https://github.com/python/cpython/commit/bce9df97d5349e351666055bd797c99e55a1770a commit: bce9df97d5349e351666055bd797c99e55a1770a branch: 3.12 author: Miss Islington (bot) <31488909+miss-isling...@users.noreply.github.com> committer: encukou <encu...@gmail.com> date: 2024-10-29T14:15:09+01:00 summary:
[3.12] gh-125783: Add tests to prevent regressions with the combination of `ctypes` and metaclasses. (GH-125881) (GH-125988) cherry picked from commit 13844094609cf8265a2eed023e33c7002f3f530d by Jun Komoda Also: Add test_ctypes/_support.py from 3.13+ This partially backports be89ee5649031e08f191bf596fa20a09c5698079 (https://github.com/python/cpython/pull/113727) by AN Long Co-authored-by: Jun Komoda <45822440+jun...@users.noreply.github.com> Co-authored-by: AN Long <a...@users.noreply.github.com> Co-authored-by: Erlend E. Aasland <erlend.aasl...@protonmail.com> files: A Lib/test/test_ctypes/_support.py A Lib/test/test_ctypes/test_c_simple_type_meta.py diff --git a/Lib/test/test_ctypes/_support.py b/Lib/test/test_ctypes/_support.py new file mode 100644 index 00000000000000..e4c2b33825ae8f --- /dev/null +++ b/Lib/test/test_ctypes/_support.py @@ -0,0 +1,24 @@ +# Some classes and types are not export to _ctypes module directly. + +import ctypes +from _ctypes import Structure, Union, _Pointer, Array, _SimpleCData, CFuncPtr + + +_CData = Structure.__base__ +assert _CData.__name__ == "_CData" + +class _X(Structure): + _fields_ = [("x", ctypes.c_int)] +CField = type(_X.x) + +# metaclasses +PyCStructType = type(Structure) +UnionType = type(Union) +PyCPointerType = type(_Pointer) +PyCArrayType = type(Array) +PyCSimpleType = type(_SimpleCData) +PyCFuncPtrType = type(CFuncPtr) + +# type flags +Py_TPFLAGS_DISALLOW_INSTANTIATION = 1 << 7 +Py_TPFLAGS_IMMUTABLETYPE = 1 << 8 diff --git a/Lib/test/test_ctypes/test_c_simple_type_meta.py b/Lib/test/test_ctypes/test_c_simple_type_meta.py new file mode 100644 index 00000000000000..fa5144a3ca01bb --- /dev/null +++ b/Lib/test/test_ctypes/test_c_simple_type_meta.py @@ -0,0 +1,87 @@ +import unittest +import ctypes +from ctypes import POINTER, c_void_p + +from ._support import PyCSimpleType + + +class PyCSimpleTypeAsMetaclassTest(unittest.TestCase): + def tearDown(self): + # to not leak references, we must clean _pointer_type_cache + ctypes._reset_cache() + + def test_creating_pointer_in_dunder_new_1(self): + # Test metaclass whose instances are C types; when the type is + # created it automatically creates a pointer type for itself. + # The pointer type is also an instance of the metaclass. + # Such an implementation is used in `IUnknown` of the `comtypes` + # project. See gh-124520. + + class ct_meta(type): + def __new__(cls, name, bases, namespace): + self = super().__new__(cls, name, bases, namespace) + + # Avoid recursion: don't set up a pointer to + # a pointer (to a pointer...) + if bases == (c_void_p,): + # When creating PtrBase itself, the name + # is not yet available + return self + if issubclass(self, PtrBase): + return self + + if bases == (object,): + ptr_bases = (self, PtrBase) + else: + ptr_bases = (self, POINTER(bases[0])) + p = p_meta(f"POINTER({self.__name__})", ptr_bases, {}) + ctypes._pointer_type_cache[self] = p + return self + + class p_meta(PyCSimpleType, ct_meta): + pass + + class PtrBase(c_void_p, metaclass=p_meta): + pass + + class CtBase(object, metaclass=ct_meta): + pass + + class Sub(CtBase): + pass + + class Sub2(Sub): + pass + + self.assertIsInstance(POINTER(Sub2), p_meta) + self.assertTrue(issubclass(POINTER(Sub2), Sub2)) + self.assertTrue(issubclass(POINTER(Sub2), POINTER(Sub))) + self.assertTrue(issubclass(POINTER(Sub), POINTER(CtBase))) + + def test_creating_pointer_in_dunder_new_2(self): + # A simpler variant of the above, used in `CoClass` of the `comtypes` + # project. + + class ct_meta(type): + def __new__(cls, name, bases, namespace): + self = super().__new__(cls, name, bases, namespace) + if isinstance(self, p_meta): + return self + p = p_meta(f"POINTER({self.__name__})", (self, c_void_p), {}) + ctypes._pointer_type_cache[self] = p + return self + + class p_meta(PyCSimpleType, ct_meta): + pass + + class Core(object): + pass + + class CtBase(Core, metaclass=ct_meta): + pass + + class Sub(CtBase): + pass + + self.assertIsInstance(POINTER(Sub), p_meta) + self.assertTrue(issubclass(POINTER(Sub), Sub)) _______________________________________________ Python-checkins mailing list -- python-checkins@python.org To unsubscribe send an email to python-checkins-le...@python.org https://mail.python.org/mailman3/lists/python-checkins.python.org/ Member address: arch...@mail-archive.com
