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[3.13] gh-148450: abc.register needs to update type_version when tp_flags is changed (GH-148623) #150307

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Merged
kumaraditya303 merged 3 commits into from
May 23, 2026
+30 −0
Merged

[3.13] gh-148450: abc.register needs to update type_version when tp_flags is changed (GH-148623) #150307

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6f9bd80
backup 3.13
cocolato Apr 16, 2026
264f265
📜🤖 Added by blurb_it.
blurb-it[bot] May 23, 2026
16d468b
Merge branch '3.13' into local-3.13
cocolato May 23, 2026
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20 changes: 20 additions & 0 deletions Lib/test/test_type_cache.py
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Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
""" Tests for the internal type cache in CPython. """
import collections.abc
import unittest
import dis
from test import support
Expand Down Expand Up @@ -108,6 +109,25 @@ class HolderSub(Holder):
Holder.set_value()
HolderSub.value

def test_abc_register_invalidates_subclass_versions(self):
class Parent:
pass

class Child(Parent):
pass

type_assign_version(Parent)
type_assign_version(Child)
parent_version = type_get_version(Parent)
child_version = type_get_version(Child)
if parent_version == 0 or child_version == 0:
self.skipTest("Could not assign valid type versions")

collections.abc.Mapping.register(Parent)

self.assertEqual(type_get_version(Parent), 0)
self.assertEqual(type_get_version(Child), 0)

@support.cpython_only
@requires_specialization
class TypeCacheWithSpecializationTests(unittest.TestCase):
Expand Down
1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Core_and_Builtins/2026-05-23-09-55-50.gh-issue-148450.2MEVqH.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
Fix ``abc.register()`` so it invalidates type version tags for registered classes.
9 changes: 9 additions & 0 deletions Objects/typeobject.c
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Expand Up @@ -5398,6 +5398,15 @@ void
_PyType_SetFlagsRecursive(PyTypeObject *self, unsigned long mask, unsigned long flags)
{
BEGIN_TYPE_LOCK();
/* Ideally, changing flags and invalidating the old version tag would
happen in one step. For this backport, keep it simple and invalidate
first while holding TYPE_LOCK. Immutable types are skipped because
set_flags_recursive() does not modify them. */
if (!PyType_HasFeature(self, Py_TPFLAGS_IMMUTABLETYPE) &&
(self->tp_flags & mask) != flags)
{
type_modified_unlocked(self);
}
set_flags_recursive(self, mask, flags);
END_TYPE_LOCK();
}
Expand Down