bpo-42979: Enhance abstract.c assertions checking slot result (GH-24352)

* bpo-42979: Enhance abstract.c assertions checking slot result

Add _Py_CheckSlotResult() function which fails with a fatal error if
a slot function succeeded with an exception set or failed with no
exception set: write the slot name, the type name and the current
exception (if an exception is set).
This commit is contained in:
Victor Stinner 2021-01-27 17:39:16 +01:00 committed by GitHub
parent eeb701adc0
commit c9b8e9c421
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GPG Key ID: 4AEE18F83AFDEB23
6 changed files with 126 additions and 51 deletions

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@ -376,4 +376,4 @@ PyAPI_FUNC(void) _Py_add_one_to_index_C(int nd, Py_ssize_t *index,
PyAPI_FUNC(int) _Py_convert_optional_to_ssize_t(PyObject *, void *);
/* Same as PyNumber_Index but can return an instance of a subclass of int. */
PyAPI_FUNC(PyObject *) _PyNumber_Index(PyObject *o);
PyAPI_FUNC(PyObject *) _PyNumber_Index(PyObject *o);

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@ -168,6 +168,12 @@ _PyObject_IS_GC(PyObject *obj)
// Fast inlined version of PyType_IS_GC()
#define _PyType_IS_GC(t) _PyType_HasFeature((t), Py_TPFLAGS_HAVE_GC)
// Usage: assert(_Py_CheckSlotResult(obj, "__getitem__", result != NULL)));
extern int _Py_CheckSlotResult(
PyObject *obj,
const char *slot_name,
int success);
#ifdef __cplusplus
}
#endif

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@ -2,6 +2,8 @@
# these are all functions _testcapi exports whose name begins with 'test_'.
from collections import OrderedDict
import importlib.machinery
import importlib.util
import os
import pickle
import random
@ -13,8 +15,6 @@ import threading
import time
import unittest
import weakref
import importlib.machinery
import importlib.util
from test import support
from test.support import MISSING_C_DOCSTRINGS
from test.support import import_helper
@ -35,6 +35,10 @@ import _testinternalcapi
Py_DEBUG = hasattr(sys, 'gettotalrefcount')
def decode_stderr(err):
return err.decode('utf-8', 'replace').replace('\r', '')
def testfunction(self):
"""some doc"""
return self
@ -207,23 +211,22 @@ class CAPITest(unittest.TestCase):
_testcapi.return_null_without_error()
""")
rc, out, err = assert_python_failure('-c', code)
self.assertRegex(err.replace(b'\r', b''),
br'Fatal Python error: _Py_CheckFunctionResult: '
br'a function returned NULL '
br'without setting an error\n'
br'Python runtime state: initialized\n'
br'SystemError: <built-in function '
br'return_null_without_error> returned NULL '
br'without setting an error\n'
br'\n'
br'Current thread.*:\n'
br' File .*", line 6 in <module>')
err = decode_stderr(err)
self.assertRegex(err,
r'Fatal Python error: _Py_CheckFunctionResult: '
r'a function returned NULL without setting an exception\n'
r'Python runtime state: initialized\n'
r'SystemError: <built-in function return_null_without_error> '
r'returned NULL without setting an exception\n'
r'\n'
r'Current thread.*:\n'
r' File .*", line 6 in <module>\n')
else:
with self.assertRaises(SystemError) as cm:
_testcapi.return_null_without_error()
self.assertRegex(str(cm.exception),
'return_null_without_error.* '
'returned NULL without setting an error')
'returned NULL without setting an exception')
def test_return_result_with_error(self):
# Issue #23571: A function must not return a result with an error set
@ -236,28 +239,58 @@ class CAPITest(unittest.TestCase):
_testcapi.return_result_with_error()
""")
rc, out, err = assert_python_failure('-c', code)
self.assertRegex(err.replace(b'\r', b''),
br'Fatal Python error: _Py_CheckFunctionResult: '
br'a function returned a result '
br'with an error set\n'
br'Python runtime state: initialized\n'
br'ValueError\n'
br'\n'
br'The above exception was the direct cause '
br'of the following exception:\n'
br'\n'
br'SystemError: <built-in '
br'function return_result_with_error> '
br'returned a result with an error set\n'
br'\n'
br'Current thread.*:\n'
br' File .*, line 6 in <module>')
err = decode_stderr(err)
self.assertRegex(err,
r'Fatal Python error: _Py_CheckFunctionResult: '
r'a function returned a result with an exception set\n'
r'Python runtime state: initialized\n'
r'ValueError\n'
r'\n'
r'The above exception was the direct cause '
r'of the following exception:\n'
r'\n'
r'SystemError: <built-in '
r'function return_result_with_error> '
r'returned a result with an exception set\n'
r'\n'
r'Current thread.*:\n'
r' File .*, line 6 in <module>\n')
else:
with self.assertRaises(SystemError) as cm:
_testcapi.return_result_with_error()
self.assertRegex(str(cm.exception),
'return_result_with_error.* '
'returned a result with an error set')
'returned a result with an exception set')
def test_getitem_with_error(self):
# Test _Py_CheckSlotResult(). Raise an exception and then calls
# PyObject_GetItem(): check that the assertion catchs the bug.
# PyObject_GetItem() must not be called with an exception set.
code = textwrap.dedent("""
import _testcapi
from test import support
with support.SuppressCrashReport():
_testcapi.getitem_with_error({1: 2}, 1)
""")
rc, out, err = assert_python_failure('-c', code)
err = decode_stderr(err)
if 'SystemError: ' not in err:
self.assertRegex(err,
r'Fatal Python error: _Py_CheckSlotResult: '
r'Slot __getitem__ of type dict succeeded '
r'with an exception set\n'
r'Python runtime state: initialized\n'
r'ValueError: bug\n'
r'\n'
r'Current thread .* \(most recent call first\):\n'
r' File .*, line 6 in <module>\n'
r'\n'
r'Extension modules: _testcapi \(total: 1\)\n')
else:
# Python built with NDEBUG macro defined:
# test _Py_CheckFunctionResult() instead.
self.assertIn('returned a result with an exception set', err)
def test_buildvalue_N(self):
_testcapi.test_buildvalue_N()
@ -551,7 +584,7 @@ class CAPITest(unittest.TestCase):
with support.SuppressCrashReport():
rc, out, err = assert_python_failure('-sSI', '-c', code)
err = err.replace(b'\r', b'').decode('ascii', 'replace')
err = decode_stderr(err)
self.assertIn('Fatal Python error: test_fatal_error: MESSAGE\n',
err)

