gh-112358: Fix Python 3.12 regression with subclassing struct.Struct. (#112424)

Revert commit c8c0afc713 (PR #94532),
which moved `struct.Struct` initialisation from `Struct.__init__` to `Struct.__new__`.
This caused issues with code in the wild that subclasses `struct.Struct`.
This commit is contained in:
Mark Dickinson 2023-11-26 14:29:52 +00:00 committed by GitHub
parent 3faf8e586d
commit 9fe60340d7
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4 changed files with 52 additions and 48 deletions

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@ -700,20 +700,6 @@ class StructTest(unittest.TestCase):
with self.assertRaises(TypeError):
cls.x = 1
@support.cpython_only
def test__struct_Struct__new__initialized(self):
# See https://github.com/python/cpython/issues/78724
s = struct.Struct.__new__(struct.Struct, "b")
s.unpack_from(b"abcd")
@support.cpython_only
def test__struct_Struct_subclassing(self):
class Bob(struct.Struct):
pass
s = Bob("b")
s.unpack_from(b"abcd")
def test_issue35714(self):
# Embedded null characters should not be allowed in format strings.
@ -774,6 +760,15 @@ class StructTest(unittest.TestCase):
test_error_propagation('N')
test_error_propagation('n')
def test_struct_subclass_instantiation(self):
# Regression test for https://github.com/python/cpython/issues/112358
class MyStruct(struct.Struct):
def __init__(self):
super().__init__('>h')
my_struct = MyStruct()
self.assertEqual(my_struct.pack(12345), b'\x30\x39')
def test_repr(self):
s = struct.Struct('=i2H')
self.assertEqual(repr(s), f'Struct({s.format!r})')