I tested the same script in ubuntu and got the following.

==1361==ASan runtime does not come first in initial library list; you should either link runtime to your application or manually preload it with LD_PRELOAD.

While on windows he does not complain about ASan runtime not bein first in initial library list.

Once I use LD_PRELOAD in linux. Lsan detected memory leaks, after suppressing them with LSAN_OPTIONS=detect_leaks=0, the script ran fine.

So far I could not find an LD_PRELOAD equivalent in windows.

I am suspecting if one would compile python with asan and run the test on windows, I would get similar results as in linux. Sadly at the moment asan suppressions doesn't seem to work on windows.

I think this is not a real bug on python but the way we are loading asan-rt in windows. Once I am sure I will colse this bug.