Fatal exception: ConnectionResetError

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Disclaimer: I don't know if you're interested in feedback on Tulip at this 
point. If you aren't, just tell me, I'll stop bugging you until you release an 
alpha :)

Context: I'm testing a WebSocket client running on Tulip against the AutoBahn 
test suite (which runs on Twisted) on OS X.

Problem: I encounter the following error:

Fatal error for <tulip.selector_events._SelectorSocketTransport object at 
0x10c0c1b50>
Traceback (most recent call last):
  File "/Users/myk/Documents/dev/tulip/tulip/selector_events.py", line 336, in _read_ready
    data = self._sock.recv(16*1024)
ConnectionResetError: [Errno 54] Connection reset by peer

Analysis:

`_SelectorSocketTransport._read_ready` expects `recv` to return an empty 
bytestring when the end of the stream is reached. In this case, `recv` raises 
an exception instead.

I could confirm that the connection is being closed in `KqueueSelector.select`, 
because at that point `kev.flags` has the `KQ_EV_EOF` bit set. But that doesn't 
appear to be the right place to handle this condition.

I think this problem has to do with the way the TCP connection is shut down. I 
haven't managed to reproduce the problem with other servers. Still, it 
shouldn't result in a fatal exception.

Reproduction:

Here's the simplest way to trigger the exception I have to offer — sorry :/

In a shell:

% mkvirtualenv --python=python2.7 autobahn
% pip install autobahntestsuite
% wstest -m fuzzingserver

In another shell:

% python3.3 dummy_client.py        # see below

After a few seconds wstest times out, closes the connection and dummy_client.py 
displays the stack trace.

------------------------------------------------------------------------
# dummy_client.py

import tulip

class DummyProtocol(tulip.Protocol):
    def connection_made(self, transport):
        self.transport = transport
        self.stream = tulip.StreamReader()

    def data_received(self, data):
        self.stream.feed_data(data)

    def eof_received(self):
        self.stream.feed_eof()
        self.transport.close()

loop = tulip.get_event_loop()

def main():
    trans, proto = yield from loop.create_connection(
            DummyProtocol, 'localhost', 9001)
    yield from proto.stream.read()

loop.run_until_complete(main())
------------------------------------------------------------------------

Original issue reported on code.google.com by aymeric....@polytechnique.org on 3 Apr 2013 at 5:41