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Make int() and long() fall back to __trunc__(). See issue 2002.

This commit is contained in:
Jeffrey Yasskin 2008-02-04 01:04:35 +00:00
parent 72a6576279
commit a26cf9b760
5 changed files with 232 additions and 3 deletions
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13
Include/abstract.h
View File

@ -760,6 +760,19 @@ xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*/
PyAPI_FUNC(Py_ssize_t) PyNumber_AsSsize_t(PyObject *o, PyObject *exc);
/*
Returns the Integral instance converted to an int. The
instance is expected to be int or long or have an __int__
method. Steals integral's reference. error_format will be
used to create the TypeError if integral isn't actually an
Integral instance. error_format should be a format string
that can accept a char* naming integral's type.
*/
PyAPI_FUNC(PyObject *) _PyNumber_ConvertIntegralToInt(
PyObject *integral,
const char* error_format);
/*
Returns the object converted to Py_ssize_t by going through
PyNumber_Index first. If an overflow error occurs while

2
Lib/rational.py
View File

@ -424,8 +424,6 @@ class Rational(RationalAbc):
else:
return a.numerator // a.denominator
__int__ = __trunc__
def __hash__(self):
"""hash(self)

102
Lib/test/test_builtin.py
View File

@ -934,6 +934,14 @@ class BuiltinTest(unittest.TestCase):
def test_intconversion(self):
# Test __int__()
class ClassicMissingMethods:
pass
self.assertRaises(AttributeError, int, ClassicMissingMethods())
class MissingMethods(object):
pass
self.assertRaises(TypeError, int, MissingMethods())
class Foo0:
def __int__(self):
return 42
@ -965,6 +973,49 @@ class BuiltinTest(unittest.TestCase):
self.assertEqual(int(Foo4()), 42L)
self.assertRaises(TypeError, int, Foo5())
class Classic:
pass
for base in (object, Classic):
class IntOverridesTrunc(base):
def __int__(self):
return 42
def __trunc__(self):
return -12
self.assertEqual(int(IntOverridesTrunc()), 42)
class JustTrunc(base):
def __trunc__(self):
return 42
self.assertEqual(int(JustTrunc()), 42)
for trunc_result_base in (object, Classic):
class Integral(trunc_result_base):
def __int__(self):
return 42
class TruncReturnsNonInt(base):
def __trunc__(self):
return Integral()
self.assertEqual(int(TruncReturnsNonInt()), 42)
class NonIntegral(trunc_result_base):
def __trunc__(self):
# Check that we avoid infinite recursion.
return NonIntegral()
class TruncReturnsNonIntegral(base):
def __trunc__(self):
return NonIntegral()
try:
int(TruncReturnsNonIntegral())
except TypeError as e:
self.assertEquals(str(e),
"__trunc__ returned non-Integral"
" (type NonIntegral)")
else:
self.fail("Failed to raise TypeError with %s" %
((base, trunc_result_base),))
def test_intern(self):
self.assertRaises(TypeError, intern)
s = "never interned before"
@ -1207,6 +1258,14 @@ class BuiltinTest(unittest.TestCase):
def test_longconversion(self):
# Test __long__()
class ClassicMissingMethods:
pass
self.assertRaises(AttributeError, long, ClassicMissingMethods())
class MissingMethods(object):
pass
self.assertRaises(TypeError, long, MissingMethods())
class Foo0:
def __long__(self):
return 42L
@ -1238,6 +1297,49 @@ class BuiltinTest(unittest.TestCase):
self.assertEqual(long(Foo4()), 42)
self.assertRaises(TypeError, long, Foo5())
class Classic:
pass
for base in (object, Classic):
class LongOverridesTrunc(base):
def __long__(self):
return 42
def __trunc__(self):
return -12
self.assertEqual(long(LongOverridesTrunc()), 42)
class JustTrunc(base):
def __trunc__(self):
return 42
self.assertEqual(long(JustTrunc()), 42)
for trunc_result_base in (object, Classic):
class Integral(trunc_result_base):
def __int__(self):
return 42
class TruncReturnsNonLong(base):
def __trunc__(self):
return Integral()
self.assertEqual(long(TruncReturnsNonLong()), 42)
class NonIntegral(trunc_result_base):
def __trunc__(self):
# Check that we avoid infinite recursion.
return NonIntegral()
class TruncReturnsNonIntegral(base):
def __trunc__(self):
return NonIntegral()
try:
long(TruncReturnsNonIntegral())
except TypeError as e:
self.assertEquals(str(e),
"__trunc__ returned non-Integral"
" (type NonIntegral)")
else:
self.fail("Failed to raise TypeError with %s" %
((base, trunc_result_base),))
def test_map(self):
self.assertEqual(
map(None, 'hello world'),

94
Objects/abstract.c
View File

@ -1034,13 +1034,65 @@ PyNumber_AsSsize_t(PyObject *item, PyObject *err)
}
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 @@ PyNumber_Int(PyObject *o)
}
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 @@ PyNumber_Int(PyObject *o)
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 @@ PyObject *
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 @@ PyNumber_Long(PyObject *o)
}
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

24
Objects/classobject.c
View File

@ -1798,7 +1798,29 @@ instance_index(PyInstanceObject *self)
UNARY(instance_invert, "__invert__")
UNARY(instance_int, "__int__")
UNARY(_instance_trunc, "__trunc__")
static PyObject *
instance_int(PyInstanceObject *self)
{
PyObject *truncated;
static PyObject *int_name;
if (int_name == NULL) {
int_name = PyString_InternFromString("__int__");
if (int_name == NULL)
return NULL;
}
if (PyObject_HasAttr((PyObject*)self, int_name))
return generic_unary_op(self, int_name);
truncated = _instance_trunc(self);
/* __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)");
}
UNARY_FB(instance_long, "__long__", instance_int)
UNARY(instance_float, "__float__")
UNARY(instance_oct, "__oct__")