In the main branch, the function _tracemalloc__get_object_traceback doesn't account for objects with preheaders:

This means that when running with tracemalloc some allocation tracebacks are missing:

import warnings

class MyClass:
    def __del__(self):
        warnings.warn("Uh oh", ResourceWarning, source=self)

def func():
    m = MyClass()

func()

python3 -Wd -X tracemalloc=2 example.py

cc @markshannon

Linked PRs

• gh-101430: Update tracemalloc to handle presize properly. #101745