Skip to content

[3.15] gh-155146: Do not depend on the exact number of allocations in test_class (GH-155150) #155155

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
hugovk merged 1 commit into from
Aug 8, 2026
Merged

[3.15] gh-155146: Do not depend on the exact number of allocations in test_class (GH-155150) #155155

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
gh-155146: Do not depend on the exact number of allocations in test_c… 
…lass (GH-155150)

Try to fail every one of the first allocations and accept the first one which
fails in the code detaching the instance dictionary from the object, instead
of assuming that this is the first allocation after set_nomemory().

Run the test with the test.support.isolation.runInSubprocess() decorator
instead of executing it as a source string in a subprocess.
(cherry picked from commit 416c346)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
  • Loading branch information
@serhiy-storchaka @claude @miss-islington
2 people authored and miss-islington committed Aug 4, 2026
commit 4c0a39728436bf90d2f6222c1faa4524e4c46ba4
57 changes: 34 additions & 23 deletions Lib/test/test_class.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@

import unittest
from test import support
from test.support import cpython_only, import_helper, script_helper
from test.support import cpython_only, import_helper, isolation

testmeths = [

Expand Down Expand Up @@ -1014,32 +1014,43 @@ class C:
C.a = X()

@support.nomemtest
@isolation.runInSubprocess()
def test_detach_materialized_dict_no_memory(self):
code = """if 1:
import test.support
import _testcapi
class A:
def __init__(self):
self.a = 1
self.b = 2
import _testcapi

class A:
def __init__(self):
self.a = 1
self.b = 2

# The failing allocation should be the one which detaches the
# dictionary from the object, but other allocations can happen
# first, so try to fail every one of the first allocations.
raised = False
for n in range(20):
a = A()
d = a.__dict__
with test.support.catch_unraisable_exception() as ex:
_testcapi.set_nomemory(0, 1)
del a
assert ex.unraisable.exc_type is MemoryError
try:
d["a"]
except KeyError:
pass
else:
assert False, "KeyError not raised"
"""
rc, out, err = script_helper.assert_python_ok("-c", code)
self.assertEqual(rc, 0)
self.assertFalse(out, msg=out.decode('utf-8'))
self.assertFalse(err, msg=err.decode('utf-8'))
with support.catch_unraisable_exception() as ex:
_testcapi.set_nomemory(n, n + 1)
try:
del a
finally:
_testcapi.remove_mem_hooks()
exc_type = ex.unraisable and ex.unraisable.exc_type
except MemoryError:
# The failing allocation was not in the deallocation code.
continue
if exc_type is not MemoryError:
continue
raised = True
if "a" not in d:
# The dictionary was cleared, as expected.
break
else:
if not raised:
self.fail("MemoryError was not raised during deallocation")
self.fail("the dictionary was not cleared")

if __name__ == '__main__':
unittest.main()
Loading