bpo-39200: Correct the error message for range() empty constructor (GH-17813)
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
diff --git a/Objects/rangeobject.c b/Objects/rangeobject.c
index 239ace6..9311f8b 100644
--- a/Objects/rangeobject.c
+++ b/Objects/rangeobject.c
@@ -77,37 +77,52 @@
if (!_PyArg_NoKeywords("range", kw))
return NULL;
- if (PyTuple_Size(args) <= 1) {
- if (!PyArg_UnpackTuple(args, "range", 1, 1, &stop))
- return NULL;
- stop = PyNumber_Index(stop);
- if (!stop)
- return NULL;
- Py_INCREF(_PyLong_Zero);
- start = _PyLong_Zero;
- Py_INCREF(_PyLong_One);
- step = _PyLong_One;
- }
- else {
- if (!PyArg_UnpackTuple(args, "range", 2, 3,
- &start, &stop, &step))
- return NULL;
+ Py_ssize_t num_args = PyTuple_GET_SIZE(args);
+ switch (num_args) {
+ case 3:
+ step = PyTuple_GET_ITEM(args, 2);
+ /* fallthrough */
+ case 2:
+ start = PyTuple_GET_ITEM(args, 0);
+ start = PyNumber_Index(start);
+ if (!start) {
+ return NULL;
+ }
- /* Convert borrowed refs to owned refs */
- start = PyNumber_Index(start);
- if (!start)
+ stop = PyTuple_GET_ITEM(args, 1);
+ stop = PyNumber_Index(stop);
+ if (!stop) {
+ Py_DECREF(start);
+ return NULL;
+ }
+
+ step = validate_step(step);
+ if (!step) {
+ Py_DECREF(start);
+ Py_DECREF(stop);
+ return NULL;
+ }
+ break;
+ case 1:
+ stop = PyTuple_GET_ITEM(args, 0);
+ stop = PyNumber_Index(stop);
+ if (!stop) {
+ return NULL;
+ }
+ Py_INCREF(_PyLong_Zero);
+ start = _PyLong_Zero;
+ Py_INCREF(_PyLong_One);
+ step = _PyLong_One;
+ break;
+ case 0:
+ PyErr_SetString(PyExc_TypeError,
+ "range expected at least 1 argument, got 0");
return NULL;
- stop = PyNumber_Index(stop);
- if (!stop) {
- Py_DECREF(start);
+ default:
+ PyErr_Format(PyExc_TypeError,
+ "range expected at most 3 arguments, got %zd",
+ num_args);
return NULL;
- }
- step = validate_step(step); /* Caution, this can clear exceptions */
- if (!step) {
- Py_DECREF(start);
- Py_DECREF(stop);
- return NULL;
- }
}
obj = make_range_object(type, start, stop, step);