Argument Clinic includes internal headers in generated output unconditionally

[erlend-aasland]

It seems like Argument Clinic generates code that define Py_BUILD_CORE and includes internal headers unconditionally; for example, a file with a METH_O function will have no need for those:

Details

/*[clinic input]
preserve
[clinic start generated code]*/

#if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
# include "pycore_gc.h" // PyGC_Head
# include "pycore_runtime.h" // _Py_ID()
#endif


PyDoc_STRVAR(func__doc__,
"func($module, a, /)\n"
"--\n"
"\n");

#define FUNC_METHODDEF \
 {"func", (PyCFunction)func, METH_O, func__doc__},
/*[clinic end generated code: output=851b6645c29cfa0d input=a9049054013a1b77]*/

OTOH, a METH_KEYWORDS function needs those:

Details

/*[clinic input]
preserve
[clinic start generated code]*/

#if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
# include "pycore_gc.h" // PyGC_Head
# include "pycore_runtime.h" // _Py_ID()
#endif


PyDoc_STRVAR(func__doc__,
"func($module, /, a, b)\n"
"--\n"
"\n");

#define FUNC_METHODDEF \
 {"func", _PyCFunction_CAST(func), METH_FASTCALL|METH_KEYWORDS, func__doc__},

static PyObject *
func_impl(PyObject *module, PyObject *a, PyObject *b);

static PyObject *
func(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
{
 PyObject *return_value = NULL;
 #if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)

 #define NUM_KEYWORDS 2
 static struct {
 PyGC_Head _this_is_not_used;
 PyObject_VAR_HEAD
 PyObject *ob_item[NUM_KEYWORDS];
 } _kwtuple = {
 .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
 .ob_item = { &_Py_ID(a), &_Py_ID(b), },
 };
 #undef NUM_KEYWORDS
 #define KWTUPLE (&_kwtuple.ob_base.ob_base)

 #else // !Py_BUILD_CORE
 # define KWTUPLE NULL
 #endif // !Py_BUILD_CORE

 static const char * const _keywords[] = {"a", "b", NULL};
 static _PyArg_Parser _parser = {
 .keywords = _keywords,
 .fname = "func",
 .kwtuple = KWTUPLE,
 };
 #undef KWTUPLE
 PyObject *argsbuf[2];
 PyObject *a;
 PyObject *b;

 args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
 if (!args) {
 goto exit;
 }
 a = args[0];
 b = args[1];
 return_value = func_impl(module, a, b);

exit:
 return return_value;
}
/*[clinic end generated code: output=e790cd95ffc517a0 input=a9049054013a1b77]*/

Argument Clinic should check if those defines/includes are needed before generating the output.

Linked PRs

• gh-107603: Argument Clinic can emit includes #108486
• GH-107603: Clinic: Pass specific attributes to print_block() #108581
• gh-107603: AC only includes pycore_gc.h if needed #108715
• gh-107603: Argument Clinic: Only include pycore_gc.h if needed #108726

[erlend-aasland]

'unconditionally' was a bit harsh, but it does generate core includes for some cases where it is not needed.

[kumaraditya303]

I don't think this is an important issue, this is more of a "nice to have" rather than necessary, it will probably add more conditional code. I certainly don't consider this as a bug though.

[erlend-aasland]

Yeah, it's not an important issue. But/feature? I'd say it is an undesirable feature, then :)

[vstinner]

I don't think this is an important issue, this is more of a "nice to have" rather than necessary, it will probably add more conditional code. I certainly don't consider this as a bug though.

I would like this feature to be able to remove private functions only used by AC from the public C API: issue #106320.