There seem to be at least two different issues raised here (and in Issue 34547):

1. Double exceptions due to “self.environ” and “self.status” being None when the error handler is called. This problem was specifically raised in Issue 29183.

2. What to do about exceptions such as ConnectionAbortedError, which are caused by the network or the client, and are outside the server’s control. I find it annoying when these exceptions are logged, and tend to add handlers for these exception types to silence them. I think this is what Petter is trying to do in <https://github.com/python/cpython/pull/9713>.