObject *slots[1]; + int small_array[] = {2, 5, 7}; // test Py_BUILD_ASSERT() and Py_BUILD_ASSERT_EXPR() Py_BUILD_ASSERT(sizeof(int) == sizeof(unsigned int)); @@ -97,17 +99,32 @@ test_macros(PyObject *Py_UNUSED(module), PyObject *Py_UNUSED(args)) Py_CLEAR(obj); assert(obj == _Py_NULL); + // gh-157649: Test Py_CLEAR() on an array + slots[0] = Py_None; + Py_CLEAR(slots[0]); + assert(slots[0] == _Py_NULL); + #ifndef Py_LIMITED_API // Test Py_SETREF(): use typeof()/__typeof__() if available, or memcpy() obj = Py_None; Py_SETREF(obj, _Py_NULL); assert(obj == _Py_NULL); + // gh-157649: Test Py_SETREF() on an array + slots[0] = Py_None; + Py_SETREF(slots[0], _Py_NULL); + assert(slots[0] == _Py_NULL); + // Test Py_XSETREF(): use typeof()/__typeof__() if available, or memcpy() obj = Py_None; Py_XSETREF(obj, _Py_NULL); assert(obj == _Py_NULL); -#endif + + // gh-157649: Test Py_XSETREF() on an array + slots[0] = Py_None; + Py_XSETREF(slots[0], _Py_NULL); + assert(slots[0] == _Py_NULL); +#endif // !Py_LIMITED_API // Test that Py_BEGIN_CRITICAL_SECTION is available dict = PyDict_New(); @@ -118,6 +135,9 @@ test_macros(PyObject *Py_UNUSED(module), PyObject *Py_UNUSED(args)) Py_END_CRITICAL_SECTION(); Py_DECREF(dict); + // Test Py_ARRAY_LENGTH() + assert(Py_ARRAY_LENGTH(small_array) == 3); + Py_RETURN_NONE; } diff --git a/Lib/test/test_cext/setup.py b/Lib/test/test_cext/setup.py index 2ef48261eadd1a..10a3887931932a 100644 --- a/Lib/test/test_cext/setup.py +++ b/Lib/test/test_cext/setup.py @@ -155,7 +155,7 @@ def main(): # option emits a C++ compiler warning. Remove "-std11" option from the # CC command. cmd = (sysconfig.get_config_var('CC') or '') - if cmd is not None: + if cmd is not None and 'CC' not in os.environ: if support.MS_WINDOWS: std_prefix = '/std' else: diff --git a/Misc/NEWS.d/next/C_API/2026-10-05-01-09-32.gh-issue-158810.F1p-PK.rst b/Misc/NEWS.d/next/C_API/2026-10-05-01-09-32.gh-issue-158810.F1p-PK.rst new file mode 100644 index 00000000000000..8d0878fd057a04 --- /dev/null +++ b/Misc/NEWS.d/next/C_API/2026-10-05-01-09-32.gh-issue-158810.F1p-PK.rst @@ -0,0 +1,2 @@ +Fix :c:macro:`Py_ARRAY_LENGTH()` macro on C++: do not use +``__builtin_types_compatible_p()`` on C++. Patch by Victor Stinner.