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@ -4736,6 +4736,18 @@ return_result_with_error(PyObject *self, PyObject *args)
Py_RETURN_NONE;
}
static PyObject*
getitem_with_error(PyObject *self, PyObject *args)
{
PyObject *map, *key;
if (!PyArg_ParseTuple(args, "OO", &map, &key)) {
return NULL;
}
PyErr_SetString(PyExc_ValueError, "bug");
return PyObject_GetItem(map, key);
}
static PyObject *
test_pytime_fromseconds(PyObject *self, PyObject *args)
{
@ -5901,10 +5913,9 @@ static PyMethodDef TestMethods[] = {
pymarshal_read_last_object_from_file, METH_VARARGS},
{"pymarshal_read_object_from_file",
pymarshal_read_object_from_file, METH_VARARGS},
{"return_null_without_error",
return_null_without_error, METH_NOARGS},
{"return_result_with_error",
return_result_with_error, METH_NOARGS},
{"return_null_without_error", return_null_without_error, METH_NOARGS},
{"return_result_with_error", return_result_with_error, METH_NOARGS},
{"getitem_with_error", getitem_with_error, METH_VARARGS},
{"PyTime_FromSeconds", test_pytime_fromseconds, METH_VARARGS},
{"PyTime_FromSecondsObject", test_pytime_fromsecondsobject, METH_VARARGS},
{"PyTime_AsSecondsDouble", test_pytime_assecondsdouble, METH_VARARGS},

