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gh-119775: Remove ability to create immutable types with mutable bases #119776

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Merged
sobolevn merged 4 commits into from
Jun 2, 2024
Merged

gh-119775: Remove ability to create immutable types with mutable bases #119776

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121bb1b
gh-119775: Remove ability to create immutable types with mutable bases
sobolevn May 30, 2024
d03ae98
Address review
sobolevn Jun 1, 2024
93c06df
Remove method
sobolevn Jun 1, 2024
7dd8471
Merge branch 'main' into issue-119775
sobolevn Jun 2, 2024
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2 changes: 2 additions & 0 deletions Doc/whatsnew/3.14.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -254,3 +254,5 @@ Deprecated
Removed
-------

* Creating :c:data:`immutable types <Py_TPFLAGS_IMMUTABLETYPE>` with mutable
bases was deprecated since 3.12 and now raises a :exc:`TypeError`.
22 changes: 3 additions & 19 deletions Lib/test/test_capi/test_misc.py
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Expand Up @@ -777,33 +777,17 @@ def test_pytype_fromspec_with_repeated_slots(self):
with self.assertRaises(SystemError):
_testcapi.create_type_from_repeated_slots(variant)

@warnings_helper.ignore_warnings(category=DeprecationWarning)
def test_immutable_type_with_mutable_base(self):
# Add deprecation warning here so it's removed in 3.14
warnings._deprecated(
'creating immutable classes with mutable bases', remove=(3, 14))

class MutableBase:
def meth(self):
return 'original'

with self.assertWarns(DeprecationWarning):
ImmutableSubclass = _testcapi.make_immutable_type_with_base(
MutableBase)
instance = ImmutableSubclass()

self.assertEqual(instance.meth(), 'original')

# Cannot override the static type's method
with self.assertRaisesRegex(
TypeError,
"cannot set 'meth' attribute of immutable type"):
ImmutableSubclass.meth = lambda self: 'overridden'
self.assertEqual(instance.meth(), 'original')
with self.assertRaisesRegex(TypeError, 'Creating immutable type'):
_testcapi.make_immutable_type_with_base(MutableBase)

# Can change the method on the mutable base
MutableBase.meth = lambda self: 'changed'
self.assertEqual(instance.meth(), 'changed')
self.assertEqual(MutableBase().meth(), 'changed')
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def test_pynumber_tobase(self):
from _testcapi import pynumber_tobase
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2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/C API/2024-05-30-12-51-21.gh-issue-119775.CBq9IG.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
Creating :c:data:`immutable types <Py_TPFLAGS_IMMUTABLETYPE>` with mutable
bases was deprecated since 3.12 and now raises a :exc:`TypeError`.
15 changes: 6 additions & 9 deletions Objects/typeobject.c
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Expand Up @@ -4613,16 +4613,13 @@ _PyType_FromMetaclass_impl(
goto finally;
}
if (!_PyType_HasFeature(b, Py_TPFLAGS_IMMUTABLETYPE)) {
if (PyErr_WarnFormat(
PyExc_DeprecationWarning,
0,
"Creating immutable type %s from mutable base %s is "
"deprecated, and slated to be disallowed in Python 3.14.",
PyErr_Format(
PyExc_TypeError,
"Creating immutable type %s from mutable base %s",
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spec->name,
b->tp_name))
{
goto finally;
}
b->tp_name
);
goto finally;
}
}
}
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