MQTT: OSError: -1 from line 160, in wait_msg

[semireg]

I've searched the forums and this is the closest post to what I'm experiencing:

• https://forum.pycom.io/topic/1592/oserror-1/4

This is on a new WiPy 3.0 with default MQTT library. This also happens using the other version from micropython-lib (https://github.com/micropython/micropython-lib/blob/master/umqtt.simple/umqtt/simple.py).

I've tried setting timeout to different values, no luck. This code was working fine on an ESP8266. Thoughts?

(sysname='WiPy', nodename='WiPy', release='1.11.0.b1', version='3032601 on 2017-12-30', machine='WiPy with ESP32')

Here's the relevant code:

    # Wait for a single incoming MQTT message and process it.
    # Subscribed messages are delivered to a callback previously
    # set by .set_callback() method. Other (internal) MQTT
    # messages processed internally.
    def wait_msg(self):
        res = self.sock.read(1)
        self.sock.setblocking(True)
        if res is None:
            return None
        if res == b"":
            raise OSError(-1) # <-- LINE 160
        if res == b"\xd0":  # PINGRESP
            sz = self.sock.read(1)[0]
            assert sz == 0
            return None

My guess is the socket implementation has a bug - it should return None instead of a zero length bytes object. If that's the case, a quick fix would be to make the check less strict:

 if res is None or res == b"":
            return None

This seems to work OK... What are the implications for relaxing this check?

[daniel]

@semireg We'll have a look to see if there's a bug in the socket implementation.