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@ -1,11 +1,12 @@
/* Abstract Object Interface (many thanks to Jim Fulton) */
#include "Python.h"
#include "pycore_unionobject.h" // _Py_UnionType && _Py_Union()
#include "pycore_abstract.h" // _PyIndex_Check()
#include "pycore_ceval.h" // _Py_EnterRecursiveCall()
#include "pycore_object.h" // _Py_CheckSlotResult()
#include "pycore_pyerrors.h" // _PyErr_Occurred()
#include "pycore_pystate.h" // _PyThreadState_GET()
#include "pycore_unionobject.h" // _Py_UnionType && _Py_Union()
#include <ctype.h>
#include <stddef.h> // offsetof()
#include "longintrepr.h"
@ -61,7 +62,7 @@ PyObject_Size(PyObject *o)
m = Py_TYPE(o)->tp_as_sequence;
if (m && m->sq_length) {
Py_ssize_t len = m->sq_length(o);
assert(len >= 0 || PyErr_Occurred());
assert(_Py_CheckSlotResult(o, "__len__", len >= 0));
return len;
}
@ -160,7 +161,7 @@ PyObject_GetItem(PyObject *o, PyObject *key)
m = Py_TYPE(o)->tp_as_mapping;
if (m && m->mp_subscript) {
PyObject *item = m->mp_subscript(o, key);
assert((item != NULL) ^ (PyErr_Occurred() != NULL));
assert(_Py_CheckSlotResult(o, "__getitem__", item != NULL));
return item;
}
@ -1564,7 +1565,7 @@ PySequence_Size(PyObject *s)
m = Py_TYPE(s)->tp_as_sequence;
if (m && m->sq_length) {
Py_ssize_t len = m->sq_length(s);
assert(len >= 0 || PyErr_Occurred());
assert(_Py_CheckSlotResult(s, "__len__", len >= 0));
return len;
}
@ -1708,8 +1709,8 @@ PySequence_GetItem(PyObject *s, Py_ssize_t i)
if (i < 0) {
if (m->sq_length) {
Py_ssize_t l = (*m->sq_length)(s);
assert(_Py_CheckSlotResult(s, "__len__", l >= 0));
if (l < 0) {
assert(PyErr_Occurred());
return NULL;
}
i += l;
@ -1762,8 +1763,8 @@ PySequence_SetItem(PyObject *s, Py_ssize_t i, PyObject *o)
if (i < 0) {
if (m->sq_length) {
Py_ssize_t l = (*m->sq_length)(s);
assert(_Py_CheckSlotResult(s, "__len__", l >= 0));
if (l < 0) {
assert(PyErr_Occurred());
return -1;
}
i += l;
@ -1795,8 +1796,8 @@ PySequence_DelItem(PyObject *s, Py_ssize_t i)
if (i < 0) {
if (m->sq_length) {
Py_ssize_t l = (*m->sq_length)(s);
assert(_Py_CheckSlotResult(s, "__len__", l >= 0));
if (l < 0) {
assert(PyErr_Occurred());
return -1;
}
i += l;
@ -2145,7 +2146,7 @@ PyMapping_Size(PyObject *o)
m = Py_TYPE(o)->tp_as_mapping;
if (m && m->mp_length) {
Py_ssize_t len = m->mp_length(o);
assert(len >= 0 || PyErr_Occurred());
assert(_Py_CheckSlotResult(o, "__len__", len >= 0));
return len;
}

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@ -39,16 +39,16 @@ _Py_CheckFunctionResult(PyThreadState *tstate, PyObject *callable,
if (!_PyErr_Occurred(tstate)) {
if (callable)
_PyErr_Format(tstate, PyExc_SystemError,
"%R returned NULL without setting an error",
"%R returned NULL without setting an exception",
callable);
else
_PyErr_Format(tstate, PyExc_SystemError,
"%s returned NULL without setting an error",
"%s returned NULL without setting an exception",
where);
#ifdef Py_DEBUG
/* Ensure that the bug is caught in debug mode.
Py_FatalError() logs the SystemError exception raised above. */
Py_FatalError("a function returned NULL without setting an error");
Py_FatalError("a function returned NULL without setting an exception");
#endif
return NULL;
}
@ -60,17 +60,17 @@ _Py_CheckFunctionResult(PyThreadState *tstate, PyObject *callable,
if (callable) {
_PyErr_FormatFromCauseTstate(
tstate, PyExc_SystemError,
"%R returned a result with an error set", callable);
"%R returned a result with an exception set", callable);
}
else {
_PyErr_FormatFromCauseTstate(
tstate, PyExc_SystemError,
"%s returned a result with an error set", where);
"%s returned a result with an exception set", where);
}
#ifdef Py_DEBUG
/* Ensure that the bug is caught in debug mode.
Py_FatalError() logs the SystemError exception raised above. */
Py_FatalError("a function returned a result with an error set");
Py_FatalError("a function returned a result with an exception set");
#endif
return NULL;
}
@ -79,6 +79,30 @@ _Py_CheckFunctionResult(PyThreadState *tstate, PyObject *callable,
}
int
_Py_CheckSlotResult(PyObject *obj, const char *slot_name, int success)
{
PyThreadState *tstate = _PyThreadState_GET();
if (!success) {
if (!_PyErr_Occurred(tstate)) {
_Py_FatalErrorFormat(__func__,
"Slot %s of type %s failed "
"without setting an exception",
slot_name, Py_TYPE(obj)->tp_name);
}
}
else {
if (_PyErr_Occurred(tstate)) {
_Py_FatalErrorFormat(__func__,
"Slot %s of type %s succeeded "
"with an exception set",
slot_name, Py_TYPE(obj)->tp_name);
}
}
return 1;
}
/* --- Core PyObject call functions ------------------------------- */
/* Call a callable Python object without any arguments */