call of __del__ non-deterministic in python 2.4 (cpython)?

H

Holger Joukl

Hi all,

I've recently run into a problem that I haven't seen with python 1.5.2 and
python 2.3.
It seems that under certain conditions __del__ does not get immediately
called when a local variable goes out of scope.

I ended up with deadlocks in a threaded application because a locked
section
was supposed to be entered from within __del__ but apparently the same
thread
(the main thread, in that case) was already holding that lock.

The result looked really strange with the main thread entering the locked
section and
then suddenly the delayed call of __del__ taking control, also wanting to
acquire
the lock but never being able to.

Unfortunately I fail to put together a minimal example.

Anyway: Is relying on __del__ getting called immediately when the refcount
drops to 0 a no-no?
If so should that maybe be prominently stated in the docs?

Cheers,
Holger

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