STINNER Victor <vstin...@redhat.com> added the comment:

Yury, Andrew, Ned: I set the priority to release blocker because I'm scared by 
what I saw. The START TLS has a race condition in its ProactorEventLoop 
implementation. But the bug doesn't see to be specific to START TLS, but rather 
to transport.set_transport(), and even more generally to 
transport.pause_reading() / transport.resume_reading(). The bug is quite 
severe: we loose data and it's really hard to know why (I spent a few hours to 
add many many print and try to reproduce on a very tiny reliable unit test). As 
an asyncio user, I expect that transports are 100% reliable, and I would first 
look into my look (like looking into start_tls() implementation in my case).

If the bug was very specific to start_tls(), I would suggest to "just" 
"disable" start_tls() on ProactorEventLoop (sorry, Windows!). But since the 
data loss seems to concern basically any application using ProactorEventLoop, I 
don't see any simple workaround.

My hope is that a fix can be written shortly to not block the 3.7.0 final 
release for too long :-(

Yury, Andrew: Can you please just confirm that it's a regression and that a 
release blocker is justified?

----------
nosy: +ned.deily
priority: normal -> release blocker

_______________________________________
Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue33694>
_______________________________________
_______________________________________________
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

Reply via email to