Make int() and long() fall back to __trunc__(). See issue 2002.
diff --git a/Objects/abstract.c b/Objects/abstract.c
index 830fe82..a3e159a 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -1035,12 +1035,64 @@
PyObject *
+_PyNumber_ConvertIntegralToInt(PyObject *integral, const char* error_format)
+{
+ const char *type_name;
+ static PyObject *int_name = NULL;
+ if (int_name == NULL) {
+ int_name = PyString_InternFromString("__int__");
+ if (int_name == NULL)
+ return NULL;
+ }
+
+ if (integral && (!PyInt_Check(integral) &&
+ !PyLong_Check(integral))) {
+ /* Don't go through tp_as_number->nb_int to avoid
+ hitting the classic class fallback to __trunc__. */
+ PyObject *int_func = PyObject_GetAttr(integral, int_name);
+ if (int_func == NULL) {
+ PyErr_Clear(); /* Raise a different error. */
+ goto non_integral_error;
+ }
+ Py_DECREF(integral);
+ integral = PyEval_CallObject(int_func, NULL);
+ Py_DECREF(int_func);
+ if (integral && (!PyInt_Check(integral) &&
+ !PyLong_Check(integral))) {
+ goto non_integral_error;
+ }
+ }
+ return integral;
+
+non_integral_error:
+ if (PyInstance_Check(integral)) {
+ type_name = PyString_AS_STRING(((PyInstanceObject *)integral)
+ ->in_class->cl_name);
+ }
+ else {
+ type_name = integral->ob_type->tp_name;
+ }
+ PyErr_Format(PyExc_TypeError, error_format, type_name);
+ Py_DECREF(integral);
+ return NULL;
+}
+
+
+PyObject *
PyNumber_Int(PyObject *o)
{
PyNumberMethods *m;
+ static PyObject *trunc_name = NULL;
+ PyObject *trunc_func;
const char *buffer;
Py_ssize_t buffer_len;
+ if (trunc_name == NULL) {
+ trunc_name = PyString_InternFromString("__trunc__");
+ if (trunc_name == NULL)
+ return NULL;
+ }
+
if (o == NULL)
return null_error();
if (PyInt_CheckExact(o)) {
@@ -1049,6 +1101,7 @@
}
m = o->ob_type->tp_as_number;
if (m && m->nb_int) { /* This should include subclasses of int */
+ /* Classic classes always take this branch. */
PyObject *res = m->nb_int(o);
if (res && (!PyInt_Check(res) && !PyLong_Check(res))) {
PyErr_Format(PyExc_TypeError,
@@ -1063,6 +1116,18 @@
PyIntObject *io = (PyIntObject*)o;
return PyInt_FromLong(io->ob_ival);
}
+ trunc_func = PyObject_GetAttr(o, trunc_name);
+ if (trunc_func) {
+ PyObject *truncated = PyEval_CallObject(trunc_func, NULL);
+ Py_DECREF(trunc_func);
+ /* __trunc__ is specified to return an Integral type, but
+ int() needs to return an int. */
+ return _PyNumber_ConvertIntegralToInt(
+ truncated,
+ "__trunc__ returned non-Integral (type %.200s)");
+ }
+ PyErr_Clear(); /* It's not an error if o.__trunc__ doesn't exist. */
+
if (PyString_Check(o))
return int_from_string(PyString_AS_STRING(o),
PyString_GET_SIZE(o));
@@ -1102,13 +1167,22 @@
PyNumber_Long(PyObject *o)
{
PyNumberMethods *m;
+ static PyObject *trunc_name = NULL;
+ PyObject *trunc_func;
const char *buffer;
Py_ssize_t buffer_len;
+ if (trunc_name == NULL) {
+ trunc_name = PyString_InternFromString("__trunc__");
+ if (trunc_name == NULL)
+ return NULL;
+ }
+
if (o == NULL)
return null_error();
m = o->ob_type->tp_as_number;
if (m && m->nb_long) { /* This should include subclasses of long */
+ /* Classic classes always take this branch. */
PyObject *res = m->nb_long(o);
if (res && (!PyInt_Check(res) && !PyLong_Check(res))) {
PyErr_Format(PyExc_TypeError,
@@ -1121,6 +1195,26 @@
}
if (PyLong_Check(o)) /* A long subclass without nb_long */
return _PyLong_Copy((PyLongObject *)o);
+ trunc_func = PyObject_GetAttr(o, trunc_name);
+ if (trunc_func) {
+ PyObject *truncated = PyEval_CallObject(trunc_func, NULL);
+ PyObject *int_instance;
+ Py_DECREF(trunc_func);
+ /* __trunc__ is specified to return an Integral type,
+ but long() needs to return a long. */
+ int_instance = _PyNumber_ConvertIntegralToInt(
+ truncated,
+ "__trunc__ returned non-Integral (type %.200s)");
+ if (int_instance && PyInt_Check(int_instance)) {
+ /* Make sure that long() returns a long instance. */
+ long value = PyInt_AS_LONG(int_instance);
+ Py_DECREF(int_instance);
+ return PyLong_FromLong(value);
+ }
+ return int_instance;
+ }
+ PyErr_Clear(); /* It's not an error if o.__trunc__ doesn't exist. */
+
if (PyString_Check(o))
/* need to do extra error checking that PyLong_FromString()
* doesn't do. In particular long('9.5') must raise an