https://github.com/python/cpython/commit/25518f51dc9fd3ffe4f8ae5d53baa3728936be2b
commit: 25518f51dc9fd3ffe4f8ae5d53baa3728936be2b
branch: main
author: Sergey Miryanov <sergey.mirya...@gmail.com>
committer: nascheme <nas-git...@arctrix.com>
date: 2025-08-07T17:45:33-07:00
summary:
GH-135552: Add tests to check weakref clearing (GH-136304)
These are tests to ensure behaviour introduced by GH-136189 is working as
expected.
Co-authored-by: Mikhail Borisov <43937008+fxeqxmu...@users.noreply.github.com>
Co-authored-by: Kumar Aditya <kumaradi...@python.org>
Co-authored-by: Neil Schemenauer <nas-git...@arctrix.com>
files:
M Lib/test/test_gc.py
M Lib/test/test_weakref.py
diff --git a/Lib/test/test_gc.py b/Lib/test/test_gc.py
index 3ec211531c4c70..7c9adf3049a131 100644
--- a/Lib/test/test_gc.py
+++ b/Lib/test/test_gc.py
@@ -1155,6 +1155,37 @@ def test_something(self):
""")
assert_python_ok("-c", source)
+ def test_do_not_cleanup_type_subclasses_before_finalization(self):
+ # See https://github.com/python/cpython/issues/135552
+ # If we cleanup weakrefs for tp_subclasses before calling
+ # the finalizer (__del__) then the line `fail = BaseNode.next.next`
+ # should fail because we are trying to access a subclass
+ # attribute. But subclass type cache was not properly invalidated.
+ code = """
+ class BaseNode:
+ def __del__(self):
+ BaseNode.next = BaseNode.next.next
+ fail = BaseNode.next.next
+
+ class Node(BaseNode):
+ pass
+
+ BaseNode.next = Node()
+ BaseNode.next.next = Node()
+ """
+ # this test checks garbage collection while interp
+ # finalization
+ assert_python_ok("-c", textwrap.dedent(code))
+
+ code_inside_function = textwrap.dedent(F"""
+ def test():
+ {textwrap.indent(code, ' ')}
+
+ test()
+ """)
+ # this test checks regular garbage collection
+ assert_python_ok("-c", code_inside_function)
+
class IncrementalGCTests(unittest.TestCase):
@unittest.skipIf(_testinternalcapi is None, "requires _testinternalcapi")
diff --git a/Lib/test/test_weakref.py b/Lib/test/test_weakref.py
index 4c7c900eb56ae1..47f6b46061ac30 100644
--- a/Lib/test/test_weakref.py
+++ b/Lib/test/test_weakref.py
@@ -1044,6 +1044,32 @@ def callback(obj):
stderr = res.err.decode("ascii", "backslashreplace")
self.assertNotRegex(stderr, "_Py_Dealloc: Deallocator of type
'TestObj'")
+ def test_clearing_weakrefs_in_gc(self):
+ # This test checks that when finalizers are called:
+ # 1. weakrefs with callbacks have been cleared
+ # 2. weakrefs without callbacks have not been cleared
+ errors = []
+ def test():
+ class Class:
+ def __init__(self):
+ self._self = self
+ self.wr1 = weakref.ref(Class, lambda x: None)
+ self.wr2 = weakref.ref(Class)
+
+ def __del__(self):
+ # we can't use assert* here, because gc will swallow
+ # exceptions
+ if self.wr1() is not None:
+ errors.append("weakref with callback as cleared")
+ if self.wr2() is not Class:
+ errors.append("weakref without callback was cleared")
+
+ Class()
+
+ test()
+ gc.collect()
+ self.assertEqual(errors, [])
+
class SubclassableWeakrefTestCase(TestBase):
_______________________________________________
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
