gh-91102: Port 8-argument _warnings.warn_explicit to Argument Clinic

Misc/NEWS.d/next/Core and Builtins/2022-05-11-09-16-54.gh-issue-91102.lenv9h.rst

@@ -0,0 +1,8 @@
+8-argument :meth:`_warnings.warn_explicit` is ported to Argument Clinic.
+Benefits:
+
+1. :c:data:`METH_VARARGS` calling convention is replaced with
+   a little faster :c:data:`METH_FASTCALL` (no extra tuple creation)
+2. :c:func:`PyArg_ParseTupleAndKeywords` call is replaced with
+   :c:func:`_PyArg_UnpackKeywords` and a tailored parser generated specially
+   for the ported function.

Python/_warnings.c

@@ -1031,28 +1031,31 @@ get_source_line(PyInterpreterState *interp, PyObject *module_globals, int lineno
     return source_line;
 }
 
+/*[clinic input]
+warn_explicit as warnings_warn_explicit
+
+    message: object
+    category: object
+    filename: unicode
+    lineno: int
+    mod: object = NULL
+    registry: object = None
+    module_globals: object = None
+    source as sourceobj: object = None
+
+Issue a warning, or maybe ignore it or raise an exception.
+[clinic start generated code]*/
+
 static PyObject *
-warnings_warn_explicit(PyObject *self, PyObject *args, PyObject *kwds)
+warnings_warn_explicit_impl(PyObject *module, PyObject *message,
+                            PyObject *category, PyObject *filename,
+                            int lineno, PyObject *mod, PyObject *registry,
+                            PyObject *module_globals, PyObject *sourceobj)
+/*[clinic end generated code: output=c49c62b15a49a186 input=81e348c13d2f0cda]*/
 {
-    static char *kwd_list[] = {"message", "category", "filename", "lineno",
-                                "module", "registry", "module_globals",
-                                "source", 0};
-    PyObject *message;
-    PyObject *category;
-    PyObject *filename;
-    int lineno;
-    PyObject *module = NULL;
-    PyObject *registry = NULL;
-    PyObject *module_globals = NULL;
-    PyObject *sourceobj = NULL;
     PyObject *source_line = NULL;
     PyObject *returned;
 
-    if (!PyArg_ParseTupleAndKeywords(args, kwds, "OOUi|OOOO:warn_explicit",
-                kwd_list, &message, &category, &filename, &lineno, &module,
-                &registry, &module_globals, &sourceobj))
-        return NULL;
-
     PyThreadState *tstate = get_current_tstate();
     if (tstate == NULL) {
         return NULL;
@@ -1071,7 +1074,7 @@ warnings_warn_explicit(PyObject *self, PyObject *args, PyObject *kwds)
             return NULL;
         }
     }
-    returned = warn_explicit(tstate, category, message, filename, lineno, module,
+    returned = warn_explicit(tstate, category, message, filename, lineno, mod,
                              registry, source_line, sourceobj);
     Py_XDECREF(source_line);
     return returned;
@@ -1348,13 +1351,9 @@ _PyErr_WarnUnawaitedCoroutine(PyObject *coro)
     }
 }
 
-PyDoc_STRVAR(warn_explicit_doc,
-"Low-level interface to warnings functionality.");
-
 static PyMethodDef warnings_functions[] = {
     WARNINGS_WARN_METHODDEF
-    {"warn_explicit", _PyCFunction_CAST(warnings_warn_explicit),
-        METH_VARARGS | METH_KEYWORDS, warn_explicit_doc},
+    WARNINGS_WARN_EXPLICIT_METHODDEF
     {"_filters_mutated", _PyCFunction_CAST(warnings_filters_mutated), METH_NOARGS,
         NULL},
     /* XXX(brett.cannon): add showwarning? */