tzickel <icebreak@yahoo.com> added the comment: It actually makes tons of sense that while the thread is running, that the object representing it is alive. After the thread finishes its work, the object dies.

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import time, threading, weakref, gc t = threading.Thread(target=time.sleep, args=(10,)) wr = weakref.ref(t) t.start() del t gc.collect() wr() <Thread(Thread-1, started 139937234327296)> Wait 10 seconds... gc.collect() wr()

The thread is gone (which doesn't happen with the pool). Anyhow, I've submitted a patch to fix the bug that was introduced 9 years ago on GH, feel free to check it. ---------- _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue34172> _______________________________________