[New-bugs-announce] [issue26617] Assertion failed in gc with __del__ and weakref

[Guo, Jiahua]

New submission from Guo, Jiahua:

$ python3.5-dbg crash.py
python3.5-dbg: ../Modules/gcmodule.c:364: update_refs: Assertion `((gc)->gc.gc_refs >> (1)) != 0' failed.


$ python3.5-dbg crash-multithread.py
python3.5-dbg: ../Modules/gcmodule.c:364: update_refs: Assertion `((gc)->gc.gc_refs >> (1)) != 0' failed.


============ crash.py ==========
import weakref
import gc


def callback(o):
    gc.collect()


class C:
    def __del__(self):
        pass

def main():
    c = C()
    cref = weakref.ref(c, callback)
    del c


main()


============ crash-multithread.py ==========
import threading
import weakref
import gc


ei = threading.Event()
eo = threading.Event()


def gc_worker():
    ei.wait()
    gc.collect()
    eo.set()


def callback(o):
    ei.set()
    eo.wait()


class C:
    def __del__(self):
        pass


def main():
    t = threading.Thread(target=gc_worker)
    t.start()
    c = C()
    cref = weakref.ref(c, callback)
    del c
    t.join()


main()

----------
components: Interpreter Core
messages: 262242
nosy: Guo, Jiahua
priority: normal
severity: normal
status: open
title: Assertion failed in gc with __del__ and weakref
type: crash
versions: Python 3.4, Python 3.5

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue26617>
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