Long story short, I've discovered that asyncio is broken in 3.5.2. Specifically, there is a callbacks race in `loop.sock_connect` which can make subsequent `loop.sock_sendall` calls to hang forever. This thing is very tricky and hard to detect and debug; I had to spend a few hours investigating what's going on with a failing unittest in uvloop (asyncio-compatible event loop). I can only imagine how hard it would be to understand what's going on in a larger codebase.
For those who is interested, here's a PR for asyncio repo: https://github.com/python/asyncio/pull/366 It explains the bug in detail and there has a proposed patch to fix the problem. Larry and the release team: would it be possible to make an "emergency" 3.5.3 release? Going forward, we need to increase the number of functional tests for asyncio, as most of the current tests use mocks. I'm going to port all functional tests from uvloop to asyncio as a start. Yury _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
