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gh-62260: Fix ctypes.Structure subclassing with multiple layers (GH-13374)

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The length field of StgDictObject for Structure class contains now
the total number of items in ffi_type_pointer.elements (excluding
the trailing null).

The old behavior of using the number of elements in the parent class can
cause the array to be truncated when it is copied, especially when there
are multiple layers of subclassing.

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
This commit is contained in:
Jeffrey Kintscher 2024-01-01 08:24:24 -08:00 • committed by GitHub
parent 4036e48d59
commit 5f3cc90a12
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4 changed files with 70 additions and 7 deletions
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63
Lib/test/test_ctypes/test_structures.py
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@ -1,5 +1,5 @@
import _ctypes_test
import platform
from platform import architecture as _architecture
import struct
import sys
import unittest
@ -8,6 +8,7 @@ from ctypes import (CDLL, Array, Structure, Union, POINTER, sizeof, byref, align
c_uint8, c_uint16, c_uint32,
c_short, c_ushort, c_int, c_uint,
c_long, c_ulong, c_longlong, c_ulonglong, c_float, c_double)
from ctypes.util import find_library
from struct import calcsize
from collections import namedtuple
from test import support
@ -472,6 +473,66 @@ class StructureTestCase(unittest.TestCase):
self.assertEqual(s.first, got.first)
self.assertEqual(s.second, got.second)
def _test_issue18060(self, Vector):
# The call to atan2() should succeed if the
# class fields were correctly cloned in the
# subclasses. Otherwise, it will segfault.
if sys.platform == 'win32':
libm = CDLL(find_library('msvcrt.dll'))
else:
libm = CDLL(find_library('m'))
libm.atan2.argtypes = [Vector]
libm.atan2.restype = c_double
arg = Vector(y=0.0, x=-1.0)
self.assertAlmostEqual(libm.atan2(arg), 3.141592653589793)
@unittest.skipIf(_architecture() == ('64bit', 'WindowsPE'), "can't test Windows x64 build")
@unittest.skipUnless(sys.byteorder == 'little', "can't test on this platform")
def test_issue18060_a(self):
# This test case calls
# PyCStructUnionType_update_stgdict() for each
# _fields_ assignment, and PyCStgDict_clone()
# for the Mid and Vector class definitions.
class Base(Structure):
_fields_ = [('y', c_double),
('x', c_double)]
class Mid(Base):
pass
Mid._fields_ = []
class Vector(Mid): pass
self._test_issue18060(Vector)
@unittest.skipIf(_architecture() == ('64bit', 'WindowsPE'), "can't test Windows x64 build")
@unittest.skipUnless(sys.byteorder == 'little', "can't test on this platform")
def test_issue18060_b(self):
# This test case calls
# PyCStructUnionType_update_stgdict() for each
# _fields_ assignment.
class Base(Structure):
_fields_ = [('y', c_double),
('x', c_double)]
class Mid(Base):
_fields_ = []
class Vector(Mid):
_fields_ = []
self._test_issue18060(Vector)
@unittest.skipIf(_architecture() == ('64bit', 'WindowsPE'), "can't test Windows x64 build")
@unittest.skipUnless(sys.byteorder == 'little', "can't test on this platform")
def test_issue18060_c(self):
# This test case calls
# PyCStructUnionType_update_stgdict() for each
# _fields_ assignment.
class Base(Structure):
_fields_ = [('y', c_double)]
class Mid(Base):
_fields_ = []
class Vector(Mid):
_fields_ = [('x', c_double)]
self._test_issue18060(Vector)
def test_array_in_struct(self):
# See bpo-22273